Initial checkin of GCC 4.9.0 from trunk (r208799).

Change-Id: I48a3c08bb98542aa215912a75f03c0890e497dba

1 files changed, 1620 insertions, 0 deletions

diff --git a/gcc-4.9/gcc/graphite-scop-detection.c b/gcc-4.9/gcc/graphite-scop-detection.c
new file mode 100644
index 000000000..1d7c7485f
--- /dev/null
+++ b/gcc-4.9/gcc/graphite-scop-detection.c
@@ -0,0 +1,1620 @@
+/* Detection of Static Control Parts (SCoP) for Graphite.
+   Copyright (C) 2009-2014 Free Software Foundation, Inc.
+   Contributed by Sebastian Pop <sebastian.pop@amd.com> and
+   Tobias Grosser <grosser@fim.uni-passau.de>.
+
+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"
+
+#ifdef HAVE_cloog
+#include <isl/set.h>
+#include <isl/map.h>
+#include <isl/union_map.h>
+#include <cloog/cloog.h>
+#include <cloog/isl/domain.h>
+#endif
+
+#include "system.h"
+#include "coretypes.h"
+#include "tree.h"
+#include "basic-block.h"
+#include "tree-ssa-alias.h"
+#include "internal-fn.h"
+#include "gimple-expr.h"
+#include "is-a.h"
+#include "gimple.h"
+#include "gimple-iterator.h"
+#include "gimple-ssa.h"
+#include "tree-phinodes.h"
+#include "ssa-iterators.h"
+#include "tree-ssa-loop-manip.h"
+#include "tree-ssa-loop-niter.h"
+#include "tree-ssa-loop.h"
+#include "tree-into-ssa.h"
+#include "tree-ssa.h"
+#include "cfgloop.h"
+#include "tree-chrec.h"
+#include "tree-data-ref.h"
+#include "tree-scalar-evolution.h"
+#include "tree-pass.h"
+#include "sese.h"
+#include "tree-ssa-propagate.h"
+
+#ifdef HAVE_cloog
+#include "graphite-poly.h"
+#include "graphite-scop-detection.h"
+
+/* Forward declarations.  */
+static void make_close_phi_nodes_unique (basic_block);
+
+/* The type of the analyzed basic block.  */
+
+typedef enum gbb_type {
+  GBB_UNKNOWN,
+  GBB_LOOP_SING_EXIT_HEADER,
+  GBB_LOOP_MULT_EXIT_HEADER,
+  GBB_LOOP_EXIT,
+  GBB_COND_HEADER,
+  GBB_SIMPLE,
+  GBB_LAST
+} gbb_type;
+
+/* Detect the type of BB.  Loop headers are only marked, if they are
+   new.  This means their loop_father is different to LAST_LOOP.
+   Otherwise they are treated like any other bb and their type can be
+   any other type.  */
+
+static gbb_type
+get_bb_type (basic_block bb, struct loop *last_loop)
+{
+  vec<basic_block> dom;
+  int nb_dom;
+  struct loop *loop = bb->loop_father;
+
+  /* Check, if we entry into a new loop. */
+  if (loop != last_loop)
+    {
+      if (single_exit (loop) != NULL)
+        return GBB_LOOP_SING_EXIT_HEADER;
+      else if (loop->num != 0)
+        return GBB_LOOP_MULT_EXIT_HEADER;
+      else
+	return GBB_COND_HEADER;
+    }
+
+  dom = get_dominated_by (CDI_DOMINATORS, bb);
+  nb_dom = dom.length ();
+  dom.release ();
+
+  if (nb_dom == 0)
+    return GBB_LAST;
+
+  if (nb_dom == 1 && single_succ_p (bb))
+    return GBB_SIMPLE;
+
+  return GBB_COND_HEADER;
+}
+
+/* A SCoP detection region, defined using bbs as borders.
+
+   All control flow touching this region, comes in passing basic_block
+   ENTRY and leaves passing basic_block EXIT.  By using bbs instead of
+   edges for the borders we are able to represent also regions that do
+   not have a single entry or exit edge.
+
+   But as they have a single entry basic_block and a single exit
+   basic_block, we are able to generate for every sd_region a single
+   entry and exit edge.
+
+   1   2
+    \ /
+     3	<- entry
+     |
+     4
+    / \			This region contains: {3, 4, 5, 6, 7, 8}
+   5   6
+   |   |
+   7   8
+    \ /
+     9	<- exit  */
+
+
+typedef struct sd_region_p
+{
+  /* The entry bb dominates all bbs in the sd_region.  It is part of
+     the region.  */
+  basic_block entry;
+
+  /* The exit bb postdominates all bbs in the sd_region, but is not
+     part of the region.  */
+  basic_block exit;
+} sd_region;
+
+
+
+/* Moves the scops from SOURCE to TARGET and clean up SOURCE.  */
+
+static void
+move_sd_regions (vec<sd_region> *source, vec<sd_region> *target)
+{
+  sd_region *s;
+  int i;
+
+  FOR_EACH_VEC_ELT (*source, i, s)
+    target->safe_push (*s);
+
+  source->release ();
+}
+
+/* Something like "n * m" is not allowed.  */
+
+static bool
+graphite_can_represent_init (tree e)
+{
+  switch (TREE_CODE (e))
+    {
+    case POLYNOMIAL_CHREC:
+      return graphite_can_represent_init (CHREC_LEFT (e))
+	&& graphite_can_represent_init (CHREC_RIGHT (e));
+
+    case MULT_EXPR:
+      if (chrec_contains_symbols (TREE_OPERAND (e, 0)))
+	return graphite_can_represent_init (TREE_OPERAND (e, 0))
+	  && tree_fits_shwi_p (TREE_OPERAND (e, 1));
+      else
+	return graphite_can_represent_init (TREE_OPERAND (e, 1))
+	  && tree_fits_shwi_p (TREE_OPERAND (e, 0));
+
+    case PLUS_EXPR:
+    case POINTER_PLUS_EXPR:
+    case MINUS_EXPR:
+      return graphite_can_represent_init (TREE_OPERAND (e, 0))
+	&& graphite_can_represent_init (TREE_OPERAND (e, 1));
+
+    case NEGATE_EXPR:
+    case BIT_NOT_EXPR:
+    CASE_CONVERT:
+    case NON_LVALUE_EXPR:
+      return graphite_can_represent_init (TREE_OPERAND (e, 0));
+
+   default:
+     break;
+    }
+
+  return true;
+}
+
+/* Return true when SCEV can be represented in the polyhedral model.
