1 /* Convert a program in SSA form into Normal form.
2 Copyright (C) 2004, 2005 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 2, or (at your option)
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 COPYING. If not, write to
19 the Free Software Foundation, 59 Temple Place - Suite 330,
20 Boston, MA 02111-1307, USA. */
24 #include "coretypes.h"
31 #include "langhooks.h"
32 #include "hard-reg-set.h"
33 #include "basic-block.h"
38 #include "diagnostic.h"
40 #include "tree-flow.h"
41 #include "tree-gimple.h"
42 #include "tree-inline.h"
46 #include "tree-dump.h"
47 #include "tree-ssa-live.h"
48 #include "tree-pass.h"
50 /* Flags to pass to remove_ssa_form. */
52 #define SSANORM_PERFORM_TER 0x1
53 #define SSANORM_COMBINE_TEMPS 0x2
54 #define SSANORM_REMOVE_ALL_PHIS 0x4
55 #define SSANORM_COALESCE_PARTITIONS 0x8
56 #define SSANORM_USE_COALESCE_LIST 0x10
58 /* Used to hold all the components required to do SSA PHI elimination.
59 The node and pred/succ list is a simple linear list of nodes and
60 edges represented as pairs of nodes.
62 The predecessor and successor list: Nodes are entered in pairs, where
63 [0] ->PRED, [1]->SUCC. All the even indexes in the array represent
64 predecessors, all the odd elements are successors.
67 When implemented as bitmaps, very large programs SSA->Normal times were
68 being dominated by clearing the interference graph.
70 Typically this list of edges is extremely small since it only includes
71 PHI results and uses from a single edge which have not coalesced with
72 each other. This means that no virtual PHI nodes are included, and
73 empirical evidence suggests that the number of edges rarely exceed
74 3, and in a bootstrap of GCC, the maximum size encountered was 7.
75 This also limits the number of possible nodes that are involved to
76 rarely more than 6, and in the bootstrap of gcc, the maximum number
77 of nodes encountered was 12. */
79 typedef struct _elim_graph {
80 /* Size of the elimination vectors. */
83 /* List of nodes in the elimination graph. */
86 /* The predecessor and successor edge list. */
87 varray_type edge_list;
92 /* Stack for visited nodes. */
95 /* The variable partition map. */
98 /* Edge being eliminated by this graph. */
101 /* List of constant copies to emit. These are pushed on in pairs. */
102 varray_type const_copies;
106 /* Local functions. */
107 static tree create_temp (tree);
108 static void insert_copy_on_edge (edge, tree, tree);
109 static elim_graph new_elim_graph (int);
110 static inline void delete_elim_graph (elim_graph);
111 static inline void clear_elim_graph (elim_graph);
112 static inline int elim_graph_size (elim_graph);
113 static inline void elim_graph_add_node (elim_graph, tree);
114 static inline void elim_graph_add_edge (elim_graph, int, int);
115 static inline int elim_graph_remove_succ_edge (elim_graph, int);
117 static inline void eliminate_name (elim_graph, tree);
118 static void eliminate_build (elim_graph, basic_block);
119 static void elim_forward (elim_graph, int);
120 static int elim_unvisited_predecessor (elim_graph, int);
121 static void elim_backward (elim_graph, int);
122 static void elim_create (elim_graph, int);
123 static void eliminate_phi (edge, elim_graph);
124 static tree_live_info_p coalesce_ssa_name (var_map, int);
125 static void assign_vars (var_map);
126 static bool replace_use_variable (var_map, use_operand_p, tree *);
127 static bool replace_def_variable (var_map, def_operand_p, tree *);
128 static void eliminate_virtual_phis (void);
129 static void coalesce_abnormal_edges (var_map, conflict_graph, root_var_p);
130 static void print_exprs (FILE *, const char *, tree, const char *, tree,
132 static void print_exprs_edge (FILE *, edge, const char *, tree, const char *,
136 /* Create a temporary variable based on the type of variable T. Use T's name
143 const char *name = NULL;
146 if (TREE_CODE (t) == SSA_NAME)
147 t = SSA_NAME_VAR (t);
149 gcc_assert (TREE_CODE (t) == VAR_DECL || TREE_CODE (t) == PARM_DECL);
151 type = TREE_TYPE (t);
154 name = IDENTIFIER_POINTER (tmp);
158 tmp = create_tmp_var (type, name);
160 if (DECL_DEBUG_ALIAS_OF (t))
161 DECL_DEBUG_ALIAS_OF (tmp) = DECL_DEBUG_ALIAS_OF (t);
162 else if (!DECL_IGNORED_P (t))
163 DECL_DEBUG_ALIAS_OF (tmp) = t;
164 DECL_ARTIFICIAL (tmp) = DECL_ARTIFICIAL (t);
165 DECL_IGNORED_P (tmp) = DECL_IGNORED_P (t);
166 add_referenced_tmp_var (tmp);
168 /* add_referenced_tmp_var will create the annotation and set up some
169 of the flags in the annotation. However, some flags we need to
170 inherit from our original variable. */
171 var_ann (tmp)->type_mem_tag = var_ann (t)->type_mem_tag;
172 if (is_call_clobbered (t))
173 mark_call_clobbered (tmp);
179 /* This helper function fill insert a copy from a constant or variable SRC to
180 variable DEST on edge E. */
183 insert_copy_on_edge (edge e, tree dest, tree src)
187 copy = build (MODIFY_EXPR, TREE_TYPE (dest), dest, src);
190 if (TREE_CODE (src) == ADDR_EXPR)
191 src = TREE_OPERAND (src, 0);
192 if (TREE_CODE (src) == VAR_DECL || TREE_CODE (src) == PARM_DECL)
195 if (dump_file && (dump_flags & TDF_DETAILS))
198 "Inserting a copy on edge BB%d->BB%d :",
201 print_generic_expr (dump_file, copy, dump_flags);
202 fprintf (dump_file, "\n");
205 bsi_insert_on_edge (e, copy);
209 /* Create an elimination graph with SIZE nodes and associated data
213 new_elim_graph (int size)
215 elim_graph g = (elim_graph) xmalloc (sizeof (struct _elim_graph));
217 VARRAY_TREE_INIT (g->nodes, 30, "Elimination Node List");
218 VARRAY_TREE_INIT (g->const_copies, 20, "Elimination Constant Copies");
219 VARRAY_INT_INIT (g->edge_list, 20, "Elimination Edge List");
220 VARRAY_INT_INIT (g->stack, 30, " Elimination Stack");
222 g->visited = sbitmap_alloc (size);
228 /* Empty elimination graph G. */
231 clear_elim_graph (elim_graph g)
233 VARRAY_POP_ALL (g->nodes);
234 VARRAY_POP_ALL (g->edge_list);
238 /* Delete elimination graph G. */
241 delete_elim_graph (elim_graph g)
243 sbitmap_free (g->visited);
248 /* Return the number of nodes in graph G. */
251 elim_graph_size (elim_graph g)
253 return VARRAY_ACTIVE_SIZE (g->nodes);
257 /* Add NODE to graph G, if it doesn't exist already. */
260 elim_graph_add_node (elim_graph g, tree node)
263 for (x = 0; x < elim_graph_size (g); x++)
264 if (VARRAY_TREE (g->nodes, x) == node)
266 VARRAY_PUSH_TREE (g->nodes, node);
270 /* Add the edge PRED->SUCC to graph G. */
273 elim_graph_add_edge (elim_graph g, int pred, int succ)
275 VARRAY_PUSH_INT (g->edge_list, pred);
276 VARRAY_PUSH_INT (g->edge_list, succ);
280 /* Remove an edge from graph G for which NODE is the predecessor, and
281 return the successor node. -1 is returned if there is no such edge. */
284 elim_graph_remove_succ_edge (elim_graph g, int node)
288 for (x = 0; x < VARRAY_ACTIVE_SIZE (g->edge_list); x += 2)
289 if (VARRAY_INT (g->edge_list, x) == node)
291 VARRAY_INT (g->edge_list, x) = -1;
292 y = VARRAY_INT (g->edge_list, x + 1);
