/* Convert a program in SSA form into Normal form.
- Copyright (C) 2004 Free Software Foundation, Inc.
+ Copyright (C) 2004, 2005, 2006, 2007, 2008 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)
+the Free Software Foundation; either version 3, or (at your option)
any later version.
GCC is distributed in the hope that it will be useful,
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. */
+along with GCC; see the file COPYING3. If not see
+<http://www.gnu.org/licenses/>. */
#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 "hashtab.h"
#include "tree-dump.h"
#include "tree-ssa-live.h"
#include "tree-pass.h"
+#include "toplev.h"
-/* Flags to pass to remove_ssa_form. */
-
-#define SSANORM_PERFORM_TER 0x1
-#define SSANORM_COMBINE_TEMPS 0x2
-#define SSANORM_REMOVE_ALL_PHIS 0x4
-#define SSANORM_COALESCE_PARTITIONS 0x8
-#define SSANORM_USE_COALESCE_LIST 0x10
/* 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
int size;
/* List of nodes in the elimination graph. */
- varray_type nodes;
+ VEC(tree,heap) *nodes;
/* The predecessor and successor edge list. */
- varray_type edge_list;
+ VEC(int,heap) *edge_list;
/* Visited vector. */
sbitmap visited;
/* Stack for visited nodes. */
- varray_type stack;
+ VEC(int,heap) *stack;
/* The variable partition map. */
var_map map;
edge e;
/* List of constant copies to emit. These are pushed on in pairs. */
- varray_type const_copies;
+ VEC(tree,heap) *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. */
if (name == NULL)
name = "temp";
tmp = create_tmp_var (type, name);
+
+ if (DECL_DEBUG_EXPR_IS_FROM (t) && DECL_DEBUG_EXPR (t))
+ {
+ SET_DECL_DEBUG_EXPR (tmp, DECL_DEBUG_EXPR (t));
+ DECL_DEBUG_EXPR_IS_FROM (tmp) = 1;
+ }
+ else if (!DECL_IGNORED_P (t))
+ {
+ SET_DECL_DEBUG_EXPR (tmp, t);
+ DECL_DEBUG_EXPR_IS_FROM (tmp) = 1;
+ }
DECL_ARTIFICIAL (tmp) = DECL_ARTIFICIAL (t);
- add_referenced_tmp_var (tmp);
+ DECL_IGNORED_P (tmp) = DECL_IGNORED_P (t);
+ DECL_GIMPLE_REG_P (tmp) = DECL_GIMPLE_REG_P (t);
+ add_referenced_var (tmp);
- /* add_referenced_tmp_var will create the annotation and set up some
+ /* add_referenced_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;
+ set_symbol_mem_tag (tmp, symbol_mem_tag (t));
if (is_call_clobbered (t))
- mark_call_clobbered (tmp);
+ mark_call_clobbered (tmp, var_ann (t)->escape_mask);
return tmp;
}
{
tree copy;
- copy = build (MODIFY_EXPR, TREE_TYPE (dest), dest, src);
+ copy = build_gimple_modify_stmt (dest, src);
set_is_used (dest);
if (TREE_CODE (src) == ADDR_EXPR)
{
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->nodes = VEC_alloc (tree, heap, 30);
+ g->const_copies = VEC_alloc (tree, heap, 20);
+ g->edge_list = VEC_alloc (int, heap, 20);
+ g->stack = VEC_alloc (int, heap, 30);
g->visited = sbitmap_alloc (size);
static inline void
clear_elim_graph (elim_graph g)
{
- VARRAY_POP_ALL (g->nodes);
- VARRAY_POP_ALL (g->edge_list);
+ VEC_truncate (tree, g->nodes, 0);
+ VEC_truncate (int, g->edge_list, 0);
}
delete_elim_graph (elim_graph g)
{
sbitmap_free (g->visited);
+ VEC_free (int, heap, g->stack);
+ VEC_free (int, heap, g->edge_list);
+ VEC_free (tree, heap, g->const_copies);
+ VEC_free (tree, heap, g->nodes);
free (g);
}
static inline int
elim_graph_size (elim_graph g)
{
- return VARRAY_ACTIVE_SIZE (g->nodes);
+ return VEC_length (tree, g->nodes);
}
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)
+ tree t;
+
+ for (x = 0; VEC_iterate (tree, g->nodes, x, t); x++)
+ if (t == node)
return;
- VARRAY_PUSH_TREE (g->nodes, node);
+ VEC_safe_push (tree, heap, g->nodes, node);
}
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);
+ VEC_safe_push (int, heap, g->edge_list, pred);
+ VEC_safe_push (int, heap, g->edge_list, succ);
}
{
int y;
unsigned x;
- for (x = 0; x < VARRAY_ACTIVE_SIZE (g->edge_list); x += 2)
- if (VARRAY_INT (g->edge_list, x) == node)
+ for (x = 0; x < VEC_length (int, g->edge_list); x += 2)
+ if (VEC_index (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;
+ VEC_replace (int, g->edge_list, x, -1);
+ y = VEC_index (int, g->edge_list, x + 1);
+ VEC_replace (int, g->edge_list, x + 1, -1);
return y;
}
return -1;
do { \
unsigned x_; \
int y_; \
- for (x_ = 0; x_ < VARRAY_ACTIVE_SIZE ((GRAPH)->edge_list); x_ += 2) \
+ for (x_ = 0; x_ < VEC_length (int, (GRAPH)->edge_list); x_ += 2) \
{ \
- y_ = VARRAY_INT ((GRAPH)->edge_list, x_); \
+ y_ = VEC_index (int, (GRAPH)->edge_list, x_); \
if (y_ != (NODE)) \
continue; \
- (VAR) = VARRAY_INT ((GRAPH)->edge_list, x_ + 1); \
+ (VAR) = VEC_index (int, (GRAPH)->edge_list, x_ + 1); \
CODE; \
} \
} while (0)
do { \
unsigned x_; \
int y_; \
- for (x_ = 0; x_ < VARRAY_ACTIVE_SIZE ((GRAPH)->edge_list); x_ += 2) \
+ for (x_ = 0; x_ < VEC_length (int, (GRAPH)->edge_list); x_ += 2) \
{ \
- y_ = VARRAY_INT ((GRAPH)->edge_list, x_ + 1); \
+ y_ = VEC_index (int, (GRAPH)->edge_list, x_ + 1); \
if (y_ != (NODE)) \
continue; \
