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Diffstat (limited to 'gcc/tree-outof-ssa.c')
| -rw-r--r-- | gcc/tree-outof-ssa.c | 2223 |
1 files changed, 2223 insertions, 0 deletions
diff --git a/gcc/tree-outof-ssa.c b/gcc/tree-outof-ssa.c new file mode 100644 index 00000000000..d1899981c1f --- /dev/null +++ b/gcc/tree-outof-ssa.c @@ -0,0 +1,2223 @@ +/* Convert a program in SSA form into Normal form. + Copyright (C) 2004 Free Software Foundation, Inc. + Contributed by Andrew Macleod <amacleod@redhat.com> + +This file is part of GCC. + +GCC is free software; you can redistribute it and/or modify +it under the terms of the GNU General Public License as published by +the Free Software Foundation; either version 2, or (at your option) +any later version. + +GCC is distributed in the hope that it will be useful, +but WITHOUT ANY WARRANTY; without even the implied warranty of +MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the +GNU General Public License for more details. + +You should have received a copy of the GNU General Public License +along with GCC; see the file COPYING. If not, write to +the Free Software Foundation, 59 Temple Place - Suite 330, +Boston, MA 02111-1307, USA. */ + +#include "config.h" +#include "system.h" +#include "coretypes.h" +#include "tm.h" +#include "tree.h" +#include "flags.h" +#include "rtl.h" +#include "tm_p.h" +#include "ggc.h" +#include "langhooks.h" +#include "hard-reg-set.h" +#include "basic-block.h" +#include "output.h" +#include "errors.h" +#include "expr.h" +#include "function.h" +#include "diagnostic.h" +#include "bitmap.h" +#include "tree-flow.h" +#include "tree-gimple.h" +#include "tree-inline.h" +#include "varray.h" +#include "timevar.h" +#include "tree-alias-common.h" +#include "hashtab.h" +#include "tree-dump.h" +#include "tree-ssa-live.h" +#include "tree-pass.h" + +/* Used to hold all the components required to do SSA PHI elimination. + The node and pred/succ list is a simple linear list of nodes and + edges represented as pairs of nodes. + + The predecessor and successor list: Nodes are entered in pairs, where + [0] ->PRED, [1]->SUCC. All the even indexes in the array represent + predecessors, all the odd elements are successors. + + Rationale: + When implemented as bitmaps, very large programs SSA->Normal times were + being dominated by clearing the interference graph. + + Typically this list of edges is extremely small since it only includes + PHI results and uses from a single edge which have not coalesced with + each other. This means that no virtual PHI nodes are included, and + empirical evidence suggests that the number of edges rarely exceed + 3, and in a bootstrap of GCC, the maximum size encountered was 7. + This also limits the number of possible nodes that are involved to + rarely more than 6, and in the bootstrap of gcc, the maximum number + of nodes encountered was 12. */ + +typedef struct _elim_graph { + /* Size of the elimination vectors. */ + int size; + + /* List of nodes in the elimination graph. */ + varray_type nodes; + + /* The predecessor and successor edge list. */ + varray_type edge_list; + + /* Visited vector. */ + sbitmap visited; + + /* Stack for visited nodes. */ + varray_type stack; + + /* The variable partition map. */ + var_map map; + + /* Edge being eliminated by this graph. */ + edge e; + + /* List of constant copies to emit. These are pushed on in pairs. */ + varray_type const_copies; +} *elim_graph; + + +/* Local functions. */ +static tree create_temp (tree); +static void insert_copy_on_edge (edge, tree, tree); +static elim_graph new_elim_graph (int); +static inline void delete_elim_graph (elim_graph); +static inline void clear_elim_graph (elim_graph); +static inline int elim_graph_size (elim_graph); +static inline void elim_graph_add_node (elim_graph, tree); +static inline void elim_graph_add_edge (elim_graph, int, int); +static inline int elim_graph_remove_succ_edge (elim_graph, int); + +static inline void eliminate_name (elim_graph, tree); +static void eliminate_build (elim_graph, basic_block, int); +static void elim_forward (elim_graph, int); +static int elim_unvisited_predecessor (elim_graph, int); +static void elim_backward (elim_graph, int); +static void elim_create (elim_graph, int); +static void eliminate_phi (edge, int, elim_graph); +static tree_live_info_p coalesce_ssa_name (var_map, int); +static void assign_vars (var_map); +static bool replace_use_variable (var_map, use_operand_p, tree *); +static bool replace_def_variable (var_map, def_operand_p, tree *); +static void eliminate_virtual_phis (void); +static void coalesce_abnormal_edges (var_map, conflict_graph, root_var_p); +static void print_exprs (FILE *, const char *, tree, const char *, tree, + const char *); +static void print_exprs_edge (FILE *, edge, const char *, tree, const char *, + tree); + + +/* Create a temporary variable based on the type of variable T. Use T's name + as the prefix. */ + +static tree +create_temp (tree t) +{ + tree tmp; + const char *name = NULL; + tree type; + + if (TREE_CODE (t) == SSA_NAME) + t = SSA_NAME_VAR (t); + + if (TREE_CODE (t) != VAR_DECL + && TREE_CODE (t) != PARM_DECL) + abort (); + + type = TREE_TYPE (t); + tmp = DECL_NAME (t); + if (tmp) + name = IDENTIFIER_POINTER (tmp); + + if (name == NULL) + name = "temp"; + tmp = create_tmp_var (type, name); + DECL_ARTIFICIAL (tmp) = DECL_ARTIFICIAL (t); + add_referenced_tmp_var (tmp); + + /* add_referenced_tmp_var will create the annotation and set up some + of the flags in the annotation. However, some flags we need to + inherit from our original variable. */ + var_ann (tmp)->type_mem_tag = var_ann (t)->type_mem_tag; + if (is_call_clobbered (t)) + mark_call_clobbered (tmp); + + return tmp; +} + + +/* This helper function fill insert a copy from a constant or variable SRC to + variable DEST on edge E. */ + +static void +insert_copy_on_edge (edge e, tree dest, tree src) +{ + tree copy; + + copy = build (MODIFY_EXPR, TREE_TYPE (dest), dest, src); + set_is_used (dest); + + if (TREE_CODE (src) == ADDR_EXPR) + src = TREE_OPERAND (src, 0); + if (TREE_CODE (src) == VAR_DECL || TREE_CODE (src) == PARM_DECL) + set_is_used (src); + + if (dump_file && (dump_flags & TDF_DETAILS)) + { + fprintf (dump_file, + "Inserting a copy on edge BB%d->BB%d :", + e->src->index, + e->dest->index); + print_generic_expr (dump_file, copy, dump_flags); + fprintf (dump_file, "\n"); + } + + bsi_insert_on_edge (e, copy); +} + + +/* Create an elimination graph with SIZE nodes and associated data + structures. */ + +static elim_graph +new_elim_graph (int size) +{ + elim_graph g = (elim_graph) xmalloc (sizeof (struct _elim_graph)); + + VARRAY_TREE_INIT (g->nodes, 30, "Elimination Node List"); + VARRAY_TREE_INIT (g->const_copies, 20, "Elimination Constant Copies"); + VARRAY_INT_INIT (g->edge_list, 20, "Elimination Edge List"); + VARRAY_INT_INIT (g->stack, 30, " Elimination Stack"); + + g->visited = sbitmap_alloc (size); + + return g; +} + + +/* Empty elimination graph G. */ + +static inline void +clear_elim_graph (elim_graph g) +{ + VARRAY_POP_ALL (g->nodes); + VARRAY_POP_ALL (g->edge_list); +} + + +/* Delete elimination graph G. */ + +static inline void +delete_elim_graph (elim_graph g) +{ + sbitmap_free (g->visited); + free (g); +} + + +/* Return the number of nodes in graph G. */ + +static inline int +elim_graph_size (elim_graph g) +{ + return VARRAY_ACTIVE_SIZE (g->nodes); +} + + +/* Add NODE to graph G, if it doesn't exist already. */ + +static inline void +elim_graph_add_node (elim_graph g, tree node) +{ + int x; + for (x = 0; x < elim_graph_size (g); x++) + if (VARRAY_TREE (g->nodes, x) == node) + return; + VARRAY_PUSH_TREE (g->nodes, node); +} + + +/* Add the edge PRED->SUCC to graph G. */ + +static inline void +elim_graph_add_edge (elim_graph g, int pred, int succ) +{ + VARRAY_PUSH_INT (g->edge_list, pred); + VARRAY_PUSH_INT (g->edge_list, succ); +} + + +/* Remove an edge from graph G for which NODE is the predecessor, and + return the successor node. -1 is returned if there is no such edge. */ + +static inline int +elim_graph_remove_succ_edge (elim_graph g, int node) +{ + int y; + unsigned x; + for (x = 0; x < VARRAY_ACTIVE_SIZE (g->edge_list); x += 2) + if (VARRAY_INT (g->edge_list, x) == node) + { + VARRAY_INT (g->edge_list, x) = -1; + y = VARRAY_INT (g->edge_list, x + 1); + VARRAY_INT (g->edge_list, x + 1) = -1; + return y; + } + return -1; +} + + +/* Find all the nodes in GRAPH which are successors to NODE in the + edge list. VAR will hold the partition number found. CODE is the + code fragment executed for every node found. */ + +#define FOR_EACH_ELIM_GRAPH_SUCC(GRAPH, NODE, VAR, CODE) \ +do { \ + unsigned x_; \ + int y_; \ + for (x_ = 0; x_ < VARRAY_ACTIVE_SIZE ((GRAPH)->edge_list); x_ += 2) \ + { \ + y_ = VARRAY_INT ((GRAPH)->edge_list, x_); \ + if (y_ != (NODE)) \ + continue; \ + (VAR) = VARRAY_INT ((GRAPH)->edge_list, x_ + 1); \ + CODE; \ + } \ +} while (0) + + +/* Find all the nodes which are predecessors of NODE in the edge list for + GRAPH. VAR will hold the partition number found. CODE is the + code fragment executed for every node found. */ + +#define FOR_EACH_ELIM_GRAPH_PRED(GRAPH, NODE, VAR, CODE) \ +do { \ + unsigned x_; \ + int y_; \ + for (x_ = 0; x_ < VARRAY_ACTIVE_SIZE ((GRAPH)->edge_list); x_ += 2) \ + { \ + y_ = VARRAY_INT ((GRAPH)->edge_list, x_ + 1); \ + if (y_ != (NODE)) \ + continue; \ + (VAR) = VARRAY_INT ((GRAPH)->edge_list, x_); \ + CODE; \ + } \ +} while (0) + + +/* Add T to elimination graph G. */ + +static inline void +eliminate_name (elim_graph g, tree T) +{ + elim_graph_add_node (g, T); +} + + +/* Build elimination graph G for basic block BB on incoming PHI edge I. */ + +static void +eliminate_build (elim_graph g, basic_block B, int i) +{ + tree phi; + tree T0, Ti; + int p0, pi; + + clear_elim_graph (g); + + for (phi = phi_nodes (B); phi; phi = PHI_CHAIN (phi)) + { + T0 = var_to_partition_to_var (g->map, PHI_RESULT (phi)); + + /* Ignore results which are not in partitions. */ + if (T0 == NULL_TREE) + continue; + + if (PHI_ARG_EDGE (phi, i) == g->e) + Ti = PHI_ARG_DEF (phi, i); + else + { + /* On rare occasions, a PHI node may not have the arguments + in the same order as all of the other PHI nodes. If they don't + match, find the appropriate index here. */ + pi = phi_arg_from_edge (phi, g->e); + if (pi == -1) + abort(); + Ti = PHI_ARG_DEF (phi, pi); + } + + /* If this argument is a constant, or a SSA_NAME which is being + left in SSA form, just queue a copy to be emitted on this + edge. */ + if (!phi_ssa_name_p (Ti) + || (TREE_CODE (Ti) == SSA_NAME + && var_to_partition (g->map, Ti) == NO_PARTITION)) + { + /* Save constant copies until all other copies have been emitted + on this edge. */ + VARRAY_PUSH_TREE (g->const_copies, T0); + VARRAY_PUSH_TREE (g->const_copies, Ti); + } + else + { + Ti = var_to_partition_to_var (g->map, Ti); + if (T0 != Ti) + { + eliminate_name (g, T0); + eliminate_name (g, Ti); + p0 = var_to_partition (g->map, T0); + pi = var_to_partition (g->map, Ti); + elim_graph_add_edge (g, p0, pi); + } + } + } +} + + +/* Push successors of T onto the elimination stack for G. */ + +static void +elim_forward (elim_graph g, int T) +{ + int S; + SET_BIT (g->visited, T); + FOR_EACH_ELIM_GRAPH_SUCC (g, T, S, + { + if (!TEST_BIT (g->visited, S)) + elim_forward (g, S); + }); + VARRAY_PUSH_INT (g->stack, T); +} + + +/* Return 1 if there unvisited predecessors of T in graph G. */ + +static int +elim_unvisited_predecessor (elim_graph g, int T) +{ + int P; + FOR_EACH_ELIM_GRAPH_PRED (g, T, P, + { + if (!TEST_BIT (g->visited, P)) + return 1; + }); + return 0; +} + +/* Process predecessors first, and insert a copy. */ + +static void +elim_backward (elim_graph g, int T) +{ + int P; + SET_BIT (g->visited, T); + FOR_EACH_ELIM_GRAPH_PRED (g, T, P, + { + if (!TEST_BIT (g->visited, P)) + { + elim_backward (g, P); + insert_copy_on_edge (g->e, + partition_to_var (g->map, P), + partition_to_var (g->map, T)); + } + }); +} + +/* Insert required copies for T in graph G. Check for a strongly connected + region, and create a temporary to break the cycle if one is found. */ + +static void +elim_create (elim_graph g, int T) +{ + tree U; + int P, S; + + if (elim_unvisited_predecessor (g, T)) + { + U = create_temp (partition_to_var (g->map, T)); + insert_copy_on_edge (g->e, U, partition_to_var (g->map, T)); + FOR_EACH_ELIM_GRAPH_PRED (g, T, P, + { + if (!TEST_BIT (g->visited, P)) + { + elim_backward (g, P); + insert_copy_on_edge (g->e, partition_to_var (g->map, P), U); + } + }); + } + else + { + S = elim_graph_remove_succ_edge (g, T); + if (S != -1) + { + SET_BIT (g->visited, T); + insert_copy_on_edge (g->e, + partition_to_var (g->map, T), + partition_to_var (g->map, S)); + } + } + +} + +/* Eliminate all the phi nodes on edge E in graph G. I is the usual PHI + index that edge E's values are found on. */ + +static void +eliminate_phi (edge e, int i, elim_graph g) +{ + int num_nodes = 0; + int x; + basic_block B = e->dest; + +#if defined ENABLE_CHECKING + if (i == -1) + abort (); + if (VARRAY_ACTIVE_SIZE (g->const_copies) != 0) + abort (); +#endif + + /* Abnormal edges already have everything coalesced, or the coalescer + would have aborted. */ + if (e->flags & EDGE_ABNORMAL) + return; + + num_nodes = num_var_partitions (g->map); + g->e = e; + + eliminate_build (g, B, i); + + if (elim_graph_size (g) != 0) + { + sbitmap_zero (g->visited); + VARRAY_POP_ALL (g->stack); + + for (x = 0; x < elim_graph_size (g); x++) + { + tree var = VARRAY_TREE (g->nodes, x); + int p = var_to_partition (g->map, var); + if (!TEST_BIT (g->visited, p)) + elim_forward (g, p); + } + + sbitmap_zero (g->visited); + while (VARRAY_ACTIVE_SIZE (g->stack) > 0) + { + x = VARRAY_TOP_INT (g->stack); + VARRAY_POP (g->stack); + if (!TEST_BIT (g->visited, x)) + elim_create (g, x); + } + } + + /* If there are any pending constant copies, issue them now. */ + while (VARRAY_ACTIVE_SIZE (g->const_copies) > 0) + { + tree src, dest; + src = VARRAY_TOP_TREE (g->const_copies); + VARRAY_POP (g->const_copies); + dest = VARRAY_TOP_TREE (g->const_copies); + VARRAY_POP (g->const_copies); + insert_copy_on_edge (e, dest, src); + } +} + + +/* Shortcut routine to print messages to file F of the form: + "STR1 EXPR1 STR2 EXPR2 STR3." */ + +static void +print_exprs (FILE *f, const char *str1, tree expr1, const char *str2, + tree expr2, const char *str3) +{ + fprintf (f, "%s", str1); + print_generic_expr (f, expr1, TDF_SLIM); + fprintf (f, "%s", str2); + print_generic_expr (f, expr2, TDF_SLIM); + fprintf (f, "%s", str3); +} + + +/* Shortcut routine to print abnormal edge messages to file F of the form: + "STR1 EXPR1 STR2 EXPR2 across edge E. */ + +static void +print_exprs_edge (FILE *f, edge e, const char *str1, tree expr1, + const char *str2, tree expr2) +{ + print_exprs (f, str1, expr1, str2, expr2, " across an abnormal edge"); + fprintf (f, " from BB%d->BB%d\n", e->src->index, + e->dest->index); +} + + +/* Coalesce partitions in MAP which are live across abnormal edges in GRAPH. + RV is the root variable groupings of the partitions in MAP. Since code + cannot be inserted on these edges, failure to coalesce something across + an abnormal edge is an error. */ + +static void +coalesce_abnormal_edges (var_map map, conflict_graph graph, root_var_p rv) +{ + basic_block bb; + edge e; + tree phi, var, tmp; + int x, y; + + /* Code cannot be inserted on abnormal edges. Look for all abnormal + edges, and coalesce any PHI results with their arguments across + that edge. */ + + FOR_EACH_BB (bb) + for (e = bb->succ; e; e = e->succ_next) + if (e->dest != EXIT_BLOCK_PTR && e->flags & EDGE_ABNORMAL) + for (phi = phi_nodes (e->dest); phi; phi = PHI_CHAIN (phi)) + { + /* Visit each PHI on the destination side of this abnormal + edge, and attempt to coalesce the argument with the result. */ + var = PHI_RESULT (phi); + x = var_to_partition (map, var); + + /* Ignore results which are not relevant. */ + if (x == NO_PARTITION) + continue; + + y = phi_arg_from_edge (phi, e); + if (y == -1) + abort (); + + tmp = PHI_ARG_DEF (phi, y); + if (!phi_ssa_name_p (tmp)) + { + print_exprs_edge (stderr, e, + "\nConstant argument in PHI. Can't insert :", + var, " = ", tmp); + abort (); + } + y = var_to_partition (map, tmp); + if (x == NO_PARTITION || y == NO_PARTITION) + abort (); + if (root_var_find (rv, x) != root_var_find (rv, y)) + { + print_exprs_edge (stderr, e, "\nDifferent root vars: ", + root_var (rv, root_var_find (rv, x)), + " and ", + root_var (rv, root_var_find (rv, y))); + abort (); + } + + if (x != y) + { + if (!conflict_graph_conflict_p (graph, x, y)) + { + /* Now map the partitions back to their real variables. */ + var = partition_to_var (map, x); + tmp = partition_to_var (map, y); + if (dump_file + && (dump_flags & TDF_DETAILS)) + { + print_exprs_edge (dump_file, e, + "ABNORMAL: Coalescing ", + var, " and ", tmp); + } + if (var_union (map, var, tmp) == NO_PARTITION) + { + print_exprs_edge (stderr, e, "\nUnable to coalesce", + partition_to_var (map, x), " and ", + partition_to_var (map, y)); + abort (); + } + conflict_graph_merge_regs (graph, x, y); + } + else + { + print_exprs_edge (stderr, e, "\n Conflict ", + partition_to_var (map, x), + " and ", partition_to_var (map, y)); + abort (); + } + } + } +} + + +/* Reduce the number of live ranges in MAP. Live range information is + returned if FLAGS indicates that we are combining temporaries, otherwise + NULL is returned. The only partitions which are associated with actual + variables at this point are those which are forced to be coalesced for + various reason. (live on entry, live across abnormal edges, etc.). */ + +static tree_live_info_p +coalesce_ssa_name (var_map map, int flags) +{ + int num, x, i; + sbitmap live; + tree var, phi; + root_var_p rv; + tree_live_info_p liveinfo; + var_ann_t ann; + conflict_graph graph; + basic_block bb; + coalesce_list_p cl = NULL; + + if (num_var_partitions (map) <= 1) + return NULL; + + /* If no preference given, use cheap coalescing of all partitions. */ + if ((flags & (SSANORM_COALESCE_PARTITIONS | SSANORM_USE_COALESCE_LIST)) == 0) + flags |= SSANORM_COALESCE_PARTITIONS; + + liveinfo = calculate_live_on_entry (map); + calculate_live_on_exit (liveinfo); + rv = root_var_init (map); + + /* Remove single element variable from the list. */ + root_var_compact (rv); + + if (flags & SSANORM_USE_COALESCE_LIST) + { + cl = create_coalesce_list (map); + + /* Add all potential copies via PHI arguments to the list. */ + FOR_EACH_BB (bb) + { + for (phi = phi_nodes (bb); phi; phi = PHI_CHAIN (phi)) + { + tree res = PHI_RESULT (phi); + int p = var_to_partition (map, res); + if (p == NO_PARTITION) + continue; + for (x = 0; x < PHI_NUM_ARGS (phi); x++) + { + tree arg = PHI_ARG_DEF (phi, x); + int p2; + + if (TREE_CODE (arg) != SSA_NAME) + continue; + if (SSA_NAME_VAR (res) != SSA_NAME_VAR (arg)) + continue; + p2 = var_to_partition (map, PHI_ARG_DEF (phi, x)); + if (p2 != NO_PARTITION) + add_coalesce (cl, p, p2, 1); + } + } + } + + /* Coalesce all the result decls together. */ + var = NULL_TREE; + i = 0; + for (x = 0; x < num_var_partitions (map); x++) + { + tree p = partition_to_var (map, x); + if (TREE_CODE (SSA_NAME_VAR(p)) == RESULT_DECL) + { + if (var == NULL_TREE) + { + var = p; + i = x; + } + else + add_coalesce (cl, i, x, 1); + } + } + } + + /* Build a conflict graph. */ + graph = build_tree_conflict_graph (liveinfo, rv, cl); + + if (cl) + { + if (dump_file && (dump_flags & TDF_DETAILS)) + { + fprintf (dump_file, "Before sorting:\n"); + dump_coalesce_list (dump_file, cl); + } + + sort_coalesce_list (cl); + + if (dump_file && (dump_flags & TDF_DETAILS)) + { + fprintf (dump_file, "\nAfter sorting:\n"); + dump_coalesce_list (dump_file, cl); + } + } + + /* Put the single element variables back in. */ + root_var_decompact (rv); + + /* First, coalesce all live on entry variables to their root variable. + This will ensure the first use is coming from the correct location. */ + + live = sbitmap_alloc (num_var_partitions (map)); + sbitmap_zero (live); + + /* Set 'live' vector to indicate live on entry partitions. */ + num = num_var_partitions (map); + for (x = 0 ; x < num; x++) + { + var = partition_to_var (map, x); + if (default_def (SSA_NAME_VAR (var)) == var) + SET_BIT (live, x); + } + + if ((flags & SSANORM_COMBINE_TEMPS) == 0) + { + delete_tree_live_info (liveinfo); + liveinfo = NULL; + } + + /* Assign root variable as partition representative for each live on entry + partition. */ + EXECUTE_IF_SET_IN_SBITMAP (live, 0, x, + { + var = root_var (rv, root_var_find (rv, x)); + ann = var_ann (var); + /* If these aren't already coalesced... */ + if (partition_to_var (map, x) != var) + { + if (ann->out_of_ssa_tag) + { + /* This root variable has already been assigned to another + partition which is not coalesced with this one. */ + abort (); + } + + if (dump_file && (dump_flags & TDF_DETAILS)) + { + print_exprs (dump_file, "Must coalesce ", + partition_to_var (map, x), + " with the root variable ", var, ".\n"); + } + + change_partition_var (map, var, x); + } + }); + + sbitmap_free (live); + + /* Coalesce partitions live across abnormal edges. */ + coalesce_abnormal_edges (map, graph, rv); + + if (dump_file && (dump_flags & TDF_DETAILS)) + dump_var_map (dump_file, map); + + /* Coalesce partitions. */ + if (flags & SSANORM_USE_COALESCE_LIST) + coalesce_tpa_members (rv, graph, map, cl, + ((dump_flags & TDF_DETAILS) ? dump_file + : NULL)); + + + if (flags & SSANORM_COALESCE_PARTITIONS) + coalesce_tpa_members (rv, graph, map, NULL, + ((dump_flags & TDF_DETAILS) ? dump_file + : NULL)); + if (cl) + delete_coalesce_list (cl); + root_var_delete (rv); + conflict_graph_delete (graph); + + return liveinfo; +} + + +/* Take the ssa-name var_map MAP, and assign real variables to each + partition. */ + +static void +assign_vars (var_map map) +{ + int x, i, num, rep; + tree t, var; + var_ann_t ann; + root_var_p rv; + + rv = root_var_init (map); + if (!rv) + return; + + /* Coalescing may already have forced some partitions to their root + variable. Find these and tag them. */ + + num = num_var_partitions (map); + for (x = 0; x < num; x++) + { + var = partition_to_var (map, x); + if (TREE_CODE (var) != SSA_NAME) + { + /* Coalescing will already have verified that more than one + partition doesn't have the same root variable. Simply marked + the variable as assigned. */ + ann = var_ann (var); + ann->out_of_ssa_tag = 1; + if (dump_file && (dump_flags & TDF_DETAILS)) + { + fprintf (dump_file, "partition %d has variable ", x); + print_generic_expr (dump_file, var, TDF_SLIM); + fprintf (dump_file, " assigned to it.