/* Routines for performing Temporary Expression Replacement (TER) in SSA trees.
- Copyright (C) 2003, 2004, 2005, 2006 Free Software Foundation, Inc.
+ Copyright (C) 2003, 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, 51 Franklin Street, Fifth Floor,
-Boston, MA 02110-1301, USA. */
+along with GCC; see the file COPYING3. If not see
+<http://www.gnu.org/licenses/>. */
#include "config.h"
#include "tree-flow.h"
#include "tree-dump.h"
#include "tree-ssa-live.h"
+#include "flags.h"
/* Temporary Expression Replacement (TER)
v_9 = (b_5 + 6) * (C * 10)
which will then have the ssa_name assigned to regular variables, and the
- resulting code which will be passed ot the expander looks something like:
+ resulting code which will be passed to the expander looks something like:
v = (b + 6) * (C * 10)
Although SSA_NAMES themselves don't change, this pass is performed after
coalescing has coalesced different SSA_NAMES together, so there could be a
definition of an SSA_NAME which is coalesced with a use that causes a
- problem. ie
+ problem, i.e.,
PHI b_5 = <b_8(2), b_14(1)>
<...>
TER implements this but stepping through the instructions in a block and
tracking potential expressions for replacement, and the partitions they are
dependent on. Expressions are represented by the SSA_NAME_VERSION of the
- DEF on the LHS of a GIMPLE_MODIFY_STMT and the expression is the RHS.
+ DEF on the LHS of a GIMPLE_ASSIGN and the expression is the RHS.
When a stmt is determined to be a possible replacement expression, the
following steps are taken:
EXPR_DECL_UID bitmap is allocated and set to the base variable UID of the
def and any uses in the expression. non-NULL means the expression is being
tracked. The UID's themselves are used to prevent TER substitution into
- accumulating sequences.
- ie
+ accumulating sequences, i.e.,
+
x = x + y
x = x + z
x = x + w
a block to clear out the KILL_LIST bitmaps at the end of each block.
NEW_REPLACEABLE_DEPENDENCIES is used as a temporary place to store
- dependencies which will be reused by the current definition. ALl the uses
+ dependencies which will be reused by the current definition. All the uses
on an expression are processed before anything else is done. If a use is
determined to be a replaceable expression AND the current stmt is also going
to be replaceable, all the dependencies of this replaceable use will be
a_2's expression 'b_5 + 6' is determined to be replaceable at the use
location. It is dependent on the partition 'b_5' is in. This is cached into
- the NEW_REPLACEABLE_DEPENDENCIES bitmap. and when v_8 is examined for
- replaceablility, it is a candidate, and it is dependent on the partition
+ the NEW_REPLACEABLE_DEPENDENCIES bitmap, and when v_8 is examined for
+ replaceability, it is a candidate, and it is dependent on the partition
b_5 is in *NOT* a_2, as well as c_4's partition.
if v_8 is also replaceable:
{
var_map map;
bitmap *partition_dependencies; /* Partitions expr is dependent on. */
- tree *replaceable_expressions; /* Replacement expression table. */
+ bitmap replaceable_expressions; /* Replacement expression table. */
bitmap *expr_decl_uids; /* Base uids of exprs. */
bitmap *kill_list; /* Expr's killed by a partition. */
int virtual_partition; /* Pseudo partition for virtual ops. */
/* Free TER table T. If there are valid replacements, return the expression
vector. */
-static tree *
+static bitmap
free_temp_expr_table (temp_expr_table_p t)
{
- tree *ret = NULL;
- unsigned i;
+ bitmap ret = NULL;
#ifdef ENABLE_CHECKING
unsigned x;
for (x = 0; x <= num_var_partitions (t->map); x++)
gcc_assert (!t->kill_list[x]);
