Daily bump.
[official-gcc.git] / gcc / tree-ssa-ter.c
blobf7ca95bb5af3300c4f858ffb80e00f1c18ae8143
1 /* Routines for performing Temporary Expression Replacement (TER) in SSA trees.
2 Copyright (C) 2003-2015 Free Software Foundation, Inc.
3 Contributed by Andrew MacLeod <amacleod@redhat.com>
5 This file is part of GCC.
7 GCC is free software; you can redistribute it and/or modify
8 it under the terms of the GNU General Public License as published by
9 the Free Software Foundation; either version 3, or (at your option)
10 any later version.
12 GCC is distributed in the hope that it will be useful,
13 but WITHOUT ANY WARRANTY; without even the implied warranty of
14 MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
15 GNU General Public License for more details.
17 You should have received a copy of the GNU General Public License
18 along with GCC; see the file COPYING3. If not see
19 <http://www.gnu.org/licenses/>. */
22 #include "config.h"
23 #include "system.h"
24 #include "coretypes.h"
25 #include "backend.h"
26 #include "tree.h"
27 #include "gimple.h"
28 #include "hard-reg-set.h"
29 #include "ssa.h"
30 #include "alias.h"
31 #include "fold-const.h"
32 #include "gimple-pretty-print.h"
33 #include "internal-fn.h"
34 #include "gimple-iterator.h"
35 #include "dumpfile.h"
36 #include "tree-ssa-live.h"
37 #include "tree-ssa-ter.h"
38 #include "tree-outof-ssa.h"
39 #include "flags.h"
40 #include "gimple-walk.h"
43 /* Temporary Expression Replacement (TER)
45 Replace SSA version variables during out-of-ssa with their defining
46 expression if there is only one use of the variable.
48 This pass is required in order for the RTL expansion pass to see larger
49 chunks of code. This allows it to make better choices on RTL pattern
50 selection. When expand is rewritten and merged with out-of-ssa, and
51 understands SSA, this should be eliminated.
53 A pass is made through the function, one block at a time. No cross block
54 information is tracked.
56 Variables which only have one use, and whose defining stmt is considered
57 a replaceable expression (see ssa_is_replaceable_p) are tracked to see whether
58 they can be replaced at their use location.
60 n_12 = C * 10
61 a_2 = b_5 + 6
62 v_9 = a_2 * n_12
64 if there are the only use of n_12 and a_2, TER will substitute in their
65 expressions in v_9, and end up with:
67 v_9 = (b_5 + 6) * (C * 10)
69 which will then have the ssa_name assigned to regular variables, and the
70 resulting code which will be passed to the expander looks something like:
72 v = (b + 6) * (C * 10)
75 This requires ensuring that none of the variables used by the expression
76 change between the def point and where it is used. Furthermore, if any
77 of the ssa_names used in this expression are themselves replaceable, we
78 have to ensure none of that expressions' arguments change either.
79 Although SSA_NAMES themselves don't change, this pass is performed after
80 coalescing has coalesced different SSA_NAMES together, so there could be a
81 definition of an SSA_NAME which is coalesced with a use that causes a
82 problem, i.e.,
84 PHI b_5 = <b_8(2), b_14(1)>
85 <...>
86 a_2 = b_5 + 6
87 b_8 = c_4 + 4
88 v_9 = a_2 * n_12
89 <...>
91 If b_5, b_8 and b_14 are all coalesced together...
92 The expression b_5 + 6 CANNOT replace the use in the statement defining v_9
93 because b_8 is in fact killing the value of b_5 since they share a partition
94 and will be assigned the same memory or register location.
96 TER implements this but stepping through the instructions in a block and
97 tracking potential expressions for replacement, and the partitions they are
98 dependent on. Expressions are represented by the SSA_NAME_VERSION of the
99 DEF on the LHS of a GIMPLE_ASSIGN and the expression is the RHS.
101 When a stmt is determined to be a possible replacement expression, the
102 following steps are taken:
104 EXPR_DECL_UID bitmap is allocated and set to the base variable UID of the
105 def and any uses in the expression. non-NULL means the expression is being
106 tracked. The UID's themselves are used to prevent TER substitution into
107 accumulating sequences, i.e.,
109 x = x + y
110 x = x + z
111 x = x + w
112 etc.
