/* CFG cleanup for trees.
- Copyright (C) 2001, 2002, 2003, 2004, 2005, 2006, 2007
+ Copyright (C) 2001, 2002, 2003, 2004, 2005, 2006, 2007, 2008, 2009, 2010
Free Software Foundation, Inc.
This file is part of GCC.
return false;
}
+
/* Disconnect an unreachable block in the control expression starting
at block BB. */
static bool
-cleanup_control_expr_graph (basic_block bb, block_stmt_iterator bsi)
+cleanup_control_expr_graph (basic_block bb, gimple_stmt_iterator gsi)
{
edge taken_edge;
bool retval = false;
- tree expr = bsi_stmt (bsi), val;
+ gimple stmt = gsi_stmt (gsi);
+ tree val;
if (!single_succ_p (bb))
{
edge e;
edge_iterator ei;
bool warned;
+ location_t loc;
fold_defer_overflow_warnings ();
-
- switch (TREE_CODE (expr))
+ loc = gimple_location (stmt);
+ switch (gimple_code (stmt))
{
- case COND_EXPR:
- val = fold (COND_EXPR_COND (expr));
- break;
-
- case SWITCH_EXPR:
- val = fold (SWITCH_COND (expr));
- if (TREE_CODE (val) != INTEGER_CST)
- {
- fold_undefer_and_ignore_overflow_warnings ();
- return false;
- }
+ case GIMPLE_COND:
+ {
+ tree lhs = gimple_cond_lhs (stmt);
+ tree rhs = gimple_cond_rhs (stmt);
+ /* For conditions try harder and lookup single-argument
+ PHI nodes. Only do so from the same basic-block though
+ as other basic-blocks may be dead already. */
+ if (TREE_CODE (lhs) == SSA_NAME
+ && !name_registered_for_update_p (lhs))
+ {
+ gimple def_stmt = SSA_NAME_DEF_STMT (lhs);
+ if (gimple_code (def_stmt) == GIMPLE_PHI
+ && gimple_phi_num_args (def_stmt) == 1
+ && gimple_bb (def_stmt) == gimple_bb (stmt)
+ && (TREE_CODE (PHI_ARG_DEF (def_stmt, 0)) != SSA_NAME
+ || !name_registered_for_update_p (PHI_ARG_DEF (def_stmt,
+ 0))))
+ lhs = PHI_ARG_DEF (def_stmt, 0);
+ }
+ if (TREE_CODE (rhs) == SSA_NAME
+ && !name_registered_for_update_p (rhs))
+ {
+ gimple def_stmt = SSA_NAME_DEF_STMT (rhs);
+ if (gimple_code (def_stmt) == GIMPLE_PHI
+ && gimple_phi_num_args (def_stmt) == 1
+ && gimple_bb (def_stmt) == gimple_bb (stmt)
+ && (TREE_CODE (PHI_ARG_DEF (def_stmt, 0)) != SSA_NAME
+ || !name_registered_for_update_p (PHI_ARG_DEF (def_stmt,
+ 0))))
+ rhs = PHI_ARG_DEF (def_stmt, 0);
+ }
+ val = fold_binary_loc (loc, gimple_cond_code (stmt),
+ boolean_type_node, lhs, rhs);
+ break;
+ }
+
+ case GIMPLE_SWITCH:
+ val = gimple_switch_index (stmt);
break;
default:
- gcc_unreachable ();
+ val = NULL_TREE;
}
-
taken_edge = find_taken_edge (bb, val);
if (!taken_edge)
{
if (!warned)
{
fold_undefer_overflow_warnings
- (true, expr, WARN_STRICT_OVERFLOW_CONDITIONAL);
+ (true, stmt, WARN_STRICT_OVERFLOW_CONDITIONAL);
warned = true;
}
taken_edge = single_succ_edge (bb);
