commit gcc-4.4.3 which is used to build gcc-4.4.3 Android toolchain in master.

The source is based on fsf gcc-4.4.3 and contains local patches which
are recorded in gcc-4.4.3/README.google.

Change-Id: Id8c6d6927df274ae9749196a1cc24dbd9abc9887

1 files changed, 2901 insertions, 0 deletions

diff --git a/gcc-4.4.3/gcc/modulo-sched.c b/gcc-4.4.3/gcc/modulo-sched.c
new file mode 100644
index 000000000..cb5d70d9c
--- /dev/null
+++ b/gcc-4.4.3/gcc/modulo-sched.c
@@ -0,0 +1,2901 @@
+/* Swing Modulo Scheduling implementation.
+   Copyright (C) 2004, 2005, 2006, 2007, 2008
+   Free Software Foundation, Inc.
+   Contributed by Ayal Zaks and Mustafa Hagog <zaks,mustafa@il.ibm.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 "toplev.h"
+#include "rtl.h"
+#include "tm_p.h"
+#include "hard-reg-set.h"
+#include "regs.h"
+#include "function.h"
+#include "flags.h"
+#include "insn-config.h"
+#include "insn-attr.h"
+#include "except.h"
+#include "toplev.h"
+#include "recog.h"
+#include "sched-int.h"
+#include "target.h"
+#include "cfglayout.h"
+#include "cfgloop.h"
+#include "cfghooks.h"
+#include "expr.h"
+#include "params.h"
+#include "gcov-io.h"
+#include "ddg.h"
+#include "timevar.h"
+#include "tree-pass.h"
+#include "dbgcnt.h"
+#include "basic-block.h"
+
+#ifdef INSN_SCHEDULING
+
+/* This file contains the implementation of the Swing Modulo Scheduler,
+   described in the following references:
+   [1] J. Llosa, A. Gonzalez, E. Ayguade, M. Valero., and J. Eckhardt.
+       Lifetime--sensitive modulo scheduling in a production environment.
+       IEEE Trans. on Comps., 50(3), March 2001
+   [2] J. Llosa, A. Gonzalez, E. Ayguade, and M. Valero.
+       Swing Modulo Scheduling: A Lifetime Sensitive Approach.
+       PACT '96 , pages 80-87, October 1996 (Boston - Massachusetts - USA).
+
+   The basic structure is:
+   1. Build a data-dependence graph (DDG) for each loop.
+   2. Use the DDG to order the insns of a loop (not in topological order
+      necessarily, but rather) trying to place each insn after all its
+      predecessors _or_ after all its successors.
+   3. Compute MII: a lower bound on the number of cycles to schedule the loop.
+   4. Use the ordering to perform list-scheduling of the loop:
+      1. Set II = MII.  We will try to schedule the loop within II cycles.
+      2. Try to schedule the insns one by one according to the ordering.
+	 For each insn compute an interval of cycles by considering already-
+	 scheduled preds and succs (and associated latencies); try to place
+	 the insn in the cycles of this window checking for potential
+	 resource conflicts (using the DFA interface).
+	 Note: this is different from the cycle-scheduling of schedule_insns;
+	 here the insns are not scheduled monotonically top-down (nor bottom-
+	 up).
+      3. If failed in scheduling all insns - bump II++ and try again, unless
+	 II reaches an upper bound MaxII, in which case report failure.
+   5. If we succeeded in scheduling the loop within II cycles, we now
+      generate prolog and epilog, decrease the counter of the loop, and
+      perform modulo variable expansion for live ranges that span more than
+      II cycles (i.e. use register copies to prevent a def from overwriting
+      itself before reaching the use).
+
+    SMS works with countable loops (1) whose control part can be easily
+    decoupled from the rest of the loop and (2) whose loop count can
+    be easily adjusted.  This is because we peel a constant number of
+    iterations into a prologue and epilogue for which we want to avoid
+    emitting the control part, and a kernel which is to iterate that
+    constant number of iterations less than the original loop.  So the
+    control part should be a set of insns clearly identified and having
+    its own iv, not otherwise used in the loop (at-least for now), which
+    initializes a register before the loop to the number of iterations.
+    Currently SMS relies on the do-loop pattern to recognize such loops,
+    where (1) the control part comprises of all insns defining and/or
+    using a certain 'count' register and (2) the loop count can be
+    adjusted by modifying this register prior to the loop.  
+    TODO: Rely on cfgloop analysis instead.  */
+
+/* This page defines partial-schedule structures and functions for
+   modulo scheduling.  */
+
+typedef struct partial_schedule *partial_schedule_ptr;
+typedef struct ps_insn *ps_insn_ptr;
+
+/* The minimum (absolute) cycle that a node of ps was scheduled in.  */
+#define PS_MIN_CYCLE(ps) (((partial_schedule_ptr)(ps))->min_cycle)
+
+/* The maximum (absolute) cycle that a node of ps was scheduled in.  */
+#define PS_MAX_CYCLE(ps) (((partial_schedule_ptr)(ps))->max_cycle)
+
+/* Perform signed modulo, always returning a non-negative value.  */
+#define SMODULO(x,y) ((x) % (y) < 0 ? ((x) % (y) + (y)) : (x) % (y))
+
+/* The number of different iterations the nodes in ps span, assuming
+   the stage boundaries are placed efficiently.  */
+#define PS_STAGE_COUNT(ps) ((PS_MAX_CYCLE (ps) - PS_MIN_CYCLE (ps) \
+			     + 1 + (ps)->ii - 1) / (ps)->ii)
+
+/* A single instruction in the partial schedule.  */
+struct ps_insn
+{
+  /* The corresponding DDG_NODE.  */
+  ddg_node_ptr node;
+
+  /* The (absolute) cycle in which the PS instruction is scheduled.
+     Same as SCHED_TIME (node).  */
+  int cycle;
+
+  /* The next/prev PS_INSN in the same row.  */
+  ps_insn_ptr next_in_row,
+	      prev_in_row;
+
+  /* The number of nodes in the same row that come after this node.  */
+  int row_rest_count;
+};
+
+/* Holds the partial schedule as an array of II rows.  Each entry of the
+   array points to a linked list of PS_INSNs, which represents the
+   instructions that are scheduled for that row.  */
+struct partial_schedule
+{
+  int ii;	/* Number of rows in the partial schedule.  */
+  int history;  /* Threshold for conflict checking using DFA.  */
+
+  /* rows[i] points to linked list of insns scheduled in row i (0<=i<ii).  */
+  ps_insn_ptr *rows;
+
+  /* The earliest absolute cycle of an insn in the partial schedule.  */
+  int min_cycle;
+
+  /* The latest absolute cycle of an insn in the partial schedule.  */
+  int max_cycle;
+
+  ddg_ptr g;	/* The DDG of the insns in the partial schedule.  */
+};
+
+/* We use this to record all the register replacements we do in
+   the kernel so we can undo SMS if it is not profitable.  */
+struct undo_replace_buff_elem
+{
+  rtx insn;
+  rtx orig_reg;
+  rtx new_reg;
+  struct undo_replace_buff_elem *next;
+};
+
+
+  
+static partial_schedule_ptr create_partial_schedule (int ii, ddg_ptr, int history);
+static void free_partial_schedule (partial_schedule_ptr);
+static void reset_partial_schedule (partial_schedule_ptr, int new_ii);
+void print_partial_schedule (partial_schedule_ptr, FILE *);
+static void verify_partial_schedule (partial_schedule_ptr, sbitmap);
+static ps_insn_ptr ps_add_node_check_conflicts (partial_schedule_ptr,
+						ddg_node_ptr node, int cycle,
+						sbitmap must_precede,
+						sbitmap must_follow);
+static void rotate_partial_schedule (partial_schedule_ptr, int);
+void set_row_column_for_ps (partial_schedule_ptr);
+static void ps_insert_empty_row (partial_schedule_ptr, int, sbitmap);
+static int compute_split_row (sbitmap, int, int, int, ddg_node_ptr);
+
+
+/* This page defines constants and structures for the modulo scheduling
+   driver.  */
+
+static int sms_order_nodes (ddg_ptr, int, int *, int *);
+static void set_node_sched_params (ddg_ptr);
+static partial_schedule_ptr sms_schedule_by_order (ddg_ptr, int, int, int *);
+static void permute_partial_schedule (partial_schedule_ptr, rtx);
+static void generate_prolog_epilog (partial_schedule_ptr, struct loop *,
+                                    rtx, rtx);
+static void duplicate_insns_of_cycles (partial_schedule_ptr,
+				       int, int, int, rtx);
+
+#define SCHED_ASAP(x) (((node_sched_params_ptr)(x)->aux.info)->asap)
+#define SCHED_TIME(x) (((node_sched_params_ptr)(x)->aux.info)->time)
+#define SCHED_FIRST_REG_MOVE(x) \
+	(((node_sched_params_ptr)(x)->aux.info)->first_reg_move)
+#define SCHED_NREG_MOVES(x) \
+	(((node_sched_params_ptr)(x)->aux.info)->nreg_moves)
+#define SCHED_ROW(x) (((node_sched_params_ptr)(x)->aux.info)->row)
+#define SCHED_STAGE(x) (((node_sched_params_ptr)(x)->aux.info)->stage)
+#define SCHED_COLUMN(x) (((node_sched_params_ptr)(x)->aux.info)->column)
+
+/* The scheduling parameters held for each node.  */
+typedef struct node_sched_params
+{
+  int asap;	/* A lower-bound on the absolute scheduling cycle.  */
+  int time;	/* The absolute scheduling cycle (time >= asap).  */
+
+  /* The following field (first_reg_move) is a pointer to the first
+     register-move instruction added to handle the modulo-variable-expansion
+     of the register defined by this node.  This register-move copies the
+     original register defined by the node.  */
+  rtx first_reg_move;
+
+  /* The number of register-move instructions added, immediately preceding
+     first_reg_move.  */
+  int nreg_moves;
+
+  int row;    /* Holds time % ii.  */
+  int stage;  /* Holds time / ii.  */
+
+  /* The column of a node inside the ps.  If nodes u, v are on the same row,
+     u will precede v if column (u) < column (v).  */
+  int column;
+} *node_sched_params_ptr;
+
+
+/* The following three functions are copied from the current scheduler
+   code in order to use sched_analyze() for computing the dependencies.
+   They are used when initializing the sched_info structure.  */
+static const char *
+sms_print_insn (const_rtx insn, int aligned ATTRIBUTE_UNUSED)
+{
+  static char tmp[80];
+
+  sprintf (tmp, "i%4d", INSN_UID (insn));
+  return tmp;
+}
+
+static void
+compute_jump_reg_dependencies (rtx insn ATTRIBUTE_UNUSED,
+			       regset cond_exec ATTRIBUTE_UNUSED,
+			       regset used ATTRIBUTE_UNUSED,
+			       regset set ATTRIBUTE_UNUSED)
+{
+}
+
+static struct common_sched_info_def sms_common_sched_info;
+
+static struct sched_deps_info_def sms_sched_deps_info =
+  {
+    compute_jump_reg_dependencies,
+    NULL, NULL, NULL, NULL, NULL, NULL, NULL, NULL, NULL, NULL,
+    NULL,
+    0, 0, 0
+  };
+
+static struct haifa_sched_info sms_sched_info =
+{
+  NULL,
+  NULL,
+  NULL,
+  NULL,
+  NULL,
+  sms_print_insn,
+  NULL,
+  NULL, NULL,
+  NULL, NULL,
+  0, 0,
+
+  NULL, NULL, NULL, 
+  0
+};
+
+/* Given HEAD and TAIL which are the first and last insns in a loop;
+   return the register which controls the loop.  Return zero if it has
+   more than one occurrence in the loop besides the control part or the
+   do-loop pattern is not of the form we expect.  */
+static rtx
+doloop_register_get (rtx head ATTRIBUTE_UNUSED, rtx tail ATTRIBUTE_UNUSED)
+{
+#ifdef HAVE_doloop_end
+  rtx reg, condition, insn, first_insn_not_to_check;
+
+  if (!JUMP_P (tail))
+    return NULL_RTX;
+
+  /* TODO: Free SMS's dependence on doloop_condition_get.  */
+  condition = doloop_condition_get (tail);
+  if (! condition)
+    return NULL_RTX;
+
+  if (REG_P (XEXP (condition, 0)))
+    reg = XEXP (condition, 0);
+  else if (GET_CODE (XEXP (condition, 0)) == PLUS
+	   && REG_P (XEXP (XEXP (condition, 0), 0)))
+    reg = XEXP (XEXP (condition, 0), 0);
+  else
+    gcc_unreachable ();
+
+  /* Check that the COUNT_REG has no other occurrences in the loop
+     until the decrement.  We assume the control part consists of
+     either a single (parallel) branch-on-count or a (non-parallel)
+     branch immediately preceded by a single (decrement) insn.  */
+  first_insn_not_to_check = (GET_CODE (PATTERN (tail)) == PARALLEL ? tail
+                             : PREV_INSN (tail));
+
+  for (insn = head; insn != first_insn_not_to_check; insn = NEXT_INSN (insn))
+    if (reg_mentioned_p (reg, insn))
+      {
+        if (dump_file)
+        {
+          fprintf (dump_file, "SMS count_reg found ");
+          print_rtl_single (dump_file, reg);
+          fprintf (dump_file, " outside control in insn:\n");
+          print_rtl_single (dump_file, insn);
+        }
+
+        return NULL_RTX;
+      }
+
+  return reg;
+#else
+  return NULL_RTX;
+#endif
+}
+
+/* Check if COUNT_REG is set to a constant in the PRE_HEADER block, so
+   that the number of iterations is a compile-time constant.  If so,
+   return the rtx that sets COUNT_REG to a constant, and set COUNT to
+   this constant.  Otherwise return 0.  */
+static rtx
+const_iteration_count (rtx count_reg, basic_block pre_header,
+		       HOST_WIDEST_INT * count)
+{
+  rtx insn;
+  rtx head, tail;
+
+  if (! pre_header)
+    return NULL_RTX;
+
+  get_ebb_head_tail (pre_header, pre_header, &head, &tail);
+
+  for (insn = tail; insn != PREV_INSN (head); insn = PREV_INSN (insn))
+    if (INSN_P (insn) && single_set (insn) &&
+	rtx_equal_p (count_reg, SET_DEST (single_set (insn))))
+      {
+	rtx pat = single_set (insn);
+
+	if (GET_CODE (SET_SRC (pat)) == CONST_INT)
+	  {
+	    *count = INTVAL (SET_SRC (pat));
+	    return insn;
+	  }
+
+	return NULL_RTX;
+      }
+
+  return NULL_RTX;
+}
+
+/* A very simple resource-based lower bound on the initiation interval.