- (VAR) = VARRAY_INT ((GRAPH)->edge_list, x_); \
+ (VAR) = VEC_index (int, (GRAPH)->edge_list, x_); \
CODE; \
} \
} while (0)
}
-/* Build elimination graph G for basic block BB on incoming PHI edge I. */
+/* Build elimination graph G for basic block BB on incoming PHI edge
+ G->e. */
static void
-eliminate_build (elim_graph g, basic_block B, int i)
+eliminate_build (elim_graph g, basic_block B)
{
tree phi;
tree T0, Ti;
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);
- gcc_assert (pi != -1);
- Ti = PHI_ARG_DEF (phi, pi);
- }
+ Ti = PHI_ARG_DEF (phi, g->e->dest_idx);
/* 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
{
/* 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);
+ VEC_safe_push (tree, heap, g->const_copies, T0);
+ VEC_safe_push (tree, heap, g->const_copies, Ti);
}
else
{
if (!TEST_BIT (g->visited, S))
elim_forward (g, S);
});
- VARRAY_PUSH_INT (g->stack, T);
+ VEC_safe_push (int, heap, g->stack, T);
}
}
-/* 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. */
+
+/* Eliminate all the phi nodes on edge E in graph G. */
static void
-eliminate_phi (edge e, int i, elim_graph g)
+eliminate_phi (edge e, elim_graph g)
{
- int num_nodes = 0;
int x;
basic_block B = e->dest;
- gcc_assert (i != -1);
- gcc_assert (VARRAY_ACTIVE_SIZE (g->const_copies) == 0);
+ gcc_assert (VEC_length (tree, g->const_copies) == 0);
- /* Abnormal edges already have everything coalesced, or the coalescer
- would have aborted. */
+ /* Abnormal edges already have everything coalesced. */
if (e->flags & EDGE_ABNORMAL)
return;
- num_nodes = num_var_partitions (g->map);
g->e = e;
- eliminate_build (g, B, i);
+ eliminate_build (g, B);
if (elim_graph_size (g) != 0)
{
+ tree var;
+
sbitmap_zero (g->visited);
- VARRAY_POP_ALL (g->stack);
+ VEC_truncate (int, g->stack, 0);
- for (x = 0; x < elim_graph_size (g); x++)
+ for (x = 0; VEC_iterate (tree, g->nodes, x, var); 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)
+ while (VEC_length (int, g->stack) > 0)
{
- x = VARRAY_TOP_INT (g->stack);
- VARRAY_POP (g->stack);
+ x = VEC_pop (int, 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)
+ while (VEC_length (tree, 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);
+ src = VEC_pop (tree, g->const_copies);
+ dest = VEC_pop (tree, 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);
- gcc_assert (y != -1);
-
- tmp = PHI_ARG_DEF (phi, y);
-#ifdef ENABLE_CHECKING
- if (!phi_ssa_name_p (tmp))
- {
- print_exprs_edge (stderr, e,
- "\nConstant argument in PHI. Can't insert :",
- var, " = ", tmp);
- internal_error ("SSA corruption");
- }
-#else
- gcc_assert (phi_ssa_name_p (tmp));
-#endif
- y = var_to_partition (map, tmp);
- gcc_assert (x != NO_PARTITION);
- gcc_assert (y != NO_PARTITION);
-#ifdef ENABLE_CHECKING
- 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)));
- internal_error ("SSA corruption");
- }
-#else
- gcc_assert (root_var_find (rv, x) == root_var_find (rv, y));
-#endif
-
- if (x != y)
- {
-#ifdef ENABLE_CHECKING
- if (conflict_graph_conflict_p (graph, x, y))
- {
- print_exprs_edge (stderr, e, "\n Conflict ",
- partition_to_var (map, x),
- " and ", partition_to_var (map, y));
- internal_error ("SSA corruption");
- }
-#else
- gcc_assert (!conflict_graph_conflict_p (graph, x, y));
-#endif
-
- /* 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);
- }
-#ifdef ENABLE_CHECKING
- 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));
- internal_error ("SSA corruption");
- }
-#else
- gcc_assert (var_union (map, var, tmp) != NO_PARTITION);
-#endif
- conflict_graph_merge_regs (graph, x, y);
- }
- }
-}
-
-
-/* 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)
- {
- /* This root variable should have not already been assigned
- to another partition which is not coalesced with this one. */
- gcc_assert (!ann->out_of_ssa_tag);
-
- 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;
+ int x, num;
+ tree var, root;
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;
+ /* It must already be coalesced. */
+ gcc_assert (ann->out_of_ssa_tag == 1);
if (dump_file && (dump_flags & TDF_DETAILS))
{
- fprintf (dump_file, "partition %d has variable ", x);
+ fprintf (dump_file, "partition %d already 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)
+ else
+ {
+ root = SSA_NAME_VAR (var);
+ ann = var_ann (root);
+ /* If ROOT is already associated, create a new one. */
+ 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;
+ root = create_temp (root);
+ ann = var_ann (root);
}
-
- 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);
-
+ /* ROOT has not been coalesced yet, so use it. */
if (dump_file && (dump_flags & TDF_DETAILS))
{
- fprintf (dump_file, " --> New temp: '");
- print_generic_expr (dump_file, var, TDF_SLIM);
- fprintf (dump_file, "'\n");
+ fprintf (dump_file, "Partition %d is assigned to var ", x);
+ print_generic_stmt (dump_file, root, TDF_SLIM);
}
+ change_partition_var (map, root, x);
