--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/gcc/tree-outof-ssa.c	Fri Jul 17 14:47:48 2009 +0900
@@ -0,0 +1,1539 @@
+/* Convert a program in SSA form into Normal form.
+   Copyright (C) 2004, 2005, 2006, 2007, 2008 Free Software Foundation, Inc.
+   Contributed by Andrew Macleod <amacleod@redhat.com>
+
+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 3, 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 COPYING3.  If not see
+<http://www.gnu.org/licenses/>.  */
+
+#include "config.h"
+#include "system.h"
+#include "coretypes.h"
+#include "tm.h"
+#include "tree.h"
+#include "ggc.h"
+#include "basic-block.h"
+#include "diagnostic.h"
+#include "bitmap.h"
+#include "tree-flow.h"
+#include "timevar.h"
+#include "tree-dump.h"
+#include "tree-ssa-live.h"
+#include "tree-pass.h"
+#include "toplev.h"
+
+
+/* Used to hold all the components required to do SSA PHI elimination.
+   The node and pred/succ list is a simple linear list of nodes and
+   edges represented as pairs of nodes.
+
+   The predecessor and successor list:  Nodes are entered in pairs, where
+   [0] ->PRED, [1]->SUCC.  All the even indexes in the array represent 
+   predecessors, all the odd elements are successors. 
+   
+   Rationale:
+   When implemented as bitmaps, very large programs SSA->Normal times were 
+   being dominated by clearing the interference graph.
+
+   Typically this list of edges is extremely small since it only includes 
+   PHI results and uses from a single edge which have not coalesced with 
+   each other.  This means that no virtual PHI nodes are included, and
+   empirical evidence suggests that the number of edges rarely exceed
+   3, and in a bootstrap of GCC, the maximum size encountered was 7.
+   This also limits the number of possible nodes that are involved to
+   rarely more than 6, and in the bootstrap of gcc, the maximum number
+   of nodes encountered was 12.  */
+ 
+typedef struct _elim_graph {
+  /* Size of the elimination vectors.  */
+  int size;
+
+  /* List of nodes in the elimination graph.  */
+  VEC(tree,heap) *nodes;
+
+  /*  The predecessor and successor edge list.  */
+  VEC(int,heap) *edge_list;
+
+  /* Visited vector.  */
+  sbitmap visited;
+
+  /* Stack for visited nodes.  */
+  VEC(int,heap) *stack;
+  
+  /* The variable partition map.  */
+  var_map map;
+
+  /* Edge being eliminated by this graph.  */
+  edge e;
+
+  /* List of constant copies to emit.  These are pushed on in pairs.  */
+  VEC(tree,heap) *const_copies;
+} *elim_graph;
+
+
+/* Create a temporary variable based on the type of variable T.  Use T's name
+   as the prefix.  */
+
+static tree
+create_temp (tree t)
+{
+  tree tmp;
+  const char *name = NULL;
+  tree type;
+
+  if (TREE_CODE (t) == SSA_NAME)
+    t = SSA_NAME_VAR (t);
+
+  gcc_assert (TREE_CODE (t) == VAR_DECL || TREE_CODE (t) == PARM_DECL);
+
+  type = TREE_TYPE (t);
+  tmp = DECL_NAME (t);
+  if (tmp)
+    name = IDENTIFIER_POINTER (tmp);
+
+  if (name == NULL)
+    name = "temp";
+  tmp = create_tmp_var (type, name);
+
+  if (DECL_DEBUG_EXPR_IS_FROM (t) && DECL_DEBUG_EXPR (t))
+    {
+      SET_DECL_DEBUG_EXPR (tmp, DECL_DEBUG_EXPR (t));  
+      DECL_DEBUG_EXPR_IS_FROM (tmp) = 1;
+    }
+  else if (!DECL_IGNORED_P (t))
+    {
+      SET_DECL_DEBUG_EXPR (tmp, t);
+      DECL_DEBUG_EXPR_IS_FROM (tmp) = 1;
+    }
+  DECL_ARTIFICIAL (tmp) = DECL_ARTIFICIAL (t);
+  DECL_IGNORED_P (tmp) = DECL_IGNORED_P (t);
+  DECL_GIMPLE_REG_P (tmp) = DECL_GIMPLE_REG_P (t);
+  add_referenced_var (tmp);
+
+  /* add_referenced_var will create the annotation and set up some
+     of the flags in the annotation.  However, some flags we need to
+     inherit from our original variable.  */
+  set_symbol_mem_tag (tmp, symbol_mem_tag (t));
+  if (is_call_clobbered (t))
+    mark_call_clobbered (tmp, var_ann (t)->escape_mask);
+  if (bitmap_bit_p (gimple_call_used_vars (cfun), DECL_UID (t)))
+    bitmap_set_bit (gimple_call_used_vars (cfun), DECL_UID (tmp));
+
+  return tmp;
+}
+
+
+/* This helper function fill insert a copy from a constant or variable SRC to 
+   variable DEST on edge E.  */
+
+static void
+insert_copy_on_edge (edge e, tree dest, tree src)
+{
+  gimple copy;
+
+  copy = gimple_build_assign (dest, src);
+  set_is_used (dest);
+
+  if (TREE_CODE (src) == ADDR_EXPR)
+    src = TREE_OPERAND (src, 0);
+  if (TREE_CODE (src) == VAR_DECL || TREE_CODE (src) == PARM_DECL)
+    set_is_used (src);
+
+  if (dump_file && (dump_flags & TDF_DETAILS))
+    {
+      fprintf (dump_file,
+	       "Inserting a copy on edge BB%d->BB%d :",
+	       e->src->index,
+	       e->dest->index);
+      print_gimple_stmt (dump_file, copy, 0, dump_flags);
+      fprintf (dump_file, "\n");
+    }
+
+  gsi_insert_on_edge (e, copy);
+}
+
+
