Initial checkin of GCC 4.9.0 from trunk (r208799).

Change-Id: I48a3c08bb98542aa215912a75f03c0890e497dba

1 files changed, 4585 insertions, 0 deletions

diff --git a/gcc-4.9/gcc/df-scan.c b/gcc-4.9/gcc/df-scan.c
new file mode 100644
index 000000000..0b5b4374b
--- /dev/null
+++ b/gcc-4.9/gcc/df-scan.c
@@ -0,0 +1,4585 @@
+/* Scanning of rtl for dataflow analysis.
+   Copyright (C) 1999-2014 Free Software Foundation, Inc.
+   Originally contributed by Michael P. Hayes
+             (m.hayes@elec.canterbury.ac.nz, mhayes@redhat.com)
+   Major rewrite contributed by Danny Berlin (dberlin@dberlin.org)
+             and Kenneth Zadeck (zadeck@naturalbridge.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 "rtl.h"
+#include "tm_p.h"
+#include "insn-config.h"
+#include "recog.h"
+#include "function.h"
+#include "regs.h"
+#include "alloc-pool.h"
+#include "flags.h"
+#include "hard-reg-set.h"
+#include "basic-block.h"
+#include "sbitmap.h"
+#include "bitmap.h"
+#include "dumpfile.h"
+#include "tree.h"
+#include "target.h"
+#include "target-def.h"
+#include "df.h"
+#include "emit-rtl.h"  /* FIXME: Can go away once crtl is moved to rtl.h.  */
+
+
+typedef struct df_mw_hardreg *df_mw_hardreg_ptr;
+
+
+#ifndef HAVE_epilogue
+#define HAVE_epilogue 0
+#endif
+#ifndef HAVE_prologue
+#define HAVE_prologue 0
+#endif
+#ifndef HAVE_sibcall_epilogue
+#define HAVE_sibcall_epilogue 0
+#endif
+
+#ifndef EPILOGUE_USES
+#define EPILOGUE_USES(REGNO)  0
+#endif
+
+/* The following two macros free the vecs that hold either the refs or
+   the mw refs.  They are a little tricky because the vec has 0
+   elements is special and is not to be freed.  */
+#define df_scan_free_ref_vec(V) \
+  do { \
+    if (V && *V) \
+      free (V);  \
+  } while (0)
+
+#define df_scan_free_mws_vec(V) \
+  do { \
+    if (V && *V) \
+      free (V);  \
+  } while (0)
+
+/* The set of hard registers in eliminables[i].from. */
+
+static HARD_REG_SET elim_reg_set;
+
+/* Initialize ur_in and ur_out as if all hard registers were partially
+   available.  */
+
+struct df_collection_rec
+{
+  auto_vec<df_ref, 128> def_vec;
+  auto_vec<df_ref, 32> use_vec;
+  auto_vec<df_ref, 32> eq_use_vec;
+  auto_vec<df_mw_hardreg_ptr, 32> mw_vec;
+};
+
+static df_ref df_null_ref_rec[1];
+static struct df_mw_hardreg * df_null_mw_rec[1];
+
+static void df_ref_record (enum df_ref_class, struct df_collection_rec *,
+			   rtx, rtx *,
+			   basic_block, struct df_insn_info *,
+			   enum df_ref_type, int ref_flags);
+static void df_def_record_1 (struct df_collection_rec *, rtx *,
+			     basic_block, struct df_insn_info *,
+			     int ref_flags);
+static void df_defs_record (struct df_collection_rec *, rtx,
+			    basic_block, struct df_insn_info *,
+			    int ref_flags);
+static void df_uses_record (struct df_collection_rec *,
+			    rtx *, enum df_ref_type,
+			    basic_block, struct df_insn_info *,
+			    int ref_flags);
+
+static void df_install_ref_incremental (df_ref);
+static df_ref df_ref_create_structure (enum df_ref_class,
+				       struct df_collection_rec *, rtx, rtx *,
+				       basic_block, struct df_insn_info *,
+				       enum df_ref_type, int ref_flags);
+static void df_insn_refs_collect (struct df_collection_rec*,
+				  basic_block, struct df_insn_info *);
+static void df_canonize_collection_rec (struct df_collection_rec *);
+
+static void df_get_regular_block_artificial_uses (bitmap);
+static void df_get_eh_block_artificial_uses (bitmap);
+
+static void df_record_entry_block_defs (bitmap);
+static void df_record_exit_block_uses (bitmap);
+static void df_get_exit_block_use_set (bitmap);
+static void df_get_entry_block_def_set (bitmap);
+static void df_grow_ref_info (struct df_ref_info *, unsigned int);
+static void df_ref_chain_delete_du_chain (df_ref *);
+static void df_ref_chain_delete (df_ref *);
+
+static void df_refs_add_to_chains (struct df_collection_rec *,
+				   basic_block, rtx, unsigned int);
+
+static bool df_insn_refs_verify (struct df_collection_rec *, basic_block, rtx, bool);
+static void df_entry_block_defs_collect (struct df_collection_rec *, bitmap);
+static void df_exit_block_uses_collect (struct df_collection_rec *, bitmap);
+static void df_install_ref (df_ref, struct df_reg_info *,
+			    struct df_ref_info *, bool);
+
+static int df_ref_compare (const void *, const void *);
+static int df_mw_compare (const void *, const void *);
+
+static void df_insn_info_delete (unsigned int);
+
+/* Indexed by hardware reg number, is true if that register is ever
+   used in the current function.
+
+   In df-scan.c, this is set up to record the hard regs used
+   explicitly.  Reload adds in the hard regs used for holding pseudo
+   regs.  Final uses it to generate the code in the function prologue
+   and epilogue to save and restore registers as needed.  */
+
+static bool regs_ever_live[FIRST_PSEUDO_REGISTER];
+
+/* Flags used to tell df_refs_add_to_chains() which vectors it should copy. */
+static const unsigned int copy_defs = 0x1;
+static const unsigned int copy_uses = 0x2;
+static const unsigned int copy_eq_uses = 0x4;
+static const unsigned int copy_mw = 0x8;
+static const unsigned int copy_all = copy_defs | copy_uses | copy_eq_uses
+| copy_mw;
+
+/*----------------------------------------------------------------------------
+   SCANNING DATAFLOW PROBLEM
+
+   There are several ways in which scanning looks just like the other
+   dataflow problems.  It shares the all the mechanisms for local info
+   as well as basic block info.  Where it differs is when and how often
+   it gets run.  It also has no need for the iterative solver.
+----------------------------------------------------------------------------*/
+
+/* Problem data for the scanning dataflow function.  */
+struct df_scan_problem_data
+{
+  alloc_pool ref_base_pool;
+  alloc_pool ref_artificial_pool;
+  alloc_pool ref_regular_pool;
+  alloc_pool insn_pool;
+  alloc_pool reg_pool;
+  alloc_pool mw_reg_pool;
+  bitmap_obstack reg_bitmaps;
+  bitmap_obstack insn_bitmaps;
+};
+
+typedef struct df_scan_bb_info *df_scan_bb_info_t;
+
+
+/* Internal function to shut down the scanning problem.  */
+static void
+df_scan_free_internal (void)
+{
+  struct df_scan_problem_data *problem_data
+    = (struct df_scan_problem_data *) df_scan->problem_data;
+  unsigned int i;
+  basic_block bb;
+
+  /* The vectors that hold the refs are not pool allocated because
+     they come in many sizes.  This makes them impossible to delete
+     all at once.  */
+  for (i = 0; i < DF_INSN_SIZE (); i++)
+    {
+      struct df_insn_info *insn_info = DF_INSN_UID_GET (i);
+      /* Skip the insns that have no insn_info or have been
+	 deleted.  */
+      if (insn_info)
+	{
+	  df_scan_free_ref_vec (insn_info->defs);
+	  df_scan_free_ref_vec (insn_info->uses);
+	  df_scan_free_ref_vec (insn_info->eq_uses);
+	  df_scan_free_mws_vec (insn_info->mw_hardregs);
+	}
+    }
+
+  FOR_ALL_BB_FN (bb, cfun)
+    {
+      unsigned int bb_index = bb->index;
+      struct df_scan_bb_info *bb_info = df_scan_get_bb_info (bb_index);
+      if (bb_info)
+	{
+	  df_scan_free_ref_vec (bb_info->artificial_defs);
+	  df_scan_free_ref_vec (bb_info->artificial_uses);
+	}
+    }
+
+  free (df->def_info.refs);
+  free (df->def_info.begin);
+  free (df->def_info.count);
+  memset (&df->def_info, 0, (sizeof (struct df_ref_info)));
+
+  free (df->use_info.refs);
+  free (df->use_info.begin);
+  free (df->use_info.count);
+  memset (&df->use_info, 0, (sizeof (struct df_ref_info)));
+
+  free (df->def_regs);
+  df->def_regs = NULL;
+  free (df->use_regs);
+  df->use_regs = NULL;
+  free (df->eq_use_regs);
+  df->eq_use_regs = NULL;
+  df->regs_size = 0;
+  DF_REG_SIZE (df) = 0;
+
+  free (df->insns);
+  df->insns = NULL;
+  DF_INSN_SIZE () = 0;
+
+  free (df_scan->block_info);
+  df_scan->block_info = NULL;
+  df_scan->block_info_size = 0;
+
+  bitmap_clear (&df->hardware_regs_used);
+  bitmap_clear (&df->regular_block_artificial_uses);
+  bitmap_clear (&df->eh_block_artificial_uses);
+  BITMAP_FREE (df->entry_block_defs);
+  BITMAP_FREE (df->exit_block_uses);
+  bitmap_clear (&df->insns_to_delete);
+  bitmap_clear (&df->insns_to_rescan);
+  bitmap_clear (&df->insns_to_notes_rescan);
+
+  free_alloc_pool (problem_data->ref_base_pool);
+  free_alloc_pool (problem_data->ref_artificial_pool);
+  free_alloc_pool (problem_data->ref_regular_pool);
+  free_alloc_pool (problem_data->insn_pool);
+  free_alloc_pool (problem_data->reg_pool);
+  free_alloc_pool (problem_data->mw_reg_pool);
+  bitmap_obstack_release (&problem_data->reg_bitmaps);
+  bitmap_obstack_release (&problem_data->insn_bitmaps);
+  free (df_scan->problem_data);
+}
+
+
+/* Free basic block info.  */
+
+static void
+df_scan_free_bb_info (basic_block bb, void *vbb_info)
+{
+  struct df_scan_bb_info *bb_info = (struct df_scan_bb_info *) vbb_info;
+  unsigned int bb_index = bb->index;
+
+  /* See if bb_info is initialized.  */
+  if (bb_info->artificial_defs)
+    {
+      rtx insn;
+      FOR_BB_INSNS (bb, insn)
+	{
+	  if (INSN_P (insn))
+	    df_insn_info_delete (INSN_UID (insn));
+	}
+
+      if (bb_index < df_scan->block_info_size)
+	bb_info = df_scan_get_bb_info (bb_index);
+
+      /* Get rid of any artificial uses or defs.  */
+      if (bb_info->artificial_defs)
+	{
+	  df_ref_chain_delete_du_chain (bb_info->artificial_defs);
+	  df_ref_chain_delete_du_chain (bb_info->artificial_uses);
+	  df_ref_chain_delete (bb_info->artificial_defs);
+	  df_ref_chain_delete (bb_info->artificial_uses);
+	  bb_info->artificial_defs = NULL;
+	  bb_info->artificial_uses = NULL;
+	}
+    }
+}
+
+
+/* Allocate the problem data for the scanning problem.  This should be
+   called when the problem is created or when the entire function is to
+   be rescanned.  */
+void
+df_scan_alloc (bitmap all_blocks ATTRIBUTE_UNUSED)
+{
+  struct df_scan_problem_data *problem_data;
+  unsigned int insn_num = get_max_uid () + 1;
+  unsigned int block_size = 512;
+  basic_block bb;
+
+  /* Given the number of pools, this is really faster than tearing
+     everything apart.  */
+  if (df_scan->problem_data)
+    df_scan_free_internal ();
+
+  problem_data = XNEW (struct df_scan_problem_data);
+  df_scan->problem_data = problem_data;
+  df_scan->computed = true;
+
+  problem_data->ref_base_pool
+    = create_alloc_pool ("df_scan ref base",
+			 sizeof (struct df_base_ref), block_size);
+  problem_data->ref_artificial_pool
+    = create_alloc_pool ("df_scan ref artificial",
+			 sizeof (struct df_artificial_ref), block_size);
+  problem_data->ref_regular_pool
+    = create_alloc_pool ("df_scan ref regular",
+			 sizeof (struct df_regular_ref), block_size);
+  problem_data->insn_pool
+    = create_alloc_pool ("df_scan insn",
+			 sizeof (struct df_insn_info), block_size);
+  problem_data->reg_pool
+    = create_alloc_pool ("df_scan reg",
+			 sizeof (struct df_reg_info), block_size);
+  problem_data->mw_reg_pool
+    = create_alloc_pool ("df_scan mw_reg",
+			 sizeof (struct df_mw_hardreg), block_size / 16);
+
+  bitmap_obstack_initialize (&problem_data->reg_bitmaps);
+  bitmap_obstack_initialize (&problem_data->insn_bitmaps);
+
+  insn_num += insn_num / 4;
+  df_grow_reg_info ();
+
+  df_grow_insn_info ();
+  df_grow_bb_info (df_scan);
+
+  FOR_ALL_BB_FN (bb, cfun)
+    {
+      unsigned int bb_index = bb->index;
+      struct df_scan_bb_info *bb_info = df_scan_get_bb_info (bb_index);
+      bb_info->artificial_defs = NULL;
+      bb_info->artificial_uses = NULL;
+    }
+
+  bitmap_initialize (&df->hardware_regs_used, &problem_data->reg_bitmaps);
+  bitmap_initialize (&df->regular_block_artificial_uses, &problem_data->reg_bitmaps);
+  bitmap_initialize (&df->eh_block_artificial_uses, &problem_data->reg_bitmaps);
+  df->entry_block_defs = BITMAP_ALLOC (&problem_data->reg_bitmaps);
+  df->exit_block_uses = BITMAP_ALLOC (&problem_data->reg_bitmaps);
+  bitmap_initialize (&df->insns_to_delete, &problem_data->insn_bitmaps);
+  bitmap_initialize (&df->insns_to_rescan, &problem_data->insn_bitmaps);
+  bitmap_initialize (&df->insns_to_notes_rescan, &problem_data->insn_bitmaps);
+  df_scan->optional_p = false;
+}
+
+
+/* Free all of the data associated with the scan problem.  */
+
+static void
+df_scan_free (void)
+{
+  if (df_scan->problem_data)
+    df_scan_free_internal ();
+
+  if (df->blocks_to_analyze)
+    {
+      BITMAP_FREE (df->blocks_to_analyze);
+      df->blocks_to_analyze = NULL;
+    }
+
+  free (df_scan);
+}
+
+/* Dump the preamble for DF_SCAN dump. */
+static void
+df_scan_start_dump (FILE *file ATTRIBUTE_UNUSED)
+{
+  int i;
+  int dcount = 0;
+  int ucount = 0;
+  int ecount = 0;
+  int icount = 0;
+  int ccount = 0;
+  basic_block bb;
+  rtx insn;
+
+  fprintf (file, ";;  invalidated by call \t");
+  df_print_regset (file, regs_invalidated_by_call_regset);
+  fprintf (file, ";;  hardware regs used \t");
+  df_print_regset (file, &df->hardware_regs_used);
+  fprintf (file, ";;  regular block artificial uses \t");
+  df_print_regset (file, &df->regular_block_artificial_uses);
+  fprintf (file, ";;  eh block artificial uses \t");
+  df_print_regset (file, &df->eh_block_artificial_uses);
+  fprintf (file, ";;  entry block defs \t");
+  df_print_regset (file, df->entry_block_defs);
+  fprintf (file, ";;  exit block uses \t");
+  df_print_regset (file, df->exit_block_uses);
+  fprintf (file, ";;  regs ever live \t");
+  for (i = 0; i < FIRST_PSEUDO_REGISTER; i++)
+    if (df_regs_ever_live_p (i))
+      fprintf (file, " %d[%s]", i, reg_names[i]);
+  fprintf (file, "\n;;  ref usage \t");
+
+  for (i = 0; i < (int)df->regs_inited; i++)
+    if (DF_REG_DEF_COUNT (i) || DF_REG_USE_COUNT (i) || DF_REG_EQ_USE_COUNT (i))
+      {
+	const char * sep = "";
+
+	fprintf (file, "r%d={", i);
+	if (DF_REG_DEF_COUNT (i))
+	  {
+	    fprintf (file, "%dd", DF_REG_DEF_COUNT (i));
+	    sep = ",";
+	    dcount += DF_REG_DEF_COUNT (i);
+	  }
+	if (DF_REG_USE_COUNT (i))
+	  {
+	    fprintf (file, "%s%du", sep, DF_REG_USE_COUNT (i));
+	    sep = ",";
+	    ucount += DF_REG_USE_COUNT (i);
+	  }
+	if (DF_REG_EQ_USE_COUNT (i))
+	  {
+	    fprintf (file, "%s%de", sep, DF_REG_EQ_USE_COUNT (i));
+	    ecount += DF_REG_EQ_USE_COUNT (i);
+	  }
+	fprintf (file, "} ");
+      }
+
+  FOR_EACH_BB_FN (bb, cfun)
+    FOR_BB_INSNS (bb, insn)
+      if (INSN_P (insn))
+	{
+	  if (CALL_P (insn))
+	    ccount++;
+	  else
+	    icount++;
+	}
+
+  fprintf (file, "\n;;    total ref usage %d{%dd,%du,%de}"
+		 " in %d{%d regular + %d call} insns.\n",
+		 dcount + ucount + ecount, dcount, ucount, ecount,
+		 icount + ccount, icount, ccount);
+}
+
+/* Dump the bb_info for a given basic block. */
+static void
+df_scan_start_block (basic_block bb, FILE *file)
+{
+  struct df_scan_bb_info *bb_info
+    = df_scan_get_bb_info (bb->index);
+
+  if (bb_info)
+    {
+      fprintf (file, ";; bb %d artificial_defs: ", bb->index);
+      df_refs_chain_dump (bb_info->artificial_defs, true, file);
+      fprintf (file, "\n;; bb %d artificial_uses: ", bb->index);
+      df_refs_chain_dump (bb_info->artificial_uses, true, file);
+      fprintf (file, "\n");
+    }
+#if 0
+  {
+    rtx insn;
+    FOR_BB_INSNS (bb, insn)
+      if (INSN_P (insn))
+	df_insn_debug (insn, false, file);
+  }
+#endif
+}
+
+static struct df_problem problem_SCAN =
+{
+  DF_SCAN,                    /* Problem id.  */
+  DF_NONE,                    /* Direction.  */
+  df_scan_alloc,              /* Allocate the problem specific data.  */
+  NULL,                       /* Reset global information.  */
+  df_scan_free_bb_info,       /* Free basic block info.  */
+  NULL,                       /* Local compute function.  */
+  NULL,                       /* Init the solution specific data.  */
+  NULL,                       /* Iterative solver.  */
+  NULL,                       /* Confluence operator 0.  */
+  NULL,                       /* Confluence operator n.  */
+  NULL,                       /* Transfer function.  */
+  NULL,                       /* Finalize function.  */
+  df_scan_free,               /* Free all of the problem information.  */
+  NULL,                       /* Remove this problem from the stack of dataflow problems.  */
+  df_scan_start_dump,         /* Debugging.  */
+  df_scan_start_block,        /* Debugging start block.  */
+  NULL,                       /* Debugging end block.  */
+  NULL,                       /* Debugging start insn.  */
+  NULL,                       /* Debugging end insn.  */
+  NULL,                       /* Incremental solution verify start.  */
+  NULL,                       /* Incremental solution verify end.  */
+  NULL,                       /* Dependent problem.  */
+  sizeof (struct df_scan_bb_info),/* Size of entry of block_info array.  */
+  TV_DF_SCAN,                 /* Timing variable.  */
+  false                       /* Reset blocks on dropping out of blocks_to_analyze.  */
+};
+
+
+/* Create a new DATAFLOW instance and add it to an existing instance
+   of DF.  The returned structure is what is used to get at the
+   solution.  */
+
+void
+df_scan_add_problem (void)
+{
+  df_add_problem (&problem_SCAN);
+}
+
+
+/*----------------------------------------------------------------------------
+   Storage Allocation Utilities
+----------------------------------------------------------------------------*/
+
+
+/* First, grow the reg_info information.  If the current size is less than
+   the number of pseudos, grow to 25% more than the number of
+   pseudos.