+   ??? Improve the accuracy of this bound by considering the
+   utilization of various units.  */
+static int
+res_MII (ddg_ptr g)
+{
+  if (targetm.sched.sms_res_mii)
+    return targetm.sched.sms_res_mii (g); 
+  
+  return (g->num_nodes / issue_rate);
+}
+
+
+/* Points to the array that contains the sched data for each node.  */
+static node_sched_params_ptr node_sched_params;
+
+/* Allocate sched_params for each node and initialize it.  Assumes that
+   the aux field of each node contain the asap bound (computed earlier),
+   and copies it into the sched_params field.  */
+static void
+set_node_sched_params (ddg_ptr g)
+{
+  int i;
+
+  /* Allocate for each node in the DDG a place to hold the "sched_data".  */
+  /* Initialize ASAP/ALAP/HIGHT to zero.  */
+  node_sched_params = (node_sched_params_ptr)
+		       xcalloc (g->num_nodes,
+				sizeof (struct node_sched_params));
+
+  /* Set the pointer of the general data of the node to point to the
+     appropriate sched_params structure.  */
+  for (i = 0; i < g->num_nodes; i++)
+    {
+      /* Watch out for aliasing problems?  */
+      node_sched_params[i].asap = g->nodes[i].aux.count;
+      g->nodes[i].aux.info = &node_sched_params[i];
+    }
+}
+
+static void
+print_node_sched_params (FILE *file, int num_nodes, ddg_ptr g)
+{
+  int i;
+
+  if (! file)
+    return;
+  for (i = 0; i < num_nodes; i++)
+    {
+      node_sched_params_ptr nsp = &node_sched_params[i];
+      rtx reg_move = nsp->first_reg_move;
+      int j;
+
+      fprintf (file, "Node = %d; INSN = %d\n", i,
+	       (INSN_UID (g->nodes[i].insn)));
+      fprintf (file, " asap = %d:\n", nsp->asap);
+      fprintf (file, " time = %d:\n", nsp->time);
+      fprintf (file, " nreg_moves = %d:\n", nsp->nreg_moves);
+      for (j = 0; j < nsp->nreg_moves; j++)
+	{
+	  fprintf (file, " reg_move = ");
+	  print_rtl_single (file, reg_move);
+	  reg_move = PREV_INSN (reg_move);
+	}
+    }
+}
+
+/*
+   Breaking intra-loop register anti-dependences:
+   Each intra-loop register anti-dependence implies a cross-iteration true
+   dependence of distance 1. Therefore, we can remove such false dependencies
+   and figure out if the partial schedule broke them by checking if (for a
+   true-dependence of distance 1): SCHED_TIME (def) < SCHED_TIME (use) and
+   if so generate a register move.   The number of such moves is equal to:
+              SCHED_TIME (use) - SCHED_TIME (def)       { 0 broken
+   nreg_moves = ----------------------------------- + 1 - {   dependence.
+                            ii                          { 1 if not.
+*/
+static struct undo_replace_buff_elem *
+generate_reg_moves (partial_schedule_ptr ps, bool rescan)
+{
+  ddg_ptr g = ps->g;
+  int ii = ps->ii;
+  int i;
+  struct undo_replace_buff_elem *reg_move_replaces = NULL;
+
+  for (i = 0; i < g->num_nodes; i++)
+    {
+      ddg_node_ptr u = &g->nodes[i];
+      ddg_edge_ptr e;
+      int nreg_moves = 0, i_reg_move;
+      sbitmap *uses_of_defs;
+      rtx last_reg_move;
+      rtx prev_reg, old_reg;
+
+      /* Compute the number of reg_moves needed for u, by looking at life
+	 ranges started at u (excluding self-loops).  */
+      for (e = u->out; e; e = e->next_out)
+	if (e->type == TRUE_DEP && e->dest != e->src)
+	  {
+	    int nreg_moves4e = (SCHED_TIME (e->dest) - SCHED_TIME (e->src)) / ii;
+
+            if (e->distance == 1)
+              nreg_moves4e = (SCHED_TIME (e->dest) - SCHED_TIME (e->src) + ii) / ii;
+
+	    /* If dest precedes src in the schedule of the kernel, then dest
+	       will read before src writes and we can save one reg_copy.  */
+	    if (SCHED_ROW (e->dest) == SCHED_ROW (e->src)
+		&& SCHED_COLUMN (e->dest) < SCHED_COLUMN (e->src))
+	      nreg_moves4e--;
+
+	    nreg_moves = MAX (nreg_moves, nreg_moves4e);
+	  }
+
+      if (nreg_moves == 0)
+	continue;
+
+      /* Every use of the register defined by node may require a different
+	 copy of this register, depending on the time the use is scheduled.
+	 Set a bitmap vector, telling which nodes use each copy of this
+	 register.  */
+      uses_of_defs = sbitmap_vector_alloc (nreg_moves, g->num_nodes);
+      sbitmap_vector_zero (uses_of_defs, nreg_moves);
+      for (e = u->out; e; e = e->next_out)
+	if (e->type == TRUE_DEP && e->dest != e->src)
+	  {
+	    int dest_copy = (SCHED_TIME (e->dest) - SCHED_TIME (e->src)) / ii;
+
+	    if (e->distance == 1)
+	      dest_copy = (SCHED_TIME (e->dest) - SCHED_TIME (e->src) + ii) / ii;
+
+	    if (SCHED_ROW (e->dest) == SCHED_ROW (e->src)
+		&& SCHED_COLUMN (e->dest) < SCHED_COLUMN (e->src))
+	      dest_copy--;
+
+	    if (dest_copy)
+	      SET_BIT (uses_of_defs[dest_copy - 1], e->dest->cuid);
+	  }
+
+      /* Now generate the reg_moves, attaching relevant uses to them.  */
+      SCHED_NREG_MOVES (u) = nreg_moves;
+      old_reg = prev_reg = copy_rtx (SET_DEST (single_set (u->insn)));
+      /* Insert the reg-moves right before the notes which precede
+         the insn they relates to.  */
+      last_reg_move = u->first_note;
+
+      for (i_reg_move = 0; i_reg_move < nreg_moves; i_reg_move++)
+	{
+	  unsigned int i_use = 0;
+	  rtx new_reg = gen_reg_rtx (GET_MODE (prev_reg));
+	  rtx reg_move = gen_move_insn (new_reg, prev_reg);
+	  sbitmap_iterator sbi;
+
+	  add_insn_before (reg_move, last_reg_move, NULL);
+	  last_reg_move = reg_move;
+
+	  if (!SCHED_FIRST_REG_MOVE (u))
+	    SCHED_FIRST_REG_MOVE (u) = reg_move;
+
+	  EXECUTE_IF_SET_IN_SBITMAP (uses_of_defs[i_reg_move], 0, i_use, sbi)
+	    {
+	      struct undo_replace_buff_elem *rep;
+
+	      rep = (struct undo_replace_buff_elem *)
+		    xcalloc (1, sizeof (struct undo_replace_buff_elem));
+	      rep->insn = g->nodes[i_use].insn;
+	      rep->orig_reg = old_reg;
+	      rep->new_reg = new_reg;
+
+	      if (! reg_move_replaces)
+		reg_move_replaces = rep;
+	      else
+		{
+		  rep->next = reg_move_replaces;
+		  reg_move_replaces = rep;
+		}
+
+	      replace_rtx (g->nodes[i_use].insn, old_reg, new_reg);
+	      if (rescan)
+		df_insn_rescan (g->nodes[i_use].insn);
+	    }
+
+	  prev_reg = new_reg;
+	}
+      sbitmap_vector_free (uses_of_defs);
+    }
+  return reg_move_replaces;
+}
+
+/* Free memory allocated for the undo buffer.  */
+static void
+free_undo_replace_buff (struct undo_replace_buff_elem *reg_move_replaces)
+{
+
+  while (reg_move_replaces)
+    {
+      struct undo_replace_buff_elem *rep = reg_move_replaces;
+
+      reg_move_replaces = reg_move_replaces->next;
+      free (rep);
+    }
+}
+
+/* Bump the SCHED_TIMEs of all nodes to start from zero.  Set the values
+   of SCHED_ROW and SCHED_STAGE.  */
+static void
+normalize_sched_times (partial_schedule_ptr ps)
+{
+  int row;
+  int amount = PS_MIN_CYCLE (ps);
+  int ii = ps->ii;
+  ps_insn_ptr crr_insn;
+
+  for (row = 0; row < ii; row++)
+    for (crr_insn = ps->rows[row]; crr_insn; crr_insn = crr_insn->next_in_row)
+      {
+	ddg_node_ptr u = crr_insn->node;
+	int normalized_time = SCHED_TIME (u) - amount;
+
+	if (dump_file)
+	  fprintf (dump_file, "crr_insn->node=%d, crr_insn->cycle=%d,\
+		   min_cycle=%d\n", crr_insn->node->cuid, SCHED_TIME
+		   (u), ps->min_cycle);
+	gcc_assert (SCHED_TIME (u) >= ps->min_cycle);
+	gcc_assert (SCHED_TIME (u) <= ps->max_cycle);
+	SCHED_TIME (u) = normalized_time;
+	SCHED_ROW (u) = normalized_time % ii;
+	SCHED_STAGE (u) = normalized_time / ii;
+      }
+}
+
+/* Set SCHED_COLUMN of each node according to its position in PS.  */
+static void
+set_columns_for_ps (partial_schedule_ptr ps)
+{
+  int row;
+
+  for (row = 0; row < ps->ii; row++)
+    {
+      ps_insn_ptr cur_insn = ps->rows[row];
+      int column = 0;
+
+      for (; cur_insn; cur_insn = cur_insn->next_in_row)
+	SCHED_COLUMN (cur_insn->node) = column++;
+    }
+}
+
+/* Permute the insns according to their order in PS, from row 0 to
+   row ii-1, and position them right before LAST.  This schedules
+   the insns of the loop kernel.  */
+static void
+permute_partial_schedule (partial_schedule_ptr ps, rtx last)
+{
+  int ii = ps->ii;
+  int row;
+  ps_insn_ptr ps_ij;
+
+  for (row = 0; row < ii ; row++)
+    for (ps_ij = ps->rows[row]; ps_ij; ps_ij = ps_ij->next_in_row)
+      if (PREV_INSN (last) != ps_ij->node->insn)
+      	reorder_insns_nobb (ps_ij->node->first_note, ps_ij->node->insn,
+			    PREV_INSN (last));
+}
+
+static void
+duplicate_insns_of_cycles (partial_schedule_ptr ps, int from_stage,
+			   int to_stage, int for_prolog, rtx count_reg)
+{
+  int row;
+  ps_insn_ptr ps_ij;
+
+  for (row = 0; row < ps->ii; row++)
+    for (ps_ij = ps->rows[row]; ps_ij; ps_ij = ps_ij->next_in_row)
+      {
+	ddg_node_ptr u_node = ps_ij->node;
+	int j, i_reg_moves;
+	rtx reg_move = NULL_RTX;
+
+        /* Do not duplicate any insn which refers to count_reg as it
+           belongs to the control part.
