Initial checkin of GCC 4.9.0 from trunk (r208799).

Change-Id: I48a3c08bb98542aa215912a75f03c0890e497dba

1 files changed, 10391 insertions, 0 deletions

diff --git a/gcc-4.9/gcc/var-tracking.c b/gcc-4.9/gcc/var-tracking.c
new file mode 100644
index 000000000..65d82854c
--- /dev/null
+++ b/gcc-4.9/gcc/var-tracking.c
@@ -0,0 +1,10391 @@
+/* Variable tracking routines for the GNU compiler.
+   Copyright (C) 2002-2014 Free Software Foundation, Inc.
+
+   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/>.  */
+
+/* This file contains the variable tracking pass.  It computes where
+   variables are located (which registers or where in memory) at each position
+   in instruction stream and emits notes describing the locations.
+   Debug information (DWARF2 location lists) is finally generated from
+   these notes.
+   With this debug information, it is possible to show variables
+   even when debugging optimized code.
+
+   How does the variable tracking pass work?
+
+   First, it scans RTL code for uses, stores and clobbers (register/memory
+   references in instructions), for call insns and for stack adjustments
+   separately for each basic block and saves them to an array of micro
+   operations.
+   The micro operations of one instruction are ordered so that
+   pre-modifying stack adjustment < use < use with no var < call insn <
+     < clobber < set < post-modifying stack adjustment
+
+   Then, a forward dataflow analysis is performed to find out how locations
+   of variables change through code and to propagate the variable locations
+   along control flow graph.
+   The IN set for basic block BB is computed as a union of OUT sets of BB's
+   predecessors, the OUT set for BB is copied from the IN set for BB and
+   is changed according to micro operations in BB.
+
+   The IN and OUT sets for basic blocks consist of a current stack adjustment
+   (used for adjusting offset of variables addressed using stack pointer),
+   the table of structures describing the locations of parts of a variable
+   and for each physical register a linked list for each physical register.
+   The linked list is a list of variable parts stored in the register,
+   i.e. it is a list of triplets (reg, decl, offset) where decl is
+   REG_EXPR (reg) and offset is REG_OFFSET (reg).  The linked list is used for
+   effective deleting appropriate variable parts when we set or clobber the
+   register.
+
+   There may be more than one variable part in a register.  The linked lists
+   should be pretty short so it is a good data structure here.
+   For example in the following code, register allocator may assign same
+   register to variables A and B, and both of them are stored in the same
+   register in CODE:
+
+     if (cond)
+       set A;
+     else
+       set B;
+     CODE;
+     if (cond)
+       use A;
+     else
+       use B;
+
+   Finally, the NOTE_INSN_VAR_LOCATION notes describing the variable locations
+   are emitted to appropriate positions in RTL code.  Each such a note describes
+   the location of one variable at the point in instruction stream where the
+   note is.  There is no need to emit a note for each variable before each
+   instruction, we only emit these notes where the location of variable changes
+   (this means that we also emit notes for changes between the OUT set of the
+   previous block and the IN set of the current block).
+
+   The notes consist of two parts:
+   1. the declaration (from REG_EXPR or MEM_EXPR)
+   2. the location of a variable - it is either a simple register/memory
+      reference (for simple variables, for example int),
+      or a parallel of register/memory references (for a large variables
+      which consist of several parts, for example long long).
+
+*/
+
+#include "config.h"
+#include "system.h"
+#include "coretypes.h"
+#include "tm.h"
+#include "rtl.h"
+#include "tree.h"
+#include "varasm.h"
+#include "stor-layout.h"
+#include "pointer-set.h"
+#include "hash-table.h"
+#include "basic-block.h"
+#include "tm_p.h"
+#include "hard-reg-set.h"
+#include "flags.h"
+#include "insn-config.h"
+#include "reload.h"
+#include "sbitmap.h"
+#include "alloc-pool.h"
+#include "fibheap.h"
+#include "regs.h"
+#include "expr.h"
+#include "tree-pass.h"
+#include "bitmap.h"
+#include "tree-dfa.h"
+#include "tree-ssa.h"
+#include "cselib.h"
+#include "target.h"
+#include "params.h"
+#include "diagnostic.h"
+#include "tree-pretty-print.h"
+#include "recog.h"
+#include "tm_p.h"
+#include "alias.h"
+
+/* var-tracking.c assumes that tree code with the same value as VALUE rtx code
+   has no chance to appear in REG_EXPR/MEM_EXPRs and isn't a decl.
+   Currently the value is the same as IDENTIFIER_NODE, which has such
+   a property.  If this compile time assertion ever fails, make sure that
+   the new tree code that equals (int) VALUE has the same property.  */
+extern char check_value_val[(int) VALUE == (int) IDENTIFIER_NODE ? 1 : -1];
+
+/* Type of micro operation.  */
+enum micro_operation_type
+{
+  MO_USE,	/* Use location (REG or MEM).  */
+  MO_USE_NO_VAR,/* Use location which is not associated with a variable
+		   or the variable is not trackable.  */
+  MO_VAL_USE,	/* Use location which is associated with a value.  */
+  MO_VAL_LOC,   /* Use location which appears in a debug insn.  */
+  MO_VAL_SET,	/* Set location associated with a value.  */
+  MO_SET,	/* Set location.  */
+  MO_COPY,	/* Copy the same portion of a variable from one
+		   location to another.  */
+  MO_CLOBBER,	/* Clobber location.  */
+  MO_CALL,	/* Call insn.  */
+  MO_ADJUST	/* Adjust stack pointer.  */
+
+};
+
+static const char * const ATTRIBUTE_UNUSED
+micro_operation_type_name[] = {
+  "MO_USE",
+  "MO_USE_NO_VAR",
+  "MO_VAL_USE",
+  "MO_VAL_LOC",
+  "MO_VAL_SET",
+  "MO_SET",
+  "MO_COPY",
+  "MO_CLOBBER",
+  "MO_CALL",
+  "MO_ADJUST"
+};
+
+/* Where shall the note be emitted?  BEFORE or AFTER the instruction.
+   Notes emitted as AFTER_CALL are to take effect during the call,
+   rather than after the call.  */
+enum emit_note_where
+{
+  EMIT_NOTE_BEFORE_INSN,
+  EMIT_NOTE_AFTER_INSN,
+  EMIT_NOTE_AFTER_CALL_INSN
+};
+
+/* Structure holding information about micro operation.  */
+typedef struct micro_operation_def
+{
+  /* Type of micro operation.  */
+  enum micro_operation_type type;
+
+  /* The instruction which the micro operation is in, for MO_USE,
+     MO_USE_NO_VAR, MO_CALL and MO_ADJUST, or the subsequent
+     instruction or note in the original flow (before any var-tracking
+     notes are inserted, to simplify emission of notes), for MO_SET
+     and MO_CLOBBER.  */
+  rtx insn;
+
+  union {
+    /* Location.  For MO_SET and MO_COPY, this is the SET that
+       performs the assignment, if known, otherwise it is the target
+       of the assignment.  For MO_VAL_USE and MO_VAL_SET, it is a
+       CONCAT of the VALUE and the LOC associated with it.  For
+       MO_VAL_LOC, it is a CONCAT of the VALUE and the VAR_LOCATION
+       associated with it.  */
+    rtx loc;
+
+    /* Stack adjustment.  */
+    HOST_WIDE_INT adjust;
+  } u;
+} micro_operation;
+
+
+/* A declaration of a variable, or an RTL value being handled like a
+   declaration.  */
+typedef void *decl_or_value;
+
+/* Return true if a decl_or_value DV is a DECL or NULL.  */
+static inline bool
+dv_is_decl_p (decl_or_value dv)
+{
+  return !dv || (int) TREE_CODE ((tree) dv) != (int) VALUE;
+}
+
+/* Return true if a decl_or_value is a VALUE rtl.  */
+static inline bool
+dv_is_value_p (decl_or_value dv)
+{
+  return dv && !dv_is_decl_p (dv);
+}
+
+/* Return the decl in the decl_or_value.  */
+static inline tree
+dv_as_decl (decl_or_value dv)
+{
+  gcc_checking_assert (dv_is_decl_p (dv));
+  return (tree) dv;
+}
+
+/* Return the value in the decl_or_value.  */
+static inline rtx
+dv_as_value (decl_or_value dv)
+{
+  gcc_checking_assert (dv_is_value_p (dv));
+  return (rtx)dv;
+}
+
+/* Return the opaque pointer in the decl_or_value.  */
+static inline void *
+dv_as_opaque (decl_or_value dv)
+{
+  return dv;
+}
+
+
+/* Description of location of a part of a variable.  The content of a physical
+   register is described by a chain of these structures.
+   The chains are pretty short (usually 1 or 2 elements) and thus
+   chain is the best data structure.  */
+typedef struct attrs_def
+{
+  /* Pointer to next member of the list.  */
+  struct attrs_def *next;
+
+  /* The rtx of register.  */
+  rtx loc;
+
+  /* The declaration corresponding to LOC.  */
+  decl_or_value dv;
+
+  /* Offset from start of DECL.  */
+  HOST_WIDE_INT offset;
+} *attrs;
+
+/* Structure for chaining the locations.  */
+typedef struct location_chain_def
+{
+  /* Next element in the chain.  */
+  struct location_chain_def *next;
+
+  /* The location (REG, MEM or VALUE).  */
+  rtx loc;
+
+  /* The "value" stored in this location.  */
+  rtx set_src;
+
+  /* Initialized? */
+  enum var_init_status init;
+} *location_chain;
+
+/* A vector of loc_exp_dep holds the active dependencies of a one-part
+   DV on VALUEs, i.e., the VALUEs expanded so as to form the current
+   location of DV.  Each entry is also part of VALUE' s linked-list of
+   backlinks back to DV.  */
+typedef struct loc_exp_dep_s
+{
+  /* The dependent DV.  */
+  decl_or_value dv;
+  /* The dependency VALUE or DECL_DEBUG.  */
+  rtx value;
+  /* The next entry in VALUE's backlinks list.  */
+  struct loc_exp_dep_s *next;
+  /* A pointer to the pointer to this entry (head or prev's next) in
+     the doubly-linked list.  */
+  struct loc_exp_dep_s **pprev;
+} loc_exp_dep;
+
+
+/* This data structure holds information about the depth of a variable
+   expansion.  */
+typedef struct expand_depth_struct
+{
+  /* This measures the complexity of the expanded expression.  It
+     grows by one for each level of expansion that adds more than one
+     operand.  */
+  int complexity;
+  /* This counts the number of ENTRY_VALUE expressions in an
+     expansion.  We want to minimize their use.  */
+  int entryvals;
+} expand_depth;
+
+/* This data structure is allocated for one-part variables at the time
+   of emitting notes.  */
+struct onepart_aux
+{
+  /* Doubly-linked list of dependent DVs.  These are DVs whose cur_loc
+     computation used the expansion of this variable, and that ought
+     to be notified should this variable change.  If the DV's cur_loc
+     expanded to NULL, all components of the loc list are regarded as
+     active, so that any changes in them give us a chance to get a
+     location.  Otherwise, only components of the loc that expanded to
+     non-NULL are regarded as active dependencies.  */
+  loc_exp_dep *backlinks;
+  /* This holds the LOC that was expanded into cur_loc.  We need only
+     mark a one-part variable as changed if the FROM loc is removed,
+     or if it has no known location and a loc is added, or if it gets
+     a change notification from any of its active dependencies.  */
+  rtx from;
+  /* The depth of the cur_loc expression.  */
+  expand_depth depth;
+  /* Dependencies actively used when expand FROM into cur_loc.  */
+  vec<loc_exp_dep, va_heap, vl_embed> deps;
+};
+
+/* Structure describing one part of variable.  */
+typedef struct variable_part_def
+{
+  /* Chain of locations of the part.  */
+  location_chain loc_chain;
+
+  /* Location which was last emitted to location list.  */
+  rtx cur_loc;
+
+  union variable_aux
+  {
+    /* The offset in the variable, if !var->onepart.  */
+    HOST_WIDE_INT offset;
+
+    /* Pointer to auxiliary data, if var->onepart and emit_notes.  */
+    struct onepart_aux *onepaux;
+  } aux;
+} variable_part;
+
+/* Maximum number of location parts.  */
+#define MAX_VAR_PARTS 16
+
+/* Enumeration type used to discriminate various types of one-part
+   variables.  */
+typedef enum onepart_enum
+{
+  /* Not a one-part variable.  */
+  NOT_ONEPART = 0,
+  /* A one-part DECL that is not a DEBUG_EXPR_DECL.  */
+  ONEPART_VDECL = 1,
+  /* A DEBUG_EXPR_DECL.  */
+  ONEPART_DEXPR = 2,
+  /* A VALUE.  */
+  ONEPART_VALUE = 3
+} onepart_enum_t;
+
+/* Structure describing where the variable is located.  */
+typedef struct variable_def
+{
+  /* The declaration of the variable, or an RTL value being handled
+     like a declaration.  */
+  decl_or_value dv;
+
+  /* Reference count.  */
+  int refcount;
+
+  /* Number of variable parts.  */
+  char n_var_parts;
+
+  /* What type of DV this is, according to enum onepart_enum.  */
+  ENUM_BITFIELD (onepart_enum) onepart : CHAR_BIT;
+
+  /* True if this variable_def struct is currently in the
+     changed_variables hash table.  */
+  bool in_changed_variables;
+
+  /* The variable parts.  */
+  variable_part var_part[1];
+} *variable;
+typedef const struct variable_def *const_variable;
+
+/* Pointer to the BB's information specific to variable tracking pass.  */
+#define VTI(BB) ((variable_tracking_info) (BB)->aux)
+
+/* Macro to access MEM_OFFSET as an HOST_WIDE_INT.  Evaluates MEM twice.  */
+#define INT_MEM_OFFSET(mem) (MEM_OFFSET_KNOWN_P (mem) ? MEM_OFFSET (mem) : 0)
+
+#if ENABLE_CHECKING && (GCC_VERSION >= 2007)
+
+/* Access VAR's Ith part's offset, checking that it's not a one-part
+   variable.  */
+#define VAR_PART_OFFSET(var, i) __extension__			\
+(*({  variable const __v = (var);				\
+      gcc_checking_assert (!__v->onepart);			\
+      &__v->var_part[(i)].aux.offset; }))
+
+/* Access VAR's one-part auxiliary data, checking that it is a
+   one-part variable.  */
+#define VAR_LOC_1PAUX(var) __extension__			\
+(*({  variable const __v = (var);				\
+      gcc_checking_assert (__v->onepart);			\
+      &__v->var_part[0].aux.onepaux; }))
+
+#else
+#define VAR_PART_OFFSET(var, i) ((var)->var_part[(i)].aux.offset)
+#define VAR_LOC_1PAUX(var) ((var)->var_part[0].aux.onepaux)
+#endif
+
+/* These are accessor macros for the one-part auxiliary data.  When
+   convenient for users, they're guarded by tests that the data was
+   allocated.  */
+#define VAR_LOC_DEP_LST(var) (VAR_LOC_1PAUX (var)		  \
+			      ? VAR_LOC_1PAUX (var)->backlinks	  \
+			      : NULL)
+#define VAR_LOC_DEP_LSTP(var) (VAR_LOC_1PAUX (var)		  \
+			       ? &VAR_LOC_1PAUX (var)->backlinks  \
+			       : NULL)
+#define VAR_LOC_FROM(var) (VAR_LOC_1PAUX (var)->from)
+#define VAR_LOC_DEPTH(var) (VAR_LOC_1PAUX (var)->depth)
+#define VAR_LOC_DEP_VEC(var) (VAR_LOC_1PAUX (var)		  \
+			      ? &VAR_LOC_1PAUX (var)->deps	  \
+			      : NULL)
+
+
+
+typedef unsigned int dvuid;
+
+/* Return the uid of DV.  */
+
+static inline dvuid
+dv_uid (decl_or_value dv)
+{
+  if (dv_is_value_p (dv))
+    return CSELIB_VAL_PTR (dv_as_value (dv))->uid;
+  else
+    return DECL_UID (dv_as_decl (dv));
+}
+
+/* Compute the hash from the uid.  */
+
+static inline hashval_t
+dv_uid2hash (dvuid uid)
+{
+  return uid;
+}
+
+/* The hash function for a mask table in a shared_htab chain.  */
+
+static inline hashval_t
+dv_htab_hash (decl_or_value dv)
+{
+  return dv_uid2hash (dv_uid (dv));
+}
+
+static void variable_htab_free (void *);
+
+/* Variable hashtable helpers.  */
+
+struct variable_hasher
+{
+  typedef variable_def value_type;
+  typedef void compare_type;
+  static inline hashval_t hash (const value_type *);
+  static inline bool equal (const value_type *, const compare_type *);
+  static inline void remove (value_type *);
+};
+
+/* The hash function for variable_htab, computes the hash value
+   from the declaration of variable X.  */
+
+inline hashval_t
+variable_hasher::hash (const value_type *v)
+{
+  return dv_htab_hash (v->dv);
+}
+
+/* Compare the declaration of variable X with declaration Y.  */
+
+inline bool
+variable_hasher::equal (const value_type *v, const compare_type *y)
+{
+  decl_or_value dv = CONST_CAST2 (decl_or_value, const void *, y);
+
+  return (dv_as_opaque (v->dv) == dv_as_opaque (dv));
+}
+
+/* Free the element of VARIABLE_HTAB (its type is struct variable_def).  */
+
+inline void
+variable_hasher::remove (value_type *var)
+{
+  variable_htab_free (var);
+}
+
+typedef hash_table <variable_hasher> variable_table_type;
+typedef variable_table_type::iterator variable_iterator_type;
+
+/* Structure for passing some other parameters to function
+   emit_note_insn_var_location.  */
+typedef struct emit_note_data_def
+{
+  /* The instruction which the note will be emitted before/after.  */
+  rtx insn;
+
+  /* Where the note will be emitted (before/after insn)?  */
+  enum emit_note_where where;
+
+  /* The variables and values active at this point.  */
+  variable_table_type vars;
+} emit_note_data;
+
+/* Structure holding a refcounted hash table.  If refcount > 1,
+   it must be first unshared before modified.  */
+typedef struct shared_hash_def
+{
+  /* Reference count.  */
+  int refcount;
+
+  /* Actual hash table.  */
+  variable_table_type htab;
+} *shared_hash;
+
+/* Structure holding the IN or OUT set for a basic block.  */
+typedef struct dataflow_set_def
+{
+  /* Adjustment of stack offset.  */
+  HOST_WIDE_INT stack_adjust;
+
+  /* Attributes for registers (lists of attrs).  */
+  attrs regs[FIRST_PSEUDO_REGISTER];
+
+  /* Variable locations.  */
+  shared_hash vars;
+
+  /* Vars that is being traversed.  */
+  shared_hash traversed_vars;
+} dataflow_set;
+
+/* The structure (one for each basic block) containing the information
+   needed for variable tracking.  */
+typedef struct variable_tracking_info_def
+{
+  /* The vector of micro operations.  */
+  vec<micro_operation> mos;
+
+  /* The IN and OUT set for dataflow analysis.  */
+  dataflow_set in;
+  dataflow_set out;
+
+  /* The permanent-in dataflow set for this block.  This is used to
+     hold values for which we had to compute entry values.  ??? This
+     should probably be dynamically allocated, to avoid using more
+     memory in non-debug builds.  */
+  dataflow_set *permp;
+
+  /* Has the block been visited in DFS?  */
+  bool visited;
+
+  /* Has the block been flooded in VTA?  */
+  bool flooded;
+
+} *variable_tracking_info;
+
+/* Alloc pool for struct attrs_def.  */
+static alloc_pool attrs_pool;
+
+/* Alloc pool for struct variable_def with MAX_VAR_PARTS entries.  */
+static alloc_pool var_pool;
+
+/* Alloc pool for struct variable_def with a single var_part entry.  */
+static alloc_pool valvar_pool;
+
+/* Alloc pool for struct location_chain_def.  */
+static alloc_pool loc_chain_pool;
+
+/* Alloc pool for struct shared_hash_def.  */
+static alloc_pool shared_hash_pool;
+
+/* Alloc pool for struct loc_exp_dep_s for NOT_ONEPART variables.  */
+static alloc_pool loc_exp_dep_pool;
+
+/* Changed variables, notes will be emitted for them.  */
+static variable_table_type changed_variables;
+
+/* Shall notes be emitted?  */
+static bool emit_notes;
+
+/* Values whose dynamic location lists have gone empty, but whose
+   cselib location lists are still usable.  Use this to hold the
+   current location, the backlinks, etc, during emit_notes.  */
+static variable_table_type dropped_values;
+
+/* Empty shared hashtable.  */
+static shared_hash empty_shared_hash;
+
+/* Scratch register bitmap used by cselib_expand_value_rtx.  */
+static bitmap scratch_regs = NULL;
+
+#ifdef HAVE_window_save
+typedef struct GTY(()) parm_reg {
+  rtx outgoing;
+  rtx incoming;
+} parm_reg_t;
+
+
+/* Vector of windowed parameter registers, if any.  */
+static vec<parm_reg_t, va_gc> *windowed_parm_regs = NULL;
+#endif
+
+/* Variable used to tell whether cselib_process_insn called our hook.  */
+static bool cselib_hook_called;
+
+/* Local function prototypes.  */
+static void stack_adjust_offset_pre_post (rtx, HOST_WIDE_INT *,
+					  HOST_WIDE_INT *);
+static void insn_stack_adjust_offset_pre_post (rtx, HOST_WIDE_INT *,
+					       HOST_WIDE_INT *);
+static bool vt_stack_adjustments (void);
+
+static void init_attrs_list_set (attrs *);
+static void attrs_list_clear (attrs *);
+static attrs attrs_list_member (attrs, decl_or_value, HOST_WIDE_INT);
+static void attrs_list_insert (attrs *, decl_or_value, HOST_WIDE_INT, rtx);
+static void attrs_list_copy (attrs *, attrs);
+static void attrs_list_union (attrs *, attrs);
+
+static variable_def **unshare_variable (dataflow_set *set, variable_def **slot,
+					variable var, enum var_init_status);
+static void vars_copy (variable_table_type, variable_table_type);
+static tree var_debug_decl (tree);
+static void var_reg_set (dataflow_set *, rtx, enum var_init_status, rtx);
+static void var_reg_delete_and_set (dataflow_set *, rtx, bool,
+				    enum var_init_status, rtx);
+static void var_reg_delete (dataflow_set *, rtx, bool);
+static void var_regno_delete (dataflow_set *, int);
+static void var_mem_set (dataflow_set *, rtx, enum var_init_status, rtx);
+static void var_mem_delete_and_set (dataflow_set *, rtx, bool,
+				    enum var_init_status, rtx);
+static void var_mem_delete (dataflow_set *, rtx, bool);
+
+static void dataflow_set_init (dataflow_set *);
+static void dataflow_set_clear (dataflow_set *);
+static void dataflow_set_copy (dataflow_set *, dataflow_set *);
+static int variable_union_info_cmp_pos (const void *, const void *);
+static void dataflow_set_union (dataflow_set *, dataflow_set *);
+static location_chain find_loc_in_1pdv (rtx, variable, variable_table_type);
+static bool canon_value_cmp (rtx, rtx);
+static int loc_cmp (rtx, rtx);
+static bool variable_part_different_p (variable_part *, variable_part *);
+static bool onepart_variable_different_p (variable, variable);
+static bool variable_different_p (variable, variable);
+static bool dataflow_set_different (dataflow_set *, dataflow_set *);
+static void dataflow_set_destroy (dataflow_set *);
+
+static bool contains_symbol_ref (rtx);
+static bool track_expr_p (tree, bool);
+static bool same_variable_part_p (rtx, tree, HOST_WIDE_INT);
+static int add_uses (rtx *, void *);
+static void add_uses_1 (rtx *, void *);
+static void add_stores (rtx, const_rtx, void *);
+static bool compute_bb_dataflow (basic_block);
+static bool vt_find_locations (void);
+
+static void dump_attrs_list (attrs);
+static void dump_var (variable);
+static void dump_vars (variable_table_type);
+static void dump_dataflow_set (dataflow_set *);
+static void dump_dataflow_sets (void);
+
+static void set_dv_changed (decl_or_value, bool);
+static void variable_was_changed (variable, dataflow_set *);
+static variable_def **set_slot_part (dataflow_set *, rtx, variable_def **,
+				     decl_or_value, HOST_WIDE_INT,
+				     enum var_init_status, rtx);
+static void set_variable_part (dataflow_set *, rtx,
+			       decl_or_value, HOST_WIDE_INT,
+			       enum var_init_status, rtx, enum insert_option);
+static variable_def **clobber_slot_part (dataflow_set *, rtx,
+					 variable_def **, HOST_WIDE_INT, rtx);
+static void clobber_variable_part (dataflow_set *, rtx,
+				   decl_or_value, HOST_WIDE_INT, rtx);
+static variable_def **delete_slot_part (dataflow_set *, rtx, variable_def **,
+					HOST_WIDE_INT);
+static void delete_variable_part (dataflow_set *, rtx,
+				  decl_or_value, HOST_WIDE_INT);
+static void emit_notes_in_bb (basic_block, dataflow_set *);
+static void vt_emit_notes (void);
+
+static bool vt_get_decl_and_offset (rtx, tree *, HOST_WIDE_INT *);
+static void vt_add_function_parameters (void);
+static bool vt_initialize (void);
+static void vt_finalize (void);
+
+/* Given a SET, calculate the amount of stack adjustment it contains
+   PRE- and POST-modifying stack pointer.
+   This function is similar to stack_adjust_offset.  */
+
+static void
+stack_adjust_offset_pre_post (rtx pattern, HOST_WIDE_INT *pre,
+			      HOST_WIDE_INT *post)
+{
+  rtx src = SET_SRC (pattern);
+  rtx dest = SET_DEST (pattern);
+  enum rtx_code code;
+
+  if (dest == stack_pointer_rtx)
+    {
+      /* (set (reg sp) (plus (reg sp) (const_int))) */
+      code = GET_CODE (src);
+      if (! (code == PLUS || code == MINUS)
+	  || XEXP (src, 0) != stack_pointer_rtx
+	  || !CONST_INT_P (XEXP (src, 1)))
+	return;
+
+      if (code == MINUS)
+	*post += INTVAL (XEXP (src, 1));
+      else
+	*post -= INTVAL (XEXP (src, 1));
+    }
+  else if (MEM_P (dest))
+    {
+      /* (set (mem (pre_dec (reg sp))) (foo)) */
+      src = XEXP (dest, 0);
+      code = GET_CODE (src);
+
+      switch (code)
+	{
+	case PRE_MODIFY:
+	case POST_MODIFY:
+	  if (XEXP (src, 0) == stack_pointer_rtx)
+	    {
+	      rtx val = XEXP (XEXP (src, 1), 1);
+	      /* We handle only adjustments by constant amount.  */
+	      gcc_assert (GET_CODE (XEXP (src, 1)) == PLUS &&
+			  CONST_INT_P (val));
+
+	      if (code == PRE_MODIFY)
+		*pre -= INTVAL (val);
+	      else
+		*post -= INTVAL (val);
+	      break;
+	    }
+	  return;
+
+	case PRE_DEC:
+	  if (XEXP (src, 0) == stack_pointer_rtx)
+	    {
+	      *pre += GET_MODE_SIZE (GET_MODE (dest));
+	      break;
+	    }
+	  return;
+
+	case POST_DEC:
+	  if (XEXP (src, 0) == stack_pointer_rtx)
+	    {
+	      *post += GET_MODE_SIZE (GET_MODE (dest));
+	      break;
+	    }
+	  return;
+
+	case PRE_INC:
+	  if (XEXP (src, 0) == stack_pointer_rtx)
+	    {
+	      *pre -= GET_MODE_SIZE (GET_MODE (dest));
+	      break;
+	    }
+	  return;
+
+	case POST_INC:
+	  if (XEXP (src, 0) == stack_pointer_rtx)
+	    {
+	      *post -= GET_MODE_SIZE (GET_MODE (dest));
+	      break;
+	    }
+	  return;
+
+	default:
+	  return;
+	}
+    }
+}
+
+/* Given an INSN, calculate the amount of stack adjustment it contains
+   PRE- and POST-modifying stack pointer.  */
+
+static void
+insn_stack_adjust_offset_pre_post (rtx insn, HOST_WIDE_INT *pre,
+				   HOST_WIDE_INT *post)
+{
+  rtx pattern;
+
+  *pre = 0;
+  *post = 0;
+
+  pattern = PATTERN (insn);
+  if (RTX_FRAME_RELATED_P (insn))
+    {
+      rtx expr = find_reg_note (insn, REG_FRAME_RELATED_EXPR, NULL_RTX);
+      if (expr)
+	pattern = XEXP (expr, 0);
+    }
+
+  if (GET_CODE (pattern) == SET)
+    stack_adjust_offset_pre_post (pattern, pre, post);
+  else if (GET_CODE (pattern) == PARALLEL
+	   || GET_CODE (pattern) == SEQUENCE)
+    {
+      int i;
+
+      /* There may be stack adjustments inside compound insns.  Search
+	 for them.  */
+      for ( i = XVECLEN (pattern, 0) - 1; i >= 0; i--)
+	if (GET_CODE (XVECEXP (pattern, 0, i)) == SET)
+	  stack_adjust_offset_pre_post (XVECEXP (pattern, 0, i), pre, post);
+    }
+}
+
+/* Compute stack adjustments for all blocks by traversing DFS tree.
+   Return true when the adjustments on all incoming edges are consistent.
+   Heavily borrowed from pre_and_rev_post_order_compute.  */
+
+static bool
+vt_stack_adjustments (void)
+{
+  edge_iterator *stack;
+  int sp;
+
+  /* Initialize entry block.  */
+  VTI (ENTRY_BLOCK_PTR_FOR_FN (cfun))->visited = true;
+  VTI (ENTRY_BLOCK_PTR_FOR_FN (cfun))->in.stack_adjust =
+ INCOMING_FRAME_SP_OFFSET;
+  VTI (ENTRY_BLOCK_PTR_FOR_FN (cfun))->out.stack_adjust =
+ INCOMING_FRAME_SP_OFFSET;
+
+  /* Allocate stack for back-tracking up CFG.  */
+  stack = XNEWVEC (edge_iterator, n_basic_blocks_for_fn (cfun) + 1);
+  sp = 0;
+
+  /* Push the first edge on to the stack.  */
+  stack[sp++] = ei_start (ENTRY_BLOCK_PTR_FOR_FN (cfun)->succs);
+
+  while (sp)
+    {
+      edge_iterator ei;
+      basic_block src;
+      basic_block dest;
+
+      /* Look at the edge on the top of the stack.  */
+      ei = stack[sp - 1];
+      src = ei_edge (ei)->src;
+      dest = ei_edge (ei)->dest;
+
+      /* Check if the edge destination has been visited yet.  */
+      if (!VTI (dest)->visited)
+	{
+	  rtx insn;
+	  HOST_WIDE_INT pre, post, offset;
+	  VTI (dest)->visited = true;
+	  VTI (dest)->in.stack_adjust = offset = VTI (src)->out.stack_adjust;
+
+	  if (dest != EXIT_BLOCK_PTR_FOR_FN (cfun))
+	    for (insn = BB_HEAD (dest);
+		 insn != NEXT_INSN (BB_END (dest));
+		 insn = NEXT_INSN (insn))
+	      if (INSN_P (insn))
+		{
+		  insn_stack_adjust_offset_pre_post (insn, &pre, &post);
+		  offset += pre + post;
+		}
+
+	  VTI (dest)->out.stack_adjust = offset;
+
+	  if (EDGE_COUNT (dest->succs) > 0)
+	    /* Since the DEST node has been visited for the first
+	       time, check its successors.  */
+	    stack[sp++] = ei_start (dest->succs);
+	}
+      else
+	{
+	  /* We can end up with different stack adjustments for the exit block
+	     of a shrink-wrapped function if stack_adjust_offset_pre_post
+	     doesn't understand the rtx pattern used to restore the stack
+	     pointer in the epilogue.  For example, on s390(x), the stack
+	     pointer is often restored via a load-multiple instruction
+	     and so no stack_adjust offset is recorded for it.  This means
+	     that the stack offset at the end of the epilogue block is the
+	     the same as the offset before the epilogue, whereas other paths
+	     to the exit block will have the correct stack_adjust.
+
+	     It is safe to ignore these differences because (a) we never
+	     use the stack_adjust for the exit block in this pass and
+	     (b) dwarf2cfi checks whether the CFA notes in a shrink-wrapped
+	     function are correct.
+
+	     We must check whether the adjustments on other edges are
+	     the same though.  */
+	  if (dest != EXIT_BLOCK_PTR_FOR_FN (cfun)
+	      && VTI (dest)->in.stack_adjust != VTI (src)->out.stack_adjust)
+	    {
+	      free (stack);
+	      return false;
+	    }
+
+	  if (! ei_one_before_end_p (ei))
+	    /* Go to the next edge.  */
+	    ei_next (&stack[sp - 1]);
+	  else
+	    /* Return to previous level if there are no more edges.  */
+	    sp--;
+	}
+    }
+
+  free (stack);
+  return true;
+}
+
+/* arg_pointer_rtx resp. frame_pointer_rtx if stack_pointer_rtx or
+   hard_frame_pointer_rtx is being mapped to it and offset for it.  */
+static rtx cfa_base_rtx;
+static HOST_WIDE_INT cfa_base_offset;
+
+/* Compute a CFA-based value for an ADJUSTMENT made to stack_pointer_rtx
+   or hard_frame_pointer_rtx.  */
+
+static inline rtx
+compute_cfa_pointer (HOST_WIDE_INT adjustment)
+{
+  return plus_constant (Pmode, cfa_base_rtx, adjustment + cfa_base_offset);
+}
+
+/* Adjustment for hard_frame_pointer_rtx to cfa base reg,
+   or -1 if the replacement shouldn't be done.  */
+static HOST_WIDE_INT hard_frame_pointer_adjustment = -1;
+
+/* Data for adjust_mems callback.  */
+
+struct adjust_mem_data
+{
+  bool store;
+  enum machine_mode mem_mode;
+  HOST_WIDE_INT stack_adjust;
+  rtx side_effects;
+};
+
+/* Helper for adjust_mems.  Return 1 if *loc is unsuitable for
+   transformation of wider mode arithmetics to narrower mode,
+   -1 if it is suitable and subexpressions shouldn't be
+   traversed and 0 if it is suitable and subexpressions should
+   be traversed.  Called through for_each_rtx.  */
+
+static int
+use_narrower_mode_test (rtx *loc, void *data)
+{
+  rtx subreg = (rtx) data;
+
+  if (CONSTANT_P (*loc))
+    return -1;
+  switch (GET_CODE (*loc))
+    {
+    case REG:
+      if (cselib_lookup (*loc, GET_MODE (SUBREG_REG (subreg)), 0, VOIDmode))
+	return 1;
+      if (!validate_subreg (GET_MODE (subreg), GET_MODE (*loc),
+			    *loc, subreg_lowpart_offset (GET_MODE (subreg),
+							 GET_MODE (*loc))))
+	return 1;
+      return -1;
+    case PLUS:
+    case MINUS:
+    case MULT:
+      return 0;
+    case ASHIFT:
+      if (for_each_rtx (&XEXP (*loc, 0), use_narrower_mode_test, data))
+	return 1;
+      else
+	return -1;
+    default:
+      return 1;
+    }
+}
+
+/* Transform X into narrower mode MODE from wider mode WMODE.  */
+
+static rtx
+use_narrower_mode (rtx x, enum machine_mode mode, enum machine_mode wmode)
+{
+  rtx op0, op1;
+  if (CONSTANT_P (x))
+    return lowpart_subreg (mode, x, wmode);
+  switch (GET_CODE (x))
+    {
+    case REG:
+      return lowpart_subreg (mode, x, wmode);
+    case PLUS:
+    case MINUS:
+    case MULT:
+      op0 = use_narrower_mode (XEXP (x, 0), mode, wmode);
+      op1 = use_narrower_mode (XEXP (x, 1), mode, wmode);
+      return simplify_gen_binary (GET_CODE (x), mode, op0, op1);
+    case ASHIFT:
+      op0 = use_narrower_mode (XEXP (x, 0), mode, wmode);
+      return simplify_gen_binary (ASHIFT, mode, op0, XEXP (x, 1));
+    default:
+      gcc_unreachable ();
+    }
+}
+
+/* Helper function for adjusting used MEMs.  */
+
+static rtx
+adjust_mems (rtx loc, const_rtx old_rtx, void *data)
+{
+  struct adjust_mem_data *amd = (struct adjust_mem_data *) data;
+  rtx mem, addr = loc, tem;
+  enum machine_mode mem_mode_save;
+  bool store_save;
+  switch (GET_CODE (loc))
+    {
+    case REG:
+      /* Don't do any sp or fp replacements outside of MEM addresses
+         on the LHS.  */
+      if (amd->mem_mode == VOIDmode && amd->store)
+	return loc;
+      if (loc == stack_pointer_rtx
+	  && !frame_pointer_needed
+	  && cfa_base_rtx)
+	return compute_cfa_pointer (amd->stack_adjust);
+      else if (loc == hard_frame_pointer_rtx
+	       && frame_pointer_needed
+	       && hard_frame_pointer_adjustment != -1
+	       && cfa_base_rtx)
+	return compute_cfa_pointer (hard_frame_pointer_adjustment);
+      gcc_checking_assert (loc != virtual_incoming_args_rtx);
+      return loc;
+    case MEM:
+      mem = loc;
+      if (!amd->store)
+	{
+	  mem = targetm.delegitimize_address (mem);
+	  if (mem != loc && !MEM_P (mem))
+	    return simplify_replace_fn_rtx (mem, old_rtx, adjust_mems, data);
+	}
+
+      addr = XEXP (mem, 0);
+      mem_mode_save = amd->mem_mode;
+      amd->mem_mode = GET_MODE (mem);
+      store_save = amd->store;
+      amd->store = false;
+      addr = simplify_replace_fn_rtx (addr, old_rtx, adjust_mems, data);
+      amd->store = store_save;
+      amd->mem_mode = mem_mode_save;
+      if (mem == loc)
+	addr = targetm.delegitimize_address (addr);
+      if (addr != XEXP (mem, 0))
+	mem = replace_equiv_address_nv (mem, addr);
+      if (!amd->store)
+	mem = avoid_constant_pool_reference (mem);
+      return mem;
+    case PRE_INC:
+    case PRE_DEC:
+      addr = gen_rtx_PLUS (GET_MODE (loc), XEXP (loc, 0),
+			   gen_int_mode (GET_CODE (loc) == PRE_INC
+					 ? GET_MODE_SIZE (amd->mem_mode)
+					 : -GET_MODE_SIZE (amd->mem_mode),
+					 GET_MODE (loc)));
+    case POST_INC:
+    case POST_DEC:
+      if (addr == loc)
+	addr = XEXP (loc, 0);
+      gcc_assert (amd->mem_mode != VOIDmode && amd->mem_mode != BLKmode);
+      addr = simplify_replace_fn_rtx (addr, old_rtx, adjust_mems, data);
+      tem = gen_rtx_PLUS (GET_MODE (loc), XEXP (loc, 0),
+			  gen_int_mode ((GET_CODE (loc) == PRE_INC
+					 || GET_CODE (loc) == POST_INC)
+					? GET_MODE_SIZE (amd->mem_mode)
+					: -GET_MODE_SIZE (amd->mem_mode),
+					GET_MODE (loc)));
+      store_save = amd->store;
+      amd->store = false;
+      tem = simplify_replace_fn_rtx (tem, old_rtx, adjust_mems, data);
+      amd->store = store_save;
+      amd->side_effects = alloc_EXPR_LIST (0,
+					   gen_rtx_SET (VOIDmode,
+							XEXP (loc, 0), tem),
+					   amd->side_effects);
+      return addr;
+    case PRE_MODIFY:
+      addr = XEXP (loc, 1);
+    case POST_MODIFY:
+      if (addr == loc)
+	addr = XEXP (loc, 0);
+      gcc_assert (amd->mem_mode != VOIDmode);
+      addr = simplify_replace_fn_rtx (addr, old_rtx, adjust_mems, data);
+      store_save = amd->store;
+      amd->store = false;
+      tem = simplify_replace_fn_rtx (XEXP (loc, 1), old_rtx,
+				     adjust_mems, data);
+      amd->store = store_save;
+      amd->side_effects = alloc_EXPR_LIST (0,
+					   gen_rtx_SET (VOIDmode,
+							XEXP (loc, 0), tem),
+					   amd->side_effects);
+      return addr;
+    case SUBREG:
+      /* First try without delegitimization of whole MEMs and
+	 avoid_constant_pool_reference, which is more likely to succeed.  */
+      store_save = amd->store;
+      amd->store = true;
+      addr = simplify_replace_fn_rtx (SUBREG_REG (loc), old_rtx, adjust_mems,
+				      data);
+      amd->store = store_save;
+      mem = simplify_replace_fn_rtx (addr, old_rtx, adjust_mems, data);
+      if (mem == SUBREG_REG (loc))
+	{
+	  tem = loc;
+	  goto finish_subreg;
+	}
+      tem = simplify_gen_subreg (GET_MODE (loc), mem,
+				 GET_MODE (SUBREG_REG (loc)),
+				 SUBREG_BYTE (loc));
+      if (tem)
+	goto finish_subreg;
+      tem = simplify_gen_subreg (GET_MODE (loc), addr,
+				 GET_MODE (SUBREG_REG (loc)),
+				 SUBREG_BYTE (loc));
+      if (tem == NULL_RTX)
+	tem = gen_rtx_raw_SUBREG (GET_MODE (loc), addr, SUBREG_BYTE (loc));
+    finish_subreg:
+      if (MAY_HAVE_DEBUG_INSNS
+	  && GET_CODE (tem) == SUBREG
+	  && (GET_CODE (SUBREG_REG (tem)) == PLUS
+	      || GET_CODE (SUBREG_REG (tem)) == MINUS
+	      || GET_CODE (SUBREG_REG (tem)) == MULT
+	      || GET_CODE (SUBREG_REG (tem)) == ASHIFT)
+	  && GET_MODE_CLASS (GET_MODE (tem)) == MODE_INT
+	  && GET_MODE_CLASS (GET_MODE (SUBREG_REG (tem))) == MODE_INT
+	  && GET_MODE_SIZE (GET_MODE (tem))
+	     < GET_MODE_SIZE (GET_MODE (SUBREG_REG (tem)))
+	  && subreg_lowpart_p (tem)
+	  && !for_each_rtx (&SUBREG_REG (tem), use_narrower_mode_test, tem))
+	return use_narrower_mode (SUBREG_REG (tem), GET_MODE (tem),
+				  GET_MODE (SUBREG_REG (tem)));
+      return tem;
+    case ASM_OPERANDS:
+      /* Don't do any replacements in second and following
+	 ASM_OPERANDS of inline-asm with multiple sets.