\n"); + } + + } + } + + num = root_var_num (rv); + for (x = 0; x < num; x++) + { + var = root_var (rv, x); + ann = var_ann (var); + for (i = root_var_first_partition (rv, x); + i != ROOT_VAR_NONE; + i = root_var_next_partition (rv, i)) + { + t = partition_to_var (map, i); + + if (t == var || TREE_CODE (t) != SSA_NAME) + continue; + + rep = var_to_partition (map, t); + + if (!ann->out_of_ssa_tag) + { + if (dump_file && (dump_flags & TDF_DETAILS)) + print_exprs (dump_file, "", t, " --> ", var, "\n"); + change_partition_var (map, var, rep); + continue; + } + + if (dump_file && (dump_flags & TDF_DETAILS)) + print_exprs (dump_file, "", t, " not coalesced with ", var, + ""); + + var = create_temp (t); + change_partition_var (map, var, rep); + ann = var_ann (var); + + if (dump_file && (dump_flags & TDF_DETAILS)) + { + fprintf (dump_file, " --> New temp: '"); + print_generic_expr (dump_file, var, TDF_SLIM); + fprintf (dump_file, "'\n"); + } + } + } + + root_var_delete (rv); +} + + +/* Replace use operand P with whatever variable it has been rewritten to based + on the partitions in MAP. EXPR is an optional expression vector over SSA + versions which is used to replace P with an expression instead of a variable. + If the stmt is changed, return true. */ + +static inline bool +replace_use_variable (var_map map, use_operand_p p, tree *expr) +{ + tree new_var; + tree var = USE_FROM_PTR (p); + + /* Check if we are replacing this variable with an expression. */ + if (expr) + { + int version = SSA_NAME_VERSION (var); + if (expr[version]) + { + tree new_expr = TREE_OPERAND (expr[version], 1); + SET_USE (p, new_expr); + /* Clear the stmt's RHS, or GC might bite us. */ + TREE_OPERAND (expr[version], 1) = NULL_TREE; + return true; + } + } + + new_var = var_to_partition_to_var (map, var); + if (new_var) + { + SET_USE (p, new_var); + set_is_used (new_var); + return true; + } + return false; +} + + +/* Replace def operand DEF_P with whatever variable it has been rewritten to + based on the partitions in MAP. EXPR is an optional expression vector over + SSA versions which is used to replace DEF_P with an expression instead of a + variable. If the stmt is changed, return true. */ + +static inline bool +replace_def_variable (var_map map, def_operand_p def_p, tree *expr) +{ + tree new_var; + tree var = DEF_FROM_PTR (def_p); + + /* Check if we are replacing this variable with an expression. */ + if (expr) + { + int version = SSA_NAME_VERSION (var); + if (expr[version]) + { + tree new_expr = TREE_OPERAND (expr[version], 1); + SET_DEF (def_p, new_expr); + /* Clear the stmt's RHS, or GC might bite us. */ + TREE_OPERAND (expr[version], 1) = NULL_TREE; + return true; + } + } + + new_var = var_to_partition_to_var (map, var); + if (new_var) + { + SET_DEF (def_p, new_var); + set_is_used (new_var); + return true; + } + return false; +} + + +/* Remove any PHI node which is a virtual PHI. */ + +static void +eliminate_virtual_phis (void) +{ + basic_block bb; + tree phi, next; + + FOR_EACH_BB (bb) + { + for (phi = phi_nodes (bb); phi; phi = next) + { + next = PHI_CHAIN (phi); + if (!is_gimple_reg (SSA_NAME_VAR (PHI_RESULT (phi)))) + { +#ifdef ENABLE_CHECKING + int i; + /* There should be no arguments of this PHI which are in + the partition list, or we get incorrect results. */ + for (i = 0; i < PHI_NUM_ARGS (phi); i++) + { + tree arg = PHI_ARG_DEF (phi, i); + if (TREE_CODE (arg) == SSA_NAME + && is_gimple_reg (SSA_NAME_VAR (arg))) + { + fprintf (stderr, "Argument of PHI is not virtual ("); + print_generic_expr (stderr, arg, TDF_SLIM); + fprintf (stderr, "), but the result is :"); + print_generic_stmt (stderr, phi, TDF_SLIM); + abort(); + } + } +#endif + remove_phi_node (phi, NULL_TREE, bb); + } + } + } +} + + +/* This routine will coalesce variables in MAP of the same type which do not + interfere with each other. LIVEINFO is the live range info for variables + of interest. This will both reduce the memory footprint of the stack, and + allow us to coalesce together local copies of globals and scalarized + component refs. */ + +static void +coalesce_vars (var_map map, tree_live_info_p liveinfo) +{ + basic_block bb; + type_var_p tv; + tree var; + int x, p, p2; + coalesce_list_p cl; + conflict_graph graph; + + cl = create_coalesce_list (map); + + /* Merge all the live on entry vectors for coalesced partitions. */ + for (x = 0; x < num_var_partitions (map); x++) + { + var = partition_to_var (map, x); + p = var_to_partition (map, var); + if (p != x) + live_merge_and_clear (liveinfo, p, x); + } + + /* When PHI nodes are turned into copies, the result of each PHI node + becomes live on entry to the block. Mark these now. */ + FOR_EACH_BB (bb) + { + tree phi, arg; + int p; + for (phi = phi_nodes (bb); phi; phi = PHI_CHAIN (phi)) + { + p = var_to_partition (map, PHI_RESULT (phi)); + + /* Skip virtual PHI nodes. */ + if (p == NO_PARTITION) + continue; + + make_live_on_entry (liveinfo, bb, p); + + /* Each argument is a potential copy operation. Add any arguments + which are not coalesced to the result to the coalesce list. */ + for (x = 0; x < PHI_NUM_ARGS (phi); x++) + { + arg = PHI_ARG_DEF (phi, x); + if (!phi_ssa_name_p (arg)) + continue; + p2 = var_to_partition (map, arg); + if (p2 == NO_PARTITION) + continue; + if (p != p2) + add_coalesce (cl, p, p2, 1); + } + } + } + + + /* Re-calculate live on exit info. */ + calculate_live_on_exit (liveinfo); + + if (dump_file && (dump_flags & TDF_DETAILS)) + { + fprintf (dump_file, "Live range info for variable memory coalescing.\n"); + dump_live_info (dump_file, liveinfo, LIVEDUMP_ALL); + + fprintf (dump_file, "Coalesce list from phi nodes:\n"); + dump_coalesce_list (dump_file, cl); + } + + + tv = type_var_init (map); + if (dump_file) + type_var_dump (dump_file, tv); + type_var_compact (tv); + if (dump_file) + type_var_dump (dump_file, tv); + + graph = build_tree_conflict_graph (liveinfo, tv, cl); + + type_var_decompact (tv); + if (dump_file && (dump_flags & TDF_DETAILS)) + { + fprintf (dump_file, "type var list now looks like:n"); + type_var_dump (dump_file, tv); + + fprintf (dump_file, "Coalesce list after conflict graph build:\n"); + dump_coalesce_list (dump_file, cl); + } + + sort_coalesce_list (cl); + if (dump_file && (dump_flags & TDF_DETAILS)) + { + fprintf (dump_file, "Coalesce list after sorting:\n"); + dump_coalesce_list (dump_file, cl); + } + + coalesce_tpa_members (tv, graph, map, cl, + ((dump_flags & TDF_DETAILS) ? dump_file : NULL)); + + type_var_delete (tv); + delete_coalesce_list (cl); +} + + +/* Temporary Expression Replacement (TER) + + Replace SSA version variables during out-of-ssa with their defining + expression if there is only one use of the variable. + + A pass is made through the function, one block at a time. No cross