+
+   An expression can be represented, if it can be expressed as an
+   affine expression.  For loops (i, j) and parameters (m, n) all
+   affine expressions are of the form:
+
+   x1 * i + x2 * j + x3 * m + x4 * n + x5 * 1 where x1..x5 element of Z
+
+   1 i + 20 j + (-2) m + 25
+
+   Something like "i * n" or "n * m" is not allowed.  */
+
+static bool
+graphite_can_represent_scev (tree scev)
+{
+  if (chrec_contains_undetermined (scev))
+    return false;
+
+  switch (TREE_CODE (scev))
+    {
+    case PLUS_EXPR:
+    case MINUS_EXPR:
+      return graphite_can_represent_scev (TREE_OPERAND (scev, 0))
+	&& graphite_can_represent_scev (TREE_OPERAND (scev, 1));
+
+    case MULT_EXPR:
+      return !CONVERT_EXPR_CODE_P (TREE_CODE (TREE_OPERAND (scev, 0)))
+	&& !CONVERT_EXPR_CODE_P (TREE_CODE (TREE_OPERAND (scev, 1)))
+	&& !(chrec_contains_symbols (TREE_OPERAND (scev, 0))
+	     && chrec_contains_symbols (TREE_OPERAND (scev, 1)))
+	&& graphite_can_represent_init (scev)
+	&& graphite_can_represent_scev (TREE_OPERAND (scev, 0))
+	&& graphite_can_represent_scev (TREE_OPERAND (scev, 1));
+
+    case POLYNOMIAL_CHREC:
+      /* Check for constant strides.  With a non constant stride of
+	 'n' we would have a value of 'iv * n'.  Also check that the
+	 initial value can represented: for example 'n * m' cannot be
+	 represented.  */
+      if (!evolution_function_right_is_integer_cst (scev)
+	  || !graphite_can_represent_init (scev))
+	return false;
+
+    default:
+      break;
+    }
+
+  /* Only affine functions can be represented.  */
+  if (!scev_is_linear_expression (scev))
+    return false;
+
+  return true;
+}
+
+
+/* Return true when EXPR can be represented in the polyhedral model.
+
+   This means an expression can be represented, if it is linear with
+   respect to the loops and the strides are non parametric.
+   LOOP is the place where the expr will be evaluated.  SCOP_ENTRY defines the
+   entry of the region we analyse.  */
+
+static bool
+graphite_can_represent_expr (basic_block scop_entry, loop_p loop,
+			     tree expr)
+{
+  tree scev = analyze_scalar_evolution (loop, expr);
+
+  scev = instantiate_scev (scop_entry, loop, scev);
+
+  return graphite_can_represent_scev (scev);
+}
+
+/* Return true if the data references of STMT can be represented by
+   Graphite.  */
+
+static bool
+stmt_has_simple_data_refs_p (loop_p outermost_loop ATTRIBUTE_UNUSED,
+			     gimple stmt)
+{
+  data_reference_p dr;
+  unsigned i;
+  int j;
+  bool res = true;
+  vec<data_reference_p> drs = vNULL;
+  loop_p outer;
+
+  for (outer = loop_containing_stmt (stmt); outer; outer = loop_outer (outer))
+    {
+      graphite_find_data_references_in_stmt (outer,
+					     loop_containing_stmt (stmt),
+					     stmt, &drs);
+
+      FOR_EACH_VEC_ELT (drs, j, dr)
+	for (i = 0; i < DR_NUM_DIMENSIONS (dr); i++)
+	  if (!graphite_can_represent_scev (DR_ACCESS_FN (dr, i)))
+	    {
+	      res = false;
+	      goto done;
+	    }
+
+      free_data_refs (drs);
+      drs.create (0);
+    }
+
+ done:
+  free_data_refs (drs);
+  return res;
+}
+
+/* Return true only when STMT is simple enough for being handled by
+   Graphite.  This depends on SCOP_ENTRY, as the parameters are
+   initialized relatively to this basic block, the linear functions
+   are initialized to OUTERMOST_LOOP and BB is the place where we try
+   to evaluate the STMT.  */
+
+static bool
+stmt_simple_for_scop_p (basic_block scop_entry, loop_p outermost_loop,
+			gimple stmt, basic_block bb)
+{
+  loop_p loop = bb->loop_father;
+
+  gcc_assert (scop_entry);
+
+  /* GIMPLE_ASM and GIMPLE_CALL may embed arbitrary side effects.
+     Calls have side-effects, except those to const or pure
+     functions.  */
+  if (gimple_has_volatile_ops (stmt)
+      || (gimple_code (stmt) == GIMPLE_CALL
+	  && !(gimple_call_flags (stmt) & (ECF_CONST | ECF_PURE)))
+      || (gimple_code (stmt) == GIMPLE_ASM))
+    return false;
+
+  if (is_gimple_debug (stmt))
+    return true;
+
+  if (!stmt_has_simple_data_refs_p (outermost_loop, stmt))
+    return false;
+
+  switch (gimple_code (stmt))
+    {
+    case GIMPLE_RETURN:
+    case GIMPLE_LABEL:
+      return true;
+
+    case GIMPLE_COND:
+      {
+	tree op;
+	ssa_op_iter op_iter;
+        enum tree_code code = gimple_cond_code (stmt);
+
+	/* We can handle all binary comparisons.  Inequalities are
+	   also supported as they can be represented with union of
+	   polyhedra.  */
+        if (!(code == LT_EXPR
+	      || code == GT_EXPR
+	      || code == LE_EXPR
+	      || code == GE_EXPR
+	      || code == EQ_EXPR
+	      || code == NE_EXPR))
+          return false;
+
+	FOR_EACH_SSA_TREE_OPERAND (op, stmt, op_iter, SSA_OP_ALL_USES)
+	  if (!graphite_can_represent_expr (scop_entry, loop, op)
+	      /* We can not handle REAL_TYPE. Failed for pr39260.  */
+	      || TREE_CODE (TREE_TYPE (op)) == REAL_TYPE)
+	    return false;
+
+	return true;
+      }
+
+    case GIMPLE_ASSIGN:
+    case GIMPLE_CALL:
+      return true;
+
+    default:
+      /* These nodes cut a new scope.  */
+      return false;
+    }
+
+  return false;
+}
+
+/* Returns the statement of BB that contains a harmful operation: that
+   can be a function call with side effects, the induction variables
