2010-04-06 Tobias Burnus <burnus@net-b.de>

[pf3gnuchains/gcc-fork.git] / gcc / tree-if-conv.c

diff --git a/gcc/tree-if-conv.c b/gcc/tree-if-conv.c
index d21bb9d..adbdfd8 100644 (file)
--- a/gcc/tree-if-conv.c
+++ b/gcc/tree-if-conv.c
@@ -1,5 +1,6 @@
 /* If-conversion for vectorizer.
 /* If-conversion for vectorizer.

-   Copyright (C) 2004, 2005, 2006, 2007 Free Software Foundation, Inc.
+   Copyright (C) 2004, 2005, 2006, 2007, 2008, 2009, 2010
+   Free Software Foundation, Inc.

    Contributed by Devang Patel <dpatel@apple.com>
 
 This file is part of GCC.
    Contributed by Devang Patel <dpatel@apple.com>
 
 This file is part of GCC.


@@ -18,8 +19,9 @@ 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/>.  */
 
 along with GCC; see the file COPYING3.  If not see
 <http://www.gnu.org/licenses/>.  */
 

-/* This pass implements tree level if-conversion transformation of loops.
-   Initial goal is to help vectorizer vectorize loops with conditions.
+/* This pass implements a tree level if-conversion of loops.  Its
+   initial goal is to help the vectorizer to vectorize loops with
+   conditions.

 
    A short description of if-conversion:
 
 
    A short description of if-conversion:
 


@@ -84,13 +86,12 @@ along with GCC; see the file COPYING3.  If not see
 #include "coretypes.h"
 #include "tm.h"
 #include "tree.h"
 #include "coretypes.h"
 #include "tm.h"
 #include "tree.h"

-#include "c-common.h"

 #include "flags.h"
 #include "timevar.h"
 #include "flags.h"
 #include "timevar.h"

-#include "varray.h"
-#include "rtl.h"

 #include "basic-block.h"
 #include "diagnostic.h"
 #include "basic-block.h"
 #include "diagnostic.h"

+#include "tree-pretty-print.h"
+#include "gimple-pretty-print.h"

 #include "tree-flow.h"
 #include "tree-dump.h"
 #include "cfgloop.h"
 #include "tree-flow.h"
 #include "tree-dump.h"
 #include "cfgloop.h"


@@ -98,132 +99,160 @@ along with GCC; see the file COPYING3.  If not see
 #include "tree-data-ref.h"
 #include "tree-scalar-evolution.h"
 #include "tree-pass.h"
 #include "tree-data-ref.h"
 #include "tree-scalar-evolution.h"
 #include "tree-pass.h"

-#include "target.h"
-
-
-/* local function prototypes */
-static unsigned int main_tree_if_conversion (void);
-static tree tree_if_convert_stmt (struct loop *loop, gimple, tree,
-                                 gimple_stmt_iterator *);
-static void tree_if_convert_cond_stmt (struct loop *, gimple, tree,
-                                      gimple_stmt_iterator *);
-static bool if_convertible_phi_p (struct loop *, basic_block, gimple);
-static bool if_convertible_gimple_assign_stmt_p (struct loop *, basic_block,
-                                                gimple);
-static bool if_convertible_stmt_p (struct loop *, basic_block, gimple);
-static bool if_convertible_bb_p (struct loop *, basic_block, basic_block);
-static bool if_convertible_loop_p (struct loop *, bool);
-static void add_to_predicate_list (basic_block, tree);
-static tree add_to_dst_predicate_list (struct loop * loop, edge,
-                                      tree, tree,
-                                      gimple_stmt_iterator *);
-static void clean_predicate_lists (struct loop *loop);
-static basic_block find_phi_replacement_condition (struct loop *loop,
-                                                  basic_block, tree *,
-                                                  gimple_stmt_iterator *);
-static void replace_phi_with_cond_gimple_assign_stmt (gimple, tree,
-                                                     basic_block,
-                                                     gimple_stmt_iterator *);
-static void process_phi_nodes (struct loop *);
-static void combine_blocks (struct loop *);
-static gimple ifc_temp_var (tree, tree);
-static bool pred_blocks_visited_p (basic_block, bitmap *);
-static basic_block * get_loop_body_in_if_conv_order (const struct loop *loop);
-static bool bb_with_exit_edge_p (struct loop *, basic_block);

 
 /* List of basic blocks in if-conversion-suitable order.  */
 static basic_block *ifc_bbs;
 
 
 /* List of basic blocks in if-conversion-suitable order.  */
 static basic_block *ifc_bbs;
 

-/* Main entry point.
-   Apply if-conversion to the LOOP. Return true if successful otherwise return
-   false. If false is returned then loop remains unchanged.
-   FOR_VECTORIZER is a boolean flag. It indicates whether if-conversion is used
-   for vectorizer or not. If it is used for vectorizer, additional checks are
-   used. (Vectorization checks are not yet implemented).  */
+/* Create a new temp variable of type TYPE.  Add GIMPLE_ASSIGN to assign EXP
+   to the new variable.  */

 
 

-static bool
-tree_if_conversion (struct loop *loop, bool for_vectorizer)
+static gimple
+ifc_temp_var (tree type, tree exp)

 {
 {

-  basic_block bb;
-  gimple_stmt_iterator itr;
-  unsigned int i;
+  const char *name = "_ifc_";
+  tree var, new_name;
+  gimple stmt;

 
 

-  ifc_bbs = NULL;
+  /* Create new temporary variable.  */
+  var = create_tmp_var (type, name);
+  add_referenced_var (var);
+
+  /* Build new statement to assign EXP to new variable.  */
+  stmt = gimple_build_assign (var, exp);
+
+  /* Get SSA name for the new variable and set make new statement
+     its definition statement.  */
+  new_name = make_ssa_name (var, stmt);
+  gimple_assign_set_lhs (stmt, new_name);
+  SSA_NAME_DEF_STMT (new_name) = stmt;
+  update_stmt (stmt);
+
+  return stmt;
+}

 
 

