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 y = phi_arg_from_edge (phi, e);
594 gcc_assert (y != -1);
596 tmp = PHI_ARG_DEF (phi, y);
597 #ifdef ENABLE_CHECKING
598 if (!phi_ssa_name_p (tmp))
600 print_exprs_edge (stderr, e,
601 "\nConstant argument in PHI. Can't insert :",
603 internal_error ("SSA corruption");
606 gcc_assert (phi_ssa_name_p (tmp));
608 y = var_to_partition (map, tmp);
609 gcc_assert (x != NO_PARTITION);
610 gcc_assert (y != NO_PARTITION);
611 #ifdef ENABLE_CHECKING
612 if (root_var_find (rv, x) != root_var_find (rv, y))
614 print_exprs_edge (stderr, e, "\nDifferent root vars: ",
615 root_var (rv, root_var_find (rv, x)),
617 root_var (rv, root_var_find (rv, y)));
618 internal_error ("SSA corruption");
621 gcc_assert (root_var_find (rv, x) == root_var_find (rv, y));
626 #ifdef ENABLE_CHECKING
627 if (conflict_graph_conflict_p (graph, x, y))
629 print_exprs_edge (stderr, e, "\n Conflict ",
630 partition_to_var (map, x),
631 " and ", partition_to_var (map, y));
632 internal_error ("SSA corruption");
635 gcc_assert (!conflict_graph_conflict_p (graph, x, y));
638 /* Now map the partitions back to their real variables. */
639 var = partition_to_var (map, x);
640 tmp = partition_to_var (map, y);
641 if (dump_file && (dump_flags & TDF_DETAILS))
643 print_exprs_edge (dump_file, e,
644 "ABNORMAL: Coalescing ",
647 #ifdef ENABLE_CHECKING
648 if (var_union (map, var, tmp) == NO_PARTITION)
650 print_exprs_edge (stderr, e, "\nUnable to coalesce",
651 partition_to_var (map, x), " and ",
652 partition_to_var (map, y));
653 internal_error ("SSA corruption");
656 gcc_assert (var_union (map, var, tmp) != NO_PARTITION);
658 conflict_graph_merge_regs (graph, x, y);
664 /* Reduce the number of live ranges in MAP. Live range information is
665 returned if FLAGS indicates that we are combining temporaries, otherwise
666 NULL is returned. The only partitions which are associated with actual
667 variables at this point are those which are forced to be coalesced for
668 various reason. (live on entry, live across abnormal edges, etc.). */
670 static tree_live_info_p
671 coalesce_ssa_name (var_map map, int flags)
677 tree_live_info_p liveinfo;
679 conflict_graph graph;
681 coalesce_list_p cl = NULL;
683 if (num_var_partitions (map) <= 1)
686 /* If no preference given, use cheap coalescing of all partitions. */
687 if ((flags & (SSANORM_COALESCE_PARTITIONS | SSANORM_USE_COALESCE_LIST)) == 0)
688 flags |= SSANORM_COALESCE_PARTITIONS;
690 liveinfo = calculate_live_on_entry (map);
691 calculate_live_on_exit (liveinfo);
692 rv = root_var_init (map);
694 /* Remove single element variable from the list. */
695 root_var_compact (rv);
697 if (flags & SSANORM_USE_COALESCE_LIST)
699 cl = create_coalesce_list (map);
701 /* Add all potential copies via PHI arguments to the list. */
704 for (phi = phi_nodes (bb); phi; phi = PHI_CHAIN (phi))
706 tree res = PHI_RESULT (phi);
707 int p = var_to_partition (map, res);
708 if (p == NO_PARTITION)
710 for (x = 0; x < (unsigned)PHI_NUM_ARGS (phi); x++)
712 tree arg = PHI_ARG_DEF (phi, x);
715 if (TREE_CODE (arg) != SSA_NAME)
717 if (SSA_NAME_VAR (res) != SSA_NAME_VAR (arg))
719 p2 = var_to_partition (map, PHI_ARG_DEF (phi, x));
720 if (p2 != NO_PARTITION)
721 add_coalesce (cl, p, p2, 1);
726 /* Coalesce all the result decls together. */
729 for (x = 0; x < num_var_partitions (map); x++)
731 tree p = partition_to_var (map, x);
732 if (TREE_CODE (SSA_NAME_VAR(p)) == RESULT_DECL)
734 if (var == NULL_TREE)
740 add_coalesce (cl, i, x, 1);
745 /* Build a conflict graph. */
746 graph = build_tree_conflict_graph (liveinfo, rv, cl);
750 if (dump_file && (dump_flags & TDF_DETAILS))
752 fprintf (dump_file, "Before sorting:\n");
753 dump_coalesce_list (dump_file, cl);
756 sort_coalesce_list (cl);
758 if (dump_file && (dump_flags & TDF_DETAILS))
760 fprintf (dump_file, "\nAfter sorting:\n");
761 dump_coalesce_list (dump_file, cl);
765 /* Put the single element variables back in. */
766 root_var_decompact (rv);
768 /* First, coalesce all live on entry variables to their root variable.