bitmap_set_bit (cfgcleanup_altered_bbs, bb->index);
- bsi_remove (&bsi, true);
+ gsi_remove (&gsi, true);
taken_edge->flags = EDGE_FALLTHRU;
return retval;
static bool
cleanup_control_flow_bb (basic_block bb)
{
- block_stmt_iterator bsi;
+ gimple_stmt_iterator gsi;
bool retval = false;
- tree stmt;
+ gimple stmt;
/* If the last statement of the block could throw and now cannot,
we need to prune cfg. */
- retval |= tree_purge_dead_eh_edges (bb);
+ retval |= gimple_purge_dead_eh_edges (bb);
- bsi = bsi_last (bb);
- if (bsi_end_p (bsi))
+ gsi = gsi_last_bb (bb);
+ if (gsi_end_p (gsi))
return retval;
- stmt = bsi_stmt (bsi);
+ stmt = gsi_stmt (gsi);
- if (TREE_CODE (stmt) == COND_EXPR
- || TREE_CODE (stmt) == SWITCH_EXPR)
- retval |= cleanup_control_expr_graph (bb, bsi);
- /* If we had a computed goto which has a compile-time determinable
- destination, then we can eliminate the goto. */
- else if (TREE_CODE (stmt) == GOTO_EXPR
- && TREE_CODE (GOTO_DESTINATION (stmt)) == ADDR_EXPR
- && (TREE_CODE (TREE_OPERAND (GOTO_DESTINATION (stmt), 0))
+ if (gimple_code (stmt) == GIMPLE_COND
+ || gimple_code (stmt) == GIMPLE_SWITCH)
+ retval |= cleanup_control_expr_graph (bb, gsi);
+ else if (gimple_code (stmt) == GIMPLE_GOTO
+ && TREE_CODE (gimple_goto_dest (stmt)) == ADDR_EXPR
+ && (TREE_CODE (TREE_OPERAND (gimple_goto_dest (stmt), 0))
== LABEL_DECL))
{
+ /* If we had a computed goto which has a compile-time determinable
+ destination, then we can eliminate the goto. */
edge e;
tree label;
edge_iterator ei;
/* First look at all the outgoing edges. Delete any outgoing
edges which do not go to the right block. For the one
edge which goes to the right block, fix up its flags. */
- label = TREE_OPERAND (GOTO_DESTINATION (stmt), 0);
+ label = TREE_OPERAND (gimple_goto_dest (stmt), 0);
target_block = label_to_block (label);
for (ei = ei_start (bb->succs); (e = ei_safe_edge (ei)); )
{
/* Remove the GOTO_EXPR as it is not needed. The CFG has all the
relevant information we need. */
- bsi_remove (&bsi, true);
+ gsi_remove (&gsi, true);
retval = true;
}
/* Check for indirect calls that have been turned into
noreturn calls. */
- else if (noreturn_call_p (stmt) && remove_fallthru_edge (bb->succs))
+ else if (is_gimple_call (stmt)
+ && gimple_call_noreturn_p (stmt)
+ && remove_fallthru_edge (bb->succs))
retval = true;
return retval;
static bool
tree_forwarder_block_p (basic_block bb, bool phi_wanted)
{
- block_stmt_iterator bsi;
- edge_iterator ei;
- edge e, succ;
- basic_block dest;
+ gimple_stmt_iterator gsi;
/* BB must have a single outgoing edge. */
if (single_succ_p (bb) != 1
/* If PHI_WANTED is false, BB must not have any PHI nodes.