+   are not linear with respect to SCOP_ENTRY, etc.  The current open
+   scop should end before this statement.  The evaluation is limited using
+   OUTERMOST_LOOP as outermost loop that may change.  */
+
+static gimple
+harmful_stmt_in_bb (basic_block scop_entry, loop_p outer_loop, basic_block bb)
+{
+  gimple_stmt_iterator gsi;
+
+  for (gsi = gsi_start_bb (bb); !gsi_end_p (gsi); gsi_next (&gsi))
+    if (!stmt_simple_for_scop_p (scop_entry, outer_loop, gsi_stmt (gsi), bb))
+      return gsi_stmt (gsi);
+
+  return NULL;
+}
+
+/* Return true if LOOP can be represented in the polyhedral
+   representation.  This is evaluated taking SCOP_ENTRY and
+   OUTERMOST_LOOP in mind.  */
+
+static bool
+graphite_can_represent_loop (basic_block scop_entry, loop_p loop)
+{
+  tree niter;
+  struct tree_niter_desc niter_desc;
+
+  /* FIXME: For the moment, graphite cannot be used on loops that
+     iterate using induction variables that wrap.  */
+
+  return number_of_iterations_exit (loop, single_exit (loop), &niter_desc, false)
+    && niter_desc.control.no_overflow
+    && (niter = number_of_latch_executions (loop))
+    && !chrec_contains_undetermined (niter)
+    && graphite_can_represent_expr (scop_entry, loop, niter);
+}
+
+/* Store information needed by scopdet_* functions.  */
+
+struct scopdet_info
+{
+  /* Exit of the open scop would stop if the current BB is harmful.  */
+  basic_block exit;
+
+  /* Where the next scop would start if the current BB is harmful.  */
+  basic_block next;
+
+  /* The bb or one of its children contains open loop exits.  That means
+     loop exit nodes that are not surrounded by a loop dominated by bb.  */
+  bool exits;
+
+  /* The bb or one of its children contains only structures we can handle.  */
+  bool difficult;
+};
+
+static struct scopdet_info build_scops_1 (basic_block, loop_p,
+					  vec<sd_region> *, loop_p);
+
+/* Calculates BB infos. If bb is difficult we add valid SCoPs dominated by BB
+   to SCOPS.  TYPE is the gbb_type of BB.  */
+
+static struct scopdet_info
+scopdet_basic_block_info (basic_block bb, loop_p outermost_loop,
+			  vec<sd_region> *scops, gbb_type type)
+{
+  loop_p loop = bb->loop_father;
+  struct scopdet_info result;
+  gimple stmt;
+
+  /* XXX: ENTRY_BLOCK_PTR could be optimized in later steps.  */
+  basic_block entry_block = ENTRY_BLOCK_PTR_FOR_FN (cfun);
+  stmt = harmful_stmt_in_bb (entry_block, outermost_loop, bb);
+  result.difficult = (stmt != NULL);
+  result.exit = NULL;
+
+  switch (type)
+    {
+    case GBB_LAST:
+      result.next = NULL;
+      result.exits = false;
+
+      /* Mark bbs terminating a SESE region difficult, if they start
+	 a condition.  */
+      if (!single_succ_p (bb))
+	result.difficult = true;
+      else
+	result.exit = single_succ (bb);
+
+      break;
+
+    case GBB_SIMPLE:
+      result.next = single_succ (bb);
+      result.exits = false;
+      result.exit = single_succ (bb);
+      break;
+
+    case GBB_LOOP_SING_EXIT_HEADER:
+      {
+	auto_vec<sd_region, 3> regions;
+	struct scopdet_info sinfo;
+	edge exit_e = single_exit (loop);
+
+	sinfo = build_scops_1 (bb, outermost_loop, &regions, loop);
+
+	if (!graphite_can_represent_loop (entry_block, loop))
+	  result.difficult = true;
+
+	result.difficult |= sinfo.difficult;
+
+	/* Try again with another loop level.  */
+	if (result.difficult
+	    && loop_depth (outermost_loop) + 1 == loop_depth (loop))
+	  {
+	    outermost_loop = loop;
+
+	    regions.release ();
+	    regions.create (3);
+
+	    sinfo = scopdet_basic_block_info (bb, outermost_loop, scops, type);
+
+	    result = sinfo;
+	    result.difficult = true;
+
+	    if (sinfo.difficult)
+	      move_sd_regions (&regions, scops);
+	    else
+	      {
+		sd_region open_scop;
+		open_scop.entry = bb;
+		open_scop.exit = exit_e->dest;
+		scops->safe_push (open_scop);
+		regions.release ();
+	      }
+	  }
+	else
+	  {
+	    result.exit = exit_e->dest;
+	    result.next = exit_e->dest;
+
+	    /* If we do not dominate result.next, remove it.  It's either
+	       the exit block, or another bb dominates it and will
+	       call the scop detection for this bb.  */
+	    if (!dominated_by_p (CDI_DOMINATORS, result.next, bb))
+	      result.next = NULL;
+
+	    if (exit_e->src->loop_father != loop)
+	      result.next = NULL;
+
+	    result.exits = false;
+
+	    if (result.difficult)
+	      move_sd_regions (&regions, scops);
+	    else
+	      regions.release ();
+	  }
+
+	break;
+      }
+
+    case GBB_LOOP_MULT_EXIT_HEADER:
+      {
+        /* XXX: For now we just do not join loops with multiple exits.  If the
+           exits lead to the same bb it may be possible to join the loop.  */
+        auto_vec<sd_region, 3> regions;
+        vec<edge> exits = get_loop_exit_edges (loop);
+        edge e;
+        int i;
+	build_scops_1 (bb, loop, &regions, loop);
+
+	/* Scan the code dominated by this loop.  This means all bbs, that are
+	   are dominated by a bb in this loop, but are not part of this loop.
+
+	   The easiest case:
+	     - The loop exit destination is dominated by the exit sources.
+
+	   TODO: We miss here the more complex cases:
+		  - The exit destinations are dominated by another bb inside
+		    the loop.