293 VARRAY_INT (g->edge_list, x + 1) = -1;
300 /* Find all the nodes in GRAPH which are successors to NODE in the
301 edge list. VAR will hold the partition number found. CODE is the
302 code fragment executed for every node found. */
304 #define FOR_EACH_ELIM_GRAPH_SUCC(GRAPH, NODE, VAR, CODE) \
308 for (x_ = 0; x_ < VARRAY_ACTIVE_SIZE ((GRAPH)->edge_list); x_ += 2) \
310 y_ = VARRAY_INT ((GRAPH)->edge_list, x_); \
313 (VAR) = VARRAY_INT ((GRAPH)->edge_list, x_ + 1); \
319 /* Find all the nodes which are predecessors of NODE in the edge list for
320 GRAPH. VAR will hold the partition number found. CODE is the
321 code fragment executed for every node found. */
323 #define FOR_EACH_ELIM_GRAPH_PRED(GRAPH, NODE, VAR, CODE) \
327 for (x_ = 0; x_ < VARRAY_ACTIVE_SIZE ((GRAPH)->edge_list); x_ += 2) \
329 y_ = VARRAY_INT ((GRAPH)->edge_list, x_ + 1); \
332 (VAR) = VARRAY_INT ((GRAPH)->edge_list, x_); \
338 /* Add T to elimination graph G. */
341 eliminate_name (elim_graph g, tree T)
343 elim_graph_add_node (g, T);
347 /* Build elimination graph G for basic block BB on incoming PHI edge
351 eliminate_build (elim_graph g, basic_block B)
357 clear_elim_graph (g);
359 for (phi = phi_nodes (B); phi; phi = PHI_CHAIN (phi))
361 T0 = var_to_partition_to_var (g->map, PHI_RESULT (phi));
363 /* Ignore results which are not in partitions. */
367 Ti = PHI_ARG_DEF (phi, g->e->dest_idx);
369 /* If this argument is a constant, or a SSA_NAME which is being
370 left in SSA form, just queue a copy to be emitted on this
372 if (!phi_ssa_name_p (Ti)
373 || (TREE_CODE (Ti) == SSA_NAME
374 && var_to_partition (g->map, Ti) == NO_PARTITION))
376 /* Save constant copies until all other copies have been emitted
378 VARRAY_PUSH_TREE (g->const_copies, T0);
379 VARRAY_PUSH_TREE (g->const_copies, Ti);
383 Ti = var_to_partition_to_var (g->map, Ti);
386 eliminate_name (g, T0);
387 eliminate_name (g, Ti);
388 p0 = var_to_partition (g->map, T0);
389 pi = var_to_partition (g->map, Ti);
390 elim_graph_add_edge (g, p0, pi);
397 /* Push successors of T onto the elimination stack for G. */
400 elim_forward (elim_graph g, int T)
403 SET_BIT (g->visited, T);
404 FOR_EACH_ELIM_GRAPH_SUCC (g, T, S,
406 if (!TEST_BIT (g->visited, S))
409 VARRAY_PUSH_INT (g->stack, T);
413 /* Return 1 if there unvisited predecessors of T in graph G. */
416 elim_unvisited_predecessor (elim_graph g, int T)
419 FOR_EACH_ELIM_GRAPH_PRED (g, T, P,
421 if (!TEST_BIT (g->visited, P))
427 /* Process predecessors first, and insert a copy. */
430 elim_backward (elim_graph g, int T)
433 SET_BIT (g->visited, T);
434 FOR_EACH_ELIM_GRAPH_PRED (g, T, P,
436 if (!TEST_BIT (g->visited, P))
438 elim_backward (g, P);
439 insert_copy_on_edge (g->e,
440 partition_to_var (g->map, P),
441 partition_to_var (g->map, T));
446 /* Insert required copies for T in graph G. Check for a strongly connected
447 region, and create a temporary to break the cycle if one is found. */
450 elim_create (elim_graph g, int T)
455 if (elim_unvisited_predecessor (g, T))
457 U = create_temp (partition_to_var (g->map, T));
458 insert_copy_on_edge (g->e, U, partition_to_var (g->map, T));
459 FOR_EACH_ELIM_GRAPH_PRED (g, T, P,
461 if (!TEST_BIT (g->visited, P))
463 elim_backward (g, P);
464 insert_copy_on_edge (g->e, partition_to_var (g->map, P), U);
470 S = elim_graph_remove_succ_edge (g, T);
473 SET_BIT (g->visited, T);
474 insert_copy_on_edge (g->e,
475 partition_to_var (g->map, T),
476 partition_to_var (g->map, S));
482 /* Eliminate all the phi nodes on edge E in graph G. */
485 eliminate_phi (edge e, elim_graph g)
489 basic_block B = e->dest;
491 gcc_assert (VARRAY_ACTIVE_SIZE (g->const_copies) == 0);
493 /* Abnormal edges already have everything coalesced, or the coalescer
494 would have aborted. */
495 if (e->flags & EDGE_ABNORMAL)
498 num_nodes = num_var_partitions (g->map);
501 eliminate_build (g, B);
503 if (elim_graph_size (g) != 0)
505 sbitmap_zero (g->visited);
506 VARRAY_POP_ALL (g->stack);
508 for (x = 0; x < elim_graph_size (g); x++)
510 tree var = VARRAY_TREE (g->nodes, x);
511 int p = var_to_partition (g->map, var);
512 if (!TEST_BIT (g->visited, p))
516 sbitmap_zero (g->visited);
517 while (VARRAY_ACTIVE_SIZE (g->stack) > 0)
519 x = VARRAY_TOP_INT (g->stack);
520 VARRAY_POP (g->stack);
521 if (!TEST_BIT (g->visited, x))
526 /* If there are any pending constant copies, issue them now. */
527 while (VARRAY_ACTIVE_SIZE (g->const_copies) > 0)
530 src = VARRAY_TOP_TREE (g->const_copies);
531 VARRAY_POP (g->const_copies);
532 dest = VARRAY_TOP_TREE (g->const_copies);
533 VARRAY_POP (g->const_copies);
534 insert_copy_on_edge (e, dest, src);
539 /* Shortcut routine to print messages to file F of the form:
540 "STR1 EXPR1 STR2 EXPR2 STR3." */
543 print_exprs (FILE *f, const char *str1, tree expr1, const char *str2,
544 tree expr2, const char *str3)
546 fprintf (f, "%s", str1);
547 print_generic_expr (f, expr1, TDF_SLIM);
548 fprintf (f, "%s", str2);
549 print_generic_expr (f, expr2, TDF_SLIM);
550 fprintf (f, "%s", str3);
554 /* Shortcut routine to print abnormal edge messages to file F of the form:
555 "STR1 EXPR1 STR2 EXPR2 across edge E. */
558 print_exprs_edge (FILE *f, edge e, const char *str1, tree expr1,
559 const char *str2, tree expr2)
561 print_exprs (f, str1, expr1, str2, expr2, " across an abnormal edge");
562 fprintf (f, " from BB%d->BB%d\n", e->src->index,
567 /* Coalesce partitions in MAP which are live across abnormal edges in GRAPH.
568 RV is the root variable groupings of the partitions in MAP. Since code
569 cannot be inserted on these edges, failure to coalesce something across
570 an abnormal edge is an error. */
573 coalesce_abnormal_edges (var_map map, conflict_graph graph, root_var_p rv)
581 /* Code cannot be inserted on abnormal edges. Look for all abnormal
582 edges, and coalesce any PHI results with their arguments across
586 FOR_EACH_EDGE (e, ei, bb->succs)
587 if (e->dest != EXIT_BLOCK_PTR && e->flags & EDGE_ABNORMAL)
588 for (phi = phi_nodes (e->dest); phi; phi = PHI_CHAIN (phi))
590 /* Visit each PHI on the destination side of this abnormal
591 edge, and attempt to coalesce the argument with the result. */
592 var = PHI_RESULT (phi);
593 x = var_to_partition (map, var);
595 /* Ignore results which are not relevant. */
596 if (x == NO_PARTITION)
599 tmp = PHI_ARG_DEF (phi, e->dest_idx);
600 #ifdef ENABLE_CHECKING
601 if (!phi_ssa_name_p (tmp))
603 print_exprs_edge (stderr, e,
604 "\nConstant argument in PHI. Can't insert :",
606 internal_error ("SSA corruption");
609 gcc_assert (phi_ssa_name_p (tmp));
611 y = var_to_partition (map, tmp);
612 gcc_assert (x != NO_PARTITION);
613 gcc_assert (y != NO_PARTITION);
614 #ifdef ENABLE_CHECKING
615 if (root_var_find (rv, x) != root_var_find (rv, y))
617 print_exprs_edge (stderr, e, "\nDifferent root vars: ",
618 root_var (rv, root_var_find (rv, x)),
620 root_var (rv, root_var_find (rv, y)));
621 internal_error ("SSA corruption");