+/* Create an elimination graph with SIZE nodes and associated data
+   structures.  */
+
+static elim_graph
+new_elim_graph (int size)
+{
+  elim_graph g = (elim_graph) xmalloc (sizeof (struct _elim_graph));
+
+  g->nodes = VEC_alloc (tree, heap, 30);
+  g->const_copies = VEC_alloc (tree, heap, 20);
+  g->edge_list = VEC_alloc (int, heap, 20);
+  g->stack = VEC_alloc (int, heap, 30);
+  
+  g->visited = sbitmap_alloc (size);
+
+  return g;
+}
+
+
+/* Empty elimination graph G.  */
+
+static inline void
+clear_elim_graph (elim_graph g)
+{
+  VEC_truncate (tree, g->nodes, 0);
+  VEC_truncate (int, g->edge_list, 0);
+}
+
+
+/* Delete elimination graph G.  */
+
+static inline void
+delete_elim_graph (elim_graph g)
+{
+  sbitmap_free (g->visited);
+  VEC_free (int, heap, g->stack);
+  VEC_free (int, heap, g->edge_list);
+  VEC_free (tree, heap, g->const_copies);
+  VEC_free (tree, heap, g->nodes);
+  free (g);
+}
+
+
+/* Return the number of nodes in graph G.  */
+
+static inline int
+elim_graph_size (elim_graph g)
+{
+  return VEC_length (tree, g->nodes);
+}
+
+
+/* Add NODE to graph G, if it doesn't exist already.  */
+
+static inline void 
+elim_graph_add_node (elim_graph g, tree node)
+{
+  int x;
+  tree t;
+
+  for (x = 0; VEC_iterate (tree, g->nodes, x, t); x++)
+    if (t == node)
+      return;
+  VEC_safe_push (tree, heap, g->nodes, node);
+}
+
+
+/* Add the edge PRED->SUCC to graph G.  */
+
+static inline void
+elim_graph_add_edge (elim_graph g, int pred, int succ)
+{
+  VEC_safe_push (int, heap, g->edge_list, pred);
+  VEC_safe_push (int, heap, g->edge_list, succ);
+}
+
+
+/* Remove an edge from graph G for which NODE is the predecessor, and
+   return the successor node.  -1 is returned if there is no such edge.  */
+
+static inline int
+elim_graph_remove_succ_edge (elim_graph g, int node)
+{
+  int y;
+  unsigned x;
+  for (x = 0; x < VEC_length (int, g->edge_list); x += 2)
+    if (VEC_index (int, g->edge_list, x) == node)
+      {
+        VEC_replace (int, g->edge_list, x, -1);
+	y = VEC_index (int, g->edge_list, x + 1);
+	VEC_replace (int, g->edge_list, x + 1, -1);
+	return y;
+      }
+  return -1;
+}
+
+
+/* Find all the nodes in GRAPH which are successors to NODE in the
+   edge list.  VAR will hold the partition number found.  CODE is the
+   code fragment executed for every node found.  */
+
+#define FOR_EACH_ELIM_GRAPH_SUCC(GRAPH, NODE, VAR, CODE)		\
+do {									\
+  unsigned x_;								\
+  int y_;								\
+  for (x_ = 0; x_ < VEC_length (int, (GRAPH)->edge_list); x_ += 2)	\
+    {									\
+      y_ = VEC_index (int, (GRAPH)->edge_list, x_);			\
+      if (y_ != (NODE))							\
+        continue;							\
+      (VAR) = VEC_index (int, (GRAPH)->edge_list, x_ + 1);		\
+      CODE;								\
+    }									\
+} while (0)
+
+
+/* Find all the nodes which are predecessors of NODE in the edge list for
+   GRAPH.  VAR will hold the partition number found.  CODE is the
+   code fragment executed for every node found.  */
+
+#define FOR_EACH_ELIM_GRAPH_PRED(GRAPH, NODE, VAR, CODE)		\
+do {									\
+  unsigned x_;								\
+  int y_;								\
+  for (x_ = 0; x_ < VEC_length (int, (GRAPH)->edge_list); x_ += 2)	\
+    {									\
+      y_ = VEC_index (int, (GRAPH)->edge_list, x_ + 1);			\
+      if (y_ != (NODE))							\
+        continue;							\
+      (VAR) = VEC_index (int, (GRAPH)->edge_list, x_);			\
+      CODE;								\
+    }									\
+} while (0)
+
+
+/* Add T to elimination graph G.  */
+
+static inline void
+eliminate_name (elim_graph g, tree T)
+{
+  elim_graph_add_node (g, T);
+}
+
+
+/* Build elimination graph G for basic block BB on incoming PHI edge
+   G->e.  */
+
+static void
+eliminate_build (elim_graph g, basic_block B)
+{
+  tree T0, Ti;
+  int p0, pi;
+  gimple_stmt_iterator gsi;
+
+  clear_elim_graph (g);
+  
+  for (gsi = gsi_start_phis (B); !gsi_end_p (gsi); gsi_next (&gsi))
+    {
+      gimple phi = gsi_stmt (gsi);
+
+      T0 = var_to_partition_to_var (g->map, gimple_phi_result (phi));
+      
+      /* Ignore results which are not in partitions.  */
+      if (T0 == NULL_TREE)
+	continue;
+
+      Ti = PHI_ARG_DEF (phi, g->e->dest_idx);
+
+      /* If this argument is a constant, or a SSA_NAME which is being
+	 left in SSA form, just queue a copy to be emitted on this
+	 edge.  */
+      if (!phi_ssa_name_p (Ti)
+	  || (TREE_CODE (Ti) == SSA_NAME
+	      && var_to_partition (g->map, Ti) == NO_PARTITION))
+        {
+	  /* Save constant copies until all other copies have been emitted
+	     on this edge.  */
+	  VEC_safe_push (tree, heap, g->const_copies, T0);
+	  VEC_safe_push (tree, heap, g->const_copies, Ti);
+	}
+      else
+        {
+	  Ti = var_to_partition_to_var (g->map, Ti);
+	  if (T0 != Ti)
+	    {
