/* Generic SSA value propagation engine.
- Copyright (C) 2004, 2005, 2006, 2007, 2008 Free Software Foundation, Inc.
+ Copyright (C) 2004, 2005, 2006, 2007, 2008, 2009, 2010, 2011
+ Free Software Foundation, Inc.
Contributed by Diego Novillo <dnovillo@redhat.com>
This file is part of GCC.
#include "tm.h"
#include "tree.h"
#include "flags.h"
-#include "rtl.h"
#include "tm_p.h"
-#include "ggc.h"
#include "basic-block.h"
#include "output.h"
-#include "expr.h"
#include "function.h"
-#include "diagnostic.h"
+#include "gimple-pretty-print.h"
#include "timevar.h"
#include "tree-dump.h"
#include "tree-flow.h"
#include "tree-pass.h"
#include "tree-ssa-propagate.h"
#include "langhooks.h"
-#include "varray.h"
#include "vec.h"
#include "value-prof.h"
#include "gimple.h"
/* Add a basic block to the worklist. The block must not be already
in the worklist, and it must not be the ENTRY or EXIT block. */
-static void
+static void
cfg_blocks_add (basic_block bb)
{
bool head = false;
for (si = gsi_start_bb (bb); !gsi_end_p (si); gsi_next (&si))
gimple_set_plf (gsi_stmt (si), STMT_IN_SSA_EDGE_WORKLIST, false);
-
+
for (si = gsi_start_phis (bb); !gsi_end_p (si); gsi_next (&si))
gimple_set_plf (gsi_stmt (si), STMT_IN_SSA_EDGE_WORKLIST, false);
}
break;
- case TRUTH_NOT_EXPR:
- if (!is_gimple_val (TREE_OPERAND (expr, 0)))
- return false;
- break;
-
- case TRUTH_AND_EXPR:
- case TRUTH_XOR_EXPR:
- case TRUTH_OR_EXPR:
- if (!is_gimple_val (TREE_OPERAND (expr, 0))
- || !is_gimple_val (TREE_OPERAND (expr, 1)))
- return false;
- break;
-
default:
+ if (get_gimple_rhs_class (code) == GIMPLE_TERNARY_RHS)
+ {
+ if (((code == VEC_COND_EXPR || code == COND_EXPR)
+ ? !is_gimple_condexpr (TREE_OPERAND (expr, 0))
+ : !is_gimple_val (TREE_OPERAND (expr, 0)))
+ || !is_gimple_val (TREE_OPERAND (expr, 1))
+ || !is_gimple_val (TREE_OPERAND (expr, 2)))
+ return false;
+ break;
+ }
return false;
}
break;
as a single GIMPLE_CALL statement. If the arguments require
further gimplification, return false. */
-bool
+static bool
valid_gimple_call_p (tree expr)
{
unsigned i, nargs;
nargs = call_expr_nargs (expr);
for (i = 0; i < nargs; i++)
- if (! is_gimple_operand (CALL_EXPR_ARG (expr, i)))
- return false;
+ {
+ tree arg = CALL_EXPR_ARG (expr, i);
+ if (is_gimple_reg_type (arg))
+ {
+ if (!is_gimple_val (arg))
+ return false;
+ }
+ else
+ if (!is_gimple_lvalue (arg))
+ return false;
+ }
return true;
}
}
}
+/* Helper function for update_gimple_call and update_call_from_tree.