624 gcc_assert (root_var_find (rv, x) == root_var_find (rv, y));
629 #ifdef ENABLE_CHECKING
630 if (conflict_graph_conflict_p (graph, x, y))
632 print_exprs_edge (stderr, e, "\n Conflict ",
633 partition_to_var (map, x),
634 " and ", partition_to_var (map, y));
635 internal_error ("SSA corruption");
638 gcc_assert (!conflict_graph_conflict_p (graph, x, y));
641 /* Now map the partitions back to their real variables. */
642 var = partition_to_var (map, x);
643 tmp = partition_to_var (map, y);
644 if (dump_file && (dump_flags & TDF_DETAILS))
646 print_exprs_edge (dump_file, e,
647 "ABNORMAL: Coalescing ",
650 z = var_union (map, var, tmp);
651 #ifdef ENABLE_CHECKING
652 if (z == NO_PARTITION)
654 print_exprs_edge (stderr, e, "\nUnable to coalesce",
655 partition_to_var (map, x), " and ",
656 partition_to_var (map, y));
657 internal_error ("SSA corruption");
660 gcc_assert (z != NO_PARTITION);
662 gcc_assert (z == x || z == y);
664 conflict_graph_merge_regs (graph, x, y);
666 conflict_graph_merge_regs (graph, y, x);
672 /* Reduce the number of live ranges in MAP. Live range information is
673 returned if FLAGS indicates that we are combining temporaries, otherwise
674 NULL is returned. The only partitions which are associated with actual
675 variables at this point are those which are forced to be coalesced for
676 various reason. (live on entry, live across abnormal edges, etc.). */
678 static tree_live_info_p
679 coalesce_ssa_name (var_map map, int flags)
685 tree_live_info_p liveinfo;
687 conflict_graph graph;
689 coalesce_list_p cl = NULL;
691 if (num_var_partitions (map) <= 1)
694 /* If no preference given, use cheap coalescing of all partitions. */
695 if ((flags & (SSANORM_COALESCE_PARTITIONS | SSANORM_USE_COALESCE_LIST)) == 0)
696 flags |= SSANORM_COALESCE_PARTITIONS;
698 liveinfo = calculate_live_on_entry (map);
699 calculate_live_on_exit (liveinfo);
700 rv = root_var_init (map);
702 /* Remove single element variable from the list. */
703 root_var_compact (rv);
705 if (flags & SSANORM_USE_COALESCE_LIST)
707 cl = create_coalesce_list (map);
709 /* Add all potential copies via PHI arguments to the list. */
712 for (phi = phi_nodes (bb); phi; phi = PHI_CHAIN (phi))
714 tree res = PHI_RESULT (phi);
715 int p = var_to_partition (map, res);
716 if (p == NO_PARTITION)
718 for (x = 0; x < (unsigned)PHI_NUM_ARGS (phi); x++)
720 tree arg = PHI_ARG_DEF (phi, x);
723 if (TREE_CODE (arg) != SSA_NAME)
725 if (SSA_NAME_VAR (res) != SSA_NAME_VAR (arg))
727 p2 = var_to_partition (map, PHI_ARG_DEF (phi, x));
728 if (p2 != NO_PARTITION)
729 add_coalesce (cl, p, p2, 1);
734 /* Coalesce all the result decls together. */
737 for (x = 0; x < num_var_partitions (map); x++)
739 tree p = partition_to_var (map, x);
740 if (TREE_CODE (SSA_NAME_VAR(p)) == RESULT_DECL)
742 if (var == NULL_TREE)
748 add_coalesce (cl, i, x, 1);
753 /* Build a conflict graph. */
754 graph = build_tree_conflict_graph (liveinfo, rv, cl);
758 if (dump_file && (dump_flags & TDF_DETAILS))
760 fprintf (dump_file, "Before sorting:\n");
761 dump_coalesce_list (dump_file, cl);
764 sort_coalesce_list (cl);
766 if (dump_file && (dump_flags & TDF_DETAILS))
768 fprintf (dump_file, "\nAfter sorting:\n");
769 dump_coalesce_list (dump_file, cl);
773 /* Put the single element variables back in. */
774 root_var_decompact (rv);
776 /* First, coalesce all live on entry variables to their root variable.
777 This will ensure the first use is coming from the correct location. */
779 live = sbitmap_alloc (num_var_partitions (map));
782 /* Set 'live' vector to indicate live on entry partitions. */
783 num = num_var_partitions (map);
784 for (x = 0 ; x < num; x++)
786 var = partition_to_var (map, x);
787 if (default_def (SSA_NAME_VAR (var)) == var)
791 if ((flags & SSANORM_COMBINE_TEMPS) == 0)
793 delete_tree_live_info (liveinfo);
797 /* Assign root variable as partition representative for each live on entry
799 EXECUTE_IF_SET_IN_SBITMAP (live, 0, x,
801 var = root_var (rv, root_var_find (rv, x));
803 /* If these aren't already coalesced... */
804 if (partition_to_var (map, x) != var)
806 /* This root variable should have not already been assigned
807 to another partition which is not coalesced with this one. */
808 gcc_assert (!ann->out_of_ssa_tag);
810 if (dump_file && (dump_flags & TDF_DETAILS))
812 print_exprs (dump_file, "Must coalesce ",
813 partition_to_var (map, x),
814 " with the root variable ", var, ".\n");
817 change_partition_var (map, var, x);
823 /* Coalesce partitions live across abnormal edges. */
824 coalesce_abnormal_edges (map, graph, rv);
826 if (dump_file && (dump_flags & TDF_DETAILS))
827 dump_var_map (dump_file, map);
829 /* Coalesce partitions. */
830 if (flags & SSANORM_USE_COALESCE_LIST)
831 coalesce_tpa_members (rv, graph, map, cl,
832 ((dump_flags & TDF_DETAILS) ? dump_file
836 if (flags & SSANORM_COALESCE_PARTITIONS)
837 coalesce_tpa_members (rv, graph, map, NULL,
838 ((dump_flags & TDF_DETAILS) ? dump_file
841 delete_coalesce_list (cl);
842 root_var_delete (rv);
843 conflict_graph_delete (graph);
849 /* Take the ssa-name var_map MAP, and assign real variables to each
853 assign_vars (var_map map)
860 rv = root_var_init (map);
864 /* Coalescing may already have forced some partitions to their root
865 variable. Find these and tag them. */
867 num = num_var_partitions (map);
868 for (x = 0; x < num; x++)
870 var = partition_to_var (map, x);
871 if (TREE_CODE (var) != SSA_NAME)
873 /* Coalescing will already have verified that more than one
874 partition doesn't have the same root variable. Simply marked
875 the variable as assigned. */
877 ann->out_of_ssa_tag = 1;
878 if (dump_file && (dump_flags & TDF_DETAILS))
880 fprintf (dump_file, "partition %d has variable ", x);
881 print_generic_expr (dump_file, var, TDF_SLIM);
882 fprintf (dump_file, " assigned to it.\n");
888 num = root_var_num (rv);
889 for (x = 0; x < num; x++)
891 var = root_var (rv, x);
893 for (i = root_var_first_partition (rv, x);
895 i = root_var_next_partition (rv, i))
897 t = partition_to_var (map, i);
899 if (t == var || TREE_CODE (t) != SSA_NAME)
902 rep = var_to_partition (map, t);
904 if (!ann->out_of_ssa_tag)
906 if (dump_file && (dump_flags & TDF_DETAILS))
907 print_exprs (dump_file, "", t, " --> ", var, "\n");
908 change_partition_var (map, var, rep);
912 if (dump_file && (dump_flags & TDF_DETAILS))
913 print_exprs (dump_file, "", t, " not coalesced with ", var,
916 var = create_temp (t);
917 change_partition_var (map, var, rep);
920 if (dump_file && (dump_flags & TDF_DETAILS))
922 fprintf (dump_file, " --> New temp: '");
923 print_generic_expr (dump_file, var, TDF_SLIM);
924 fprintf (dump_file, "'\n");
929 root_var_delete (rv);
933 /* Replace use operand P with whatever variable it has been rewritten to based
934 on the partitions in MAP. EXPR is an optional expression vector over SSA
935 versions which is used to replace P with an expression instead of a variable.