+	      eliminate_name (g, T0);
+	      eliminate_name (g, Ti);
+	      p0 = var_to_partition (g->map, T0);
+	      pi = var_to_partition (g->map, Ti);
+	      elim_graph_add_edge (g, p0, pi);
+	    }
+	}
+    }
+}
+
+
+/* Push successors of T onto the elimination stack for G.  */
+
+static void 
+elim_forward (elim_graph g, int T)
+{
+  int S;
+  SET_BIT (g->visited, T);
+  FOR_EACH_ELIM_GRAPH_SUCC (g, T, S,
+    {
+      if (!TEST_BIT (g->visited, S))
+        elim_forward (g, S);
+    });
+  VEC_safe_push (int, heap, g->stack, T);
+}
+
+
+/* Return 1 if there unvisited predecessors of T in graph G.  */
+
+static int
+elim_unvisited_predecessor (elim_graph g, int T)
+{
+  int P;
+  FOR_EACH_ELIM_GRAPH_PRED (g, T, P, 
+    {
+      if (!TEST_BIT (g->visited, P))
+        return 1;
+    });
+  return 0;
+}
+
+/* Process predecessors first, and insert a copy.  */
+
+static void
+elim_backward (elim_graph g, int T)
+{
+  int P;
+  SET_BIT (g->visited, T);
+  FOR_EACH_ELIM_GRAPH_PRED (g, T, P, 
+    {
+      if (!TEST_BIT (g->visited, P))
+        {
+	  elim_backward (g, P);
+	  insert_copy_on_edge (g->e, 
+			       partition_to_var (g->map, P), 
+			       partition_to_var (g->map, T));
+	}
+    });
+}
+
+/* Insert required copies for T in graph G.  Check for a strongly connected 
+   region, and create a temporary to break the cycle if one is found.  */
+
+static void 
+elim_create (elim_graph g, int T)
+{
+  tree U;
+  int P, S;
+
+  if (elim_unvisited_predecessor (g, T))
+    {
+      U = create_temp (partition_to_var (g->map, T));
+      insert_copy_on_edge (g->e, U, partition_to_var (g->map, T));
+      FOR_EACH_ELIM_GRAPH_PRED (g, T, P, 
+	{
+	  if (!TEST_BIT (g->visited, P))
+	    {
+	      elim_backward (g, P);
+	      insert_copy_on_edge (g->e, partition_to_var (g->map, P), U);
+	    }
+	});
+    }
+  else
+    {
+      S = elim_graph_remove_succ_edge (g, T);
+      if (S != -1)
+	{
+	  SET_BIT (g->visited, T);
+	  insert_copy_on_edge (g->e, 
+			       partition_to_var (g->map, T), 
+			       partition_to_var (g->map, S));
+	}
+    }
+  
+}
+
+
+/* Eliminate all the phi nodes on edge E in graph G.  */
+
+static void
+eliminate_phi (edge e, elim_graph g)
+{
+  int x;
+  basic_block B = e->dest;
+
+  gcc_assert (VEC_length (tree, g->const_copies) == 0);
+
+  /* Abnormal edges already have everything coalesced.  */
+  if (e->flags & EDGE_ABNORMAL)
+    return;
+
+  g->e = e;
+
+  eliminate_build (g, B);
+
+  if (elim_graph_size (g) != 0)
+    {
+      tree var;
+
+      sbitmap_zero (g->visited);
+      VEC_truncate (int, g->stack, 0);
+
+      for (x = 0; VEC_iterate (tree, g->nodes, x, var); x++)
+        {
+	  int p = var_to_partition (g->map, var);
+	  if (!TEST_BIT (g->visited, p))
+	    elim_forward (g, p);
+	}
+       
+      sbitmap_zero (g->visited);
+      while (VEC_length (int, g->stack) > 0)
+	{
+	  x = VEC_pop (int, g->stack);
+	  if (!TEST_BIT (g->visited, x))
+	    elim_create (g, x);
+	}
+    }
+
+  /* If there are any pending constant copies, issue them now.  */
+  while (VEC_length (tree, g->const_copies) > 0)
+    {
+      tree src, dest;
+      src = VEC_pop (tree, g->const_copies);
+      dest = VEC_pop (tree, g->const_copies);
+      insert_copy_on_edge (e, dest, src);
+    }
+}
+
+
+/* Take the ssa-name var_map MAP, and assign real variables to each 
+   partition.  */
+
+static void
+assign_vars (var_map map)
+{
+  int x, num;
+  tree var, root;
+  var_ann_t ann;
+
+  num = num_var_partitions (map);
+  for (x = 0; x < num; x++)
+    {
+      var = partition_to_var (map, x);
+      if (TREE_CODE (var) != SSA_NAME)
+	{
+	  ann = var_ann (var);
+	  /* It must already be coalesced.  */
+	  gcc_assert (ann->out_of_ssa_tag == 1);
+	  if (dump_file && (dump_flags & TDF_DETAILS))
+	    {
+	      fprintf (dump_file, "partition %d already has variable ", x);
+	      print_generic_expr (dump_file, var, TDF_SLIM);
+	      fprintf (dump_file, " assigned to it.\n");
+	    }
+	}
+      else
+        {
+	  root = SSA_NAME_VAR (var);
+	  ann = var_ann (root);
+	  /* If ROOT is already associated, create a new one.  */
+	  if (ann->out_of_ssa_tag)
+	    {
+	      root = create_temp (root);
+	      ann = var_ann (root);
+	    }
+	  /* ROOT has not been coalesced yet, so use it.  */
+	  if (dump_file && (dump_flags & TDF_DETAILS))
+	    {
+	      fprintf (dump_file, "Partition %d is assigned to var ", x);
+	      print_generic_stmt (dump_file, root, TDF_SLIM);
+	    }
+	  change_partition_var (map, root, x);
+	}
+    }
+}
+
+
+/* Replace use operand P with whatever variable it has been rewritten to based 
+   on the partitions in MAP.  EXPR is an optional expression vector over SSA 
+   versions which is used to replace P with an expression instead of a variable.
