Makefile.in (OBJS-common): Add tree-cfgcleanup.o.

	* Makefile.in (OBJS-common): Add tree-cfgcleanup.o.
	* tree-flow.h: Add prototypes for start_recording_case_labels
	and end_recording_case_labels.
	* tree-cfg.c (start_recording_case_labels,
	end_recording_case_labels): Export.
	(cleanup_tree_cfg_loop, modified_noreturn_calls,
	cleanup_control_flow, cleanup_control_expr_graph,
	remove_fallthru_edge, phi_alternatives_equal,
	tree_forwarder_block_p, has_abnormal_incoming_edge_p,
	remove_forwarder_block, cleanup_forwarder_blocks,
	remove_forwarder_block_with_phi, merge_phi_nodes,
	gate_merge_phi, pass_merge_phi): Move to ...
	* tree-cfgcleanup.c: ... here.

From-SVN: r100302

1 files changed, 756 insertions, 0 deletions

diff --git a/gcc/tree-cfgcleanup.c b/gcc/tree-cfgcleanup.c
new file mode 100644
index 0000000..f250f1f
--- /dev/null
+++ b/gcc/tree-cfgcleanup.c
@@ -0,0 +1,756 @@
+/* CFG cleanup for trees.
+   Copyright (C) 2001, 2002, 2003, 2004, 2005 Free Software Foundation, Inc.
+
+This file is part of GCC.
+
+GCC is free software; you can redistribute it and/or modify
+it under the terms of the GNU General Public License as published by
+the Free Software Foundation; either version 2, or (at your option)
+any later version.
+
+GCC is distributed in the hope that it will be useful,
+but WITHOUT ANY WARRANTY; without even the implied warranty of
+MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+GNU General Public License for more details.
+
+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.  */
+
+#include "config.h"
+#include "system.h"
+#include "coretypes.h"
+#include "tm.h"
+#include "tree.h"
+#include "rtl.h"
+#include "tm_p.h"
+#include "hard-reg-set.h"
+#include "basic-block.h"
+#include "output.h"
+#include "errors.h"
+#include "flags.h"
+#include "function.h"
+#include "expr.h"
+#include "ggc.h"
+#include "langhooks.h"
+#include "diagnostic.h"
+#include "tree-flow.h"
+#include "timevar.h"
+#include "tree-dump.h"
+#include "tree-pass.h"
+#include "toplev.h"
+#include "except.h"
+#include "cfgloop.h"
+#include "cfglayout.h"
+#include "hashtab.h"
+#include "tree-ssa-propagate.h"
+
+/* Remove any fallthru edge from EV.  Return true if an edge was removed.  */
+
+static bool
+remove_fallthru_edge (VEC(edge,gc) *ev)
+{
+  edge_iterator ei;
+  edge e;
+
+  FOR_EACH_EDGE (e, ei, ev)
+    if ((e->flags & EDGE_FALLTHRU) != 0)
+      {
+	remove_edge (e);
+	return true;
+      }
+  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)
+{
+  edge taken_edge;
+  bool retval = false;
+  tree expr = bsi_stmt (bsi), val;
+
+  if (!single_succ_p (bb))
+    {
+      edge e;
+      edge_iterator ei;
+
+      switch (TREE_CODE (expr))
+	{
+	case COND_EXPR:
+	  val = COND_EXPR_COND (expr);
+	  break;
+
+	case SWITCH_EXPR:
+	  val = SWITCH_COND (expr);
+	  if (TREE_CODE (val) != INTEGER_CST)
+	    return false;
+	  break;
+
+	default:
+	  gcc_unreachable ();
+	}
+
+      taken_edge = find_taken_edge (bb, val);
+      if (!taken_edge)
+	return false;
+
+      /* Remove all the edges except the one that is always executed.  */
+      for (ei = ei_start (bb->succs); (e = ei_safe_edge (ei)); )
+	{
+	  if (e != taken_edge)
+	    {
+	      taken_edge->probability += e->probability;
+	      taken_edge->count += e->count;
+	      remove_edge (e);
+	      retval = true;
+	    }
+	  else
+	    ei_next (&ei);
+	}
+      if (taken_edge->probability > REG_BR_PROB_BASE)
+	taken_edge->probability = REG_BR_PROB_BASE;
+    }
+  else
+    taken_edge = single_succ_edge (bb);
+
+  bsi_remove (&bsi);
+  taken_edge->flags = EDGE_FALLTHRU;
+
+  /* We removed some paths from the cfg.  */
+  free_dominance_info (CDI_DOMINATORS);
+
+  return retval;
+}
+
+/* A list of all the noreturn calls passed to modify_stmt.