936 If the stmt is changed, return true. */
939 replace_use_variable (var_map map, use_operand_p p, tree *expr)
942 tree var = USE_FROM_PTR (p);
944 /* Check if we are replacing this variable with an expression. */
947 int version = SSA_NAME_VERSION (var);
950 tree new_expr = TREE_OPERAND (expr[version], 1);
951 SET_USE (p, new_expr);
952 /* Clear the stmt's RHS, or GC might bite us. */
953 TREE_OPERAND (expr[version], 1) = NULL_TREE;
958 new_var = var_to_partition_to_var (map, var);
961 SET_USE (p, new_var);
962 set_is_used (new_var);
969 /* Replace def operand DEF_P with whatever variable it has been rewritten to
970 based on the partitions in MAP. EXPR is an optional expression vector over
971 SSA versions which is used to replace DEF_P with an expression instead of a
972 variable. If the stmt is changed, return true. */
975 replace_def_variable (var_map map, def_operand_p def_p, tree *expr)
978 tree var = DEF_FROM_PTR (def_p);
980 /* Check if we are replacing this variable with an expression. */
983 int version = SSA_NAME_VERSION (var);
986 tree new_expr = TREE_OPERAND (expr[version], 1);
987 SET_DEF (def_p, new_expr);
988 /* Clear the stmt's RHS, or GC might bite us. */
989 TREE_OPERAND (expr[version], 1) = NULL_TREE;
994 new_var = var_to_partition_to_var (map, var);
997 SET_DEF (def_p, new_var);
998 set_is_used (new_var);
1005 /* Remove any PHI node which is a virtual PHI. */
1008 eliminate_virtual_phis (void)
1015 for (phi = phi_nodes (bb); phi; phi = next)
1017 next = PHI_CHAIN (phi);
1018 if (!is_gimple_reg (SSA_NAME_VAR (PHI_RESULT (phi))))
1020 #ifdef ENABLE_CHECKING
1022 /* There should be no arguments of this PHI which are in
1023 the partition list, or we get incorrect results. */
1024 for (i = 0; i < PHI_NUM_ARGS (phi); i++)
1026 tree arg = PHI_ARG_DEF (phi, i);
1027 if (TREE_CODE (arg) == SSA_NAME
1028 && is_gimple_reg (SSA_NAME_VAR (arg)))
1030 fprintf (stderr, "Argument of PHI is not virtual (");
1031 print_generic_expr (stderr, arg, TDF_SLIM);
1032 fprintf (stderr, "), but the result is :");
1033 print_generic_stmt (stderr, phi, TDF_SLIM);
1034 internal_error ("SSA corruption");
1038 remove_phi_node (phi, NULL_TREE, bb);
1045 /* This routine will coalesce variables in MAP of the same type which do not
1046 interfere with each other. LIVEINFO is the live range info for variables
1047 of interest. This will both reduce the memory footprint of the stack, and
1048 allow us to coalesce together local copies of globals and scalarized
1052 coalesce_vars (var_map map, tree_live_info_p liveinfo)
1059 conflict_graph graph;
1061 cl = create_coalesce_list (map);
1063 /* Merge all the live on entry vectors for coalesced partitions. */
1064 for (x = 0; x < num_var_partitions (map); x++)
1066 var = partition_to_var (map, x);
1067 p = var_to_partition (map, var);
1069 live_merge_and_clear (liveinfo, p, x);
1072 /* When PHI nodes are turned into copies, the result of each PHI node
1073 becomes live on entry to the block. Mark these now. */
1079 for (phi = phi_nodes (bb); phi; phi = PHI_CHAIN (phi))
1081 p = var_to_partition (map, PHI_RESULT (phi));
1083 /* Skip virtual PHI nodes. */
1084 if (p == (unsigned)NO_PARTITION)
1087 make_live_on_entry (liveinfo, bb, p);
1089 /* Each argument is a potential copy operation. Add any arguments
1090 which are not coalesced to the result to the coalesce list. */
1091 for (x = 0; x < (unsigned)PHI_NUM_ARGS (phi); x++)
1093 arg = PHI_ARG_DEF (phi, x);
1094 if (!phi_ssa_name_p (arg))
1096 p2 = var_to_partition (map, arg);
1097 if (p2 == (unsigned)NO_PARTITION)
1100 add_coalesce (cl, p, p2, 1);
1106 /* Re-calculate live on exit info. */
1107 calculate_live_on_exit (liveinfo);
1109 if (dump_file && (dump_flags & TDF_DETAILS))
1111 fprintf (dump_file, "Live range info for variable memory coalescing.\n");
1112 dump_live_info (dump_file, liveinfo, LIVEDUMP_ALL);
1114 fprintf (dump_file, "Coalesce list from phi nodes:\n");
1115 dump_coalesce_list (dump_file, cl);
1119 tv = type_var_init (map);
1121 type_var_dump (dump_file, tv);
1122 type_var_compact (tv);
1124 type_var_dump (dump_file, tv);
1126 graph = build_tree_conflict_graph (liveinfo, tv, cl);
1128 type_var_decompact (tv);
1129 if (dump_file && (dump_flags & TDF_DETAILS))
1131 fprintf (dump_file, "type var list now looks like:n");
1132 type_var_dump (dump_file, tv);
1134 fprintf (dump_file, "Coalesce list after conflict graph build:\n");
1135 dump_coalesce_list (dump_file, cl);
1138 sort_coalesce_list (cl);
1139 if (dump_file && (dump_flags & TDF_DETAILS))
1141 fprintf (dump_file, "Coalesce list after sorting:\n");
1142 dump_coalesce_list (dump_file, cl);
1145 coalesce_tpa_members (tv, graph, map, cl,
1146 ((dump_flags & TDF_DETAILS) ? dump_file : NULL));
1148 type_var_delete (tv);
1149 delete_coalesce_list (cl);
1153 /* Temporary Expression Replacement (TER)
1155 Replace SSA version variables during out-of-ssa with their defining
1156 expression if there is only one use of the variable.
1158 A pass is made through the function, one block at a time. No cross block
1159 information is tracked.
1161 Variables which only have one use, and whose defining stmt is considered
1162 a replaceable expression (see check_replaceable) are entered into
1163 consideration by adding a list of dependent partitions to the version_info
1164 vector for that ssa_name_version. This information comes from the partition
1165 mapping for each USE. At the same time, the partition_dep_list vector for
1166 these partitions have this version number entered into their lists.
1168 When the use of a replaceable ssa_variable is encountered, the dependence
1169 list in version_info[] is moved to the "pending_dependence" list in case
1170 the current expression is also replaceable. (To be determined later in
1171 processing this stmt.) version_info[] for the version is then updated to
1172 point to the defining stmt and the 'replaceable' bit is set.
1174 Any partition which is defined by a statement 'kills' any expression which
1175 is dependent on this partition. Every ssa version in the partitions'
1176 dependence list is removed from future consideration.
1178 All virtual references are lumped together. Any expression which is
1179 dependent on any virtual variable (via a VUSE) has a dependence added
1180 to the special partition defined by VIRTUAL_PARTITION.
1182 Whenever a V_MAY_DEF is seen, all expressions dependent this
1183 VIRTUAL_PARTITION are removed from consideration.
1185 At the end of a basic block, all expression are removed from consideration
1186 in preparation for the next block.
1188 The end result is a vector over SSA_NAME_VERSION which is passed back to
1189 rewrite_out_of_ssa. As the SSA variables are being rewritten, instead of
1190 replacing the SSA_NAME tree element with the partition it was assigned,
1191 it is replaced with the RHS of the defining expression. */
1194 /* Dependency list element. This can contain either a partition index or a
1195 version number, depending on which list it is in. */
1197 typedef struct value_expr_d
1200 struct value_expr_d *next;
1204 /* Temporary Expression Replacement (TER) table information. */
1206 typedef struct temp_expr_table_d
1209 void **version_info;
1210 value_expr_p *partition_dep_list;
1212 bool saw_replaceable;
1213 int virtual_partition;
1214 bitmap partition_in_use;
1215 value_expr_p free_list;
1216 value_expr_p pending_dependence;
1217 } *temp_expr_table_p;
1219 /* Used to indicate a dependency on V_MAY_DEFs. */
1220 #define VIRTUAL_PARTITION(table) (table->virtual_partition)
1222 static temp_expr_table_p new_temp_expr_table (var_map);
1223 static tree *free_temp_expr_table (temp_expr_table_p);
1224 static inline value_expr_p new_value_expr (temp_expr_table_p);
1225 static inline void free_value_expr (temp_expr_table_p, value_expr_p);
1226 static inline value_expr_p find_value_in_list (value_expr_p, int,
1228 static inline void add_value_to_list (temp_expr_table_p, value_expr_p *, int);
1229 static inline void add_info_to_list (temp_expr_table_p, value_expr_p *,
1231 static value_expr_p remove_value_from_list (value_expr_p *, int);
1232 static void add_dependance (temp_expr_table_p, int, tree);
1233 static bool check_replaceable (temp_expr_table_p, tree);
1234 static void finish_expr (temp_expr_table_p, int, bool);
1235 static void mark_replaceable (temp_expr_table_p, tree);
1236 static inline void kill_expr (temp_expr_table_p, int, bool);
1237 static inline void kill_virtual_exprs (temp_expr_table_p, bool);
1238 static void find_replaceable_in_bb (temp_expr_table_p, basic_block);
1239 static tree *find_replaceable_exprs (var_map);
1240 static void dump_replaceable_exprs (FILE *, tree *);
1243 /* Create a new TER table for MAP. */
1245 static temp_expr_table_p
1246 new_temp_expr_table (var_map map)
1248 temp_expr_table_p t;
1250 t = (temp_expr_table_p) xmalloc (sizeof (struct temp_expr_table_d));
1253 t->version_info = xcalloc (num_ssa_names + 1, sizeof (void *));
1254 t->partition_dep_list = xcalloc (num_var_partitions (map) + 1,
1255 sizeof (value_expr_p));
1257 t->replaceable = BITMAP_XMALLOC ();