+   If the stmt is changed, return true.  */ 
+
+static inline bool
+replace_use_variable (var_map map, use_operand_p p, gimple *expr)
+{
+  tree new_var;
+  tree var = USE_FROM_PTR (p);
+
+  /* Check if we are replacing this variable with an expression.  */
+  if (expr)
+    {
+      int version = SSA_NAME_VERSION (var);
+      if (expr[version])
+        {
+	  SET_USE (p, gimple_assign_rhs_to_tree (expr[version]));
+	  return true;
+	}
+    }
+
+  new_var = var_to_partition_to_var (map, var);
+  if (new_var)
+    {
+      SET_USE (p, new_var);
+      set_is_used (new_var);
+      return true;
+    }
+  return false;
+}
+
+
+/* Replace def operand DEF_P with whatever variable it has been rewritten to 
+   based on the partitions in MAP.  EXPR is an optional expression vector over
+   SSA versions which is used to replace DEF_P with an expression instead of a 
+   variable.  If the stmt is changed, return true.  */ 
+
+static inline bool
+replace_def_variable (var_map map, def_operand_p def_p, tree *expr)
+{
+  tree new_var;
+  tree var = DEF_FROM_PTR (def_p);
+
+  /* Do nothing if we are replacing this variable with an expression.  */
+  if (expr && expr[SSA_NAME_VERSION (var)])
+    return true;
+
+  new_var = var_to_partition_to_var (map, var);
+  if (new_var)
+    {
+      SET_DEF (def_p, new_var);
+      set_is_used (new_var);
+      return true;
+    }
+  return false;
+}
+
+
+/* Remove each argument from PHI.  If an arg was the last use of an SSA_NAME, 
+   check to see if this allows another PHI node to be removed.  */
+
+static void
+remove_gimple_phi_args (gimple phi)
+{
+  use_operand_p arg_p;
+  ssa_op_iter iter;
+
+  if (dump_file && (dump_flags & TDF_DETAILS))
+    {
+      fprintf (dump_file, "Removing Dead PHI definition: ");
+      print_gimple_stmt (dump_file, phi, 0, TDF_SLIM);
+    }
+
+  FOR_EACH_PHI_ARG (arg_p, phi, iter, SSA_OP_USE)
+    {
+      tree arg = USE_FROM_PTR (arg_p);
+      if (TREE_CODE (arg) == SSA_NAME)
+        {
+	  /* Remove the reference to the existing argument.  */
+	  SET_USE (arg_p, NULL_TREE);
+	  if (has_zero_uses (arg))
+	    {
+	      gimple stmt;
+	      gimple_stmt_iterator gsi;
+
+	      stmt = SSA_NAME_DEF_STMT (arg);
+
+	      /* Also remove the def if it is a PHI node.  */
+	      if (gimple_code (stmt) == GIMPLE_PHI)
+		{
+		  remove_gimple_phi_args (stmt);
+		  gsi = gsi_for_stmt (stmt);
+		  remove_phi_node (&gsi, true);
+		}
+
+	    }
+	}
+    }
+}
+
+/* Remove any PHI node which is a virtual PHI, or a PHI with no uses.  */
+
+static void
+eliminate_useless_phis (void)
+{
+  basic_block bb;
+  gimple_stmt_iterator gsi;
+  tree result;
+
+  FOR_EACH_BB (bb)
+    {
+      for (gsi = gsi_start_phis (bb); !gsi_end_p (gsi); )
+        {
+	  gimple phi = gsi_stmt (gsi);
+	  result = gimple_phi_result (phi);
+	  if (!is_gimple_reg (SSA_NAME_VAR (result)))
+	    {
+#ifdef ENABLE_CHECKING
+	      size_t i;
+	      /* There should be no arguments which are not virtual, or the
+	         results will be incorrect.  */
+	      for (i = 0; i < gimple_phi_num_args (phi); i++)
+	        {
+		  tree arg = PHI_ARG_DEF (phi, i);
+		  if (TREE_CODE (arg) == SSA_NAME 
+		      && is_gimple_reg (SSA_NAME_VAR (arg)))
+		    {
+		      fprintf (stderr, "Argument of PHI is not virtual (");
+		      print_generic_expr (stderr, arg, TDF_SLIM);
+		      fprintf (stderr, "), but the result is :");
+		      print_gimple_stmt (stderr, phi, 0, TDF_SLIM);
+		      internal_error ("SSA corruption");
+		    }
+		}
+#endif
+	      remove_phi_node (&gsi, true);
+	    }
+          else
+	    {
+	      /* Also remove real PHIs with no uses.  */
+	      if (has_zero_uses (result))
+	        {
+		  remove_gimple_phi_args (phi);
+		  remove_phi_node (&gsi, true);
+		}
+	      else
+		gsi_next (&gsi);
+	    }
+	}
+    }
+}
+
+
+/* This function will rewrite the current program using the variable mapping
+   found in MAP.  If the replacement vector VALUES is provided, any 
+   occurrences of partitions with non-null entries in the vector will be 
+   replaced with the expression in the vector instead of its mapped 
+   variable.  */
+
+static void
+rewrite_trees (var_map map, gimple *values)
+{
+  elim_graph g;
+  basic_block bb;
+  gimple_stmt_iterator gsi;
+  edge e;
+  gimple_seq phi;
+  bool changed;
+ 
+#ifdef ENABLE_CHECKING
+  /* Search for PHIs where the destination has no partition, but one
+     or more arguments has a partition.  This should not happen and can
+     create incorrect code.  */
+  FOR_EACH_BB (bb)
+    {
+      for (gsi = gsi_start_phis (bb); !gsi_end_p (gsi); gsi_next (&gsi))
+	{
+	  gimple phi = gsi_stmt (gsi);
+	  tree T0 = var_to_partition_to_var (map, gimple_phi_result (phi));
+	  if (T0 == NULL_TREE)
+	    {
+	      size_t i;
+	      for (i = 0; i < gimple_phi_num_args (phi); i++)
+		{
+		  tree arg = PHI_ARG_DEF (phi, i);
+
+		  if (TREE_CODE (arg) == SSA_NAME
+		      && var_to_partition (map, arg) != NO_PARTITION)
+		    {
+		      fprintf (stderr, "Argument of PHI is in a partition :(");
+		      print_generic_expr (stderr, arg, TDF_SLIM);
+		      fprintf (stderr, "), but the result is not :");
+		      print_gimple_stmt (stderr, phi, 0, TDF_SLIM);
+		      internal_error ("SSA corruption");
+		    }
+		}
+	    }
+	}
+    }
+#endif
+
+  /* Replace PHI nodes with any required copies.  */
+  g = new_elim_graph (map->num_partitions);
+  g->map = map;
+  FOR_EACH_BB (bb)
+    {
+      for (gsi = gsi_start_bb (bb); !gsi_end_p (gsi); )
+	{
+	  gimple stmt = gsi_stmt (gsi);
+	  use_operand_p use_p, copy_use_p;
+	  def_operand_p def_p;
+	  bool remove = false, is_copy = false;
+	  int num_uses = 0;
+	  ssa_op_iter iter;
+
+	  changed = false;
+
+	  if (gimple_assign_copy_p (stmt))
+	    is_copy = true;
+
+	  copy_use_p = NULL_USE_OPERAND_P;
+	  FOR_EACH_SSA_USE_OPERAND (use_p, stmt, iter, SSA_OP_USE)
+	    {
+	      if (replace_use_variable (map, use_p, values))
+		changed = true;
+	      copy_use_p = use_p;
+	      num_uses++;
+	    }
+
+	  if (num_uses != 1)
+	    is_copy = false;
+
+	  def_p = SINGLE_SSA_DEF_OPERAND (stmt, SSA_OP_DEF);
+
+	  if (def_p != NULL)
+	    {
+	      /* Mark this stmt for removal if it is the list of replaceable 
+		 expressions.  */
+	      if (values && values[SSA_NAME_VERSION (DEF_FROM_PTR (def_p))])
+		remove = true;
+	      else
+		{
+		  if (replace_def_variable (map, def_p, NULL))
+		    changed = true;
+		  /* If both SSA_NAMEs coalesce to the same variable,
+		     mark the now redundant copy for removal.  */
+		  if (is_copy)