+
+   Second, assure that all of the slots up to max_reg_num have been
+   filled with reg_info structures.  */
+
+void
+df_grow_reg_info (void)
+{
+  unsigned int max_reg = max_reg_num ();
+  unsigned int new_size = max_reg;
+  struct df_scan_problem_data *problem_data
+    = (struct df_scan_problem_data *) df_scan->problem_data;
+  unsigned int i;
+
+  if (df->regs_size < new_size)
+    {
+      new_size += new_size / 4;
+      df->def_regs = XRESIZEVEC (struct df_reg_info *, df->def_regs, new_size);
+      df->use_regs = XRESIZEVEC (struct df_reg_info *, df->use_regs, new_size);
+      df->eq_use_regs = XRESIZEVEC (struct df_reg_info *, df->eq_use_regs,
+				    new_size);
+      df->def_info.begin = XRESIZEVEC (unsigned, df->def_info.begin, new_size);
+      df->def_info.count = XRESIZEVEC (unsigned, df->def_info.count, new_size);
+      df->use_info.begin = XRESIZEVEC (unsigned, df->use_info.begin, new_size);
+      df->use_info.count = XRESIZEVEC (unsigned, df->use_info.count, new_size);
+      df->regs_size = new_size;
+    }
+
+  for (i = df->regs_inited; i < max_reg; i++)
+    {
+      struct df_reg_info *reg_info;
+
+      reg_info = (struct df_reg_info *) pool_alloc (problem_data->reg_pool);
+      memset (reg_info, 0, sizeof (struct df_reg_info));
+      df->def_regs[i] = reg_info;
+      reg_info = (struct df_reg_info *) pool_alloc (problem_data->reg_pool);
+      memset (reg_info, 0, sizeof (struct df_reg_info));
+      df->use_regs[i] = reg_info;
+      reg_info = (struct df_reg_info *) pool_alloc (problem_data->reg_pool);
+      memset (reg_info, 0, sizeof (struct df_reg_info));
+      df->eq_use_regs[i] = reg_info;
+      df->def_info.begin[i] = 0;
+      df->def_info.count[i] = 0;
+      df->use_info.begin[i] = 0;
+      df->use_info.count[i] = 0;
+    }
+
+  df->regs_inited = max_reg;
+}
+
+
+/* Grow the ref information.  */
+
+static void
+df_grow_ref_info (struct df_ref_info *ref_info, unsigned int new_size)
+{
+  if (ref_info->refs_size < new_size)
+    {
+      ref_info->refs = XRESIZEVEC (df_ref, ref_info->refs, new_size);
+      memset (ref_info->refs + ref_info->refs_size, 0,
+	      (new_size - ref_info->refs_size) *sizeof (df_ref));
+      ref_info->refs_size = new_size;
+    }
+}
+
+
+/* Check and grow the ref information if necessary.  This routine
+   guarantees total_size + BITMAP_ADDEND amount of entries in refs
+   array.  It updates ref_info->refs_size only and does not change
+   ref_info->total_size.  */
+
+static void
+df_check_and_grow_ref_info (struct df_ref_info *ref_info,
+			    unsigned bitmap_addend)
+{
+  if (ref_info->refs_size < ref_info->total_size + bitmap_addend)
+    {
+      int new_size = ref_info->total_size + bitmap_addend;
+      new_size += ref_info->total_size / 4;
+      df_grow_ref_info (ref_info, new_size);
+    }
+}
+
+
+/* Grow the ref information.  If the current size is less than the
+   number of instructions, grow to 25% more than the number of
+   instructions.  */
+
+void
+df_grow_insn_info (void)
+{
+  unsigned int new_size = get_max_uid () + 1;
+  if (DF_INSN_SIZE () < new_size)
+    {
+      new_size += new_size / 4;
+      df->insns = XRESIZEVEC (struct df_insn_info *, df->insns, new_size);
+      memset (df->insns + df->insns_size, 0,
+	      (new_size - DF_INSN_SIZE ()) *sizeof (struct df_insn_info *));
+      DF_INSN_SIZE () = new_size;
+    }
+}
+
+
+
+
+/*----------------------------------------------------------------------------
+   PUBLIC INTERFACES FOR SMALL GRAIN CHANGES TO SCANNING.
+----------------------------------------------------------------------------*/
+
+/* Rescan all of the block_to_analyze or all of the blocks in the
+   function if df_set_blocks if blocks_to_analyze is NULL;  */
+
+void
+df_scan_blocks (void)
+{
+  basic_block bb;
+
+  df->def_info.ref_order = DF_REF_ORDER_NO_TABLE;
+  df->use_info.ref_order = DF_REF_ORDER_NO_TABLE;
+
+  df_get_regular_block_artificial_uses (&df->regular_block_artificial_uses);
+  df_get_eh_block_artificial_uses (&df->eh_block_artificial_uses);
+
+  bitmap_ior_into (&df->eh_block_artificial_uses,
+		   &df->regular_block_artificial_uses);
+
+  /* ENTRY and EXIT blocks have special defs/uses.  */
+  df_get_entry_block_def_set (df->entry_block_defs);
+  df_record_entry_block_defs (df->entry_block_defs);
+  df_get_exit_block_use_set (df->exit_block_uses);
+  df_record_exit_block_uses (df->exit_block_uses);
+  df_set_bb_dirty (BASIC_BLOCK_FOR_FN (cfun, ENTRY_BLOCK));
+  df_set_bb_dirty (BASIC_BLOCK_FOR_FN (cfun, EXIT_BLOCK));
+
+  /* Regular blocks */
+  FOR_EACH_BB_FN (bb, cfun)
+    {
+      unsigned int bb_index = bb->index;
+      df_bb_refs_record (bb_index, true);
+    }
+}
+
+/* Create new refs under address LOC within INSN.  This function is
+   only used externally.  REF_FLAGS must be either 0 or DF_REF_IN_NOTE,
+   depending on whether LOC is inside PATTERN (INSN) or a note.  */
+
+void
+df_uses_create (rtx *loc, rtx insn, int ref_flags)
+{
+  gcc_assert (!(ref_flags & ~DF_REF_IN_NOTE));
+  df_uses_record (NULL, loc, DF_REF_REG_USE,
+                  BLOCK_FOR_INSN (insn),
+                  DF_INSN_INFO_GET (insn),
+                  ref_flags);
+}
+
+/* Create a new ref of type DF_REF_TYPE for register REG at address
+   LOC within INSN of BB.  This function is only used externally.  */
+
+df_ref
+df_ref_create (rtx reg, rtx *loc, rtx insn,
+	       basic_block bb,
+	       enum df_ref_type ref_type,
+	       int ref_flags)
+{
+  enum df_ref_class cl;
+
+  df_grow_reg_info ();
+
+  /* You cannot hack artificial refs.  */
+  gcc_assert (insn);
+
+  if (loc)
+    cl = DF_REF_REGULAR;
+  else
+    cl = DF_REF_BASE;
+
+  return df_ref_create_structure (cl, NULL, reg, loc, bb,
+                                  DF_INSN_INFO_GET (insn),
+                                  ref_type, ref_flags);
+}
+
+static void
+df_install_ref_incremental (df_ref ref)
+{
+  struct df_reg_info **reg_info;
+  struct df_ref_info *ref_info;
+  df_ref *ref_rec;
+  df_ref **ref_rec_ptr;
+  unsigned int count = 0;
+  bool add_to_table;
+
+  rtx insn = DF_REF_INSN (ref);
+  basic_block bb = BLOCK_FOR_INSN (insn);
+
+  if (DF_REF_REG_DEF_P (ref))
+    {
+      reg_info = df->def_regs;
+      ref_info = &df->def_info;
+      ref_rec_ptr = &DF_INSN_DEFS (insn);
+      add_to_table = ref_info->ref_order != DF_REF_ORDER_NO_TABLE;
+    }
+  else if (DF_REF_FLAGS (ref) & DF_REF_IN_NOTE)
+    {
+      reg_info = df->eq_use_regs;
+      ref_info = &df->use_info;
+      ref_rec_ptr = &DF_INSN_EQ_USES (insn);
+      switch (ref_info->ref_order)
+	{
+	case DF_REF_ORDER_UNORDERED_WITH_NOTES:
+	case DF_REF_ORDER_BY_REG_WITH_NOTES:
+	case DF_REF_ORDER_BY_INSN_WITH_NOTES:
+	  add_to_table = true;
+	  break;
+	default:
+	  add_to_table = false;
+	  break;
+	}
+    }
+  else
+    {
+      reg_info = df->use_regs;
+      ref_info = &df->use_info;
+      ref_rec_ptr = &DF_INSN_USES (insn);
+      add_to_table = ref_info->ref_order != DF_REF_ORDER_NO_TABLE;
+    }
+
+  /* Do not add if ref is not in the right blocks.  */
+  if (add_to_table && df->analyze_subset)
+    add_to_table = bitmap_bit_p (df->blocks_to_analyze, bb->index);
+
+  df_install_ref (ref, reg_info[DF_REF_REGNO (ref)], ref_info, add_to_table);
+
+  if (add_to_table)
+    switch (ref_info->ref_order)
+      {
+      case DF_REF_ORDER_UNORDERED_WITH_NOTES:
+      case DF_REF_ORDER_BY_REG_WITH_NOTES:
+      case DF_REF_ORDER_BY_INSN_WITH_NOTES:
+	ref_info->ref_order = DF_REF_ORDER_UNORDERED_WITH_NOTES;
+	break;
+      default:
+	ref_info->ref_order = DF_REF_ORDER_UNORDERED;
+	break;
+      }
+
+  ref_rec = *ref_rec_ptr;
+  while (*ref_rec)
+    {
+      count++;
+      ref_rec++;
+    }
+
+  ref_rec = *ref_rec_ptr;
+  if (count)
+    {
+      ref_rec = XRESIZEVEC (df_ref, ref_rec, count+2);
+      *ref_rec_ptr = ref_rec;
+      ref_rec[count] = ref;
+      ref_rec[count+1] = NULL;
+      qsort (ref_rec, count + 1, sizeof (df_ref), df_ref_compare);
+    }
+  else
+    {
+      df_ref *ref_rec = XNEWVEC (df_ref, 2);
+      ref_rec[0] = ref;
+      ref_rec[1] = NULL;
+      *ref_rec_ptr = ref_rec;
+    }
+
+#if 0
+  if (dump_file)
+    {
+      fprintf (dump_file, "adding ref ");
+      df_ref_debug (ref, dump_file);
+    }
+#endif
+  /* By adding the ref directly, df_insn_rescan my not find any
+     differences even though the block will have changed.  So we need
+     to mark the block dirty ourselves.  */
+  if (!DEBUG_INSN_P (DF_REF_INSN (ref)))
+    df_set_bb_dirty (bb);
+}
+
+
+
+/*----------------------------------------------------------------------------
+   UTILITIES TO CREATE AND DESTROY REFS AND CHAINS.
+----------------------------------------------------------------------------*/
+
+static void
+df_free_ref (df_ref ref)
+{
+  struct df_scan_problem_data *problem_data
+    = (struct df_scan_problem_data *) df_scan->problem_data;
+
+  switch (DF_REF_CLASS (ref))
+    {
+    case DF_REF_BASE:
+      pool_free (problem_data->ref_base_pool, ref);
+      break;
+
+    case DF_REF_ARTIFICIAL:
+      pool_free (problem_data->ref_artificial_pool, ref);
+      break;
+
+    case DF_REF_REGULAR:
+      pool_free (problem_data->ref_regular_pool, ref);
+      break;
+    }
+}
+
+
+/* Unlink and delete REF at the reg_use, reg_eq_use or reg_def chain.
+   Also delete the def-use or use-def chain if it exists.  */
+
+static void
+df_reg_chain_unlink (df_ref ref)
+{
+  df_ref next = DF_REF_NEXT_REG (ref);
+  df_ref prev = DF_REF_PREV_REG (ref);
+  int id = DF_REF_ID (ref);
+  struct df_reg_info *reg_info;
+  df_ref *refs = NULL;
+
+  if (DF_REF_REG_DEF_P (ref))
+    {
+      int regno = DF_REF_REGNO (ref);
+      reg_info = DF_REG_DEF_GET (regno);
+      refs = df->def_info.refs;
+    }
+  else
+    {
+      if (DF_REF_FLAGS (ref) & DF_REF_IN_NOTE)
+	{
+	  reg_info = DF_REG_EQ_USE_GET (DF_REF_REGNO (ref));
+	  switch (df->use_info.ref_order)
+	    {
+	    case DF_REF_ORDER_UNORDERED_WITH_NOTES:
+	    case DF_REF_ORDER_BY_REG_WITH_NOTES:
+	    case DF_REF_ORDER_BY_INSN_WITH_NOTES:
+	      refs = df->use_info.refs;
+	      break;
+	    default:
+	      break;
+	    }
+	}
+      else
+	{
+	  reg_info = DF_REG_USE_GET (DF_REF_REGNO (ref));
+	  refs = df->use_info.refs;
+	}
+    }
+
+  if (refs)
+    {
+      if (df->analyze_subset)
+	{
+	  if (bitmap_bit_p (df->blocks_to_analyze, DF_REF_BBNO (ref)))
+	    refs[id] = NULL;
+	}
+      else
+	refs[id] = NULL;
+    }
+
+  /* Delete any def-use or use-def chains that start here. It is
+     possible that there is trash in this field.  This happens for
+     insns that have been deleted when rescanning has been deferred
+     and the chain problem has also been deleted.  The chain tear down
+     code skips deleted insns.  */
+  if (df_chain && DF_REF_CHAIN (ref))
+    df_chain_unlink (ref);
+
+  reg_info->n_refs--;
+  if (DF_REF_FLAGS_IS_SET (ref, DF_HARD_REG_LIVE))
+    {
+      gcc_assert (DF_REF_REGNO (ref) < FIRST_PSEUDO_REGISTER);
+      df->hard_regs_live_count[DF_REF_REGNO (ref)]--;
+    }
+
+  /* Unlink from the reg chain.  If there is no prev, this is the
+     first of the list.  If not, just join the next and prev.  */
+  if (prev)
+    DF_REF_NEXT_REG (prev) = next;
+  else
+    {
+      gcc_assert (reg_info->reg_chain == ref);
+      reg_info->reg_chain = next;
+    }
+  if (next)
+    DF_REF_PREV_REG (next) = prev;
+
+  df_free_ref (ref);
+}
+
+
+/* Remove REF from VEC.  */
+
+static void
+df_ref_compress_rec (df_ref **vec_ptr, df_ref ref)
+{
+  df_ref *vec = *vec_ptr;
+
+  if (vec[1])
+    {
+      while (*vec && *vec != ref)
+	vec++;
+
+      while (*vec)
+	{
+	  *vec = *(vec+1);
+	  vec++;
+	}
+    }
+  else
+    {
+      free (vec);
+      *vec_ptr = df_null_ref_rec;
+    }
+}
+
+
+/* Unlink REF from all def-use/use-def chains, etc.  */
+
+void
+df_ref_remove (df_ref ref)
+{
+#if 0
+  if (dump_file)
+    {
+      fprintf (dump_file, "removing ref ");
+      df_ref_debug (ref, dump_file);
+    }
+#endif
+
+  if (DF_REF_REG_DEF_P (ref))
+    {
+      if (DF_REF_IS_ARTIFICIAL (ref))
+	{
+	  struct df_scan_bb_info *bb_info
+	    = df_scan_get_bb_info (DF_REF_BBNO (ref));
+	  df_ref_compress_rec (&bb_info->artificial_defs, ref);
+	}
+      else
+	{
+	  unsigned int uid = DF_REF_INSN_UID (ref);
+	  struct df_insn_info *insn_rec = DF_INSN_UID_GET (uid);
+	  df_ref_compress_rec (&insn_rec->defs, ref);
+	}
+    }
+  else
+    {
+      if (DF_REF_IS_ARTIFICIAL (ref))
+	{
+	  struct df_scan_bb_info *bb_info
+	    = df_scan_get_bb_info (DF_REF_BBNO (ref));
+	  df_ref_compress_rec (&bb_info->artificial_uses, ref);
+	}
+      else
+	{
+	  unsigned int uid = DF_REF_INSN_UID (ref);
+	  struct df_insn_info *insn_rec = DF_INSN_UID_GET (uid);
+
+	  if (DF_REF_FLAGS (ref) & DF_REF_IN_NOTE)
+	    df_ref_compress_rec (&insn_rec->eq_uses, ref);
+	  else
+	    df_ref_compress_rec (&insn_rec->uses, ref);
+	}
+    }
+
+  /* By deleting the ref directly, df_insn_rescan my not find any
+     differences even though the block will have changed.  So we need
+     to mark the block dirty ourselves.  */
+  if (!DEBUG_INSN_P (DF_REF_INSN (ref)))
+    df_set_bb_dirty (DF_REF_BB (ref));
+  df_reg_chain_unlink (ref);
+}
+
+
+/* Create the insn record for INSN.  If there was one there, zero it
+   out.  */
+
+struct df_insn_info *
+df_insn_create_insn_record (rtx insn)
+{
+  struct df_scan_problem_data *problem_data
+    = (struct df_scan_problem_data *) df_scan->problem_data;
+  struct df_insn_info *insn_rec;
+
+  df_grow_insn_info ();
+  insn_rec = DF_INSN_INFO_GET (insn);
+  if (!insn_rec)
+    {
+      insn_rec = (struct df_insn_info *) pool_alloc (problem_data->insn_pool);
+      DF_INSN_INFO_SET (insn, insn_rec);
+    }
+  memset (insn_rec, 0, sizeof (struct df_insn_info));
+  insn_rec->insn = insn;
+  return insn_rec;
+}
+
+
+/* Delete all du chain (DF_REF_CHAIN()) of all refs in the ref chain.  */
+
+static void
+df_ref_chain_delete_du_chain (df_ref *ref_rec)
+{
+  while (*ref_rec)
+    {
+      df_ref ref = *ref_rec;
+      /* CHAIN is allocated by DF_CHAIN. So make sure to
+         pass df_scan instance for the problem.  */
+      if (DF_REF_CHAIN (ref))
+        df_chain_unlink (ref);
+      ref_rec++;
+    }
+}
+
+
+/* Delete all refs in the ref chain.  */
+
+static void
+df_ref_chain_delete (df_ref *ref_rec)
+{
+  df_ref *start = ref_rec;
+  while (*ref_rec)
+    {
+      df_reg_chain_unlink (*ref_rec);
+      ref_rec++;
+    }
+
+  /* If the list is empty, it has a special shared element that is not
+     to be deleted.  */
+  if (*start)
+    free (start);
+}
+
+
+/* Delete the hardreg chain.  */
+
+static void
+df_mw_hardreg_chain_delete (struct df_mw_hardreg **hardregs)
+{
+  struct df_scan_problem_data *problem_data;
+
+  if (!hardregs)
+    return;
+
+  problem_data = (struct df_scan_problem_data *) df_scan->problem_data;
+
+  while (*hardregs)
+    {
+      pool_free (problem_data->mw_reg_pool, *hardregs);
+      hardregs++;
+    }
+}
+
+
+/* Delete all of the refs information from the insn with UID.
+   Internal helper for df_insn_delete, df_insn_rescan, and other
+   df-scan routines that don't have to work in deferred mode
+   and do not have to mark basic blocks for re-processing.  */
+
+static void
+df_insn_info_delete (unsigned int uid)
+{
+  struct df_insn_info *insn_info = DF_INSN_UID_SAFE_GET (uid);
+
+  bitmap_clear_bit (&df->insns_to_delete, uid);
+  bitmap_clear_bit (&df->insns_to_rescan, uid);
+  bitmap_clear_bit (&df->insns_to_notes_rescan, uid);
+  if (insn_info)
+    {
+      struct df_scan_problem_data *problem_data
+	= (struct df_scan_problem_data *) df_scan->problem_data;
+
+      /* In general, notes do not have the insn_info fields
+	 initialized.  However, combine deletes insns by changing them
+	 to notes.  How clever.  So we cannot just check if it is a
+	 valid insn before short circuiting this code, we need to see
+	 if we actually initialized it.  */
+      if (insn_info->defs)
+	{
+	  df_mw_hardreg_chain_delete (insn_info->mw_hardregs);
+
+	  if (df_chain)
+	    {
+	      df_ref_chain_delete_du_chain (insn_info->defs);
+	      df_ref_chain_delete_du_chain (insn_info->uses);
+	      df_ref_chain_delete_du_chain (insn_info->eq_uses);
+	    }
+
+	  df_ref_chain_delete (insn_info->defs);
+	  df_ref_chain_delete (insn_info->uses);
+	  df_ref_chain_delete (insn_info->eq_uses);
+	  df_scan_free_mws_vec (insn_info->mw_hardregs);
+	}
+      pool_free (problem_data->insn_pool, insn_info);
+      DF_INSN_UID_SET (uid, NULL);
+    }
+}
+
+/* Delete all of the refs information from INSN, either right now
+   or marked for later in deferred mode.  */
+
+void
+df_insn_delete (rtx insn)
+{
+  unsigned int uid;
+  basic_block bb;
+
+  gcc_checking_assert (INSN_P (insn));
+
+  if (!df)
+    return;
+
+  uid = INSN_UID (insn);
+  bb = BLOCK_FOR_INSN (insn);
+
+  /* ??? bb can be NULL after pass_free_cfg.  At that point, DF should
+     not exist anymore (as mentioned in df-core.c: "The only requirement
+     [for DF] is that there be a correct control flow graph."  Clearly
+     that isn't the case after pass_free_cfg.  But DF is freed much later
+     because some back-ends want to use DF info even though the CFG is
+     already gone.  It's not clear to me whether that is safe, actually.