}
}
-
- root_var_delete (rv);
}
int version = SSA_NAME_VERSION (var);
if (expr[version])
{
- tree new_expr = TREE_OPERAND (expr[version], 1);
+ tree new_expr = GIMPLE_STMT_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;
+ GIMPLE_STMT_OPERAND (expr[version], 1) = NULL_TREE;
return true;
}
}
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;
- }
- }
+ /* Do nothing if we are replacing this variable with an expression. */
+ if (expr && expr[SSA_NAME_VERSION (var)])
+ return true;
new_var = var_to_partition_to_var (map, var);
if (new_var)
}
}
#endif
- remove_phi_node (phi, NULL_TREE, bb);
+ remove_phi_node (phi, NULL_TREE, true);
}
}
}
}
-/* 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. */
+/* 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
-coalesce_vars (var_map map, tree_live_info_p liveinfo)
+rewrite_trees (var_map map, tree *values)
{
+ elim_graph g;
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. */
+ 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, arg;
- int p;
+ tree phi;
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++)
+ tree T0 = var_to_partition_to_var (map, PHI_RESULT (phi));
+ if (T0 == NULL_TREE)
{
- 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);
+ 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);
+ internal_error ("SSA corruption");
+ }
+ }
}
}
- }
-
-
- /* Re-calculate live on exit info. */
- calculate_live_on_exit (liveinfo);
+ }
+#endif
- if (dump_file && (dump_flags & TDF_DETAILS))
+ /* Replace PHI nodes with any required copies. */
+ g = new_elim_graph (map->num_partitions);
+ g->map = map;
+ FOR_EACH_BB (bb)
{
- fprintf (dump_file, "Live range info for variable memory coalescing.\n");
- dump_live_info (dump_file, liveinfo, LIVEDUMP_ALL);
+ for (si = bsi_start (bb); !bsi_end_p (si); )
+ {
+ tree stmt = bsi_stmt (si);
+ use_operand_p use_p, copy_use_p;
+ def_operand_p def_p;
+ bool remove = false, is_copy = false;
+ int num_uses = 0;
+ stmt_ann_t ann;
+ ssa_op_iter iter;
- fprintf (dump_file, "Coalesce list from phi nodes:\n");
- dump_coalesce_list (dump_file, cl);
- }
+ ann = stmt_ann (stmt);
+ changed = false;
+ if (TREE_CODE (stmt) == GIMPLE_MODIFY_STMT
+ && (TREE_CODE (GIMPLE_STMT_OPERAND (stmt, 1)) == SSA_NAME))
+ is_copy = true;
- 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);
+ copy_use_p = NULL_USE_OPERAND_P;
+ FOR_EACH_SSA_USE_OPERAND (use_p, stmt, iter, SSA_OP_USE)
+ {
+ if (replace_use_variable (map, use_p, values))
+ changed = true;
+ copy_use_p = use_p;
+ num_uses++;
+ }
- graph = build_tree_conflict_graph (liveinfo, tv, cl);
+ if (num_uses != 1)
+ is_copy = false;
- 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);
+ def_p = SINGLE_SSA_DEF_OPERAND (stmt, SSA_OP_DEF);
- fprintf (dump_file, "Coalesce list after conflict graph build:\n");
- dump_coalesce_list (dump_file, cl);
- }
+ if (def_p != NULL)
+ {
+ /* Mark this stmt for removal if it is the list of replaceable
+ expressions. */
+ if (values && values[SSA_NAME_VERSION (DEF_FROM_PTR (def_p))])
+ remove = true;
+ else
+ {
+ 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)
+ {
+ gcc_assert (copy_use_p != NULL_USE_OPERAND_P);
+ if (DEF_FROM_PTR (def_p) == USE_FROM_PTR (copy_use_p))
+ remove = true;
+ }
+ }
+ }
+ else
+ FOR_EACH_SSA_DEF_OPERAND (def_p, stmt, iter, SSA_OP_DEF)
+ if (replace_def_variable (map, def_p, NULL))
+ changed = true;
- 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);
- }
+ /* Remove any stmts marked for removal. */
+ if (remove)
+ bsi_remove (&si, true);
+ else
+ {
+ if (changed)
+ if (maybe_clean_or_replace_eh_stmt (stmt, stmt))
+ tree_purge_dead_eh_edges (bb);
+ bsi_next (&si);
+ }
+ }
- coalesce_tpa_members (tv, graph, map, cl,
- ((dump_flags & TDF_DETAILS) ? dump_file : NULL));
+ phi = phi_nodes (bb);
+ if (phi)
+ {
+ edge_iterator ei;
+ FOR_EACH_EDGE (e, ei, bb->preds)
+ eliminate_phi (e, g);
+ }
+ }
- type_var_delete (tv);
- delete_coalesce_list (cl);
+ delete_elim_graph (g);
}
+/* These are the local work structures used to determine the best place to
+ insert the copies that were placed on edges by the SSA->normal pass.. */
+static VEC(edge,heap) *edge_leader;
+static VEC(tree,heap) *stmt_list;
+static bitmap leader_has_match = NULL;
+static edge leader_match = NULL;
-/* 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.
+/* Pass this function to make_forwarder_block so that all the edges with
+ matching PENDING_STMT lists to 'curr_stmt_list' get redirected. E is the
+ edge to test for a match. */
- A pass is made through the function, one block at a time. No cross block
- information is tracked.
+static inline bool
+same_stmt_list_p (edge e)
+{
+ return (e->aux == (PTR) leader_match) ? true : false;
+}
- 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.
+/* Return TRUE if S1 and S2 are equivalent copies. */
- 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.