-  /* if-conversion is not appropriate for all loops. First, check if loop  is
-     if-convertible or not.  */
-  if (!if_convertible_loop_p (loop, for_vectorizer))
+/* Add condition NEW_COND to the predicate list of basic block BB.  */
+
+static void
+add_to_predicate_list (basic_block bb, tree new_cond)
+{
+  tree cond = (tree) bb->aux;
+
+  if (cond)
+    cond = fold_build2_loc (EXPR_LOCATION (cond),
+                           TRUTH_OR_EXPR, boolean_type_node,
+                           unshare_expr (cond), new_cond);
+  else
+    cond = new_cond;
+
+  bb->aux = cond;
+}
+
+/* Add the condition COND to the previous condition PREV_COND, and add this
+   to the predicate list of the destination of edge E.  GSI is the
+   place where the gimplification of the resulting condition should
+   output code.  LOOP is the loop to be if-converted.  */
+
+static tree
+add_to_dst_predicate_list (struct loop *loop, edge e,
+                          tree prev_cond, tree cond,
+                          gimple_stmt_iterator *gsi)
+{
+  tree new_cond = NULL_TREE;
+
+  if (!flow_bb_inside_loop_p (loop, e->dest))
+    return NULL_TREE;
+
+  if (prev_cond == boolean_true_node || !prev_cond)
+    new_cond = unshare_expr (cond);
+  else

     {
     {

-      if (dump_file && (dump_flags & TDF_DETAILS))
-       fprintf (dump_file,"-------------------------\n");
-      if (ifc_bbs)
-       {
-         free (ifc_bbs);
-         ifc_bbs = NULL;
-       }
-      free_dominance_info (CDI_POST_DOMINATORS);
-      return false;
+      tree tmp;
+      gimple tmp_stmt = NULL;
+
+      prev_cond = force_gimple_operand_gsi (gsi, unshare_expr (prev_cond),
+                                           true, NULL, true, GSI_SAME_STMT);
+
+      cond = force_gimple_operand_gsi (gsi, unshare_expr (cond),
+                                      true, NULL, true, GSI_SAME_STMT);
+
+      /* Add the condition COND to the e->aux field.  In case the edge
+        destination is a PHI node, this condition will be added to
+        the block predicate to construct a complete condition.  */
+      e->aux = cond;
+
+      tmp = build2 (TRUTH_AND_EXPR, boolean_type_node,
+                   unshare_expr (prev_cond), cond);
+      tmp_stmt = ifc_temp_var (boolean_type_node, tmp);
+      gsi_insert_before (gsi, tmp_stmt, GSI_SAME_STMT);
+      new_cond = gimple_assign_lhs (tmp_stmt);

     }
 
     }
 

-  /* Do actual work now.  */
-  for (i = 0; i < loop->num_nodes; i++)
-    {
-      tree cond;
+  add_to_predicate_list (e->dest, new_cond);
+  return new_cond;
+}

 
 

-      bb = ifc_bbs [i];
+/* Return true if one of the successor edges of BB exits LOOP.  */

 
 

-      /* Update condition using predicate list.  */
-      cond = (tree) bb->aux;
+static bool
+bb_with_exit_edge_p (struct loop *loop, basic_block bb)
+{
+  edge e;
+  edge_iterator ei;

 
 

-      /* Process all statements in this basic block.
-        Remove conditional expression, if any, and annotate
-        destination basic block(s) appropriately.  */
-      for (itr = gsi_start_bb (bb); !gsi_end_p (itr); /* empty */)
-       {
-         gimple t = gsi_stmt (itr);
-         cond = tree_if_convert_stmt (loop, t, cond, &itr);
-         if (!gsi_end_p (itr))
-           gsi_next (&itr);
-       }
+  FOR_EACH_EDGE (e, ei, bb->succs)
+    if (loop_exit_edge_p (loop, e))
+      return true;

 
 

-      /* If current bb has only one successor, then consider it as an
-        unconditional goto.  */
-      if (single_succ_p (bb))
-       {
-         basic_block bb_n = single_succ (bb);
+  return false;
+}

 
 

-         /* Successor bb inherits predicate of its predecessor. If there
-            is no predicate in predecessor bb, then consider successor bb
-            as always executed.  */
-         if (cond == NULL_TREE)
-           cond = boolean_true_node;
+/* STMT is a GIMPLE_COND.  Update two destination's predicate list.
+   Remove COND_EXPR, if it is not the exit condition of LOOP.
+   Otherwise update the exit condition of LOOP appropriately.  GSI
+   points to the statement STMT.  */

 
 

-         add_to_predicate_list (bb_n, cond);
-       }
-    }
+static void
+tree_if_convert_cond_stmt (struct loop *loop, gimple stmt, tree cond,
+                          gimple_stmt_iterator *gsi)
+{
+  tree c2;
+  edge true_edge, false_edge;
+  location_t loc = gimple_location (stmt);
+  tree c = fold_build2_loc (loc, gimple_cond_code (stmt), boolean_type_node,
+                           gimple_cond_lhs (stmt), gimple_cond_rhs (stmt));

 
 

-  /* Now, all statements are if-converted and basic blocks are
-     annotated appropriately. Combine all basic block into one huge
-     basic block.  */
-  combine_blocks (loop);
+  extract_true_false_edges_from_block (gimple_bb (stmt),
+                                      &true_edge, &false_edge);

 
 

-  /* clean up */
-  clean_predicate_lists (loop);
-  free (ifc_bbs);
-  ifc_bbs = NULL;
+  /* Add new condition into destination's predicate list.  */

 
 

-  return true;
+  /* If C is true, then TRUE_EDGE is taken.  */
+  add_to_dst_predicate_list (loop, true_edge, cond, c, gsi);
+
+  /* If C is false, then FALSE_EDGE is taken.  */
+  c2 = invert_truthvalue_loc (loc, unshare_expr (c));
+  add_to_dst_predicate_list (loop, false_edge, cond, c2, gsi);
+
+  /* Now this conditional statement is redundant.  Remove it.  But, do
+     not remove the exit condition!  Update the exit condition using
+     the new condition.  */
+  if (!bb_with_exit_edge_p (loop, gimple_bb (stmt)))
+    {
+      gsi_remove (gsi, true);
+      cond = NULL_TREE;
+    }

 }
 
 }
 

-/* if-convert stmt T which is part of LOOP.
-   If T is a GIMPLE_ASSIGN then it is converted into conditional modify
-   expression using COND.  For conditional expressions, add condition in the
-   destination basic block's predicate list and remove conditional
-   expression itself. BSI is the iterator used to traverse statements of
-   loop. It is used here when it is required to delete current statement.  */
+/* If-convert stmt T which is part of LOOP.
+
+   If T is a GIMPLE_ASSIGN then it is converted into a conditional
+   modify expression using COND.  For conditional expressions, add
+   a condition in the destination basic block's predicate list and
+   remove the conditional expression itself.  GSI points to the
+   statement T.  */

 
 static tree
 
 static tree

-tree_if_convert_stmt (struct loop *  loop, gimple t, tree cond,
+tree_if_convert_stmt (struct loop *loop, gimple t, tree cond,

                      gimple_stmt_iterator *gsi)
 {
   if (dump_file && (dump_flags & TDF_DETAILS))
                      gimple_stmt_iterator *gsi)
 {
   if (dump_file && (dump_flags & TDF_DETAILS))


