Update 4.8.1 to 4.8.3.

My previous drop was the wrong version. The platform mingw is
currently using 4.8.3, not 4.8.1 (not sure how I got that wrong).

From ftp://ftp.gnu.org/gnu/gcc/gcc-4.8.3/gcc-4.8.3.tar.bz2.

Bug: http://b/26523949
Change-Id: Id85f1bdcbbaf78c7d0b5a69e74c798a08f341c35

1 files changed, 4511 insertions, 0 deletions

diff --git a/gcc-4.8.3/gcc/df-problems.c b/gcc-4.8.3/gcc/df-problems.c
new file mode 100644
index 000000000..abe6958a0
--- /dev/null
+++ b/gcc-4.8.3/gcc/df-problems.c
@@ -0,0 +1,4511 @@
+/* Standard problems for dataflow support routines.
+   Copyright (C) 1999-2013 Free Software Foundation, Inc.
+   Originally contributed by Michael P. Hayes
+             (m.hayes@elec.canterbury.ac.nz, mhayes@redhat.com)
+   Major rewrite contributed by Danny Berlin (dberlin@dberlin.org)
+             and Kenneth Zadeck (zadeck@naturalbridge.com).
+
+This file is part of GCC.
+
+GCC is free software; you can redistribute it and/or modify it under
+the terms of the GNU General Public License as published by the Free
+Software Foundation; either version 3, or (at your option) any later
+version.
+
+GCC is distributed in the hope that it will be useful, but WITHOUT ANY
+WARRANTY; without even the implied warranty of MERCHANTABILITY or
+FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License
+for more details.
+
+You should have received a copy of the GNU General Public License
+along with GCC; see the file COPYING3.  If not see
+<http://www.gnu.org/licenses/>.  */
+
+#include "config.h"
+#include "system.h"
+#include "coretypes.h"
+#include "tm.h"
+#include "rtl.h"
+#include "tm_p.h"
+#include "insn-config.h"
+#include "recog.h"
+#include "function.h"
+#include "regs.h"
+#include "alloc-pool.h"
+#include "flags.h"
+#include "hard-reg-set.h"
+#include "basic-block.h"
+#include "sbitmap.h"
+#include "bitmap.h"
+#include "target.h"
+#include "timevar.h"
+#include "df.h"
+#include "except.h"
+#include "dce.h"
+#include "valtrack.h"
+#include "dumpfile.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.  */
+#define REG_DEAD_DEBUGGING 0
+
+#define DF_SPARSE_THRESHOLD 32
+
+static bitmap_head seen_in_block;
+static bitmap_head seen_in_insn;
+
+/*----------------------------------------------------------------------------
+   Utility functions.
+----------------------------------------------------------------------------*/
+
+/* Generic versions to get the void* version of the block info.  Only
+   used inside the problem instance vectors.  */
+
+/* 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'
+	       : (DF_REF_FLAGS (link->ref) & DF_REF_IN_NOTE) ? 'e' : '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");
+}
+
+
+/*----------------------------------------------------------------------------
+   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.
+
+   If the DF_RD_PRUNE_DEAD_DEFS changable flag is set, only DEFs reaching
+   existing uses are included in the global reaching DEFs set, or in other
+   words only DEFs that are still live.  This is a kind of pruned version
+   of the traditional reaching definitions problem that is much less
+   complex to compute and produces enough information to compute UD-chains.
+   In this context, live must be interpreted in the DF_LR sense: Uses that
+   are upward exposed but maybe not initialized on all paths through the
+   CFG.  For a USE that is not reached by a DEF on all paths, we still want
+   to make those DEFs that do reach the USE visible, and pruning based on
+   DF_LIVE would make that impossible.
+   ----------------------------------------------------------------------------*/
+
+/* 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_head sparse_invalidated_by_call;
+  /* The set of defs to regs invalidate by call for rd.  */
+  bitmap_head dense_invalidated_by_call;
+  /* An obstack for the bitmaps we need for this problem.  */
+  bitmap_obstack rd_bitmaps;
+};
+
+
+/* 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_clear (&bb_info->kill);
+      bitmap_clear (&bb_info->sparse_kill);
+      bitmap_clear (&bb_info->gen);
+      bitmap_clear (&bb_info->in);
+      bitmap_clear (&bb_info->out);
+    }
+}
+
+
+/* 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->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);
+      bitmap_initialize (&problem_data->sparse_invalidated_by_call,
+			 &problem_data->rd_bitmaps);
+      bitmap_initialize (&problem_data->dense_invalidated_by_call,
+			 &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);
+      
+      /* When bitmaps are already initialized, just clear them.  */
+      if (bb_info->kill.obstack)
+	{
+	  bitmap_clear (&bb_info->kill);
+	  bitmap_clear (&bb_info->sparse_kill);
+	  bitmap_clear (&bb_info->gen);
+	}
+      else
+	{
+	  bitmap_initialize (&bb_info->kill, &problem_data->rd_bitmaps);
+	  bitmap_initialize (&bb_info->sparse_kill, &problem_data->rd_bitmaps);
+	  bitmap_initialize (&bb_info->gen, &problem_data->rd_bitmaps);
+	  bitmap_initialize (&bb_info->in, &problem_data->rd_bitmaps);
+	  bitmap_initialize (&bb_info->out, &problem_data->rd_bitmaps);
+	}
+    }
+  df_rd->optional_p = true;
+}
+
+
+/* Add the effect of the top artificial defs of BB to the reaching definitions
+   bitmap LOCAL_RD.  */
+
+void
+df_rd_simulate_artificial_defs_at_top (basic_block bb, bitmap local_rd)
+{
+  int bb_index = bb->index;
+  df_ref *def_rec;
+  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 (local_rd,
+				DF_DEFS_BEGIN (dregno),
+				DF_DEFS_COUNT (dregno));
+	  bitmap_set_bit (local_rd, DF_REF_ID (def));
+	}
+    }
+}
+
+/* Add the effect of the defs of INSN to the reaching definitions bitmap
+   LOCAL_RD.  */
+
+void
+df_rd_simulate_one_insn (basic_block bb ATTRIBUTE_UNUSED, rtx insn,
+			 bitmap local_rd)
+{
+  unsigned uid = INSN_UID (insn);
+  df_ref *def_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);
+      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 (local_rd,
+				DF_DEFS_BEGIN (dregno),
+				DF_DEFS_COUNT (dregno));
+	  if (!(DF_REF_FLAGS (def)
+		& (DF_REF_MUST_CLOBBER | DF_REF_MAY_CLOBBER)))
+	    bitmap_set_bit (local_rd, DF_REF_ID (def));
+	}
+    }
+}
+
+/* Process a list of DEFs for df_rd_bb_local_compute.  This is a bit
+   more complicated than just simulating, because we must produce the
+   gen and kill sets and hence deal with the two possible representations
+   of kill sets.   */
+
+static void
+df_rd_bb_local_compute_process_def (struct df_rd_bb_info *bb_info,
+				    df_ref *def_rec,
+				    int 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;
+
+  bitmap_initialize (&seen_in_block, &df_bitmap_obstack);
+  bitmap_initialize (&seen_in_insn, &df_bitmap_obstack);
+
+  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 (! HARD_REGISTER_NUM_P (regno)
+	  || !(df->changeable_flags & DF_NO_HARD_REGS))
+	{
+	  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));
+	}
+    }
+
+  bitmap_clear (&seen_in_block);
+  bitmap_clear (&seen_in_insn);
+}
+
+
+/* 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 bool
+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;
+  bool changed = false;
+
+  if (e->flags & EDGE_FAKE)
+    return false;
+
+  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_head tmp;
+
+      bitmap_initialize (&tmp, &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));
+	}
+      changed |= bitmap_ior_into (op1, &tmp);
+      bitmap_clear (&tmp);
+      return changed;
+    }
+  else
+    return 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;
+  bool changed = false;
+
+  if (bitmap_empty_p (sparse_kill))
+    changed = bitmap_ior_and_compl (out, gen, in, kill);
+  else
+    {
+      struct df_rd_problem_data *problem_data;
+      bitmap_head 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;
+      bitmap_initialize (&tmp, &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_clear (out);
+	  bb_info->out = tmp;
+	}
+      else
+	bitmap_clear (&tmp);
+    }
+
+  if (df->changeable_flags & DF_RD_PRUNE_DEAD_DEFS)
+    {
+      /* Create a mask of DEFs for all registers live at the end of this
+	 basic block, and mask out DEFs of registers that are not live.
