--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/gcc/df-problems.c	Fri Jul 17 14:47:48 2009 +0900
@@ -0,0 +1,3935 @@
+/* Standard problems for dataflow support routines.
+   Copyright (C) 1999, 2000, 2001, 2002, 2003, 2004, 2005, 2006, 2007,
+   2008, 2009 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 "output.h"
+#include "alloc-pool.h"
+#include "flags.h"
+#include "hard-reg-set.h"
+#include "basic-block.h"
+#include "sbitmap.h"
+#include "bitmap.h"
+#include "timevar.h"
+#include "df.h"
+#include "except.h"
+#include "dce.h"
+#include "vecprim.h"
+
+/* Note that turning REG_DEAD_DEBUGGING on will cause
+   gcc.c-torture/unsorted/dump-noaddr.c to fail because it prints
+   addresses in the dumps.  */  
+#if 0
+#define REG_DEAD_DEBUGGING
+#endif
+
+#define DF_SPARSE_THRESHOLD 32
+
+static bitmap seen_in_block = NULL;
+static bitmap seen_in_insn = NULL;
+
+
+/*----------------------------------------------------------------------------
+   Public functions access functions for the dataflow problems.
+----------------------------------------------------------------------------*/
+/* Get the live at out set for BB no matter what problem happens to be
+   defined.  This function is used by the register allocators who
+   choose different dataflow problems depending on the optimization
+   level.  */
+
+bitmap
+df_get_live_out (basic_block bb)
+{
+  gcc_assert (df_lr);
+
+  if (df_live)
+    return DF_LIVE_OUT (bb);
+  else 
+    return DF_LR_OUT (bb);
+}
+
+/* Get the live at in set for BB no matter what problem happens to be
+   defined.  This function is used by the register allocators who
+   choose different dataflow problems depending on the optimization
+   level.  */
+
+bitmap
+df_get_live_in (basic_block bb)
+{
+  gcc_assert (df_lr);
+
+  if (df_live)
+    return DF_LIVE_IN (bb);
+  else 
+    return DF_LR_IN (bb);
+}
+
+/*----------------------------------------------------------------------------
+   Utility functions.
+----------------------------------------------------------------------------*/
+
+/* Generic versions to get the void* version of the block info.  Only
+   used inside the problem instance vectors.  */
+
+/* Grow the bb_info array.  */
+
+void
+df_grow_bb_info (struct dataflow *dflow)
+{
+  unsigned int new_size = last_basic_block + 1;
+  if (dflow->block_info_size < new_size)
+    {
+      new_size += new_size / 4;
+      dflow->block_info = XRESIZEVEC (void *, dflow->block_info, new_size);
+      memset (dflow->block_info + dflow->block_info_size, 0,
+	      (new_size - dflow->block_info_size) *sizeof (void *));
+      dflow->block_info_size = new_size;
+    }
+}
+
+/* Dump a def-use or use-def chain for REF to FILE.  */
+
+void
+df_chain_dump (struct df_link *link, FILE *file)
+{
+  fprintf (file, "{ ");
+  for (; link; link = link->next)
+    {
+      fprintf (file, "%c%d(bb %d insn %d) ",
+	       DF_REF_REG_DEF_P (link->ref) ? 'd' : 'u',
+	       DF_REF_ID (link->ref),
+	       DF_REF_BBNO (link->ref),
+	       DF_REF_IS_ARTIFICIAL (link->ref) ? -1 : DF_REF_INSN_UID (link->ref));
+    }
+  fprintf (file, "}");
+}
+
+
+/* Print some basic block info as part of df_dump.  */
+
+void 
+df_print_bb_index (basic_block bb, FILE *file)
+{
+  edge e;
+  edge_iterator ei;
+
+  fprintf (file, "\n( ");
+    FOR_EACH_EDGE (e, ei, bb->preds)
+    {
+      basic_block pred = e->src;
+      fprintf (file, "%d%s ", pred->index, e->flags & EDGE_EH ? "(EH)" : "");
+    } 
+  fprintf (file, ")->[%d]->( ", bb->index);
+  FOR_EACH_EDGE (e, ei, bb->succs)
+    {
+      basic_block succ = e->dest;
+      fprintf (file, "%d%s ", succ->index, e->flags & EDGE_EH ? "(EH)" : "");
+    } 
+  fprintf (file, ")\n");
+}
+
+
+
+/* Make sure that the seen_in_insn and seen_in_block sbitmaps are set
+   up correctly. */
+
+static void
+df_set_seen (void)
+{
+  seen_in_block = BITMAP_ALLOC (&df_bitmap_obstack);
+  seen_in_insn = BITMAP_ALLOC (&df_bitmap_obstack);
+}
+
+
+static void
+df_unset_seen (void)
+{
+  BITMAP_FREE (seen_in_block);
+  BITMAP_FREE (seen_in_insn);
+}
+
+
+
+/*----------------------------------------------------------------------------
+   REACHING DEFINITIONS
+
+   Find the locations in the function where each definition site for a
+   pseudo reaches.  In and out bitvectors are built for each basic
+   block.  The id field in the ref is used to index into these sets.
+   See df.h for details.
+   ----------------------------------------------------------------------------*/
+
+/* This problem plays a large number of games for the sake of
+   efficiency.  
+   
+   1) The order of the bits in the bitvectors.  After the scanning
+   phase, all of the defs are sorted.  All of the defs for the reg 0
+   are first, followed by all defs for reg 1 and so on.
+   
+   2) There are two kill sets, one if the number of defs is less or
+   equal to DF_SPARSE_THRESHOLD and another if the number of defs is
+   greater.
+
+   <= : Data is built directly in the kill set.
+
+   > : One level of indirection is used to keep from generating long
+   strings of 1 bits in the kill sets.  Bitvectors that are indexed
+   by the regnum are used to represent that there is a killing def
+   for the register.  The confluence and transfer functions use
+   these along with the bitmap_clear_range call to remove ranges of
+   bits without actually generating a knockout vector.
+
+   The kill and sparse_kill and the dense_invalidated_by_call and
+   sparse_invalidated_by_call both play this game.  */
+
+/* Private data used to compute the solution for this problem.  These
+   data structures are not accessible outside of this module.  */
+struct df_rd_problem_data
+{
+  /* The set of defs to regs invalidated by call.  */
+  bitmap sparse_invalidated_by_call;  
+  /* The set of defs to regs invalidate by call for rd.  */  
+  bitmap dense_invalidated_by_call;
+  /* An obstack for the bitmaps we need for this problem.  */
+  bitmap_obstack rd_bitmaps;
+};
+
+/* Set basic block info.  */
+
+static void
+df_rd_set_bb_info (unsigned int index, 
+		   struct df_rd_bb_info *bb_info)
+{
+  gcc_assert (df_rd);
+  gcc_assert (index < df_rd->block_info_size);
+  df_rd->block_info[index] = bb_info;
+}
+
+
+/* Free basic block info.  */
+
+static void
+df_rd_free_bb_info (basic_block bb ATTRIBUTE_UNUSED, 
+		    void *vbb_info)
+{
+  struct df_rd_bb_info *bb_info = (struct df_rd_bb_info *) vbb_info;
+  if (bb_info)
+    {
+      BITMAP_FREE (bb_info->kill);
+      BITMAP_FREE (bb_info->sparse_kill);
+      BITMAP_FREE (bb_info->gen);
+      BITMAP_FREE (bb_info->in);
+      BITMAP_FREE (bb_info->out);
+      pool_free (df_rd->block_pool, bb_info);
+    }
+}
+
+
+/* Allocate or reset bitmaps for DF_RD blocks. The solution bits are
+   not touched unless the block is new.  */
+
+static void 
+df_rd_alloc (bitmap all_blocks)
+{
+  unsigned int bb_index;
+  bitmap_iterator bi;
+  struct df_rd_problem_data *problem_data;
+
+  if (!df_rd->block_pool)
+    df_rd->block_pool = create_alloc_pool ("df_rd_block pool", 
+					   sizeof (struct df_rd_bb_info), 50);
+
+  if (df_rd->problem_data)
+    {
+      problem_data = (struct df_rd_problem_data *) df_rd->problem_data;
+      bitmap_clear (problem_data->sparse_invalidated_by_call);
+      bitmap_clear (problem_data->dense_invalidated_by_call);
+    }
+  else 
+    {
+      problem_data = XNEW (struct df_rd_problem_data);
+      df_rd->problem_data = problem_data;
+
+      bitmap_obstack_initialize (&problem_data->rd_bitmaps);
+      problem_data->sparse_invalidated_by_call
+	= BITMAP_ALLOC (&problem_data->rd_bitmaps);
+      problem_data->dense_invalidated_by_call
+	= BITMAP_ALLOC (&problem_data->rd_bitmaps);
+    }
+
+  df_grow_bb_info (df_rd);
+
+  /* Because of the clustering of all use sites for the same pseudo,
+     we have to process all of the blocks before doing the
+     analysis.  */
+
+  EXECUTE_IF_SET_IN_BITMAP (all_blocks, 0, bb_index, bi)
+    {
+      struct df_rd_bb_info *bb_info = df_rd_get_bb_info (bb_index);
+      if (bb_info)
+	{ 
+	  bitmap_clear (bb_info->kill);
+	  bitmap_clear (bb_info->sparse_kill);
+	  bitmap_clear (bb_info->gen);
+	}
+      else
+	{ 
+	  bb_info = (struct df_rd_bb_info *) pool_alloc (df_rd->block_pool);
+	  df_rd_set_bb_info (bb_index, bb_info);
+	  bb_info->kill = BITMAP_ALLOC (&problem_data->rd_bitmaps);
+	  bb_info->sparse_kill = BITMAP_ALLOC (&problem_data->rd_bitmaps);
+	  bb_info->gen = BITMAP_ALLOC (&problem_data->rd_bitmaps);
+	  bb_info->in = BITMAP_ALLOC (&problem_data->rd_bitmaps);
+	  bb_info->out = BITMAP_ALLOC (&problem_data->rd_bitmaps);
+	}
+    }
+  df_rd->optional_p = true;
+}
+
+
+/* Process a list of DEFs for df_rd_bb_local_compute.  */
+
+static void
+df_rd_bb_local_compute_process_def (struct df_rd_bb_info *bb_info, 
+				    df_ref *def_rec,
+				    enum df_ref_flags top_flag)
+{
+  while (*def_rec)
+    {
+      df_ref def = *def_rec;
+      if (top_flag == (DF_REF_FLAGS (def) & DF_REF_AT_TOP))
+	{
+	  unsigned int regno = DF_REF_REGNO (def);
+	  unsigned int begin = DF_DEFS_BEGIN (regno);
+	  unsigned int n_defs = DF_DEFS_COUNT (regno);
+	  
+	  if ((!(df->changeable_flags & DF_NO_HARD_REGS))
+	      || (regno >= FIRST_PSEUDO_REGISTER))
+	    {
+	      /* Only the last def(s) for a regno in the block has any
+		 effect.  */ 
+	      if (!bitmap_bit_p (seen_in_block, regno))
+		{
+		  /* The first def for regno in insn gets to knock out the
+		     defs from other instructions.  */
+		  if ((!bitmap_bit_p (seen_in_insn, regno))
+		      /* If the def is to only part of the reg, it does
+			 not kill the other defs that reach here.  */
+		      && (!(DF_REF_FLAGS (def) & 
+			    (DF_REF_PARTIAL | DF_REF_CONDITIONAL | DF_REF_MAY_CLOBBER))))
+		    {
+		      if (n_defs > DF_SPARSE_THRESHOLD)
+			{
+			  bitmap_set_bit (bb_info->sparse_kill, regno);
+			  bitmap_clear_range(bb_info->gen, begin, n_defs);
+			}
+		      else
+			{
+			  bitmap_set_range (bb_info->kill, begin, n_defs);
+			  bitmap_clear_range (bb_info->gen, begin, n_defs);
+			}
+		    }
+		  
+		  bitmap_set_bit (seen_in_insn, regno);
+		  /* All defs for regno in the instruction may be put into
+		     the gen set.  */
+		  if (!(DF_REF_FLAGS (def) 
+			& (DF_REF_MUST_CLOBBER | DF_REF_MAY_CLOBBER)))
+		    bitmap_set_bit (bb_info->gen, DF_REF_ID (def));
+		}
+	    }
+	}
+      def_rec++;
+    }
+}
+
+/* Compute local reaching def info for basic block BB.  */
+
+static void
+df_rd_bb_local_compute (unsigned int bb_index)
+{
+  basic_block bb = BASIC_BLOCK (bb_index);
+  struct df_rd_bb_info *bb_info = df_rd_get_bb_info (bb_index);
+  rtx insn;
+
+  bitmap_clear (seen_in_block);
+  bitmap_clear (seen_in_insn);
+
+  /* Artificials are only hard regs.  */
+  if (!(df->changeable_flags & DF_NO_HARD_REGS))
+    df_rd_bb_local_compute_process_def (bb_info, 
+					df_get_artificial_defs (bb_index),
+					0);
+
+  FOR_BB_INSNS_REVERSE (bb, insn)
+    {
+      unsigned int uid = INSN_UID (insn);
+
+      if (!INSN_P (insn))
+	continue;
+
+      df_rd_bb_local_compute_process_def (bb_info, 
+					  DF_INSN_UID_DEFS (uid), 0);
+
+      /* This complex dance with the two bitmaps is required because
+	 instructions can assign twice to the same pseudo.  This
+	 generally happens with calls that will have one def for the
+	 result and another def for the clobber.  If only one vector
+	 is used and the clobber goes first, the result will be
+	 lost.  */
+      bitmap_ior_into (seen_in_block, seen_in_insn);
+      bitmap_clear (seen_in_insn);
+    }
+
+  /* Process the artificial defs at the top of the block last since we
+     are going backwards through the block and these are logically at
+     the start.  */
+  if (!(df->changeable_flags & DF_NO_HARD_REGS))
+    df_rd_bb_local_compute_process_def (bb_info, 
+					df_get_artificial_defs (bb_index),
+					DF_REF_AT_TOP);
+}
+
+
+/* Compute local reaching def info for each basic block within BLOCKS.  */
+
+static void
+df_rd_local_compute (bitmap all_blocks)
+{
+  unsigned int bb_index;
+  bitmap_iterator bi;
+  unsigned int regno;
+  struct df_rd_problem_data *problem_data
+    = (struct df_rd_problem_data *) df_rd->problem_data;
+  bitmap sparse_invalidated = problem_data->sparse_invalidated_by_call;
+  bitmap dense_invalidated = problem_data->dense_invalidated_by_call;
+
+  df_set_seen ();
+
+  df_maybe_reorganize_def_refs (DF_REF_ORDER_BY_REG);
+
+  EXECUTE_IF_SET_IN_BITMAP (all_blocks, 0, bb_index, bi)
+    {
+      df_rd_bb_local_compute (bb_index);
+    }
+  
+  /* Set up the knockout bit vectors to be applied across EH_EDGES.  */
+  EXECUTE_IF_SET_IN_BITMAP (regs_invalidated_by_call_regset, 0, regno, bi)
+    {
+      if (DF_DEFS_COUNT (regno) > DF_SPARSE_THRESHOLD)
+	bitmap_set_bit (sparse_invalidated, regno);
+      else
+	bitmap_set_range (dense_invalidated, 
+			  DF_DEFS_BEGIN (regno), 
+			  DF_DEFS_COUNT (regno));
+    }
+  df_unset_seen ();
+}
+
+
+/* Initialize the solution bit vectors for problem.  */
+
+static void 
+df_rd_init_solution (bitmap all_blocks)
+{
+  unsigned int bb_index;
+  bitmap_iterator bi;
+
+  EXECUTE_IF_SET_IN_BITMAP (all_blocks, 0, bb_index, bi)
+    {
+      struct df_rd_bb_info *bb_info = df_rd_get_bb_info (bb_index);
+      
+      bitmap_copy (bb_info->out, bb_info->gen);
+      bitmap_clear (bb_info->in);
+    }
+}
+