+		  - The loop dominates bbs, that are not exit destinations.  */
+        FOR_EACH_VEC_ELT (exits, i, e)
+          if (e->src->loop_father == loop
+	      && dominated_by_p (CDI_DOMINATORS, e->dest, e->src))
+	    {
+	      if (loop_outer (outermost_loop))
+		outermost_loop = loop_outer (outermost_loop);
+
+	      /* Pass loop_outer to recognize e->dest as loop header in
+		 build_scops_1.  */
+	      if (e->dest->loop_father->header == e->dest)
+		build_scops_1 (e->dest, outermost_loop, &regions,
+			       loop_outer (e->dest->loop_father));
+	      else
+		build_scops_1 (e->dest, outermost_loop, &regions,
+			       e->dest->loop_father);
+	    }
+
+        result.next = NULL;
+        result.exit = NULL;
+        result.difficult = true;
+        result.exits = false;
+        move_sd_regions (&regions, scops);
+        exits.release ();
+        break;
+      }
+    case GBB_COND_HEADER:
+      {
+	auto_vec<sd_region, 3> regions;
+	struct scopdet_info sinfo;
+	vec<basic_block> dominated;
+	int i;
+	basic_block dom_bb;
+	basic_block last_exit = NULL;
+	edge e;
+	result.exits = false;
+
+	/* First check the successors of BB, and check if it is
+	   possible to join the different branches.  */
+	FOR_EACH_VEC_SAFE_ELT (bb->succs, i, e)
+	  {
+	    /* Ignore loop exits.  They will be handled after the loop
+	       body.  */
+	    if (loop_exits_to_bb_p (loop, e->dest))
+	      {
+		result.exits = true;
+		continue;
+	      }
+
+	    /* Do not follow edges that lead to the end of the
+	       conditions block.  For example, in
+
+               |   0
+	       |  /|\
+	       | 1 2 |
+	       | | | |
+	       | 3 4 |
+	       |  \|/
+               |   6
+
+	       the edge from 0 => 6.  Only check if all paths lead to
+	       the same node 6.  */
+
+	    if (!single_pred_p (e->dest))
+	      {
+		/* Check, if edge leads directly to the end of this
+		   condition.  */
+		if (!last_exit)
+		  last_exit = e->dest;
+
+		if (e->dest != last_exit)
+		  result.difficult = true;
+
+		continue;
+	      }
+
+	    if (!dominated_by_p (CDI_DOMINATORS, e->dest, bb))
+	      {
+		result.difficult = true;
+		continue;
+	      }
+
+	    sinfo = build_scops_1 (e->dest, outermost_loop, &regions, loop);
+
+	    result.exits |= sinfo.exits;
+	    result.difficult |= sinfo.difficult;
+
+	    /* Checks, if all branches end at the same point.
+	       If that is true, the condition stays joinable.
+	       Have a look at the example above.  */
+	    if (sinfo.exit)
+	      {
+		if (!last_exit)
+		  last_exit = sinfo.exit;
+
+		if (sinfo.exit != last_exit)
+		  result.difficult = true;
+	      }
+	    else
+	      result.difficult = true;
+	  }
+
+	if (!last_exit)
+	  result.difficult = true;
+
+	/* Join the branches of the condition if possible.  */
+	if (!result.exits && !result.difficult)
+	  {
+	    /* Only return a next pointer if we dominate this pointer.
+	       Otherwise it will be handled by the bb dominating it.  */
+	    if (dominated_by_p (CDI_DOMINATORS, last_exit, bb)
+		&& last_exit != bb)
+	      result.next = last_exit;
+	    else
+	      result.next = NULL;
+
+	    result.exit = last_exit;
+
+	    regions.release ();
+	    break;
+	  }
+
+	/* Scan remaining bbs dominated by BB.  */
+	dominated = get_dominated_by (CDI_DOMINATORS, bb);
+
+	FOR_EACH_VEC_ELT (dominated, i, dom_bb)
+	  {
+	    /* Ignore loop exits: they will be handled after the loop body.  */
+	    if (loop_depth (find_common_loop (loop, dom_bb->loop_father))
+		< loop_depth (loop))
+	      {
+		result.exits = true;
+		continue;
+	      }
+
+	    /* Ignore the bbs processed above.  */
+	    if (single_pred_p (dom_bb) && single_pred (dom_bb) == bb)
+	      continue;
+
+	    if (loop_depth (loop) > loop_depth (dom_bb->loop_father))
+	      sinfo = build_scops_1 (dom_bb, outermost_loop, &regions,
+				     loop_outer (loop));
+	    else
+	      sinfo = build_scops_1 (dom_bb, outermost_loop, &regions, loop);
+
+	    result.exits |= sinfo.exits;
+	    result.difficult = true;
+	    result.exit = NULL;
+	  }
+
+	dominated.release ();
+
+	result.next = NULL;
+	move_sd_regions (&regions, scops);
+
+	break;
+      }
+
+    default:
+      gcc_unreachable ();
+    }
+
+  return result;
+}
+
+/* Starting from CURRENT we walk the dominance tree and add new sd_regions to
+   SCOPS. The analyse if a sd_region can be handled is based on the value
+   of OUTERMOST_LOOP. Only loops inside OUTERMOST loops may change.  LOOP
+   is the loop in which CURRENT is handled.
