1 /* Convert a program in SSA form into Normal form.
2 Copyright (C) 2004 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);
159 DECL_ARTIFICIAL (tmp) = DECL_ARTIFICIAL (t);
160 add_referenced_tmp_var (tmp);
162 /* add_referenced_tmp_var will create the annotation and set up some
163 of the flags in the annotation. However, some flags we need to
164 inherit from our original variable. */
165 var_ann (tmp)->type_mem_tag = var_ann (t)->type_mem_tag;
166 if (is_call_clobbered (t))
167 mark_call_clobbered (tmp);
173 /* This helper function fill insert a copy from a constant or variable SRC to
174 variable DEST on edge E. */
177 insert_copy_on_edge (edge e, tree dest, tree src)
181 copy = build (MODIFY_EXPR, TREE_TYPE (dest), dest, src);
184 if (TREE_CODE (src) == ADDR_EXPR)
185 src = TREE_OPERAND (src, 0);
186 if (TREE_CODE (src) == VAR_DECL || TREE_CODE (src) == PARM_DECL)
189 if (dump_file && (dump_flags & TDF_DETAILS))
192 "Inserting a copy on edge BB%d->BB%d :",
195 print_generic_expr (dump_file, copy, dump_flags);
196 fprintf (dump_file, "\n");
199 bsi_insert_on_edge (e, copy);
203 /* Create an elimination graph with SIZE nodes and associated data
207 new_elim_graph (int size)
209 elim_graph g = (elim_graph) xmalloc (sizeof (struct _elim_graph));
211 VARRAY_TREE_INIT (g->nodes, 30, "Elimination Node List");
212 VARRAY_TREE_INIT (g->const_copies, 20, "Elimination Constant Copies");
213 VARRAY_INT_INIT (g->edge_list, 20, "Elimination Edge List");
214 VARRAY_INT_INIT (g->stack, 30, " Elimination Stack");
216 g->visited = sbitmap_alloc (size);
222 /* Empty elimination graph G. */
225 clear_elim_graph (elim_graph g)
227 VARRAY_POP_ALL (g->nodes);
228 VARRAY_POP_ALL (g->edge_list);
232 /* Delete elimination graph G. */
235 delete_elim_graph (elim_graph g)
237 sbitmap_free (g->visited);
242 /* Return the number of nodes in graph G. */
245 elim_graph_size (elim_graph g)
247 return VARRAY_ACTIVE_SIZE (g->nodes);
251 /* Add NODE to graph G, if it doesn't exist already. */
254 elim_graph_add_node (elim_graph g, tree node)
257 for (x = 0; x < elim_graph_size (g); x++)
258 if (VARRAY_TREE (g->nodes, x) == node)
260 VARRAY_PUSH_TREE (g->nodes, node);
264 /* Add the edge PRED->SUCC to graph G. */
267 elim_graph_add_edge (elim_graph g, int pred, int succ)
269 VARRAY_PUSH_INT (g->edge_list, pred);
270 VARRAY_PUSH_INT (g->edge_list, succ);
274 /* Remove an edge from graph G for which NODE is the predecessor, and
275 return the successor node. -1 is returned if there is no such edge. */
278 elim_graph_remove_succ_edge (elim_graph g, int node)
282 for (x = 0; x < VARRAY_ACTIVE_SIZE (g->edge_list); x += 2)
283 if (VARRAY_INT (g->edge_list, x) == node)
285 VARRAY_INT (g->edge_list, x) = -1;
286 y = VARRAY_INT (g->edge_list, x + 1);
287 VARRAY_INT (g->edge_list, x + 1) = -1;
294 /* Find all the nodes in GRAPH which are successors to NODE in the
295 edge list. VAR will hold the partition number found. CODE is the
296 code fragment executed for every node found. */
298 #define FOR_EACH_ELIM_GRAPH_SUCC(GRAPH, NODE, VAR, CODE) \
302 for (x_ = 0; x_ < VARRAY_ACTIVE_SIZE ((GRAPH)->edge_list); x_ += 2) \
304 y_ = VARRAY_INT ((GRAPH)->edge_list, x_); \
307 (VAR) = VARRAY_INT ((GRAPH)->edge_list, x_ + 1); \
313 /* Find all the nodes which are predecessors of NODE in the edge list for
314 GRAPH. VAR will hold the partition number found. CODE is the
315 code fragment executed for every node found. */
317 #define FOR_EACH_ELIM_GRAPH_PRED(GRAPH, NODE, VAR, CODE) \
321 for (x_ = 0; x_ < VARRAY_ACTIVE_SIZE ((GRAPH)->edge_list); x_ += 2) \
323 y_ = VARRAY_INT ((GRAPH)->edge_list, x_ + 1); \
326 (VAR) = VARRAY_INT ((GRAPH)->edge_list, x_); \
332 /* Add T to elimination graph G. */
335 eliminate_name (elim_graph g, tree T)
337 elim_graph_add_node (g, T);
341 /* Build elimination graph G for basic block BB on incoming PHI edge
345 eliminate_build (elim_graph g, basic_block B)
351 clear_elim_graph (g);
353 for (phi = phi_nodes (B); phi; phi = PHI_CHAIN (phi))
355 T0 = var_to_partition_to_var (g->map, PHI_RESULT (phi));
357 /* Ignore results which are not in partitions. */
361 Ti = PHI_ARG_DEF (phi, g->e->dest_idx);
363 /* If this argument is a constant, or a SSA_NAME which is being
364 left in SSA form, just queue a copy to be emitted on this
366 if (!phi_ssa_name_p (Ti)
367 || (TREE_CODE (Ti) == SSA_NAME
368 && var_to_partition (g->map, Ti) == NO_PARTITION))
370 /* Save constant copies until all other copies have been emitted
372 VARRAY_PUSH_TREE (g->const_copies, T0);
373 VARRAY_PUSH_TREE (g->const_copies, Ti);
377 Ti = var_to_partition_to_var (g->map, Ti);
380 eliminate_name (g, T0);
381 eliminate_name (g, Ti);
382 p0 = var_to_partition (g->map, T0);
383 pi = var_to_partition (g->map, Ti);
384 elim_graph_add_edge (g, p0, pi);
391 /* Push successors of T onto the elimination stack for G. */
394 elim_forward (elim_graph g, int T)
397 SET_BIT (g->visited, T);
398 FOR_EACH_ELIM_GRAPH_SUCC (g, T, S,
400 if (!TEST_BIT (g->visited, S))
403 VARRAY_PUSH_INT (g->stack, T);
407 /* Return 1 if there unvisited predecessors of T in graph G. */
410 elim_unvisited_predecessor (elim_graph g, int T)
413 FOR_EACH_ELIM_GRAPH_PRED (g, T, P,
415 if (!TEST_BIT (g->visited, P))
421 /* Process predecessors first, and insert a copy. */
424 elim_backward (elim_graph g, int T)
427 SET_BIT (g->visited, T);
428 FOR_EACH_ELIM_GRAPH_PRED (g, T, P,
430 if (!TEST_BIT (g->visited, P))
432 elim_backward (g, P);
433 insert_copy_on_edge (g->e,
434 partition_to_var (g->map, P),
435 partition_to_var (g->map, T));
440 /* Insert required copies for T in graph G. Check for a strongly connected
441 region, and create a temporary to break the cycle if one is found. */
444 elim_create (elim_graph g, int T)
449 if (elim_unvisited_predecessor (g, T))
451 U = create_temp (partition_to_var (g->map, T));
452 insert_copy_on_edge (g->e, U, partition_to_var (g->map, T));
453 FOR_EACH_ELIM_GRAPH_PRED (g, T, P,
455 if (!TEST_BIT (g->visited, P))
457 elim_backward (g, P);
458 insert_copy_on_edge (g->e, partition_to_var (g->map, P), U);
464 S = elim_graph_remove_succ_edge (g, T);
467 SET_BIT (g->visited, T);
468 insert_copy_on_edge (g->e,
469 partition_to_var (g->map, T),
470 partition_to_var (g->map, S));
476 /* Eliminate all the phi nodes on edge E in graph G. */
479 eliminate_phi (edge e, elim_graph g)
483 basic_block B = e->dest;
485 gcc_assert (VARRAY_ACTIVE_SIZE (g->const_copies) == 0);
487 /* Abnormal edges already have everything coalesced, or the coalescer
488 would have aborted. */