+ for (x = 0; x < num_ssa_names; x++)
+ {
+ gcc_assert (t->expr_decl_uids[x] == NULL);
+ gcc_assert (t->partition_dependencies[x] == NULL);
+ }
#endif
BITMAP_FREE (t->partition_in_use);
+ BITMAP_FREE (t->new_replaceable_dependencies);
- for (i = 0; i <= num_ssa_names; i++)
- if (t->expr_decl_uids[i])
- BITMAP_FREE (t->expr_decl_uids[i]);
free (t->expr_decl_uids);
-
free (t->kill_list);
free (t->partition_dependencies);
+ free (t->num_in_part);
if (t->replaceable_expressions)
ret = t->replaceable_expressions;
{
if (!tab->replaceable_expressions)
return false;
- return tab->replaceable_expressions[version] != NULL_TREE;
+ return bitmap_bit_p (tab->replaceable_expressions, version);
}
/* Return TRUE if expression STMT is suitable for replacement. */
static inline bool
-is_replaceable_p (tree stmt)
+is_replaceable_p (gimple stmt)
{
- tree call_expr;
use_operand_p use_p;
- tree def, use_stmt;
+ tree def;
+ gimple use_stmt;
+ location_t locus1, locus2;
+ tree block1, block2;
/* Only consider modify stmts. */
- if (TREE_CODE (stmt) != GIMPLE_MODIFY_STMT)
+ if (!is_gimple_assign (stmt))
+ return false;
+
+ /* If the statement may throw an exception, it cannot be replaced. */
+ if (stmt_could_throw_p (stmt))
return false;
/* Punt if there is more than 1 def. */
return false;
/* If the use isn't in this block, it wont be replaced either. */
- if (bb_for_stmt (use_stmt) != bb_for_stmt (stmt))
+ if (gimple_bb (use_stmt) != gimple_bb (stmt))
+ return false;
+
+ locus1 = gimple_location (stmt);
+ block1 = gimple_block (stmt);
+
+ if (gimple_code (use_stmt) == GIMPLE_PHI)
+ {
+ locus2 = 0;
+ block2 = NULL_TREE;
+ }
+ else
+ {
+ locus2 = gimple_location (use_stmt);
+ block2 = gimple_block (use_stmt);
+ }
+
+ if (!optimize
+ && ((locus1 && locus1 != locus2) || (block1 && block1 != block2)))
return false;
/* Used in this block, but at the TOP of the block, not the end. */
- if (TREE_CODE (use_stmt) == PHI_NODE)
+ if (gimple_code (use_stmt) == GIMPLE_PHI)
return false;
/* There must be no VDEFs. */
- if (!(ZERO_SSA_OPERANDS (stmt, SSA_OP_VDEF)))
+ if (gimple_vdef (stmt))
+ return false;
+
+ /* Without alias info we can't move around loads. */
+ if (gimple_references_memory_p (stmt) && !optimize)
return false;
/* Float expressions must go through memory if float-store is on. */
if (flag_float_store
- && FLOAT_TYPE_P (TREE_TYPE (GENERIC_TREE_OPERAND (stmt, 1))))
+ && FLOAT_TYPE_P (gimple_expr_type (stmt)))
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;
- }
+ /* An assignment with a register variable on the RHS is not
+ replaceable. */
+ if (gimple_assign_rhs_code (stmt) == VAR_DECL
+ && DECL_HARD_REGISTER (gimple_assign_rhs1 (stmt)))
+ return false;
+
+ /* No function calls can be replaced. */
+ if (is_gimple_call (stmt))
+ return false;
- /* Leave any stmt with voltile operands alone as well. */
- if (stmt_ann (stmt)->has_volatile_ops)
+ /* Leave any stmt with volatile operands alone as well. */
+ if (gimple_has_volatile_ops (stmt))
return false;
-
return true;
}
}
-/* Create an expression entry fora replaceable expression. */
+/* Create an expression entry for a replaceable expression. */
static void
-process_replaceable (temp_expr_table_p tab, tree stmt)
+process_replaceable (temp_expr_table_p tab, gimple stmt)
{
tree var, def, basevar;
int version;
tab->expr_decl_uids[version] = def_vars;
/* If there are VUSES, add a dependence on virtual defs. */
- if (!ZERO_SSA_OPERANDS (stmt, SSA_OP_VUSE))
+ if (gimple_vuse (stmt))
{
make_dependent_on_partition (tab, version, VIRTUAL_PARTITION (tab));
add_to_partition_kill_list (tab, VIRTUAL_PARTITION (tab), version);