+static inline bool
+identical_copies_p (const_tree s1, const_tree s2)
+{
+#ifdef ENABLE_CHECKING
+ gcc_assert (TREE_CODE (s1) == GIMPLE_MODIFY_STMT);
+ gcc_assert (TREE_CODE (s2) == GIMPLE_MODIFY_STMT);
+ gcc_assert (DECL_P (GIMPLE_STMT_OPERAND (s1, 0)));
+ gcc_assert (DECL_P (GIMPLE_STMT_OPERAND (s2, 0)));
+#endif
- 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.
+ if (GIMPLE_STMT_OPERAND (s1, 0) != GIMPLE_STMT_OPERAND (s2, 0))
+ return false;
- Whenever a V_MAY_DEF is seen, all expressions dependent this
- VIRTUAL_PARTITION are removed from consideration.
+ s1 = GIMPLE_STMT_OPERAND (s1, 1);
+ s2 = GIMPLE_STMT_OPERAND (s2, 1);
- 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++)
- gcc_assert (!t->partition_dep_list[x]);
-#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));
+ if (s1 != s2)
+ return false;
- return p;
+ return true;
}
-/* Add value list node P to the free list in TABLE. */
+/* Compare the PENDING_STMT list for edges E1 and E2. Return true if the lists
+ contain the same sequence of copies. */
-static inline void
-free_value_expr (temp_expr_table_p table, value_expr_p p)
+static inline bool
+identical_stmt_lists_p (const_edge e1, const_edge e2)
{
- p->next = table->free_list;
- table->free_list = p;
-}
+ tree t1 = PENDING_STMT (e1);
+ tree t2 = PENDING_STMT (e2);
+ tree_stmt_iterator tsi1, tsi2;
+ gcc_assert (TREE_CODE (t1) == STATEMENT_LIST);
+ gcc_assert (TREE_CODE (t2) == STATEMENT_LIST);
-/* 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)
+ for (tsi1 = tsi_start (t1), tsi2 = tsi_start (t2);
+ !tsi_end_p (tsi1) && !tsi_end_p (tsi2);
+ tsi_next (&tsi1), tsi_next (&tsi2))
{
- if (curr->value == value)
+ if (!identical_copies_p (tsi_stmt (tsi1), tsi_stmt (tsi2)))
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 (!tsi_end_p (tsi1) || ! tsi_end_p (tsi2))
+ return false;
- if (!find_value_in_list (*list, value, NULL))
- {
- info = new_value_expr (tab);
- info->value = value;
- info->next = *list;
- *list = info;
- }
+ return true;
}
-/* 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. */
+/* Allocate data structures used in analyze_edges_for_bb. */
-static inline void
-add_info_to_list (temp_expr_table_p tab, value_expr_p *list, value_expr_p info)
+static void
+init_analyze_edges_for_bb (void)
{
- if (find_value_in_list (*list, info->value, NULL))
- free_value_expr (tab, info);
- else
- {
- info->next = *list;
- *list = info;
- }
+ edge_leader = VEC_alloc (edge, heap, 25);
+ stmt_list = VEC_alloc (tree, heap, 25);
+ leader_has_match = BITMAP_ALLOC (NULL);
}
-/* Look for VALUE in LIST. If found, remove it from the list and return it's
- pointer. */
+/* Free data structures used in analyze_edges_for_bb. */
-static value_expr_p
-remove_value_from_list (value_expr_p *list, int value)
+static void
+fini_analyze_edges_for_bb (void)
{
- 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;
+ VEC_free (edge, heap, edge_leader);
+ VEC_free (tree, heap, stmt_list);
+ BITMAP_FREE (leader_has_match);
}
-
-/* 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)
+/* A helper function to be called via walk_tree. Return DATA if it is
+ contained in subtree TP. */
+
+static tree
+contains_tree_r (tree * tp, int *walk_subtrees, void *data)
{
- int i, x;
- value_expr_p info;
-
- i = SSA_NAME_VERSION (var);
- if (bitmap_bit_p (tab->replaceable, i))
+ if (*tp == data)
{
- /* 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);
- }
+ *walk_subtrees = 0;
+ return data;
}
else
- {
- i = var_to_partition (tab->map, var);
- gcc_assert (i != NO_PARTITION);
- 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);
- }
+ return NULL_TREE;
}
+/* A threshold for the number of insns contained in the latch block.