Otherwise, BB must have PHI nodes. */
- || (phi_nodes (bb) != NULL_TREE) != phi_wanted
+ || gimple_seq_empty_p (phi_nodes (bb)) == phi_wanted
/* BB may not be a predecessor of EXIT_BLOCK_PTR. */
|| single_succ (bb) == EXIT_BLOCK_PTR
/* Nor should this be an infinite loop. */
gcc_assert (bb != ENTRY_BLOCK_PTR);
#endif
+ /* There should not be an edge coming from entry, or an EH edge. */
+ {
+ edge_iterator ei;
+ edge e;
+
+ FOR_EACH_EDGE (e, ei, bb->preds)
+ if (e->src == ENTRY_BLOCK_PTR || (e->flags & EDGE_EH))
+ return false;
+ }
+
/* Now walk through the statements backward. We can ignore labels,
anything else means this is not a forwarder block. */
- for (bsi = bsi_last (bb); !bsi_end_p (bsi); bsi_prev (&bsi))
+ for (gsi = gsi_last_bb (bb); !gsi_end_p (gsi); gsi_prev (&gsi))
{
- tree stmt = bsi_stmt (bsi);
+ gimple stmt = gsi_stmt (gsi);
- switch (TREE_CODE (stmt))
+ switch (gimple_code (stmt))
{
- case LABEL_EXPR:
- if (DECL_NONLOCAL (LABEL_EXPR_LABEL (stmt)))
+ case GIMPLE_LABEL:
+ if (DECL_NONLOCAL (gimple_label_label (stmt)))
return false;
break;
+ /* ??? For now, hope there's a corresponding debug
+ assignment at the destination. */
+ case GIMPLE_DEBUG:
+ break;
+
default:
return false;
}
}
- if (find_edge (ENTRY_BLOCK_PTR, bb))
- return false;
-
if (current_loops)
{
basic_block dest;
if (dest->loop_father->header == dest)
return false;
}
-
- /* If we have an EH edge leaving this block, make sure that the
- destination of this block has only one predecessor. This ensures
- that we don't get into the situation where we try to remove two
- forwarders that go to the same basic block but are handlers for
- different EH regions. */
- succ = single_succ_edge (bb);
- dest = succ->dest;
- FOR_EACH_EDGE (e, ei, bb->preds)
- {
- if (e->flags & EDGE_EH)
- {
- if (!single_pred_p (dest))
- return false;
- }
- }
-
return true;
}
{
int n1 = e1->dest_idx;
int n2 = e2->dest_idx;
- tree phi;
+ gimple_stmt_iterator gsi;
- for (phi = phi_nodes (dest); phi; phi = PHI_CHAIN (phi))
+ for (gsi = gsi_start_phis (dest); !gsi_end_p (gsi); gsi_next (&gsi))
{
- tree val1 = PHI_ARG_DEF (phi, n1);
- tree val2 = PHI_ARG_DEF (phi, n2);
+ gimple phi = gsi_stmt (gsi);
+ tree val1 = gimple_phi_arg_def (phi, n1);
+ tree val2 = gimple_phi_arg_def (phi, n2);
gcc_assert (val1 != NULL_TREE);
gcc_assert (val2 != NULL_TREE);
{
edge succ = single_succ_edge (bb), e, s;
basic_block dest = succ->dest;
- tree label;
- tree phi;
+ gimple label;
edge_iterator ei;
- block_stmt_iterator bsi, bsi_to;
- bool seen_abnormal_edge = false;
+ gimple_stmt_iterator gsi, gsi_to;
+ bool can_move_debug_stmts;
/* We check for infinite loops already in tree_forwarder_block_p.
However it may happen that the infinite loop is created
if (dest == bb)
return false;
- /* If the destination block consists of a nonlocal label, do not merge
- it. */
+ /* If the destination block consists of a nonlocal label or is a
+ EH landing pad, do not merge it. */
label = first_stmt (dest);
if (label
- && TREE_CODE (label) == LABEL_EXPR
- && DECL_NONLOCAL (LABEL_EXPR_LABEL (label)))
+ && gimple_code (label) == GIMPLE_LABEL
+ && (DECL_NONLOCAL (gimple_label_label (label))
+ || EH_LANDING_PAD_NR (gimple_label_label (label)) != 0))
return false;
/* If there is an abnormal edge to basic block BB, but not into
So if there is an abnormal edge to BB, proceed only if there is
no abnormal edge to DEST and there are no phi nodes in DEST. */
- if (has_abnormal_incoming_edge_p (bb))
- {
- seen_abnormal_edge = true;
-
- if (has_abnormal_incoming_edge_p (dest)
- || phi_nodes (dest) != NULL_TREE)
- return false;
- }
+ if (has_abnormal_incoming_edge_p (bb)
+ && (has_abnormal_incoming_edge_p (dest)
+ || !gimple_seq_empty_p (phi_nodes (dest))))
+ return false;
/* If there are phi nodes in DEST, and some of the blocks that are
predecessors of BB are also predecessors of DEST, check that the
phi node arguments match. */
- if (phi_nodes (dest))
+ if (!gimple_seq_empty_p (phi_nodes (dest)))
{
FOR_EACH_EDGE (e, ei, bb->preds)
{
}
}
+ can_move_debug_stmts = single_pred_p (dest);
+
/* Redirect the edges. */
for (ei = ei_start (bb->preds); (e = ei_safe_edge (ei)); )
{
{