+	 Computing the mask looks costly, but the benefit of the pruning
+	 outweighs the cost.  */
+      struct df_rd_bb_info *bb_info = df_rd_get_bb_info (bb_index);
+      bitmap regs_live_out = &df_lr_get_bb_info (bb_index)->out;
+      bitmap live_defs = BITMAP_ALLOC (&df_bitmap_obstack);
+      unsigned int regno;
+      bitmap_iterator bi;
+
+      EXECUTE_IF_SET_IN_BITMAP (regs_live_out, 0, regno, bi)
+	bitmap_set_range (live_defs,
+			  DF_DEFS_BEGIN (regno),
+			  DF_DEFS_COUNT (regno));
+      changed |= bitmap_and_into (&bb_info->out, live_defs);
+      BITMAP_FREE (live_defs);
+    }
+
+  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)
+    {
+      bitmap_obstack_release (&problem_data->rd_bitmaps);
+
+      df_rd->block_info_size = 0;
+      free (df_rd->block_info);
+      df_rd->block_info = NULL;
+      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");
+
+  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);
+
+  fprintf (file, ";;  reg->defs[] map:\t");
+  for (regno = 0; regno < m; regno++)
+    if (DF_DEFS_COUNT (regno))
+      fprintf (file, "%d[%d,%d] ", regno,
+	       DF_DEFS_BEGIN (regno),
+	       DF_DEFS_BEGIN (regno) + DF_DEFS_COUNT (regno) - 1);
+  fprintf (file, "\n");
+}
+
+
+static void
+df_rd_dump_defs_set (bitmap defs_set, const char *prefix, FILE *file)
+{
+  bitmap_head tmp;
+  unsigned int regno;
+  unsigned int m = DF_REG_SIZE(df);
+  bool first_reg = true;
+
+  fprintf (file, "%s\t(%d) ", prefix, (int) bitmap_count_bits (defs_set));
+
+  bitmap_initialize (&tmp, &df_bitmap_obstack);
+  for (regno = 0; regno < m; regno++)
+    {
+      if (HARD_REGISTER_NUM_P (regno)
+	  && (df->changeable_flags & DF_NO_HARD_REGS))
+	continue;
+      bitmap_set_range (&tmp, DF_DEFS_BEGIN (regno), DF_DEFS_COUNT (regno));
+      bitmap_and_into (&tmp, defs_set);
+      if (! bitmap_empty_p (&tmp))
+	{
+	  bitmap_iterator bi;
+	  unsigned int ix;
+	  bool first_def = true;
+
+	  if (! first_reg)
+	    fprintf (file, ",");
+	  first_reg = false;
+
+	  fprintf (file, "%u[", regno);
+	  EXECUTE_IF_SET_IN_BITMAP (&tmp, 0, ix, bi)
+	    {
+	      fprintf (file, "%s%u", first_def ? "" : ",", ix);
+	      first_def = false;
+	    }
+	  fprintf (file, "]");
+	}
+      bitmap_clear (&tmp);
+    }
+
+  fprintf (file, "\n");
+  bitmap_clear (&tmp);
+}
+
+/* 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)
+    return;
+
+  df_rd_dump_defs_set (&bb_info->in, ";; rd  in  ", file);
+  df_rd_dump_defs_set (&bb_info->gen, ";; rd  gen ", file);
+  df_rd_dump_defs_set (&bb_info->kill, ";; rd  kill", file);
+}
+
+
+/* Debugging info at bottom 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)
+    return;
+
+  df_rd_dump_defs_set (&bb_info->out, ";; rd  out ", file);
+}
+
+/* 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,                       /* Debugging start insn.  */
+  NULL,                       /* Debugging end insn.  */
+  NULL,                       /* Incremental solution verify start.  */
+  NULL,                       /* Incremental solution verify end.  */
+  NULL,                       /* Dependent problem.  */
+  sizeof (struct df_rd_bb_info),/* Size of entry of block_info array.  */
+  TV_DF_RD,                   /* Timing variable.  */
+  true                        /* Reset blocks on dropping out of blocks_to_analyze.  */
+};
+
+
+
+/* Create a new RD instance and add it to the existing instance
+   of DF.  */
+
+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_head *in;
+  bitmap_head *out;
+  /* An obstack for the bitmaps we need for this problem.  */
+  bitmap_obstack lr_bitmaps;
+};
+
+/* 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_clear (&bb_info->use);
+      bitmap_clear (&bb_info->def);
+      bitmap_clear (&bb_info->in);
+      bitmap_clear (&bb_info->out);
+    }
+}
+
+
+/* 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;
+  struct df_lr_problem_data *problem_data;
+
+  df_grow_bb_info (df_lr);
+  if (df_lr->problem_data)
+    problem_data = (struct df_lr_problem_data *) df_lr->problem_data;
+  else
+    {
+      problem_data = XNEW (struct df_lr_problem_data);
+      df_lr->problem_data = problem_data;
+
+      problem_data->out = NULL;
+      problem_data->in = NULL;
+      bitmap_obstack_initialize (&problem_data->lr_bitmaps);
+    }
+
+  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);
+      
+      /* When bitmaps are already initialized, just clear them.  */
+      if (bb_info->use.obstack)
+	{
+	  bitmap_clear (&bb_info->def);
+	  bitmap_clear (&bb_info->use);
+	}
+      else
+	{
+	  bitmap_initialize (&bb_info->use, &problem_data->lr_bitmaps);
+	  bitmap_initialize (&bb_info->def, &problem_data->lr_bitmaps);
+	  bitmap_initialize (&bb_info->in, &problem_data->lr_bitmaps);
+	  bitmap_initialize (&bb_info->out, &problem_data->lr_bitmaps);
+	}
+    }
+
+  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 (!NONDEBUG_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, i;
+  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);
+
+  /* Global regs are always live, too.  */
+  for (i = 0; i < FIRST_PSEUDO_REGISTER; i++)
+    if (global_regs[i])
+      bitmap_set_bit (&df->hardware_regs_used, i);
+
+  /* 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)
+    {
+      unsigned int pic_offset_table_regnum = PIC_OFFSET_TABLE_REGNUM;
+      /* 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 (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 bool
+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;
+  bool changed = false;
+
+  /* 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)
+    changed = bitmap_ior_and_compl_into (op1, op2, regs_invalidated_by_call_regset);
+  else
+    changed = bitmap_ior_into (op1, op2);
+
+  changed |= bitmap_ior_into (op1, &df->hardware_regs_used);
+  return changed;
+}
+
+
+/* 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)
+{
+  struct df_lr_problem_data *problem_data
+    = (struct df_lr_problem_data *) df_lr->problem_data;
+  if (df_lr->block_info)
+    {
+
+      df_lr->block_info_size = 0;
+      free (df_lr->block_info);
+      df_lr->block_info = NULL;
+      bitmap_obstack_release (&problem_data->lr_bitmaps);
+      free (df_lr->problem_data);
+      df_lr->problem_data = NULL;
+    }
+
+  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)
+    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;
+      if (problem_data->in)
+	{
+      	  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)
+    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;
+      if (problem_data->out)
+	{
+          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)
+    return;
+
+  /* Set it true so that the solution is recomputed.  */
+  df_lr->solutions_dirty = true;
+
+  problem_data = (struct df_lr_problem_data *)df_lr->problem_data;
+  problem_data->in = XNEWVEC (bitmap_head, last_basic_block);
+  problem_data->out = XNEWVEC (bitmap_head, last_basic_block);
+
+  FOR_ALL_BB (bb)
+    {
+      bitmap_initialize (&problem_data->in[bb->index], &problem_data->lr_bitmaps);
+      bitmap_initialize (&problem_data->out[bb->index], &problem_data->lr_bitmaps);
+      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;
+
+  problem_data = (struct df_lr_problem_data *)df_lr->problem_data;
+
+  if (!problem_data->out)
+    return;
+
+  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_clear (&problem_data->in[bb->index]);
+      bitmap_clear (&problem_data->out[bb->index]);
+    }
+
+  free (problem_data->in);
+  free (problem_data->out);
+  problem_data->in = NULL;
+  problem_data->out = 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.  */
+  NULL,                       /* Debugging start insn.  */
+  NULL,                       /* Debugging end insn.  */
+  df_lr_verify_solution_start,/* Incremental solution verify start.  */
+  df_lr_verify_solution_end,  /* Incremental solution verify end.  */
+  NULL,                       /* Dependent problem.  */
+  sizeof (struct df_lr_bb_info),/* Size of entry of block_info array.  */
+  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 (&df_bitmap_obstack);
+}
+
+
+/* Verify that all of the lr related info is consistent and
+   correct.  */
+
+void
+df_lr_verify_transfer_functions (void)
+{
+  basic_block bb;
+  bitmap_head saved_def;
+  bitmap_head saved_use;
+  bitmap_head all_blocks;
+
+  if (!df)
+    return;
+
+  bitmap_initialize (&saved_def, &bitmap_default_obstack); 
+  bitmap_initialize (&saved_use, &bitmap_default_obstack);
+  bitmap_initialize (&all_blocks, &bitmap_default_obstack);
+
+  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_clear (&saved_def);
+  bitmap_clear (&saved_use);
+  bitmap_clear (&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_head *in;
+  bitmap_head *out;
+  /* An obstack for the bitmaps we need for this problem.  */
+  bitmap_obstack live_bitmaps;
+};
+
+/* 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_head df_live_scratch;
+
+
+/* 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_clear (&bb_info->gen);
+      bitmap_clear (&bb_info->kill);
+      bitmap_clear (&bb_info->in);
+      bitmap_clear (&bb_info->out);
+    }
+}
+
+
+/* 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;
+  struct df_live_problem_data *problem_data;
+
+  if (df_live->problem_data)
+    problem_data = (struct df_live_problem_data *) df_live->problem_data;
+  else
+    {
+      problem_data = XNEW (struct df_live_problem_data);
+      df_live->problem_data = problem_data;
+
+      problem_data->out = NULL;
+      problem_data->in = NULL;
+      bitmap_obstack_initialize (&problem_data->live_bitmaps);
+      bitmap_initialize (&df_live_scratch, &problem_data->live_bitmaps);
+    }
+
+  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);
+      
+      /* When bitmaps are already initialized, just clear them.  */
+      if (bb_info->kill.obstack)
+	{
+	  bitmap_clear (&bb_info->kill);
+	  bitmap_clear (&bb_info->gen);
+	}
+      else
+	{
+	  bitmap_initialize (&bb_info->kill, &problem_data->live_bitmaps);
+	  bitmap_initialize (&bb_info->gen, &problem_data->live_bitmaps);
+	  bitmap_initialize (&bb_info->in, &problem_data->live_bitmaps);
+	  bitmap_initialize (&bb_info->out, &problem_data->live_bitmaps);
+	}
+    }
+  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 bool
+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 false;
+