/* Mark the expression associated with VAR as replaceable, and enter
- the defining stmt into the partition_dependencies table TAB. if
+ the defining stmt into the partition_dependencies table TAB. If
MORE_REPLACING is true, accumulate the pending partition dependencies. */
static void
/* Set the replaceable expression. */
if (!tab->replaceable_expressions)
- tab->replaceable_expressions = XCNEWVEC (tree, num_ssa_names + 1);
- tab->replaceable_expressions[version] = SSA_NAME_DEF_STMT (var);
+ tab->replaceable_expressions = BITMAP_ALLOC (NULL);
+ bitmap_set_bit (tab->replaceable_expressions, version);
}
static void
find_replaceable_in_bb (temp_expr_table_p tab, basic_block bb)
{
- block_stmt_iterator bsi;
- tree stmt, def, use;
- stmt_ann_t ann;
+ gimple_stmt_iterator bsi;
+ gimple stmt;
+ tree def, use;
int partition;
var_map map = tab->map;
ssa_op_iter iter;
bool stmt_replaceable;
- for (bsi = bsi_start (bb); !bsi_end_p (bsi); bsi_next (&bsi))
+ for (bsi = gsi_start_bb (bb); !gsi_end_p (bsi); gsi_next (&bsi))
{
- stmt = bsi_stmt (bsi);
- ann = stmt_ann (stmt);
+ stmt = gsi_stmt (bsi);
+
+ if (is_gimple_debug (stmt))
+ continue;
stmt_replaceable = is_replaceable_p (stmt);
+
/* Determine if this stmt finishes an existing expression. */
FOR_EACH_SSA_TREE_OPERAND (use, stmt, iter, SSA_OP_USE)
{
/* Mark expression as replaceable unless stmt is volatile or the
def variable has the same root variable as something in the
substitution list. */
- if (ann->has_volatile_ops || same_root_var)
+ if (gimple_has_volatile_ops (stmt) || same_root_var)
finished_with_expr (tab, ver, true);
else
mark_replaceable (tab, use, stmt_replaceable);
/* A V_{MAY,MUST}_DEF kills any expression using a virtual operand,
including the current stmt. */
- if (!ZERO_SSA_OPERANDS (stmt, SSA_OP_VIRTUAL_DEFS))
+ if (gimple_vdef (stmt))
kill_virtual_exprs (tab);
}
}
NULL is returned by the function, otherwise an expression vector indexed
by SSA_NAME version numbers. */
-extern tree *
+extern bitmap
find_replaceable_exprs (var_map map)
{
basic_block bb;
temp_expr_table_p table;
- tree *ret;
+ bitmap ret;
table = new_temp_expr_table (map);
FOR_EACH_BB (bb)
{
find_replaceable_in_bb (table, bb);
- gcc_assert (bitmap_empty_p (table->partition_in_use));
-
#ifdef ENABLE_CHECKING
- {
- unsigned i;
- /* Make sure all the tables have been cleared out. */
- for (i = 0; i < num_ssa_names + 1; i++)
- {
- gcc_assert (table->partition_dependencies[i] == NULL);
- gcc_assert (table->expr_decl_uids[i] == NULL);
- if (i < num_var_partitions (map))
- gcc_assert (table->kill_list[i] == NULL);
- }
- }
+ gcc_assert (bitmap_empty_p (table->partition_in_use));
#endif
}
ret = free_temp_expr_table (table);
return ret;
-}
-
+}
/* Dump TER expression table EXPR to file F. */
-extern void
-dump_replaceable_exprs (FILE *f, tree *expr)
+void
+dump_replaceable_exprs (FILE *f, bitmap expr)
{
- tree stmt, var;
- int x;
+ tree var;
+ unsigned x;
fprintf (f, "\nReplacing Expressions\n");
- for (x = 0; x < (int)num_ssa_names; x++)
- if (expr[x])
+ for (x = 0; x < num_ssa_names; x++)
+ if (bitmap_bit_p (expr, x))
{
- stmt = expr[x];
- var = SINGLE_SSA_TREE_OPERAND (stmt, SSA_OP_DEF);
- gcc_assert (var != NULL_TREE);
+ var = ssa_name (x);
print_generic_expr (f, var, TDF_SLIM);
fprintf (f, " replace with --> ");
- print_generic_expr (f, GENERIC_TREE_OPERAND (stmt, 1),
- TDF_SLIM);
+ print_gimple_stmt (f, SSA_NAME_DEF_STMT (var), 0, TDF_SLIM);
fprintf (f, "\n");
}
fprintf (f, "\n");
exclusively to debug TER. F is the place to send debug info and T is the
table being debugged. */
-extern void
+void
debug_ter (FILE *f, temp_expr_table_p t)
{
unsigned x, y;