769 This will ensure the first use is coming from the correct location. */
771 live = sbitmap_alloc (num_var_partitions (map));
774 /* Set 'live' vector to indicate live on entry partitions. */
775 num = num_var_partitions (map);
776 for (x = 0 ; x < num; x++)
778 var = partition_to_var (map, x);
779 if (default_def (SSA_NAME_VAR (var)) == var)
783 if ((flags & SSANORM_COMBINE_TEMPS) == 0)
785 delete_tree_live_info (liveinfo);
789 /* Assign root variable as partition representative for each live on entry
791 EXECUTE_IF_SET_IN_SBITMAP (live, 0, x,
793 var = root_var (rv, root_var_find (rv, x));
795 /* If these aren't already coalesced... */
796 if (partition_to_var (map, x) != var)
798 /* This root variable should have not already been assigned
799 to another partition which is not coalesced with this one. */
800 gcc_assert (!ann->out_of_ssa_tag);
802 if (dump_file && (dump_flags & TDF_DETAILS))
804 print_exprs (dump_file, "Must coalesce ",
805 partition_to_var (map, x),
806 " with the root variable ", var, ".\n");
809 change_partition_var (map, var, x);
815 /* Coalesce partitions live across abnormal edges. */
816 coalesce_abnormal_edges (map, graph, rv);
818 if (dump_file && (dump_flags & TDF_DETAILS))
819 dump_var_map (dump_file, map);
821 /* Coalesce partitions. */
822 if (flags & SSANORM_USE_COALESCE_LIST)
823 coalesce_tpa_members (rv, graph, map, cl,
824 ((dump_flags & TDF_DETAILS) ? dump_file
828 if (flags & SSANORM_COALESCE_PARTITIONS)
829 coalesce_tpa_members (rv, graph, map, NULL,
830 ((dump_flags & TDF_DETAILS) ? dump_file
833 delete_coalesce_list (cl);
834 root_var_delete (rv);
835 conflict_graph_delete (graph);
841 /* Take the ssa-name var_map MAP, and assign real variables to each
845 assign_vars (var_map map)
852 rv = root_var_init (map);
856 /* Coalescing may already have forced some partitions to their root
857 variable. Find these and tag them. */
859 num = num_var_partitions (map);
860 for (x = 0; x < num; x++)
862 var = partition_to_var (map, x);
863 if (TREE_CODE (var) != SSA_NAME)
865 /* Coalescing will already have verified that more than one
866 partition doesn't have the same root variable. Simply marked
867 the variable as assigned. */
869 ann->out_of_ssa_tag = 1;
870 if (dump_file && (dump_flags & TDF_DETAILS))
872 fprintf (dump_file, "partition %d has variable ", x);
873 print_generic_expr (dump_file, var, TDF_SLIM);
874 fprintf (dump_file, " assigned to it.\n");
880 num = root_var_num (rv);
881 for (x = 0; x < num; x++)
883 var = root_var (rv, x);
885 for (i = root_var_first_partition (rv, x);
887 i = root_var_next_partition (rv, i))
889 t = partition_to_var (map, i);
891 if (t == var || TREE_CODE (t) != SSA_NAME)
894 rep = var_to_partition (map, t);
896 if (!ann->out_of_ssa_tag)
898 if (dump_file && (dump_flags & TDF_DETAILS))
899 print_exprs (dump_file, "", t, " --> ", var, "\n");
900 change_partition_var (map, var, rep);
904 if (dump_file && (dump_flags & TDF_DETAILS))
905 print_exprs (dump_file, "", t, " not coalesced with ", var,
908 var = create_temp (t);
909 change_partition_var (map, var, rep);
912 if (dump_file && (dump_flags & TDF_DETAILS))
914 fprintf (dump_file, " --> New temp: '");
915 print_generic_expr (dump_file, var, TDF_SLIM);
916 fprintf (dump_file, "'\n");
921 root_var_delete (rv);
925 /* Replace use operand P with whatever variable it has been rewritten to based
926 on the partitions in MAP. EXPR is an optional expression vector over SSA
927 versions which is used to replace P with an expression instead of a variable.
928 If the stmt is changed, return true. */
931 replace_use_variable (var_map map, use_operand_p p, tree *expr)
934 tree var = USE_FROM_PTR (p);
936 /* Check if we are replacing this variable with an expression. */
939 int version = SSA_NAME_VERSION (var);
942 tree new_expr = TREE_OPERAND (expr[version], 1);
943 SET_USE (p, new_expr);
944 /* Clear the stmt's RHS, or GC might bite us. */
945 TREE_OPERAND (expr[version], 1) = NULL_TREE;
950 new_var = var_to_partition_to_var (map, var);
953 SET_USE (p, new_var);
954 set_is_used (new_var);
961 /* Replace def operand DEF_P with whatever variable it has been rewritten to
962 based on the partitions in MAP. EXPR is an optional expression vector over