113 this can result in very large expressions which don't accomplish anything
114 see PR tree-optimization/17549.
116 PARTITION_DEPENDENCIES is another bitmap array, and it has a bit set for any
117 partition which is used in the expression. This is primarily used to remove
118 an expression from the partition kill lists when a decision is made whether
119 to replace it or not. This is indexed by ssa version number as well, and
120 indicates a partition number. virtual operands are not tracked individually,
121 but they are summarized by an artificial partition called VIRTUAL_PARTITION.
122 This means a MAY or MUST def will kill *ALL* expressions that are dependent
123 on a virtual operand.
124 Note that the EXPR_DECL_UID and this bitmap represent very similar
125 information, but the info in one is not easy to obtain from the other.
127 KILL_LIST is yet another bitmap array, this time it is indexed by partition
128 number, and represents a list of active expressions which will no
129 longer be valid if a definition into this partition takes place.
131 PARTITION_IN_USE is simply a bitmap which is used to track which partitions
132 currently have something in their kill list. This is used at the end of
133 a block to clear out the KILL_LIST bitmaps at the end of each block.
135 NEW_REPLACEABLE_DEPENDENCIES is used as a temporary place to store
136 dependencies which will be reused by the current definition. All the uses
137 on an expression are processed before anything else is done. If a use is
138 determined to be a replaceable expression AND the current stmt is also going
139 to be replaceable, all the dependencies of this replaceable use will be
140 picked up by the current stmt's expression. Rather than recreate them, they
141 are simply copied here and then copied into the new expression when it is
142 processed.
144 a_2 = b_5 + 6
145 v_8 = a_2 + c_4
147 a_2's expression 'b_5 + 6' is determined to be replaceable at the use
148 location. It is dependent on the partition 'b_5' is in. This is cached into
149 the NEW_REPLACEABLE_DEPENDENCIES bitmap, and when v_8 is examined for
150 replaceability, it is a candidate, and it is dependent on the partition
151 b_5 is in *NOT* a_2, as well as c_4's partition.
153 if v_8 is also replaceable:
155 x_9 = v_8 * 5
157 x_9 is dependent on partitions b_5, and c_4
159 if a statement is found which has either of those partitions written to
160 before x_9 is used, then x_9 itself is NOT replaceable. */
163 /* Temporary Expression Replacement (TER) table information. */
165 typedef struct temp_expr_table_d
167 var_map map;
168 bitmap *partition_dependencies; /* Partitions expr is dependent on. */
169 bitmap replaceable_expressions; /* Replacement expression table. */
170 bitmap *expr_decl_uids; /* Base uids of exprs. */
171 bitmap *kill_list; /* Expr's killed by a partition. */
172 int virtual_partition; /* Pseudo partition for virtual ops. */
173 bitmap partition_in_use; /* Partitions with kill entries. */
174 bitmap new_replaceable_dependencies; /* Holding place for pending dep's. */
175 int *num_in_part; /* # of ssa_names in a partition. */
176 int *call_cnt; /* Call count at definition. */
177 } *temp_expr_table_p;
179 /* Used to indicate a dependency on VDEFs. */
180 #define VIRTUAL_PARTITION(table) (table->virtual_partition)
182 /* A place for the many, many bitmaps we create. */
183 static bitmap_obstack ter_bitmap_obstack;
185 #ifdef ENABLE_CHECKING
186 extern void debug_ter (FILE *, temp_expr_table_p);
187 #endif
190 /* Create a new TER table for MAP. */
192 static temp_expr_table_p