+
+   TODO: These functions got a little bit big. They definitely should be cleaned
+	 up.  */
+
+static struct scopdet_info
+build_scops_1 (basic_block current, loop_p outermost_loop,
+	       vec<sd_region> *scops, loop_p loop)
+{
+  bool in_scop = false;
+  sd_region open_scop;
+  struct scopdet_info sinfo;
+
+  /* Initialize result.  */
+  struct scopdet_info result;
+  result.exits = false;
+  result.difficult = false;
+  result.next = NULL;
+  result.exit = NULL;
+  open_scop.entry = NULL;
+  open_scop.exit = NULL;
+  sinfo.exit = NULL;
+
+  /* Loop over the dominance tree.  If we meet a difficult bb, close
+     the current SCoP.  Loop and condition header start a new layer,
+     and can only be added if all bbs in deeper layers are simple.  */
+  while (current != NULL)
+    {
+      sinfo = scopdet_basic_block_info (current, outermost_loop, scops,
+					get_bb_type (current, loop));
+
+      if (!in_scop && !(sinfo.exits || sinfo.difficult))
+        {
+	  open_scop.entry = current;
+	  open_scop.exit = NULL;
+          in_scop = true;
+        }
+      else if (in_scop && (sinfo.exits || sinfo.difficult))
+        {
+	  open_scop.exit = current;
+          scops->safe_push (open_scop);
+          in_scop = false;
+        }
+
+      result.difficult |= sinfo.difficult;
+      result.exits |= sinfo.exits;
+
+      current = sinfo.next;
+    }
+
+  /* Try to close open_scop, if we are still in an open SCoP.  */
+  if (in_scop)
+    {
+      open_scop.exit = sinfo.exit;
+      gcc_assert (open_scop.exit);
+      scops->safe_push (open_scop);
+    }
+
+  result.exit = sinfo.exit;
+  return result;
+}
+
+/* Checks if a bb is contained in REGION.  */
+
+static bool
+bb_in_sd_region (basic_block bb, sd_region *region)
+{
+  return bb_in_region (bb, region->entry, region->exit);
+}
+
+/* Returns the single entry edge of REGION, if it does not exits NULL.  */
+
+static edge
+find_single_entry_edge (sd_region *region)
+{
+  edge e;
+  edge_iterator ei;
+  edge entry = NULL;
+
+  FOR_EACH_EDGE (e, ei, region->entry->preds)
+    if (!bb_in_sd_region (e->src, region))
+      {
+	if (entry)
+	  {
+	    entry = NULL;
+	    break;
+	  }
+
+	else
+	  entry = e;
+      }
+
+  return entry;
+}
+
+/* Returns the single exit edge of REGION, if it does not exits NULL.  */
+
+static edge
+find_single_exit_edge (sd_region *region)
+{
+  edge e;
+  edge_iterator ei;
+  edge exit = NULL;
+
+  FOR_EACH_EDGE (e, ei, region->exit->preds)
+    if (bb_in_sd_region (e->src, region))
+      {
+	if (exit)
+	  {
+	    exit = NULL;
+	    break;
+	  }
+
+	else
+	  exit = e;
+      }
+
+  return exit;
+}
+
+/* Create a single entry edge for REGION.  */
+
+static void
+create_single_entry_edge (sd_region *region)
+{
+  if (find_single_entry_edge (region))
+    return;
+
+  /* There are multiple predecessors for bb_3
+
+  |  1  2
+  |  | /
+  |  |/
+  |  3	<- entry
+  |  |\
+  |  | |
+  |  4 ^
+  |  | |
+  |  |/
+  |  5
+
+  There are two edges (1->3, 2->3), that point from outside into the region,
+  and another one (5->3), a loop latch, lead to bb_3.
+
+  We split bb_3.
+
+  |  1  2
+  |  | /
+  |  |/
+  |3.0
+  |  |\     (3.0 -> 3.1) = single entry edge
+  |3.1 |  	<- entry
+  |  | |
+  |  | |
+  |  4 ^
+  |  | |
+  |  |/
+  |  5
+
+  If the loop is part of the SCoP, we have to redirect the loop latches.
+
+  |  1  2
+  |  | /
+  |  |/
+  |3.0
+  |  |      (3.0 -> 3.1) = entry edge
+  |3.1  	<- entry
+  |  |\
+  |  | |
+  |  4 ^
+  |  | |
+  |  |/
+  |  5  */
+
+  if (region->entry->loop_father->header != region->entry
+      || dominated_by_p (CDI_DOMINATORS,
+			 loop_latch_edge (region->entry->loop_father)->src,
+			 region->exit))
+    {
+      edge forwarder = split_block_after_labels (region->entry);
+      region->entry = forwarder->dest;
+    }
+  else
+    /* This case is never executed, as the loop headers seem always to have a
+       single edge pointing from outside into the loop.  */
+    gcc_unreachable ();
+
+  gcc_checking_assert (find_single_entry_edge (region));
+}
+
+/* Check if the sd_region, mentioned in EDGE, has no exit bb.  */
+
+static bool
+sd_region_without_exit (edge e)
+{
+  sd_region *r = (sd_region *) e->aux;
+
+  if (r)
+    return r->exit == NULL;
+  else
+    return false;
+}
+
+/* Create a single exit edge for REGION.  */
+
+static void
+create_single_exit_edge (sd_region *region)
+{
+  edge e;
+  edge_iterator ei;
+  edge forwarder = NULL;
+  basic_block exit;
+
+  /* We create a forwarder bb (5) for all edges leaving this region
+     (3->5, 4->5).  All other edges leading to the same bb, are moved
+     to a new bb (6).  If these edges where part of another region (2->5)
+     we update the region->exit pointer, of this region.
+
+     To identify which edge belongs to which region we depend on the e->aux
+     pointer in every edge.  It points to the region of the edge or to NULL,
+     if the edge is not part of any region.
+
+     1 2 3 4   	1->5 no region, 		2->5 region->exit = 5,
+      \| |/    	3->5 region->exit = NULL, 	4->5 region->exit = NULL
+        5	<- exit
+
+     changes to
+
+     1 2 3 4   	1->6 no region, 			2->6 region->exit = 6,
+     | | \/	3->5 no region,				4->5 no region,
+     | |  5
+      \| /	5->6 region->exit = 6
+	6
+
+     Now there is only a single exit edge (5->6).  */
+  exit = region->exit;
+  region->exit = NULL;
+  forwarder = make_forwarder_block (exit, &sd_region_without_exit, NULL);
+
+  /* Unmark the edges, that are no longer exit edges.  */
+  FOR_EACH_EDGE (e, ei, forwarder->src->preds)
+    if (e->aux)
+      e->aux = NULL;
+
+  /* Mark the new exit edge.  */
+  single_succ_edge (forwarder->src)->aux = region;
+
+  /* Update the exit bb of all regions, where exit edges lead to
+     forwarder->dest.  */
+  FOR_EACH_EDGE (e, ei, forwarder->dest->preds)
+    if (e->aux)
+      ((sd_region *) e->aux)->exit = forwarder->dest;
+
+  gcc_checking_assert (find_single_exit_edge (region));
+}
+
+/* Unmark the exit edges of all REGIONS.
+   See comment in "create_single_exit_edge". */
+
+static void
+unmark_exit_edges (vec<sd_region> regions)
+{
+  int i;
+  sd_region *s;
+  edge e;
+  edge_iterator ei;
+
+  FOR_EACH_VEC_ELT (regions, i, s)
+    FOR_EACH_EDGE (e, ei, s->exit->preds)
+      e->aux = NULL;
+}
+
+
+/* Mark the exit edges of all REGIONS.