+	 ASM_OPERANDS_INPUT_VEC, ASM_OPERANDS_INPUT_CONSTRAINT_VEC
+	 and ASM_OPERANDS_LABEL_VEC need to be equal between
+	 all the ASM_OPERANDs in the insn and adjust_insn will
+	 fix this up.  */
+      if (ASM_OPERANDS_OUTPUT_IDX (loc) != 0)
+	return loc;
+      break;
+    default:
+      break;
+    }
+  return NULL_RTX;
+}
+
+/* Helper function for replacement of uses.  */
+
+static void
+adjust_mem_uses (rtx *x, void *data)
+{
+  rtx new_x = simplify_replace_fn_rtx (*x, NULL_RTX, adjust_mems, data);
+  if (new_x != *x)
+    validate_change (NULL_RTX, x, new_x, true);
+}
+
+/* Helper function for replacement of stores.  */
+
+static void
+adjust_mem_stores (rtx loc, const_rtx expr, void *data)
+{
+  if (MEM_P (loc))
+    {
+      rtx new_dest = simplify_replace_fn_rtx (SET_DEST (expr), NULL_RTX,
+					      adjust_mems, data);
+      if (new_dest != SET_DEST (expr))
+	{
+	  rtx xexpr = CONST_CAST_RTX (expr);
+	  validate_change (NULL_RTX, &SET_DEST (xexpr), new_dest, true);
+	}
+    }
+}
+
+/* Simplify INSN.  Remove all {PRE,POST}_{INC,DEC,MODIFY} rtxes,
+   replace them with their value in the insn and add the side-effects
+   as other sets to the insn.  */
+
+static void
+adjust_insn (basic_block bb, rtx insn)
+{
+  struct adjust_mem_data amd;
+  rtx set;
+
+#ifdef HAVE_window_save
+  /* If the target machine has an explicit window save instruction, the
+     transformation OUTGOING_REGNO -> INCOMING_REGNO is done there.  */
+  if (RTX_FRAME_RELATED_P (insn)
+      && find_reg_note (insn, REG_CFA_WINDOW_SAVE, NULL_RTX))
+    {
+      unsigned int i, nregs = vec_safe_length (windowed_parm_regs);
+      rtx rtl = gen_rtx_PARALLEL (VOIDmode, rtvec_alloc (nregs * 2));
+      parm_reg_t *p;
+
+      FOR_EACH_VEC_SAFE_ELT (windowed_parm_regs, i, p)
+	{
+	  XVECEXP (rtl, 0, i * 2)
+	    = gen_rtx_SET (VOIDmode, p->incoming, p->outgoing);
+	  /* Do not clobber the attached DECL, but only the REG.  */
+	  XVECEXP (rtl, 0, i * 2 + 1)
+	    = gen_rtx_CLOBBER (GET_MODE (p->outgoing),
+			       gen_raw_REG (GET_MODE (p->outgoing),
+					    REGNO (p->outgoing)));
+	}
+
+      validate_change (NULL_RTX, &PATTERN (insn), rtl, true);
+      return;
+    }
+#endif
+
+  amd.mem_mode = VOIDmode;
+  amd.stack_adjust = -VTI (bb)->out.stack_adjust;
+  amd.side_effects = NULL_RTX;
+
+  amd.store = true;
+  note_stores (PATTERN (insn), adjust_mem_stores, &amd);
+
+  amd.store = false;
+  if (GET_CODE (PATTERN (insn)) == PARALLEL
+      && asm_noperands (PATTERN (insn)) > 0
+      && GET_CODE (XVECEXP (PATTERN (insn), 0, 0)) == SET)
+    {
+      rtx body, set0;
+      int i;
+
+      /* inline-asm with multiple sets is tiny bit more complicated,
+	 because the 3 vectors in ASM_OPERANDS need to be shared between
+	 all ASM_OPERANDS in the instruction.  adjust_mems will
+	 not touch ASM_OPERANDS other than the first one, asm_noperands
+	 test above needs to be called before that (otherwise it would fail)
+	 and afterwards this code fixes it up.  */
+      note_uses (&PATTERN (insn), adjust_mem_uses, &amd);
+      body = PATTERN (insn);
+      set0 = XVECEXP (body, 0, 0);
+      gcc_checking_assert (GET_CODE (set0) == SET
+			   && GET_CODE (SET_SRC (set0)) == ASM_OPERANDS
+			   && ASM_OPERANDS_OUTPUT_IDX (SET_SRC (set0)) == 0);
+      for (i = 1; i < XVECLEN (body, 0); i++)
+	if (GET_CODE (XVECEXP (body, 0, i)) != SET)
+	  break;
+	else
+	  {
+	    set = XVECEXP (body, 0, i);
+	    gcc_checking_assert (GET_CODE (SET_SRC (set)) == ASM_OPERANDS
+				 && ASM_OPERANDS_OUTPUT_IDX (SET_SRC (set))
+				    == i);
+	    if (ASM_OPERANDS_INPUT_VEC (SET_SRC (set))
+		!= ASM_OPERANDS_INPUT_VEC (SET_SRC (set0))
+		|| ASM_OPERANDS_INPUT_CONSTRAINT_VEC (SET_SRC (set))
+		   != ASM_OPERANDS_INPUT_CONSTRAINT_VEC (SET_SRC (set0))
+		|| ASM_OPERANDS_LABEL_VEC (SET_SRC (set))
+		   != ASM_OPERANDS_LABEL_VEC (SET_SRC (set0)))
+	      {
+		rtx newsrc = shallow_copy_rtx (SET_SRC (set));
+		ASM_OPERANDS_INPUT_VEC (newsrc)
+		  = ASM_OPERANDS_INPUT_VEC (SET_SRC (set0));
+		ASM_OPERANDS_INPUT_CONSTRAINT_VEC (newsrc)
+		  = ASM_OPERANDS_INPUT_CONSTRAINT_VEC (SET_SRC (set0));
+		ASM_OPERANDS_LABEL_VEC (newsrc)
+		  = ASM_OPERANDS_LABEL_VEC (SET_SRC (set0));
+		validate_change (NULL_RTX, &SET_SRC (set), newsrc, true);
+	      }
+	  }
+    }
+  else
+    note_uses (&PATTERN (insn), adjust_mem_uses, &amd);
+
+  /* For read-only MEMs containing some constant, prefer those
+     constants.  */
+  set = single_set (insn);
+  if (set && MEM_P (SET_SRC (set)) && MEM_READONLY_P (SET_SRC (set)))
+    {
+      rtx note = find_reg_equal_equiv_note (insn);
+
+      if (note && CONSTANT_P (XEXP (note, 0)))
+	validate_change (NULL_RTX, &SET_SRC (set), XEXP (note, 0), true);
+    }
+
+  if (amd.side_effects)
+    {
+      rtx *pat, new_pat, s;
+      int i, oldn, newn;
+
+      pat = &PATTERN (insn);
+      if (GET_CODE (*pat) == COND_EXEC)
+	pat = &COND_EXEC_CODE (*pat);
+      if (GET_CODE (*pat) == PARALLEL)
+	oldn = XVECLEN (*pat, 0);
+      else
+	oldn = 1;
+      for (s = amd.side_effects, newn = 0; s; newn++)
+	s = XEXP (s, 1);
+      new_pat = gen_rtx_PARALLEL (VOIDmode, rtvec_alloc (oldn + newn));
+      if (GET_CODE (*pat) == PARALLEL)
+	for (i = 0; i < oldn; i++)
+	  XVECEXP (new_pat, 0, i) = XVECEXP (*pat, 0, i);
+      else
+	XVECEXP (new_pat, 0, 0) = *pat;
+      for (s = amd.side_effects, i = oldn; i < oldn + newn; i++, s = XEXP (s, 1))
+	XVECEXP (new_pat, 0, i) = XEXP (s, 0);
+      free_EXPR_LIST_list (&amd.side_effects);
+      validate_change (NULL_RTX, pat, new_pat, true);
+    }
+}
+
+/* Return the DEBUG_EXPR of a DEBUG_EXPR_DECL or the VALUE in DV.  */
+static inline rtx
+dv_as_rtx (decl_or_value dv)
+{
+  tree decl;
+
+  if (dv_is_value_p (dv))
+    return dv_as_value (dv);
+
+  decl = dv_as_decl (dv);
+
+  gcc_checking_assert (TREE_CODE (decl) == DEBUG_EXPR_DECL);
+  return DECL_RTL_KNOWN_SET (decl);
+}
+
+/* Return nonzero if a decl_or_value must not have more than one
+   variable part.  The returned value discriminates among various
+   kinds of one-part DVs ccording to enum onepart_enum.  */
+static inline onepart_enum_t
+dv_onepart_p (decl_or_value dv)
+{
+  tree decl;
+
+  if (!MAY_HAVE_DEBUG_INSNS)
+    return NOT_ONEPART;
+
+  if (dv_is_value_p (dv))
+    return ONEPART_VALUE;
+
+  decl = dv_as_decl (dv);
+
+  if (TREE_CODE (decl) == DEBUG_EXPR_DECL)
+    return ONEPART_DEXPR;
+
+  if (target_for_debug_bind (decl) != NULL_TREE)
+    return ONEPART_VDECL;
+
+  return NOT_ONEPART;
+}
+
+/* Return the variable pool to be used for a dv of type ONEPART.  */
+static inline alloc_pool
+onepart_pool (onepart_enum_t onepart)
+{
+  return onepart ? valvar_pool : var_pool;
+}
+
+/* Build a decl_or_value out of a decl.  */
+static inline decl_or_value
+dv_from_decl (tree decl)
+{
+  decl_or_value dv;
+  dv = decl;
+  gcc_checking_assert (dv_is_decl_p (dv));
+  return dv;
+}
+
+/* Build a decl_or_value out of a value.  */
+static inline decl_or_value
+dv_from_value (rtx value)
+{
+  decl_or_value dv;
+  dv = value;
+  gcc_checking_assert (dv_is_value_p (dv));
+  return dv;
+}
+
+/* Return a value or the decl of a debug_expr as a decl_or_value.  */
+static inline decl_or_value
+dv_from_rtx (rtx x)
+{
+  decl_or_value dv;
+
+  switch (GET_CODE (x))
+    {
+    case DEBUG_EXPR:
+      dv = dv_from_decl (DEBUG_EXPR_TREE_DECL (x));
+      gcc_checking_assert (DECL_RTL_KNOWN_SET (DEBUG_EXPR_TREE_DECL (x)) == x);
+      break;
+
+    case VALUE:
+      dv = dv_from_value (x);
+      break;
+
+    default:
+      gcc_unreachable ();
+    }
+
+  return dv;
+}
+
+extern void debug_dv (decl_or_value dv);
+
+DEBUG_FUNCTION void
+debug_dv (decl_or_value dv)
+{
+  if (dv_is_value_p (dv))
+    debug_rtx (dv_as_value (dv));
+  else
+    debug_generic_stmt (dv_as_decl (dv));
+}
+
+static void loc_exp_dep_clear (variable var);
+
+/* Free the element of VARIABLE_HTAB (its type is struct variable_def).  */
+
+static void
+variable_htab_free (void *elem)
+{
+  int i;
+  variable var = (variable) elem;
+  location_chain node, next;
+
+  gcc_checking_assert (var->refcount > 0);
+
+  var->refcount--;
+  if (var->refcount > 0)
+    return;
+
+  for (i = 0; i < var->n_var_parts; i++)
+    {
+      for (node = var->var_part[i].loc_chain; node; node = next)
+	{
+	  next = node->next;
+	  pool_free (loc_chain_pool, node);
+	}
+      var->var_part[i].loc_chain = NULL;
+    }
+  if (var->onepart && VAR_LOC_1PAUX (var))
+    {
+      loc_exp_dep_clear (var);
+      if (VAR_LOC_DEP_LST (var))
+	VAR_LOC_DEP_LST (var)->pprev = NULL;
+      XDELETE (VAR_LOC_1PAUX (var));
+      /* These may be reused across functions, so reset
+	 e.g. NO_LOC_P.  */
+      if (var->onepart == ONEPART_DEXPR)
+	set_dv_changed (var->dv, true);
+    }
+  pool_free (onepart_pool (var->onepart), var);
+}
+
+/* Initialize the set (array) SET of attrs to empty lists.  */
+
+static void
+init_attrs_list_set (attrs *set)
+{
+  int i;
+
+  for (i = 0; i < FIRST_PSEUDO_REGISTER; i++)
+    set[i] = NULL;
+}
+
+/* Make the list *LISTP empty.  */
+
+static void
+attrs_list_clear (attrs *listp)
+{
+  attrs list, next;
+
+  for (list = *listp; list; list = next)
+    {
+      next = list->next;
+      pool_free (attrs_pool, list);
+    }
+  *listp = NULL;
+}
+
+/* Return true if the pair of DECL and OFFSET is the member of the LIST.  */
+
+static attrs
+attrs_list_member (attrs list, decl_or_value dv, HOST_WIDE_INT offset)
+{
+  for (; list; list = list->next)
+    if (dv_as_opaque (list->dv) == dv_as_opaque (dv) && list->offset == offset)
+      return list;
+  return NULL;
+}
+
+/* Insert the triplet DECL, OFFSET, LOC to the list *LISTP.  */
+
+static void
+attrs_list_insert (attrs *listp, decl_or_value dv,
+		   HOST_WIDE_INT offset, rtx loc)
+{
+  attrs list;
+
+  list = (attrs) pool_alloc (attrs_pool);
+  list->loc = loc;
+  list->dv = dv;
+  list->offset = offset;
+  list->next = *listp;
+  *listp = list;
+}
+
+/* Copy all nodes from SRC and create a list *DSTP of the copies.  */
+
+static void
+attrs_list_copy (attrs *dstp, attrs src)
+{
+  attrs n;
+
+  attrs_list_clear (dstp);
+  for (; src; src = src->next)
+    {
+      n = (attrs) pool_alloc (attrs_pool);
+      n->loc = src->loc;
+      n->dv = src->dv;
+      n->offset = src->offset;
+      n->next = *dstp;
+      *dstp = n;
+    }
+}
+
+/* Add all nodes from SRC which are not in *DSTP to *DSTP.  */
+
+static void
+attrs_list_union (attrs *dstp, attrs src)
+{
+  for (; src; src = src->next)
+    {
+      if (!attrs_list_member (*dstp, src->dv, src->offset))
+	attrs_list_insert (dstp, src->dv, src->offset, src->loc);
+    }
+}
+
+/* Combine nodes that are not onepart nodes from SRC and SRC2 into
+   *DSTP.  */
+
+static void
+attrs_list_mpdv_union (attrs *dstp, attrs src, attrs src2)
+{
+  gcc_assert (!*dstp);
+  for (; src; src = src->next)
+    {
+      if (!dv_onepart_p (src->dv))
+	attrs_list_insert (dstp, src->dv, src->offset, src->loc);
+    }
+  for (src = src2; src; src = src->next)
+    {
+      if (!dv_onepart_p (src->dv)
+	  && !attrs_list_member (*dstp, src->dv, src->offset))
+	attrs_list_insert (dstp, src->dv, src->offset, src->loc);
+    }
+}
+
+/* Shared hashtable support.  */
+
+/* Return true if VARS is shared.  */
+
+static inline bool
+shared_hash_shared (shared_hash vars)
+{
+  return vars->refcount > 1;
+}
+
+/* Return the hash table for VARS.  */
+
+static inline variable_table_type
+shared_hash_htab (shared_hash vars)
+{
+  return vars->htab;
+}
+
+/* Return true if VAR is shared, or maybe because VARS is shared.  */
+
+static inline bool
+shared_var_p (variable var, shared_hash vars)
+{
+  /* Don't count an entry in the changed_variables table as a duplicate.  */
+  return ((var->refcount > 1 + (int) var->in_changed_variables)
+	  || shared_hash_shared (vars));
+}
+
+/* Copy variables into a new hash table.  */
+
+static shared_hash
+shared_hash_unshare (shared_hash vars)
+{
+  shared_hash new_vars = (shared_hash) pool_alloc (shared_hash_pool);
+  gcc_assert (vars->refcount > 1);
+  new_vars->refcount = 1;
+  new_vars->htab.create (vars->htab.elements () + 3);
+  vars_copy (new_vars->htab, vars->htab);
+  vars->refcount--;
+  return new_vars;
+}
+
+/* Increment reference counter on VARS and return it.  */
+
+static inline shared_hash
+shared_hash_copy (shared_hash vars)
+{
+  vars->refcount++;
+  return vars;
+}
+
+/* Decrement reference counter and destroy hash table if not shared
+   anymore.  */
+
+static void
+shared_hash_destroy (shared_hash vars)
+{
+  gcc_checking_assert (vars->refcount > 0);
+  if (--vars->refcount == 0)
+    {
+      vars->htab.dispose ();
+      pool_free (shared_hash_pool, vars);
+    }
+}
+
+/* Unshare *PVARS if shared and return slot for DV.  If INS is
+   INSERT, insert it if not already present.  */
+
+static inline variable_def **
+shared_hash_find_slot_unshare_1 (shared_hash *pvars, decl_or_value dv,
+				 hashval_t dvhash, enum insert_option ins)
+{
+  if (shared_hash_shared (*pvars))
+    *pvars = shared_hash_unshare (*pvars);
+  return shared_hash_htab (*pvars).find_slot_with_hash (dv, dvhash, ins);
+}
+
+static inline variable_def **
+shared_hash_find_slot_unshare (shared_hash *pvars, decl_or_value dv,
+			       enum insert_option ins)
+{
+  return shared_hash_find_slot_unshare_1 (pvars, dv, dv_htab_hash (dv), ins);
+}
+
+/* Return slot for DV, if it is already present in the hash table.
+   If it is not present, insert it only VARS is not shared, otherwise
+   return NULL.  */
+
+static inline variable_def **
+shared_hash_find_slot_1 (shared_hash vars, decl_or_value dv, hashval_t dvhash)
+{
+  return shared_hash_htab (vars).find_slot_with_hash (dv, dvhash,
+						      shared_hash_shared (vars)
+						      ? NO_INSERT : INSERT);
+}
+
+static inline variable_def **
+shared_hash_find_slot (shared_hash vars, decl_or_value dv)
+{
+  return shared_hash_find_slot_1 (vars, dv, dv_htab_hash (dv));
+}
+
+/* Return slot for DV only if it is already present in the hash table.  */
+
+static inline variable_def **
+shared_hash_find_slot_noinsert_1 (shared_hash vars, decl_or_value dv,
+				  hashval_t dvhash)
+{
+  return shared_hash_htab (vars).find_slot_with_hash (dv, dvhash, NO_INSERT);
+}
+
+static inline variable_def **
+shared_hash_find_slot_noinsert (shared_hash vars, decl_or_value dv)
+{
+  return shared_hash_find_slot_noinsert_1 (vars, dv, dv_htab_hash (dv));
+}
+
+/* Return variable for DV or NULL if not already present in the hash
+   table.  */
+
+static inline variable
+shared_hash_find_1 (shared_hash vars, decl_or_value dv, hashval_t dvhash)
+{
+  return shared_hash_htab (vars).find_with_hash (dv, dvhash);
+}
+
+static inline variable
+shared_hash_find (shared_hash vars, decl_or_value dv)
+{
+  return shared_hash_find_1 (vars, dv, dv_htab_hash (dv));
+}
+
+/* Return true if TVAL is better than CVAL as a canonival value.  We
+   choose lowest-numbered VALUEs, using the RTX address as a
+   tie-breaker.  The idea is to arrange them into a star topology,
+   such that all of them are at most one step away from the canonical
+   value, and the canonical value has backlinks to all of them, in
+   addition to all the actual locations.  We don't enforce this
+   topology throughout the entire dataflow analysis, though.
+ */
+
+static inline bool
+canon_value_cmp (rtx tval, rtx cval)
+{
+  return !cval
+    || CSELIB_VAL_PTR (tval)->uid < CSELIB_VAL_PTR (cval)->uid;
+}
+
+static bool dst_can_be_shared;
+
+/* Return a copy of a variable VAR and insert it to dataflow set SET.  */
+
+static variable_def **
+unshare_variable (dataflow_set *set, variable_def **slot, variable var,
+		  enum var_init_status initialized)
+{
+  variable new_var;
+  int i;
+
+  new_var = (variable) pool_alloc (onepart_pool (var->onepart));
+  new_var->dv = var->dv;
+  new_var->refcount = 1;
+  var->refcount--;
+  new_var->n_var_parts = var->n_var_parts;
+  new_var->onepart = var->onepart;
+  new_var->in_changed_variables = false;
+
+  if (! flag_var_tracking_uninit)
+    initialized = VAR_INIT_STATUS_INITIALIZED;
+
+  for (i = 0; i < var->n_var_parts; i++)
+    {
+      location_chain node;
+      location_chain *nextp;
+
+      if (i == 0 && var->onepart)
+	{
+	  /* One-part auxiliary data is only used while emitting
+	     notes, so propagate it to the new variable in the active
+	     dataflow set.  If we're not emitting notes, this will be
+	     a no-op.  */
+	  gcc_checking_assert (!VAR_LOC_1PAUX (var) || emit_notes);
+	  VAR_LOC_1PAUX (new_var) = VAR_LOC_1PAUX (var);
+	  VAR_LOC_1PAUX (var) = NULL;
+	}
+      else
+	VAR_PART_OFFSET (new_var, i) = VAR_PART_OFFSET (var, i);
+      nextp = &new_var->var_part[i].loc_chain;
+      for (node = var->var_part[i].loc_chain; node; node = node->next)
+	{
+	  location_chain new_lc;
+
+	  new_lc = (location_chain) pool_alloc (loc_chain_pool);
+	  new_lc->next = NULL;
+	  if (node->init > initialized)
+	    new_lc->init = node->init;
+	  else
+	    new_lc->init = initialized;
+	  if (node->set_src && !(MEM_P (node->set_src)))
+	    new_lc->set_src = node->set_src;
+	  else
+	    new_lc->set_src = NULL;
+	  new_lc->loc = node->loc;
+
+	  *nextp = new_lc;
+	  nextp = &new_lc->next;
+	}
+
+      new_var->var_part[i].cur_loc = var->var_part[i].cur_loc;
+    }
+
+  dst_can_be_shared = false;
+  if (shared_hash_shared (set->vars))
+    slot = shared_hash_find_slot_unshare (&set->vars, var->dv, NO_INSERT);
+  else if (set->traversed_vars && set->vars != set->traversed_vars)
+    slot = shared_hash_find_slot_noinsert (set->vars, var->dv);
+  *slot = new_var;
+  if (var->in_changed_variables)
+    {
+      variable_def **cslot
+	= changed_variables.find_slot_with_hash (var->dv,
+				    dv_htab_hash (var->dv), NO_INSERT);
+      gcc_assert (*cslot == (void *) var);
+      var->in_changed_variables = false;
+      variable_htab_free (var);
+      *cslot = new_var;
+      new_var->in_changed_variables = true;
+    }
+  return slot;
+}
+
+/* Copy all variables from hash table SRC to hash table DST.  */
+
+static void
+vars_copy (variable_table_type dst, variable_table_type src)
+{
+  variable_iterator_type hi;
+  variable var;
+
+  FOR_EACH_HASH_TABLE_ELEMENT (src, var, variable, hi)
+    {
+      variable_def **dstp;
+      var->refcount++;
+      dstp = dst.find_slot_with_hash (var->dv, dv_htab_hash (var->dv), INSERT);
+      *dstp = var;
+    }
+}
+
+/* Map a decl to its main debug decl.  */
+
+static inline tree
+var_debug_decl (tree decl)
+{
+  if (decl && TREE_CODE (decl) == VAR_DECL
+      && DECL_HAS_DEBUG_EXPR_P (decl))
+    {
+      tree debugdecl = DECL_DEBUG_EXPR (decl);
+      if (DECL_P (debugdecl))
+	decl = debugdecl;
+    }
+
+  return decl;
+}
+
+/* Set the register LOC to contain DV, OFFSET.  */
+
+static void
+var_reg_decl_set (dataflow_set *set, rtx loc, enum var_init_status initialized,
+		  decl_or_value dv, HOST_WIDE_INT offset, rtx set_src,
+		  enum insert_option iopt)
+{
+  attrs node;
+  bool decl_p = dv_is_decl_p (dv);
+
+  if (decl_p)
+    dv = dv_from_decl (var_debug_decl (dv_as_decl (dv)));
+
+  for (node = set->regs[REGNO (loc)]; node; node = node->next)
+    if (dv_as_opaque (node->dv) == dv_as_opaque (dv)
+	&& node->offset == offset)
+      break;
+  if (!node)
+    attrs_list_insert (&set->regs[REGNO (loc)], dv, offset, loc);
+  set_variable_part (set, loc, dv, offset, initialized, set_src, iopt);
+}
+
+/* Set the register to contain REG_EXPR (LOC), REG_OFFSET (LOC).  */
+
+static void
+var_reg_set (dataflow_set *set, rtx loc, enum var_init_status initialized,
+	     rtx set_src)
+{
+  tree decl = REG_EXPR (loc);
+  HOST_WIDE_INT offset = REG_OFFSET (loc);
+
+  var_reg_decl_set (set, loc, initialized,
+		    dv_from_decl (decl), offset, set_src, INSERT);
+}
+
+static enum var_init_status
+get_init_value (dataflow_set *set, rtx loc, decl_or_value dv)
+{
+  variable var;
+  int i;
+  enum var_init_status ret_val = VAR_INIT_STATUS_UNKNOWN;
+
+  if (! flag_var_tracking_uninit)
+    return VAR_INIT_STATUS_INITIALIZED;
+
+  var = shared_hash_find (set->vars, dv);
+  if (var)
+    {
+      for (i = 0; i < var->n_var_parts && ret_val == VAR_INIT_STATUS_UNKNOWN; i++)
+	{
+	  location_chain nextp;
+	  for (nextp = var->var_part[i].loc_chain; nextp; nextp = nextp->next)
+	    if (rtx_equal_p (nextp->loc, loc))
+	      {
+		ret_val = nextp->init;
+		break;
+	      }
+	}
+    }
+
+  return ret_val;
+}
+
+/* Delete current content of register LOC in dataflow set SET and set
+   the register to contain REG_EXPR (LOC), REG_OFFSET (LOC).  If
+   MODIFY is true, any other live copies of the same variable part are
+   also deleted from the dataflow set, otherwise the variable part is
+   assumed to be copied from another location holding the same
+   part.  */
+
+static void
+var_reg_delete_and_set (dataflow_set *set, rtx loc, bool modify,
+			enum var_init_status initialized, rtx set_src)
+{
+  tree decl = REG_EXPR (loc);
+  HOST_WIDE_INT offset = REG_OFFSET (loc);
+  attrs node, next;
+  attrs *nextp;
+
+  decl = var_debug_decl (decl);
+
+  if (initialized == VAR_INIT_STATUS_UNKNOWN)
+    initialized = get_init_value (set, loc, dv_from_decl (decl));
+
+  nextp = &set->regs[REGNO (loc)];
+  for (node = *nextp; node; node = next)
+    {
+      next = node->next;
+      if (dv_as_opaque (node->dv) != decl || node->offset != offset)
+	{
+	  delete_variable_part (set, node->loc, node->dv, node->offset);
+	  pool_free (attrs_pool, node);
+	  *nextp = next;
+	}
+      else
+	{
+	  node->loc = loc;
+	  nextp = &node->next;
+	}
+    }
+  if (modify)
+    clobber_variable_part (set, loc, dv_from_decl (decl), offset, set_src);
+  var_reg_set (set, loc, initialized, set_src);
+}
+
+/* Delete the association of register LOC in dataflow set SET with any
+   variables that aren't onepart.  If CLOBBER is true, also delete any
+   other live copies of the same variable part, and delete the
+   association with onepart dvs too.  */
+
+static void
+var_reg_delete (dataflow_set *set, rtx loc, bool clobber)
+{
+  attrs *nextp = &set->regs[REGNO (loc)];
+  attrs node, next;
+
+  if (clobber)
+    {
+      tree decl = REG_EXPR (loc);
+      HOST_WIDE_INT offset = REG_OFFSET (loc);
+
+      decl = var_debug_decl (decl);
+
+      clobber_variable_part (set, NULL, dv_from_decl (decl), offset, NULL);
+    }
+
+  for (node = *nextp; node; node = next)
+    {
+      next = node->next;
+      if (clobber || !dv_onepart_p (node->dv))
+	{
+	  delete_variable_part (set, node->loc, node->dv, node->offset);
+	  pool_free (attrs_pool, node);
+	  *nextp = next;
+	}
+      else
+	nextp = &node->next;
+    }
+}
+
+/* Delete content of register with number REGNO in dataflow set SET.  */
+
+static void
+var_regno_delete (dataflow_set *set, int regno)
+{
+  attrs *reg = &set->regs[regno];
+  attrs node, next;
+
+  for (node = *reg; node; node = next)
+    {
+      next = node->next;
+      delete_variable_part (set, node->loc, node->dv, node->offset);
+      pool_free (attrs_pool, node);
+    }
+  *reg = NULL;
+}
+
+/* Return true if I is the negated value of a power of two.  */
+static bool
+negative_power_of_two_p (HOST_WIDE_INT i)
+{
+  unsigned HOST_WIDE_INT x = -(unsigned HOST_WIDE_INT)i;
+  return x == (x & -x);
+}
+
+/* Strip constant offsets and alignments off of LOC.  Return the base
+   expression.  */
+
+static rtx
+vt_get_canonicalize_base (rtx loc)
+{
+  while ((GET_CODE (loc) == PLUS
+	  || GET_CODE (loc) == AND)
+	 && GET_CODE (XEXP (loc, 1)) == CONST_INT
+	 && (GET_CODE (loc) != AND
+	     || negative_power_of_two_p (INTVAL (XEXP (loc, 1)))))
+    loc = XEXP (loc, 0);
+
+  return loc;
+}
+
+/* This caches canonicalized addresses for VALUEs, computed using
+   information in the global cselib table.  */
+static struct pointer_map_t *global_get_addr_cache;
+
+/* This caches canonicalized addresses for VALUEs, computed using
+   information from the global cache and information pertaining to a
+   basic block being analyzed.  */
+static struct pointer_map_t *local_get_addr_cache;
+
+static rtx vt_canonicalize_addr (dataflow_set *, rtx);
+
+/* Return the canonical address for LOC, that must be a VALUE, using a
+   cached global equivalence or computing it and storing it in the
+   global cache.  */
+
+static rtx
+get_addr_from_global_cache (rtx const loc)
+{
+  rtx x;
+  void **slot;
+
+  gcc_checking_assert (GET_CODE (loc) == VALUE);
+  
+  slot = pointer_map_insert (global_get_addr_cache, loc);
+  if (*slot)
+    return (rtx)*slot;
+
+  x = canon_rtx (get_addr (loc));
+
+  /* Tentative, avoiding infinite recursion.  */
+  *slot = x;
+
+  if (x != loc)
+    {
+      rtx nx = vt_canonicalize_addr (NULL, x);
+      if (nx != x)
+	{
+	  /* The table may have moved during recursion, recompute
+	     SLOT.  */
+	  slot = pointer_map_contains (global_get_addr_cache, loc);
+	  *slot = x = nx;
+	}
+    }
+
+  return x;
+}
+
+/* Return the canonical address for LOC, that must be a VALUE, using a
+   cached local equivalence or computing it and storing it in the
+   local cache.  */
+
+static rtx
+get_addr_from_local_cache (dataflow_set *set, rtx const loc)
+{
+  rtx x;
+  void **slot;
+  decl_or_value dv;
+  variable var;
+  location_chain l;
+
+  gcc_checking_assert (GET_CODE (loc) == VALUE);
+  
+  slot = pointer_map_insert (local_get_addr_cache, loc);
+  if (*slot)
+    return (rtx)*slot;
+
+  x = get_addr_from_global_cache (loc);
+  
+  /* Tentative, avoiding infinite recursion.  */
+  *slot = x;
+
+  /* Recurse to cache local expansion of X, or if we need to search
+     for a VALUE in the expansion.  */
+  if (x != loc)
+    {
+      rtx nx = vt_canonicalize_addr (set, x);
+      if (nx != x)
+	{
+	  slot = pointer_map_contains (local_get_addr_cache, loc);
+	  *slot = x = nx;
+	}
+      return x;
+    }
+
+  dv = dv_from_rtx (x);
+  var = shared_hash_find (set->vars, dv);
+  if (!var)
+    return x;
+
+  /* Look for an improved equivalent expression.  */
+  for (l = var->var_part[0].loc_chain; l; l = l->next)
+    {
+      rtx base = vt_get_canonicalize_base (l->loc);
+      if (GET_CODE (base) == VALUE
+	  && canon_value_cmp (base, loc))
+	{
+	  rtx nx = vt_canonicalize_addr (set, l->loc);
+	  if (x != nx)
+	    {
+	      slot = pointer_map_contains (local_get_addr_cache, loc);
+	      *slot = x = nx;
+	    }
+	  break;
+	}
+    }
+
+  return x;
+}
+
+/* Canonicalize LOC using equivalences from SET in addition to those
+   in the cselib static table.  It expects a VALUE-based expression,
+   and it will only substitute VALUEs with other VALUEs or
+   function-global equivalences, so that, if two addresses have base
+   VALUEs that are locally or globally related in ways that
+   memrefs_conflict_p cares about, they will both canonicalize to
+   expressions that have the same base VALUE.
+
+   The use of VALUEs as canonical base addresses enables the canonical
+   RTXs to remain unchanged globally, if they resolve to a constant,
+   or throughout a basic block otherwise, so that they can be cached
+   and the cache needs not be invalidated when REGs, MEMs or such
+   change.  */
+
+static rtx
+vt_canonicalize_addr (dataflow_set *set, rtx oloc)
+{
+  HOST_WIDE_INT ofst = 0;
+  enum machine_mode mode = GET_MODE (oloc);
+  rtx loc = oloc;
+  rtx x;
+  bool retry = true;
+
+  while (retry)
+    {
+      while (GET_CODE (loc) == PLUS
+	     && GET_CODE (XEXP (loc, 1)) == CONST_INT)
+	{
+	  ofst += INTVAL (XEXP (loc, 1));
+	  loc = XEXP (loc, 0);
+	}
+
+      /* Alignment operations can't normally be combined, so just
+	 canonicalize the base and we're done.  We'll normally have
+	 only one stack alignment anyway.  */
+      if (GET_CODE (loc) == AND
+	  && GET_CODE (XEXP (loc, 1)) == CONST_INT
+	  && negative_power_of_two_p (INTVAL (XEXP (loc, 1))))
+	{
+	  x = vt_canonicalize_addr (set, XEXP (loc, 0));
+	  if (x != XEXP (loc, 0))
+	    loc = gen_rtx_AND (mode, x, XEXP (loc, 1));
+	  retry = false;
+	}
+
+      if (GET_CODE (loc) == VALUE)
+	{
+	  if (set)
+	    loc = get_addr_from_local_cache (set, loc);
+	  else
+	    loc = get_addr_from_global_cache (loc);
+
+	  /* Consolidate plus_constants.  */
+	  while (ofst && GET_CODE (loc) == PLUS
+		 && GET_CODE (XEXP (loc, 1)) == CONST_INT)
+	    {
+	      ofst += INTVAL (XEXP (loc, 1));
+	      loc = XEXP (loc, 0);
+	    }
+
+	  retry = false;
+	}
+      else
+	{
+	  x = canon_rtx (loc);
+	  if (retry)
+	    retry = (x != loc);
+	  loc = x;
+	}
+    }
+
+  /* Add OFST back in.  */
+  if (ofst)
+    {
+      /* Don't build new RTL if we can help it.  */
+      if (GET_CODE (oloc) == PLUS
+	  && XEXP (oloc, 0) == loc
+	  && INTVAL (XEXP (oloc, 1)) == ofst)
+	return oloc;
+
+      loc = plus_constant (mode, loc, ofst);
+    }
+
+  return loc;
+}
+
+/* Return true iff there's a true dependence between MLOC and LOC.