+ A GIMPLE_CALL STMT is being replaced with GIMPLE_CALL NEW_STMT. */
+
+static void
+finish_update_gimple_call (gimple_stmt_iterator *si_p, gimple new_stmt,
+ gimple stmt)
+{
+ gimple_call_set_lhs (new_stmt, gimple_call_lhs (stmt));
+ move_ssa_defining_stmt_for_defs (new_stmt, stmt);
+ gimple_set_vuse (new_stmt, gimple_vuse (stmt));
+ gimple_set_vdef (new_stmt, gimple_vdef (stmt));
+ gimple_set_location (new_stmt, gimple_location (stmt));
+ if (gimple_block (new_stmt) == NULL_TREE)
+ gimple_set_block (new_stmt, gimple_block (stmt));
+ gsi_replace (si_p, new_stmt, false);
+}
+
+/* Update a GIMPLE_CALL statement at iterator *SI_P to call to FN
+ with number of arguments NARGS, where the arguments in GIMPLE form
+ follow NARGS argument. */
+
+bool
+update_gimple_call (gimple_stmt_iterator *si_p, tree fn, int nargs, ...)
+{
+ va_list ap;
+ gimple new_stmt, stmt = gsi_stmt (*si_p);
+
+ gcc_assert (is_gimple_call (stmt));
+ va_start (ap, nargs);
+ new_stmt = gimple_build_call_valist (fn, nargs, ap);
+ finish_update_gimple_call (si_p, new_stmt, stmt);
+ va_end (ap);
+ return true;
+}
/* Update a GIMPLE_CALL statement at iterator *SI_P to reflect the
value of EXPR, which is expected to be the result of folding the
bool
update_call_from_tree (gimple_stmt_iterator *si_p, tree expr)
{
- tree lhs;
-
gimple stmt = gsi_stmt (*si_p);
- gcc_assert (is_gimple_call (stmt));
-
- lhs = gimple_call_lhs (stmt);
-
if (valid_gimple_call_p (expr))
{
/* The call has simplified to another call. */
{
args = VEC_alloc (tree, heap, nargs);
VEC_safe_grow (tree, heap, args, nargs);
-
+
for (i = 0; i < nargs; i++)
VEC_replace (tree, args, i, CALL_EXPR_ARG (expr, i));
}
new_stmt = gimple_build_call_vec (fn, args);
- gimple_call_set_lhs (new_stmt, lhs);
- move_ssa_defining_stmt_for_defs (new_stmt, stmt);
- gimple_set_vuse (new_stmt, gimple_vuse (stmt));
- gimple_set_vdef (new_stmt, gimple_vdef (stmt));
- gimple_set_location (new_stmt, gimple_location (stmt));
- gsi_replace (si_p, new_stmt, false);
+ finish_update_gimple_call (si_p, new_stmt, stmt);
VEC_free (tree, heap, args);
return true;
}
else if (valid_gimple_rhs_p (expr))
{
+ tree lhs = gimple_call_lhs (stmt);
gimple new_stmt;
/* The call has simplified to an expression
/* No value is expected, and EXPR has no effect.
Replace it with an empty statement. */
new_stmt = gimple_build_nop ();
- unlink_stmt_vdef (stmt);
- release_defs (stmt);
+ if (gimple_in_ssa_p (cfun))
+ {
+ unlink_stmt_vdef (stmt);
+ release_defs (stmt);
+ }
}
else
{
lhs = create_tmp_var (TREE_TYPE (expr), NULL);
new_stmt = gimple_build_assign (lhs, expr);
add_referenced_var (lhs);
- lhs = make_ssa_name (lhs, new_stmt);
+ if (gimple_in_ssa_p (cfun))
+ lhs = make_ssa_name (lhs, new_stmt);
gimple_assign_set_lhs (new_stmt, lhs);
gimple_set_vuse (new_stmt, gimple_vuse (stmt));
gimple_set_vdef (new_stmt, gimple_vdef (stmt));
ssa_prop_init ();
/* Iterate until the worklists are empty. */
- while (!cfg_blocks_empty_p ()
+ while (!cfg_blocks_empty_p ()
|| VEC_length (gimple, interesting_ssa_edges) > 0
|| VEC_length (gimple, varying_ssa_edges) > 0)
{
PROP_VALUE. Return true if at least one reference was replaced. */
static bool
-replace_uses_in (gimple stmt, prop_value_t *prop_value)
+replace_uses_in (gimple stmt, ssa_prop_get_value_fn get_value)
{
bool replaced = false;
use_operand_p use;
FOR_EACH_SSA_USE_OPERAND (use, stmt, iter, SSA_OP_USE)
{
tree tuse = USE_FROM_PTR (use);
- tree val = prop_value[SSA_NAME_VERSION (tuse)].value;
+ tree val = (*get_value) (tuse);
if (val == tuse || val == NULL_TREE)
continue;
values from PROP_VALUE. */
static void
-replace_phi_args_in (gimple phi, prop_value_t *prop_value)
+replace_phi_args_in (gimple phi, ssa_prop_get_value_fn get_value)
{
size_t i;
bool replaced = false;
if (TREE_CODE (arg) == SSA_NAME)
{
- tree val = prop_value[SSA_NAME_VERSION (arg)].value;
+ tree val = (*get_value) (arg);
if (val && val != arg && may_propagate_copy (arg, val))
{
}
}
}
-
+
if (dump_file && (dump_flags & TDF_DETAILS))
{
if (!replaced)
If FOLD_FN is non-NULL the function will be invoked on all statements
before propagating values for pass specific simplification.
