/* Convert a program in SSA form into Normal form.
- Copyright (C) 2004 Free Software Foundation, Inc.
+ Copyright (C) 2004, 2005 Free Software Foundation, Inc.
Contributed by Andrew Macleod <amacleod@redhat.com>
This file is part of GCC.
#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"
#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
+#define SSANORM_COALESCE_PARTITIONS 0x4
/* 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
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 eliminate_build (elim_graph, basic_block);
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 void eliminate_phi (edge, 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 *);
if (TREE_CODE (t) == SSA_NAME)
t = SSA_NAME_VAR (t);
-
- if (TREE_CODE (t) != VAR_DECL
- && TREE_CODE (t) != PARM_DECL)
- abort ();
+
+ gcc_assert (TREE_CODE (t) == VAR_DECL || TREE_CODE (t) == PARM_DECL);
type = TREE_TYPE (t);
tmp = DECL_NAME (t);
if (name == NULL)
name = "temp";
tmp = create_tmp_var (type, name);
+
+ if (DECL_DEBUG_EXPR (t) && DECL_DEBUG_EXPR_IS_FROM (t))
+ {
+ DECL_DEBUG_EXPR (tmp) = DECL_DEBUG_EXPR (t);
+ DECL_DEBUG_EXPR_IS_FROM (tmp) = 1;
+ }
+ else if (!DECL_IGNORED_P (t))
+ {
+ DECL_DEBUG_EXPR (tmp) = t;
+ DECL_DEBUG_EXPR_IS_FROM (tmp) = 1;
+ }
DECL_ARTIFICIAL (tmp) = DECL_ARTIFICIAL (t);
+ DECL_IGNORED_P (tmp) = DECL_IGNORED_P (t);
add_referenced_tmp_var (tmp);
/* add_referenced_tmp_var will create the annotation and set up some
}
-/* 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);
- if (pi == -1)
- abort();
- 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
}
-/* 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;
-#if defined ENABLE_CHECKING
- if (i == -1)
- abort ();
- if (VARRAY_ACTIVE_SIZE (g->const_copies) != 0)
- abort ();
-#endif
+ gcc_assert (VARRAY_ACTIVE_SIZE (g->const_copies) == 0);
/* 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);
+ eliminate_build (g, B);
if (elim_graph_size (g) != 0)
{
basic_block bb;
edge e;
tree phi, var, tmp;
- int x, y;
+ int x, y, z;
+ edge_iterator ei;
/* 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)
+ FOR_EACH_EDGE (e, ei, bb->succs)
if (e->dest != EXIT_BLOCK_PTR && e->flags & EDGE_ABNORMAL)
for (phi = phi_nodes (e->dest); phi; phi = PHI_CHAIN (phi))
{
if (x == NO_PARTITION)
continue;
- y = phi_arg_from_edge (phi, e);
- if (y == -1)
- abort ();
-
- tmp = PHI_ARG_DEF (phi, y);
+ tmp = PHI_ARG_DEF (phi, e->dest_idx);
+#ifdef ENABLE_CHECKING
if (!phi_ssa_name_p (tmp))
{
print_exprs_edge (stderr, e,
"\nConstant argument in PHI. Can't insert :",
var, " = ", tmp);
- abort ();
+ internal_error ("SSA corruption");
}
+#else
+ gcc_assert (phi_ssa_name_p (tmp));
+#endif
y = var_to_partition (map, tmp);
- if (x == NO_PARTITION || y == NO_PARTITION)
- abort ();
+ 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)));
- abort ();
+ internal_error ("SSA corruption");
}
+#else
+ gcc_assert (root_var_find (rv, x) == root_var_find (rv, y));
+#endif
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
+#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));
- abort ();
+ 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);
}
+ z = var_union (map, var, tmp);
+#ifdef ENABLE_CHECKING
+ if (z == 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 (z != NO_PARTITION);
+#endif
+ gcc_assert (z == x || z == y);
+ if (z == x)
+ conflict_graph_merge_regs (graph, x, y);
+ else
+ conflict_graph_merge_regs (graph, y, x);
}
}
}
static tree_live_info_p
coalesce_ssa_name (var_map map, int flags)
{
- int num, x, i;
+ unsigned num, x, i;
sbitmap live;
tree var, phi;
root_var_p rv;
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)
{
- 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))