+   MADDR must be a canonicalized version of MLOC's address.  */
+
+static inline bool
+vt_canon_true_dep (dataflow_set *set, rtx mloc, rtx maddr, rtx loc)
+{
+  if (GET_CODE (loc) != MEM)
+    return false;
+
+  rtx addr = vt_canonicalize_addr (set, XEXP (loc, 0));
+  if (!canon_true_dependence (mloc, GET_MODE (mloc), maddr, loc, addr))
+    return false;
+
+  return true;
+}
+
+/* Hold parameters for the hashtab traversal function
+   drop_overlapping_mem_locs, see below.  */
+
+struct overlapping_mems
+{
+  dataflow_set *set;
+  rtx loc, addr;
+};
+
+/* Remove all MEMs that overlap with COMS->LOC from the location list
+   of a hash table entry for a value.  COMS->ADDR must be a
+   canonicalized form of COMS->LOC's address, and COMS->LOC must be
+   canonicalized itself.  */
+
+int
+drop_overlapping_mem_locs (variable_def **slot, overlapping_mems *coms)
+{
+  dataflow_set *set = coms->set;
+  rtx mloc = coms->loc, addr = coms->addr;
+  variable var = *slot;
+
+  if (var->onepart == ONEPART_VALUE)
+    {
+      location_chain loc, *locp;
+      bool changed = false;
+      rtx cur_loc;
+
+      gcc_assert (var->n_var_parts == 1);
+
+      if (shared_var_p (var, set->vars))
+	{
+	  for (loc = var->var_part[0].loc_chain; loc; loc = loc->next)
+	    if (vt_canon_true_dep (set, mloc, addr, loc->loc))
+	      break;
+
+	  if (!loc)
+	    return 1;
+
+	  slot = unshare_variable (set, slot, var, VAR_INIT_STATUS_UNKNOWN);
+	  var = *slot;
+	  gcc_assert (var->n_var_parts == 1);
+	}
+
+      if (VAR_LOC_1PAUX (var))
+	cur_loc = VAR_LOC_FROM (var);
+      else
+	cur_loc = var->var_part[0].cur_loc;
+
+      for (locp = &var->var_part[0].loc_chain, loc = *locp;
+	   loc; loc = *locp)
+	{
+	  if (!vt_canon_true_dep (set, mloc, addr, loc->loc))
+	    {
+	      locp = &loc->next;
+	      continue;
+	    }
+
+	  *locp = loc->next;
+	  /* If we have deleted the location which was last emitted
+	     we have to emit new location so add the variable to set
+	     of changed variables.  */
+	  if (cur_loc == loc->loc)
+	    {
+	      changed = true;
+	      var->var_part[0].cur_loc = NULL;
+	      if (VAR_LOC_1PAUX (var))
+		VAR_LOC_FROM (var) = NULL;
+	    }
+	  pool_free (loc_chain_pool, loc);
+	}
+
+      if (!var->var_part[0].loc_chain)
+	{
+	  var->n_var_parts--;
+	  changed = true;
+	}
+      if (changed)
+	variable_was_changed (var, set);
+    }
+
+  return 1;
+}
+
+/* Remove from SET all VALUE bindings to MEMs that overlap with LOC.  */
+
+static void
+clobber_overlapping_mems (dataflow_set *set, rtx loc)
+{
+  struct overlapping_mems coms;
+
+  gcc_checking_assert (GET_CODE (loc) == MEM);
+
+  coms.set = set;
+  coms.loc = canon_rtx (loc);
+  coms.addr = vt_canonicalize_addr (set, XEXP (loc, 0));
+
+  set->traversed_vars = set->vars;
+  shared_hash_htab (set->vars)
+    .traverse <overlapping_mems*, drop_overlapping_mem_locs> (&coms);
+  set->traversed_vars = NULL;
+}
+
+/* Set the location of DV, OFFSET as the MEM LOC.  */
+
+static void
+var_mem_decl_set (dataflow_set *set, rtx loc, enum var_init_status initialized,
+		  decl_or_value dv, HOST_WIDE_INT offset, rtx set_src,
+		  enum insert_option iopt)
+{
+  if (dv_is_decl_p (dv))
+    dv = dv_from_decl (var_debug_decl (dv_as_decl (dv)));
+
+  set_variable_part (set, loc, dv, offset, initialized, set_src, iopt);
+}
+
+/* Set the location part of variable MEM_EXPR (LOC) in dataflow set
+   SET to LOC.
+   Adjust the address first if it is stack pointer based.  */
+
+static void
+var_mem_set (dataflow_set *set, rtx loc, enum var_init_status initialized,
+	     rtx set_src)
+{
+  tree decl = MEM_EXPR (loc);
+  HOST_WIDE_INT offset = INT_MEM_OFFSET (loc);
+
+  var_mem_decl_set (set, loc, initialized,
+		    dv_from_decl (decl), offset, set_src, INSERT);
+}
+
+/* Delete and set the location part of variable MEM_EXPR (LOC) in
+   dataflow set SET to LOC.  If MODIFY is true, any other live copies
+   of the same variable part are also deleted from the dataflow set,
+   otherwise the variable part is assumed to be copied from another
+   location holding the same part.
+   Adjust the address first if it is stack pointer based.  */
+
+static void
+var_mem_delete_and_set (dataflow_set *set, rtx loc, bool modify,
+			enum var_init_status initialized, rtx set_src)
+{
+  tree decl = MEM_EXPR (loc);
+  HOST_WIDE_INT offset = INT_MEM_OFFSET (loc);
+
+  clobber_overlapping_mems (set, loc);
+  decl = var_debug_decl (decl);
+
+  if (initialized == VAR_INIT_STATUS_UNKNOWN)
+    initialized = get_init_value (set, loc, dv_from_decl (decl));
+
+  if (modify)
+    clobber_variable_part (set, NULL, dv_from_decl (decl), offset, set_src);
+  var_mem_set (set, loc, initialized, set_src);
+}
+
+/* Delete the location part LOC from dataflow set SET.  If CLOBBER is
+   true, also delete any other live copies of the same variable part.
+   Adjust the address first if it is stack pointer based.  */
+
+static void
+var_mem_delete (dataflow_set *set, rtx loc, bool clobber)
+{
+  tree decl = MEM_EXPR (loc);
+  HOST_WIDE_INT offset = INT_MEM_OFFSET (loc);
+
+  clobber_overlapping_mems (set, loc);
+  decl = var_debug_decl (decl);
+  if (clobber)
+    clobber_variable_part (set, NULL, dv_from_decl (decl), offset, NULL);
+  delete_variable_part (set, loc, dv_from_decl (decl), offset);
+}
+
+/* Return true if LOC should not be expanded for location expressions,
+   or used in them.  */
+
+static inline bool
+unsuitable_loc (rtx loc)
+{
+  switch (GET_CODE (loc))
+    {
+    case PC:
+    case SCRATCH:
+    case CC0:
+    case ASM_INPUT:
+    case ASM_OPERANDS:
+      return true;
+
+    default:
+      return false;
+    }
+}
+
+/* Bind VAL to LOC in SET.  If MODIFIED, detach LOC from any values
+   bound to it.  */
+
+static inline void
+val_bind (dataflow_set *set, rtx val, rtx loc, bool modified)
+{
+  if (REG_P (loc))
+    {
+      if (modified)
+	var_regno_delete (set, REGNO (loc));
+      var_reg_decl_set (set, loc, VAR_INIT_STATUS_INITIALIZED,
+			dv_from_value (val), 0, NULL_RTX, INSERT);
+    }
+  else if (MEM_P (loc))
+    {
+      struct elt_loc_list *l = CSELIB_VAL_PTR (val)->locs;
+
+      if (modified)
+	clobber_overlapping_mems (set, loc);
+
+      if (l && GET_CODE (l->loc) == VALUE)
+	l = canonical_cselib_val (CSELIB_VAL_PTR (l->loc))->locs;
+
+      /* If this MEM is a global constant, we don't need it in the
+	 dynamic tables.  ??? We should test this before emitting the
+	 micro-op in the first place.  */
+      while (l)
+	if (GET_CODE (l->loc) == MEM && XEXP (l->loc, 0) == XEXP (loc, 0))
+	  break;
+	else
+	  l = l->next;
+
+      if (!l)
+	var_mem_decl_set (set, loc, VAR_INIT_STATUS_INITIALIZED,
+			  dv_from_value (val), 0, NULL_RTX, INSERT);
+    }
+  else
+    {
+      /* Other kinds of equivalences are necessarily static, at least
+	 so long as we do not perform substitutions while merging
+	 expressions.  */
+      gcc_unreachable ();
+      set_variable_part (set, loc, dv_from_value (val), 0,
+			 VAR_INIT_STATUS_INITIALIZED, NULL_RTX, INSERT);
+    }
+}
+
+/* Bind a value to a location it was just stored in.  If MODIFIED
+   holds, assume the location was modified, detaching it from any
+   values bound to it.  */
+
+static void
+val_store (dataflow_set *set, rtx val, rtx loc, rtx insn, bool modified)
+{
+  cselib_val *v = CSELIB_VAL_PTR (val);
+
+  gcc_assert (cselib_preserved_value_p (v));
+
+  if (dump_file)
+    {
+      fprintf (dump_file, "%i: ", insn ? INSN_UID (insn) : 0);
+      print_inline_rtx (dump_file, loc, 0);
+      fprintf (dump_file, " evaluates to ");
+      print_inline_rtx (dump_file, val, 0);
+      if (v->locs)
+	{
+	  struct elt_loc_list *l;
+	  for (l = v->locs; l; l = l->next)
+	    {
+	      fprintf (dump_file, "\n%i: ", INSN_UID (l->setting_insn));
+	      print_inline_rtx (dump_file, l->loc, 0);
+	    }
+	}
+      fprintf (dump_file, "\n");
+    }
+
+  gcc_checking_assert (!unsuitable_loc (loc));
+
+  val_bind (set, val, loc, modified);
+}
+
+/* Clear (canonical address) slots that reference X.  */
+
+static bool
+local_get_addr_clear_given_value (const void *v ATTRIBUTE_UNUSED,
+				  void **slot, void *x)
+{
+  if (vt_get_canonicalize_base ((rtx)*slot) == x)
+    *slot = NULL;
+  return true;
+}
+
+/* Reset this node, detaching all its equivalences.  Return the slot
+   in the variable hash table that holds dv, if there is one.  */
+
+static void
+val_reset (dataflow_set *set, decl_or_value dv)
+{
+  variable var = shared_hash_find (set->vars, dv) ;
+  location_chain node;
+  rtx cval;
+
+  if (!var || !var->n_var_parts)
+    return;
+
+  gcc_assert (var->n_var_parts == 1);
+
+  if (var->onepart == ONEPART_VALUE)
+    {
+      rtx x = dv_as_value (dv);
+      void **slot;
+      
+      /* Relationships in the global cache don't change, so reset the
+	 local cache entry only.  */
+      slot = pointer_map_contains (local_get_addr_cache, x);
+      if (slot)
+	{
+	  /* If the value resolved back to itself, odds are that other
+	     values may have cached it too.  These entries now refer
+	     to the old X, so detach them too.  Entries that used the
+	     old X but resolved to something else remain ok as long as
+	     that something else isn't also reset.  */
+	  if (*slot == x)
+	    pointer_map_traverse (local_get_addr_cache,
+				  local_get_addr_clear_given_value, x);
+	  *slot = NULL;
+	}
+    }
+
+  cval = NULL;
+  for (node = var->var_part[0].loc_chain; node; node = node->next)
+    if (GET_CODE (node->loc) == VALUE
+	&& canon_value_cmp (node->loc, cval))
+      cval = node->loc;
+
+  for (node = var->var_part[0].loc_chain; node; node = node->next)
+    if (GET_CODE (node->loc) == VALUE && cval != node->loc)
+      {
+	/* Redirect the equivalence link to the new canonical
+	   value, or simply remove it if it would point at
+	   itself.  */
+	if (cval)
+	  set_variable_part (set, cval, dv_from_value (node->loc),
+			     0, node->init, node->set_src, NO_INSERT);
+	delete_variable_part (set, dv_as_value (dv),
+			      dv_from_value (node->loc), 0);
+      }
+
+  if (cval)
+    {
+      decl_or_value cdv = dv_from_value (cval);
+
+      /* Keep the remaining values connected, accummulating links
+	 in the canonical value.  */
+      for (node = var->var_part[0].loc_chain; node; node = node->next)
+	{
+	  if (node->loc == cval)
+	    continue;
+	  else if (GET_CODE (node->loc) == REG)
+	    var_reg_decl_set (set, node->loc, node->init, cdv, 0,
+			      node->set_src, NO_INSERT);
+	  else if (GET_CODE (node->loc) == MEM)
+	    var_mem_decl_set (set, node->loc, node->init, cdv, 0,
+			      node->set_src, NO_INSERT);
+	  else
+	    set_variable_part (set, node->loc, cdv, 0,
+			       node->init, node->set_src, NO_INSERT);
+	}
+    }
+
+  /* We remove this last, to make sure that the canonical value is not
+     removed to the point of requiring reinsertion.  */
+  if (cval)
+    delete_variable_part (set, dv_as_value (dv), dv_from_value (cval), 0);
+
+  clobber_variable_part (set, NULL, dv, 0, NULL);
+}
+
+/* Find the values in a given location and map the val to another
+   value, if it is unique, or add the location as one holding the
+   value.  */
+
+static void
+val_resolve (dataflow_set *set, rtx val, rtx loc, rtx insn)
+{
+  decl_or_value dv = dv_from_value (val);
+
+  if (dump_file && (dump_flags & TDF_DETAILS))
+    {
+      if (insn)
+	fprintf (dump_file, "%i: ", INSN_UID (insn));
+      else
+	fprintf (dump_file, "head: ");
+      print_inline_rtx (dump_file, val, 0);
+      fputs (" is at ", dump_file);
+      print_inline_rtx (dump_file, loc, 0);
+      fputc ('\n', dump_file);
+    }
+
+  val_reset (set, dv);
+
+  gcc_checking_assert (!unsuitable_loc (loc));
+
+  if (REG_P (loc))
+    {
+      attrs node, found = NULL;
+
+      for (node = set->regs[REGNO (loc)]; node; node = node->next)
+	if (dv_is_value_p (node->dv)
+	    && GET_MODE (dv_as_value (node->dv)) == GET_MODE (loc))
+	  {
+	    found = node;
+
+	    /* Map incoming equivalences.  ??? Wouldn't it be nice if
+	     we just started sharing the location lists?  Maybe a
+	     circular list ending at the value itself or some
+	     such.  */
+	    set_variable_part (set, dv_as_value (node->dv),
+			       dv_from_value (val), node->offset,
+			       VAR_INIT_STATUS_INITIALIZED, NULL_RTX, INSERT);
+	    set_variable_part (set, val, node->dv, node->offset,
+			       VAR_INIT_STATUS_INITIALIZED, NULL_RTX, INSERT);
+	  }
+
+      /* If we didn't find any equivalence, we need to remember that
+	 this value is held in the named register.  */
+      if (found)
+	return;
+    }
+  /* ??? Attempt to find and merge equivalent MEMs or other
+     expressions too.  */
+
+  val_bind (set, val, loc, false);
+}
+
+/* Initialize dataflow set SET to be empty.
+   VARS_SIZE is the initial size of hash table VARS.  */
+
+static void
+dataflow_set_init (dataflow_set *set)
+{
+  init_attrs_list_set (set->regs);
+  set->vars = shared_hash_copy (empty_shared_hash);
+  set->stack_adjust = 0;
+  set->traversed_vars = NULL;
+}
+
+/* Delete the contents of dataflow set SET.  */
+
+static void
+dataflow_set_clear (dataflow_set *set)
+{
+  int i;
+
+  for (i = 0; i < FIRST_PSEUDO_REGISTER; i++)
+    attrs_list_clear (&set->regs[i]);
+
+  shared_hash_destroy (set->vars);
+  set->vars = shared_hash_copy (empty_shared_hash);
+}
+
+/* Copy the contents of dataflow set SRC to DST.  */
+
+static void
+dataflow_set_copy (dataflow_set *dst, dataflow_set *src)
+{
+  int i;
+
+  for (i = 0; i < FIRST_PSEUDO_REGISTER; i++)
+    attrs_list_copy (&dst->regs[i], src->regs[i]);
+
+  shared_hash_destroy (dst->vars);
+  dst->vars = shared_hash_copy (src->vars);
+  dst->stack_adjust = src->stack_adjust;
+}
+
+/* Information for merging lists of locations for a given offset of variable.
+ */
+struct variable_union_info
+{
+  /* Node of the location chain.  */
+  location_chain lc;
+
+  /* The sum of positions in the input chains.  */
+  int pos;
+
+  /* The position in the chain of DST dataflow set.  */
+  int pos_dst;
+};
+
+/* Buffer for location list sorting and its allocated size.  */
+static struct variable_union_info *vui_vec;
+static int vui_allocated;
+
+/* Compare function for qsort, order the structures by POS element.  */
+
+static int
+variable_union_info_cmp_pos (const void *n1, const void *n2)
+{
+  const struct variable_union_info *const i1 =
+    (const struct variable_union_info *) n1;
+  const struct variable_union_info *const i2 =
+    ( const struct variable_union_info *) n2;
+
+  if (i1->pos != i2->pos)
+    return i1->pos - i2->pos;
+
+  return (i1->pos_dst - i2->pos_dst);
+}
+
+/* Compute union of location parts of variable *SLOT and the same variable
+   from hash table DATA.  Compute "sorted" union of the location chains
+   for common offsets, i.e. the locations of a variable part are sorted by
+   a priority where the priority is the sum of the positions in the 2 chains
+   (if a location is only in one list the position in the second list is
+   defined to be larger than the length of the chains).
+   When we are updating the location parts the newest location is in the
+   beginning of the chain, so when we do the described "sorted" union
+   we keep the newest locations in the beginning.  */
+
+static int
+variable_union (variable src, dataflow_set *set)
+{
+  variable dst;
+  variable_def **dstp;
+  int i, j, k;
+
+  dstp = shared_hash_find_slot (set->vars, src->dv);
+  if (!dstp || !*dstp)
+    {
+      src->refcount++;
+
+      dst_can_be_shared = false;
+      if (!dstp)
+	dstp = shared_hash_find_slot_unshare (&set->vars, src->dv, INSERT);
+
+      *dstp = src;
+
+      /* Continue traversing the hash table.  */
+      return 1;
+    }
+  else
+    dst = *dstp;
+
+  gcc_assert (src->n_var_parts);
+  gcc_checking_assert (src->onepart == dst->onepart);
+
+  /* We can combine one-part variables very efficiently, because their
+     entries are in canonical order.  */
+  if (src->onepart)
+    {
+      location_chain *nodep, dnode, snode;
+
+      gcc_assert (src->n_var_parts == 1
+		  && dst->n_var_parts == 1);
+
+      snode = src->var_part[0].loc_chain;
+      gcc_assert (snode);
+
+    restart_onepart_unshared:
+      nodep = &dst->var_part[0].loc_chain;
+      dnode = *nodep;
+      gcc_assert (dnode);
+
+      while (snode)
+	{
+	  int r = dnode ? loc_cmp (dnode->loc, snode->loc) : 1;
+
+	  if (r > 0)
+	    {
+	      location_chain nnode;
+
+	      if (shared_var_p (dst, set->vars))
+		{
+		  dstp = unshare_variable (set, dstp, dst,
+					   VAR_INIT_STATUS_INITIALIZED);
+		  dst = *dstp;
+		  goto restart_onepart_unshared;
+		}
+
+	      *nodep = nnode = (location_chain) pool_alloc (loc_chain_pool);
+	      nnode->loc = snode->loc;
+	      nnode->init = snode->init;
+	      if (!snode->set_src || MEM_P (snode->set_src))
+		nnode->set_src = NULL;
+	      else
+		nnode->set_src = snode->set_src;
+	      nnode->next = dnode;
+	      dnode = nnode;
+	    }
+	  else if (r == 0)
+	    gcc_checking_assert (rtx_equal_p (dnode->loc, snode->loc));
+
+	  if (r >= 0)
+	    snode = snode->next;
+
+	  nodep = &dnode->next;
+	  dnode = *nodep;
+	}
+
+      return 1;
+    }
+
+  gcc_checking_assert (!src->onepart);
+
+  /* Count the number of location parts, result is K.  */
+  for (i = 0, j = 0, k = 0;
+       i < src->n_var_parts && j < dst->n_var_parts; k++)
+    {
+      if (VAR_PART_OFFSET (src, i) == VAR_PART_OFFSET (dst, j))
+	{
+	  i++;
+	  j++;
+	}
+      else if (VAR_PART_OFFSET (src, i) < VAR_PART_OFFSET (dst, j))
+	i++;
+      else
+	j++;
+    }
+  k += src->n_var_parts - i;
+  k += dst->n_var_parts - j;
+
+  /* We track only variables whose size is <= MAX_VAR_PARTS bytes
+     thus there are at most MAX_VAR_PARTS different offsets.  */
+  gcc_checking_assert (dst->onepart ? k == 1 : k <= MAX_VAR_PARTS);
+
+  if (dst->n_var_parts != k && shared_var_p (dst, set->vars))
+    {
+      dstp = unshare_variable (set, dstp, dst, VAR_INIT_STATUS_UNKNOWN);
+      dst = *dstp;
+    }
+
+  i = src->n_var_parts - 1;
+  j = dst->n_var_parts - 1;
+  dst->n_var_parts = k;
+
+  for (k--; k >= 0; k--)
+    {
+      location_chain node, node2;
+
+      if (i >= 0 && j >= 0
+	  && VAR_PART_OFFSET (src, i) == VAR_PART_OFFSET (dst, j))
+	{
+	  /* Compute the "sorted" union of the chains, i.e. the locations which
+	     are in both chains go first, they are sorted by the sum of
+	     positions in the chains.  */
+	  int dst_l, src_l;
+	  int ii, jj, n;
+	  struct variable_union_info *vui;
+
+	  /* If DST is shared compare the location chains.
+	     If they are different we will modify the chain in DST with
+	     high probability so make a copy of DST.  */
+	  if (shared_var_p (dst, set->vars))
+	    {
+	      for (node = src->var_part[i].loc_chain,
+		   node2 = dst->var_part[j].loc_chain; node && node2;
+		   node = node->next, node2 = node2->next)
+		{
+		  if (!((REG_P (node2->loc)
+			 && REG_P (node->loc)
+			 && REGNO (node2->loc) == REGNO (node->loc))
+			|| rtx_equal_p (node2->loc, node->loc)))
+		    {
+		      if (node2->init < node->init)
+		        node2->init = node->init;
+		      break;
+		    }
+		}
+	      if (node || node2)
+		{
+		  dstp = unshare_variable (set, dstp, dst,
+					   VAR_INIT_STATUS_UNKNOWN);
+		  dst = (variable)*dstp;
+		}
+	    }
+
+	  src_l = 0;
+	  for (node = src->var_part[i].loc_chain; node; node = node->next)
+	    src_l++;
+	  dst_l = 0;
+	  for (node = dst->var_part[j].loc_chain; node; node = node->next)
+	    dst_l++;
+
+	  if (dst_l == 1)
+	    {
+	      /* The most common case, much simpler, no qsort is needed.  */
+	      location_chain dstnode = dst->var_part[j].loc_chain;
+	      dst->var_part[k].loc_chain = dstnode;
+	      VAR_PART_OFFSET (dst, k) = VAR_PART_OFFSET (dst, j);
+	      node2 = dstnode;
+	      for (node = src->var_part[i].loc_chain; node; node = node->next)
+		if (!((REG_P (dstnode->loc)
+		       && REG_P (node->loc)
+		       && REGNO (dstnode->loc) == REGNO (node->loc))
+		      || rtx_equal_p (dstnode->loc, node->loc)))
+		  {
+		    location_chain new_node;
+
+		    /* Copy the location from SRC.  */
+		    new_node = (location_chain) pool_alloc (loc_chain_pool);
+		    new_node->loc = node->loc;
+		    new_node->init = node->init;
+		    if (!node->set_src || MEM_P (node->set_src))
+		      new_node->set_src = NULL;
+		    else
+		      new_node->set_src = node->set_src;
+		    node2->next = new_node;
+		    node2 = new_node;
+		  }
+	      node2->next = NULL;
+	    }
+	  else
+	    {
+	      if (src_l + dst_l > vui_allocated)
+		{
+		  vui_allocated = MAX (vui_allocated * 2, src_l + dst_l);
+		  vui_vec = XRESIZEVEC (struct variable_union_info, vui_vec,
+					vui_allocated);
+		}
+	      vui = vui_vec;
+
+	      /* Fill in the locations from DST.  */
+	      for (node = dst->var_part[j].loc_chain, jj = 0; node;
+		   node = node->next, jj++)
+		{
+		  vui[jj].lc = node;
+		  vui[jj].pos_dst = jj;
+
+		  /* Pos plus value larger than a sum of 2 valid positions.  */
+		  vui[jj].pos = jj + src_l + dst_l;
+		}
+
+	      /* Fill in the locations from SRC.  */
+	      n = dst_l;
+	      for (node = src->var_part[i].loc_chain, ii = 0; node;
+		   node = node->next, ii++)
+		{
+		  /* Find location from NODE.  */
+		  for (jj = 0; jj < dst_l; jj++)
+		    {
+		      if ((REG_P (vui[jj].lc->loc)
+			   && REG_P (node->loc)
+			   && REGNO (vui[jj].lc->loc) == REGNO (node->loc))
+			  || rtx_equal_p (vui[jj].lc->loc, node->loc))
+			{
+			  vui[jj].pos = jj + ii;
+			  break;
+			}
+		    }
+		  if (jj >= dst_l)	/* The location has not been found.  */
+		    {
+		      location_chain new_node;
+
+		      /* Copy the location from SRC.  */
+		      new_node = (location_chain) pool_alloc (loc_chain_pool);
+		      new_node->loc = node->loc;
+		      new_node->init = node->init;
+		      if (!node->set_src || MEM_P (node->set_src))
+			new_node->set_src = NULL;
+		      else
+			new_node->set_src = node->set_src;
+		      vui[n].lc = new_node;
+		      vui[n].pos_dst = src_l + dst_l;
+		      vui[n].pos = ii + src_l + dst_l;
+		      n++;
+		    }
+		}
+
+	      if (dst_l == 2)
+		{
+		  /* Special case still very common case.  For dst_l == 2
+		     all entries dst_l ... n-1 are sorted, with for i >= dst_l
+		     vui[i].pos == i + src_l + dst_l.  */
+		  if (vui[0].pos > vui[1].pos)
+		    {
+		      /* Order should be 1, 0, 2... */
+		      dst->var_part[k].loc_chain = vui[1].lc;
+		      vui[1].lc->next = vui[0].lc;
+		      if (n >= 3)
+			{
+			  vui[0].lc->next = vui[2].lc;
+			  vui[n - 1].lc->next = NULL;
+			}
+		      else
+			vui[0].lc->next = NULL;
+		      ii = 3;
+		    }
+		  else
+		    {
+		      dst->var_part[k].loc_chain = vui[0].lc;
+		      if (n >= 3 && vui[2].pos < vui[1].pos)
+			{
+			  /* Order should be 0, 2, 1, 3... */
+			  vui[0].lc->next = vui[2].lc;
+			  vui[2].lc->next = vui[1].lc;
+			  if (n >= 4)
+			    {
+			      vui[1].lc->next = vui[3].lc;
+			      vui[n - 1].lc->next = NULL;
+			    }
+			  else
+			    vui[1].lc->next = NULL;
+			  ii = 4;
+			}
+		      else
+			{
+			  /* Order should be 0, 1, 2... */
+			  ii = 1;
+			  vui[n - 1].lc->next = NULL;
+			}
+		    }
+		  for (; ii < n; ii++)
+		    vui[ii - 1].lc->next = vui[ii].lc;
+		}
+	      else
+		{
+		  qsort (vui, n, sizeof (struct variable_union_info),
+			 variable_union_info_cmp_pos);
+
+		  /* Reconnect the nodes in sorted order.  */
+		  for (ii = 1; ii < n; ii++)
+		    vui[ii - 1].lc->next = vui[ii].lc;
+		  vui[n - 1].lc->next = NULL;
+		  dst->var_part[k].loc_chain = vui[0].lc;
+		}
+
+	      VAR_PART_OFFSET (dst, k) = VAR_PART_OFFSET (dst, j);
+	    }
+	  i--;
+	  j--;
+	}
+      else if ((i >= 0 && j >= 0
+		&& VAR_PART_OFFSET (src, i) < VAR_PART_OFFSET (dst, j))
+	       || i < 0)
+	{
+	  dst->var_part[k] = dst->var_part[j];
+	  j--;
+	}
+      else if ((i >= 0 && j >= 0
+		&& VAR_PART_OFFSET (src, i) > VAR_PART_OFFSET (dst, j))
+	       || j < 0)
+	{
+	  location_chain *nextp;
+
+	  /* Copy the chain from SRC.  */
+	  nextp = &dst->var_part[k].loc_chain;
+	  for (node = src->var_part[i].loc_chain; node; node = node->next)
+	    {
+	      location_chain new_lc;
+
+	      new_lc = (location_chain) pool_alloc (loc_chain_pool);
+	      new_lc->next = NULL;
+	      new_lc->init = node->init;
+	      if (!node->set_src || MEM_P (node->set_src))
+		new_lc->set_src = NULL;
+	      else
+		new_lc->set_src = node->set_src;
+	      new_lc->loc = node->loc;
+
+	      *nextp = new_lc;
+	      nextp = &new_lc->next;
+	    }
+
+	  VAR_PART_OFFSET (dst, k) = VAR_PART_OFFSET (src, i);
+	  i--;
+	}
+      dst->var_part[k].cur_loc = NULL;
+    }
+
+  if (flag_var_tracking_uninit)
+    for (i = 0; i < src->n_var_parts && i < dst->n_var_parts; i++)
+      {
+	location_chain node, node2;
+	for (node = src->var_part[i].loc_chain; node; node = node->next)
+	  for (node2 = dst->var_part[i].loc_chain; node2; node2 = node2->next)
+	    if (rtx_equal_p (node->loc, node2->loc))
+	      {
+		if (node->init > node2->init)
+		  node2->init = node->init;
+	      }
+      }
+
+  /* Continue traversing the hash table.  */
+  return 1;
+}
+
+/* Compute union of dataflow sets SRC and DST and store it to DST.  */
+
+static void
+dataflow_set_union (dataflow_set *dst, dataflow_set *src)
+{
+  int i;
+
+  for (i = 0; i < FIRST_PSEUDO_REGISTER; i++)
+    attrs_list_union (&dst->regs[i], src->regs[i]);
+
+  if (dst->vars == empty_shared_hash)
+    {
+      shared_hash_destroy (dst->vars);
+      dst->vars = shared_hash_copy (src->vars);
+    }
+  else
+    {
+      variable_iterator_type hi;
+      variable var;
+
+      FOR_EACH_HASH_TABLE_ELEMENT (shared_hash_htab (src->vars),
+				   var, variable, hi)
+	variable_union (var, dst);
+    }
+}
+
+/* Whether the value is currently being expanded.  */
+#define VALUE_RECURSED_INTO(x) \
+  (RTL_FLAG_CHECK2 ("VALUE_RECURSED_INTO", (x), VALUE, DEBUG_EXPR)->used)
+
+/* Whether no expansion was found, saving useless lookups.
+   It must only be set when VALUE_CHANGED is clear.  */
+#define NO_LOC_P(x) \
+  (RTL_FLAG_CHECK2 ("NO_LOC_P", (x), VALUE, DEBUG_EXPR)->return_val)
+
+/* Whether cur_loc in the value needs to be (re)computed.  */
+#define VALUE_CHANGED(x) \
+  (RTL_FLAG_CHECK1 ("VALUE_CHANGED", (x), VALUE)->frame_related)
+/* Whether cur_loc in the decl needs to be (re)computed.  */
+#define DECL_CHANGED(x) TREE_VISITED (x)
+
+/* Record (if NEWV) that DV needs to have its cur_loc recomputed.  For
+   user DECLs, this means they're in changed_variables.  Values and
+   debug exprs may be left with this flag set if no user variable
+   requires them to be evaluated.  */
+
+static inline void
+set_dv_changed (decl_or_value dv, bool newv)
+{
+  switch (dv_onepart_p (dv))
+    {
+    case ONEPART_VALUE:
+      if (newv)
+	NO_LOC_P (dv_as_value (dv)) = false;
+      VALUE_CHANGED (dv_as_value (dv)) = newv;
+      break;
+
+    case ONEPART_DEXPR:
+      if (newv)
+	NO_LOC_P (DECL_RTL_KNOWN_SET (dv_as_decl (dv))) = false;
+      /* Fall through...  */
+
+    default:
+      DECL_CHANGED (dv_as_decl (dv)) = newv;
+      break;
+    }
+}
+
+/* Return true if DV needs to have its cur_loc recomputed.  */
+
+static inline bool
+dv_changed_p (decl_or_value dv)
+{
+  return (dv_is_value_p (dv)
+	  ? VALUE_CHANGED (dv_as_value (dv))
+	  : DECL_CHANGED (dv_as_decl (dv)));
+}
+
+/* Return a location list node whose loc is rtx_equal to LOC, in the
+   location list of a one-part variable or value VAR, or in that of
+   any values recursively mentioned in the location lists.  VARS must
+   be in star-canonical form.  */
+
+static location_chain
+find_loc_in_1pdv (rtx loc, variable var, variable_table_type vars)
+{
+  location_chain node;
+  enum rtx_code loc_code;
+
+  if (!var)
+    return NULL;
+
+  gcc_checking_assert (var->onepart);
+
+  if (!var->n_var_parts)
+    return NULL;
+
+  gcc_checking_assert (loc != dv_as_opaque (var->dv));
+
+  loc_code = GET_CODE (loc);
+  for (node = var->var_part[0].loc_chain; node; node = node->next)
+    {
+      decl_or_value dv;
+      variable rvar;
+
+      if (GET_CODE (node->loc) != loc_code)
+	{
+	  if (GET_CODE (node->loc) != VALUE)
+	    continue;
+	}
+      else if (loc == node->loc)
+	return node;
+      else if (loc_code != VALUE)
+	{
+	  if (rtx_equal_p (loc, node->loc))
+	    return node;
+	  continue;
+	}
+
+      /* Since we're in star-canonical form, we don't need to visit
+	 non-canonical nodes: one-part variables and non-canonical
+	 values would only point back to the canonical node.  */
+      if (dv_is_value_p (var->dv)
+	  && !canon_value_cmp (node->loc, dv_as_value (var->dv)))
+	{
+	  /* Skip all subsequent VALUEs.  */
+	  while (node->next && GET_CODE (node->next->loc) == VALUE)
+	    {
+	      node = node->next;
+	      gcc_checking_assert (!canon_value_cmp (node->loc,
+						     dv_as_value (var->dv)));
+	      if (loc == node->loc)
+		return node;
+	    }
+	  continue;
+	}
+
+      gcc_checking_assert (node == var->var_part[0].loc_chain);
+      gcc_checking_assert (!node->next);
+
+      dv = dv_from_value (node->loc);
+      rvar = vars.find_with_hash (dv, dv_htab_hash (dv));
+      return find_loc_in_1pdv (loc, rvar, vars);
+    }
+
+  /* ??? Gotta look in cselib_val locations too.  */
+
+  return NULL;
+}
+
+/* Hash table iteration argument passed to variable_merge.  */
+struct dfset_merge
+{
+  /* The set in which the merge is to be inserted.  */
+  dataflow_set *dst;
+  /* The set that we're iterating in.  */
+  dataflow_set *cur;
+  /* The set that may contain the other dv we are to merge with.  */
+  dataflow_set *src;
+  /* Number of onepart dvs in src.  */
+  int src_onepart_cnt;
+};
+
+/* Insert LOC in *DNODE, if it's not there yet.  The list must be in
+   loc_cmp order, and it is maintained as such.  */
+
+static void
+insert_into_intersection (location_chain *nodep, rtx loc,
+			  enum var_init_status status)
+{
+  location_chain node;
+  int r;
+
+  for (node = *nodep; node; nodep = &node->next, node = *nodep)
+    if ((r = loc_cmp (node->loc, loc)) == 0)
+      {
+	node->init = MIN (node->init, status);
+	return;
+      }
+    else if (r > 0)
+      break;
+
+  node = (location_chain) pool_alloc (loc_chain_pool);
+
+  node->loc = loc;
+  node->set_src = NULL;
+  node->init = status;
+  node->next = *nodep;
+  *nodep = node;
+}
+
+/* Insert in DEST the intersection of the locations present in both
+   S1NODE and S2VAR, directly or indirectly.  S1NODE is from a
+   variable in DSM->cur, whereas S2VAR is from DSM->src.  dvar is in
+   DSM->dst.  */
+
+static void
+intersect_loc_chains (rtx val, location_chain *dest, struct dfset_merge *dsm,
+		      location_chain s1node, variable s2var)
+{
+  dataflow_set *s1set = dsm->cur;
+  dataflow_set *s2set = dsm->src;
+  location_chain found;
+
+  if (s2var)
+    {
+      location_chain s2node;
+
+      gcc_checking_assert (s2var->onepart);
+
+      if (s2var->n_var_parts)
+	{
+	  s2node = s2var->var_part[0].loc_chain;
+
+	  for (; s1node && s2node;
+	       s1node = s1node->next, s2node = s2node->next)
+	    if (s1node->loc != s2node->loc)
+	      break;
+	    else if (s1node->loc == val)
+	      continue;
+	    else
+	      insert_into_intersection (dest, s1node->loc,
+					MIN (s1node->init, s2node->init));
+	}
+    }
+
+  for (; s1node; s1node = s1node->next)
+    {
+      if (s1node->loc == val)
+	continue;
+
+      if ((found = find_loc_in_1pdv (s1node->loc, s2var,
+				     shared_hash_htab (s2set->vars))))
+	{
+	  insert_into_intersection (dest, s1node->loc,
+				    MIN (s1node->init, found->init));
+	  continue;
+	}
+
+      if (GET_CODE (s1node->loc) == VALUE
+	  && !VALUE_RECURSED_INTO (s1node->loc))
+	{
+	  decl_or_value dv = dv_from_value (s1node->loc);
+	  variable svar = shared_hash_find (s1set->vars, dv);
+	  if (svar)
+	    {
+	      if (svar->n_var_parts == 1)
+		{
+		  VALUE_RECURSED_INTO (s1node->loc) = true;
+		  intersect_loc_chains (val, dest, dsm,
+					svar->var_part[0].loc_chain,
+					s2var);
+		  VALUE_RECURSED_INTO (s1node->loc) = false;
+		}
+	    }
+	}
+
+      /* ??? gotta look in cselib_val locations too.  */
+
+      /* ??? if the location is equivalent to any location in src,
+	 searched recursively
+
+	   add to dst the values needed to represent the equivalence
+
+     telling whether locations S is equivalent to another dv's
+     location list:
+
+       for each location D in the list
+
+         if S and D satisfy rtx_equal_p, then it is present
+
+	 else if D is a value, recurse without cycles
+
+	 else if S and D have the same CODE and MODE
+
+	   for each operand oS and the corresponding oD
+
+	     if oS and oD are not equivalent, then S an D are not equivalent
+
+	     else if they are RTX vectors
+
+	       if any vector oS element is not equivalent to its respective oD,
+	       then S and D are not equivalent
+
+   */
+
+
+    }
+}
+
+/* Return -1 if X should be before Y in a location list for a 1-part
+   variable, 1 if Y should be before X, and 0 if they're equivalent
+   and should not appear in the list.  */
+
+static int
+loc_cmp (rtx x, rtx y)
+{
+  int i, j, r;
+  RTX_CODE code = GET_CODE (x);
+  const char *fmt;
+
+  if (x == y)
+    return 0;
+
+  if (REG_P (x))
+    {
+      if (!REG_P (y))
+	return -1;
+      gcc_assert (GET_MODE (x) == GET_MODE (y));
+      if (REGNO (x) == REGNO (y))
+	return 0;
+      else if (REGNO (x) < REGNO (y))
+	return -1;
+      else
+	return 1;
+    }
+
+  if (REG_P (y))
+    return 1;
+
+  if (MEM_P (x))
+    {
+      if (!MEM_P (y))
+	return -1;
+      gcc_assert (GET_MODE (x) == GET_MODE (y));
+      return loc_cmp (XEXP (x, 0), XEXP (y, 0));
+    }
+
+  if (MEM_P (y))
+    return 1;
+
+  if (GET_CODE (x) == VALUE)
+    {
+      if (GET_CODE (y) != VALUE)
+	return -1;
+      /* Don't assert the modes are the same, that is true only
+	 when not recursing.  (subreg:QI (value:SI 1:1) 0)
+	 and (subreg:QI (value:DI 2:2) 0) can be compared,
+	 even when the modes are different.  */
+      if (canon_value_cmp (x, y))
+	return -1;
+      else
+	return 1;
+    }
+
+  if (GET_CODE (y) == VALUE)
+    return 1;
+
+  /* Entry value is the least preferable kind of expression.  */
+  if (GET_CODE (x) == ENTRY_VALUE)
+    {
+      if (GET_CODE (y) != ENTRY_VALUE)
+	return 1;
+      gcc_assert (GET_MODE (x) == GET_MODE (y));
+      return loc_cmp (ENTRY_VALUE_EXP (x), ENTRY_VALUE_EXP (y));
+    }
+
+  if (GET_CODE (y) == ENTRY_VALUE)
+    return -1;
+
+  if (GET_CODE (x) == GET_CODE (y))
+    /* Compare operands below.  */;
+  else if (GET_CODE (x) < GET_CODE (y))
+    return -1;
+  else
+    return 1;
+
+  gcc_assert (GET_MODE (x) == GET_MODE (y));
+
+  if (GET_CODE (x) == DEBUG_EXPR)
+    {
+      if (DEBUG_TEMP_UID (DEBUG_EXPR_TREE_DECL (x))
+	  < DEBUG_TEMP_UID (DEBUG_EXPR_TREE_DECL (y)))
+	return -1;
+      gcc_checking_assert (DEBUG_TEMP_UID (DEBUG_EXPR_TREE_DECL (x))
+			   > DEBUG_TEMP_UID (DEBUG_EXPR_TREE_DECL (y)));
+      return 1;
+    }
+
+  fmt = GET_RTX_FORMAT (code);
+  for (i = 0; i < GET_RTX_LENGTH (code); i++)
+    switch (fmt[i])
+      {
+      case 'w':
+	if (XWINT (x, i) == XWINT (y, i))
+	  break;
+	else if (XWINT (x, i) < XWINT (y, i))
+	  return -1;
+	else
+	  return 1;
+
+      case 'n':
+      case 'i':
+	if (XINT (x, i) == XINT (y, i))
+	  break;
+	else if (XINT (x, i) < XINT (y, i))
+	  return -1;
+	else
+	  return 1;
+
+      case 'V':
+      case 'E':
+	/* Compare the vector length first.  */
+	if (XVECLEN (x, i) == XVECLEN (y, i))
+	  /* Compare the vectors elements.  */;
+	else if (XVECLEN (x, i) < XVECLEN (y, i))
+	  return -1;
+	else
+	  return 1;
+
+	for (j = 0; j < XVECLEN (x, i); j++)
+	  if ((r = loc_cmp (XVECEXP (x, i, j),
+			    XVECEXP (y, i, j))))
+	    return r;
+	break;
+
+      case 'e':
+	if ((r = loc_cmp (XEXP (x, i), XEXP (y, i))))
+	  return r;
+	break;
+
+      case 'S':
+      case 's':
+	if (XSTR (x, i) == XSTR (y, i))
+	  break;
+	if (!XSTR (x, i))
+	  return -1;
+	if (!XSTR (y, i))
+	  return 1;
+	if ((r = strcmp (XSTR (x, i), XSTR (y, i))) == 0)
+	  break;
+	else if (r < 0)
+	  return -1;
+	else
+	  return 1;
+
+      case 'u':
+	/* These are just backpointers, so they don't matter.  */
+	break;
+
+      case '0':
+      case 't':
+	break;
+
+	/* It is believed that rtx's at this level will never
+	   contain anything but integers and other rtx's,
+	   except for within LABEL_REFs and SYMBOL_REFs.  */
+      default:
+	gcc_unreachable ();
+      }
+
+  return 0;
+}
+
+#if ENABLE_CHECKING
+/* Check the order of entries in one-part variables.   */
+
+int
+canonicalize_loc_order_check (variable_def **slot,
+			      dataflow_set *data ATTRIBUTE_UNUSED)
+{
+  variable var = *slot;
+  location_chain node, next;
+
+#ifdef ENABLE_RTL_CHECKING
+  int i;
+  for (i = 0; i < var->n_var_parts; i++)
+    gcc_assert (var->var_part[0].cur_loc == NULL);
+  gcc_assert (!var->in_changed_variables);
+#endif
+
+  if (!var->onepart)
+    return 1;
+
+  gcc_assert (var->n_var_parts == 1);
+  node = var->var_part[0].loc_chain;
+  gcc_assert (node);
+
+  while ((next = node->next))
+    {
+      gcc_assert (loc_cmp (node->loc, next->loc) < 0);
+      node = next;
+    }
+
+  return 1;
+}
+#endif
+
+/* Mark with VALUE_RECURSED_INTO values that have neighbors that are
+   more likely to be chosen as canonical for an equivalence set.