@@ -239,12 +268,21 @@ tree_if_convert_stmt (struct loop *  loop, gimple t, tree cond,
     case GIMPLE_LABEL:
       break;
 
     case GIMPLE_LABEL:
       break;
 

+    case GIMPLE_DEBUG:
+      /* ??? Should there be conditional GIMPLE_DEBUG_BINDs?  */
+      if (gimple_debug_bind_p (gsi_stmt (*gsi)))
+       {
+         gimple_debug_bind_reset_value (gsi_stmt (*gsi));
+         update_stmt (gsi_stmt (*gsi));
+       }
+      break;
+

     case GIMPLE_ASSIGN:
     case GIMPLE_ASSIGN:

-      /* This GIMPLE_ASSIGN is killing previous value of LHS. Appropriate
-        value will be selected by PHI node based on condition. It is possible
+      /* This GIMPLE_ASSIGN is killing previous value of LHS.  Appropriate
+        value will be selected by PHI node based on condition.  It is possible

         that before this transformation, PHI nodes was selecting default
         that before this transformation, PHI nodes was selecting default

-        value and now it will use this new value. This is OK because it does 
-        not change validity the program.  */
+        value and now it will use this new value.  This is OK because it does
+        not change the validity of the program.  */

       break;
 
     case GIMPLE_COND:
       break;
 
     case GIMPLE_COND:


@@ -257,55 +295,17 @@ tree_if_convert_stmt (struct loop *  loop, gimple t, tree cond,
     default:
       gcc_unreachable ();
     }
     default:
       gcc_unreachable ();
     }

-  return cond;
-}
-
-/* STMT is a GIMPLE_COND. Update two destination's predicate list.
-   Remove COND_EXPR, if it is not the loop exit condition. Otherwise
-   update loop exit condition appropriately.  GSI is the iterator
-   used to traverse statement list. STMT is part of loop LOOP.  */
-
-static void
-tree_if_convert_cond_stmt (struct loop *loop, gimple stmt, tree cond,
-                          gimple_stmt_iterator *gsi)
-{
-  tree c, c2;
-  edge true_edge, false_edge;
-
-  gcc_assert (gimple_code (stmt) == GIMPLE_COND);

 
 

-  c = fold_build2 (gimple_cond_code (stmt), boolean_type_node,
-                  gimple_cond_lhs (stmt), gimple_cond_rhs (stmt));
-
-  extract_true_false_edges_from_block (gimple_bb (stmt),
-                                      &true_edge, &false_edge);
-
-  /* Add new condition into destination's predicate list.  */
-
-  /* If C is true then TRUE_EDGE is taken.  */
-  add_to_dst_predicate_list (loop, true_edge, cond, c, gsi);
-
-  /* If 'c' is false then FALSE_EDGE is taken.  */
-  c2 = invert_truthvalue (unshare_expr (c));
-  add_to_dst_predicate_list (loop, false_edge, cond, c2, gsi);
-
-  /* Now this conditional statement is redundant. Remove it.
-     But, do not remove exit condition! Update exit condition
-     using new condition.  */
-  if (!bb_with_exit_edge_p (loop, gimple_bb (stmt)))
-    {
-      gsi_remove (gsi, true);
-      cond = NULL_TREE;
-    }
-  return;
+  return cond;

 }
 
 }
 

-/* Return true, iff PHI is if-convertible. PHI is part of loop LOOP
+/* Return true when PHI is if-convertible.  PHI is part of loop LOOP

    and it belongs to basic block BB.
    and it belongs to basic block BB.

-   PHI is not if-convertible
-   - if it has more than 2 arguments.
-   - Virtual PHI is immediately used in another PHI node.
-   - Virtual PHI on BB other than header.  */
+
+   PHI is not if-convertible if:
+   - it has more than 2 arguments,
+   - virtual PHI is immediately used in another PHI node,
+   - virtual PHI on BB other than header.  */

 
 static bool
 if_convertible_phi_p (struct loop *loop, basic_block bb, gimple phi)
 
 static bool
 if_convertible_phi_p (struct loop *loop, basic_block bb, gimple phi)


@@ -348,21 +348,20 @@ if_convertible_phi_p (struct loop *loop, basic_block bb, gimple phi)
   return true;
 }
 
   return true;
 }
 

-/* Return true, if STMT is if-convertible.
+/* Return true when STMT is if-convertible.
+

    GIMPLE_ASSIGN statement is not if-convertible if,
    GIMPLE_ASSIGN statement is not if-convertible if,

-   - It is not movable.
-   - It could trap.
+   - it is not movable,
+   - it could trap,

    - LHS is not var decl.
    - LHS is not var decl.

-  GIMPLE_ASSIGN is part of block BB, which is inside loop LOOP.  */
+
+   GIMPLE_ASSIGN is part of block BB, which is inside loop LOOP.  */

 
 static bool
 if_convertible_gimple_assign_stmt_p (struct loop *loop, basic_block bb,
                                     gimple stmt)
 {
 
 static bool
 if_convertible_gimple_assign_stmt_p (struct loop *loop, basic_block bb,
                                     gimple stmt)
 {

-  tree lhs;
-
-  if (!is_gimple_assign (stmt))
-    return false;
+  tree lhs = gimple_assign_lhs (stmt);

 
   if (dump_file && (dump_flags & TDF_DETAILS))
     {
 
   if (dump_file && (dump_flags & TDF_DETAILS))
     {


@@ -370,8 +369,6 @@ if_convertible_gimple_assign_stmt_p (struct loop *loop, basic_block bb,
       print_gimple_stmt (dump_file, stmt, 0, TDF_SLIM);
     }
 
       print_gimple_stmt (dump_file, stmt, 0, TDF_SLIM);
     }
 

-  lhs = gimple_assign_lhs (stmt);
-

   /* Some of these constrains might be too conservative.  */
   if (stmt_ends_bb_p (stmt)
       || gimple_has_volatile_ops (stmt)
   /* Some of these constrains might be too conservative.  */
   if (stmt_ends_bb_p (stmt)
       || gimple_has_volatile_ops (stmt)


@@ -408,11 +405,13 @@ if_convertible_gimple_assign_stmt_p (struct loop *loop, basic_block bb,
   return true;
 }
 
   return true;
 }
 

-/* Return true, iff STMT is if-convertible.
-   Statement is if-convertible if,
-   - It is if-convertible GIMPLE_ASSGIN
-   - It is GIMPLE_LABEL or GIMPLE_COND.
-   STMT is inside block BB, which is inside loop LOOP.  */
+/* Return true when STMT is if-convertible.
+
+   A statement is if-convertible if:
+   - it is an if-convertible GIMPLE_ASSGIN,
+   - it is a GIMPLE_LABEL or a GIMPLE_COND.
+
+   STMT is inside BB, which is inside loop LOOP.  */

 
 static bool
 if_convertible_stmt_p (struct loop *loop, basic_block bb, gimple stmt)
 
 static bool
 if_convertible_stmt_p (struct loop *loop, basic_block bb, gimple stmt)