963 SSA versions which is used to replace DEF_P with an expression instead of a
964 variable. If the stmt is changed, return true. */
967 replace_def_variable (var_map map, def_operand_p def_p, tree *expr)
970 tree var = DEF_FROM_PTR (def_p);
972 /* Check if we are replacing this variable with an expression. */
975 int version = SSA_NAME_VERSION (var);
978 tree new_expr = TREE_OPERAND (expr[version], 1);
979 SET_DEF (def_p, new_expr);
980 /* Clear the stmt's RHS, or GC might bite us. */
981 TREE_OPERAND (expr[version], 1) = NULL_TREE;
986 new_var = var_to_partition_to_var (map, var);
989 SET_DEF (def_p, new_var);
990 set_is_used (new_var);
997 /* Remove any PHI node which is a virtual PHI. */
1000 eliminate_virtual_phis (void)
1007 for (phi = phi_nodes (bb); phi; phi = next)
1009 next = PHI_CHAIN (phi);
1010 if (!is_gimple_reg (SSA_NAME_VAR (PHI_RESULT (phi))))
1012 #ifdef ENABLE_CHECKING
1014 /* There should be no arguments of this PHI which are in
1015 the partition list, or we get incorrect results. */
1016 for (i = 0; i < PHI_NUM_ARGS (phi); i++)
1018 tree arg = PHI_ARG_DEF (phi, i);
1019 if (TREE_CODE (arg) == SSA_NAME
1020 && is_gimple_reg (SSA_NAME_VAR (arg)))
1022 fprintf (stderr, "Argument of PHI is not virtual (");
1023 print_generic_expr (stderr, arg, TDF_SLIM);
1024 fprintf (stderr, "), but the result is :");
1025 print_generic_stmt (stderr, phi, TDF_SLIM);
1026 internal_error ("SSA corruption");
1030 remove_phi_node (phi, NULL_TREE, bb);
1037 /* This routine will coalesce variables in MAP of the same type which do not
1038 interfere with each other. LIVEINFO is the live range info for variables
1039 of interest. This will both reduce the memory footprint of the stack, and
1040 allow us to coalesce together local copies of globals and scalarized
1044 coalesce_vars (var_map map, tree_live_info_p liveinfo)
1051 conflict_graph graph;
1053 cl = create_coalesce_list (map);
1055 /* Merge all the live on entry vectors for coalesced partitions. */
1056 for (x = 0; x < num_var_partitions (map); x++)
1058 var = partition_to_var (map, x);
1059 p = var_to_partition (map, var);
1061 live_merge_and_clear (liveinfo, p, x);
1064 /* When PHI nodes are turned into copies, the result of each PHI node
1065 becomes live on entry to the block. Mark these now. */
1071 for (phi = phi_nodes (bb); phi; phi = PHI_CHAIN (phi))
1073 p = var_to_partition (map, PHI_RESULT (phi));
1075 /* Skip virtual PHI nodes. */
1076 if (p == (unsigned)NO_PARTITION)
1079 make_live_on_entry (liveinfo, bb, p);
1081 /* Each argument is a potential copy operation. Add any arguments
1082 which are not coalesced to the result to the coalesce list. */
1083 for (x = 0; x < (unsigned)PHI_NUM_ARGS (phi); x++)
1085 arg = PHI_ARG_DEF (phi, x);
1086 if (!phi_ssa_name_p (arg))
1088 p2 = var_to_partition (map, arg);
1089 if (p2 == (unsigned)NO_PARTITION)
1092 add_coalesce (cl, p, p2, 1);
1098 /* Re-calculate live on exit info. */
1099 calculate_live_on_exit (liveinfo);
1101 if (dump_file && (dump_flags & TDF_DETAILS))
1103 fprintf (dump_file, "Live range info for variable memory coalescing.\n");
1104 dump_live_info (dump_file, liveinfo, LIVEDUMP_ALL);
1106 fprintf (dump_file, "Coalesce list from phi nodes:\n");
1107 dump_coalesce_list (dump_file, cl);
1111 tv = type_var_init (map);
1113 type_var_dump (dump_file, tv);
1114 type_var_compact (tv);
1116 type_var_dump (dump_file, tv);
1118 graph = build_tree_conflict_graph (liveinfo, tv, cl);
1120 type_var_decompact (tv);
1121 if (dump_file && (dump_flags & TDF_DETAILS))
1123 fprintf (dump_file, "type var list now looks like:n");
1124 type_var_dump (dump_file, tv);
1126 fprintf (dump_file, "Coalesce list after conflict graph build:\n");
1127 dump_coalesce_list (dump_file, cl);
1130 sort_coalesce_list (cl);
1131 if (dump_file && (dump_flags & TDF_DETAILS))
1133 fprintf (dump_file, "Coalesce list after sorting:\n");
1134 dump_coalesce_list (dump_file, cl);
1137 coalesce_tpa_members (tv, graph, map, cl,
1138 ((dump_flags & TDF_DETAILS) ? dump_file : NULL));
1140 type_var_delete (tv);
1141 delete_coalesce_list (cl);
1145 /* Temporary Expression Replacement (TER)
1147 Replace SSA version variables during out-of-ssa with their defining
1148 expression if there is only one use of the variable.