+/* In of target gets or of out of source.  */
+
+static void
+df_rd_confluence_n (edge e)
+{
+  bitmap op1 = df_rd_get_bb_info (e->dest->index)->in;
+  bitmap op2 = df_rd_get_bb_info (e->src->index)->out;
+
+  if (e->flags & EDGE_FAKE) 
+    return;
+
+  if (e->flags & EDGE_EH)
+    {
+      struct df_rd_problem_data *problem_data
+	= (struct df_rd_problem_data *) df_rd->problem_data;
+      bitmap sparse_invalidated = problem_data->sparse_invalidated_by_call;
+      bitmap dense_invalidated = problem_data->dense_invalidated_by_call;
+      bitmap_iterator bi;
+      unsigned int regno;
+      bitmap tmp = BITMAP_ALLOC (&df_bitmap_obstack);
+
+      bitmap_copy (tmp, op2);
+      bitmap_and_compl_into (tmp, dense_invalidated);
+
+      EXECUTE_IF_SET_IN_BITMAP (sparse_invalidated, 0, regno, bi)
+ 	{
+ 	  bitmap_clear_range (tmp, 
+ 			      DF_DEFS_BEGIN (regno), 
+ 			      DF_DEFS_COUNT (regno));
+	}
+      bitmap_ior_into (op1, tmp);
+      BITMAP_FREE (tmp);
+    }
+  else
+    bitmap_ior_into (op1, op2);
+}
+
+
+/* Transfer function.  */
+
+static bool
+df_rd_transfer_function (int bb_index)
+{
+  struct df_rd_bb_info *bb_info = df_rd_get_bb_info (bb_index);
+  unsigned int regno;
+  bitmap_iterator bi;
+  bitmap in = bb_info->in;
+  bitmap out = bb_info->out;
+  bitmap gen = bb_info->gen;
+  bitmap kill = bb_info->kill;
+  bitmap sparse_kill = bb_info->sparse_kill;
+
+  if (bitmap_empty_p (sparse_kill))
+    return  bitmap_ior_and_compl (out, gen, in, kill);
+  else 
+    {
+      struct df_rd_problem_data *problem_data;
+      bool changed = false;
+      bitmap tmp;
+
+      /* Note that TMP is _not_ a temporary bitmap if we end up replacing
+	 OUT with TMP.  Therefore, allocate TMP in the RD bitmaps obstack.  */
+      problem_data = (struct df_rd_problem_data *) df_rd->problem_data;
+      tmp = BITMAP_ALLOC (&problem_data->rd_bitmaps);
+
+      bitmap_copy (tmp, in);
+      EXECUTE_IF_SET_IN_BITMAP (sparse_kill, 0, regno, bi)
+	{
+	  bitmap_clear_range (tmp, 
+			      DF_DEFS_BEGIN (regno), 
+			      DF_DEFS_COUNT (regno));
+	}
+      bitmap_and_compl_into (tmp, kill);
+      bitmap_ior_into (tmp, gen);
+      changed = !bitmap_equal_p (tmp, out);
+      if (changed)
+	{
+	  BITMAP_FREE (out);
+	  bb_info->out = tmp;
+	}
+      else 
+	  BITMAP_FREE (tmp);
+      return changed;
+    }
+}
+
+
+/* Free all storage associated with the problem.  */
+
+static void
+df_rd_free (void)
+{
+  struct df_rd_problem_data *problem_data
+    = (struct df_rd_problem_data *) df_rd->problem_data;
+
+  if (problem_data)
+    {
+      free_alloc_pool (df_rd->block_pool);
+      bitmap_obstack_release (&problem_data->rd_bitmaps);
+      
+      df_rd->block_info_size = 0;
+      free (df_rd->block_info);
+      free (df_rd->problem_data);
+    }
+  free (df_rd);
+}
+
+
+/* Debugging info.  */
+
+static void
+df_rd_start_dump (FILE *file)
+{
+  struct df_rd_problem_data *problem_data
+    = (struct df_rd_problem_data *) df_rd->problem_data;
+  unsigned int m = DF_REG_SIZE(df);
+  unsigned int regno;
+  
+  if (!df_rd->block_info) 
+    return;
+
+  fprintf (file, ";; Reaching defs:\n\n");
+
+  fprintf (file, "  sparse invalidated \t");
+  dump_bitmap (file, problem_data->sparse_invalidated_by_call);
+  fprintf (file, "  dense invalidated \t");
+  dump_bitmap (file, problem_data->dense_invalidated_by_call);
+
+  for (regno = 0; regno < m; regno++)
+    if (DF_DEFS_COUNT (regno))
+      fprintf (file, "%d[%d,%d] ", regno, 
+	       DF_DEFS_BEGIN (regno), 
+	       DF_DEFS_COUNT (regno));
+  fprintf (file, "\n");
+
+}
+
+
+/* Debugging info at top of bb.  */
+
+static void
+df_rd_top_dump (basic_block bb, FILE *file)
+{
+  struct df_rd_bb_info *bb_info = df_rd_get_bb_info (bb->index);
+  if (!bb_info || !bb_info->in)
+    return;
+  
+  fprintf (file, ";; rd  in  \t(%d)\n", (int) bitmap_count_bits (bb_info->in));
+  dump_bitmap (file, bb_info->in);
+  fprintf (file, ";; rd  gen \t(%d)\n", (int) bitmap_count_bits (bb_info->gen));
+  dump_bitmap (file, bb_info->gen);
+  fprintf (file, ";; rd  kill\t(%d)\n", (int) bitmap_count_bits (bb_info->kill));
+  dump_bitmap (file, bb_info->kill);
+}
+
+
+/* Debugging info at top of bb.  */
+
+static void
+df_rd_bottom_dump (basic_block bb, FILE *file)
+{
+  struct df_rd_bb_info *bb_info = df_rd_get_bb_info (bb->index);
+  if (!bb_info || !bb_info->out)
+    return;
+  
+  fprintf (file, ";; rd  out \t(%d)\n", (int) bitmap_count_bits (bb_info->out));
+  dump_bitmap (file, bb_info->out);
+}
+
+/* All of the information associated with every instance of the problem.  */
+
+static struct df_problem problem_RD =
+{
+  DF_RD,                      /* Problem id.  */
+  DF_FORWARD,                 /* Direction.  */
+  df_rd_alloc,                /* Allocate the problem specific data.  */
+  NULL,                       /* Reset global information.  */
+  df_rd_free_bb_info,         /* Free basic block info.  */
+  df_rd_local_compute,        /* Local compute function.  */
+  df_rd_init_solution,        /* Init the solution specific data.  */
+  df_worklist_dataflow,       /* Worklist solver.  */
+  NULL,                       /* Confluence operator 0.  */ 
+  df_rd_confluence_n,         /* Confluence operator n.  */ 
+  df_rd_transfer_function,    /* Transfer function.  */
+  NULL,                       /* Finalize function.  */
+  df_rd_free,                 /* Free all of the problem information.  */
+  df_rd_free,                 /* Remove this problem from the stack of dataflow problems.  */
+  df_rd_start_dump,           /* Debugging.  */
+  df_rd_top_dump,             /* Debugging start block.  */
+  df_rd_bottom_dump,          /* Debugging end block.  */
+  NULL,                       /* Incremental solution verify start.  */
+  NULL,                       /* Incremental solution verify end.  */
+  NULL,                       /* Dependent problem.  */
+  TV_DF_RD,                   /* Timing variable.  */ 
+  true                        /* 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_rd_add_problem (void)
+{
+  df_add_problem (&problem_RD);
+}
+
+
+
+/*----------------------------------------------------------------------------
+   LIVE REGISTERS
+
+   Find the locations in the function where any use of a pseudo can
+   reach in the backwards direction.  In and out bitvectors are built
+   for each basic block.  The regno is used to index into these sets.
+   See df.h for details.
+   ----------------------------------------------------------------------------*/
+
+/* Private data used to verify the solution for this problem.  */
+struct df_lr_problem_data
+{
+  bitmap *in;
+  bitmap *out;
+};
+
+
+/* Set basic block info.  */
+
+static void
+df_lr_set_bb_info (unsigned int index, 
+		   struct df_lr_bb_info *bb_info)
+{
+  gcc_assert (df_lr);
+  gcc_assert (index < df_lr->block_info_size);
+  df_lr->block_info[index] = bb_info;
+}
+
+ 
+/* Free basic block info.  */
+
+static void
+df_lr_free_bb_info (basic_block bb ATTRIBUTE_UNUSED, 
+		    void *vbb_info)
+{
+  struct df_lr_bb_info *bb_info = (struct df_lr_bb_info *) vbb_info;
+  if (bb_info)
+    {
+      BITMAP_FREE (bb_info->use);
+      BITMAP_FREE (bb_info->def);
+      BITMAP_FREE (bb_info->in);
+      BITMAP_FREE (bb_info->out);
+      pool_free (df_lr->block_pool, bb_info);
+    }
+}
+
+
+/* Allocate or reset bitmaps for DF_LR blocks. The solution bits are
+   not touched unless the block is new.  */
+
+static void 
+df_lr_alloc (bitmap all_blocks ATTRIBUTE_UNUSED)
+{
+  unsigned int bb_index;
+  bitmap_iterator bi;
+
+  if (!df_lr->block_pool)
+    df_lr->block_pool = create_alloc_pool ("df_lr_block pool", 
+					   sizeof (struct df_lr_bb_info), 50);
+
+  df_grow_bb_info (df_lr);
+
+  EXECUTE_IF_SET_IN_BITMAP (df_lr->out_of_date_transfer_functions, 0, bb_index, bi)
+    {
+      struct df_lr_bb_info *bb_info = df_lr_get_bb_info (bb_index);
+      if (bb_info)
+	{ 
+	  bitmap_clear (bb_info->def);
+	  bitmap_clear (bb_info->use);
+	}
+      else
+	{ 
+	  bb_info = (struct df_lr_bb_info *) pool_alloc (df_lr->block_pool);
+	  df_lr_set_bb_info (bb_index, bb_info);
+	  bb_info->use = BITMAP_ALLOC (NULL);
+	  bb_info->def = BITMAP_ALLOC (NULL);
+	  bb_info->in = BITMAP_ALLOC (NULL);
+	  bb_info->out = BITMAP_ALLOC (NULL);
+	}
+    }
+
+  df_lr->optional_p = false;
+}
+
+
+/* Reset the global solution for recalculation.  */
+
+static void 
+df_lr_reset (bitmap all_blocks)
+{
+  unsigned int bb_index;
+  bitmap_iterator bi;
+
+  EXECUTE_IF_SET_IN_BITMAP (all_blocks, 0, bb_index, bi)
+    {
+      struct df_lr_bb_info *bb_info = df_lr_get_bb_info (bb_index);
+      gcc_assert (bb_info);
+      bitmap_clear (bb_info->in);
+      bitmap_clear (bb_info->out);
+    }
+}
+
+
+/* Compute local live register info for basic block BB.  */
+
+static void
+df_lr_bb_local_compute (unsigned int bb_index)
+{
+  basic_block bb = BASIC_BLOCK (bb_index);
+  struct df_lr_bb_info *bb_info = df_lr_get_bb_info (bb_index);
+  rtx insn;
+  df_ref *def_rec;
+  df_ref *use_rec;
+
+  /* Process the registers set in an exception handler.  */
+  for (def_rec = df_get_artificial_defs (bb_index); *def_rec; def_rec++)
+    {
+      df_ref def = *def_rec;
+      if ((DF_REF_FLAGS (def) & DF_REF_AT_TOP) == 0)
+	{
+	  unsigned int dregno = DF_REF_REGNO (def);
+	  bitmap_set_bit (bb_info->def, dregno);
+	  bitmap_clear_bit (bb_info->use, dregno);
+	}
+    }
+
+  /* Process the hardware registers that are always live.  */
+  for (use_rec = df_get_artificial_uses (bb_index); *use_rec; use_rec++)
+    {
+      df_ref use = *use_rec;
+      /* Add use to set of uses in this BB.  */
+      if ((DF_REF_FLAGS (use) & DF_REF_AT_TOP) == 0)
+	bitmap_set_bit (bb_info->use, DF_REF_REGNO (use));
+    }
+
+  FOR_BB_INSNS_REVERSE (bb, insn)
+    {
+      unsigned int uid = INSN_UID (insn);
+
+      if (!INSN_P (insn))
+	continue;	
+
+      for (def_rec = DF_INSN_UID_DEFS (uid); *def_rec; def_rec++)
+	{
+	  df_ref def = *def_rec;
+	  /* If the def is to only part of the reg, it does
+	     not kill the other defs that reach here.  */
+	  if (!(DF_REF_FLAGS (def) & (DF_REF_PARTIAL | DF_REF_CONDITIONAL)))
+	    {
+	      unsigned int dregno = DF_REF_REGNO (def);
+	      bitmap_set_bit (bb_info->def, dregno);
+	      bitmap_clear_bit (bb_info->use, dregno);
+	    }
+	}
+
+      for (use_rec = DF_INSN_UID_USES (uid); *use_rec; use_rec++)
+	{
+	  df_ref use = *use_rec;
+	  /* Add use to set of uses in this BB.  */
+	  bitmap_set_bit (bb_info->use, DF_REF_REGNO (use));
+	}
+    }
+
+  /* Process the registers set in an exception handler or the hard
+     frame pointer if this block is the target of a non local
+     goto.  */
+  for (def_rec = df_get_artificial_defs (bb_index); *def_rec; def_rec++)
+    {
+      df_ref def = *def_rec;
+      if (DF_REF_FLAGS (def) & DF_REF_AT_TOP)
+	{
+	  unsigned int dregno = DF_REF_REGNO (def);
+	  bitmap_set_bit (bb_info->def, dregno);
+	  bitmap_clear_bit (bb_info->use, dregno);
+	}
+    }
+  
+#ifdef EH_USES
+  /* Process the uses that are live into an exception handler.  */
+  for (use_rec = df_get_artificial_uses (bb_index); *use_rec; use_rec++)
+    {
+      df_ref use = *use_rec;
+      /* Add use to set of uses in this BB.  */
+      if (DF_REF_FLAGS (use) & DF_REF_AT_TOP)
+	bitmap_set_bit (bb_info->use, DF_REF_REGNO (use));
+    }
+#endif
+
+  /* If the df_live problem is not defined, such as at -O0 and -O1, we
+     still need to keep the luids up to date.  This is normally done
+     in the df_live problem since this problem has a forwards
+     scan.  */
+  if (!df_live)
+    df_recompute_luids (bb);
+}
+
+
+/* Compute local live register info for each basic block within BLOCKS.  */
+
+static void
+df_lr_local_compute (bitmap all_blocks ATTRIBUTE_UNUSED)
+{
+  unsigned int bb_index;
+  bitmap_iterator bi;
+    
+  bitmap_clear (df->hardware_regs_used);
+  
+  /* The all-important stack pointer must always be live.  */
+  bitmap_set_bit (df->hardware_regs_used, STACK_POINTER_REGNUM);
+  
+  /* 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.  */
+  if (!reload_completed)
+    {
+      /* Any reference to any pseudo before reload is a potential
+	 reference of the frame pointer.  */
+      bitmap_set_bit (df->hardware_regs_used, FRAME_POINTER_REGNUM);
+      
+#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 (df->hardware_regs_used, ARG_POINTER_REGNUM);
+#endif
+      
+      /* Any constant, or pseudo with constant equivalences, may
+	 require reloading from memory using the pic register.  */
+      if ((unsigned) PIC_OFFSET_TABLE_REGNUM != INVALID_REGNUM
+	  && fixed_regs[PIC_OFFSET_TABLE_REGNUM])
+	bitmap_set_bit (df->hardware_regs_used, PIC_OFFSET_TABLE_REGNUM);
+    }
+  
+  EXECUTE_IF_SET_IN_BITMAP (df_lr->out_of_date_transfer_functions, 0, bb_index, bi)
+    {
+      if (bb_index == EXIT_BLOCK)
+	{
+	  /* The exit block is special for this problem and its bits are
+	     computed from thin air.  */
+	  struct df_lr_bb_info *bb_info = df_lr_get_bb_info (EXIT_BLOCK);
+	  bitmap_copy (bb_info->use, df->exit_block_uses);
+	}
+      else
+	df_lr_bb_local_compute (bb_index);
+    }
+
+  bitmap_clear (df_lr->out_of_date_transfer_functions);
+}
+
+
+/* Initialize the solution vectors.  */
+
+static void 
+df_lr_init (bitmap all_blocks)
+{
+  unsigned int bb_index;