+		    {
+		      gcc_assert (copy_use_p != NULL_USE_OPERAND_P);
+		      if (DEF_FROM_PTR (def_p) == USE_FROM_PTR (copy_use_p))
+			remove = true;
+		    }
+		}
+	    }
+	  else
+	    FOR_EACH_SSA_DEF_OPERAND (def_p, stmt, iter, SSA_OP_DEF)
+	      if (replace_def_variable (map, def_p, NULL))
+		changed = true;
+
+	  /* Remove any stmts marked for removal.  */
+	  if (remove)
+	    gsi_remove (&gsi, true);
+	  else
+	    {
+	      if (changed)
+		if (maybe_clean_or_replace_eh_stmt (stmt, stmt))
+		  gimple_purge_dead_eh_edges (bb);
+	      gsi_next (&gsi);
+	    }
+	}
+
+      phi = phi_nodes (bb);
+      if (phi)
+        {
+	  edge_iterator ei;
+	  FOR_EACH_EDGE (e, ei, bb->preds)
+	    eliminate_phi (e, g);
+	}
+    }
+
+  delete_elim_graph (g);
+}
+
+/* These are the local work structures used to determine the best place to 
+   insert the copies that were placed on edges by the SSA->normal pass..  */
+static VEC(edge,heap) *edge_leader;
+static VEC(gimple_seq,heap) *stmt_list;
+static bitmap leader_has_match = NULL;
+static edge leader_match = NULL;
+
+
+/* Pass this function to make_forwarder_block so that all the edges with
+   matching PENDING_STMT lists to 'curr_stmt_list' get redirected.  E is the
+   edge to test for a match.  */
+
+static inline bool 
+same_stmt_list_p (edge e)
+{
+  return (e->aux == (PTR) leader_match) ? true : false;
+}
+
+
+/* Return TRUE if S1 and S2 are equivalent copies.  */
+
+static inline bool
+identical_copies_p (const_gimple s1, const_gimple s2)
+{
+#ifdef ENABLE_CHECKING
+  gcc_assert (is_gimple_assign (s1));
+  gcc_assert (is_gimple_assign (s2));
+  gcc_assert (DECL_P (gimple_assign_lhs (s1)));
+  gcc_assert (DECL_P (gimple_assign_lhs (s2)));
+#endif
+
+  if (gimple_assign_lhs (s1) != gimple_assign_lhs (s2))
+    return false;
+
+  if (gimple_assign_rhs1 (s1) != gimple_assign_rhs1 (s2))
+    return false;
+
+  return true;
+}
+
+
+/* Compare the PENDING_STMT list for edges E1 and E2. Return true if the lists
+   contain the same sequence of copies.  */
+
+static inline bool 
+identical_stmt_lists_p (const_edge e1, const_edge e2)
+{
+  gimple_seq t1 = PENDING_STMT (e1);
+  gimple_seq t2 = PENDING_STMT (e2);
+  gimple_stmt_iterator gsi1, gsi2;
+
+  for (gsi1 = gsi_start (t1), gsi2 = gsi_start (t2);
+       !gsi_end_p (gsi1) && !gsi_end_p (gsi2); 
+       gsi_next (&gsi1), gsi_next (&gsi2))
+    {
+      if (!identical_copies_p (gsi_stmt (gsi1), gsi_stmt (gsi2)))
+        break;
+    }
+
+  if (!gsi_end_p (gsi1) || !gsi_end_p (gsi2))
+    return false;
+
+  return true;
+}
+
+
+/* Allocate data structures used in analyze_edges_for_bb.   */
+
+static void
+init_analyze_edges_for_bb (void)
+{
+  edge_leader = VEC_alloc (edge, heap, 25);
+  stmt_list = VEC_alloc (gimple_seq, heap, 25);
+  leader_has_match = BITMAP_ALLOC (NULL);
+}
+
+
+/* Free data structures used in analyze_edges_for_bb.   */
+
+static void
+fini_analyze_edges_for_bb (void)
+{
+  VEC_free (edge, heap, edge_leader);
+  VEC_free (gimple_seq, heap, stmt_list);
+  BITMAP_FREE (leader_has_match);
+}
+
+/* A helper function to be called via walk_tree.  Return DATA if it is
+  contained in subtree TP.  */
+ 
+static tree
+contains_tree_r (tree * tp, int *walk_subtrees, void *data)
+{
+  if (*tp == data)
+    {
+      *walk_subtrees = 0;
+      return (tree) data;
+    }
+  else
+    return NULL_TREE;
+}
+
+/* A threshold for the number of insns contained in the latch block.
+   It is used to prevent blowing the loop with too many copies from
+   the latch.  */
+#define MAX_STMTS_IN_LATCH 2
+
+/* Return TRUE if the stmts on SINGLE-EDGE can be moved to the
+   body of the loop.  This should be permitted only if SINGLE-EDGE is a
+   single-basic-block latch edge and thus cleaning the latch will help
+   to create a single-basic-block loop.  Otherwise return FALSE.  */
+
+static bool
+process_single_block_loop_latch (edge single_edge)
+{
+  gimple_seq stmts;
+  basic_block b_exit, b_pheader, b_loop = single_edge->src;
+  edge_iterator ei;
+  edge e;
+  gimple_stmt_iterator gsi, gsi_exit;
+  gimple_stmt_iterator tsi;
+  tree expr;
+  gimple stmt;
+  unsigned int count = 0;
+
+  if (single_edge == NULL || (single_edge->dest != single_edge->src)
+      || (EDGE_COUNT (b_loop->succs) != 2)
+      || (EDGE_COUNT (b_loop->preds) != 2))
+    return false;
+
+  /* Get the stmts on the latch edge.  */
+  stmts = PENDING_STMT (single_edge);
+
+  /* Find the successor edge which is not the latch edge.  */
+  FOR_EACH_EDGE (e, ei, b_loop->succs) 
+   if (e->dest != b_loop)
+    break;
+
+  b_exit = e->dest;
+
+  /* Check that the exit block has only the loop as a predecessor,
+     and that there are no pending stmts on that edge as well.   */
+  if (EDGE_COUNT (b_exit->preds) != 1 || PENDING_STMT (e))
+    return false;
+
+  /* Find the predecessor edge which is not the latch edge.  */
+  FOR_EACH_EDGE (e, ei, b_loop->preds) 
+   if (e->src != b_loop)
+    break;
+
+  b_pheader = e->src;
+
+  if (b_exit == b_pheader || b_exit == b_loop || b_pheader == b_loop)
+    return false;
+
+  gsi_exit = gsi_after_labels (b_exit);
+
+  /* Get the last stmt in the loop body.  */
+  gsi = gsi_last_bb (single_edge->src);
+  stmt = gsi_stmt (gsi);
+
+  if (gimple_code (stmt) != GIMPLE_COND)
+    return false;
+
+
+  expr = build2 (gimple_cond_code (stmt), boolean_type_node,
+                 gimple_cond_lhs (stmt), gimple_cond_rhs (stmt));
+  /* Iterate over the insns on the latch and count them.  */
+  for (tsi = gsi_start (stmts); !gsi_end_p (tsi); gsi_next (&tsi))
+    {
+      gimple stmt1 = gsi_stmt (tsi);
+      tree var;
+
+      count++;
+      /* Check that the condition does not contain any new definition
+         created in the latch as the stmts from the latch intended
+         to precede it.  */
+      if (gimple_code (stmt1) != GIMPLE_ASSIGN)
+        return false;
+      var = gimple_assign_lhs (stmt1);
+      if (TREE_THIS_VOLATILE (var)
+	  || TYPE_VOLATILE (TREE_TYPE (var))
+	  || walk_tree (&expr, contains_tree_r, var, NULL))
+	return false;
+    }
+  /* Check that the latch does not contain more than MAX_STMTS_IN_LATCH
+     insns.  The purpose of this restriction is to prevent blowing the
+     loop with too many copies from the latch.  */
+  if (count > MAX_STMTS_IN_LATCH)
+    return false;
+
+  /* Apply the transformation - clean up the latch block:  
+
+     var = something; 
+     L1:
+     x1 = expr;
+     if (cond) goto L2 else goto L3;
+     L2:
+     var = x1;
+     goto L1
+     L3:
+     ...