1150 A pass is made through the function, one block at a time. No cross block
1151 information is tracked.
1153 Variables which only have one use, and whose defining stmt is considered
1154 a replaceable expression (see check_replaceable) are entered into
1155 consideration by adding a list of dependent partitions to the version_info
1156 vector for that ssa_name_version. This information comes from the partition
1157 mapping for each USE. At the same time, the partition_dep_list vector for
1158 these partitions have this version number entered into their lists.
1160 When the use of a replaceable ssa_variable is encountered, the dependence
1161 list in version_info[] is moved to the "pending_dependence" list in case
1162 the current expression is also replaceable. (To be determined later in
1163 processing this stmt.) version_info[] for the version is then updated to
1164 point to the defining stmt and the 'replaceable' bit is set.
1166 Any partition which is defined by a statement 'kills' any expression which
1167 is dependent on this partition. Every ssa version in the partitions'
1168 dependence list is removed from future consideration.
1170 All virtual references are lumped together. Any expression which is
1171 dependent on any virtual variable (via a VUSE) has a dependence added
1172 to the special partition defined by VIRTUAL_PARTITION.
1174 Whenever a V_MAY_DEF is seen, all expressions dependent this
1175 VIRTUAL_PARTITION are removed from consideration.
1177 At the end of a basic block, all expression are removed from consideration
1178 in preparation for the next block.
1180 The end result is a vector over SSA_NAME_VERSION which is passed back to
1181 rewrite_out_of_ssa. As the SSA variables are being rewritten, instead of
1182 replacing the SSA_NAME tree element with the partition it was assigned,
1183 it is replaced with the RHS of the defining expression. */
1186 /* Dependency list element. This can contain either a partition index or a
1187 version number, depending on which list it is in. */
1189 typedef struct value_expr_d
1192 struct value_expr_d *next;
1196 /* Temporary Expression Replacement (TER) table information. */
1198 typedef struct temp_expr_table_d
1201 void **version_info;
1202 value_expr_p *partition_dep_list;
1204 bool saw_replaceable;
1205 int virtual_partition;
1206 bitmap partition_in_use;
1207 value_expr_p free_list;
1208 value_expr_p pending_dependence;
1209 } *temp_expr_table_p;
1211 /* Used to indicate a dependency on V_MAY_DEFs. */
1212 #define VIRTUAL_PARTITION(table) (table->virtual_partition)
1214 static temp_expr_table_p new_temp_expr_table (var_map);
1215 static tree *free_temp_expr_table (temp_expr_table_p);
1216 static inline value_expr_p new_value_expr (temp_expr_table_p);
1217 static inline void free_value_expr (temp_expr_table_p, value_expr_p);
1218 static inline value_expr_p find_value_in_list (value_expr_p, int,
1220 static inline void add_value_to_list (temp_expr_table_p, value_expr_p *, int);
1221 static inline void add_info_to_list (temp_expr_table_p, value_expr_p *,
1223 static value_expr_p remove_value_from_list (value_expr_p *, int);
1224 static void add_dependance (temp_expr_table_p, int, tree);
1225 static bool check_replaceable (temp_expr_table_p, tree);
1226 static void finish_expr (temp_expr_table_p, int, bool);
1227 static void mark_replaceable (temp_expr_table_p, tree);
1228 static inline void kill_expr (temp_expr_table_p, int, bool);
1229 static inline void kill_virtual_exprs (temp_expr_table_p, bool);
1230 static void find_replaceable_in_bb (temp_expr_table_p, basic_block);
1231 static tree *find_replaceable_exprs (var_map);
1232 static void dump_replaceable_exprs (FILE *, tree *);
1235 /* Create a new TER table for MAP. */
1237 static temp_expr_table_p
1238 new_temp_expr_table (var_map map)
1240 temp_expr_table_p t;
1242 t = (temp_expr_table_p) xmalloc (sizeof (struct temp_expr_table_d));
1245 t->version_info = xcalloc (num_ssa_names + 1, sizeof (void *));
1246 t->partition_dep_list = xcalloc (num_var_partitions (map) + 1,
1247 sizeof (value_expr_p));
1249 t->replaceable = BITMAP_XMALLOC ();
1250 t->partition_in_use = BITMAP_XMALLOC ();
1252 t->saw_replaceable = false;
1253 t->virtual_partition = num_var_partitions (map);
1254 t->free_list = NULL;
1255 t->pending_dependence = NULL;
1261 /* Free TER table T. If there are valid replacements, return the expression
1265 free_temp_expr_table (temp_expr_table_p t)
1270 #ifdef ENABLE_CHECKING
1272 for (x = 0; x <= num_var_partitions (t->map); x++)
1273 gcc_assert (!t->partition_dep_list[x]);
1276 while ((p = t->free_list))
1278 t->free_list = p->next;
1282 BITMAP_XFREE (t->partition_in_use);
1283 BITMAP_XFREE (t->replaceable);
1285 free (t->partition_dep_list);
1286 if (t->saw_replaceable)
1287 ret = (tree *)t->version_info;
1289 free (t->version_info);
1296 /* Allocate a new value list node. Take it from the free list in TABLE if
1299 static inline value_expr_p
1300 new_value_expr (temp_expr_table_p table)
1303 if (table->free_list)
1305 p = table->free_list;
1306 table->free_list = p->next;
1309 p = (value_expr_p) xmalloc (sizeof (struct value_expr_d));
1315 /* Add value list node P to the free list in TABLE. */
1318 free_value_expr (temp_expr_table_p table, value_expr_p p)
1320 p->next = table->free_list;
1321 table->free_list = p;
1325 /* Find VALUE if it's in LIST. Return a pointer to the list object if found,
1326 else return NULL. If LAST_PTR is provided, it will point to the previous
1327 item upon return, or NULL if this is the first item in the list. */
1329 static inline value_expr_p
1330 find_value_in_list (value_expr_p list, int value, value_expr_p *last_ptr)
1333 value_expr_p last = NULL;
1335 for (curr = list; curr; last = curr, curr = curr->next)
1337 if (curr->value == value)
1346 /* Add VALUE to LIST, if it isn't already present. TAB is the expression
1350 add_value_to_list (temp_expr_table_p tab, value_expr_p *list, int value)
1354 if (!find_value_in_list (*list, value, NULL))
1356 info = new_value_expr (tab);
1357 info->value = value;
1364 /* Add value node INFO if it's value isn't already in LIST. Free INFO if
1365 it is already in the list. TAB is the expression table. */
1368 add_info_to_list (temp_expr_table_p tab, value_expr_p *list, value_expr_p info)
1370 if (find_value_in_list (*list, info->value, NULL))
1371 free_value_expr (tab, info);
1380 /* Look for VALUE in LIST. If found, remove it from the list and return it's
1384 remove_value_from_list (value_expr_p *list, int value)
1386 value_expr_p info, last;
1388 info = find_value_in_list (*list, value, &last);
1394 last->next = info->next;
1400 /* Add a dependency between the def of ssa VERSION and VAR. If VAR is
1401 replaceable by an expression, add a dependence each of the elements of the
1402 expression. These are contained in the pending list. TAB is the
1403 expression table. */
1406 add_dependance (temp_expr_table_p tab, int version, tree var)
1411 i = SSA_NAME_VERSION (var);
1412 if (bitmap_bit_p (tab->replaceable, i))
1414 /* This variable is being substituted, so use whatever dependences
1415 were queued up when we marked this as replaceable earlier. */
1416 while ((info = tab->pending_dependence))
1418 tab->pending_dependence = info->next;
1419 /* Get the partition this variable was dependent on. Reuse this
1420 object to represent the current expression instead. */
1422 info->value = version;
1423 add_info_to_list (tab, &(tab->partition_dep_list[x]), info);
1424 add_value_to_list (tab,
1425 (value_expr_p *)&(tab->version_info[version]), x);
1426 bitmap_set_bit (tab->partition_in_use, x);
1431 i = var_to_partition (tab->map, var);
1432 gcc_assert (i != NO_PARTITION);
1433 add_value_to_list (tab, &(tab->partition_dep_list[i]), version);
1434 add_value_to_list (tab,
1435 (value_expr_p *)&(tab->version_info[version]), i);
1436 bitmap_set_bit (tab->partition_in_use, i);
1441 /* Check if expression STMT is suitable for replacement in table TAB. If so,
1442 create an expression entry. Return true if this stmt is replaceable. */
1445 check_replaceable (temp_expr_table_p tab, tree stmt)
1448 vuse_optype vuseops;
1452 int num_use_ops, version;
1453 var_map map = tab->map;
1456 if (TREE_CODE (stmt) != MODIFY_EXPR)
1459 ann = stmt_ann (stmt);
1460 defs = DEF_OPS (ann);
1462 /* Punt if there is more than 1 def, or more than 1 use. */
1463 if (NUM_DEFS (defs) != 1)
1465 def = DEF_OP (defs, 0);
1466 if (version_ref_count (map, def) != 1)
1469 /* There must be no V_MAY_DEFS. */
1470 if (NUM_V_MAY_DEFS (V_MAY_DEF_OPS (ann)) != 0)
1473 /* There must be no V_MUST_DEFS. */
1474 if (NUM_V_MUST_DEFS (V_MUST_DEF_OPS (ann)) != 0)
1477 /* Float expressions must go through memory if float-store is on. */
1478 if (flag_float_store && FLOAT_TYPE_P (TREE_TYPE (TREE_OPERAND (stmt, 1))))
1481 uses = USE_OPS (ann);
1482 num_use_ops = NUM_USES (uses);
1483 vuseops = VUSE_OPS (ann);
1485 /* Any expression which has no virtual operands and no real operands
1486 should have been propagated if it's possible to do anything with them.