489 if (e->flags & EDGE_ABNORMAL)
492 num_nodes = num_var_partitions (g->map);
495 eliminate_build (g, B);
497 if (elim_graph_size (g) != 0)
499 sbitmap_zero (g->visited);
500 VARRAY_POP_ALL (g->stack);
502 for (x = 0; x < elim_graph_size (g); x++)
504 tree var = VARRAY_TREE (g->nodes, x);
505 int p = var_to_partition (g->map, var);
506 if (!TEST_BIT (g->visited, p))
510 sbitmap_zero (g->visited);
511 while (VARRAY_ACTIVE_SIZE (g->stack) > 0)
513 x = VARRAY_TOP_INT (g->stack);
514 VARRAY_POP (g->stack);
515 if (!TEST_BIT (g->visited, x))
520 /* If there are any pending constant copies, issue them now. */
521 while (VARRAY_ACTIVE_SIZE (g->const_copies) > 0)
524 src = VARRAY_TOP_TREE (g->const_copies);
525 VARRAY_POP (g->const_copies);
526 dest = VARRAY_TOP_TREE (g->const_copies);
527 VARRAY_POP (g->const_copies);
528 insert_copy_on_edge (e, dest, src);
533 /* Shortcut routine to print messages to file F of the form:
534 "STR1 EXPR1 STR2 EXPR2 STR3." */
537 print_exprs (FILE *f, const char *str1, tree expr1, const char *str2,
538 tree expr2, const char *str3)
540 fprintf (f, "%s", str1);
541 print_generic_expr (f, expr1, TDF_SLIM);
542 fprintf (f, "%s", str2);
543 print_generic_expr (f, expr2, TDF_SLIM);
544 fprintf (f, "%s", str3);
548 /* Shortcut routine to print abnormal edge messages to file F of the form:
549 "STR1 EXPR1 STR2 EXPR2 across edge E. */
552 print_exprs_edge (FILE *f, edge e, const char *str1, tree expr1,
553 const char *str2, tree expr2)
555 print_exprs (f, str1, expr1, str2, expr2, " across an abnormal edge");
556 fprintf (f, " from BB%d->BB%d\n", e->src->index,
561 /* Coalesce partitions in MAP which are live across abnormal edges in GRAPH.
562 RV is the root variable groupings of the partitions in MAP. Since code
563 cannot be inserted on these edges, failure to coalesce something across
564 an abnormal edge is an error. */
567 coalesce_abnormal_edges (var_map map, conflict_graph graph, root_var_p rv)
575 /* Code cannot be inserted on abnormal edges. Look for all abnormal
576 edges, and coalesce any PHI results with their arguments across
580 FOR_EACH_EDGE (e, ei, bb->succs)
581 if (e->dest != EXIT_BLOCK_PTR && e->flags & EDGE_ABNORMAL)
582 for (phi = phi_nodes (e->dest); phi; phi = PHI_CHAIN (phi))
584 /* Visit each PHI on the destination side of this abnormal
585 edge, and attempt to coalesce the argument with the result. */
586 var = PHI_RESULT (phi);
587 x = var_to_partition (map, var);
589 /* Ignore results which are not relevant. */
590 if (x == NO_PARTITION)
593 tmp = PHI_ARG_DEF (phi, e->dest_idx);
594 #ifdef ENABLE_CHECKING
595 if (!phi_ssa_name_p (tmp))
597 print_exprs_edge (stderr, e,
598 "\nConstant argument in PHI. Can't insert :",
600 internal_error ("SSA corruption");
603 gcc_assert (phi_ssa_name_p (tmp));
605 y = var_to_partition (map, tmp);
606 gcc_assert (x != NO_PARTITION);
607 gcc_assert (y != NO_PARTITION);
608 #ifdef ENABLE_CHECKING
609 if (root_var_find (rv, x) != root_var_find (rv, y))
611 print_exprs_edge (stderr, e, "\nDifferent root vars: ",
612 root_var (rv, root_var_find (rv, x)),
614 root_var (rv, root_var_find (rv, y)));
615 internal_error ("SSA corruption");
618 gcc_assert (root_var_find (rv, x) == root_var_find (rv, y));
623 #ifdef ENABLE_CHECKING
624 if (conflict_graph_conflict_p (graph, x, y))
626 print_exprs_edge (stderr, e, "\n Conflict ",
627 partition_to_var (map, x),
628 " and ", partition_to_var (map, y));
629 internal_error ("SSA corruption");
632 gcc_assert (!conflict_graph_conflict_p (graph, x, y));
635 /* Now map the partitions back to their real variables. */
636 var = partition_to_var (map, x);
637 tmp = partition_to_var (map, y);
638 if (dump_file && (dump_flags & TDF_DETAILS))
640 print_exprs_edge (dump_file, e,
641 "ABNORMAL: Coalescing ",
644 #ifdef ENABLE_CHECKING
645 if (var_union (map, var, tmp) == NO_PARTITION)
647 print_exprs_edge (stderr, e, "\nUnable to coalesce",
648 partition_to_var (map, x), " and ",
649 partition_to_var (map, y));
650 internal_error ("SSA corruption");
653 gcc_assert (var_union (map, var, tmp) != NO_PARTITION);
655 conflict_graph_merge_regs (graph, x, y);
661 /* Reduce the number of live ranges in MAP. Live range information is
662 returned if FLAGS indicates that we are combining temporaries, otherwise
663 NULL is returned. The only partitions which are associated with actual
664 variables at this point are those which are forced to be coalesced for
665 various reason. (live on entry, live across abnormal edges, etc.). */
667 static tree_live_info_p
668 coalesce_ssa_name (var_map map, int flags)
674 tree_live_info_p liveinfo;
676 conflict_graph graph;
678 coalesce_list_p cl = NULL;
680 if (num_var_partitions (map) <= 1)
683 /* If no preference given, use cheap coalescing of all partitions. */
684 if ((flags & (SSANORM_COALESCE_PARTITIONS | SSANORM_USE_COALESCE_LIST)) == 0)
685 flags |= SSANORM_COALESCE_PARTITIONS;
687 liveinfo = calculate_live_on_entry (map);
688 calculate_live_on_exit (liveinfo);
689 rv = root_var_init (map);
691 /* Remove single element variable from the list. */
692 root_var_compact (rv);
694 if (flags & SSANORM_USE_COALESCE_LIST)
696 cl = create_coalesce_list (map);
698 /* Add all potential copies via PHI arguments to the list. */
701 for (phi = phi_nodes (bb); phi; phi = PHI_CHAIN (phi))
703 tree res = PHI_RESULT (phi);
704 int p = var_to_partition (map, res);
705 if (p == NO_PARTITION)
707 for (x = 0; x < (unsigned)PHI_NUM_ARGS (phi); x++)
709 tree arg = PHI_ARG_DEF (phi, x);
712 if (TREE_CODE (arg) != SSA_NAME)
714 if (SSA_NAME_VAR (res) != SSA_NAME_VAR (arg))
716 p2 = var_to_partition (map, PHI_ARG_DEF (phi, x));
717 if (p2 != NO_PARTITION)
718 add_coalesce (cl, p, p2, 1);
723 /* Coalesce all the result decls together. */
726 for (x = 0; x < num_var_partitions (map); x++)
728 tree p = partition_to_var (map, x);
729 if (TREE_CODE (SSA_NAME_VAR(p)) == RESULT_DECL)
731 if (var == NULL_TREE)
737 add_coalesce (cl, i, x, 1);
742 /* Build a conflict graph. */
743 graph = build_tree_conflict_graph (liveinfo, rv, cl);
747 if (dump_file && (dump_flags & TDF_DETAILS))
749 fprintf (dump_file, "Before sorting:\n");
750 dump_coalesce_list (dump_file, cl);
753 sort_coalesce_list (cl);
755 if (dump_file && (dump_flags & TDF_DETAILS))
757 fprintf (dump_file, "\nAfter sorting:\n");
758 dump_coalesce_list (dump_file, cl);
762 /* Put the single element variables back in. */
763 root_var_decompact (rv);
765 /* First, coalesce all live on entry variables to their root variable.
