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tree-pass.h (pass_eliminate_useless_stores): Remove.

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2005-12-23  Daniel Berlin  <dberlin@dberlin.org>

	* tree-pass.h (pass_eliminate_useless_stores): Remove.
	* tree-ssa-pre.c (is_copy_stmt): Ditto.
	(follow_copies_till_vuse): Ditto.
	(do_eustore): Ditto.
	(gate_eustores): Ditto.
	(pass_eliminate_useless_stores): Ditto.
	* passes.c (init_optimization_passes): Ditto.

From-SVN: r109034
This commit is contained in:
Daniel Berlin 2005-12-24 04:42:48 +00:00 committed by Daniel Berlin
parent 3961348422
commit 097d5d18f0
5 changed files with 10 additions and 148 deletions
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10
gcc/ChangeLog
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@ -1,3 +1,13 @@
2005-12-23 Daniel Berlin <dberlin@dberlin.org>
* tree-pass.h (pass_eliminate_useless_stores): Remove.
* tree-ssa-pre.c (is_copy_stmt): Ditto.
(follow_copies_till_vuse): Ditto.
(do_eustore): Ditto.
(gate_eustores): Ditto.
(pass_eliminate_useless_stores): Ditto.
* passes.c (init_optimization_passes): Ditto.
2005-12-23 Paolo Bonzini <bonzini@gnu.org>
* combine.c (simplify_shift_const): Fix typo. Use, whenever

1
gcc/passes.c
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@ -498,7 +498,6 @@ init_optimization_passes (void)
NEXT_PASS (pass_return_slot);
NEXT_PASS (pass_rename_ssa_copies);
NEXT_PASS (pass_early_warn_uninitialized);
NEXT_PASS (pass_eliminate_useless_stores);
/* Initial scalar cleanups. */
NEXT_PASS (pass_ccp);

14
gcc/testsuite/gcc.dg/tree-ssa/ssa-eustores.c
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@ -1,14 +0,0 @@
/* { dg-do compile } */
/* { dg-options "-O2 -fdump-tree-eustores-all" } */
static int a;
int foo()
{
int alocal;
int b;
alocal = a;
b = alocal;
a = b;
}
/* We should eliminate the store back to a. */
/* { dg-final { scan-tree-dump-times "Eliminating useless store" 1 "eustores"} } */
/* { dg-final { cleanup-tree-dump "eustores" } } */

1
gcc/tree-pass.h
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@ -285,7 +285,6 @@ extern struct tree_opt_pass pass_uncprop;
extern struct tree_opt_pass pass_return_slot;
extern struct tree_opt_pass pass_reassoc;
extern struct tree_opt_pass pass_rebuild_cgraph_edges;
extern struct tree_opt_pass pass_eliminate_useless_stores;
/* IPA Passes */
extern struct tree_opt_pass pass_ipa_cp;

132
gcc/tree-ssa-pre.c
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@ -2928,135 +2928,3 @@ struct tree_opt_pass pass_fre =
0 /* letter */
};
/* Return true if T is a copy statement between two ssa names. */
static bool
is_copy_stmt (tree t)
{
if (!t || TREE_CODE (t) != MODIFY_EXPR)
return false;
if (TREE_CODE (TREE_OPERAND (t, 0)) == SSA_NAME
&& TREE_CODE (TREE_OPERAND (t, 1)) == SSA_NAME)
return true;
return false;
}
/* Starting from START, walk copy statements till we hit a statement with a
VUSE or a non-copy statement. */
static tree
follow_copies_till_vuse (tree start)
{
if (is_copy_stmt (start) && ZERO_SSA_OPERANDS (start, SSA_OP_VIRTUAL_USES))
{
tree rhs, defstmt;
rhs = TREE_OPERAND (start, 1);
defstmt = SSA_NAME_DEF_STMT (rhs);
return follow_copies_till_vuse (defstmt);
}
return start;
}
/* Gate and execute functions for eliminate useless stores.
The goal here is to recognize the pattern *x = ... *x, and eliminate the
store because the value hasn't changed. Store copy/const prop won't
do this because making *more* loads (IE propagating *x) is not a win, so it
ignores them.
This pass is currently geared completely towards static variable store
elimination. */
static void
do_eustores (void)
{
basic_block bb;
/* For each basic block
For each statement (STMT) in the block
if STMT is a stores of the pattern *x = y
follow the chain of definitions for y, until we hit a non-copy
statement or a statement with a vuse.
if the statement we arrive at is a vuse of the operand we killed,
accessed through the same memory operation, then we have a
useless store (because it is *x = ... = *x). */
FOR_EACH_BB (bb)
{
block_stmt_iterator bsi;
for (bsi = bsi_start (bb);
!bsi_end_p (bsi);)
{
tree stmt = bsi_stmt (bsi);
tree startat;
tree kill;
tree found;
if (NUM_SSA_OPERANDS (stmt, SSA_OP_VMUSTDEF) != 1
|| TREE_CODE (stmt) != MODIFY_EXPR
|| TREE_CODE (TREE_OPERAND (stmt, 1)) != SSA_NAME)
{
bsi_next (&bsi);
continue;
}
kill = MUSTDEF_KILL (MUSTDEF_OPS (stmt));
startat = TREE_OPERAND (stmt, 1);
startat = SSA_NAME_DEF_STMT (startat);
found = follow_copies_till_vuse (startat);
if (found && TREE_CODE (found) == MODIFY_EXPR)
{
/* We want exactly one virtual use, and it should match up with
the use being killed. */
if (NUM_SSA_OPERANDS (found, SSA_OP_VUSE) != 1
|| VUSE_OP (VUSE_OPS (found)) != kill
|| !DECL_P (TREE_OPERAND (stmt, 0))
|| !operand_equal_p (TREE_OPERAND (found, 1),
TREE_OPERAND (stmt, 0), 0))
{
bsi_next (&bsi);
continue;
}
if (dump_file)
{
fprintf (dump_file, "Eliminating useless store ");
print_generic_stmt (dump_file, stmt, 0);
}
mark_sym_for_renaming (TREE_OPERAND (stmt, 0));
bsi_remove (&bsi);
}
else
{
bsi_next (&bsi);
continue;
}
}
}
}
static bool
gate_eustores(void)
{
return flag_unit_at_a_time != 0;
}
struct tree_opt_pass pass_eliminate_useless_stores =
{
"eustores", /* name */
gate_eustores, /* gate */
do_eustores, /* execute */
NULL, /* sub */
NULL, /* next */
0, /* static_pass_number */
0, /* tv_id */
PROP_cfg | PROP_ssa | PROP_alias, /* properties_required */
0, /* properties_provided */
0, /* properties_destroyed */
0, /* todo_flags_start */
TODO_update_ssa | TODO_dump_func
| TODO_ggc_collect | TODO_verify_ssa, /* todo_flags_finish */
0 /* letter */
};