+  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 whether 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)
+{
+  struct df_live_problem_data *problem_data
+    = (struct df_live_problem_data *) df_live->problem_data;
+  if (df_live->block_info)
+    {
+      df_live->block_info_size = 0;
+      free (df_live->block_info);
+      df_live->block_info = NULL;
+      bitmap_clear (&df_live_scratch);
+      bitmap_obstack_release (&problem_data->live_bitmaps);
+      free (problem_data);
+      df_live->problem_data = NULL;
+    }
+  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)
+    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;
+      if (problem_data->in)
+	{
+	  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)
+    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;
+      if (problem_data->out)
+	{
+	  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)
+    return;
+
+  /* Set it true so that the solution is recomputed.  */
+  df_live->solutions_dirty = true;
+
+  problem_data = (struct df_live_problem_data *)df_live->problem_data;
+  problem_data->in = XNEWVEC (bitmap_head, last_basic_block);
+  problem_data->out = XNEWVEC (bitmap_head, last_basic_block);
+
+  FOR_ALL_BB (bb)
+    {
+      bitmap_initialize (&problem_data->in[bb->index], &problem_data->live_bitmaps);
+      bitmap_initialize (&problem_data->out[bb->index], &problem_data->live_bitmaps);
+      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;
+
+  problem_data = (struct df_live_problem_data *)df_live->problem_data;
+  if (!problem_data->out)
+    return;
+
+  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_clear (&problem_data->in[bb->index]);
+      bitmap_clear (&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.  */
+  NULL,                         /* Debugging start insn.  */
+  NULL,                         /* Debugging end insn.  */
+  df_live_verify_solution_start,/* Incremental solution verify start.  */
+  df_live_verify_solution_end,  /* Incremental solution verify end.  */
+  &problem_LR,                  /* Dependent problem.  */
+  sizeof (struct df_live_bb_info),/* Size of entry of block_info array.  */
+  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 (&df_bitmap_obstack);
+}
+
+
+/* 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_head saved_gen;
+  bitmap_head saved_kill;
+  bitmap_head all_blocks;
+
+  if (!df)
+    return;
+
+  bitmap_initialize (&saved_gen, &bitmap_default_obstack);
+  bitmap_initialize (&saved_kill, &bitmap_default_obstack);
+  bitmap_initialize (&all_blocks, &bitmap_default_obstack);
+
+  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_clear (&saved_gen);
+  bitmap_clear (&saved_kill);
+  bitmap_clear (&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,
+				int 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_head cpy;
+
+  bitmap_initialize (&cpy, &bitmap_default_obstack);
+  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
+
+  df_rd_simulate_artificial_defs_at_top (bb, &cpy);
+
+  /* Process the regular instructions next.  */
+  FOR_BB_INSNS (bb, insn)
+    if (INSN_P (insn))
+      {
+        unsigned int uid = INSN_UID (insn);
+
+        /* First 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.  */
+        df_rd_simulate_one_insn (bb, insn, &cpy);
+      }
+
+  /* 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_clear (&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_bb_dump (basic_block bb, FILE *file, bool top)
+{
+  /* Artificials are only hard regs.  */
+  if (df->changeable_flags & DF_NO_HARD_REGS)
+    return;
+  if (df_chain_problem_p (DF_UD_CHAIN))
+    {
+      fprintf (file,
+	       ";;  UD chains for artificial uses at %s\n",
+	       top ? "top" : "bottom");
+      df_ref *use_rec = df_get_artificial_uses (bb->index);
+      if (*use_rec)
+	{
+	  while (*use_rec)
+	    {
+	      df_ref use = *use_rec;
+	      if ((top && (DF_REF_FLAGS (use) & DF_REF_AT_TOP))
+		  || (!top && !(DF_REF_FLAGS (use) & DF_REF_AT_TOP)))
+		{
+		  fprintf (file, ";;   reg %d ", DF_REF_REGNO (use));
+		  df_chain_dump (DF_REF_CHAIN (use), file);
+		  fprintf (file, "\n");
+		}
+	      use_rec++;
+	    }
+	}
+    }
+  if (df_chain_problem_p (DF_DU_CHAIN))
+    {
+      fprintf (file,
+	       ";;  DU chains for artificial defs at %s\n",
+	       top ? "top" : "bottom");
+      df_ref *def_rec = df_get_artificial_defs (bb->index);
+      if (*def_rec)
+	{
+	  while (*def_rec)
+	    {
+	      df_ref def = *def_rec;
+
+	      if ((top && (DF_REF_FLAGS (def) & DF_REF_AT_TOP))
+		  || (!top && !(DF_REF_FLAGS (def) & DF_REF_AT_TOP)))
+		{
+		  fprintf (file, ";;   reg %d ", DF_REF_REGNO (def));
+		  df_chain_dump (DF_REF_CHAIN (def), file);
+		  fprintf (file, "\n");
+		}
+	      def_rec++;
+	    }
+	}
+    }
+}
+
+static void
+df_chain_top_dump (basic_block bb, FILE *file)
+{
+  df_chain_bb_dump (bb, file, /*top=*/true);
+}
+
+static void
+df_chain_bottom_dump (basic_block bb, FILE *file)
+{
+  df_chain_bb_dump (bb, file, /*top=*/false);
+}
+
+static void
+df_chain_insn_top_dump (const_rtx insn, FILE *file)
+{
+  if (df_chain_problem_p (DF_UD_CHAIN) && INSN_P (insn))
+    {
+      struct df_insn_info *insn_info = DF_INSN_INFO_GET (insn);
+      df_ref *use_rec = DF_INSN_INFO_USES (insn_info);
+      df_ref *eq_use_rec = DF_INSN_INFO_EQ_USES (insn_info);
+      fprintf (file, ";;   UD chains for insn luid %d uid %d\n",
+	       DF_INSN_INFO_LUID (insn_info), INSN_UID (insn));
+      if (*use_rec || *eq_use_rec)
+	{
+	  while (*use_rec)
+	    {
+	      df_ref use = *use_rec;
+	      if (! HARD_REGISTER_NUM_P (DF_REF_REGNO (use))
+		  || !(df->changeable_flags & DF_NO_HARD_REGS))
+		{
+		  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;
+	      if (! HARD_REGISTER_NUM_P (DF_REF_REGNO (use))
+		  || !(df->changeable_flags & DF_NO_HARD_REGS))
+		{
+		  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 void
+df_chain_insn_bottom_dump (const_rtx insn, FILE *file)
+{
+  if (df_chain_problem_p (DF_DU_CHAIN) && INSN_P (insn))
+    {
+      struct df_insn_info *insn_info = DF_INSN_INFO_GET (insn);
+      df_ref *def_rec = DF_INSN_INFO_DEFS (insn_info);
+      fprintf (file, ";;   DU chains for insn luid %d uid %d\n",
+	       DF_INSN_INFO_LUID (insn_info), INSN_UID (insn));
+      if (*def_rec)
+	{
+	  while (*def_rec)
+	    {
+	      df_ref def = *def_rec;
+	      if (! HARD_REGISTER_NUM_P (DF_REF_REGNO (def))
+		  || !(df->changeable_flags & DF_NO_HARD_REGS))
+		{
+		  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++;
+	    }
+	}
+      fprintf (file, "\n");
+    }
+}
+
+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.  */
+  df_chain_insn_top_dump,     /* Debugging start insn.  */
+  df_chain_insn_bottom_dump,  /* Debugging end insn.  */
+  NULL,                       /* Incremental solution verify start.  */
+  NULL,                       /* Incremental solution verify end.  */
+  &problem_RD,                /* Dependent problem.  */
+  sizeof (struct df_scan_bb_info),/* Size of entry of block_info array.  */
+  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 (unsigned int chain_flags)
+{
+  df_add_problem (&problem_CHAIN);
+  df_chain->local_flags = chain_flags;
+  df_chain->out_of_date_transfer_functions = BITMAP_ALLOC (&df_bitmap_obstack);
+}
+
+#undef df_chain_problem_p
+
+
+/*----------------------------------------------------------------------------
+   WORD 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.  We only track pseudo registers that have a
+   size of 2 * UNITS_PER_WORD; bitmaps are indexed by 2 * regno and
+   contain two bits corresponding to each of the subwords.
+
+   ----------------------------------------------------------------------------*/
+
+/* Private data used to verify the solution for this problem.  */
+struct df_word_lr_problem_data
+{
+  /* An obstack for the bitmaps we need for this problem.  */
+  bitmap_obstack word_lr_bitmaps;
+};
+
+
+/* Free basic block info.  */
+
+static void
+df_word_lr_free_bb_info (basic_block bb ATTRIBUTE_UNUSED,
+			 void *vbb_info)
+{
+  struct df_word_lr_bb_info *bb_info = (struct df_word_lr_bb_info *) vbb_info;
+  if (bb_info)
+    {
+      bitmap_clear (&bb_info->use);
+      bitmap_clear (&bb_info->def);
+      bitmap_clear (&bb_info->in);
+      bitmap_clear (&bb_info->out);
+    }
+}
+
+
+/* Allocate or reset bitmaps for DF_WORD_LR blocks. The solution bits are
+   not touched unless the block is new.  */
+
+static void
+df_word_lr_alloc (bitmap all_blocks ATTRIBUTE_UNUSED)
+{
+  unsigned int bb_index;
+  bitmap_iterator bi;
+  basic_block bb;
+  struct df_word_lr_problem_data *problem_data
+    = XNEW (struct df_word_lr_problem_data);
+
+  df_word_lr->problem_data = problem_data;
+
+  df_grow_bb_info (df_word_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->word_lr_bitmaps);
+
+  FOR_EACH_BB (bb)
+    bitmap_set_bit (df_word_lr->out_of_date_transfer_functions, bb->index);
+
+  bitmap_set_bit (df_word_lr->out_of_date_transfer_functions, ENTRY_BLOCK);
+  bitmap_set_bit (df_word_lr->out_of_date_transfer_functions, EXIT_BLOCK);
+
+  EXECUTE_IF_SET_IN_BITMAP (df_word_lr->out_of_date_transfer_functions, 0, bb_index, bi)
+    {
+      struct df_word_lr_bb_info *bb_info = df_word_lr_get_bb_info (bb_index);
+      
+      /* When bitmaps are already initialized, just clear them.  */
+      if (bb_info->use.obstack)
+	{
+	  bitmap_clear (&bb_info->def);
+	  bitmap_clear (&bb_info->use);
+	}
+      else
+	{
+	  bitmap_initialize (&bb_info->use, &problem_data->word_lr_bitmaps);
+	  bitmap_initialize (&bb_info->def, &problem_data->word_lr_bitmaps);
+	  bitmap_initialize (&bb_info->in, &problem_data->word_lr_bitmaps);
+	  bitmap_initialize (&bb_info->out, &problem_data->word_lr_bitmaps);
+	}
+    }
+
+  df_word_lr->optional_p = true;
+}
+
+
+/* Reset the global solution for recalculation.  */
+
+static void
+df_word_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_word_lr_bb_info *bb_info = df_word_lr_get_bb_info (bb_index);
+      gcc_assert (bb_info);
+      bitmap_clear (&bb_info->in);
+      bitmap_clear (&bb_info->out);
+    }
+}
+
+/* Examine REF, and if it is for a reg we're interested in, set or
+   clear the bits corresponding to its subwords from the bitmap
+   according to IS_SET.  LIVE is the bitmap we should update.  We do
+   not track hard regs or pseudos of any size other than 2 *
+   UNITS_PER_WORD.