+   cleanup_control_flow uses it to detect cases where a mid-block
+   indirect call has been turned into a noreturn call.  When this
+   happens, all the instructions after the call are no longer
+   reachable and must be deleted as dead.  */
+
+VEC(tree,gc) *modified_noreturn_calls;
+
+/* Try to remove superfluous control structures.  */
+
+static bool
+cleanup_control_flow (void)
+{
+  basic_block bb;
+  block_stmt_iterator bsi;
+  bool retval = false;
+  tree stmt;
+
+  /* Detect cases where a mid-block call is now known not to return.  */
+  while (VEC_length (tree, modified_noreturn_calls))
+    {
+      stmt = VEC_pop (tree, modified_noreturn_calls);
+      bb = bb_for_stmt (stmt);
+      if (bb != NULL && last_stmt (bb) != stmt && noreturn_call_p (stmt))
+	split_block (bb, stmt);
+    }
+
+  FOR_EACH_BB (bb)
+    {
+      bsi = bsi_last (bb);
+
+      if (bsi_end_p (bsi))
+	continue;
+
+      stmt = bsi_stmt (bsi);
+      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.  */
+      if (TREE_CODE (stmt) == GOTO_EXPR
+	  && TREE_CODE (GOTO_DESTINATION (stmt)) == ADDR_EXPR
+	  && TREE_CODE (TREE_OPERAND (GOTO_DESTINATION (stmt), 0)) == LABEL_DECL)
+	{
+	  edge e;
+	  tree label;
+	  edge_iterator ei;
+	  basic_block target_block;
+	  bool removed_edge = false;
+
+	  /* 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);
+	  target_block = label_to_block (label);
+	  for (ei = ei_start (bb->succs); (e = ei_safe_edge (ei)); )
+	    {
+	      if (e->dest != target_block)
+		{
+		  removed_edge = true;
+		  remove_edge (e);
+		}
+	      else
+	        {
+		  /* Turn off the EDGE_ABNORMAL flag.  */
+		  e->flags &= ~EDGE_ABNORMAL;
+
+		  /* And set EDGE_FALLTHRU.  */
+		  e->flags |= EDGE_FALLTHRU;
+		  ei_next (&ei);
+		}
+	    }
+
+	  /* If we removed one or more edges, then we will need to fix the
+	     dominators.  It may be possible to incrementally update them.  */
+	  if (removed_edge)
+	    free_dominance_info (CDI_DOMINATORS);
+
+	  /* Remove the GOTO_EXPR as it is not needed.  The CFG has all the
+	     relevant information we need.  */
+	  bsi_remove (&bsi);
+	  retval = true;
+	}
+
+      /* Check for indirect calls that have been turned into
+	 noreturn calls.  */
+      if (noreturn_call_p (stmt) && remove_fallthru_edge (bb->succs))
+	{
+	  free_dominance_info (CDI_DOMINATORS);
+	  retval = true;
+	}
+    }
+  return retval;
+}
+
+/* Return true if basic block BB does nothing except pass control
+   flow to another block and that we can safely insert a label at
+   the start of the successor block.
+
+   As a precondition, we require that BB be not equal to
+   ENTRY_BLOCK_PTR.  */
+
+static bool
+tree_forwarder_block_p (basic_block bb, bool phi_wanted)
+{
+  block_stmt_iterator bsi;
+
+  /* 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
+      /* BB may not be a predecessor of EXIT_BLOCK_PTR.  */
+      || single_succ (bb) == EXIT_BLOCK_PTR
+      /* Nor should this be an infinite loop.  */
+      || single_succ (bb) == bb
+      /* BB may not have an abnormal outgoing edge.  */
+      || (single_succ_edge (bb)->flags & EDGE_ABNORMAL))
+    return false;
+
+#if ENABLE_CHECKING
+  gcc_assert (bb != ENTRY_BLOCK_PTR);
+#endif
+
+  /* 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))
+    {
+      tree stmt = bsi_stmt (bsi);
+
+      switch (TREE_CODE (stmt))
+	{
+	case LABEL_EXPR:
+	  if (DECL_NONLOCAL (LABEL_EXPR_LABEL (stmt)))
+	    return false;
+	  break;
+
+	default:
+	  return false;
+	}
+    }
+
+  if (find_edge (ENTRY_BLOCK_PTR, bb))
+    return false;
+
+  if (current_loops)