193 new_temp_expr_table (var_map map)
195 temp_expr_table_p t;
196 unsigned x;
198 t = XNEW (struct temp_expr_table_d);
199 t->map = map;
201 t->partition_dependencies = XCNEWVEC (bitmap, num_ssa_names + 1);
202 t->expr_decl_uids = XCNEWVEC (bitmap, num_ssa_names + 1);
203 t->kill_list = XCNEWVEC (bitmap, num_var_partitions (map) + 1);
205 t->partition_in_use = BITMAP_ALLOC (&ter_bitmap_obstack);
207 t->virtual_partition = num_var_partitions (map);
208 t->new_replaceable_dependencies = BITMAP_ALLOC (&ter_bitmap_obstack);
210 t->replaceable_expressions = NULL;
211 t->num_in_part = XCNEWVEC (int, num_var_partitions (map));
212 for (x = 1; x < num_ssa_names; x++)
214 int p;
215 tree name = ssa_name (x);
216 if (!name)
217 continue;
218 p = var_to_partition (map, name);
219 if (p != NO_PARTITION)
220 t->num_in_part[p]++;
222 t->call_cnt = XCNEWVEC (int, num_ssa_names + 1);
224 return t;
228 /* Free TER table T. If there are valid replacements, return the expression
229 vector. */
231 static bitmap
232 free_temp_expr_table (temp_expr_table_p t)
234 bitmap ret = NULL;
236 #ifdef ENABLE_CHECKING
237 unsigned x;
238 for (x = 0; x <= num_var_partitions (t->map); x++)
239 gcc_assert (!t->kill_list[x]);
240 for (x = 0; x < num_ssa_names; x++)
242 gcc_assert (t->expr_decl_uids[x] == NULL);
243 gcc_assert (t->partition_dependencies[x] == NULL);
245 #endif
247 BITMAP_FREE (t->partition_in_use);
248 BITMAP_FREE (t->new_replaceable_dependencies);
250 free (t->expr_decl_uids);
251 free (t->kill_list);
252 free (t->partition_dependencies);
253 free (t->num_in_part);
254 free (t->call_cnt);
256 if (t->replaceable_expressions)
257 ret = t->replaceable_expressions;
259 free (t);
260 return ret;
264 /* Return TRUE if VERSION is to be replaced by an expression in TAB. */
266 static inline bool
267 version_to_be_replaced_p (temp_expr_table_p tab, int version)
269 if (!tab->replaceable_expressions)
270 return false;
271 return bitmap_bit_p (tab->replaceable_expressions, version);
275 /* Add partition P to the list if partitions VERSION is dependent on. TAB is
276 the expression table */
278 static inline void
279 make_dependent_on_partition (temp_expr_table_p tab, int version, int p)
281 if (!tab->partition_dependencies[version])
282 tab->partition_dependencies[version] = BITMAP_ALLOC (&ter_bitmap_obstack);
284 bitmap_set_bit (tab->partition_dependencies[version], p);
288 /* Add VER to the kill list for P. TAB is the expression table */
290 static inline void
291 add_to_partition_kill_list (temp_expr_table_p tab, int p, int ver)
293 if (!tab->kill_list[p])
295 tab->kill_list[p] = BITMAP_ALLOC (&ter_bitmap_obstack);
296 bitmap_set_bit (tab->partition_in_use, p);
298 bitmap_set_bit (tab->kill_list[p], ver);
302 /* Remove VER from the partition kill list for P. TAB is the expression
303 table. */
305 static inline void
306 remove_from_partition_kill_list (temp_expr_table_p tab, int p, int version)
308 gcc_checking_assert (tab->kill_list[p]);
309 bitmap_clear_bit (tab->kill_list[p], version);
310 if (bitmap_empty_p (tab->kill_list[p]))
312 bitmap_clear_bit (tab->partition_in_use, p);
313 BITMAP_FREE (tab->kill_list[p]);
318 /* Add a dependency between the def of ssa VERSION and VAR. If VAR is
319 replaceable by an expression, add a dependence each of the elements of the
320 expression. These are contained in the new_replaceable list. TAB is the
321 expression table. */
323 static void
324 add_dependence (temp_expr_table_p tab, int version, tree var)
326 int i;
327 bitmap_iterator bi;
328 unsigned x;
330 i = SSA_NAME_VERSION (var);
331 if (version_to_be_replaced_p (tab, i))