+  bitmap_iterator bi;
+
+  EXECUTE_IF_SET_IN_BITMAP (all_blocks, 0, bb_index, bi)
+    {
+      struct df_lr_bb_info *bb_info = df_lr_get_bb_info (bb_index);
+      bitmap_copy (bb_info->in, bb_info->use);
+      bitmap_clear (bb_info->out);
+    }
+}
+
+
+/* Confluence function that processes infinite loops.  This might be a
+   noreturn function that throws.  And even if it isn't, getting the
+   unwind info right helps debugging.  */
+static void
+df_lr_confluence_0 (basic_block bb)
+{
+  bitmap op1 = df_lr_get_bb_info (bb->index)->out;
+  if (bb != EXIT_BLOCK_PTR)
+    bitmap_copy (op1, df->hardware_regs_used);
+} 
+
+
+/* Confluence function that ignores fake edges.  */
+
+static void
+df_lr_confluence_n (edge e)
+{
+  bitmap op1 = df_lr_get_bb_info (e->src->index)->out;
+  bitmap op2 = df_lr_get_bb_info (e->dest->index)->in;
+ 
+  /* Call-clobbered registers die across exception and call edges.  */
+  /* ??? Abnormal call edges ignored for the moment, as this gets
+     confused by sibling call edges, which crashes reg-stack.  */
+  if (e->flags & EDGE_EH)
+    bitmap_ior_and_compl_into (op1, op2, regs_invalidated_by_call_regset);
+  else
+    bitmap_ior_into (op1, op2);
+
+  bitmap_ior_into (op1, df->hardware_regs_used);
+} 
+
+
+/* Transfer function.  */
+
+static bool
+df_lr_transfer_function (int bb_index)
+{
+  struct df_lr_bb_info *bb_info = df_lr_get_bb_info (bb_index);
+  bitmap in = bb_info->in;
+  bitmap out = bb_info->out;
+  bitmap use = bb_info->use;
+  bitmap def = bb_info->def;
+
+  return bitmap_ior_and_compl (in, use, out, def);
+}
+
+
+/* Run the fast dce as a side effect of building LR.  */
+
+static void
+df_lr_finalize (bitmap all_blocks)
+{
+  df_lr->solutions_dirty = false;
+  if (df->changeable_flags & DF_LR_RUN_DCE)
+    {
+      run_fast_df_dce ();
+
+      /* If dce deletes some instructions, we need to recompute the lr
+	 solution before proceeding further.  The problem is that fast
+	 dce is a pessimestic dataflow algorithm.  In the case where
+	 it deletes a statement S inside of a loop, the uses inside of
+	 S may not be deleted from the dataflow solution because they
+	 were carried around the loop.  While it is conservatively
+	 correct to leave these extra bits, the standards of df
+	 require that we maintain the best possible (least fixed
+	 point) solution.  The only way to do that is to redo the
+	 iteration from the beginning.  See PR35805 for an
+	 example.  */
+      if (df_lr->solutions_dirty)
+	{
+	  df_clear_flags (DF_LR_RUN_DCE);
+	  df_lr_alloc (all_blocks);
+	  df_lr_local_compute (all_blocks);
+	  df_worklist_dataflow (df_lr, all_blocks, df->postorder, df->n_blocks);
+	  df_lr_finalize (all_blocks);
+	  df_set_flags (DF_LR_RUN_DCE);
+	}
+    }
+}
+
+
+/* Free all storage associated with the problem.  */
+
+static void
+df_lr_free (void)
+{
+  if (df_lr->block_info)
+    {
+      unsigned int i;
+      for (i = 0; i < df_lr->block_info_size; i++)
+	{
+	  struct df_lr_bb_info *bb_info = df_lr_get_bb_info (i);
+	  if (bb_info)
+	    {
+	      BITMAP_FREE (bb_info->use);
+	      BITMAP_FREE (bb_info->def);
+	      BITMAP_FREE (bb_info->in);
+	      BITMAP_FREE (bb_info->out);
+	    }
+	}
+      free_alloc_pool (df_lr->block_pool);
+      
+      df_lr->block_info_size = 0;
+      free (df_lr->block_info);
+    }
+
+  BITMAP_FREE (df_lr->out_of_date_transfer_functions);
+  free (df_lr);
+}
+
+
+/* Debugging info at top of bb.  */
+
+static void
+df_lr_top_dump (basic_block bb, FILE *file)
+{
+  struct df_lr_bb_info *bb_info = df_lr_get_bb_info (bb->index);
+  struct df_lr_problem_data *problem_data;
+  if (!bb_info || !bb_info->in)
+    return;
+      
+  fprintf (file, ";; lr  in  \t");
+  df_print_regset (file, bb_info->in);
+  if (df_lr->problem_data)
+    {
+      problem_data = (struct df_lr_problem_data *)df_lr->problem_data;
+      fprintf (file, ";;  old in  \t");
+      df_print_regset (file, problem_data->in[bb->index]);
+    }
+  fprintf (file, ";; lr  use \t");
+  df_print_regset (file, bb_info->use);
+  fprintf (file, ";; lr  def \t");
+  df_print_regset (file, bb_info->def);
+}  
+
+
+/* Debugging info at bottom of bb.  */
+
+static void
+df_lr_bottom_dump (basic_block bb, FILE *file)
+{
+  struct df_lr_bb_info *bb_info = df_lr_get_bb_info (bb->index);
+  struct df_lr_problem_data *problem_data;
+  if (!bb_info || !bb_info->out)
+    return;
+  
+  fprintf (file, ";; lr  out \t");
+  df_print_regset (file, bb_info->out);
+  if (df_lr->problem_data)
+    {
+      problem_data = (struct df_lr_problem_data *)df_lr->problem_data;
+      fprintf (file, ";;  old out  \t");
+      df_print_regset (file, problem_data->out[bb->index]);
+    }
+}  
+
+
+/* Build the datastructure to verify that the solution to the dataflow
+   equations is not dirty.  */
+
+static void
+df_lr_verify_solution_start (void)
+{
+  basic_block bb;
+  struct df_lr_problem_data *problem_data;
+  if (df_lr->solutions_dirty)
+    {
+      df_lr->problem_data = NULL;
+      return;
+    }
+
+  /* Set it true so that the solution is recomputed.  */ 
+  df_lr->solutions_dirty = true;
+
+  problem_data = XNEW (struct df_lr_problem_data);
+  df_lr->problem_data = problem_data;
+  problem_data->in = XNEWVEC (bitmap, last_basic_block);
+  problem_data->out = XNEWVEC (bitmap, last_basic_block);
+
+  FOR_ALL_BB (bb)
+    {
+      problem_data->in[bb->index] = BITMAP_ALLOC (NULL);
+      problem_data->out[bb->index] = BITMAP_ALLOC (NULL);
+      bitmap_copy (problem_data->in[bb->index], DF_LR_IN (bb));
+      bitmap_copy (problem_data->out[bb->index], DF_LR_OUT (bb));
+    }
+}
+
+
+/* Compare the saved datastructure and the new solution to the dataflow
+   equations.  */
+
+static void
+df_lr_verify_solution_end (void)
+{
+  struct df_lr_problem_data *problem_data;
+  basic_block bb;
+
+  if (df_lr->problem_data == NULL)
+    return;
+
+  problem_data = (struct df_lr_problem_data *)df_lr->problem_data;
+
+  if (df_lr->solutions_dirty)
+    /* Do not check if the solution is still dirty.  See the comment
+       in df_lr_finalize for details.  */
+    df_lr->solutions_dirty = false;
+  else
+    FOR_ALL_BB (bb)
+      {
+	if ((!bitmap_equal_p (problem_data->in[bb->index], DF_LR_IN (bb)))
+	    || (!bitmap_equal_p (problem_data->out[bb->index], DF_LR_OUT (bb))))
+	  {
+	    /*df_dump (stderr);*/
+	    gcc_unreachable ();
+	  }
+      }
+
+  /* Cannot delete them immediately because you may want to dump them
+     if the comparison fails.  */
+  FOR_ALL_BB (bb)
+    {
+      BITMAP_FREE (problem_data->in[bb->index]);
+      BITMAP_FREE (problem_data->out[bb->index]);
+    }
+
+  free (problem_data->in);
+  free (problem_data->out);
+  free (problem_data);
+  df_lr->problem_data = NULL;
+}
+
+
+/* All of the information associated with every instance of the problem.  */
+
+static struct df_problem problem_LR =
+{
+  DF_LR,                      /* Problem id.  */
+  DF_BACKWARD,                /* Direction.  */
+  df_lr_alloc,                /* Allocate the problem specific data.  */
+  df_lr_reset,                /* Reset global information.  */
+  df_lr_free_bb_info,         /* Free basic block info.  */
+  df_lr_local_compute,        /* Local compute function.  */
+  df_lr_init,                 /* Init the solution specific data.  */
+  df_worklist_dataflow,       /* Worklist solver.  */
+  df_lr_confluence_0,         /* Confluence operator 0.  */ 
+  df_lr_confluence_n,         /* Confluence operator n.  */ 
+  df_lr_transfer_function,    /* Transfer function.  */
+  df_lr_finalize,             /* Finalize function.  */
+  df_lr_free,                 /* Free all of the problem information.  */
+  NULL,                       /* Remove this problem from the stack of dataflow problems.  */
+  NULL,                       /* Debugging.  */
+  df_lr_top_dump,             /* Debugging start block.  */
+  df_lr_bottom_dump,          /* Debugging end block.  */
+  df_lr_verify_solution_start,/* Incremental solution verify start.  */
+  df_lr_verify_solution_end,  /* Incremental solution verify end.  */
+  NULL,                       /* Dependent problem.  */
+  TV_DF_LR,                   /* 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_lr_add_problem (void)
+{
+  df_add_problem (&problem_LR);
+  /* These will be initialized when df_scan_blocks processes each
+     block.  */
+  df_lr->out_of_date_transfer_functions = BITMAP_ALLOC (NULL);
+}
+
+
+/* Verify that all of the lr related info is consistent and
+   correct.  */
+
+void
+df_lr_verify_transfer_functions (void)
+{
+  basic_block bb;
+  bitmap saved_def;
+  bitmap saved_use;
+  bitmap saved_adef;
+  bitmap saved_ause;
+  bitmap all_blocks;
+
+  if (!df)
+    return;
+
+  saved_def = BITMAP_ALLOC (NULL);
+  saved_use = BITMAP_ALLOC (NULL);
+  saved_adef = BITMAP_ALLOC (NULL);
+  saved_ause = BITMAP_ALLOC (NULL);
+  all_blocks = BITMAP_ALLOC (NULL);
+
+  FOR_ALL_BB (bb)
+    {
+      struct df_lr_bb_info *bb_info = df_lr_get_bb_info (bb->index);
+      bitmap_set_bit (all_blocks, bb->index);
+
+      if (bb_info)
+	{
+	  /* Make a copy of the transfer functions and then compute
+	     new ones to see if the transfer functions have
+	     changed.  */
+	  if (!bitmap_bit_p (df_lr->out_of_date_transfer_functions, 
+			     bb->index))
+	    {
+	      bitmap_copy (saved_def, bb_info->def);
+	      bitmap_copy (saved_use, bb_info->use);
+	      bitmap_clear (bb_info->def);
+	      bitmap_clear (bb_info->use);
+
+	      df_lr_bb_local_compute (bb->index);
+	      gcc_assert (bitmap_equal_p (saved_def, bb_info->def));
+	      gcc_assert (bitmap_equal_p (saved_use, bb_info->use));
+	    }
+	}
+      else
+	{
+	  /* If we do not have basic block info, the block must be in
+	     the list of dirty blocks or else some one has added a
+	     block behind our backs. */
+	  gcc_assert (bitmap_bit_p (df_lr->out_of_date_transfer_functions, 
+				    bb->index));
+	}
+      /* Make sure no one created a block without following
+	 procedures.  */
+      gcc_assert (df_scan_get_bb_info (bb->index));
+    }
+
+  /* Make sure there are no dirty bits in blocks that have been deleted.  */
+  gcc_assert (!bitmap_intersect_compl_p (df_lr->out_of_date_transfer_functions, 
+					 all_blocks)); 
+
+  BITMAP_FREE (saved_def);
+  BITMAP_FREE (saved_use);
+  BITMAP_FREE (saved_adef);
+  BITMAP_FREE (saved_ause);
+  BITMAP_FREE (all_blocks);
+}
+
+
+
+/*----------------------------------------------------------------------------
+   LIVE AND MUST-INITIALIZED REGISTERS.
+
+   This problem first computes the IN and OUT bitvectors for the
+   must-initialized registers problems, which is a forward problem.
+   It gives the set of registers for which we MUST have an available
+   definition on any path from the entry block to the entry/exit of
+   a basic block.  Sets generate a definition, while clobbers kill
+   a definition.
+
+   In and out bitvectors are built for each basic block and are indexed by
+   regnum (see df.h for details).  In and out bitvectors in struct
+   df_live_bb_info actually refers to the must-initialized problem;
+
+   Then, the in and out sets for the LIVE problem itself are computed.
+   These are the logical AND of the IN and OUT sets from the LR problem
+   and the must-initialized problem. 
+----------------------------------------------------------------------------*/
+
+/* Private data used to verify the solution for this problem.  */
+struct df_live_problem_data
+{
+  bitmap *in;
+  bitmap *out;
+};
+
+/* Scratch var used by transfer functions.  This is used to implement
+   an optimization to reduce the amount of space used to compute the
+   combined lr and live analysis.  */
+static bitmap df_live_scratch;
+
+/* Set basic block info.  */
+
+static void
+df_live_set_bb_info (unsigned int index, 
+		   struct df_live_bb_info *bb_info)
+{
+  gcc_assert (df_live);
+  gcc_assert (index < df_live->block_info_size);
+  df_live->block_info[index] = bb_info;
+}
+
+
+/* Free basic block info.  */
+
+static void
+df_live_free_bb_info (basic_block bb ATTRIBUTE_UNUSED, 
+		    void *vbb_info)
+{
+  struct df_live_bb_info *bb_info = (struct df_live_bb_info *) vbb_info;
+  if (bb_info)
+    {
+      BITMAP_FREE (bb_info->gen);
+      BITMAP_FREE (bb_info->kill);
+      BITMAP_FREE (bb_info->in);
+      BITMAP_FREE (bb_info->out);
+      pool_free (df_live->block_pool, bb_info);
+    }
+}
+
+
+/* Allocate or reset bitmaps for DF_LIVE blocks. The solution bits are
+   not touched unless the block is new.  */
+
+static void 
+df_live_alloc (bitmap all_blocks ATTRIBUTE_UNUSED)
+{
+  unsigned int bb_index;
+  bitmap_iterator bi;
+
+  if (!df_live->block_pool)
+    df_live->block_pool = create_alloc_pool ("df_live_block pool", 
+					   sizeof (struct df_live_bb_info), 100);
+  if (!df_live_scratch)
+    df_live_scratch = BITMAP_ALLOC (NULL);
+
+  df_grow_bb_info (df_live);
+
+  EXECUTE_IF_SET_IN_BITMAP (df_live->out_of_date_transfer_functions, 0, bb_index, bi)
+    {
+      struct df_live_bb_info *bb_info = df_live_get_bb_info (bb_index);
+      if (bb_info)
+	{ 
+	  bitmap_clear (bb_info->kill);
+	  bitmap_clear (bb_info->gen);
+	}
+      else
+	{ 
+	  bb_info = (struct df_live_bb_info *) pool_alloc (df_live->block_pool);
+	  df_live_set_bb_info (bb_index, bb_info);
+	  bb_info->kill = BITMAP_ALLOC (NULL);