+           TODO: This should be done by analyzing the control part of
+           the loop.  */
+        if (reg_mentioned_p (count_reg, u_node->insn))
+          continue;
+
+	if (for_prolog)
+	  {
+	    /* SCHED_STAGE (u_node) >= from_stage == 0.  Generate increasing
+	       number of reg_moves starting with the second occurrence of
+	       u_node, which is generated if its SCHED_STAGE <= to_stage.  */
+	    i_reg_moves = to_stage - SCHED_STAGE (u_node) + 1;
+	    i_reg_moves = MAX (i_reg_moves, 0);
+	    i_reg_moves = MIN (i_reg_moves, SCHED_NREG_MOVES (u_node));
+
+	    /* The reg_moves start from the *first* reg_move backwards.  */
+	    if (i_reg_moves)
+	      {
+		reg_move = SCHED_FIRST_REG_MOVE (u_node);
+		for (j = 1; j < i_reg_moves; j++)
+		  reg_move = PREV_INSN (reg_move);
+	      }
+	  }
+	else /* It's for the epilog.  */
+	  {
+	    /* SCHED_STAGE (u_node) <= to_stage.  Generate all reg_moves,
+	       starting to decrease one stage after u_node no longer occurs;
+	       that is, generate all reg_moves until
+	       SCHED_STAGE (u_node) == from_stage - 1.  */
+	    i_reg_moves = SCHED_NREG_MOVES (u_node)
+	    	       - (from_stage - SCHED_STAGE (u_node) - 1);
+	    i_reg_moves = MAX (i_reg_moves, 0);
+	    i_reg_moves = MIN (i_reg_moves, SCHED_NREG_MOVES (u_node));
+
+	    /* The reg_moves start from the *last* reg_move forwards.  */
+	    if (i_reg_moves)
+	      {
+		reg_move = SCHED_FIRST_REG_MOVE (u_node);
+		for (j = 1; j < SCHED_NREG_MOVES (u_node); j++)
+		  reg_move = PREV_INSN (reg_move);
+	      }
+	  }
+
+	for (j = 0; j < i_reg_moves; j++, reg_move = NEXT_INSN (reg_move))
+	  emit_insn (copy_rtx (PATTERN (reg_move)));
+	if (SCHED_STAGE (u_node) >= from_stage
+	    && SCHED_STAGE (u_node) <= to_stage)
+	  duplicate_insn_chain (u_node->first_note, u_node->insn);
+      }
+}
+
+
+/* Generate the instructions (including reg_moves) for prolog & epilog.  */
+static void
+generate_prolog_epilog (partial_schedule_ptr ps, struct loop *loop,
+                        rtx count_reg, rtx count_init)
+{
+  int i;
+  int last_stage = PS_STAGE_COUNT (ps) - 1;
+  edge e;
+  
+  /* Generate the prolog, inserting its insns on the loop-entry edge.  */
+  start_sequence ();
+
+  if (!count_init)
+    {
+      /* Generate instructions at the beginning of the prolog to
+         adjust the loop count by STAGE_COUNT.  If loop count is constant
+         (count_init), this constant is adjusted by STAGE_COUNT in
+         generate_prolog_epilog function.  */
+      rtx sub_reg = NULL_RTX;
+
+      sub_reg = expand_simple_binop (GET_MODE (count_reg), MINUS,
+                                     count_reg, GEN_INT (last_stage),
+                                     count_reg, 1, OPTAB_DIRECT);
+      gcc_assert (REG_P (sub_reg));
+      if (REGNO (sub_reg) != REGNO (count_reg))
+        emit_move_insn (count_reg, sub_reg);
+    }
+
+  for (i = 0; i < last_stage; i++)
+    duplicate_insns_of_cycles (ps, 0, i, 1, count_reg);
+  
+  /* Put the prolog on the entry edge.  */
+  e = loop_preheader_edge (loop);
+  split_edge_and_insert (e, get_insns ());
+
+  end_sequence ();
+
+  /* Generate the epilog, inserting its insns on the loop-exit edge.  */
+  start_sequence ();
+
+  for (i = 0; i < last_stage; i++)
+    duplicate_insns_of_cycles (ps, i + 1, last_stage, 0, count_reg);
+  
+  /* Put the epilogue on the exit edge.  */
+  gcc_assert (single_exit (loop));
+  e = single_exit (loop);
+  split_edge_and_insert (e, get_insns ());
+  end_sequence ();
+}
+
+/* Return true if all the BBs of the loop are empty except the
+   loop header.  */
+static bool
+loop_single_full_bb_p (struct loop *loop)
+{
+  unsigned i;
+  basic_block *bbs = get_loop_body (loop);
+
+  for (i = 0; i < loop->num_nodes ; i++)
+    {
+      rtx head, tail;
+      bool empty_bb = true;
+
+      if (bbs[i] == loop->header)
+        continue;
+
+      /* Make sure that basic blocks other than the header
+         have only notes labels or jumps.  */
+      get_ebb_head_tail (bbs[i], bbs[i], &head, &tail);
+      for (; head != NEXT_INSN (tail); head = NEXT_INSN (head))
+        {
+          if (NOTE_P (head) || LABEL_P (head)
+ 	      || (INSN_P (head) && JUMP_P (head)))
+ 	    continue;
+ 	  empty_bb = false;
+ 	  break;
+        }
+
+      if (! empty_bb)
+        {
+          free (bbs);
+          return false;
+        }
+    }
+  free (bbs);
+  return true;
+}
+
+/* A simple loop from SMS point of view; it is a loop that is composed of
+   either a single basic block or two BBs - a header and a latch.  */
+#define SIMPLE_SMS_LOOP_P(loop) ((loop->num_nodes < 3 ) 		    \
+				  && (EDGE_COUNT (loop->latch->preds) == 1) \
+                                  && (EDGE_COUNT (loop->latch->succs) == 1))
+
+/* Return true if the loop is in its canonical form and false if not.
+   i.e. SIMPLE_SMS_LOOP_P and have one preheader block, and single exit.  */
+static bool
+loop_canon_p (struct loop *loop)
+{
+
+  if (loop->inner || !loop_outer (loop))
+  {
+    if (dump_file)
+      fprintf (dump_file, "SMS loop inner or !loop_outer\n");
+    return false;
+  }
+
+  if (!single_exit (loop))
+    {
+      if (dump_file)
+	{
+	  rtx insn = BB_END (loop->header);
+ 
+	  fprintf (dump_file, "SMS loop many exits ");
+	  	  fprintf (dump_file, " %s %d (file, line)\n",
+			   insn_file (insn), insn_line (insn));
+	}
+      return false;
+    }
+
+  if (! SIMPLE_SMS_LOOP_P (loop) && ! loop_single_full_bb_p (loop))
+    {
+      if (dump_file)
+	{
+	  rtx insn = BB_END (loop->header);
+ 
+	  fprintf (dump_file, "SMS loop many BBs. ");
+	  fprintf (dump_file, " %s %d (file, line)\n",
+		   insn_file (insn), insn_line (insn));
+	}
+      return false;
+    }
+
+    return true;
+}
+
+/* If there are more than one entry for the loop,
+   make it one by splitting the first entry edge and
+   redirecting the others to the new BB.  */
+static void
+canon_loop (struct loop *loop)
+{
+  edge e;
+  edge_iterator i;
+
+  /* Avoid annoying special cases of edges going to exit
+     block.  */
+  FOR_EACH_EDGE (e, i, EXIT_BLOCK_PTR->preds)
+    if ((e->flags & EDGE_FALLTHRU) && (EDGE_COUNT (e->src->succs) > 1))
+      split_edge (e);
+
+  if (loop->latch == loop->header
+      || EDGE_COUNT (loop->latch->succs) > 1)
+    {
+      FOR_EACH_EDGE (e, i, loop->header->preds)
+        if (e->src == loop->latch)
+          break;
+      split_edge (e);
+    }
+}
+
+/* Setup infos.  */
+static void
+setup_sched_infos (void)
+{
+  memcpy (&sms_common_sched_info, &haifa_common_sched_info,
+	  sizeof (sms_common_sched_info));
+  sms_common_sched_info.sched_pass_id = SCHED_SMS_PASS;
+  common_sched_info = &sms_common_sched_info;
+
+  sched_deps_info = &sms_sched_deps_info;
+  current_sched_info = &sms_sched_info;
+}
+
+/* Probability in % that the sms-ed loop rolls enough so that optimized
+   version may be entered.  Just a guess.  */
+#define PROB_SMS_ENOUGH_ITERATIONS 80
+
+/* Used to calculate the upper bound of ii.  */
+#define MAXII_FACTOR 2
+
+/* Main entry point, perform SMS scheduling on the loops of the function
+   that consist of single basic blocks.  */
+static void
+sms_schedule (void)
+{
+  rtx insn;
+  ddg_ptr *g_arr, g;
+  int * node_order;
+  int maxii, max_asap;
+  loop_iterator li;
+  partial_schedule_ptr ps;
+  basic_block bb = NULL;
+  struct loop *loop;
+  basic_block condition_bb = NULL;
+  edge latch_edge;
+  gcov_type trip_count = 0;
+
+  loop_optimizer_init (LOOPS_HAVE_PREHEADERS
+		       | LOOPS_HAVE_RECORDED_EXITS);
+  if (number_of_loops () <= 1)
+    {
+      loop_optimizer_finalize ();
+      return;  /* There are no loops to schedule.  */
+    }
+
+  /* Initialize issue_rate.  */
+  if (targetm.sched.issue_rate)
+    {
+      int temp = reload_completed;
+
+      reload_completed = 1;
+      issue_rate = targetm.sched.issue_rate ();
+      reload_completed = temp;
+    }
+  else
+    issue_rate = 1;
+
+  /* Initialize the scheduler.  */
+  setup_sched_infos ();
+  haifa_sched_init ();
+
+  /* Allocate memory to hold the DDG array one entry for each loop.
+     We use loop->num as index into this array.  */
+  g_arr = XCNEWVEC (ddg_ptr, number_of_loops ());
+
+  if (dump_file)
+  {
+    fprintf (dump_file, "\n\nSMS analysis phase\n");
+    fprintf (dump_file, "===================\n\n");
+  }
+
+  /* Build DDGs for all the relevant loops and hold them in G_ARR
+     indexed by the loop index.  */
+  FOR_EACH_LOOP (li, loop, 0)
+    {
+      rtx head, tail;
+      rtx count_reg;
+
+      /* For debugging.  */
+      if (dbg_cnt (sms_sched_loop) == false)
+        {
+          if (dump_file)
+            fprintf (dump_file, "SMS reached max limit... \n");
+
+          break;
+        }
+
+      if (dump_file)
+      {
+         rtx insn = BB_END (loop->header);
+
+         fprintf (dump_file, "SMS loop num: %d, file: %s, line: %d\n",
+                  loop->num, insn_file (insn), insn_line (insn));
+
+      }
+
+      if (! loop_canon_p (loop))
+        continue;
+
+      if (! loop_single_full_bb_p (loop))
+      {
+        if (dump_file)
+          fprintf (dump_file, "SMS not loop_single_full_bb_p\n");
+	continue;
+      }
+
+      bb = loop->header;
+
+      get_ebb_head_tail (bb, bb, &head, &tail);
+      latch_edge = loop_latch_edge (loop);
+      gcc_assert (single_exit (loop));
+      if (single_exit (loop)->count)
+	trip_count = latch_edge->count / single_exit (loop)->count;
+
+      /* Perform SMS only on loops that their average count is above threshold.  */
+
+      if ( latch_edge->count
+          && (latch_edge->count < single_exit (loop)->count * SMS_LOOP_AVERAGE_COUNT_THRESHOLD))
+	{
+	  if (dump_file)
+	    {
+	      fprintf (dump_file, " %s %d (file, line)\n",
+		       insn_file (tail), insn_line (tail));
+	      fprintf (dump_file, "SMS single-bb-loop\n");
+	      if (profile_info_available_p ())
+	    	{
+	      	  fprintf (dump_file, "SMS loop-count ");
+	      	  fprintf (dump_file, HOST_WIDEST_INT_PRINT_DEC,
+	             	   (HOST_WIDEST_INT) bb->count);
+	      	  fprintf (dump_file, "\n");
+                  fprintf (dump_file, "SMS trip-count ");
+                  fprintf (dump_file, HOST_WIDEST_INT_PRINT_DEC,
+                           (HOST_WIDEST_INT) trip_count);
+                  fprintf (dump_file, "\n");
+	      	  fprintf (dump_file, "SMS profile-sum-max ");
+	      	  fprintf (dump_file, HOST_WIDEST_INT_PRINT_DEC,
+	          	   (HOST_WIDEST_INT) profile_info->sum_max);
+	      	  fprintf (dump_file, "\n");
+	    	}
+	    }
+          continue;
+        }
+
+      /* Make sure this is a doloop.  */
+      if ( !(count_reg = doloop_register_get (head, tail)))
+      {
+        if (dump_file)
+          fprintf (dump_file, "SMS doloop_register_get failed\n");
+	continue;
+      }
+
+      /* Don't handle BBs with calls or barriers, or !single_set insns,
+         or auto-increment insns (to avoid creating invalid reg-moves
+         for the auto-increment insns).  
+         ??? Should handle auto-increment insns.