+   See comment in "create_single_exit_edge". */
+
+static void
+mark_exit_edges (vec<sd_region> regions)
+{
+  int i;
+  sd_region *s;
+  edge e;
+  edge_iterator ei;
+
+  FOR_EACH_VEC_ELT (regions, i, s)
+    FOR_EACH_EDGE (e, ei, s->exit->preds)
+      if (bb_in_sd_region (e->src, s))
+	e->aux = s;
+}
+
+/* Create for all scop regions a single entry and a single exit edge.  */
+
+static void
+create_sese_edges (vec<sd_region> regions)
+{
+  int i;
+  sd_region *s;
+
+  FOR_EACH_VEC_ELT (regions, i, s)
+    create_single_entry_edge (s);
+
+  mark_exit_edges (regions);
+
+  FOR_EACH_VEC_ELT (regions, i, s)
+    /* Don't handle multiple edges exiting the function.  */
+    if (!find_single_exit_edge (s)
+	&& s->exit != EXIT_BLOCK_PTR_FOR_FN (cfun))
+      create_single_exit_edge (s);
+
+  unmark_exit_edges (regions);
+
+  calculate_dominance_info (CDI_DOMINATORS);
+  fix_loop_structure (NULL);
+
+#ifdef ENABLE_CHECKING
+  verify_loop_structure ();
+  verify_ssa (false);
+#endif
+}
+
+/* Create graphite SCoPs from an array of scop detection REGIONS.  */
+
+static void
+build_graphite_scops (vec<sd_region> regions,
+		      vec<scop_p> *scops)
+{
+  int i;
+  sd_region *s;
+
+  FOR_EACH_VEC_ELT (regions, i, s)
+    {
+      edge entry = find_single_entry_edge (s);
+      edge exit = find_single_exit_edge (s);
+      scop_p scop;
+
+      if (!exit)
+	continue;
+
+      scop = new_scop (new_sese (entry, exit));
+      scops->safe_push (scop);
+
+      /* Are there overlapping SCoPs?  */
+#ifdef ENABLE_CHECKING
+	{
+	  int j;
+	  sd_region *s2;
+
+	  FOR_EACH_VEC_ELT (regions, j, s2)
+	    if (s != s2)
+	      gcc_assert (!bb_in_sd_region (s->entry, s2));
+	}
+#endif
+    }
+}
+
+/* Returns true when BB contains only close phi nodes.  */
+
+static bool
+contains_only_close_phi_nodes (basic_block bb)
+{
+  gimple_stmt_iterator gsi;
+
+  for (gsi = gsi_start_bb (bb); !gsi_end_p (gsi); gsi_next (&gsi))
+    if (gimple_code (gsi_stmt (gsi)) != GIMPLE_LABEL)
+      return false;
+
+  return true;
+}
+
+/* Print statistics for SCOP to FILE.  */
+
+static void
+print_graphite_scop_statistics (FILE* file, scop_p scop)
+{
+  long n_bbs = 0;
+  long n_loops = 0;
+  long n_stmts = 0;
+  long n_conditions = 0;
+  long n_p_bbs = 0;
+  long n_p_loops = 0;
+  long n_p_stmts = 0;
+  long n_p_conditions = 0;
+
+  basic_block bb;
+
+  FOR_ALL_BB_FN (bb, cfun)
+    {
+      gimple_stmt_iterator psi;
+      loop_p loop = bb->loop_father;
+
+      if (!bb_in_sese_p (bb, SCOP_REGION (scop)))
+	continue;
+
+      n_bbs++;
+      n_p_bbs += bb->count;
+
+      if (EDGE_COUNT (bb->succs) > 1)
+	{
+	  n_conditions++;
+	  n_p_conditions += bb->count;
+	}
+
+      for (psi = gsi_start_bb (bb); !gsi_end_p (psi); gsi_next (&psi))
+	{
+	  n_stmts++;
+	  n_p_stmts += bb->count;
+	}
+
+      if (loop->header == bb && loop_in_sese_p (loop, SCOP_REGION (scop)))
+	{
+	  n_loops++;
+	  n_p_loops += bb->count;
+	}
+
+    }
+
+  fprintf (file, "\nBefore limit_scops SCoP statistics (");
+  fprintf (file, "BBS:%ld, ", n_bbs);
+  fprintf (file, "LOOPS:%ld, ", n_loops);
+  fprintf (file, "CONDITIONS:%ld, ", n_conditions);
+  fprintf (file, "STMTS:%ld)\n", n_stmts);
+  fprintf (file, "\nBefore limit_scops SCoP profiling statistics (");
+  fprintf (file, "BBS:%ld, ", n_p_bbs);
+  fprintf (file, "LOOPS:%ld, ", n_p_loops);
+  fprintf (file, "CONDITIONS:%ld, ", n_p_conditions);
+  fprintf (file, "STMTS:%ld)\n", n_p_stmts);
+}
+
+/* Print statistics for SCOPS to FILE.  */
+
+static void
+print_graphite_statistics (FILE* file, vec<scop_p> scops)
+{
+  int i;
+  scop_p scop;
+
+  FOR_EACH_VEC_ELT (scops, i, scop)
+    print_graphite_scop_statistics (file, scop);
+}
+
+/* We limit all SCoPs to SCoPs, that are completely surrounded by a loop.
+
+   Example:
+
+   for (i      |
+     {         |
+       for (j  |  SCoP 1
+       for (k  |
+     }         |
+
+   * SCoP frontier, as this line is not surrounded by any loop. *
+
+   for (l      |  SCoP 2
+
+   This is necessary as scalar evolution and parameter detection need a
+   outermost loop to initialize parameters correctly.