+	  bb_info->gen = BITMAP_ALLOC (NULL);
+	  bb_info->in = BITMAP_ALLOC (NULL);
+	  bb_info->out = BITMAP_ALLOC (NULL);
+	}
+    }
+  df_live->optional_p = (optimize <= 1);
+}
+
+
+/* Reset the global solution for recalculation.  */
+
+static void 
+df_live_reset (bitmap all_blocks)
+{
+  unsigned int bb_index;
+  bitmap_iterator bi;
+
+  EXECUTE_IF_SET_IN_BITMAP (all_blocks, 0, bb_index, bi)
+    {
+      struct df_live_bb_info *bb_info = df_live_get_bb_info (bb_index);
+      gcc_assert (bb_info);
+      bitmap_clear (bb_info->in);
+      bitmap_clear (bb_info->out);
+    }
+}
+
+
+/* Compute local uninitialized register info for basic block BB.  */
+
+static void
+df_live_bb_local_compute (unsigned int bb_index)
+{
+  basic_block bb = BASIC_BLOCK (bb_index);
+  struct df_live_bb_info *bb_info = df_live_get_bb_info (bb_index);
+  rtx insn;
+  df_ref *def_rec;
+  int luid = 0;
+
+  FOR_BB_INSNS (bb, insn)
+    {
+      unsigned int uid = INSN_UID (insn);
+      struct df_insn_info *insn_info = DF_INSN_UID_GET (uid);
+
+      /* 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))
+	continue;
+
+      luid++;
+      for (def_rec = DF_INSN_INFO_DEFS (insn_info); *def_rec; def_rec++)
+	{
+	  df_ref def = *def_rec;
+	  unsigned int regno = DF_REF_REGNO (def);
+
+	  if (DF_REF_FLAGS_IS_SET (def,
+				   DF_REF_PARTIAL | DF_REF_CONDITIONAL))
+	    /* All partial or conditional def
+	       seen are included in the gen set. */
+	    bitmap_set_bit (bb_info->gen, regno);
+	  else if (DF_REF_FLAGS_IS_SET (def, DF_REF_MUST_CLOBBER))
+	    /* Only must clobbers for the entire reg destroy the
+	       value.  */
+	    bitmap_set_bit (bb_info->kill, regno);
+	  else if (! DF_REF_FLAGS_IS_SET (def, DF_REF_MAY_CLOBBER))
+	    bitmap_set_bit (bb_info->gen, regno);
+	}
+    }
+
+  for (def_rec = df_get_artificial_defs (bb_index); *def_rec; def_rec++)
+    {
+      df_ref def = *def_rec;
+      bitmap_set_bit (bb_info->gen, DF_REF_REGNO (def));
+    }
+}
+
+
+/* Compute local uninitialized register info.  */
+
+static void
+df_live_local_compute (bitmap all_blocks ATTRIBUTE_UNUSED)
+{
+  unsigned int bb_index;
+  bitmap_iterator bi;
+
+  df_grow_insn_info ();
+
+  EXECUTE_IF_SET_IN_BITMAP (df_live->out_of_date_transfer_functions, 
+			    0, bb_index, bi)
+    {
+      df_live_bb_local_compute (bb_index);
+    }
+
+  bitmap_clear (df_live->out_of_date_transfer_functions);
+}
+
+
+/* Initialize the solution vectors.  */
+
+static void 
+df_live_init (bitmap all_blocks)
+{
+  unsigned int bb_index;
+  bitmap_iterator bi;
+
+  EXECUTE_IF_SET_IN_BITMAP (all_blocks, 0, bb_index, bi)
+    {
+      struct df_live_bb_info *bb_info = df_live_get_bb_info (bb_index);
+      struct df_lr_bb_info *bb_lr_info = df_lr_get_bb_info (bb_index);
+
+      /* No register may reach a location where it is not used.  Thus
+	 we trim the rr result to the places where it is used.  */
+      bitmap_and (bb_info->out, bb_info->gen, bb_lr_info->out);
+      bitmap_clear (bb_info->in);
+    }
+}
+
+/* Forward confluence function that ignores fake edges.  */
+
+static void
+df_live_confluence_n (edge e)
+{
+  bitmap op1 = df_live_get_bb_info (e->dest->index)->in;
+  bitmap op2 = df_live_get_bb_info (e->src->index)->out;
+ 
+  if (e->flags & EDGE_FAKE) 
+    return;
+
+  bitmap_ior_into (op1, op2);
+} 
+
+
+/* Transfer function for the forwards must-initialized problem.  */
+
+static bool
+df_live_transfer_function (int bb_index)
+{
+  struct df_live_bb_info *bb_info = df_live_get_bb_info (bb_index);
+  struct df_lr_bb_info *bb_lr_info = df_lr_get_bb_info (bb_index);
+  bitmap in = bb_info->in;
+  bitmap out = bb_info->out;
+  bitmap gen = bb_info->gen;
+  bitmap kill = bb_info->kill;
+
+  /* We need to use a scratch set here so that the value returned from
+     this function invocation properly reflects if the sets changed in
+     a significant way; i.e. not just because the lr set was anded
+     in.  */
+  bitmap_and (df_live_scratch, gen, bb_lr_info->out);
+  /* No register may reach a location where it is not used.  Thus
+     we trim the rr result to the places where it is used.  */
+  bitmap_and_into (in, bb_lr_info->in);
+
+  return bitmap_ior_and_compl (out, df_live_scratch, in, kill);
+}
+
+
+/* And the LR info with the must-initialized registers, to produce the LIVE info.  */
+
+static void
+df_live_finalize (bitmap all_blocks)
+{
+
+  if (df_live->solutions_dirty)
+    {
+      bitmap_iterator bi;
+      unsigned int bb_index;
+
+      EXECUTE_IF_SET_IN_BITMAP (all_blocks, 0, bb_index, bi)
+	{
+	  struct df_lr_bb_info *bb_lr_info = df_lr_get_bb_info (bb_index);
+	  struct df_live_bb_info *bb_live_info = df_live_get_bb_info (bb_index);
+  
+	  /* No register may reach a location where it is not used.  Thus
+	     we trim the rr result to the places where it is used.  */
+	  bitmap_and_into (bb_live_info->in, bb_lr_info->in);
+	  bitmap_and_into (bb_live_info->out, bb_lr_info->out);
+	}
+      
+      df_live->solutions_dirty = false;
+    }
+}
+
+
+/* Free all storage associated with the problem.  */
+
+static void
+df_live_free (void)
+{
+  if (df_live->block_info)
+    {
+      unsigned int i;
+      
+      for (i = 0; i < df_live->block_info_size; i++)
+	{
+	  struct df_live_bb_info *bb_info = df_live_get_bb_info (i);
+	  if (bb_info)
+	    {
+	      BITMAP_FREE (bb_info->gen);
+	      BITMAP_FREE (bb_info->kill);
+	      BITMAP_FREE (bb_info->in);
+	      BITMAP_FREE (bb_info->out);
+	    }
+	}
+      
+      free_alloc_pool (df_live->block_pool);
+      df_live->block_info_size = 0;
+      free (df_live->block_info);
+
+      if (df_live_scratch)
+	BITMAP_FREE (df_live_scratch);
+    }
+  BITMAP_FREE (df_live->out_of_date_transfer_functions);
+  free (df_live);
+}
+
+
+/* Debugging info at top of bb.  */
+
+static void
+df_live_top_dump (basic_block bb, FILE *file)
+{
+  struct df_live_bb_info *bb_info = df_live_get_bb_info (bb->index);
+  struct df_live_problem_data *problem_data;
+
+  if (!bb_info || !bb_info->in)
+    return;
+      
+  fprintf (file, ";; live  in  \t");
+  df_print_regset (file, bb_info->in);
+  if (df_live->problem_data)
+    {
+      problem_data = (struct df_live_problem_data *)df_live->problem_data;
+      fprintf (file, ";;  old in  \t");
+      df_print_regset (file, problem_data->in[bb->index]);
+    }
+  fprintf (file, ";; live  gen \t");
+  df_print_regset (file, bb_info->gen);
+  fprintf (file, ";; live  kill\t");
+  df_print_regset (file, bb_info->kill);
+}
+
+
+/* Debugging info at bottom of bb.  */
+
+static void
+df_live_bottom_dump (basic_block bb, FILE *file)
+{
+  struct df_live_bb_info *bb_info = df_live_get_bb_info (bb->index);
+  struct df_live_problem_data *problem_data;
+
+  if (!bb_info || !bb_info->out)
+    return;
+      
+  fprintf (file, ";; live  out \t");
+  df_print_regset (file, bb_info->out);
+  if (df_live->problem_data)
+    {
+      problem_data = (struct df_live_problem_data *)df_live->problem_data;
+      fprintf (file, ";;  old out  \t");
+      df_print_regset (file, problem_data->out[bb->index]);
+    }
+}
+
+
+/* Build the datastructure to verify that the solution to the dataflow
+   equations is not dirty.  */
+
+static void
+df_live_verify_solution_start (void)
+{
+  basic_block bb;
+  struct df_live_problem_data *problem_data;
+  if (df_live->solutions_dirty)
+    {
+      df_live->problem_data = NULL;
+      return;
+    }
+
+  /* Set it true so that the solution is recomputed.  */ 
+  df_live->solutions_dirty = true;
+
+  problem_data = XNEW (struct df_live_problem_data);
+  df_live->problem_data = problem_data;
+  problem_data->in = XNEWVEC (bitmap, last_basic_block);
+  problem_data->out = XNEWVEC (bitmap, last_basic_block);
+
+  FOR_ALL_BB (bb)
+    {
+      problem_data->in[bb->index] = BITMAP_ALLOC (NULL);
+      problem_data->out[bb->index] = BITMAP_ALLOC (NULL);
+      bitmap_copy (problem_data->in[bb->index], DF_LIVE_IN (bb));
+      bitmap_copy (problem_data->out[bb->index], DF_LIVE_OUT (bb));
+    }
+}
+
+
+/* Compare the saved datastructure and the new solution to the dataflow
+   equations.  */
+
+static void
+df_live_verify_solution_end (void)
+{
+  struct df_live_problem_data *problem_data;
+  basic_block bb;
+
+  if (df_live->problem_data == NULL)
+    return;
+
+  problem_data = (struct df_live_problem_data *)df_live->problem_data;
+
+  FOR_ALL_BB (bb)
+    {
+      if ((!bitmap_equal_p (problem_data->in[bb->index], DF_LIVE_IN (bb)))
+	  || (!bitmap_equal_p (problem_data->out[bb->index], DF_LIVE_OUT (bb))))
+	{
+	  /*df_dump (stderr);*/
+	  gcc_unreachable ();
+	}
+    }
+
+  /* Cannot delete them immediately because you may want to dump them
+     if the comparison fails.  */
+  FOR_ALL_BB (bb)
+    {
+      BITMAP_FREE (problem_data->in[bb->index]);
+      BITMAP_FREE (problem_data->out[bb->index]);
+    }
+
+  free (problem_data->in);
+  free (problem_data->out);
+  free (problem_data);
+  df_live->problem_data = NULL;
+}
+
+
+/* All of the information associated with every instance of the problem.  */
+
+static struct df_problem problem_LIVE =
+{
+  DF_LIVE,                      /* Problem id.  */
+  DF_FORWARD,                   /* Direction.  */
+  df_live_alloc,                /* Allocate the problem specific data.  */
+  df_live_reset,                /* Reset global information.  */
+  df_live_free_bb_info,         /* Free basic block info.  */
+  df_live_local_compute,        /* Local compute function.  */
+  df_live_init,                 /* Init the solution specific data.  */
+  df_worklist_dataflow,         /* Worklist solver.  */
+  NULL,                         /* Confluence operator 0.  */ 
+  df_live_confluence_n,         /* Confluence operator n.  */ 
+  df_live_transfer_function,    /* Transfer function.  */
+  df_live_finalize,             /* Finalize function.  */
+  df_live_free,                 /* Free all of the problem information.  */
+  df_live_free,                 /* Remove this problem from the stack of dataflow problems.  */
+  NULL,                         /* Debugging.  */
+  df_live_top_dump,             /* Debugging start block.  */
+  df_live_bottom_dump,          /* Debugging end block.  */
+  df_live_verify_solution_start,/* Incremental solution verify start.  */
+  df_live_verify_solution_end,  /* Incremental solution verify end.  */
+  &problem_LR,                  /* Dependent problem.  */
+  TV_DF_LIVE,                   /* 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_live_add_problem (void)
+{
+  df_add_problem (&problem_LIVE);
+  /* These will be initialized when df_scan_blocks processes each
+     block.  */
+  df_live->out_of_date_transfer_functions = BITMAP_ALLOC (NULL);
+}
+
+
+/* Set all of the blocks as dirty.  This needs to be done if this
+   problem is added after all of the insns have been scanned.  */
+
+void
+df_live_set_all_dirty (void)
+{
+  basic_block bb;
+  FOR_ALL_BB (bb)
+    bitmap_set_bit (df_live->out_of_date_transfer_functions, 
+		    bb->index);
+}
+
+
+/* Verify that all of the lr related info is consistent and
+   correct.  */
+
+void
+df_live_verify_transfer_functions (void)
+{
+  basic_block bb;
+  bitmap saved_gen;
+  bitmap saved_kill;
+  bitmap all_blocks;
+
+  if (!df)
+    return;
+
+  saved_gen = BITMAP_ALLOC (NULL);
+  saved_kill = BITMAP_ALLOC (NULL);
+  all_blocks = BITMAP_ALLOC (NULL);
+
+  df_grow_insn_info ();
+
+  FOR_ALL_BB (bb)
+    {
+      struct df_live_bb_info *bb_info = df_live_get_bb_info (bb->index);
+      bitmap_set_bit (all_blocks, bb->index);
+
+      if (bb_info)
+	{
+	  /* Make a copy of the transfer functions and then compute
+	     new ones to see if the transfer functions have
+	     changed.  */
+	  if (!bitmap_bit_p (df_live->out_of_date_transfer_functions, 
+			     bb->index))
+	    {
+	      bitmap_copy (saved_gen, bb_info->gen);
+	      bitmap_copy (saved_kill, bb_info->kill);
+	      bitmap_clear (bb_info->gen);
+	      bitmap_clear (bb_info->kill);
+
+	      df_live_bb_local_compute (bb->index);
+	      gcc_assert (bitmap_equal_p (saved_gen, bb_info->gen));
+	      gcc_assert (bitmap_equal_p (saved_kill, bb_info->kill));
+	    }
+	}
+      else
+	{
+	  /* If we do not have basic block info, the block must be in
+	     the list of dirty blocks or else some one has added a
+	     block behind our backs. */
+	  gcc_assert (bitmap_bit_p (df_live->out_of_date_transfer_functions, 
+				    bb->index));
+	}
+      /* Make sure no one created a block without following
+	 procedures.  */
+      gcc_assert (df_scan_get_bb_info (bb->index));
+    }
+
+  /* Make sure there are no dirty bits in blocks that have been deleted.  */
+  gcc_assert (!bitmap_intersect_compl_p (df_live->out_of_date_transfer_functions, 
+					 all_blocks)); 
+  BITMAP_FREE (saved_gen);
+  BITMAP_FREE (saved_kill);
+  BITMAP_FREE (all_blocks);
+}
+
+/*----------------------------------------------------------------------------
+   CREATE DEF_USE (DU) and / or USE_DEF (UD) CHAINS
+
+   Link either the defs to the uses and / or the uses to the defs.
+
+   These problems are set up like the other dataflow problems so that
+   they nicely fit into the framework.  They are much simpler and only
+   involve a single traversal of instructions and an examination of
+   the reaching defs information (the dependent problem).