+     In any case, we expect BB to be non-NULL at least up to register
+     allocation, so disallow a non-NULL BB up to there.  Not perfect
+     but better than nothing...  */
+  gcc_checking_assert (bb != NULL || reload_completed);
+
+  df_grow_bb_info (df_scan);
+  df_grow_reg_info ();
+
+  /* The block must be marked as dirty now, rather than later as in
+     df_insn_rescan and df_notes_rescan because it may not be there at
+     rescanning time and the mark would blow up.
+     DEBUG_INSNs do not make a block's data flow solution dirty (at
+     worst the LUIDs are no longer contiguous).  */
+  if (bb != NULL && NONDEBUG_INSN_P (insn))
+    df_set_bb_dirty (bb);
+
+  /* The client has deferred rescanning.  */
+  if (df->changeable_flags & DF_DEFER_INSN_RESCAN)
+    {
+      struct df_insn_info *insn_info = DF_INSN_UID_SAFE_GET (uid);
+      if (insn_info)
+	{
+	  bitmap_clear_bit (&df->insns_to_rescan, uid);
+	  bitmap_clear_bit (&df->insns_to_notes_rescan, uid);
+	  bitmap_set_bit (&df->insns_to_delete, uid);
+	}
+      if (dump_file)
+	fprintf (dump_file, "deferring deletion of insn with uid = %d.\n", uid);
+      return;
+    }
+
+  if (dump_file)
+    fprintf (dump_file, "deleting insn with uid = %d.\n", uid);
+
+  df_insn_info_delete (uid);
+}
+
+
+/* Free all of the refs and the mw_hardregs in COLLECTION_REC.  */
+
+static void
+df_free_collection_rec (struct df_collection_rec *collection_rec)
+{
+  unsigned int ix;
+  struct df_scan_problem_data *problem_data
+    = (struct df_scan_problem_data *) df_scan->problem_data;
+  df_ref ref;
+  struct df_mw_hardreg *mw;
+
+  FOR_EACH_VEC_ELT (collection_rec->def_vec, ix, ref)
+    df_free_ref (ref);
+  FOR_EACH_VEC_ELT (collection_rec->use_vec, ix, ref)
+    df_free_ref (ref);
+  FOR_EACH_VEC_ELT (collection_rec->eq_use_vec, ix, ref)
+    df_free_ref (ref);
+  FOR_EACH_VEC_ELT (collection_rec->mw_vec, ix, mw)
+    pool_free (problem_data->mw_reg_pool, mw);
+
+  collection_rec->def_vec.release ();
+  collection_rec->use_vec.release ();
+  collection_rec->eq_use_vec.release ();
+  collection_rec->mw_vec.release ();
+}
+
+/* Rescan INSN.  Return TRUE if the rescanning produced any changes.  */
+
+bool
+df_insn_rescan (rtx insn)
+{
+  unsigned int uid = INSN_UID (insn);
+  struct df_insn_info *insn_info = NULL;
+  basic_block bb = BLOCK_FOR_INSN (insn);
+  struct df_collection_rec collection_rec;
+
+  if ((!df) || (!INSN_P (insn)))
+    return false;
+
+  if (!bb)
+    {
+      if (dump_file)
+	fprintf (dump_file, "no bb for insn with uid = %d.\n", uid);
+      return false;
+    }
+
+  /* The client has disabled rescanning and plans to do it itself.  */
+  if (df->changeable_flags & DF_NO_INSN_RESCAN)
+    return false;
+
+  df_grow_bb_info (df_scan);
+  df_grow_reg_info ();
+
+  insn_info = DF_INSN_UID_SAFE_GET (uid);
+
+  /* The client has deferred rescanning.  */
+  if (df->changeable_flags & DF_DEFER_INSN_RESCAN)
+    {
+      if (!insn_info)
+	{
+	  insn_info = df_insn_create_insn_record (insn);
+	  insn_info->defs = df_null_ref_rec;
+	  insn_info->uses = df_null_ref_rec;
+	  insn_info->eq_uses = df_null_ref_rec;
+	  insn_info->mw_hardregs = df_null_mw_rec;
+	}
+      if (dump_file)
+	fprintf (dump_file, "deferring rescan insn with uid = %d.\n", uid);
+
+      bitmap_clear_bit (&df->insns_to_delete, uid);
+      bitmap_clear_bit (&df->insns_to_notes_rescan, uid);
+      bitmap_set_bit (&df->insns_to_rescan, INSN_UID (insn));
+      return false;
+    }
+
+  bitmap_clear_bit (&df->insns_to_delete, uid);
+  bitmap_clear_bit (&df->insns_to_rescan, uid);
+  bitmap_clear_bit (&df->insns_to_notes_rescan, uid);
+  if (insn_info)
+    {
+      int luid;
+      bool the_same = df_insn_refs_verify (&collection_rec, bb, insn, false);
+      /* If there's no change, return false. */
+      if (the_same)
+	{
+	  df_free_collection_rec (&collection_rec);
+	  if (dump_file)
+	    fprintf (dump_file, "verify found no changes in insn with uid = %d.\n", uid);
+	  return false;
+	}
+      if (dump_file)
+	fprintf (dump_file, "rescanning insn with uid = %d.\n", uid);
+
+      /* There's change - we need to delete the existing info.
+	 Since the insn isn't moved, we can salvage its LUID.  */
+      luid = DF_INSN_LUID (insn);
+      df_insn_info_delete (uid);
+      df_insn_create_insn_record (insn);
+      DF_INSN_LUID (insn) = luid;
+    }
+  else
+    {
+      struct df_insn_info *insn_info = df_insn_create_insn_record (insn);
+      df_insn_refs_collect (&collection_rec, bb, insn_info);
+      if (dump_file)
+	fprintf (dump_file, "scanning new insn with uid = %d.\n", uid);
+    }
+
+  df_refs_add_to_chains (&collection_rec, bb, insn, copy_all);
+  if (!DEBUG_INSN_P (insn))
+    df_set_bb_dirty (bb);
+
+  return true;
+}
+
+/* Same as df_insn_rescan, but don't mark the basic block as
+   dirty.  */
+
+bool
+df_insn_rescan_debug_internal (rtx insn)
+{
+  unsigned int uid = INSN_UID (insn);
+  struct df_insn_info *insn_info;
+
+  gcc_assert (DEBUG_INSN_P (insn)
+	      && VAR_LOC_UNKNOWN_P (INSN_VAR_LOCATION_LOC (insn)));
+
+  if (!df)
+    return false;
+
+  insn_info = DF_INSN_UID_SAFE_GET (INSN_UID (insn));
+  if (!insn_info)
+    return false;
+
+  if (dump_file)
+    fprintf (dump_file, "deleting debug_insn with uid = %d.\n", uid);
+
+  bitmap_clear_bit (&df->insns_to_delete, uid);
+  bitmap_clear_bit (&df->insns_to_rescan, uid);
+  bitmap_clear_bit (&df->insns_to_notes_rescan, uid);
+
+  if (!insn_info->defs)
+    return false;
+
+  if (insn_info->defs == df_null_ref_rec
+      && insn_info->uses == df_null_ref_rec
+      && insn_info->eq_uses == df_null_ref_rec
+      && insn_info->mw_hardregs == df_null_mw_rec)
+    return false;
+
+  df_mw_hardreg_chain_delete (insn_info->mw_hardregs);
+
+  if (df_chain)
+    {
+      df_ref_chain_delete_du_chain (insn_info->defs);
+      df_ref_chain_delete_du_chain (insn_info->uses);
+      df_ref_chain_delete_du_chain (insn_info->eq_uses);
+    }
+
+  df_ref_chain_delete (insn_info->defs);
+  df_ref_chain_delete (insn_info->uses);
+  df_ref_chain_delete (insn_info->eq_uses);
+  df_scan_free_mws_vec (insn_info->mw_hardregs);
+
+  insn_info->defs = df_null_ref_rec;
+  insn_info->uses = df_null_ref_rec;
+  insn_info->eq_uses = df_null_ref_rec;
+  insn_info->mw_hardregs = df_null_mw_rec;
+
+  return true;
+}
+
+
+/* Rescan all of the insns in the function.  Note that the artificial
+   uses and defs are not touched.  This function will destroy def-use
+   or use-def chains.  */
+
+void
+df_insn_rescan_all (void)
+{
+  bool no_insn_rescan = false;
+  bool defer_insn_rescan = false;
+  basic_block bb;
+  bitmap_iterator bi;
+  unsigned int uid;
+  bitmap_head tmp;
+
+  bitmap_initialize (&tmp, &df_bitmap_obstack);
+
+  if (df->changeable_flags & DF_NO_INSN_RESCAN)
+    {
+      df_clear_flags (DF_NO_INSN_RESCAN);
+      no_insn_rescan = true;
+    }
+
+  if (df->changeable_flags & DF_DEFER_INSN_RESCAN)
+    {
+      df_clear_flags (DF_DEFER_INSN_RESCAN);
+      defer_insn_rescan = true;
+    }
+
+  bitmap_copy (&tmp, &df->insns_to_delete);
+  EXECUTE_IF_SET_IN_BITMAP (&tmp, 0, uid, bi)
+    {
+      struct df_insn_info *insn_info = DF_INSN_UID_SAFE_GET (uid);
+      if (insn_info)
+	df_insn_info_delete (uid);
+    }
+
+  bitmap_clear (&tmp);
+  bitmap_clear (&df->insns_to_delete);
+  bitmap_clear (&df->insns_to_rescan);
+  bitmap_clear (&df->insns_to_notes_rescan);
+
+  FOR_EACH_BB_FN (bb, cfun)
+    {
+      rtx insn;
+      FOR_BB_INSNS (bb, insn)
+	{
+	  df_insn_rescan (insn);
+	}
+    }
+
+  if (no_insn_rescan)
+    df_set_flags (DF_NO_INSN_RESCAN);
+  if (defer_insn_rescan)
+    df_set_flags (DF_DEFER_INSN_RESCAN);
+}
+
+
+/* Process all of the deferred rescans or deletions.  */
+
+void
+df_process_deferred_rescans (void)
+{
+  bool no_insn_rescan = false;
+  bool defer_insn_rescan = false;
+  bitmap_iterator bi;
+  unsigned int uid;
+  bitmap_head tmp;
+
+  bitmap_initialize (&tmp, &df_bitmap_obstack);
+
+  if (df->changeable_flags & DF_NO_INSN_RESCAN)
+    {
+      df_clear_flags (DF_NO_INSN_RESCAN);
+      no_insn_rescan = true;
+    }
+
+  if (df->changeable_flags & DF_DEFER_INSN_RESCAN)
+    {
+      df_clear_flags (DF_DEFER_INSN_RESCAN);
+      defer_insn_rescan = true;
+    }
+
+  if (dump_file)
+    fprintf (dump_file, "starting the processing of deferred insns\n");
+
+  bitmap_copy (&tmp, &df->insns_to_delete);
+  EXECUTE_IF_SET_IN_BITMAP (&tmp, 0, uid, bi)
+    {
+      struct df_insn_info *insn_info = DF_INSN_UID_SAFE_GET (uid);
+      if (insn_info)
+	df_insn_info_delete (uid);
+    }
+
+  bitmap_copy (&tmp, &df->insns_to_rescan);
+  EXECUTE_IF_SET_IN_BITMAP (&tmp, 0, uid, bi)
+    {
+      struct df_insn_info *insn_info = DF_INSN_UID_SAFE_GET (uid);
+      if (insn_info)
+	df_insn_rescan (insn_info->insn);
+    }
+
+  bitmap_copy (&tmp, &df->insns_to_notes_rescan);
+  EXECUTE_IF_SET_IN_BITMAP (&tmp, 0, uid, bi)
+    {
+      struct df_insn_info *insn_info = DF_INSN_UID_SAFE_GET (uid);
+      if (insn_info)
+	df_notes_rescan (insn_info->insn);
+    }
+
+  if (dump_file)
+    fprintf (dump_file, "ending the processing of deferred insns\n");
+
+  bitmap_clear (&tmp);
+  bitmap_clear (&df->insns_to_delete);
+  bitmap_clear (&df->insns_to_rescan);
+  bitmap_clear (&df->insns_to_notes_rescan);
+
+  if (no_insn_rescan)
+    df_set_flags (DF_NO_INSN_RESCAN);
+  if (defer_insn_rescan)
+    df_set_flags (DF_DEFER_INSN_RESCAN);
+
+  /* If someone changed regs_ever_live during this pass, fix up the
+     entry and exit blocks.  */
+  if (df->redo_entry_and_exit)
+    {
+      df_update_entry_exit_and_calls ();
+      df->redo_entry_and_exit = false;
+    }
+}
+
+
+/* Count the number of refs. Include the defs if INCLUDE_DEFS. Include
+   the uses if INCLUDE_USES. Include the eq_uses if
+   INCLUDE_EQ_USES.  */
+
+static unsigned int
+df_count_refs (bool include_defs, bool include_uses,
+	       bool include_eq_uses)
+{
+  unsigned int regno;
+  int size = 0;
+  unsigned int m = df->regs_inited;
+
+  for (regno = 0; regno < m; regno++)
+    {
+      if (include_defs)
+	size += DF_REG_DEF_COUNT (regno);
+      if (include_uses)
+	size += DF_REG_USE_COUNT (regno);
+      if (include_eq_uses)
+	size += DF_REG_EQ_USE_COUNT (regno);
+    }
+  return size;
+}
+
+
+/* Take build ref table for either the uses or defs from the reg-use
+   or reg-def chains.  This version processes the refs in reg order
+   which is likely to be best if processing the whole function.  */
+
+static void
+df_reorganize_refs_by_reg_by_reg (struct df_ref_info *ref_info,
+				  bool include_defs,
+				  bool include_uses,
+				  bool include_eq_uses)
+{
+  unsigned int m = df->regs_inited;
+  unsigned int regno;
+  unsigned int offset = 0;
+  unsigned int start;
+
+  if (df->changeable_flags & DF_NO_HARD_REGS)
+    {
+      start = FIRST_PSEUDO_REGISTER;
+      memset (ref_info->begin, 0, sizeof (int) * FIRST_PSEUDO_REGISTER);
+      memset (ref_info->count, 0, sizeof (int) * FIRST_PSEUDO_REGISTER);
+    }
+  else
+    start = 0;
+
+  ref_info->total_size
+    = df_count_refs (include_defs, include_uses, include_eq_uses);
+
+  df_check_and_grow_ref_info (ref_info, 1);
+
+  for (regno = start; regno < m; regno++)
+    {
+      int count = 0;
+      ref_info->begin[regno] = offset;
+      if (include_defs)
+	{
+	  df_ref ref = DF_REG_DEF_CHAIN (regno);
+	  while (ref)
+	    {
+	      ref_info->refs[offset] = ref;
+	      DF_REF_ID (ref) = offset++;
+	      count++;
+	      ref = DF_REF_NEXT_REG (ref);
+	      gcc_checking_assert (offset < ref_info->refs_size);
+	    }
+	}
+      if (include_uses)
+	{
+	  df_ref ref = DF_REG_USE_CHAIN (regno);
+	  while (ref)
+	    {
+	      ref_info->refs[offset] = ref;
+	      DF_REF_ID (ref) = offset++;
+	      count++;
+	      ref = DF_REF_NEXT_REG (ref);
+	      gcc_checking_assert (offset < ref_info->refs_size);
+	    }
+	}
+      if (include_eq_uses)
+	{
+	  df_ref ref = DF_REG_EQ_USE_CHAIN (regno);
+	  while (ref)
+	    {
+	      ref_info->refs[offset] = ref;
+	      DF_REF_ID (ref) = offset++;
+	      count++;
+	      ref = DF_REF_NEXT_REG (ref);
+	      gcc_checking_assert (offset < ref_info->refs_size);
+	    }
+	}
+      ref_info->count[regno] = count;
+    }
+
+  /* The bitmap size is not decremented when refs are deleted.  So
+     reset it now that we have squished out all of the empty
+     slots.  */
+  ref_info->table_size = offset;
+}
+
+
+/* Take build ref table for either the uses or defs from the reg-use
+   or reg-def chains.  This version processes the refs in insn order
+   which is likely to be best if processing some segment of the
+   function.  */
+
+static void
+df_reorganize_refs_by_reg_by_insn (struct df_ref_info *ref_info,
+				   bool include_defs,
+				   bool include_uses,
+				   bool include_eq_uses)
+{
+  bitmap_iterator bi;
+  unsigned int bb_index;
+  unsigned int m = df->regs_inited;
+  unsigned int offset = 0;
+  unsigned int r;
+  unsigned int start
+    = (df->changeable_flags & DF_NO_HARD_REGS) ? FIRST_PSEUDO_REGISTER : 0;
+
+  memset (ref_info->begin, 0, sizeof (int) * df->regs_inited);
+  memset (ref_info->count, 0, sizeof (int) * df->regs_inited);
+
+  ref_info->total_size = df_count_refs (include_defs, include_uses, include_eq_uses);
+  df_check_and_grow_ref_info (ref_info, 1);
+
+  EXECUTE_IF_SET_IN_BITMAP (df->blocks_to_analyze, 0, bb_index, bi)
+    {
+      basic_block bb = BASIC_BLOCK_FOR_FN (cfun, bb_index);
+      rtx insn;
+      df_ref *ref_rec;
+
+      if (include_defs)
+	for (ref_rec = df_get_artificial_defs (bb_index); *ref_rec; ref_rec++)
+	  {
+	    unsigned int regno = DF_REF_REGNO (*ref_rec);
+	    ref_info->count[regno]++;
+	  }
+      if (include_uses)
+	for (ref_rec = df_get_artificial_uses (bb_index); *ref_rec; ref_rec++)
+	  {
+	    unsigned int regno = DF_REF_REGNO (*ref_rec);
+	    ref_info->count[regno]++;
+	  }
+
+      FOR_BB_INSNS (bb, insn)
+	{
+	  if (INSN_P (insn))
+	    {
+	      unsigned int uid = INSN_UID (insn);
+
+	      if (include_defs)
+		for (ref_rec = DF_INSN_UID_DEFS (uid); *ref_rec; ref_rec++)
+		  {
+		    unsigned int regno = DF_REF_REGNO (*ref_rec);
+		    ref_info->count[regno]++;
+		  }
+	      if (include_uses)
+		for (ref_rec = DF_INSN_UID_USES (uid); *ref_rec; ref_rec++)
+		  {
+		    unsigned int regno = DF_REF_REGNO (*ref_rec);
+		    ref_info->count[regno]++;
+		  }
+	      if (include_eq_uses)
+		for (ref_rec = DF_INSN_UID_EQ_USES (uid); *ref_rec; ref_rec++)
+		  {
+		    unsigned int regno = DF_REF_REGNO (*ref_rec);
+		    ref_info->count[regno]++;
+		  }
+	    }
+	}
+    }
+
+  for (r = start; r < m; r++)
+    {
+      ref_info->begin[r] = offset;
+      offset += ref_info->count[r];
+      ref_info->count[r] = 0;
+    }
+
+  EXECUTE_IF_SET_IN_BITMAP (df->blocks_to_analyze, 0, bb_index, bi)
+    {
+      basic_block bb = BASIC_BLOCK_FOR_FN (cfun, bb_index);
+      rtx insn;
+      df_ref *ref_rec;
+
+      if (include_defs)
+	for (ref_rec = df_get_artificial_defs (bb_index); *ref_rec; ref_rec++)
+	  {
+	    df_ref ref = *ref_rec;
+	    unsigned int regno = DF_REF_REGNO (ref);
+	    if (regno >= start)
+	      {
+		unsigned int id
+		  = ref_info->begin[regno] + ref_info->count[regno]++;
+		DF_REF_ID (ref) = id;
+		ref_info->refs[id] = ref;
+	      }
+	  }
+      if (include_uses)
+	for (ref_rec = df_get_artificial_uses (bb_index); *ref_rec; ref_rec++)
+	  {
+	    df_ref ref = *ref_rec;
+	    unsigned int regno = DF_REF_REGNO (ref);
+	    if (regno >= start)
+	      {
+		unsigned int id
+		  = ref_info->begin[regno] + ref_info->count[regno]++;