+   Ensure less likely values can reach more likely neighbors, making
+   the connections bidirectional.  */
+
+int
+canonicalize_values_mark (variable_def **slot, dataflow_set *set)
+{
+  variable var = *slot;
+  decl_or_value dv = var->dv;
+  rtx val;
+  location_chain node;
+
+  if (!dv_is_value_p (dv))
+    return 1;
+
+  gcc_checking_assert (var->n_var_parts == 1);
+
+  val = dv_as_value (dv);
+
+  for (node = var->var_part[0].loc_chain; node; node = node->next)
+    if (GET_CODE (node->loc) == VALUE)
+      {
+	if (canon_value_cmp (node->loc, val))
+	  VALUE_RECURSED_INTO (val) = true;
+	else
+	  {
+	    decl_or_value odv = dv_from_value (node->loc);
+	    variable_def **oslot;
+	    oslot = shared_hash_find_slot_noinsert (set->vars, odv);
+
+	    set_slot_part (set, val, oslot, odv, 0,
+			   node->init, NULL_RTX);
+
+	    VALUE_RECURSED_INTO (node->loc) = true;
+	  }
+      }
+
+  return 1;
+}
+
+/* Remove redundant entries from equivalence lists in onepart
+   variables, canonicalizing equivalence sets into star shapes.  */
+
+int
+canonicalize_values_star (variable_def **slot, dataflow_set *set)
+{
+  variable var = *slot;
+  decl_or_value dv = var->dv;
+  location_chain node;
+  decl_or_value cdv;
+  rtx val, cval;
+  variable_def **cslot;
+  bool has_value;
+  bool has_marks;
+
+  if (!var->onepart)
+    return 1;
+
+  gcc_checking_assert (var->n_var_parts == 1);
+
+  if (dv_is_value_p (dv))
+    {
+      cval = dv_as_value (dv);
+      if (!VALUE_RECURSED_INTO (cval))
+	return 1;
+      VALUE_RECURSED_INTO (cval) = false;
+    }
+  else
+    cval = NULL_RTX;
+
+ restart:
+  val = cval;
+  has_value = false;
+  has_marks = false;
+
+  gcc_assert (var->n_var_parts == 1);
+
+  for (node = var->var_part[0].loc_chain; node; node = node->next)
+    if (GET_CODE (node->loc) == VALUE)
+      {
+	has_value = true;
+	if (VALUE_RECURSED_INTO (node->loc))
+	  has_marks = true;
+	if (canon_value_cmp (node->loc, cval))
+	  cval = node->loc;
+      }
+
+  if (!has_value)
+    return 1;
+
+  if (cval == val)
+    {
+      if (!has_marks || dv_is_decl_p (dv))
+	return 1;
+
+      /* Keep it marked so that we revisit it, either after visiting a
+	 child node, or after visiting a new parent that might be
+	 found out.  */
+      VALUE_RECURSED_INTO (val) = true;
+
+      for (node = var->var_part[0].loc_chain; node; node = node->next)
+	if (GET_CODE (node->loc) == VALUE
+	    && VALUE_RECURSED_INTO (node->loc))
+	  {
+	    cval = node->loc;
+	  restart_with_cval:
+	    VALUE_RECURSED_INTO (cval) = false;
+	    dv = dv_from_value (cval);
+	    slot = shared_hash_find_slot_noinsert (set->vars, dv);
+	    if (!slot)
+	      {
+		gcc_assert (dv_is_decl_p (var->dv));
+		/* The canonical value was reset and dropped.
+		   Remove it.  */
+		clobber_variable_part (set, NULL, var->dv, 0, NULL);
+		return 1;
+	      }
+	    var = *slot;
+	    gcc_assert (dv_is_value_p (var->dv));
+	    if (var->n_var_parts == 0)
+	      return 1;
+	    gcc_assert (var->n_var_parts == 1);
+	    goto restart;
+	  }
+
+      VALUE_RECURSED_INTO (val) = false;
+
+      return 1;
+    }
+
+  /* Push values to the canonical one.  */
+  cdv = dv_from_value (cval);
+  cslot = shared_hash_find_slot_noinsert (set->vars, cdv);
+
+  for (node = var->var_part[0].loc_chain; node; node = node->next)
+    if (node->loc != cval)
+      {
+	cslot = set_slot_part (set, node->loc, cslot, cdv, 0,
+			       node->init, NULL_RTX);
+	if (GET_CODE (node->loc) == VALUE)
+	  {
+	    decl_or_value ndv = dv_from_value (node->loc);
+
+	    set_variable_part (set, cval, ndv, 0, node->init, NULL_RTX,
+			       NO_INSERT);
+
+	    if (canon_value_cmp (node->loc, val))
+	      {
+		/* If it could have been a local minimum, it's not any more,
+		   since it's now neighbor to cval, so it may have to push
+		   to it.  Conversely, if it wouldn't have prevailed over
+		   val, then whatever mark it has is fine: if it was to
+		   push, it will now push to a more canonical node, but if
+		   it wasn't, then it has already pushed any values it might
+		   have to.  */
+		VALUE_RECURSED_INTO (node->loc) = true;
+		/* Make sure we visit node->loc by ensuring we cval is
+		   visited too.  */
+		VALUE_RECURSED_INTO (cval) = true;
+	      }
+	    else if (!VALUE_RECURSED_INTO (node->loc))
+	      /* If we have no need to "recurse" into this node, it's
+		 already "canonicalized", so drop the link to the old
+		 parent.  */
+	      clobber_variable_part (set, cval, ndv, 0, NULL);
+	  }
+	else if (GET_CODE (node->loc) == REG)
+	  {
+	    attrs list = set->regs[REGNO (node->loc)], *listp;
+
+	    /* Change an existing attribute referring to dv so that it
+	       refers to cdv, removing any duplicate this might
+	       introduce, and checking that no previous duplicates
+	       existed, all in a single pass.  */
+
+	    while (list)
+	      {
+		if (list->offset == 0
+		    && (dv_as_opaque (list->dv) == dv_as_opaque (dv)
+			|| dv_as_opaque (list->dv) == dv_as_opaque (cdv)))
+		  break;
+
+		list = list->next;
+	      }
+
+	    gcc_assert (list);
+	    if (dv_as_opaque (list->dv) == dv_as_opaque (dv))
+	      {
+		list->dv = cdv;
+		for (listp = &list->next; (list = *listp); listp = &list->next)
+		  {
+		    if (list->offset)
+		      continue;
+
+		    if (dv_as_opaque (list->dv) == dv_as_opaque (cdv))
+		      {
+			*listp = list->next;
+			pool_free (attrs_pool, list);
+			list = *listp;
+			break;
+		      }
+
+		    gcc_assert (dv_as_opaque (list->dv) != dv_as_opaque (dv));
+		  }
+	      }
+	    else if (dv_as_opaque (list->dv) == dv_as_opaque (cdv))
+	      {
+		for (listp = &list->next; (list = *listp); listp = &list->next)
+		  {
+		    if (list->offset)
+		      continue;
+
+		    if (dv_as_opaque (list->dv) == dv_as_opaque (dv))
+		      {
+			*listp = list->next;
+			pool_free (attrs_pool, list);
+			list = *listp;
+			break;
+		      }
+
+		    gcc_assert (dv_as_opaque (list->dv) != dv_as_opaque (cdv));
+		  }
+	      }
+	    else
+	      gcc_unreachable ();
+
+#if ENABLE_CHECKING
+	    while (list)
+	      {
+		if (list->offset == 0
+		    && (dv_as_opaque (list->dv) == dv_as_opaque (dv)
+			|| dv_as_opaque (list->dv) == dv_as_opaque (cdv)))
+		  gcc_unreachable ();
+
+		list = list->next;
+	      }
+#endif
+	  }
+      }
+
+  if (val)
+    set_slot_part (set, val, cslot, cdv, 0,
+		   VAR_INIT_STATUS_INITIALIZED, NULL_RTX);
+
+  slot = clobber_slot_part (set, cval, slot, 0, NULL);
+
+  /* Variable may have been unshared.  */
+  var = *slot;
+  gcc_checking_assert (var->n_var_parts && var->var_part[0].loc_chain->loc == cval
+		       && var->var_part[0].loc_chain->next == NULL);
+
+  if (VALUE_RECURSED_INTO (cval))
+    goto restart_with_cval;
+
+  return 1;
+}
+
+/* Bind one-part variables to the canonical value in an equivalence
+   set.  Not doing this causes dataflow convergence failure in rare
+   circumstances, see PR42873.  Unfortunately we can't do this
+   efficiently as part of canonicalize_values_star, since we may not
+   have determined or even seen the canonical value of a set when we
+   get to a variable that references another member of the set.  */
+
+int
+canonicalize_vars_star (variable_def **slot, dataflow_set *set)
+{
+  variable var = *slot;
+  decl_or_value dv = var->dv;
+  location_chain node;
+  rtx cval;
+  decl_or_value cdv;
+  variable_def **cslot;
+  variable cvar;
+  location_chain cnode;
+
+  if (!var->onepart || var->onepart == ONEPART_VALUE)
+    return 1;
+
+  gcc_assert (var->n_var_parts == 1);
+
+  node = var->var_part[0].loc_chain;
+
+  if (GET_CODE (node->loc) != VALUE)
+    return 1;
+
+  gcc_assert (!node->next);
+  cval = node->loc;
+
+  /* Push values to the canonical one.  */
+  cdv = dv_from_value (cval);
+  cslot = shared_hash_find_slot_noinsert (set->vars, cdv);
+  if (!cslot)
+    return 1;
+  cvar = *cslot;
+  gcc_assert (cvar->n_var_parts == 1);
+
+  cnode = cvar->var_part[0].loc_chain;
+
+  /* CVAL is canonical if its value list contains non-VALUEs or VALUEs
+     that are not “more canonical” than it.  */
+  if (GET_CODE (cnode->loc) != VALUE
+      || !canon_value_cmp (cnode->loc, cval))
+    return 1;
+
+  /* CVAL was found to be non-canonical.  Change the variable to point
+     to the canonical VALUE.  */
+  gcc_assert (!cnode->next);
+  cval = cnode->loc;
+
+  slot = set_slot_part (set, cval, slot, dv, 0,
+			node->init, node->set_src);
+  clobber_slot_part (set, cval, slot, 0, node->set_src);
+
+  return 1;
+}
+
+/* Combine variable or value in *S1SLOT (in DSM->cur) with the
+   corresponding entry in DSM->src.  Multi-part variables are combined
+   with variable_union, whereas onepart dvs are combined with
+   intersection.  */
+
+static int
+variable_merge_over_cur (variable s1var, struct dfset_merge *dsm)
+{
+  dataflow_set *dst = dsm->dst;
+  variable_def **dstslot;
+  variable s2var, dvar = NULL;
+  decl_or_value dv = s1var->dv;
+  onepart_enum_t onepart = s1var->onepart;
+  rtx val;
+  hashval_t dvhash;
+  location_chain node, *nodep;
+
+  /* If the incoming onepart variable has an empty location list, then
+     the intersection will be just as empty.  For other variables,
+     it's always union.  */
+  gcc_checking_assert (s1var->n_var_parts
+		       && s1var->var_part[0].loc_chain);
+
+  if (!onepart)
+    return variable_union (s1var, dst);
+
+  gcc_checking_assert (s1var->n_var_parts == 1);
+
+  dvhash = dv_htab_hash (dv);
+  if (dv_is_value_p (dv))
+    val = dv_as_value (dv);
+  else
+    val = NULL;
+
+  s2var = shared_hash_find_1 (dsm->src->vars, dv, dvhash);
+  if (!s2var)
+    {
+      dst_can_be_shared = false;
+      return 1;
+    }
+
+  dsm->src_onepart_cnt--;
+  gcc_assert (s2var->var_part[0].loc_chain
+	      && s2var->onepart == onepart
+	      && s2var->n_var_parts == 1);
+
+  dstslot = shared_hash_find_slot_noinsert_1 (dst->vars, dv, dvhash);
+  if (dstslot)
+    {
+      dvar = *dstslot;
+      gcc_assert (dvar->refcount == 1
+		  && dvar->onepart == onepart
+		  && dvar->n_var_parts == 1);
+      nodep = &dvar->var_part[0].loc_chain;
+    }
+  else
+    {
+      nodep = &node;
+      node = NULL;
+    }
+
+  if (!dstslot && !onepart_variable_different_p (s1var, s2var))
+    {
+      dstslot = shared_hash_find_slot_unshare_1 (&dst->vars, dv,
+						 dvhash, INSERT);
+      *dstslot = dvar = s2var;
+      dvar->refcount++;
+    }
+  else
+    {
+      dst_can_be_shared = false;
+
+      intersect_loc_chains (val, nodep, dsm,
+			    s1var->var_part[0].loc_chain, s2var);
+
+      if (!dstslot)
+	{
+	  if (node)
+	    {
+	      dvar = (variable) pool_alloc (onepart_pool (onepart));
+	      dvar->dv = dv;
+	      dvar->refcount = 1;
+	      dvar->n_var_parts = 1;
+	      dvar->onepart = onepart;
+	      dvar->in_changed_variables = false;
+	      dvar->var_part[0].loc_chain = node;
+	      dvar->var_part[0].cur_loc = NULL;
+	      if (onepart)
+		VAR_LOC_1PAUX (dvar) = NULL;
+	      else
+		VAR_PART_OFFSET (dvar, 0) = 0;
+
+	      dstslot
+		= shared_hash_find_slot_unshare_1 (&dst->vars, dv, dvhash,
+						   INSERT);
+	      gcc_assert (!*dstslot);
+	      *dstslot = dvar;
+	    }
+	  else
+	    return 1;
+	}
+    }
+
+  nodep = &dvar->var_part[0].loc_chain;
+  while ((node = *nodep))
+    {
+      location_chain *nextp = &node->next;
+
+      if (GET_CODE (node->loc) == REG)
+	{
+	  attrs list;
+
+	  for (list = dst->regs[REGNO (node->loc)]; list; list = list->next)
+	    if (GET_MODE (node->loc) == GET_MODE (list->loc)
+		&& dv_is_value_p (list->dv))
+	      break;
+
+	  if (!list)
+	    attrs_list_insert (&dst->regs[REGNO (node->loc)],
+			       dv, 0, node->loc);
+	  /* If this value became canonical for another value that had
+	     this register, we want to leave it alone.  */
+	  else if (dv_as_value (list->dv) != val)
+	    {
+	      dstslot = set_slot_part (dst, dv_as_value (list->dv),
+				       dstslot, dv, 0,
+				       node->init, NULL_RTX);
+	      dstslot = delete_slot_part (dst, node->loc, dstslot, 0);
+
+	      /* Since nextp points into the removed node, we can't
+		 use it.  The pointer to the next node moved to nodep.
+		 However, if the variable we're walking is unshared
+		 during our walk, we'll keep walking the location list
+		 of the previously-shared variable, in which case the
+		 node won't have been removed, and we'll want to skip
+		 it.  That's why we test *nodep here.  */
+	      if (*nodep != node)
+		nextp = nodep;
+	    }
+	}
+      else
+	/* Canonicalization puts registers first, so we don't have to
+	   walk it all.  */
+	break;
+      nodep = nextp;
+    }
+
+  if (dvar != *dstslot)
+    dvar = *dstslot;
+  nodep = &dvar->var_part[0].loc_chain;
+
+  if (val)
+    {
+      /* Mark all referenced nodes for canonicalization, and make sure
+	 we have mutual equivalence links.  */
+      VALUE_RECURSED_INTO (val) = true;
+      for (node = *nodep; node; node = node->next)
+	if (GET_CODE (node->loc) == VALUE)
+	  {
+	    VALUE_RECURSED_INTO (node->loc) = true;
+	    set_variable_part (dst, val, dv_from_value (node->loc), 0,
+			       node->init, NULL, INSERT);
+	  }
+
+      dstslot = shared_hash_find_slot_noinsert_1 (dst->vars, dv, dvhash);
+      gcc_assert (*dstslot == dvar);
+      canonicalize_values_star (dstslot, dst);
+      gcc_checking_assert (dstslot
+			   == shared_hash_find_slot_noinsert_1 (dst->vars,
+								dv, dvhash));
+      dvar = *dstslot;
+    }
+  else
+    {
+      bool has_value = false, has_other = false;
+
+      /* If we have one value and anything else, we're going to
+	 canonicalize this, so make sure all values have an entry in
+	 the table and are marked for canonicalization.  */
+      for (node = *nodep; node; node = node->next)
+	{
+	  if (GET_CODE (node->loc) == VALUE)
+	    {
+	      /* If this was marked during register canonicalization,
+		 we know we have to canonicalize values.  */
+	      if (has_value)
+		has_other = true;
+	      has_value = true;
+	      if (has_other)
+		break;
+	    }
+	  else
+	    {
+	      has_other = true;
+	      if (has_value)
+		break;
+	    }
+	}
+
+      if (has_value && has_other)
+	{
+	  for (node = *nodep; node; node = node->next)
+	    {
+	      if (GET_CODE (node->loc) == VALUE)
+		{
+		  decl_or_value dv = dv_from_value (node->loc);
+		  variable_def **slot = NULL;
+
+		  if (shared_hash_shared (dst->vars))
+		    slot = shared_hash_find_slot_noinsert (dst->vars, dv);
+		  if (!slot)
+		    slot = shared_hash_find_slot_unshare (&dst->vars, dv,
+							  INSERT);
+		  if (!*slot)
+		    {
+		      variable var = (variable) pool_alloc (onepart_pool
+							    (ONEPART_VALUE));
+		      var->dv = dv;
+		      var->refcount = 1;
+		      var->n_var_parts = 1;
+		      var->onepart = ONEPART_VALUE;
+		      var->in_changed_variables = false;
+		      var->var_part[0].loc_chain = NULL;
+		      var->var_part[0].cur_loc = NULL;
+		      VAR_LOC_1PAUX (var) = NULL;
+		      *slot = var;
+		    }
+
+		  VALUE_RECURSED_INTO (node->loc) = true;
+		}
+	    }
+
+	  dstslot = shared_hash_find_slot_noinsert_1 (dst->vars, dv, dvhash);
+	  gcc_assert (*dstslot == dvar);
+	  canonicalize_values_star (dstslot, dst);
+	  gcc_checking_assert (dstslot
+			       == shared_hash_find_slot_noinsert_1 (dst->vars,
+								    dv, dvhash));
+	  dvar = *dstslot;
+	}
+    }
+
+  if (!onepart_variable_different_p (dvar, s2var))
+    {
+      variable_htab_free (dvar);
+      *dstslot = dvar = s2var;
+      dvar->refcount++;
+    }
+  else if (s2var != s1var && !onepart_variable_different_p (dvar, s1var))
+    {
+      variable_htab_free (dvar);
+      *dstslot = dvar = s1var;
+      dvar->refcount++;
+      dst_can_be_shared = false;
+    }
+  else
+    dst_can_be_shared = false;
+
+  return 1;
+}
+
+/* Copy s2slot (in DSM->src) to DSM->dst if the variable is a
+   multi-part variable.  Unions of multi-part variables and
+   intersections of one-part ones will be handled in
+   variable_merge_over_cur().  */
+
+static int
+variable_merge_over_src (variable s2var, struct dfset_merge *dsm)
+{
+  dataflow_set *dst = dsm->dst;
+  decl_or_value dv = s2var->dv;
+
+  if (!s2var->onepart)
+    {
+      variable_def **dstp = shared_hash_find_slot (dst->vars, dv);
+      *dstp = s2var;
+      s2var->refcount++;
+      return 1;
+    }
+
+  dsm->src_onepart_cnt++;
+  return 1;
+}
+
+/* Combine dataflow set information from SRC2 into DST, using PDST
+   to carry over information across passes.  */
+
+static void
+dataflow_set_merge (dataflow_set *dst, dataflow_set *src2)
+{
+  dataflow_set cur = *dst;
+  dataflow_set *src1 = &cur;
+  struct dfset_merge dsm;
+  int i;
+  size_t src1_elems, src2_elems;
+  variable_iterator_type hi;
+  variable var;
+
+  src1_elems = shared_hash_htab (src1->vars).elements ();
+  src2_elems = shared_hash_htab (src2->vars).elements ();
+  dataflow_set_init (dst);
+  dst->stack_adjust = cur.stack_adjust;
+  shared_hash_destroy (dst->vars);
+  dst->vars = (shared_hash) pool_alloc (shared_hash_pool);
+  dst->vars->refcount = 1;
+  dst->vars->htab.create (MAX (src1_elems, src2_elems));
+
+  for (i = 0; i < FIRST_PSEUDO_REGISTER; i++)
+    attrs_list_mpdv_union (&dst->regs[i], src1->regs[i], src2->regs[i]);
+
+  dsm.dst = dst;
+  dsm.src = src2;
+  dsm.cur = src1;
+  dsm.src_onepart_cnt = 0;
+
+  FOR_EACH_HASH_TABLE_ELEMENT (shared_hash_htab (dsm.src->vars),
+			       var, variable, hi)
+    variable_merge_over_src (var, &dsm);
+  FOR_EACH_HASH_TABLE_ELEMENT (shared_hash_htab (dsm.cur->vars),
+			       var, variable, hi)
+    variable_merge_over_cur (var, &dsm);
+
+  if (dsm.src_onepart_cnt)
+    dst_can_be_shared = false;
+
+  dataflow_set_destroy (src1);
+}
+
+/* Mark register equivalences.  */
+
+static void
+dataflow_set_equiv_regs (dataflow_set *set)
+{
+  int i;
+  attrs list, *listp;
+
+  for (i = 0; i < FIRST_PSEUDO_REGISTER; i++)
+    {
+      rtx canon[NUM_MACHINE_MODES];
+
+      /* If the list is empty or one entry, no need to canonicalize
+	 anything.  */
+      if (set->regs[i] == NULL || set->regs[i]->next == NULL)
+	continue;
+
+      memset (canon, 0, sizeof (canon));
+
+      for (list = set->regs[i]; list; list = list->next)
+	if (list->offset == 0 && dv_is_value_p (list->dv))
+	  {
+	    rtx val = dv_as_value (list->dv);
+	    rtx *cvalp = &canon[(int)GET_MODE (val)];
+	    rtx cval = *cvalp;
+
+	    if (canon_value_cmp (val, cval))
+	      *cvalp = val;
+	  }
+
+      for (list = set->regs[i]; list; list = list->next)
+	if (list->offset == 0 && dv_onepart_p (list->dv))
+	  {
+	    rtx cval = canon[(int)GET_MODE (list->loc)];
+
+	    if (!cval)
+	      continue;
+
+	    if (dv_is_value_p (list->dv))
+	      {
+		rtx val = dv_as_value (list->dv);
+
+		if (val == cval)
+		  continue;
+
+		VALUE_RECURSED_INTO (val) = true;
+		set_variable_part (set, val, dv_from_value (cval), 0,
+				   VAR_INIT_STATUS_INITIALIZED,
+				   NULL, NO_INSERT);
+	      }
+
+	    VALUE_RECURSED_INTO (cval) = true;
+	    set_variable_part (set, cval, list->dv, 0,
+			       VAR_INIT_STATUS_INITIALIZED, NULL, NO_INSERT);
+	  }
+
+      for (listp = &set->regs[i]; (list = *listp);
+	   listp = list ? &list->next : listp)
+	if (list->offset == 0 && dv_onepart_p (list->dv))
+	  {
+	    rtx cval = canon[(int)GET_MODE (list->loc)];
+	    variable_def **slot;
+
+	    if (!cval)
+	      continue;
+
+	    if (dv_is_value_p (list->dv))
+	      {
+		rtx val = dv_as_value (list->dv);
+		if (!VALUE_RECURSED_INTO (val))
+		  continue;
+	      }
+
+	    slot = shared_hash_find_slot_noinsert (set->vars, list->dv);
+	    canonicalize_values_star (slot, set);
+	    if (*listp != list)
+	      list = NULL;
+	  }
+    }
+}
+
+/* Remove any redundant values in the location list of VAR, which must
+   be unshared and 1-part.  */
+
+static void
+remove_duplicate_values (variable var)
+{
+  location_chain node, *nodep;
+
+  gcc_assert (var->onepart);
+  gcc_assert (var->n_var_parts == 1);
+  gcc_assert (var->refcount == 1);
+
+  for (nodep = &var->var_part[0].loc_chain; (node = *nodep); )
+    {
+      if (GET_CODE (node->loc) == VALUE)
+	{
+	  if (VALUE_RECURSED_INTO (node->loc))
+	    {
+	      /* Remove duplicate value node.  */
+	      *nodep = node->next;
+	      pool_free (loc_chain_pool, node);
+	      continue;
+	    }
+	  else
+	    VALUE_RECURSED_INTO (node->loc) = true;
+	}
+      nodep = &node->next;
+    }
+
+  for (node = var->var_part[0].loc_chain; node; node = node->next)
+    if (GET_CODE (node->loc) == VALUE)
+      {
+	gcc_assert (VALUE_RECURSED_INTO (node->loc));
+	VALUE_RECURSED_INTO (node->loc) = false;
+      }
+}
+
+
+/* Hash table iteration argument passed to variable_post_merge.  */
+struct dfset_post_merge
+{
+  /* The new input set for the current block.  */
+  dataflow_set *set;
+  /* Pointer to the permanent input set for the current block, or
+     NULL.  */
+  dataflow_set **permp;
+};
+
+/* Create values for incoming expressions associated with one-part
+   variables that don't have value numbers for them.  */
+
+int
+variable_post_merge_new_vals (variable_def **slot, dfset_post_merge *dfpm)
+{
+  dataflow_set *set = dfpm->set;
+  variable var = *slot;
+  location_chain node;
+
+  if (!var->onepart || !var->n_var_parts)
+    return 1;
+
+  gcc_assert (var->n_var_parts == 1);
+
+  if (dv_is_decl_p (var->dv))
+    {
+      bool check_dupes = false;
+
+    restart:
+      for (node = var->var_part[0].loc_chain; node; node = node->next)
+	{
+	  if (GET_CODE (node->loc) == VALUE)
+	    gcc_assert (!VALUE_RECURSED_INTO (node->loc));
+	  else if (GET_CODE (node->loc) == REG)
+	    {
+	      attrs att, *attp, *curp = NULL;
+
+	      if (var->refcount != 1)
+		{
+		  slot = unshare_variable (set, slot, var,
+					   VAR_INIT_STATUS_INITIALIZED);
+		  var = *slot;
+		  goto restart;
+		}
+
+	      for (attp = &set->regs[REGNO (node->loc)]; (att = *attp);
+		   attp = &att->next)
+		if (att->offset == 0
+		    && GET_MODE (att->loc) == GET_MODE (node->loc))
+		  {
+		    if (dv_is_value_p (att->dv))
+		      {
+			rtx cval = dv_as_value (att->dv);
+			node->loc = cval;
+			check_dupes = true;
+			break;
+		      }
+		    else if (dv_as_opaque (att->dv) == dv_as_opaque (var->dv))
+		      curp = attp;
+		  }
+
+	      if (!curp)
+		{
+		  curp = attp;
+		  while (*curp)
+		    if ((*curp)->offset == 0
+			&& GET_MODE ((*curp)->loc) == GET_MODE (node->loc)
+			&& dv_as_opaque ((*curp)->dv) == dv_as_opaque (var->dv))
+		      break;
+		    else
+		      curp = &(*curp)->next;
+		  gcc_assert (*curp);
+		}
+
+	      if (!att)
+		{
+		  decl_or_value cdv;
+		  rtx cval;
+
+		  if (!*dfpm->permp)
+		    {
+		      *dfpm->permp = XNEW (dataflow_set);
+		      dataflow_set_init (*dfpm->permp);
+		    }
+
+		  for (att = (*dfpm->permp)->regs[REGNO (node->loc)];
+		       att; att = att->next)
+		    if (GET_MODE (att->loc) == GET_MODE (node->loc))
+		      {
+			gcc_assert (att->offset == 0
+				    && dv_is_value_p (att->dv));
+			val_reset (set, att->dv);
+			break;
+		      }
+
+		  if (att)
+		    {
+		      cdv = att->dv;
+		      cval = dv_as_value (cdv);
+		    }
+		  else
+		    {
+		      /* Create a unique value to hold this register,
+			 that ought to be found and reused in
+			 subsequent rounds.  */
+		      cselib_val *v;
+		      gcc_assert (!cselib_lookup (node->loc,
+						  GET_MODE (node->loc), 0,
+						  VOIDmode));
+		      v = cselib_lookup (node->loc, GET_MODE (node->loc), 1,
+					 VOIDmode);
+		      cselib_preserve_value (v);
+		      cselib_invalidate_rtx (node->loc);
+		      cval = v->val_rtx;
+		      cdv = dv_from_value (cval);
+		      if (dump_file)
+			fprintf (dump_file,
+				 "Created new value %u:%u for reg %i\n",
+				 v->uid, v->hash, REGNO (node->loc));
+		    }
+
+		  var_reg_decl_set (*dfpm->permp, node->loc,
+				    VAR_INIT_STATUS_INITIALIZED,
+				    cdv, 0, NULL, INSERT);
+
+		  node->loc = cval;
+		  check_dupes = true;
+		}
+
+	      /* Remove attribute referring to the decl, which now
+		 uses the value for the register, already existing or
+		 to be added when we bring perm in.  */
+	      att = *curp;
+	      *curp = att->next;
+	      pool_free (attrs_pool, att);
+	    }
+	}
+
+      if (check_dupes)
+	remove_duplicate_values (var);
+    }
+
+  return 1;
+}
+
+/* Reset values in the permanent set that are not associated with the
+   chosen expression.  */
+
+int
+variable_post_merge_perm_vals (variable_def **pslot, dfset_post_merge *dfpm)
+{
+  dataflow_set *set = dfpm->set;
+  variable pvar = *pslot, var;
+  location_chain pnode;
+  decl_or_value dv;
+  attrs att;
+
+  gcc_assert (dv_is_value_p (pvar->dv)
+	      && pvar->n_var_parts == 1);
+  pnode = pvar->var_part[0].loc_chain;
+  gcc_assert (pnode
+	      && !pnode->next
+	      && REG_P (pnode->loc));
+
+  dv = pvar->dv;
+
+  var = shared_hash_find (set->vars, dv);
+  if (var)
+    {
+      /* Although variable_post_merge_new_vals may have made decls
+	 non-star-canonical, values that pre-existed in canonical form
+	 remain canonical, and newly-created values reference a single
+	 REG, so they are canonical as well.  Since VAR has the
+	 location list for a VALUE, using find_loc_in_1pdv for it is
+	 fine, since VALUEs don't map back to DECLs.  */
+      if (find_loc_in_1pdv (pnode->loc, var, shared_hash_htab (set->vars)))
+	return 1;
+      val_reset (set, dv);
+    }
+
+  for (att = set->regs[REGNO (pnode->loc)]; att; att = att->next)
+    if (att->offset == 0
+	&& GET_MODE (att->loc) == GET_MODE (pnode->loc)
+	&& dv_is_value_p (att->dv))
+      break;
+
+  /* If there is a value associated with this register already, create
+     an equivalence.  */
+  if (att && dv_as_value (att->dv) != dv_as_value (dv))
+    {
+      rtx cval = dv_as_value (att->dv);
+      set_variable_part (set, cval, dv, 0, pnode->init, NULL, INSERT);
+      set_variable_part (set, dv_as_value (dv), att->dv, 0, pnode->init,
+			 NULL, INSERT);
+    }
+  else if (!att)
+    {
+      attrs_list_insert (&set->regs[REGNO (pnode->loc)],
+			 dv, 0, pnode->loc);
+      variable_union (pvar, set);
+    }
+
+  return 1;
+}
+
+/* Just checking stuff and registering register attributes for
+   now.  */
+
+static void
+dataflow_post_merge_adjust (dataflow_set *set, dataflow_set **permp)
+{
+  struct dfset_post_merge dfpm;
+
+  dfpm.set = set;
+  dfpm.permp = permp;
+
+  shared_hash_htab (set->vars)
+    .traverse <dfset_post_merge*, variable_post_merge_new_vals> (&dfpm);
+  if (*permp)
+    shared_hash_htab ((*permp)->vars)
+      .traverse <dfset_post_merge*, variable_post_merge_perm_vals> (&dfpm);
+  shared_hash_htab (set->vars)
+    .traverse <dataflow_set *, canonicalize_values_star> (set);
+  shared_hash_htab (set->vars)
+    .traverse <dataflow_set *, canonicalize_vars_star> (set);
+}
+
+/* Return a node whose loc is a MEM that refers to EXPR in the
+   location list of a one-part variable or value VAR, or in that of
+   any values recursively mentioned in the location lists.  */
+
+static location_chain
+find_mem_expr_in_1pdv (tree expr, rtx val, variable_table_type vars)
+{
+  location_chain node;
+  decl_or_value dv;
+  variable var;
+  location_chain where = NULL;
+
+  if (!val)
+    return NULL;
+
+  gcc_assert (GET_CODE (val) == VALUE
+	      && !VALUE_RECURSED_INTO (val));
+
+  dv = dv_from_value (val);
+  var = vars.find_with_hash (dv, dv_htab_hash (dv));
+
+  if (!var)
+    return NULL;
+
+  gcc_assert (var->onepart);
+
+  if (!var->n_var_parts)
+    return NULL;
+
+  VALUE_RECURSED_INTO (val) = true;
+
+  for (node = var->var_part[0].loc_chain; node; node = node->next)
+    if (MEM_P (node->loc)
+	&& MEM_EXPR (node->loc) == expr
+	&& INT_MEM_OFFSET (node->loc) == 0)
+      {
+	where = node;
+	break;
+      }
+    else if (GET_CODE (node->loc) == VALUE
+	     && !VALUE_RECURSED_INTO (node->loc)
+	     && (where = find_mem_expr_in_1pdv (expr, node->loc, vars)))
+      break;
+
+  VALUE_RECURSED_INTO (val) = false;
+
+  return where;
+}
+
+/* Return TRUE if the value of MEM may vary across a call.  */
+
+static bool
+mem_dies_at_call (rtx mem)
+{
+  tree expr = MEM_EXPR (mem);
+  tree decl;
+
+  if (!expr)
+    return true;
+
+  decl = get_base_address (expr);
+
+  if (!decl)
+    return true;
+
+  if (!DECL_P (decl))
+    return true;
+
+  return (may_be_aliased (decl)
+	  || (!TREE_READONLY (decl) && is_global_var (decl)));
+}
+
+/* Remove all MEMs from the location list of a hash table entry for a
+   one-part variable, except those whose MEM attributes map back to
+   the variable itself, directly or within a VALUE.  */
+
+int
+dataflow_set_preserve_mem_locs (variable_def **slot, dataflow_set *set)
+{
+  variable var = *slot;
+
+  if (var->onepart == ONEPART_VDECL || var->onepart == ONEPART_DEXPR)
+    {
+      tree decl = dv_as_decl (var->dv);
+      location_chain loc, *locp;
+      bool changed = false;
+
+      if (!var->n_var_parts)
+	return 1;
+
+      gcc_assert (var->n_var_parts == 1);
+
+      if (shared_var_p (var, set->vars))
+	{
+	  for (loc = var->var_part[0].loc_chain; loc; loc = loc->next)
+	    {
+	      /* We want to remove dying MEMs that doesn't refer to DECL.  */
+	      if (GET_CODE (loc->loc) == MEM
+		  && (MEM_EXPR (loc->loc) != decl
+		      || INT_MEM_OFFSET (loc->loc) != 0)
+		  && !mem_dies_at_call (loc->loc))
+		break;
+	      /* We want to move here MEMs that do refer to DECL.  */
+	      else if (GET_CODE (loc->loc) == VALUE
+		       && find_mem_expr_in_1pdv (decl, loc->loc,
+						 shared_hash_htab (set->vars)))
+		break;
+	    }
+
+	  if (!loc)
+	    return 1;
+
+	  slot = unshare_variable (set, slot, var, VAR_INIT_STATUS_UNKNOWN);
+	  var = *slot;
+	  gcc_assert (var->n_var_parts == 1);
+	}
+
+      for (locp = &var->var_part[0].loc_chain, loc = *locp;
+	   loc; loc = *locp)
+	{
+	  rtx old_loc = loc->loc;
+	  if (GET_CODE (old_loc) == VALUE)
+	    {
+	      location_chain mem_node
+		= find_mem_expr_in_1pdv (decl, loc->loc,
+					 shared_hash_htab (set->vars));
+
+	      /* ??? This picks up only one out of multiple MEMs that
+		 refer to the same variable.  Do we ever need to be
+		 concerned about dealing with more than one, or, given
+		 that they should all map to the same variable
+		 location, their addresses will have been merged and
+		 they will be regarded as equivalent?  */
+	      if (mem_node)
+		{
+		  loc->loc = mem_node->loc;
+		  loc->set_src = mem_node->set_src;
+		  loc->init = MIN (loc->init, mem_node->init);
+		}
+	    }
+
+	  if (GET_CODE (loc->loc) != MEM
+	      || (MEM_EXPR (loc->loc) == decl
+		  && INT_MEM_OFFSET (loc->loc) == 0)
+	      || !mem_dies_at_call (loc->loc))
+	    {
+	      if (old_loc != loc->loc && emit_notes)
+		{
+		  if (old_loc == var->var_part[0].cur_loc)
+		    {
+		      changed = true;
+		      var->var_part[0].cur_loc = NULL;
+		    }
+		}
+	      locp = &loc->next;
+	      continue;
+	    }
+
+	  if (emit_notes)
+	    {
+	      if (old_loc == var->var_part[0].cur_loc)
+		{
+		  changed = true;
+		  var->var_part[0].cur_loc = NULL;
+		}
+	    }
+	  *locp = loc->next;
+	  pool_free (loc_chain_pool, loc);
+	}
+
+      if (!var->var_part[0].loc_chain)
+	{
+	  var->n_var_parts--;
+	  changed = true;
+	}
+      if (changed)
+	variable_was_changed (var, set);
+    }
+
+  return 1;
+}
+
+/* Remove all MEMs from the location list of a hash table entry for a
+   value.  */
+
+int
+dataflow_set_remove_mem_locs (variable_def **slot, dataflow_set *set)
+{
+  variable var = *slot;
+
+  if (var->onepart == ONEPART_VALUE)
+    {
+      location_chain loc, *locp;
+      bool changed = false;
+      rtx cur_loc;
+
+      gcc_assert (var->n_var_parts == 1);
+
+      if (shared_var_p (var, set->vars))
+	{
+	  for (loc = var->var_part[0].loc_chain; loc; loc = loc->next)
+	    if (GET_CODE (loc->loc) == MEM
+		&& mem_dies_at_call (loc->loc))
+	      break;
+
+	  if (!loc)
+	    return 1;
+
+	  slot = unshare_variable (set, slot, var, VAR_INIT_STATUS_UNKNOWN);
+	  var = *slot;
+	  gcc_assert (var->n_var_parts == 1);
+	}
+
+      if (VAR_LOC_1PAUX (var))
+	cur_loc = VAR_LOC_FROM (var);
+      else
+	cur_loc = var->var_part[0].cur_loc;
+
+      for (locp = &var->var_part[0].loc_chain, loc = *locp;
+	   loc; loc = *locp)
+	{
+	  if (GET_CODE (loc->loc) != MEM
+	      || !mem_dies_at_call (loc->loc))
+	    {
+	      locp = &loc->next;
+	      continue;
+	    }
+
+	  *locp = loc->next;
+	  /* If we have deleted the location which was last emitted
+	     we have to emit new location so add the variable to set
+	     of changed variables.  */
+	  if (cur_loc == loc->loc)
+	    {
+	      changed = true;
+	      var->var_part[0].cur_loc = NULL;
+	      if (VAR_LOC_1PAUX (var))
+		VAR_LOC_FROM (var) = NULL;
+	    }
+	  pool_free (loc_chain_pool, loc);
+	}
+
+      if (!var->var_part[0].loc_chain)
+	{
+	  var->n_var_parts--;
+	  changed = true;
+	}
+      if (changed)
+	variable_was_changed (var, set);
+    }
+
+  return 1;
+}
+
+/* Remove all variable-location information about call-clobbered
+   registers, as well as associations between MEMs and VALUEs.  */
+
+static void
+dataflow_set_clear_at_call (dataflow_set *set)
+{
+  unsigned int r;
+  hard_reg_set_iterator hrsi;
+
+  EXECUTE_IF_SET_IN_HARD_REG_SET (regs_invalidated_by_call, 0, r, hrsi)
+    var_regno_delete (set, r);
+
+  if (MAY_HAVE_DEBUG_INSNS)
+    {
+      set->traversed_vars = set->vars;
+      shared_hash_htab (set->vars)
+	.traverse <dataflow_set *, dataflow_set_preserve_mem_locs> (set);
+      set->traversed_vars = set->vars;
+      shared_hash_htab (set->vars)
+	.traverse <dataflow_set *, dataflow_set_remove_mem_locs> (set);
+      set->traversed_vars = NULL;
+    }
+}
+
+static bool
+variable_part_different_p (variable_part *vp1, variable_part *vp2)
+{
+  location_chain lc1, lc2;
+
+  for (lc1 = vp1->loc_chain; lc1; lc1 = lc1->next)
+    {
+      for (lc2 = vp2->loc_chain; lc2; lc2 = lc2->next)
+	{
+	  if (REG_P (lc1->loc) && REG_P (lc2->loc))
+	    {
+	      if (REGNO (lc1->loc) == REGNO (lc2->loc))
+		break;
+	    }
+	  if (rtx_equal_p (lc1->loc, lc2->loc))
+	    break;
+	}
+      if (!lc2)
+	return true;
+    }
+  return false;
+}
+
+/* Return true if one-part variables VAR1 and VAR2 are different.