+
+     ==>
+
+     var = something;
+     L1:
+     x1 = expr;
+     tmp_var = var;
+     var = x1;
+     if (cond) goto L1 else goto L2;
+     L2:
+     var = tmp_var;
+     ... 
+   */
+  for (tsi = gsi_start (stmts); !gsi_end_p (tsi); gsi_next (&tsi))
+    {
+      gimple stmt1 = gsi_stmt (tsi);
+      tree var, tmp_var;
+      gimple copy;
+
+      /* Create a new variable to load back the value of var in case
+         we exit the loop.  */
+      var = gimple_assign_lhs (stmt1);
+      tmp_var = create_temp (var);
+      copy = gimple_build_assign (tmp_var, var);
+      set_is_used (tmp_var);
+      gsi_insert_before (&gsi, copy, GSI_SAME_STMT);
+      copy = gimple_build_assign (var, tmp_var);
+      gsi_insert_before (&gsi_exit, copy, GSI_SAME_STMT);
+    }
+
+  PENDING_STMT (single_edge) = 0;
+  /* Insert the new stmts to the loop body.  */
+  gsi_insert_seq_before (&gsi, stmts, GSI_NEW_STMT);
+
+  if (dump_file)
+    fprintf (dump_file,
+	     "\nCleaned-up latch block of loop with single BB: %d\n\n",
+	     single_edge->dest->index);
+
+  return true;
+}
+
+/* Look at all the incoming edges to block BB, and decide where the best place
+   to insert the stmts on each edge are, and perform those insertions.  */
+
+static void
+analyze_edges_for_bb (basic_block bb)
+{
+  edge e;
+  edge_iterator ei;
+  int count;
+  unsigned int x;
+  bool have_opportunity;
+  gimple_stmt_iterator gsi;
+  gimple stmt;
+  edge single_edge = NULL;
+  bool is_label;
+  edge leader;
+
+  count = 0;
+
+  /* Blocks which contain at least one abnormal edge cannot use 
+     make_forwarder_block.  Look for these blocks, and commit any PENDING_STMTs
+     found on edges in these block.  */
+  have_opportunity = true;
+  FOR_EACH_EDGE (e, ei, bb->preds)
+    if (e->flags & EDGE_ABNORMAL)
+      {
+        have_opportunity = false;
+	break;
+      }
+
+  if (!have_opportunity)
+    {
+      FOR_EACH_EDGE (e, ei, bb->preds)
+	if (PENDING_STMT (e))
+	  gsi_commit_one_edge_insert (e, NULL);
+      return;
+    }
+
+  /* Find out how many edges there are with interesting pending stmts on them.  
+     Commit the stmts on edges we are not interested in.  */
+  FOR_EACH_EDGE (e, ei, bb->preds)
+    {
+      if (PENDING_STMT (e))
+        {
+	  gcc_assert (!(e->flags & EDGE_ABNORMAL));
+	  if (e->flags & EDGE_FALLTHRU)
+	    {
+	      gsi = gsi_start_bb (e->src);
+	      if (!gsi_end_p (gsi))
+	        {
+		  stmt = gsi_stmt (gsi);
+		  gsi_next (&gsi);
+		  gcc_assert (stmt != NULL);
+		  is_label = (gimple_code (stmt) == GIMPLE_LABEL);
+		  /* Punt if it has non-label stmts, or isn't local.  */
+		  if (!is_label
+		      || DECL_NONLOCAL (gimple_label_label (stmt)) 
+		      || !gsi_end_p (gsi))
+		    {
+		      gsi_commit_one_edge_insert (e, NULL);
+		      continue;
+		    }
+		}
+	    }
+	  single_edge = e;
+	  count++;
+	}
+    }
+
+  /* If there aren't at least 2 edges, no sharing will happen.  */
+  if (count < 2)
+    {
+      if (single_edge)
+      {
+       /* Add stmts to the edge unless processed specially as a
+          single-block loop latch edge. */
+       if (!process_single_block_loop_latch (single_edge))
+         gsi_commit_one_edge_insert (single_edge, NULL);
+      }
+      return;
+    }
+
+  /* Ensure that we have empty worklists.  */
+#ifdef ENABLE_CHECKING
+  gcc_assert (VEC_length (edge, edge_leader) == 0);
+  gcc_assert (VEC_length (gimple_seq, stmt_list) == 0);
+  gcc_assert (bitmap_empty_p (leader_has_match));
+#endif
+
+  /* Find the "leader" block for each set of unique stmt lists.  Preference is
+     given to FALLTHRU blocks since they would need a GOTO to arrive at another
+     block.  The leader edge destination is the block which all the other edges
+     with the same stmt list will be redirected to.  */
+  have_opportunity = false;
+  FOR_EACH_EDGE (e, ei, bb->preds)
+    {
+      if (PENDING_STMT (e))
+	{
+	  bool found = false;
+
+	  /* Look for the same stmt list in edge leaders list.  */
+	  for (x = 0; VEC_iterate (edge, edge_leader, x, leader); x++)
+	    {
+	      if (identical_stmt_lists_p (leader, e))
+		{
+		  /* Give this edge the same stmt list pointer.  */
+		  PENDING_STMT (e) = NULL;
+		  e->aux = leader;
+		  bitmap_set_bit (leader_has_match, x);
+		  have_opportunity = found = true;
+		  break;
+		}
+	    }
+
+	  /* If no similar stmt list, add this edge to the leader list.  */
+	  if (!found)
+	    {
+	      VEC_safe_push (edge, heap, edge_leader, e);
+	      VEC_safe_push (gimple_seq, heap, stmt_list, PENDING_STMT (e));
+	    }
+	}
+     }
+
+  /* If there are no similar lists, just issue the stmts.  */
+  if (!have_opportunity)
+    {
+      for (x = 0; VEC_iterate (edge, edge_leader, x, leader); x++)
+	gsi_commit_one_edge_insert (leader, NULL);
+      VEC_truncate (edge, edge_leader, 0);
+      VEC_truncate (gimple_seq, stmt_list, 0);
+      bitmap_clear (leader_has_match);
+      return;
+    }
+
+  if (dump_file)
+    fprintf (dump_file, "\nOpportunities in BB %d for stmt/block reduction:\n",
+	     bb->index);
+  
+  /* For each common list, create a forwarding block and issue the stmt's
+     in that block.  */
+  for (x = 0; VEC_iterate (edge, edge_leader, x, leader); x++)
+    if (bitmap_bit_p (leader_has_match, x))