+		DF_REF_ID (ref) = id;
+		ref_info->refs[id] = ref;
+	      }
+	  }
+
+      FOR_BB_INSNS (bb, insn)
+	{
+	  if (INSN_P (insn))
+	    {
+	      unsigned int uid = INSN_UID (insn);
+
+	      if (include_defs)
+		for (ref_rec = DF_INSN_UID_DEFS (uid); *ref_rec; ref_rec++)
+		  {
+		    df_ref ref = *ref_rec;
+		    unsigned int regno = DF_REF_REGNO (ref);
+		    if (regno >= start)
+		      {
+			unsigned int id
+			  = ref_info->begin[regno] + ref_info->count[regno]++;
+			DF_REF_ID (ref) = id;
+			ref_info->refs[id] = ref;
+		      }
+		  }
+	      if (include_uses)
+		for (ref_rec = DF_INSN_UID_USES (uid); *ref_rec; ref_rec++)
+		  {
+		    df_ref ref = *ref_rec;
+		    unsigned int regno = DF_REF_REGNO (ref);
+		    if (regno >= start)
+		      {
+			unsigned int id
+			  = ref_info->begin[regno] + ref_info->count[regno]++;
+			DF_REF_ID (ref) = id;
+			ref_info->refs[id] = ref;
+		      }
+		  }
+	      if (include_eq_uses)
+		for (ref_rec = DF_INSN_UID_EQ_USES (uid); *ref_rec; ref_rec++)
+		  {
+		    df_ref ref = *ref_rec;
+		    unsigned int regno = DF_REF_REGNO (ref);
+		    if (regno >= start)
+		      {
+			unsigned int id
+			  = ref_info->begin[regno] + ref_info->count[regno]++;
+			DF_REF_ID (ref) = id;
+			ref_info->refs[id] = ref;
+		      }
+		  }
+	    }
+	}
+    }
+
+  /* The bitmap size is not decremented when refs are deleted.  So
+     reset it now that we have squished out all of the empty
+     slots.  */
+
+  ref_info->table_size = offset;
+}
+
+/* Take build ref table for either the uses or defs from the reg-use
+   or reg-def chains.  */
+
+static void
+df_reorganize_refs_by_reg (struct df_ref_info *ref_info,
+			   bool include_defs,
+			   bool include_uses,
+			   bool include_eq_uses)
+{
+  if (df->analyze_subset)
+    df_reorganize_refs_by_reg_by_insn (ref_info, include_defs,
+				       include_uses, include_eq_uses);
+  else
+    df_reorganize_refs_by_reg_by_reg (ref_info, include_defs,
+				       include_uses, include_eq_uses);
+}
+
+
+/* Add the refs in REF_VEC to the table in REF_INFO starting at OFFSET.  */
+static unsigned int
+df_add_refs_to_table (unsigned int offset,
+		      struct df_ref_info *ref_info,
+		      df_ref *ref_vec)
+{
+  while (*ref_vec)
+    {
+      df_ref ref = *ref_vec;
+      if ((!(df->changeable_flags & DF_NO_HARD_REGS))
+	  || (DF_REF_REGNO (ref) >= FIRST_PSEUDO_REGISTER))
+	{
+	  ref_info->refs[offset] = ref;
+	  DF_REF_ID (*ref_vec) = offset++;
+	}
+      ref_vec++;
+    }
+  return offset;
+}
+
+
+/* Count the number of refs in all of the insns of BB. Include the
+   defs if INCLUDE_DEFS. Include the uses if INCLUDE_USES. Include the
+   eq_uses if INCLUDE_EQ_USES.  */
+
+static unsigned int
+df_reorganize_refs_by_insn_bb (basic_block bb, unsigned int offset,
+			       struct df_ref_info *ref_info,
+			       bool include_defs, bool include_uses,
+			       bool include_eq_uses)
+{
+  rtx insn;
+
+  if (include_defs)
+    offset = df_add_refs_to_table (offset, ref_info,
+				   df_get_artificial_defs (bb->index));
+  if (include_uses)
+    offset = df_add_refs_to_table (offset, ref_info,
+				   df_get_artificial_uses (bb->index));
+
+  FOR_BB_INSNS (bb, insn)
+    if (INSN_P (insn))
+      {
+	unsigned int uid = INSN_UID (insn);
+	if (include_defs)
+	  offset = df_add_refs_to_table (offset, ref_info,
+					 DF_INSN_UID_DEFS (uid));
+	if (include_uses)
+	  offset = df_add_refs_to_table (offset, ref_info,
+					 DF_INSN_UID_USES (uid));
+	if (include_eq_uses)
+	  offset = df_add_refs_to_table (offset, ref_info,
+					 DF_INSN_UID_EQ_USES (uid));
+      }
+  return offset;
+}
+
+
+/* Organize the refs by insn into the table in REF_INFO.  If
+   blocks_to_analyze is defined, use that set, otherwise the entire
+   program.  Include the defs if INCLUDE_DEFS. Include the uses if
+   INCLUDE_USES. Include the eq_uses if INCLUDE_EQ_USES.  */
+
+static void
+df_reorganize_refs_by_insn (struct df_ref_info *ref_info,
+			    bool include_defs, bool include_uses,
+			    bool include_eq_uses)
+{
+  basic_block bb;
+  unsigned int offset = 0;
+
+  ref_info->total_size = df_count_refs (include_defs, include_uses, include_eq_uses);
+  df_check_and_grow_ref_info (ref_info, 1);
+  if (df->blocks_to_analyze)
+    {
+      bitmap_iterator bi;
+      unsigned int index;
+
+      EXECUTE_IF_SET_IN_BITMAP (df->blocks_to_analyze, 0, index, bi)
+	{
+	  offset = df_reorganize_refs_by_insn_bb (BASIC_BLOCK_FOR_FN (cfun,
+								      index),
+						  offset, ref_info,
+						  include_defs, include_uses,
+						  include_eq_uses);
+	}
+
+      ref_info->table_size = offset;
+    }
+  else
+    {
+      FOR_ALL_BB_FN (bb, cfun)
+	offset = df_reorganize_refs_by_insn_bb (bb, offset, ref_info,
+						include_defs, include_uses,
+						include_eq_uses);
+      ref_info->table_size = offset;
+    }
+}
+
+
+/* If the use refs in DF are not organized, reorganize them.  */
+
+void
+df_maybe_reorganize_use_refs (enum df_ref_order order)
+{
+  if (order == df->use_info.ref_order)
+    return;
+
+  switch (order)
+    {
+    case DF_REF_ORDER_BY_REG:
+      df_reorganize_refs_by_reg (&df->use_info, false, true, false);
+      break;
+
+    case DF_REF_ORDER_BY_REG_WITH_NOTES:
+      df_reorganize_refs_by_reg (&df->use_info, false, true, true);
+      break;
+
+    case DF_REF_ORDER_BY_INSN:
+      df_reorganize_refs_by_insn (&df->use_info, false, true, false);
+      break;
+
+    case DF_REF_ORDER_BY_INSN_WITH_NOTES:
+      df_reorganize_refs_by_insn (&df->use_info, false, true, true);
+      break;
+
+    case DF_REF_ORDER_NO_TABLE:
+      free (df->use_info.refs);
+      df->use_info.refs = NULL;
+      df->use_info.refs_size = 0;
+      break;
+
+    case DF_REF_ORDER_UNORDERED:
+    case DF_REF_ORDER_UNORDERED_WITH_NOTES:
+      gcc_unreachable ();
+      break;
+    }
+
+  df->use_info.ref_order = order;
+}
+
+
+/* If the def refs in DF are not organized, reorganize them.  */
+
+void
+df_maybe_reorganize_def_refs (enum df_ref_order order)
+{
+  if (order == df->def_info.ref_order)
+    return;
+
+  switch (order)
+    {
+    case DF_REF_ORDER_BY_REG:
+      df_reorganize_refs_by_reg (&df->def_info, true, false, false);
+      break;
+
+    case DF_REF_ORDER_BY_INSN:
+      df_reorganize_refs_by_insn (&df->def_info, true, false, false);
+      break;
+
+    case DF_REF_ORDER_NO_TABLE:
+      free (df->def_info.refs);
+      df->def_info.refs = NULL;
+      df->def_info.refs_size = 0;
+      break;
+
+    case DF_REF_ORDER_BY_INSN_WITH_NOTES:
+    case DF_REF_ORDER_BY_REG_WITH_NOTES:
+    case DF_REF_ORDER_UNORDERED:
+    case DF_REF_ORDER_UNORDERED_WITH_NOTES:
+      gcc_unreachable ();
+      break;
+    }
+
+  df->def_info.ref_order = order;
+}
+
+
+/* Change all of the basic block references in INSN to use the insn's
+   current basic block.  This function is called from routines that move
+   instructions from one block to another.  */
+
+void
+df_insn_change_bb (rtx insn, basic_block new_bb)
+{
+  basic_block old_bb = BLOCK_FOR_INSN (insn);
+  struct df_insn_info *insn_info;
+  unsigned int uid = INSN_UID (insn);
+
+  if (old_bb == new_bb)
+    return;
+
+  set_block_for_insn (insn, new_bb);
+
+  if (!df)
+    return;
+
+  if (dump_file)
+    fprintf (dump_file, "changing bb of uid %d\n", uid);
+
+  insn_info = DF_INSN_UID_SAFE_GET (uid);
+  if (insn_info == NULL)
+    {
+      if (dump_file)
+	fprintf (dump_file, "  unscanned insn\n");
+      df_insn_rescan (insn);
+      return;
+    }
+
+  if (!INSN_P (insn))
+    return;
+
+  df_set_bb_dirty (new_bb);
+  if (old_bb)
+    {
+      if (dump_file)
+	fprintf (dump_file, "  from %d to %d\n",
+		 old_bb->index, new_bb->index);
+      df_set_bb_dirty (old_bb);
+    }
+  else
+    if (dump_file)
+      fprintf (dump_file, "  to %d\n", new_bb->index);
+}
+
+
+/* Helper function for df_ref_change_reg_with_loc.  */
+
+static void
+df_ref_change_reg_with_loc_1 (struct df_reg_info *old_df,
+			      struct df_reg_info *new_df,
+			      int new_regno, rtx loc)
+{
+  df_ref the_ref = old_df->reg_chain;
+
+  while (the_ref)
+    {
+      if ((!DF_REF_IS_ARTIFICIAL (the_ref))
+	  && DF_REF_LOC (the_ref)
+	  && (*DF_REF_LOC (the_ref) == loc))
+	{
+	  df_ref next_ref = DF_REF_NEXT_REG (the_ref);
+	  df_ref prev_ref = DF_REF_PREV_REG (the_ref);
+	  df_ref *ref_vec, *ref_vec_t;
+	  struct df_insn_info *insn_info = DF_REF_INSN_INFO (the_ref);
+	  unsigned int count = 0;
+
+	  DF_REF_REGNO (the_ref) = new_regno;
+	  DF_REF_REG (the_ref) = regno_reg_rtx[new_regno];
+
+	  /* Pull the_ref out of the old regno chain.  */
+	  if (prev_ref)
+	    DF_REF_NEXT_REG (prev_ref) = next_ref;
+	  else
+	    old_df->reg_chain = next_ref;
+	  if (next_ref)
+	    DF_REF_PREV_REG (next_ref) = prev_ref;
+	  old_df->n_refs--;
+
+	  /* Put the ref into the new regno chain.  */
+	  DF_REF_PREV_REG (the_ref) = NULL;
+	  DF_REF_NEXT_REG (the_ref) = new_df->reg_chain;
+	  if (new_df->reg_chain)
+	    DF_REF_PREV_REG (new_df->reg_chain) = the_ref;
+	  new_df->reg_chain = the_ref;
+	  new_df->n_refs++;
+	  if (DF_REF_BB (the_ref))
+	    df_set_bb_dirty (DF_REF_BB (the_ref));
+
+	  /* Need to sort the record again that the ref was in because
+	     the regno is a sorting key.  First, find the right
+	     record.  */
+	  if (DF_REF_FLAGS (the_ref) & DF_REF_IN_NOTE)
+	    ref_vec = insn_info->eq_uses;
+	  else
+	    ref_vec = insn_info->uses;
+	  if (dump_file)
+	    fprintf (dump_file, "changing reg in insn %d\n",
+		     DF_REF_INSN_UID (the_ref));
+
+	  ref_vec_t = ref_vec;
+
+	  /* Find the length.  */
+	  while (*ref_vec_t)
+	    {
+	      count++;
+	      ref_vec_t++;
+	    }
+	  qsort (ref_vec, count, sizeof (df_ref ), df_ref_compare);
+
+	  the_ref = next_ref;
+	}
+      else
+	the_ref = DF_REF_NEXT_REG (the_ref);
+    }
+}
+
+
+/* Change the regno of all refs that contained LOC from OLD_REGNO to
+   NEW_REGNO.  Refs that do not match LOC are not changed which means
+   that artificial refs are not changed since they have no loc.  This
+   call is to support the SET_REGNO macro. */
+
+void
+df_ref_change_reg_with_loc (int old_regno, int new_regno, rtx loc)
+{
+  if ((!df) || (old_regno == -1) || (old_regno == new_regno))
+    return;
+
+  df_grow_reg_info ();
+
+  df_ref_change_reg_with_loc_1 (DF_REG_DEF_GET (old_regno),
+				DF_REG_DEF_GET (new_regno), new_regno, loc);
+  df_ref_change_reg_with_loc_1 (DF_REG_USE_GET (old_regno),
+				DF_REG_USE_GET (new_regno), new_regno, loc);
+  df_ref_change_reg_with_loc_1 (DF_REG_EQ_USE_GET (old_regno),
+				DF_REG_EQ_USE_GET (new_regno), new_regno, loc);
+}
+
+
+/* Delete the mw_hardregs that point into the eq_notes.  */
+
+static unsigned int
+df_mw_hardreg_chain_delete_eq_uses (struct df_insn_info *insn_info)
+{
+  struct df_mw_hardreg **mw_vec = insn_info->mw_hardregs;
+  unsigned int deleted = 0;
+  unsigned int count = 0;
+  struct df_scan_problem_data *problem_data
+    = (struct df_scan_problem_data *) df_scan->problem_data;
+
+  if (!*mw_vec)
+    return 0;
+
+  while (*mw_vec)
+    {
+      if ((*mw_vec)->flags & DF_REF_IN_NOTE)
+	{
+	  struct df_mw_hardreg **temp_vec = mw_vec;
+
+	  pool_free (problem_data->mw_reg_pool, *mw_vec);
+	  temp_vec = mw_vec;
+	  /* Shove the remaining ones down one to fill the gap.  While
+	     this looks n**2, it is highly unusual to have any mw regs
+	     in eq_notes and the chances of more than one are almost
+	     non existent.  */
+	  while (*temp_vec)
+	    {
+	      *temp_vec = *(temp_vec + 1);
+	      temp_vec++;
+	    }
+	  deleted++;
+	}
+      else
+	{
+	  mw_vec++;
+	  count++;
+	}
+    }
+
+  if (count == 0)
+    {
+      df_scan_free_mws_vec (insn_info->mw_hardregs);
+      insn_info->mw_hardregs = df_null_mw_rec;
+      return 0;
+    }
+  return deleted;
+}
+
+
+/* Rescan only the REG_EQUIV/REG_EQUAL notes part of INSN.  */
+
+void
+df_notes_rescan (rtx insn)
+{
+  struct df_insn_info *insn_info;
+  unsigned int uid = INSN_UID (insn);
+
+  if (!df)
+    return;
+
+  /* The client has disabled rescanning and plans to do it itself.  */
+  if (df->changeable_flags & DF_NO_INSN_RESCAN)
+    return;
+
+  /* Do nothing if the insn hasn't been emitted yet.  */
+  if (!BLOCK_FOR_INSN (insn))
+    return;
+
+  df_grow_bb_info (df_scan);
+  df_grow_reg_info ();
+
+  insn_info = DF_INSN_UID_SAFE_GET (INSN_UID (insn));
+
+  /* The client has deferred rescanning.  */
+  if (df->changeable_flags & DF_DEFER_INSN_RESCAN)
+    {
+      if (!insn_info)
+	{
+	  insn_info = df_insn_create_insn_record (insn);
+	  insn_info->defs = df_null_ref_rec;
+	  insn_info->uses = df_null_ref_rec;
+	  insn_info->eq_uses = df_null_ref_rec;
+	  insn_info->mw_hardregs = df_null_mw_rec;
+	}
+
+      bitmap_clear_bit (&df->insns_to_delete, uid);
+      /* If the insn is set to be rescanned, it does not need to also
+	 be notes rescanned.  */
+      if (!bitmap_bit_p (&df->insns_to_rescan, uid))
+	bitmap_set_bit (&df->insns_to_notes_rescan, INSN_UID (insn));
+      return;
+    }
+
+  bitmap_clear_bit (&df->insns_to_delete, uid);
+  bitmap_clear_bit (&df->insns_to_notes_rescan, uid);
+
+  if (insn_info)
+    {
+      basic_block bb = BLOCK_FOR_INSN (insn);
+      rtx note;
+      struct df_collection_rec collection_rec;
+      unsigned int num_deleted;
+      unsigned int mw_len;
+
+      num_deleted = df_mw_hardreg_chain_delete_eq_uses (insn_info);
+      df_ref_chain_delete (insn_info->eq_uses);
+      insn_info->eq_uses = NULL;
+
+      /* Process REG_EQUIV/REG_EQUAL notes */
+      for (note = REG_NOTES (insn); note;
+	   note = XEXP (note, 1))
+	{
+	  switch (REG_NOTE_KIND (note))
+	    {
+	    case REG_EQUIV:
+	    case REG_EQUAL:
+	      df_uses_record (&collection_rec,
+			      &XEXP (note, 0), DF_REF_REG_USE,
+			      bb, insn_info, DF_REF_IN_NOTE);
+	    default:
+	      break;
+	    }
+	}
+
+      /* Find some place to put any new mw_hardregs.  */
+      df_canonize_collection_rec (&collection_rec);
+      mw_len = collection_rec.mw_vec.length ();
+      if (mw_len)
+	{
+	  unsigned int count = 0;
+	  struct df_mw_hardreg **mw_rec = insn_info->mw_hardregs;
+	  while (*mw_rec)
+	    {
+	      count++;
+	      mw_rec++;
+	    }
+
+	  if (count)
+	    {
+	      /* Append to the end of the existing record after
+		 expanding it if necessary.  */
+	      if (mw_len > num_deleted)
+		{
+		  insn_info->mw_hardregs =
+		    XRESIZEVEC (struct df_mw_hardreg *,
+				insn_info->mw_hardregs,
+				count + 1 + mw_len);
+		}
+	      memcpy (&insn_info->mw_hardregs[count],
+		      collection_rec.mw_vec.address (),
+		      mw_len * sizeof (struct df_mw_hardreg *));
+	      insn_info->mw_hardregs[count + mw_len] = NULL;
+	      qsort (insn_info->mw_hardregs, count + mw_len,
+		     sizeof (struct df_mw_hardreg *), df_mw_compare);
+	    }
+	  else
+	    {
+	      /* No vector there. */
+	      insn_info->mw_hardregs
+		= XNEWVEC (struct df_mw_hardreg*, 1 + mw_len);
+	      memcpy (insn_info->mw_hardregs,
+		      collection_rec.mw_vec.address (),
+		      mw_len * sizeof (struct df_mw_hardreg *));
+	      insn_info->mw_hardregs[mw_len] = NULL;
+	    }
+	}
+      df_refs_add_to_chains (&collection_rec, bb, insn, copy_eq_uses);
+    }
+  else
+    df_insn_rescan (insn);
+
+}
+
+
+/*----------------------------------------------------------------------------
+   Hard core instruction scanning code.  No external interfaces here,
+   just a lot of routines that look inside insns.
+----------------------------------------------------------------------------*/
+
+
+/* Return true if the contents of two df_ref's are identical.