+   We return true if we changed the bitmap, or if we encountered a register
+   we're not tracking.  */
+
+bool
+df_word_lr_mark_ref (df_ref ref, bool is_set, regset live)
+{
+  rtx orig_reg = DF_REF_REG (ref);
+  rtx reg = orig_reg;
+  enum machine_mode reg_mode;
+  unsigned regno;
+  /* Left at -1 for whole accesses.  */
+  int which_subword = -1;
+  bool changed = false;
+
+  if (GET_CODE (reg) == SUBREG)
+    reg = SUBREG_REG (orig_reg);
+  regno = REGNO (reg);
+  reg_mode = GET_MODE (reg);
+  if (regno < FIRST_PSEUDO_REGISTER
+      || GET_MODE_SIZE (reg_mode) != 2 * UNITS_PER_WORD)
+    return true;
+
+  if (GET_CODE (orig_reg) == SUBREG
+      && df_read_modify_subreg_p (orig_reg))
+    {
+      gcc_assert (DF_REF_FLAGS_IS_SET (ref, DF_REF_PARTIAL));
+      if (subreg_lowpart_p (orig_reg))
+	which_subword = 0;
+      else
+	which_subword = 1;
+    }
+  if (is_set)
+    {
+      if (which_subword != 1)
+	changed |= bitmap_set_bit (live, regno * 2);
+      if (which_subword != 0)
+	changed |= bitmap_set_bit (live, regno * 2 + 1);
+    }
+  else
+    {
+      if (which_subword != 1)
+	changed |= bitmap_clear_bit (live, regno * 2);
+      if (which_subword != 0)
+	changed |= bitmap_clear_bit (live, regno * 2 + 1);
+    }
+  return changed;
+}
+
+/* Compute local live register info for basic block BB.  */
+
+static void
+df_word_lr_bb_local_compute (unsigned int bb_index)
+{
+  basic_block bb = BASIC_BLOCK (bb_index);
+  struct df_word_lr_bb_info *bb_info = df_word_lr_get_bb_info (bb_index);
+  rtx insn;
+  df_ref *def_rec;
+  df_ref *use_rec;
+
+  /* Ensure that artificial refs don't contain references to pseudos.  */
+  for (def_rec = df_get_artificial_defs (bb_index); *def_rec; def_rec++)
+    {
+      df_ref def = *def_rec;
+      gcc_assert (DF_REF_REGNO (def) < FIRST_PSEUDO_REGISTER);
+    }
+
+  for (use_rec = df_get_artificial_uses (bb_index); *use_rec; use_rec++)
+    {
+      df_ref use = *use_rec;
+      gcc_assert (DF_REF_REGNO (use) < FIRST_PSEUDO_REGISTER);
+    }
+
+  FOR_BB_INSNS_REVERSE (bb, insn)
+    {
+      unsigned int uid = INSN_UID (insn);
+
+      if (!NONDEBUG_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)))
+	    {
+	      df_word_lr_mark_ref (def, true, &bb_info->def);
+	      df_word_lr_mark_ref (def, false, &bb_info->use);
+	    }
+	}
+      for (use_rec = DF_INSN_UID_USES (uid); *use_rec; use_rec++)
+	{
+	  df_ref use = *use_rec;
+	  df_word_lr_mark_ref (use, true, &bb_info->use);
+	}
+    }
+}
+
+
+/* Compute local live register info for each basic block within BLOCKS.  */
+
+static void
+df_word_lr_local_compute (bitmap all_blocks ATTRIBUTE_UNUSED)
+{
+  unsigned int bb_index;
+  bitmap_iterator bi;
+
+  EXECUTE_IF_SET_IN_BITMAP (df_word_lr->out_of_date_transfer_functions, 0, bb_index, bi)
+    {
+      if (bb_index == EXIT_BLOCK)
+	{
+	  unsigned regno;
+	  bitmap_iterator bi;
+	  EXECUTE_IF_SET_IN_BITMAP (df->exit_block_uses, FIRST_PSEUDO_REGISTER,
+				    regno, bi)
+	    gcc_unreachable ();
+	}
+      else
+	df_word_lr_bb_local_compute (bb_index);
+    }
+
+  bitmap_clear (df_word_lr->out_of_date_transfer_functions);
+}
+
+
+/* Initialize the solution vectors.  */
+
+static void
+df_word_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_word_lr_bb_info *bb_info = df_word_lr_get_bb_info (bb_index);
+      bitmap_copy (&bb_info->in, &bb_info->use);
+      bitmap_clear (&bb_info->out);
+    }
+}
+
+
+/* Confluence function that ignores fake edges.  */
+
+static bool
+df_word_lr_confluence_n (edge e)
+{
+  bitmap op1 = &df_word_lr_get_bb_info (e->src->index)->out;
+  bitmap op2 = &df_word_lr_get_bb_info (e->dest->index)->in;
+
+  return bitmap_ior_into (op1, op2);
+}
+
+
+/* Transfer function.  */
+
+static bool
+df_word_lr_transfer_function (int bb_index)
+{
+  struct df_word_lr_bb_info *bb_info = df_word_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_word_lr_free (void)
+{
+  struct df_word_lr_problem_data *problem_data
+    = (struct df_word_lr_problem_data *)df_word_lr->problem_data;
+
+  if (df_word_lr->block_info)
+    {
+      df_word_lr->block_info_size = 0;
+      free (df_word_lr->block_info);
+      df_word_lr->block_info = NULL;
+    }
+
+  BITMAP_FREE (df_word_lr->out_of_date_transfer_functions);
+  bitmap_obstack_release (&problem_data->word_lr_bitmaps);
+  free (problem_data);
+  free (df_word_lr);
+}
+
+
+/* Debugging info at top of bb.  */
+
+static void
+df_word_lr_top_dump (basic_block bb, FILE *file)
+{
+  struct df_word_lr_bb_info *bb_info = df_word_lr_get_bb_info (bb->index);
+  if (!bb_info)
+    return;
+
+  fprintf (file, ";; blr  in  \t");
+  df_print_word_regset (file, &bb_info->in);
+  fprintf (file, ";; blr  use \t");
+  df_print_word_regset (file, &bb_info->use);
+  fprintf (file, ";; blr  def \t");
+  df_print_word_regset (file, &bb_info->def);
+}
+
+
+/* Debugging info at bottom of bb.  */
+
+static void
+df_word_lr_bottom_dump (basic_block bb, FILE *file)
+{
+  struct df_word_lr_bb_info *bb_info = df_word_lr_get_bb_info (bb->index);
+  if (!bb_info)
+    return;
+
+  fprintf (file, ";; blr  out \t");
+  df_print_word_regset (file, &bb_info->out);
+}
+
+
+/* All of the information associated with every instance of the problem.  */
+
+static struct df_problem problem_WORD_LR =
+{
+  DF_WORD_LR,                      /* Problem id.  */
+  DF_BACKWARD,                     /* Direction.  */
+  df_word_lr_alloc,                /* Allocate the problem specific data.  */
+  df_word_lr_reset,                /* Reset global information.  */
+  df_word_lr_free_bb_info,         /* Free basic block info.  */
+  df_word_lr_local_compute,        /* Local compute function.  */
+  df_word_lr_init,                 /* Init the solution specific data.  */
+  df_worklist_dataflow,            /* Worklist solver.  */
+  NULL,                            /* Confluence operator 0.  */
+  df_word_lr_confluence_n,         /* Confluence operator n.  */
+  df_word_lr_transfer_function,    /* Transfer function.  */
+  NULL,                            /* Finalize function.  */
+  df_word_lr_free,                 /* Free all of the problem information.  */
+  df_word_lr_free,                 /* Remove this problem from the stack of dataflow problems.  */
+  NULL,                            /* Debugging.  */
+  df_word_lr_top_dump,             /* Debugging start block.  */
+  df_word_lr_bottom_dump,          /* Debugging end block.  */
+  NULL,                            /* Debugging start insn.  */
+  NULL,                            /* Debugging end insn.  */
+  NULL,                            /* Incremental solution verify start.  */
+  NULL,                            /* Incremental solution verify end.  */
+  NULL,                            /* Dependent problem.  */
+  sizeof (struct df_word_lr_bb_info),/* Size of entry of block_info array.  */
+  TV_DF_WORD_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_word_lr_add_problem (void)
+{
+  df_add_problem (&problem_WORD_LR);
+  /* These will be initialized when df_scan_blocks processes each
+     block.  */
+  df_word_lr->out_of_date_transfer_functions = BITMAP_ALLOC (&df_bitmap_obstack);
+}
+
+
+/* Simulate the effects of the defs of INSN on LIVE.  Return true if we changed
+   any bits, which is used by the caller to determine whether a set is
+   necessary.  We also return true if there are other reasons not to delete
+   an insn.  */
+
+bool
+df_word_lr_simulate_defs (rtx insn, bitmap live)
+{
+  bool changed = false;
+  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 (DF_REF_FLAGS (def) & DF_REF_CONDITIONAL)
+	changed = true;
+      else
+	changed |= df_word_lr_mark_ref (*def_rec, false, live);
+    }
+  return changed;
+}
+
+
+/* Simulate the effects of the uses of INSN on LIVE.  */
+
+void
+df_word_lr_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_word_lr_mark_ref (*use_rec, true, live);
+}
+
+/*----------------------------------------------------------------------------
+   This problem computes REG_DEAD and REG_UNUSED notes.