@@ -420,16 +419,12 @@ if_convertible_stmt_p (struct loop *loop, basic_block bb, gimple stmt)
   switch (gimple_code (stmt))
     {
     case GIMPLE_LABEL:
   switch (gimple_code (stmt))
     {
     case GIMPLE_LABEL:

-      break;
+    case GIMPLE_DEBUG:
+    case GIMPLE_COND:
+      return true;

 
     case GIMPLE_ASSIGN:
 
     case GIMPLE_ASSIGN:

-
-      if (!if_convertible_gimple_assign_stmt_p (loop, bb, stmt))
-       return false;
-      break;
-
-    case GIMPLE_COND:
-      break;
+      return if_convertible_gimple_assign_stmt_p (loop, bb, stmt);

 
     default:
       /* Don't know what to do with 'em so don't do anything.  */
 
     default:
       /* Don't know what to do with 'em so don't do anything.  */


@@ -445,14 +440,16 @@ if_convertible_stmt_p (struct loop *loop, basic_block bb, gimple stmt)
   return true;
 }
 
   return true;
 }
 

-/* Return true, iff BB is if-convertible.
-   Note: This routine does _not_ check basic block statements and phis.
-   Basic block is not if-convertible if,
-   - Basic block is non-empty and it is after exit block (in BFS order).
-   - Basic block is after exit block but before latch.
-   - Basic block edge(s) is not normal.
-   EXIT_BB_SEEN is true if basic block with exit edge is already seen.
-   BB is inside loop LOOP.  */
+/* Return true when BB is if-convertible.  This routine does not check
+   basic block's statements and phis.
+
+   A basic block is not if-convertible if:
+   - it is non-empty and it is after the exit block (in BFS order),
+   - it is after the exit block but before the latch,
+   - its edges are not normal.
+
+   EXIT_BB is the basic block containing the exit of the LOOP.  BB is
+   inside LOOP.  */

 
 static bool
 if_convertible_bb_p (struct loop *loop, basic_block bb, basic_block exit_bb)
 
 static bool
 if_convertible_bb_p (struct loop *loop, basic_block bb, basic_block exit_bb)


@@ -477,7 +474,7 @@ if_convertible_bb_p (struct loop *loop, basic_block bb, basic_block exit_bb)
            fprintf (dump_file, "non empty basic block after exit bb\n");
          return false;
        }
            fprintf (dump_file, "non empty basic block after exit bb\n");
          return false;
        }

-      else if (bb == loop->latch 
+      else if (bb == loop->latch

               && bb != exit_bb
               && !dominated_by_p (CDI_DOMINATORS, bb, exit_bb))
          {
               && bb != exit_bb
               && !dominated_by_p (CDI_DOMINATORS, bb, exit_bb))
          {


@@ -493,26 +490,97 @@ if_convertible_bb_p (struct loop *loop, basic_block bb, basic_block exit_bb)
        (EDGE_ABNORMAL_CALL | EDGE_EH | EDGE_ABNORMAL | EDGE_IRREDUCIBLE_LOOP))
       {
        if (dump_file && (dump_flags & TDF_DETAILS))
        (EDGE_ABNORMAL_CALL | EDGE_EH | EDGE_ABNORMAL | EDGE_IRREDUCIBLE_LOOP))
       {
        if (dump_file && (dump_flags & TDF_DETAILS))

-         fprintf (dump_file,"Difficult to handle edges\n");
+         fprintf (dump_file, "Difficult to handle edges\n");

        return false;
       }
 
   return true;
 }
 
        return false;
       }
 
   return true;
 }
 

-/* Return true, iff LOOP is if-convertible.
-   LOOP is if-convertible if,
-   - It is innermost.
-   - It has two or more basic blocks.
-   - It has only one exit.
-   - Loop header is not the exit edge.
-   - If its basic blocks and phi nodes are if convertible. See above for
-     more info.
-   FOR_VECTORIZER enables vectorizer specific checks. For example, support
-   for vector conditions, data dependency checks etc.. (Not implemented yet).  */
+/* Return true when all predecessor blocks of BB are visited.  The
+   VISITED bitmap keeps track of the visited blocks.  */
+
+static bool
+pred_blocks_visited_p (basic_block bb, bitmap *visited)
+{
+  edge e;
+  edge_iterator ei;
+  FOR_EACH_EDGE (e, ei, bb->preds)
+    if (!bitmap_bit_p (*visited, e->src->index))
+      return false;
+
+  return true;
+}
+
+/* Get body of a LOOP in suitable order for if-conversion.  It is
+   caller's responsibility to deallocate basic block list.
+   If-conversion suitable order is, breadth first sort (BFS) order
+   with an additional constraint: select a block only if all its
+   predecessors are already selected.  */
+
+static basic_block *
+get_loop_body_in_if_conv_order (const struct loop *loop)
+{
+  basic_block *blocks, *blocks_in_bfs_order;
+  basic_block bb;
+  bitmap visited;
+  unsigned int index = 0;
+  unsigned int visited_count = 0;
+
+  gcc_assert (loop->num_nodes);
+  gcc_assert (loop->latch != EXIT_BLOCK_PTR);
+
+  blocks = XCNEWVEC (basic_block, loop->num_nodes);
+  visited = BITMAP_ALLOC (NULL);
+
+  blocks_in_bfs_order = get_loop_body_in_bfs_order (loop);
+
+  index = 0;
+  while (index < loop->num_nodes)
+    {
+      bb = blocks_in_bfs_order [index];
+
+      if (bb->flags & BB_IRREDUCIBLE_LOOP)
+       {
+         free (blocks_in_bfs_order);
+         BITMAP_FREE (visited);
+         free (blocks);
+         return NULL;
+       }
+
+      if (!bitmap_bit_p (visited, bb->index))
+       {
+         if (pred_blocks_visited_p (bb, &visited)
+             || bb == loop->header)
+           {
+             /* This block is now visited.  */
+             bitmap_set_bit (visited, bb->index);
+             blocks[visited_count++] = bb;
+           }
+       }
+
+      index++;
+
+      if (index == loop->num_nodes
+         && visited_count != loop->num_nodes)
+       /* Not done yet.  */
+       index = 0;
+    }
+  free (blocks_in_bfs_order);
+  BITMAP_FREE (visited);
+  return blocks;
+}
+
+/* Return true when LOOP is if-convertible.
+   LOOP is if-convertible if:
+   - it is innermost,
+   - it has two or more basic blocks,
+   - it has only one exit,
+   - loop header is not the exit edge,
+   - if its basic blocks and phi nodes are if convertible.  */

 
 static bool
 
 static bool

-if_convertible_loop_p (struct loop *loop, bool for_vectorizer ATTRIBUTE_UNUSED)
+if_convertible_loop_p (struct loop *loop)