766 This will ensure the first use is coming from the correct location. */
768 live = sbitmap_alloc (num_var_partitions (map));
771 /* Set 'live' vector to indicate live on entry partitions. */
772 num = num_var_partitions (map);
773 for (x = 0 ; x < num; x++)
775 var = partition_to_var (map, x);
776 if (default_def (SSA_NAME_VAR (var)) == var)
780 if ((flags & SSANORM_COMBINE_TEMPS) == 0)
782 delete_tree_live_info (liveinfo);
786 /* Assign root variable as partition representative for each live on entry
788 EXECUTE_IF_SET_IN_SBITMAP (live, 0, x,
790 var = root_var (rv, root_var_find (rv, x));
792 /* If these aren't already coalesced... */
793 if (partition_to_var (map, x) != var)
795 /* This root variable should have not already been assigned
796 to another partition which is not coalesced with this one. */
797 gcc_assert (!ann->out_of_ssa_tag);
799 if (dump_file && (dump_flags & TDF_DETAILS))
801 print_exprs (dump_file, "Must coalesce ",
802 partition_to_var (map, x),
803 " with the root variable ", var, ".\n");
806 change_partition_var (map, var, x);
812 /* Coalesce partitions live across abnormal edges. */
813 coalesce_abnormal_edges (map, graph, rv);
815 if (dump_file && (dump_flags & TDF_DETAILS))
816 dump_var_map (dump_file, map);
818 /* Coalesce partitions. */
819 if (flags & SSANORM_USE_COALESCE_LIST)
820 coalesce_tpa_members (rv, graph, map, cl,
821 ((dump_flags & TDF_DETAILS) ? dump_file
825 if (flags & SSANORM_COALESCE_PARTITIONS)
826 coalesce_tpa_members (rv, graph, map, NULL,
827 ((dump_flags & TDF_DETAILS) ? dump_file
830 delete_coalesce_list (cl);
831 root_var_delete (rv);
832 conflict_graph_delete (graph);
838 /* Take the ssa-name var_map MAP, and assign real variables to each
842 assign_vars (var_map map)
849 rv = root_var_init (map);
853 /* Coalescing may already have forced some partitions to their root
854 variable. Find these and tag them. */
856 num = num_var_partitions (map);
857 for (x = 0; x < num; x++)
859 var = partition_to_var (map, x);
860 if (TREE_CODE (var) != SSA_NAME)
862 /* Coalescing will already have verified that more than one
863 partition doesn't have the same root variable. Simply marked
864 the variable as assigned. */
866 ann->out_of_ssa_tag = 1;
867 if (dump_file && (dump_flags & TDF_DETAILS))
869 fprintf (dump_file, "partition %d has variable ", x);
870 print_generic_expr (dump_file, var, TDF_SLIM);
871 fprintf (dump_file, " assigned to it.\n");
877 num = root_var_num (rv);
878 for (x = 0; x < num; x++)
880 var = root_var (rv, x);
882 for (i = root_var_first_partition (rv, x);
884 i = root_var_next_partition (rv, i))
886 t = partition_to_var (map, i);
888 if (t == var || TREE_CODE (t) != SSA_NAME)
891 rep = var_to_partition (map, t);
893 if (!ann->out_of_ssa_tag)
895 if (dump_file && (dump_flags & TDF_DETAILS))
896 print_exprs (dump_file, "", t, " --> ", var, "\n");
897 change_partition_var (map, var, rep);
901 if (dump_file && (dump_flags & TDF_DETAILS))
902 print_exprs (dump_file, "", t, " not coalesced with ", var,
905 var = create_temp (t);
906 change_partition_var (map, var, rep);
909 if (dump_file && (dump_flags & TDF_DETAILS))
911 fprintf (dump_file, " --> New temp: '");
912 print_generic_expr (dump_file, var, TDF_SLIM);
913 fprintf (dump_file, "'\n");
918 root_var_delete (rv);
922 /* Replace use operand P with whatever variable it has been rewritten to based
923 on the partitions in MAP. EXPR is an optional expression vector over SSA
924 versions which is used to replace P with an expression instead of a variable.
925 If the stmt is changed, return true. */
928 replace_use_variable (var_map map, use_operand_p p, tree *expr)
931 tree var = USE_FROM_PTR (p);
933 /* Check if we are replacing this variable with an expression. */
936 int version = SSA_NAME_VERSION (var);
939 tree new_expr = TREE_OPERAND (expr[version], 1);
940 SET_USE (p, new_expr);
941 /* Clear the stmt's RHS, or GC might bite us. */
942 TREE_OPERAND (expr[version], 1) = NULL_TREE;
947 new_var = var_to_partition_to_var (map, var);
950 SET_USE (p, new_var);
951 set_is_used (new_var);
958 /* Replace def operand DEF_P with whatever variable it has been rewritten to
959 based on the partitions in MAP. EXPR is an optional expression vector over
960 SSA versions which is used to replace DEF_P with an expression instead of a
961 variable. If the stmt is changed, return true. */
964 replace_def_variable (var_map map, def_operand_p def_p, tree *expr)
967 tree var = DEF_FROM_PTR (def_p);
969 /* Check if we are replacing this variable with an expression. */
972 int version = SSA_NAME_VERSION (var);
975 tree new_expr = TREE_OPERAND (expr[version], 1);
976 SET_DEF (def_p, new_expr);
977 /* Clear the stmt's RHS, or GC might bite us. */
978 TREE_OPERAND (expr[version], 1) = NULL_TREE;
983 new_var = var_to_partition_to_var (map, var);
986 SET_DEF (def_p, new_var);
987 set_is_used (new_var);
994 /* Remove any PHI node which is a virtual PHI. */
997 eliminate_virtual_phis (void)
1004 for (phi = phi_nodes (bb); phi; phi = next)
1006 next = PHI_CHAIN (phi);
1007 if (!is_gimple_reg (SSA_NAME_VAR (PHI_RESULT (phi))))
1009 #ifdef ENABLE_CHECKING
1011 /* There should be no arguments of this PHI which are in
1012 the partition list, or we get incorrect results. */
1013 for (i = 0; i < PHI_NUM_ARGS (phi); i++)
1015 tree arg = PHI_ARG_DEF (phi, i);
1016 if (TREE_CODE (arg) == SSA_NAME
1017 && is_gimple_reg (SSA_NAME_VAR (arg)))
1019 fprintf (stderr, "Argument of PHI is not virtual (");
1020 print_generic_expr (stderr, arg, TDF_SLIM);
1021 fprintf (stderr, "), but the result is :");
1022 print_generic_stmt (stderr, phi, TDF_SLIM);
1023 internal_error ("SSA corruption");
1027 remove_phi_node (phi, NULL_TREE, bb);
1034 /* This routine will coalesce variables in MAP of the same type which do not
1035 interfere with each other. LIVEINFO is the live range info for variables
1036 of interest. This will both reduce the memory footprint of the stack, and
1037 allow us to coalesce together local copies of globals and scalarized
1041 coalesce_vars (var_map map, tree_live_info_p liveinfo)
1048 conflict_graph graph;
1050 cl = create_coalesce_list (map);
1052 /* Merge all the live on entry vectors for coalesced partitions. */
1053 for (x = 0; x < num_var_partitions (map); x++)
1055 var = partition_to_var (map, x);
1056 p = var_to_partition (map, var);
1058 live_merge_and_clear (liveinfo, p, x);
1061 /* When PHI nodes are turned into copies, the result of each PHI node
1062 becomes live on entry to the block. Mark these now. */
1068 for (phi = phi_nodes (bb); phi; phi = PHI_CHAIN (phi))
1070 p = var_to_partition (map, PHI_RESULT (phi));
1072 /* Skip virtual PHI nodes. */
1073 if (p == (unsigned)NO_PARTITION)
1076 make_live_on_entry (liveinfo, bb, p);
1078 /* Each argument is a potential copy operation. Add any arguments
1079 which are not coalesced to the result to the coalesce list. */
1080 for (x = 0; x < (unsigned)PHI_NUM_ARGS (phi); x++)
1082 arg = PHI_ARG_DEF (phi, x);
1083 if (!phi_ssa_name_p (arg))
1085 p2 = var_to_partition (map, arg);
1086 if (p2 == (unsigned)NO_PARTITION)
1089 add_coalesce (cl, p, p2, 1);
1095 /* Re-calculate live on exit info. */
1096 calculate_live_on_exit (liveinfo);
1098 if (dump_file && (dump_flags & TDF_DETAILS))
1100 fprintf (dump_file, "Live range info for variable memory coalescing.\n");
1101 dump_live_info (dump_file, liveinfo, LIVEDUMP_ALL);
1103 fprintf (dump_file, "Coalesce list from phi nodes:\n");
1104 dump_coalesce_list (dump_file, cl);
1108 tv = type_var_init (map);
1110 type_var_dump (dump_file, tv);
1111 type_var_compact (tv);
1113 type_var_dump (dump_file, tv);
1115 graph = build_tree_conflict_graph (liveinfo, tv, cl);
1117 type_var_decompact (tv);
1118 if (dump_file && (dump_flags & TDF_DETAILS))
1120 fprintf (dump_file, "type var list now looks like:n");
1121 type_var_dump (dump_file, tv);
1123 fprintf (dump_file, "Coalesce list after conflict graph build:\n");
1124 dump_coalesce_list (dump_file, cl);
1127 sort_coalesce_list (cl);
1128 if (dump_file && (dump_flags & TDF_DETAILS))
1130 fprintf (dump_file, "Coalesce list after sorting:\n");
1131 dump_coalesce_list (dump_file, cl);
1134 coalesce_tpa_members (tv, graph, map, cl,
1135 ((dump_flags & TDF_DETAILS) ? dump_file : NULL));
1137 type_var_delete (tv);
1138 delete_coalesce_list (cl);
1142 /* Temporary Expression Replacement (TER)
1144 Replace SSA version variables during out-of-ssa with their defining
1145 expression if there is only one use of the variable.