+ It is used to prevent blowing the loop with too many copies from
+ the latch. */
+#define MAX_STMTS_IN_LATCH 2
-/* Check if expression STMT is suitable for replacement in table TAB. If so,
- create an expression entry. Return true if this stmt is replaceable. */
+/* Return TRUE if the stmts on SINGLE-EDGE can be moved to the
+ body of the loop. This should be permitted only if SINGLE-EDGE is a
+ single-basic-block latch edge and thus cleaning the latch will help
+ to create a single-basic-block loop. Otherwise return FALSE. */
static bool
-check_replaceable (temp_expr_table_p tab, tree stmt)
+process_single_block_loop_latch (edge single_edge)
{
- stmt_ann_t ann;
- vuse_optype vuseops;
- def_optype defs;
- use_optype uses;
- tree var, def;
- int num_use_ops, version;
- var_map map = tab->map;
- ssa_op_iter iter;
-
- if (TREE_CODE (stmt) != MODIFY_EXPR)
+ tree stmts;
+ basic_block b_exit, b_pheader, b_loop = single_edge->src;
+ edge_iterator ei;
+ edge e;
+ block_stmt_iterator bsi, bsi_exit;
+ tree_stmt_iterator tsi;
+ tree expr, stmt;
+ unsigned int count = 0;
+
+ if (single_edge == NULL || (single_edge->dest != single_edge->src)
+ || (EDGE_COUNT (b_loop->succs) != 2)
+ || (EDGE_COUNT (b_loop->preds) != 2))
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;
+ /* Get the stmts on the latch edge. */
+ stmts = PENDING_STMT (single_edge);
- /* Assignments to variables assigned to hard registers are not
- replaceable. */
- if (DECL_HARD_REGISTER (SSA_NAME_VAR (def)))
- return false;
+ /* Find the successor edge which is not the latch edge. */
+ FOR_EACH_EDGE (e, ei, b_loop->succs)
+ if (e->dest != b_loop)
+ break;
- /* There must be no V_MAY_DEFS. */
- if (NUM_V_MAY_DEFS (V_MAY_DEF_OPS (ann)) != 0)
- return false;
+ b_exit = e->dest;
- /* There must be no V_MUST_DEFS. */
- if (NUM_V_MUST_DEFS (V_MUST_DEF_OPS (ann)) != 0)
+ /* Check that the exit block has only the loop as a predecessor,
+ and that there are no pending stmts on that edge as well. */
+ if (EDGE_COUNT (b_exit->preds) != 1 || PENDING_STMT (e))
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))))
+ /* Find the predecessor edge which is not the latch edge. */
+ FOR_EACH_EDGE (e, ei, b_loop->preds)
+ if (e->src != b_loop)
+ break;
+
+ b_pheader = e->src;
+
+ if (b_exit == b_pheader || b_exit == b_loop || b_pheader == b_loop)
return false;
- uses = USE_OPS (ann);
- num_use_ops = NUM_USES (uses);
- vuseops = VUSE_OPS (ann);
+ bsi_exit = bsi_after_labels (b_exit);
- /* 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. */
+ /* Get the last stmt in the loop body. */
+ bsi = bsi_last (single_edge->src);
+ stmt = bsi_stmt (bsi);
- if (num_use_ops == 0 && NUM_VUSES (vuseops) == 0)
+ if (TREE_CODE (stmt) != COND_EXPR)
return false;
- version = SSA_NAME_VERSION (def);
-
- /* Add this expression to the dependency list for each use partition. */
- FOR_EACH_SSA_TREE_OPERAND (var, stmt, iter, SSA_OP_USE)
+ expr = COND_EXPR_COND (stmt);
+ /* Iterate over the insns on the latch and count them. */
+ for (tsi = tsi_start (stmts); !tsi_end_p (tsi); tsi_next (&tsi))
{
- add_dependance (tab, version, var);
+ tree stmt1 = tsi_stmt (tsi);
+ tree var;
+
+ count++;
+ /* Check that the condition does not contain any new definition
+ created in the latch as the stmts from the latch intended
+ to precede it. */
+ if (TREE_CODE (stmt1) != GIMPLE_MODIFY_STMT)
+ return false;
+ var = GIMPLE_STMT_OPERAND (stmt1, 0);
+ if (TREE_THIS_VOLATILE (var)
+ || TYPE_VOLATILE (TREE_TYPE (var))
+ || walk_tree (&expr, contains_tree_r, var, NULL))
+ return false;
}
+ /* Check that the latch does not contain more than MAX_STMTS_IN_LATCH
+ insns. The purpose of this restriction is to prevent blowing the
+ loop with too many copies from the latch. */
+ if (count > MAX_STMTS_IN_LATCH)
+ return false;
- /* If there are VUSES, add a dependence on virtual defs. */
- if (NUM_VUSES (vuseops) != 0)
+ /* Apply the transformation - clean up the latch block:
+
+ var = something;
+ L1:
+ x1 = expr;
+ if (cond) goto L2 else goto L3;
+ L2:
+ var = x1;
+ goto L1
+ L3:
+ ...
+
+ ==>
+
+ var = something;
+ L1:
+ x1 = expr;
+ tmp_var = var;
+ var = x1;
+ if (cond) goto L1 else goto L2;
+ L2:
+ var = tmp_var;
+ ...
+ */
+ for (tsi = tsi_start (stmts); !tsi_end_p (tsi); tsi_next (&tsi))
{
- 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));
+ tree stmt1 = tsi_stmt (tsi);
+ tree var, tmp_var, copy;
+
+ /* Create a new variable to load back the value of var in case
+ we exit the loop. */
+ var = GIMPLE_STMT_OPERAND (stmt1, 0);
+ tmp_var = create_temp (var);
+ copy = build2 (GIMPLE_MODIFY_STMT, TREE_TYPE (tmp_var), tmp_var, var);
+ set_is_used (tmp_var);
+ bsi_insert_before (&bsi, copy, BSI_SAME_STMT);
+ copy = build2 (GIMPLE_MODIFY_STMT, TREE_TYPE (tmp_var), var, tmp_var);
+ bsi_insert_before (&bsi_exit, copy, BSI_SAME_STMT);
}
+ PENDING_STMT (single_edge) = 0;
+ /* Insert the new stmts to the loop body. */
+ bsi_insert_before (&bsi, stmts, BSI_NEW_STMT);
+
+ if (dump_file)
+ fprintf (dump_file,
+ "\nCleaned-up latch block of loop with single BB: %d\n\n",
+ single_edge->dest->index);
+
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. */
+/* Look at all the incoming edges to block BB, and decide where the best place
+ to insert the stmts on each edge are, and perform those insertions. */
static void
-finish_expr (temp_expr_table_p tab, int version, bool replace)
+analyze_edges_for_bb (basic_block bb)
{
- value_expr_p info, tmp;
- int partition;
+ edge e;
+ edge_iterator ei;
+ int count;
+ unsigned int x;
+ bool have_opportunity;
+ block_stmt_iterator bsi;
+ tree stmt;
+ edge single_edge = NULL;
+ bool is_label;
+ edge leader;
+
+ count = 0;
+
+ /* Blocks which contain at least one abnormal edge cannot use
+ make_forwarder_block. Look for these blocks, and commit any PENDING_STMTs
+ found on edges in these block. */
+ have_opportunity = true;
+ FOR_EACH_EDGE (e, ei, bb->preds)
+ if (e->flags & EDGE_ABNORMAL)
+ {
+ have_opportunity = false;
+ break;
+ }
- /* 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)
+ if (!have_opportunity)
{
- partition = info->value;
- gcc_assert (tab->partition_dep_list[partition]);
- tmp = remove_value_from_list (&(tab->partition_dep_list[partition]),
- version);
- gcc_assert (tmp);
- 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);
+ FOR_EACH_EDGE (e, ei, bb->preds)
+ if (PENDING_STMT (e))
+ bsi_commit_one_edge_insert (e, NULL);
+ return;
}
- if (replace)
+ /* Find out how many edges there are with interesting pending stmts on them.