1258 t->partition_in_use = BITMAP_XMALLOC ();
1260 t->saw_replaceable = false;
1261 t->virtual_partition = num_var_partitions (map);
1262 t->free_list = NULL;
1263 t->pending_dependence = NULL;
1269 /* Free TER table T. If there are valid replacements, return the expression
1273 free_temp_expr_table (temp_expr_table_p t)
1278 #ifdef ENABLE_CHECKING
1280 for (x = 0; x <= num_var_partitions (t->map); x++)
1281 gcc_assert (!t->partition_dep_list[x]);
1284 while ((p = t->free_list))
1286 t->free_list = p->next;
1290 BITMAP_XFREE (t->partition_in_use);
1291 BITMAP_XFREE (t->replaceable);
1293 free (t->partition_dep_list);
1294 if (t->saw_replaceable)
1295 ret = (tree *)t->version_info;
1297 free (t->version_info);
1304 /* Allocate a new value list node. Take it from the free list in TABLE if
1307 static inline value_expr_p
1308 new_value_expr (temp_expr_table_p table)
1311 if (table->free_list)
1313 p = table->free_list;
1314 table->free_list = p->next;
1317 p = (value_expr_p) xmalloc (sizeof (struct value_expr_d));
1323 /* Add value list node P to the free list in TABLE. */
1326 free_value_expr (temp_expr_table_p table, value_expr_p p)
1328 p->next = table->free_list;
1329 table->free_list = p;
1333 /* Find VALUE if it's in LIST. Return a pointer to the list object if found,
1334 else return NULL. If LAST_PTR is provided, it will point to the previous
1335 item upon return, or NULL if this is the first item in the list. */
1337 static inline value_expr_p
1338 find_value_in_list (value_expr_p list, int value, value_expr_p *last_ptr)
1341 value_expr_p last = NULL;
1343 for (curr = list; curr; last = curr, curr = curr->next)
1345 if (curr->value == value)
1354 /* Add VALUE to LIST, if it isn't already present. TAB is the expression
1358 add_value_to_list (temp_expr_table_p tab, value_expr_p *list, int value)
1362 if (!find_value_in_list (*list, value, NULL))
1364 info = new_value_expr (tab);
1365 info->value = value;
1372 /* Add value node INFO if it's value isn't already in LIST. Free INFO if
1373 it is already in the list. TAB is the expression table. */
1376 add_info_to_list (temp_expr_table_p tab, value_expr_p *list, value_expr_p info)
1378 if (find_value_in_list (*list, info->value, NULL))
1379 free_value_expr (tab, info);
1388 /* Look for VALUE in LIST. If found, remove it from the list and return it's
1392 remove_value_from_list (value_expr_p *list, int value)
1394 value_expr_p info, last;
1396 info = find_value_in_list (*list, value, &last);
1402 last->next = info->next;
1408 /* Add a dependency between the def of ssa VERSION and VAR. If VAR is
1409 replaceable by an expression, add a dependence each of the elements of the
1410 expression. These are contained in the pending list. TAB is the
1411 expression table. */
1414 add_dependance (temp_expr_table_p tab, int version, tree var)
1419 i = SSA_NAME_VERSION (var);
1420 if (bitmap_bit_p (tab->replaceable, i))
1422 /* This variable is being substituted, so use whatever dependences
1423 were queued up when we marked this as replaceable earlier. */
1424 while ((info = tab->pending_dependence))
1426 tab->pending_dependence = info->next;
1427 /* Get the partition this variable was dependent on. Reuse this
1428 object to represent the current expression instead. */
1430 info->value = version;
1431 add_info_to_list (tab, &(tab->partition_dep_list[x]), info);
1432 add_value_to_list (tab,
1433 (value_expr_p *)&(tab->version_info[version]), x);
1434 bitmap_set_bit (tab->partition_in_use, x);
1439 i = var_to_partition (tab->map, var);
1440 gcc_assert (i != NO_PARTITION);
1441 add_value_to_list (tab, &(tab->partition_dep_list[i]), version);
1442 add_value_to_list (tab,
1443 (value_expr_p *)&(tab->version_info[version]), i);
1444 bitmap_set_bit (tab->partition_in_use, i);
1449 /* Check if expression STMT is suitable for replacement in table TAB. If so,
1450 create an expression entry. Return true if this stmt is replaceable. */
1453 check_replaceable (temp_expr_table_p tab, tree stmt)
1456 vuse_optype vuseops;
1460 int num_use_ops, version;
1461 var_map map = tab->map;
1465 if (TREE_CODE (stmt) != MODIFY_EXPR)
1468 ann = stmt_ann (stmt);
1469 defs = DEF_OPS (ann);
1471 /* Punt if there is more than 1 def, or more than 1 use. */
1472 if (NUM_DEFS (defs) != 1)
1474 def = DEF_OP (defs, 0);
1475 if (version_ref_count (map, def) != 1)
1478 /* There must be no V_MAY_DEFS. */
1479 if (NUM_V_MAY_DEFS (V_MAY_DEF_OPS (ann)) != 0)
1482 /* There must be no V_MUST_DEFS. */
1483 if (NUM_V_MUST_DEFS (V_MUST_DEF_OPS (ann)) != 0)
1486 /* Float expressions must go through memory if float-store is on. */
1487 if (flag_float_store && FLOAT_TYPE_P (TREE_TYPE (TREE_OPERAND (stmt, 1))))
1490 /* Calls to functions with side-effects cannot be replaced. */
1491 if ((call_expr = get_call_expr_in (stmt)) != NULL_TREE)
1493 int call_flags = call_expr_flags (call_expr);
1494 if (TREE_SIDE_EFFECTS (call_expr)
1495 && !(call_flags & (ECF_PURE | ECF_CONST | ECF_NORETURN)))
1499 uses = USE_OPS (ann);
1500 num_use_ops = NUM_USES (uses);
1501 vuseops = VUSE_OPS (ann);
1503 /* Any expression which has no virtual operands and no real operands
1504 should have been propagated if it's possible to do anything with them.
1505 If this happens here, it probably exists that way for a reason, so we
1506 won't touch it. An example is:
1508 There are no virtual uses nor any real uses, so we just leave this
1509 alone to be safe. */
1511 if (num_use_ops == 0 && NUM_VUSES (vuseops) == 0)
1514 version = SSA_NAME_VERSION (def);
1516 /* Add this expression to the dependency list for each use partition. */
1517 FOR_EACH_SSA_TREE_OPERAND (var, stmt, iter, SSA_OP_USE)
1519 add_dependance (tab, version, var);
1522 /* If there are VUSES, add a dependence on virtual defs. */
1523 if (NUM_VUSES (vuseops) != 0)
1525 add_value_to_list (tab, (value_expr_p *)&(tab->version_info[version]),
1526 VIRTUAL_PARTITION (tab));
1527 add_value_to_list (tab,
1528 &(tab->partition_dep_list[VIRTUAL_PARTITION (tab)]),
1530 bitmap_set_bit (tab->partition_in_use, VIRTUAL_PARTITION (tab));
1537 /* This function will remove the expression for VERSION from replacement
1538 consideration.n table TAB If 'replace' is true, it is marked as
1539 replaceable, otherwise not. */
1542 finish_expr (temp_expr_table_p tab, int version, bool replace)
1544 value_expr_p info, tmp;
1547 /* Remove this expression from its dependent lists. The partition dependence
1548 list is retained and transfered later to whomever uses this version. */
1549 for (info = (value_expr_p) tab->version_info[version]; info; info = tmp)
1551 partition = info->value;
1552 gcc_assert (tab->partition_dep_list[partition]);
1553 tmp = remove_value_from_list (&(tab->partition_dep_list[partition]),
1556 free_value_expr (tab, tmp);
1557 /* Only clear the bit when the dependency list is emptied via
1558 a replacement. Otherwise kill_expr will take care of it. */
1559 if (!(tab->partition_dep_list[partition]) && replace)
1560 bitmap_clear_bit (tab->partition_in_use, partition);
1563 free_value_expr (tab, info);
1568 tab->saw_replaceable = true;
1569 bitmap_set_bit (tab->replaceable, version);
1573 gcc_assert (!bitmap_bit_p (tab->replaceable, version));
1574 tab->version_info[version] = NULL;
1579 /* Mark the expression associated with VAR as replaceable, and enter
1580 the defining stmt into the version_info table TAB. */
1583 mark_replaceable (temp_expr_table_p tab, tree var)
1586 int version = SSA_NAME_VERSION (var);
1587 finish_expr (tab, version, true);
1589 /* Move the dependence list to the pending list. */
1590 if (tab->version_info[version])
1592 info = (value_expr_p) tab->version_info[version];
1593 for ( ; info->next; info = info->next)
1595 info->next = tab->pending_dependence;
1596 tab->pending_dependence = (value_expr_p)tab->version_info[version];
1599 tab->version_info[version] = SSA_NAME_DEF_STMT (var);
1603 /* This function marks any expression in TAB which is dependent on PARTITION
1604 as NOT replaceable. CLEAR_BIT is used to determine whether partition_in_use
1605 should have its bit cleared. Since this routine can be called within an
1606 EXECUTE_IF_SET_IN_BITMAP, the bit can't always be cleared. */
1609 kill_expr (temp_expr_table_p tab, int partition, bool clear_bit)
1613 /* Mark every active expr dependent on this var as not replaceable. */
1614 while ((ptr = tab->partition_dep_list[partition]) != NULL)
1615 finish_expr (tab, ptr->value, false);
1618 bitmap_clear_bit (tab->partition_in_use, partition);
1622 /* This function kills all expressions in TAB which are dependent on virtual
1623 DEFs. CLEAR_BIT determines whether partition_in_use gets cleared. */
1626 kill_virtual_exprs (temp_expr_table_p tab, bool clear_bit)
1628 kill_expr (tab, VIRTUAL_PARTITION (tab), clear_bit);
1632 /* This function processes basic block BB, and looks for variables which can
1633 be replaced by their expressions. Results are stored in TAB. */
1636 find_replaceable_in_bb (temp_expr_table_p tab, basic_block bb)
1638 block_stmt_iterator bsi;
1642 var_map map = tab->map;
1646 for (bsi = bsi_start (bb); !bsi_end_p (bsi); bsi_next (&bsi))
1648 stmt = bsi_stmt (bsi);