+         ??? Should handle insns defining subregs.  */
+     for (insn = head; insn != NEXT_INSN (tail); insn = NEXT_INSN (insn))
+      {
+         rtx set;
+
+        if (CALL_P (insn)
+            || BARRIER_P (insn)
+            || (INSN_P (insn) && !JUMP_P (insn)
+                && !single_set (insn) && GET_CODE (PATTERN (insn)) != USE)
+            || (FIND_REG_INC_NOTE (insn, NULL_RTX) != 0)
+            || (INSN_P (insn) && (set = single_set (insn))
+                && GET_CODE (SET_DEST (set)) == SUBREG))
+        break;
+      }
+
+      if (insn != NEXT_INSN (tail))
+	{
+	  if (dump_file)
+	    {
+	      if (CALL_P (insn))
+		fprintf (dump_file, "SMS loop-with-call\n");
+	      else if (BARRIER_P (insn))
+		fprintf (dump_file, "SMS loop-with-barrier\n");
+              else if (FIND_REG_INC_NOTE (insn, NULL_RTX) != 0)
+                fprintf (dump_file, "SMS reg inc\n");
+              else if ((INSN_P (insn) && !JUMP_P (insn)
+                && !single_set (insn) && GET_CODE (PATTERN (insn)) != USE))
+                fprintf (dump_file, "SMS loop-with-not-single-set\n");
+              else
+               fprintf (dump_file, "SMS loop with subreg in lhs\n");
+	      print_rtl_single (dump_file, insn);
+	    }
+
+	  continue;
+	}
+
+      if (! (g = create_ddg (bb, 0)))
+        {
+          if (dump_file)
+	    fprintf (dump_file, "SMS create_ddg failed\n");
+	  continue;
+        }
+
+      g_arr[loop->num] = g;
+      if (dump_file)
+        fprintf (dump_file, "...OK\n");
+
+    }
+  if (dump_file)
+  {
+    fprintf (dump_file, "\nSMS transformation phase\n");
+    fprintf (dump_file, "=========================\n\n");
+  }
+
+  /* We don't want to perform SMS on new loops - created by versioning.  */
+  FOR_EACH_LOOP (li, loop, 0)
+    {
+      rtx head, tail;
+      rtx count_reg, count_init;
+      int mii, rec_mii;
+      unsigned stage_count = 0;
+      HOST_WIDEST_INT loop_count = 0;
+
+      if (! (g = g_arr[loop->num]))
+        continue;
+
+      if (dump_file)
+      {
+         rtx insn = BB_END (loop->header);
+
+         fprintf (dump_file, "SMS loop num: %d, file: %s, line: %d\n",
+                  loop->num, insn_file (insn), insn_line (insn));
+
+         print_ddg (dump_file, g);
+      }
+
+      get_ebb_head_tail (loop->header, loop->header, &head, &tail);
+
+      latch_edge = loop_latch_edge (loop);
+      gcc_assert (single_exit (loop));
+      if (single_exit (loop)->count)
+	trip_count = latch_edge->count / single_exit (loop)->count;
+
+      if (dump_file)
+	{
+	  fprintf (dump_file, " %s %d (file, line)\n",
+		   insn_file (tail), insn_line (tail));
+	  fprintf (dump_file, "SMS single-bb-loop\n");
+	  if (profile_info_available_p ())
+	    {
+	      fprintf (dump_file, "SMS loop-count ");
+	      fprintf (dump_file, HOST_WIDEST_INT_PRINT_DEC,
+	               (HOST_WIDEST_INT) bb->count);
+	      fprintf (dump_file, "\n");
+	      fprintf (dump_file, "SMS profile-sum-max ");
+	      fprintf (dump_file, HOST_WIDEST_INT_PRINT_DEC,
+	               (HOST_WIDEST_INT) profile_info->sum_max);
+	      fprintf (dump_file, "\n");
+	    }
+	  fprintf (dump_file, "SMS doloop\n");
+	  fprintf (dump_file, "SMS built-ddg %d\n", g->num_nodes);
+          fprintf (dump_file, "SMS num-loads %d\n", g->num_loads);
+          fprintf (dump_file, "SMS num-stores %d\n", g->num_stores);
+	}
+
+
+      /* In case of th loop have doloop register it gets special
+	 handling.  */
+      count_init = NULL_RTX;
+      if ((count_reg = doloop_register_get (head, tail)))
+	{
+	  basic_block pre_header;
+
+	  pre_header = loop_preheader_edge (loop)->src;
+	  count_init = const_iteration_count (count_reg, pre_header,
+					      &loop_count);
+	}
+      gcc_assert (count_reg);
+
+      if (dump_file && count_init)
+        {
+          fprintf (dump_file, "SMS const-doloop ");
+          fprintf (dump_file, HOST_WIDEST_INT_PRINT_DEC,
+		     loop_count);
+          fprintf (dump_file, "\n");
+        }
+
+      node_order = XNEWVEC (int, g->num_nodes);
+
+      mii = 1; /* Need to pass some estimate of mii.  */
+      rec_mii = sms_order_nodes (g, mii, node_order, &max_asap);
+      mii = MAX (res_MII (g), rec_mii);
+      maxii = MAX (max_asap, MAXII_FACTOR * mii);
+
+      if (dump_file)
+	fprintf (dump_file, "SMS iis %d %d %d (rec_mii, mii, maxii)\n",
+		 rec_mii, mii, maxii);
+
+      /* After sms_order_nodes and before sms_schedule_by_order, to copy over
+	 ASAP.  */
+      set_node_sched_params (g);
+
+      ps = sms_schedule_by_order (g, mii, maxii, node_order);
+
+      if (ps)
+	stage_count = PS_STAGE_COUNT (ps);
+
+      /* Stage count of 1 means that there is no interleaving between
+         iterations, let the scheduling passes do the job.  */
+      if (stage_count < 1
+	  || (count_init && (loop_count <= stage_count))
+	  || ((flag_branch_probabilities || flag_sample_profile)
+              && (trip_count <= stage_count)))
+	{
+	  if (dump_file)
+	    {
+	      fprintf (dump_file, "SMS failed... \n");
+	      fprintf (dump_file, "SMS sched-failed (stage-count=%d, loop-count=", stage_count);
+	      fprintf (dump_file, HOST_WIDEST_INT_PRINT_DEC, loop_count);
+	      fprintf (dump_file, ", trip-count=");
+	      fprintf (dump_file, HOST_WIDEST_INT_PRINT_DEC, trip_count);
+	      fprintf (dump_file, ")\n");
+	    }
+	  continue;
+	}
+      else
+	{
+	  struct undo_replace_buff_elem *reg_move_replaces;
+
+	  if (dump_file)
+	    {
+	      fprintf (dump_file,
+		       "SMS succeeded %d %d (with ii, sc)\n", ps->ii,
+		       stage_count);
+	      print_partial_schedule (ps, dump_file);
+	      fprintf (dump_file,
+		       "SMS Branch (%d) will later be scheduled at cycle %d.\n",
+		       g->closing_branch->cuid, PS_MIN_CYCLE (ps) - 1);
+	    }
+
+	  /* Set the stage boundaries.  If the DDG is built with closing_branch_deps,
+	     the closing_branch was scheduled and should appear in the last (ii-1)
+	     row.  Otherwise, we are free to schedule the branch, and we let nodes
+	     that were scheduled at the first PS_MIN_CYCLE cycle appear in the first
+	     row; this should reduce stage_count to minimum.  
+             TODO: Revisit the issue of scheduling the insns of the
+             control part relative to the branch when the control part
+             has more than one insn.  */
+	  normalize_sched_times (ps);
+	  rotate_partial_schedule (ps, PS_MIN_CYCLE (ps));
+	  set_columns_for_ps (ps);
+	  
+	  canon_loop (loop);
+
+          /* case the BCT count is not known , Do loop-versioning */
+	  if (count_reg && ! count_init)
+            {
+	      rtx comp_rtx = gen_rtx_fmt_ee (GT, VOIDmode, count_reg,
+	  				     GEN_INT(stage_count));
+	      unsigned prob = (PROB_SMS_ENOUGH_ITERATIONS
+			       * REG_BR_PROB_BASE) / 100;
+
+	      loop_version (loop, comp_rtx, &condition_bb,
+	  		    prob, prob, REG_BR_PROB_BASE - prob,
+			    true);
+	     }
+
+	  /* Set new iteration count of loop kernel.  */
+          if (count_reg && count_init)
+	    SET_SRC (single_set (count_init)) = GEN_INT (loop_count
+						     - stage_count + 1);
+
+	  /* Now apply the scheduled kernel to the RTL of the loop.  */
+	  permute_partial_schedule (ps, g->closing_branch->first_note);
+
+          /* Mark this loop as software pipelined so the later
+	     scheduling passes doesn't touch it.  */
+	  if (! flag_resched_modulo_sched)
+	    g->bb->flags |= BB_DISABLE_SCHEDULE;
+	  /* The life-info is not valid any more.  */
+	  df_set_bb_dirty (g->bb);
+
+	  reg_move_replaces = generate_reg_moves (ps, true);
+	  if (dump_file)
+	    print_node_sched_params (dump_file, g->num_nodes, g);
+	  /* Generate prolog and epilog.  */
+          generate_prolog_epilog (ps, loop, count_reg, count_init);
+ 
+	  free_undo_replace_buff (reg_move_replaces);
+	}
+
+      free_partial_schedule (ps);
+      free (node_sched_params);
+      free (node_order);
+      free_ddg (g);
+    }
+
+  free (g_arr);
+
+  /* Release scheduler data, needed until now because of DFA.  */
+  haifa_sched_finish ();
+  loop_optimizer_finalize ();
+}
+
+/* The SMS scheduling algorithm itself
+   -----------------------------------
+   Input: 'O' an ordered list of insns of a loop.
+   Output: A scheduling of the loop - kernel, prolog, and epilogue.
+
+   'Q' is the empty Set
+   'PS' is the partial schedule; it holds the currently scheduled nodes with
+	their cycle/slot.
+   'PSP' previously scheduled predecessors.
+   'PSS' previously scheduled successors.
+   't(u)' the cycle where u is scheduled.
+   'l(u)' is the latency of u.
+   'd(v,u)' is the dependence distance from v to u.
+   'ASAP(u)' the earliest time at which u could be scheduled as computed in
+	     the node ordering phase.
+   'check_hardware_resources_conflicts(u, PS, c)'
+			     run a trace around cycle/slot through DFA model
+			     to check resource conflicts involving instruction u
+			     at cycle c given the partial schedule PS.
+   'add_to_partial_schedule_at_time(u, PS, c)'
+			     Add the node/instruction u to the partial schedule
+			     PS at time c.
+   'calculate_register_pressure(PS)'
+			     Given a schedule of instructions, calculate the register
+			     pressure it implies.  One implementation could be the
+			     maximum number of overlapping live ranges.
+   'maxRP' The maximum allowed register pressure, it is usually derived from the number
+	   registers available in the hardware.
+
+   1. II = MII.
+   2. PS = empty list
+   3. for each node u in O in pre-computed order
+   4.   if (PSP(u) != Q && PSS(u) == Q) then
+   5.     Early_start(u) = max ( t(v) + l(v) - d(v,u)*II ) over all every v in PSP(u).
+   6.     start = Early_start; end = Early_start + II - 1; step = 1
+   11.  else if (PSP(u) == Q && PSS(u) != Q) then
+   12.      Late_start(u) = min ( t(v) - l(v) + d(v,u)*II ) over all every v in PSS(u).
+   13.     start = Late_start; end = Late_start - II + 1; step = -1
+   14.  else if (PSP(u) != Q && PSS(u) != Q) then
+   15.     Early_start(u) = max ( t(v) + l(v) - d(v,u)*II ) over all every v in PSP(u).
+   16.     Late_start(u) = min ( t(v) - l(v) + d(v,u)*II ) over all every v in PSS(u).
+   17.     start = Early_start;
+   18.     end = min(Early_start + II - 1 , Late_start);
+   19.     step = 1
+   20.     else "if (PSP(u) == Q && PSS(u) == Q)"
+   21.	  start = ASAP(u); end = start + II - 1; step = 1
+   22.  endif
+
+   23.  success = false
+   24.  for (c = start ; c != end ; c += step)
+   25.     if check_hardware_resources_conflicts(u, PS, c) then
+   26.       add_to_partial_schedule_at_time(u, PS, c)
+   27.       success = true
+   28.       break
+   29.     endif
+   30.  endfor
+   31.  if (success == false) then
+   32.    II = II + 1
+   33.    if (II > maxII) then
+   34.       finish - failed to schedule
+   35.	 endif
+   36.    goto 2.
+   37.  endif
+   38. endfor
+   39. if (calculate_register_pressure(PS) > maxRP) then
+   40.    goto 32.
+   41. endif
+   42. compute epilogue & prologue
+   43. finish - succeeded to schedule
+*/
+
+/* A limit on the number of cycles that resource conflicts can span.  ??? Should
+   be provided by DFA, and be dependent on the type of insn scheduled.  Currently
+   set to 0 to save compile time.  */
+#define DFA_HISTORY SMS_DFA_HISTORY
+
+/* A threshold for the number of repeated unsuccessful attempts to insert
+   an empty row, before we flush the partial schedule and start over.  */
+#define MAX_SPLIT_NUM 10
+/* Given the partial schedule PS, this function calculates and returns the
+   cycles in which we can schedule the node with the given index I.