+ Commit the stmts on edges we are not interested in. */
+ FOR_EACH_EDGE (e, ei, bb->preds)
{
- tab->saw_replaceable = true;
- bitmap_set_bit (tab->replaceable, version);
- }
- else
- {
- gcc_assert (!bitmap_bit_p (tab->replaceable, version));
- tab->version_info[version] = NULL;
+ if (PENDING_STMT (e))
+ {
+ gcc_assert (!(e->flags & EDGE_ABNORMAL));
+ if (e->flags & EDGE_FALLTHRU)
+ {
+ bsi = bsi_start (e->src);
+ if (!bsi_end_p (bsi))
+ {
+ stmt = bsi_stmt (bsi);
+ bsi_next (&bsi);
+ gcc_assert (stmt != NULL_TREE);
+ is_label = (TREE_CODE (stmt) == LABEL_EXPR);
+ /* Punt if it has non-label stmts, or isn't local. */
+ if (!is_label || DECL_NONLOCAL (TREE_OPERAND (stmt, 0))
+ || !bsi_end_p (bsi))
+ {
+ bsi_commit_one_edge_insert (e, NULL);
+ continue;
+ }
+ }
+ }
+ single_edge = e;
+ count++;
+ }
}
-}
-
-
-/* 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])
+ /* If there aren't at least 2 edges, no sharing will happen. */
+ if (count < 2)
{
- 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];
+ if (single_edge)
+ {
+ /* Add stmts to the edge unless processed specially as a
+ single-block loop latch edge. */
+ if (!process_single_block_loop_latch (single_edge))
+ bsi_commit_one_edge_insert (single_edge, NULL);
+ }
+ return;
}
- 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. */
+ /* Ensure that we have empty worklists. */
+#ifdef ENABLE_CHECKING
+ gcc_assert (VEC_length (edge, edge_leader) == 0);
+ gcc_assert (VEC_length (tree, stmt_list) == 0);
+ gcc_assert (bitmap_empty_p (leader_has_match));
+#endif
-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;
- var_map map = tab->map;
- value_expr_p p;
- ssa_op_iter iter;
-
- for (bsi = bsi_start (bb); !bsi_end_p (bsi); bsi_next (&bsi))
+ /* Find the "leader" block for each set of unique stmt lists. Preference is
+ given to FALLTHRU blocks since they would need a GOTO to arrive at another
+ block. The leader edge destination is the block which all the other edges
+ with the same stmt list will be redirected to. */
+ have_opportunity = false;
+ FOR_EACH_EDGE (e, ei, bb->preds)
{
- stmt = bsi_stmt (bsi);
- ann = stmt_ann (stmt);
-
- /* Determine if this stmt finishes an existing expression. */
- FOR_EACH_SSA_TREE_OPERAND (def, stmt, iter, SSA_OP_USE)
+ if (PENDING_STMT (e))
{
- if (tab->version_info[SSA_NAME_VERSION (def)])
+ bool found = false;
+
+ /* Look for the same stmt list in edge leaders list. */
+ for (x = 0; VEC_iterate (edge, edge_leader, x, leader); x++)
{
- /* 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);
+ if (identical_stmt_lists_p (leader, e))
+ {
+ /* Give this edge the same stmt list pointer. */
+ PENDING_STMT (e) = NULL;
+ e->aux = leader;
+ bitmap_set_bit (leader_has_match, x);
+ have_opportunity = found = true;
+ break;
+ }
}
- }
-
- /* Next, see if this stmt kills off an active expression. */
- FOR_EACH_SSA_TREE_OPERAND (def, stmt, iter, SSA_OP_DEF)
- {
- 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);
+ /* If no similar stmt list, add this edge to the leader list. */
+ if (!found)
+ {
+ VEC_safe_push (edge, heap, edge_leader, e);
+ VEC_safe_push (tree, heap, stmt_list, PENDING_STMT (e));
+ }
}
+ }
- /* 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)
+ /* If there are no similar lists, just issue the stmts. */
+ if (!have_opportunity)
{
- find_replaceable_in_bb (table, bb);
- EXECUTE_IF_SET_IN_BITMAP ((table->partition_in_use), 0, i,
- {
- kill_expr (table, i, false);
- });
+ for (x = 0; VEC_iterate (edge, edge_leader, x, leader); x++)
+ bsi_commit_one_edge_insert (leader, NULL);
+ VEC_truncate (edge, edge_leader, 0);
+ VEC_truncate (tree, stmt_list, 0);
+ bitmap_clear (leader_has_match);
+ return;
}
- ret = free_temp_expr_table (table);
- return ret;
-}
+ if (dump_file)
+ fprintf (dump_file, "\nOpportunities in BB %d for stmt/block reduction:\n",
+ bb->index);
+
+ /* For each common list, create a forwarding block and issue the stmt's
+ in that block. */
+ for (x = 0; VEC_iterate (edge, edge_leader, x, leader); x++)
+ if (bitmap_bit_p (leader_has_match, x))
+ {
+ edge new_edge;
+ block_stmt_iterator bsi;
+ tree curr_stmt_list;
+
+ leader_match = leader;
+
+ /* The tree_* cfg manipulation routines use the PENDING_EDGE field
+ for various PHI manipulations, so it gets cleared when calls are
+ made to make_forwarder_block(). So make sure the edge is clear,
+ and use the saved stmt list. */
+ PENDING_STMT (leader) = NULL;
+ leader->aux = leader;
+ curr_stmt_list = VEC_index (tree, stmt_list, x);
+
+ new_edge = make_forwarder_block (leader->dest, same_stmt_list_p,
+ NULL);
+ bb = new_edge->dest;
+ if (dump_file)
+ {
+ fprintf (dump_file, "Splitting BB %d for Common stmt list. ",
+ leader->dest->index);
+ fprintf (dump_file, "Original block is now BB%d.\n", bb->index);
+ print_generic_stmt (dump_file, curr_stmt_list, TDF_VOPS);
+ }
+ FOR_EACH_EDGE (e, ei, new_edge->src->preds)
+ {
+ e->aux = NULL;
+ if (dump_file)
+ fprintf (dump_file, " Edge (%d->%d) lands here.\n",
+ e->src->index, e->dest->index);
+ }
-/* Dump TER expression table EXPR to file F. */
+ bsi = bsi_last (leader->dest);
+ bsi_insert_after (&bsi, curr_stmt_list, BSI_NEW_STMT);
