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, 59 Temple Place - Suite 330,
-Boston, MA 02111-1307, USA. */
+the Free Software Foundation, 51 Franklin Street, Fifth Floor,
+Boston, MA 02110-1301, USA. */
#include "config.h"
#include "system.h"
#include "coretypes.h"
#include "tm.h"
-#include "errors.h"
#include "ggc.h"
#include "tree.h"
#include "rtl.h"
if (!is_gimple_val (t))
return NULL_TREE;
- new_cond = build (cond_code, boolean_type_node, op0, t);
+ new_cond = build2 (cond_code, boolean_type_node, op0, t);
}
}
if (has_single_use (test_var))
{
/* TEST_VAR was set from a relational operator. */
- new_cond = build (TREE_CODE (def_rhs),
- boolean_type_node, op0, op1);
+ new_cond = build2 (TREE_CODE (def_rhs),
+ boolean_type_node, op0, op1);
/* Invert the conditional if necessary. */
if ((cond_code == EQ_EXPR
tidy_after_forward_propagate_addr (tree stmt)
{
mark_new_vars_to_rename (stmt);
- update_stmt (stmt);
/* We may have turned a trapping insn into a non-trapping insn. */
if (maybe_clean_or_replace_eh_stmt (stmt, stmt)
&& tree_purge_dead_eh_edges (bb_for_stmt (stmt)))
cfg_changed = true;
+
+ if (TREE_CODE (TREE_OPERAND (stmt, 1)) == ADDR_EXPR)
+ recompute_tree_invariant_for_addr_expr (TREE_OPERAND (stmt, 1));
+
+ update_stmt (stmt);
}
/* STMT defines LHS which is contains the address of the 0th element
/* STMT is a statement of the form SSA_NAME = ADDR_EXPR <whatever>.
- Try to forward propagate the ADDR_EXPR into the uses of the SSA_NAME.
+ Try to forward propagate the ADDR_EXPR into the use USE_STMT.
Often this will allow for removal of an ADDR_EXPR and INDIRECT_REF
- node or for recovery of array indexing from pointer arithmetic. */
+ node or for recovery of array indexing from pointer arithmetic.
+ Return true, if the propagation was successful. */
static bool
-forward_propagate_addr_expr (tree stmt)
+forward_propagate_addr_expr_1 (tree stmt, tree use_stmt)
{
- int stmt_loop_depth = bb_for_stmt (stmt)->loop_depth;
tree name = TREE_OPERAND (stmt, 0);
- use_operand_p imm_use;
- tree use_stmt, lhs, rhs, array_ref;
-
- /* We require that the SSA_NAME holding the result of the ADDR_EXPR
- be used only once. That may be overly conservative in that we
- could propagate into multiple uses. However, that would effectively
- be un-cseing the ADDR_EXPR, which is probably not what we want. */
- single_imm_use (name, &imm_use, &use_stmt);
- if (!use_stmt)
- return false;
-
- /* If the use is not in a simple assignment statement, then
- there is nothing we can do. */
- if (TREE_CODE (use_stmt) != MODIFY_EXPR)
- return false;
+ tree lhs, rhs, array_ref;
- /* If the use is in a deeper loop nest, then we do not want
- to propagate the ADDR_EXPR into the loop as that is likely
- adding expression evaluations into the loop. */
- if (bb_for_stmt (use_stmt)->loop_depth > stmt_loop_depth)
- return false;
-
- /* Strip away any outer COMPONENT_REF/ARRAY_REF nodes from the LHS. */
+ /* Strip away any outer COMPONENT_REF/ARRAY_REF nodes from the LHS.
+ ADDR_EXPR will not appear on the LHS. */
lhs = TREE_OPERAND (use_stmt, 0);
while (TREE_CODE (lhs) == COMPONENT_REF || TREE_CODE (lhs) == ARRAY_REF)
lhs = TREE_OPERAND (lhs, 0);
return true;
}
- /* Strip away any outer COMPONENT_REF/ARRAY_REF nodes from the RHS. */
+ /* Strip away any outer COMPONENT_REF, ARRAY_REF or ADDR_EXPR
+ nodes from the RHS. */
rhs = TREE_OPERAND (use_stmt, 1);
- while (TREE_CODE (rhs) == COMPONENT_REF || TREE_CODE (rhs) == ARRAY_REF)
+ while (TREE_CODE (rhs) == COMPONENT_REF
+ || TREE_CODE (rhs) == ARRAY_REF
+ || TREE_CODE (rhs) == ADDR_EXPR)
rhs = TREE_OPERAND (rhs, 0);
/* Now see if the RHS node is an INDIRECT_REF using NAME. If so,
return false;
}
+/* STMT is a statement of the form SSA_NAME = ADDR_EXPR <whatever>.
+
+ Try to forward propagate the ADDR_EXPR into all uses of the SSA_NAME.
+ Often this will allow for removal of an ADDR_EXPR and INDIRECT_REF
+ node or for recovery of array indexing from pointer arithmetic.
+ Returns true, if all uses have been propagated into. */
+
+static bool
+forward_propagate_addr_expr (tree stmt)
+{
+ int stmt_loop_depth = bb_for_stmt (stmt)->loop_depth;
+ tree name = TREE_OPERAND (stmt, 0);
+ use_operand_p imm_use;
+ imm_use_iterator iter;
+ bool all = true;
+
+ FOR_EACH_IMM_USE_SAFE (imm_use, iter, name)
+ {
+ tree use_stmt = USE_STMT (imm_use);
+
+ /* If the use is not in a simple assignment statement, then
+ there is nothing we can do. */
+ if (TREE_CODE (use_stmt) != MODIFY_EXPR)
+ {
+ all = false;
+ continue;
+ }
+
+ /* If the use is in a deeper loop nest, then we do not want
+ to propagate the ADDR_EXPR into the loop as that is likely
+ adding expression evaluations into the loop. */
+ if (bb_for_stmt (use_stmt)->loop_depth > stmt_loop_depth)
+ {
+ all = false;
+ continue;
+ }
+
+ all = forward_propagate_addr_expr_1 (stmt, use_stmt) && all;
+ }
+
+ return all;
+}
+
+/* If we have lhs = ~x (STMT), look and see if earlier we had x = ~y.