+    {
+      basic_block dest;
+      /* Protect loop latches, headers and preheaders.  */
+      if (bb->loop_father->header == bb)
+	return false;
+      dest = EDGE_SUCC (bb, 0)->dest;
+
+      if (dest->loop_father->header == dest)
+	return false;
+    }
+
+  return true;
+}
+
+/* Return true if BB has at least one abnormal incoming edge.  */
+
+static inline bool
+has_abnormal_incoming_edge_p (basic_block bb)
+{
+  edge e;
+  edge_iterator ei;
+
+  FOR_EACH_EDGE (e, ei, bb->preds)
+    if (e->flags & EDGE_ABNORMAL)
+      return true;
+
+  return false;
+}
+
+/* If all the PHI nodes in DEST have alternatives for E1 and E2 and
+   those alternatives are equal in each of the PHI nodes, then return
+   true, else return false.  */
+
+static bool
+phi_alternatives_equal (basic_block dest, edge e1, edge e2)
+{
+  int n1 = e1->dest_idx;
+  int n2 = e2->dest_idx;
+  tree phi;
+
+  for (phi = phi_nodes (dest); phi; phi = PHI_CHAIN (phi))
+    {
+      tree val1 = PHI_ARG_DEF (phi, n1);
+      tree val2 = PHI_ARG_DEF (phi, n2);
+
+      gcc_assert (val1 != NULL_TREE);
+      gcc_assert (val2 != NULL_TREE);
+
+      if (!operand_equal_for_phi_arg_p (val1, val2))
+	return false;
+    }
+
+  return true;
+}
+
+/* Removes forwarder block BB.  Returns false if this failed.  If a new
+   forwarder block is created due to redirection of edges, it is
+   stored to worklist.  */
+
+static bool
+remove_forwarder_block (basic_block bb, basic_block **worklist)
+{
+  edge succ = single_succ_edge (bb), e, s;
+  basic_block dest = succ->dest;
+  tree label;
+  tree phi;
+  edge_iterator ei;
+  block_stmt_iterator bsi, bsi_to;
+  bool seen_abnormal_edge = false;
+
+  /* We check for infinite loops already in tree_forwarder_block_p.
+     However it may happen that the infinite loop is created
+     afterwards due to removal of forwarders.  */
+  if (dest == bb)
+    return false;
+
+  /* If the destination block consists of a nonlocal label, do not merge
+     it.  */
+  label = first_stmt (dest);
+  if (label
+      && TREE_CODE (label) == LABEL_EXPR
+      && DECL_NONLOCAL (LABEL_EXPR_LABEL (label)))
+    return false;
+
+  /* If there is an abnormal edge to basic block BB, but not into
+     dest, problems might occur during removal of the phi node at out
+     of ssa due to overlapping live ranges of registers.
+
+     If there is an abnormal edge in DEST, the problems would occur
+     anyway since cleanup_dead_labels would then merge the labels for
+     two different eh regions, and rest of exception handling code
+     does not like it.
+
+     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 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))
+    {
+      FOR_EACH_EDGE (e, ei, bb->preds)
+	{
+	  s = find_edge (e->src, dest);
+	  if (!s)
+	    continue;
+
+	  if (!phi_alternatives_equal (dest, succ, s))
+	    return false;
+	}
+    }
+
+  /* Redirect the edges.  */
+  for (ei = ei_start (bb->preds); (e = ei_safe_edge (ei)); )
+    {
+      if (e->flags & EDGE_ABNORMAL)
+	{
+	  /* If there is an abnormal edge, redirect it anyway, and
+	     move the labels to the new block to make it legal.  */
+	  s = redirect_edge_succ_nodup (e, dest);
+	}
+      else
+	s = redirect_edge_and_branch (e, dest);
+
+      if (s == e)
+	{
+	  /* 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);
+	}
+      else
+	{
+	  /* The source basic block might become a forwarder.  We know
+	     that it was not a forwarder before, since it used to have
+	     at least two outgoing edges, so we may just add it to
+	     worklist.  */