1487 If this happens here, it probably exists that way for a reason, so we
1488 won't touch it. An example is:
1490 There are no virtual uses nor any real uses, so we just leave this
1491 alone to be safe. */
1493 if (num_use_ops == 0 && NUM_VUSES (vuseops) == 0)
1496 version = SSA_NAME_VERSION (def);
1498 /* Add this expression to the dependency list for each use partition. */
1499 FOR_EACH_SSA_TREE_OPERAND (var, stmt, iter, SSA_OP_USE)
1501 add_dependance (tab, version, var);
1504 /* If there are VUSES, add a dependence on virtual defs. */
1505 if (NUM_VUSES (vuseops) != 0)
1507 add_value_to_list (tab, (value_expr_p *)&(tab->version_info[version]),
1508 VIRTUAL_PARTITION (tab));
1509 add_value_to_list (tab,
1510 &(tab->partition_dep_list[VIRTUAL_PARTITION (tab)]),
1512 bitmap_set_bit (tab->partition_in_use, VIRTUAL_PARTITION (tab));
1519 /* This function will remove the expression for VERSION from replacement
1520 consideration.n table TAB If 'replace' is true, it is marked as
1521 replaceable, otherwise not. */
1524 finish_expr (temp_expr_table_p tab, int version, bool replace)
1526 value_expr_p info, tmp;
1529 /* Remove this expression from its dependent lists. The partition dependence
1530 list is retained and transfered later to whomever uses this version. */
1531 for (info = (value_expr_p) tab->version_info[version]; info; info = tmp)
1533 partition = info->value;
1534 gcc_assert (tab->partition_dep_list[partition]);
1535 tmp = remove_value_from_list (&(tab->partition_dep_list[partition]),
1538 free_value_expr (tab, tmp);
1539 /* Only clear the bit when the dependency list is emptied via
1540 a replacement. Otherwise kill_expr will take care of it. */
1541 if (!(tab->partition_dep_list[partition]) && replace)
1542 bitmap_clear_bit (tab->partition_in_use, partition);
1545 free_value_expr (tab, info);
1550 tab->saw_replaceable = true;
1551 bitmap_set_bit (tab->replaceable, version);
1555 gcc_assert (!bitmap_bit_p (tab->replaceable, version));
1556 tab->version_info[version] = NULL;
1561 /* Mark the expression associated with VAR as replaceable, and enter
1562 the defining stmt into the version_info table TAB. */
1565 mark_replaceable (temp_expr_table_p tab, tree var)
1568 int version = SSA_NAME_VERSION (var);
1569 finish_expr (tab, version, true);
1571 /* Move the dependence list to the pending list. */
1572 if (tab->version_info[version])
1574 info = (value_expr_p) tab->version_info[version];
1575 for ( ; info->next; info = info->next)
1577 info->next = tab->pending_dependence;
1578 tab->pending_dependence = (value_expr_p)tab->version_info[version];
1581 tab->version_info[version] = SSA_NAME_DEF_STMT (var);
1585 /* This function marks any expression in TAB which is dependent on PARTITION
1586 as NOT replaceable. CLEAR_BIT is used to determine whether partition_in_use
1587 should have its bit cleared. Since this routine can be called within an
1588 EXECUTE_IF_SET_IN_BITMAP, the bit can't always be cleared. */
1591 kill_expr (temp_expr_table_p tab, int partition, bool clear_bit)
1595 /* Mark every active expr dependent on this var as not replaceable. */
1596 while ((ptr = tab->partition_dep_list[partition]) != NULL)
1597 finish_expr (tab, ptr->value, false);
1600 bitmap_clear_bit (tab->partition_in_use, partition);
1604 /* This function kills all expressions in TAB which are dependent on virtual
1605 DEFs. CLEAR_BIT determines whether partition_in_use gets cleared. */
1608 kill_virtual_exprs (temp_expr_table_p tab, bool clear_bit)
1610 kill_expr (tab, VIRTUAL_PARTITION (tab), clear_bit);
1614 /* This function processes basic block BB, and looks for variables which can
1615 be replaced by their expressions. Results are stored in TAB. */
1618 find_replaceable_in_bb (temp_expr_table_p tab, basic_block bb)
1620 block_stmt_iterator bsi;
1624 var_map map = tab->map;
1628 for (bsi = bsi_start (bb); !bsi_end_p (bsi); bsi_next (&bsi))
1630 stmt = bsi_stmt (bsi);
1631 ann = stmt_ann (stmt);
1633 /* Determine if this stmt finishes an existing expression. */
1634 FOR_EACH_SSA_TREE_OPERAND (def, stmt, iter, SSA_OP_USE)
1636 if (tab->version_info[SSA_NAME_VERSION (def)])
1638 /* Mark expression as replaceable unless stmt is volatile. */
1639 if (!ann->has_volatile_ops)
1640 mark_replaceable (tab, def);
1642 finish_expr (tab, SSA_NAME_VERSION (def), false);
1646 /* Next, see if this stmt kills off an active expression. */
1647 FOR_EACH_SSA_TREE_OPERAND (def, stmt, iter, SSA_OP_DEF)
1649 partition = var_to_partition (map, def);
1650 if (partition != NO_PARTITION && tab->partition_dep_list[partition])
1651 kill_expr (tab, partition, true);
1654 /* Now see if we are creating a new expression or not. */
1655 if (!ann->has_volatile_ops)
1656 check_replaceable (tab, stmt);
1658 /* Free any unused dependency lists. */
1659 while ((p = tab->pending_dependence))
1661 tab->pending_dependence = p->next;
1662 free_value_expr (tab, p);
1665 /* A V_MAY_DEF kills any expression using a virtual operand. */
1666 if (NUM_V_MAY_DEFS (V_MAY_DEF_OPS (ann)) > 0)
1667 kill_virtual_exprs (tab, true);
1669 /* A V_MUST_DEF kills any expression using a virtual operand. */
1670 if (NUM_V_MUST_DEFS (V_MUST_DEF_OPS (ann)) > 0)
1671 kill_virtual_exprs (tab, true);
1676 /* This function is the driver routine for replacement of temporary expressions
1677 in the SSA->normal phase, operating on MAP. If there are replaceable
1678 expressions, a table is returned which maps SSA versions to the
1679 expressions they should be replaced with. A NULL_TREE indicates no
1680 replacement should take place. If there are no replacements at all,
1681 NULL is returned by the function, otherwise an expression vector indexed
1682 by SSA_NAME version numbers. */
1685 find_replaceable_exprs (var_map map)
1689 temp_expr_table_p table;
1692 table = new_temp_expr_table (map);
1697 find_replaceable_in_bb (table, bb);
1698 EXECUTE_IF_SET_IN_BITMAP ((table->partition_in_use), 0, i, bi)
1700 kill_expr (table, i, false);
1704 ret = free_temp_expr_table (table);
1709 /* Dump TER expression table EXPR to file F. */
1712 dump_replaceable_exprs (FILE *f, tree *expr)
1716 fprintf (f, "\nReplacing Expressions\n");
1717 for (x = 0; x < (int)num_ssa_names + 1; x++)
1721 var = DEF_OP (STMT_DEF_OPS (stmt), 0);
1722 print_generic_expr (f, var, TDF_SLIM);
1723 fprintf (f, " replace with --> ");
1724 print_generic_expr (f, TREE_OPERAND (stmt, 1), TDF_SLIM);
1731 /* Helper function for discover_nonconstant_array_refs.
