It may help to think of this as first moving the earlier store to
the point immediately before the later store. Again, the single
- use of the virtual defintion and the post-dominance relationship
+ use of the virtual definition and the post-dominance relationship
ensure that such movement would be safe. Clearly if there are
back to back stores, then the second is redundant.
static void fix_stmt_v_may_defs (tree, tree);
static void record_voperand_set (bitmap, bitmap *, unsigned int);
+static unsigned max_stmt_uid; /* Maximal uid of a statement. Uids to phi
+ nodes are assigned using the versions of
+ ssa names they define. */
+
+/* Returns uid of statement STMT. */
+
+static unsigned
+get_stmt_uid (tree stmt)
+{
+ if (TREE_CODE (stmt) == PHI_NODE)
+ return SSA_NAME_VERSION (PHI_RESULT (stmt)) + max_stmt_uid;
+
+ 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. */
them with the appropriate V_MAY_DEF_OP. */
for (j = 0; j < PHI_NUM_ARGS (phi); j++)
if (v_may_def == PHI_ARG_DEF (phi, j))
- PHI_ARG_DEF (phi, j) = V_MAY_DEF_OP (v_may_defs, i);
+ SET_PHI_ARG_DEF (phi, j, V_MAY_DEF_OP (v_may_defs, i));
}
}
if (v_may_def1 == V_MAY_DEF_RESULT (v_may_defs2, j))
{
/* Update. */
- *V_MAY_DEF_OP_PTR (v_may_defs1, i) =
- V_MAY_DEF_OP (v_may_defs2, j);
+ SET_V_MAY_DEF_OP (v_may_defs1, i, V_MAY_DEF_OP (v_may_defs2, j));
break;
}
}
-#ifdef ENABLE_CHECKING
/* If we did not find a corresponding V_MAY_DEF_RESULT, then something
has gone terribly wrong. */
- if (j == NUM_V_MAY_DEFS (v_may_defs2))
- abort ();
-#endif
-
+ gcc_assert (j != NUM_V_MAY_DEFS (v_may_defs2));
}
}
if (NUM_V_MAY_DEFS (v_may_defs) == 0)
return;
- /* We know we have virtual definitions. If this is a MODIFY_EXPR, then
- record it into our table. */
- if (TREE_CODE (stmt) == MODIFY_EXPR
- && TREE_CODE (TREE_OPERAND (stmt, 1)) != CALL_EXPR)
+ /* We know we have virtual definitions. If this is a MODIFY_EXPR that's
+ not also a function call, then record it into our table. */
+ if (get_call_expr_in (stmt))
+ return;
+ if (TREE_CODE (stmt) == MODIFY_EXPR)
{
dataflow_t df = get_immediate_uses (stmt);
unsigned int num_uses = num_immediate_uses (df);
same block. */
while (num_uses == 1
&& TREE_CODE (use) == PHI_NODE
- && bitmap_bit_p (dse_gd->stores, stmt_ann (use)->uid))
+ && bitmap_bit_p (dse_gd->stores, get_stmt_uid (use)))
{
/* Record the first PHI we skip so that we can fix its
uses if we find that STMT is a dead store. */
/* If we have precisely one immediate use at this point, then we may
have found redundant store. */
if (num_uses == 1
- && bitmap_bit_p (dse_gd->stores, stmt_ann (use)->uid)
+ && bitmap_bit_p (dse_gd->stores, get_stmt_uid (use))
&& operand_equal_p (TREE_OPERAND (stmt, 0),
TREE_OPERAND (use, 0), 0))
{
This allows us to cascade dead stores. */
redirect_immediate_uses (stmt, skipped_phi ? skipped_phi : use);
+ /* Be sure to remove any dataflow information attached to
+ this statement. */
+ free_df_for_stmt (stmt);
+
+ /* And release any SSA_NAMEs set in this statement back to the
+ SSA_NAME manager. */
+ release_defs (stmt);
+
/* Finally remove the dead store. */
bsi_remove (&bsi);
}
if (need_imm_uses_for (PHI_RESULT (phi)))
record_voperand_set (dse_gd->stores,
&bd->stores,
- get_stmt_ann (phi)->uid);
+ get_stmt_uid (phi));
}
static void
struct dse_global_data *dse_gd = walk_data->global_data;
bitmap stores = dse_gd->stores;
unsigned int i;
+ bitmap_iterator bi;
/* Unwind the stores noted in this basic block. */
if (bd->stores)
- EXECUTE_IF_SET_IN_BITMAP (bd->stores, 0, i, bitmap_clear_bit (stores, i););
+ EXECUTE_IF_SET_IN_BITMAP (bd->stores, 0, i, bi)
+ {
+ bitmap_clear_bit (stores, i);
+ }
}
static void
{
struct dom_walk_data walk_data;
struct dse_global_data dse_gd;
- unsigned int uid = 0;
basic_block bb;
/* Create a UID for each statement in the function. Ordering of the
UIDs is not important for this pass. */
+ max_stmt_uid = 0;
FOR_EACH_BB (bb)
{
block_stmt_iterator bsi;
- tree phi;
for (bsi = bsi_start (bb); !bsi_end_p (bsi); bsi_next (&bsi))
- stmt_ann (bsi_stmt (bsi))->uid = uid++;
-
- for (phi = phi_nodes (bb); phi; phi = PHI_CHAIN (phi))
- stmt_ann (phi)->uid = uid++;
+ stmt_ann (bsi_stmt (bsi))->uid = max_stmt_uid++;
}
/* We might consider making this a property of each pass so that it
NULL, /* next */
0, /* static_pass_number */
TV_TREE_DSE, /* tv_id */
- PROP_cfg | PROP_ssa, /* properties_required */
+ 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
+ | TODO_verify_ssa,
+ 0 /* letter */
};
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