1147 A pass is made through the function, one block at a time. No cross block
1148 information is tracked.
1150 Variables which only have one use, and whose defining stmt is considered
1151 a replaceable expression (see check_replaceable) are entered into
1152 consideration by adding a list of dependent partitions to the version_info
1153 vector for that ssa_name_version. This information comes from the partition
1154 mapping for each USE. At the same time, the partition_dep_list vector for
1155 these partitions have this version number entered into their lists.
1157 When the use of a replaceable ssa_variable is encountered, the dependence
1158 list in version_info[] is moved to the "pending_dependence" list in case
1159 the current expression is also replaceable. (To be determined later in
1160 processing this stmt.) version_info[] for the version is then updated to
1161 point to the defining stmt and the 'replaceable' bit is set.
1163 Any partition which is defined by a statement 'kills' any expression which
1164 is dependent on this partition. Every ssa version in the partitions'
1165 dependence list is removed from future consideration.
1167 All virtual references are lumped together. Any expression which is
1168 dependent on any virtual variable (via a VUSE) has a dependence added
1169 to the special partition defined by VIRTUAL_PARTITION.
1171 Whenever a V_MAY_DEF is seen, all expressions dependent this
1172 VIRTUAL_PARTITION are removed from consideration.
1174 At the end of a basic block, all expression are removed from consideration
1175 in preparation for the next block.
1177 The end result is a vector over SSA_NAME_VERSION which is passed back to
1178 rewrite_out_of_ssa. As the SSA variables are being rewritten, instead of
1179 replacing the SSA_NAME tree element with the partition it was assigned,
1180 it is replaced with the RHS of the defining expression. */
1183 /* Dependency list element. This can contain either a partition index or a
1184 version number, depending on which list it is in. */
1186 typedef struct value_expr_d
1189 struct value_expr_d *next;
1193 /* Temporary Expression Replacement (TER) table information. */
1195 typedef struct temp_expr_table_d
1198 void **version_info;
1199 value_expr_p *partition_dep_list;
1201 bool saw_replaceable;
1202 int virtual_partition;
1203 bitmap partition_in_use;
1204 value_expr_p free_list;
1205 value_expr_p pending_dependence;
1206 } *temp_expr_table_p;
1208 /* Used to indicate a dependency on V_MAY_DEFs. */
1209 #define VIRTUAL_PARTITION(table) (table->virtual_partition)
1211 static temp_expr_table_p new_temp_expr_table (var_map);
1212 static tree *free_temp_expr_table (temp_expr_table_p);
1213 static inline value_expr_p new_value_expr (temp_expr_table_p);
1214 static inline void free_value_expr (temp_expr_table_p, value_expr_p);
1215 static inline value_expr_p find_value_in_list (value_expr_p, int,
1217 static inline void add_value_to_list (temp_expr_table_p, value_expr_p *, int);
1218 static inline void add_info_to_list (temp_expr_table_p, value_expr_p *,
1220 static value_expr_p remove_value_from_list (value_expr_p *, int);
1221 static void add_dependance (temp_expr_table_p, int, tree);
1222 static bool check_replaceable (temp_expr_table_p, tree);
1223 static void finish_expr (temp_expr_table_p, int, bool);
1224 static void mark_replaceable (temp_expr_table_p, tree);
1225 static inline void kill_expr (temp_expr_table_p, int, bool);
1226 static inline void kill_virtual_exprs (temp_expr_table_p, bool);
1227 static void find_replaceable_in_bb (temp_expr_table_p, basic_block);
1228 static tree *find_replaceable_exprs (var_map);
1229 static void dump_replaceable_exprs (FILE *, tree *);
1232 /* Create a new TER table for MAP. */
1234 static temp_expr_table_p
1235 new_temp_expr_table (var_map map)
1237 temp_expr_table_p t;
1239 t = (temp_expr_table_p) xmalloc (sizeof (struct temp_expr_table_d));
1242 t->version_info = xcalloc (num_ssa_names + 1, sizeof (void *));
1243 t->partition_dep_list = xcalloc (num_var_partitions (map) + 1,
1244 sizeof (value_expr_p));
1246 t->replaceable = BITMAP_XMALLOC ();
1247 t->partition_in_use = BITMAP_XMALLOC ();
1249 t->saw_replaceable = false;
1250 t->virtual_partition = num_var_partitions (map);
1251 t->free_list = NULL;
1252 t->pending_dependence = NULL;
1258 /* Free TER table T. If there are valid replacements, return the expression
1262 free_temp_expr_table (temp_expr_table_p t)
1267 #ifdef ENABLE_CHECKING
1269 for (x = 0; x <= num_var_partitions (t->map); x++)
1270 gcc_assert (!t->partition_dep_list[x]);
1273 while ((p = t->free_list))
1275 t->free_list = p->next;
1279 BITMAP_XFREE (t->partition_in_use);
1280 BITMAP_XFREE (t->replaceable);
1282 free (t->partition_dep_list);
1283 if (t->saw_replaceable)
1284 ret = (tree *)t->version_info;
1286 free (t->version_info);
1293 /* Allocate a new value list node. Take it from the free list in TABLE if
1296 static inline value_expr_p
1297 new_value_expr (temp_expr_table_p table)
1300 if (table->free_list)
1302 p = table->free_list;
1303 table->free_list = p->next;
1306 p = (value_expr_p) xmalloc (sizeof (struct value_expr_d));
1312 /* Add value list node P to the free list in TABLE. */
1315 free_value_expr (temp_expr_table_p table, value_expr_p p)
1317 p->next = table->free_list;
1318 table->free_list = p;
1322 /* Find VALUE if it's in LIST. Return a pointer to the list object if found,
1323 else return NULL. If LAST_PTR is provided, it will point to the previous
1324 item upon return, or NULL if this is the first item in the list. */
1326 static inline value_expr_p
1327 find_value_in_list (value_expr_p list, int value, value_expr_p *last_ptr)
1330 value_expr_p last = NULL;
1332 for (curr = list; curr; last = curr, curr = curr->next)
1334 if (curr->value == value)
1343 /* Add VALUE to LIST, if it isn't already present. TAB is the expression
1347 add_value_to_list (temp_expr_table_p tab, value_expr_p *list, int value)
1351 if (!find_value_in_list (*list, value, NULL))
1353 info = new_value_expr (tab);
1354 info->value = value;
1361 /* Add value node INFO if it's value isn't already in LIST. Free INFO if
1362 it is already in the list. TAB is the expression table. */
1365 add_info_to_list (temp_expr_table_p tab, value_expr_p *list, value_expr_p info)
1367 if (find_value_in_list (*list, info->value, NULL))