 {
   basic_block bb;
   gimple_stmt_iterator itr;
 {
   basic_block bb;
   gimple_stmt_iterator itr;


@@ -575,21 +643,16 @@ if_convertible_loop_p (struct loop *loop, bool for_vectorizer ATTRIBUTE_UNUSED)
       if (!if_convertible_bb_p (loop, bb, exit_bb))
        return false;
 
       if (!if_convertible_bb_p (loop, bb, exit_bb))
        return false;
 

-      /* Check statements.  */

       for (itr = gsi_start_bb (bb); !gsi_end_p (itr); gsi_next (&itr))
        if (!if_convertible_stmt_p (loop, bb, gsi_stmt (itr)))
          return false;
       for (itr = gsi_start_bb (bb); !gsi_end_p (itr); gsi_next (&itr))
        if (!if_convertible_stmt_p (loop, bb, gsi_stmt (itr)))
          return false;

-      /* ??? Check data dependency for vectorizer.  */

 
 

-      /* What about phi nodes ? */

       itr = gsi_start_phis (bb);
 
       itr = gsi_start_phis (bb);
 

-      /* Clear aux field of incoming edges to a bb with a phi node.  */

       if (!gsi_end_p (itr))
        FOR_EACH_EDGE (e, ei, bb->preds)
          e->aux = NULL;
 
       if (!gsi_end_p (itr))
        FOR_EACH_EDGE (e, ei, bb->preds)
          e->aux = NULL;
 

-      /* Check statements.  */

       for (; !gsi_end_p (itr); gsi_next (&itr))
        if (!if_convertible_phi_p (loop, bb, gsi_stmt (itr)))
          return false;
       for (; !gsi_end_p (itr); gsi_next (&itr))
        if (!if_convertible_phi_p (loop, bb, gsi_stmt (itr)))
          return false;


@@ -598,8 +661,6 @@ if_convertible_loop_p (struct loop *loop, bool for_vectorizer ATTRIBUTE_UNUSED)
        exit_bb = bb;
     }
 
        exit_bb = bb;
     }
 

-  /* OK. Did not find any potential issues so go ahead in if-convert
-     this loop. Now there is no looking back.  */

   if (dump_file)
     fprintf (dump_file,"Applying if-conversion\n");
 
   if (dump_file)
     fprintf (dump_file,"Applying if-conversion\n");
 


@@ -607,68 +668,11 @@ if_convertible_loop_p (struct loop *loop, bool for_vectorizer ATTRIBUTE_UNUSED)
   return true;
 }
 
   return true;
 }
 

-/* Add condition COND into predicate list of basic block BB.  */
-
-static void
-add_to_predicate_list (basic_block bb, tree new_cond)
-{
-  tree cond = (tree) bb->aux;
-
-  if (cond)
-    cond = fold_build2 (TRUTH_OR_EXPR, boolean_type_node,
-                       unshare_expr (cond), new_cond);
-  else
-    cond = new_cond;
-
-  bb->aux = cond;
-}
-
-/* Add condition COND into BB's predicate list.  PREV_COND is
-   existing condition.  */
-
-static tree
-add_to_dst_predicate_list (struct loop * loop, edge e,
-                          tree prev_cond, tree cond,
-                          gimple_stmt_iterator *gsi)
-{
-  tree new_cond = NULL_TREE;
-
-  if (!flow_bb_inside_loop_p (loop, e->dest))
-    return NULL_TREE;
-
-  if (prev_cond == boolean_true_node || !prev_cond)
-    new_cond = unshare_expr (cond);
-  else
-    {
-      tree tmp;
-      gimple tmp_stmt = NULL;
-
-      prev_cond = force_gimple_operand_gsi (gsi, unshare_expr (prev_cond),
-                                           true, NULL, true, GSI_SAME_STMT);
-
-      cond = force_gimple_operand_gsi (gsi, unshare_expr (cond),
-                                      true, NULL, true, GSI_SAME_STMT);
-
-      /* Add the condition to aux field of the edge.  In case edge
-        destination is a PHI node, this condition will be ANDed with
-        block predicate to construct complete condition.  */
-      e->aux = cond;
-
-      /* new_cond == prev_cond AND cond */
-      tmp = build2 (TRUTH_AND_EXPR, boolean_type_node,
-                   unshare_expr (prev_cond), cond);
-      tmp_stmt = ifc_temp_var (boolean_type_node, tmp);
-      gsi_insert_before (gsi, tmp_stmt, GSI_SAME_STMT);
-      new_cond = gimple_assign_lhs (tmp_stmt);
-    }
-  add_to_predicate_list (e->dest, new_cond);
-  return new_cond;
-}
-
-/* During if-conversion aux field from basic block structure is used to hold
-   predicate list. Clean each basic block's predicate list for the given LOOP.
-   Also clean aux field of successor edges, used to hold true and false
-   condition from conditional expression.  */
+/* During if-conversion, the bb->aux field is used to hold a predicate
+   list.  This function cleans for all the basic blocks in the given
+   LOOP their predicate list.  It also cleans up the e->aux field of
+   all the successor edges: e->aux is used to hold the true and false
+   conditions for conditional expressions.  */

 
 static void
 clean_predicate_lists (struct loop *loop)
 
 static void
 clean_predicate_lists (struct loop *loop)


@@ -688,12 +692,14 @@ clean_predicate_lists (struct loop *loop)
   free (bb);
 }
 
   free (bb);
 }
 

-/* Basic block BB has two predecessors. Using predecessor's aux field, set
-   appropriate condition COND for the PHI node replacement. Return true block
-   whose phi arguments are selected when cond is true.  */
+/* Basic block BB has two predecessors.  Using predecessor's bb->aux
+   field, set appropriate condition COND for the PHI node replacement.
+   Return true block whose phi arguments are selected when cond is
+   true.  LOOP is the loop containing the if-converted region, GSI is
+   the place to insert the code for the if-conversion.  */

 
 static basic_block
 
 static basic_block

-find_phi_replacement_condition (struct loop *loop, 
+find_phi_replacement_condition (struct loop *loop,

                                basic_block bb, tree *cond,
                                 gimple_stmt_iterator *gsi)
 {
                                basic_block bb, tree *cond,
                                 gimple_stmt_iterator *gsi)
 {


@@ -711,7 +717,7 @@ find_phi_replacement_condition (struct loop *loop,
        S2: x = c ? b : a;
 
        S2 is preferred over S1. Make 'b' first_bb and use its condition.
        S2: x = c ? b : a;
 
        S2 is preferred over S1. Make 'b' first_bb and use its condition.