+   NOTE: Here we do the backtracking in SMS, in some special cases. We have
+   noticed that there are several cases in which we fail    to SMS the loop
+   because the sched window of a node is empty    due to tight data-deps. In
+   such cases we want to unschedule    some of the predecessors/successors
+   until we get non-empty    scheduling window.  It returns -1 if the
+   scheduling window is empty and zero otherwise.  */
+
+static int
+get_sched_window (partial_schedule_ptr ps, int *nodes_order, int i,
+		  sbitmap sched_nodes, int ii, int *start_p, int *step_p, int *end_p)
+{
+  int start, step, end;
+  ddg_edge_ptr e;
+  int u = nodes_order [i];
+  ddg_node_ptr u_node = &ps->g->nodes[u];
+  sbitmap psp = sbitmap_alloc (ps->g->num_nodes);
+  sbitmap pss = sbitmap_alloc (ps->g->num_nodes);
+  sbitmap u_node_preds = NODE_PREDECESSORS (u_node);
+  sbitmap u_node_succs = NODE_SUCCESSORS (u_node);
+  int psp_not_empty;
+  int pss_not_empty;
+
+  /* 1. compute sched window for u (start, end, step).  */
+  sbitmap_zero (psp);
+  sbitmap_zero (pss);
+  psp_not_empty = sbitmap_a_and_b_cg (psp, u_node_preds, sched_nodes);
+  pss_not_empty = sbitmap_a_and_b_cg (pss, u_node_succs, sched_nodes);
+
+  if (psp_not_empty && !pss_not_empty)
+    {
+      int early_start = INT_MIN;
+
+      end = INT_MAX;
+      for (e = u_node->in; e != 0; e = e->next_in)
+	{
+	  ddg_node_ptr v_node = e->src;
+
+          if (dump_file)
+            {     
+	      fprintf (dump_file, "\nProcessing edge: ");
+              print_ddg_edge (dump_file, e);
+	      fprintf (dump_file,
+		       "\nScheduling %d (%d) in psp_not_empty,"
+		       " checking p %d (%d): ", u_node->cuid,
+		       INSN_UID (u_node->insn), v_node->cuid, INSN_UID
+		       (v_node->insn));
+            }
+
+	  if (TEST_BIT (sched_nodes, v_node->cuid))
+	    {
+              int p_st = SCHED_TIME (v_node);
+
+              early_start =
+                MAX (early_start, p_st + e->latency - (e->distance * ii));
+
+              if (dump_file)
+                fprintf (dump_file, 
+                         "pred st = %d; early_start = %d; latency: %d",
+                         p_st, early_start, e->latency);
+
+	      if (e->data_type == MEM_DEP)
+		end = MIN (end, SCHED_TIME (v_node) + ii - 1);
+	    }
+         else if (dump_file)
+            fprintf (dump_file, "the node is not scheduled\n");
+	}
+      start = early_start;
+      end = MIN (end, early_start + ii);
+      /* Schedule the node close to it's predecessors.  */
+      step = 1;
+
+      if (dump_file)
+        fprintf (dump_file,
+		 "\nScheduling %d (%d) in a window (%d..%d) with step %d\n",
+		 u_node->cuid, INSN_UID (u_node->insn), start, end, step);
+    }
+
+  else if (!psp_not_empty && pss_not_empty)
+    {
+      int late_start = INT_MAX;
+
+      end = INT_MIN;
+      for (e = u_node->out; e != 0; e = e->next_out)
+	{
+	  ddg_node_ptr v_node = e->dest;
+
+          if (dump_file)
+            {
+              fprintf (dump_file, "\nProcessing edge:");
+              print_ddg_edge (dump_file, e);
+              fprintf (dump_file,
+                       "\nScheduling %d (%d) in pss_not_empty,"
+                       " checking s %d (%d): ", u_node->cuid,
+                       INSN_UID (u_node->insn), v_node->cuid, INSN_UID
+                       (v_node->insn));
+            }
+
+	  if (TEST_BIT (sched_nodes, v_node->cuid))
+	    {
+              int s_st = SCHED_TIME (v_node);
+
+              late_start = MIN (late_start,
+                                s_st - e->latency + (e->distance * ii));
+
+              if (dump_file)
+                fprintf (dump_file, 
+                         "succ st = %d; late_start = %d; latency = %d",
+                         s_st, late_start, e->latency);
+
+	      if (e->data_type == MEM_DEP)
+		end = MAX (end, SCHED_TIME (v_node) - ii + 1);
+             if (dump_file)
+                 fprintf (dump_file, "end = %d\n", end);
+
+	    }
+          else if (dump_file)
+            fprintf (dump_file, "the node is not scheduled\n");
+
+	}
+      start = late_start;
+      end = MAX (end, late_start - ii);
+      /* Schedule the node close to it's successors.  */
+      step = -1;
+
+      if (dump_file)
+        fprintf (dump_file,
+                 "\nScheduling %d (%d) in a window (%d..%d) with step %d\n",
+                 u_node->cuid, INSN_UID (u_node->insn), start, end, step);
+
+    }
+
+  else if (psp_not_empty && pss_not_empty)
+    {
+      int early_start = INT_MIN;
+      int late_start = INT_MAX;
+      int count_preds = 0;
+      int count_succs = 0;
+
+      start = INT_MIN;
+      end = INT_MAX;
+      for (e = u_node->in; e != 0; e = e->next_in)
+	{
+	  ddg_node_ptr v_node = e->src;
+
+	  if (dump_file)
+	    {
+              fprintf (dump_file, "\nProcessing edge:");
+              print_ddg_edge (dump_file, e);
+	      fprintf (dump_file,
+		       "\nScheduling %d (%d) in psp_pss_not_empty,"
+		       " checking p %d (%d): ", u_node->cuid, INSN_UID
+		       (u_node->insn), v_node->cuid, INSN_UID
+		       (v_node->insn));
+	    }
+
+	  if (TEST_BIT (sched_nodes, v_node->cuid))
+	    {
+              int p_st = SCHED_TIME (v_node);
+
+	      early_start = MAX (early_start,
+				 p_st + e->latency
+				 - (e->distance * ii));
+
+              if (dump_file)
+                fprintf (dump_file, 
+                         "pred st = %d; early_start = %d; latency = %d",
+                         p_st, early_start, e->latency);
+
+              if (e->type == TRUE_DEP && e->data_type == REG_DEP)
+                count_preds++;
+
+	      if (e->data_type == MEM_DEP)
+		end = MIN (end, SCHED_TIME (v_node) + ii - 1);
+	    }
+          else if (dump_file)
+            fprintf (dump_file, "the node is not scheduled\n");
+
+	}
+      for (e = u_node->out; e != 0; e = e->next_out)
+	{
+	  ddg_node_ptr v_node = e->dest;
+
+	  if (dump_file)
+	    {
+              fprintf (dump_file, "\nProcessing edge:");
+              print_ddg_edge (dump_file, e);
+	      fprintf (dump_file,
+		       "\nScheduling %d (%d) in psp_pss_not_empty,"
+		       " checking s %d (%d): ", u_node->cuid, INSN_UID
+		       (u_node->insn), v_node->cuid, INSN_UID
+		       (v_node->insn));
+	    }
+
+	  if (TEST_BIT (sched_nodes, v_node->cuid))
+	    {
+              int s_st = SCHED_TIME (v_node);
+
+	      late_start = MIN (late_start,
+				s_st - e->latency
+				+ (e->distance * ii));
+
+              if (dump_file)
+                fprintf (dump_file, 
+                         "succ st = %d; late_start = %d; latency = %d",
+                         s_st, late_start, e->latency);
+
+               if (e->type == TRUE_DEP && e->data_type == REG_DEP)
+                 count_succs++;
+
+	      if (e->data_type == MEM_DEP)
+		start = MAX (start, SCHED_TIME (v_node) - ii + 1);
+	    }
+          else if (dump_file)
+            fprintf (dump_file, "the node is not scheduled\n");
+
+	}
+      start = MAX (start, early_start);
+      end = MIN (end, MIN (early_start + ii, late_start + 1));
+      step = 1;
+      /* If there are more successors than predecessors schedule the
+         node close to it's successors.  */
+      if (count_succs >= count_preds)
+        {
+          int old_start = start;
+
+          start = end - 1;
+          end = old_start - 1;
+          step = -1;
+        }
+    }
+  else /* psp is empty && pss is empty.  */
+    {
+      start = SCHED_ASAP (u_node);
+      end = start + ii;
+      step = 1;
+    }
+
+  *start_p = start;
+  *step_p = step;
+  *end_p = end;
+  sbitmap_free (psp);
+  sbitmap_free (pss);
+
+  if ((start >= end && step == 1) || (start <= end && step == -1))
+    {
+      if (dump_file)
+	fprintf (dump_file, "\nEmpty window: start=%d, end=%d, step=%d\n",
+		 start, end, step);
+    return -1;
+    }
+
+    return 0;
+}
+
+/* Calculate MUST_PRECEDE/MUST_FOLLOW bitmaps of U_NODE; which is the
+   node currently been scheduled.  At the end of the calculation
+   MUST_PRECEDE/MUST_FOLLOW contains all predecessors/successors of
+   U_NODE which are (1) already scheduled in the first/last row of
+   U_NODE's scheduling window, (2) whose dependence inequality with U
+   becomes an equality when U is scheduled in this same row, and (3)
+   whose dependence latency is zero.
+
+   The first and last rows are calculated using the following parameters:
+   START/END rows - The cycles that begins/ends the traversal on the window;
+   searching for an empty cycle to schedule U_NODE.
+   STEP - The direction in which we traverse the window.
+   II - The initiation interval.  */
+
+static void
+calculate_must_precede_follow (ddg_node_ptr u_node, int start, int end,
+			       int step, int ii, sbitmap sched_nodes,
+			       sbitmap must_precede, sbitmap must_follow)
+{
+  ddg_edge_ptr e;
+  int first_cycle_in_window, last_cycle_in_window;
+
+  gcc_assert (must_precede && must_follow);
+
+  /* Consider the following scheduling window:
+     {first_cycle_in_window, first_cycle_in_window+1, ...,
+     last_cycle_in_window}.  If step is 1 then the following will be
+     the order we traverse the window: {start=first_cycle_in_window,
+     first_cycle_in_window+1, ..., end=last_cycle_in_window+1},
+     or {start=last_cycle_in_window, last_cycle_in_window-1, ...,
+     end=first_cycle_in_window-1} if step is -1.  */
+  first_cycle_in_window = (step == 1) ? start : end - step;
+  last_cycle_in_window = (step == 1) ? end - step : start;
+
+  sbitmap_zero (must_precede);
+  sbitmap_zero (must_follow);
+
+  if (dump_file)
+    fprintf (dump_file, "\nmust_precede: ");
+
+  /* Instead of checking if:
+      (SMODULO (SCHED_TIME (e->src), ii) == first_row_in_window)
+      && ((SCHED_TIME (e->src) + e->latency - (e->distance * ii)) ==
+             first_cycle_in_window)
+      && e->latency == 0
+     we use the fact that latency is non-negative:
+      SCHED_TIME (e->src) - (e->distance * ii) <=
+      SCHED_TIME (e->src) + e->latency - (e->distance * ii)) <=
+      first_cycle_in_window
+     and check only if
+      SCHED_TIME (e->src) - (e->distance * ii) == first_cycle_in_window  */
+  for (e = u_node->in; e != 0; e = e->next_in)
+    if (TEST_BIT (sched_nodes, e->src->cuid)
+	&& ((SCHED_TIME (e->src) - (e->distance * ii)) ==
+             first_cycle_in_window))
+      {
+	if (dump_file)
+	  fprintf (dump_file, "%d ", e->src->cuid);
+
+	SET_BIT (must_precede, e->src->cuid);
+      }
+
+  if (dump_file)
+    fprintf (dump_file, "\nmust_follow: ");
+
+  /* Instead of checking if:
+      (SMODULO (SCHED_TIME (e->dest), ii) == last_row_in_window)
+      && ((SCHED_TIME (e->dest) - e->latency + (e->distance * ii)) ==
+             last_cycle_in_window)
+      && e->latency == 0
+     we use the fact that latency is non-negative:
+      SCHED_TIME (e->dest) + (e->distance * ii) >=
+      SCHED_TIME (e->dest) - e->latency + (e->distance * ii)) >= 
+      last_cycle_in_window
+     and check only if
+      SCHED_TIME (e->dest) + (e->distance * ii) == last_cycle_in_window  */
+  for (e = u_node->out; e != 0; e = e->next_out)
+    if (TEST_BIT (sched_nodes, e->dest->cuid)
+	&& ((SCHED_TIME (e->dest) + (e->distance * ii)) ==
+             last_cycle_in_window))
+      {
+	if (dump_file)
+	  fprintf (dump_file, "%d ", e->dest->cuid);
+
+	SET_BIT (must_follow, e->dest->cuid);
+      }
+
+  if (dump_file)
+    fprintf (dump_file, "\n");
+}
+
+/* Return 1 if U_NODE can be scheduled in CYCLE.  Use the following
+   parameters to decide if that's possible:
+   PS - The partial schedule.
+   U - The serial number of U_NODE.
+   NUM_SPLITS - The number of row splits made so far.