+   ----------------------------------------------------------------------------*/
+
+static void
+df_note_alloc (bitmap all_blocks ATTRIBUTE_UNUSED)
+{
+  df_note->optional_p = true;
+}
+
+/* This is only used if REG_DEAD_DEBUGGING is in effect.  */
+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");
+    }
+}
+
+
+/* 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.  */
+
+static void
+df_remove_dead_and_unused_notes (rtx insn)
+{
+  rtx *pprev = &REG_NOTES (insn);
+  rtx link = *pprev;
+
+  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);
+	      if (REG_DEAD_DEBUGGING)
+		df_print_note ("deleting: ", insn, link);
+	      free_EXPR_LIST_node (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);
+	      if (REG_DEAD_DEBUGGING)
+		df_print_note ("deleting: ", insn, link);
+	      free_EXPR_LIST_node (link);
+	      *pprev = link = next;
+	    }
+	  break;
+
+	default:
+	  pprev = &XEXP (link, 1);
+	  link = *pprev;
+	  break;
+	}
+    }
+}
+
+/* Remove REG_EQUAL/REG_EQUIV notes referring to dead pseudos using LIVE
+   as the bitmap of currently live registers.  */
+
+static void
+df_remove_dead_eq_notes (rtx insn, bitmap live)
+{
+  rtx *pprev = &REG_NOTES (insn);
+  rtx link = *pprev;
+
+  while (link)
+    {
+      switch (REG_NOTE_KIND (link))
+	{
+	case REG_EQUAL:
+	case REG_EQUIV:
+	  {
+	    /* Remove the notes that refer to dead registers.  As we have at most
+	       one REG_EQUAL/EQUIV note, all of EQ_USES will refer to this note
+	       so we need to purge the complete EQ_USES vector when removing
+	       the note using df_notes_rescan.  */
+	    df_ref *use_rec;
+	    bool deleted = false;
+
+	    for (use_rec = DF_INSN_EQ_USES (insn); *use_rec; use_rec++)
+	      {
+		df_ref use = *use_rec;
+		if (DF_REF_REGNO (use) > FIRST_PSEUDO_REGISTER
+		    && DF_REF_LOC (use)
+		    && (DF_REF_FLAGS (use) & DF_REF_IN_NOTE)
+		    && ! bitmap_bit_p (live, DF_REF_REGNO (use))
+		    && loc_mentioned_in_p (DF_REF_LOC (use), XEXP (link, 0)))
+		  {
+		    deleted = true;
+		    break;
+		  }
+	      }
+	    if (deleted)
+	      {
+		rtx next;
+		if (REG_DEAD_DEBUGGING)
+		  df_print_note ("deleting: ", insn, link);
+		next = XEXP (link, 1);
+		free_EXPR_LIST_node (link);
+		*pprev = link = next;
+		df_notes_rescan (insn);
+	      }
+	    else
+	      {
+		pprev = &XEXP (link, 1);
+		link = *pprev;
+	      }
+	    break;
+	  }
+
+	default:
+	  pprev = &XEXP (link, 1);
+	  link = *pprev;
+	  break;
+	}
+    }
+}
+
+/* Set a NOTE_TYPE note for REG in INSN.  */
+
+static inline void
+df_set_note (enum reg_note note_type, rtx insn, rtx reg)
+{
+  gcc_checking_assert (!DEBUG_INSN_P (insn));
+  add_reg_note (insn, note_type, reg);
+}
+
+/* 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 void
+df_set_unused_notes_for_mw (rtx insn, struct df_mw_hardreg *mws,
+			    bitmap live, bitmap do_not_gen,
+			    bitmap artificial_uses,
+			    struct dead_debug_local *debug)
+{
+  unsigned int r;
+
+  if (REG_DEAD_DEBUGGING && dump_file)
+    fprintf (dump_file, "mw_set_unused looking at mws[%d..%d]\n",
+	     mws->start_regno, mws->end_regno);
+
+  if (df_whole_mw_reg_unused_p (mws, live, artificial_uses))
+    {
+      unsigned int regno = mws->start_regno;
+      df_set_note (REG_UNUSED, insn, mws->mw_reg);
+      dead_debug_insert_temp (debug, regno, insn, DEBUG_TEMP_AFTER_WITH_REG);
+
+      if (REG_DEAD_DEBUGGING)
+	df_print_note ("adding 1: ", insn, REG_NOTES (insn));
+
+      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))
+	  {
+	    df_set_note (REG_UNUSED, insn, regno_reg_rtx[r]);
+	    dead_debug_insert_temp (debug, r, insn, DEBUG_TEMP_AFTER_WITH_REG);
+	    if (REG_DEAD_DEBUGGING)
+	      df_print_note ("adding 2: ", insn, REG_NOTES (insn));
+	  }
+	bitmap_set_bit (do_not_gen, r);
+      }
+}
+
+
+/* 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 void
+df_set_dead_notes_for_mw (rtx insn, struct df_mw_hardreg *mws,
+			  bitmap live, bitmap do_not_gen,
+			  bitmap artificial_uses, bool *added_notes_p)
+{
+  unsigned int r;
+  bool is_debug = *added_notes_p;
+
+  *added_notes_p = false;
+
+  if (REG_DEAD_DEBUGGING && 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);
+    }
+
+  if (df_whole_mw_reg_dead_p (mws, live, artificial_uses, do_not_gen))
+    {
+      if (is_debug)
+	{
+	  *added_notes_p = true;
+	  return;
+	}
+      /* Add a dead note for the entire multi word register.  */
+      df_set_note (REG_DEAD, insn, mws->mw_reg);
+      if (REG_DEAD_DEBUGGING)
+	df_print_note ("adding 1: ", insn, REG_NOTES (insn));
+    }
+  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))
+	  {
+	    if (is_debug)
+	      {
+		*added_notes_p = true;
+		return;
+	      }
+	    df_set_note (REG_DEAD, insn, regno_reg_rtx[r]);
+	    if (REG_DEAD_DEBUGGING)
+	      df_print_note ("adding 2: ", insn, REG_NOTES (insn));
+	  }
+    }
+  return;
+}
+
+
+/* Create a REG_UNUSED note if necessary for DEF in INSN updating
+   LIVE.  Do not generate notes for registers in ARTIFICIAL_USES.  */
+
+static void
+df_create_unused_note (rtx insn, df_ref def,
+		       bitmap live, bitmap artificial_uses,
+		       struct dead_debug_local *debug)
+{
+  unsigned int dregno = DF_REF_REGNO (def);
+
+  if (REG_DEAD_DEBUGGING && dump_file)
+    {
+      fprintf (dump_file, "  regular looking at def ");
+      df_ref_debug (def, dump_file);
+    }
+
+  if (!((DF_REF_FLAGS (def) & DF_REF_MW_HARDREG)
+	|| bitmap_bit_p (live, dregno)
+	|| 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);
+      df_set_note (REG_UNUSED, insn, reg);
+      dead_debug_insert_temp (debug, dregno, insn, DEBUG_TEMP_AFTER_WITH_REG);
+      if (REG_DEAD_DEBUGGING)
+	df_print_note ("adding 3: ", insn, REG_NOTES (insn));
+    }
+
+  return;
+}
+
+
+/* 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;
+  struct dead_debug_local debug;
+
+  dead_debug_local_init (&debug, NULL, NULL);
+
+  bitmap_copy (live, df_get_live_out (bb));
+  bitmap_clear (artificial_uses);
+
+  if (REG_DEAD_DEBUGGING && dump_file)
+    {
+      fprintf (dump_file, "live at bottom ");
+      df_print_regset (dump_file, live);
+    }
+
+  /* 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;
+
+      if (REG_DEAD_DEBUGGING && dump_file)
+	fprintf (dump_file, "artificial def %d\n", DF_REF_REGNO (def));
+
+      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);
+	}
+    }
+
+  if (REG_DEAD_DEBUGGING && dump_file)
+    {
+      fprintf (dump_file, "live before artificials out ");
+      df_print_regset (dump_file, live);
+    }
+
+  FOR_BB_INSNS_REVERSE (bb, insn)
+    {
+      unsigned int uid = INSN_UID (insn);
+      struct df_mw_hardreg **mws_rec;
+      int debug_insn;
+
+      if (!INSN_P (insn))
+	continue;
+
+      debug_insn = DEBUG_INSN_P (insn);
+
+      bitmap_clear (do_not_gen);
+      df_remove_dead_and_unused_notes (insn);
+
+      /* Process the defs.  */
+      if (CALL_P (insn))
+	{
+	  if (REG_DEAD_DEBUGGING && dump_file)
+	    {
+	      fprintf (dump_file, "processing call %d\n  live =", INSN_UID (insn));
+	      df_print_regset (dump_file, live);
+	    }
+
+	  /* 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))
+	      df_set_unused_notes_for_mw (insn,
+					  mws, live, do_not_gen,
+					  artificial_uses, &debug);
+	      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))
+		{
+		  df_create_unused_note (insn,
+					 def, live, artificial_uses, &debug);
+		  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))
+		df_set_unused_notes_for_mw (insn,
+					    mws, live, do_not_gen,
+					    artificial_uses, &debug);
+	      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);
+	      df_create_unused_note (insn,
+				     def, live, artificial_uses, &debug);
+
+	      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_USE_P (mws)
+	      && !df_ignore_stack_reg (mws->start_regno))
+	    {
+	      bool really_add_notes = debug_insn != 0;
+
+	      df_set_dead_notes_for_mw (insn,
+					mws, live, do_not_gen,
+					artificial_uses,
+					&really_add_notes);
+
+	      if (really_add_notes)
+		debug_insn = -1;
+	    }
+	  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);
+
+	  if (REG_DEAD_DEBUGGING && dump_file && !debug_insn)
+	    {
+	      fprintf (dump_file, "  regular looking at use ");
+	      df_ref_debug (use, dump_file);
+	    }
+
+	  if (!bitmap_bit_p (live, uregno))
+	    {
+	      if (debug_insn)
+		{
+		  if (debug_insn > 0)
+		    {
+		      /* We won't add REG_UNUSED or REG_DEAD notes for
+			 these, so we don't have to mess with them in
+			 debug insns either.  */
+		      if (!bitmap_bit_p (artificial_uses, uregno)
+			  && !df_ignore_stack_reg (uregno))
+			dead_debug_add (&debug, use, uregno);
+		      continue;
+		    }
+		  break;
+		}
+	      else
+		dead_debug_insert_temp (&debug, uregno, insn,
+					DEBUG_TEMP_BEFORE_WITH_REG);
+
+	      if ( (!(DF_REF_FLAGS (use)
+		      & (DF_REF_MW_HARDREG | DF_REF_READ_WRITE)))
+		   && (!bitmap_bit_p (do_not_gen, uregno))
+		   && (!bitmap_bit_p (artificial_uses, uregno))
+		   && (!df_ignore_stack_reg (uregno)))
+		{
+		  rtx reg = (DF_REF_LOC (use))
+                            ? *DF_REF_REAL_LOC (use) : DF_REF_REG (use);
+		  df_set_note (REG_DEAD, insn, reg);
+
+		  if (REG_DEAD_DEBUGGING)
+		    df_print_note ("adding 4: ", insn, REG_NOTES (insn));
+		}
+	      /* This register is now live.  */
+	      bitmap_set_bit (live, uregno);
+	    }
+	}
+
+      df_remove_dead_eq_notes (insn, live);
+
+      if (debug_insn == -1)
+	{
+	  /* ??? We could probably do better here, replacing dead
+	     registers with their definitions.  */
+	  INSN_VAR_LOCATION_LOC (insn) = gen_rtx_UNKNOWN_VAR_LOC ();
+	  df_insn_rescan_debug_internal (insn);
+	}
+    }
+
+  dead_debug_local_finish (&debug, NULL);
+}
+
+
+/* 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_head live, do_not_gen, artificial_uses;
+
+  bitmap_initialize (&live, &df_bitmap_obstack);
+  bitmap_initialize (&do_not_gen, &df_bitmap_obstack);
+  bitmap_initialize (&artificial_uses, &df_bitmap_obstack);
+
+  EXECUTE_IF_SET_IN_BITMAP (all_blocks, 0, bb_index, bi)
+  {
+    /* ??? Unlike fast DCE, we don't use global_debug for uses of dead
+       pseudos in debug insns because we don't always (re)visit blocks
+       with death points after visiting dead uses.  Even changing this
+       loop to postorder would still leave room for visiting a death
+       point before visiting a subsequent debug use.  */
+    df_note_bb_compute (bb_index, &live, &do_not_gen, &artificial_uses);
+  }
+
+  bitmap_clear (&live);
+  bitmap_clear (&do_not_gen);
+  bitmap_clear (&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,                       /* Debugging start insn.  */
+  NULL,                       /* Debugging end insn.  */
+  NULL,                       /* Incremental solution verify start.  */
+  NULL,                       /* Incremental solution verify end.  */
+  &problem_LR,                /* Dependent problem.  */
+  sizeof (struct df_scan_bb_info),/* Size of entry of block_info array.  */
+  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.  If you go backwards, defs are examined first to clear bits,
+   then uses are examined to set bits.  If you go forwards, defs are
+   examined first to set bits, then REG_DEAD and REG_UNUSED notes
+   are examined to clear bits.  In either case, the result of examining
+   a def can be undone (respectively by a use or a REG_UNUSED note).