1732 Look for ARRAY_REF nodes with non-constant indexes and mark them
1736 discover_nonconstant_array_refs_r (tree * tp, int *walk_subtrees,
1737 void *data ATTRIBUTE_UNUSED)
1741 if (IS_TYPE_OR_DECL_P (t))
1743 else if (TREE_CODE (t) == ARRAY_REF || TREE_CODE (t) == ARRAY_RANGE_REF)
1745 while (((TREE_CODE (t) == ARRAY_REF || TREE_CODE (t) == ARRAY_RANGE_REF)
1746 && is_gimple_min_invariant (TREE_OPERAND (t, 1))
1747 && (!TREE_OPERAND (t, 2)
1748 || is_gimple_min_invariant (TREE_OPERAND (t, 2))))
1749 || (TREE_CODE (t) == COMPONENT_REF
1750 && (!TREE_OPERAND (t,2)
1751 || is_gimple_min_invariant (TREE_OPERAND (t, 2))))
1752 || TREE_CODE (t) == BIT_FIELD_REF
1753 || TREE_CODE (t) == REALPART_EXPR
1754 || TREE_CODE (t) == IMAGPART_EXPR
1755 || TREE_CODE (t) == VIEW_CONVERT_EXPR
1756 || TREE_CODE (t) == NOP_EXPR
1757 || TREE_CODE (t) == CONVERT_EXPR)
1758 t = TREE_OPERAND (t, 0);
1760 if (TREE_CODE (t) == ARRAY_REF || TREE_CODE (t) == ARRAY_RANGE_REF)
1762 t = get_base_address (t);
1763 if (t && DECL_P (t))
1764 TREE_ADDRESSABLE (t) = 1;
1774 /* RTL expansion is not able to compile array references with variable
1775 offsets for arrays stored in single register. Discover such
1776 expressions and mark variables as addressable to avoid this
1780 discover_nonconstant_array_refs (void)
1783 block_stmt_iterator bsi;
1787 for (bsi = bsi_start (bb); !bsi_end_p (bsi); bsi_next (&bsi))
1788 walk_tree (bsi_stmt_ptr (bsi), discover_nonconstant_array_refs_r,
1794 /* This function will rewrite the current program using the variable mapping
1795 found in MAP. If the replacement vector VALUES is provided, any
1796 occurrences of partitions with non-null entries in the vector will be
1797 replaced with the expression in the vector instead of its mapped
1801 rewrite_trees (var_map map, tree *values)
1805 block_stmt_iterator si;
1810 #ifdef ENABLE_CHECKING
1811 /* Search for PHIs where the destination has no partition, but one
1812 or more arguments has a partition. This should not happen and can
1813 create incorrect code. */
1818 for (phi = phi_nodes (bb); phi; phi = PHI_CHAIN (phi))
1820 tree T0 = var_to_partition_to_var (map, PHI_RESULT (phi));
1822 if (T0 == NULL_TREE)
1826 for (i = 0; i < PHI_NUM_ARGS (phi); i++)
1828 tree arg = PHI_ARG_DEF (phi, i);
1830 if (TREE_CODE (arg) == SSA_NAME
1831 && var_to_partition (map, arg) != NO_PARTITION)
1833 fprintf (stderr, "Argument of PHI is in a partition :(");
1834 print_generic_expr (stderr, arg, TDF_SLIM);
1835 fprintf (stderr, "), but the result is not :");
1836 print_generic_stmt (stderr, phi, TDF_SLIM);
1837 internal_error ("SSA corruption");
1845 /* Replace PHI nodes with any required copies. */
1846 g = new_elim_graph (map->num_partitions);
1850 for (si = bsi_start (bb); !bsi_end_p (si); )
1852 size_t num_uses, num_defs;
1855 tree stmt = bsi_stmt (si);
1856 use_operand_p use_p;
1857 def_operand_p def_p;
1858 int remove = 0, is_copy = 0;
1862 get_stmt_operands (stmt);
1863 ann = stmt_ann (stmt);
1866 if (TREE_CODE (stmt) == MODIFY_EXPR
1867 && (TREE_CODE (TREE_OPERAND (stmt, 1)) == SSA_NAME))
1870 uses = USE_OPS (ann);
1871 num_uses = NUM_USES (uses);
1872 FOR_EACH_SSA_USE_OPERAND (use_p, stmt, iter, SSA_OP_USE)
1874 if (replace_use_variable (map, use_p, values))
1878 defs = DEF_OPS (ann);
1879 num_defs = NUM_DEFS (defs);
1881 /* Mark this stmt for removal if it is the list of replaceable
1883 if (values && num_defs == 1)
1885 tree def = DEF_OP (defs, 0);
1887 val = values[SSA_NAME_VERSION (def)];
1893 FOR_EACH_SSA_DEF_OPERAND (def_p, stmt, iter, SSA_OP_DEF)
1895 if (replace_def_variable (map, def_p, NULL))
1898 /* If both SSA_NAMEs coalesce to the same variable,
1899 mark the now redundant copy for removal. */
1902 && (DEF_FROM_PTR (def_p) == USE_OP (uses, 0)))
1905 if (changed & !remove)
1909 /* Remove any stmts marked for removal. */
1916 phi = phi_nodes (bb);
1920 FOR_EACH_EDGE (e, ei, bb->preds)
1921 eliminate_phi (e, g);
1925 delete_elim_graph (g);
1929 /* These are the local work structures used to determine the best place to
1930 insert the copies that were placed on edges by the SSA->normal pass.. */
1931 static varray_type edge_leader = NULL;
1932 static varray_type GTY(()) stmt_list = NULL;
1933 static bitmap leader_has_match = NULL;
1934 static edge leader_match = NULL;
1937 /* Pass this function to make_forwarder_block so that all the edges with
1938 matching PENDING_STMT lists to 'curr_stmt_list' get redirected. */
1940 same_stmt_list_p (edge e)
1942 return (e->aux == (PTR) leader_match) ? true : false;
1946 /* Return TRUE if S1 and S2 are equivalent copies. */
1948 identical_copies_p (tree s1, tree s2)
1950 #ifdef ENABLE_CHECKING
1951 gcc_assert (TREE_CODE (s1) == MODIFY_EXPR);
1952 gcc_assert (TREE_CODE (s2) == MODIFY_EXPR);
1953 gcc_assert (DECL_P (TREE_OPERAND (s1, 0)));
1954 gcc_assert (DECL_P (TREE_OPERAND (s2, 0)));
1957 if (TREE_OPERAND (s1, 0) != TREE_OPERAND (s2, 0))
1960 s1 = TREE_OPERAND (s1, 1);
1961 s2 = TREE_OPERAND (s2, 1);
1970 /* Compare the PENDING_STMT list for two edges, and return true if the lists
1971 contain the same sequence of copies. */
1974 identical_stmt_lists_p (edge e1, edge e2)
1976 tree t1 = PENDING_STMT (e1);
1977 tree t2 = PENDING_STMT (e2);
1978 tree_stmt_iterator tsi1, tsi2;
1980 gcc_assert (TREE_CODE (t1) == STATEMENT_LIST);
1981 gcc_assert (TREE_CODE (t2) == STATEMENT_LIST);
1983 for (tsi1 = tsi_start (t1), tsi2 = tsi_start (t2);
1984 !tsi_end_p (tsi1) && !tsi_end_p (tsi2);
1985 tsi_next (&tsi1), tsi_next (&tsi2))
1987 if (!identical_copies_p (tsi_stmt (tsi1), tsi_stmt (tsi2)))
1991 if (!tsi_end_p (tsi1) || ! tsi_end_p (tsi2))
1998 /* Look at all the incoming edges to block BB, and decide where the best place
1999 to insert the stmts on each edge are, and perform those insertions. Output
2000 any debug information to DEBUG_FILE. Return true if anything other than a
2001 standard edge insertion is done. */
2004 analyze_edges_for_bb (basic_block bb, FILE *debug_file)
2010 bool have_opportunity;
2011 block_stmt_iterator bsi;
2013 edge single_edge = NULL;
2018 /* Blocks which contain at least one abnormal edge cannot use
2019 make_forwarder_block. Look for these blocks, and commit any PENDING_STMTs
2020 found on edges in these block. */
2021 have_opportunity = true;
2022 FOR_EACH_EDGE (e, ei, bb->preds)
2023 if (e->flags & EDGE_ABNORMAL)
2025 have_opportunity = false;
2029 if (!have_opportunity)
2031 FOR_EACH_EDGE (e, ei, bb->preds)
2032 if (PENDING_STMT (e))
2033 bsi_commit_one_edge_insert (e, NULL);
2036 /* Find out how many edges there are with interesting pending stmts on them.