+   MUST_PRECEDE - The nodes that must precede U_NODE. (only valid at
+   the first row of the scheduling window)
+   MUST_FOLLOW - The nodes that must follow U_NODE. (only valid at the
+   last row of the scheduling window)  */
+
+static bool
+try_scheduling_node_in_cycle (partial_schedule_ptr ps, ddg_node_ptr u_node,
+			      int u, int cycle, sbitmap sched_nodes,
+			      int *num_splits, sbitmap must_precede,
+			      sbitmap must_follow)
+{
+  ps_insn_ptr psi;
+  bool success = 0;
+
+  verify_partial_schedule (ps, sched_nodes);
+  psi = ps_add_node_check_conflicts (ps, u_node, cycle,
+				     must_precede, must_follow);
+  if (psi)
+    {
+      SCHED_TIME (u_node) = cycle;
+      SET_BIT (sched_nodes, u);
+      success = 1;
+      *num_splits = 0;
+      if (dump_file)
+	fprintf (dump_file, "Scheduled w/o split in %d\n", cycle);
+
+    }
+
+  return success;
+}
+
+/* This function implements the scheduling algorithm for SMS according to the
+   above algorithm.  */
+static partial_schedule_ptr
+sms_schedule_by_order (ddg_ptr g, int mii, int maxii, int *nodes_order)
+{
+  int ii = mii;
+  int i, c, success, num_splits = 0;
+  int flush_and_start_over = true;
+  int num_nodes = g->num_nodes;
+  int start, end, step; /* Place together into one struct?  */
+  sbitmap sched_nodes = sbitmap_alloc (num_nodes);
+  sbitmap must_precede = sbitmap_alloc (num_nodes);
+  sbitmap must_follow = sbitmap_alloc (num_nodes);
+  sbitmap tobe_scheduled = sbitmap_alloc (num_nodes);
+
+  partial_schedule_ptr ps = create_partial_schedule (ii, g, DFA_HISTORY);
+
+  sbitmap_ones (tobe_scheduled);
+  sbitmap_zero (sched_nodes);
+
+  while (flush_and_start_over && (ii < maxii))
+    {
+
+      if (dump_file)
+	fprintf (dump_file, "Starting with ii=%d\n", ii);
+      flush_and_start_over = false;
+      sbitmap_zero (sched_nodes);
+
+      for (i = 0; i < num_nodes; i++)
+	{
+	  int u = nodes_order[i];
+  	  ddg_node_ptr u_node = &ps->g->nodes[u];
+	  rtx insn = u_node->insn;
+
+	  if (!INSN_P (insn))
+	    {
+	      RESET_BIT (tobe_scheduled, u);
+	      continue;
+	    }
+
+	  if (JUMP_P (insn)) /* Closing branch handled later.  */
+	    {
+	      RESET_BIT (tobe_scheduled, u);
+	      continue;
+	    }
+
+	  if (TEST_BIT (sched_nodes, u))
+	    continue;
+
+	  /* Try to get non-empty scheduling window.  */
+	 success = 0;
+         if (get_sched_window (ps, nodes_order, i, sched_nodes, ii, &start,
+                                &step, &end) == 0)
+            {
+              if (dump_file)
+                fprintf (dump_file, "\nTrying to schedule node %d \
+                        INSN = %d  in (%d .. %d) step %d\n", u, (INSN_UID
+                        (g->nodes[u].insn)), start, end, step);
+
+              gcc_assert ((step > 0 && start < end)
+                          || (step < 0 && start > end));
+
+              calculate_must_precede_follow (u_node, start, end, step, ii,
+                                             sched_nodes, must_precede,
+                                             must_follow);
+
+              for (c = start; c != end; c += step)
+                {
+                  sbitmap tmp_precede = NULL;
+                  sbitmap tmp_follow = NULL;
+
+                  if (c == start)
+                    {
+                      if (step == 1)
+                        tmp_precede = must_precede;
+                      else      /* step == -1.  */
+                        tmp_follow = must_follow;
+                    }
+                  if (c == end - step)
+                    {
+                      if (step == 1)
+                        tmp_follow = must_follow;
+                      else      /* step == -1.  */
+                        tmp_precede = must_precede;
+                    }
+
+                  success =
+                    try_scheduling_node_in_cycle (ps, u_node, u, c,
+                                                  sched_nodes,
+                                                  &num_splits, tmp_precede,
+                                                  tmp_follow);
+                  if (success)
+                    break;
+                }
+
+              verify_partial_schedule (ps, sched_nodes);
+            }
+            if (!success)
+            {
+              int split_row;
+
+              if (ii++ == maxii)
+                break;
+
+              if (num_splits >= MAX_SPLIT_NUM)
+                {
+                  num_splits = 0;
+                  flush_and_start_over = true;
+                  verify_partial_schedule (ps, sched_nodes);
+                  reset_partial_schedule (ps, ii);
+                  verify_partial_schedule (ps, sched_nodes);
+                  break;
+                }
+
+              num_splits++;
+              if (step == 1)
+                split_row = compute_split_row (sched_nodes, start, end,
+                                               ps->ii, u_node);
+              else
+                split_row = compute_split_row (sched_nodes, end, start,
+                                               ps->ii, u_node);
+
+              ps_insert_empty_row (ps, split_row, sched_nodes);
+              i--;              /* Go back and retry node i.  */
+
+              if (dump_file)
+                fprintf (dump_file, "num_splits=%d\n", num_splits);
+            }
+
+          /* ??? If (success), check register pressure estimates.  */
+        }                       /* Continue with next node.  */
+    }                           /* While flush_and_start_over.  */
+  if (ii >= maxii)
+    {
+      free_partial_schedule (ps);
+      ps = NULL;
+    }
+  else
+    gcc_assert (sbitmap_equal (tobe_scheduled, sched_nodes));
+
+  sbitmap_free (sched_nodes);
+  sbitmap_free (must_precede);
+  sbitmap_free (must_follow);
+  sbitmap_free (tobe_scheduled);
+
+  return ps;
+}
+
+/* This function inserts a new empty row into PS at the position
+   according to SPLITROW, keeping all already scheduled instructions
+   intact and updating their SCHED_TIME and cycle accordingly.  */
+static void
+ps_insert_empty_row (partial_schedule_ptr ps, int split_row,
+		     sbitmap sched_nodes)
+{
+  ps_insn_ptr crr_insn;
+  ps_insn_ptr *rows_new;
+  int ii = ps->ii;
+  int new_ii = ii + 1;
+  int row;
+
+  verify_partial_schedule (ps, sched_nodes);
+
+  /* We normalize sched_time and rotate ps to have only non-negative sched
+     times, for simplicity of updating cycles after inserting new row.  */
+  split_row -= ps->min_cycle;
+  split_row = SMODULO (split_row, ii);
+  if (dump_file)
+    fprintf (dump_file, "split_row=%d\n", split_row);
+
+  normalize_sched_times (ps);
+  rotate_partial_schedule (ps, ps->min_cycle);
+
+  rows_new = (ps_insn_ptr *) xcalloc (new_ii, sizeof (ps_insn_ptr));
+  for (row = 0; row < split_row; row++)
+    {
+      rows_new[row] = ps->rows[row];
+      ps->rows[row] = NULL;
+      for (crr_insn = rows_new[row];
+	   crr_insn; crr_insn = crr_insn->next_in_row)
+	{
+	  ddg_node_ptr u = crr_insn->node;
+	  int new_time = SCHED_TIME (u) + (SCHED_TIME (u) / ii);
+
+	  SCHED_TIME (u) = new_time;
+	  crr_insn->cycle = new_time;
+	  SCHED_ROW (u) = new_time % new_ii;
+	  SCHED_STAGE (u) = new_time / new_ii;
+	}
+
+    }
+
+  rows_new[split_row] = NULL;
+
+  for (row = split_row; row < ii; row++)
+    {
+      rows_new[row + 1] = ps->rows[row];
+      ps->rows[row] = NULL;
+      for (crr_insn = rows_new[row + 1];
+	   crr_insn; crr_insn = crr_insn->next_in_row)
+	{
+	  ddg_node_ptr u = crr_insn->node;
+	  int new_time = SCHED_TIME (u) + (SCHED_TIME (u) / ii) + 1;
+
+	  SCHED_TIME (u) = new_time;
+	  crr_insn->cycle = new_time;
+	  SCHED_ROW (u) = new_time % new_ii;
+	  SCHED_STAGE (u) = new_time / new_ii;
+	}
+    }
+
+  /* Updating ps.  */
+  ps->min_cycle = ps->min_cycle + ps->min_cycle / ii
+    + (SMODULO (ps->min_cycle, ii) >= split_row ? 1 : 0);
+  ps->max_cycle = ps->max_cycle + ps->max_cycle / ii
+    + (SMODULO (ps->max_cycle, ii) >= split_row ? 1 : 0);
+  free (ps->rows);
+  ps->rows = rows_new;
+  ps->ii = new_ii;
+  gcc_assert (ps->min_cycle >= 0);
+
+  verify_partial_schedule (ps, sched_nodes);
+
+  if (dump_file)
+    fprintf (dump_file, "min_cycle=%d, max_cycle=%d\n", ps->min_cycle,
+	     ps->max_cycle);
+}
+
+/* Given U_NODE which is the node that failed to be scheduled; LOW and
+   UP which are the boundaries of it's scheduling window; compute using
+   SCHED_NODES and II a row in the partial schedule that can be split
+   which will separate a critical predecessor from a critical successor
+   thereby expanding the window, and return it.  */
+static int
+compute_split_row (sbitmap sched_nodes, int low, int up, int ii,
+		   ddg_node_ptr u_node)
+{
+  ddg_edge_ptr e;
+  int lower = INT_MIN, upper = INT_MAX;
+  ddg_node_ptr crit_pred = NULL;
+  ddg_node_ptr crit_succ = NULL;
+  int crit_cycle;
+
+  for (e = u_node->in; e != 0; e = e->next_in)
+    {
+      ddg_node_ptr v_node = e->src;
+
+      if (TEST_BIT (sched_nodes, v_node->cuid)
+	  && (low == SCHED_TIME (v_node) + e->latency - (e->distance * ii)))
+	if (SCHED_TIME (v_node) > lower)
+	  {
+	    crit_pred = v_node;
+	    lower = SCHED_TIME (v_node);
+	  }
+    }
+
+  if (crit_pred != NULL)
+    {
+      crit_cycle = SCHED_TIME (crit_pred) + 1;
+      return SMODULO (crit_cycle, ii);
+    }
+
+  for (e = u_node->out; e != 0; e = e->next_out)
+    {
+      ddg_node_ptr v_node = e->dest;
+      if (TEST_BIT (sched_nodes, v_node->cuid)
+	  && (up == SCHED_TIME (v_node) - e->latency + (e->distance * ii)))
+	if (SCHED_TIME (v_node) < upper)
+	  {
+	    crit_succ = v_node;
+	    upper = SCHED_TIME (v_node);
+	  }
+    }
+
+  if (crit_succ != NULL)
+    {
+      crit_cycle = SCHED_TIME (crit_succ);
+      return SMODULO (crit_cycle, ii);
+    }
+
+  if (dump_file)
+    fprintf (dump_file, "Both crit_pred and crit_succ are NULL\n");
+
+  return SMODULO ((low + up + 1) / 2, ii);
+}
+
+static void
+verify_partial_schedule (partial_schedule_ptr ps, sbitmap sched_nodes)
+{
+  int row;
+  ps_insn_ptr crr_insn;
+
+  for (row = 0; row < ps->ii; row++)
+    for (crr_insn = ps->rows[row]; crr_insn; crr_insn = crr_insn->next_in_row)
+      {
+	ddg_node_ptr u = crr_insn->node;
+
+	gcc_assert (TEST_BIT (sched_nodes, u->cuid));
+	/* ??? Test also that all nodes of sched_nodes are in ps, perhaps by
+	   popcount (sched_nodes) == number of insns in ps.  */
+	gcc_assert (SCHED_TIME (u) >= ps->min_cycle);
+	gcc_assert (SCHED_TIME (u) <= ps->max_cycle);
+      }
+}
+
+
+/* This page implements the algorithm for ordering the nodes of a DDG
+   for modulo scheduling, activated through the
+   "int sms_order_nodes (ddg_ptr, int mii, int * result)" API.  */
+
+#define ORDER_PARAMS(x) ((struct node_order_params *) (x)->aux.info)
+#define ASAP(x) (ORDER_PARAMS ((x))->asap)
+#define ALAP(x) (ORDER_PARAMS ((x))->alap)
+#define HEIGHT(x) (ORDER_PARAMS ((x))->height)
+#define MOB(x) (ALAP ((x)) - ASAP ((x)))
+#define DEPTH(x) (ASAP ((x)))
+
+typedef struct node_order_params * nopa;
+
+static void order_nodes_of_sccs (ddg_all_sccs_ptr, int * result);
+static int order_nodes_in_scc (ddg_ptr, sbitmap, sbitmap, int*, int);
+static nopa  calculate_order_params (ddg_ptr, int, int *);
+static int find_max_asap (ddg_ptr, sbitmap);
+static int find_max_hv_min_mob (ddg_ptr, sbitmap);
+static int find_max_dv_min_mob (ddg_ptr, sbitmap);
+
+enum sms_direction {BOTTOMUP, TOPDOWN};
+
+struct node_order_params
+{
+  int asap;
+  int alap;
+  int height;
+};
+
+/* Check if NODE_ORDER contains a permutation of 0 .. NUM_NODES-1.  */
+static void
+check_nodes_order (int *node_order, int num_nodes)
+{
+  int i;
+  sbitmap tmp = sbitmap_alloc (num_nodes);
+
+  sbitmap_zero (tmp);
+
+  if (dump_file)
+    fprintf (dump_file, "SMS final nodes order: \n");
+
+  for (i = 0; i < num_nodes; i++)
+    {
+      int u = node_order[i];
+
+      if (dump_file)
+        fprintf (dump_file, "%d ", u);
+      gcc_assert (u < num_nodes && u >= 0 && !TEST_BIT (tmp, u));
+
+      SET_BIT (tmp, u);
+    }
+ 
+  if (dump_file)
+    fprintf (dump_file, "\n");
+ 
+  sbitmap_free (tmp);
+}
+
+/* Order the nodes of G for scheduling and pass the result in
+   NODE_ORDER.  Also set aux.count of each node to ASAP.
+   Put maximal ASAP to PMAX_ASAP.  Return the recMII for the given DDG.  */
+static int
+sms_order_nodes (ddg_ptr g, int mii, int * node_order, int *pmax_asap)
+{
+  int i;
+  int rec_mii = 0;
+  ddg_all_sccs_ptr sccs = create_ddg_all_sccs (g);
+
+  nopa nops = calculate_order_params (g, mii, pmax_asap);
+
+  if (dump_file)
+    print_sccs (dump_file, sccs, g);
+
+  order_nodes_of_sccs (sccs, node_order);
+
+  if (sccs->num_sccs > 0)
+    /* First SCC has the largest recurrence_length.  */
+    rec_mii = sccs->sccs[0]->recurrence_length;
+
+  /* Save ASAP before destroying node_order_params.  */
+  for (i = 0; i < g->num_nodes; i++)
+    {
+      ddg_node_ptr v = &g->nodes[i];
+      v->aux.count = ASAP (v);
+    }
+
+  free (nops);
+  free_ddg_all_sccs (sccs);
+  check_nodes_order (node_order, g->num_nodes);
+
+  return rec_mii;
+}
+
+static void
+order_nodes_of_sccs (ddg_all_sccs_ptr all_sccs, int * node_order)
+{
+  int i, pos = 0;
+  ddg_ptr g = all_sccs->ddg;
+  int num_nodes = g->num_nodes;
+  sbitmap prev_sccs = sbitmap_alloc (num_nodes);
+  sbitmap on_path = sbitmap_alloc (num_nodes);
+  sbitmap tmp = sbitmap_alloc (num_nodes);
+  sbitmap ones = sbitmap_alloc (num_nodes);
+
+  sbitmap_zero (prev_sccs);
+  sbitmap_ones (ones);
+
+  /* Perform the node ordering starting from the SCC with the highest recMII.