+
+   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;
+      bitmap_set_bit (defs, DF_REF_REGNO (def));
+    }
+}
+
+/* Find the set of uses for INSN.  This includes partial defs.  */
+
+static void
+df_simulate_find_uses (rtx insn, bitmap uses)
+{
+  df_ref *rec;
+  unsigned int uid = INSN_UID (insn);
+
+  for (rec = DF_INSN_UID_DEFS (uid); *rec; rec++)
+    {
+      df_ref def = *rec;
+      if (DF_REF_FLAGS (def) & (DF_REF_PARTIAL | DF_REF_CONDITIONAL))
+	bitmap_set_bit (uses, DF_REF_REGNO (def));
+    }
+  for (rec = DF_INSN_UID_USES (uid); *rec; rec++)
+    {
+      df_ref use = *rec;
+      bitmap_set_bit (uses, DF_REF_REGNO (use));
+    }
+}
+
+/* Find the set of real DEFs, which are not clobbers, for INSN.  */
+
+void
+df_simulate_find_noclobber_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 (!(DF_REF_FLAGS (def) & (DF_REF_MUST_CLOBBER | DF_REF_MAY_CLOBBER)))
+	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);
+
+  if (DEBUG_INSN_P (insn))
+    return;
+
+  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 one.  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 (!NONDEBUG_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 first one.
+   ----------------------------------------------------------------------------*/
+
+/* Initialize the LIVE bitmap, which should be copied from DF_LIVE_IN or
+   DF_LR_IN for basic block BB, for forward scanning by marking artificial
+   defs live.  */
+
+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_set_bit (live, DF_REF_REGNO (def));
+    }
+}
+
+/* Simulate the forwards 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 DF_NOTE really is an active df problem.  */
+  gcc_assert (df_note);
+
+  /* Note that this is the opposite as how the problem is defined, because
+     in the LR problem defs _kill_ liveness.  However, they do so backwards,
+     while here the scan is performed forwards!  So, first assume that the
+     def is live, and if this is not true REG_UNUSED notes will rectify the
+     situation.  */
+  df_simulate_find_noclobber_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 (HARD_REGISTER_NUM_P (regno))
+	      bitmap_clear_range (live, regno,
+				  hard_regno_nregs[regno][GET_MODE (reg)]);
+	    else
+	      bitmap_clear_bit (live, regno);
+	  }
+	  break;
+	default:
+	  break;
+	}
+    }
+  df_simulate_fixup_sets (bb, live);
+}
+
+/* Used by the next two functions to encode information about the
+   memory references we found.  */
+#define MEMREF_NORMAL 1
+#define MEMREF_VOLATILE 2
+
+/* A subroutine of can_move_insns_across_p called through for_each_rtx.
+   Return either MEMREF_NORMAL or MEMREF_VOLATILE if a memory is found.  */
+
+static int
+find_memory (rtx *px, void *data ATTRIBUTE_UNUSED)
+{
+  rtx x = *px;
+
+  if (GET_CODE (x) == ASM_OPERANDS && MEM_VOLATILE_P (x))
+    return MEMREF_VOLATILE;
+
+  if (!MEM_P (x))
+    return 0;
+  if (MEM_VOLATILE_P (x))
+    return MEMREF_VOLATILE;
+  if (MEM_READONLY_P (x))
+    return 0;
+
+  return MEMREF_NORMAL;
+}
+
+/* A subroutine of can_move_insns_across_p called through note_stores.
+   DATA points to an integer in which we set either the bit for
+   MEMREF_NORMAL or the bit for MEMREF_VOLATILE if we find a MEM
+   of either kind.  */
+
+static void
+find_memory_stores (rtx x, const_rtx pat ATTRIBUTE_UNUSED,
+		    void *data ATTRIBUTE_UNUSED)
+{
+  int *pflags = (int *)data;
+  if (GET_CODE (x) == SUBREG)
+    x = XEXP (x, 0);
+  /* Treat stores to SP as stores to memory, this will prevent problems
+     when there are references to the stack frame.  */
+  if (x == stack_pointer_rtx)
+    *pflags |= MEMREF_VOLATILE;
+  if (!MEM_P (x))
+    return;
+  *pflags |= MEM_VOLATILE_P (x) ? MEMREF_VOLATILE : MEMREF_NORMAL;
+}
+
+/* Scan BB backwards, using df_simulate functions to keep track of
+   lifetimes, up to insn POINT.  The result is stored in LIVE.  */
+
+void
+simulate_backwards_to_point (basic_block bb, regset live, rtx point)
+{
+  rtx insn;
+  bitmap_copy (live, df_get_live_out (bb));
+  df_simulate_initialize_backwards (bb, live);
+
+  /* Scan and update life information until we reach the point we're
+     interested in.  */
+  for (insn = BB_END (bb); insn != point; insn = PREV_INSN (insn))
+    df_simulate_one_insn_backwards (bb, insn, live);
+}
+
+/* Return true if it is safe to move a group of insns, described by
+   the range FROM to TO, backwards across another group of insns,
+   described by ACROSS_FROM to ACROSS_TO.  It is assumed that there
+   are no insns between ACROSS_TO and FROM, but they may be in
+   different basic blocks; MERGE_BB is the block from which the
+   insns will be moved.  The caller must pass in a regset MERGE_LIVE
+   which specifies the registers live after TO.
+
+   This function may be called in one of two cases: either we try to
+   move identical instructions from all successor blocks into their
+   predecessor, or we try to move from only one successor block.  If
+   OTHER_BRANCH_LIVE is nonnull, it indicates that we're dealing with
+   the second case.  It should contain a set of registers live at the
+   end of ACROSS_TO which must not be clobbered by moving the insns.
+   In that case, we're also more careful about moving memory references
+   and trapping insns.
+
+   We return false if it is not safe to move the entire group, but it
+   may still be possible to move a subgroup.  PMOVE_UPTO, if nonnull,
+   is set to point at the last moveable insn in such a case.  */
+
+bool
+can_move_insns_across (rtx from, rtx to, rtx across_from, rtx across_to,
+		       basic_block merge_bb, regset merge_live,
+		       regset other_branch_live, rtx *pmove_upto)
+{
+  rtx insn, next, max_to;
+  bitmap merge_set, merge_use, local_merge_live;
+  bitmap test_set, test_use;
+  unsigned i, fail = 0;
+  bitmap_iterator bi;
+  int memrefs_in_across = 0;
+  int mem_sets_in_across = 0;
+  bool trapping_insns_in_across = false;
+
+  if (pmove_upto != NULL)
+    *pmove_upto = NULL_RTX;
+
+  /* Find real bounds, ignoring debug insns.  */
+  while (!NONDEBUG_INSN_P (from) && from != to)
+    from = NEXT_INSN (from);
+  while (!NONDEBUG_INSN_P (to) && from != to)
+    to = PREV_INSN (to);
+
+  for (insn = across_to; ; insn = next)
+    {
+      if (CALL_P (insn))
+	{
+	  if (RTL_CONST_OR_PURE_CALL_P (insn))
+	    /* Pure functions can read from memory.  Const functions can
+	       read from arguments that the ABI has forced onto the stack.
+	       Neither sort of read can be volatile.  */
+	    memrefs_in_across |= MEMREF_NORMAL;
+	  else
+	    {
+	      memrefs_in_across |= MEMREF_VOLATILE;
+	      mem_sets_in_across |= MEMREF_VOLATILE;
+	    }
+	}
+      if (NONDEBUG_INSN_P (insn))
+	{
+	  if (volatile_insn_p (PATTERN (insn)))
+	    return false;
+	  memrefs_in_across |= for_each_rtx (&PATTERN (insn), find_memory,
+					     NULL);
+	  note_stores (PATTERN (insn), find_memory_stores,
+		       &mem_sets_in_across);
+	  /* This is used just to find sets of the stack pointer.  */
+	  memrefs_in_across |= mem_sets_in_across;
+	  trapping_insns_in_across |= may_trap_p (PATTERN (insn));
+	}
+      next = PREV_INSN (insn);
+      if (insn == across_from)
+	break;
+    }
+
+  /* Collect:
+     MERGE_SET = set of registers set in MERGE_BB
+     MERGE_USE = set of registers used in MERGE_BB and live at its top
+     MERGE_LIVE = set of registers live at the point inside the MERGE
+     range that we've reached during scanning
+     TEST_SET = set of registers set between ACROSS_FROM and ACROSS_END.
+     TEST_USE = set of registers used between ACROSS_FROM and ACROSS_END,
+     and live before ACROSS_FROM.  */
+
+  merge_set = BITMAP_ALLOC (&reg_obstack);
+  merge_use = BITMAP_ALLOC (&reg_obstack);
+  local_merge_live = BITMAP_ALLOC (&reg_obstack);
+  test_set = BITMAP_ALLOC (&reg_obstack);
+  test_use = BITMAP_ALLOC (&reg_obstack);
+
+  /* Compute the set of registers set and used in the ACROSS range.  */
+  if (other_branch_live != NULL)
+    bitmap_copy (test_use, other_branch_live);
+  df_simulate_initialize_backwards (merge_bb, test_use);
+  for (insn = across_to; ; insn = next)
+    {
+      if (NONDEBUG_INSN_P (insn))
+	{
+	  df_simulate_find_defs (insn, test_set);
+	  df_simulate_defs (insn, test_use);
+	  df_simulate_uses (insn, test_use);
+	}
+      next = PREV_INSN (insn);
+      if (insn == across_from)
+	break;
+    }
+
+  /* Compute an upper bound for the amount of insns moved, by finding
+     the first insn in MERGE that sets a register in TEST_USE, or uses
+     a register in TEST_SET.  We also check for calls, trapping operations,
+     and memory references.  */
+  max_to = NULL_RTX;
+  for (insn = from; ; insn = next)
+    {
+      if (CALL_P (insn))
+	break;
+      if (NOTE_P (insn) && NOTE_KIND (insn) == NOTE_INSN_EPILOGUE_BEG)
+	break;
+      if (NONDEBUG_INSN_P (insn))
+	{
+	  if (may_trap_or_fault_p (PATTERN (insn))
+	      && (trapping_insns_in_across
+		  || other_branch_live != NULL
+		  || volatile_insn_p (PATTERN (insn))))
+	    break;
+
+	  /* We cannot move memory stores past each other, or move memory
+	     reads past stores, at least not without tracking them and
+	     calling true_dependence on every pair.