333 if (!bitmap_empty_p (tab->new_replaceable_dependencies))
335 /* Version will now be killed by a write to any partition the
336 substituted expression would have been killed by. */
337 EXECUTE_IF_SET_IN_BITMAP (tab->new_replaceable_dependencies, 0, x, bi)
338 add_to_partition_kill_list (tab, x, version);
340 /* Rather than set partition_dependencies and in_use lists bit by
341 bit, simply OR in the new_replaceable_dependencies bits. */
342 if (!tab->partition_dependencies[version])
343 tab->partition_dependencies[version] =
344 BITMAP_ALLOC (&ter_bitmap_obstack);
345 bitmap_ior_into (tab->partition_dependencies[version],
346 tab->new_replaceable_dependencies);
347 bitmap_ior_into (tab->partition_in_use,
348 tab->new_replaceable_dependencies);
349 /* It is only necessary to add these once. */
350 bitmap_clear (tab->new_replaceable_dependencies);
353 else
355 i = var_to_partition (tab->map, var);
356 gcc_checking_assert (i != NO_PARTITION);
357 gcc_checking_assert (tab->num_in_part[i] != 0);
358 /* Only dependencies on ssa_names which are coalesced with something need
359 to be tracked. Partitions with containing only a single SSA_NAME
360 *cannot* have their value changed. */
361 if (tab->num_in_part[i] > 1)
363 add_to_partition_kill_list (tab, i, version);
364 make_dependent_on_partition (tab, version, i);
370 /* This function will remove the expression for VERSION from replacement
371 consideration in table TAB. If FREE_EXPR is true, then remove the
372 expression from consideration as well by freeing the decl uid bitmap. */
374 static void
375 finished_with_expr (temp_expr_table_p tab, int version, bool free_expr)
377 unsigned i;
378 bitmap_iterator bi;
380 /* Remove this expression from its dependent lists. The partition dependence
381 list is retained and transferred later to whomever uses this version. */
382 if (tab->partition_dependencies[version])
384 EXECUTE_IF_SET_IN_BITMAP (tab->partition_dependencies[version], 0, i, bi)
385 remove_from_partition_kill_list (tab, i, version);
386 BITMAP_FREE (tab->partition_dependencies[version]);
388 if (free_expr)
389 BITMAP_FREE (tab->expr_decl_uids[version]);
393 /* Return TRUE if expression STMT is suitable for replacement.
394 In addition to ssa_is_replaceable_p, require the same bb, and for -O0
395 same locus and same BLOCK), Considers memory loads as replaceable if aliasing
396 is available. */
398 static inline bool
399 ter_is_replaceable_p (gimple stmt)
402 if (ssa_is_replaceable_p (stmt))
404 use_operand_p use_p;
405 tree def;
406 gimple use_stmt;
407 location_t locus1, locus2;
408 tree block1, block2;
410 /* Only consider definitions which have a single use. ssa_is_replaceable_p
411 already performed this check, but the use stmt pointer is required for
412 further checks. */
413 def = SINGLE_SSA_TREE_OPERAND (stmt, SSA_OP_DEF);
414 if (!single_imm_use (def, &use_p, &use_stmt))
415 return false;
417 /* If the use isn't in this block, it wont be replaced either. */
418 if (gimple_bb (use_stmt) != gimple_bb (stmt))
419 return false;
421 locus1 = gimple_location (stmt);
422 block1 = LOCATION_BLOCK (locus1);
423 locus1 = LOCATION_LOCUS (locus1);
425 if (gphi *phi = dyn_cast <gphi *> (use_stmt))
426 locus2 = gimple_phi_arg_location (phi,
427 PHI_ARG_INDEX_FROM_USE (use_p));
428 else
429 locus2 = gimple_location (use_stmt);
430 block2 = LOCATION_BLOCK (locus2);
431 locus2 = LOCATION_LOCUS (locus2);
433 if ((!optimize || optimize_debug)
434 && ((locus1 != UNKNOWN_LOCATION && locus1 != locus2)
435 || (block1 != NULL_TREE && block1 != block2)))
436 return false;
438 return true;