1368 free_value_expr (tab, info);
1377 /* Look for VALUE in LIST. If found, remove it from the list and return it's
1381 remove_value_from_list (value_expr_p *list, int value)
1383 value_expr_p info, last;
1385 info = find_value_in_list (*list, value, &last);
1391 last->next = info->next;
1397 /* Add a dependency between the def of ssa VERSION and VAR. If VAR is
1398 replaceable by an expression, add a dependence each of the elements of the
1399 expression. These are contained in the pending list. TAB is the
1400 expression table. */
1403 add_dependance (temp_expr_table_p tab, int version, tree var)
1408 i = SSA_NAME_VERSION (var);
1409 if (bitmap_bit_p (tab->replaceable, i))
1411 /* This variable is being substituted, so use whatever dependences
1412 were queued up when we marked this as replaceable earlier. */
1413 while ((info = tab->pending_dependence))
1415 tab->pending_dependence = info->next;
1416 /* Get the partition this variable was dependent on. Reuse this
1417 object to represent the current expression instead. */
1419 info->value = version;
1420 add_info_to_list (tab, &(tab->partition_dep_list[x]), info);
1421 add_value_to_list (tab,
1422 (value_expr_p *)&(tab->version_info[version]), x);
1423 bitmap_set_bit (tab->partition_in_use, x);
1428 i = var_to_partition (tab->map, var);
1429 gcc_assert (i != NO_PARTITION);
1430 add_value_to_list (tab, &(tab->partition_dep_list[i]), version);
1431 add_value_to_list (tab,
1432 (value_expr_p *)&(tab->version_info[version]), i);
1433 bitmap_set_bit (tab->partition_in_use, i);
1438 /* Check if expression STMT is suitable for replacement in table TAB. If so,
1439 create an expression entry. Return true if this stmt is replaceable. */
1442 check_replaceable (temp_expr_table_p tab, tree stmt)
1445 vuse_optype vuseops;
1449 int num_use_ops, version;
1450 var_map map = tab->map;
1453 if (TREE_CODE (stmt) != MODIFY_EXPR)
1456 ann = stmt_ann (stmt);
1457 defs = DEF_OPS (ann);
1459 /* Punt if there is more than 1 def, or more than 1 use. */
1460 if (NUM_DEFS (defs) != 1)
1462 def = DEF_OP (defs, 0);
1463 if (version_ref_count (map, def) != 1)
1466 /* There must be no V_MAY_DEFS. */
1467 if (NUM_V_MAY_DEFS (V_MAY_DEF_OPS (ann)) != 0)
1470 /* There must be no V_MUST_DEFS. */
1471 if (NUM_V_MUST_DEFS (V_MUST_DEF_OPS (ann)) != 0)
1474 /* Float expressions must go through memory if float-store is on. */
1475 if (flag_float_store && FLOAT_TYPE_P (TREE_TYPE (TREE_OPERAND (stmt, 1))))
1478 uses = USE_OPS (ann);
1479 num_use_ops = NUM_USES (uses);
1480 vuseops = VUSE_OPS (ann);
1482 /* Any expression which has no virtual operands and no real operands
1483 should have been propagated if it's possible to do anything with them.
1484 If this happens here, it probably exists that way for a reason, so we
1485 won't touch it. An example is:
1487 There are no virtual uses nor any real uses, so we just leave this
1488 alone to be safe. */
1490 if (num_use_ops == 0 && NUM_VUSES (vuseops) == 0)
1493 version = SSA_NAME_VERSION (def);
1495 /* Add this expression to the dependency list for each use partition. */
1496 FOR_EACH_SSA_TREE_OPERAND (var, stmt, iter, SSA_OP_USE)
1498 add_dependance (tab, version, var);
1501 /* If there are VUSES, add a dependence on virtual defs. */
1502 if (NUM_VUSES (vuseops) != 0)
1504 add_value_to_list (tab, (value_expr_p *)&(tab->version_info[version]),
1505 VIRTUAL_PARTITION (tab));
1506 add_value_to_list (tab,
1507 &(tab->partition_dep_list[VIRTUAL_PARTITION (tab)]),
1509 bitmap_set_bit (tab->partition_in_use, VIRTUAL_PARTITION (tab));
1516 /* This function will remove the expression for VERSION from replacement
1517 consideration.n table TAB If 'replace' is true, it is marked as
1518 replaceable, otherwise not. */
1521 finish_expr (temp_expr_table_p tab, int version, bool replace)
1523 value_expr_p info, tmp;
1526 /* Remove this expression from its dependent lists. The partition dependence
1527 list is retained and transfered later to whomever uses this version. */
1528 for (info = (value_expr_p) tab->version_info[version]; info; info = tmp)
1530 partition = info->value;
1531 gcc_assert (tab->partition_dep_list[partition]);
1532 tmp = remove_value_from_list (&(tab->partition_dep_list[partition]),
1535 free_value_expr (tab, tmp);
1536 /* Only clear the bit when the dependency list is emptied via
1537 a replacement. Otherwise kill_expr will take care of it. */
1538 if (!(tab->partition_dep_list[partition]) && replace)
1539 bitmap_clear_bit (tab->partition_in_use, partition);
1542 free_value_expr (tab, info);
1547 tab->saw_replaceable = true;
1548 bitmap_set_bit (tab->replaceable, version);
1552 gcc_assert (!bitmap_bit_p (tab->replaceable, version));
1553 tab->version_info[version] = NULL;
1558 /* Mark the expression associated with VAR as replaceable, and enter
1559 the defining stmt into the version_info table TAB. */
1562 mark_replaceable (temp_expr_table_p tab, tree var)
1565 int version = SSA_NAME_VERSION (var);
1566 finish_expr (tab, version, true);
1568 /* Move the dependence list to the pending list. */
1569 if (tab->version_info[version])
1571 info = (value_expr_p) tab->version_info[version];
1572 for ( ; info->next; info = info->next)
1574 info->next = tab->pending_dependence;
1575 tab->pending_dependence = (value_expr_p)tab->version_info[version];
1578 tab->version_info[version] = SSA_NAME_DEF_STMT (var);
1582 /* This function marks any expression in TAB which is dependent on PARTITION
1583 as NOT replaceable. CLEAR_BIT is used to determine whether partition_in_use
1584 should have its bit cleared. Since this routine can be called within an
1585 EXECUTE_IF_SET_IN_BITMAP, the bit can't always be cleared. */
1588 kill_expr (temp_expr_table_p tab, int partition, bool clear_bit)
1592 /* Mark every active expr dependent on this var as not replaceable. */
1593 while ((ptr = tab->partition_dep_list[partition]) != NULL)
1594 finish_expr (tab, ptr->value, false);
1597 bitmap_clear_bit (tab->partition_in_use, partition);
1601 /* This function kills all expressions in TAB which are dependent on virtual
1602 DEFs. CLEAR_BIT determines whether partition_in_use gets cleared. */
1605 kill_virtual_exprs (temp_expr_table_p tab, bool clear_bit)
1607 kill_expr (tab, VIRTUAL_PARTITION (tab), clear_bit);
1611 /* This function processes basic block BB, and looks for variables which can