-       
+

      2) Do not make loop header first_bb.
 
      3)
      2) Do not make loop header first_bb.
 
      3)


@@ -722,7 +728,7 @@ find_phi_replacement_condition (struct loop *loop,
 
        S3: x = (c == d) ? b : a;
 
 
        S3: x = (c == d) ? b : a;
 

-       S3 is preferred over S1 and S2*, Make 'b' first_bb and use 
+       S3 is preferred over S1 and S2*, Make 'b' first_bb and use

        its condition.
 
      4) If  pred B is dominated by pred A then use pred B's condition.
        its condition.
 
      4) If  pred B is dominated by pred A then use pred B's condition.


@@ -749,15 +755,13 @@ find_phi_replacement_condition (struct loop *loop,
     {
       *cond = (tree) (second_edge->src)->aux;
 
     {
       *cond = (tree) (second_edge->src)->aux;
 

-      /* If there is a condition on an incoming edge,
-        AND it with the incoming bb predicate.  */
+      /* If there is a condition on an incoming edge, add it to the
+        incoming bb predicate.  */

       if (second_edge->aux)
        *cond = build2 (TRUTH_AND_EXPR, boolean_type_node,
                        *cond, (tree) second_edge->aux);
 
       if (TREE_CODE (*cond) == TRUTH_NOT_EXPR)
       if (second_edge->aux)
        *cond = build2 (TRUTH_AND_EXPR, boolean_type_node,
                        *cond, (tree) second_edge->aux);
 
       if (TREE_CODE (*cond) == TRUTH_NOT_EXPR)

-       /* We can be smart here and choose inverted
-          condition without switching bbs.  */

        *cond = invert_truthvalue (*cond);
       else
        /* Select non loop header bb.  */
        *cond = invert_truthvalue (*cond);
       else
        /* Select non loop header bb.  */


@@ -765,21 +769,20 @@ find_phi_replacement_condition (struct loop *loop,
     }
   else
     {
     }
   else
     {

-      /* FIRST_BB is not loop header */

       *cond = (tree) (first_edge->src)->aux;
 
       *cond = (tree) (first_edge->src)->aux;
 

-      /* If there is a condition on an incoming edge,
-        AND it with the incoming bb predicate.  */
+      /* If there is a condition on an incoming edge, add it to the
+        incoming bb predicate.  */

       if (first_edge->aux)
        *cond = build2 (TRUTH_AND_EXPR, boolean_type_node,
                        *cond, (tree) first_edge->aux);
     }
 
       if (first_edge->aux)
        *cond = build2 (TRUTH_AND_EXPR, boolean_type_node,
                        *cond, (tree) first_edge->aux);
     }
 

-  /* Create temp. for the condition. Vectorizer prefers to have gimple
-     value as condition. Various targets use different means to communicate
-     condition in vector compare operation. Using gimple value allows
-     compiler to emit vector compare and select RTL without exposing
-     compare's result.  */
+  /* Gimplify the condition: the vectorizer prefers to have gimple
+     values as conditions.  Various targets use different means to
+     communicate conditions in vector compare operations.  Using a
+     gimple value allows the compiler to emit vector compare and
+     select RTL without exposing compare's result.  */

   *cond = force_gimple_operand_gsi (gsi, unshare_expr (*cond),
                                    false, NULL_TREE,
                                    true, GSI_SAME_STMT);
   *cond = force_gimple_operand_gsi (gsi, unshare_expr (*cond),
                                    false, NULL_TREE,
                                    true, GSI_SAME_STMT);


@@ -797,16 +800,17 @@ find_phi_replacement_condition (struct loop *loop,
   return first_edge->src;
 }
 
   return first_edge->src;
 }
 

+/* Replace PHI node with conditional modify expr using COND.  This
+   routine does not handle PHI nodes with more than two arguments.

 
 

-/* Replace PHI node with conditional modify expr using COND.
-   This routine does not handle PHI nodes with more than two arguments.

    For example,
      S1: A = PHI <x1(1), x2(5)
    is converted into,
      S2: A = cond ? x1 : x2;
    For example,
      S1: A = PHI <x1(1), x2(5)
    is converted into,
      S2: A = cond ? x1 : x2;

-   S2 is inserted at the top of basic block's statement list.
-   When COND is true, phi arg from TRUE_BB is selected.
-*/
+
+   The generated code is inserted at GSI that points to the top of
+   basic block's statement list.  When COND is true, phi arg from
+   TRUE_BB is selected.  */

 
 static void
 replace_phi_with_cond_gimple_assign_stmt (gimple phi, tree cond,
 
 static void
 replace_phi_with_cond_gimple_assign_stmt (gimple phi, tree cond,


@@ -818,12 +822,9 @@ replace_phi_with_cond_gimple_assign_stmt (gimple phi, tree cond,
   tree rhs;
   tree arg_0, arg_1;
 
   tree rhs;
   tree arg_0, arg_1;
 

-  gcc_assert (gimple_code (phi) == GIMPLE_PHI);
-  
-  /* If this is not filtered earlier, then now it is too late.  */
-  gcc_assert (gimple_phi_num_args (phi) == 2);
+  gcc_assert (gimple_code (phi) == GIMPLE_PHI
+             && gimple_phi_num_args (phi) == 2);

 
 

-  /* Find basic block and initialize iterator.  */

   bb = gimple_bb (phi);
 
   /* Use condition that is not TRUTH_NOT_EXPR in conditional modify expr.  */
   bb = gimple_bb (phi);
 
   /* Use condition that is not TRUTH_NOT_EXPR in conditional modify expr.  */


@@ -843,13 +844,8 @@ replace_phi_with_cond_gimple_assign_stmt (gimple phi, tree cond,
                unshare_expr (cond), unshare_expr (arg_0),
                unshare_expr (arg_1));
 
                unshare_expr (cond), unshare_expr (arg_0),
                unshare_expr (arg_1));
 

-  /* Create new GIMPLE_ASSIGN statement using RHS.  */

   new_stmt = gimple_build_assign (unshare_expr (PHI_RESULT (phi)), rhs);
   new_stmt = gimple_build_assign (unshare_expr (PHI_RESULT (phi)), rhs);