+----------------------------------------------------------------------------*/
+
+#define df_chain_problem_p(FLAG) (((enum df_chain_flags)df_chain->local_flags)&(FLAG))
+
+/* Create a du or ud chain from SRC to DST and link it into SRC.   */
+
+struct df_link *
+df_chain_create (df_ref src, df_ref dst)
+{
+  struct df_link *head = DF_REF_CHAIN (src);
+  struct df_link *link = (struct df_link *) pool_alloc (df_chain->block_pool);
+  
+  DF_REF_CHAIN (src) = link;
+  link->next = head;
+  link->ref = dst;
+  return link;
+}
+
+
+/* Delete any du or ud chains that start at REF and point to
+   TARGET.  */ 
+static void
+df_chain_unlink_1 (df_ref ref, df_ref target)
+{
+  struct df_link *chain = DF_REF_CHAIN (ref);
+  struct df_link *prev = NULL;
+
+  while (chain)
+    {
+      if (chain->ref == target)
+	{
+	  if (prev)
+	    prev->next = chain->next;
+	  else
+	    DF_REF_CHAIN (ref) = chain->next;
+	  pool_free (df_chain->block_pool, chain);
+	  return;
+	}
+      prev = chain;
+      chain = chain->next;
+    }
+}
+
+
+/* Delete a du or ud chain that leave or point to REF.  */
+
+void
+df_chain_unlink (df_ref ref)
+{
+  struct df_link *chain = DF_REF_CHAIN (ref);
+  while (chain)
+    {
+      struct df_link *next = chain->next;
+      /* Delete the other side if it exists.  */
+      df_chain_unlink_1 (chain->ref, ref);
+      pool_free (df_chain->block_pool, chain);
+      chain = next;
+    }
+  DF_REF_CHAIN (ref) = NULL;
+}
+
+
+/* Copy the du or ud chain starting at FROM_REF and attach it to
+   TO_REF.  */ 
+
+void 
+df_chain_copy (df_ref to_ref, 
+	       struct df_link *from_ref)
+{
+  while (from_ref)
+    {
+      df_chain_create (to_ref, from_ref->ref);
+      from_ref = from_ref->next;
+    }
+}
+
+
+/* Remove this problem from the stack of dataflow problems.  */
+
+static void
+df_chain_remove_problem (void)
+{
+  bitmap_iterator bi;
+  unsigned int bb_index;
+
+  /* Wholesale destruction of the old chains.  */ 
+  if (df_chain->block_pool)
+    free_alloc_pool (df_chain->block_pool);
+
+  EXECUTE_IF_SET_IN_BITMAP (df_chain->out_of_date_transfer_functions, 0, bb_index, bi)
+    {
+      rtx insn;
+      df_ref *def_rec;
+      df_ref *use_rec;
+      basic_block bb = BASIC_BLOCK (bb_index);
+
+      if (df_chain_problem_p (DF_DU_CHAIN))
+	for (def_rec = df_get_artificial_defs (bb->index); *def_rec; def_rec++)
+	  DF_REF_CHAIN (*def_rec) = NULL;
+      if (df_chain_problem_p (DF_UD_CHAIN))
+	for (use_rec = df_get_artificial_uses (bb->index); *use_rec; use_rec++)
+	  DF_REF_CHAIN (*use_rec) = NULL;
+      
+      FOR_BB_INSNS (bb, insn)
+	{
+	  unsigned int uid = INSN_UID (insn);
+	  
+	  if (INSN_P (insn))
+	    {
+	      if (df_chain_problem_p (DF_DU_CHAIN))
+		for (def_rec = DF_INSN_UID_DEFS (uid); *def_rec; def_rec++)
+		  DF_REF_CHAIN (*def_rec) = NULL;
+	      if (df_chain_problem_p (DF_UD_CHAIN))
+		{
+		  for (use_rec = DF_INSN_UID_USES (uid); *use_rec; use_rec++)
+		    DF_REF_CHAIN (*use_rec) = NULL;
+		  for (use_rec = DF_INSN_UID_EQ_USES (uid); *use_rec; use_rec++)
+		    DF_REF_CHAIN (*use_rec) = NULL;
+		}
+	    }
+	}
+    }
+
+  bitmap_clear (df_chain->out_of_date_transfer_functions);
+  df_chain->block_pool = NULL;
+}
+
+
+/* Remove the chain problem completely.  */
+
+static void
+df_chain_fully_remove_problem (void)
+{
+  df_chain_remove_problem ();
+  BITMAP_FREE (df_chain->out_of_date_transfer_functions);
+  free (df_chain);
+}
+
+
+/* Create def-use or use-def chains.  */
+
+static void  
+df_chain_alloc (bitmap all_blocks ATTRIBUTE_UNUSED)
+{
+  df_chain_remove_problem ();
+  df_chain->block_pool = create_alloc_pool ("df_chain_block pool", 
+					 sizeof (struct df_link), 50);
+  df_chain->optional_p = true;
+}
+
+
+/* Reset all of the chains when the set of basic blocks changes.  */
+
+static void
+df_chain_reset (bitmap blocks_to_clear ATTRIBUTE_UNUSED)
+{
+  df_chain_remove_problem ();
+}
+
+
+/* Create the chains for a list of USEs.  */
+
+static void
+df_chain_create_bb_process_use (bitmap local_rd,
+				df_ref *use_rec,
+				enum df_ref_flags top_flag)
+{
+  bitmap_iterator bi;
+  unsigned int def_index;
+  
+  while (*use_rec)
+    {
+      df_ref use = *use_rec;
+      unsigned int uregno = DF_REF_REGNO (use);
+      if ((!(df->changeable_flags & DF_NO_HARD_REGS))
+	  || (uregno >= FIRST_PSEUDO_REGISTER))
+	{
+	  /* Do not want to go through this for an uninitialized var.  */
+	  int count = DF_DEFS_COUNT (uregno);
+	  if (count)
+	    {
+	      if (top_flag == (DF_REF_FLAGS (use) & DF_REF_AT_TOP))
+		{
+		  unsigned int first_index = DF_DEFS_BEGIN (uregno);
+		  unsigned int last_index = first_index + count - 1;
+		  
+		  EXECUTE_IF_SET_IN_BITMAP (local_rd, first_index, def_index, bi)
+		    {
+		      df_ref def;
+		      if (def_index > last_index) 
+			break;
+		      
+		      def = DF_DEFS_GET (def_index);
+		      if (df_chain_problem_p (DF_DU_CHAIN))
+			df_chain_create (def, use);
+		      if (df_chain_problem_p (DF_UD_CHAIN))
+			df_chain_create (use, def);
+		    }
+		}
+	    }
+	}
+
+      use_rec++;
+    }
+}
+
+
+/* Create chains from reaching defs bitmaps for basic block BB.  */
+
+static void
+df_chain_create_bb (unsigned int bb_index)
+{
+  basic_block bb = BASIC_BLOCK (bb_index);
+  struct df_rd_bb_info *bb_info = df_rd_get_bb_info (bb_index);
+  rtx insn;
+  bitmap cpy = BITMAP_ALLOC (NULL);
+  df_ref *def_rec;
+
+  bitmap_copy (cpy, bb_info->in);
+  bitmap_set_bit (df_chain->out_of_date_transfer_functions, bb_index);
+
+  /* Since we are going forwards, process the artificial uses first
+     then the artificial defs second.  */
+
+#ifdef EH_USES
+  /* Create the chains for the artificial uses from the EH_USES at the
+     beginning of the block.  */
+  
+  /* Artificials are only hard regs.  */
+  if (!(df->changeable_flags & DF_NO_HARD_REGS))
+    df_chain_create_bb_process_use (cpy,
+				    df_get_artificial_uses (bb->index), 
+				    DF_REF_AT_TOP);
+#endif
+
+  for (def_rec = df_get_artificial_defs (bb_index); *def_rec; def_rec++)
+    {
+      df_ref def = *def_rec;
+      if (DF_REF_FLAGS (def) & DF_REF_AT_TOP)
+	{
+	  unsigned int dregno = DF_REF_REGNO (def);
+	  if (!(DF_REF_FLAGS (def) & (DF_REF_PARTIAL | DF_REF_CONDITIONAL)))
+	    bitmap_clear_range (cpy, 
+				DF_DEFS_BEGIN (dregno), 
+				DF_DEFS_COUNT (dregno));
+	  bitmap_set_bit (cpy, DF_REF_ID (def));
+	}
+    }
+  
+  /* Process the regular instructions next.  */
+  FOR_BB_INSNS (bb, insn)
+    {
+      df_ref *def_rec;
+      unsigned int uid = INSN_UID (insn);
+
+      if (!INSN_P (insn))
+	continue;
+
+      /* Now scan the uses and link them up with the defs that remain
+	 in the cpy vector.  */
+      
+      df_chain_create_bb_process_use (cpy, DF_INSN_UID_USES (uid), 0);
+
+      if (df->changeable_flags & DF_EQ_NOTES)
+	df_chain_create_bb_process_use (cpy, DF_INSN_UID_EQ_USES (uid), 0);
+
+
+      /* Since we are going forwards, process the defs second.  This
+         pass only changes the bits in cpy.  */
+      for (def_rec = DF_INSN_UID_DEFS (uid); *def_rec; def_rec++)
+	{
+	  df_ref def = *def_rec;
+	  unsigned int dregno = DF_REF_REGNO (def);
+	  if ((!(df->changeable_flags & DF_NO_HARD_REGS))
+	      || (dregno >= FIRST_PSEUDO_REGISTER))
+	    {
+	      if (!(DF_REF_FLAGS (def) & (DF_REF_PARTIAL | DF_REF_CONDITIONAL)))
+		bitmap_clear_range (cpy, 
+				    DF_DEFS_BEGIN (dregno), 
+				    DF_DEFS_COUNT (dregno));
+	      if (!(DF_REF_FLAGS (def) 
+		    & (DF_REF_MUST_CLOBBER | DF_REF_MAY_CLOBBER)))
+		bitmap_set_bit (cpy, DF_REF_ID (def));
+	    }
+	}
+    }
+
+  /* Create the chains for the artificial uses of the hard registers
+     at the end of the block.  */
+  if (!(df->changeable_flags & DF_NO_HARD_REGS))
+    df_chain_create_bb_process_use (cpy,
+				    df_get_artificial_uses (bb->index), 
+				    0);
+
+  BITMAP_FREE (cpy);
+}
+
+/* Create def-use chains from reaching use bitmaps for basic blocks
+   in BLOCKS.  */
+
+static void
+df_chain_finalize (bitmap all_blocks)
+{
+  unsigned int bb_index;
+  bitmap_iterator bi;
+  
+  EXECUTE_IF_SET_IN_BITMAP (all_blocks, 0, bb_index, bi)
+    {
+      df_chain_create_bb (bb_index);
+    }
+}
+
+
+/* Free all storage associated with the problem.  */
+
+static void
+df_chain_free (void)
+{
+  free_alloc_pool (df_chain->block_pool);
+  BITMAP_FREE (df_chain->out_of_date_transfer_functions);
+  free (df_chain);
+}
+
+
+/* Debugging info.  */
+
+static void
+df_chain_top_dump (basic_block bb, FILE *file)
+{
+  if (df_chain_problem_p (DF_DU_CHAIN))
+    {
+      rtx insn;
+      df_ref *def_rec = df_get_artificial_defs (bb->index);
+      if (*def_rec)
+	{
+	  
+	  fprintf (file, ";;  DU chains for artificial defs\n");
+	  while (*def_rec)
+	    {
+	      df_ref def = *def_rec;
+	      fprintf (file, ";;   reg %d ", DF_REF_REGNO (def));
+	      df_chain_dump (DF_REF_CHAIN (def), file);
+	      fprintf (file, "\n");
+	      def_rec++;
+	    }
+	}      
+
+      FOR_BB_INSNS (bb, insn)
+	{
+	  if (INSN_P (insn))
+	    {
+	      struct df_insn_info *insn_info = DF_INSN_INFO_GET (insn);
+	      def_rec = DF_INSN_INFO_DEFS (insn_info);
+	      if (*def_rec)
+		{
+		  fprintf (file, ";;   DU chains for insn luid %d uid %d\n", 
+			   DF_INSN_INFO_LUID (insn_info), INSN_UID (insn));
+		  
+		  while (*def_rec)
+		    {
+		      df_ref def = *def_rec;
+		      fprintf (file, ";;      reg %d ", DF_REF_REGNO (def));
+		      if (DF_REF_FLAGS (def) & DF_REF_READ_WRITE)
+			fprintf (file, "read/write ");
+		      df_chain_dump (DF_REF_CHAIN (def), file);
+		      fprintf (file, "\n");
+		      def_rec++;
+		    }
+		}
+	    }
+	}
+    }
+}
+
+
+static void
+df_chain_bottom_dump (basic_block bb, FILE *file)
+{
+  if (df_chain_problem_p (DF_UD_CHAIN))
+    {
+      rtx insn;
+      df_ref *use_rec = df_get_artificial_uses (bb->index);
+
+      if (*use_rec)
+	{
+	  fprintf (file, ";;  UD chains for artificial uses\n");
+	  while (*use_rec)
+	    {
+	      df_ref use = *use_rec;
+	      fprintf (file, ";;   reg %d ", DF_REF_REGNO (use));
+	      df_chain_dump (DF_REF_CHAIN (use), file);
+	      fprintf (file, "\n");
+	      use_rec++;
+	    }
+	}      
+
+      FOR_BB_INSNS (bb, insn)
+	{
+	  if (INSN_P (insn))
+	    {
+	      struct df_insn_info *insn_info = DF_INSN_INFO_GET (insn);
+	      df_ref *eq_use_rec = DF_INSN_INFO_EQ_USES (insn_info);
+	      use_rec = DF_INSN_INFO_USES (insn_info);
+	      if (*use_rec || *eq_use_rec)
+		{
+		  fprintf (file, ";;   UD chains for insn luid %d uid %d\n", 
+			   DF_INSN_INFO_LUID (insn_info), INSN_UID (insn));
+		  
+		  while (*use_rec)
+		    {
+		      df_ref use = *use_rec;
+		      fprintf (file, ";;      reg %d ", DF_REF_REGNO (use));
+		      if (DF_REF_FLAGS (use) & DF_REF_READ_WRITE)
+			fprintf (file, "read/write ");
+		      df_chain_dump (DF_REF_CHAIN (use), file);
+		      fprintf (file, "\n");
+		      use_rec++;
+		    }
+		  while (*eq_use_rec)
+		    {
+		      df_ref use = *eq_use_rec;
+		      fprintf (file, ";;   eq_note reg %d ", DF_REF_REGNO (use));
+		      df_chain_dump (DF_REF_CHAIN (use), file);
+		      fprintf (file, "\n");
+		      eq_use_rec++;
+		    }
+		}
+	    }
+	}
+    }
+}
+
+
+static struct df_problem problem_CHAIN =
+{
+  DF_CHAIN,                   /* Problem id.  */
+  DF_NONE,                    /* Direction.  */
+  df_chain_alloc,             /* Allocate the problem specific data.  */
+  df_chain_reset,             /* Reset global information.  */
+  NULL,                       /* 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.  */
+  df_chain_finalize,          /* Finalize function.  */
+  df_chain_free,              /* Free all of the problem information.  */
+  df_chain_fully_remove_problem,/* Remove this problem from the stack of dataflow problems.  */
+  NULL,                       /* Debugging.  */
+  df_chain_top_dump,          /* Debugging start block.  */
+  df_chain_bottom_dump,       /* Debugging end block.  */
+  NULL,                       /* Incremental solution verify start.  */
+  NULL,                       /* Incremental solution verify end.  */
+  &problem_RD,                /* Dependent problem.  */
+  TV_DF_CHAIN,                /* 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_chain_add_problem (enum df_chain_flags chain_flags)
+{
+  df_add_problem (&problem_CHAIN);
+  df_chain->local_flags = (unsigned int)chain_flags;
+  df_chain->out_of_date_transfer_functions = BITMAP_ALLOC (NULL);
+}
+
+#undef df_chain_problem_p
+
+
+/*----------------------------------------------------------------------------
+   BYTE LEVEL LIVE REGISTERS
+
+   Find the locations in the function where any use of a pseudo can
+   reach in the backwards direction.  In and out bitvectors are built
+   for each basic block.  There are two mapping functions,
+   df_byte_lr_get_regno_start and df_byte_lr_get_regno_len that are
+   used to map regnos into bit vector positions.
+
+   This problem differs from the regular df_lr function in the way
+   that subregs, *_extracts and strict_low_parts are handled. In lr
+   these are consider partial kills, here, the exact set of bytes is
+   modeled.  Note that any reg that has none of these operations is
+   only modeled with a single bit since all operations access the
+   entire register.
+
+   This problem is more brittle that the regular lr.  It currently can
+   be used in dce incrementally, but cannot be used in an environment
+   where insns are created or modified.  The problem is that the
+   mapping of regnos to bitmap positions is relatively compact, in
+   that if a pseudo does not do any of the byte wise operations, only
+   one slot is allocated, rather than a slot for each byte.  If insn
+   are created, where a subreg is used for a reg that had no subregs,
+   the mapping would be wrong.  Likewise, there are no checks to see
+   that new pseudos have been added.  These issues could be addressed
+   by adding a problem specific flag to not use the compact mapping,
+   if there was a need to do so.