1612 be replaced by their expressions. Results are stored in TAB. */
1615 find_replaceable_in_bb (temp_expr_table_p tab, basic_block bb)
1617 block_stmt_iterator bsi;
1621 var_map map = tab->map;
1625 for (bsi = bsi_start (bb); !bsi_end_p (bsi); bsi_next (&bsi))
1627 stmt = bsi_stmt (bsi);
1628 ann = stmt_ann (stmt);
1630 /* Determine if this stmt finishes an existing expression. */
1631 FOR_EACH_SSA_TREE_OPERAND (def, stmt, iter, SSA_OP_USE)
1633 if (tab->version_info[SSA_NAME_VERSION (def)])
1635 /* Mark expression as replaceable unless stmt is volatile. */
1636 if (!ann->has_volatile_ops)
1637 mark_replaceable (tab, def);
1639 finish_expr (tab, SSA_NAME_VERSION (def), false);
1643 /* Next, see if this stmt kills off an active expression. */
1644 FOR_EACH_SSA_TREE_OPERAND (def, stmt, iter, SSA_OP_DEF)
1646 partition = var_to_partition (map, def);
1647 if (partition != NO_PARTITION && tab->partition_dep_list[partition])
1648 kill_expr (tab, partition, true);
1651 /* Now see if we are creating a new expression or not. */
1652 if (!ann->has_volatile_ops)
1653 check_replaceable (tab, stmt);
1655 /* Free any unused dependency lists. */
1656 while ((p = tab->pending_dependence))
1658 tab->pending_dependence = p->next;
1659 free_value_expr (tab, p);
1662 /* A V_MAY_DEF kills any expression using a virtual operand. */
1663 if (NUM_V_MAY_DEFS (V_MAY_DEF_OPS (ann)) > 0)
1664 kill_virtual_exprs (tab, true);
1666 /* A V_MUST_DEF kills any expression using a virtual operand. */
1667 if (NUM_V_MUST_DEFS (V_MUST_DEF_OPS (ann)) > 0)
1668 kill_virtual_exprs (tab, true);
1673 /* This function is the driver routine for replacement of temporary expressions
1674 in the SSA->normal phase, operating on MAP. If there are replaceable
1675 expressions, a table is returned which maps SSA versions to the
1676 expressions they should be replaced with. A NULL_TREE indicates no
1677 replacement should take place. If there are no replacements at all,
1678 NULL is returned by the function, otherwise an expression vector indexed
1679 by SSA_NAME version numbers. */
1682 find_replaceable_exprs (var_map map)
1686 temp_expr_table_p table;
1689 table = new_temp_expr_table (map);
1694 find_replaceable_in_bb (table, bb);
1695 EXECUTE_IF_SET_IN_BITMAP ((table->partition_in_use), 0, i, bi)
1697 kill_expr (table, i, false);
1701 ret = free_temp_expr_table (table);
1706 /* Dump TER expression table EXPR to file F. */
1709 dump_replaceable_exprs (FILE *f, tree *expr)
1713 fprintf (f, "\nReplacing Expressions\n");
1714 for (x = 0; x < (int)num_ssa_names + 1; x++)
1718 var = DEF_OP (STMT_DEF_OPS (stmt), 0);
1719 print_generic_expr (f, var, TDF_SLIM);
1720 fprintf (f, " replace with --> ");
1721 print_generic_expr (f, TREE_OPERAND (stmt, 1), TDF_SLIM);
1728 /* Helper function for discover_nonconstant_array_refs.
1729 Look for ARRAY_REF nodes with non-constant indexes and mark them
1733 discover_nonconstant_array_refs_r (tree * tp, int *walk_subtrees,
1734 void *data ATTRIBUTE_UNUSED)
1738 if (IS_TYPE_OR_DECL_P (t))
1740 else if (TREE_CODE (t) == ARRAY_REF || TREE_CODE (t) == ARRAY_RANGE_REF)
1742 while (((TREE_CODE (t) == ARRAY_REF || TREE_CODE (t) == ARRAY_RANGE_REF)
1743 && is_gimple_min_invariant (TREE_OPERAND (t, 1))
1744 && (!TREE_OPERAND (t, 2)
1745 || is_gimple_min_invariant (TREE_OPERAND (t, 2))))
1746 || (TREE_CODE (t) == COMPONENT_REF
1747 && (!TREE_OPERAND (t,2)
1748 || is_gimple_min_invariant (TREE_OPERAND (t, 2))))
1749 || TREE_CODE (t) == BIT_FIELD_REF
1750 || TREE_CODE (t) == REALPART_EXPR
1751 || TREE_CODE (t) == IMAGPART_EXPR
1752 || TREE_CODE (t) == VIEW_CONVERT_EXPR
1753 || TREE_CODE (t) == NOP_EXPR
1754 || TREE_CODE (t) == CONVERT_EXPR)
1755 t = TREE_OPERAND (t, 0);
1757 if (TREE_CODE (t) == ARRAY_REF || TREE_CODE (t) == ARRAY_RANGE_REF)
1759 t = get_base_address (t);
1760 if (t && DECL_P (t))
1761 TREE_ADDRESSABLE (t) = 1;
1771 /* RTL expansion is not able to compile array references with variable
1772 offsets for arrays stored in single register. Discover such
1773 expressions and mark variables as addressable to avoid this
1777 discover_nonconstant_array_refs (void)
1780 block_stmt_iterator bsi;
1784 for (bsi = bsi_start (bb); !bsi_end_p (bsi); bsi_next (&bsi))
1785 walk_tree (bsi_stmt_ptr (bsi), discover_nonconstant_array_refs_r,
1791 /* This function will rewrite the current program using the variable mapping
1792 found in MAP. If the replacement vector VALUES is provided, any
1793 occurrences of partitions with non-null entries in the vector will be
1794 replaced with the expression in the vector instead of its mapped
1798 rewrite_trees (var_map map, tree *values)
1802 block_stmt_iterator si;
1807 #ifdef ENABLE_CHECKING
1808 /* Search for PHIs where the destination has no partition, but one
1809 or more arguments has a partition. This should not happen and can
1810 create incorrect code. */
1815 for (phi = phi_nodes (bb); phi; phi = PHI_CHAIN (phi))
1817 tree T0 = var_to_partition_to_var (map, PHI_RESULT (phi));
1819 if (T0 == NULL_TREE)
1823 for (i = 0; i < PHI_NUM_ARGS (phi); i++)
1825 tree arg = PHI_ARG_DEF (phi, i);
1827 if (TREE_CODE (arg) == SSA_NAME
1828 && var_to_partition (map, arg) != NO_PARTITION)
1830 fprintf (stderr, "Argument of PHI is in a partition :(");
1831 print_generic_expr (stderr, arg, TDF_SLIM);
1832 fprintf (stderr, "), but the result is not :");
1833 print_generic_stmt (stderr, phi, TDF_SLIM);
1834 internal_error ("SSA corruption");
1842 /* Replace PHI nodes with any required copies. */
1843 g = new_elim_graph (map->num_partitions);
1847 for (si = bsi_start (bb); !bsi_end_p (si); )
1849 size_t num_uses, num_defs;
1852 tree stmt = bsi_stmt (si);
1853 use_operand_p use_p;
1854 def_operand_p def_p;
1855 int remove = 0, is_copy = 0;
1859 get_stmt_operands (stmt);
1860 ann = stmt_ann (stmt);
1863 if (TREE_CODE (stmt) == MODIFY_EXPR
1864 && (TREE_CODE (TREE_OPERAND (stmt, 1)) == SSA_NAME))
1867 uses = USE_OPS (ann);
1868 num_uses = NUM_USES (uses);
1869 FOR_EACH_SSA_USE_OPERAND (use_p, stmt, iter, SSA_OP_USE)
1871 if (replace_use_variable (map, use_p, values))
1875 defs = DEF_OPS (ann);
1876 num_defs = NUM_DEFS (defs);
1878 /* Mark this stmt for removal if it is the list of replaceable
1880 if (values && num_defs == 1)
1882 tree def = DEF_OP (defs, 0);
1884 val = values[SSA_NAME_VERSION (def)];