440 return false;
444 /* Create an expression entry for a replaceable expression. */
446 static void
447 process_replaceable (temp_expr_table_p tab, gimple stmt, int call_cnt)
449 tree var, def, basevar;
450 int version;
451 ssa_op_iter iter;
452 bitmap def_vars, use_vars;
454 gcc_checking_assert (ter_is_replaceable_p (stmt));
456 def = SINGLE_SSA_TREE_OPERAND (stmt, SSA_OP_DEF);
457 version = SSA_NAME_VERSION (def);
458 def_vars = BITMAP_ALLOC (&ter_bitmap_obstack);
460 basevar = SSA_NAME_VAR (def);
461 if (basevar)
462 bitmap_set_bit (def_vars, DECL_UID (basevar));
464 /* Add this expression to the dependency list for each use partition. */
465 FOR_EACH_SSA_TREE_OPERAND (var, stmt, iter, SSA_OP_USE)
467 int var_version = SSA_NAME_VERSION (var);
469 use_vars = tab->expr_decl_uids[var_version];
470 add_dependence (tab, version, var);
471 if (use_vars)
473 bitmap_ior_into (def_vars, use_vars);
474 BITMAP_FREE (tab->expr_decl_uids[var_version]);
476 else if (SSA_NAME_VAR (var))
477 bitmap_set_bit (def_vars, DECL_UID (SSA_NAME_VAR (var)));
479 tab->expr_decl_uids[version] = def_vars;
481 /* If there are VUSES, add a dependence on virtual defs. */
482 if (gimple_vuse (stmt))
484 make_dependent_on_partition (tab, version, VIRTUAL_PARTITION (tab));
485 add_to_partition_kill_list (tab, VIRTUAL_PARTITION (tab), version);
488 tab->call_cnt[version] = call_cnt;
492 /* This function removes any expression in TAB which is dependent on PARTITION
493 from consideration, making it not replaceable. */
495 static inline void
496 kill_expr (temp_expr_table_p tab, int partition)
498 unsigned version;
500 /* Mark every active expr dependent on this var as not replaceable.
501 finished_with_expr can modify the bitmap, so we can't execute over it. */
502 while (tab->kill_list[partition])
504 version = bitmap_first_set_bit (tab->kill_list[partition]);
505 finished_with_expr (tab, version, true);
508 gcc_checking_assert (!tab->kill_list[partition]);
512 /* This function kills all expressions in TAB which are dependent on virtual
513 partitions. */
515 static inline void
516 kill_virtual_exprs (temp_expr_table_p tab)
518 kill_expr (tab, VIRTUAL_PARTITION (tab));
522 /* Mark the expression associated with VAR as replaceable, and enter
523 the defining stmt into the partition_dependencies table TAB. If
524 MORE_REPLACING is true, accumulate the pending partition dependencies. */
526 static void
527 mark_replaceable (temp_expr_table_p tab, tree var, bool more_replacing)
529 int version = SSA_NAME_VERSION (var);
531 /* Move the dependence list to the pending listpending. */
532 if (more_replacing && tab->partition_dependencies[version])
533 bitmap_ior_into (tab->new_replaceable_dependencies,
534 tab->partition_dependencies[version]);
536 finished_with_expr (tab, version, !more_replacing);
538 /* Set the replaceable expression.
539 The bitmap for this "escapes" from this file so it's allocated
540 on the default obstack. */
541 if (!tab->replaceable_expressions)
542 tab->replaceable_expressions = BITMAP_ALLOC (NULL);
543 bitmap_set_bit (tab->replaceable_expressions, version);
547 /* Helper function for find_ssaname_in_stores. Called via walk_tree to
548 find a SSA_NAME DATA somewhere in *TP. */
550 static tree
551 find_ssaname (tree *tp, int *walk_subtrees, void *data)
553 tree var = (tree) data;
554 if (*tp == var)
555 return var;
556 else if (IS_TYPE_OR_DECL_P (*tp))
557 *walk_subtrees = 0;
558 return NULL_TREE;
561 /* Helper function for find_replaceable_in_bb. Return true if SSA_NAME DATA
562 is used somewhere in T, which is a store in the statement. Called via