{
- 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 < (unsigned)PHI_NUM_ARGS (phi); x++)
{
- tree res = PHI_RESULT (phi);
- int p = var_to_partition (map, res);
- if (p == NO_PARTITION)
+ tree arg = PHI_ARG_DEF (phi, x);
+ int p2;
+
+ if (TREE_CODE (arg) != SSA_NAME)
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);
- }
+ 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++)
+ /* 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)
{
- tree p = partition_to_var (map, x);
- if (TREE_CODE (SSA_NAME_VAR(p)) == RESULT_DECL)
+ if (var == NULL_TREE)
{
- if (var == NULL_TREE)
- {
- var = p;
- i = x;
- }
- else
- add_coalesce (cl, i, x, 1);
+ var = p;
+ i = x;
}
+ else
+ add_coalesce (cl, i, x, 1);
}
}
/* 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 ();
- }
+ /* 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))
{
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));
+ 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));
+ coalesce_tpa_members (rv, graph, map, NULL,
+ ((dump_flags & TDF_DETAILS) ? dump_file
+ : NULL));
if (cl)
delete_coalesce_list (cl);
root_var_delete (rv);
print_generic_expr (stderr, arg, TDF_SLIM);
fprintf (stderr, "), but the result is :");
print_generic_stmt (stderr, phi, TDF_SLIM);
- abort();
+ internal_error ("SSA corruption");
}
}
#endif
- remove_phi_node (phi, NULL_TREE, bb);
+ remove_phi_node (phi, NULL_TREE);
}
}
}
basic_block bb;
type_var_p tv;
tree var;
- int x, p, p2;
+ unsigned x, p, p2;
coalesce_list_p cl;
conflict_graph graph;
FOR_EACH_BB (bb)
{
tree phi, arg;
- int p;
+ unsigned 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)
+ if (p == (unsigned)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++)
+ for (x = 0; x < (unsigned)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)
+ if (p2 == (unsigned)NO_PARTITION)
continue;
if (p != p2)
add_coalesce (cl, p, p2, 1);
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->replaceable = BITMAP_ALLOC (NULL);
+ t->partition_in_use = BITMAP_ALLOC (NULL);
t->saw_replaceable = false;
t->virtual_partition = num_var_partitions (map);
tree *ret = NULL;
#ifdef ENABLE_CHECKING
- int x;
+ unsigned x;
for (x = 0; x <= num_var_partitions (t->map); x++)
- if (t->partition_dep_list[x] != NULL)
- abort();
+ gcc_assert (!t->partition_dep_list[x]);
#endif
while ((p = t->free_list))
free (p);
}
- BITMAP_XFREE (t->partition_in_use);
- BITMAP_XFREE (t->replaceable);
+ BITMAP_FREE (t->partition_in_use);
+ BITMAP_FREE (t->replaceable);
free (t->partition_dep_list);
if (t->saw_replaceable)
}
-/* Find VALUE if its in LIST. Return a pointer to the list object if found,
+/* Find VALUE if it's 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. */
else
{
i = var_to_partition (tab->map, var);
-#ifdef ENABLE_CHECKING
- if (i== NO_PARTITION)
- abort ();
-#endif
+ 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);
def_optype defs;
use_optype uses;
tree var, def;
- int num_use_ops, version, i;
+ int num_use_ops, version;
var_map map = tab->map;
+ ssa_op_iter iter;
+ tree call_expr;
if (TREE_CODE (stmt) != MODIFY_EXPR)
return false;
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;
if (flag_float_store && FLOAT_TYPE_P (TREE_TYPE (TREE_OPERAND (stmt, 1))))
return false;
+ /* Calls to functions with side-effects cannot be replaced. */
+ if ((call_expr = get_call_expr_in (stmt)) != NULL_TREE)
+ {
+ int call_flags = call_expr_flags (call_expr);
+ if (TREE_SIDE_EFFECTS (call_expr)
+ && !(call_flags & (ECF_PURE | ECF_CONST | ECF_NORETURN)))
+ return false;
+ }
+
uses = USE_OPS (ann);
num_use_ops = NUM_USES (uses);
vuseops = VUSE_OPS (ann);
version = SSA_NAME_VERSION (def);
/* Add this expression to the dependency list for each use partition. */