1890 FOR_EACH_SSA_DEF_OPERAND (def_p, stmt, iter, SSA_OP_DEF)
1892 if (replace_def_variable (map, def_p, NULL))
1895 /* If both SSA_NAMEs coalesce to the same variable,
1896 mark the now redundant copy for removal. */
1899 && (DEF_FROM_PTR (def_p) == USE_OP (uses, 0)))
1902 if (changed & !remove)
1906 /* Remove any stmts marked for removal. */
1913 phi = phi_nodes (bb);
1917 FOR_EACH_EDGE (e, ei, bb->preds)
1918 eliminate_phi (e, g);
1922 delete_elim_graph (g);
1926 /* These are the local work structures used to determine the best place to
1927 insert the copies that were placed on edges by the SSA->normal pass.. */
1928 static varray_type edge_leader = NULL;
1929 static varray_type GTY(()) stmt_list = NULL;
1930 static bitmap leader_has_match = NULL;
1931 static edge leader_match = NULL;
1934 /* Pass this function to make_forwarder_block so that all the edges with
1935 matching PENDING_STMT lists to 'curr_stmt_list' get redirected. */
1937 same_stmt_list_p (edge e)
1939 return (e->aux == (PTR) leader_match) ? true : false;
1943 /* Return TRUE if S1 and S2 are equivalent copies. */
1945 identical_copies_p (tree s1, tree s2)
1947 #ifdef ENABLE_CHECKING
1948 gcc_assert (TREE_CODE (s1) == MODIFY_EXPR);
1949 gcc_assert (TREE_CODE (s2) == MODIFY_EXPR);
1950 gcc_assert (DECL_P (TREE_OPERAND (s1, 0)));
1951 gcc_assert (DECL_P (TREE_OPERAND (s2, 0)));
1954 if (TREE_OPERAND (s1, 0) != TREE_OPERAND (s2, 0))
1957 s1 = TREE_OPERAND (s1, 1);
1958 s2 = TREE_OPERAND (s2, 1);
1967 /* Compare the PENDING_STMT list for two edges, and return true if the lists
1968 contain the same sequence of copies. */
1971 identical_stmt_lists_p (edge e1, edge e2)
1973 tree t1 = PENDING_STMT (e1);
1974 tree t2 = PENDING_STMT (e2);
1975 tree_stmt_iterator tsi1, tsi2;
1977 gcc_assert (TREE_CODE (t1) == STATEMENT_LIST);
1978 gcc_assert (TREE_CODE (t2) == STATEMENT_LIST);
1980 for (tsi1 = tsi_start (t1), tsi2 = tsi_start (t2);
1981 !tsi_end_p (tsi1) && !tsi_end_p (tsi2);
1982 tsi_next (&tsi1), tsi_next (&tsi2))
1984 if (!identical_copies_p (tsi_stmt (tsi1), tsi_stmt (tsi2)))
1988 if (!tsi_end_p (tsi1) || ! tsi_end_p (tsi2))
1995 /* Look at all the incoming edges to block BB, and decide where the best place
1996 to insert the stmts on each edge are, and perform those insertions. Output
1997 any debug information to DEBUG_FILE. Return true if anything other than a
1998 standard edge insertion is done. */
2001 analyze_edges_for_bb (basic_block bb, FILE *debug_file)
2007 bool have_opportunity;
2008 block_stmt_iterator bsi;
2010 edge single_edge = NULL;
2015 /* Blocks which contain at least one abnormal edge cannot use
2016 make_forwarder_block. Look for these blocks, and commit any PENDING_STMTs
2017 found on edges in these block. */
2018 have_opportunity = true;
2019 FOR_EACH_EDGE (e, ei, bb->preds)
2020 if (e->flags & EDGE_ABNORMAL)
2022 have_opportunity = false;
2026 if (!have_opportunity)
2028 FOR_EACH_EDGE (e, ei, bb->preds)
2029 if (PENDING_STMT (e))
2030 bsi_commit_one_edge_insert (e, NULL);
2033 /* Find out how many edges there are with interesting pending stmts on them.
2034 Commit the stmts on edges we are not interested in. */
2035 FOR_EACH_EDGE (e, ei, bb->preds)
2037 if (PENDING_STMT (e))
2039 gcc_assert (!(e->flags & EDGE_ABNORMAL));
2040 if (e->flags & EDGE_FALLTHRU)
2042 bsi = bsi_start (e->src);
2043 if (!bsi_end_p (bsi))
2045 stmt = bsi_stmt (bsi);
2047 gcc_assert (stmt != NULL_TREE);
2048 is_label = (TREE_CODE (stmt) == LABEL_EXPR);
2049 /* Punt if it has non-label stmts, or isn't local. */
2050 if (!is_label || DECL_NONLOCAL (TREE_OPERAND (stmt, 0))
2051 || !bsi_end_p (bsi))
2053 bsi_commit_one_edge_insert (e, NULL);
2063 /* If there aren't at least 2 edges, no sharing will happen. */
2067 bsi_commit_one_edge_insert (single_edge, NULL);
2071 /* Ensure that we have empty worklists. */
2072 if (edge_leader == NULL)
2074 VARRAY_EDGE_INIT (edge_leader, 25, "edge_leader");
2075 VARRAY_TREE_INIT (stmt_list, 25, "stmt_list");
2076 leader_has_match = BITMAP_XMALLOC ();
2080 #ifdef ENABLE_CHECKING
2081 gcc_assert (VARRAY_ACTIVE_SIZE (edge_leader) == 0);
2082 gcc_assert (VARRAY_ACTIVE_SIZE (stmt_list) == 0);
2083 gcc_assert (bitmap_empty_p (leader_has_match));
2087 /* Find the "leader" block for each set of unique stmt lists. Preference is
2088 given to FALLTHRU blocks since they would need a GOTO to arrive at another
2089 block. The leader edge destination is the block which all the other edges
2090 with the same stmt list will be redirected to. */
2091 have_opportunity = false;
2092 FOR_EACH_EDGE (e, ei, bb->preds)
2094 if (PENDING_STMT (e))
2098 /* Look for the same stmt list in edge leaders list. */
2099 for (x = 0; x < VARRAY_ACTIVE_SIZE (edge_leader); x++)
2101 edge leader = VARRAY_EDGE (edge_leader, x);
2102 if (identical_stmt_lists_p (leader, e))
2104 /* Give this edge the same stmt list pointer. */
2105 PENDING_STMT (e) = NULL;
2107 bitmap_set_bit (leader_has_match, x);
2108 have_opportunity = found = true;
2113 /* If no similar stmt list, add this edge to the leader list. */
2116 VARRAY_PUSH_EDGE (edge_leader, e);
2117 VARRAY_PUSH_TREE (stmt_list, PENDING_STMT (e));
2122 /* If there are no similar lists, just issue the stmts. */
2123 if (!have_opportunity)
2125 for (x = 0; x < VARRAY_ACTIVE_SIZE (edge_leader); x++)
2126 bsi_commit_one_edge_insert (VARRAY_EDGE (edge_leader, x), NULL);
2127 VARRAY_POP_ALL (edge_leader);
2128 VARRAY_POP_ALL (stmt_list);
2129 bitmap_clear (leader_has_match);
2135 fprintf (debug_file, "\nOpportunities in BB %d for stmt/block reduction:\n",
2139 /* For each common list, create a forwarding block and issue the stmt's
2141 for (x = 0 ; x < VARRAY_ACTIVE_SIZE (edge_leader); x++)
2142 if (bitmap_bit_p (leader_has_match, x))
2144 edge new_edge, leader_edge;
2145 block_stmt_iterator bsi;
2146 tree curr_stmt_list;
2148 leader_match = leader_edge = VARRAY_EDGE (edge_leader, x);
2150 /* The tree_* cfg manipulation routines use the PENDING_EDGE field
2151 for various PHI manipulations, so it gets cleared whhen calls are
2152 made to make_forwarder_block(). So make sure the edge is clear,
2153 and use the saved stmt list. */
2154 PENDING_STMT (leader_edge) = NULL;
2155 leader_edge->aux = leader_edge;
2156 curr_stmt_list = VARRAY_TREE (stmt_list, x);
2158 new_edge = make_forwarder_block (leader_edge->dest, same_stmt_list_p,
2160 bb = new_edge->dest;