+   They must be in canonical order.  */
+
+static bool
+onepart_variable_different_p (variable var1, variable var2)
+{
+  location_chain lc1, lc2;
+
+  if (var1 == var2)
+    return false;
+
+  gcc_assert (var1->n_var_parts == 1
+	      && var2->n_var_parts == 1);
+
+  lc1 = var1->var_part[0].loc_chain;
+  lc2 = var2->var_part[0].loc_chain;
+
+  gcc_assert (lc1 && lc2);
+
+  while (lc1 && lc2)
+    {
+      if (loc_cmp (lc1->loc, lc2->loc))
+	return true;
+      lc1 = lc1->next;
+      lc2 = lc2->next;
+    }
+
+  return lc1 != lc2;
+}
+
+/* Return true if variables VAR1 and VAR2 are different.  */
+
+static bool
+variable_different_p (variable var1, variable var2)
+{
+  int i;
+
+  if (var1 == var2)
+    return false;
+
+  if (var1->onepart != var2->onepart)
+    return true;
+
+  if (var1->n_var_parts != var2->n_var_parts)
+    return true;
+
+  if (var1->onepart && var1->n_var_parts)
+    {
+      gcc_checking_assert (dv_as_opaque (var1->dv) == dv_as_opaque (var2->dv)
+			   && var1->n_var_parts == 1);
+      /* One-part values have locations in a canonical order.  */
+      return onepart_variable_different_p (var1, var2);
+    }
+
+  for (i = 0; i < var1->n_var_parts; i++)
+    {
+      if (VAR_PART_OFFSET (var1, i) != VAR_PART_OFFSET (var2, i))
+	return true;
+      if (variable_part_different_p (&var1->var_part[i], &var2->var_part[i]))
+	return true;
+      if (variable_part_different_p (&var2->var_part[i], &var1->var_part[i]))
+	return true;
+    }
+  return false;
+}
+
+/* Return true if dataflow sets OLD_SET and NEW_SET differ.  */
+
+static bool
+dataflow_set_different (dataflow_set *old_set, dataflow_set *new_set)
+{
+  variable_iterator_type hi;
+  variable var1;
+
+  if (old_set->vars == new_set->vars)
+    return false;
+
+  if (shared_hash_htab (old_set->vars).elements ()
+      != shared_hash_htab (new_set->vars).elements ())
+    return true;
+
+  FOR_EACH_HASH_TABLE_ELEMENT (shared_hash_htab (old_set->vars),
+			       var1, variable, hi)
+    {
+      variable_table_type htab = shared_hash_htab (new_set->vars);
+      variable var2 = htab.find_with_hash (var1->dv, dv_htab_hash (var1->dv));
+      if (!var2)
+	{
+	  if (dump_file && (dump_flags & TDF_DETAILS))
+	    {
+	      fprintf (dump_file, "dataflow difference found: removal of:\n");
+	      dump_var (var1);
+	    }
+	  return true;
+	}
+
+      if (variable_different_p (var1, var2))
+	{
+	  if (dump_file && (dump_flags & TDF_DETAILS))
+	    {
+	      fprintf (dump_file, "dataflow difference found: "
+		       "old and new follow:\n");
+	      dump_var (var1);
+	      dump_var (var2);
+	    }
+	  return true;
+	}
+    }
+
+  /* No need to traverse the second hashtab, if both have the same number
+     of elements and the second one had all entries found in the first one,
+     then it can't have any extra entries.  */
+  return false;
+}
+
+/* Free the contents of dataflow set SET.  */
+
+static void
+dataflow_set_destroy (dataflow_set *set)
+{
+  int i;
+
+  for (i = 0; i < FIRST_PSEUDO_REGISTER; i++)
+    attrs_list_clear (&set->regs[i]);
+
+  shared_hash_destroy (set->vars);
+  set->vars = NULL;
+}
+
+/* Return true if RTL X contains a SYMBOL_REF.  */
+
+static bool
+contains_symbol_ref (rtx x)
+{
+  const char *fmt;
+  RTX_CODE code;
+  int i;
+
+  if (!x)
+    return false;
+
+  code = GET_CODE (x);
+  if (code == SYMBOL_REF)
+    return true;
+
+  fmt = GET_RTX_FORMAT (code);
+  for (i = GET_RTX_LENGTH (code) - 1; i >= 0; i--)
+    {
+      if (fmt[i] == 'e')
+	{
+	  if (contains_symbol_ref (XEXP (x, i)))
+	    return true;
+	}
+      else if (fmt[i] == 'E')
+	{
+	  int j;
+	  for (j = 0; j < XVECLEN (x, i); j++)
+	    if (contains_symbol_ref (XVECEXP (x, i, j)))
+	      return true;
+	}
+    }
+
+  return false;
+}
+
+/* Shall EXPR be tracked?  */
+
+static bool
+track_expr_p (tree expr, bool need_rtl)
+{
+  rtx decl_rtl;
+  tree realdecl;
+
+  if (TREE_CODE (expr) == DEBUG_EXPR_DECL)
+    return DECL_RTL_SET_P (expr);
+
+  /* If EXPR is not a parameter or a variable do not track it.  */
+  if (TREE_CODE (expr) != VAR_DECL && TREE_CODE (expr) != PARM_DECL)
+    return 0;
+
+  /* It also must have a name...  */
+  if (!DECL_NAME (expr) && need_rtl)
+    return 0;
+
+  /* ... and a RTL assigned to it.  */
+  decl_rtl = DECL_RTL_IF_SET (expr);
+  if (!decl_rtl && need_rtl)
+    return 0;
+
+  /* If this expression is really a debug alias of some other declaration, we
+     don't need to track this expression if the ultimate declaration is
+     ignored.  */
+  realdecl = expr;
+  if (TREE_CODE (realdecl) == VAR_DECL && DECL_HAS_DEBUG_EXPR_P (realdecl))
+    {
+      realdecl = DECL_DEBUG_EXPR (realdecl);
+      if (!DECL_P (realdecl))
+	{
+	  if (handled_component_p (realdecl)
+	      || (TREE_CODE (realdecl) == MEM_REF
+		  && TREE_CODE (TREE_OPERAND (realdecl, 0)) == ADDR_EXPR))
+	    {
+	      HOST_WIDE_INT bitsize, bitpos, maxsize;
+	      tree innerdecl
+		= get_ref_base_and_extent (realdecl, &bitpos, &bitsize,
+					   &maxsize);
+	      if (!DECL_P (innerdecl)
+		  || DECL_IGNORED_P (innerdecl)
+		  /* Do not track declarations for parts of tracked parameters
+		     since we want to track them as a whole instead.  */
+		  || (TREE_CODE (innerdecl) == PARM_DECL
+		      && DECL_MODE (innerdecl) != BLKmode
+		      && TREE_CODE (TREE_TYPE (innerdecl)) != UNION_TYPE)
+		  || TREE_STATIC (innerdecl)
+		  || bitsize <= 0
+		  || bitpos + bitsize > 256
+		  || bitsize != maxsize)
+		return 0;
+	      else
+		realdecl = expr;
+	    }
+	  else
+	    return 0;
+	}
+    }
+
+  /* Do not track EXPR if REALDECL it should be ignored for debugging
+     purposes.  */
+  if (DECL_IGNORED_P (realdecl))
+    return 0;
+
+  /* Do not track global variables until we are able to emit correct location
+     list for them.  */
+  if (TREE_STATIC (realdecl))
+    return 0;
+
+  /* When the EXPR is a DECL for alias of some variable (see example)
+     the TREE_STATIC flag is not used.  Disable tracking all DECLs whose
+     DECL_RTL contains SYMBOL_REF.
+
+     Example:
+     extern char **_dl_argv_internal __attribute__ ((alias ("_dl_argv")));
+     char **_dl_argv;
+  */
+  if (decl_rtl && MEM_P (decl_rtl)
+      && contains_symbol_ref (XEXP (decl_rtl, 0)))
+    return 0;
+
+  /* If RTX is a memory it should not be very large (because it would be
+     an array or struct).  */
+  if (decl_rtl && MEM_P (decl_rtl))
+    {
+      /* Do not track structures and arrays.  */
+      if (GET_MODE (decl_rtl) == BLKmode
+	  || AGGREGATE_TYPE_P (TREE_TYPE (realdecl)))
+	return 0;
+      if (MEM_SIZE_KNOWN_P (decl_rtl)
+	  && MEM_SIZE (decl_rtl) > MAX_VAR_PARTS)
+	return 0;
+    }
+
+  DECL_CHANGED (expr) = 0;
+  DECL_CHANGED (realdecl) = 0;
+  return 1;
+}
+
+/* Determine whether a given LOC refers to the same variable part as
+   EXPR+OFFSET.  */
+
+static bool
+same_variable_part_p (rtx loc, tree expr, HOST_WIDE_INT offset)
+{
+  tree expr2;
+  HOST_WIDE_INT offset2;
+
+  if (! DECL_P (expr))
+    return false;
+
+  if (REG_P (loc))
+    {
+      expr2 = REG_EXPR (loc);
+      offset2 = REG_OFFSET (loc);
+    }
+  else if (MEM_P (loc))
+    {
+      expr2 = MEM_EXPR (loc);
+      offset2 = INT_MEM_OFFSET (loc);
+    }
+  else
+    return false;
+
+  if (! expr2 || ! DECL_P (expr2))
+    return false;
+
+  expr = var_debug_decl (expr);
+  expr2 = var_debug_decl (expr2);
+
+  return (expr == expr2 && offset == offset2);
+}
+
+/* LOC is a REG or MEM that we would like to track if possible.
+   If EXPR is null, we don't know what expression LOC refers to,
+   otherwise it refers to EXPR + OFFSET.  STORE_REG_P is true if
+   LOC is an lvalue register.
+
+   Return true if EXPR is nonnull and if LOC, or some lowpart of it,
+   is something we can track.  When returning true, store the mode of
+   the lowpart we can track in *MODE_OUT (if nonnull) and its offset
+   from EXPR in *OFFSET_OUT (if nonnull).  */
+
+static bool
+track_loc_p (rtx loc, tree expr, HOST_WIDE_INT offset, bool store_reg_p,
+	     enum machine_mode *mode_out, HOST_WIDE_INT *offset_out)
+{
+  enum machine_mode mode;
+
+  if (expr == NULL || !track_expr_p (expr, true))
+    return false;
+
+  /* If REG was a paradoxical subreg, its REG_ATTRS will describe the
+     whole subreg, but only the old inner part is really relevant.  */
+  mode = GET_MODE (loc);
+  if (REG_P (loc) && !HARD_REGISTER_NUM_P (ORIGINAL_REGNO (loc)))
+    {
+      enum machine_mode pseudo_mode;
+
+      pseudo_mode = PSEUDO_REGNO_MODE (ORIGINAL_REGNO (loc));
+      if (GET_MODE_SIZE (mode) > GET_MODE_SIZE (pseudo_mode))
+	{
+	  offset += byte_lowpart_offset (pseudo_mode, mode);
+	  mode = pseudo_mode;
+	}
+    }
+
+  /* If LOC is a paradoxical lowpart of EXPR, refer to EXPR itself.
+     Do the same if we are storing to a register and EXPR occupies
+     the whole of register LOC; in that case, the whole of EXPR is
+     being changed.  We exclude complex modes from the second case
+     because the real and imaginary parts are represented as separate
+     pseudo registers, even if the whole complex value fits into one
+     hard register.  */
+  if ((GET_MODE_SIZE (mode) > GET_MODE_SIZE (DECL_MODE (expr))
+       || (store_reg_p
+	   && !COMPLEX_MODE_P (DECL_MODE (expr))
+	   && hard_regno_nregs[REGNO (loc)][DECL_MODE (expr)] == 1))
+      && offset + byte_lowpart_offset (DECL_MODE (expr), mode) == 0)
+    {
+      mode = DECL_MODE (expr);
+      offset = 0;
+    }
+
+  if (offset < 0 || offset >= MAX_VAR_PARTS)
+    return false;
+
+  if (mode_out)
+    *mode_out = mode;
+  if (offset_out)
+    *offset_out = offset;
+  return true;
+}
+
+/* Return the MODE lowpart of LOC, or null if LOC is not something we
+   want to track.  When returning nonnull, make sure that the attributes
+   on the returned value are updated.  */
+
+static rtx
+var_lowpart (enum machine_mode mode, rtx loc)
+{
+  unsigned int offset, reg_offset, regno;
+
+  if (GET_MODE (loc) == mode)
+    return loc;
+
+  if (!REG_P (loc) && !MEM_P (loc))
+    return NULL;
+
+  offset = byte_lowpart_offset (mode, GET_MODE (loc));
+
+  if (MEM_P (loc))
+    return adjust_address_nv (loc, mode, offset);
+
+  reg_offset = subreg_lowpart_offset (mode, GET_MODE (loc));
+  regno = REGNO (loc) + subreg_regno_offset (REGNO (loc), GET_MODE (loc),
+					     reg_offset, mode);
+  return gen_rtx_REG_offset (loc, mode, regno, offset);
+}
+
+/* Carry information about uses and stores while walking rtx.  */
+
+struct count_use_info
+{
+  /* The insn where the RTX is.  */
+  rtx insn;
+
+  /* The basic block where insn is.  */
+  basic_block bb;
+
+  /* The array of n_sets sets in the insn, as determined by cselib.  */
+  struct cselib_set *sets;
+  int n_sets;
+
+  /* True if we're counting stores, false otherwise.  */
+  bool store_p;
+};
+
+/* Find a VALUE corresponding to X.   */
+
+static inline cselib_val *
+find_use_val (rtx x, enum machine_mode mode, struct count_use_info *cui)
+{
+  int i;
+
+  if (cui->sets)
+    {
+      /* This is called after uses are set up and before stores are
+	 processed by cselib, so it's safe to look up srcs, but not
+	 dsts.  So we look up expressions that appear in srcs or in
+	 dest expressions, but we search the sets array for dests of
+	 stores.  */
+      if (cui->store_p)
+	{
+	  /* Some targets represent memset and memcpy patterns
+	     by (set (mem:BLK ...) (reg:[QHSD]I ...)) or
+	     (set (mem:BLK ...) (const_int ...)) or
+	     (set (mem:BLK ...) (mem:BLK ...)).  Don't return anything
+	     in that case, otherwise we end up with mode mismatches.  */
+	  if (mode == BLKmode && MEM_P (x))
+	    return NULL;
+	  for (i = 0; i < cui->n_sets; i++)
+	    if (cui->sets[i].dest == x)
+	      return cui->sets[i].src_elt;
+	}
+      else
+	return cselib_lookup (x, mode, 0, VOIDmode);
+    }
+
+  return NULL;
+}
+
+/* Replace all registers and addresses in an expression with VALUE
+   expressions that map back to them, unless the expression is a
+   register.  If no mapping is or can be performed, returns NULL.  */
+
+static rtx
+replace_expr_with_values (rtx loc)
+{
+  if (REG_P (loc) || GET_CODE (loc) == ENTRY_VALUE)
+    return NULL;
+  else if (MEM_P (loc))
+    {
+      cselib_val *addr = cselib_lookup (XEXP (loc, 0),
+					get_address_mode (loc), 0,
+					GET_MODE (loc));
+      if (addr)
+	return replace_equiv_address_nv (loc, addr->val_rtx);
+      else
+	return NULL;
+    }
+  else
+    return cselib_subst_to_values (loc, VOIDmode);
+}
+
+/* Return true if *X is a DEBUG_EXPR.  Usable as an argument to
+   for_each_rtx to tell whether there are any DEBUG_EXPRs within
+   RTX.  */
+
+static int
+rtx_debug_expr_p (rtx *x, void *data ATTRIBUTE_UNUSED)
+{
+  rtx loc = *x;
+
+  return GET_CODE (loc) == DEBUG_EXPR;
+}
+
+/* Determine what kind of micro operation to choose for a USE.  Return
+   MO_CLOBBER if no micro operation is to be generated.  */
+
+static enum micro_operation_type
+use_type (rtx loc, struct count_use_info *cui, enum machine_mode *modep)
+{
+  tree expr;
+
+  if (cui && cui->sets)
+    {
+      if (GET_CODE (loc) == VAR_LOCATION)
+	{
+	  if (track_expr_p (PAT_VAR_LOCATION_DECL (loc), false))
+	    {
+	      rtx ploc = PAT_VAR_LOCATION_LOC (loc);
+	      if (! VAR_LOC_UNKNOWN_P (ploc))
+		{
+		  cselib_val *val = cselib_lookup (ploc, GET_MODE (loc), 1,
+						   VOIDmode);
+
+		  /* ??? flag_float_store and volatile mems are never
+		     given values, but we could in theory use them for
+		     locations.  */
+		  gcc_assert (val || 1);
+		}
+	      return MO_VAL_LOC;
+	    }
+	  else
+	    return MO_CLOBBER;
+	}
+
+      if (REG_P (loc) || MEM_P (loc))
+	{
+	  if (modep)
+	    *modep = GET_MODE (loc);
+	  if (cui->store_p)
+	    {
+	      if (REG_P (loc)
+		  || (find_use_val (loc, GET_MODE (loc), cui)
+		      && cselib_lookup (XEXP (loc, 0),
+					get_address_mode (loc), 0,
+					GET_MODE (loc))))
+		return MO_VAL_SET;
+	    }
+	  else
+	    {
+	      cselib_val *val = find_use_val (loc, GET_MODE (loc), cui);
+
+	      if (val && !cselib_preserved_value_p (val))
+		return MO_VAL_USE;
+	    }
+	}
+    }
+
+  if (REG_P (loc))
+    {
+      gcc_assert (REGNO (loc) < FIRST_PSEUDO_REGISTER);
+
+      if (loc == cfa_base_rtx)
+	return MO_CLOBBER;
+      expr = REG_EXPR (loc);
+
+      if (!expr)
+	return MO_USE_NO_VAR;
+      else if (target_for_debug_bind (var_debug_decl (expr)))
+	return MO_CLOBBER;
+      else if (track_loc_p (loc, expr, REG_OFFSET (loc),
+			    false, modep, NULL))
+	return MO_USE;
+      else
+	return MO_USE_NO_VAR;
+    }
+  else if (MEM_P (loc))
+    {
+      expr = MEM_EXPR (loc);
+
+      if (!expr)
+	return MO_CLOBBER;
+      else if (target_for_debug_bind (var_debug_decl (expr)))
+	return MO_CLOBBER;
+      else if (track_loc_p (loc, expr, INT_MEM_OFFSET (loc),
+			    false, modep, NULL)
+	       /* Multi-part variables shouldn't refer to one-part
+		  variable names such as VALUEs (never happens) or
+		  DEBUG_EXPRs (only happens in the presence of debug
+		  insns).  */
+	       && (!MAY_HAVE_DEBUG_INSNS
+		   || !for_each_rtx (&XEXP (loc, 0), rtx_debug_expr_p, NULL)))
+	return MO_USE;
+      else
+	return MO_CLOBBER;
+    }
+
+  return MO_CLOBBER;
+}
+
+/* Log to OUT information about micro-operation MOPT involving X in
+   INSN of BB.  */
+
+static inline void
+log_op_type (rtx x, basic_block bb, rtx insn,
+	     enum micro_operation_type mopt, FILE *out)
+{
+  fprintf (out, "bb %i op %i insn %i %s ",
+	   bb->index, VTI (bb)->mos.length (),
+	   INSN_UID (insn), micro_operation_type_name[mopt]);
+  print_inline_rtx (out, x, 2);
+  fputc ('\n', out);
+}
+
+/* Tell whether the CONCAT used to holds a VALUE and its location
+   needs value resolution, i.e., an attempt of mapping the location
+   back to other incoming values.  */
+#define VAL_NEEDS_RESOLUTION(x) \
+  (RTL_FLAG_CHECK1 ("VAL_NEEDS_RESOLUTION", (x), CONCAT)->volatil)
+/* Whether the location in the CONCAT is a tracked expression, that
+   should also be handled like a MO_USE.  */
+#define VAL_HOLDS_TRACK_EXPR(x) \
+  (RTL_FLAG_CHECK1 ("VAL_HOLDS_TRACK_EXPR", (x), CONCAT)->used)
+/* Whether the location in the CONCAT should be handled like a MO_COPY
+   as well.  */
+#define VAL_EXPR_IS_COPIED(x) \
+  (RTL_FLAG_CHECK1 ("VAL_EXPR_IS_COPIED", (x), CONCAT)->jump)
+/* Whether the location in the CONCAT should be handled like a
+   MO_CLOBBER as well.  */
+#define VAL_EXPR_IS_CLOBBERED(x) \
+  (RTL_FLAG_CHECK1 ("VAL_EXPR_IS_CLOBBERED", (x), CONCAT)->unchanging)
+
+/* All preserved VALUEs.  */
+static vec<rtx> preserved_values;
+
+/* Ensure VAL is preserved and remember it in a vector for vt_emit_notes.  */
+
+static void
+preserve_value (cselib_val *val)
+{
+  cselib_preserve_value (val);
+  preserved_values.safe_push (val->val_rtx);
+}
+
+/* Helper function for MO_VAL_LOC handling.  Return non-zero if
+   any rtxes not suitable for CONST use not replaced by VALUEs
+   are discovered.  */
+
+static int
+non_suitable_const (rtx *x, void *data ATTRIBUTE_UNUSED)
+{
+  if (*x == NULL_RTX)
+    return 0;
+
+  switch (GET_CODE (*x))
+    {
+    case REG:
+    case DEBUG_EXPR:
+    case PC:
+    case SCRATCH:
+    case CC0:
+    case ASM_INPUT:
+    case ASM_OPERANDS:
+      return 1;
+    case MEM:
+      return !MEM_READONLY_P (*x);
+    default:
+      return 0;
+    }
+}
+
+/* Add uses (register and memory references) LOC which will be tracked
+   to VTI (bb)->mos.  INSN is instruction which the LOC is part of.  */
+
+static int
+add_uses (rtx *ploc, void *data)
+{
+  rtx loc = *ploc;
+  enum machine_mode mode = VOIDmode;
+  struct count_use_info *cui = (struct count_use_info *)data;
+  enum micro_operation_type type = use_type (loc, cui, &mode);
+
+  if (type != MO_CLOBBER)
+    {
+      basic_block bb = cui->bb;
+      micro_operation mo;
+
+      mo.type = type;
+      mo.u.loc = type == MO_USE ? var_lowpart (mode, loc) : loc;
+      mo.insn = cui->insn;
+
+      if (type == MO_VAL_LOC)
+	{
+	  rtx oloc = loc;
+	  rtx vloc = PAT_VAR_LOCATION_LOC (oloc);
+	  cselib_val *val;
+
+	  gcc_assert (cui->sets);
+
+	  if (MEM_P (vloc)
+	      && !REG_P (XEXP (vloc, 0))
+	      && !MEM_P (XEXP (vloc, 0)))
+	    {
+	      rtx mloc = vloc;
+	      enum machine_mode address_mode = get_address_mode (mloc);
+	      cselib_val *val
+		= cselib_lookup (XEXP (mloc, 0), address_mode, 0,
+				 GET_MODE (mloc));
+
+	      if (val && !cselib_preserved_value_p (val))
+		preserve_value (val);
+	    }
+
+	  if (CONSTANT_P (vloc)
+	      && (GET_CODE (vloc) != CONST
+		  || for_each_rtx (&vloc, non_suitable_const, NULL)))
+	    /* For constants don't look up any value.  */;
+	  else if (!VAR_LOC_UNKNOWN_P (vloc) && !unsuitable_loc (vloc)
+		   && (val = find_use_val (vloc, GET_MODE (oloc), cui)))
+	    {
+	      enum machine_mode mode2;
+	      enum micro_operation_type type2;
+	      rtx nloc = NULL;
+	      bool resolvable = REG_P (vloc) || MEM_P (vloc);
+
+	      if (resolvable)
+		nloc = replace_expr_with_values (vloc);
+
+	      if (nloc)
+		{
+		  oloc = shallow_copy_rtx (oloc);
+		  PAT_VAR_LOCATION_LOC (oloc) = nloc;
+		}
+
+	      oloc = gen_rtx_CONCAT (mode, val->val_rtx, oloc);
+
+	      type2 = use_type (vloc, 0, &mode2);
+
+	      gcc_assert (type2 == MO_USE || type2 == MO_USE_NO_VAR
+			  || type2 == MO_CLOBBER);
+
+	      if (type2 == MO_CLOBBER
+		  && !cselib_preserved_value_p (val))
+		{
+		  VAL_NEEDS_RESOLUTION (oloc) = resolvable;
+		  preserve_value (val);
+		}
+	    }
+	  else if (!VAR_LOC_UNKNOWN_P (vloc))
+	    {
+	      oloc = shallow_copy_rtx (oloc);
+	      PAT_VAR_LOCATION_LOC (oloc) = gen_rtx_UNKNOWN_VAR_LOC ();
+	    }
+
+	  mo.u.loc = oloc;
+	}
+      else if (type == MO_VAL_USE)
+	{
+	  enum machine_mode mode2 = VOIDmode;
+	  enum micro_operation_type type2;
+	  cselib_val *val = find_use_val (loc, GET_MODE (loc), cui);
+	  rtx vloc, oloc = loc, nloc;
+
+	  gcc_assert (cui->sets);
+
+	  if (MEM_P (oloc)
+	      && !REG_P (XEXP (oloc, 0))
+	      && !MEM_P (XEXP (oloc, 0)))
+	    {
+	      rtx mloc = oloc;
+	      enum machine_mode address_mode = get_address_mode (mloc);
+	      cselib_val *val
+		= cselib_lookup (XEXP (mloc, 0), address_mode, 0,
+				 GET_MODE (mloc));
+
+	      if (val && !cselib_preserved_value_p (val))
+		preserve_value (val);
+	    }
+
+	  type2 = use_type (loc, 0, &mode2);
+
+	  gcc_assert (type2 == MO_USE || type2 == MO_USE_NO_VAR
+		      || type2 == MO_CLOBBER);
+
+	  if (type2 == MO_USE)
+	    vloc = var_lowpart (mode2, loc);
+	  else
+	    vloc = oloc;
+
+	  /* The loc of a MO_VAL_USE may have two forms:
+
+	     (concat val src): val is at src, a value-based
+	     representation.
+
+	     (concat (concat val use) src): same as above, with use as
+	     the MO_USE tracked value, if it differs from src.
+
+	  */
+
+	  gcc_checking_assert (REG_P (loc) || MEM_P (loc));
+	  nloc = replace_expr_with_values (loc);
+	  if (!nloc)
+	    nloc = oloc;
+
+	  if (vloc != nloc)
+	    oloc = gen_rtx_CONCAT (mode2, val->val_rtx, vloc);
+	  else
+	    oloc = val->val_rtx;
+
+	  mo.u.loc = gen_rtx_CONCAT (mode, oloc, nloc);
+
+	  if (type2 == MO_USE)
+	    VAL_HOLDS_TRACK_EXPR (mo.u.loc) = 1;
+	  if (!cselib_preserved_value_p (val))
+	    {
+	      VAL_NEEDS_RESOLUTION (mo.u.loc) = 1;
+	      preserve_value (val);
+	    }
+	}
+      else
+	gcc_assert (type == MO_USE || type == MO_USE_NO_VAR);
+
+      if (dump_file && (dump_flags & TDF_DETAILS))
+	log_op_type (mo.u.loc, cui->bb, cui->insn, mo.type, dump_file);
+      VTI (bb)->mos.safe_push (mo);
+    }
+
+  return 0;
+}
+
+/* Helper function for finding all uses of REG/MEM in X in insn INSN.  */
+
+static void
+add_uses_1 (rtx *x, void *cui)
+{
+  for_each_rtx (x, add_uses, cui);
+}
+
+/* This is the value used during expansion of locations.  We want it
+   to be unbounded, so that variables expanded deep in a recursion
+   nest are fully evaluated, so that their values are cached
+   correctly.  We avoid recursion cycles through other means, and we
+   don't unshare RTL, so excess complexity is not a problem.  */
+#define EXPR_DEPTH (INT_MAX)
+/* We use this to keep too-complex expressions from being emitted as
+   location notes, and then to debug information.  Users can trade
+   compile time for ridiculously complex expressions, although they're
+   seldom useful, and they may often have to be discarded as not
+   representable anyway.  */
+#define EXPR_USE_DEPTH (PARAM_VALUE (PARAM_MAX_VARTRACK_EXPR_DEPTH))
+
+/* Attempt to reverse the EXPR operation in the debug info and record
+   it in the cselib table.  Say for reg1 = reg2 + 6 even when reg2 is
+   no longer live we can express its value as VAL - 6.  */
+
+static void
+reverse_op (rtx val, const_rtx expr, rtx insn)
+{
+  rtx src, arg, ret;
+  cselib_val *v;
+  struct elt_loc_list *l;
+  enum rtx_code code;
+  int count;
+
+  if (GET_CODE (expr) != SET)
+    return;
+
+  if (!REG_P (SET_DEST (expr)) || GET_MODE (val) != GET_MODE (SET_DEST (expr)))
+    return;
+
+  src = SET_SRC (expr);
+  switch (GET_CODE (src))
+    {
+    case PLUS:
+    case MINUS:
+    case XOR:
+    case NOT:
+    case NEG:
+      if (!REG_P (XEXP (src, 0)))
+	return;
+      break;
+    case SIGN_EXTEND:
+    case ZERO_EXTEND:
+      if (!REG_P (XEXP (src, 0)) && !MEM_P (XEXP (src, 0)))
+	return;
+      break;
+    default:
+      return;
+    }
+
+  if (!SCALAR_INT_MODE_P (GET_MODE (src)) || XEXP (src, 0) == cfa_base_rtx)
+    return;
+
+  v = cselib_lookup (XEXP (src, 0), GET_MODE (XEXP (src, 0)), 0, VOIDmode);
+  if (!v || !cselib_preserved_value_p (v))
+    return;
+
+  /* Use canonical V to avoid creating multiple redundant expressions
+     for different VALUES equivalent to V.  */
+  v = canonical_cselib_val (v);
+
+  /* Adding a reverse op isn't useful if V already has an always valid
+     location.  Ignore ENTRY_VALUE, while it is always constant, we should
+     prefer non-ENTRY_VALUE locations whenever possible.  */
+  for (l = v->locs, count = 0; l; l = l->next, count++)
+    if (CONSTANT_P (l->loc)
+	&& (GET_CODE (l->loc) != CONST || !references_value_p (l->loc, 0)))
+      return;
+    /* Avoid creating too large locs lists.  */
+    else if (count == PARAM_VALUE (PARAM_MAX_VARTRACK_REVERSE_OP_SIZE))
+      return;
+
+  switch (GET_CODE (src))
+    {
+    case NOT:
+    case NEG:
+      if (GET_MODE (v->val_rtx) != GET_MODE (val))
+	return;
+      ret = gen_rtx_fmt_e (GET_CODE (src), GET_MODE (val), val);
+      break;
+    case SIGN_EXTEND:
+    case ZERO_EXTEND:
+      ret = gen_lowpart_SUBREG (GET_MODE (v->val_rtx), val);
+      break;
+    case XOR:
+      code = XOR;
+      goto binary;
+    case PLUS:
+      code = MINUS;
+      goto binary;
+    case MINUS:
+      code = PLUS;
+      goto binary;
+    binary:
+      if (GET_MODE (v->val_rtx) != GET_MODE (val))
+	return;
+      arg = XEXP (src, 1);
+      if (!CONST_INT_P (arg) && GET_CODE (arg) != SYMBOL_REF)
+	{
+	  arg = cselib_expand_value_rtx (arg, scratch_regs, 5);
+	  if (arg == NULL_RTX)
+	    return;
+	  if (!CONST_INT_P (arg) && GET_CODE (arg) != SYMBOL_REF)
+	    return;
+	}
+      ret = simplify_gen_binary (code, GET_MODE (val), val, arg);
+      if (ret == val)
+	/* Ensure ret isn't VALUE itself (which can happen e.g. for
+	   (plus (reg1) (reg2)) when reg2 is known to be 0), as that
+	   breaks a lot of routines during var-tracking.  */
+	ret = gen_rtx_fmt_ee (PLUS, GET_MODE (val), val, const0_rtx);
+      break;
+    default:
+      gcc_unreachable ();
+    }
+
+  cselib_add_permanent_equiv (v, ret, insn);
+}
+
+/* Add stores (register and memory references) LOC which will be tracked
+   to VTI (bb)->mos.  EXPR is the RTL expression containing the store.