+
+   ----------------------------------------------------------------------------*/
+
+/* Private data used to verify the solution for this problem.  */
+struct df_byte_lr_problem_data
+{
+  /* Expanded versions of bitvectors used in lr.  */
+  bitmap invalidated_by_call;
+  bitmap hardware_regs_used;
+
+  /* Indexed by regno, this is true if there are subregs, extracts or
+     strict_low_parts for this regno.  */
+  bitmap needs_expansion;
+
+  /* The start position and len for each regno in the various bit
+     vectors.  */ 
+  unsigned int* regno_start;  
+  unsigned int* regno_len;
+  /* An obstack for the bitmaps we need for this problem.  */
+  bitmap_obstack byte_lr_bitmaps;
+};
+
+
+/* Get the starting location for REGNO in the df_byte_lr bitmaps.  */
+
+int 
+df_byte_lr_get_regno_start (unsigned int regno)
+{
+  struct df_byte_lr_problem_data *problem_data 
+    = (struct df_byte_lr_problem_data *)df_byte_lr->problem_data;;
+  return problem_data->regno_start[regno];
+}
+
+
+/* Get the len for REGNO in the df_byte_lr bitmaps.  */
+
+int 
+df_byte_lr_get_regno_len (unsigned int regno)
+{  
+  struct df_byte_lr_problem_data *problem_data 
+    = (struct df_byte_lr_problem_data *)df_byte_lr->problem_data;;
+  return problem_data->regno_len[regno];
+}
+
+
+/* Set basic block info.  */
+
+static void
+df_byte_lr_set_bb_info (unsigned int index, 
+			struct df_byte_lr_bb_info *bb_info)
+{
+  gcc_assert (df_byte_lr);
+  gcc_assert (index < df_byte_lr->block_info_size);
+  df_byte_lr->block_info[index] = bb_info;
+}
+
+ 
+/* Free basic block info.  */
+
+static void
+df_byte_lr_free_bb_info (basic_block bb ATTRIBUTE_UNUSED, 
+			 void *vbb_info)
+{
+  struct df_byte_lr_bb_info *bb_info = (struct df_byte_lr_bb_info *) vbb_info;
+  if (bb_info)
+    {
+      BITMAP_FREE (bb_info->use);
+      BITMAP_FREE (bb_info->def);
+      BITMAP_FREE (bb_info->in);
+      BITMAP_FREE (bb_info->out);
+      pool_free (df_byte_lr->block_pool, bb_info);
+    }
+}
+
+
+/* Check all of the refs in REF_REC to see if any of them are
+   extracts, subregs or strict_low_parts.  */
+
+static void
+df_byte_lr_check_regs (df_ref *ref_rec)
+{
+  struct df_byte_lr_problem_data *problem_data 
+    = (struct df_byte_lr_problem_data *)df_byte_lr->problem_data;
+
+  for (; *ref_rec; ref_rec++)
+    {
+      df_ref ref = *ref_rec;
+      if (DF_REF_FLAGS_IS_SET (ref, DF_REF_SIGN_EXTRACT 
+			       | DF_REF_ZERO_EXTRACT 
+			       | DF_REF_STRICT_LOW_PART)
+	  || GET_CODE (DF_REF_REG (ref)) == SUBREG)
+	bitmap_set_bit (problem_data->needs_expansion, DF_REF_REGNO (ref));
+    }
+}
+
+
+/* Expand bitmap SRC which is indexed by regno to DEST which is indexed by 
+   regno_start and regno_len.  */
+
+static void
+df_byte_lr_expand_bitmap (bitmap dest, bitmap src)
+{
+  struct df_byte_lr_problem_data *problem_data 
+    = (struct df_byte_lr_problem_data *)df_byte_lr->problem_data;
+  bitmap_iterator bi;
+  unsigned int i;
+
+  bitmap_clear (dest);
+  EXECUTE_IF_SET_IN_BITMAP (src, 0, i, bi)
+    {
+      bitmap_set_range (dest, problem_data->regno_start[i], 
+			problem_data->regno_len[i]);
+    }
+}
+
+
+/* Allocate or reset bitmaps for DF_BYTE_LR blocks. The solution bits are
+   not touched unless the block is new.  */
+
+static void 
+df_byte_lr_alloc (bitmap all_blocks ATTRIBUTE_UNUSED)
+{
+  unsigned int bb_index;
+  bitmap_iterator bi;
+  basic_block bb;
+  unsigned int regno;
+  unsigned int index = 0;
+  unsigned int max_reg = max_reg_num();
+  struct df_byte_lr_problem_data *problem_data 
+    = problem_data = XNEW (struct df_byte_lr_problem_data);
+
+  df_byte_lr->problem_data = problem_data;
+
+  if (!df_byte_lr->block_pool)
+    df_byte_lr->block_pool = create_alloc_pool ("df_byte_lr_block pool", 
+					   sizeof (struct df_byte_lr_bb_info), 50);
+
+  df_grow_bb_info (df_byte_lr);
+
+  /* Create the mapping from regnos to slots. This does not change
+     unless the problem is destroyed and recreated.  In particular, if
+     we end up deleting the only insn that used a subreg, we do not
+     want to redo the mapping because this would invalidate everything
+     else.  */
+
+  bitmap_obstack_initialize (&problem_data->byte_lr_bitmaps);
+  problem_data->regno_start = XNEWVEC (unsigned int, max_reg);
+  problem_data->regno_len = XNEWVEC (unsigned int, max_reg);
+  problem_data->hardware_regs_used = BITMAP_ALLOC (&problem_data->byte_lr_bitmaps);
+  problem_data->invalidated_by_call = BITMAP_ALLOC (&problem_data->byte_lr_bitmaps);
+  problem_data->needs_expansion = BITMAP_ALLOC (&problem_data->byte_lr_bitmaps);
+  
+  /* Discover which regno's use subregs, extracts or
+     strict_low_parts.  */
+  FOR_EACH_BB (bb)
+    {
+      rtx insn;
+      FOR_BB_INSNS (bb, insn)
+	{
+	  if (INSN_P (insn))
+	    {
+	      struct df_insn_info *insn_info = DF_INSN_INFO_GET (insn);
+	      df_byte_lr_check_regs (DF_INSN_INFO_DEFS (insn_info));
+	      df_byte_lr_check_regs (DF_INSN_INFO_USES (insn_info));
+	    }
+	}
+      bitmap_set_bit (df_byte_lr->out_of_date_transfer_functions, bb->index);
+    }
+
+  bitmap_set_bit (df_byte_lr->out_of_date_transfer_functions, ENTRY_BLOCK);
+  bitmap_set_bit (df_byte_lr->out_of_date_transfer_functions, EXIT_BLOCK);
+  
+  /* Allocate the slots for each regno.  */
+  for (regno = 0; regno < max_reg; regno++)
+    {
+      int len;
+      problem_data->regno_start[regno] = index;
+      if (bitmap_bit_p (problem_data->needs_expansion, regno))
+	len = GET_MODE_SIZE (GET_MODE (regno_reg_rtx[regno]));
+      else 
+	len = 1;
+      
+      problem_data->regno_len[regno] = len;
+      index += len;
+    }
+
+  df_byte_lr_expand_bitmap (problem_data->hardware_regs_used, 
+			    df->hardware_regs_used);
+  df_byte_lr_expand_bitmap (problem_data->invalidated_by_call, 
+			    regs_invalidated_by_call_regset);
+
+  EXECUTE_IF_SET_IN_BITMAP (df_byte_lr->out_of_date_transfer_functions, 0, bb_index, bi)
+    {
+      struct df_byte_lr_bb_info *bb_info = df_byte_lr_get_bb_info (bb_index);
+      if (bb_info)
+	{ 
+	  bitmap_clear (bb_info->def);
+	  bitmap_clear (bb_info->use);
+	}
+      else
+	{ 
+	  bb_info = (struct df_byte_lr_bb_info *) pool_alloc (df_byte_lr->block_pool);
+	  df_byte_lr_set_bb_info (bb_index, bb_info);
+	  bb_info->use = BITMAP_ALLOC (&problem_data->byte_lr_bitmaps);
+	  bb_info->def = BITMAP_ALLOC (&problem_data->byte_lr_bitmaps);
+	  bb_info->in = BITMAP_ALLOC (&problem_data->byte_lr_bitmaps);
+	  bb_info->out = BITMAP_ALLOC (&problem_data->byte_lr_bitmaps);
+	}
+    }
+  
+  df_byte_lr->optional_p = true;
+}
+
+
+/* Reset the global solution for recalculation.  */
+
+static void 
+df_byte_lr_reset (bitmap all_blocks)
+{
+  unsigned int bb_index;
+  bitmap_iterator bi;
+
+  EXECUTE_IF_SET_IN_BITMAP (all_blocks, 0, bb_index, bi)
+    {
+      struct df_byte_lr_bb_info *bb_info = df_byte_lr_get_bb_info (bb_index);
+      gcc_assert (bb_info);
+      bitmap_clear (bb_info->in);
+      bitmap_clear (bb_info->out);
+    }
+}
+
+
+/* Compute local live register info for basic block BB.  */
+
+static void
+df_byte_lr_bb_local_compute (unsigned int bb_index)
+{
+  struct df_byte_lr_problem_data *problem_data 
+    = (struct df_byte_lr_problem_data *)df_byte_lr->problem_data;
+  basic_block bb = BASIC_BLOCK (bb_index);
+  struct df_byte_lr_bb_info *bb_info = df_byte_lr_get_bb_info (bb_index);
+  rtx insn;
+  df_ref *def_rec;
+  df_ref *use_rec;
+
+  /* Process the registers set in an exception handler.  */
+  for (def_rec = df_get_artificial_defs (bb_index); *def_rec; def_rec++)
+    {
+      df_ref def = *def_rec;
+      if ((DF_REF_FLAGS (def) & DF_REF_AT_TOP) == 0)
+	{
+	  unsigned int dregno = DF_REF_REGNO (def);
+	  unsigned int start = problem_data->regno_start[dregno];
+	  unsigned int len = problem_data->regno_len[dregno];
+	  bitmap_set_range (bb_info->def, start, len);
+	  bitmap_clear_range (bb_info->use, start, len);
+	}
+    }
+
+  /* Process the hardware registers that are always live.  */
+  for (use_rec = df_get_artificial_uses (bb_index); *use_rec; use_rec++)
+    {
+      df_ref use = *use_rec;
+      /* Add use to set of uses in this BB.  */
+      if ((DF_REF_FLAGS (use) & DF_REF_AT_TOP) == 0)
+	{
+	  unsigned int uregno = DF_REF_REGNO (use);
+	  unsigned int start = problem_data->regno_start[uregno];
+	  unsigned int len = problem_data->regno_len[uregno];
+	  bitmap_set_range (bb_info->use, start, len);
+	}
+    }
+
+  FOR_BB_INSNS_REVERSE (bb, insn)
+    {
+      unsigned int uid = INSN_UID (insn);
+
+      if (!INSN_P (insn))
+	continue;	
+
+      for (def_rec = DF_INSN_UID_DEFS (uid); *def_rec; def_rec++)
+	{
+	  df_ref def = *def_rec;
+	  /* If the def is to only part of the reg, it does
+	     not kill the other defs that reach here.  */
+	  if (!(DF_REF_FLAGS (def) & (DF_REF_CONDITIONAL)))
+	    {
+	      unsigned int dregno = DF_REF_REGNO (def);
+	      unsigned int start = problem_data->regno_start[dregno];
+	      unsigned int len = problem_data->regno_len[dregno];
+	      unsigned int sb;
+	      unsigned int lb;
+	      if (!df_compute_accessed_bytes (def, DF_MM_MUST, &sb, &lb))
+		{
+		  start += sb;
+		  len = lb - sb;
+		}
+	      if (len)
+		{
+		  bitmap_set_range (bb_info->def, start, len);
+		  bitmap_clear_range (bb_info->use, start, len);
+		}
+	    }
+	}
+
+      for (use_rec = DF_INSN_UID_USES (uid); *use_rec; use_rec++)
+	{
+	  df_ref use = *use_rec;
+	  unsigned int uregno = DF_REF_REGNO (use);
+	  unsigned int start = problem_data->regno_start[uregno];
+	  unsigned int len = problem_data->regno_len[uregno];
+	  unsigned int sb;
+	  unsigned int lb;
+	  if (!df_compute_accessed_bytes (use, DF_MM_MAY, &sb, &lb))
+	    {
+	      start += sb;
+	      len = lb - sb;
+	    }
+	  /* Add use to set of uses in this BB.  */
+	  if (len)
+	    bitmap_set_range (bb_info->use, start, len);
+	}
+    }
+
+  /* Process the registers set in an exception handler or the hard
+     frame pointer if this block is the target of a non local
+     goto.  */
+  for (def_rec = df_get_artificial_defs (bb_index); *def_rec; def_rec++)
+    {
+      df_ref def = *def_rec;
+      if (DF_REF_FLAGS (def) & DF_REF_AT_TOP)
+	{
+	  unsigned int dregno = DF_REF_REGNO (def);
+	  unsigned int start = problem_data->regno_start[dregno];
+	  unsigned int len = problem_data->regno_len[dregno];
+	  bitmap_set_range (bb_info->def, start, len);
+	  bitmap_clear_range (bb_info->use, start, len);
+	}
+    }
+  
+#ifdef EH_USES
+  /* Process the uses that are live into an exception handler.  */
+  for (use_rec = df_get_artificial_uses (bb_index); *use_rec; use_rec++)
+    {
+      df_ref use = *use_rec;
+      /* Add use to set of uses in this BB.  */
+      if (DF_REF_FLAGS (use) & DF_REF_AT_TOP)
+	{
+	  unsigned int uregno = DF_REF_REGNO (use);
+	  unsigned int start = problem_data->regno_start[uregno];
+	  unsigned int len = problem_data->regno_len[uregno];
+	  bitmap_set_range (bb_info->use, start, len);
+	}
+    }
+#endif
+}
+
+
+/* Compute local live register info for each basic block within BLOCKS.  */
+
+static void
+df_byte_lr_local_compute (bitmap all_blocks ATTRIBUTE_UNUSED)
+{
+  unsigned int bb_index;
+  bitmap_iterator bi;
+
+  EXECUTE_IF_SET_IN_BITMAP (df_byte_lr->out_of_date_transfer_functions, 0, bb_index, bi)
+    {
+      if (bb_index == EXIT_BLOCK)
+	{
+	  /* The exit block is special for this problem and its bits are
+	     computed from thin air.  */
+	  struct df_byte_lr_bb_info *bb_info = df_byte_lr_get_bb_info (EXIT_BLOCK);
+	  df_byte_lr_expand_bitmap (bb_info->use, df->exit_block_uses);
+	}
+      else
+	df_byte_lr_bb_local_compute (bb_index);
+    }
+
+  bitmap_clear (df_byte_lr->out_of_date_transfer_functions);
+}
+
+
+/* Initialize the solution vectors.  */
+
+static void 
+df_byte_lr_init (bitmap all_blocks)
+{
+  unsigned int bb_index;
+  bitmap_iterator bi;
+
+  EXECUTE_IF_SET_IN_BITMAP (all_blocks, 0, bb_index, bi)
+    {
+      struct df_byte_lr_bb_info *bb_info = df_byte_lr_get_bb_info (bb_index);
+      bitmap_copy (bb_info->in, bb_info->use);
+      bitmap_clear (bb_info->out);
+    }
+}
+
+
+/* Confluence function that processes infinite loops.  This might be a
+   noreturn function that throws.  And even if it isn't, getting the
+   unwind info right helps debugging.  */
+static void
+df_byte_lr_confluence_0 (basic_block bb)
+{
+  struct df_byte_lr_problem_data *problem_data 
+    = (struct df_byte_lr_problem_data *)df_byte_lr->problem_data;
+  bitmap op1 = df_byte_lr_get_bb_info (bb->index)->out;
+  if (bb != EXIT_BLOCK_PTR)
+    bitmap_copy (op1, problem_data->hardware_regs_used);
+} 
+
+
+/* Confluence function that ignores fake edges.  */
+
+static void
+df_byte_lr_confluence_n (edge e)
+{
+  struct df_byte_lr_problem_data *problem_data 
+    = (struct df_byte_lr_problem_data *)df_byte_lr->problem_data;
+  bitmap op1 = df_byte_lr_get_bb_info (e->src->index)->out;
+  bitmap op2 = df_byte_lr_get_bb_info (e->dest->index)->in;
+ 
+  /* Call-clobbered registers die across exception and call edges.  */
+  /* ??? Abnormal call edges ignored for the moment, as this gets
+     confused by sibling call edges, which crashes reg-stack.  */
+  if (e->flags & EDGE_EH)
+    bitmap_ior_and_compl_into (op1, op2, problem_data->invalidated_by_call);
+  else
+    bitmap_ior_into (op1, op2);
+
+  bitmap_ior_into (op1, problem_data->hardware_regs_used);
+} 
+
+
+/* Transfer function.  */
+
+static bool
+df_byte_lr_transfer_function (int bb_index)
+{
+  struct df_byte_lr_bb_info *bb_info = df_byte_lr_get_bb_info (bb_index);
+  bitmap in = bb_info->in;
+  bitmap out = bb_info->out;
+  bitmap use = bb_info->use;
+  bitmap def = bb_info->def;
+
+  return bitmap_ior_and_compl (in, use, out, def);
+}
+
+
+/* Free all storage associated with the problem.  */
+
+static void
+df_byte_lr_free (void)
+{
+  struct df_byte_lr_problem_data *problem_data
+    = (struct df_byte_lr_problem_data *)df_byte_lr->problem_data;
+
+
+  if (df_byte_lr->block_info)
+    {
+      free_alloc_pool (df_byte_lr->block_pool);
+      df_byte_lr->block_info_size = 0;
+      free (df_byte_lr->block_info);
+    }
+
+  BITMAP_FREE (df_byte_lr->out_of_date_transfer_functions);
+  bitmap_obstack_release (&problem_data->byte_lr_bitmaps);
+  free (problem_data->regno_start);
+  free (problem_data->regno_len);
+  free (problem_data);
+  free (df_byte_lr);
+}
+
+
+/* Debugging info at top of bb.  */
+
+static void
+df_byte_lr_top_dump (basic_block bb, FILE *file)
+{
+  struct df_byte_lr_bb_info *bb_info = df_byte_lr_get_bb_info (bb->index);
+  if (!bb_info || !bb_info->in)
+    return;
+      
+  fprintf (file, ";; blr  in  \t");
+  df_print_byte_regset (file, bb_info->in);
+  fprintf (file, ";; blr  use \t");
+  df_print_byte_regset (file, bb_info->use);
+  fprintf (file, ";; blr  def \t");
+  df_print_byte_regset (file, bb_info->def);
+}  
+
+
+/* Debugging info at bottom of bb.  */
+
+static void
+df_byte_lr_bottom_dump (basic_block bb, FILE *file)
+{
+  struct df_byte_lr_bb_info *bb_info = df_byte_lr_get_bb_info (bb->index);
+  if (!bb_info || !bb_info->out)
+    return;
+  
+  fprintf (file, ";; blr  out \t");
+  df_print_byte_regset (file, bb_info->out);
+}  
+
+
+/* All of the information associated with every instance of the problem.  */
+
+static struct df_problem problem_BYTE_LR =
+{
+  DF_BYTE_LR,                      /* Problem id.  */
+  DF_BACKWARD,                     /* Direction.  */
+  df_byte_lr_alloc,                /* Allocate the problem specific data.  */
+  df_byte_lr_reset,                /* Reset global information.  */
+  df_byte_lr_free_bb_info,         /* Free basic block info.  */
+  df_byte_lr_local_compute,        /* Local compute function.  */
+  df_byte_lr_init,                 /* Init the solution specific data.  */
+  df_worklist_dataflow,            /* Worklist solver.  */
+  df_byte_lr_confluence_0,         /* Confluence operator 0.  */ 
+  df_byte_lr_confluence_n,         /* Confluence operator n.  */ 
+  df_byte_lr_transfer_function,    /* Transfer function.  */
+  NULL,                            /* Finalize function.  */
+  df_byte_lr_free,                 /* Free all of the problem information.  */
+  df_byte_lr_free,                 /* Remove this problem from the stack of dataflow problems.  */
+  NULL,                            /* Debugging.  */
+  df_byte_lr_top_dump,             /* Debugging start block.  */
+  df_byte_lr_bottom_dump,          /* Debugging end block.  */
+  NULL,                            /* Incremental solution verify start.  */
+  NULL,                            /* Incremental solution verify end.  */
+  NULL,                            /* Dependent problem.  */
+  TV_DF_BYTE_LR,                   /* 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_byte_lr_add_problem (void)
+{
+  df_add_problem (&problem_BYTE_LR);
+  /* These will be initialized when df_scan_blocks processes each
+     block.  */
+  df_byte_lr->out_of_date_transfer_functions = BITMAP_ALLOC (NULL);
+}
+
+
+/* Simulate the effects of the defs of INSN on LIVE.  */
+
+void
+df_byte_lr_simulate_defs (rtx insn, bitmap live)
+{
+  struct df_byte_lr_problem_data *problem_data 
+    = (struct df_byte_lr_problem_data *)df_byte_lr->problem_data;
+  df_ref *def_rec;
+  unsigned int uid = INSN_UID (insn);
+
+  for (def_rec = DF_INSN_UID_DEFS (uid); *def_rec; def_rec++)
+    {
+      df_ref def = *def_rec;
+
+      /* If the def is to only part of the reg, it does
+	 not kill the other defs that reach here.  */
+      if (!(DF_REF_FLAGS (def) & DF_REF_CONDITIONAL))
+	{
+	  unsigned int dregno = DF_REF_REGNO (def);
+	  unsigned int start = problem_data->regno_start[dregno];
+	  unsigned int len = problem_data->regno_len[dregno];
+	  unsigned int sb;
+	  unsigned int lb;
+	  if (!df_compute_accessed_bytes (def, DF_MM_MUST, &sb, &lb))
+	    {
+	      start += sb;
+	      len = lb - sb;
+	    }
+
+	  if (len)
+	    bitmap_clear_range (live, start, len);
+	}
+    }
+}  
+
+
+/* Simulate the effects of the uses of INSN on LIVE.  */
+
+void 
+df_byte_lr_simulate_uses (rtx insn, bitmap live)
+{
+  struct df_byte_lr_problem_data *problem_data 
+    = (struct df_byte_lr_problem_data *)df_byte_lr->problem_data;
+  df_ref *use_rec;
+  unsigned int uid = INSN_UID (insn);
+
+  for (use_rec = DF_INSN_UID_USES (uid); *use_rec; use_rec++)
+    {
+      df_ref use = *use_rec;
+      unsigned int uregno = DF_REF_REGNO (use);
+      unsigned int start = problem_data->regno_start[uregno];
+      unsigned int len = problem_data->regno_len[uregno];
+      unsigned int sb;
+      unsigned int lb;
+      
+      if (!df_compute_accessed_bytes (use, DF_MM_MAY, &sb, &lb))
+	{
+	  start += sb;
+	  len = lb - sb;
+	}
+      
+      /* Add use to set of uses in this BB.  */
+      if (len)
+	bitmap_set_range (live, start, len);
+    }
+}
+
+
+/* Apply the artificial uses and defs at the top of BB in a forwards
+   direction.  */
+
+void 
+df_byte_lr_simulate_artificial_refs_at_top (basic_block bb, bitmap live)
+{
+  struct df_byte_lr_problem_data *problem_data 
+    = (struct df_byte_lr_problem_data *)df_byte_lr->problem_data;
+  df_ref *def_rec;
+#ifdef EH_USES
+  df_ref *use_rec;
+#endif
+  int bb_index = bb->index;
+  
+#ifdef EH_USES
+  for (use_rec = df_get_artificial_uses (bb_index); *use_rec; use_rec++)
+    {
+      df_ref use = *use_rec;
+      if (DF_REF_FLAGS (use) & DF_REF_AT_TOP)
+	{
+	  unsigned int uregno = DF_REF_REGNO (use);
+	  unsigned int start = problem_data->regno_start[uregno];
+	  unsigned int len = problem_data->regno_len[uregno];
+	  bitmap_set_range (live, start, len);
+	}
+    }
+#endif
+
+  for (def_rec = df_get_artificial_defs (bb_index); *def_rec; def_rec++)
+    {
+      df_ref def = *def_rec;
+      if (DF_REF_FLAGS (def) & DF_REF_AT_TOP)
+	{      
+	  unsigned int dregno = DF_REF_REGNO (def);
+	  unsigned int start = problem_data->regno_start[dregno];
+	  unsigned int len = problem_data->regno_len[dregno];
+	  bitmap_clear_range (live, start, len);
+	}
+    }
+}
+
+
+/* Apply the artificial uses and defs at the end of BB in a backwards
+   direction.  */
+
+void 
+df_byte_lr_simulate_artificial_refs_at_end (basic_block bb, bitmap live)
+{
+  struct df_byte_lr_problem_data *problem_data 
+    = (struct df_byte_lr_problem_data *)df_byte_lr->problem_data;
+  df_ref *def_rec;
+  df_ref *use_rec;
+  int bb_index = bb->index;
+  
+  for (def_rec = df_get_artificial_defs (bb_index); *def_rec; def_rec++)
+    {
+      df_ref def = *def_rec;
+      if ((DF_REF_FLAGS (def) & DF_REF_AT_TOP) == 0)
+	{
+	  unsigned int dregno = DF_REF_REGNO (def);
+	  unsigned int start = problem_data->regno_start[dregno];
+	  unsigned int len = problem_data->regno_len[dregno];
+	  bitmap_clear_range (live, start, len);
+	}
+    }
+
+  for (use_rec = df_get_artificial_uses (bb_index); *use_rec; use_rec++)
+    {
+      df_ref use = *use_rec;
+      if ((DF_REF_FLAGS (use) & DF_REF_AT_TOP) == 0)
+	{
+	  unsigned int uregno = DF_REF_REGNO (use);
+	  unsigned int start = problem_data->regno_start[uregno];
+	  unsigned int len = problem_data->regno_len[uregno];
+	  bitmap_set_range (live, start, len);
+	}
+    }
+}
+
+
+
+/*----------------------------------------------------------------------------
+   This problem computes REG_DEAD and REG_UNUSED notes.