+ DO_DCE is true if trivially dead stmts can be removed.
+
+ If DO_DCE is true, the statements within a BB are walked from
+ last to first element. Otherwise we scan from first to last element.
+
Return TRUE when something changed. */
bool
-substitute_and_fold (prop_value_t *prop_value, ssa_prop_fold_stmt_fn fold_fn)
+substitute_and_fold (ssa_prop_get_value_fn get_value_fn,
+ ssa_prop_fold_stmt_fn fold_fn,
+ bool do_dce)
{
basic_block bb;
bool something_changed = false;
+ unsigned i;
- if (prop_value == NULL && !fold_fn)
+ if (!get_value_fn && !fold_fn)
return false;
if (dump_file && (dump_flags & TDF_DETAILS))
memset (&prop_stats, 0, sizeof (prop_stats));
- /* Substitute values in every statement of every basic block. */
+ /* Substitute lattice values at definition sites. */
+ if (get_value_fn)
+ for (i = 1; i < num_ssa_names; ++i)
+ {
+ tree name = ssa_name (i);
+ tree val;
+ gimple def_stmt;
+ gimple_stmt_iterator gsi;
+
+ if (!name
+ || !is_gimple_reg (name))
+ continue;
+
+ def_stmt = SSA_NAME_DEF_STMT (name);
+ if (gimple_nop_p (def_stmt)
+ /* Do not substitute ASSERT_EXPR rhs, this will confuse VRP. */
+ || (gimple_assign_single_p (def_stmt)
+ && gimple_assign_rhs_code (def_stmt) == ASSERT_EXPR)
+ || !(val = (*get_value_fn) (name))
+ || !may_propagate_copy (name, val))
+ continue;
+
+ gsi = gsi_for_stmt (def_stmt);
+ if (is_gimple_assign (def_stmt))
+ {
+ gimple_assign_set_rhs_with_ops (&gsi, TREE_CODE (val),
+ val, NULL_TREE);
+ gcc_assert (gsi_stmt (gsi) == def_stmt);
+ if (maybe_clean_eh_stmt (def_stmt))
+ gimple_purge_dead_eh_edges (gimple_bb (def_stmt));
+ update_stmt (def_stmt);
+ }
+ else if (is_gimple_call (def_stmt))
+ {
+ if (update_call_from_tree (&gsi, val)
+ && maybe_clean_or_replace_eh_stmt (def_stmt, gsi_stmt (gsi)))
+ gimple_purge_dead_eh_edges (gimple_bb (gsi_stmt (gsi)));
+ }
+ else if (gimple_code (def_stmt) == GIMPLE_PHI)
+ {
+ gimple new_stmt = gimple_build_assign (name, val);
+ gimple_stmt_iterator gsi2;
+ SSA_NAME_DEF_STMT (name) = new_stmt;
+ gsi2 = gsi_after_labels (gimple_bb (def_stmt));
+ gsi_insert_before (&gsi2, new_stmt, GSI_SAME_STMT);
+ remove_phi_node (&gsi, false);
+ }
+
+ something_changed = true;
+ }
+
+ /* Propagate into all uses and fold. */
FOR_EACH_BB (bb)
{
gimple_stmt_iterator i;
/* Propagate known values into PHI nodes. */
- if (prop_value)
+ if (get_value_fn)
for (i = gsi_start_phis (bb); !gsi_end_p (i); gsi_next (&i))
- replace_phi_args_in (gsi_stmt (i), prop_value);
+ replace_phi_args_in (gsi_stmt (i), get_value_fn);
- /* Propagate known values into stmts. Do a backward walk to expose