2037 Commit the stmts on edges we are not interested in. */
2038 FOR_EACH_EDGE (e, ei, bb->preds)
2040 if (PENDING_STMT (e))
2042 gcc_assert (!(e->flags & EDGE_ABNORMAL));
2043 if (e->flags & EDGE_FALLTHRU)
2045 bsi = bsi_start (e->src);
2046 if (!bsi_end_p (bsi))
2048 stmt = bsi_stmt (bsi);
2050 gcc_assert (stmt != NULL_TREE);
2051 is_label = (TREE_CODE (stmt) == LABEL_EXPR);
2052 /* Punt if it has non-label stmts, or isn't local. */
2053 if (!is_label || DECL_NONLOCAL (TREE_OPERAND (stmt, 0))
2054 || !bsi_end_p (bsi))
2056 bsi_commit_one_edge_insert (e, NULL);
2066 /* If there aren't at least 2 edges, no sharing will happen. */
2070 bsi_commit_one_edge_insert (single_edge, NULL);
2074 /* Ensure that we have empty worklists. */
2075 if (edge_leader == NULL)
2077 VARRAY_EDGE_INIT (edge_leader, 25, "edge_leader");
2078 VARRAY_TREE_INIT (stmt_list, 25, "stmt_list");
2079 leader_has_match = BITMAP_XMALLOC ();
2083 #ifdef ENABLE_CHECKING
2084 gcc_assert (VARRAY_ACTIVE_SIZE (edge_leader) == 0);
2085 gcc_assert (VARRAY_ACTIVE_SIZE (stmt_list) == 0);
2086 gcc_assert (bitmap_empty_p (leader_has_match));
2090 /* Find the "leader" block for each set of unique stmt lists. Preference is
2091 given to FALLTHRU blocks since they would need a GOTO to arrive at another
2092 block. The leader edge destination is the block which all the other edges
2093 with the same stmt list will be redirected to. */
2094 have_opportunity = false;
2095 FOR_EACH_EDGE (e, ei, bb->preds)
2097 if (PENDING_STMT (e))
2101 /* Look for the same stmt list in edge leaders list. */
2102 for (x = 0; x < VARRAY_ACTIVE_SIZE (edge_leader); x++)
2104 edge leader = VARRAY_EDGE (edge_leader, x);
2105 if (identical_stmt_lists_p (leader, e))
2107 /* Give this edge the same stmt list pointer. */
2108 PENDING_STMT (e) = NULL;
2110 bitmap_set_bit (leader_has_match, x);
2111 have_opportunity = found = true;
2116 /* If no similar stmt list, add this edge to the leader list. */
2119 VARRAY_PUSH_EDGE (edge_leader, e);
2120 VARRAY_PUSH_TREE (stmt_list, PENDING_STMT (e));
2125 /* If there are no similar lists, just issue the stmts. */
2126 if (!have_opportunity)
2128 for (x = 0; x < VARRAY_ACTIVE_SIZE (edge_leader); x++)
2129 bsi_commit_one_edge_insert (VARRAY_EDGE (edge_leader, x), NULL);
2130 VARRAY_POP_ALL (edge_leader);
2131 VARRAY_POP_ALL (stmt_list);
2132 bitmap_clear (leader_has_match);
2138 fprintf (debug_file, "\nOpportunities in BB %d for stmt/block reduction:\n",
2142 /* For each common list, create a forwarding block and issue the stmt's
2144 for (x = 0 ; x < VARRAY_ACTIVE_SIZE (edge_leader); x++)
2145 if (bitmap_bit_p (leader_has_match, x))
2147 edge new_edge, leader_edge;
2148 block_stmt_iterator bsi;
2149 tree curr_stmt_list;
2151 leader_match = leader_edge = VARRAY_EDGE (edge_leader, x);
2153 /* The tree_* cfg manipulation routines use the PENDING_EDGE field
2154 for various PHI manipulations, so it gets cleared whhen calls are
2155 made to make_forwarder_block(). So make sure the edge is clear,
2156 and use the saved stmt list. */
2157 PENDING_STMT (leader_edge) = NULL;
2158 leader_edge->aux = leader_edge;
2159 curr_stmt_list = VARRAY_TREE (stmt_list, x);
2161 new_edge = make_forwarder_block (leader_edge->dest, same_stmt_list_p,
2163 bb = new_edge->dest;
2166 fprintf (debug_file, "Splitting BB %d for Common stmt list. ",
2167 leader_edge->dest->index);
2168 fprintf (debug_file, "Original block is now BB%d.\n", bb->index);
2169 print_generic_stmt (debug_file, curr_stmt_list, TDF_VOPS);
2172 FOR_EACH_EDGE (e, ei, new_edge->src->preds)
2176 fprintf (debug_file, " Edge (%d->%d) lands here.\n",
2177 e->src->index, e->dest->index);
2180 bsi = bsi_last (leader_edge->dest);
2181 bsi_insert_after (&bsi, curr_stmt_list, BSI_NEW_STMT);
2183 leader_match = NULL;
2184 /* We should never get a new block now. */
2188 e = VARRAY_EDGE (edge_leader, x);
2189 PENDING_STMT (e) = VARRAY_TREE (stmt_list, x);
2190 bsi_commit_one_edge_insert (e, NULL);
2194 /* Clear the working data structures. */
2195 VARRAY_POP_ALL (edge_leader);
2196 VARRAY_POP_ALL (stmt_list);
2197 bitmap_clear (leader_has_match);
2203 /* This function will analyze the insertions which were performed on edges,
2204 and decide whether they should be left on that edge, or whether it is more
2205 efficient to emit some subset of them in a single block. All stmts are
2206 inserted somewhere, and if non-NULL, debug information is printed via
2210 perform_edge_inserts (FILE *dump_file)
2213 bool changed = false;
2216 fprintf(dump_file, "Analyzing Edge Insertions.\n");
2219 changed |= analyze_edges_for_bb (bb, dump_file);
2221 changed |= analyze_edges_for_bb (EXIT_BLOCK_PTR, dump_file);
2223 /* Clear out any tables which were created. */
2225 BITMAP_XFREE (leader_has_match);
2229 free_dominance_info (CDI_DOMINATORS);