1649 ann = stmt_ann (stmt);
1651 /* Determine if this stmt finishes an existing expression. */
1652 FOR_EACH_SSA_TREE_OPERAND (def, stmt, iter, SSA_OP_USE)
1654 if (tab->version_info[SSA_NAME_VERSION (def)])
1656 /* Mark expression as replaceable unless stmt is volatile. */
1657 if (!ann->has_volatile_ops)
1658 mark_replaceable (tab, def);
1660 finish_expr (tab, SSA_NAME_VERSION (def), false);
1664 /* Next, see if this stmt kills off an active expression. */
1665 FOR_EACH_SSA_TREE_OPERAND (def, stmt, iter, SSA_OP_DEF)
1667 partition = var_to_partition (map, def);
1668 if (partition != NO_PARTITION && tab->partition_dep_list[partition])
1669 kill_expr (tab, partition, true);
1672 /* Now see if we are creating a new expression or not. */
1673 if (!ann->has_volatile_ops)
1674 check_replaceable (tab, stmt);
1676 /* Free any unused dependency lists. */
1677 while ((p = tab->pending_dependence))
1679 tab->pending_dependence = p->next;
1680 free_value_expr (tab, p);
1683 /* A V_MAY_DEF kills any expression using a virtual operand. */
1684 if (NUM_V_MAY_DEFS (V_MAY_DEF_OPS (ann)) > 0)
1685 kill_virtual_exprs (tab, true);
1687 /* A V_MUST_DEF kills any expression using a virtual operand. */
1688 if (NUM_V_MUST_DEFS (V_MUST_DEF_OPS (ann)) > 0)
1689 kill_virtual_exprs (tab, true);
1694 /* This function is the driver routine for replacement of temporary expressions
1695 in the SSA->normal phase, operating on MAP. If there are replaceable
1696 expressions, a table is returned which maps SSA versions to the
1697 expressions they should be replaced with. A NULL_TREE indicates no
1698 replacement should take place. If there are no replacements at all,
1699 NULL is returned by the function, otherwise an expression vector indexed
1700 by SSA_NAME version numbers. */
1703 find_replaceable_exprs (var_map map)
1707 temp_expr_table_p table;
1710 table = new_temp_expr_table (map);
1715 find_replaceable_in_bb (table, bb);
1716 EXECUTE_IF_SET_IN_BITMAP ((table->partition_in_use), 0, i, bi)
1718 kill_expr (table, i, false);
1722 ret = free_temp_expr_table (table);
1727 /* Dump TER expression table EXPR to file F. */
1730 dump_replaceable_exprs (FILE *f, tree *expr)
1734 fprintf (f, "\nReplacing Expressions\n");
1735 for (x = 0; x < (int)num_ssa_names + 1; x++)
1739 var = DEF_OP (STMT_DEF_OPS (stmt), 0);
1740 print_generic_expr (f, var, TDF_SLIM);
1741 fprintf (f, " replace with --> ");
1742 print_generic_expr (f, TREE_OPERAND (stmt, 1), TDF_SLIM);
1749 /* Helper function for discover_nonconstant_array_refs.
1750 Look for ARRAY_REF nodes with non-constant indexes and mark them
1754 discover_nonconstant_array_refs_r (tree * tp, int *walk_subtrees,
1755 void *data ATTRIBUTE_UNUSED)
1759 if (IS_TYPE_OR_DECL_P (t))
1761 else if (TREE_CODE (t) == ARRAY_REF || TREE_CODE (t) == ARRAY_RANGE_REF)
1763 while (((TREE_CODE (t) == ARRAY_REF || TREE_CODE (t) == ARRAY_RANGE_REF)
1764 && is_gimple_min_invariant (TREE_OPERAND (t, 1))
1765 && (!TREE_OPERAND (t, 2)
1766 || is_gimple_min_invariant (TREE_OPERAND (t, 2))))
1767 || (TREE_CODE (t) == COMPONENT_REF
1768 && (!TREE_OPERAND (t,2)
1769 || is_gimple_min_invariant (TREE_OPERAND (t, 2))))
1770 || TREE_CODE (t) == BIT_FIELD_REF
1771 || TREE_CODE (t) == REALPART_EXPR
1772 || TREE_CODE (t) == IMAGPART_EXPR
1773 || TREE_CODE (t) == VIEW_CONVERT_EXPR
1774 || TREE_CODE (t) == NOP_EXPR
1775 || TREE_CODE (t) == CONVERT_EXPR)
1776 t = TREE_OPERAND (t, 0);
1778 if (TREE_CODE (t) == ARRAY_REF || TREE_CODE (t) == ARRAY_RANGE_REF)
1780 t = get_base_address (t);
1781 if (t && DECL_P (t))
1782 TREE_ADDRESSABLE (t) = 1;
1792 /* RTL expansion is not able to compile array references with variable
1793 offsets for arrays stored in single register. Discover such
1794 expressions and mark variables as addressable to avoid this
1798 discover_nonconstant_array_refs (void)
1801 block_stmt_iterator bsi;
1805 for (bsi = bsi_start (bb); !bsi_end_p (bsi); bsi_next (&bsi))
1806 walk_tree (bsi_stmt_ptr (bsi), discover_nonconstant_array_refs_r,
1812 /* This function will rewrite the current program using the variable mapping
1813 found in MAP. If the replacement vector VALUES is provided, any
1814 occurrences of partitions with non-null entries in the vector will be
1815 replaced with the expression in the vector instead of its mapped
1819 rewrite_trees (var_map map, tree *values)
1823 block_stmt_iterator si;
1828 #ifdef ENABLE_CHECKING
1829 /* Search for PHIs where the destination has no partition, but one
1830 or more arguments has a partition. This should not happen and can
1831 create incorrect code. */
1836 for (phi = phi_nodes (bb); phi; phi = PHI_CHAIN (phi))
1838 tree T0 = var_to_partition_to_var (map, PHI_RESULT (phi));
1840 if (T0 == NULL_TREE)
1844 for (i = 0; i < PHI_NUM_ARGS (phi); i++)
1846 tree arg = PHI_ARG_DEF (phi, i);
1848 if (TREE_CODE (arg) == SSA_NAME
1849 && var_to_partition (map, arg) != NO_PARTITION)
1851 fprintf (stderr, "Argument of PHI is in a partition :(");
1852 print_generic_expr (stderr, arg, TDF_SLIM);
1853 fprintf (stderr, "), but the result is not :");
1854 print_generic_stmt (stderr, phi, TDF_SLIM);
1855 internal_error ("SSA corruption");
1863 /* Replace PHI nodes with any required copies. */
1864 g = new_elim_graph (map->num_partitions);
1868 for (si = bsi_start (bb); !bsi_end_p (si); )
1870 size_t num_uses, num_defs;
1873 tree stmt = bsi_stmt (si);
1874 use_operand_p use_p;
1875 def_operand_p def_p;
1876 int remove = 0, is_copy = 0;
1880 get_stmt_operands (stmt);
1881 ann = stmt_ann (stmt);
1884 if (TREE_CODE (stmt) == MODIFY_EXPR
1885 && (TREE_CODE (TREE_OPERAND (stmt, 1)) == SSA_NAME))
1888 uses = USE_OPS (ann);
1889 num_uses = NUM_USES (uses);
1890 FOR_EACH_SSA_USE_OPERAND (use_p, stmt, iter, SSA_OP_USE)
1892 if (replace_use_variable (map, use_p, values))
1896 defs = DEF_OPS (ann);
1897 num_defs = NUM_DEFS (defs);
1899 /* Mark this stmt for removal if it is the list of replaceable
1901 if (values && num_defs == 1)
1903 tree def = DEF_OP (defs, 0);
1905 val = values[SSA_NAME_VERSION (def)];
1911 FOR_EACH_SSA_DEF_OPERAND (def_p, stmt, iter, SSA_OP_DEF)
1913 if (replace_def_variable (map, def_p, NULL))
1916 /* If both SSA_NAMEs coalesce to the same variable,
1917 mark the now redundant copy for removal. */
1920 && (DEF_FROM_PTR (def_p) == USE_OP (uses, 0)))
1923 if (changed & !remove)
1927 /* Remove any stmts marked for removal. */
1934 phi = phi_nodes (bb);
1938 FOR_EACH_EDGE (e, ei, bb->preds)
1939 eliminate_phi (e, g);
1943 delete_elim_graph (g);
1947 /* These are the local work structures used to determine the best place to
1948 insert the copies that were placed on edges by the SSA->normal pass.. */
1949 static varray_type edge_leader = NULL;
1950 static varray_type GTY(()) stmt_list = NULL;
1951 static bitmap leader_has_match = NULL;
1952 static edge leader_match = NULL;
1955 /* Pass this function to make_forwarder_block so that all the edges with
1956 matching PENDING_STMT lists to 'curr_stmt_list' get redirected. */
1958 same_stmt_list_p (edge e)
1960 return (e->aux == (PTR) leader_match) ? true : false;
1964 /* Return TRUE if S1 and S2 are equivalent copies. */
1966 identical_copies_p (tree s1, tree s2)
1968 #ifdef ENABLE_CHECKING
1969 gcc_assert (TREE_CODE (s1) == MODIFY_EXPR);
1970 gcc_assert (TREE_CODE (s2) == MODIFY_EXPR);
1971 gcc_assert (DECL_P (TREE_OPERAND (s1, 0)));
1972 gcc_assert (DECL_P (TREE_OPERAND (s2, 0)));
1975 if (TREE_OPERAND (s1, 0) != TREE_OPERAND (s2, 0))
1978 s1 = TREE_OPERAND (s1, 1);
1979 s2 = TREE_OPERAND (s2, 1);
1988 /* Compare the PENDING_STMT list for two edges, and return true if the lists
1989 contain the same sequence of copies. */
1992 identical_stmt_lists_p (edge e1, edge e2)
1994 tree t1 = PENDING_STMT (e1);
1995 tree t2 = PENDING_STMT (e2);
1996 tree_stmt_iterator tsi1, tsi2;
1998 gcc_assert (TREE_CODE (t1) == STATEMENT_LIST);
1999 gcc_assert (TREE_CODE (t2) == STATEMENT_LIST);
2001 for (tsi1 = tsi_start (t1), tsi2 = tsi_start (t2);
2002 !tsi_end_p (tsi1) && !tsi_end_p (tsi2);
2003 tsi_next (&tsi1), tsi_next (&tsi2))
2005 if (!identical_copies_p (tsi_stmt (tsi1), tsi_stmt (tsi2)))
2009 if (!tsi_end_p (tsi1) || ! tsi_end_p (tsi2))
2016 /* Look at all the incoming edges to block BB, and decide where the best place
2017 to insert the stmts on each edge are, and perform those insertions. Output
2018 any debug information to DEBUG_FILE. Return true if anything other than a
2019 standard edge insertion is done. */
2022 analyze_edges_for_bb (basic_block bb, FILE *debug_file)
2028 bool have_opportunity;
2029 block_stmt_iterator bsi;
2031 edge single_edge = NULL;
2036 /* Blocks which contain at least one abnormal edge cannot use
2037 make_forwarder_block. Look for these blocks, and commit any PENDING_STMTs
2038 found on edges in these block. */
2039 have_opportunity = true;
2040 FOR_EACH_EDGE (e, ei, bb->preds)
2041 if (e->flags & EDGE_ABNORMAL)
2043 have_opportunity = false;
2047 if (!have_opportunity)
2049 FOR_EACH_EDGE (e, ei, bb->preds)
2050 if (PENDING_STMT (e))
2051 bsi_commit_one_edge_insert (e, NULL);
2054 /* Find out how many edges there are with interesting pending stmts on them.