- for (i = 0; i < num_use_ops; i++)
+ FOR_EACH_SSA_TREE_OPERAND (var, stmt, iter, SSA_OP_USE)
{
- var = USE_OP (uses, i);
add_dependance (tab, version, var);
}
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
+ gcc_assert (tab->partition_dep_list[partition]);
tmp = remove_value_from_list (&(tab->partition_dep_list[partition]),
version);
-#ifdef ENABLE_CHECKING
- if (!tmp)
- abort ();
-#endif
+ 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. */
}
else
{
-#ifdef ENABLE_CHECKING
- if (bitmap_bit_p (tab->replaceable, version))
- abort ();
-#endif
+ gcc_assert (!bitmap_bit_p (tab->replaceable, version));
tab->version_info[version] = NULL;
}
}
block_stmt_iterator bsi;
tree stmt, def;
stmt_ann_t ann;
- int partition, num, i;
- use_optype uses;
- def_optype defs;
+ 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))
{
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++)
+ FOR_EACH_SSA_TREE_OPERAND (def, stmt, iter, SSA_OP_USE)
{
- 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)
+ bool same_root_var = false;
+ tree def2;
+ ssa_op_iter iter2;
+
+ /* See if the root variables are the same. If they are, we
+ do not want to do the replacement to avoid problems with
+ code size, see PR tree-optimization/17549. */
+ FOR_EACH_SSA_TREE_OPERAND (def2, stmt, iter2, SSA_OP_DEF)
+ if (SSA_NAME_VAR (def) == SSA_NAME_VAR (def2))
+ {
+ same_root_var = true;
+ break;
+ }
+
+ /* Mark expression as replaceable unless stmt is volatile
+ or DEF sets the same root variable as STMT. */
+ if (!ann->has_volatile_ops && !same_root_var)
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++)
+ FOR_EACH_SSA_TREE_OPERAND (def, stmt, iter, SSA_OP_DEF)
{
- 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);
find_replaceable_exprs (var_map map)
{
basic_block bb;
- int i;
+ unsigned i;
temp_expr_table_p table;
tree *ret;
table = new_temp_expr_table (map);
FOR_EACH_BB (bb)
{
+ bitmap_iterator bi;
+
find_replaceable_in_bb (table, bb);
- EXECUTE_IF_SET_IN_BITMAP ((table->partition_in_use), 0, i,
+ EXECUTE_IF_SET_IN_BITMAP ((table->partition_in_use), 0, i, bi)
{
kill_expr (table, i, false);
- });
+ }
}
ret = free_temp_expr_table (table);
{
tree t = *tp;
- if (TYPE_P (t) || DECL_P (t))
+ if (IS_TYPE_OR_DECL_P (t))
*walk_subtrees = 0;
else if (TREE_CODE (t) == ARRAY_REF || TREE_CODE (t) == ARRAY_RANGE_REF)
{
print_generic_expr (stderr, arg, TDF_SLIM);
fprintf (stderr, "), but the result is not :");
print_generic_stmt (stderr, phi, TDF_SLIM);
- abort();
+ internal_error ("SSA corruption");
}
}
}
{
for (si = bsi_start (bb); !bsi_end_p (si); )
{
- size_t i, num_uses, num_defs;
+ 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);
uses = USE_OPS (ann);
num_uses = NUM_USES (uses);
-
- for (i = 0; i < num_uses; i++)
+ FOR_EACH_SSA_USE_OPERAND (use_p, stmt, iter, SSA_OP_USE)
{
- use_p = USE_OP_PTR (uses, i);
if (replace_use_variable (map, use_p, values))
changed = true;
}
}
if (!remove)
{
- for (i = 0; i < num_defs; i++)
+ FOR_EACH_SSA_DEF_OPERAND (def_p, stmt, iter, SSA_OP_DEF)
{
- def_operand_p def_p = DEF_OP_PTR (defs, i);
-
if (replace_def_variable (map, def_p, NULL))
changed = true;
&& (DEF_FROM_PTR (def_p) == USE_OP (uses, 0)))
remove = 1;
}
- if (changed & !remove)
- modify_stmt (stmt);
}
/* Remove any stmts marked for removal. */
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);
+ edge_iterator ei;
+ FOR_EACH_EDGE (e, ei, bb->preds)
+ eliminate_phi (e, g);
}
}
delete_elim_graph (g);
+}
- /* If any copies were inserted on edges, actually insert them now. */
- bsi_commit_edge_inserts (NULL);
+
+/* 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 varray_type edge_leader = NULL;
+static varray_type GTY(()) stmt_list = NULL;