+   CUIP->insn is instruction which the LOC is part of.  */
+
+static void
+add_stores (rtx loc, const_rtx expr, void *cuip)
+{
+  enum machine_mode mode = VOIDmode, mode2;
+  struct count_use_info *cui = (struct count_use_info *)cuip;
+  basic_block bb = cui->bb;
+  micro_operation mo;
+  rtx oloc = loc, nloc, src = NULL;
+  enum micro_operation_type type = use_type (loc, cui, &mode);
+  bool track_p = false;
+  cselib_val *v;
+  bool resolve, preserve;
+
+  if (type == MO_CLOBBER)
+    return;
+
+  mode2 = mode;
+
+  if (REG_P (loc))
+    {
+      gcc_assert (loc != cfa_base_rtx);
+      if ((GET_CODE (expr) == CLOBBER && type != MO_VAL_SET)
+	  || !(track_p = use_type (loc, NULL, &mode2) == MO_USE)
+	  || GET_CODE (expr) == CLOBBER)
+	{
+	  mo.type = MO_CLOBBER;
+	  mo.u.loc = loc;
+	  if (GET_CODE (expr) == SET
+	      && SET_DEST (expr) == loc
+	      && !unsuitable_loc (SET_SRC (expr))
+	      && find_use_val (loc, mode, cui))
+	    {
+	      gcc_checking_assert (type == MO_VAL_SET);
+	      mo.u.loc = gen_rtx_SET (VOIDmode, loc, SET_SRC (expr));
+	    }
+	}
+      else
+	{
+	  if (GET_CODE (expr) == SET
+	      && SET_DEST (expr) == loc
+	      && GET_CODE (SET_SRC (expr)) != ASM_OPERANDS)
+	    src = var_lowpart (mode2, SET_SRC (expr));
+	  loc = var_lowpart (mode2, loc);
+
+	  if (src == NULL)
+	    {
+	      mo.type = MO_SET;
+	      mo.u.loc = loc;
+	    }
+	  else
+	    {
+	      rtx xexpr = gen_rtx_SET (VOIDmode, loc, src);
+	      if (same_variable_part_p (src, REG_EXPR (loc), REG_OFFSET (loc)))
+		{
+		  /* If this is an instruction copying (part of) a parameter
+		     passed by invisible reference to its register location,
+		     pretend it's a SET so that the initial memory location
+		     is discarded, as the parameter register can be reused
+		     for other purposes and we do not track locations based
+		     on generic registers.  */
+		  if (MEM_P (src)
+		      && REG_EXPR (loc)
+		      && TREE_CODE (REG_EXPR (loc)) == PARM_DECL
+		      && DECL_MODE (REG_EXPR (loc)) != BLKmode
+		      && MEM_P (DECL_INCOMING_RTL (REG_EXPR (loc)))
+		      && XEXP (DECL_INCOMING_RTL (REG_EXPR (loc)), 0)
+			 != arg_pointer_rtx)
+		    mo.type = MO_SET;
+		  else
+		    mo.type = MO_COPY;
+		}
+	      else
+		mo.type = MO_SET;
+	      mo.u.loc = xexpr;
+	    }
+	}
+      mo.insn = cui->insn;
+    }
+  else if (MEM_P (loc)
+	   && ((track_p = use_type (loc, NULL, &mode2) == MO_USE)
+	       || cui->sets))
+    {
+      if (MEM_P (loc) && type == MO_VAL_SET
+	  && !REG_P (XEXP (loc, 0))
+	  && !MEM_P (XEXP (loc, 0)))
+	{
+	  rtx mloc = loc;
+	  enum machine_mode address_mode = get_address_mode (mloc);
+	  cselib_val *val = cselib_lookup (XEXP (mloc, 0),
+					   address_mode, 0,
+					   GET_MODE (mloc));
+
+	  if (val && !cselib_preserved_value_p (val))
+	    preserve_value (val);
+	}
+
+      if (GET_CODE (expr) == CLOBBER || !track_p)
+	{
+	  mo.type = MO_CLOBBER;
+	  mo.u.loc = track_p ? var_lowpart (mode2, loc) : loc;
+	}
+      else
+	{
+	  if (GET_CODE (expr) == SET
+	      && SET_DEST (expr) == loc
+	      && GET_CODE (SET_SRC (expr)) != ASM_OPERANDS)
+	    src = var_lowpart (mode2, SET_SRC (expr));
+	  loc = var_lowpart (mode2, loc);
+
+	  if (src == NULL)
+	    {
+	      mo.type = MO_SET;
+	      mo.u.loc = loc;
+	    }
+	  else
+	    {
+	      rtx xexpr = gen_rtx_SET (VOIDmode, loc, src);
+	      if (same_variable_part_p (SET_SRC (xexpr),
+					MEM_EXPR (loc),
+					INT_MEM_OFFSET (loc)))
+		mo.type = MO_COPY;
+	      else
+		mo.type = MO_SET;
+	      mo.u.loc = xexpr;
+	    }
+	}
+      mo.insn = cui->insn;
+    }
+  else
+    return;
+
+  if (type != MO_VAL_SET)
+    goto log_and_return;
+
+  v = find_use_val (oloc, mode, cui);
+
+  if (!v)
+    goto log_and_return;
+
+  resolve = preserve = !cselib_preserved_value_p (v);
+
+  /* We cannot track values for multiple-part variables, so we track only
+     locations for tracked parameters passed either by invisible reference
+     or directly in multiple locations.  */
+  if (track_p
+      && REG_P (loc)
+      && REG_EXPR (loc)
+      && TREE_CODE (REG_EXPR (loc)) == PARM_DECL
+      && DECL_MODE (REG_EXPR (loc)) != BLKmode
+      && TREE_CODE (TREE_TYPE (REG_EXPR (loc))) != UNION_TYPE
+      && ((MEM_P (DECL_INCOMING_RTL (REG_EXPR (loc)))
+	   && XEXP (DECL_INCOMING_RTL (REG_EXPR (loc)), 0) != arg_pointer_rtx)
+          || (GET_CODE (DECL_INCOMING_RTL (REG_EXPR (loc))) == PARALLEL
+	      && XVECLEN (DECL_INCOMING_RTL (REG_EXPR (loc)), 0) > 1)))
+    {
+      /* Although we don't use the value here, it could be used later by the
+	 mere virtue of its existence as the operand of the reverse operation
+	 that gave rise to it (typically extension/truncation).  Make sure it
+	 is preserved as required by vt_expand_var_loc_chain.  */
+      if (preserve)
+	preserve_value (v);
+      goto log_and_return;
+    }
+
+  if (loc == stack_pointer_rtx
+      && hard_frame_pointer_adjustment != -1
+      && preserve)
+    cselib_set_value_sp_based (v);
+
+  nloc = replace_expr_with_values (oloc);
+  if (nloc)
+    oloc = nloc;
+
+  if (GET_CODE (PATTERN (cui->insn)) == COND_EXEC)
+    {
+      cselib_val *oval = cselib_lookup (oloc, GET_MODE (oloc), 0, VOIDmode);
+
+      gcc_assert (oval != v);
+      gcc_assert (REG_P (oloc) || MEM_P (oloc));
+
+      if (oval && !cselib_preserved_value_p (oval))
+	{
+	  micro_operation moa;
+
+	  preserve_value (oval);
+
+	  moa.type = MO_VAL_USE;
+	  moa.u.loc = gen_rtx_CONCAT (mode, oval->val_rtx, oloc);
+	  VAL_NEEDS_RESOLUTION (moa.u.loc) = 1;
+	  moa.insn = cui->insn;
+
+	  if (dump_file && (dump_flags & TDF_DETAILS))
+	    log_op_type (moa.u.loc, cui->bb, cui->insn,
+			 moa.type, dump_file);
+	  VTI (bb)->mos.safe_push (moa);
+	}
+
+      resolve = false;
+    }
+  else if (resolve && GET_CODE (mo.u.loc) == SET)
+    {
+      if (REG_P (SET_SRC (expr)) || MEM_P (SET_SRC (expr)))
+	nloc = replace_expr_with_values (SET_SRC (expr));
+      else
+	nloc = NULL_RTX;
+
+      /* Avoid the mode mismatch between oexpr and expr.  */
+      if (!nloc && mode != mode2)
+	{
+	  nloc = SET_SRC (expr);
+	  gcc_assert (oloc == SET_DEST (expr));
+	}
+
+      if (nloc && nloc != SET_SRC (mo.u.loc))
+	oloc = gen_rtx_SET (GET_MODE (mo.u.loc), oloc, nloc);
+      else
+	{
+	  if (oloc == SET_DEST (mo.u.loc))
+	    /* No point in duplicating.  */
+	    oloc = mo.u.loc;
+	  if (!REG_P (SET_SRC (mo.u.loc)))
+	    resolve = false;
+	}
+    }
+  else if (!resolve)
+    {
+      if (GET_CODE (mo.u.loc) == SET
+	  && oloc == SET_DEST (mo.u.loc))
+	/* No point in duplicating.  */
+	oloc = mo.u.loc;
+    }
+  else
+    resolve = false;
+
+  loc = gen_rtx_CONCAT (mode, v->val_rtx, oloc);
+
+  if (mo.u.loc != oloc)
+    loc = gen_rtx_CONCAT (GET_MODE (mo.u.loc), loc, mo.u.loc);
+
+  /* The loc of a MO_VAL_SET may have various forms:
+
+     (concat val dst): dst now holds val
+
+     (concat val (set dst src)): dst now holds val, copied from src
+
+     (concat (concat val dstv) dst): dst now holds val; dstv is dst
+     after replacing mems and non-top-level regs with values.
+
+     (concat (concat val dstv) (set dst src)): dst now holds val,
+     copied from src.  dstv is a value-based representation of dst, if
+     it differs from dst.  If resolution is needed, src is a REG, and
+     its mode is the same as that of val.
+
+     (concat (concat val (set dstv srcv)) (set dst src)): src
+     copied to dst, holding val.  dstv and srcv are value-based
+     representations of dst and src, respectively.
+
+  */
+
+  if (GET_CODE (PATTERN (cui->insn)) != COND_EXEC)
+    reverse_op (v->val_rtx, expr, cui->insn);
+
+  mo.u.loc = loc;
+
+  if (track_p)
+    VAL_HOLDS_TRACK_EXPR (loc) = 1;
+  if (preserve)
+    {
+      VAL_NEEDS_RESOLUTION (loc) = resolve;
+      preserve_value (v);
+    }
+  if (mo.type == MO_CLOBBER)
+    VAL_EXPR_IS_CLOBBERED (loc) = 1;
+  if (mo.type == MO_COPY)
+    VAL_EXPR_IS_COPIED (loc) = 1;
+
+  mo.type = MO_VAL_SET;
+
+ log_and_return:
+  if (dump_file && (dump_flags & TDF_DETAILS))
+    log_op_type (mo.u.loc, cui->bb, cui->insn, mo.type, dump_file);
+  VTI (bb)->mos.safe_push (mo);
+}
+
+/* Arguments to the call.  */
+static rtx call_arguments;
+
+/* Compute call_arguments.  */
+
+static void
+prepare_call_arguments (basic_block bb, rtx insn)
+{
+  rtx link, x, call;
+  rtx prev, cur, next;
+  rtx this_arg = NULL_RTX;
+  tree type = NULL_TREE, t, fndecl = NULL_TREE;
+  tree obj_type_ref = NULL_TREE;
+  CUMULATIVE_ARGS args_so_far_v;
+  cumulative_args_t args_so_far;
+
+  memset (&args_so_far_v, 0, sizeof (args_so_far_v));
+  args_so_far = pack_cumulative_args (&args_so_far_v);
+  call = get_call_rtx_from (insn);
+  if (call)
+    {
+      if (GET_CODE (XEXP (XEXP (call, 0), 0)) == SYMBOL_REF)
+	{
+	  rtx symbol = XEXP (XEXP (call, 0), 0);
+	  if (SYMBOL_REF_DECL (symbol))
+	    fndecl = SYMBOL_REF_DECL (symbol);
+	}
+      if (fndecl == NULL_TREE)
+	fndecl = MEM_EXPR (XEXP (call, 0));
+      if (fndecl
+	  && TREE_CODE (TREE_TYPE (fndecl)) != FUNCTION_TYPE
+	  && TREE_CODE (TREE_TYPE (fndecl)) != METHOD_TYPE)
+	fndecl = NULL_TREE;
+      if (fndecl && TYPE_ARG_TYPES (TREE_TYPE (fndecl)))
+	type = TREE_TYPE (fndecl);
+      if (fndecl && TREE_CODE (fndecl) != FUNCTION_DECL)
+	{
+	  if (TREE_CODE (fndecl) == INDIRECT_REF
+	      && TREE_CODE (TREE_OPERAND (fndecl, 0)) == OBJ_TYPE_REF)
+	    obj_type_ref = TREE_OPERAND (fndecl, 0);
+	  fndecl = NULL_TREE;
+	}
+      if (type)
+	{
+	  for (t = TYPE_ARG_TYPES (type); t && t != void_list_node;
+	       t = TREE_CHAIN (t))
+	    if (TREE_CODE (TREE_VALUE (t)) == REFERENCE_TYPE
+		&& INTEGRAL_TYPE_P (TREE_TYPE (TREE_VALUE (t))))
+	      break;
+	  if ((t == NULL || t == void_list_node) && obj_type_ref == NULL_TREE)
+	    type = NULL;
+	  else
+	    {
+	      int nargs ATTRIBUTE_UNUSED = list_length (TYPE_ARG_TYPES (type));
+	      link = CALL_INSN_FUNCTION_USAGE (insn);
+#ifndef PCC_STATIC_STRUCT_RETURN
+	      if (aggregate_value_p (TREE_TYPE (type), type)
+		  && targetm.calls.struct_value_rtx (type, 0) == 0)
+		{
+		  tree struct_addr = build_pointer_type (TREE_TYPE (type));
+		  enum machine_mode mode = TYPE_MODE (struct_addr);
+		  rtx reg;
+		  INIT_CUMULATIVE_ARGS (args_so_far_v, type, NULL_RTX, fndecl,
+					nargs + 1);
+		  reg = targetm.calls.function_arg (args_so_far, mode,
+						    struct_addr, true);
+		  targetm.calls.function_arg_advance (args_so_far, mode,
+						      struct_addr, true);
+		  if (reg == NULL_RTX)
+		    {
+		      for (; link; link = XEXP (link, 1))
+			if (GET_CODE (XEXP (link, 0)) == USE
+			    && MEM_P (XEXP (XEXP (link, 0), 0)))
+			  {
+			    link = XEXP (link, 1);
+			    break;
+			  }
+		    }
+		}
+	      else
+#endif
+		INIT_CUMULATIVE_ARGS (args_so_far_v, type, NULL_RTX, fndecl,
+				      nargs);
+	      if (obj_type_ref && TYPE_ARG_TYPES (type) != void_list_node)
+		{
+		  enum machine_mode mode;
+		  t = TYPE_ARG_TYPES (type);
+		  mode = TYPE_MODE (TREE_VALUE (t));
+		  this_arg = targetm.calls.function_arg (args_so_far, mode,
+							 TREE_VALUE (t), true);
+		  if (this_arg && !REG_P (this_arg))
+		    this_arg = NULL_RTX;
+		  else if (this_arg == NULL_RTX)
+		    {
+		      for (; link; link = XEXP (link, 1))
+			if (GET_CODE (XEXP (link, 0)) == USE
+			    && MEM_P (XEXP (XEXP (link, 0), 0)))
+			  {
+			    this_arg = XEXP (XEXP (link, 0), 0);
+			    break;
+			  }
+		    }
+		}
+	    }
+	}
+    }
+  t = type ? TYPE_ARG_TYPES (type) : NULL_TREE;
+
+  for (link = CALL_INSN_FUNCTION_USAGE (insn); link; link = XEXP (link, 1))
+    if (GET_CODE (XEXP (link, 0)) == USE)
+      {
+	rtx item = NULL_RTX;
+	x = XEXP (XEXP (link, 0), 0);
+	if (GET_MODE (link) == VOIDmode
+	    || GET_MODE (link) == BLKmode
+	    || (GET_MODE (link) != GET_MODE (x)
+		&& (GET_MODE_CLASS (GET_MODE (link)) != MODE_INT
+		    || GET_MODE_CLASS (GET_MODE (x)) != MODE_INT)))
+	  /* Can't do anything for these, if the original type mode
+	     isn't known or can't be converted.  */;
+	else if (REG_P (x))
+	  {
+	    cselib_val *val = cselib_lookup (x, GET_MODE (x), 0, VOIDmode);
+	    if (val && cselib_preserved_value_p (val))
+	      item = val->val_rtx;
+	    else if (GET_MODE_CLASS (GET_MODE (x)) == MODE_INT)
+	      {
+		enum machine_mode mode = GET_MODE (x);
+
+		while ((mode = GET_MODE_WIDER_MODE (mode)) != VOIDmode
+		       && GET_MODE_BITSIZE (mode) <= BITS_PER_WORD)
+		  {
+		    rtx reg = simplify_subreg (mode, x, GET_MODE (x), 0);
+
+		    if (reg == NULL_RTX || !REG_P (reg))
+		      continue;
+		    val = cselib_lookup (reg, mode, 0, VOIDmode);
+		    if (val && cselib_preserved_value_p (val))
+		      {
+			item = val->val_rtx;
+			break;
+		      }
+		  }
+	      }
+	  }
+	else if (MEM_P (x))
+	  {
+	    rtx mem = x;
+	    cselib_val *val;
+
+	    if (!frame_pointer_needed)
+	      {
+		struct adjust_mem_data amd;
+		amd.mem_mode = VOIDmode;
+		amd.stack_adjust = -VTI (bb)->out.stack_adjust;
+		amd.side_effects = NULL_RTX;
+		amd.store = true;
+		mem = simplify_replace_fn_rtx (mem, NULL_RTX, adjust_mems,
+					       &amd);
+		gcc_assert (amd.side_effects == NULL_RTX);
+	      }
+	    val = cselib_lookup (mem, GET_MODE (mem), 0, VOIDmode);
+	    if (val && cselib_preserved_value_p (val))
+	      item = val->val_rtx;
+	    else if (GET_MODE_CLASS (GET_MODE (mem)) != MODE_INT)
+	      {
+		/* For non-integer stack argument see also if they weren't
+		   initialized by integers.  */
+		enum machine_mode imode = int_mode_for_mode (GET_MODE (mem));
+		if (imode != GET_MODE (mem) && imode != BLKmode)
+		  {
+		    val = cselib_lookup (adjust_address_nv (mem, imode, 0),
+					 imode, 0, VOIDmode);
+		    if (val && cselib_preserved_value_p (val))
+		      item = lowpart_subreg (GET_MODE (x), val->val_rtx,
+					     imode);
+		  }
+	      }
+	  }
+	if (item)
+	  {
+	    rtx x2 = x;
+	    if (GET_MODE (item) != GET_MODE (link))
+	      item = lowpart_subreg (GET_MODE (link), item, GET_MODE (item));
+	    if (GET_MODE (x2) != GET_MODE (link))
+	      x2 = lowpart_subreg (GET_MODE (link), x2, GET_MODE (x2));
+	    item = gen_rtx_CONCAT (GET_MODE (link), x2, item);
+	    call_arguments
+	      = gen_rtx_EXPR_LIST (VOIDmode, item, call_arguments);
+	  }
+	if (t && t != void_list_node)
+	  {
+	    tree argtype = TREE_VALUE (t);
+	    enum machine_mode mode = TYPE_MODE (argtype);
+	    rtx reg;
+	    if (pass_by_reference (&args_so_far_v, mode, argtype, true))
+	      {
+		argtype = build_pointer_type (argtype);
+		mode = TYPE_MODE (argtype);
+	      }
+	    reg = targetm.calls.function_arg (args_so_far, mode,
+					      argtype, true);
+	    if (TREE_CODE (argtype) == REFERENCE_TYPE
+		&& INTEGRAL_TYPE_P (TREE_TYPE (argtype))
+		&& reg
+		&& REG_P (reg)
+		&& GET_MODE (reg) == mode
+		&& GET_MODE_CLASS (mode) == MODE_INT
+		&& REG_P (x)
+		&& REGNO (x) == REGNO (reg)
+		&& GET_MODE (x) == mode
+		&& item)
+	      {
+		enum machine_mode indmode
+		  = TYPE_MODE (TREE_TYPE (argtype));
+		rtx mem = gen_rtx_MEM (indmode, x);
+		cselib_val *val = cselib_lookup (mem, indmode, 0, VOIDmode);
+		if (val && cselib_preserved_value_p (val))
+		  {
+		    item = gen_rtx_CONCAT (indmode, mem, val->val_rtx);
+		    call_arguments = gen_rtx_EXPR_LIST (VOIDmode, item,
+							call_arguments);
+		  }
+		else
+		  {
+		    struct elt_loc_list *l;
+		    tree initial;
+
+		    /* Try harder, when passing address of a constant
+		       pool integer it can be easily read back.  */
+		    item = XEXP (item, 1);
+		    if (GET_CODE (item) == SUBREG)
+		      item = SUBREG_REG (item);
+		    gcc_assert (GET_CODE (item) == VALUE);
+		    val = CSELIB_VAL_PTR (item);
+		    for (l = val->locs; l; l = l->next)
+		      if (GET_CODE (l->loc) == SYMBOL_REF
+			  && TREE_CONSTANT_POOL_ADDRESS_P (l->loc)
+			  && SYMBOL_REF_DECL (l->loc)
+			  && DECL_INITIAL (SYMBOL_REF_DECL (l->loc)))
+			{
+			  initial = DECL_INITIAL (SYMBOL_REF_DECL (l->loc));
+			  if (tree_fits_shwi_p (initial))
+			    {
+			      item = GEN_INT (tree_to_shwi (initial));
+			      item = gen_rtx_CONCAT (indmode, mem, item);
+			      call_arguments
+				= gen_rtx_EXPR_LIST (VOIDmode, item,
+						     call_arguments);
+			    }
+			  break;
+			}
+		  }
+	      }
+	    targetm.calls.function_arg_advance (args_so_far, mode,
+						argtype, true);
+	    t = TREE_CHAIN (t);
+	  }
+      }
+
+  /* Add debug arguments.  */
+  if (fndecl
+      && TREE_CODE (fndecl) == FUNCTION_DECL
+      && DECL_HAS_DEBUG_ARGS_P (fndecl))
+    {
+      vec<tree, va_gc> **debug_args = decl_debug_args_lookup (fndecl);
+      if (debug_args)
+	{
+	  unsigned int ix;
+	  tree param;
+	  for (ix = 0; vec_safe_iterate (*debug_args, ix, &param); ix += 2)
+	    {
+	      rtx item;
+	      tree dtemp = (**debug_args)[ix + 1];
+	      enum machine_mode mode = DECL_MODE (dtemp);
+	      item = gen_rtx_DEBUG_PARAMETER_REF (mode, param);
+	      item = gen_rtx_CONCAT (mode, item, DECL_RTL_KNOWN_SET (dtemp));
+	      call_arguments = gen_rtx_EXPR_LIST (VOIDmode, item,
+						  call_arguments);
+	    }
+	}
+    }
+
+  /* Reverse call_arguments chain.  */
+  prev = NULL_RTX;
+  for (cur = call_arguments; cur; cur = next)
+    {
+      next = XEXP (cur, 1);
+      XEXP (cur, 1) = prev;
+      prev = cur;
+    }
+  call_arguments = prev;
+
+  x = get_call_rtx_from (insn);
+  if (x)
+    {
+      x = XEXP (XEXP (x, 0), 0);
+      if (GET_CODE (x) == SYMBOL_REF)
+	/* Don't record anything.  */;
+      else if (CONSTANT_P (x))
+	{
+	  x = gen_rtx_CONCAT (GET_MODE (x) == VOIDmode ? Pmode : GET_MODE (x),
+			      pc_rtx, x);
+	  call_arguments
+	    = gen_rtx_EXPR_LIST (VOIDmode, x, call_arguments);
+	}
+      else
+	{
+	  cselib_val *val = cselib_lookup (x, GET_MODE (x), 0, VOIDmode);
+	  if (val && cselib_preserved_value_p (val))
+	    {
+	      x = gen_rtx_CONCAT (GET_MODE (x), pc_rtx, val->val_rtx);
+	      call_arguments
+		= gen_rtx_EXPR_LIST (VOIDmode, x, call_arguments);
+	    }
+	}
+    }
+  if (this_arg)
+    {
+      enum machine_mode mode
+	= TYPE_MODE (TREE_TYPE (OBJ_TYPE_REF_EXPR (obj_type_ref)));
+      rtx clobbered = gen_rtx_MEM (mode, this_arg);
+      HOST_WIDE_INT token
+	= tree_to_shwi (OBJ_TYPE_REF_TOKEN (obj_type_ref));
+      if (token)
+	clobbered = plus_constant (mode, clobbered,
+				   token * GET_MODE_SIZE (mode));
+      clobbered = gen_rtx_MEM (mode, clobbered);
+      x = gen_rtx_CONCAT (mode, gen_rtx_CLOBBER (VOIDmode, pc_rtx), clobbered);
+      call_arguments
+	= gen_rtx_EXPR_LIST (VOIDmode, x, call_arguments);
+    }
+}
+
+/* Callback for cselib_record_sets_hook, that records as micro
+   operations uses and stores in an insn after cselib_record_sets has
+   analyzed the sets in an insn, but before it modifies the stored
+   values in the internal tables, unless cselib_record_sets doesn't
+   call it directly (perhaps because we're not doing cselib in the
+   first place, in which case sets and n_sets will be 0).  */
+
+static void
+add_with_sets (rtx insn, struct cselib_set *sets, int n_sets)
+{
+  basic_block bb = BLOCK_FOR_INSN (insn);
+  int n1, n2;
+  struct count_use_info cui;
+  micro_operation *mos;
+
+  cselib_hook_called = true;
+
+  cui.insn = insn;
+  cui.bb = bb;
+  cui.sets = sets;
+  cui.n_sets = n_sets;
+
+  n1 = VTI (bb)->mos.length ();
+  cui.store_p = false;
+  note_uses (&PATTERN (insn), add_uses_1, &cui);
+  n2 = VTI (bb)->mos.length () - 1;
+  mos = VTI (bb)->mos.address ();
+
+  /* Order the MO_USEs to be before MO_USE_NO_VARs and MO_VAL_USE, and
+     MO_VAL_LOC last.  */
+  while (n1 < n2)
+    {
+      while (n1 < n2 && mos[n1].type == MO_USE)
+	n1++;
+      while (n1 < n2 && mos[n2].type != MO_USE)
+	n2--;
+      if (n1 < n2)
+	{
+	  micro_operation sw;
+
+	  sw = mos[n1];
+	  mos[n1] = mos[n2];
+	  mos[n2] = sw;
+	}
+    }
+
+  n2 = VTI (bb)->mos.length () - 1;
+  while (n1 < n2)
+    {
+      while (n1 < n2 && mos[n1].type != MO_VAL_LOC)
+	n1++;
+      while (n1 < n2 && mos[n2].type == MO_VAL_LOC)
+	n2--;
+      if (n1 < n2)
+	{
+	  micro_operation sw;
+
+	  sw = mos[n1];
+	  mos[n1] = mos[n2];
+	  mos[n2] = sw;
+	}
+    }
+
+  if (CALL_P (insn))
+    {
+      micro_operation mo;
+
+      mo.type = MO_CALL;
+      mo.insn = insn;
+      mo.u.loc = call_arguments;
+      call_arguments = NULL_RTX;
+
+      if (dump_file && (dump_flags & TDF_DETAILS))
+	log_op_type (PATTERN (insn), bb, insn, mo.type, dump_file);
+      VTI (bb)->mos.safe_push (mo);
+    }
+
+  n1 = VTI (bb)->mos.length ();
+  /* This will record NEXT_INSN (insn), such that we can
+     insert notes before it without worrying about any
+     notes that MO_USEs might emit after the insn.  */
+  cui.store_p = true;
+  note_stores (PATTERN (insn), add_stores, &cui);
+  n2 = VTI (bb)->mos.length () - 1;
+  mos = VTI (bb)->mos.address ();
+
+  /* Order the MO_VAL_USEs first (note_stores does nothing
+     on DEBUG_INSNs, so there are no MO_VAL_LOCs from this
+     insn), then MO_CLOBBERs, then MO_SET/MO_COPY/MO_VAL_SET.  */
+  while (n1 < n2)
+    {
+      while (n1 < n2 && mos[n1].type == MO_VAL_USE)
+	n1++;
+      while (n1 < n2 && mos[n2].type != MO_VAL_USE)
+	n2--;
+      if (n1 < n2)
+	{
+	  micro_operation sw;
+
+	  sw = mos[n1];
+	  mos[n1] = mos[n2];
+	  mos[n2] = sw;
+	}
+    }
+
+  n2 = VTI (bb)->mos.length () - 1;
+  while (n1 < n2)
+    {
+      while (n1 < n2 && mos[n1].type == MO_CLOBBER)
+	n1++;
+      while (n1 < n2 && mos[n2].type != MO_CLOBBER)
+	n2--;
+      if (n1 < n2)
+	{
+	  micro_operation sw;
+
+	  sw = mos[n1];
+	  mos[n1] = mos[n2];
+	  mos[n2] = sw;
+	}
+    }
+}
+
+static enum var_init_status
+find_src_status (dataflow_set *in, rtx src)
+{
+  tree decl = NULL_TREE;
+  enum var_init_status status = VAR_INIT_STATUS_UNINITIALIZED;
+
+  if (! flag_var_tracking_uninit)
+    status = VAR_INIT_STATUS_INITIALIZED;
+
+  if (src && REG_P (src))
+    decl = var_debug_decl (REG_EXPR (src));
+  else if (src && MEM_P (src))
+    decl = var_debug_decl (MEM_EXPR (src));
+
+  if (src && decl)
+    status = get_init_value (in, src, dv_from_decl (decl));
+
+  return status;
+}
+
+/* SRC is the source of an assignment.  Use SET to try to find what
+   was ultimately assigned to SRC.  Return that value if known,
+   otherwise return SRC itself.  */
+
+static rtx
+find_src_set_src (dataflow_set *set, rtx src)
+{
+  tree decl = NULL_TREE;   /* The variable being copied around.          */
+  rtx set_src = NULL_RTX;  /* The value for "decl" stored in "src".      */
+  variable var;
+  location_chain nextp;
+  int i;
+  bool found;
+
+  if (src && REG_P (src))
+    decl = var_debug_decl (REG_EXPR (src));
+  else if (src && MEM_P (src))
+    decl = var_debug_decl (MEM_EXPR (src));
+
+  if (src && decl)
+    {
+      decl_or_value dv = dv_from_decl (decl);
+
+      var = shared_hash_find (set->vars, dv);
+      if (var)
+	{
+	  found = false;
+	  for (i = 0; i < var->n_var_parts && !found; i++)
+	    for (nextp = var->var_part[i].loc_chain; nextp && !found;
+		 nextp = nextp->next)
+	      if (rtx_equal_p (nextp->loc, src))
+		{
+		  set_src = nextp->set_src;
+		  found = true;
+		}
+
+	}
+    }
+
+  return set_src;
+}
+
+/* Compute the changes of variable locations in the basic block BB.  */
+
+static bool
+compute_bb_dataflow (basic_block bb)
+{
+  unsigned int i;
+  micro_operation *mo;
+  bool changed;
+  dataflow_set old_out;
+  dataflow_set *in = &VTI (bb)->in;
+  dataflow_set *out = &VTI (bb)->out;
+
+  dataflow_set_init (&old_out);
+  dataflow_set_copy (&old_out, out);
+  dataflow_set_copy (out, in);
+
+  if (MAY_HAVE_DEBUG_INSNS)
+    local_get_addr_cache = pointer_map_create ();
+
+  FOR_EACH_VEC_ELT (VTI (bb)->mos, i, mo)
+    {
+      rtx insn = mo->insn;
+
+      switch (mo->type)
+	{
+	  case MO_CALL:
+	    dataflow_set_clear_at_call (out);
+	    break;
+
+	  case MO_USE:
+	    {
+	      rtx loc = mo->u.loc;
+
+	      if (REG_P (loc))
+		var_reg_set (out, loc, VAR_INIT_STATUS_UNINITIALIZED, NULL);
+	      else if (MEM_P (loc))
+		var_mem_set (out, loc, VAR_INIT_STATUS_UNINITIALIZED, NULL);
+	    }
+	    break;
+
+	  case MO_VAL_LOC:
+	    {
+	      rtx loc = mo->u.loc;
+	      rtx val, vloc;
+	      tree var;
+
+	      if (GET_CODE (loc) == CONCAT)
+		{
+		  val = XEXP (loc, 0);
+		  vloc = XEXP (loc, 1);
+		}
+	      else
+		{
+		  val = NULL_RTX;
+		  vloc = loc;
+		}
+
+	      var = PAT_VAR_LOCATION_DECL (vloc);
+
+	      clobber_variable_part (out, NULL_RTX,
+				     dv_from_decl (var), 0, NULL_RTX);
+	      if (val)
+		{
+		  if (VAL_NEEDS_RESOLUTION (loc))
+		    val_resolve (out, val, PAT_VAR_LOCATION_LOC (vloc), insn);
+		  set_variable_part (out, val, dv_from_decl (var), 0,
+				     VAR_INIT_STATUS_INITIALIZED, NULL_RTX,
+				     INSERT);
+		}
+	      else if (!VAR_LOC_UNKNOWN_P (PAT_VAR_LOCATION_LOC (vloc)))
+		set_variable_part (out, PAT_VAR_LOCATION_LOC (vloc),
+				   dv_from_decl (var), 0,
+				   VAR_INIT_STATUS_INITIALIZED, NULL_RTX,
+				   INSERT);
+	    }
+	    break;
+
+	  case MO_VAL_USE:
+	    {
+	      rtx loc = mo->u.loc;
+	      rtx val, vloc, uloc;
+
+	      vloc = uloc = XEXP (loc, 1);
+	      val = XEXP (loc, 0);
+
+	      if (GET_CODE (val) == CONCAT)
+		{
+		  uloc = XEXP (val, 1);
+		  val = XEXP (val, 0);
+		}
+
+	      if (VAL_NEEDS_RESOLUTION (loc))
+		val_resolve (out, val, vloc, insn);
+	      else
+		val_store (out, val, uloc, insn, false);
+
+	      if (VAL_HOLDS_TRACK_EXPR (loc))
+		{
+		  if (GET_CODE (uloc) == REG)
+		    var_reg_set (out, uloc, VAR_INIT_STATUS_UNINITIALIZED,
+				 NULL);
+		  else if (GET_CODE (uloc) == MEM)
+		    var_mem_set (out, uloc, VAR_INIT_STATUS_UNINITIALIZED,
+				 NULL);
+		}
+	    }
+	    break;
+
+	  case MO_VAL_SET:
+	    {
+	      rtx loc = mo->u.loc;
+	      rtx val, vloc, uloc;
+	      rtx dstv, srcv;
+
+	      vloc = loc;
+	      uloc = XEXP (vloc, 1);
+	      val = XEXP (vloc, 0);
+	      vloc = uloc;
+
+	      if (GET_CODE (uloc) == SET)
+		{
+		  dstv = SET_DEST (uloc);
+		  srcv = SET_SRC (uloc);
+		}
+	      else
+		{
+		  dstv = uloc;
+		  srcv = NULL;
+		}
+
+	      if (GET_CODE (val) == CONCAT)
+		{
+		  dstv = vloc = XEXP (val, 1);
+		  val = XEXP (val, 0);
+		}
+
+	      if (GET_CODE (vloc) == SET)
+		{
+		  srcv = SET_SRC (vloc);
+
+		  gcc_assert (val != srcv);
+		  gcc_assert (vloc == uloc || VAL_NEEDS_RESOLUTION (loc));
+
+		  dstv = vloc = SET_DEST (vloc);
+
+		  if (VAL_NEEDS_RESOLUTION (loc))
+		    val_resolve (out, val, srcv, insn);
+		}
+	      else if (VAL_NEEDS_RESOLUTION (loc))
+		{
+		  gcc_assert (GET_CODE (uloc) == SET
+			      && GET_CODE (SET_SRC (uloc)) == REG);
+		  val_resolve (out, val, SET_SRC (uloc), insn);
+		}
+
+	      if (VAL_HOLDS_TRACK_EXPR (loc))
+		{
+		  if (VAL_EXPR_IS_CLOBBERED (loc))
+		    {
+		      if (REG_P (uloc))
+			var_reg_delete (out, uloc, true);
+		      else if (MEM_P (uloc))
+			{
+			  gcc_assert (MEM_P (dstv));
+			  gcc_assert (MEM_ATTRS (dstv) == MEM_ATTRS (uloc));
+			  var_mem_delete (out, dstv, true);
+			}
+		    }
+		  else
+		    {
+		      bool copied_p = VAL_EXPR_IS_COPIED (loc);
+		      rtx src = NULL, dst = uloc;
+		      enum var_init_status status = VAR_INIT_STATUS_INITIALIZED;
+
+		      if (GET_CODE (uloc) == SET)
+			{
+			  src = SET_SRC (uloc);
+			  dst = SET_DEST (uloc);
+			}
+
+		      if (copied_p)
+			{
+			  if (flag_var_tracking_uninit)
+			    {
+			      status = find_src_status (in, src);
+
+			      if (status == VAR_INIT_STATUS_UNKNOWN)
+				status = find_src_status (out, src);
+			    }
+
+			  src = find_src_set_src (in, src);
+			}
+
+		      if (REG_P (dst))
+			var_reg_delete_and_set (out, dst, !copied_p,
+						status, srcv);
+		      else if (MEM_P (dst))
+			{
+			  gcc_assert (MEM_P (dstv));
+			  gcc_assert (MEM_ATTRS (dstv) == MEM_ATTRS (dst));
+			  var_mem_delete_and_set (out, dstv, !copied_p,
+						  status, srcv);
+			}
+		    }
+		}
+	      else if (REG_P (uloc))
+		var_regno_delete (out, REGNO (uloc));
+	      else if (MEM_P (uloc))
+		{
+		  gcc_checking_assert (GET_CODE (vloc) == MEM);
+		  gcc_checking_assert (dstv == vloc);
+		  if (dstv != vloc)
+		    clobber_overlapping_mems (out, vloc);
+		}
+
+	      val_store (out, val, dstv, insn, true);
+	    }
+	    break;
+
+	  case MO_SET:
+	    {
+	      rtx loc = mo->u.loc;
+	      rtx set_src = NULL;
+
+	      if (GET_CODE (loc) == SET)
+		{
+		  set_src = SET_SRC (loc);
+		  loc = SET_DEST (loc);
+		}
+
+	      if (REG_P (loc))
+		var_reg_delete_and_set (out, loc, true, VAR_INIT_STATUS_INITIALIZED,
+					set_src);
+	      else if (MEM_P (loc))
+		var_mem_delete_and_set (out, loc, true, VAR_INIT_STATUS_INITIALIZED,
+					set_src);
+	    }
+	    break;
+
+	  case MO_COPY:
+	    {
+	      rtx loc = mo->u.loc;
+	      enum var_init_status src_status;
+	      rtx set_src = NULL;
+
+	      if (GET_CODE (loc) == SET)
+		{
+		  set_src = SET_SRC (loc);
+		  loc = SET_DEST (loc);
+		}
+