2055 Commit the stmts on edges we are not interested in. */
2056 FOR_EACH_EDGE (e, ei, bb->preds)
2058 if (PENDING_STMT (e))
2060 gcc_assert (!(e->flags & EDGE_ABNORMAL));
2061 if (e->flags & EDGE_FALLTHRU)
2063 bsi = bsi_start (e->src);
2064 if (!bsi_end_p (bsi))
2066 stmt = bsi_stmt (bsi);
2068 gcc_assert (stmt != NULL_TREE);
2069 is_label = (TREE_CODE (stmt) == LABEL_EXPR);
2070 /* Punt if it has non-label stmts, or isn't local. */
2071 if (!is_label || DECL_NONLOCAL (TREE_OPERAND (stmt, 0))
2072 || !bsi_end_p (bsi))
2074 bsi_commit_one_edge_insert (e, NULL);
2084 /* If there aren't at least 2 edges, no sharing will happen. */
2088 bsi_commit_one_edge_insert (single_edge, NULL);
2092 /* Ensure that we have empty worklists. */
2093 if (edge_leader == NULL)
2095 VARRAY_EDGE_INIT (edge_leader, 25, "edge_leader");
2096 VARRAY_TREE_INIT (stmt_list, 25, "stmt_list");
2097 leader_has_match = BITMAP_XMALLOC ();
2101 #ifdef ENABLE_CHECKING
2102 gcc_assert (VARRAY_ACTIVE_SIZE (edge_leader) == 0);
2103 gcc_assert (VARRAY_ACTIVE_SIZE (stmt_list) == 0);
2104 gcc_assert (bitmap_empty_p (leader_has_match));
2108 /* Find the "leader" block for each set of unique stmt lists. Preference is
2109 given to FALLTHRU blocks since they would need a GOTO to arrive at another
2110 block. The leader edge destination is the block which all the other edges
2111 with the same stmt list will be redirected to. */
2112 have_opportunity = false;
2113 FOR_EACH_EDGE (e, ei, bb->preds)
2115 if (PENDING_STMT (e))
2119 /* Look for the same stmt list in edge leaders list. */
2120 for (x = 0; x < VARRAY_ACTIVE_SIZE (edge_leader); x++)
2122 edge leader = VARRAY_EDGE (edge_leader, x);
2123 if (identical_stmt_lists_p (leader, e))
2125 /* Give this edge the same stmt list pointer. */
2126 PENDING_STMT (e) = NULL;
2128 bitmap_set_bit (leader_has_match, x);
2129 have_opportunity = found = true;
2134 /* If no similar stmt list, add this edge to the leader list. */
2137 VARRAY_PUSH_EDGE (edge_leader, e);
2138 VARRAY_PUSH_TREE (stmt_list, PENDING_STMT (e));
2143 /* If there are no similar lists, just issue the stmts. */
2144 if (!have_opportunity)
2146 for (x = 0; x < VARRAY_ACTIVE_SIZE (edge_leader); x++)
2147 bsi_commit_one_edge_insert (VARRAY_EDGE (edge_leader, x), NULL);
2148 VARRAY_POP_ALL (edge_leader);
2149 VARRAY_POP_ALL (stmt_list);
2150 bitmap_clear (leader_has_match);
2156 fprintf (debug_file, "\nOpportunities in BB %d for stmt/block reduction:\n",
2160 /* For each common list, create a forwarding block and issue the stmt's
2162 for (x = 0 ; x < VARRAY_ACTIVE_SIZE (edge_leader); x++)
2163 if (bitmap_bit_p (leader_has_match, x))
2165 edge new_edge, leader_edge;
2166 block_stmt_iterator bsi;
2167 tree curr_stmt_list;
2169 leader_match = leader_edge = VARRAY_EDGE (edge_leader, x);
2171 /* The tree_* cfg manipulation routines use the PENDING_EDGE field
2172 for various PHI manipulations, so it gets cleared whhen calls are
2173 made to make_forwarder_block(). So make sure the edge is clear,
2174 and use the saved stmt list. */
2175 PENDING_STMT (leader_edge) = NULL;
2176 leader_edge->aux = leader_edge;
2177 curr_stmt_list = VARRAY_TREE (stmt_list, x);
2179 new_edge = make_forwarder_block (leader_edge->dest, same_stmt_list_p,
2181 bb = new_edge->dest;
2184 fprintf (debug_file, "Splitting BB %d for Common stmt list. ",
2185 leader_edge->dest->index);
2186 fprintf (debug_file, "Original block is now BB%d.\n", bb->index);
2187 print_generic_stmt (debug_file, curr_stmt_list, TDF_VOPS);
2190 FOR_EACH_EDGE (e, ei, new_edge->src->preds)
2194 fprintf (debug_file, " Edge (%d->%d) lands here.\n",
2195 e->src->index, e->dest->index);
2198 bsi = bsi_last (leader_edge->dest);
2199 bsi_insert_after (&bsi, curr_stmt_list, BSI_NEW_STMT);
2201 leader_match = NULL;
2202 /* We should never get a new block now. */
2206 e = VARRAY_EDGE (edge_leader, x);
2207 PENDING_STMT (e) = VARRAY_TREE (stmt_list, x);
2208 bsi_commit_one_edge_insert (e, NULL);
2212 /* Clear the working data structures. */
2213 VARRAY_POP_ALL (edge_leader);
2214 VARRAY_POP_ALL (stmt_list);
2215 bitmap_clear (leader_has_match);
2221 /* This function will analyze the insertions which were performed on edges,
2222 and decide whether they should be left on that edge, or whether it is more
2223 efficient to emit some subset of them in a single block. All stmts are
2224 inserted somewhere, and if non-NULL, debug information is printed via
2228 perform_edge_inserts (FILE *dump_file)
2231 bool changed = false;
2234 fprintf(dump_file, "Analyzing Edge Insertions.\n");
2237 changed |= analyze_edges_for_bb (bb, dump_file);
2239 changed |= analyze_edges_for_bb (EXIT_BLOCK_PTR, dump_file);
2241 /* Clear out any tables which were created. */
2243 BITMAP_XFREE (leader_has_match);
2247 free_dominance_info (CDI_DOMINATORS);
2248 free_dominance_info (CDI_POST_DOMINATORS);
2251 #ifdef ENABLE_CHECKING
2257 FOR_EACH_EDGE (e, ei, bb->preds)
2259 if (PENDING_STMT (e))
2260 error (" Pending stmts not issued on PRED edge (%d, %d)\n",
2261 e->src->index, e->dest->index);
2263 FOR_EACH_EDGE (e, ei, bb->succs)
2265 if (PENDING_STMT (e))
2266 error (" Pending stmts not issued on SUCC edge (%d, %d)\n",
2267 e->src->index, e->dest->index);
2270 FOR_EACH_EDGE (e, ei, ENTRY_BLOCK_PTR->succs)
2272 if (PENDING_STMT (e))
2273 error (" Pending stmts not issued on ENTRY edge (%d, %d)\n",
2274 e->src->index, e->dest->index);
2276 FOR_EACH_EDGE (e, ei, EXIT_BLOCK_PTR->preds)
2278 if (PENDING_STMT (e))
2279 error (" Pending stmts not issued on EXIT edge (%d, %d)\n",
2280 e->src->index, e->dest->index);
2287 /* Remove the variables specified in MAP from SSA form. Any debug information
2288 is sent to DUMP. FLAGS indicate what options should be used. */
2291 remove_ssa_form (FILE *dump, var_map map, int flags)
2293 tree_live_info_p liveinfo;
2297 tree *values = NULL;
2302 /* If we are not combining temps, don't calculate live ranges for variables
2303 with only one SSA version. */
2304 if ((flags & SSANORM_COMBINE_TEMPS) == 0)
2305 compact_var_map (map, VARMAP_NO_SINGLE_DEFS);
2307 compact_var_map (map, VARMAP_NORMAL);
2309 if (dump_file && (dump_flags & TDF_DETAILS))
2310 dump_var_map (dump_file, map);