563 walk_stmt_load_store_addr_ops. */
565 static bool
566 find_ssaname_in_store (gimple, tree, tree t, void *data)
568 return walk_tree (&t, find_ssaname, data, NULL) != NULL_TREE;
571 /* This function processes basic block BB, and looks for variables which can
572 be replaced by their expressions. Results are stored in the table TAB. */
574 static void
575 find_replaceable_in_bb (temp_expr_table_p tab, basic_block bb)
577 gimple_stmt_iterator bsi;
578 gimple stmt;
579 tree def, use, fndecl;
580 int partition;
581 var_map map = tab->map;
582 ssa_op_iter iter;
583 bool stmt_replaceable;
584 int cur_call_cnt = 0;
586 for (bsi = gsi_start_bb (bb); !gsi_end_p (bsi); gsi_next (&bsi))
588 stmt = gsi_stmt (bsi);
590 if (is_gimple_debug (stmt))
591 continue;
593 stmt_replaceable = ter_is_replaceable_p (stmt);
595 /* Determine if this stmt finishes an existing expression. */
596 FOR_EACH_SSA_TREE_OPERAND (use, stmt, iter, SSA_OP_USE)
598 unsigned ver = SSA_NAME_VERSION (use);
600 /* If this use is a potential replacement variable, process it. */
601 if (tab->expr_decl_uids[ver])
603 bool same_root_var = false;
604 ssa_op_iter iter2;
605 bitmap vars = tab->expr_decl_uids[ver];
607 /* See if the root variables are the same. If they are, we
608 do not want to do the replacement to avoid problems with
609 code size, see PR tree-optimization/17549. */
610 if (!bitmap_empty_p (vars))
611 FOR_EACH_SSA_TREE_OPERAND (def, stmt, iter2, SSA_OP_DEF)
613 if (SSA_NAME_VAR (def)
614 && bitmap_bit_p (vars, DECL_UID (SSA_NAME_VAR (def))))
616 same_root_var = true;
617 break;
621 /* If the stmt does a memory store and the replacement
622 is a load aliasing it avoid creating overlapping
623 assignments which we cannot expand correctly. */
624 if (gimple_vdef (stmt))
626 gimple def_stmt = SSA_NAME_DEF_STMT (use);
627 while (is_gimple_assign (def_stmt)
628 && gimple_assign_rhs_code (def_stmt) == SSA_NAME)
629 def_stmt
630 = SSA_NAME_DEF_STMT (gimple_assign_rhs1 (def_stmt));
631 if (gimple_vuse (def_stmt)
632 && gimple_assign_single_p (def_stmt)
633 && stmt_may_clobber_ref_p (stmt,
634 gimple_assign_rhs1 (def_stmt)))
636 /* For calls, it is not a problem if USE is among
637 call's arguments or say OBJ_TYPE_REF argument,
638 all those necessarily need to be evaluated before
639 the call that may clobber the memory. But if
640 LHS of the call refers to USE, expansion might
641 evaluate it after the call, prevent TER in that
642 case.
643 For inline asm, allow TER of loads into input
644 arguments, but disallow TER for USEs that occur
645 somewhere in outputs. */
646 if (is_gimple_call (stmt)
647 || gimple_code (stmt) == GIMPLE_ASM)
649 if (walk_stmt_load_store_ops (stmt, use, NULL,
650 find_ssaname_in_store))
651 same_root_var = true;
653 else
654 same_root_var = true;
658 /* Mark expression as replaceable unless stmt is volatile, or the
659 def variable has the same root variable as something in the
660 substitution list, or the def and use span a call such that
661 we'll expand lifetimes across a call. */
662 if (gimple_has_volatile_ops (stmt) || same_root_var
663 || (tab->call_cnt[ver] != cur_call_cnt
664 && SINGLE_SSA_USE_OPERAND (SSA_NAME_DEF_STMT (use), SSA_OP_USE)
665 == NULL_USE_OPERAND_P))
666 finished_with_expr (tab, ver, true);
667 else
668 mark_replaceable (tab, use, stmt_replaceable);
672 /* Next, see if this stmt kills off an active expression. */
673 FOR_EACH_SSA_TREE_OPERAND (def, stmt, iter, SSA_OP_DEF)
675 partition = var_to_partition (map, def);
676 if (partition != NO_PARTITION && tab->kill_list[partition])
677 kill_expr (tab, partition);