-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])
+ leader_match = NULL;
+ /* We should never get a new block now. */
+ }
+ else
{
- 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");
+ PENDING_STMT (leader) = VEC_index (tree, stmt_list, x);
+ bsi_commit_one_edge_insert (leader, NULL);
}
- 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;
+
+ /* Clear the working data structures. */
+ VEC_truncate (edge, edge_leader, 0);
+ VEC_truncate (tree, stmt_list, 0);
+ bitmap_clear (leader_has_match);
}
-/* 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. */
+/* This function will analyze the insertions which were performed on edges,
+ and decide whether they should be left on that edge, or whether it is more
+ efficient to emit some subset of them in a single block. All stmts are
+ inserted somewhere. */
static void
-discover_nonconstant_array_refs (void)
+perform_edge_inserts (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);
- }
-}
+ if (dump_file)
+ fprintf(dump_file, "Analyzing Edge Insertions.\n");
+ /* analyze_edges_for_bb calls make_forwarder_block, which tries to
+ incrementally update the dominator information. Since we don't
+ need dominator information after this pass, go ahead and free the
+ dominator information. */
+ free_dominance_info (CDI_DOMINATORS);
+ free_dominance_info (CDI_POST_DOMINATORS);
-/* 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. */
+ /* Allocate data structures used in analyze_edges_for_bb. */
+ init_analyze_edges_for_bb ();
-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;
+ analyze_edges_for_bb (bb);
- 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;
+ analyze_edges_for_bb (EXIT_BLOCK_PTR);
- for (i = 0; i < PHI_NUM_ARGS (phi); i++)
- {
- tree arg = PHI_ARG_DEF (phi, i);
+ /* Free data structures used in analyze_edges_for_bb. */
+ fini_analyze_edges_for_bb ();
- 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);
- internal_error ("SSA corruption");
- }
- }
- }
- }
- }
+#ifdef ENABLE_CHECKING
+ {
+ edge_iterator ei;
+ edge e;
+ FOR_EACH_BB (bb)
+ {
+ FOR_EACH_EDGE (e, ei, bb->preds)
+ {
+ if (PENDING_STMT (e))
+ error (" Pending stmts not issued on PRED edge (%d, %d)\n",
+ e->src->index, e->dest->index);
+ }
+ FOR_EACH_EDGE (e, ei, bb->succs)
+ {
+ if (PENDING_STMT (e))
+ error (" Pending stmts not issued on SUCC edge (%d, %d)\n",
+ e->src->index, e->dest->index);
+ }
+ }
+ FOR_EACH_EDGE (e, ei, ENTRY_BLOCK_PTR->succs)
+ {
+ if (PENDING_STMT (e))
+ error (" Pending stmts not issued on ENTRY edge (%d, %d)\n",
+ e->src->index, e->dest->index);
+ }
+ FOR_EACH_EDGE (e, ei, EXIT_BLOCK_PTR->preds)
+ {
+ if (PENDING_STMT (e))
+ error (" Pending stmts not issued on EXIT edge (%d, %d)\n",
+ e->src->index, e->dest->index);
+ }
+ }
#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 num_uses, num_defs;
- use_optype uses;
- def_optype defs;
- tree stmt = bsi_stmt (si);
- use_operand_p use_p;
- def_operand_p def_p;
- int remove = 0, is_copy = 0;
- stmt_ann_t ann;
- ssa_op_iter iter;
-
- 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_EACH_SSA_USE_OPERAND (use_p, stmt, iter, SSA_OP_USE)
- {
- 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_EACH_SSA_DEF_OPERAND (def_p, stmt, iter, SSA_OP_DEF)
- {
- 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 & !remove)
- 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. */
+/* Remove the ssa-names in the current function and translate them into normal
+ compiler variables. PERFORM_TER is true if Temporary Expression Replacement
+ should also be used. */
static void
-remove_ssa_form (FILE *dump, var_map map, int flags)
+remove_ssa_form (bool perform_ter)
{
- tree_live_info_p liveinfo;
basic_block bb;
tree phi, next;
- FILE *save;
tree *values = NULL;
+ var_map map;
- 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);
+ map = coalesce_ssa_name ();
- /* Make sure even single occurrence variables are in the list now. */
- if ((flags & SSANORM_COMBINE_TEMPS) == 0)
- compact_var_map (map, VARMAP_NORMAL);
+ /* Return to viewing the variable list as just all reference variables after
+ coalescing has been performed. */
+ partition_view_normal (map, false);
if (dump_file && (dump_flags & TDF_DETAILS))
{
dump_var_map (dump_file, map);
}
- if (flags & SSANORM_PERFORM_TER)
+ if (perform_ter)
{
values = find_replaceable_exprs (map);
if (values && dump_file && (dump_flags & TDF_DETAILS))
if (dump_file && (dump_flags & TDF_DETAILS))
{
- fprintf (dump_file, "After Root variable replacement:\n");
+ fprintf (dump_file, "After Base 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. */
+ /* 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);
+ remove_phi_node (phi, NULL_TREE, true);
}
}
- dump_file = save;
+ /* If any copies were inserted on edges, analyze and insert them now. */
+ perform_edge_inserts ();
+
+ 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. */
+
+/* Search every PHI node for arguments associated with backedges which
+ we can trivially determine will need a copy (the argument is either
+ not an SSA_NAME or the argument has a different underlying variable
+ than the PHI result).