+static bitmap leader_has_match = NULL;
+static edge leader_match = NULL;
+
+
+/* Pass this function to make_forwarder_block so that all the edges with
+ matching PENDING_STMT lists to 'curr_stmt_list' get redirected. */
+static bool
+same_stmt_list_p (edge e)
+{
+ return (e->aux == (PTR) leader_match) ? true : false;
+}
+
+
+/* Return TRUE if S1 and S2 are equivalent copies. */
+static inline bool
+identical_copies_p (tree s1, tree s2)
+{
+#ifdef ENABLE_CHECKING
+ gcc_assert (TREE_CODE (s1) == MODIFY_EXPR);
+ gcc_assert (TREE_CODE (s2) == MODIFY_EXPR);
+ gcc_assert (DECL_P (TREE_OPERAND (s1, 0)));
+ gcc_assert (DECL_P (TREE_OPERAND (s2, 0)));
+#endif
+
+ if (TREE_OPERAND (s1, 0) != TREE_OPERAND (s2, 0))
+ return false;
+
+ s1 = TREE_OPERAND (s1, 1);
+ s2 = TREE_OPERAND (s2, 1);
+
+ if (s1 != s2)
+ return false;
+
+ return true;
+}
+
+
+/* Compare the PENDING_STMT list for two edges, and return true if the lists
+ contain the same sequence of copies. */
+
+static inline bool
+identical_stmt_lists_p (edge e1, edge e2)
+{
+ 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);
+
+ for (tsi1 = tsi_start (t1), tsi2 = tsi_start (t2);
+ !tsi_end_p (tsi1) && !tsi_end_p (tsi2);
+ tsi_next (&tsi1), tsi_next (&tsi2))
+ {
+ if (!identical_copies_p (tsi_stmt (tsi1), tsi_stmt (tsi2)))
+ break;
+ }
+
+ if (!tsi_end_p (tsi1) || ! tsi_end_p (tsi2))
+ return false;
+
+ return true;
+}
+
+
+/* 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. Output
+ any debug information to DEBUG_FILE. */
+
+static void
+analyze_edges_for_bb (basic_block bb, FILE *debug_file)
+{
+ 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;
+
+ 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;
+ }
+
+ if (!have_opportunity)
+ {
+ FOR_EACH_EDGE (e, ei, bb->preds)
+ if (PENDING_STMT (e))
+ bsi_commit_one_edge_insert (e, NULL);
+ return;
+ }
+ /* 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)
+ {
+ 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++;
+ }
+ }
+
+ /* If there aren't at least 2 edges, no sharing will happen. */
+ if (count < 2)
+ {
+ if (single_edge)
+ bsi_commit_one_edge_insert (single_edge, NULL);
+ return;
+ }
+
+ /* Ensure that we have empty worklists. */
+ if (edge_leader == NULL)
+ {
+ VARRAY_EDGE_INIT (edge_leader, 25, "edge_leader");
+ VARRAY_TREE_INIT (stmt_list, 25, "stmt_list");
+ leader_has_match = BITMAP_ALLOC (NULL);
+ }
+ else
+ {
+#ifdef ENABLE_CHECKING
+ gcc_assert (VARRAY_ACTIVE_SIZE (edge_leader) == 0);
+ gcc_assert (VARRAY_ACTIVE_SIZE (stmt_list) == 0);
+ gcc_assert (bitmap_empty_p (leader_has_match));
+#endif
+ }
+
+ /* 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)
+ {
+ if (PENDING_STMT (e))
+ {
+ bool found = false;
+
+ /* Look for the same stmt list in edge leaders list. */
+ for (x = 0; x < VARRAY_ACTIVE_SIZE (edge_leader); x++)
+ {
+ edge leader = VARRAY_EDGE (edge_leader, x);
+ 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;
+ }
+ }
+
+ /* If no similar stmt list, add this edge to the leader list. */
+ if (!found)
+ {
+ VARRAY_PUSH_EDGE (edge_leader, e);
+ VARRAY_PUSH_TREE (stmt_list, PENDING_STMT (e));
+ }
+ }
+ }
+
+ /* If there are no similar lists, just issue the stmts. */
+ if (!have_opportunity)
+ {
+ for (x = 0; x < VARRAY_ACTIVE_SIZE (edge_leader); x++)
+ bsi_commit_one_edge_insert (VARRAY_EDGE (edge_leader, x), NULL);
+ VARRAY_POP_ALL (edge_leader);
+ VARRAY_POP_ALL (stmt_list);
+ bitmap_clear (leader_has_match);
+ return;
+ }
+
+
+ if (debug_file)
+ fprintf (debug_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 ; x < VARRAY_ACTIVE_SIZE (edge_leader); x++)
+ if (bitmap_bit_p (leader_has_match, x))
+ {
+ edge new_edge, leader_edge;
+ block_stmt_iterator bsi;