+
+   TODO: FIX scalar evolution and parameter detection to allow more flexible
+         SCoP frontiers.  */
+
+static void
+limit_scops (vec<scop_p> *scops)
+{
+  auto_vec<sd_region, 3> regions;
+
+  int i;
+  scop_p scop;
+
+  FOR_EACH_VEC_ELT (*scops, i, scop)
+    {
+      int j;
+      loop_p loop;
+      sese region = SCOP_REGION (scop);
+      build_sese_loop_nests (region);
+
+      FOR_EACH_VEC_ELT (SESE_LOOP_NEST (region), j, loop)
+        if (!loop_in_sese_p (loop_outer (loop), region)
+	    && single_exit (loop))
+          {
+	    sd_region open_scop;
+	    open_scop.entry = loop->header;
+	    open_scop.exit = single_exit (loop)->dest;
+
+	    /* This is a hack on top of the limit_scops hack.  The
+	       limit_scops hack should disappear all together.  */
+	    if (single_succ_p (open_scop.exit)
+		&& contains_only_close_phi_nodes (open_scop.exit))
+	      open_scop.exit = single_succ_edge (open_scop.exit)->dest;
+
+	    regions.safe_push (open_scop);
+	  }
+    }
+
+  free_scops (*scops);
+  scops->create (3);
+
+  create_sese_edges (regions);
+  build_graphite_scops (regions, scops);
+}
+
+/* Returns true when P1 and P2 are close phis with the same
+   argument.  */
+
+static inline bool
+same_close_phi_node (gimple p1, gimple p2)
+{
+  return operand_equal_p (gimple_phi_arg_def (p1, 0),
+			  gimple_phi_arg_def (p2, 0), 0);
+}
+
+/* Remove the close phi node at GSI and replace its rhs with the rhs
+   of PHI.  */
+
+static void
+remove_duplicate_close_phi (gimple phi, gimple_stmt_iterator *gsi)
+{
+  gimple use_stmt;
+  use_operand_p use_p;
+  imm_use_iterator imm_iter;
+  tree res = gimple_phi_result (phi);
+  tree def = gimple_phi_result (gsi_stmt (*gsi));
+
+  gcc_assert (same_close_phi_node (phi, gsi_stmt (*gsi)));
+
+  FOR_EACH_IMM_USE_STMT (use_stmt, imm_iter, def)
+    {
+      FOR_EACH_IMM_USE_ON_STMT (use_p, imm_iter)
+	SET_USE (use_p, res);
+
+      update_stmt (use_stmt);
+      
+      /* It is possible that we just created a duplicate close-phi
+	 for an already-processed containing loop.  Check for this
+	 case and clean it up.  */
+      if (gimple_code (use_stmt) == GIMPLE_PHI
+	  && gimple_phi_num_args (use_stmt) == 1)
+	make_close_phi_nodes_unique (gimple_bb (use_stmt));
+    }
+
+  remove_phi_node (gsi, true);
+}
+
+/* Removes all the close phi duplicates from BB.  */
+
+static void
+make_close_phi_nodes_unique (basic_block bb)
+{
+  gimple_stmt_iterator psi;
+
+  for (psi = gsi_start_phis (bb); !gsi_end_p (psi); gsi_next (&psi))
+    {
+      gimple_stmt_iterator gsi = psi;
+      gimple phi = gsi_stmt (psi);
+
+      /* At this point, PHI should be a close phi in normal form.  */
+      gcc_assert (gimple_phi_num_args (phi) == 1);
+
+      /* Iterate over the next phis and remove duplicates.  */
+      gsi_next (&gsi);
+      while (!gsi_end_p (gsi))
+	if (same_close_phi_node (phi, gsi_stmt (gsi)))
+	  remove_duplicate_close_phi (phi, &gsi);
+	else
+	  gsi_next (&gsi);
+    }
+}
+
+/* Transforms LOOP to the canonical loop closed SSA form.  */
+
+static void
+canonicalize_loop_closed_ssa (loop_p loop)
+{
+  edge e = single_exit (loop);
+  basic_block bb;
+
+  if (!e || e->flags & EDGE_ABNORMAL)
+    return;
+
+  bb = e->dest;
+
+  if (single_pred_p (bb))
+    {
+      e = split_block_after_labels (bb);
+      make_close_phi_nodes_unique (e->src);
+    }
+  else
+    {
+      gimple_stmt_iterator psi;
+      basic_block close = split_edge (e);
+
+      e = single_succ_edge (close);
+
+      for (psi = gsi_start_phis (bb); !gsi_end_p (psi); gsi_next (&psi))
+	{
+	  gimple phi = gsi_stmt (psi);
+	  unsigned i;
+
+	  for (i = 0; i < gimple_phi_num_args (phi); i++)
+	    if (gimple_phi_arg_edge (phi, i) == e)
+	      {
+		tree res, arg = gimple_phi_arg_def (phi, i);
+		use_operand_p use_p;
+		gimple close_phi;
+
+		if (TREE_CODE (arg) != SSA_NAME)
+		  continue;
+
+		close_phi = create_phi_node (NULL_TREE, close);
+		res = create_new_def_for (arg, close_phi,
+					  gimple_phi_result_ptr (close_phi));
+		add_phi_arg (close_phi, arg,
+			     gimple_phi_arg_edge (close_phi, 0),
+			     UNKNOWN_LOCATION);
+		use_p = gimple_phi_arg_imm_use_ptr (phi, i);
+		replace_exp (use_p, res);
+		update_stmt (phi);
+	      }
+	}
+
+      make_close_phi_nodes_unique (close);
+    }
+
+  /* The code above does not properly handle changes in the post dominance
+     information (yet).  */
+  free_dominance_info (CDI_POST_DOMINATORS);
+}
+
+/* Converts the current loop closed SSA form to a canonical form
+   expected by the Graphite code generation.
+
+   The loop closed SSA form has the following invariant: a variable
+   defined in a loop that is used outside the loop appears only in the
+   phi nodes in the destination of the loop exit.  These phi nodes are
+   called close phi nodes.
+
+   The canonical loop closed SSA form contains the extra invariants:
+
+   - when the loop contains only one exit, the close phi nodes contain
+   only one argument.  That implies that the basic block that contains
+   the close phi nodes has only one predecessor, that is a basic block
+   in the loop.
+
+   - the basic block containing the close phi nodes does not contain
+   other statements.
+
+   - there exist only one phi node per definition in the loop.
+*/
+
+static void
+canonicalize_loop_closed_ssa_form (void)
+{
+  loop_p loop;
+
+#ifdef ENABLE_CHECKING
+  verify_loop_closed_ssa (true);
+#endif
+
+  FOR_EACH_LOOP (loop, 0)
+    canonicalize_loop_closed_ssa (loop);
+
+  rewrite_into_loop_closed_ssa (NULL, TODO_update_ssa);
+  update_ssa (TODO_update_ssa);
+
+#ifdef ENABLE_CHECKING
+  verify_loop_closed_ssa (true);
+#endif
+}
+
+/* Find Static Control Parts (SCoP) in the current function and pushes
+   them to SCOPS.  */
+
+void
+build_scops (vec<scop_p> *scops)
+{
+  struct loop *loop = current_loops->tree_root;
+  auto_vec<sd_region, 3> regions;
+
+  canonicalize_loop_closed_ssa_form ();
+  build_scops_1 (single_succ (ENTRY_BLOCK_PTR_FOR_FN (cfun)),
+		 ENTRY_BLOCK_PTR_FOR_FN (cfun)->loop_father,
+		 &regions, loop);
+  create_sese_edges (regions);
+  build_graphite_scops (regions, scops);
+
+  if (dump_file && (dump_flags & TDF_DETAILS))
+    print_graphite_statistics (dump_file, *scops);
+
+  limit_scops (scops);
+  regions.release ();
+
+  if (dump_file && (dump_flags & TDF_DETAILS))
+    fprintf (dump_file, "\nnumber of SCoPs: %d\n",
+	     scops ? scops->length () : 0);
+}
+
+/* Pretty print to FILE all the SCoPs in DOT format and mark them with
+   different colors.  If there are not enough colors, paint the
+   remaining SCoPs in gray.