+	  if (tree_forwarder_block_p (s->src, false))
+	    *(*worklist)++ = s->src;
+	}
+    }
+
+  if (seen_abnormal_edge)
+    {
+      /* Move the labels to the new block, so that the redirection of
+	 the abnormal edges works.  */
+
+      bsi_to = bsi_start (dest);
+      for (bsi = bsi_start (bb); !bsi_end_p (bsi); )
+	{
+	  label = bsi_stmt (bsi);
+	  gcc_assert (TREE_CODE (label) == LABEL_EXPR);
+	  bsi_remove (&bsi);
+	  bsi_insert_before (&bsi_to, label, BSI_CONTINUE_LINKING);
+	}
+    }
+
+  /* Update the dominators.  */
+  if (dom_info_available_p (CDI_DOMINATORS))
+    {
+      basic_block dom, dombb, domdest;
+
+      dombb = get_immediate_dominator (CDI_DOMINATORS, bb);
+      domdest = get_immediate_dominator (CDI_DOMINATORS, dest);
+      if (domdest == bb)
+	{
+	  /* Shortcut to avoid calling (relatively expensive)
+	     nearest_common_dominator unless necessary.  */
+	  dom = dombb;
+	}
+      else
+	dom = nearest_common_dominator (CDI_DOMINATORS, domdest, dombb);
+
+      set_immediate_dominator (CDI_DOMINATORS, dest, dom);
+    }
+
+  /* And kill the forwarder block.  */
+  delete_basic_block (bb);
+
+  return true;
+}
+
+/* Removes forwarder blocks.  */
+
+static bool
+cleanup_forwarder_blocks (void)
+{
+  basic_block bb;
+  bool changed = false;
+  basic_block *worklist = xmalloc (sizeof (basic_block) * n_basic_blocks);
+  basic_block *current = worklist;
+
+  FOR_EACH_BB (bb)
+    {
+      if (tree_forwarder_block_p (bb, false))
+	*current++ = bb;
+    }
+
+  while (current != worklist)
+    {
+      bb = *--current;
+      changed |= remove_forwarder_block (bb, &current);
+    }
+
+  free (worklist);
+  return changed;
+}
+
+/* Remove unreachable blocks and other miscellaneous clean up work.  */
+
+bool
+cleanup_tree_cfg (void)
+{
+  bool retval = false;
+
+  timevar_push (TV_TREE_CLEANUP_CFG);
+
+  retval = cleanup_control_flow ();
+  retval |= delete_unreachable_blocks ();
+
+  /* cleanup_forwarder_blocks can redirect edges out of SWITCH_EXPRs,
+     which can get expensive.  So we want to enable recording of edge
+     to CASE_LABEL_EXPR mappings around the call to
+     cleanup_forwarder_blocks.  */
+  start_recording_case_labels ();
+  retval |= cleanup_forwarder_blocks ();
+  end_recording_case_labels ();
+
+#ifdef ENABLE_CHECKING
+  if (retval)
+    {
+      gcc_assert (!cleanup_control_flow ());
+      gcc_assert (!delete_unreachable_blocks ());
+      gcc_assert (!cleanup_forwarder_blocks ());
+    }
+#endif
+
+  /* Merging the blocks creates no new opportunities for the other
+     optimizations, so do it here.  */
+  retval |= merge_seq_blocks ();
+
+  compact_blocks ();
+
+#ifdef ENABLE_CHECKING
+  verify_flow_info ();
+#endif
+  timevar_pop (TV_TREE_CLEANUP_CFG);
+  return retval;
+}
+
+/* Cleanup cfg and repair loop structures.  */
+
+void
+cleanup_tree_cfg_loop (void)
+{
+  bitmap changed_bbs = BITMAP_ALLOC (NULL);
+
+  cleanup_tree_cfg ();
+
+  fix_loop_structure (current_loops, changed_bbs);
+  calculate_dominance_info (CDI_DOMINATORS);
+
+  /* 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).  */
+  rewrite_into_loop_closed_ssa (changed_bbs, TODO_update_ssa);
+
+  BITMAP_FREE (changed_bbs);
+
+#ifdef ENABLE_CHECKING
+  verify_loop_structure (current_loops);
+#endif
+}
+
+/* Merge the PHI nodes at BB into those at BB's sole successor.  */
+
+static void
+remove_forwarder_block_with_phi (basic_block bb)
+{
+  edge succ = single_succ_edge (bb);
+  basic_block dest = succ->dest;
+  tree label;
+  basic_block dombb, domdest, dom;
+
+  /* We check for infinite loops already in tree_forwarder_block_p.