+   It ignores DF_REF_MARKER.  */
+
+static bool
+df_ref_equal_p (df_ref ref1, df_ref ref2)
+{
+  if (!ref2)
+    return false;
+
+  if (ref1 == ref2)
+    return true;
+
+  if (DF_REF_CLASS (ref1) != DF_REF_CLASS (ref2)
+      || DF_REF_REGNO (ref1) != DF_REF_REGNO (ref2)
+      || DF_REF_REG (ref1) != DF_REF_REG (ref2)
+      || DF_REF_TYPE (ref1) != DF_REF_TYPE (ref2)
+      || ((DF_REF_FLAGS (ref1) & ~(DF_REF_REG_MARKER + DF_REF_MW_HARDREG))
+	  != (DF_REF_FLAGS (ref2) & ~(DF_REF_REG_MARKER + DF_REF_MW_HARDREG)))
+      || DF_REF_BB (ref1) != DF_REF_BB (ref2)
+      || DF_REF_INSN_INFO (ref1) != DF_REF_INSN_INFO (ref2))
+    return false;
+
+  switch (DF_REF_CLASS (ref1))
+    {
+    case DF_REF_ARTIFICIAL:
+    case DF_REF_BASE:
+      return true;
+
+    case DF_REF_REGULAR:
+      return DF_REF_LOC (ref1) == DF_REF_LOC (ref2);
+
+    default:
+      gcc_unreachable ();
+    }
+  return false;
+}
+
+
+/* Compare REF1 and REF2 for sorting.  This is only called from places
+   where all of the refs are of the same type, in the same insn, and
+   have the same bb.  So these fields are not checked.  */
+
+static int
+df_ref_compare (const void *r1, const void *r2)
+{
+  const df_ref ref1 = *(const df_ref *)r1;
+  const df_ref ref2 = *(const df_ref *)r2;
+
+  if (ref1 == ref2)
+    return 0;
+
+  if (DF_REF_CLASS (ref1) != DF_REF_CLASS (ref2))
+    return (int)DF_REF_CLASS (ref1) - (int)DF_REF_CLASS (ref2);
+
+  if (DF_REF_REGNO (ref1) != DF_REF_REGNO (ref2))
+    return (int)DF_REF_REGNO (ref1) - (int)DF_REF_REGNO (ref2);
+
+  if (DF_REF_TYPE (ref1) != DF_REF_TYPE (ref2))
+    return (int)DF_REF_TYPE (ref1) - (int)DF_REF_TYPE (ref2);
+
+  if (DF_REF_REG (ref1) != DF_REF_REG (ref2))
+    return (int)DF_REF_ORDER (ref1) - (int)DF_REF_ORDER (ref2);
+
+  /* Cannot look at the LOC field on artificial refs.  */
+  if (DF_REF_CLASS (ref1) != DF_REF_ARTIFICIAL
+      && DF_REF_LOC (ref1) != DF_REF_LOC (ref2))
+    return (int)DF_REF_ORDER (ref1) - (int)DF_REF_ORDER (ref2);
+
+  if (DF_REF_FLAGS (ref1) != DF_REF_FLAGS (ref2))
+    {
+      /* If two refs are identical except that one of them has is from
+	 a mw and one is not, we need to have the one with the mw
+	 first.  */
+      if (DF_REF_FLAGS_IS_SET (ref1, DF_REF_MW_HARDREG) ==
+	  DF_REF_FLAGS_IS_SET (ref2, DF_REF_MW_HARDREG))
+	return DF_REF_FLAGS (ref1) - DF_REF_FLAGS (ref2);
+      else if (DF_REF_FLAGS_IS_SET (ref1, DF_REF_MW_HARDREG))
+	return -1;
+      else
+	return 1;
+    }
+
+  return (int)DF_REF_ORDER (ref1) - (int)DF_REF_ORDER (ref2);
+}
+
+static void
+df_swap_refs (vec<df_ref, va_heap> *ref_vec, int i, int j)
+{
+  df_ref tmp = (*ref_vec)[i];
+  (*ref_vec)[i] = (*ref_vec)[j];
+  (*ref_vec)[j] = tmp;
+}
+
+/* Sort and compress a set of refs.  */
+
+static void
+df_sort_and_compress_refs (vec<df_ref, va_heap> *ref_vec)
+{
+  unsigned int count;
+  unsigned int i;
+  unsigned int dist = 0;
+
+  count = ref_vec->length ();
+
+  /* If there are 1 or 0 elements, there is nothing to do.  */
+  if (count < 2)
+    return;
+  else if (count == 2)
+    {
+      df_ref r0 = (*ref_vec)[0];
+      df_ref r1 = (*ref_vec)[1];
+      if (df_ref_compare (&r0, &r1) > 0)
+        df_swap_refs (ref_vec, 0, 1);
+    }
+  else
+    {
+      for (i = 0; i < count - 1; i++)
+	{
+	  df_ref r0 = (*ref_vec)[i];
+	  df_ref r1 = (*ref_vec)[i + 1];
+	  if (df_ref_compare (&r0, &r1) >= 0)
+	    break;
+	}
+      /* If the array is already strictly ordered,
+         which is the most common case for large COUNT case
+         (which happens for CALL INSNs),
+         no need to sort and filter out duplicate.
+         Simply return the count.
+         Make sure DF_GET_ADD_REFS adds refs in the increasing order
+         of DF_REF_COMPARE.  */
+      if (i == count - 1)
+        return;
+      ref_vec->qsort (df_ref_compare);
+    }
+
+  for (i=0; i<count-dist; i++)
+    {
+      /* Find the next ref that is not equal to the current ref.  */
+      while (i + dist + 1 < count
+	     && df_ref_equal_p ((*ref_vec)[i],
+				(*ref_vec)[i + dist + 1]))
+	{
+	  df_free_ref ((*ref_vec)[i + dist + 1]);
+	  dist++;
+	}
+      /* Copy it down to the next position.  */
+      if (dist && i + dist + 1 < count)
+	(*ref_vec)[i + 1] = (*ref_vec)[i + dist + 1];
+    }
+
+  count -= dist;
+  ref_vec->truncate (count);
+}
+
+
+/* Return true if the contents of two df_ref's are identical.
+   It ignores DF_REF_MARKER.  */
+
+static bool
+df_mw_equal_p (struct df_mw_hardreg *mw1, struct df_mw_hardreg *mw2)
+{
+  if (!mw2)
+    return false;
+  return (mw1 == mw2) ||
+    (mw1->mw_reg == mw2->mw_reg
+     && mw1->type == mw2->type
+     && mw1->flags == mw2->flags
+     && mw1->start_regno == mw2->start_regno
+     && mw1->end_regno == mw2->end_regno);
+}
+
+
+/* Compare MW1 and MW2 for sorting.  */
+
+static int
+df_mw_compare (const void *m1, const void *m2)
+{
+  const struct df_mw_hardreg *const mw1 = *(const struct df_mw_hardreg *const*)m1;
+  const struct df_mw_hardreg *const mw2 = *(const struct df_mw_hardreg *const*)m2;
+
+  if (mw1 == mw2)
+    return 0;
+
+  if (mw1->type != mw2->type)
+    return mw1->type - mw2->type;
+
+  if (mw1->flags != mw2->flags)
+    return mw1->flags - mw2->flags;
+
+  if (mw1->start_regno != mw2->start_regno)
+    return mw1->start_regno - mw2->start_regno;
+
+  if (mw1->end_regno != mw2->end_regno)
+    return mw1->end_regno - mw2->end_regno;
+
+  if (mw1->mw_reg != mw2->mw_reg)
+    return mw1->mw_order - mw2->mw_order;
+
+  return 0;
+}
+
+
+/* Sort and compress a set of refs.  */
+
+static void
+df_sort_and_compress_mws (vec<df_mw_hardreg_ptr, va_heap> *mw_vec)
+{
+  unsigned int count;
+  struct df_scan_problem_data *problem_data
+    = (struct df_scan_problem_data *) df_scan->problem_data;
+  unsigned int i;
+  unsigned int dist = 0;
+
+  count = mw_vec->length ();
+  if (count < 2)
+    return;
+  else if (count == 2)
+    {
+      struct df_mw_hardreg *m0 = (*mw_vec)[0];
+      struct df_mw_hardreg *m1 = (*mw_vec)[1];
+      if (df_mw_compare (&m0, &m1) > 0)
+        {
+          struct df_mw_hardreg *tmp = (*mw_vec)[0];
+	  (*mw_vec)[0] = (*mw_vec)[1];
+	  (*mw_vec)[1] = tmp;
+        }
+    }
+  else
+    mw_vec->qsort (df_mw_compare);
+
+  for (i=0; i<count-dist; i++)
+    {
+      /* Find the next ref that is not equal to the current ref.  */
+      while (i + dist + 1 < count
+	     && df_mw_equal_p ((*mw_vec)[i], (*mw_vec)[i + dist + 1]))
+	{
+	  pool_free (problem_data->mw_reg_pool,
+		     (*mw_vec)[i + dist + 1]);
+	  dist++;
+	}
+      /* Copy it down to the next position.  */
+      if (dist && i + dist + 1 < count)
+	(*mw_vec)[i + 1] = (*mw_vec)[i + dist + 1];
+    }
+
+  count -= dist;
+  mw_vec->truncate (count);
+}
+
+
+/* Sort and remove duplicates from the COLLECTION_REC.  */
+
+static void
+df_canonize_collection_rec (struct df_collection_rec *collection_rec)
+{
+  df_sort_and_compress_refs (&collection_rec->def_vec);
+  df_sort_and_compress_refs (&collection_rec->use_vec);
+  df_sort_and_compress_refs (&collection_rec->eq_use_vec);
+  df_sort_and_compress_mws (&collection_rec->mw_vec);
+}
+
+
+/* Add the new df_ref to appropriate reg_info/ref_info chains.  */
+
+static void
+df_install_ref (df_ref this_ref,
+		struct df_reg_info *reg_info,
+		struct df_ref_info *ref_info,
+		bool add_to_table)
+{
+  unsigned int regno = DF_REF_REGNO (this_ref);
+  /* Add the ref to the reg_{def,use,eq_use} chain.  */
+  df_ref head = reg_info->reg_chain;
+
+  reg_info->reg_chain = this_ref;
+  reg_info->n_refs++;
+
+  if (DF_REF_FLAGS_IS_SET (this_ref, DF_HARD_REG_LIVE))
+    {
+      gcc_assert (regno < FIRST_PSEUDO_REGISTER);
+      df->hard_regs_live_count[regno]++;
+    }
+
+  gcc_checking_assert (DF_REF_NEXT_REG (this_ref) == NULL
+		       && DF_REF_PREV_REG (this_ref) == NULL);
+
+  DF_REF_NEXT_REG (this_ref) = head;
+
+  /* We cannot actually link to the head of the chain.  */
+  DF_REF_PREV_REG (this_ref) = NULL;
+
+  if (head)
+    DF_REF_PREV_REG (head) = this_ref;
+
+  if (add_to_table)
+    {
+      gcc_assert (ref_info->ref_order != DF_REF_ORDER_NO_TABLE);
+      df_check_and_grow_ref_info (ref_info, 1);
+      DF_REF_ID (this_ref) = ref_info->table_size;
+      /* Add the ref to the big array of defs.  */
+      ref_info->refs[ref_info->table_size] = this_ref;
+      ref_info->table_size++;
+    }
+  else
+    DF_REF_ID (this_ref) = -1;
+
+  ref_info->total_size++;
+}
+
+
+/* This function takes one of the groups of refs (defs, uses or
+   eq_uses) and installs the entire group into the insn.  It also adds
+   each of these refs into the appropriate chains.  */
+
+static df_ref *
+df_install_refs (basic_block bb,
+		 const vec<df_ref, va_heap> *old_vec,
+		 struct df_reg_info **reg_info,
+		 struct df_ref_info *ref_info,
+		 bool is_notes)
+{
+  unsigned int count = old_vec->length ();
+  if (count)
+    {
+      df_ref *new_vec = XNEWVEC (df_ref, count + 1);
+      bool add_to_table;
+      df_ref this_ref;
+      unsigned int ix;
+
+      switch (ref_info->ref_order)
+	{
+	case DF_REF_ORDER_UNORDERED_WITH_NOTES:
+	case DF_REF_ORDER_BY_REG_WITH_NOTES:
+	case DF_REF_ORDER_BY_INSN_WITH_NOTES:
+	  ref_info->ref_order = DF_REF_ORDER_UNORDERED_WITH_NOTES;
+	  add_to_table = true;
+	  break;
+	case DF_REF_ORDER_UNORDERED:
+	case DF_REF_ORDER_BY_REG:
+	case DF_REF_ORDER_BY_INSN:
+	  ref_info->ref_order = DF_REF_ORDER_UNORDERED;
+	  add_to_table = !is_notes;
+	  break;
+	default:
+	  add_to_table = false;
+	  break;
+	}
+
+      /* Do not add if ref is not in the right blocks.  */
+      if (add_to_table && df->analyze_subset)
+	add_to_table = bitmap_bit_p (df->blocks_to_analyze, bb->index);
+
+      FOR_EACH_VEC_ELT (*old_vec, ix, this_ref)
+	{
+	  new_vec[ix] = this_ref;
+	  df_install_ref (this_ref, reg_info[DF_REF_REGNO (this_ref)],
+			  ref_info, add_to_table);
+	}
+
+      new_vec[count] = NULL;
+      return new_vec;
+    }
+  else
+    return df_null_ref_rec;
+}
+
+
+/* This function takes the mws installs the entire group into the
+   insn.  */
+
+static struct df_mw_hardreg **
+df_install_mws (const vec<df_mw_hardreg_ptr, va_heap> *old_vec)
+{
+  unsigned int count = old_vec->length ();
+  if (count)
+    {
+      struct df_mw_hardreg **new_vec
+	= XNEWVEC (struct df_mw_hardreg*, count + 1);
+      memcpy (new_vec, old_vec->address (),
+	      sizeof (struct df_mw_hardreg*) * count);
+      new_vec[count] = NULL;
+      return new_vec;
+    }
+  else
+    return df_null_mw_rec;
+}
+
+
+/* Add a chain of df_refs to appropriate ref chain/reg_info/ref_info
+   chains and update other necessary information.  */
+
+static void
+df_refs_add_to_chains (struct df_collection_rec *collection_rec,
+		       basic_block bb, rtx insn, unsigned int flags)
+{
+  if (insn)
+    {
+      struct df_insn_info *insn_rec = DF_INSN_INFO_GET (insn);
+      /* If there is a vector in the collection rec, add it to the
+	 insn.  A null rec is a signal that the caller will handle the
+	 chain specially.  */
+      if (flags & copy_defs)
+	{
+	  df_scan_free_ref_vec (insn_rec->defs);
+	  insn_rec->defs
+	    = df_install_refs (bb, &collection_rec->def_vec,
+			       df->def_regs,
+			       &df->def_info, false);
+	}
+      if (flags & copy_uses)
+	{
+	  df_scan_free_ref_vec (insn_rec->uses);
+	  insn_rec->uses
+	    = df_install_refs (bb, &collection_rec->use_vec,
+			       df->use_regs,
+			       &df->use_info, false);
+	}
+      if (flags & copy_eq_uses)
+	{
+	  df_scan_free_ref_vec (insn_rec->eq_uses);
+	  insn_rec->eq_uses
+	    = df_install_refs (bb, &collection_rec->eq_use_vec,
+			       df->eq_use_regs,
+			       &df->use_info, true);
+	}
+      if (flags & copy_mw)
+	{
+	  df_scan_free_mws_vec (insn_rec->mw_hardregs);
+	  insn_rec->mw_hardregs
+	    = df_install_mws (&collection_rec->mw_vec);
+	}
+    }
+  else
+    {
+      struct df_scan_bb_info *bb_info = df_scan_get_bb_info (bb->index);
+
+      df_scan_free_ref_vec (bb_info->artificial_defs);
+      bb_info->artificial_defs
+	= df_install_refs (bb, &collection_rec->def_vec,
+			   df->def_regs,
+			   &df->def_info, false);
+      df_scan_free_ref_vec (bb_info->artificial_uses);
+      bb_info->artificial_uses
+	= df_install_refs (bb, &collection_rec->use_vec,
+			   df->use_regs,
+			   &df->use_info, false);
+    }
+}
+
+
+/* Allocate a ref and initialize its fields.  */
+
+static df_ref
+df_ref_create_structure (enum df_ref_class cl,
+			 struct df_collection_rec *collection_rec,
+			 rtx reg, rtx *loc,
+			 basic_block bb, struct df_insn_info *info,
+			 enum df_ref_type ref_type,
+			 int ref_flags)
+{
+  df_ref this_ref = NULL;
+  int regno = REGNO (GET_CODE (reg) == SUBREG ? SUBREG_REG (reg) : reg);
+  struct df_scan_problem_data *problem_data
+    = (struct df_scan_problem_data *) df_scan->problem_data;
+
+  switch (cl)
+    {
+    case DF_REF_BASE:
+      this_ref = (df_ref) pool_alloc (problem_data->ref_base_pool);
+      gcc_checking_assert (loc == NULL);
+      break;
+
+    case DF_REF_ARTIFICIAL:
+      this_ref = (df_ref) pool_alloc (problem_data->ref_artificial_pool);
+      this_ref->artificial_ref.bb = bb;
+      gcc_checking_assert (loc == NULL);
+      break;
+
+    case DF_REF_REGULAR:
+      this_ref = (df_ref) pool_alloc (problem_data->ref_regular_pool);
+      this_ref->regular_ref.loc = loc;
+      gcc_checking_assert (loc);
+      break;
+    }
+
+  DF_REF_CLASS (this_ref) = cl;
+  DF_REF_ID (this_ref) = -1;
+  DF_REF_REG (this_ref) = reg;
+  DF_REF_REGNO (this_ref) =  regno;
+  DF_REF_TYPE (this_ref) = ref_type;
+  DF_REF_INSN_INFO (this_ref) = info;
+  DF_REF_CHAIN (this_ref) = NULL;
+  DF_REF_FLAGS (this_ref) = ref_flags;
+  DF_REF_NEXT_REG (this_ref) = NULL;
+  DF_REF_PREV_REG (this_ref) = NULL;
+  DF_REF_ORDER (this_ref) = df->ref_order++;
+
+  /* We need to clear this bit because fwprop, and in the future
+     possibly other optimizations sometimes create new refs using ond
+     refs as the model.  */
+  DF_REF_FLAGS_CLEAR (this_ref, DF_HARD_REG_LIVE);
+
+  /* See if this ref needs to have DF_HARD_REG_LIVE bit set.  */
+  if (regno < FIRST_PSEUDO_REGISTER
+      && !DF_REF_IS_ARTIFICIAL (this_ref)
+      && !DEBUG_INSN_P (DF_REF_INSN (this_ref)))
+    {
+      if (DF_REF_REG_DEF_P (this_ref))
+	{
+	  if (!DF_REF_FLAGS_IS_SET (this_ref, DF_REF_MAY_CLOBBER))
+	    DF_REF_FLAGS_SET (this_ref, DF_HARD_REG_LIVE);
+	}
+      else if (!(TEST_HARD_REG_BIT (elim_reg_set, regno)
+		 && (regno == FRAME_POINTER_REGNUM
+		     || regno == ARG_POINTER_REGNUM)))
+	DF_REF_FLAGS_SET (this_ref, DF_HARD_REG_LIVE);
+    }
+
+  if (collection_rec)
+    {
+      if (DF_REF_REG_DEF_P (this_ref))
+	collection_rec->def_vec.safe_push (this_ref);
+      else if (DF_REF_FLAGS (this_ref) & DF_REF_IN_NOTE)
+	collection_rec->eq_use_vec.safe_push (this_ref);
+      else
+	collection_rec->use_vec.safe_push (this_ref);
+    }
+  else
+    df_install_ref_incremental (this_ref);
+
+  return this_ref;
+}
+
+
+/* Create new references of type DF_REF_TYPE for each part of register REG
+   at address LOC within INSN of BB.  */
+
+
+static void
+df_ref_record (enum df_ref_class cl,
+	       struct df_collection_rec *collection_rec,
+               rtx reg, rtx *loc,
+	       basic_block bb, struct df_insn_info *insn_info,
+	       enum df_ref_type ref_type,
+	       int ref_flags)
+{
+  unsigned int regno;
+
+  gcc_checking_assert (REG_P (reg) || GET_CODE (reg) == SUBREG);
+
+  regno = REGNO (GET_CODE (reg) == SUBREG ? SUBREG_REG (reg) : reg);
+  if (regno < FIRST_PSEUDO_REGISTER)
+    {
+      struct df_mw_hardreg *hardreg = NULL;
+      struct df_scan_problem_data *problem_data
+        = (struct df_scan_problem_data *) df_scan->problem_data;
+      unsigned int i;
+      unsigned int endregno;
+      df_ref ref;
+
+      if (GET_CODE (reg) == SUBREG)
+	{
+	  regno += subreg_regno_offset (regno, GET_MODE (SUBREG_REG (reg)),
+					SUBREG_BYTE (reg), GET_MODE (reg));
+	  endregno = regno + subreg_nregs (reg);
+	}
+      else
+	endregno = END_HARD_REGNO (reg);
+
+      /*  If this is a multiword hardreg, we create some extra
+	  datastructures that will enable us to easily build REG_DEAD
+	  and REG_UNUSED notes.  */
+      if (collection_rec
+	  && (endregno != regno + 1) && insn_info)
+	{
+	  /* Sets to a subreg of a multiword register are partial.