-
-  /* Make new statement definition of the original phi result.  */

   SSA_NAME_DEF_STMT (gimple_phi_result (phi)) = new_stmt;
   SSA_NAME_DEF_STMT (gimple_phi_result (phi)) = new_stmt;

-
-  /* Insert using iterator.  */

   gsi_insert_before (gsi, new_stmt, GSI_SAME_STMT);
   update_stmt (new_stmt);
 
   gsi_insert_before (gsi, new_stmt, GSI_SAME_STMT);
   update_stmt (new_stmt);
 


@@ -860,8 +856,8 @@ replace_phi_with_cond_gimple_assign_stmt (gimple phi, tree cond,
     }
 }
 
     }
 }
 

-/* Process phi nodes for the given  LOOP.  Replace phi nodes with cond
-   modify expr.  */
+/* Process phi nodes for the given LOOP.  Replace phi nodes with
+   conditional modify expressions.  */

 
 static void
 process_phi_nodes (struct loop *loop)
 
 static void
 process_phi_nodes (struct loop *loop)


@@ -870,7 +866,6 @@ process_phi_nodes (struct loop *loop)
   unsigned int orig_loop_num_nodes = loop->num_nodes;
   unsigned int i;
 
   unsigned int orig_loop_num_nodes = loop->num_nodes;
   unsigned int i;
 

-  /* Replace phi nodes with cond. modify expr.  */

   for (i = 1; i < orig_loop_num_nodes; i++)
     {
       gimple phi;
   for (i = 1; i < orig_loop_num_nodes; i++)
     {
       gimple phi;


@@ -885,7 +880,7 @@ process_phi_nodes (struct loop *loop)
       phi_gsi = gsi_start_phis (bb);
       gsi = gsi_after_labels (bb);
 
       phi_gsi = gsi_start_phis (bb);
       gsi = gsi_after_labels (bb);
 

-      /* BB has two predecessors. Using predecessor's aux field, set
+      /* BB has two predecessors.  Using predecessor's aux field, set

         appropriate condition for the PHI node replacement.  */
       if (!gsi_end_p (phi_gsi))
        true_bb = find_phi_replacement_condition (loop, bb, &cond, &gsi);
         appropriate condition for the PHI node replacement.  */
       if (!gsi_end_p (phi_gsi))
        true_bb = find_phi_replacement_condition (loop, bb, &cond, &gsi);


@@ -899,11 +894,10 @@ process_phi_nodes (struct loop *loop)
        }
       set_phi_nodes (bb, NULL);
     }
        }
       set_phi_nodes (bb, NULL);
     }

-  return;

 }
 
 }
 

-/* Combine all basic block from the given LOOP into one or two super
-   basic block.  Replace PHI nodes with conditional modify expression.  */
+/* Combine all the basic blocks from LOOP into one or two super basic
+   blocks.  Replace PHI nodes with conditional modify expressions.  */

 
 static void
 combine_blocks (struct loop *loop)
 
 static void
 combine_blocks (struct loop *loop)


@@ -917,8 +911,8 @@ combine_blocks (struct loop *loop)
   /* Process phi nodes to prepare blocks for merge.  */
   process_phi_nodes (loop);
 
   /* Process phi nodes to prepare blocks for merge.  */
   process_phi_nodes (loop);
 

-  /* Merge basic blocks.  First remove all the edges in the loop, except
-     for those from the exit block.  */
+  /* Merge basic blocks: first remove all the edges in the loop,
+     except for those from the exit block.  */

   exit_bb = NULL;
   for (i = 0; i < orig_loop_num_nodes; i++)
     {
   exit_bb = NULL;
   for (i = 0; i < orig_loop_num_nodes; i++)
     {


@@ -948,7 +942,7 @@ combine_blocks (struct loop *loop)
     {
       if (exit_bb != loop->header)
        {
     {
       if (exit_bb != loop->header)
        {

-         /* Connect this node with loop header.  */
+         /* Connect this node to loop header.  */

          make_edge (loop->header, exit_bb, EDGE_FALLTHRU);
          set_immediate_dominator (CDI_DOMINATORS, exit_bb, loop->header);
        }
          make_edge (loop->header, exit_bb, EDGE_FALLTHRU);
          set_immediate_dominator (CDI_DOMINATORS, exit_bb, loop->header);
        }


@@ -963,7 +957,7 @@ combine_blocks (struct loop *loop)
     }
   else
     {
     }
   else
     {

-      /* If the loop does not have exit then reconnect header and latch.  */
+      /* If the loop does not have an exit, reconnect header and latch.  */

       make_edge (loop->header, loop->latch, EDGE_FALLTHRU);
       set_immediate_dominator (CDI_DOMINATORS, loop->latch, loop->header);
     }
       make_edge (loop->header, loop->latch, EDGE_FALLTHRU);
       set_immediate_dominator (CDI_DOMINATORS, loop->latch, loop->header);
     }


@@ -999,133 +993,86 @@ combine_blocks (struct loop *loop)
       delete_basic_block (bb);
     }
 
       delete_basic_block (bb);
     }
 

-  /* Now if possible, merge loop header and block with exit edge.
-     This reduces number of basic blocks to 2. Auto vectorizer addresses
-     loops with two nodes only.  FIXME: Use cleanup_tree_cfg().  */
+  /* If possible, merge loop header to the block with the exit edge.
+     This reduces the number of basic blocks to two, to please the
+     vectorizer that handles only loops with two nodes.
+
+     FIXME: Call cleanup_tree_cfg.  */

   if (exit_bb
       && exit_bb != loop->header
       && can_merge_blocks_p (loop->header, exit_bb))
     merge_blocks (loop->header, exit_bb);
 }
 
   if (exit_bb
       && exit_bb != loop->header
       && can_merge_blocks_p (loop->header, exit_bb))
     merge_blocks (loop->header, exit_bb);
 }
 

-/* Make a new temp variable of type TYPE. Add GIMPLE_ASSIGN to assign EXP
-   to the new variable.  */
-
-static gimple
-ifc_temp_var (tree type, tree exp)
-{
-  const char *name = "_ifc_";
-  tree var, new_name;
-  gimple stmt;
-
-  /* Create new temporary variable.  */
-  var = create_tmp_var (type, name);
-  add_referenced_var (var);
-
-  /* Build new statement to assign EXP to new variable.  */
-  stmt = gimple_build_assign (var, exp);
-
-  /* Get SSA name for the new variable and set make new statement
-     its definition statement.  */
-  new_name = make_ssa_name (var, stmt);
-  gimple_assign_set_lhs (stmt, new_name);
-  SSA_NAME_DEF_STMT (new_name) = stmt;
-  update_stmt (stmt);
-
-  return stmt;
-}
-
-
-/* Return TRUE iff, all pred blocks of BB are visited.
-   Bitmap VISITED keeps history of visited blocks.  */
+/* Main entry point: return true when LOOP is if-converted, otherwise
+   the loop remains unchanged.  */

 
 static bool
 
 static bool

-pred_blocks_visited_p (basic_block bb, bitmap *visited)
+tree_if_conversion (struct loop *loop)