- more trivially deletable stmts. */
- for (i = gsi_last_bb (bb); !gsi_end_p (i);)
+ /* Propagate known values into stmts. Do a backward walk if
+ do_dce is true. In some case it exposes
+ more trivially deletable stmts to walk backward. */
+ for (i = (do_dce ? gsi_last_bb (bb) : gsi_start_bb (bb)); !gsi_end_p (i);)
{
bool did_replace;
gimple stmt = gsi_stmt (i);
gimple old_stmt;
enum gimple_code code = gimple_code (stmt);
+ gimple_stmt_iterator oldi;
+
+ oldi = i;
+ if (do_dce)
+ gsi_prev (&i);
+ else
+ gsi_next (&i);
/* Ignore ASSERT_EXPRs. They are used by VRP to generate
range information for names and they are discarded
if (code == GIMPLE_ASSIGN
&& TREE_CODE (gimple_assign_rhs1 (stmt)) == ASSERT_EXPR)
- {
- gsi_prev (&i);
- continue;
- }
+ continue;
/* No point propagating into a stmt whose result is not used,
- but instead we might be able to remove a trivially dead stmt. */
- if (gimple_get_lhs (stmt)
+ but instead we might be able to remove a trivially dead stmt.
+ Don't do this when called from VRP, since the SSA_NAME which
+ is going to be released could be still referenced in VRP
+ ranges. */
+ if (do_dce
+ && gimple_get_lhs (stmt)
&& TREE_CODE (gimple_get_lhs (stmt)) == SSA_NAME
&& has_zero_uses (gimple_get_lhs (stmt))
&& !stmt_could_throw_p (stmt)
fprintf (dump_file, "\n");
}
prop_stats.num_dce++;
- gsi_prev (&i);
i2 = gsi_for_stmt (stmt);
gsi_remove (&i2, true);
release_defs (stmt);
specific information. Do this before propagating
into the stmt to not disturb pass specific information. */
if (fold_fn
- && (*fold_fn)(&i))
+ && (*fold_fn)(&oldi))
{
did_replace = true;
prop_stats.num_stmts_folded++;
+ stmt = gsi_stmt (oldi);
+ update_stmt (stmt);
}
- /* Only replace real uses if we couldn't fold the
- statement using value range information. */
- if (prop_value
- && !did_replace)
- did_replace |= replace_uses_in (stmt, prop_value);
+ /* Replace real uses in the statement. */
+ if (get_value_fn)
+ did_replace |= replace_uses_in (stmt, get_value_fn);
/* If we made a replacement, fold the statement. */
if (did_replace)
- fold_stmt (&i);
+ fold_stmt (&oldi);
/* Now cleanup. */
if (did_replace)
{
- stmt = gsi_stmt (i);
+ stmt = gsi_stmt (oldi);
/* If we cleaned up EH information from the statement,
remove EH edges. */
== GIMPLE_SINGLE_RHS))
{
tree rhs = gimple_assign_rhs1 (stmt);
-
+
if (TREE_CODE (rhs) == ADDR_EXPR)
recompute_tree_invariant_for_addr_expr (rhs);
}
else
fprintf (dump_file, "Not folded\n");
}
-
- gsi_prev (&i);
}
}
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