block + information is tracked. + + Variables which only have one use, and whose defining stmt is considered + a replaceable expression (see check_replaceable) are entered into + consideration by adding a list of dependent partitions to the version_info + vector for that ssa_name_version. This information comes from the partition + mapping for each USE. At the same time, the partition_dep_list vector for + these partitions have this version number entered into their lists. + + When the use of a replaceable ssa_variable is encountered, the dependence + list in version_info[] is moved to the "pending_dependence" list in case + the current expression is also replaceable. (To be determined later in + processing this stmt.) version_info[] for the version is then updated to + point to the defining stmt and the 'replaceable' bit is set. + + Any partition which is defined by a statement 'kills' any expression which + is dependent on this partition. Every ssa version in the partitions' + dependence list is removed from future consideration. + + All virtual references are lumped together. Any expression which is + dependent on any virtual variable (via a VUSE) has a dependence added + to the special partition defined by VIRTUAL_PARTITION. + + Whenever a V_MAY_DEF is seen, all expressions dependent this + VIRTUAL_PARTITION are removed from consideration. + + At the end of a basic block, all expression are removed from consideration + in preparation for the next block. + + The end result is a vector over SSA_NAME_VERSION which is passed back to + rewrite_out_of_ssa. As the SSA variables are being rewritten, instead of + replacing the SSA_NAME tree element with the partition it was assigned, + it is replaced with the RHS of the defining expression. */ + + +/* Dependency list element. This can contain either a partition index or a + version number, depending on which list it is in. */ + +typedef struct value_expr_d +{ + int value; + struct value_expr_d *next; +} *value_expr_p; + + +/* Temporary Expression Replacement (TER) table information. */ + +typedef struct temp_expr_table_d +{ + var_map map; + void **version_info; + value_expr_p *partition_dep_list; + bitmap replaceable; + bool saw_replaceable; + int virtual_partition; + bitmap partition_in_use; + value_expr_p free_list; + value_expr_p pending_dependence; +} *temp_expr_table_p; + +/* Used to indicate a dependency on V_MAY_DEFs. */ +#define VIRTUAL_PARTITION(table) (table->virtual_partition) + +static temp_expr_table_p new_temp_expr_table (var_map); +static tree *free_temp_expr_table (temp_expr_table_p); +static inline value_expr_p new_value_expr (temp_expr_table_p); +static inline void free_value_expr (temp_expr_table_p, value_expr_p); +static inline value_expr_p find_value_in_list (value_expr_p, int, + value_expr_p *); +static inline void add_value_to_list (temp_expr_table_p, value_expr_p *, int); +static inline void add_info_to_list (temp_expr_table_p, value_expr_p *, + value_expr_p); +static value_expr_p remove_value_from_list (value_expr_p *, int); +static void add_dependance (temp_expr_table_p, int, tree); +static bool check_replaceable (temp_expr_table_p, tree); +static void finish_expr (temp_expr_table_p, int, bool); +static void mark_replaceable (temp_expr_table_p, tree); +static inline void kill_expr (temp_expr_table_p, int, bool); +static inline void kill_virtual_exprs (temp_expr_table_p, bool); +static void find_replaceable_in_bb (temp_expr_table_p, basic_block); +static tree *find_replaceable_exprs (var_map); +static void dump_replaceable_exprs (FILE *, tree *); + + +/* Create a new TER table for MAP. */ + +static temp_expr_table_p +new_temp_expr_table (var_map map) +{ + temp_expr_table_p t; + + t = (temp_expr_table_p) xmalloc (sizeof (struct temp_expr_table_d)); + t->map = map; + + t->version_info = xcalloc (num_ssa_names + 1, sizeof (void *)); + t->partition_dep_list = xcalloc (num_var_partitions (map) + 1, + sizeof (value_expr_p)); + + t->replaceable = BITMAP_XMALLOC (); + t->partition_in_use = BITMAP_XMALLOC (); + + t->saw_replaceable = false; + t->virtual_partition = num_var_partitions (map); + t->free_list = NULL; + t->pending_dependence = NULL; + + return t; +} + + +/* Free TER table T. If there are valid replacements, return the expression + vector. */ + +static tree * +free_temp_expr_table (temp_expr_table_p t) +{ + value_expr_p p; + tree *ret = NULL; + +#ifdef ENABLE_CHECKING + int x; + for (x = 0; x <= num_var_partitions (t->map); x++) + if (t->partition_dep_list[x] != NULL) + abort(); +#endif + + while ((p = t->free_list)) + { + t->free_list = p->next; + free (p); + } + + BITMAP_XFREE (t->partition_in_use); + BITMAP_XFREE (t->replaceable); + + free (t->partition_dep_list); + if (t->saw_replaceable) + ret = (tree *)t->version_info; + else + free (t->version_info); + + free (t); + return ret; +} + + +/* Allocate a new value list node. Take it from the free list in TABLE if + possible. */ + +static inline value_expr_p +new_value_expr (temp_expr_table_p table) +{ + value_expr_p p; + if (table->free_list) + { + p = table->free_list; + table->free_list = p->next; + } + else + p = (value_expr_p) xmalloc (sizeof (struct value_expr_d)); + + return p; +} + + +/* Add value list node P to the free list in TABLE. */ + +static inline void +free_value_expr (temp_expr_table_p table, value_expr_p p) +{ + p->next = table->free_list; + table->free_list = p; +} + + +/* Find VALUE if its in LIST. Return a pointer to the list object if found, + else return NULL. If LAST_PTR is provided, it will point to the previous + item upon return, or NULL if this is the first item in the list. */ + +static inline value_expr_p +find_value_in_list (value_expr_p list, int value, value_expr_p *last_ptr) +{ + value_expr_p curr; + value_expr_p last = NULL; + + for (curr = list; curr; last = curr, curr = curr->next) + { + if (curr->value == value) + break; + } + if (last_ptr) + *last_ptr = last; + return curr; +} + + +/* Add VALUE to LIST, if it isn't already present. TAB is the expression + table */ + +static inline void +add_value_to_list (temp_expr_table_p tab, value_expr_p *list, int value) +{ + value_expr_p info; + + if (!find_value_in_list (*list, value, NULL)) + { + info = new_value_expr (tab); + info->value = value; + info->next = *list; + *list = info; + } +} + + +/* Add value node INFO if it's value isn't already in LIST. Free INFO if + it is already in the list. TAB is the expression table. */ + +static inline void +add_info_to_list (temp_expr_table_p tab, value_expr_p *list, value_expr_p info) +{ + if (find_value_in_list (*list, info->value, NULL)) + free_value_expr (tab, info); + else + { + info->next = *list; + *list = info; + } +} + + +/* Look for VALUE in LIST. If found, remove it from the list and return it's + pointer. */ + +static value_expr_p +remove_value_from_list (value_expr_p *list, int value) +{ + value_expr_p info, last; + + info = find_value_in_list (*list, value, &last); + if (!info) + return NULL; + if (!last) + *list = info->next; + else + last->next = info->next; + + return info; +} + + +/* Add a dependency between the def of ssa VERSION and VAR. If VAR is + replaceable by an expression, add a dependence each of the elements of the + expression. These are contained in the pending list. TAB is the + expression table. */ + +static void +add_dependance (temp_expr_table_p tab, int version, tree var) +{ + int i, x; + value_expr_p info; + + i = SSA_NAME_VERSION (var); + if (bitmap_bit_p (tab->replaceable, i)) + { + /* This variable is being substituted, so use whatever dependences + were queued up when we marked this as replaceable earlier. */ + while ((info = tab->pending_dependence)) + { + tab->pending_dependence = info->next; + /* Get the partition this variable was dependent on. Reuse this + object to represent the current expression instead. */ + x = info->value; + info->value = version; + add_info_to_list (tab, &(tab->partition_dep_list[x]), info); + add_value_to_list (tab, + (value_expr_p *)&(tab->version_info[version]), x); + bitmap_set_bit (tab->partition_in_use, x); + } + } + else + { + i = var_to_partition (tab->map, var); +#ifdef ENABLE_CHECKING + if (i== NO_PARTITION) + abort (); +#endif + add_value_to_list (tab, &(tab->partition_dep_list[i]), version); + add_value_to_list (tab, + (value_expr_p *)&(tab->version_info[version]), i); + bitmap_set_bit (tab->partition_in_use, i); + } +} + + +/* Check if expression STMT is suitable for replacement in table TAB. If so, + create an expression entry. Return true if this stmt is replaceable. */ + +static bool +check_replaceable (temp_expr_table_p tab, tree stmt) +{ + stmt_ann_t ann; + vuse_optype vuseops; + def_optype defs; + use_optype uses; + tree var, def; + int num_use_ops, version, i; + var_map map = tab->map; + + if (TREE_CODE (stmt) != MODIFY_EXPR) + return false; + + ann = stmt_ann (stmt); + defs = DEF_OPS (ann); + + /* Punt if there is more than 1 def, or more than 1 use. */ + if (NUM_DEFS (defs) != 1) + return false; + def = DEF_OP (defs, 0); + if (version_ref_count (map, def) != 1) + return false; + + /* Assignments to variables assigned to hard registers are not + replaceable. */ + if (DECL_HARD_REGISTER (SSA_NAME_VAR (def))) + return false; + + /* There must be no V_MAY_DEFS. */ + if (NUM_V_MAY_DEFS (V_MAY_DEF_OPS (ann)) != 0) + return false; + + /* There must be no V_MUST_DEFS. */ + if (NUM_V_MUST_DEFS (V_MUST_DEF_OPS (ann)) != 0) + return false; + + /* Float expressions must go through memory if float-store is on. */ + if (flag_float_store && FLOAT_TYPE_P (TREE_TYPE (TREE_OPERAND (stmt, 1)))) + return false; + + uses = USE_OPS (ann); + num_use_ops = NUM_USES (uses); + vuseops = VUSE_OPS (ann); + + /* Any expression which has no virtual operands and no real operands + should have been propagated if it's possible to do anything with them. + If this happens here, it probably exists that way for a reason, so we + won't touch it. An example is: + b_4 = &tab + There are no virtual uses nor any real uses, so we just leave this + alone to be safe. */ + + if (num_use_ops == 0 && NUM_VUSES (vuseops) == 0) + return false; + + version = SSA_NAME_VERSION (def); + + /* Add this expression to the dependency list for each use partition. */ + for (i = 0; i < num_use_ops; i++) + { + var = USE_OP (uses, i); + add_dependance (tab, version, var); + } + + /* If there are VUSES, add a dependence on virtual defs. */ + if (NUM_VUSES (vuseops) != 0) + { + add_value_to_list (tab, (value_expr_p *)&(tab->version_info[version]), + VIRTUAL_PARTITION (tab)); + add_value_to_list (tab, + &(tab->partition_dep_list[VIRTUAL_PARTITION (tab)]), + version); + bitmap_set_bit (tab->partition_in_use, VIRTUAL_PARTITION (tab)); + } + + return true; +} + + +/* This function will remove the expression for VERSION from replacement + consideration.n table TAB If 'replace' is true, it is marked as + replaceable, otherwise not. */ + +static void +finish_expr (temp_expr_table_p tab, int version, bool replace) +{ + value_expr_p info, tmp; + int partition; + + /* Remove this expression from its dependent lists. The partition dependence + list is retained and transfered later to whomever uses this version. */ + for (info = (value_expr_p) tab->version_info[version]; info; info = tmp) + { + partition = info->value; +#ifdef ENABLE_CHECKING + if (tab->partition_dep_list[partition] == NULL) + abort (); +#endif + tmp = remove_value_from_list (&(tab->partition_dep_list[partition]), + version); +#ifdef ENABLE_CHECKING + if (!tmp) + abort (); +#endif + free_value_expr (tab, tmp); + /* Only clear the bit when the dependency list is emptied via + a replacement. Otherwise kill_expr will take care of it. */ + if (!(tab->partition_dep_list[partition]) && replace) + bitmap_clear_bit (tab->partition_in_use, partition); + tmp = info->next; + if (!replace) + free_value_expr (tab, info); + } + + if (replace) + { + tab->saw_replaceable = true; + bitmap_set_bit (tab->replaceable, version); + } + else + { +#ifdef ENABLE_CHECKING + if (bitmap_bit_p (tab->replaceable, version)) + abort (); +#endif + tab->version_info[version] = NULL; + } +} + + +/* Mark the expression associated with VAR as replaceable, and enter + the defining stmt into the version_info table TAB. */ + +static void +mark_replaceable (temp_expr_table_p tab, tree var) +{ + value_expr_p info; + int version = SSA_NAME_VERSION (var); + finish_expr (tab, version, true); + + /* Move the dependence list to the pending list. */ + if (tab->version_info[version]) + { + info = (value_expr_p) tab->version_info[version]; + for ( ; info->next; info = info->next) + continue; + info->next = tab->pending_dependence; + tab->pending_dependence = (value_expr_p)tab->version_info[version]; + } + + tab->version_info[version] = SSA_NAME_DEF_STMT (var); +} + + +/* This function marks any expression in TAB which is dependent on PARTITION + as NOT replaceable. CLEAR_BIT is used to determine whether partition_in_use + should have its bit cleared. Since this routine can be called within an + EXECUTE_IF_SET_IN_BITMAP, the bit can't always be cleared. */ + +static inline void +kill_expr (temp_expr_table_p tab, int partition, bool clear_bit) +{ + value_expr_p ptr; + + /* Mark every active expr dependent on this var as not replaceable. */ + while ((ptr = tab->partition_dep_list[partition]) != NULL) + finish_expr (tab, ptr->value, false); + + if (clear_bit) + bitmap_clear_bit (tab->partition_in_use, partition); +} + + +/* This function kills all expressions in TAB which are dependent on virtual + DEFs. CLEAR_BIT determines whether partition_in_use gets cleared. */ + +static inline void +kill_virtual_exprs (temp_expr_table_p tab, bool clear_bit) +{ + kill_expr (tab, VIRTUAL_PARTITION (tab), clear_bit); +} + + +/* This function processes basic block BB, and looks for variables which can + be replaced by their expressions. Results are stored in TAB. */ + +static void +find_replaceable_in_bb (temp_expr_table_p tab, basic_block bb) +{ + block_stmt_iterator bsi; + tree stmt, def; + stmt_ann_t ann; + int partition, num, i; + use_optype uses; + def_optype defs; + var_map map = tab->map; + value_expr_p p; + + for (bsi = bsi_start (bb); !bsi_end_p (bsi); bsi_next (&bsi)) + { + stmt = bsi_stmt (bsi); + ann = stmt_ann (stmt); + + /* Determine if this stmt finishes an existing expression. */ + uses = USE_OPS (ann); + num = NUM_USES (uses); + for (i = 0; i < num; i++) + { + def = USE_OP (uses, i); + if (tab->version_info[SSA_NAME_VERSION (def)]) + { + /* Mark expression as replaceable unless stmt is volatile. */ + if (!ann->has_volatile_ops) + mark_replaceable (tab, def); + else + finish_expr (tab, SSA_NAME_VERSION (def), false); + } + } + + /* Next, see if this