+	      if (! flag_var_tracking_uninit)
+		src_status = VAR_INIT_STATUS_INITIALIZED;
+	      else
+		{
+		  src_status = find_src_status (in, set_src);
+
+		  if (src_status == VAR_INIT_STATUS_UNKNOWN)
+		    src_status = find_src_status (out, set_src);
+		}
+
+	      set_src = find_src_set_src (in, set_src);
+
+	      if (REG_P (loc))
+		var_reg_delete_and_set (out, loc, false, src_status, set_src);
+	      else if (MEM_P (loc))
+		var_mem_delete_and_set (out, loc, false, src_status, set_src);
+	    }
+	    break;
+
+	  case MO_USE_NO_VAR:
+	    {
+	      rtx loc = mo->u.loc;
+
+	      if (REG_P (loc))
+		var_reg_delete (out, loc, false);
+	      else if (MEM_P (loc))
+		var_mem_delete (out, loc, false);
+	    }
+	    break;
+
+	  case MO_CLOBBER:
+	    {
+	      rtx loc = mo->u.loc;
+
+	      if (REG_P (loc))
+		var_reg_delete (out, loc, true);
+	      else if (MEM_P (loc))
+		var_mem_delete (out, loc, true);
+	    }
+	    break;
+
+	  case MO_ADJUST:
+	    out->stack_adjust += mo->u.adjust;
+	    break;
+	}
+    }
+
+  if (MAY_HAVE_DEBUG_INSNS)
+    {
+      pointer_map_destroy (local_get_addr_cache);
+      local_get_addr_cache = NULL;
+
+      dataflow_set_equiv_regs (out);
+      shared_hash_htab (out->vars)
+	.traverse <dataflow_set *, canonicalize_values_mark> (out);
+      shared_hash_htab (out->vars)
+	.traverse <dataflow_set *, canonicalize_values_star> (out);
+#if ENABLE_CHECKING
+      shared_hash_htab (out->vars)
+	.traverse <dataflow_set *, canonicalize_loc_order_check> (out);
+#endif
+    }
+  changed = dataflow_set_different (&old_out, out);
+  dataflow_set_destroy (&old_out);
+  return changed;
+}
+
+/* Find the locations of variables in the whole function.  */
+
+static bool
+vt_find_locations (void)
+{
+  fibheap_t worklist, pending, fibheap_swap;
+  sbitmap visited, in_worklist, in_pending, sbitmap_swap;
+  basic_block bb;
+  edge e;
+  int *bb_order;
+  int *rc_order;
+  int i;
+  int htabsz = 0;
+  int htabmax = PARAM_VALUE (PARAM_MAX_VARTRACK_SIZE);
+  bool success = true;
+
+  timevar_push (TV_VAR_TRACKING_DATAFLOW);
+  /* Compute reverse completion order of depth first search of the CFG
+     so that the data-flow runs faster.  */
+  rc_order = XNEWVEC (int, n_basic_blocks_for_fn (cfun) - NUM_FIXED_BLOCKS);
+  bb_order = XNEWVEC (int, last_basic_block_for_fn (cfun));
+  pre_and_rev_post_order_compute (NULL, rc_order, false);
+  for (i = 0; i < n_basic_blocks_for_fn (cfun) - NUM_FIXED_BLOCKS; i++)
+    bb_order[rc_order[i]] = i;
+  free (rc_order);
+
+  worklist = fibheap_new ();
+  pending = fibheap_new ();
+  visited = sbitmap_alloc (last_basic_block_for_fn (cfun));
+  in_worklist = sbitmap_alloc (last_basic_block_for_fn (cfun));
+  in_pending = sbitmap_alloc (last_basic_block_for_fn (cfun));
+  bitmap_clear (in_worklist);
+
+  FOR_EACH_BB_FN (bb, cfun)
+    fibheap_insert (pending, bb_order[bb->index], bb);
+  bitmap_ones (in_pending);
+
+  while (success && !fibheap_empty (pending))
+    {
+      fibheap_swap = pending;
+      pending = worklist;
+      worklist = fibheap_swap;
+      sbitmap_swap = in_pending;
+      in_pending = in_worklist;
+      in_worklist = sbitmap_swap;
+
+      bitmap_clear (visited);
+
+      while (!fibheap_empty (worklist))
+	{
+	  bb = (basic_block) fibheap_extract_min (worklist);
+	  bitmap_clear_bit (in_worklist, bb->index);
+	  gcc_assert (!bitmap_bit_p (visited, bb->index));
+	  if (!bitmap_bit_p (visited, bb->index))
+	    {
+	      bool changed;
+	      edge_iterator ei;
+	      int oldinsz, oldoutsz;
+
+	      bitmap_set_bit (visited, bb->index);
+
+	      if (VTI (bb)->in.vars)
+		{
+		  htabsz
+		    -= shared_hash_htab (VTI (bb)->in.vars).size ()
+			+ shared_hash_htab (VTI (bb)->out.vars).size ();
+		  oldinsz = shared_hash_htab (VTI (bb)->in.vars).elements ();
+		  oldoutsz = shared_hash_htab (VTI (bb)->out.vars).elements ();
+		}
+	      else
+		oldinsz = oldoutsz = 0;
+
+	      if (MAY_HAVE_DEBUG_INSNS)
+		{
+		  dataflow_set *in = &VTI (bb)->in, *first_out = NULL;
+		  bool first = true, adjust = false;
+
+		  /* Calculate the IN set as the intersection of
+		     predecessor OUT sets.  */
+
+		  dataflow_set_clear (in);
+		  dst_can_be_shared = true;
+
+		  FOR_EACH_EDGE (e, ei, bb->preds)
+		    if (!VTI (e->src)->flooded)
+		      gcc_assert (bb_order[bb->index]
+				  <= bb_order[e->src->index]);
+		    else if (first)
+		      {
+			dataflow_set_copy (in, &VTI (e->src)->out);
+			first_out = &VTI (e->src)->out;
+			first = false;
+		      }
+		    else
+		      {
+			dataflow_set_merge (in, &VTI (e->src)->out);
+			adjust = true;
+		      }
+
+		  if (adjust)
+		    {
+		      dataflow_post_merge_adjust (in, &VTI (bb)->permp);
+#if ENABLE_CHECKING
+		      /* Merge and merge_adjust should keep entries in
+			 canonical order.  */
+		      shared_hash_htab (in->vars)
+			.traverse <dataflow_set *,
+				   canonicalize_loc_order_check> (in);
+#endif
+		      if (dst_can_be_shared)
+			{
+			  shared_hash_destroy (in->vars);
+			  in->vars = shared_hash_copy (first_out->vars);
+			}
+		    }
+
+		  VTI (bb)->flooded = true;
+		}
+	      else
+		{
+		  /* Calculate the IN set as union of predecessor OUT sets.  */
+		  dataflow_set_clear (&VTI (bb)->in);
+		  FOR_EACH_EDGE (e, ei, bb->preds)
+		    dataflow_set_union (&VTI (bb)->in, &VTI (e->src)->out);
+		}
+
+	      changed = compute_bb_dataflow (bb);
+	      htabsz += shared_hash_htab (VTI (bb)->in.vars).size ()
+			 + shared_hash_htab (VTI (bb)->out.vars).size ();
+
+	      if (htabmax && htabsz > htabmax)
+		{
+		  if (MAY_HAVE_DEBUG_INSNS)
+		    inform (DECL_SOURCE_LOCATION (cfun->decl),
+			    "variable tracking size limit exceeded with "
+			    "-fvar-tracking-assignments, retrying without");
+		  else
+		    inform (DECL_SOURCE_LOCATION (cfun->decl),
+			    "variable tracking size limit exceeded");
+		  success = false;
+		  break;
+		}
+
+	      if (changed)
+		{
+		  FOR_EACH_EDGE (e, ei, bb->succs)
+		    {
+		      if (e->dest == EXIT_BLOCK_PTR_FOR_FN (cfun))
+			continue;
+
+		      if (bitmap_bit_p (visited, e->dest->index))
+			{
+			  if (!bitmap_bit_p (in_pending, e->dest->index))
+			    {
+			      /* Send E->DEST to next round.  */
+			      bitmap_set_bit (in_pending, e->dest->index);
+			      fibheap_insert (pending,
+					      bb_order[e->dest->index],
+					      e->dest);
+			    }
+			}
+		      else if (!bitmap_bit_p (in_worklist, e->dest->index))
+			{
+			  /* Add E->DEST to current round.  */
+			  bitmap_set_bit (in_worklist, e->dest->index);
+			  fibheap_insert (worklist, bb_order[e->dest->index],
+					  e->dest);
+			}
+		    }
+		}
+
+	      if (dump_file)
+		fprintf (dump_file,
+			 "BB %i: in %i (was %i), out %i (was %i), rem %i + %i, tsz %i\n",
+			 bb->index,
+			 (int)shared_hash_htab (VTI (bb)->in.vars).size (),
+			 oldinsz,
+			 (int)shared_hash_htab (VTI (bb)->out.vars).size (),
+			 oldoutsz,
+			 (int)worklist->nodes, (int)pending->nodes, htabsz);
+
+	      if (dump_file && (dump_flags & TDF_DETAILS))
+		{
+		  fprintf (dump_file, "BB %i IN:\n", bb->index);
+		  dump_dataflow_set (&VTI (bb)->in);
+		  fprintf (dump_file, "BB %i OUT:\n", bb->index);
+		  dump_dataflow_set (&VTI (bb)->out);
+		}
+	    }
+	}
+    }
+
+  if (success && MAY_HAVE_DEBUG_INSNS)
+    FOR_EACH_BB_FN (bb, cfun)
+      gcc_assert (VTI (bb)->flooded);
+
+  free (bb_order);
+  fibheap_delete (worklist);
+  fibheap_delete (pending);
+  sbitmap_free (visited);
+  sbitmap_free (in_worklist);
+  sbitmap_free (in_pending);
+
+  timevar_pop (TV_VAR_TRACKING_DATAFLOW);
+  return success;
+}
+
+/* Print the content of the LIST to dump file.  */
+
+static void
+dump_attrs_list (attrs list)
+{
+  for (; list; list = list->next)
+    {
+      if (dv_is_decl_p (list->dv))
+	print_mem_expr (dump_file, dv_as_decl (list->dv));
+      else
+	print_rtl_single (dump_file, dv_as_value (list->dv));
+      fprintf (dump_file, "+" HOST_WIDE_INT_PRINT_DEC, list->offset);
+    }
+  fprintf (dump_file, "\n");
+}
+
+/* Print the information about variable *SLOT to dump file.  */
+
+int
+dump_var_tracking_slot (variable_def **slot, void *data ATTRIBUTE_UNUSED)
+{
+  variable var = *slot;
+
+  dump_var (var);
+
+  /* Continue traversing the hash table.  */
+  return 1;
+}
+
+/* Print the information about variable VAR to dump file.  */
+
+static void
+dump_var (variable var)
+{
+  int i;
+  location_chain node;
+
+  if (dv_is_decl_p (var->dv))
+    {
+      const_tree decl = dv_as_decl (var->dv);
+
+      if (DECL_NAME (decl))
+	{
+	  fprintf (dump_file, "  name: %s",
+		   IDENTIFIER_POINTER (DECL_NAME (decl)));
+	  if (dump_flags & TDF_UID)
+	    fprintf (dump_file, "D.%u", DECL_UID (decl));
+	}
+      else if (TREE_CODE (decl) == DEBUG_EXPR_DECL)
+	fprintf (dump_file, "  name: D#%u", DEBUG_TEMP_UID (decl));
+      else
+	fprintf (dump_file, "  name: D.%u", DECL_UID (decl));
+      fprintf (dump_file, "\n");
+    }
+  else
+    {
+      fputc (' ', dump_file);
+      print_rtl_single (dump_file, dv_as_value (var->dv));
+    }
+
+  for (i = 0; i < var->n_var_parts; i++)
+    {
+      fprintf (dump_file, "    offset %ld\n",
+	       (long)(var->onepart ? 0 : VAR_PART_OFFSET (var, i)));
+      for (node = var->var_part[i].loc_chain; node; node = node->next)
+	{
+	  fprintf (dump_file, "      ");
+	  if (node->init == VAR_INIT_STATUS_UNINITIALIZED)
+	    fprintf (dump_file, "[uninit]");
+	  print_rtl_single (dump_file, node->loc);
+	}
+    }
+}
+
+/* Print the information about variables from hash table VARS to dump file.  */
+
+static void
+dump_vars (variable_table_type vars)
+{
+  if (vars.elements () > 0)
+    {
+      fprintf (dump_file, "Variables:\n");
+      vars.traverse <void *, dump_var_tracking_slot> (NULL);
+    }
+}
+
+/* Print the dataflow set SET to dump file.  */
+
+static void
+dump_dataflow_set (dataflow_set *set)
+{
+  int i;
+
+  fprintf (dump_file, "Stack adjustment: " HOST_WIDE_INT_PRINT_DEC "\n",
+	   set->stack_adjust);
+  for (i = 0; i < FIRST_PSEUDO_REGISTER; i++)
+    {
+      if (set->regs[i])
+	{
+	  fprintf (dump_file, "Reg %d:", i);
+	  dump_attrs_list (set->regs[i]);
+	}
+    }
+  dump_vars (shared_hash_htab (set->vars));
+  fprintf (dump_file, "\n");
+}
+
+/* Print the IN and OUT sets for each basic block to dump file.  */
+
+static void
+dump_dataflow_sets (void)
+{
+  basic_block bb;
+
+  FOR_EACH_BB_FN (bb, cfun)
+    {
+      fprintf (dump_file, "\nBasic block %d:\n", bb->index);
+      fprintf (dump_file, "IN:\n");
+      dump_dataflow_set (&VTI (bb)->in);
+      fprintf (dump_file, "OUT:\n");
+      dump_dataflow_set (&VTI (bb)->out);
+    }
+}
+
+/* Return the variable for DV in dropped_values, inserting one if
+   requested with INSERT.  */
+
+static inline variable
+variable_from_dropped (decl_or_value dv, enum insert_option insert)
+{
+  variable_def **slot;
+  variable empty_var;
+  onepart_enum_t onepart;
+
+  slot = dropped_values.find_slot_with_hash (dv, dv_htab_hash (dv), insert);
+
+  if (!slot)
+    return NULL;
+
+  if (*slot)
+    return *slot;
+
+  gcc_checking_assert (insert == INSERT);
+
+  onepart = dv_onepart_p (dv);
+
+  gcc_checking_assert (onepart == ONEPART_VALUE || onepart == ONEPART_DEXPR);
+
+  empty_var = (variable) pool_alloc (onepart_pool (onepart));
+  empty_var->dv = dv;
+  empty_var->refcount = 1;
+  empty_var->n_var_parts = 0;
+  empty_var->onepart = onepart;
+  empty_var->in_changed_variables = false;
+  empty_var->var_part[0].loc_chain = NULL;
+  empty_var->var_part[0].cur_loc = NULL;
+  VAR_LOC_1PAUX (empty_var) = NULL;
+  set_dv_changed (dv, true);
+
+  *slot = empty_var;
+
+  return empty_var;
+}
+
+/* Recover the one-part aux from dropped_values.  */
+
+static struct onepart_aux *
+recover_dropped_1paux (variable var)
+{
+  variable dvar;
+
+  gcc_checking_assert (var->onepart);
+
+  if (VAR_LOC_1PAUX (var))
+    return VAR_LOC_1PAUX (var);
+
+  if (var->onepart == ONEPART_VDECL)
+    return NULL;
+
+  dvar = variable_from_dropped (var->dv, NO_INSERT);
+
+  if (!dvar)
+    return NULL;
+
+  VAR_LOC_1PAUX (var) = VAR_LOC_1PAUX (dvar);
+  VAR_LOC_1PAUX (dvar) = NULL;
+
+  return VAR_LOC_1PAUX (var);
+}
+
+/* Add variable VAR to the hash table of changed variables and
+   if it has no locations delete it from SET's hash table.  */
+
+static void
+variable_was_changed (variable var, dataflow_set *set)
+{
+  hashval_t hash = dv_htab_hash (var->dv);
+
+  if (emit_notes)
+    {
+      variable_def **slot;
+
+      /* Remember this decl or VALUE has been added to changed_variables.  */
+      set_dv_changed (var->dv, true);
+
+      slot = changed_variables.find_slot_with_hash (var->dv, hash, INSERT);
+
+      if (*slot)
+	{
+	  variable old_var = *slot;
+	  gcc_assert (old_var->in_changed_variables);
+	  old_var->in_changed_variables = false;
+	  if (var != old_var && var->onepart)
+	    {
+	      /* Restore the auxiliary info from an empty variable
+		 previously created for changed_variables, so it is
+		 not lost.  */
+	      gcc_checking_assert (!VAR_LOC_1PAUX (var));
+	      VAR_LOC_1PAUX (var) = VAR_LOC_1PAUX (old_var);
+	      VAR_LOC_1PAUX (old_var) = NULL;
+	    }
+	  variable_htab_free (*slot);
+	}
+
+      if (set && var->n_var_parts == 0)
+	{
+	  onepart_enum_t onepart = var->onepart;
+	  variable empty_var = NULL;
+	  variable_def **dslot = NULL;
+
+	  if (onepart == ONEPART_VALUE || onepart == ONEPART_DEXPR)
+	    {
+	      dslot = dropped_values.find_slot_with_hash (var->dv,
+						dv_htab_hash (var->dv),
+						INSERT);
+	      empty_var = *dslot;
+
+	      if (empty_var)
+		{
+		  gcc_checking_assert (!empty_var->in_changed_variables);
+		  if (!VAR_LOC_1PAUX (var))
+		    {
+		      VAR_LOC_1PAUX (var) = VAR_LOC_1PAUX (empty_var);
+		      VAR_LOC_1PAUX (empty_var) = NULL;
+		    }
+		  else
+		    gcc_checking_assert (!VAR_LOC_1PAUX (empty_var));
+		}
+	    }
+
+	  if (!empty_var)
+	    {
+	      empty_var = (variable) pool_alloc (onepart_pool (onepart));
+	      empty_var->dv = var->dv;
+	      empty_var->refcount = 1;
+	      empty_var->n_var_parts = 0;
+	      empty_var->onepart = onepart;
+	      if (dslot)
+		{
+		  empty_var->refcount++;
+		  *dslot = empty_var;
+		}
+	    }
+	  else
+	    empty_var->refcount++;
+	  empty_var->in_changed_variables = true;
+	  *slot = empty_var;
+	  if (onepart)
+	    {
+	      empty_var->var_part[0].loc_chain = NULL;
+	      empty_var->var_part[0].cur_loc = NULL;
+	      VAR_LOC_1PAUX (empty_var) = VAR_LOC_1PAUX (var);
+	      VAR_LOC_1PAUX (var) = NULL;
+	    }
+	  goto drop_var;
+	}
+      else
+	{
+	  if (var->onepart && !VAR_LOC_1PAUX (var))
+	    recover_dropped_1paux (var);
+	  var->refcount++;
+	  var->in_changed_variables = true;
+	  *slot = var;
+	}
+    }
+  else
+    {
+      gcc_assert (set);
+      if (var->n_var_parts == 0)
+	{
+	  variable_def **slot;
+
+	drop_var:
+	  slot = shared_hash_find_slot_noinsert (set->vars, var->dv);
+	  if (slot)
+	    {
+	      if (shared_hash_shared (set->vars))
+		slot = shared_hash_find_slot_unshare (&set->vars, var->dv,
+						      NO_INSERT);
+	      shared_hash_htab (set->vars).clear_slot (slot);
+	    }
+	}
+    }
+}
+
+/* Look for the index in VAR->var_part corresponding to OFFSET.
+   Return -1 if not found.  If INSERTION_POINT is non-NULL, the
+   referenced int will be set to the index that the part has or should
+   have, if it should be inserted.  */
+
+static inline int
+find_variable_location_part (variable var, HOST_WIDE_INT offset,
+			     int *insertion_point)
+{
+  int pos, low, high;
+
+  if (var->onepart)
+    {
+      if (offset != 0)
+	return -1;
+
+      if (insertion_point)
+	*insertion_point = 0;
+
+      return var->n_var_parts - 1;
+    }
+
+  /* Find the location part.  */
+  low = 0;
+  high = var->n_var_parts;
+  while (low != high)
+    {
+      pos = (low + high) / 2;
+      if (VAR_PART_OFFSET (var, pos) < offset)
+	low = pos + 1;
+      else
+	high = pos;
+    }
+  pos = low;
+
+  if (insertion_point)
+    *insertion_point = pos;
+
+  if (pos < var->n_var_parts && VAR_PART_OFFSET (var, pos) == offset)
+    return pos;
+
+  return -1;
+}
+
+static variable_def **
+set_slot_part (dataflow_set *set, rtx loc, variable_def **slot,
+	       decl_or_value dv, HOST_WIDE_INT offset,
+	       enum var_init_status initialized, rtx set_src)
+{
+  int pos;
+  location_chain node, next;
+  location_chain *nextp;
+  variable var;
+  onepart_enum_t onepart;
+
+  var = *slot;
+
+  if (var)
+    onepart = var->onepart;
+  else
+    onepart = dv_onepart_p (dv);
+
+  gcc_checking_assert (offset == 0 || !onepart);
+  gcc_checking_assert (loc != dv_as_opaque (dv));
+
+  if (! flag_var_tracking_uninit)
+    initialized = VAR_INIT_STATUS_INITIALIZED;
+
+  if (!var)
+    {
+      /* Create new variable information.  */
+      var = (variable) pool_alloc (onepart_pool (onepart));
+      var->dv = dv;
+      var->refcount = 1;
+      var->n_var_parts = 1;
+      var->onepart = onepart;
+      var->in_changed_variables = false;
+      if (var->onepart)
+	VAR_LOC_1PAUX (var) = NULL;
+      else
+	VAR_PART_OFFSET (var, 0) = offset;
+      var->var_part[0].loc_chain = NULL;
+      var->var_part[0].cur_loc = NULL;
+      *slot = var;
+      pos = 0;
+      nextp = &var->var_part[0].loc_chain;
+    }
+  else if (onepart)
+    {
+      int r = -1, c = 0;
+
+      gcc_assert (dv_as_opaque (var->dv) == dv_as_opaque (dv));
+
+      pos = 0;
+
+      if (GET_CODE (loc) == VALUE)
+	{
+	  for (nextp = &var->var_part[0].loc_chain; (node = *nextp);
+	       nextp = &node->next)
+	    if (GET_CODE (node->loc) == VALUE)
+	      {
+		if (node->loc == loc)
+		  {
+		    r = 0;
+		    break;
+		  }
+		if (canon_value_cmp (node->loc, loc))
+		  c++;
+		else
+		  {
+		    r = 1;
+		    break;
+		  }
+	      }
+	    else if (REG_P (node->loc) || MEM_P (node->loc))
+	      c++;
+	    else
+	      {
+		r = 1;
+		break;
+	      }
+	}
+      else if (REG_P (loc))
+	{
+	  for (nextp = &var->var_part[0].loc_chain; (node = *nextp);
+	       nextp = &node->next)
+	    if (REG_P (node->loc))
+	      {
+		if (REGNO (node->loc) < REGNO (loc))
+		  c++;
+		else
+		  {
+		    if (REGNO (node->loc) == REGNO (loc))
+		      r = 0;
+		    else
+		      r = 1;
+		    break;
+		  }
+	      }
+	    else
+	      {
+		r = 1;
+		break;
+	      }
+	}
+      else if (MEM_P (loc))
+	{
+	  for (nextp = &var->var_part[0].loc_chain; (node = *nextp);
+	       nextp = &node->next)
+	    if (REG_P (node->loc))
+	      c++;
+	    else if (MEM_P (node->loc))
+	      {
+		if ((r = loc_cmp (XEXP (node->loc, 0), XEXP (loc, 0))) >= 0)
+		  break;
+		else
+		  c++;
+	      }
+	    else
+	      {
+		r = 1;
+		break;
+	      }
+	}
+      else
+	for (nextp = &var->var_part[0].loc_chain; (node = *nextp);
+	     nextp = &node->next)
+	  if ((r = loc_cmp (node->loc, loc)) >= 0)
+	    break;
+	  else
+	    c++;
+
+      if (r == 0)
+	return slot;
+
+      if (shared_var_p (var, set->vars))
+	{
+	  slot = unshare_variable (set, slot, var, initialized);
+	  var = *slot;
+	  for (nextp = &var->var_part[0].loc_chain; c;
+	       nextp = &(*nextp)->next)
+	    c--;
+	  gcc_assert ((!node && !*nextp) || node->loc == (*nextp)->loc);
+	}
+    }
+  else
+    {
+      int inspos = 0;
+
+      gcc_assert (dv_as_decl (var->dv) == dv_as_decl (dv));
+
+      pos = find_variable_location_part (var, offset, &inspos);
+
+      if (pos >= 0)
+	{
+	  node = var->var_part[pos].loc_chain;
+
+	  if (node
+	      && ((REG_P (node->loc) && REG_P (loc)
+		   && REGNO (node->loc) == REGNO (loc))
+		  || rtx_equal_p (node->loc, loc)))
+	    {
+	      /* LOC is in the beginning of the chain so we have nothing
+		 to do.  */
+	      if (node->init < initialized)
+		node->init = initialized;
+	      if (set_src != NULL)
+		node->set_src = set_src;
+
+	      return slot;
+	    }
+	  else
+	    {
+	      /* We have to make a copy of a shared variable.  */
+	      if (shared_var_p (var, set->vars))
+		{
+		  slot = unshare_variable (set, slot, var, initialized);
+		  var = *slot;
+		}
+	    }
+	}
+      else
+	{
+	  /* We have not found the location part, new one will be created.  */
+
+	  /* We have to make a copy of the shared variable.  */
+	  if (shared_var_p (var, set->vars))
+	    {
+	      slot = unshare_variable (set, slot, var, initialized);
+	      var = *slot;
+	    }
+
+	  /* We track only variables whose size is <= MAX_VAR_PARTS bytes
+	     thus there are at most MAX_VAR_PARTS different offsets.  */
+	  gcc_assert (var->n_var_parts < MAX_VAR_PARTS
+		      && (!var->n_var_parts || !onepart));
+
+	  /* We have to move the elements of array starting at index
+	     inspos to the next position.  */
+	  for (pos = var->n_var_parts; pos > inspos; pos--)
+	    var->var_part[pos] = var->var_part[pos - 1];
+
+	  var->n_var_parts++;
+	  gcc_checking_assert (!onepart);
+	  VAR_PART_OFFSET (var, pos) = offset;
+	  var->var_part[pos].loc_chain = NULL;
+	  var->var_part[pos].cur_loc = NULL;
+	}
+
+      /* Delete the location from the list.  */
+      nextp = &var->var_part[pos].loc_chain;
+      for (node = var->var_part[pos].loc_chain; node; node = next)
+	{
+	  next = node->next;
+	  if ((REG_P (node->loc) && REG_P (loc)
+	       && REGNO (node->loc) == REGNO (loc))
+	      || rtx_equal_p (node->loc, loc))
+	    {
+	      /* Save these values, to assign to the new node, before
+		 deleting this one.  */
+	      if (node->init > initialized)
+		initialized = node->init;
+	      if (node->set_src != NULL && set_src == NULL)
+		set_src = node->set_src;
+	      if (var->var_part[pos].cur_loc == node->loc)
+		var->var_part[pos].cur_loc = NULL;
+	      pool_free (loc_chain_pool, node);
+	      *nextp = next;
+	      break;
+	    }
+	  else
+	    nextp = &node->next;
+	}
+
+      nextp = &var->var_part[pos].loc_chain;
+    }
+
+  /* Add the location to the beginning.  */
+  node = (location_chain) pool_alloc (loc_chain_pool);
+  node->loc = loc;
+  node->init = initialized;
+  node->set_src = set_src;
+  node->next = *nextp;
+  *nextp = node;
+
+  /* If no location was emitted do so.  */
+  if (var->var_part[pos].cur_loc == NULL)
+    variable_was_changed (var, set);
+
+  return slot;
+}
+
+/* Set the part of variable's location in the dataflow set SET.  The
+   variable part is specified by variable's declaration in DV and
+   offset OFFSET and the part's location by LOC.  IOPT should be
+   NO_INSERT if the variable is known to be in SET already and the
+   variable hash table must not be resized, and INSERT otherwise.  */
+
+static void
+set_variable_part (dataflow_set *set, rtx loc,
+		   decl_or_value dv, HOST_WIDE_INT offset,
+		   enum var_init_status initialized, rtx set_src,
+		   enum insert_option iopt)
+{
+  variable_def **slot;
+
+  if (iopt == NO_INSERT)
+    slot = shared_hash_find_slot_noinsert (set->vars, dv);
+  else
+    {
+      slot = shared_hash_find_slot (set->vars, dv);
+      if (!slot)
+	slot = shared_hash_find_slot_unshare (&set->vars, dv, iopt);
+    }
+  set_slot_part (set, loc, slot, dv, offset, initialized, set_src);
+}
+
+/* Remove all recorded register locations for the given variable part
+   from dataflow set SET, except for those that are identical to loc.
+   The variable part is specified by variable's declaration or value
+   DV and offset OFFSET.  */
+
+static variable_def **
+clobber_slot_part (dataflow_set *set, rtx loc, variable_def **slot,
+		   HOST_WIDE_INT offset, rtx set_src)
+{
+  variable var = *slot;
+  int pos = find_variable_location_part (var, offset, NULL);
+
+  if (pos >= 0)
+    {
+      location_chain node, next;
+
+      /* Remove the register locations from the dataflow set.  */
+      next = var->var_part[pos].loc_chain;
+      for (node = next; node; node = next)
+	{
+	  next = node->next;
+	  if (node->loc != loc
+	      && (!flag_var_tracking_uninit
+		  || !set_src
+		  || MEM_P (set_src)
+		  || !rtx_equal_p (set_src, node->set_src)))
+	    {
+	      if (REG_P (node->loc))
+		{
+		  attrs anode, anext;
+		  attrs *anextp;
+
+		  /* Remove the variable part from the register's
+		     list, but preserve any other variable parts
+		     that might be regarded as live in that same
+		     register.  */
+		  anextp = &set->regs[REGNO (node->loc)];
+		  for (anode = *anextp; anode; anode = anext)
+		    {
+		      anext = anode->next;
+		      if (dv_as_opaque (anode->dv) == dv_as_opaque (var->dv)
+			  && anode->offset == offset)
+			{
+			  pool_free (attrs_pool, anode);
+			  *anextp = anext;
+			}
+		      else
+			anextp = &anode->next;
+		    }
+		}
+
+	      slot = delete_slot_part (set, node->loc, slot, offset);
+	    }
+	}
+    }
+
+  return slot;
+}
+
+/* Remove all recorded register locations for the given variable part
+   from dataflow set SET, except for those that are identical to loc.
+   The variable part is specified by variable's declaration or value
+   DV and offset OFFSET.  */
+
+static void
+clobber_variable_part (dataflow_set *set, rtx loc, decl_or_value dv,
+		       HOST_WIDE_INT offset, rtx set_src)
+{
+  variable_def **slot;
+
+  if (!dv_as_opaque (dv)
+      || (!dv_is_value_p (dv) && ! DECL_P (dv_as_decl (dv))))
+    return;
+
+  slot = shared_hash_find_slot_noinsert (set->vars, dv);
+  if (!slot)
+    return;
+
+  clobber_slot_part (set, loc, slot, offset, set_src);
+}
+
+/* Delete the part of variable's location from dataflow set SET.  The
+   variable part is specified by its SET->vars slot SLOT and offset
+   OFFSET and the part's location by LOC.  */
+
+static variable_def **
+delete_slot_part (dataflow_set *set, rtx loc, variable_def **slot,
+		  HOST_WIDE_INT offset)
+{
+  variable var = *slot;
+  int pos = find_variable_location_part (var, offset, NULL);
+
+  if (pos >= 0)
+    {
+      location_chain node, next;
+      location_chain *nextp;
+      bool changed;
+      rtx cur_loc;
+
+      if (shared_var_p (var, set->vars))
+	{
+	  /* If the variable contains the location part we have to
+	     make a copy of the variable.  */
+	  for (node = var->var_part[pos].loc_chain; node;
+	       node = node->next)
+	    {
+	      if ((REG_P (node->loc) && REG_P (loc)
+		   && REGNO (node->loc) == REGNO (loc))
+		  || rtx_equal_p (node->loc, loc))
+		{
+		  slot = unshare_variable (set, slot, var,
+					   VAR_INIT_STATUS_UNKNOWN);
+		  var = *slot;
+		  break;
+		}
+	    }
+	}
+
+      if (pos == 0 && var->onepart && VAR_LOC_1PAUX (var))
+	cur_loc = VAR_LOC_FROM (var);
+      else
+	cur_loc = var->var_part[pos].cur_loc;
+
+      /* Delete the location part.  */
+      changed = false;
+      nextp = &var->var_part[pos].loc_chain;
+      for (node = *nextp; node; node = next)
+	{
+	  next = node->next;
+	  if ((REG_P (node->loc) && REG_P (loc)
+	       && REGNO (node->loc) == REGNO (loc))
+	      || rtx_equal_p (node->loc, loc))
+	    {
+	      /* If we have deleted the location which was last emitted
+		 we have to emit new location so add the variable to set
+		 of changed variables.  */
+	      if (cur_loc == node->loc)
+		{
+		  changed = true;
+		  var->var_part[pos].cur_loc = NULL;
+		  if (pos == 0 && var->onepart && VAR_LOC_1PAUX (var))
+		    VAR_LOC_FROM (var) = NULL;
+		}
+	      pool_free (loc_chain_pool, node);
+	      *nextp = next;
+	      break;
+	    }
+	  else
+	    nextp = &node->next;
+	}
+
+      if (var->var_part[pos].loc_chain == NULL)
+	{
+	  changed = true;
+	  var->n_var_parts--;
+	  while (pos < var->n_var_parts)
+	    {
+	      var->var_part[pos] = var->var_part[pos + 1];
+	      pos++;
+	    }
+	}
+      if (changed)
+	variable_was_changed (var, set);
+    }
+
+  return slot;
+}
+
+/* Delete the part of variable's location from dataflow set SET.  The
+   variable part is specified by variable's declaration or value DV
+   and offset OFFSET and the part's location by LOC.  */
+
+static void
+delete_variable_part (dataflow_set *set, rtx loc, decl_or_value dv,
+		      HOST_WIDE_INT offset)
+{
+  variable_def **slot = shared_hash_find_slot_noinsert (set->vars, dv);
+  if (!slot)
+    return;
+
+  delete_slot_part (set, loc, slot, offset);
+}
+
+
+/* Structure for passing some other parameters to function
+   vt_expand_loc_callback.  */
+struct expand_loc_callback_data
+{
+  /* The variables and values active at this point.  */
+  variable_table_type vars;
+
+  /* Stack of values and debug_exprs under expansion, and their
+     children.  */
+  auto_vec<rtx, 4> expanding;
+
+  /* Stack of values and debug_exprs whose expansion hit recursion
+     cycles.  They will have VALUE_RECURSED_INTO marked when added to
+     this list.  This flag will be cleared if any of its dependencies
+     resolves to a valid location.  So, if the flag remains set at the
+     end of the search, we know no valid location for this one can
+     possibly exist.  */
+  auto_vec<rtx, 4> pending;
+
+  /* The maximum depth among the sub-expressions under expansion.