2163 fprintf (debug_file, "Splitting BB %d for Common stmt list. ",
2164 leader_edge->dest->index);
2165 fprintf (debug_file, "Original block is now BB%d.\n", bb->index);
2166 print_generic_stmt (debug_file, curr_stmt_list, TDF_VOPS);
2169 FOR_EACH_EDGE (e, ei, new_edge->src->preds)
2173 fprintf (debug_file, " Edge (%d->%d) lands here.\n",
2174 e->src->index, e->dest->index);
2177 bsi = bsi_last (leader_edge->dest);
2178 bsi_insert_after (&bsi, curr_stmt_list, BSI_NEW_STMT);
2180 leader_match = NULL;
2181 /* We should never get a new block now. */
2185 e = VARRAY_EDGE (edge_leader, x);
2186 PENDING_STMT (e) = VARRAY_TREE (stmt_list, x);
2187 bsi_commit_one_edge_insert (e, NULL);
2191 /* Clear the working data structures. */
2192 VARRAY_POP_ALL (edge_leader);
2193 VARRAY_POP_ALL (stmt_list);
2194 bitmap_clear (leader_has_match);
2200 /* This function will analyze the insertions which were performed on edges,
2201 and decide whether they should be left on that edge, or whether it is more
2202 efficient to emit some subset of them in a single block. All stmts are
2203 inserted somewhere, and if non-NULL, debug information is printed via
2207 perform_edge_inserts (FILE *dump_file)
2210 bool changed = false;
2213 fprintf(dump_file, "Analyzing Edge Insertions.\n");
2216 changed |= analyze_edges_for_bb (bb, dump_file);
2218 changed |= analyze_edges_for_bb (EXIT_BLOCK_PTR, dump_file);
2220 /* Clear out any tables which were created. */
2222 BITMAP_XFREE (leader_has_match);
2226 free_dominance_info (CDI_DOMINATORS);
2227 free_dominance_info (CDI_POST_DOMINATORS);
2230 #ifdef ENABLE_CHECKING
2236 FOR_EACH_EDGE (e, ei, bb->preds)
2238 if (PENDING_STMT (e))
2239 error (" Pending stmts not issued on PRED edge (%d, %d)\n",
2240 e->src->index, e->dest->index);
2242 FOR_EACH_EDGE (e, ei, bb->succs)
2244 if (PENDING_STMT (e))
2245 error (" Pending stmts not issued on SUCC edge (%d, %d)\n",
2246 e->src->index, e->dest->index);
2249 FOR_EACH_EDGE (e, ei, ENTRY_BLOCK_PTR->succs)
2251 if (PENDING_STMT (e))
2252 error (" Pending stmts not issued on ENTRY edge (%d, %d)\n",
2253 e->src->index, e->dest->index);
2255 FOR_EACH_EDGE (e, ei, EXIT_BLOCK_PTR->preds)
2257 if (PENDING_STMT (e))
2258 error (" Pending stmts not issued on EXIT edge (%d, %d)\n",
2259 e->src->index, e->dest->index);
2266 /* Remove the variables specified in MAP from SSA form. Any debug information
2267 is sent to DUMP. FLAGS indicate what options should be used. */
2270 remove_ssa_form (FILE *dump, var_map map, int flags)
2272 tree_live_info_p liveinfo;
2276 tree *values = NULL;
2281 /* If we are not combining temps, don't calculate live ranges for variables
2282 with only one SSA version. */
2283 if ((flags & SSANORM_COMBINE_TEMPS) == 0)
2284 compact_var_map (map, VARMAP_NO_SINGLE_DEFS);
2286 compact_var_map (map, VARMAP_NORMAL);
2288 if (dump_file && (dump_flags & TDF_DETAILS))
2289 dump_var_map (dump_file, map);
2291 liveinfo = coalesce_ssa_name (map, flags);
2293 /* Make sure even single occurrence variables are in the list now. */
2294 if ((flags & SSANORM_COMBINE_TEMPS) == 0)
2295 compact_var_map (map, VARMAP_NORMAL);
2297 if (dump_file && (dump_flags & TDF_DETAILS))
2299 fprintf (dump_file, "After Coalescing:\n");
2300 dump_var_map (dump_file, map);
2303 if (flags & SSANORM_PERFORM_TER)
2305 values = find_replaceable_exprs (map);
2306 if (values && dump_file && (dump_flags & TDF_DETAILS))
2307 dump_replaceable_exprs (dump_file, values);
2310 /* Assign real variables to the partitions now. */
2313 if (dump_file && (dump_flags & TDF_DETAILS))
2315 fprintf (dump_file, "After Root variable replacement:\n");
2316 dump_var_map (dump_file, map);
2319 if ((flags & SSANORM_COMBINE_TEMPS) && liveinfo)
2321 coalesce_vars (map, liveinfo);
2322 if (dump_file && (dump_flags & TDF_DETAILS))
2324 fprintf (dump_file, "After variable memory coalescing:\n");
2325 dump_var_map (dump_file, map);
2330 delete_tree_live_info (liveinfo);
2332 rewrite_trees (map, values);
2337 /* Remove phi nodes which have been translated back to real variables. */
2340 for (phi = phi_nodes (bb); phi; phi = next)
2342 next = PHI_CHAIN (phi);
2343 if ((flags & SSANORM_REMOVE_ALL_PHIS)
2344 || var_to_partition (map, PHI_RESULT (phi)) != NO_PARTITION)
2345 remove_phi_node (phi, NULL_TREE, bb);
2349 /* If any copies were inserted on edges, analyze and insert them now. */
2350 perform_edge_inserts (dump_file);
2355 /* Take the current function out of SSA form, as described in
2356 R. Morgan, ``Building an Optimizing Compiler'',
2357 Butterworth-Heinemann, Boston, MA, 1998. pp 176-186. */
2360 rewrite_out_of_ssa (void)
2364 int ssa_flags = (SSANORM_REMOVE_ALL_PHIS | SSANORM_USE_COALESCE_LIST);
2366 if (!flag_tree_live_range_split)
2367 ssa_flags |= SSANORM_COALESCE_PARTITIONS;
2369 eliminate_virtual_phis ();
2371 if (dump_file && (dump_flags & TDF_DETAILS))
2372 dump_tree_cfg (dump_file, dump_flags & ~TDF_DETAILS);
2374 /* We cannot allow unssa to un-gimplify trees before we instrument them. */
2375 if (flag_tree_ter && !flag_mudflap)
2376 var_flags = SSA_VAR_MAP_REF_COUNT;
2378 map = create_ssa_var_map (var_flags);
2380 if (flag_tree_combine_temps)
2381 ssa_flags |= SSANORM_COMBINE_TEMPS;
2382 if (flag_tree_ter && !flag_mudflap)
2383 ssa_flags |= SSANORM_PERFORM_TER;
2385 remove_ssa_form (dump_file, map, ssa_flags);
2387 if (dump_file && (dump_flags & TDF_DETAILS))
2388 dump_tree_cfg (dump_file, dump_flags & ~TDF_DETAILS);
2390 /* Do some cleanups which reduce the amount of data the
2391 tree->rtl expanders deal with. */
2392 cfg_remove_useless_stmts ();
2394 /* Flush out flow graph and SSA data. */
2395 delete_var_map (map);
2397 /* Mark arrays indexed with non-constant indices with TREE_ADDRESSABLE. */
2398 discover_nonconstant_array_refs ();
2402 /* Define the parameters of the out of SSA pass. */
2404 struct tree_opt_pass pass_del_ssa =
2406 "optimized", /* name */
2408 rewrite_out_of_ssa, /* execute */
2411 0, /* static_pass_number */
2412 TV_TREE_SSA_TO_NORMAL, /* tv_id */
2413 PROP_cfg | PROP_ssa | PROP_alias, /* properties_required */
2414 0, /* properties_provided */
2415 /* ??? If TER is enabled, we also kill gimple. */
2416 PROP_ssa, /* properties_destroyed */
2417 TODO_verify_ssa | TODO_verify_flow
2418 | TODO_verify_stmts, /* todo_flags_start */
2419 TODO_dump_func | TODO_ggc_collect, /* todo_flags_finish */