+	     Sets to a non-subreg of a multiword register are not.  */
+	  if (GET_CODE (reg) == SUBREG)
+	    ref_flags |= DF_REF_PARTIAL;
+	  ref_flags |= DF_REF_MW_HARDREG;
+
+	  hardreg = (struct df_mw_hardreg *) pool_alloc (problem_data->mw_reg_pool);
+	  hardreg->type = ref_type;
+	  hardreg->flags = ref_flags;
+	  hardreg->mw_reg = reg;
+	  hardreg->start_regno = regno;
+	  hardreg->end_regno = endregno - 1;
+	  hardreg->mw_order = df->ref_order++;
+	  collection_rec->mw_vec.safe_push (hardreg);
+	}
+
+      for (i = regno; i < endregno; i++)
+	{
+	  ref = df_ref_create_structure (cl, collection_rec, regno_reg_rtx[i], loc,
+					 bb, insn_info, ref_type, ref_flags);
+
+          gcc_assert (ORIGINAL_REGNO (DF_REF_REG (ref)) == i);
+	}
+    }
+  else
+    {
+      df_ref_create_structure (cl, collection_rec, reg, loc, bb, insn_info,
+			       ref_type, ref_flags);
+    }
+}
+
+
+/* A set to a non-paradoxical SUBREG for which the number of word_mode units
+   covered by the outer mode is smaller than that covered by the inner mode,
+   is a read-modify-write operation.
+   This function returns true iff the SUBREG X is such a SUBREG.  */
+
+bool
+df_read_modify_subreg_p (rtx x)
+{
+  unsigned int isize, osize;
+  if (GET_CODE (x) != SUBREG)
+    return false;
+  isize = GET_MODE_SIZE (GET_MODE (SUBREG_REG (x)));
+  osize = GET_MODE_SIZE (GET_MODE (x));
+  return isize > osize
+	 && isize > REGMODE_NATURAL_SIZE (GET_MODE (SUBREG_REG (x)));
+}
+
+
+/* Process all the registers defined in the rtx pointed by LOC.
+   Autoincrement/decrement definitions will be picked up by df_uses_record.
+   Any change here has to be matched in df_find_hard_reg_defs_1.  */
+
+static void
+df_def_record_1 (struct df_collection_rec *collection_rec,
+                 rtx *loc, basic_block bb, struct df_insn_info *insn_info,
+		 int flags)
+{
+  rtx dst = *loc;
+
+  /* It is legal to have a set destination be a parallel. */
+  if (GET_CODE (dst) == PARALLEL)
+    {
+      int i;
+      for (i = XVECLEN (dst, 0) - 1; i >= 0; i--)
+	{
+	  rtx temp = XVECEXP (dst, 0, i);
+	  gcc_assert (GET_CODE (temp) == EXPR_LIST);
+	  df_def_record_1 (collection_rec, &XEXP (temp, 0),
+			   bb, insn_info, flags);
+	}
+      return;
+    }
+
+  if (GET_CODE (dst) == STRICT_LOW_PART)
+    {
+      flags |= DF_REF_READ_WRITE | DF_REF_PARTIAL | DF_REF_STRICT_LOW_PART;
+
+      loc = &XEXP (dst, 0);
+      dst = *loc;
+    }
+
+  if (GET_CODE (dst) == ZERO_EXTRACT)
+    {
+      flags |= DF_REF_READ_WRITE | DF_REF_PARTIAL | DF_REF_ZERO_EXTRACT;
+
+      loc = &XEXP (dst, 0);
+      dst = *loc;
+    }
+
+  /* At this point if we do not have a reg or a subreg, just return.  */
+  if (REG_P (dst))
+    {
+      df_ref_record (DF_REF_REGULAR, collection_rec,
+		     dst, loc, bb, insn_info, DF_REF_REG_DEF, flags);
+
+      /* We want to keep sp alive everywhere - by making all
+	 writes to sp also use of sp. */
+      if (REGNO (dst) == STACK_POINTER_REGNUM)
+	df_ref_record (DF_REF_BASE, collection_rec,
+		       dst, NULL, bb, insn_info, DF_REF_REG_USE, flags);
+    }
+  else if (GET_CODE (dst) == SUBREG && REG_P (SUBREG_REG (dst)))
+    {
+      if (df_read_modify_subreg_p (dst))
+	flags |= DF_REF_READ_WRITE | DF_REF_PARTIAL;
+
+      flags |= DF_REF_SUBREG;
+
+      df_ref_record (DF_REF_REGULAR, collection_rec,
+		     dst, loc, bb, insn_info, DF_REF_REG_DEF, flags);
+    }
+}
+
+
+/* Process all the registers defined in the pattern rtx, X.  Any change
+   here has to be matched in df_find_hard_reg_defs.  */
+
+static void
+df_defs_record (struct df_collection_rec *collection_rec,
+                rtx x, basic_block bb, struct df_insn_info *insn_info,
+		int flags)
+{
+  RTX_CODE code = GET_CODE (x);
+  int i;
+
+  switch (code)
+    {
+    case SET:
+      df_def_record_1 (collection_rec, &SET_DEST (x), bb, insn_info, flags);
+      break;
+
+    case CLOBBER:
+      flags |= DF_REF_MUST_CLOBBER;
+      df_def_record_1 (collection_rec, &XEXP (x, 0), bb, insn_info, flags);
+      break;
+
+    case COND_EXEC:
+      df_defs_record (collection_rec, COND_EXEC_CODE (x),
+		      bb, insn_info, DF_REF_CONDITIONAL);
+      break;
+
+    case PARALLEL:
+      for (i = 0; i < XVECLEN (x, 0); i++)
+	df_defs_record (collection_rec, XVECEXP (x, 0, i),
+			bb, insn_info, flags);
+      break;
+    default:
+      /* No DEFs to record in other cases */
+      break;
+    }
+}
+
+/* Set bits in *DEFS for hard registers found in the rtx DST, which is the
+   destination of a set or clobber.  This has to match the logic in
+   df_defs_record_1.  */
+
+static void
+df_find_hard_reg_defs_1 (rtx dst, HARD_REG_SET *defs)
+{
+  /* It is legal to have a set destination be a parallel. */
+  if (GET_CODE (dst) == PARALLEL)
+    {
+      int i;
+      for (i = XVECLEN (dst, 0) - 1; i >= 0; i--)
+	{
+	  rtx temp = XVECEXP (dst, 0, i);
+	  gcc_assert (GET_CODE (temp) == EXPR_LIST);
+	  df_find_hard_reg_defs_1 (XEXP (temp, 0), defs);
+	}
+      return;
+    }
+
+  if (GET_CODE (dst) == STRICT_LOW_PART)
+      dst = XEXP (dst, 0);
+
+  if (GET_CODE (dst) == ZERO_EXTRACT)
+      dst = XEXP (dst, 0);
+
+  /* At this point if we do not have a reg or a subreg, just return.  */
+  if (REG_P (dst) && HARD_REGISTER_P (dst))
+    SET_HARD_REG_BIT (*defs, REGNO (dst));
+  else if (GET_CODE (dst) == SUBREG
+	   && REG_P (SUBREG_REG (dst)) && HARD_REGISTER_P (dst))
+    SET_HARD_REG_BIT (*defs, REGNO (SUBREG_REG (dst)));
+}
+
+/* Set bits in *DEFS for hard registers defined in the pattern X.  This
+   has to match the logic in df_defs_record.  */
+
+static void
+df_find_hard_reg_defs (rtx x, HARD_REG_SET *defs)
+{
+  RTX_CODE code = GET_CODE (x);
+  int i;
+
+  switch (code)
+    {
+    case SET:
+      df_find_hard_reg_defs_1 (SET_DEST (x), defs);
+      break;
+
+    case CLOBBER:
+      df_find_hard_reg_defs_1 (XEXP (x, 0), defs);
+      break;
+
+    case COND_EXEC:
+      df_find_hard_reg_defs (COND_EXEC_CODE (x), defs);
+      break;
+
+    case PARALLEL:
+      for (i = 0; i < XVECLEN (x, 0); i++)
+	df_find_hard_reg_defs (XVECEXP (x, 0, i), defs);
+      break;
+    default:
+      /* No DEFs to record in other cases */
+      break;
+    }
+}
+
+
+/* Process all the registers used in the rtx at address LOC.  */
+
+static void
+df_uses_record (struct df_collection_rec *collection_rec,
+                rtx *loc, enum df_ref_type ref_type,
+		basic_block bb, struct df_insn_info *insn_info,
+		int flags)
+{
+  RTX_CODE code;
+  rtx x;
+
+ retry:
+  x = *loc;
+  if (!x)
+    return;
+  code = GET_CODE (x);
+  switch (code)
+    {
+    case LABEL_REF:
+    case SYMBOL_REF:
+    case CONST:
+    CASE_CONST_ANY:
+    case PC:
+    case CC0:
+    case ADDR_VEC:
+    case ADDR_DIFF_VEC:
+      return;
+
+    case CLOBBER:
+      /* If we are clobbering a MEM, mark any registers inside the address
+	 as being used.  */
+      if (MEM_P (XEXP (x, 0)))
+	df_uses_record (collection_rec,
+			&XEXP (XEXP (x, 0), 0),
+			DF_REF_REG_MEM_STORE,
+		        bb, insn_info,
+			flags);
+
+      /* If we're clobbering a REG then we have a def so ignore.  */
+      return;
+
+    case MEM:
+      df_uses_record (collection_rec,
+		      &XEXP (x, 0), DF_REF_REG_MEM_LOAD,
+		      bb, insn_info, flags & DF_REF_IN_NOTE);
+      return;
+
+    case SUBREG:
+      /* While we're here, optimize this case.  */
+      flags |= DF_REF_PARTIAL;
+      /* In case the SUBREG is not of a REG, do not optimize.  */
+      if (!REG_P (SUBREG_REG (x)))
+	{
+	  loc = &SUBREG_REG (x);
+	  df_uses_record (collection_rec, loc, ref_type, bb, insn_info, flags);
+	  return;
+	}
+      /* ... Fall through ...  */
+
+    case REG:
+      df_ref_record (DF_REF_REGULAR, collection_rec,
+		     x, loc, bb, insn_info,
+		     ref_type, flags);
+      return;
+
+    case SIGN_EXTRACT:
+    case ZERO_EXTRACT:
+      {
+        df_uses_record (collection_rec,
+                        &XEXP (x, 1), ref_type, bb, insn_info, flags);
+        df_uses_record (collection_rec,
+                        &XEXP (x, 2), ref_type, bb, insn_info, flags);
+
+        /* If the parameters to the zero or sign extract are
+           constants, strip them off and recurse, otherwise there is
+           no information that we can gain from this operation.  */
+        if (code == ZERO_EXTRACT)
+          flags |= DF_REF_ZERO_EXTRACT;
+        else
+          flags |= DF_REF_SIGN_EXTRACT;
+
+        df_uses_record (collection_rec,
+                        &XEXP (x, 0), ref_type, bb, insn_info, flags);
+        return;
+      }
+      break;
+
+    case SET:
+      {
+	rtx dst = SET_DEST (x);
+	gcc_assert (!(flags & DF_REF_IN_NOTE));
+	df_uses_record (collection_rec,
+			&SET_SRC (x), DF_REF_REG_USE, bb, insn_info, flags);
+
+	switch (GET_CODE (dst))
+	  {
+	    case SUBREG:
+	      if (df_read_modify_subreg_p (dst))
+		{
+		  df_uses_record (collection_rec, &SUBREG_REG (dst),
+				  DF_REF_REG_USE, bb, insn_info,
+				  flags | DF_REF_READ_WRITE | DF_REF_SUBREG);
+		  break;
+		}
+	      /* Fall through.  */
+	    case REG:
+	    case PARALLEL:
+	    case SCRATCH:
+	    case PC:
+	    case CC0:
+		break;
+	    case MEM:
+	      df_uses_record (collection_rec, &XEXP (dst, 0),
+			      DF_REF_REG_MEM_STORE, bb, insn_info, flags);
+	      break;
+	    case STRICT_LOW_PART:
+	      {
+		rtx *temp = &XEXP (dst, 0);
+		/* A strict_low_part uses the whole REG and not just the
+		 SUBREG.  */
+		dst = XEXP (dst, 0);
+		df_uses_record (collection_rec,
+				(GET_CODE (dst) == SUBREG) ? &SUBREG_REG (dst) : temp,
+				DF_REF_REG_USE, bb, insn_info,
+				DF_REF_READ_WRITE | DF_REF_STRICT_LOW_PART);
+	      }
+	      break;
+	    case ZERO_EXTRACT:
+	      {
+		df_uses_record (collection_rec, &XEXP (dst, 1),
+				DF_REF_REG_USE, bb, insn_info, flags);
+		df_uses_record (collection_rec, &XEXP (dst, 2),
+				DF_REF_REG_USE, bb, insn_info, flags);
+                if (GET_CODE (XEXP (dst,0)) == MEM)
+                  df_uses_record (collection_rec, &XEXP (dst, 0),
+                                  DF_REF_REG_USE, bb, insn_info,
+                                  flags);
+                else
+                  df_uses_record (collection_rec, &XEXP (dst, 0),
+                                  DF_REF_REG_USE, bb, insn_info,
+                                  DF_REF_READ_WRITE | DF_REF_ZERO_EXTRACT);
+	      }
+	      break;
+
+	    default:
+	      gcc_unreachable ();
+	  }
+	return;
+      }
+
+    case RETURN:
+    case SIMPLE_RETURN:
+      break;
+
+    case ASM_OPERANDS:
+    case UNSPEC_VOLATILE:
+    case TRAP_IF:
+    case ASM_INPUT:
+      {
+	/* Traditional and volatile asm instructions must be
+	   considered to use and clobber all hard registers, all
+	   pseudo-registers and all of memory.  So must TRAP_IF and
+	   UNSPEC_VOLATILE operations.
+
+	   Consider for instance a volatile asm that changes the fpu
+	   rounding mode.  An insn should not be moved across this
+	   even if it only uses pseudo-regs because it might give an
+	   incorrectly rounded result.
+
+	   However, flow.c's liveness computation did *not* do this,
+	   giving the reasoning as " ?!? Unfortunately, marking all
+	   hard registers as live causes massive problems for the
+	   register allocator and marking all pseudos as live creates
+	   mountains of uninitialized variable warnings."
+
+	   In order to maintain the status quo with regard to liveness
+	   and uses, we do what flow.c did and just mark any regs we
+	   can find in ASM_OPERANDS as used.  In global asm insns are
+	   scanned and regs_asm_clobbered is filled out.
+
+	   For all ASM_OPERANDS, we must traverse the vector of input
+	   operands.  We can not just fall through here since then we
+	   would be confused by the ASM_INPUT rtx inside ASM_OPERANDS,
+	   which do not indicate traditional asms unlike their normal
+	   usage.  */
+	if (code == ASM_OPERANDS)
+	  {
+	    int j;
+
+	    for (j = 0; j < ASM_OPERANDS_INPUT_LENGTH (x); j++)
+	      df_uses_record (collection_rec, &ASM_OPERANDS_INPUT (x, j),
+			      DF_REF_REG_USE, bb, insn_info, flags);
+	    return;
+	  }
+	break;
+      }
+
+    case VAR_LOCATION:
+      df_uses_record (collection_rec,
+		      &PAT_VAR_LOCATION_LOC (x),
+		      DF_REF_REG_USE, bb, insn_info, flags);
+      return;
+
+    case PRE_DEC:
+    case POST_DEC:
+    case PRE_INC:
+    case POST_INC:
+    case PRE_MODIFY:
+    case POST_MODIFY:
+      gcc_assert (!DEBUG_INSN_P (insn_info->insn));
+      /* Catch the def of the register being modified.  */
+      df_ref_record (DF_REF_REGULAR, collection_rec, XEXP (x, 0), &XEXP (x, 0),
+		     bb, insn_info,
+		     DF_REF_REG_DEF,
+                     flags | DF_REF_READ_WRITE | DF_REF_PRE_POST_MODIFY);
+
+      /* ... Fall through to handle uses ...  */
+
+    default:
+      break;
+    }
+
+  /* Recursively scan the operands of this expression.  */
+  {
+    const char *fmt = GET_RTX_FORMAT (code);
+    int i;
+
+    for (i = GET_RTX_LENGTH (code) - 1; i >= 0; i--)
+      {
+	if (fmt[i] == 'e')
+	  {
+	    /* Tail recursive case: save a function call level.  */
+	    if (i == 0)
+	      {
+		loc = &XEXP (x, 0);
+		goto retry;
+	      }
+	    df_uses_record (collection_rec, &XEXP (x, i), ref_type,
+			    bb, insn_info, flags);
+	  }
+	else if (fmt[i] == 'E')
+	  {
+	    int j;
+	    for (j = 0; j < XVECLEN (x, i); j++)
+	      df_uses_record (collection_rec,
+			      &XVECEXP (x, i, j), ref_type,
+			      bb, insn_info, flags);
+	  }
+      }
+  }
+
+  return;
+}
+
+
+/* For all DF_REF_CONDITIONAL defs, add a corresponding uses.  */
+
+static void
+df_get_conditional_uses (struct df_collection_rec *collection_rec)
+{
+  unsigned int ix;
+  df_ref ref;
+
+  FOR_EACH_VEC_ELT (collection_rec->def_vec, ix, ref)
+    {
+      if (DF_REF_FLAGS_IS_SET (ref, DF_REF_CONDITIONAL))
+        {
+          df_ref use;
+
+          use = df_ref_create_structure (DF_REF_CLASS (ref), collection_rec, DF_REF_REG (ref),
+					 DF_REF_LOC (ref), DF_REF_BB (ref),
+					 DF_REF_INSN_INFO (ref), DF_REF_REG_USE,
+					 DF_REF_FLAGS (ref) & ~DF_REF_CONDITIONAL);
+          DF_REF_REGNO (use) = DF_REF_REGNO (ref);
+        }
+    }
+}
+
+
+/* Get call's extra defs and uses (track caller-saved registers). */
+
+static void
+df_get_call_refs (struct df_collection_rec *collection_rec,
+                  basic_block bb,
+                  struct df_insn_info *insn_info,
+                  int flags)
+{
+  rtx note;
+  bool is_sibling_call;
+  unsigned int i;
+  HARD_REG_SET defs_generated;
+
+  CLEAR_HARD_REG_SET (defs_generated);
+  df_find_hard_reg_defs (PATTERN (insn_info->insn), &defs_generated);
+  is_sibling_call = SIBLING_CALL_P (insn_info->insn);
+
+  for (i = 0; i < FIRST_PSEUDO_REGISTER; i++)
+    {
+      if (i == STACK_POINTER_REGNUM)
+	/* The stack ptr is used (honorarily) by a CALL insn.  */
+	df_ref_record (DF_REF_BASE, collection_rec, regno_reg_rtx[i],
+		       NULL, bb, insn_info, DF_REF_REG_USE,
+		       DF_REF_CALL_STACK_USAGE | flags);
+      else if (global_regs[i])
+	{
+	  /* Calls to const functions cannot access any global registers and
+	     calls to pure functions cannot set them.  All other calls may
+	     reference any of the global registers, so they are recorded as
+	     used. */
+	  if (!RTL_CONST_CALL_P (insn_info->insn))
+	    {
+	      df_ref_record (DF_REF_BASE, collection_rec, regno_reg_rtx[i],
+			     NULL, bb, insn_info, DF_REF_REG_USE, flags);
+	      if (!RTL_PURE_CALL_P (insn_info->insn))
+		df_ref_record (DF_REF_BASE, collection_rec, regno_reg_rtx[i],
+			       NULL, bb, insn_info, DF_REF_REG_DEF, flags);
+	    }
+	}
+      else if (TEST_HARD_REG_BIT (regs_invalidated_by_call, i)
+	       /* no clobbers for regs that are the result of the call */
+	       && !TEST_HARD_REG_BIT (defs_generated, i)
+	       && (!is_sibling_call
+		   || !bitmap_bit_p (df->exit_block_uses, i)
+		   || refers_to_regno_p (i, i+1,
+				         crtl->return_rtx, NULL)))
+	  df_ref_record (DF_REF_BASE, collection_rec, regno_reg_rtx[i],
+			 NULL, bb, insn_info, DF_REF_REG_DEF,
+			 DF_REF_MAY_CLOBBER | flags);
+    }
+
+  /* Record the registers used to pass arguments, and explicitly
+     noted as clobbered.  */
+  for (note = CALL_INSN_FUNCTION_USAGE (insn_info->insn); note;
+       note = XEXP (note, 1))
+    {
+      if (GET_CODE (XEXP (note, 0)) == USE)
+        df_uses_record (collection_rec, &XEXP (XEXP (note, 0), 0),