/* Create arguments for the phi nodes, since the edge was not
here before. */
- for (phi = phi_nodes (dest); phi; phi = PHI_CHAIN (phi))
- add_phi_arg (phi, PHI_ARG_DEF (phi, succ->dest_idx), s);
+ for (gsi = gsi_start_phis (dest);
+ !gsi_end_p (gsi);
+ gsi_next (&gsi))
+ {
+ gimple phi = gsi_stmt (gsi);
+ source_location l = gimple_phi_arg_location_from_edge (phi, succ);
+ add_phi_arg (phi, gimple_phi_arg_def (phi, succ->dest_idx), s, l);
+ }
}
}
- if (seen_abnormal_edge)
+ /* Move nonlocal labels and computed goto targets as well as user
+ defined labels and labels with an EH landing pad number to the
+ new block, so that the redirection of the abnormal edges works,
+ jump targets end up in a sane place and debug information for
+ labels is retained. */
+ gsi_to = gsi_start_bb (dest);
+ for (gsi = gsi_start_bb (bb); !gsi_end_p (gsi); )
{
- /* Move the labels to the new block, so that the redirection of
- the abnormal edges works. */
+ tree decl;
+ label = gsi_stmt (gsi);
+ if (is_gimple_debug (label))
+ break;
+ decl = gimple_label_label (label);
+ if (EH_LANDING_PAD_NR (decl) != 0
+ || DECL_NONLOCAL (decl)
+ || FORCED_LABEL (decl)
+ || !DECL_ARTIFICIAL (decl))
+ {
+ gsi_remove (&gsi, false);
+ gsi_insert_before (&gsi_to, label, GSI_SAME_STMT);
+ }
+ else
+ gsi_next (&gsi);
+ }
- bsi_to = bsi_start (dest);
- for (bsi = bsi_start (bb); !bsi_end_p (bsi); )
+ /* Move debug statements if the destination has just a single
+ predecessor. */
+ if (can_move_debug_stmts)
+ {
+ gsi_to = gsi_after_labels (dest);
+ for (gsi = gsi_after_labels (bb); !gsi_end_p (gsi); )
{
- label = bsi_stmt (bsi);
- gcc_assert (TREE_CODE (label) == LABEL_EXPR);
- bsi_remove (&bsi, false);
- bsi_insert_before (&bsi_to, label, BSI_CONTINUE_LINKING);
+ gimple debug = gsi_stmt (gsi);
+ if (!is_gimple_debug (debug))
+ break;
+ gsi_remove (&gsi, false);
+ gsi_insert_before (&gsi_to, debug, GSI_SAME_STMT);
}
}
split_bbs_on_noreturn_calls (void)
{
bool changed = false;
- tree stmt;
+ gimple stmt;
basic_block bb;
/* Detect cases where a mid-block call is now known not to return. */
if (cfun->gimple_df)
- while (VEC_length (tree, MODIFIED_NORETURN_CALLS (cfun)))
+ while (VEC_length (gimple, MODIFIED_NORETURN_CALLS (cfun)))
{
- stmt = VEC_pop (tree, MODIFIED_NORETURN_CALLS (cfun));
- bb = bb_for_stmt (stmt);
+ stmt = VEC_pop (gimple, MODIFIED_NORETURN_CALLS (cfun));
+ bb = gimple_bb (stmt);
+ /* BB might be deleted at this point, so verify first
+ BB is present in the cfg. */
if (bb == NULL
+ || bb->index < NUM_FIXED_BLOCKS
+ || bb->index >= n_basic_blocks
+ || BASIC_BLOCK (bb->index) != bb
|| last_stmt (bb) == stmt
- || !noreturn_call_p (stmt))
+ || !gimple_call_noreturn_p (stmt))
continue;
changed = true;
return changed;
}
+/* If GIMPLE_OMP_RETURN in basic block BB is unreachable, remove it. */
+
+static bool
+cleanup_omp_return (basic_block bb)
+{
+ gimple stmt = last_stmt (bb);
+ basic_block control_bb;
+
+ if (stmt == NULL
+ || gimple_code (stmt) != GIMPLE_OMP_RETURN
+ || !single_pred_p (bb))
+ return false;
+
+ control_bb = single_pred (bb);
+ stmt = last_stmt (control_bb);
+
+ if (stmt == NULL || gimple_code (stmt) != GIMPLE_OMP_SECTIONS_SWITCH)
+ return false;
+
+ /* The block with the control statement normally has two entry edges -- one
+ from entry, one from continue. If continue is removed, return is
+ unreachable, so we remove it here as well. */
+ if (EDGE_COUNT (control_bb->preds) == 2)
+ return false;
+
+ gcc_assert (EDGE_COUNT (control_bb->preds) == 1);
+ remove_edge_and_dominated_blocks (single_pred_edge (bb));
+ return true;
+}
+
/* Tries to cleanup cfg in basic block BB. Returns true if anything
changes. */
{
bool retval = false;
+ if (cleanup_omp_return (bb))
+ return true;
+
retval = cleanup_control_flow_bb (bb);
/* Forwarder blocks can carry line number information which is
useful when debugging, so we only clean them up when
optimizing. */
-
if (optimize > 0
&& tree_forwarder_block_p (bb, false)
&& remove_forwarder_block (bb))
calls. */
retval |= split_bbs_on_noreturn_calls ();
}
-
+
end_recording_case_labels ();
BITMAP_FREE (cfgcleanup_altered_bbs);
return retval;
/* Remove unreachable blocks and other miscellaneous clean up work.