stmt kills off an active expression. */ + defs = DEF_OPS (ann); + num = NUM_DEFS (defs); + for (i = 0; i < num; i++) + { + def = DEF_OP (defs, i); + partition = var_to_partition (map, def); + if (partition != NO_PARTITION && tab->partition_dep_list[partition]) + kill_expr (tab, partition, true); + } + + /* Now see if we are creating a new expression or not. */ + if (!ann->has_volatile_ops) + check_replaceable (tab, stmt); + + /* Free any unused dependency lists. */ + while ((p = tab->pending_dependence)) + { + tab->pending_dependence = p->next; + free_value_expr (tab, p); + } + + /* A V_MAY_DEF kills any expression using a virtual operand. */ + if (NUM_V_MAY_DEFS (V_MAY_DEF_OPS (ann)) > 0) + kill_virtual_exprs (tab, true); + + /* A V_MUST_DEF kills any expression using a virtual operand. */ + if (NUM_V_MUST_DEFS (V_MUST_DEF_OPS (ann)) > 0) + kill_virtual_exprs (tab, true); + } +} + + +/* This function is the driver routine for replacement of temporary expressions + in the SSA->normal phase, operating on MAP. If there are replaceable + expressions, a table is returned which maps SSA versions to the + expressions they should be replaced with. A NULL_TREE indicates no + replacement should take place. If there are no replacements at all, + NULL is returned by the function, otherwise an expression vector indexed + by SSA_NAME version numbers. */ + +static tree * +find_replaceable_exprs (var_map map) +{ + basic_block bb; + int i; + temp_expr_table_p table; + tree *ret; + + table = new_temp_expr_table (map); + FOR_EACH_BB (bb) + { + find_replaceable_in_bb (table, bb); + EXECUTE_IF_SET_IN_BITMAP ((table->partition_in_use), 0, i, + { + kill_expr (table, i, false); + }); + } + + ret = free_temp_expr_table (table); + return ret; +} + + +/* Dump TER expression table EXPR to file F. */ + +static void +dump_replaceable_exprs (FILE *f, tree *expr) +{ + tree stmt, var; + int x; + fprintf (f, "\nReplacing Expressions\n"); + for (x = 0; x < (int)num_ssa_names + 1; x++) + if (expr[x]) + { + stmt = expr[x]; + var = DEF_OP (STMT_DEF_OPS (stmt), 0); + print_generic_expr (f, var, TDF_SLIM); + fprintf (f, " replace with --> "); + print_generic_expr (f, TREE_OPERAND (stmt, 1), TDF_SLIM); + fprintf (f, "\n"); + } + fprintf (f, "\n"); +} + + +/* Helper function for discover_nonconstant_array_refs. + Look for ARRAY_REF nodes with non-constant indexes and mark them + addressable. */ + +static tree +discover_nonconstant_array_refs_r (tree * tp, int *walk_subtrees, + void *data ATTRIBUTE_UNUSED) +{ + tree t = *tp; + + if (TYPE_P (t) || DECL_P (t)) + *walk_subtrees = 0; + else if (TREE_CODE (t) == ARRAY_REF || TREE_CODE (t) == ARRAY_RANGE_REF) + { + while (((TREE_CODE (t) == ARRAY_REF || TREE_CODE (t) == ARRAY_RANGE_REF) + && is_gimple_min_invariant (TREE_OPERAND (t, 1)) + && (!TREE_OPERAND (t, 2) + || is_gimple_min_invariant (TREE_OPERAND (t, 2)))) + || (TREE_CODE (t) == COMPONENT_REF + && (!TREE_OPERAND (t,2) + || is_gimple_min_invariant (TREE_OPERAND (t, 2)))) + || TREE_CODE (t) == BIT_FIELD_REF + || TREE_CODE (t) == REALPART_EXPR + || TREE_CODE (t) == IMAGPART_EXPR + || TREE_CODE (t) == VIEW_CONVERT_EXPR + || TREE_CODE (t) == NOP_EXPR + || TREE_CODE (t) == CONVERT_EXPR) + t = TREE_OPERAND (t, 0); + + if (TREE_CODE (t) == ARRAY_REF || TREE_CODE (t) == ARRAY_RANGE_REF) + { + t = get_base_address (t); + if (t && DECL_P (t)) + TREE_ADDRESSABLE (t) = 1; + } + + *walk_subtrees = 0; + } + + return NULL_TREE; +} + + +/* RTL expansion is not able to compile array references with variable + offsets for arrays stored in single register. Discover such + expressions and mark variables as addressable to avoid this + scenario. */ + +static void +discover_nonconstant_array_refs (void) +{ + basic_block bb; + block_stmt_iterator bsi; + + FOR_EACH_BB (bb) + { + for (bsi = bsi_start (bb); !bsi_end_p (bsi); bsi_next (&bsi)) + walk_tree (bsi_stmt_ptr (bsi), discover_nonconstant_array_refs_r, + NULL , NULL); + } +} + + +/* This function will rewrite the current program using the variable mapping + found in MAP. If the replacement vector VALUES is provided, any + occurrences of partitions with non-null entries in the vector will be + replaced with the expression in the vector instead of its mapped + variable. */ + +static void +rewrite_trees (var_map map, tree *values) +{ + elim_graph g; + basic_block bb; + block_stmt_iterator si; + edge e; + tree phi; + bool changed; + +#ifdef ENABLE_CHECKING + /* Search for PHIs where the destination has no partition, but one + or more arguments has a partition. This should not happen and can + create incorrect code. */ + FOR_EACH_BB (bb) + { + tree phi; + + for (phi = phi_nodes (bb); phi; phi = PHI_CHAIN (phi)) + { + tree T0 = var_to_partition_to_var (map, PHI_RESULT (phi)); + + if (T0 == NULL_TREE) + { + int i; + + for (i = 0; i < PHI_NUM_ARGS (phi); i++) + { + tree arg = PHI_ARG_DEF (phi, i); + + if (TREE_CODE (arg) == SSA_NAME + && var_to_partition (map, arg) != NO_PARTITION) + { + fprintf (stderr, "Argument of PHI is in a partition :("); + print_generic_expr (stderr, arg, TDF_SLIM); + fprintf (stderr, "), but the result is not :"); + print_generic_stmt (stderr, phi, TDF_SLIM); + abort(); + } + } + } + } + } +#endif + + /* Replace PHI nodes with any required copies. */ + g = new_elim_graph (map->num_partitions); + g->map = map; + FOR_EACH_BB (bb) + { + for (si = bsi_start (bb); !bsi_end_p (si); ) + { + size_t i, num_uses, num_defs; + use_optype uses; + def_optype defs; + tree stmt = bsi_stmt (si); + use_operand_p use_p; + int remove = 0, is_copy = 0; + stmt_ann_t ann; + + get_stmt_operands (stmt); + ann = stmt_ann (stmt); + changed = false; + + if (TREE_CODE (stmt) == MODIFY_EXPR + && (TREE_CODE (TREE_OPERAND (stmt, 1)) == SSA_NAME)) + is_copy = 1; + + uses = USE_OPS (ann); + num_uses = NUM_USES (uses); + + for (i = 0; i < num_uses; i++) + { + use_p = USE_OP_PTR (uses, i); + if (replace_use_variable (map, use_p, values)) + changed = true; + } + + defs = DEF_OPS (ann); + num_defs = NUM_DEFS (defs); + + /* Mark this stmt for removal if it is the list of replaceable + expressions. */ + if (values && num_defs == 1) + { + tree def = DEF_OP (defs, 0); + tree val; + val = values[SSA_NAME_VERSION (def)]; + if (val) + remove = 1; + } + if (!remove) + { + for (i = 0; i < num_defs; i++) + { + def_operand_p def_p = DEF_OP_PTR (defs, i); + + if (replace_def_variable (map, def_p, NULL)) + changed = true; + + /* If both SSA_NAMEs coalesce to the same variable, + mark the now redundant copy for removal. */ + if (is_copy + && num_uses == 1 + && (DEF_FROM_PTR (def_p) == USE_OP (uses, 0))) + remove = 1; + } + if (changed) + modify_stmt (stmt); + } + + /* Remove any stmts marked for removal. */ + if (remove) + bsi_remove (&si); + else + bsi_next (&si); + } + + phi = phi_nodes (bb); + if (phi) + { + for (e = bb->pred; e; e = e->pred_next) + eliminate_phi (e, phi_arg_from_edge (phi, e), g); + } + } + + delete_elim_graph (g); + + /* If any copies were inserted on edges, actually insert them now. */ + bsi_commit_edge_inserts (NULL); +} + + +/* Remove the variables specified in MAP from SSA form. Any debug information + is sent to DUMP. FLAGS indicate what options should be used. */ + +void +remove_ssa_form (FILE *dump, var_map map, int flags) +{ + tree_live_info_p liveinfo; + basic_block bb; + tree phi, next; + FILE *save; + tree *values = NULL; + + save = dump_file; + dump_file = dump; + + /* If we are not combining temps, don't calculate live ranges for variables + with only one SSA version. */ + if ((flags & SSANORM_COMBINE_TEMPS) == 0) + compact_var_map (map, VARMAP_NO_SINGLE_DEFS); + else + compact_var_map (map, VARMAP_NORMAL); + + if (dump_file && (dump_flags & TDF_DETAILS)) + dump_var_map (dump_file, map); + + liveinfo = coalesce_ssa_name (map, flags); + + /* Make sure even single occurrence variables are in the list now. */ + if ((flags & SSANORM_COMBINE_TEMPS) == 0) + compact_var_map (map, VARMAP_NORMAL); + + if (dump_file && (dump_flags & TDF_DETAILS)) + { + fprintf (dump_file, "After Coalescing:\n"); + dump_var_map (dump_file, map); + } + + if (flags & SSANORM_PERFORM_TER) + { + values = find_replaceable_exprs (map); + if (values && dump_file && (dump_flags & TDF_DETAILS)) + dump_replaceable_exprs (dump_file, values); + } + + /* Assign real variables to the partitions now. */ + assign_vars (map); + + if (dump_file && (dump_flags & TDF_DETAILS)) + { + fprintf (dump_file, "After Root variable replacement:\n"); + dump_var_map (dump_file, map); + } + + if ((flags & SSANORM_COMBINE_TEMPS) && liveinfo) + { + coalesce_vars (map, liveinfo); + if (dump_file && (dump_flags & TDF_DETAILS)) + { + fprintf (dump_file, "After variable memory coalescing:\n"); + dump_var_map (dump_file, map); + } + } + + if (liveinfo) + delete_tree_live_info (liveinfo); + + rewrite_trees (map, values); + + if (values) + free (values); + + /* Remove phi nodes which have been translated back to real variables. */ + FOR_EACH_BB (bb) + { + for (phi = phi_nodes (bb); phi; phi = next) + { + next = PHI_CHAIN (phi); + if ((flags & SSANORM_REMOVE_ALL_PHIS) + || var_to_partition (map, PHI_RESULT (phi)) != NO_PARTITION) + remove_phi_node (phi, NULL_TREE, bb); + } + } + + dump_file = save; +} + + +/* Take a subset of the variables VARS in the current function out of SSA + form. */ + +void +rewrite_vars_out_of_ssa (bitmap vars) +{ + if (bitmap_first_set_bit (vars) >= 0) + { + var_map map; + basic_block bb; + tree phi; + int i; + int ssa_flags; + + /* Search for PHIs in which one of the PHI arguments is marked for + translation out of SSA form, but for which the PHI result is not + marked for translation out of SSA form. + + Our per-variable out of SSA translation can not handle that case; + however we can easily handle it here by creating a new instance + of the PHI result's underlying variable and initializing it to + the offending PHI argument on the edge associated with the + PHI argument. We then change the PHI argument to use our new + instead of the PHI's underlying variable. + + You might think we could register partitions for the out-of-ssa + translation here and avoid a second walk of the PHI nodes. No + such luck since the size of the var map will change if we have + to manually take variables out of SSA form here. */ + FOR_EACH_BB (bb) + { + for (phi = phi_nodes (bb); phi; phi = PHI_CHAIN (phi)) + { + tree result = SSA_NAME_VAR (PHI_RESULT (phi)); + + /* If the definition is marked for renaming, then we need + to do nothing more for this PHI node. */ + if (bitmap_bit_p (vars, var_ann (result)->uid)) + continue; + + /* Look at all the arguments and see if any of them are + marked for renaming. If so, we need to handle them + specially. */ + for (i = 0; i < PHI_NUM_ARGS (phi); i++) + { + tree arg = PHI_ARG_DEF (phi, i); + + /* If the argument is not an SSA_NAME, then we can ignore + this argument. */ + if (TREE_CODE (arg) != SSA_NAME) + continue; + + /* If this argument is marked for renaming, then we need + to undo the copy propagation so that we can take + the argument out of SSA form without taking the + result out of SSA form. */ + arg = SSA_NAME_VAR (arg); + if (bitmap_bit_p (vars, var_ann (arg)->uid)) + { + tree new_name, copy; + + /* Get a new SSA_NAME for the copy, it is based on + the result, not the argument! We use the PHI + as the definition since we haven't created the + definition statement yet. */ + new_name = make_ssa_name (result, phi); + + /* Now create the copy statement. */ + copy = build (MODIFY_EXPR, TREE_TYPE (arg), + new_name, PHI_ARG_DEF (phi, i)); + + /* Now update SSA_NAME_DEF_STMT to point to the + newly created statement. */ + SSA_NAME_DEF_STMT (new_name) = copy; + + /* Now make the argument reference our new SSA_NAME. */ + SET_PHI_ARG_DEF (phi, i, new_name); + + /* Queue the statement for insertion. */ + bsi_insert_on_edge (PHI_ARG_EDGE (phi, i), copy); + modify_stmt (copy); + } + } + } + } + + /* If any copies were inserted on edges, actually insert them now. */ + bsi_commit_edge_inserts (NULL); + + /* Now register partitions for all instances of the variables we + are taking out of SSA form. */ + map = init_var_map (num_ssa_names + 1); + register_ssa_partitions_for_vars (vars, map); + + /* Now that we have all the partitions registered, translate the + appropriate variables out of SSA form. */ + ssa_flags = SSANORM_COALESCE_PARTITIONS; + if (flag_tree_combine_temps) + ssa_flags |= SSANORM_COMBINE_TEMPS; + remove_ssa_form (dump_file, map, ssa_flags); + + /* And finally, reset the out_of_ssa flag for each of the vars + we just took out of SSA form. */ + EXECUTE_IF_SET_IN_BITMAP (vars, 0, i, + { + var_ann (referenced_var (i))->out_of_ssa_tag = 0; + }); + + /* Free the map as we are done with it. */ + delete_var_map (map); + + } +} + + +/* Take the current function out of SSA form, as described in + R. Morgan, ``Building an Optimizing Compiler'', + Butterworth-Heinemann, Boston, MA, 1998. pp 176-186. */ + +static void +rewrite_out_of_ssa (void) +{ + var_map map; + int var_flags = 0; + int ssa_flags = (SSANORM_REMOVE_ALL_PHIS | SSANORM_USE_COALESCE_LIST); + + if (!flag_tree_live_range_split) + ssa_flags |= SSANORM_COALESCE_PARTITIONS; + + eliminate_virtual_phis (); + + if (dump_file && (dump_flags & TDF_DETAILS)) + dump_tree_cfg (dump_file, dump_flags & ~TDF_DETAILS); + + /* We cannot allow unssa to un-gimplify trees before we instrument them. */ + if (flag_tree_ter && !flag_mudflap) + var_flags = SSA_VAR_MAP_REF_COUNT; + + map = create_ssa_var_map (var_flags); + + if (flag_tree_combine_temps) + ssa_flags |= SSANORM_COMBINE_TEMPS; + if (flag_tree_ter && !flag_mudflap) + ssa_flags |= SSANORM_PERFORM_TER; + + remove_ssa_form (dump_file, map, ssa_flags); + + if (dump_file && (dump_flags & TDF_DETAILS)) + dump_tree_cfg (dump_file, dump_flags & ~TDF_DETAILS); + + /* Do some cleanups which reduce the amount of data the + tree->rtl expanders deal with. */ + cfg_remove_useless_stmts (); + + /* Flush out flow graph and SSA data. */ + delete_var_map (map); + + /* Mark arrays indexed with non-constant indices with TREE_ADDRESSABLE. */ + discover_nonconstant_array_refs (); +} + + +/* Define the parameters of the out of SSA pass. */ + +struct tree_opt_pass pass_del_ssa = +{ + "optimized", /* name */ + NULL, /* gate */ + rewrite_out_of_ssa, /* execute */ + NULL, /* sub */ + NULL, /* next */ + 0, /* static_pass_number */ + TV_TREE_SSA_TO_NORMAL, /* tv_id */ + PROP_cfg | PROP_ssa, /* properties_required */ + 0, /* properties_provided */ + /* ??? If TER is enabled, we also kill gimple. */ + PROP_ssa, /* properties_destroyed */ + TODO_verify_ssa | TODO_verify_flow + | TODO_verify_stmts, /* todo_flags_start */ + TODO_dump_func | TODO_ggc_collect /* todo_flags_finish */ +}; |