return stmt_ann (stmt)->uid;
}
-/* Function indicating whether we ought to include information for 'var'
- when calculating immediate uses. For this pass we only want use
- information for virtual variables. */
-
-static bool
-need_imm_uses_for (tree var)
-{
- return !is_gimple_reg (var);
-}
-
-
/* Set bit UID in bitmaps GLOBAL and *LOCAL, creating *LOCAL as needed. */
+
static void
record_voperand_set (bitmap global, bitmap *local, unsigned int uid)
{
bitmap_set_bit (*local, uid);
bitmap_set_bit (global, uid);
}
+
/* Initialize block local data structures. */
static void
tree stmt = bsi_stmt (bsi);
stmt_ann_t ann = stmt_ann (stmt);
v_may_def_optype v_may_defs;
+ v_must_def_optype v_must_defs;
- get_stmt_operands (stmt);
v_may_defs = V_MAY_DEF_OPS (ann);
+ v_must_defs = V_MUST_DEF_OPS (ann);
/* If this statement has no virtual defs, then there is nothing
to do. */
- if (NUM_V_MAY_DEFS (v_may_defs) == 0)
+ if (NUM_V_MAY_DEFS (v_may_defs) == 0
+ && NUM_V_MUST_DEFS (v_must_defs) == 0)
return;
/* We know we have virtual definitions. If this is a MODIFY_EXPR that's
if (TREE_CODE (stmt) == MODIFY_EXPR)
{
- unsigned int num_uses = 0, count = 0;
use_operand_p first_use_p = NULL_USE_OPERAND_P;
- use_operand_p use_p;
- tree use, use_stmt;
+ use_operand_p use_p = NULL;
+ tree use, use_stmt, temp;
tree defvar = NULL_TREE, usevar = NULL_TREE;
+ bool fail = false;
use_operand_p var2;
def_operand_p var1;
ssa_op_iter op_iter;
- FOR_EACH_SSA_MAYDEF_OPERAND (var1, var2, stmt, op_iter)
- {
+ /* We want to verify that each virtual definition in STMT has
+ precisely one use and that all the virtual definitions are
+ used by the same single statement. When complete, we
+ want USE_STMT to refer to the one statment which uses
+ all of the virtual definitions from STMT. */
+ use_stmt = NULL;
+ FOR_EACH_SSA_MUST_AND_MAY_DEF_OPERAND (var1, var2, stmt, op_iter)
+ {
defvar = DEF_FROM_PTR (var1);
usevar = USE_FROM_PTR (var2);
- num_uses += num_imm_uses (defvar);
- count++;
- if (num_uses > 1 || count > 1)
- break;
- }
- if (count == 1 && num_uses == 1)
- {
- single_imm_use (defvar, &use_p, &use_stmt);
+ /* If this virtual def does not have precisely one use, then
+ we will not be able to eliminate STMT. */
+ if (num_imm_uses (defvar) != 1)
+ {
+ fail = true;
+ break;
+ }
+
+ /* Get the one and only immediate use of DEFVAR. */
+ single_imm_use (defvar, &use_p, &temp);
gcc_assert (use_p != NULL_USE_OPERAND_P);
first_use_p = use_p;
use = USE_FROM_PTR (use_p);
+
+ /* If the immediate use of DEF_VAR is not the same as the
+ previously find immediate uses, then we will not be able
+ to eliminate STMT. */
+ if (use_stmt == NULL)
+ use_stmt = temp;
+ else if (temp != use_stmt)
+ {
+ fail = true;
+ break;
+ }
}
- else
+
+ if (fail)
{
record_voperand_set (dse_gd->stores, &bd->stores, ann->uid);
return;
represents the only use of this store.
Note this does not handle the case where the store has
- multiple V_MAY_DEFs which all reach a set of PHI nodes in the
+ multiple V_{MAY,MUST}_DEFs which all reach a set of PHI nodes in the
same block. */
while (use_p != NULL_USE_OPERAND_P
&& TREE_CODE (use_stmt) == PHI_NODE
&& operand_equal_p (TREE_OPERAND (stmt, 0),
TREE_OPERAND (use_stmt, 0), 0))
{
+ tree def;
+ ssa_op_iter iter;
+
/* Make sure we propagate the ABNORMAL bit setting. */
if (SSA_NAME_OCCURS_IN_ABNORMAL_PHI (USE_FROM_PTR (first_use_p)))
SSA_NAME_OCCURS_IN_ABNORMAL_PHI (usevar) = 1;
/* Remove the dead store. */
bsi_remove (&bsi);
+ /* The virtual defs for the dead statement will need to be
+ updated. Since these names are going to disappear,
+ FUD chains for uses downstream need to be updated. */
+ FOR_EACH_SSA_TREE_OPERAND (def, stmt, iter, SSA_OP_VIRTUAL_DEFS)
+ mark_sym_for_renaming (SSA_NAME_VAR (def));
+
/* And release any SSA_NAMEs set in this statement back to the
SSA_NAME manager. */
release_defs (stmt);
tree phi;
for (phi = phi_nodes (bb); phi; phi = PHI_CHAIN (phi))
- if (need_imm_uses_for (PHI_RESULT (phi)))
+ if (!is_gimple_reg (PHI_RESULT (phi)))
record_voperand_set (dse_gd->stores,
&bd->stores,
get_stmt_uid (phi));
walk_data.after_dom_children_before_stmts = NULL;
walk_data.after_dom_children_walk_stmts = NULL;
walk_data.after_dom_children_after_stmts = dse_finalize_block;
+ walk_data.interesting_blocks = NULL;
walk_data.block_local_data_size = sizeof (struct dse_block_local_data);
NULL, /* next */
0, /* static_pass_number */
TV_TREE_DSE, /* tv_id */
- PROP_cfg | PROP_ssa
+ PROP_cfg
+ | PROP_ssa
| PROP_alias, /* properties_required */
0, /* properties_provided */
0, /* properties_destroyed */
0, /* todo_flags_start */
- TODO_dump_func | TODO_ggc_collect /* todo_flags_finish */
- | TODO_verify_ssa,
- 0 /* letter */
+ TODO_dump_func
+ | TODO_ggc_collect
+ | TODO_update_ssa
+ | TODO_verify_ssa, /* todo_flags_finish */
+ 0 /* letter */
};
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