Return true if the flowgraph was modified, false otherwise. */
-bool
-cleanup_tree_cfg (void)
+static bool
+cleanup_tree_cfg_noloop (void)
{
bool changed;
timevar_pop (TV_TREE_CLEANUP_CFG);
+ if (changed && current_loops)
+ loops_state_set (LOOPS_NEED_FIXUP);
+
return changed;
}
-/* Cleanup cfg and repair loop structures. */
+/* Repairs loop structures. */
-bool
-cleanup_tree_cfg_loop (void)
+static void
+repair_loop_structures (void)
{
- bool changed = cleanup_tree_cfg ();
+ bitmap changed_bbs = BITMAP_ALLOC (NULL);
+ fix_loop_structure (changed_bbs);
- if (changed && current_loops != NULL)
- {
- bitmap changed_bbs = BITMAP_ALLOC (NULL);
- fix_loop_structure (changed_bbs);
+ /* This usually does nothing. But sometimes parts of cfg that originally
+ were inside a loop get out of it due to edge removal (since they
+ become unreachable by back edges from latch). */
+ if (loops_state_satisfies_p (LOOP_CLOSED_SSA))
+ rewrite_into_loop_closed_ssa (changed_bbs, TODO_update_ssa);
- /* This usually does nothing. But sometimes parts of cfg that originally
- were inside a loop get out of it due to edge removal (since they
- become unreachable by back edges from latch). */
- if ((current_loops->state & LOOP_CLOSED_SSA) != 0)
- rewrite_into_loop_closed_ssa (changed_bbs, TODO_update_ssa);
-
- BITMAP_FREE (changed_bbs);
+ BITMAP_FREE (changed_bbs);
#ifdef ENABLE_CHECKING
- verify_loop_structure ();
+ verify_loop_structure ();
#endif
- scev_reset ();
- }
+ scev_reset ();
+
+ loops_state_clear (LOOPS_NEED_FIXUP);
+}
+
+/* Cleanup cfg and repair loop structures. */
+
+bool
+cleanup_tree_cfg (void)
+{
+ bool changed = cleanup_tree_cfg_noloop ();
+
+ if (current_loops != NULL
+ && loops_state_satisfies_p (LOOPS_NEED_FIXUP))
+ repair_loop_structures ();
+
return changed;
}
{
edge succ = single_succ_edge (bb);
basic_block dest = succ->dest;
- tree label;
+ gimple label;
basic_block dombb, domdest, dom;
/* We check for infinite loops already in tree_forwarder_block_p.