2230 free_dominance_info (CDI_POST_DOMINATORS);
2233 #ifdef ENABLE_CHECKING
2239 FOR_EACH_EDGE (e, ei, bb->preds)
2241 if (PENDING_STMT (e))
2242 error (" Pending stmts not issued on PRED edge (%d, %d)\n",
2243 e->src->index, e->dest->index);
2245 FOR_EACH_EDGE (e, ei, bb->succs)
2247 if (PENDING_STMT (e))
2248 error (" Pending stmts not issued on SUCC edge (%d, %d)\n",
2249 e->src->index, e->dest->index);
2252 FOR_EACH_EDGE (e, ei, ENTRY_BLOCK_PTR->succs)
2254 if (PENDING_STMT (e))
2255 error (" Pending stmts not issued on ENTRY edge (%d, %d)\n",
2256 e->src->index, e->dest->index);
2258 FOR_EACH_EDGE (e, ei, EXIT_BLOCK_PTR->preds)
2260 if (PENDING_STMT (e))
2261 error (" Pending stmts not issued on EXIT edge (%d, %d)\n",
2262 e->src->index, e->dest->index);
2269 /* Remove the variables specified in MAP from SSA form. Any debug information
2270 is sent to DUMP. FLAGS indicate what options should be used. */
2273 remove_ssa_form (FILE *dump, var_map map, int flags)
2275 tree_live_info_p liveinfo;
2279 tree *values = NULL;
2284 /* If we are not combining temps, don't calculate live ranges for variables
2285 with only one SSA version. */
2286 if ((flags & SSANORM_COMBINE_TEMPS) == 0)
2287 compact_var_map (map, VARMAP_NO_SINGLE_DEFS);
2289 compact_var_map (map, VARMAP_NORMAL);
2291 if (dump_file && (dump_flags & TDF_DETAILS))
2292 dump_var_map (dump_file, map);
2294 liveinfo = coalesce_ssa_name (map, flags);
2296 /* Make sure even single occurrence variables are in the list now. */
2297 if ((flags & SSANORM_COMBINE_TEMPS) == 0)
2298 compact_var_map (map, VARMAP_NORMAL);
2300 if (dump_file && (dump_flags & TDF_DETAILS))
2302 fprintf (dump_file, "After Coalescing:\n");
2303 dump_var_map (dump_file, map);
2306 if (flags & SSANORM_PERFORM_TER)
2308 values = find_replaceable_exprs (map);
2309 if (values && dump_file && (dump_flags & TDF_DETAILS))
2310 dump_replaceable_exprs (dump_file, values);
2313 /* Assign real variables to the partitions now. */
2316 if (dump_file && (dump_flags & TDF_DETAILS))
2318 fprintf (dump_file, "After Root variable replacement:\n");
2319 dump_var_map (dump_file, map);
2322 if ((flags & SSANORM_COMBINE_TEMPS) && liveinfo)
2324 coalesce_vars (map, liveinfo);
2325 if (dump_file && (dump_flags & TDF_DETAILS))
2327 fprintf (dump_file, "After variable memory coalescing:\n");
2328 dump_var_map (dump_file, map);
2333 delete_tree_live_info (liveinfo);
2335 rewrite_trees (map, values);
2340 /* Remove phi nodes which have been translated back to real variables. */
2343 for (phi = phi_nodes (bb); phi; phi = next)
2345 next = PHI_CHAIN (phi);
2346 if ((flags & SSANORM_REMOVE_ALL_PHIS)
2347 || var_to_partition (map, PHI_RESULT (phi)) != NO_PARTITION)
2348 remove_phi_node (phi, NULL_TREE, bb);
2352 /* If any copies were inserted on edges, analyze and insert them now. */
2353 perform_edge_inserts (dump_file);
2358 /* Take the current function out of SSA form, as described in
2359 R. Morgan, ``Building an Optimizing Compiler'',
2360 Butterworth-Heinemann, Boston, MA, 1998. pp 176-186. */
2363 rewrite_out_of_ssa (void)
2367 int ssa_flags = (SSANORM_REMOVE_ALL_PHIS | SSANORM_USE_COALESCE_LIST);
2369 if (!flag_tree_live_range_split)
2370 ssa_flags |= SSANORM_COALESCE_PARTITIONS;
2372 eliminate_virtual_phis ();
2374 if (dump_file && (dump_flags & TDF_DETAILS))
2375 dump_tree_cfg (dump_file, dump_flags & ~TDF_DETAILS);
2377 /* We cannot allow unssa to un-gimplify trees before we instrument them. */
2378 if (flag_tree_ter && !flag_mudflap)
2379 var_flags = SSA_VAR_MAP_REF_COUNT;
2381 map = create_ssa_var_map (var_flags);
2383 if (flag_tree_combine_temps)
2384 ssa_flags |= SSANORM_COMBINE_TEMPS;
2385 if (flag_tree_ter && !flag_mudflap)
2386 ssa_flags |= SSANORM_PERFORM_TER;
2388 remove_ssa_form (dump_file, map, ssa_flags);
2390 if (dump_file && (dump_flags & TDF_DETAILS))
2391 dump_tree_cfg (dump_file, dump_flags & ~TDF_DETAILS);
2393 /* Do some cleanups which reduce the amount of data the
2394 tree->rtl expanders deal with. */
2395 cfg_remove_useless_stmts ();
2397 /* Flush out flow graph and SSA data. */
2398 delete_var_map (map);
2400 /* Mark arrays indexed with non-constant indices with TREE_ADDRESSABLE. */
2401 discover_nonconstant_array_refs ();
2405 /* Define the parameters of the out of SSA pass. */
2407 struct tree_opt_pass pass_del_ssa =
2409 "optimized", /* name */
2411 rewrite_out_of_ssa, /* execute */
2414 0, /* static_pass_number */
2415 TV_TREE_SSA_TO_NORMAL, /* tv_id */
2416 PROP_cfg | PROP_ssa | PROP_alias, /* properties_required */
2417 0, /* properties_provided */
2418 /* ??? If TER is enabled, we also kill gimple. */
2419 PROP_ssa, /* properties_destroyed */
2420 TODO_verify_ssa | TODO_verify_flow
2421 | TODO_verify_stmts, /* todo_flags_start */
2422 TODO_dump_func | TODO_ggc_collect, /* todo_flags_finish */