+ If so, we can change STMT into lhs = y which can later be copy
+ propagated. Similarly for negation.
+
+ This could trivially be formulated as a forward propagation
+ to immediate uses. However, we already had an implementation
+ from DOM which used backward propagation via the use-def links.
+
+ It turns out that backward propagation is actually faster as
+ there's less work to do for each NOT/NEG expression we find.
+ Backwards propagation needs to look at the statement in a single
+ backlink. Forward propagation needs to look at potentially more
+ than one forward link. */
+
+static void
+simplify_not_neg_expr (tree stmt)
+{
+ tree rhs = TREE_OPERAND (stmt, 1);
+ tree rhs_def_stmt = SSA_NAME_DEF_STMT (TREE_OPERAND (rhs, 0));
+
+ /* See if the RHS_DEF_STMT has the same form as our statement. */
+ if (TREE_CODE (rhs_def_stmt) == MODIFY_EXPR
+ && TREE_CODE (TREE_OPERAND (rhs_def_stmt, 1)) == TREE_CODE (rhs))
+ {
+ tree rhs_def_operand = TREE_OPERAND (TREE_OPERAND (rhs_def_stmt, 1), 0);
+
+ /* Verify that RHS_DEF_OPERAND is a suitable SSA_NAME. */
+ if (TREE_CODE (rhs_def_operand) == SSA_NAME
+ && ! SSA_NAME_OCCURS_IN_ABNORMAL_PHI (rhs_def_operand))
+ {
+ TREE_OPERAND (stmt, 1) = rhs_def_operand;
+ update_stmt (stmt);
+ }
+ }
+}
+
+/* STMT is a SWITCH_EXPR for which we attempt to find equivalent forms of
+ the condition which we may be able to optimize better. */
+
+static void
+simplify_switch_expr (tree stmt)
+{
+ tree cond = SWITCH_COND (stmt);
+ tree def, to, ti;
+
+ /* The optimization that we really care about is removing unnecessary
+ casts. That will let us do much better in propagating the inferred
+ constant at the switch target. */
+ if (TREE_CODE (cond) == SSA_NAME)
+ {
+ def = SSA_NAME_DEF_STMT (cond);
+ if (TREE_CODE (def) == MODIFY_EXPR)
+ {
+ def = TREE_OPERAND (def, 1);
+ if (TREE_CODE (def) == NOP_EXPR)
+ {
+ int need_precision;
+ bool fail;
+
+ def = TREE_OPERAND (def, 0);
+
+#ifdef ENABLE_CHECKING
+ /* ??? Why was Jeff testing this? We are gimple... */
+ gcc_assert (is_gimple_val (def));
+#endif
+
+ to = TREE_TYPE (cond);
+ ti = TREE_TYPE (def);
+
+ /* If we have an extension that preserves value, then we
+ can copy the source value into the switch. */
+
+ need_precision = TYPE_PRECISION (ti);
+ fail = false;
+ if (TYPE_UNSIGNED (to) && !TYPE_UNSIGNED (ti))
+ fail = true;
+ else if (!TYPE_UNSIGNED (to) && TYPE_UNSIGNED (ti))
+ need_precision += 1;
+ if (TYPE_PRECISION (to) < need_precision)
+ fail = true;
+
+ if (!fail)
+ {
+ SWITCH_COND (stmt) = def;
+ update_stmt (stmt);
+ }
+ }
+ }
+ }
+}
+
/* Main entry point for the forward propagation optimizer. */
static void
/* If this statement sets an SSA_NAME to an address,
try to propagate the address into the uses of the SSA_NAME. */
- if (TREE_CODE (stmt) == MODIFY_EXPR
- && TREE_CODE (TREE_OPERAND (stmt, 1)) == ADDR_EXPR
- && TREE_CODE (TREE_OPERAND (stmt, 0)) == SSA_NAME)
+ if (TREE_CODE (stmt) == MODIFY_EXPR)
{
- if (forward_propagate_addr_expr (stmt))
- bsi_remove (&bsi);
+ tree lhs = TREE_OPERAND (stmt, 0);
+ tree rhs = TREE_OPERAND (stmt, 1);
+
+
+ if (TREE_CODE (lhs) != SSA_NAME)
+ {
+ bsi_next (&bsi);
+ continue;
+ }
+
+ if (TREE_CODE (rhs) == ADDR_EXPR)
+ {
+ if (forward_propagate_addr_expr (stmt))
+ bsi_remove (&bsi);
+ else
+ bsi_next (&bsi);
+ }
+ else if ((TREE_CODE (rhs) == BIT_NOT_EXPR
+ || TREE_CODE (rhs) == NEGATE_EXPR)
+ && TREE_CODE (TREE_OPERAND (rhs, 0)) == SSA_NAME)
+ {
+ simplify_not_neg_expr (stmt);
+ bsi_next (&bsi);
+ }
else
bsi_next (&bsi);
}
+ else if (TREE_CODE (stmt) == SWITCH_EXPR)
+ {
+ simplify_switch_expr (stmt);
+ bsi_next (&bsi);
+ }
else if (TREE_CODE (stmt) == COND_EXPR)
{
forward_propagate_into_cond (stmt);
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