+     For each SCC order the nodes according to their ASAP/ALAP/HEIGHT etc.  */
+  for (i = 0; i < all_sccs->num_sccs; i++)
+    {
+      ddg_scc_ptr scc = all_sccs->sccs[i];
+
+      /* Add nodes on paths from previous SCCs to the current SCC.  */
+      find_nodes_on_paths (on_path, g, prev_sccs, scc->nodes);
+      sbitmap_a_or_b (tmp, scc->nodes, on_path);
+
+      /* Add nodes on paths from the current SCC to previous SCCs.  */
+      find_nodes_on_paths (on_path, g, scc->nodes, prev_sccs);
+      sbitmap_a_or_b (tmp, tmp, on_path);
+
+      /* Remove nodes of previous SCCs from current extended SCC.  */
+      sbitmap_difference (tmp, tmp, prev_sccs);
+
+      pos = order_nodes_in_scc (g, prev_sccs, tmp, node_order, pos);
+      /* Above call to order_nodes_in_scc updated prev_sccs |= tmp.  */
+    }
+
+  /* Handle the remaining nodes that do not belong to any scc.  Each call
+     to order_nodes_in_scc handles a single connected component.  */
+  while (pos < g->num_nodes)
+    {
+      sbitmap_difference (tmp, ones, prev_sccs);
+      pos = order_nodes_in_scc (g, prev_sccs, tmp, node_order, pos);
+    }
+  sbitmap_free (prev_sccs);
+  sbitmap_free (on_path);
+  sbitmap_free (tmp);
+  sbitmap_free (ones);
+}
+
+/* MII is needed if we consider backarcs (that do not close recursive cycles).  */
+static struct node_order_params *
+calculate_order_params (ddg_ptr g, int mii ATTRIBUTE_UNUSED, int *pmax_asap)
+{
+  int u;
+  int max_asap;
+  int num_nodes = g->num_nodes;
+  ddg_edge_ptr e;
+  /* Allocate a place to hold ordering params for each node in the DDG.  */
+  nopa node_order_params_arr;
+
+  /* Initialize of ASAP/ALAP/HEIGHT to zero.  */
+  node_order_params_arr = (nopa) xcalloc (num_nodes,
+					  sizeof (struct node_order_params));
+
+  /* Set the aux pointer of each node to point to its order_params structure.  */
+  for (u = 0; u < num_nodes; u++)
+    g->nodes[u].aux.info = &node_order_params_arr[u];
+
+  /* Disregarding a backarc from each recursive cycle to obtain a DAG,
+     calculate ASAP, ALAP, mobility, distance, and height for each node
+     in the dependence (direct acyclic) graph.  */
+
+  /* We assume that the nodes in the array are in topological order.  */
+
+  max_asap = 0;
+  for (u = 0; u < num_nodes; u++)
+    {
+      ddg_node_ptr u_node = &g->nodes[u];
+
+      ASAP (u_node) = 0;
+      for (e = u_node->in; e; e = e->next_in)
+	if (e->distance == 0)
+	  ASAP (u_node) = MAX (ASAP (u_node),
+			       ASAP (e->src) + e->latency);
+      max_asap = MAX (max_asap, ASAP (u_node));
+    }
+
+  for (u = num_nodes - 1; u > -1; u--)
+    {
+      ddg_node_ptr u_node = &g->nodes[u];
+
+      ALAP (u_node) = max_asap;
+      HEIGHT (u_node) = 0;
+      for (e = u_node->out; e; e = e->next_out)
+	if (e->distance == 0)
+	  {
+	    ALAP (u_node) = MIN (ALAP (u_node),
+				 ALAP (e->dest) - e->latency);
+	    HEIGHT (u_node) = MAX (HEIGHT (u_node),
+				   HEIGHT (e->dest) + e->latency);
+	  }
+    }
+  if (dump_file)
+  {
+    fprintf (dump_file, "\nOrder params\n");
+    for (u = 0; u < num_nodes; u++)
+      {
+        ddg_node_ptr u_node = &g->nodes[u];
+
+        fprintf (dump_file, "node %d, ASAP: %d, ALAP: %d, HEIGHT: %d\n", u,
+                 ASAP (u_node), ALAP (u_node), HEIGHT (u_node));
+      }
+  }
+
+  *pmax_asap = max_asap;
+  return node_order_params_arr;
+}
+
+static int
+find_max_asap (ddg_ptr g, sbitmap nodes)
+{
+  unsigned int u = 0;
+  int max_asap = -1;
+  int result = -1;
+  sbitmap_iterator sbi;
+
+  EXECUTE_IF_SET_IN_SBITMAP (nodes, 0, u, sbi)
+    {
+      ddg_node_ptr u_node = &g->nodes[u];
+
+      if (max_asap < ASAP (u_node))
+	{
+	  max_asap = ASAP (u_node);
+	  result = u;
+	}
+    }
+  return result;
+}
+
+static int
+find_max_hv_min_mob (ddg_ptr g, sbitmap nodes)
+{
+  unsigned int u = 0;
+  int max_hv = -1;
+  int min_mob = INT_MAX;
+  int result = -1;
+  sbitmap_iterator sbi;
+
+  EXECUTE_IF_SET_IN_SBITMAP (nodes, 0, u, sbi)
+    {
+      ddg_node_ptr u_node = &g->nodes[u];
+
+      if (max_hv < HEIGHT (u_node))
+	{
+	  max_hv = HEIGHT (u_node);
+	  min_mob = MOB (u_node);
+	  result = u;
+	}
+      else if ((max_hv == HEIGHT (u_node))
+	       && (min_mob > MOB (u_node)))
+	{
+	  min_mob = MOB (u_node);
+	  result = u;
+	}
+    }
+  return result;
+}
+
+static int
+find_max_dv_min_mob (ddg_ptr g, sbitmap nodes)
+{
+  unsigned int u = 0;
+  int max_dv = -1;
+  int min_mob = INT_MAX;
+  int result = -1;
+  sbitmap_iterator sbi;
+
+  EXECUTE_IF_SET_IN_SBITMAP (nodes, 0, u, sbi)
+    {
+      ddg_node_ptr u_node = &g->nodes[u];
+
+      if (max_dv < DEPTH (u_node))
+	{
+	  max_dv = DEPTH (u_node);
+	  min_mob = MOB (u_node);
+	  result = u;
+	}
+      else if ((max_dv == DEPTH (u_node))
+	       && (min_mob > MOB (u_node)))
+	{
+	  min_mob = MOB (u_node);
+	  result = u;
+	}
+    }
+  return result;
+}
+
+/* Places the nodes of SCC into the NODE_ORDER array starting
+   at position POS, according to the SMS ordering algorithm.
+   NODES_ORDERED (in&out parameter) holds the bitset of all nodes in
+   the NODE_ORDER array, starting from position zero.  */
+static int
+order_nodes_in_scc (ddg_ptr g, sbitmap nodes_ordered, sbitmap scc,
+		    int * node_order, int pos)
+{
+  enum sms_direction dir;
+  int num_nodes = g->num_nodes;
+  sbitmap workset = sbitmap_alloc (num_nodes);
+  sbitmap tmp = sbitmap_alloc (num_nodes);
+  sbitmap zero_bitmap = sbitmap_alloc (num_nodes);
+  sbitmap predecessors = sbitmap_alloc (num_nodes);
+  sbitmap successors = sbitmap_alloc (num_nodes);
+
+  sbitmap_zero (predecessors);
+  find_predecessors (predecessors, g, nodes_ordered);
+
+  sbitmap_zero (successors);
+  find_successors (successors, g, nodes_ordered);
+
+  sbitmap_zero (tmp);
+  if (sbitmap_a_and_b_cg (tmp, predecessors, scc))
+    {
+      sbitmap_copy (workset, tmp);
+      dir = BOTTOMUP;
+    }
+  else if (sbitmap_a_and_b_cg (tmp, successors, scc))
+    {
+      sbitmap_copy (workset, tmp);
+      dir = TOPDOWN;
+    }
+  else
+    {
+      int u;
+
+      sbitmap_zero (workset);
+      if ((u = find_max_asap (g, scc)) >= 0)
+	SET_BIT (workset, u);
+      dir = BOTTOMUP;
+    }
+
+  sbitmap_zero (zero_bitmap);
+  while (!sbitmap_equal (workset, zero_bitmap))
+    {
+      int v;
+      ddg_node_ptr v_node;
+      sbitmap v_node_preds;
+      sbitmap v_node_succs;
+
+      if (dir == TOPDOWN)
+	{
+	  while (!sbitmap_equal (workset, zero_bitmap))
+	    {
+	      v = find_max_hv_min_mob (g, workset);
+	      v_node = &g->nodes[v];
+	      node_order[pos++] = v;
+	      v_node_succs = NODE_SUCCESSORS (v_node);
+	      sbitmap_a_and_b (tmp, v_node_succs, scc);
+
+	      /* Don't consider the already ordered successors again.  */
+	      sbitmap_difference (tmp, tmp, nodes_ordered);
+	      sbitmap_a_or_b (workset, workset, tmp);
+	      RESET_BIT (workset, v);
+	      SET_BIT (nodes_ordered, v);
+	    }
+	  dir = BOTTOMUP;
+	  sbitmap_zero (predecessors);
+	  find_predecessors (predecessors, g, nodes_ordered);
+	  sbitmap_a_and_b (workset, predecessors, scc);
+	}
+      else
+	{
+	  while (!sbitmap_equal (workset, zero_bitmap))
+	    {
+	      v = find_max_dv_min_mob (g, workset);
+	      v_node = &g->nodes[v];
+	      node_order[pos++] = v;
+	      v_node_preds = NODE_PREDECESSORS (v_node);
+	      sbitmap_a_and_b (tmp, v_node_preds, scc);
+
+	      /* Don't consider the already ordered predecessors again.  */
+	      sbitmap_difference (tmp, tmp, nodes_ordered);
+	      sbitmap_a_or_b (workset, workset, tmp);
+	      RESET_BIT (workset, v);
+	      SET_BIT (nodes_ordered, v);
+	    }
+	  dir = TOPDOWN;
+	  sbitmap_zero (successors);
+	  find_successors (successors, g, nodes_ordered);
+	  sbitmap_a_and_b (workset, successors, scc);
+	}
+    }
+  sbitmap_free (tmp);
+  sbitmap_free (workset);
+  sbitmap_free (zero_bitmap);
+  sbitmap_free (predecessors);
+  sbitmap_free (successors);
+  return pos;
+}
+
+
+/* This page contains functions for manipulating partial-schedules during
+   modulo scheduling.  */
+
+/* Create a partial schedule and allocate a memory to hold II rows.  */
+
+static partial_schedule_ptr
+create_partial_schedule (int ii, ddg_ptr g, int history)
+{
+  partial_schedule_ptr ps = XNEW (struct partial_schedule);
+  ps->rows = (ps_insn_ptr *) xcalloc (ii, sizeof (ps_insn_ptr));
+  ps->ii = ii;
+  ps->history = history;
+  ps->min_cycle = INT_MAX;
+  ps->max_cycle = INT_MIN;
+  ps->g = g;
+
+  return ps;
+}
+
+/* Free the PS_INSNs in rows array of the given partial schedule.