 {
 {

-  edge e;
-  edge_iterator ei;
-  FOR_EACH_EDGE (e, ei, bb->preds)
-    if (!bitmap_bit_p (*visited, e->src->index))
-      return false;
-
-  return true;
-}
-
-/* Get body of a LOOP in suitable order for if-conversion.
-   It is caller's responsibility to deallocate basic block
-   list.  If-conversion suitable order is, BFS order with one
-   additional constraint. Select block in BFS block, if all
-   pred are already selected.  */
-
-static basic_block *
-get_loop_body_in_if_conv_order (const struct loop *loop)
-{
-  basic_block *blocks, *blocks_in_bfs_order;
-  basic_block bb;
-  bitmap visited;
-  unsigned int index = 0;
-  unsigned int visited_count = 0;
-
-  gcc_assert (loop->num_nodes);
-  gcc_assert (loop->latch != EXIT_BLOCK_PTR);
-
-  blocks = XCNEWVEC (basic_block, loop->num_nodes);
-  visited = BITMAP_ALLOC (NULL);
+  gimple_stmt_iterator itr;
+  unsigned int i;

 
 

-  blocks_in_bfs_order = get_loop_body_in_bfs_order (loop);
+  ifc_bbs = NULL;

 
 

-  index = 0;
-  while (index < loop->num_nodes)
+  /* If-conversion is not appropriate for all loops.  First, check if
+     the loop is if-convertible.  */
+  if (!if_convertible_loop_p (loop))

     {
     {

-      bb = blocks_in_bfs_order [index];
-
-      if (bb->flags & BB_IRREDUCIBLE_LOOP)
+      if (dump_file && (dump_flags & TDF_DETAILS))
+       fprintf (dump_file,"-------------------------\n");
+      if (ifc_bbs)

        {
        {

-         free (blocks_in_bfs_order);
-         BITMAP_FREE (visited);
-         free (blocks);
-         return NULL;
+         free (ifc_bbs);
+         ifc_bbs = NULL;

        }
        }

-      if (!bitmap_bit_p (visited, bb->index))
+      free_dominance_info (CDI_POST_DOMINATORS);
+      return false;
+    }
+
+  for (i = 0; i < loop->num_nodes; i++)
+    {
+      basic_block bb = ifc_bbs [i];
+      tree cond = (tree) bb->aux;
+
+      /* Process all the statements in this basic block.
+        Remove conditional expression, if any, and annotate
+        destination basic block(s) appropriately.  */
+      for (itr = gsi_start_bb (bb); !gsi_end_p (itr); /* empty */)

        {
        {

-         if (pred_blocks_visited_p (bb, &visited)
-             || bb == loop->header)
-           {
-             /* This block is now visited.  */
-             bitmap_set_bit (visited, bb->index);
-             blocks[visited_count++] = bb;
-           }
+         gimple t = gsi_stmt (itr);
+         cond = tree_if_convert_stmt (loop, t, cond, &itr);
+         if (!gsi_end_p (itr))
+           gsi_next (&itr);

        }
        }

-      index++;
-      if (index == loop->num_nodes
-         && visited_count != loop->num_nodes)
+
+      /* If current bb has only one successor, then consider it as an
+        unconditional goto.  */
+      if (single_succ_p (bb))

        {
        {

-         /* Not done yet.  */
-         index = 0;
+         basic_block bb_n = single_succ (bb);
+
+         /* The successor bb inherits the predicate of its
+            predecessor.  If there is no predicate in the predecessor
+            bb, then consider the successor bb as always executed.  */
+         if (cond == NULL_TREE)
+           cond = boolean_true_node;
+
+         add_to_predicate_list (bb_n, cond);

        }
     }
        }
     }

-  free (blocks_in_bfs_order);
-  BITMAP_FREE (visited);
-  return blocks;
-}
-
-/* Return true if one of the basic block BB edge is exit of LOOP.  */

 
 

-static bool
-bb_with_exit_edge_p (struct loop *loop, basic_block bb)
-{
-  edge e;
-  edge_iterator ei;
-  bool exit_edge_found = false;
+  /* Now, all statements are if-converted and basic blocks are
+     annotated appropriately.  Combine all the basic blocks into one
+     huge basic block.  */
+  combine_blocks (loop);

 
 

-  FOR_EACH_EDGE (e, ei, bb->succs)
-    if (loop_exit_edge_p (loop, e))
-      {
-       exit_edge_found = true;
-       break;
-      }
+  /* clean up */
+  clean_predicate_lists (loop);
+  free (ifc_bbs);
+  ifc_bbs = NULL;

 
 

-  return exit_edge_found;
+  return true;

 }
 
 /* Tree if-conversion pass management.  */
 }
 
 /* Tree if-conversion pass management.  */


@@ -1140,9 +1087,8 @@ main_tree_if_conversion (void)
     return 0;
 
   FOR_EACH_LOOP (li, loop, 0)
     return 0;
 
   FOR_EACH_LOOP (li, loop, 0)

-    {
-      tree_if_conversion (loop, true);
-    }
+    tree_if_conversion (loop);
+

   return 0;
 }
 
   return 0;
 }
 


@@ -1162,12 +1108,12 @@ struct gimple_opt_pass pass_if_conversion =
   NULL,                                        /* sub */
   NULL,                                        /* next */
   0,                                   /* static_pass_number */
   NULL,                                        /* sub */
   NULL,                                        /* next */
   0,                                   /* static_pass_number */

-  0,                                   /* tv_id */
-  PROP_cfg | PROP_ssa | PROP_alias,    /* properties_required */
+  TV_NONE,                             /* tv_id */
+  PROP_cfg | PROP_ssa,                 /* properties_required */

   0,                                   /* properties_provided */
   0,                                   /* properties_destroyed */
   0,                                   /* todo_flags_start */
   0,                                   /* properties_provided */
   0,                                   /* properties_destroyed */
   0,                                   /* todo_flags_start */

-  TODO_dump_func | TODO_verify_loops | TODO_verify_stmts | TODO_verify_flow
+  TODO_dump_func | TODO_verify_stmts | TODO_verify_flow

                                         /* todo_flags_finish */
  }
 };
                                         /* todo_flags_finish */
  }
 };