+			DF_REF_REG_USE, bb, insn_info, flags);
+      else if (GET_CODE (XEXP (note, 0)) == CLOBBER)
+	{
+	  if (REG_P (XEXP (XEXP (note, 0), 0)))
+	    {
+	      unsigned int regno = REGNO (XEXP (XEXP (note, 0), 0));
+	      if (!TEST_HARD_REG_BIT (defs_generated, regno))
+		df_defs_record (collection_rec, XEXP (note, 0), bb,
+				insn_info, flags);
+	    }
+	  else
+	    df_uses_record (collection_rec, &XEXP (note, 0),
+		            DF_REF_REG_USE, bb, insn_info, flags);
+	}
+    }
+
+  return;
+}
+
+/* Collect all refs in the INSN. This function is free of any
+   side-effect - it will create and return a lists of df_ref's in the
+   COLLECTION_REC without putting those refs into existing ref chains
+   and reg chains. */
+
+static void
+df_insn_refs_collect (struct df_collection_rec *collection_rec,
+		      basic_block bb, struct df_insn_info *insn_info)
+{
+  rtx note;
+  bool is_cond_exec = (GET_CODE (PATTERN (insn_info->insn)) == COND_EXEC);
+
+  /* Clear out the collection record.  */
+  collection_rec->def_vec.truncate (0);
+  collection_rec->use_vec.truncate (0);
+  collection_rec->eq_use_vec.truncate (0);
+  collection_rec->mw_vec.truncate (0);
+
+  /* Process REG_EQUIV/REG_EQUAL notes.  */
+  for (note = REG_NOTES (insn_info->insn); note;
+       note = XEXP (note, 1))
+    {
+      switch (REG_NOTE_KIND (note))
+        {
+        case REG_EQUIV:
+        case REG_EQUAL:
+          df_uses_record (collection_rec,
+                          &XEXP (note, 0), DF_REF_REG_USE,
+                          bb, insn_info, DF_REF_IN_NOTE);
+          break;
+        case REG_NON_LOCAL_GOTO:
+          /* The frame ptr is used by a non-local goto.  */
+          df_ref_record (DF_REF_BASE, collection_rec,
+                         regno_reg_rtx[FRAME_POINTER_REGNUM],
+                         NULL, bb, insn_info,
+                         DF_REF_REG_USE, 0);
+#if !HARD_FRAME_POINTER_IS_FRAME_POINTER
+          df_ref_record (DF_REF_BASE, collection_rec,
+                         regno_reg_rtx[HARD_FRAME_POINTER_REGNUM],
+                         NULL, bb, insn_info,
+                         DF_REF_REG_USE, 0);
+#endif
+          break;
+        default:
+          break;
+        }
+    }
+
+  /* For CALL_INSNs, first record DF_REF_BASE register defs, as well as
+     uses from CALL_INSN_FUNCTION_USAGE. */
+  if (CALL_P (insn_info->insn))
+    df_get_call_refs (collection_rec, bb, insn_info,
+		      (is_cond_exec) ? DF_REF_CONDITIONAL : 0);
+
+  /* Record other defs.  These should be mostly for DF_REF_REGULAR, so
+     that a qsort on the defs is unnecessary in most cases.  */
+  df_defs_record (collection_rec,
+		  PATTERN (insn_info->insn), bb, insn_info, 0);
+
+  /* Record the register uses.  */
+  df_uses_record (collection_rec,
+		  &PATTERN (insn_info->insn), DF_REF_REG_USE, bb, insn_info, 0);
+
+  /* DF_REF_CONDITIONAL needs corresponding USES. */
+  if (is_cond_exec)
+    df_get_conditional_uses (collection_rec);
+
+  df_canonize_collection_rec (collection_rec);
+}
+
+/* Recompute the luids for the insns in BB.  */
+
+void
+df_recompute_luids (basic_block bb)
+{
+  rtx insn;
+  int luid = 0;
+
+  df_grow_insn_info ();
+
+  /* Scan the block an insn at a time from beginning to end.  */
+  FOR_BB_INSNS (bb, insn)
+    {
+      struct df_insn_info *insn_info = DF_INSN_INFO_GET (insn);
+      /* Inserting labels does not always trigger the incremental
+	 rescanning.  */
+      if (!insn_info)
+	{
+	  gcc_assert (!INSN_P (insn));
+	  insn_info = df_insn_create_insn_record (insn);
+	}
+
+      DF_INSN_INFO_LUID (insn_info) = luid;
+      if (INSN_P (insn))
+	luid++;
+    }
+}
+
+
+/* Collect all artificial refs at the block level for BB and add them
+   to COLLECTION_REC.  */
+
+static void
+df_bb_refs_collect (struct df_collection_rec *collection_rec, basic_block bb)
+{
+  collection_rec->def_vec.truncate (0);
+  collection_rec->use_vec.truncate (0);
+  collection_rec->eq_use_vec.truncate (0);
+  collection_rec->mw_vec.truncate (0);
+
+  if (bb->index == ENTRY_BLOCK)
+    {
+      df_entry_block_defs_collect (collection_rec, df->entry_block_defs);
+      return;
+    }
+  else if (bb->index == EXIT_BLOCK)
+    {
+      df_exit_block_uses_collect (collection_rec, df->exit_block_uses);
+      return;
+    }
+
+#ifdef EH_RETURN_DATA_REGNO
+  if (bb_has_eh_pred (bb))
+    {
+      unsigned int i;
+      /* Mark the registers that will contain data for the handler.  */
+      for (i = 0; ; ++i)
+	{
+	  unsigned regno = EH_RETURN_DATA_REGNO (i);
+	  if (regno == INVALID_REGNUM)
+	    break;
+	  df_ref_record (DF_REF_ARTIFICIAL, collection_rec, regno_reg_rtx[regno], NULL,
+			 bb, NULL, DF_REF_REG_DEF, DF_REF_AT_TOP);
+	}
+    }
+#endif
+
+  /* Add the hard_frame_pointer if this block is the target of a
+     non-local goto.  */
+  if (bb->flags & BB_NON_LOCAL_GOTO_TARGET)
+    df_ref_record (DF_REF_ARTIFICIAL, collection_rec, hard_frame_pointer_rtx, NULL,
+		   bb, NULL, DF_REF_REG_DEF, DF_REF_AT_TOP);
+
+  /* Add the artificial uses.  */
+  if (bb->index >= NUM_FIXED_BLOCKS)
+    {
+      bitmap_iterator bi;
+      unsigned int regno;
+      bitmap au = bb_has_eh_pred (bb)
+	? &df->eh_block_artificial_uses
+	: &df->regular_block_artificial_uses;
+
+      EXECUTE_IF_SET_IN_BITMAP (au, 0, regno, bi)
+	{
+	  df_ref_record (DF_REF_ARTIFICIAL, collection_rec, regno_reg_rtx[regno], NULL,
+			 bb, NULL, DF_REF_REG_USE, 0);
+	}
+    }
+
+  df_canonize_collection_rec (collection_rec);
+}
+
+
+/* Record all the refs within the basic block BB_INDEX and scan the instructions if SCAN_INSNS.  */
+
+void
+df_bb_refs_record (int bb_index, bool scan_insns)
+{
+  basic_block bb = BASIC_BLOCK_FOR_FN (cfun, bb_index);
+  rtx insn;
+  int luid = 0;
+
+  if (!df)
+    return;
+
+  df_collection_rec collection_rec;
+  df_grow_bb_info (df_scan);
+  if (scan_insns)
+    /* Scan the block an insn at a time from beginning to end.  */
+    FOR_BB_INSNS (bb, insn)
+      {
+	struct df_insn_info *insn_info = DF_INSN_INFO_GET (insn);
+	gcc_assert (!insn_info);
+
+	insn_info = df_insn_create_insn_record (insn);
+	if (INSN_P (insn))
+	  {
+	    /* Record refs within INSN.  */
+	    DF_INSN_INFO_LUID (insn_info) = luid++;
+	    df_insn_refs_collect (&collection_rec, bb, DF_INSN_INFO_GET (insn));
+	    df_refs_add_to_chains (&collection_rec, bb, insn, copy_all);
+	  }
+	DF_INSN_INFO_LUID (insn_info) = luid;
+      }
+
+  /* Other block level artificial refs */
+  df_bb_refs_collect (&collection_rec, bb);
+  df_refs_add_to_chains (&collection_rec, bb, NULL, copy_all);
+
+  /* Now that the block has been processed, set the block as dirty so
+     LR and LIVE will get it processed.  */
+  df_set_bb_dirty (bb);
+}
+
+
+/* Get the artificial use set for a regular (i.e. non-exit/non-entry)
+   block. */
+
+static void
+df_get_regular_block_artificial_uses (bitmap regular_block_artificial_uses)
+{
+#ifdef EH_USES
+  unsigned int i;
+#endif
+
+  bitmap_clear (regular_block_artificial_uses);
+
+  if (reload_completed)
+    {
+      if (frame_pointer_needed)
+	bitmap_set_bit (regular_block_artificial_uses, HARD_FRAME_POINTER_REGNUM);
+    }
+  else
+    /* Before reload, there are a few registers that must be forced
+       live everywhere -- which might not already be the case for
+       blocks within infinite loops.  */
+    {
+      unsigned int picreg = PIC_OFFSET_TABLE_REGNUM;
+
+      /* Any reference to any pseudo before reload is a potential
+	 reference of the frame pointer.  */
+      bitmap_set_bit (regular_block_artificial_uses, FRAME_POINTER_REGNUM);
+
+#if !HARD_FRAME_POINTER_IS_FRAME_POINTER
+      bitmap_set_bit (regular_block_artificial_uses, HARD_FRAME_POINTER_REGNUM);
+#endif
+
+#if FRAME_POINTER_REGNUM != ARG_POINTER_REGNUM
+      /* Pseudos with argument area equivalences may require
+	 reloading via the argument pointer.  */
+      if (fixed_regs[ARG_POINTER_REGNUM])
+	bitmap_set_bit (regular_block_artificial_uses, ARG_POINTER_REGNUM);
+#endif
+
+      /* Any constant, or pseudo with constant equivalences, may
+	 require reloading from memory using the pic register.  */
+      if (picreg != INVALID_REGNUM
+	  && fixed_regs[picreg])
+	bitmap_set_bit (regular_block_artificial_uses, picreg);
+    }
+  /* The all-important stack pointer must always be live.  */
+  bitmap_set_bit (regular_block_artificial_uses, STACK_POINTER_REGNUM);
+
+#ifdef EH_USES
+  /* EH_USES registers are used:
+     1) at all insns that might throw (calls or with -fnon-call-exceptions
+	trapping insns)
+     2) in all EH edges
+     3) to support backtraces and/or debugging, anywhere between their
+	initialization and where they the saved registers are restored
+	from them, including the cases where we don't reach the epilogue
+	(noreturn call or infinite loop).  */
+  for (i = 0; i < FIRST_PSEUDO_REGISTER; i++)
+    if (EH_USES (i))
+      bitmap_set_bit (regular_block_artificial_uses, i);
+#endif
+}
+
+
+/* Get the artificial use set for an eh block. */
+
+static void
+df_get_eh_block_artificial_uses (bitmap eh_block_artificial_uses)
+{
+  bitmap_clear (eh_block_artificial_uses);
+
+  /* The following code (down through the arg_pointer setting APPEARS
+     to be necessary because there is nothing that actually
+     describes what the exception handling code may actually need
+     to keep alive.  */
+  if (reload_completed)
+    {
+      if (frame_pointer_needed)
+	{
+	  bitmap_set_bit (eh_block_artificial_uses, FRAME_POINTER_REGNUM);
+#if !HARD_FRAME_POINTER_IS_FRAME_POINTER
+	  bitmap_set_bit (eh_block_artificial_uses, HARD_FRAME_POINTER_REGNUM);
+#endif
+	}
+#if FRAME_POINTER_REGNUM != ARG_POINTER_REGNUM
+      if (fixed_regs[ARG_POINTER_REGNUM])
+	bitmap_set_bit (eh_block_artificial_uses, ARG_POINTER_REGNUM);
+#endif
+    }
+}
+
+
+
+/*----------------------------------------------------------------------------
+   Specialized hard register scanning functions.
+----------------------------------------------------------------------------*/
+
+
+/* Mark a register in SET.  Hard registers in large modes get all
+   of their component registers set as well.  */
+
+static void
+df_mark_reg (rtx reg, void *vset)
+{
+  bitmap set = (bitmap) vset;
+  int regno = REGNO (reg);
+
+  gcc_assert (GET_MODE (reg) != BLKmode);
+
+  if (regno < FIRST_PSEUDO_REGISTER)
+    {
+      int n = hard_regno_nregs[regno][GET_MODE (reg)];
+      bitmap_set_range (set, regno, n);
+    }
+  else
+    bitmap_set_bit (set, regno);
+}
+
+
+/* Set the bit for regs that are considered being defined at the entry. */
+
+static void
+df_get_entry_block_def_set (bitmap entry_block_defs)
+{
+  rtx r;
+  int i;
+
+  bitmap_clear (entry_block_defs);
+
+  for (i = 0; i < FIRST_PSEUDO_REGISTER; i++)
+    {
+      if (global_regs[i])
+	bitmap_set_bit (entry_block_defs, i);
+      if (FUNCTION_ARG_REGNO_P (i))
+	bitmap_set_bit (entry_block_defs, INCOMING_REGNO (i));
+    }
+
+  /* The always important stack pointer.  */
+  bitmap_set_bit (entry_block_defs, STACK_POINTER_REGNUM);
+
+  /* Once the prologue has been generated, all of these registers
+     should just show up in the first regular block.  */
+  if (HAVE_prologue && epilogue_completed)
+    {
+      /* Defs for the callee saved registers are inserted so that the
+	 pushes have some defining location.  */
+      for (i = 0; i < FIRST_PSEUDO_REGISTER; i++)
+	if ((call_used_regs[i] == 0) && (df_regs_ever_live_p (i)))
+	  bitmap_set_bit (entry_block_defs, i);
+    }
+
+  r = targetm.calls.struct_value_rtx (current_function_decl, true);
+  if (r && REG_P (r))
+    bitmap_set_bit (entry_block_defs, REGNO (r));
+
+  /* If the function has an incoming STATIC_CHAIN, it has to show up
+     in the entry def set.  */
+  r = targetm.calls.static_chain (current_function_decl, true);
+  if (r && REG_P (r))
+    bitmap_set_bit (entry_block_defs, REGNO (r));
+
+  if ((!reload_completed) || frame_pointer_needed)
+    {
+      /* Any reference to any pseudo before reload is a potential
+	 reference of the frame pointer.  */
+      bitmap_set_bit (entry_block_defs, FRAME_POINTER_REGNUM);
+#if !HARD_FRAME_POINTER_IS_FRAME_POINTER
+      /* If they are different, also mark the hard frame pointer as live.  */
+      if (!LOCAL_REGNO (HARD_FRAME_POINTER_REGNUM))
+	bitmap_set_bit (entry_block_defs, HARD_FRAME_POINTER_REGNUM);
+#endif
+    }
+
+  /* These registers are live everywhere.  */
+  if (!reload_completed)
+    {
+#ifdef PIC_OFFSET_TABLE_REGNUM
+      unsigned int picreg = PIC_OFFSET_TABLE_REGNUM;
+#endif
+
+#if FRAME_POINTER_REGNUM != ARG_POINTER_REGNUM
+      /* Pseudos with argument area equivalences may require
+	 reloading via the argument pointer.  */
+      if (fixed_regs[ARG_POINTER_REGNUM])
+	bitmap_set_bit (entry_block_defs, ARG_POINTER_REGNUM);
+#endif
+
+#ifdef PIC_OFFSET_TABLE_REGNUM
+      /* Any constant, or pseudo with constant equivalences, may
+	 require reloading from memory using the pic register.  */
+      if (picreg != INVALID_REGNUM
+	  && fixed_regs[picreg])
+	bitmap_set_bit (entry_block_defs, picreg);
+#endif
+    }
+
+#ifdef INCOMING_RETURN_ADDR_RTX
+  if (REG_P (INCOMING_RETURN_ADDR_RTX))
+    bitmap_set_bit (entry_block_defs, REGNO (INCOMING_RETURN_ADDR_RTX));
+#endif
+
+  targetm.extra_live_on_entry (entry_block_defs);
+}
+
+
+/* Return the (conservative) set of hard registers that are defined on
+   entry to the function.
+   It uses df->entry_block_defs to determine which register
+   reference to include.  */
+
+static void
+df_entry_block_defs_collect (struct df_collection_rec *collection_rec,
+			     bitmap entry_block_defs)
+{
+  unsigned int i;
+  bitmap_iterator bi;
+
+  EXECUTE_IF_SET_IN_BITMAP (entry_block_defs, 0, i, bi)
+    {
+      df_ref_record (DF_REF_ARTIFICIAL, collection_rec, regno_reg_rtx[i], NULL,
+		     ENTRY_BLOCK_PTR_FOR_FN (cfun), NULL, DF_REF_REG_DEF, 0);
+    }
+
+  df_canonize_collection_rec (collection_rec);
+}
+
+
+/* Record the (conservative) set of hard registers that are defined on
+   entry to the function.  */
+
+static void
+df_record_entry_block_defs (bitmap entry_block_defs)
+{
+  struct df_collection_rec collection_rec;
+  df_entry_block_defs_collect (&collection_rec, entry_block_defs);
+
+  /* Process bb_refs chain */
+  df_refs_add_to_chains (&collection_rec,
+			 BASIC_BLOCK_FOR_FN (cfun, ENTRY_BLOCK),
+			 NULL,
+			 copy_defs);
+}
+
+
+/* Update the defs in the entry block.  */
+
+void
+df_update_entry_block_defs (void)
+{
+  bitmap_head refs;
+  bool changed = false;
+
+  bitmap_initialize (&refs, &df_bitmap_obstack);
+  df_get_entry_block_def_set (&refs);
+  if (df->entry_block_defs)
+    {
+      if (!bitmap_equal_p (df->entry_block_defs, &refs))
+	{
+	  struct df_scan_bb_info *bb_info = df_scan_get_bb_info (ENTRY_BLOCK);
+	  df_ref_chain_delete_du_chain (bb_info->artificial_defs);
+	  df_ref_chain_delete (bb_info->artificial_defs);
+	  bb_info->artificial_defs = NULL;
+	  changed = true;
+	}
+    }
+  else
+    {
+      struct df_scan_problem_data *problem_data
+	= (struct df_scan_problem_data *) df_scan->problem_data;
+	gcc_unreachable ();
+      df->entry_block_defs = BITMAP_ALLOC (&problem_data->reg_bitmaps);
+      changed = true;
+    }
+
+  if (changed)
+    {
+      df_record_entry_block_defs (&refs);
+      bitmap_copy (df->entry_block_defs, &refs);
+      df_set_bb_dirty (BASIC_BLOCK_FOR_FN (cfun, ENTRY_BLOCK));
+    }
+  bitmap_clear (&refs);
+}
+
+
+/* Set the bit for regs that are considered being used at the exit. */
+
+static void
+df_get_exit_block_use_set (bitmap exit_block_uses)
+{
+  unsigned int i;
+  unsigned int picreg = PIC_OFFSET_TABLE_REGNUM;
+
+  bitmap_clear (exit_block_uses);
+
+  /* Stack pointer is always live at the exit.  */
+  bitmap_set_bit (exit_block_uses, STACK_POINTER_REGNUM);
+
+  /* Mark the frame pointer if needed at the end of the function.
+     If we end up eliminating it, it will be removed from the live
+     list of each basic block by reload.  */
+
+  if ((!reload_completed) || frame_pointer_needed)
+    {
+      bitmap_set_bit (exit_block_uses, FRAME_POINTER_REGNUM);
+#if !HARD_FRAME_POINTER_IS_FRAME_POINTER
+      /* If they are different, also mark the hard frame pointer as live.  */
+      if (!LOCAL_REGNO (HARD_FRAME_POINTER_REGNUM))
+	bitmap_set_bit (exit_block_uses, HARD_FRAME_POINTER_REGNUM);
+#endif
+    }
+
+  /* Many architectures have a GP register even without flag_pic.