+ tree curr_stmt_list;
+
+ leader_match = leader_edge = VARRAY_EDGE (edge_leader, x);
+
+ /* The tree_* cfg manipulation routines use the PENDING_EDGE field
+ for various PHI manipulations, so it gets cleared whhen calls are
+ made to make_forwarder_block(). So make sure the edge is clear,
+ and use the saved stmt list. */
+ PENDING_STMT (leader_edge) = NULL;
+ leader_edge->aux = leader_edge;
+ curr_stmt_list = VARRAY_TREE (stmt_list, x);
+
+ new_edge = make_forwarder_block (leader_edge->dest, same_stmt_list_p,
+ NULL);
+ bb = new_edge->dest;
+ if (debug_file)
+ {
+ fprintf (debug_file, "Splitting BB %d for Common stmt list. ",
+ leader_edge->dest->index);
+ fprintf (debug_file, "Original block is now BB%d.\n", bb->index);
+ print_generic_stmt (debug_file, curr_stmt_list, TDF_VOPS);
+ }
+
+ FOR_EACH_EDGE (e, ei, new_edge->src->preds)
+ {
+ e->aux = NULL;
+ if (debug_file)
+ fprintf (debug_file, " Edge (%d->%d) lands here.\n",
+ e->src->index, e->dest->index);
+ }
+
+ bsi = bsi_last (leader_edge->dest);
+ bsi_insert_after (&bsi, curr_stmt_list, BSI_NEW_STMT);
+
+ leader_match = NULL;
+ /* We should never get a new block now. */
+ }
+ else
+ {
+ e = VARRAY_EDGE (edge_leader, x);
+ PENDING_STMT (e) = VARRAY_TREE (stmt_list, x);
+ bsi_commit_one_edge_insert (e, NULL);
+ }
+
+
+ /* Clear the working data structures. */
+ VARRAY_POP_ALL (edge_leader);
+ VARRAY_POP_ALL (stmt_list);
+ bitmap_clear (leader_has_match);
+}
+
+
+/* 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, and if non-NULL, debug information is printed via
+ DUMP_FILE. */
+
+static void
+perform_edge_inserts (FILE *dump_file)
+{
+ basic_block bb;
+
+ 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);
+
+ FOR_EACH_BB (bb)
+ analyze_edges_for_bb (bb, dump_file);
+
+ analyze_edges_for_bb (EXIT_BLOCK_PTR, dump_file);
+
+ /* Clear out any tables which were created. */
+ edge_leader = NULL;
+ BITMAP_FREE (leader_has_match);
+
+#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
}
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);
}
}
+ /* we no longer maintain the SSA operand cache at this point. */
+ fini_ssa_operands ();
+
+ /* If any copies were inserted on edges, analyze and insert them now. */
+ perform_edge_inserts (dump_file);
+
dump_file = save;
}
+/* 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
+insert_backedge_copies (void)
+{
+ basic_block bb;
+
+ FOR_EACH_BB (bb)
+ {
+ tree phi;
+
+ for (phi = phi_nodes (bb); phi; phi = PHI_CHAIN (phi))
+ {
+ tree result = PHI_RESULT (phi);
+ tree result_var;
+ int i;
+
+ if (!is_gimple_reg (result))
+ continue;
+
+ 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 and
+ we are not combining temporaries, then we will
+ need a copy statement. */
+ if ((e->flags & EDGE_DFS_BACK)
+ && (TREE_CODE (arg) != SSA_NAME
+ || (!flag_tree_combine_temps
+ && 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;
+ }
+
+ /* Create a new instance of the underlying
+ variable of the PHI result. */
+ stmt = build (MODIFY_EXPR, TREE_TYPE (result_var),
+ NULL, PHI_ARG_DEF (phi, i));
+ name = make_ssa_name (result_var, stmt);
+ TREE_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);
+ }
+ }
+ }
+ }
+}
+
/* 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. */
{
var_map map;
int var_flags = 0;
- int ssa_flags = (SSANORM_REMOVE_ALL_PHIS | SSANORM_USE_COALESCE_LIST);
+ int ssa_flags = 0;
+
+ /* 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 ();
if (!flag_tree_live_range_split)
ssa_flags |= SSANORM_COALESCE_PARTITIONS;
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 */
+ TODO_dump_func | TODO_ggc_collect, /* todo_flags_finish */
+ 0 /* letter */
};
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