+
+	     If there is no other branch and no memory references or
+	     sets in the ACROSS range, we can move memory references
+	     freely, even volatile ones.
+
+	     Otherwise, the rules are as follows: volatile memory
+	     references and stores can't be moved at all, and any type
+	     of memory reference can't be moved if there are volatile
+	     accesses or stores in the ACROSS range.  That leaves
+	     normal reads, which can be moved, as the trapping case is
+	     dealt with elsewhere.  */
+	  if (other_branch_live != NULL || memrefs_in_across != 0)
+	    {
+	      int mem_ref_flags = 0;
+	      int mem_set_flags = 0;
+	      note_stores (PATTERN (insn), find_memory_stores, &mem_set_flags);
+	      mem_ref_flags = for_each_rtx (&PATTERN (insn), find_memory,
+					    NULL);
+	      /* Catch sets of the stack pointer.  */
+	      mem_ref_flags |= mem_set_flags;
+
+	      if ((mem_ref_flags | mem_set_flags) & MEMREF_VOLATILE)
+		break;
+	      if ((memrefs_in_across & MEMREF_VOLATILE) && mem_ref_flags != 0)
+		break;
+	      if (mem_set_flags != 0
+		  || (mem_sets_in_across != 0 && mem_ref_flags != 0))
+		break;
+	    }
+	  df_simulate_find_uses (insn, merge_use);
+	  /* We're only interested in uses which use a value live at
+	     the top, not one previously set in this block.  */
+	  bitmap_and_compl_into (merge_use, merge_set);
+	  df_simulate_find_defs (insn, merge_set);
+	  if (bitmap_intersect_p (merge_set, test_use)
+	      || bitmap_intersect_p (merge_use, test_set))
+	    break;
+#ifdef HAVE_cc0
+	  if (!sets_cc0_p (insn))
+#endif
+	    max_to = insn;
+	}
+      next = NEXT_INSN (insn);
+      if (insn == to)
+	break;
+    }
+  if (max_to != to)
+    fail = 1;
+
+  if (max_to == NULL_RTX || (fail && pmove_upto == NULL))
+    goto out;
+
+  /* Now, lower this upper bound by also taking into account that
+     a range of insns moved across ACROSS must not leave a register
+     live at the end that will be clobbered in ACROSS.  We need to
+     find a point where TEST_SET & LIVE == 0.
+
+     Insns in the MERGE range that set registers which are also set
+     in the ACROSS range may still be moved as long as we also move
+     later insns which use the results of the set, and make the
+     register dead again.  This is verified by the condition stated
+     above.  We only need to test it for registers that are set in
+     the moved region.
+
+     MERGE_LIVE is provided by the caller and holds live registers after
+     TO.  */
+  bitmap_copy (local_merge_live, merge_live);
+  for (insn = to; insn != max_to; insn = PREV_INSN (insn))
+    df_simulate_one_insn_backwards (merge_bb, insn, local_merge_live);
+
+  /* We're not interested in registers that aren't set in the moved
+     region at all.  */
+  bitmap_and_into (local_merge_live, merge_set);
+  for (;;)
+    {
+      if (NONDEBUG_INSN_P (insn))
+	{
+	  if (!bitmap_intersect_p (test_set, local_merge_live)
+#ifdef HAVE_cc0
+	      && !sets_cc0_p (insn)
+#endif
+	      )
+	    {
+	      max_to = insn;
+	      break;
+	    }
+
+	  df_simulate_one_insn_backwards (merge_bb, insn,
+					  local_merge_live);
+	}
+      if (insn == from)
+	{
+	  fail = 1;
+	  goto out;
+	}
+      insn = PREV_INSN (insn);
+    }
+
+  if (max_to != to)
+    fail = 1;
+
+  if (pmove_upto)
+    *pmove_upto = max_to;
+
+  /* For small register class machines, don't lengthen lifetimes of
+     hard registers before reload.  */
+  if (! reload_completed
+      && targetm.small_register_classes_for_mode_p (VOIDmode))
+    {
+      EXECUTE_IF_SET_IN_BITMAP (merge_set, 0, i, bi)
+	{
+	  if (i < FIRST_PSEUDO_REGISTER
+	      && ! fixed_regs[i]
+	      && ! global_regs[i])
+	    fail = 1;
+	}
+    }
+
+ out:
+  BITMAP_FREE (merge_set);
+  BITMAP_FREE (merge_use);
+  BITMAP_FREE (local_merge_live);
+  BITMAP_FREE (test_set);
+  BITMAP_FREE (test_use);
+
+  return !fail;
+}
+
+
+/*----------------------------------------------------------------------------
+   MULTIPLE DEFINITIONS
+
+   Find the locations in the function reached by multiple definition sites
+   for a live pseudo.  In and out bitvectors are built for each basic
+   block.  They are restricted for efficiency to live registers.
+
+   The gen and kill sets for the problem are obvious.  Together they
+   include all defined registers in a basic block; the gen set includes
+   registers where a partial or conditional or may-clobber definition is
+   last in the BB, while the kill set includes registers with a complete
+   definition coming last.  However, the computation of the dataflow
+   itself is interesting.
+
+   The idea behind it comes from SSA form's iterated dominance frontier
+   criterion for inserting PHI functions.  Just like in that case, we can use
+   the dominance frontier to find places where multiple definitions meet;
+   a register X defined in a basic block BB1 has multiple definitions in
+   basic blocks in BB1's dominance frontier.
+
+   So, the in-set of a basic block BB2 is not just the union of the
+   out-sets of BB2's predecessors, but includes some more bits that come
+   from the basic blocks of whose dominance frontier BB2 is part (BB1 in
+   the previous paragraph).  I called this set the init-set of BB2.
+
+      (Note: I actually use the kill-set only to build the init-set.
+      gen bits are anyway propagated from BB1 to BB2 by dataflow).
+
+    For example, if you have
+
+       BB1 : r10 = 0
+             r11 = 0
+             if <...> goto BB2 else goto BB3;
+
+       BB2 : r10 = 1
+             r12 = 1
+             goto BB3;
+
+       BB3 :
+
+    you have BB3 in BB2's dominance frontier but not in BB1's, so that the
+    init-set of BB3 includes r10 and r12, but not r11.  Note that we do
+    not need to iterate the dominance frontier, because we do not insert
+    anything like PHI functions there!  Instead, dataflow will take care of
+    propagating the information to BB3's successors.
+   ---------------------------------------------------------------------------*/
+
+/* Private data used to verify the solution for this problem.  */
+struct df_md_problem_data
+{
+  /* An obstack for the bitmaps we need for this problem.  */
+  bitmap_obstack md_bitmaps;
+};
+
+/* Scratch var used by transfer functions.  This is used to do md analysis
+   only for live registers.  */
+static bitmap_head df_md_scratch;
+
+
+static void
+df_md_free_bb_info (basic_block bb ATTRIBUTE_UNUSED,
+                    void *vbb_info)
+{
+  struct df_md_bb_info *bb_info = (struct df_md_bb_info *) vbb_info;
+  if (bb_info)
+    {
+      bitmap_clear (&bb_info->kill);
+      bitmap_clear (&bb_info->gen);
+      bitmap_clear (&bb_info->init);
+      bitmap_clear (&bb_info->in);
+      bitmap_clear (&bb_info->out);
+    }
+}
+
+
+/* Allocate or reset bitmaps for DF_MD. The solution bits are
+   not touched unless the block is new.  */
+
+static void
+df_md_alloc (bitmap all_blocks)
+{
+  unsigned int bb_index;
+  bitmap_iterator bi;
+  struct df_md_problem_data *problem_data;
+
+  df_grow_bb_info (df_md);
+  if (df_md->problem_data)
+    problem_data = (struct df_md_problem_data *) df_md->problem_data;
+  else
+    {
+      problem_data = XNEW (struct df_md_problem_data);
+      df_md->problem_data = problem_data;
+      bitmap_obstack_initialize (&problem_data->md_bitmaps);
+    }
+  bitmap_initialize (&df_md_scratch, &problem_data->md_bitmaps);
+
+  EXECUTE_IF_SET_IN_BITMAP (all_blocks, 0, bb_index, bi)
+    {
+      struct df_md_bb_info *bb_info = df_md_get_bb_info (bb_index);
+      /* When bitmaps are already initialized, just clear them.  */
+      if (bb_info->init.obstack)
+        {
+          bitmap_clear (&bb_info->init);
+          bitmap_clear (&bb_info->gen);
+          bitmap_clear (&bb_info->kill);
+          bitmap_clear (&bb_info->in);
+          bitmap_clear (&bb_info->out);
+        }
+      else
+        {
+	  bitmap_initialize (&bb_info->init, &problem_data->md_bitmaps);
+	  bitmap_initialize (&bb_info->gen, &problem_data->md_bitmaps);
+	  bitmap_initialize (&bb_info->kill, &problem_data->md_bitmaps);
+	  bitmap_initialize (&bb_info->in, &problem_data->md_bitmaps);
+	  bitmap_initialize (&bb_info->out, &problem_data->md_bitmaps);
+        }
+    }
+
+  df_md->optional_p = true;
+}
+
+/* Add the effect of the top artificial defs of BB to the multiple definitions
+   bitmap LOCAL_MD.  */
+
+void
+df_md_simulate_artificial_defs_at_top (basic_block bb, bitmap local_md)
+{
+  int bb_index = bb->index;
+  df_ref *def_rec;
+  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 | DF_REF_MAY_CLOBBER))
+	    bitmap_set_bit (local_md, dregno);
+	  else
+	    bitmap_clear_bit (local_md, dregno);
+	}
+    }
+}
+
+
+/* Add the effect of the defs of INSN to the reaching definitions bitmap
+   LOCAL_MD.  */
+
+void
+df_md_simulate_one_insn (basic_block bb ATTRIBUTE_UNUSED, rtx insn,