+     However it may happen that the infinite loop is created
+     afterwards due to removal of forwarders.  */
+  if (dest == bb)
+    return;
+
+  /* If the destination block consists of a nonlocal label, do not
+     merge it.  */
+  label = first_stmt (dest);
+  if (label
+      && TREE_CODE (label) == LABEL_EXPR
+      && DECL_NONLOCAL (LABEL_EXPR_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;
+
+      s = find_edge (e->src, dest);
+      if (s)
+	{
+	  /* We already have an edge S from E->src to DEST.  If S and
+	     E->dest's sole successor edge have the same PHI arguments
+	     at DEST, redirect S to DEST.  */
+	  if (phi_alternatives_equal (dest, s, succ))
+	    {
+	      e = redirect_edge_and_branch (e, dest);
+	      PENDING_STMT (e) = NULL_TREE;
+	      continue;
+	    }
+
+	  /* PHI arguments are different.  Create a forwarder block by
+	     splitting E so that we can merge PHI arguments on E to
+	     DEST.  */
+	  e = single_succ_edge (split_edge (e));
+	}
+
+      s = redirect_edge_and_branch (e, dest);
+
+      /* redirect_edge_and_branch must not create a new edge.  */
+      gcc_assert (s == e);
+
+      /* 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))
+	{
+	  tree def = PHI_ARG_DEF (phi, succ->dest_idx);
+
+	  if (TREE_CODE (def) == SSA_NAME)
+	    {
+	      tree var;
+
+	      /* 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))
+		{
+		  tree old_arg = TREE_PURPOSE (var);
+		  tree new_arg = TREE_VALUE (var);
+
+		  if (def == old_arg)
+		    {
+		      def = new_arg;
+		      break;
+		    }
+		}
+	    }
+
+	  add_phi_arg (phi, def, s);
+	}
+
+      PENDING_STMT (e) = NULL;
+    }
+
+  /* Update the dominators.  */
+  dombb = get_immediate_dominator (CDI_DOMINATORS, bb);
+  domdest = get_immediate_dominator (CDI_DOMINATORS, dest);
+  if (domdest == bb)
+    {
+      /* Shortcut to avoid calling (relatively expensive)
+	 nearest_common_dominator unless necessary.  */
+      dom = dombb;
+    }
+  else
+    dom = nearest_common_dominator (CDI_DOMINATORS, domdest, dombb);
+
+  set_immediate_dominator (CDI_DOMINATORS, dest, dom);
+
+  /* Remove BB since all of BB's incoming edges have been redirected
+     to DEST.  */
+  delete_basic_block (bb);
+}
+
+/* This pass merges PHI nodes if one feeds into another.  For example,
+   suppose we have the following:
+
+  goto <bb 9> (<L9>);
+
+<L8>:;
+  tem_17 = foo ();
+
+  # tem_6 = PHI <tem_17(8), tem_23(7)>;
+<L9>:;
+
+  # tem_3 = PHI <tem_6(9), tem_2(5)>;
+<L10>:;
+
+  Then we merge the first PHI node into the second one like so:
+
+  goto <bb 9> (<L10>);
+
+<L8>:;
+  tem_17 = foo ();
+
+  # tem_3 = PHI <tem_23(7), tem_2(5), tem_17(8)>;
+<L10>:;
+*/
+
+static void
+merge_phi_nodes (void)
+{
+  basic_block *worklist = xmalloc (sizeof (basic_block) * n_basic_blocks);
+  basic_block *current = worklist;
+  basic_block bb;
+
+  calculate_dominance_info (CDI_DOMINATORS);
+
+  /* Find all PHI nodes that we may be able to merge.  */
+  FOR_EACH_BB (bb)
+    {
+      basic_block dest;
+
+      /* Look for a forwarder block with PHI nodes.  */
+      if (!tree_forwarder_block_p (bb, true))
+	continue;
+
+      dest = single_succ (bb);
+
+      /* We have to feed into another basic block with PHI
+	 nodes.  */
+      if (!phi_nodes (dest)
+	  /* We don't want to deal with a basic block with
+	     abnormal edges.  */
+	  || has_abnormal_incoming_edge_p (bb))
+	continue;
+
+      if (!dominated_by_p (CDI_DOMINATORS, dest, bb))
+	{
+	  /* If BB does not dominate DEST, then the PHI nodes at
+	     DEST must be the only users of the results of the PHI
+	     nodes at BB.  */
+	  *current++ = bb;
+	}
+    }
+
+  /* Now let's drain WORKLIST.  */
+  while (current != worklist)
+    {
+      bb = *--current;
+      remove_forwarder_block_with_phi (bb);
+    }
+
+  free (worklist);
+}
+
+static bool
+gate_merge_phi (void)
+{
+  return 1;
+}
+
+struct tree_opt_pass pass_merge_phi = {
+  "mergephi",			/* name */
+  gate_merge_phi,		/* gate */
+  merge_phi_nodes,		/* execute */
+  NULL,				/* sub */
+  NULL,				/* next */
+  0,				/* static_pass_number */
+  TV_TREE_MERGE_PHI,		/* tv_id */
+  PROP_cfg | PROP_ssa,		/* 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 */
+};