+     Assume the pic register is not in use, or will be handled by
+     other means, if it is not fixed.  */
+  if (!PIC_OFFSET_TABLE_REG_CALL_CLOBBERED
+      && picreg != INVALID_REGNUM
+      && fixed_regs[picreg])
+    bitmap_set_bit (exit_block_uses, picreg);
+
+  /* Mark all global registers, and all registers used by the
+     epilogue as being live at the end of the function since they
+     may be referenced by our caller.  */
+  for (i = 0; i < FIRST_PSEUDO_REGISTER; i++)
+    if (global_regs[i] || EPILOGUE_USES (i))
+      bitmap_set_bit (exit_block_uses, i);
+
+  if (HAVE_epilogue && epilogue_completed)
+    {
+      /* Mark all call-saved registers that we actually used.  */
+      for (i = 0; i < FIRST_PSEUDO_REGISTER; i++)
+	if (df_regs_ever_live_p (i) && !LOCAL_REGNO (i)
+	    && !TEST_HARD_REG_BIT (regs_invalidated_by_call, i))
+	  bitmap_set_bit (exit_block_uses, i);
+    }
+
+#ifdef EH_RETURN_DATA_REGNO
+  /* Mark the registers that will contain data for the handler.  */
+  if (reload_completed && crtl->calls_eh_return)
+    for (i = 0; ; ++i)
+      {
+	unsigned regno = EH_RETURN_DATA_REGNO (i);
+	if (regno == INVALID_REGNUM)
+	  break;
+	bitmap_set_bit (exit_block_uses, regno);
+      }
+#endif
+
+#ifdef EH_RETURN_STACKADJ_RTX
+  if ((!HAVE_epilogue || ! epilogue_completed)
+      && crtl->calls_eh_return)
+    {
+      rtx tmp = EH_RETURN_STACKADJ_RTX;
+      if (tmp && REG_P (tmp))
+	df_mark_reg (tmp, exit_block_uses);
+    }
+#endif
+
+#ifdef EH_RETURN_HANDLER_RTX
+  if ((!HAVE_epilogue || ! epilogue_completed)
+      && crtl->calls_eh_return)
+    {
+      rtx tmp = EH_RETURN_HANDLER_RTX;
+      if (tmp && REG_P (tmp))
+	df_mark_reg (tmp, exit_block_uses);
+    }
+#endif
+
+  /* Mark function return value.  */
+  diddle_return_value (df_mark_reg, (void*) exit_block_uses);
+}
+
+
+/* Return the refs of hard registers that are used in the exit block.
+   It uses df->exit_block_uses to determine register to include.  */
+
+static void
+df_exit_block_uses_collect (struct df_collection_rec *collection_rec, bitmap exit_block_uses)
+{
+  unsigned int i;
+  bitmap_iterator bi;
+
+  EXECUTE_IF_SET_IN_BITMAP (exit_block_uses, 0, i, bi)
+    df_ref_record (DF_REF_ARTIFICIAL, collection_rec, regno_reg_rtx[i], NULL,
+		   EXIT_BLOCK_PTR_FOR_FN (cfun), NULL, DF_REF_REG_USE, 0);
+
+#if FRAME_POINTER_REGNUM != ARG_POINTER_REGNUM
+  /* It is deliberate that this is not put in the exit block uses but
+     I do not know why.  */
+  if (reload_completed
+      && !bitmap_bit_p (exit_block_uses, ARG_POINTER_REGNUM)
+      && bb_has_eh_pred (EXIT_BLOCK_PTR_FOR_FN (cfun))
+      && fixed_regs[ARG_POINTER_REGNUM])
+    df_ref_record (DF_REF_ARTIFICIAL, collection_rec, regno_reg_rtx[ARG_POINTER_REGNUM], NULL,
+		   EXIT_BLOCK_PTR_FOR_FN (cfun), NULL, DF_REF_REG_USE, 0);
+#endif
+
+  df_canonize_collection_rec (collection_rec);
+}
+
+
+/* Record the set of hard registers that are used in the exit block.
+   It uses df->exit_block_uses to determine which bit to include.  */
+
+static void
+df_record_exit_block_uses (bitmap exit_block_uses)
+{
+  struct df_collection_rec collection_rec;
+  df_exit_block_uses_collect (&collection_rec, exit_block_uses);
+
+  /* Process bb_refs chain */
+  df_refs_add_to_chains (&collection_rec,
+			 BASIC_BLOCK_FOR_FN (cfun, EXIT_BLOCK),
+			 NULL,
+			 copy_uses);
+}
+
+
+/* Update the uses in the exit block.  */
+
+void
+df_update_exit_block_uses (void)
+{
+  bitmap_head refs;
+  bool changed = false;
+
+  bitmap_initialize (&refs, &df_bitmap_obstack);
+  df_get_exit_block_use_set (&refs);
+  if (df->exit_block_uses)
+    {
+      if (!bitmap_equal_p (df->exit_block_uses, &refs))
+	{
+	  struct df_scan_bb_info *bb_info = df_scan_get_bb_info (EXIT_BLOCK);
+	  df_ref_chain_delete_du_chain (bb_info->artificial_uses);
+	  df_ref_chain_delete (bb_info->artificial_uses);
+	  bb_info->artificial_uses = NULL;
+	  changed = true;
+	}
+    }
+  else
+    {
+      struct df_scan_problem_data *problem_data
+	= (struct df_scan_problem_data *) df_scan->problem_data;
+	gcc_unreachable ();
+      df->exit_block_uses = BITMAP_ALLOC (&problem_data->reg_bitmaps);
+      changed = true;
+    }
+
+  if (changed)
+    {
+      df_record_exit_block_uses (&refs);
+      bitmap_copy (df->exit_block_uses,& refs);
+      df_set_bb_dirty (BASIC_BLOCK_FOR_FN (cfun, EXIT_BLOCK));
+    }
+  bitmap_clear (&refs);
+}
+
+static bool initialized = false;
+
+
+/* Initialize some platform specific structures.  */
+
+void
+df_hard_reg_init (void)
+{
+#ifdef ELIMINABLE_REGS
+  int i;
+  static const struct {const int from, to; } eliminables[] = ELIMINABLE_REGS;
+#endif
+  if (initialized)
+    return;
+
+  /* Record which registers will be eliminated.  We use this in
+     mark_used_regs.  */
+  CLEAR_HARD_REG_SET (elim_reg_set);
+
+#ifdef ELIMINABLE_REGS
+  for (i = 0; i < (int) ARRAY_SIZE (eliminables); i++)
+    SET_HARD_REG_BIT (elim_reg_set, eliminables[i].from);
+#else
+  SET_HARD_REG_BIT (elim_reg_set, FRAME_POINTER_REGNUM);
+#endif
+
+  initialized = true;
+}
+
+
+/* Recompute the parts of scanning that are based on regs_ever_live
+   because something changed in that array.  */
+
+void
+df_update_entry_exit_and_calls (void)
+{
+  basic_block bb;
+
+  df_update_entry_block_defs ();
+  df_update_exit_block_uses ();
+
+  /* The call insns need to be rescanned because there may be changes
+     in the set of registers clobbered across the call.  */
+  FOR_EACH_BB_FN (bb, cfun)
+    {
+      rtx insn;
+      FOR_BB_INSNS (bb, insn)
+	{
+	  if (INSN_P (insn) && CALL_P (insn))
+	    df_insn_rescan (insn);
+	}
+    }
+}
+
+
+/* Return true if hard REG is actually used in the some instruction.
+   There are a fair number of conditions that affect the setting of
+   this array.  See the comment in df.h for df->hard_regs_live_count
+   for the conditions that this array is set. */
+
+bool
+df_hard_reg_used_p (unsigned int reg)
+{
+  return df->hard_regs_live_count[reg] != 0;
+}
+
+
+/* A count of the number of times REG is actually used in the some
+   instruction.  There are a fair number of conditions that affect the
+   setting of this array.  See the comment in df.h for
+   df->hard_regs_live_count for the conditions that this array is
+   set. */
+
+
+unsigned int
+df_hard_reg_used_count (unsigned int reg)
+{
+  return df->hard_regs_live_count[reg];
+}
+
+
+/* Get the value of regs_ever_live[REGNO].  */
+
+bool
+df_regs_ever_live_p (unsigned int regno)
+{
+  return regs_ever_live[regno];
+}
+
+
+/* Set regs_ever_live[REGNO] to VALUE.  If this cause regs_ever_live
+   to change, schedule that change for the next update.  */
+
+void
+df_set_regs_ever_live (unsigned int regno, bool value)
+{
+  if (regs_ever_live[regno] == value)
+    return;
+
+  regs_ever_live[regno] = value;
+  if (df)
+    df->redo_entry_and_exit = true;
+}
+
+
+/* Compute "regs_ever_live" information from the underlying df
+   information.  Set the vector to all false if RESET.  */
+
+void
+df_compute_regs_ever_live (bool reset)
+{
+  unsigned int i;
+  bool changed = df->redo_entry_and_exit;
+
+  if (reset)
+    memset (regs_ever_live, 0, sizeof (regs_ever_live));
+
+  for (i = 0; i < FIRST_PSEUDO_REGISTER; i++)
+    if ((!regs_ever_live[i]) && df_hard_reg_used_p (i))
+      {
+	regs_ever_live[i] = true;
+	changed = true;
+      }
+  if (changed)
+    df_update_entry_exit_and_calls ();
+  df->redo_entry_and_exit = false;
+}
+
+
+/*----------------------------------------------------------------------------
+  Dataflow ref information verification functions.
+
+  df_reg_chain_mark (refs, regno, is_def, is_eq_use)
+  df_reg_chain_verify_unmarked (refs)
+  df_refs_verify (vec<stack, va_df_ref>, ref*, bool)
+  df_mws_verify (mw*, mw*, bool)
+  df_insn_refs_verify (collection_rec, bb, insn, bool)
+  df_bb_refs_verify (bb, refs, bool)
+  df_bb_verify (bb)
+  df_exit_block_bitmap_verify (bool)
+  df_entry_block_bitmap_verify (bool)
+  df_scan_verify ()
+----------------------------------------------------------------------------*/
+
+
+/* Mark all refs in the reg chain.  Verify that all of the registers
+are in the correct chain.  */
+
+static unsigned int
+df_reg_chain_mark (df_ref refs, unsigned int regno,
+		   bool is_def, bool is_eq_use)
+{
+  unsigned int count = 0;
+  df_ref ref;
+  for (ref = refs; ref; ref = DF_REF_NEXT_REG (ref))
+    {
+      gcc_assert (!DF_REF_IS_REG_MARKED (ref));
+
+      /* If there are no def-use or use-def chains, make sure that all
+	 of the chains are clear.  */
+      if (!df_chain)
+	gcc_assert (!DF_REF_CHAIN (ref));
+
+      /* Check to make sure the ref is in the correct chain.  */
+      gcc_assert (DF_REF_REGNO (ref) == regno);
+      if (is_def)
+	gcc_assert (DF_REF_REG_DEF_P (ref));
+      else
+	gcc_assert (!DF_REF_REG_DEF_P (ref));
+
+      if (is_eq_use)
+	gcc_assert ((DF_REF_FLAGS (ref) & DF_REF_IN_NOTE));
+      else
+	gcc_assert ((DF_REF_FLAGS (ref) & DF_REF_IN_NOTE) == 0);
+
+      if (DF_REF_NEXT_REG (ref))
+	gcc_assert (DF_REF_PREV_REG (DF_REF_NEXT_REG (ref)) == ref);
+      count++;
+      DF_REF_REG_MARK (ref);
+    }
+  return count;
+}
+
+
+/* Verify that all of the registers in the chain are unmarked.  */
+
+static void
+df_reg_chain_verify_unmarked (df_ref refs)
+{
+  df_ref ref;
+  for (ref = refs; ref; ref = DF_REF_NEXT_REG (ref))
+    gcc_assert (!DF_REF_IS_REG_MARKED (ref));
+}
+
+
+/* Verify that NEW_REC and OLD_REC have exactly the same members. */
+
+static bool
+df_refs_verify (const vec<df_ref, va_heap> *new_rec, df_ref *old_rec,
+		bool abort_if_fail)
+{
+  unsigned int ix;
+  df_ref new_ref;
+
+  FOR_EACH_VEC_ELT (*new_rec, ix, new_ref)
+    {
+      if (*old_rec == NULL || !df_ref_equal_p (new_ref, *old_rec))
+	{
+	  if (abort_if_fail)
+	    gcc_assert (0);
+	  else
+	    return false;
+	}
+
+      /* Abort if fail is called from the function level verifier.  If
+	 that is the context, mark this reg as being seem.  */
+      if (abort_if_fail)
+	{
+	  gcc_assert (DF_REF_IS_REG_MARKED (*old_rec));
+	  DF_REF_REG_UNMARK (*old_rec);
+	}
+
+      old_rec++;
+    }
+
+  if (abort_if_fail)
+    gcc_assert (*old_rec == NULL);
+  else
+    return *old_rec == NULL;
+  return false;
+}
+
+
+/* Verify that NEW_REC and OLD_REC have exactly the same members. */
+
+static bool
+df_mws_verify (const vec<df_mw_hardreg_ptr, va_heap> *new_rec,
+	       struct df_mw_hardreg **old_rec,
+	       bool abort_if_fail)
+{
+  unsigned int ix;
+  struct df_mw_hardreg *new_reg;
+
+  FOR_EACH_VEC_ELT (*new_rec, ix, new_reg)
+    {
+      if (*old_rec == NULL || !df_mw_equal_p (new_reg, *old_rec))
+	{
+	  if (abort_if_fail)
+	    gcc_assert (0);
+	  else
+	    return false;
+	}
+      old_rec++;
+    }
+
+  if (abort_if_fail)
+    gcc_assert (*old_rec == NULL);
+  else
+    return *old_rec == NULL;
+  return false;
+}
+
+
+/* Return true if the existing insn refs information is complete and
+   correct. Otherwise (i.e. if there's any missing or extra refs),
+   return the correct df_ref chain in REFS_RETURN.
+
+   If ABORT_IF_FAIL, leave the refs that are verified (already in the
+   ref chain) as DF_REF_MARKED(). If it's false, then it's a per-insn
+   verification mode instead of the whole function, so unmark
+   everything.
+
+   If ABORT_IF_FAIL is set, this function never returns false.  */
+
+static bool
+df_insn_refs_verify (struct df_collection_rec *collection_rec,
+		     basic_block bb,
+                     rtx insn,
+		     bool abort_if_fail)
+{
+  bool ret1, ret2, ret3, ret4;
+  unsigned int uid = INSN_UID (insn);
+  struct df_insn_info *insn_info = DF_INSN_INFO_GET (insn);
+
+  df_insn_refs_collect (collection_rec, bb, insn_info);
+
+  if (!DF_INSN_UID_DEFS (uid))
+    {
+      /* The insn_rec was created but it was never filled out.  */
+      if (abort_if_fail)
+	gcc_assert (0);
+      else
+	return false;
+    }
+
+  /* Unfortunately we cannot opt out early if one of these is not
+     right because the marks will not get cleared.  */
+  ret1 = df_refs_verify (&collection_rec->def_vec, DF_INSN_UID_DEFS (uid),
+			 abort_if_fail);
+  ret2 = df_refs_verify (&collection_rec->use_vec, DF_INSN_UID_USES (uid),
+			 abort_if_fail);
+  ret3 = df_refs_verify (&collection_rec->eq_use_vec, DF_INSN_UID_EQ_USES (uid),
+			 abort_if_fail);
+  ret4 = df_mws_verify (&collection_rec->mw_vec, DF_INSN_UID_MWS (uid),
+		       abort_if_fail);
+  return (ret1 && ret2 && ret3 && ret4);
+}
+
+
+/* Return true if all refs in the basic block are correct and complete.
+   Due to df_ref_chain_verify, it will cause all refs
+   that are verified to have DF_REF_MARK bit set.  */
+
+static bool
+df_bb_verify (basic_block bb)
+{
+  rtx insn;
+  struct df_scan_bb_info *bb_info = df_scan_get_bb_info (bb->index);
+  struct df_collection_rec collection_rec;
+
+  gcc_assert (bb_info);
+
+  /* Scan the block, one insn at a time, from beginning to end.  */
+  FOR_BB_INSNS_REVERSE (bb, insn)
+    {
+      if (!INSN_P (insn))
+        continue;
+      df_insn_refs_verify (&collection_rec, bb, insn, true);
+      df_free_collection_rec (&collection_rec);
+    }
+
+  /* Do the artificial defs and uses.  */
+  df_bb_refs_collect (&collection_rec, bb);
+  df_refs_verify (&collection_rec.def_vec, df_get_artificial_defs (bb->index), true);
+  df_refs_verify (&collection_rec.use_vec, df_get_artificial_uses (bb->index), true);
+  df_free_collection_rec (&collection_rec);
+
+  return true;
+}
+
+
+/* Returns true if the entry block has correct and complete df_ref set.
+   If not it either aborts if ABORT_IF_FAIL is true or returns false.  */
+
+static bool
+df_entry_block_bitmap_verify (bool abort_if_fail)
+{
+  bitmap_head entry_block_defs;
+  bool is_eq;
+
+  bitmap_initialize (&entry_block_defs, &df_bitmap_obstack);
+  df_get_entry_block_def_set (&entry_block_defs);
+
+  is_eq = bitmap_equal_p (&entry_block_defs, df->entry_block_defs);
+
+  if (!is_eq && abort_if_fail)
+    {
+      fprintf (stderr, "entry_block_defs = ");
+      df_print_regset (stderr, &entry_block_defs);
+      fprintf (stderr, "df->entry_block_defs = ");
+      df_print_regset (stderr, df->entry_block_defs);
+      gcc_assert (0);
+    }
+
+  bitmap_clear (&entry_block_defs);
+
+  return is_eq;
+}
+
+
+/* Returns true if the exit block has correct and complete df_ref set.
+   If not it either aborts if ABORT_IF_FAIL is true or returns false. */
+
+static bool
+df_exit_block_bitmap_verify (bool abort_if_fail)
+{
+  bitmap_head exit_block_uses;
+  bool is_eq;
+
+  bitmap_initialize (&exit_block_uses, &df_bitmap_obstack);
+  df_get_exit_block_use_set (&exit_block_uses);
+
+  is_eq = bitmap_equal_p (&exit_block_uses, df->exit_block_uses);
+
+  if (!is_eq && abort_if_fail)
+    {
+      fprintf (stderr, "exit_block_uses = ");
+      df_print_regset (stderr, &exit_block_uses);
+      fprintf (stderr, "df->exit_block_uses = ");
+      df_print_regset (stderr, df->exit_block_uses);
+      gcc_assert (0);
+    }
+
+  bitmap_clear (&exit_block_uses);
+
+  return is_eq;
+}
+
+
+/* Return true if df_ref information for all insns in all blocks are
+   correct and complete.  */
+
+void
+df_scan_verify (void)
+{
+  unsigned int i;
+  basic_block bb;
+  bitmap_head regular_block_artificial_uses;
+  bitmap_head eh_block_artificial_uses;
+
+  if (!df)
+    return;
+
+  /* Verification is a 4 step process. */
+
+  /* (1) All of the refs are marked by going through the reg chains.  */
+  for (i = 0; i < DF_REG_SIZE (df); i++)
+    {
+      gcc_assert (df_reg_chain_mark (DF_REG_DEF_CHAIN (i), i, true, false)
+		  == DF_REG_DEF_COUNT (i));
+      gcc_assert (df_reg_chain_mark (DF_REG_USE_CHAIN (i), i, false, false)
+		  == DF_REG_USE_COUNT (i));
+      gcc_assert (df_reg_chain_mark (DF_REG_EQ_USE_CHAIN (i), i, false, true)
+		  == DF_REG_EQ_USE_COUNT (i));
+    }
+
+  /* (2) There are various bitmaps whose value may change over the
+     course of the compilation.  This step recomputes them to make
+     sure that they have not slipped out of date.  */
+  bitmap_initialize (&regular_block_artificial_uses, &df_bitmap_obstack);
+  bitmap_initialize (&eh_block_artificial_uses, &df_bitmap_obstack);
+
+  df_get_regular_block_artificial_uses (&regular_block_artificial_uses);
+  df_get_eh_block_artificial_uses (&eh_block_artificial_uses);
+
+  bitmap_ior_into (&eh_block_artificial_uses,
+		   &regular_block_artificial_uses);
+
+  /* Check artificial_uses bitmaps didn't change. */
+  gcc_assert (bitmap_equal_p (&regular_block_artificial_uses,
+			      &df->regular_block_artificial_uses));
+  gcc_assert (bitmap_equal_p (&eh_block_artificial_uses,
+			      &df->eh_block_artificial_uses));
+
+  bitmap_clear (&regular_block_artificial_uses);
+  bitmap_clear (&eh_block_artificial_uses);
+
+  /* Verify entry block and exit block. These only verify the bitmaps,
+     the refs are verified in df_bb_verify.  */
+  df_entry_block_bitmap_verify (true);
+  df_exit_block_bitmap_verify (true);
+
+  /* (3) All of the insns in all of the blocks are traversed and the
+     marks are cleared both in the artificial refs attached to the
+     blocks and the real refs inside the insns.  It is a failure to
+     clear a mark that has not been set as this means that the ref in
+     the block or insn was not in the reg chain.  */
+
+  FOR_ALL_BB_FN (bb, cfun)
+    df_bb_verify (bb);
+
+  /* (4) See if all reg chains are traversed a second time.  This time
+     a check is made that the marks are clear. A set mark would be a
+     from a reg that is not in any insn or basic block.  */
+
+  for (i = 0; i < DF_REG_SIZE (df); i++)
+    {
+      df_reg_chain_verify_unmarked (DF_REG_DEF_CHAIN (i));
+      df_reg_chain_verify_unmarked (DF_REG_USE_CHAIN (i));
+      df_reg_chain_verify_unmarked (DF_REG_EQ_USE_CHAIN (i));
+    }
+}