680 /* Increment counter if this is a non BUILT_IN call. We allow
681 replacement over BUILT_IN calls since many will expand to inline
682 insns instead of a true call. */
683 if (is_gimple_call (stmt)
684 && !((fndecl = gimple_call_fndecl (stmt))
685 && DECL_BUILT_IN (fndecl)))
686 cur_call_cnt++;
688 /* Now see if we are creating a new expression or not. */
689 if (stmt_replaceable)
690 process_replaceable (tab, stmt, cur_call_cnt);
692 /* Free any unused dependency lists. */
693 bitmap_clear (tab->new_replaceable_dependencies);
695 /* A V_{MAY,MUST}_DEF kills any expression using a virtual operand,
696 including the current stmt. */
697 if (gimple_vdef (stmt))
698 kill_virtual_exprs (tab);
703 /* This function is the driver routine for replacement of temporary expressions
704 in the SSA->normal phase, operating on MAP. If there are replaceable
705 expressions, a table is returned which maps SSA versions to the
706 expressions they should be replaced with. A NULL_TREE indicates no
707 replacement should take place. If there are no replacements at all,
708 NULL is returned by the function, otherwise an expression vector indexed
709 by SSA_NAME version numbers. */
711 bitmap
712 find_replaceable_exprs (var_map map)
714 basic_block bb;
715 temp_expr_table_p table;
716 bitmap ret;
718 bitmap_obstack_initialize (&ter_bitmap_obstack);
719 table = new_temp_expr_table (map);
720 FOR_EACH_BB_FN (bb, cfun)
722 find_replaceable_in_bb (table, bb);
723 gcc_checking_assert (bitmap_empty_p (table->partition_in_use));
725 ret = free_temp_expr_table (table);
726 bitmap_obstack_release (&ter_bitmap_obstack);
727 return ret;
730 /* Dump TER expression table EXPR to file F. */
732 void
733 dump_replaceable_exprs (FILE *f, bitmap expr)
735 tree var;
736 unsigned x;
738 fprintf (f, "\nReplacing Expressions\n");
739 for (x = 0; x < num_ssa_names; x++)
740 if (bitmap_bit_p (expr, x))
742 var = ssa_name (x);
743 print_generic_expr (f, var, TDF_SLIM);
744 fprintf (f, " replace with --> ");
745 print_gimple_stmt (f, SSA_NAME_DEF_STMT (var), 0, TDF_SLIM);
746 fprintf (f, "\n");
748 fprintf (f, "\n");
752 #ifdef ENABLE_CHECKING
753 /* Dump the status of the various tables in the expression table. This is used
754 exclusively to debug TER. F is the place to send debug info and T is the
755 table being debugged. */
757 DEBUG_FUNCTION void
758 debug_ter (FILE *f, temp_expr_table_p t)
760 unsigned x, y;
761 bitmap_iterator bi;
763 fprintf (f, "\nDumping current state of TER\n virtual partition = %d\n",
764 VIRTUAL_PARTITION (t));
765 if (t->replaceable_expressions)
766 dump_replaceable_exprs (f, t->replaceable_expressions);
767 fprintf (f, "Currently tracking the following expressions:\n");
769 for (x = 1; x < num_ssa_names; x++)
770 if (t->expr_decl_uids[x])
772 print_generic_expr (f, ssa_name (x), TDF_SLIM);
773 fprintf (f, " dep-parts : ");
774 if (t->partition_dependencies[x]
775 && !bitmap_empty_p (t->partition_dependencies[x]))
777 EXECUTE_IF_SET_IN_BITMAP (t->partition_dependencies[x], 0, y, bi)
778 fprintf (f, "P%d ",y);
780 fprintf (f, " basedecls: ");
781 EXECUTE_IF_SET_IN_BITMAP (t->expr_decl_uids[x], 0, y, bi)
782 fprintf (f, "%d ",y);
783 fprintf (f, " call_cnt : %d",t->call_cnt[x]);
784 fprintf (f, "\n");
787 bitmap_print (f, t->partition_in_use, "Partitions in use ",
788 "\npartition KILL lists:\n");
790 for (x = 0; x <= num_var_partitions (t->map); x++)
791 if (t->kill_list[x])
793 fprintf (f, "Partition %d : ", x);
794 EXECUTE_IF_SET_IN_BITMAP (t->kill_list[x], 0, y, bi)
795 fprintf (f, "_%d ",y);
798 fprintf (f, "\n----------\n");
800 #endif