+      {
+	edge new_edge;
+	gimple_stmt_iterator gsi;
+	gimple_seq curr_stmt_list;
+
+	leader_match = leader;
+
+	/* The tree_* cfg manipulation routines use the PENDING_EDGE field
+	   for various PHI manipulations, so it gets cleared when calls are 
+	   made to make_forwarder_block(). So make sure the edge is clear, 
+	   and use the saved stmt list.  */
+	PENDING_STMT (leader) = NULL;
+	leader->aux = leader;
+	curr_stmt_list = VEC_index (gimple_seq, stmt_list, x);
+
+        new_edge = make_forwarder_block (leader->dest, same_stmt_list_p, 
+					 NULL);
+	bb = new_edge->dest;
+	if (dump_file)
+	  {
+	    fprintf (dump_file, "Splitting BB %d for Common stmt list.  ", 
+		     leader->dest->index);
+	    fprintf (dump_file, "Original block is now BB%d.\n", bb->index);
+	    print_gimple_seq (dump_file, curr_stmt_list, 0, TDF_VOPS);
+	  }
+
+	FOR_EACH_EDGE (e, ei, new_edge->src->preds)
+	  {
+	    e->aux = NULL;
+	    if (dump_file)
+	      fprintf (dump_file, "  Edge (%d->%d) lands here.\n", 
+		       e->src->index, e->dest->index);
+	  }
+
+	gsi = gsi_last_bb (leader->dest);
+	gsi_insert_seq_after (&gsi, curr_stmt_list, GSI_NEW_STMT);
+
+	leader_match = NULL;
+	/* We should never get a new block now.  */
+      }
+    else
+      {
+	PENDING_STMT (leader) = VEC_index (gimple_seq, stmt_list, x);
+	gsi_commit_one_edge_insert (leader, NULL);
+      }
+
+   
+  /* Clear the working data structures.  */
+  VEC_truncate (edge, edge_leader, 0);
+  VEC_truncate (gimple_seq, stmt_list, 0);
+  bitmap_clear (leader_has_match);
+}
+
+
+/* This function will analyze the insertions which were performed on edges,
+   and decide whether they should be left on that edge, or whether it is more
+   efficient to emit some subset of them in a single block.  All stmts are
+   inserted somewhere.  */
+
+static void
+perform_edge_inserts (void)
+{
+  basic_block bb;
+
+  if (dump_file)
+    fprintf(dump_file, "Analyzing Edge Insertions.\n");
+
+  /* analyze_edges_for_bb calls make_forwarder_block, which tries to
+     incrementally update the dominator information.  Since we don't
+     need dominator information after this pass, go ahead and free the
+     dominator information.  */
+  free_dominance_info (CDI_DOMINATORS);
+  free_dominance_info (CDI_POST_DOMINATORS);
+
+  /* Allocate data structures used in analyze_edges_for_bb.   */
+  init_analyze_edges_for_bb ();
+
+  FOR_EACH_BB (bb)
+    analyze_edges_for_bb (bb);
+
+  analyze_edges_for_bb (EXIT_BLOCK_PTR);
+
+  /* Free data structures used in analyze_edges_for_bb.   */
+  fini_analyze_edges_for_bb ();
+
+#ifdef ENABLE_CHECKING
+  {
+    edge_iterator ei;
+    edge e;
+    FOR_EACH_BB (bb)
+      {
+	FOR_EACH_EDGE (e, ei, bb->preds)
+	  {
+	    if (PENDING_STMT (e))
+	      error (" Pending stmts not issued on PRED edge (%d, %d)\n", 
+		     e->src->index, e->dest->index);
+	  }
+	FOR_EACH_EDGE (e, ei, bb->succs)
+	  {
+	    if (PENDING_STMT (e))
+	      error (" Pending stmts not issued on SUCC edge (%d, %d)\n", 
+		     e->src->index, e->dest->index);
+	  }
+      }
+    FOR_EACH_EDGE (e, ei, ENTRY_BLOCK_PTR->succs)
+      {
+	if (PENDING_STMT (e))
+	  error (" Pending stmts not issued on ENTRY edge (%d, %d)\n", 
+		 e->src->index, e->dest->index);
+      }
+    FOR_EACH_EDGE (e, ei, EXIT_BLOCK_PTR->preds)
+      {
+	if (PENDING_STMT (e))
+	  error (" Pending stmts not issued on EXIT edge (%d, %d)\n", 
+		 e->src->index, e->dest->index);
+      }
+  }
+#endif
+}
+
+
+/* Remove the ssa-names in the current function and translate them into normal
+   compiler variables.  PERFORM_TER is true if Temporary Expression Replacement
+   should also be used.  */
+
+static void
+remove_ssa_form (bool perform_ter)
+{
+  basic_block bb;
+  gimple *values = NULL;
+  var_map map;
+  gimple_stmt_iterator gsi;
+
+  map = coalesce_ssa_name ();
+
+  /* Return to viewing the variable list as just all reference variables after
+     coalescing has been performed.  */
+  partition_view_normal (map, false);
+
+  if (dump_file && (dump_flags & TDF_DETAILS))
+    {
+      fprintf (dump_file, "After Coalescing:\n");
+      dump_var_map (dump_file, map);
+    }
+
+  if (perform_ter)
+    {
+      values = find_replaceable_exprs (map);
+      if (values && dump_file && (dump_flags & TDF_DETAILS))
+	dump_replaceable_exprs (dump_file, values);
+    }
+
+  /* Assign real variables to the partitions now.  */
+  assign_vars (map);
+
+  if (dump_file && (dump_flags & TDF_DETAILS))
+    {
+      fprintf (dump_file, "After Base variable replacement:\n");
+      dump_var_map (dump_file, map);
+    }
+
+  rewrite_trees (map, values);
+
+  if (values)
+    free (values);
+
+  /* Remove PHI nodes which have been translated back to real variables.  */
+  FOR_EACH_BB (bb)
+    for (gsi = gsi_start_phis (bb); !gsi_end_p (gsi);)
+      remove_phi_node (&gsi, true);
+
+  /* If any copies were inserted on edges, analyze and insert them now.  */
+  perform_edge_inserts ();
+
+  delete_var_map (map);
+}
+
+
+/* Search every PHI node for arguments associated with backedges which
+   we can trivially determine will need a copy (the argument is either
+   not an SSA_NAME or the argument has a different underlying variable
+   than the PHI result).