+
+   Special nodes:
+   - "*" after the node number denotes the entry of a SCoP,
+   - "#" after the node number denotes the exit of a SCoP,
+   - "()" around the node number denotes the entry or the
+     exit nodes of the SCOP.  These are not part of SCoP.  */
+
+static void
+dot_all_scops_1 (FILE *file, vec<scop_p> scops)
+{
+  basic_block bb;
+  edge e;
+  edge_iterator ei;
+  scop_p scop;
+  const char* color;
+  int i;
+
+  /* Disable debugging while printing graph.  */
+  int tmp_dump_flags = dump_flags;
+  dump_flags = 0;
+
+  fprintf (file, "digraph all {\n");
+
+  FOR_ALL_BB_FN (bb, cfun)
+    {
+      int part_of_scop = false;
+
+      /* Use HTML for every bb label.  So we are able to print bbs
+         which are part of two different SCoPs, with two different
+         background colors.  */
+      fprintf (file, "%d [label=<\n  <TABLE BORDER=\"0\" CELLBORDER=\"1\" ",
+                     bb->index);
+      fprintf (file, "CELLSPACING=\"0\">\n");
+
+      /* Select color for SCoP.  */
+      FOR_EACH_VEC_ELT (scops, i, scop)
+	{
+	  sese region = SCOP_REGION (scop);
+	  if (bb_in_sese_p (bb, region)
+	      || (SESE_EXIT_BB (region) == bb)
+	      || (SESE_ENTRY_BB (region) == bb))
+	    {
+	      switch (i % 17)
+		{
+		case 0: /* red */
+		  color = "#e41a1c";
+		  break;
+		case 1: /* blue */
+		  color = "#377eb8";
+		  break;
+		case 2: /* green */
+		  color = "#4daf4a";
+		  break;
+		case 3: /* purple */
+		  color = "#984ea3";
+		  break;
+		case 4: /* orange */
+		  color = "#ff7f00";
+		  break;
+		case 5: /* yellow */
+		  color = "#ffff33";
+		  break;
+		case 6: /* brown */
+		  color = "#a65628";
+		  break;
+		case 7: /* rose */
+		  color = "#f781bf";
+		  break;
+		case 8:
+		  color = "#8dd3c7";
+		  break;
+		case 9:
+		  color = "#ffffb3";
+		  break;
+		case 10:
+		  color = "#bebada";
+		  break;
+		case 11:
+		  color = "#fb8072";
+		  break;
+		case 12:
+		  color = "#80b1d3";
+		  break;
+		case 13:
+		  color = "#fdb462";
+		  break;
+		case 14:
+		  color = "#b3de69";
+		  break;
+		case 15:
+		  color = "#fccde5";
+		  break;
+		case 16:
+		  color = "#bc80bd";
+		  break;
+		default: /* gray */
+		  color = "#999999";
+		}
+
+	      fprintf (file, "    <TR><TD WIDTH=\"50\" BGCOLOR=\"%s\">", color);
+
+	      if (!bb_in_sese_p (bb, region))
+		fprintf (file, " (");
+
+	      if (bb == SESE_ENTRY_BB (region)
+		  && bb == SESE_EXIT_BB (region))
+		fprintf (file, " %d*# ", bb->index);
+	      else if (bb == SESE_ENTRY_BB (region))
+		fprintf (file, " %d* ", bb->index);
+	      else if (bb == SESE_EXIT_BB (region))
+		fprintf (file, " %d# ", bb->index);
+	      else
+		fprintf (file, " %d ", bb->index);
+
+	      if (!bb_in_sese_p (bb,region))
+		fprintf (file, ")");
+
+	      fprintf (file, "</TD></TR>\n");
+	      part_of_scop  = true;
+	    }
+	}
+
+      if (!part_of_scop)
+	{
+	  fprintf (file, "    <TR><TD WIDTH=\"50\" BGCOLOR=\"#ffffff\">");
+	  fprintf (file, " %d </TD></TR>\n", bb->index);
+	}
+      fprintf (file, "  </TABLE>>, shape=box, style=\"setlinewidth(0)\"]\n");
+    }
+
+  FOR_ALL_BB_FN (bb, cfun)
+    {
+      FOR_EACH_EDGE (e, ei, bb->succs)
+	      fprintf (file, "%d -> %d;\n", bb->index, e->dest->index);
+    }
+
+  fputs ("}\n\n", file);
+
+  /* Enable debugging again.  */
+  dump_flags = tmp_dump_flags;
+}
+
+/* Display all SCoPs using dotty.  */
+
+DEBUG_FUNCTION void
+dot_all_scops (vec<scop_p> scops)
+{
+  /* When debugging, enable the following code.  This cannot be used
+     in production compilers because it calls "system".  */
+#if 0
+  int x;
+  FILE *stream = fopen ("/tmp/allscops.dot", "w");
+  gcc_assert (stream);
+
+  dot_all_scops_1 (stream, scops);
+  fclose (stream);
+
+  x = system ("dotty /tmp/allscops.dot &");
+#else
+  dot_all_scops_1 (stderr, scops);
+#endif
+}
+
+/* Display all SCoPs using dotty.  */
+
+DEBUG_FUNCTION void
+dot_scop (scop_p scop)
+{
+  auto_vec<scop_p, 1> scops;
+
+  if (scop)
+    scops.safe_push (scop);
+
+  /* When debugging, enable the following code.  This cannot be used
+     in production compilers because it calls "system".  */
+#if 0
+  {
+    int x;
+    FILE *stream = fopen ("/tmp/allscops.dot", "w");
+    gcc_assert (stream);
+
+    dot_all_scops_1 (stream, scops);
+    fclose (stream);
+    x = system ("dotty /tmp/allscops.dot &");
+  }
+#else
+  dot_all_scops_1 (stderr, scops);
+#endif
+}
+
+#endif