+   ----------------------------------------------------------------------------*/
+
+static void 
+df_note_alloc (bitmap all_blocks ATTRIBUTE_UNUSED)
+{
+  df_note->optional_p = true;
+}
+
+#ifdef REG_DEAD_DEBUGGING
+static void 
+df_print_note (const char *prefix, rtx insn, rtx note)
+{
+  if (dump_file)
+    {
+      fprintf (dump_file, "%s %d ", prefix, INSN_UID (insn));
+      print_rtl (dump_file, note);
+      fprintf (dump_file, "\n");
+    }
+}
+#endif
+
+
+/* After reg-stack, the x86 floating point stack regs are difficult to
+   analyze because of all of the pushes, pops and rotations.  Thus, we
+   just leave the notes alone. */
+
+#ifdef STACK_REGS
+static inline bool 
+df_ignore_stack_reg (int regno)
+{
+  return regstack_completed
+    && IN_RANGE (regno, FIRST_STACK_REG, LAST_STACK_REG);
+}
+#else
+static inline bool 
+df_ignore_stack_reg (int regno ATTRIBUTE_UNUSED)
+{
+  return false;
+}
+#endif
+
+
+/* Remove all of the REG_DEAD or REG_UNUSED notes from INSN and add
+   them to OLD_DEAD_NOTES and OLD_UNUSED_NOTES.  */
+
+static void
+df_kill_notes (rtx insn, rtx *old_dead_notes, rtx *old_unused_notes)
+{
+  rtx *pprev = &REG_NOTES (insn);
+  rtx link = *pprev;
+  rtx dead = NULL;
+  rtx unused = NULL;
+
+  while (link)
+    {
+      switch (REG_NOTE_KIND (link))
+	{
+	case REG_DEAD:
+	  /* After reg-stack, we need to ignore any unused notes 
+	     for the stack registers.  */
+	  if (df_ignore_stack_reg (REGNO (XEXP (link, 0))))
+	    {
+	      pprev = &XEXP (link, 1);
+	      link = *pprev;
+	    }
+	  else
+	    {
+	      rtx next = XEXP (link, 1);
+#ifdef REG_DEAD_DEBUGGING
+	      df_print_note ("deleting: ", insn, link);
+#endif
+	      XEXP (link, 1) = dead;
+	      dead = link;
+	      *pprev = link = next;
+	    }
+	  break;
+
+	case REG_UNUSED:
+	  /* After reg-stack, we need to ignore any unused notes 
+	     for the stack registers.  */
+	  if (df_ignore_stack_reg (REGNO (XEXP (link, 0))))
+	    {
+	      pprev = &XEXP (link, 1);
+	      link = *pprev;
+	    }
+	  else
+	    {
+	      rtx next = XEXP (link, 1);
+#ifdef REG_DEAD_DEBUGGING
+	      df_print_note ("deleting: ", insn, link);
+#endif
+	      XEXP (link, 1) = unused;
+	      unused = link;
+	      *pprev = link = next;
+	    }
+	  break;
+	  
+	default:
+	  pprev = &XEXP (link, 1);
+	  link = *pprev;
+	  break;
+	}
+    }
+
+  *old_dead_notes = dead;
+  *old_unused_notes = unused;
+}
+
+
+/* Set a NOTE_TYPE note for REG in INSN.  Try to pull it from the OLD
+   list, otherwise create a new one.  */
+
+static inline rtx
+df_set_note (enum reg_note note_type, rtx insn, rtx old, rtx reg)
+{
+  rtx curr = old;
+  rtx prev = NULL;
+
+  while (curr)
+    if (XEXP (curr, 0) == reg)
+      {
+	if (prev)
+	  XEXP (prev, 1) = XEXP (curr, 1);
+	else
+	  old = XEXP (curr, 1);
+	XEXP (curr, 1) = REG_NOTES (insn);
+	REG_NOTES (insn) = curr;
+	return old;
+      }
+    else
+      {
+	prev = curr;
+	curr = XEXP (curr, 1);
+      }
+  
+  /* Did not find the note.  */
+  add_reg_note (insn, note_type, reg);
+  return old;
+}
+
+/* A subroutine of df_set_unused_notes_for_mw, with a selection of its
+   arguments.  Return true if the register value described by MWS's
+   mw_reg is known to be completely unused, and if mw_reg can therefore
+   be used in a REG_UNUSED note.  */
+
+static bool
+df_whole_mw_reg_unused_p (struct df_mw_hardreg *mws,
+			  bitmap live, bitmap artificial_uses)
+{
+  unsigned int r;
+
+  /* If MWS describes a partial reference, create REG_UNUSED notes for
+     individual hard registers.  */
+  if (mws->flags & DF_REF_PARTIAL)
+    return false;
+
+  /* Likewise if some part of the register is used.  */
+  for (r = mws->start_regno; r <= mws->end_regno; r++)
+    if (bitmap_bit_p (live, r)
+	|| bitmap_bit_p (artificial_uses, r))
+      return false;
+
+  gcc_assert (REG_P (mws->mw_reg));
+  return true;
+}
+
+/* Set the REG_UNUSED notes for the multiword hardreg defs in INSN
+   based on the bits in LIVE.  Do not generate notes for registers in
+   artificial uses.  DO_NOT_GEN is updated so that REG_DEAD notes are
+   not generated if the reg is both read and written by the
+   instruction.
+*/
+
+static rtx
+df_set_unused_notes_for_mw (rtx insn, rtx old, struct df_mw_hardreg *mws,
+			    bitmap live, bitmap do_not_gen, 
+			    bitmap artificial_uses)
+{
+  unsigned int r;
+  
+#ifdef REG_DEAD_DEBUGGING
+  if (dump_file)
+    fprintf (dump_file, "mw_set_unused looking at mws[%d..%d]\n", 
+	     mws->start_regno, mws->end_regno);
+#endif
+
+  if (df_whole_mw_reg_unused_p (mws, live, artificial_uses))
+    {
+      unsigned int regno = mws->start_regno;
+      old = df_set_note (REG_UNUSED, insn, old, mws->mw_reg);
+
+#ifdef REG_DEAD_DEBUGGING
+      df_print_note ("adding 1: ", insn, REG_NOTES (insn));
+#endif
+      bitmap_set_bit (do_not_gen, regno);
+      /* Only do this if the value is totally dead.  */
+    }
+  else
+    for (r = mws->start_regno; r <= mws->end_regno; r++)
+      {
+	if (!bitmap_bit_p (live, r)
+	    && !bitmap_bit_p (artificial_uses, r))
+	  {
+	    old = df_set_note (REG_UNUSED, insn, old, regno_reg_rtx[r]);
+#ifdef REG_DEAD_DEBUGGING
+	    df_print_note ("adding 2: ", insn, REG_NOTES (insn));
+#endif
+	  }
+	bitmap_set_bit (do_not_gen, r);
+      }
+  return old;
+}
+
+
+/* A subroutine of df_set_dead_notes_for_mw, with a selection of its
+   arguments.  Return true if the register value described by MWS's
+   mw_reg is known to be completely dead, and if mw_reg can therefore
+   be used in a REG_DEAD note.  */
+
+static bool
+df_whole_mw_reg_dead_p (struct df_mw_hardreg *mws,
+			bitmap live, bitmap artificial_uses,
+			bitmap do_not_gen)
+{
+  unsigned int r;
+
+  /* If MWS describes a partial reference, create REG_DEAD notes for
+     individual hard registers.  */
+  if (mws->flags & DF_REF_PARTIAL)
+    return false;
+
+  /* Likewise if some part of the register is not dead.  */
+  for (r = mws->start_regno; r <= mws->end_regno; r++)
+    if (bitmap_bit_p (live, r)
+	|| bitmap_bit_p (artificial_uses, r)
+	|| bitmap_bit_p (do_not_gen, r))
+      return false;
+
+  gcc_assert (REG_P (mws->mw_reg));
+  return true;
+}
+
+/* Set the REG_DEAD notes for the multiword hardreg use in INSN based
+   on the bits in LIVE.  DO_NOT_GEN is used to keep REG_DEAD notes
+   from being set if the instruction both reads and writes the
+   register.  */
+
+static rtx
+df_set_dead_notes_for_mw (rtx insn, rtx old, struct df_mw_hardreg *mws,
+			  bitmap live, bitmap do_not_gen,
+			  bitmap artificial_uses)
+{
+  unsigned int r;
+  
+#ifdef REG_DEAD_DEBUGGING
+  if (dump_file)
+    {
+      fprintf (dump_file, "mw_set_dead looking at mws[%d..%d]\n  do_not_gen =", 
+	       mws->start_regno, mws->end_regno);
+      df_print_regset (dump_file, do_not_gen);
+      fprintf (dump_file, "  live =");
+      df_print_regset (dump_file, live);
+      fprintf (dump_file, "  artificial uses =");
+      df_print_regset (dump_file, artificial_uses);
+    }
+#endif
+
+  if (df_whole_mw_reg_dead_p (mws, live, artificial_uses, do_not_gen))
+    {
+      /* Add a dead note for the entire multi word register.  */
+      old = df_set_note (REG_DEAD, insn, old, mws->mw_reg);
+#ifdef REG_DEAD_DEBUGGING
+      df_print_note ("adding 1: ", insn, REG_NOTES (insn));
+#endif
+    }
+  else
+    {
+      for (r = mws->start_regno; r <= mws->end_regno; r++)
+	if (!bitmap_bit_p (live, r)
+	    && !bitmap_bit_p (artificial_uses, r)
+	    && !bitmap_bit_p (do_not_gen, r))
+	  {
+	    old = df_set_note (REG_DEAD, insn, old, regno_reg_rtx[r]);
+#ifdef REG_DEAD_DEBUGGING
+	    df_print_note ("adding 2: ", insn, REG_NOTES (insn));
+#endif
+	  }
+    }
+  return old;
+}
+
+
+/* Create a REG_UNUSED note if necessary for DEF in INSN updating
+   LIVE.  Do not generate notes for registers in ARTIFICIAL_USES.  */
+
+static rtx
+df_create_unused_note (rtx insn, rtx old, df_ref def, 
+		       bitmap live, bitmap artificial_uses)
+{
+  unsigned int dregno = DF_REF_REGNO (def);
+  
+#ifdef REG_DEAD_DEBUGGING
+  if (dump_file)
+    {
+      fprintf (dump_file, "  regular looking at def ");
+      df_ref_debug (def, dump_file);
+    }
+#endif
+
+  if (!(bitmap_bit_p (live, dregno)
+	|| (DF_REF_FLAGS (def) & DF_REF_MW_HARDREG)
+	|| bitmap_bit_p (artificial_uses, dregno)
+	|| df_ignore_stack_reg (dregno)))
+    {
+      rtx reg = (DF_REF_LOC (def)) 
+                ? *DF_REF_REAL_LOC (def): DF_REF_REG (def);
+      old = df_set_note (REG_UNUSED, insn, old, reg);
+#ifdef REG_DEAD_DEBUGGING
+      df_print_note ("adding 3: ", insn, REG_NOTES (insn));
+#endif
+    }
+  
+  return old;
+}
+
+
+/* Recompute the REG_DEAD and REG_UNUSED notes and compute register
+   info: lifetime, bb, and number of defs and uses for basic block
+   BB.  The three bitvectors are scratch regs used here.  */
+
+static void
+df_note_bb_compute (unsigned int bb_index, 
+		    bitmap live, bitmap do_not_gen, bitmap artificial_uses)
+{
+  basic_block bb = BASIC_BLOCK (bb_index);
+  rtx insn;
+  df_ref *def_rec;
+  df_ref *use_rec;
+
+  bitmap_copy (live, df_get_live_out (bb));
+  bitmap_clear (artificial_uses);
+
+#ifdef REG_DEAD_DEBUGGING
+  if (dump_file)
+    {
+      fprintf (dump_file, "live at bottom ");
+      df_print_regset (dump_file, live);
+    }
+#endif
+
+  /* Process the artificial defs and uses at the bottom of the block
+     to begin processing.  */
+  for (def_rec = df_get_artificial_defs (bb_index); *def_rec; def_rec++)
+    {
+      df_ref def = *def_rec;
+#ifdef REG_DEAD_DEBUGGING
+      if (dump_file)
+	fprintf (dump_file, "artificial def %d\n", DF_REF_REGNO (def));
+#endif
+
+      if ((DF_REF_FLAGS (def) & DF_REF_AT_TOP) == 0)
+	bitmap_clear_bit (live, DF_REF_REGNO (def));
+    }
+
+  for (use_rec = df_get_artificial_uses (bb_index); *use_rec; use_rec++)
+    {
+      df_ref use = *use_rec;
+      if ((DF_REF_FLAGS (use) & DF_REF_AT_TOP) == 0)
+	{
+	  unsigned int regno = DF_REF_REGNO (use);
+	  bitmap_set_bit (live, regno);
+	  
+	  /* Notes are not generated for any of the artificial registers
+	     at the bottom of the block.  */
+	  bitmap_set_bit (artificial_uses, regno);
+	}
+    }
+  
+#ifdef REG_DEAD_DEBUGGING
+  if (dump_file)
+    {
+      fprintf (dump_file, "live before artificials out ");
+      df_print_regset (dump_file, live);
+    }
+#endif
+
+  FOR_BB_INSNS_REVERSE (bb, insn)
+    {
+      unsigned int uid = INSN_UID (insn);
+      struct df_mw_hardreg **mws_rec;
+      rtx old_dead_notes;
+      rtx old_unused_notes;
+ 
+      if (!INSN_P (insn))
+	continue;
+
+      bitmap_clear (do_not_gen);
+      df_kill_notes (insn, &old_dead_notes, &old_unused_notes);
+
+      /* Process the defs.  */
+      if (CALL_P (insn))
+	{
+#ifdef REG_DEAD_DEBUGGING
+	  if (dump_file)
+	    {
+	      fprintf (dump_file, "processing call %d\n  live =", INSN_UID (insn));
+	      df_print_regset (dump_file, live);
+	    }
+#endif
+	  /* We only care about real sets for calls.  Clobbers cannot
+	     be depended on to really die.  */
+	  mws_rec = DF_INSN_UID_MWS (uid);
+	  while (*mws_rec)
+	    {
+	      struct df_mw_hardreg *mws = *mws_rec; 
+	      if ((DF_MWS_REG_DEF_P (mws)) 
+		  && !df_ignore_stack_reg (mws->start_regno))
+		old_unused_notes 
+		  = df_set_unused_notes_for_mw (insn, old_unused_notes, 
+						mws, live, do_not_gen, 
+						artificial_uses);
+	      mws_rec++;
+	    }
+
+	  /* All of the defs except the return value are some sort of
+	     clobber.  This code is for the return.  */
+	  for (def_rec = DF_INSN_UID_DEFS (uid); *def_rec; def_rec++)
+	    {
+	      df_ref def = *def_rec;
+	      unsigned int dregno = DF_REF_REGNO (def);
+	      if (!DF_REF_FLAGS_IS_SET (def, DF_REF_MUST_CLOBBER | DF_REF_MAY_CLOBBER))
+		{
+		  old_unused_notes
+		    = df_create_unused_note (insn, old_unused_notes, 
+					     def, live, artificial_uses);
+		  bitmap_set_bit (do_not_gen, dregno);
+		}
+
+	      if (!DF_REF_FLAGS_IS_SET (def, DF_REF_PARTIAL | DF_REF_CONDITIONAL))
+		bitmap_clear_bit (live, dregno);
+	    }
+	}
+      else
+	{
+	  /* Regular insn.  */
+	  mws_rec = DF_INSN_UID_MWS (uid);