merge it. */
label = first_stmt (dest);
if (label
- && TREE_CODE (label) == LABEL_EXPR
- && DECL_NONLOCAL (LABEL_EXPR_LABEL (label)))
+ && gimple_code (label) == GIMPLE_LABEL
+ && DECL_NONLOCAL (gimple_label_label (label)))
return;
/* Redirect each incoming edge to BB to DEST. */
while (EDGE_COUNT (bb->preds) > 0)
{
edge e = EDGE_PRED (bb, 0), s;
- tree phi;
+ gimple_stmt_iterator gsi;
s = find_edge (e->src, dest);
if (s)
if (phi_alternatives_equal (dest, s, succ))
{
e = redirect_edge_and_branch (e, dest);
- PENDING_STMT (e) = NULL_TREE;
+ redirect_edge_var_map_clear (e);
continue;
}
/* Add to the PHI nodes at DEST each PHI argument removed at the
destination of E. */
- for (phi = phi_nodes (dest); phi; phi = PHI_CHAIN (phi))
+ for (gsi = gsi_start_phis (dest);
+ !gsi_end_p (gsi);
+ gsi_next (&gsi))
{
- tree def = PHI_ARG_DEF (phi, succ->dest_idx);
+ gimple phi = gsi_stmt (gsi);
+ tree def = gimple_phi_arg_def (phi, succ->dest_idx);
+ source_location locus = gimple_phi_arg_location_from_edge (phi, succ);
if (TREE_CODE (def) == SSA_NAME)
{
- tree var;
+ edge_var_map_vector head;
+ edge_var_map *vm;
+ size_t i;
/* If DEF is one of the results of PHI nodes removed during
redirection, replace it with the PHI argument that used
to be on E. */
- for (var = PENDING_STMT (e); var; var = TREE_CHAIN (var))
+ head = redirect_edge_var_map_vector (e);
+ for (i = 0; VEC_iterate (edge_var_map, head, i, vm); ++i)
{
- tree old_arg = TREE_PURPOSE (var);
- tree new_arg = TREE_VALUE (var);
+ tree old_arg = redirect_edge_var_map_result (vm);
+ tree new_arg = redirect_edge_var_map_def (vm);
if (def == old_arg)
{
def = new_arg;
+ locus = redirect_edge_var_map_location (vm);
break;
}
}
}
- add_phi_arg (phi, def, s);
+ add_phi_arg (phi, def, s, locus);
}
- PENDING_STMT (e) = NULL;
+ redirect_edge_var_map_clear (e);
}
/* Update the dominators. */
/* We have to feed into another basic block with PHI
nodes. */
- if (!phi_nodes (dest)
+ if (gimple_seq_empty_p (phi_nodes (dest))
/* We don't want to deal with a basic block with
abnormal edges. */
|| has_abnormal_incoming_edge_p (bb))
}
else
{
- tree phi;
+ gimple_stmt_iterator gsi;
unsigned int dest_idx = single_succ_edge (bb)->dest_idx;
/* BB dominates DEST. There may be many users of the PHI
can handle. If the result of every PHI in BB is used
only by a PHI in DEST, then we can trivially merge the
PHI nodes from BB into DEST. */
- for (phi = phi_nodes (bb); phi; phi = PHI_CHAIN (phi))
+ for (gsi = gsi_start_phis (bb); !gsi_end_p (gsi);
+ gsi_next (&gsi))
{
- tree result = PHI_RESULT (phi);
+ gimple phi = gsi_stmt (gsi);
+ tree result = gimple_phi_result (phi);
use_operand_p imm_use;
- tree use_stmt;
+ gimple use_stmt;
/* If the PHI's result is never used, then we can just
ignore it. */
/* Get the single use of the result of this PHI node. */
if (!single_imm_use (result, &imm_use, &use_stmt)
- || TREE_CODE (use_stmt) != PHI_NODE
- || bb_for_stmt (use_stmt) != dest
- || PHI_ARG_DEF (use_stmt, dest_idx) != result)
+ || gimple_code (use_stmt) != GIMPLE_PHI
+ || gimple_bb (use_stmt) != dest
+ || gimple_phi_arg_def (use_stmt, dest_idx) != result)
break;
}
/* If the loop above iterated through all the PHI nodes
in BB, then we can merge the PHIs from BB into DEST. */
- if (!phi)
+ if (gsi_end_p (gsi))
*current++ = bb;
}
}
return 1;
}
-struct tree_opt_pass pass_merge_phi = {
+struct gimple_opt_pass pass_merge_phi =
+{
+ {
+ GIMPLE_PASS,
"mergephi", /* name */
gate_merge_phi, /* gate */
merge_phi_nodes, /* execute */
0, /* properties_destroyed */
0, /* todo_flags_start */
TODO_dump_func | TODO_ggc_collect /* todo_flags_finish */
- | TODO_verify_ssa,
- 0 /* letter */
+ | TODO_verify_ssa
+ }
};
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