/* Dead store elimination
- Copyright (C) 2004, 2005, 2006 Free Software Foundation, Inc.
+ Copyright (C) 2004, 2005, 2006, 2007 Free Software Foundation, Inc.
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 "system.h"
bool recycled)
{
struct dse_block_local_data *bd
- = VEC_last (void_p, walk_data->block_data_stack);
+ = (struct dse_block_local_data *)
+ VEC_last (void_p, walk_data->block_data_stack);
/* If we are given a recycled block local data structure, ensure any
bitmap associated with the block is cleared. */
memory_ssa_name_same (tree *expr_p, int *walk_subtrees ATTRIBUTE_UNUSED,
void *data)
{
- struct address_walk_data *walk_data = data;
+ struct address_walk_data *walk_data = (struct address_walk_data *) data;
tree expr = *expr_p;
tree def_stmt;
basic_block def_bb;
== NULL);
}
+/* Return the use stmt for the lhs of STMT following the virtual
+ def-use chains. Returns the MODIFY_EXPR stmt which lhs is equal to
+ the lhs of STMT or NULL_TREE if no such stmt can be found. */
+static tree
+get_use_of_stmt_lhs (tree stmt,
+ use_operand_p * first_use_p,
+ use_operand_p * use_p, tree * use_stmt)
+{
+ tree usevar, lhs;
+ def_operand_p def_p;
+
+ if (TREE_CODE (stmt) != GIMPLE_MODIFY_STMT)
+ return NULL_TREE;
+
+ lhs = GIMPLE_STMT_OPERAND (stmt, 0);
+
+ /* The stmt must have a single VDEF. */
+ def_p = SINGLE_SSA_DEF_OPERAND (stmt, SSA_OP_VDEF);
+ if (def_p == NULL_DEF_OPERAND_P)
+ return NULL_TREE;
+
+ if (!has_single_use (DEF_FROM_PTR (def_p)))
+ return NULL_TREE;
+ /* Get the immediate use of the def. */
+ single_imm_use (DEF_FROM_PTR (def_p), use_p, use_stmt);
+ gcc_assert (*use_p != NULL_USE_OPERAND_P);
+ first_use_p = use_p;
+ if (TREE_CODE (*use_stmt) != GIMPLE_MODIFY_STMT)
+ return NULL_TREE;
+
+ do
+ {
+ /* Look at the use stmt and see if it's LHS matches
+ stmt's lhs SSA_NAME. */
+ def_p = SINGLE_SSA_DEF_OPERAND (*use_stmt, SSA_OP_VDEF);
+ if (def_p == NULL_DEF_OPERAND_P)
+ return NULL_TREE;
+
+ usevar = GIMPLE_STMT_OPERAND (*use_stmt, 0);
+ if (operand_equal_p (usevar, lhs, 0))
+ return *use_stmt;
+
+ if (!has_single_use (DEF_FROM_PTR (def_p)))
+ return NULL_TREE;
+ single_imm_use (DEF_FROM_PTR (def_p), use_p, use_stmt);
+ gcc_assert (*use_p != NULL_USE_OPERAND_P);
+ if (TREE_CODE (*use_stmt) != GIMPLE_MODIFY_STMT)
+ return NULL_TREE;
+ }
+ while (1);
+
+ return NULL_TREE;
+}
/* A helper of dse_optimize_stmt.
Given a GIMPLE_MODIFY_STMT in STMT, check that each VDEF has one
block_stmt_iterator bsi)
{
struct dse_block_local_data *bd
- = VEC_last (void_p, walk_data->block_data_stack);
- struct dse_global_data *dse_gd = walk_data->global_data;
+ = (struct dse_block_local_data *)
+ VEC_last (void_p, walk_data->block_data_stack);
+ struct dse_global_data *dse_gd
+ = (struct dse_global_data *) walk_data->global_data;
tree stmt = bsi_stmt (bsi);
stmt_ann_t ann = stmt_ann (stmt);
/* If this is a partial store into an aggregate, record it. */
dse_record_partial_aggregate_store (stmt, dse_gd);
- /* If we have precisely one immediate use at this point, then we may
- have found redundant store. Make sure that the stores are to
- the same memory location. This includes checking that any
- SSA-form variables in the address will have the same values. */
+ if (use_p != NULL_USE_OPERAND_P
+ && bitmap_bit_p (dse_gd->stores, get_stmt_uid (use_stmt))
+ && (!operand_equal_p (GIMPLE_STMT_OPERAND (stmt, 0),
+ GIMPLE_STMT_OPERAND (use_stmt, 0), 0)
+ && !dse_partial_kill_p (stmt, dse_gd))
+ && memory_address_same (stmt, use_stmt))
+ {
+ /* If we have precisely one immediate use at this point, but
+ the stores are not to the same memory location then walk the
+ virtual def-use chain to get the stmt which stores to that same
+ memory location. */
+ if (get_use_of_stmt_lhs (stmt, &first_use_p, &use_p, &use_stmt) ==
+ NULL_TREE)
+ {
+ record_voperand_set (dse_gd->stores, &bd->stores, ann->uid);
+ return;
+ }
+ }
+
+ /* If we have precisely one immediate use at this point and the
+ stores are to the same memory location or there is a chain of
+ virtual uses from stmt and the stmt which stores to that same
+ memory location, then we may have found redundant store. */
if (use_p != NULL_USE_OPERAND_P
&& bitmap_bit_p (dse_gd->stores, get_stmt_uid (use_stmt))
&& (operand_equal_p (GIMPLE_STMT_OPERAND (stmt, 0),
dse_record_phis (struct dom_walk_data *walk_data, basic_block bb)
{
struct dse_block_local_data *bd
- = VEC_last (void_p, walk_data->block_data_stack);
- struct dse_global_data *dse_gd = walk_data->global_data;
+ = (struct dse_block_local_data *)
+ VEC_last (void_p, walk_data->block_data_stack);
+ struct dse_global_data *dse_gd
+ = (struct dse_global_data *) walk_data->global_data;
tree phi;
for (phi = phi_nodes (bb); phi; phi = PHI_CHAIN (phi))
basic_block bb ATTRIBUTE_UNUSED)
{
struct dse_block_local_data *bd
- = VEC_last (void_p, walk_data->block_data_stack);
- struct dse_global_data *dse_gd = walk_data->global_data;
+ = (struct dse_block_local_data *)
+ VEC_last (void_p, walk_data->block_data_stack);
+ struct dse_global_data *dse_gd
+ = (struct dse_global_data *) walk_data->global_data;
bitmap stores = dse_gd->stores;
unsigned int i;
bitmap_iterator bi;
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