+	  while (*mws_rec)
+	    {
+	      struct df_mw_hardreg *mws = *mws_rec; 
+	      if (DF_MWS_REG_DEF_P (mws))
+		old_unused_notes
+		  = df_set_unused_notes_for_mw (insn, old_unused_notes, 
+						mws, live, do_not_gen, 
+						artificial_uses);
+	      mws_rec++;
+	    }
+
+	  for (def_rec = DF_INSN_UID_DEFS (uid); *def_rec; def_rec++)
+	    {
+	      df_ref def = *def_rec;
+	      unsigned int dregno = DF_REF_REGNO (def);
+	      old_unused_notes
+		= df_create_unused_note (insn, old_unused_notes, 
+					 def, live, artificial_uses);
+
+	      if (!DF_REF_FLAGS_IS_SET (def, DF_REF_MUST_CLOBBER | DF_REF_MAY_CLOBBER))
+		bitmap_set_bit (do_not_gen, dregno);
+
+	      if (!DF_REF_FLAGS_IS_SET (def, DF_REF_PARTIAL | DF_REF_CONDITIONAL))
+		bitmap_clear_bit (live, dregno);
+	    }
+	}
+      
+      /* Process the uses.  */
+      mws_rec = DF_INSN_UID_MWS (uid);
+      while (*mws_rec)
+	{
+	  struct df_mw_hardreg *mws = *mws_rec; 
+	  if ((DF_MWS_REG_DEF_P (mws))  
+	      && !df_ignore_stack_reg (mws->start_regno))
+	    old_dead_notes
+	      = df_set_dead_notes_for_mw (insn, old_dead_notes, 
+					  mws, live, do_not_gen,
+					  artificial_uses);
+	  mws_rec++;
+	}
+
+      for (use_rec = DF_INSN_UID_USES (uid); *use_rec; use_rec++)
+	{
+	  df_ref use = *use_rec;
+	  unsigned int uregno = DF_REF_REGNO (use);
+
+#ifdef REG_DEAD_DEBUGGING
+	  if (dump_file)
+	    {
+	      fprintf (dump_file, "  regular looking at use ");
+	      df_ref_debug (use, dump_file);
+	    }
+#endif
+	  if (!bitmap_bit_p (live, uregno))
+	    {
+	      if ( (!(DF_REF_FLAGS (use) & DF_REF_MW_HARDREG))
+		   && (!bitmap_bit_p (do_not_gen, uregno))
+		   && (!bitmap_bit_p (artificial_uses, uregno))
+		   && (!(DF_REF_FLAGS (use) & DF_REF_READ_WRITE))
+		   && (!df_ignore_stack_reg (uregno)))
+		{
+		  rtx reg = (DF_REF_LOC (use)) 
+                            ? *DF_REF_REAL_LOC (use) : DF_REF_REG (use);
+		  old_dead_notes = df_set_note (REG_DEAD, insn, old_dead_notes, reg);
+
+#ifdef REG_DEAD_DEBUGGING
+		  df_print_note ("adding 4: ", insn, REG_NOTES (insn));
+#endif
+		}
+	      /* This register is now live.  */
+	      bitmap_set_bit (live, uregno);
+	    }
+	}
+
+      while (old_unused_notes)
+	{
+	  rtx next = XEXP (old_unused_notes, 1);
+	  free_EXPR_LIST_node (old_unused_notes);
+	  old_unused_notes = next;
+	}
+      while (old_dead_notes)
+	{
+	  rtx next = XEXP (old_dead_notes, 1);
+	  free_EXPR_LIST_node (old_dead_notes);
+	  old_dead_notes = next;
+	}
+    }
+}
+
+
+/* Compute register info: lifetime, bb, and number of defs and uses.  */
+static void
+df_note_compute (bitmap all_blocks)
+{
+  unsigned int bb_index;
+  bitmap_iterator bi;
+  bitmap live = BITMAP_ALLOC (&df_bitmap_obstack);
+  bitmap do_not_gen = BITMAP_ALLOC (&df_bitmap_obstack);
+  bitmap artificial_uses = BITMAP_ALLOC (&df_bitmap_obstack);
+
+#ifdef REG_DEAD_DEBUGGING
+  if (dump_file)
+    print_rtl_with_bb (dump_file, get_insns());
+#endif
+
+  EXECUTE_IF_SET_IN_BITMAP (all_blocks, 0, bb_index, bi)
+  {
+    df_note_bb_compute (bb_index, live, do_not_gen, artificial_uses);
+  }
+
+  BITMAP_FREE (live);
+  BITMAP_FREE (do_not_gen);
+  BITMAP_FREE (artificial_uses);
+}
+
+
+/* Free all storage associated with the problem.  */
+
+static void
+df_note_free (void)
+{
+  free (df_note);
+}
+
+
+/* All of the information associated every instance of the problem.  */
+
+static struct df_problem problem_NOTE =
+{
+  DF_NOTE,                    /* Problem id.  */
+  DF_NONE,                    /* Direction.  */
+  df_note_alloc,              /* Allocate the problem specific data.  */
+  NULL,                       /* Reset global information.  */
+  NULL,                       /* Free basic block info.  */
+  df_note_compute,            /* 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_note_free,               /* Free all of the problem information.  */
+  df_note_free,               /* Remove this problem from the stack of dataflow problems.  */
+  NULL,                       /* Debugging.  */
+  NULL,                       /* Debugging start block.  */
+  NULL,                       /* Debugging end block.  */
+  NULL,                       /* Incremental solution verify start.  */
+  NULL,                       /* Incremental solution verify end.  */
+  &problem_LR,                /* Dependent problem.  */
+  TV_DF_NOTE,                 /* 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_note_add_problem (void)
+{
+  df_add_problem (&problem_NOTE);
+}
+
+
+
+
+/*----------------------------------------------------------------------------
+   Functions for simulating the effects of single insns.  
+
+   You can either simulate in the forwards direction, starting from
+   the top of a block or the backwards direction from the end of the
+   block.  The main difference is that if you go forwards, the uses
+   are examined first then the defs, and if you go backwards, the defs
+   are examined first then the uses.
+
+   If you start at the top of the block, use one of DF_LIVE_IN or
+   DF_LR_IN.  If you start at the bottom of the block use one of
+   DF_LIVE_OUT or DF_LR_OUT.  BE SURE TO PASS A COPY OF THESE SETS,
+   THEY WILL BE DESTROYED.
+----------------------------------------------------------------------------*/
+
+
+/* Find the set of DEFs for INSN.  */
+
+void
+df_simulate_find_defs (rtx insn, bitmap defs)
+{
+  df_ref *def_rec;
+  unsigned int uid = INSN_UID (insn);
+
+  for (def_rec = DF_INSN_UID_DEFS (uid); *def_rec; def_rec++)
+    {
+      df_ref def = *def_rec;
+      /* If the def is to only part of the reg, it does
+	 not kill the other defs that reach here.  */
+      if (!(DF_REF_FLAGS (def) & (DF_REF_PARTIAL | DF_REF_CONDITIONAL)))
+	bitmap_set_bit (defs, DF_REF_REGNO (def));
+    }
+}
+
+
+/* Simulate the effects of the defs of INSN on LIVE.  */
+
+void
+df_simulate_defs (rtx insn, bitmap live)
+{
+  df_ref *def_rec;
+  unsigned int uid = INSN_UID (insn);
+
+  for (def_rec = DF_INSN_UID_DEFS (uid); *def_rec; def_rec++)
+    {
+      df_ref def = *def_rec;
+      unsigned int dregno = DF_REF_REGNO (def);
+
+      /* If the def is to only part of the reg, it does
+	 not kill the other defs that reach here.  */
+      if (!(DF_REF_FLAGS (def) & (DF_REF_PARTIAL | DF_REF_CONDITIONAL)))
+	bitmap_clear_bit (live, dregno);
+    }
+}  
+
+
+/* Simulate the effects of the uses of INSN on LIVE.  */
+
+void 
+df_simulate_uses (rtx insn, bitmap live)
+{
+  df_ref *use_rec;
+  unsigned int uid = INSN_UID (insn);
+
+  for (use_rec = DF_INSN_UID_USES (uid); *use_rec; use_rec++)
+    {
+      df_ref use = *use_rec;
+      /* Add use to set of uses in this BB.  */
+      bitmap_set_bit (live, DF_REF_REGNO (use));
+    }
+}
+
+
+/* Add back the always live regs in BB to LIVE.  */
+
+static inline void
+df_simulate_fixup_sets (basic_block bb, bitmap live)
+{
+  /* These regs are considered always live so if they end up dying
+     because of some def, we need to bring the back again.  */
+  if (bb_has_eh_pred (bb))
+    bitmap_ior_into (live, df->eh_block_artificial_uses);
+  else
+    bitmap_ior_into (live, df->regular_block_artificial_uses);
+}
+
+
+/*----------------------------------------------------------------------------
+   The following three functions are used only for BACKWARDS scanning:
+   i.e. they process the defs before the uses.
+
+   df_simulate_initialize_backwards should be called first with a
+   bitvector copyied from the DF_LIVE_OUT or DF_LR_OUT.  Then
+   df_simulate_one_insn_backwards should be called for each insn in
+   the block, starting with the last on.  Finally,
+   df_simulate_finalize_backwards can be called to get a new value
+   of the sets at the top of the block (this is rarely used).
+   ----------------------------------------------------------------------------*/
+
+/* Apply the artificial uses and defs at the end of BB in a backwards
+   direction.  */
+
+void 
+df_simulate_initialize_backwards (basic_block bb, bitmap live)
+{
+  df_ref *def_rec;
+  df_ref *use_rec;
+  int bb_index = bb->index;
+  
+  for (def_rec = df_get_artificial_defs (bb_index); *def_rec; def_rec++)
+    {
+      df_ref def = *def_rec;
+      if ((DF_REF_FLAGS (def) & DF_REF_AT_TOP) == 0)
+	bitmap_clear_bit (live, DF_REF_REGNO (def));
+    }
+
+  for (use_rec = df_get_artificial_uses (bb_index); *use_rec; use_rec++)
+    {
+      df_ref use = *use_rec;
+      if ((DF_REF_FLAGS (use) & DF_REF_AT_TOP) == 0)
+	bitmap_set_bit (live, DF_REF_REGNO (use));
+    }
+}
+
+
+/* Simulate the backwards effects of INSN on the bitmap LIVE.  */
+
+void 
+df_simulate_one_insn_backwards (basic_block bb, rtx insn, bitmap live)
+{
+  if (! INSN_P (insn))
+    return;	
+  
+  df_simulate_defs (insn, live);
+  df_simulate_uses (insn, live);
+  df_simulate_fixup_sets (bb, live);
+}
+
+
+/* Apply the artificial uses and defs at the top of BB in a backwards
+   direction.  */
+
+void 
+df_simulate_finalize_backwards (basic_block bb, bitmap live)
+{
+  df_ref *def_rec;
+#ifdef EH_USES
+  df_ref *use_rec;
+#endif
+  int bb_index = bb->index;
+  
+  for (def_rec = df_get_artificial_defs (bb_index); *def_rec; def_rec++)
+    {
+      df_ref def = *def_rec;
+      if (DF_REF_FLAGS (def) & DF_REF_AT_TOP)
+	bitmap_clear_bit (live, DF_REF_REGNO (def));
+    }
+
+#ifdef EH_USES
+  for (use_rec = df_get_artificial_uses (bb_index); *use_rec; use_rec++)
+    {
+      df_ref use = *use_rec;
+      if (DF_REF_FLAGS (use) & DF_REF_AT_TOP)
+	bitmap_set_bit (live, DF_REF_REGNO (use));
+    }
+#endif
+}
+/*----------------------------------------------------------------------------
+   The following three functions are used only for FORWARDS scanning:
+   i.e. they process the defs and the REG_DEAD and REG_UNUSED notes.
+   Thus it is important to add the DF_NOTES problem to the stack of 
+   problems computed before using these functions.
+
+   df_simulate_initialize_forwards should be called first with a
+   bitvector copyied from the DF_LIVE_IN or DF_LR_IN.  Then
+   df_simulate_one_insn_forwards should be called for each insn in
+   the block, starting with the last on.  Finally,
+   df_simulate_finalize_forwards can be called to get a new value
+   of the sets at the bottom of the block (this is rarely used).
+   ----------------------------------------------------------------------------*/
+
+/* Apply the artificial uses and defs at the top of BB in a backwards
+   direction.  */
+
+void 
+df_simulate_initialize_forwards (basic_block bb, bitmap live)
+{
+  df_ref *def_rec;
+  int bb_index = bb->index;
+  
+  for (def_rec = df_get_artificial_defs (bb_index); *def_rec; def_rec++)
+    {
+      df_ref def = *def_rec;
+      if (DF_REF_FLAGS (def) & DF_REF_AT_TOP)
+	bitmap_clear_bit (live, DF_REF_REGNO (def));
+    }
+}
+
+/* Simulate the backwards effects of INSN on the bitmap LIVE.  */
+
+void 
+df_simulate_one_insn_forwards (basic_block bb, rtx insn, bitmap live)
+{
+  rtx link;
+  if (! INSN_P (insn))
+    return;	
+
+  /* Make sure that the DF_NOTES really is an active df problem.  */ 
+  gcc_assert (df_note);
+
+  df_simulate_defs (insn, live);
+
+  /* Clear all of the registers that go dead.  */
+  for (link = REG_NOTES (insn); link; link = XEXP (link, 1))
+    {
+      switch (REG_NOTE_KIND (link))
+	case REG_DEAD:
+	case REG_UNUSED:
+	{
+	  rtx reg = XEXP (link, 0);
+	  int regno = REGNO (reg);
+	  if (regno < FIRST_PSEUDO_REGISTER)
+	    {
+	      int n = hard_regno_nregs[regno][GET_MODE (reg)];
+	      while (--n >= 0)
+		bitmap_clear_bit (live, regno + n);
+	    }
+	  else 
+	    bitmap_clear_bit (live, regno);
+	  break;
+	default:
+	  break;
+	}
+    }
+  df_simulate_fixup_sets (bb, live);
+}
+
+
+/* Apply the artificial uses and defs at the end of BB in a backwards
+   direction.  */
+
+void 
+df_simulate_finalize_forwards (basic_block bb, bitmap live)
+{
+  df_ref *def_rec;
+  int bb_index = bb->index;
+  
+  for (def_rec = df_get_artificial_defs (bb_index); *def_rec; def_rec++)
+    {
+      df_ref def = *def_rec;
+      if ((DF_REF_FLAGS (def) & DF_REF_AT_TOP) == 0)
+	bitmap_clear_bit (live, DF_REF_REGNO (def));
+    }
+}
+
+