+   ??? Consider caching the PS_INSN's.  */
+static void
+free_ps_insns (partial_schedule_ptr ps)
+{
+  int i;
+
+  for (i = 0; i < ps->ii; i++)
+    {
+      while (ps->rows[i])
+	{
+	  ps_insn_ptr ps_insn = ps->rows[i]->next_in_row;
+
+	  free (ps->rows[i]);
+	  ps->rows[i] = ps_insn;
+	}
+      ps->rows[i] = NULL;
+    }
+}
+
+/* Free all the memory allocated to the partial schedule.  */
+
+static void
+free_partial_schedule (partial_schedule_ptr ps)
+{
+  if (!ps)
+    return;
+  free_ps_insns (ps);
+  free (ps->rows);
+  free (ps);
+}
+
+/* Clear the rows array with its PS_INSNs, and create a new one with
+   NEW_II rows.  */
+
+static void
+reset_partial_schedule (partial_schedule_ptr ps, int new_ii)
+{
+  if (!ps)
+    return;
+  free_ps_insns (ps);
+  if (new_ii == ps->ii)
+    return;
+  ps->rows = (ps_insn_ptr *) xrealloc (ps->rows, new_ii
+						 * sizeof (ps_insn_ptr));
+  memset (ps->rows, 0, new_ii * sizeof (ps_insn_ptr));
+  ps->ii = new_ii;
+  ps->min_cycle = INT_MAX;
+  ps->max_cycle = INT_MIN;
+}
+
+/* Prints the partial schedule as an ii rows array, for each rows
+   print the ids of the insns in it.  */
+void
+print_partial_schedule (partial_schedule_ptr ps, FILE *dump)
+{
+  int i;
+
+  for (i = 0; i < ps->ii; i++)
+    {
+      ps_insn_ptr ps_i = ps->rows[i];
+
+      fprintf (dump, "\n[ROW %d ]: ", i);
+      while (ps_i)
+	{
+	  fprintf (dump, "%d, ",
+		   INSN_UID (ps_i->node->insn));
+	  ps_i = ps_i->next_in_row;
+	}
+    }
+}
+
+/* Creates an object of PS_INSN and initializes it to the given parameters.  */
+static ps_insn_ptr
+create_ps_insn (ddg_node_ptr node, int rest_count, int cycle)
+{
+  ps_insn_ptr ps_i = XNEW (struct ps_insn);
+
+  ps_i->node = node;
+  ps_i->next_in_row = NULL;
+  ps_i->prev_in_row = NULL;
+  ps_i->row_rest_count = rest_count;
+  ps_i->cycle = cycle;
+
+  return ps_i;
+}
+
+
+/* Removes the given PS_INSN from the partial schedule.  Returns false if the
+   node is not found in the partial schedule, else returns true.  */
+static bool
+remove_node_from_ps (partial_schedule_ptr ps, ps_insn_ptr ps_i)
+{
+  int row;
+
+  if (!ps || !ps_i)
+    return false;
+
+  row = SMODULO (ps_i->cycle, ps->ii);
+  if (! ps_i->prev_in_row)
+    {
+      if (ps_i != ps->rows[row])
+	return false;
+
+      ps->rows[row] = ps_i->next_in_row;
+      if (ps->rows[row])
+	ps->rows[row]->prev_in_row = NULL;
+    }
+  else
+    {
+      ps_i->prev_in_row->next_in_row = ps_i->next_in_row;
+      if (ps_i->next_in_row)
+	ps_i->next_in_row->prev_in_row = ps_i->prev_in_row;
+    }
+  free (ps_i);
+  return true;
+}
+
+/* Unlike what literature describes for modulo scheduling (which focuses
+   on VLIW machines) the order of the instructions inside a cycle is
+   important.  Given the bitmaps MUST_FOLLOW and MUST_PRECEDE we know
+   where the current instruction should go relative to the already
+   scheduled instructions in the given cycle.  Go over these
+   instructions and find the first possible column to put it in.  */
+static bool
+ps_insn_find_column (partial_schedule_ptr ps, ps_insn_ptr ps_i,
+		     sbitmap must_precede, sbitmap must_follow)
+{
+  ps_insn_ptr next_ps_i;
+  ps_insn_ptr first_must_follow = NULL;
+  ps_insn_ptr last_must_precede = NULL;
+  int row;
+
+  if (! ps_i)
+    return false;
+
+  row = SMODULO (ps_i->cycle, ps->ii);
+
+  /* Find the first must follow and the last must precede
+     and insert the node immediately after the must precede
+     but make sure that it there is no must follow after it.  */
+  for (next_ps_i = ps->rows[row];
+       next_ps_i;
+       next_ps_i = next_ps_i->next_in_row)
+    {
+      if (must_follow && TEST_BIT (must_follow, next_ps_i->node->cuid)
+	  && ! first_must_follow)
+        first_must_follow = next_ps_i;
+      if (must_precede && TEST_BIT (must_precede, next_ps_i->node->cuid))
+        {
+          /* If we have already met a node that must follow, then
+	     there is no possible column.  */
+  	  if (first_must_follow)
+            return false;
+	  else
+            last_must_precede = next_ps_i;
+        }
+    }
+
+  /* Now insert the node after INSERT_AFTER_PSI.  */
+
+  if (! last_must_precede)
+    {
+      ps_i->next_in_row = ps->rows[row];
+      ps_i->prev_in_row = NULL;
+      if (ps_i->next_in_row)
+    	ps_i->next_in_row->prev_in_row = ps_i;
+      ps->rows[row] = ps_i;
+    }
+  else
+    {
+      ps_i->next_in_row = last_must_precede->next_in_row;
+      last_must_precede->next_in_row = ps_i;
+      ps_i->prev_in_row = last_must_precede;
+      if (ps_i->next_in_row)
+        ps_i->next_in_row->prev_in_row = ps_i;
+    }
+
+  return true;
+}
+
+/* Advances the PS_INSN one column in its current row; returns false
+   in failure and true in success.  Bit N is set in MUST_FOLLOW if 
+   the node with cuid N must be come after the node pointed to by 
+   PS_I when scheduled in the same cycle.  */
+static int
+ps_insn_advance_column (partial_schedule_ptr ps, ps_insn_ptr ps_i,
+			sbitmap must_follow)
+{
+  ps_insn_ptr prev, next;
+  int row;
+  ddg_node_ptr next_node;
+
+  if (!ps || !ps_i)
+    return false;
+
+  row = SMODULO (ps_i->cycle, ps->ii);
+
+  if (! ps_i->next_in_row)
+    return false;
+
+  next_node = ps_i->next_in_row->node;
+
+  /* Check if next_in_row is dependent on ps_i, both having same sched
+     times (typically ANTI_DEP).  If so, ps_i cannot skip over it.  */
+  if (must_follow && TEST_BIT (must_follow, next_node->cuid))
+    return false;
+
+  /* Advance PS_I over its next_in_row in the doubly linked list.  */
+  prev = ps_i->prev_in_row;
+  next = ps_i->next_in_row;
+
+  if (ps_i == ps->rows[row])
+    ps->rows[row] = next;
+
+  ps_i->next_in_row = next->next_in_row;
+
+  if (next->next_in_row)
+    next->next_in_row->prev_in_row = ps_i;
+
+  next->next_in_row = ps_i;
+  ps_i->prev_in_row = next;
+
+  next->prev_in_row = prev;
+  if (prev)
+    prev->next_in_row = next;
+
+  return true;
+}
+
+/* Inserts a DDG_NODE to the given partial schedule at the given cycle.
+   Returns 0 if this is not possible and a PS_INSN otherwise.  Bit N is 
+   set in MUST_PRECEDE/MUST_FOLLOW if the node with cuid N must be come 
+   before/after (respectively) the node pointed to by PS_I when scheduled 
+   in the same cycle.  */
+static ps_insn_ptr
+add_node_to_ps (partial_schedule_ptr ps, ddg_node_ptr node, int cycle,
+		sbitmap must_precede, sbitmap must_follow)
+{
+  ps_insn_ptr ps_i;
+  int rest_count = 1;
+  int row = SMODULO (cycle, ps->ii);
+
+  if (ps->rows[row]
+      && ps->rows[row]->row_rest_count >= issue_rate)
+    return NULL;
+
+  if (ps->rows[row])
+    rest_count += ps->rows[row]->row_rest_count;
+
+  ps_i = create_ps_insn (node, rest_count, cycle);
+
+  /* Finds and inserts PS_I according to MUST_FOLLOW and
+     MUST_PRECEDE.  */
+  if (! ps_insn_find_column (ps, ps_i, must_precede, must_follow))
+    {
+      free (ps_i);
+      return NULL;
+    }
+
+  return ps_i;
+}
+
+/* Advance time one cycle.  Assumes DFA is being used.  */
+static void
+advance_one_cycle (void)
+{
+  if (targetm.sched.dfa_pre_cycle_insn)
+    state_transition (curr_state,
+		      targetm.sched.dfa_pre_cycle_insn ());
+
+  state_transition (curr_state, NULL);
+
+  if (targetm.sched.dfa_post_cycle_insn)
+    state_transition (curr_state,
+		      targetm.sched.dfa_post_cycle_insn ());
+}
+
+
+
+/* Checks if PS has resource conflicts according to DFA, starting from
+   FROM cycle to TO cycle; returns true if there are conflicts and false
+   if there are no conflicts.  Assumes DFA is being used.  */
+static int
+ps_has_conflicts (partial_schedule_ptr ps, int from, int to)
+{
+  int cycle;
+
+  state_reset (curr_state);
+
+  for (cycle = from; cycle <= to; cycle++)
+    {
+      ps_insn_ptr crr_insn;
+      /* Holds the remaining issue slots in the current row.  */
+      int can_issue_more = issue_rate;
+
+      /* Walk through the DFA for the current row.  */
+      for (crr_insn = ps->rows[SMODULO (cycle, ps->ii)];
+	   crr_insn;
+	   crr_insn = crr_insn->next_in_row)
+	{
+	  rtx insn = crr_insn->node->insn;
+
+	  if (!INSN_P (insn))
+	    continue;
+
+	  /* Check if there is room for the current insn.  */
+	  if (!can_issue_more || state_dead_lock_p (curr_state))
+	    return true;
+
+	  /* Update the DFA state and return with failure if the DFA found
+	     resource conflicts.  */
+	  if (state_transition (curr_state, insn) >= 0)
+	    return true;
+
+	  if (targetm.sched.variable_issue)
+	    can_issue_more =
+	      targetm.sched.variable_issue (sched_dump, sched_verbose,
+					    insn, can_issue_more);
+	  /* A naked CLOBBER or USE generates no instruction, so don't
+	     let them consume issue slots.  */
+	  else if (GET_CODE (PATTERN (insn)) != USE
+		   && GET_CODE (PATTERN (insn)) != CLOBBER)
+	    can_issue_more--;
+	}
+
+      /* Advance the DFA to the next cycle.  */
+      advance_one_cycle ();
+    }
+  return false;
+}
+
+/* Checks if the given node causes resource conflicts when added to PS at
+   cycle C.  If not the node is added to PS and returned; otherwise zero
+   is returned.  Bit N is set in MUST_PRECEDE/MUST_FOLLOW if the node with 
+   cuid N must be come before/after (respectively) the node pointed to by 
+   PS_I when scheduled in the same cycle.  */
+ps_insn_ptr
+ps_add_node_check_conflicts (partial_schedule_ptr ps, ddg_node_ptr n,
+   			     int c, sbitmap must_precede,
+			     sbitmap must_follow)
+{
+  int has_conflicts = 0;
+  ps_insn_ptr ps_i;
+
+  /* First add the node to the PS, if this succeeds check for
+     conflicts, trying different issue slots in the same row.  */
+  if (! (ps_i = add_node_to_ps (ps, n, c, must_precede, must_follow)))
+    return NULL; /* Failed to insert the node at the given cycle.  */
+
+  has_conflicts = ps_has_conflicts (ps, c, c)
+		  || (ps->history > 0
+		      && ps_has_conflicts (ps,
+					   c - ps->history,
+					   c + ps->history));
+
+  /* Try different issue slots to find one that the given node can be
+     scheduled in without conflicts.  */
+  while (has_conflicts)
+    {
+      if (! ps_insn_advance_column (ps, ps_i, must_follow))
+	break;
+      has_conflicts = ps_has_conflicts (ps, c, c)
+		      || (ps->history > 0
+			  && ps_has_conflicts (ps,
+					       c - ps->history,
+					       c + ps->history));
+    }
+
+  if (has_conflicts)
+    {
+      remove_node_from_ps (ps, ps_i);
+      return NULL;
+    }
+
+  ps->min_cycle = MIN (ps->min_cycle, c);
+  ps->max_cycle = MAX (ps->max_cycle, c);
+  return ps_i;
+}
+
+/* Rotate the rows of PS such that insns scheduled at time
+   START_CYCLE will appear in row 0.  Updates max/min_cycles.  */
+void
+rotate_partial_schedule (partial_schedule_ptr ps, int start_cycle)
+{
+  int i, row, backward_rotates;
+  int last_row = ps->ii - 1;
+
+  if (start_cycle == 0)
+    return;
+
+  backward_rotates = SMODULO (start_cycle, ps->ii);
+
+  /* Revisit later and optimize this into a single loop.  */
+  for (i = 0; i < backward_rotates; i++)
+    {
+      ps_insn_ptr first_row = ps->rows[0];
+
+      for (row = 0; row < last_row; row++)
+	ps->rows[row] = ps->rows[row+1];
+
+      ps->rows[last_row] = first_row;
+    }
+
+  ps->max_cycle -= start_cycle;
+  ps->min_cycle -= start_cycle;
+}
+
+#endif /* INSN_SCHEDULING */
+
+static bool
+gate_handle_sms (void)
+{
+  return (optimize > 0 && flag_modulo_sched);
+}
+
+
+/* Run instruction scheduler.  */
+/* Perform SMS module scheduling.  */
+static unsigned int
+rest_of_handle_sms (void)
+{
+#ifdef INSN_SCHEDULING
+  basic_block bb;
+
+  /* Collect loop information to be used in SMS.  */
+  cfg_layout_initialize (0);
+  sms_schedule ();
+
+  /* Update the life information, because we add pseudos.  */
+  max_regno = max_reg_num ();
+
+  /* Finalize layout changes.  */
+  FOR_EACH_BB (bb)
+    if (bb->next_bb != EXIT_BLOCK_PTR)
+      bb->aux = bb->next_bb;
+  free_dominance_info (CDI_DOMINATORS);
+  cfg_layout_finalize ();
+#endif /* INSN_SCHEDULING */
+  return 0;
+}
+
+struct rtl_opt_pass pass_sms =
+{
+ {
+  RTL_PASS,
+  "sms",                                /* name */
+  gate_handle_sms,                      /* gate */
+  rest_of_handle_sms,                   /* execute */
+  NULL,                                 /* sub */
+  NULL,                                 /* next */
+  0,                                    /* static_pass_number */
+  TV_SMS,                               /* tv_id */
+  0,                                    /* properties_required */
+  0,                                    /* properties_provided */
+  0,                                    /* properties_destroyed */
+  TODO_dump_func,                       /* todo_flags_start */
+  TODO_df_finish | TODO_verify_rtl_sharing |
+  TODO_dump_func |
+  TODO_ggc_collect                      /* todo_flags_finish */
+ }
+};
+