2312 liveinfo = coalesce_ssa_name (map, flags);
2314 /* Make sure even single occurrence variables are in the list now. */
2315 if ((flags & SSANORM_COMBINE_TEMPS) == 0)
2316 compact_var_map (map, VARMAP_NORMAL);
2318 if (dump_file && (dump_flags & TDF_DETAILS))
2320 fprintf (dump_file, "After Coalescing:\n");
2321 dump_var_map (dump_file, map);
2324 if (flags & SSANORM_PERFORM_TER)
2326 values = find_replaceable_exprs (map);
2327 if (values && dump_file && (dump_flags & TDF_DETAILS))
2328 dump_replaceable_exprs (dump_file, values);
2331 /* Assign real variables to the partitions now. */
2334 if (dump_file && (dump_flags & TDF_DETAILS))
2336 fprintf (dump_file, "After Root variable replacement:\n");
2337 dump_var_map (dump_file, map);
2340 if ((flags & SSANORM_COMBINE_TEMPS) && liveinfo)
2342 coalesce_vars (map, liveinfo);
2343 if (dump_file && (dump_flags & TDF_DETAILS))
2345 fprintf (dump_file, "After variable memory coalescing:\n");
2346 dump_var_map (dump_file, map);
2351 delete_tree_live_info (liveinfo);
2353 rewrite_trees (map, values);
2358 /* Remove phi nodes which have been translated back to real variables. */
2361 for (phi = phi_nodes (bb); phi; phi = next)
2363 next = PHI_CHAIN (phi);
2364 if ((flags & SSANORM_REMOVE_ALL_PHIS)
2365 || var_to_partition (map, PHI_RESULT (phi)) != NO_PARTITION)
2366 remove_phi_node (phi, NULL_TREE, bb);
2370 /* If any copies were inserted on edges, analyze and insert them now. */
2371 perform_edge_inserts (dump_file);
2376 /* Search every PHI node for arguments associated with backedges which
2377 we can trivially determine will need a copy (the argument is either
2378 not an SSA_NAME or the argument has a different underlying variable
2379 than the PHI result).
2381 Insert a copy from the PHI argument to a new destination at the
2382 end of the block with the backedge to the top of the loop. Update
2383 the PHI argument to reference this new destination. */
2386 insert_backedge_copies (void)
2394 for (phi = phi_nodes (bb); phi; phi = PHI_CHAIN (phi))
2396 tree result = PHI_RESULT (phi);
2400 if (!is_gimple_reg (result))
2403 result_var = SSA_NAME_VAR (result);
2404 for (i = 0; i < PHI_NUM_ARGS (phi); i++)
2406 tree arg = PHI_ARG_DEF (phi, i);
2407 edge e = PHI_ARG_EDGE (phi, i);
2409 /* If the argument is not an SSA_NAME, then we will
2410 need a constant initialization. If the argument is
2411 an SSA_NAME with a different underlying variable and
2412 we are not combining temporaries, then we will
2413 need a copy statement. */
2414 if ((e->flags & EDGE_DFS_BACK)
2415 && (TREE_CODE (arg) != SSA_NAME
2416 || (!flag_tree_combine_temps
2417 && SSA_NAME_VAR (arg) != result_var)))
2419 tree stmt, name, last = NULL;
2420 block_stmt_iterator bsi;
2422 bsi = bsi_last (PHI_ARG_EDGE (phi, i)->src);
2423 if (!bsi_end_p (bsi))
2424 last = bsi_stmt (bsi);
2426 /* In theory the only way we ought to get back to the
2427 start of a loop should be with a COND_EXPR or GOTO_EXPR.
2428 However, better safe than sorry.
2430 If the block ends with a control statement or
2431 something that might throw, then we have to
2432 insert this assignment before the last
2433 statement. Else insert it after the last statement. */
2434 if (last && stmt_ends_bb_p (last))
2436 /* If the last statement in the block is the definition
2437 site of the PHI argument, then we can't insert
2438 anything after it. */
2439 if (TREE_CODE (arg) == SSA_NAME
2440 && SSA_NAME_DEF_STMT (arg) == last)
2444 /* Create a new instance of the underlying
2445 variable of the PHI result. */
2446 stmt = build (MODIFY_EXPR, TREE_TYPE (result_var),
2447 NULL, PHI_ARG_DEF (phi, i));
2448 name = make_ssa_name (result_var, stmt);
2449 TREE_OPERAND (stmt, 0) = name;
2451 /* Insert the new statement into the block and update
2453 if (last && stmt_ends_bb_p (last))
2454 bsi_insert_before (&bsi, stmt, BSI_NEW_STMT);
2456 bsi_insert_after (&bsi, stmt, BSI_NEW_STMT);
2458 SET_PHI_ARG_DEF (phi, i, name);
2465 /* Take the current function out of SSA form, as described in
2466 R. Morgan, ``Building an Optimizing Compiler'',
2467 Butterworth-Heinemann, Boston, MA, 1998. pp 176-186. */
2470 rewrite_out_of_ssa (void)
2474 int ssa_flags = (SSANORM_REMOVE_ALL_PHIS | SSANORM_USE_COALESCE_LIST);
2476 /* If elimination of a PHI requires inserting a copy on a backedge,
2477 then we will have to split the backedge which has numerous
2478 undesirable performance effects.
2480 A significant number of such cases can be handled here by inserting
2481 copies into the loop itself. */
2482 insert_backedge_copies ();
2484 if (!flag_tree_live_range_split)
2485 ssa_flags |= SSANORM_COALESCE_PARTITIONS;
2487 eliminate_virtual_phis ();
2489 if (dump_file && (dump_flags & TDF_DETAILS))
2490 dump_tree_cfg (dump_file, dump_flags & ~TDF_DETAILS);
2492 /* We cannot allow unssa to un-gimplify trees before we instrument them. */
2493 if (flag_tree_ter && !flag_mudflap)
2494 var_flags = SSA_VAR_MAP_REF_COUNT;
2496 map = create_ssa_var_map (var_flags);
2498 if (flag_tree_combine_temps)
2499 ssa_flags |= SSANORM_COMBINE_TEMPS;
2500 if (flag_tree_ter && !flag_mudflap)
2501 ssa_flags |= SSANORM_PERFORM_TER;
2503 remove_ssa_form (dump_file, map, ssa_flags);
2505 if (dump_file && (dump_flags & TDF_DETAILS))
2506 dump_tree_cfg (dump_file, dump_flags & ~TDF_DETAILS);
2508 /* Do some cleanups which reduce the amount of data the
2509 tree->rtl expanders deal with. */
2510 cfg_remove_useless_stmts ();
2512 /* Flush out flow graph and SSA data. */
2513 delete_var_map (map);
2515 /* Mark arrays indexed with non-constant indices with TREE_ADDRESSABLE. */
2516 discover_nonconstant_array_refs ();
2520 /* Define the parameters of the out of SSA pass. */
2522 struct tree_opt_pass pass_del_ssa =
2524 "optimized", /* name */
2526 rewrite_out_of_ssa, /* execute */
2529 0, /* static_pass_number */
2530 TV_TREE_SSA_TO_NORMAL, /* tv_id */
2531 PROP_cfg | PROP_ssa | PROP_alias, /* properties_required */
2532 0, /* properties_provided */
2533 /* ??? If TER is enabled, we also kill gimple. */
2534 PROP_ssa, /* properties_destroyed */
2535 TODO_verify_ssa | TODO_verify_flow
2536 | TODO_verify_stmts, /* todo_flags_start */
2537 TODO_dump_func | TODO_ggc_collect, /* todo_flags_finish */