+
+ Insert a copy from the PHI argument to a new destination at the
+ end of the block with the backedge to the top of the loop. Update
+ the PHI argument to reference this new destination. */
static void
-rewrite_out_of_ssa (void)
+insert_backedge_copies (void)
{
- var_map map;
- int var_flags = 0;
- int ssa_flags = (SSANORM_REMOVE_ALL_PHIS | SSANORM_USE_COALESCE_LIST);
+ basic_block bb;
- if (!flag_tree_live_range_split)
- ssa_flags |= SSANORM_COALESCE_PARTITIONS;
-
- eliminate_virtual_phis ();
+ FOR_EACH_BB (bb)
+ {
+ tree phi;
- if (dump_file && (dump_flags & TDF_DETAILS))
- dump_tree_cfg (dump_file, dump_flags & ~TDF_DETAILS);
+ for (phi = phi_nodes (bb); phi; phi = PHI_CHAIN (phi))
+ {
+ tree result = PHI_RESULT (phi);
+ tree result_var;
+ int i;
- /* 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;
+ if (!is_gimple_reg (result))
+ continue;
- map = create_ssa_var_map (var_flags);
+ result_var = SSA_NAME_VAR (result);
+ for (i = 0; i < PHI_NUM_ARGS (phi); i++)
+ {
+ tree arg = PHI_ARG_DEF (phi, i);
+ edge e = PHI_ARG_EDGE (phi, i);
+
+ /* If the argument is not an SSA_NAME, then we will need a
+ constant initialization. If the argument is an SSA_NAME with
+ a different underlying variable then a copy statement will be
+ needed. */
+ if ((e->flags & EDGE_DFS_BACK)
+ && (TREE_CODE (arg) != SSA_NAME
+ || SSA_NAME_VAR (arg) != result_var))
+ {
+ tree stmt, name, last = NULL;
+ block_stmt_iterator bsi;
+
+ bsi = bsi_last (PHI_ARG_EDGE (phi, i)->src);
+ if (!bsi_end_p (bsi))
+ last = bsi_stmt (bsi);
+
+ /* In theory the only way we ought to get back to the
+ start of a loop should be with a COND_EXPR or GOTO_EXPR.
+ However, better safe than sorry.
+ If the block ends with a control statement or
+ something that might throw, then we have to
+ insert this assignment before the last
+ statement. Else insert it after the last statement. */
+ if (last && stmt_ends_bb_p (last))
+ {
+ /* If the last statement in the block is the definition
+ site of the PHI argument, then we can't insert
+ anything after it. */
+ if (TREE_CODE (arg) == SSA_NAME
+ && SSA_NAME_DEF_STMT (arg) == last)
+ continue;
+ }
- if (flag_tree_combine_temps)
- ssa_flags |= SSANORM_COMBINE_TEMPS;
- if (flag_tree_ter && !flag_mudflap)
- ssa_flags |= SSANORM_PERFORM_TER;
+ /* Create a new instance of the underlying variable of the
+ PHI result. */
+ stmt = build_gimple_modify_stmt (NULL_TREE,
+ PHI_ARG_DEF (phi, i));
+ name = make_ssa_name (result_var, stmt);
+ GIMPLE_STMT_OPERAND (stmt, 0) = name;
+
+ /* Insert the new statement into the block and update
+ the PHI node. */
+ if (last && stmt_ends_bb_p (last))
+ bsi_insert_before (&bsi, stmt, BSI_NEW_STMT);
+ else
+ bsi_insert_after (&bsi, stmt, BSI_NEW_STMT);
+ SET_PHI_ARG_DEF (phi, i, name);
+ }
+ }
+ }
+ }
+}
- remove_ssa_form (dump_file, map, ssa_flags);
+/* Take the current function out of SSA form, translating PHIs as described in
+ R. Morgan, ``Building an Optimizing Compiler'',
+ Butterworth-Heinemann, Boston, MA, 1998. pp 176-186. */
+
+static unsigned int
+rewrite_out_of_ssa (void)
+{
+ /* If elimination of a PHI requires inserting a copy on a backedge,
+ then we will have to split the backedge which has numerous
+ undesirable performance effects.
+
+ A significant number of such cases can be handled here by inserting
+ copies into the loop itself. */
+ insert_backedge_copies ();
+
+ eliminate_virtual_phis ();
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 ();
+ remove_ssa_form (flag_tree_ter && !flag_mudflap);
- /* Flush out flow graph and SSA data. */
- delete_var_map (map);
+ if (dump_file && (dump_flags & TDF_DETAILS))
+ dump_tree_cfg (dump_file, dump_flags & ~TDF_DETAILS);
- /* Mark arrays indexed with non-constant indices with TREE_ADDRESSABLE. */
- discover_nonconstant_array_refs ();
+ cfun->gimple_df->in_ssa_p = false;
+ return 0;
}
/* Define the parameters of the out of SSA pass. */
-struct tree_opt_pass pass_del_ssa =
+struct gimple_opt_pass pass_del_ssa =
{
+ {
+ GIMPLE_PASS,
"optimized", /* name */
NULL, /* gate */
rewrite_out_of_ssa, /* execute */
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 */
- 0 /* letter */
+ TODO_dump_func
+ | TODO_ggc_collect
+ | TODO_remove_unused_locals /* todo_flags_finish */
+ }
};
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