+                        bitmap local_md)
+{
+  unsigned uid = INSN_UID (insn);
+  df_ref *def_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);
+      if ((!(df->changeable_flags & DF_NO_HARD_REGS))
+          || (dregno >= FIRST_PSEUDO_REGISTER))
+        {
+          if (DF_REF_FLAGS (def)
+	      & (DF_REF_PARTIAL | DF_REF_CONDITIONAL | DF_REF_MAY_CLOBBER))
+           bitmap_set_bit (local_md, DF_REF_ID (def));
+         else
+           bitmap_clear_bit (local_md, DF_REF_ID (def));
+        }
+    }
+}
+
+static void
+df_md_bb_local_compute_process_def (struct df_md_bb_info *bb_info,
+                                    df_ref *def_rec,
+                                    int top_flag)
+{
+  df_ref def;
+  bitmap_clear (&seen_in_insn);
+
+  while ((def = *def_rec++) != NULL)
+    {
+      unsigned int dregno = DF_REF_REGNO (def);
+      if (((!(df->changeable_flags & DF_NO_HARD_REGS))
+	    || (dregno >= FIRST_PSEUDO_REGISTER))
+	  && top_flag == (DF_REF_FLAGS (def) & DF_REF_AT_TOP))
+	{
+          if (!bitmap_bit_p (&seen_in_insn, dregno))
+	    {
+	      if (DF_REF_FLAGS (def)
+	          & (DF_REF_PARTIAL | DF_REF_CONDITIONAL | DF_REF_MAY_CLOBBER))
+	        {
+	          bitmap_set_bit (&bb_info->gen, dregno);
+	          bitmap_clear_bit (&bb_info->kill, dregno);
+	        }
+	      else
+	        {
+		  /* When we find a clobber and a regular def,
+		     make sure the regular def wins.  */
+	          bitmap_set_bit (&seen_in_insn, dregno);
+	          bitmap_set_bit (&bb_info->kill, dregno);
+	          bitmap_clear_bit (&bb_info->gen, dregno);
+	        }
+	    }
+	}
+    }
+}
+
+
+/* Compute local multiple def info for basic block BB.  */
+
+static void
+df_md_bb_local_compute (unsigned int bb_index)
+{
+  basic_block bb = BASIC_BLOCK (bb_index);
+  struct df_md_bb_info *bb_info = df_md_get_bb_info (bb_index);
+  rtx insn;
+
+  /* Artificials are only hard regs.  */
+  if (!(df->changeable_flags & DF_NO_HARD_REGS))
+    df_md_bb_local_compute_process_def (bb_info,
+                                        df_get_artificial_defs (bb_index),
+                                        DF_REF_AT_TOP);
+
+  FOR_BB_INSNS (bb, insn)
+    {
+      unsigned int uid = INSN_UID (insn);
+      if (!INSN_P (insn))
+        continue;
+
+      df_md_bb_local_compute_process_def (bb_info, DF_INSN_UID_DEFS (uid), 0);
+    }
+
+  if (!(df->changeable_flags & DF_NO_HARD_REGS))
+    df_md_bb_local_compute_process_def (bb_info,
+                                        df_get_artificial_defs (bb_index),
+                                        0);
+}
+
+/* Compute local reaching def info for each basic block within BLOCKS.  */
+
+static void
+df_md_local_compute (bitmap all_blocks)
+{
+  unsigned int bb_index, df_bb_index;
+  bitmap_iterator bi1, bi2;
+  basic_block bb;
+  bitmap_head *frontiers;
+
+  bitmap_initialize (&seen_in_insn, &bitmap_default_obstack);
+
+  EXECUTE_IF_SET_IN_BITMAP (all_blocks, 0, bb_index, bi1)
+    {
+      df_md_bb_local_compute (bb_index);
+    }
+
+  bitmap_clear (&seen_in_insn);
+
+  frontiers = XNEWVEC (bitmap_head, last_basic_block);
+  FOR_ALL_BB (bb)
+    bitmap_initialize (&frontiers[bb->index], &bitmap_default_obstack);
+
+  compute_dominance_frontiers (frontiers);
+
+  /* Add each basic block's kills to the nodes in the frontier of the BB.  */
+  EXECUTE_IF_SET_IN_BITMAP (all_blocks, 0, bb_index, bi1)
+    {
+      bitmap kill = &df_md_get_bb_info (bb_index)->kill;
+      EXECUTE_IF_SET_IN_BITMAP (&frontiers[bb_index], 0, df_bb_index, bi2)
+	{
+	  basic_block bb = BASIC_BLOCK (df_bb_index);
+	  if (bitmap_bit_p (all_blocks, df_bb_index))
+	    bitmap_ior_and_into (&df_md_get_bb_info (df_bb_index)->init, kill,
+				 df_get_live_in (bb));
+	}
+    }
+
+  FOR_ALL_BB (bb)
+    bitmap_clear (&frontiers[bb->index]);
+  free (frontiers);
+}
+
+
+/* Reset the global solution for recalculation.  */
+
+static void
+df_md_reset (bitmap all_blocks)
+{
+  unsigned int bb_index;
+  bitmap_iterator bi;
+
+  EXECUTE_IF_SET_IN_BITMAP (all_blocks, 0, bb_index, bi)
+    {
+      struct df_md_bb_info *bb_info = df_md_get_bb_info (bb_index);
+      gcc_assert (bb_info);
+      bitmap_clear (&bb_info->in);
+      bitmap_clear (&bb_info->out);
+    }
+}
+
+static bool
+df_md_transfer_function (int bb_index)
+{
+  basic_block bb = BASIC_BLOCK (bb_index);
+  struct df_md_bb_info *bb_info = df_md_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 whether the sets changed in a
+     significant way; i.e. not just because the live set was anded in.  */
+  bitmap_and (&df_md_scratch, gen, df_get_live_out (bb));
+
+  /* Multiple definitions of a register are not relevant if it is not
+     live.  Thus we trim the result to the places where it is live.  */
+  bitmap_and_into (in, df_get_live_in (bb));
+
+  return bitmap_ior_and_compl (out, &df_md_scratch, in, kill);
+}
+
+/* Initialize the solution bit vectors for problem.  */
+
+static void
+df_md_init (bitmap all_blocks)
+{
+  unsigned int bb_index;
+  bitmap_iterator bi;
+
+  EXECUTE_IF_SET_IN_BITMAP (all_blocks, 0, bb_index, bi)
+    {
+      struct df_md_bb_info *bb_info = df_md_get_bb_info (bb_index);
+
+      bitmap_copy (&bb_info->in, &bb_info->init);
+      df_md_transfer_function (bb_index);
+    }
+}
+
+static void
+df_md_confluence_0 (basic_block bb)
+{
+  struct df_md_bb_info *bb_info = df_md_get_bb_info (bb->index);
+  bitmap_copy (&bb_info->in, &bb_info->init);
+}
+
+/* In of target gets or of out of source.  */
+
+static bool
+df_md_confluence_n (edge e)
+{
+  bitmap op1 = &df_md_get_bb_info (e->dest->index)->in;
+  bitmap op2 = &df_md_get_bb_info (e->src->index)->out;
+
+  if (e->flags & EDGE_FAKE)
+    return false;
+
+  if (e->flags & EDGE_EH)
+    return bitmap_ior_and_compl_into (op1, op2,
+				      regs_invalidated_by_call_regset);
+  else
+    return bitmap_ior_into (op1, op2);
+}
+
+/* Free all storage associated with the problem.  */
+
+static void
+df_md_free (void)
+{
+  struct df_md_problem_data *problem_data
+    = (struct df_md_problem_data *) df_md->problem_data;
+
+  bitmap_obstack_release (&problem_data->md_bitmaps);
+  free (problem_data);
+  df_md->problem_data = NULL;
+
+  df_md->block_info_size = 0;
+  free (df_md->block_info);
+  df_md->block_info = NULL;
+  free (df_md);
+}
+
+
+/* Debugging info at top of bb.  */
+
+static void
+df_md_top_dump (basic_block bb, FILE *file)
+{
+  struct df_md_bb_info *bb_info = df_md_get_bb_info (bb->index);
+  if (!bb_info)
+    return;
+
+  fprintf (file, ";; md  in  \t");
+  df_print_regset (file, &bb_info->in);
+  fprintf (file, ";; md  init  \t");
+  df_print_regset (file, &bb_info->init);
+  fprintf (file, ";; md  gen \t");
+  df_print_regset (file, &bb_info->gen);
+  fprintf (file, ";; md  kill \t");
+  df_print_regset (file, &bb_info->kill);
+}
+
+/* Debugging info at bottom of bb.  */
+
+static void
+df_md_bottom_dump (basic_block bb, FILE *file)
+{
+  struct df_md_bb_info *bb_info = df_md_get_bb_info (bb->index);
+  if (!bb_info)
+    return;
+
+  fprintf (file, ";; md  out \t");
+  df_print_regset (file, &bb_info->out);
+}
+
+static struct df_problem problem_MD =
+{
+  DF_MD,                      /* Problem id.  */
+  DF_FORWARD,                 /* Direction.  */
+  df_md_alloc,                /* Allocate the problem specific data.  */
+  df_md_reset,                /* Reset global information.  */
+  df_md_free_bb_info,         /* Free basic block info.  */
+  df_md_local_compute,        /* Local compute function.  */
+  df_md_init,                 /* Init the solution specific data.  */
+  df_worklist_dataflow,       /* Worklist solver.  */
+  df_md_confluence_0,         /* Confluence operator 0.  */
+  df_md_confluence_n,         /* Confluence operator n.  */
+  df_md_transfer_function,    /* Transfer function.  */
+  NULL,                       /* Finalize function.  */
+  df_md_free,                 /* Free all of the problem information.  */
+  df_md_free,                 /* Remove this problem from the stack of dataflow problems.  */
+  NULL,                       /* Debugging.  */
+  df_md_top_dump,             /* Debugging start block.  */
+  df_md_bottom_dump,          /* Debugging end block.  */
+  NULL,                       /* Debugging start insn.  */
+  NULL,                       /* Debugging end insn.  */
+  NULL,			      /* Incremental solution verify start.  */
+  NULL,			      /* Incremental solution verify end.  */
+  NULL,                       /* Dependent problem.  */
+  sizeof (struct df_md_bb_info),/* Size of entry of block_info array.  */
+  TV_DF_MD,                   /* Timing variable.  */
+  false                       /* Reset blocks on dropping out of blocks_to_analyze.  */
+};
+
+/* Create a new MD instance and add it to the existing instance
+   of DF.  */
+
+void
+df_md_add_problem (void)
+{
+  df_add_problem (&problem_MD);
+}
+
+
+