+
+   Insert a copy from the PHI argument to a new destination at the
+   end of the block with the backedge to the top of the loop.  Update
+   the PHI argument to reference this new destination.  */
+
+static void
+insert_backedge_copies (void)
+{
+  basic_block bb;
+  gimple_stmt_iterator gsi;
+
+  FOR_EACH_BB (bb)
+    {
+      for (gsi = gsi_start_phis (bb); !gsi_end_p (gsi); gsi_next (&gsi))
+	{
+	  gimple phi = gsi_stmt (gsi);
+	  tree result = gimple_phi_result (phi);
+	  tree result_var;
+	  size_t i;
+
+	  if (!is_gimple_reg (result))
+	    continue;
+
+	  result_var = SSA_NAME_VAR (result);
+	  for (i = 0; i < gimple_phi_num_args (phi); i++)
+	    {
+	      tree arg = gimple_phi_arg_def (phi, i);
+	      edge e = gimple_phi_arg_edge (phi, i);
+
+	      /* If the argument is not an SSA_NAME, then we will need a 
+		 constant initialization.  If the argument is an SSA_NAME with
+		 a different underlying variable then a copy statement will be 
+		 needed.  */
+	      if ((e->flags & EDGE_DFS_BACK)
+		  && (TREE_CODE (arg) != SSA_NAME
+		      || SSA_NAME_VAR (arg) != result_var))
+		{
+		  tree name;
+		  gimple stmt, last = NULL;
+		  gimple_stmt_iterator gsi2;
+
+		  gsi2 = gsi_last_bb (gimple_phi_arg_edge (phi, i)->src);
+		  if (!gsi_end_p (gsi2))
+		    last = gsi_stmt (gsi2);
+
+		  /* In theory the only way we ought to get back to the
+		     start of a loop should be with a COND_EXPR or GOTO_EXPR.
+		     However, better safe than sorry. 
+		     If the block ends with a control statement or
+		     something that might throw, then we have to
+		     insert this assignment before the last
+		     statement.  Else insert it after the last statement.  */
+		  if (last && stmt_ends_bb_p (last))
+		    {
+		      /* If the last statement in the block is the definition
+			 site of the PHI argument, then we can't insert
+			 anything after it.  */
+		      if (TREE_CODE (arg) == SSA_NAME
+			  && SSA_NAME_DEF_STMT (arg) == last)
+			continue;
+		    }
+
+		  /* Create a new instance of the underlying variable of the 
+		     PHI result.  */
+		  stmt = gimple_build_assign (result_var,
+					      gimple_phi_arg_def (phi, i));
+		  name = make_ssa_name (result_var, stmt);
+		  gimple_assign_set_lhs (stmt, name);
+
+		  /* Insert the new statement into the block and update
+		     the PHI node.  */
+		  if (last && stmt_ends_bb_p (last))
+		    gsi_insert_before (&gsi2, stmt, GSI_NEW_STMT);
+		  else
+		    gsi_insert_after (&gsi2, stmt, GSI_NEW_STMT);
+		  SET_PHI_ARG_DEF (phi, i, name);
+		}
+	    }
+	}
+    }
+}
+
+/* Take the current function out of SSA form, translating PHIs as described in
+   R. Morgan, ``Building an Optimizing Compiler'',
+   Butterworth-Heinemann, Boston, MA, 1998. pp 176-186.  */
+
+static unsigned int
+rewrite_out_of_ssa (void)
+{
+  /* If elimination of a PHI requires inserting a copy on a backedge,
+     then we will have to split the backedge which has numerous
+     undesirable performance effects.
+
+     A significant number of such cases can be handled here by inserting
+     copies into the loop itself.  */
+  insert_backedge_copies ();
+
+
+  /* Eliminate PHIs which are of no use, such as virtual or dead phis.  */
+  eliminate_useless_phis ();
+
+  if (dump_file && (dump_flags & TDF_DETAILS))
+    gimple_dump_cfg (dump_file, dump_flags & ~TDF_DETAILS);
+
+  remove_ssa_form (flag_tree_ter && !flag_mudflap);
+
+  if (dump_file && (dump_flags & TDF_DETAILS))
+    gimple_dump_cfg (dump_file, dump_flags & ~TDF_DETAILS);
+
+  cfun->gimple_df->in_ssa_p = false;
+  return 0;
+}
+
+
+/* Define the parameters of the out of SSA pass.  */
+
+struct gimple_opt_pass pass_del_ssa = 
+{
+ {
+  GIMPLE_PASS,
+  "optimized",				/* name */
+  NULL,					/* gate */
+  rewrite_out_of_ssa,			/* execute */
+  NULL,					/* sub */
+  NULL,					/* next */
+  0,					/* static_pass_number */
+  TV_TREE_SSA_TO_NORMAL,		/* tv_id */
+  PROP_cfg | PROP_ssa,			/* properties_required */
+  0,					/* properties_provided */
+  /* ??? If TER is enabled, we also kill gimple.  */
+  PROP_ssa,				/* properties_destroyed */
+  TODO_verify_ssa | TODO_verify_flow
+    | TODO_verify_stmts,		/* todo_flags_start */
+  TODO_dump_func
+  | TODO_ggc_collect
+  | TODO_remove_unused_locals		/* todo_flags_finish */
+ }
+};