+     Zero indicates no expansion so far.  */
+  expand_depth depth;
+};
+
+/* Allocate the one-part auxiliary data structure for VAR, with enough
+   room for COUNT dependencies.  */
+
+static void
+loc_exp_dep_alloc (variable var, int count)
+{
+  size_t allocsize;
+
+  gcc_checking_assert (var->onepart);
+
+  /* We can be called with COUNT == 0 to allocate the data structure
+     without any dependencies, e.g. for the backlinks only.  However,
+     if we are specifying a COUNT, then the dependency list must have
+     been emptied before.  It would be possible to adjust pointers or
+     force it empty here, but this is better done at an earlier point
+     in the algorithm, so we instead leave an assertion to catch
+     errors.  */
+  gcc_checking_assert (!count
+		       || VAR_LOC_DEP_VEC (var) == NULL
+		       || VAR_LOC_DEP_VEC (var)->is_empty ());
+
+  if (VAR_LOC_1PAUX (var) && VAR_LOC_DEP_VEC (var)->space (count))
+    return;
+
+  allocsize = offsetof (struct onepart_aux, deps)
+	      + vec<loc_exp_dep, va_heap, vl_embed>::embedded_size (count);
+
+  if (VAR_LOC_1PAUX (var))
+    {
+      VAR_LOC_1PAUX (var) = XRESIZEVAR (struct onepart_aux,
+					VAR_LOC_1PAUX (var), allocsize);
+      /* If the reallocation moves the onepaux structure, the
+	 back-pointer to BACKLINKS in the first list member will still
+	 point to its old location.  Adjust it.  */
+      if (VAR_LOC_DEP_LST (var))
+	VAR_LOC_DEP_LST (var)->pprev = VAR_LOC_DEP_LSTP (var);
+    }
+  else
+    {
+      VAR_LOC_1PAUX (var) = XNEWVAR (struct onepart_aux, allocsize);
+      *VAR_LOC_DEP_LSTP (var) = NULL;
+      VAR_LOC_FROM (var) = NULL;
+      VAR_LOC_DEPTH (var).complexity = 0;
+      VAR_LOC_DEPTH (var).entryvals = 0;
+    }
+  VAR_LOC_DEP_VEC (var)->embedded_init (count);
+}
+
+/* Remove all entries from the vector of active dependencies of VAR,
+   removing them from the back-links lists too.  */
+
+static void
+loc_exp_dep_clear (variable var)
+{
+  while (VAR_LOC_DEP_VEC (var) && !VAR_LOC_DEP_VEC (var)->is_empty ())
+    {
+      loc_exp_dep *led = &VAR_LOC_DEP_VEC (var)->last ();
+      if (led->next)
+	led->next->pprev = led->pprev;
+      if (led->pprev)
+	*led->pprev = led->next;
+      VAR_LOC_DEP_VEC (var)->pop ();
+    }
+}
+
+/* Insert an active dependency from VAR on X to the vector of
+   dependencies, and add the corresponding back-link to X's list of
+   back-links in VARS.  */
+
+static void
+loc_exp_insert_dep (variable var, rtx x, variable_table_type vars)
+{
+  decl_or_value dv;
+  variable xvar;
+  loc_exp_dep *led;
+
+  dv = dv_from_rtx (x);
+
+  /* ??? Build a vector of variables parallel to EXPANDING, to avoid
+     an additional look up?  */
+  xvar = vars.find_with_hash (dv, dv_htab_hash (dv));
+
+  if (!xvar)
+    {
+      xvar = variable_from_dropped (dv, NO_INSERT);
+      gcc_checking_assert (xvar);
+    }
+
+  /* No point in adding the same backlink more than once.  This may
+     arise if say the same value appears in two complex expressions in
+     the same loc_list, or even more than once in a single
+     expression.  */
+  if (VAR_LOC_DEP_LST (xvar) && VAR_LOC_DEP_LST (xvar)->dv == var->dv)
+    return;
+
+  if (var->onepart == NOT_ONEPART)
+    led = (loc_exp_dep *) pool_alloc (loc_exp_dep_pool);
+  else
+    {
+      loc_exp_dep empty;
+      memset (&empty, 0, sizeof (empty));
+      VAR_LOC_DEP_VEC (var)->quick_push (empty);
+      led = &VAR_LOC_DEP_VEC (var)->last ();
+    }
+  led->dv = var->dv;
+  led->value = x;
+
+  loc_exp_dep_alloc (xvar, 0);
+  led->pprev = VAR_LOC_DEP_LSTP (xvar);
+  led->next = *led->pprev;
+  if (led->next)
+    led->next->pprev = &led->next;
+  *led->pprev = led;
+}
+
+/* Create active dependencies of VAR on COUNT values starting at
+   VALUE, and corresponding back-links to the entries in VARS.  Return
+   true if we found any pending-recursion results.  */
+
+static bool
+loc_exp_dep_set (variable var, rtx result, rtx *value, int count,
+		 variable_table_type vars)
+{
+  bool pending_recursion = false;
+
+  gcc_checking_assert (VAR_LOC_DEP_VEC (var) == NULL
+		       || VAR_LOC_DEP_VEC (var)->is_empty ());
+
+  /* Set up all dependencies from last_child (as set up at the end of
+     the loop above) to the end.  */
+  loc_exp_dep_alloc (var, count);
+
+  while (count--)
+    {
+      rtx x = *value++;
+
+      if (!pending_recursion)
+	pending_recursion = !result && VALUE_RECURSED_INTO (x);
+
+      loc_exp_insert_dep (var, x, vars);
+    }
+
+  return pending_recursion;
+}
+
+/* Notify the back-links of IVAR that are pending recursion that we
+   have found a non-NIL value for it, so they are cleared for another
+   attempt to compute a current location.  */
+
+static void
+notify_dependents_of_resolved_value (variable ivar, variable_table_type vars)
+{
+  loc_exp_dep *led, *next;
+
+  for (led = VAR_LOC_DEP_LST (ivar); led; led = next)
+    {
+      decl_or_value dv = led->dv;
+      variable var;
+
+      next = led->next;
+
+      if (dv_is_value_p (dv))
+	{
+	  rtx value = dv_as_value (dv);
+
+	  /* If we have already resolved it, leave it alone.  */
+	  if (!VALUE_RECURSED_INTO (value))
+	    continue;
+
+	  /* Check that VALUE_RECURSED_INTO, true from the test above,
+	     implies NO_LOC_P.  */
+	  gcc_checking_assert (NO_LOC_P (value));
+
+	  /* We won't notify variables that are being expanded,
+	     because their dependency list is cleared before
+	     recursing.  */
+	  NO_LOC_P (value) = false;
+	  VALUE_RECURSED_INTO (value) = false;
+
+	  gcc_checking_assert (dv_changed_p (dv));
+	}
+      else
+	{
+	  gcc_checking_assert (dv_onepart_p (dv) != NOT_ONEPART);
+	  if (!dv_changed_p (dv))
+	    continue;
+      }
+
+      var = vars.find_with_hash (dv, dv_htab_hash (dv));
+
+      if (!var)
+	var = variable_from_dropped (dv, NO_INSERT);
+
+      if (var)
+	notify_dependents_of_resolved_value (var, vars);
+
+      if (next)
+	next->pprev = led->pprev;
+      if (led->pprev)
+	*led->pprev = next;
+      led->next = NULL;
+      led->pprev = NULL;
+    }
+}
+
+static rtx vt_expand_loc_callback (rtx x, bitmap regs,
+				   int max_depth, void *data);
+
+/* Return the combined depth, when one sub-expression evaluated to
+   BEST_DEPTH and the previous known depth was SAVED_DEPTH.  */
+
+static inline expand_depth
+update_depth (expand_depth saved_depth, expand_depth best_depth)
+{
+  /* If we didn't find anything, stick with what we had.  */
+  if (!best_depth.complexity)
+    return saved_depth;
+
+  /* If we found hadn't found anything, use the depth of the current
+     expression.  Do NOT add one extra level, we want to compute the
+     maximum depth among sub-expressions.  We'll increment it later,
+     if appropriate.  */
+  if (!saved_depth.complexity)
+    return best_depth;
+
+  /* Combine the entryval count so that regardless of which one we
+     return, the entryval count is accurate.  */
+  best_depth.entryvals = saved_depth.entryvals
+    = best_depth.entryvals + saved_depth.entryvals;
+
+  if (saved_depth.complexity < best_depth.complexity)
+    return best_depth;
+  else
+    return saved_depth;
+}
+
+/* Expand VAR to a location RTX, updating its cur_loc.  Use REGS and
+   DATA for cselib expand callback.  If PENDRECP is given, indicate in
+   it whether any sub-expression couldn't be fully evaluated because
+   it is pending recursion resolution.  */
+
+static inline rtx
+vt_expand_var_loc_chain (variable var, bitmap regs, void *data, bool *pendrecp)
+{
+  struct expand_loc_callback_data *elcd
+    = (struct expand_loc_callback_data *) data;
+  location_chain loc, next;
+  rtx result = NULL;
+  int first_child, result_first_child, last_child;
+  bool pending_recursion;
+  rtx loc_from = NULL;
+  struct elt_loc_list *cloc = NULL;
+  expand_depth depth = { 0, 0 }, saved_depth = elcd->depth;
+  int wanted_entryvals, found_entryvals = 0;
+
+  /* Clear all backlinks pointing at this, so that we're not notified
+     while we're active.  */
+  loc_exp_dep_clear (var);
+
+ retry:
+  if (var->onepart == ONEPART_VALUE)
+    {
+      cselib_val *val = CSELIB_VAL_PTR (dv_as_value (var->dv));
+
+      gcc_checking_assert (cselib_preserved_value_p (val));
+
+      cloc = val->locs;
+    }
+
+  first_child = result_first_child = last_child
+    = elcd->expanding.length ();
+
+  wanted_entryvals = found_entryvals;
+
+  /* Attempt to expand each available location in turn.  */
+  for (next = loc = var->n_var_parts ? var->var_part[0].loc_chain : NULL;
+       loc || cloc; loc = next)
+    {
+      result_first_child = last_child;
+
+      if (!loc)
+	{
+	  loc_from = cloc->loc;
+	  next = loc;
+	  cloc = cloc->next;
+	  if (unsuitable_loc (loc_from))
+	    continue;
+	}
+      else
+	{
+	  loc_from = loc->loc;
+	  next = loc->next;
+	}
+
+      gcc_checking_assert (!unsuitable_loc (loc_from));
+
+      elcd->depth.complexity = elcd->depth.entryvals = 0;
+      result = cselib_expand_value_rtx_cb (loc_from, regs, EXPR_DEPTH,
+					   vt_expand_loc_callback, data);
+      last_child = elcd->expanding.length ();
+
+      if (result)
+	{
+	  depth = elcd->depth;
+
+	  gcc_checking_assert (depth.complexity
+			       || result_first_child == last_child);
+
+	  if (last_child - result_first_child != 1)
+	    {
+	      if (!depth.complexity && GET_CODE (result) == ENTRY_VALUE)
+		depth.entryvals++;
+	      depth.complexity++;
+	    }
+
+	  if (depth.complexity <= EXPR_USE_DEPTH)
+	    {
+	      if (depth.entryvals <= wanted_entryvals)
+		break;
+	      else if (!found_entryvals || depth.entryvals < found_entryvals)
+		found_entryvals = depth.entryvals;
+	    }
+
+	  result = NULL;
+	}
+
+      /* Set it up in case we leave the loop.  */
+      depth.complexity = depth.entryvals = 0;
+      loc_from = NULL;
+      result_first_child = first_child;
+    }
+
+  if (!loc_from && wanted_entryvals < found_entryvals)
+    {
+      /* We found entries with ENTRY_VALUEs and skipped them.  Since
+	 we could not find any expansions without ENTRY_VALUEs, but we
+	 found at least one with them, go back and get an entry with
+	 the minimum number ENTRY_VALUE count that we found.  We could
+	 avoid looping, but since each sub-loc is already resolved,
+	 the re-expansion should be trivial.  ??? Should we record all
+	 attempted locs as dependencies, so that we retry the
+	 expansion should any of them change, in the hope it can give
+	 us a new entry without an ENTRY_VALUE?  */
+      elcd->expanding.truncate (first_child);
+      goto retry;
+    }
+
+  /* Register all encountered dependencies as active.  */
+  pending_recursion = loc_exp_dep_set
+    (var, result, elcd->expanding.address () + result_first_child,
+     last_child - result_first_child, elcd->vars);
+
+  elcd->expanding.truncate (first_child);
+
+  /* Record where the expansion came from.  */
+  gcc_checking_assert (!result || !pending_recursion);
+  VAR_LOC_FROM (var) = loc_from;
+  VAR_LOC_DEPTH (var) = depth;
+
+  gcc_checking_assert (!depth.complexity == !result);
+
+  elcd->depth = update_depth (saved_depth, depth);
+
+  /* Indicate whether any of the dependencies are pending recursion
+     resolution.  */
+  if (pendrecp)
+    *pendrecp = pending_recursion;
+
+  if (!pendrecp || !pending_recursion)
+    var->var_part[0].cur_loc = result;
+
+  return result;
+}
+
+/* Callback for cselib_expand_value, that looks for expressions
+   holding the value in the var-tracking hash tables.  Return X for
+   standard processing, anything else is to be used as-is.  */
+
+static rtx
+vt_expand_loc_callback (rtx x, bitmap regs,
+			int max_depth ATTRIBUTE_UNUSED,
+			void *data)
+{
+  struct expand_loc_callback_data *elcd
+    = (struct expand_loc_callback_data *) data;
+  decl_or_value dv;
+  variable var;
+  rtx result, subreg;
+  bool pending_recursion = false;
+  bool from_empty = false;
+
+  switch (GET_CODE (x))
+    {
+    case SUBREG:
+      subreg = cselib_expand_value_rtx_cb (SUBREG_REG (x), regs,
+					   EXPR_DEPTH,
+					   vt_expand_loc_callback, data);
+
+      if (!subreg)
+	return NULL;
+
+      result = simplify_gen_subreg (GET_MODE (x), subreg,
+				    GET_MODE (SUBREG_REG (x)),
+				    SUBREG_BYTE (x));
+
+      /* Invalid SUBREGs are ok in debug info.  ??? We could try
+	 alternate expansions for the VALUE as well.  */
+      if (!result)
+	result = gen_rtx_raw_SUBREG (GET_MODE (x), subreg, SUBREG_BYTE (x));
+
+      return result;
+
+    case DEBUG_EXPR:
+    case VALUE:
+      dv = dv_from_rtx (x);
+      break;
+
+    default:
+      return x;
+    }
+
+  elcd->expanding.safe_push (x);
+
+  /* Check that VALUE_RECURSED_INTO implies NO_LOC_P.  */
+  gcc_checking_assert (!VALUE_RECURSED_INTO (x) || NO_LOC_P (x));
+
+  if (NO_LOC_P (x))
+    {
+      gcc_checking_assert (VALUE_RECURSED_INTO (x) || !dv_changed_p (dv));
+      return NULL;
+    }
+
+  var = elcd->vars.find_with_hash (dv, dv_htab_hash (dv));
+
+  if (!var)
+    {
+      from_empty = true;
+      var = variable_from_dropped (dv, INSERT);
+    }
+
+  gcc_checking_assert (var);
+
+  if (!dv_changed_p (dv))
+    {
+      gcc_checking_assert (!NO_LOC_P (x));
+      gcc_checking_assert (var->var_part[0].cur_loc);
+      gcc_checking_assert (VAR_LOC_1PAUX (var));
+      gcc_checking_assert (VAR_LOC_1PAUX (var)->depth.complexity);
+
+      elcd->depth = update_depth (elcd->depth, VAR_LOC_1PAUX (var)->depth);
+
+      return var->var_part[0].cur_loc;
+    }
+
+  VALUE_RECURSED_INTO (x) = true;
+  /* This is tentative, but it makes some tests simpler.  */
+  NO_LOC_P (x) = true;
+
+  gcc_checking_assert (var->n_var_parts == 1 || from_empty);
+
+  result = vt_expand_var_loc_chain (var, regs, data, &pending_recursion);
+
+  if (pending_recursion)
+    {
+      gcc_checking_assert (!result);
+      elcd->pending.safe_push (x);
+    }
+  else
+    {
+      NO_LOC_P (x) = !result;
+      VALUE_RECURSED_INTO (x) = false;
+      set_dv_changed (dv, false);
+
+      if (result)
+	notify_dependents_of_resolved_value (var, elcd->vars);
+    }
+
+  return result;
+}
+
+/* While expanding variables, we may encounter recursion cycles
+   because of mutual (possibly indirect) dependencies between two
+   particular variables (or values), say A and B.  If we're trying to
+   expand A when we get to B, which in turn attempts to expand A, if
+   we can't find any other expansion for B, we'll add B to this
+   pending-recursion stack, and tentatively return NULL for its
+   location.  This tentative value will be used for any other
+   occurrences of B, unless A gets some other location, in which case
+   it will notify B that it is worth another try at computing a
+   location for it, and it will use the location computed for A then.
+   At the end of the expansion, the tentative NULL locations become
+   final for all members of PENDING that didn't get a notification.
+   This function performs this finalization of NULL locations.  */
+
+static void
+resolve_expansions_pending_recursion (vec<rtx, va_heap> *pending)
+{
+  while (!pending->is_empty ())
+    {
+      rtx x = pending->pop ();
+      decl_or_value dv;
+
+      if (!VALUE_RECURSED_INTO (x))
+	continue;
+
+      gcc_checking_assert (NO_LOC_P (x));
+      VALUE_RECURSED_INTO (x) = false;
+      dv = dv_from_rtx (x);
+      gcc_checking_assert (dv_changed_p (dv));
+      set_dv_changed (dv, false);
+    }
+}
+
+/* Initialize expand_loc_callback_data D with variable hash table V.
+   It must be a macro because of alloca (vec stack).  */
+#define INIT_ELCD(d, v)						\
+  do								\
+    {								\
+      (d).vars = (v);						\
+      (d).depth.complexity = (d).depth.entryvals = 0;		\
+    }								\
+  while (0)
+/* Finalize expand_loc_callback_data D, resolved to location L.  */
+#define FINI_ELCD(d, l)						\
+  do								\
+    {								\
+      resolve_expansions_pending_recursion (&(d).pending);	\
+      (d).pending.release ();					\
+      (d).expanding.release ();					\
+								\
+      if ((l) && MEM_P (l))					\
+	(l) = targetm.delegitimize_address (l);			\
+    }								\
+  while (0)
+
+/* Expand VALUEs and DEBUG_EXPRs in LOC to a location, using the
+   equivalences in VARS, updating their CUR_LOCs in the process.  */
+
+static rtx
+vt_expand_loc (rtx loc, variable_table_type vars)
+{
+  struct expand_loc_callback_data data;
+  rtx result;
+
+  if (!MAY_HAVE_DEBUG_INSNS)
+    return loc;
+
+  INIT_ELCD (data, vars);
+
+  result = cselib_expand_value_rtx_cb (loc, scratch_regs, EXPR_DEPTH,
+				       vt_expand_loc_callback, &data);
+
+  FINI_ELCD (data, result);
+
+  return result;
+}
+
+/* Expand the one-part VARiable to a location, using the equivalences
+   in VARS, updating their CUR_LOCs in the process.  */
+
+static rtx
+vt_expand_1pvar (variable var, variable_table_type vars)
+{
+  struct expand_loc_callback_data data;
+  rtx loc;
+
+  gcc_checking_assert (var->onepart && var->n_var_parts == 1);
+
+  if (!dv_changed_p (var->dv))
+    return var->var_part[0].cur_loc;
+
+  INIT_ELCD (data, vars);
+
+  loc = vt_expand_var_loc_chain (var, scratch_regs, &data, NULL);
+
+  gcc_checking_assert (data.expanding.is_empty ());
+
+  FINI_ELCD (data, loc);
+
+  return loc;
+}
+
+/* Emit the NOTE_INSN_VAR_LOCATION for variable *VARP.  DATA contains
+   additional parameters: WHERE specifies whether the note shall be emitted
+   before or after instruction INSN.  */
+
+int
+emit_note_insn_var_location (variable_def **varp, emit_note_data *data)
+{
+  variable var = *varp;
+  rtx insn = data->insn;
+  enum emit_note_where where = data->where;
+  variable_table_type vars = data->vars;
+  rtx note, note_vl;
+  int i, j, n_var_parts;
+  bool complete;
+  enum var_init_status initialized = VAR_INIT_STATUS_UNINITIALIZED;
+  HOST_WIDE_INT last_limit;
+  tree type_size_unit;
+  HOST_WIDE_INT offsets[MAX_VAR_PARTS];
+  rtx loc[MAX_VAR_PARTS];
+  tree decl;
+  location_chain lc;
+
+  gcc_checking_assert (var->onepart == NOT_ONEPART
+		       || var->onepart == ONEPART_VDECL);
+
+  decl = dv_as_decl (var->dv);
+
+  complete = true;
+  last_limit = 0;
+  n_var_parts = 0;
+  if (!var->onepart)
+    for (i = 0; i < var->n_var_parts; i++)
+      if (var->var_part[i].cur_loc == NULL && var->var_part[i].loc_chain)
+	var->var_part[i].cur_loc = var->var_part[i].loc_chain->loc;
+  for (i = 0; i < var->n_var_parts; i++)
+    {
+      enum machine_mode mode, wider_mode;
+      rtx loc2;
+      HOST_WIDE_INT offset;
+
+      if (i == 0 && var->onepart)
+	{
+	  gcc_checking_assert (var->n_var_parts == 1);
+	  offset = 0;
+	  initialized = VAR_INIT_STATUS_INITIALIZED;
+	  loc2 = vt_expand_1pvar (var, vars);
+	}
+      else
+	{
+	  if (last_limit < VAR_PART_OFFSET (var, i))
+	    {
+	      complete = false;
+	      break;
+	    }
+	  else if (last_limit > VAR_PART_OFFSET (var, i))
+	    continue;
+	  offset = VAR_PART_OFFSET (var, i);
+	  loc2 = var->var_part[i].cur_loc;
+	  if (loc2 && GET_CODE (loc2) == MEM
+	      && GET_CODE (XEXP (loc2, 0)) == VALUE)
+	    {
+	      rtx depval = XEXP (loc2, 0);
+
+	      loc2 = vt_expand_loc (loc2, vars);
+
+	      if (loc2)
+		loc_exp_insert_dep (var, depval, vars);
+	    }
+	  if (!loc2)
+	    {
+	      complete = false;
+	      continue;
+	    }
+	  gcc_checking_assert (GET_CODE (loc2) != VALUE);
+	  for (lc = var->var_part[i].loc_chain; lc; lc = lc->next)
+	    if (var->var_part[i].cur_loc == lc->loc)
+	      {
+		initialized = lc->init;
+		break;
+	      }
+	  gcc_assert (lc);
+	}
+
+      offsets[n_var_parts] = offset;
+      if (!loc2)
+	{
+	  complete = false;
+	  continue;
+	}
+      loc[n_var_parts] = loc2;
+      mode = GET_MODE (var->var_part[i].cur_loc);
+      if (mode == VOIDmode && var->onepart)
+	mode = DECL_MODE (decl);
+      last_limit = offsets[n_var_parts] + GET_MODE_SIZE (mode);
+
+      /* Attempt to merge adjacent registers or memory.  */
+      wider_mode = GET_MODE_WIDER_MODE (mode);
+      for (j = i + 1; j < var->n_var_parts; j++)
+	if (last_limit <= VAR_PART_OFFSET (var, j))
+	  break;
+      if (j < var->n_var_parts
+	  && wider_mode != VOIDmode
+	  && var->var_part[j].cur_loc
+	  && mode == GET_MODE (var->var_part[j].cur_loc)
+	  && (REG_P (loc[n_var_parts]) || MEM_P (loc[n_var_parts]))
+	  && last_limit == (var->onepart ? 0 : VAR_PART_OFFSET (var, j))
+	  && (loc2 = vt_expand_loc (var->var_part[j].cur_loc, vars))
+	  && GET_CODE (loc[n_var_parts]) == GET_CODE (loc2))
+	{
+	  rtx new_loc = NULL;
+
+	  if (REG_P (loc[n_var_parts])
+	      && hard_regno_nregs[REGNO (loc[n_var_parts])][mode] * 2
+		 == hard_regno_nregs[REGNO (loc[n_var_parts])][wider_mode]
+	      && end_hard_regno (mode, REGNO (loc[n_var_parts]))
+		 == REGNO (loc2))
+	    {
+	      if (! WORDS_BIG_ENDIAN && ! BYTES_BIG_ENDIAN)
+		new_loc = simplify_subreg (wider_mode, loc[n_var_parts],
+					   mode, 0);
+	      else if (WORDS_BIG_ENDIAN && BYTES_BIG_ENDIAN)
+		new_loc = simplify_subreg (wider_mode, loc2, mode, 0);
+	      if (new_loc)
+		{
+		  if (!REG_P (new_loc)
+		      || REGNO (new_loc) != REGNO (loc[n_var_parts]))
+		    new_loc = NULL;
+		  else
+		    REG_ATTRS (new_loc) = REG_ATTRS (loc[n_var_parts]);
+		}
+	    }
+	  else if (MEM_P (loc[n_var_parts])
+		   && GET_CODE (XEXP (loc2, 0)) == PLUS
+		   && REG_P (XEXP (XEXP (loc2, 0), 0))
+		   && CONST_INT_P (XEXP (XEXP (loc2, 0), 1)))
+	    {
+	      if ((REG_P (XEXP (loc[n_var_parts], 0))
+		   && rtx_equal_p (XEXP (loc[n_var_parts], 0),
+				   XEXP (XEXP (loc2, 0), 0))
+		   && INTVAL (XEXP (XEXP (loc2, 0), 1))
+		      == GET_MODE_SIZE (mode))
+		  || (GET_CODE (XEXP (loc[n_var_parts], 0)) == PLUS
+		      && CONST_INT_P (XEXP (XEXP (loc[n_var_parts], 0), 1))
+		      && rtx_equal_p (XEXP (XEXP (loc[n_var_parts], 0), 0),
+				      XEXP (XEXP (loc2, 0), 0))
+		      && INTVAL (XEXP (XEXP (loc[n_var_parts], 0), 1))
+			 + GET_MODE_SIZE (mode)
+			 == INTVAL (XEXP (XEXP (loc2, 0), 1))))
+		new_loc = adjust_address_nv (loc[n_var_parts],
+					     wider_mode, 0);
+	    }
+
+	  if (new_loc)
+	    {
+	      loc[n_var_parts] = new_loc;
+	      mode = wider_mode;
+	      last_limit = offsets[n_var_parts] + GET_MODE_SIZE (mode);
+	      i = j;
+	    }
+	}
+      ++n_var_parts;
+    }
+  type_size_unit = TYPE_SIZE_UNIT (TREE_TYPE (decl));
+  if ((unsigned HOST_WIDE_INT) last_limit < TREE_INT_CST_LOW (type_size_unit))
+    complete = false;
+
+  if (! flag_var_tracking_uninit)
+    initialized = VAR_INIT_STATUS_INITIALIZED;
+
+  note_vl = NULL_RTX;
+  if (!complete)
+    note_vl = gen_rtx_VAR_LOCATION (VOIDmode, decl, NULL_RTX,
+				    (int) initialized);
+  else if (n_var_parts == 1)
+    {
+      rtx expr_list;
+
+      if (offsets[0] || GET_CODE (loc[0]) == PARALLEL)
+	expr_list = gen_rtx_EXPR_LIST (VOIDmode, loc[0], GEN_INT (offsets[0]));
+      else
+	expr_list = loc[0];
+
+      note_vl = gen_rtx_VAR_LOCATION (VOIDmode, decl, expr_list,
+				      (int) initialized);
+    }
+  else if (n_var_parts)
+    {
+      rtx parallel;
+
+      for (i = 0; i < n_var_parts; i++)
+	loc[i]
+	  = gen_rtx_EXPR_LIST (VOIDmode, loc[i], GEN_INT (offsets[i]));
+
+      parallel = gen_rtx_PARALLEL (VOIDmode,
+				   gen_rtvec_v (n_var_parts, loc));
+      note_vl = gen_rtx_VAR_LOCATION (VOIDmode, decl,
+				      parallel, (int) initialized);
+    }
+
+  if (where != EMIT_NOTE_BEFORE_INSN)
+    {
+      note = emit_note_after (NOTE_INSN_VAR_LOCATION, insn);
+      if (where == EMIT_NOTE_AFTER_CALL_INSN)
+	NOTE_DURING_CALL_P (note) = true;
+    }
+  else
+    {
+      /* Make sure that the call related notes come first.  */
+      while (NEXT_INSN (insn)
+	     && NOTE_P (insn)
+	     && ((NOTE_KIND (insn) == NOTE_INSN_VAR_LOCATION
+		  && NOTE_DURING_CALL_P (insn))
+		 || NOTE_KIND (insn) == NOTE_INSN_CALL_ARG_LOCATION))
+	insn = NEXT_INSN (insn);
+      if (NOTE_P (insn)
+	  && ((NOTE_KIND (insn) == NOTE_INSN_VAR_LOCATION
+	       && NOTE_DURING_CALL_P (insn))
+	      || NOTE_KIND (insn) == NOTE_INSN_CALL_ARG_LOCATION))
+	note = emit_note_after (NOTE_INSN_VAR_LOCATION, insn);
+      else
+	note = emit_note_before (NOTE_INSN_VAR_LOCATION, insn);
+    }
+  NOTE_VAR_LOCATION (note) = note_vl;
+
+  set_dv_changed (var->dv, false);
+  gcc_assert (var->in_changed_variables);
+  var->in_changed_variables = false;
+  changed_variables.clear_slot (varp);
+
+  /* Continue traversing the hash table.  */
+  return 1;
+}
+
+/* While traversing changed_variables, push onto DATA (a stack of RTX
+   values) entries that aren't user variables.  */
+
+int
+var_track_values_to_stack (variable_def **slot,
+			   vec<rtx, va_heap> *changed_values_stack)
+{
+  variable var = *slot;
+
+  if (var->onepart == ONEPART_VALUE)
+    changed_values_stack->safe_push (dv_as_value (var->dv));
+  else if (var->onepart == ONEPART_DEXPR)
+    changed_values_stack->safe_push (DECL_RTL_KNOWN_SET (dv_as_decl (var->dv)));
+
+  return 1;
+}
+
+/* Remove from changed_variables the entry whose DV corresponds to
+   value or debug_expr VAL.  */
+static void
+remove_value_from_changed_variables (rtx val)
+{
+  decl_or_value dv = dv_from_rtx (val);
+  variable_def **slot;
+  variable var;
+
+  slot = changed_variables.find_slot_with_hash (dv, dv_htab_hash (dv),
+						NO_INSERT);
+  var = *slot;
+  var->in_changed_variables = false;
+  changed_variables.clear_slot (slot);
+}
+
+/* If VAL (a value or debug_expr) has backlinks to variables actively
+   dependent on it in HTAB or in CHANGED_VARIABLES, mark them as
+   changed, adding to CHANGED_VALUES_STACK any dependencies that may
+   have dependencies of their own to notify.  */
+
+static void
+notify_dependents_of_changed_value (rtx val, variable_table_type htab,
+				    vec<rtx, va_heap> *changed_values_stack)
+{
+  variable_def **slot;
+  variable var;
+  loc_exp_dep *led;
+  decl_or_value dv = dv_from_rtx (val);
+
+  slot = changed_variables.find_slot_with_hash (dv, dv_htab_hash (dv),
+						NO_INSERT);
+  if (!slot)
+    slot = htab.find_slot_with_hash (dv, dv_htab_hash (dv), NO_INSERT);
+  if (!slot)
+    slot = dropped_values.find_slot_with_hash (dv, dv_htab_hash (dv),
+					       NO_INSERT);
+  var = *slot;
+
+  while ((led = VAR_LOC_DEP_LST (var)))
+    {
+      decl_or_value ldv = led->dv;
+      variable ivar;
+
+      /* Deactivate and remove the backlink, as it was “used up”.  It
+	 makes no sense to attempt to notify the same entity again:
+	 either it will be recomputed and re-register an active
+	 dependency, or it will still have the changed mark.  */
+      if (led->next)
+	led->next->pprev = led->pprev;
+      if (led->pprev)
+	*led->pprev = led->next;
+      led->next = NULL;
+      led->pprev = NULL;
+
+      if (dv_changed_p (ldv))
+	continue;
+
+      switch (dv_onepart_p (ldv))
+	{
+	case ONEPART_VALUE:
+	case ONEPART_DEXPR:
+	  set_dv_changed (ldv, true);
+	  changed_values_stack->safe_push (dv_as_rtx (ldv));
+	  break;
+
+	case ONEPART_VDECL:
+	  ivar = htab.find_with_hash (ldv, dv_htab_hash (ldv));
+	  gcc_checking_assert (!VAR_LOC_DEP_LST (ivar));
+	  variable_was_changed (ivar, NULL);
+	  break;
+
+	case NOT_ONEPART:
+	  pool_free (loc_exp_dep_pool, led);
+	  ivar = htab.find_with_hash (ldv, dv_htab_hash (ldv));
+	  if (ivar)
+	    {
+	      int i = ivar->n_var_parts;
+	      while (i--)
+		{
+		  rtx loc = ivar->var_part[i].cur_loc;
+
+		  if (loc && GET_CODE (loc) == MEM
+		      && XEXP (loc, 0) == val)
+		    {
+		      variable_was_changed (ivar, NULL);
+		      break;
+		    }
+		}
+	    }
+	  break;
+
+	default:
+	  gcc_unreachable ();
+	}
+    }
+}
+
+/* Take out of changed_variables any entries that don't refer to use
+   variables.  Back-propagate change notifications from values and
+   debug_exprs to their active dependencies in HTAB or in
+   CHANGED_VARIABLES.  */
+
+static void
+process_changed_values (variable_table_type htab)
+{
+  int i, n;
+  rtx val;
+  auto_vec<rtx, 20> changed_values_stack;
+
+  /* Move values from changed_variables to changed_values_stack.  */
+  changed_variables
+    .traverse <vec<rtx, va_heap>*, var_track_values_to_stack>
+      (&changed_values_stack);
+
+  /* Back-propagate change notifications in values while popping
+     them from the stack.  */
+  for (n = i = changed_values_stack.length ();
+       i > 0; i = changed_values_stack.length ())
+    {
+      val = changed_values_stack.pop ();
+      notify_dependents_of_changed_value (val, htab, &changed_values_stack);
+
+      /* This condition will hold when visiting each of the entries
+	 originally in changed_variables.  We can't remove them
+	 earlier because this could drop the backlinks before we got a
+	 chance to use them.  */
+      if (i == n)
+	{
+	  remove_value_from_changed_variables (val);
+	  n--;
+	}
+    }
+}
+
+/* Emit NOTE_INSN_VAR_LOCATION note for each variable from a chain
+   CHANGED_VARIABLES and delete this chain.  WHERE specifies whether
+   the notes shall be emitted before of after instruction INSN.  */
+
+static void
+emit_notes_for_changes (rtx insn, enum emit_note_where where,
+			shared_hash vars)
+{
+  emit_note_data data;
+  variable_table_type htab = shared_hash_htab (vars);
+
+  if (!changed_variables.elements ())
+    return;
+
+  if (MAY_HAVE_DEBUG_INSNS)
+    process_changed_values (htab);
+
+  data.insn = insn;
+  data.where = where;
+  data.vars = htab;
+
+  changed_variables
+    .traverse <emit_note_data*, emit_note_insn_var_location> (&data);
+}
+
+/* Add variable *SLOT to the chain CHANGED_VARIABLES if it differs from the
+   same variable in hash table DATA or is not there at all.  */
+
+int
+emit_notes_for_differences_1 (variable_def **slot, variable_table_type new_vars)
+{
+  variable old_var, new_var;
+
+  old_var = *slot;
+  new_var = new_vars.find_with_hash (old_var->dv, dv_htab_hash (old_var->dv));
+
+  if (!new_var)
+    {
+      /* Variable has disappeared.  */
+      variable empty_var = NULL;
+
+      if (old_var->onepart == ONEPART_VALUE
+	  || old_var->onepart == ONEPART_DEXPR)
+	{
+	  empty_var = variable_from_dropped (old_var->dv, NO_INSERT);
+	  if (empty_var)
+	    {
+	      gcc_checking_assert (!empty_var->in_changed_variables);
+	      if (!VAR_LOC_1PAUX (old_var))
+		{
+		  VAR_LOC_1PAUX (old_var) = VAR_LOC_1PAUX (empty_var);
+		  VAR_LOC_1PAUX (empty_var) = NULL;
+		}
+	      else
+		gcc_checking_assert (!VAR_LOC_1PAUX (empty_var));
+	    }
+	}
+
+      if (!empty_var)
+	{
+	  empty_var = (variable) pool_alloc (onepart_pool (old_var->onepart));
+	  empty_var->dv = old_var->dv;
+	  empty_var->refcount = 0;
+	  empty_var->n_var_parts = 0;
+	  empty_var->onepart = old_var->onepart;
+	  empty_var->in_changed_variables = false;
+	}
+
+      if (empty_var->onepart)
+	{
+	  /* Propagate the auxiliary data to (ultimately)
+	     changed_variables.  */
+	  empty_var->var_part[0].loc_chain = NULL;
+	  empty_var->var_part[0].cur_loc = NULL;
+	  VAR_LOC_1PAUX (empty_var) = VAR_LOC_1PAUX (old_var);
+	  VAR_LOC_1PAUX (old_var) = NULL;
+	}
+      variable_was_changed (empty_var, NULL);
+      /* Continue traversing the hash table.  */
+      return 1;
+    }
+  /* Update cur_loc and one-part auxiliary data, before new_var goes
+     through variable_was_changed.  */
+  if (old_var != new_var && new_var->onepart)
+    {
+      gcc_checking_assert (VAR_LOC_1PAUX (new_var) == NULL);
+      VAR_LOC_1PAUX (new_var) = VAR_LOC_1PAUX (old_var);
+      VAR_LOC_1PAUX (old_var) = NULL;
+      new_var->var_part[0].cur_loc = old_var->var_part[0].cur_loc;
+    }
+  if (variable_different_p (old_var, new_var))
+    variable_was_changed (new_var, NULL);
+
+  /* Continue traversing the hash table.  */
+  return 1;
+}
+
+/* Add variable *SLOT to the chain CHANGED_VARIABLES if it is not in hash
+   table DATA.  */
+
+int
+emit_notes_for_differences_2 (variable_def **slot, variable_table_type old_vars)
+{
+  variable old_var, new_var;
+
+  new_var = *slot;
+  old_var = old_vars.find_with_hash (new_var->dv, dv_htab_hash (new_var->dv));
+  if (!old_var)
+    {
+      int i;
+      for (i = 0; i < new_var->n_var_parts; i++)
+	new_var->var_part[i].cur_loc = NULL;
+      variable_was_changed (new_var, NULL);
+    }
+
+  /* Continue traversing the hash table.  */
+  return 1;
+}
+
+/* Emit notes before INSN for differences between dataflow sets OLD_SET and
+   NEW_SET.  */
+
+static void
+emit_notes_for_differences (rtx insn, dataflow_set *old_set,
+			    dataflow_set *new_set)
+{
+  shared_hash_htab (old_set->vars)
+    .traverse <variable_table_type, emit_notes_for_differences_1>
+      (shared_hash_htab (new_set->vars));
+  shared_hash_htab (new_set->vars)
+    .traverse <variable_table_type, emit_notes_for_differences_2>
+      (shared_hash_htab (old_set->vars));
+  emit_notes_for_changes (insn, EMIT_NOTE_BEFORE_INSN, new_set->vars);
+}
+
+/* Return the next insn after INSN that is not a NOTE_INSN_VAR_LOCATION.  */
+
+static rtx
+next_non_note_insn_var_location (rtx insn)
+{
+  while (insn)
+    {
+      insn = NEXT_INSN (insn);
+      if (insn == 0
+	  || !NOTE_P (insn)
+	  || NOTE_KIND (insn) != NOTE_INSN_VAR_LOCATION)
+	break;
+    }
+
+  return insn;
+}
+
+/* Emit the notes for changes of location parts in the basic block BB.  */
+
+static void
+emit_notes_in_bb (basic_block bb, dataflow_set *set)
+{
+  unsigned int i;
+  micro_operation *mo;
+
+  dataflow_set_clear (set);
+  dataflow_set_copy (set, &VTI (bb)->in);
+
+  FOR_EACH_VEC_ELT (VTI (bb)->mos, i, mo)
+    {
+      rtx insn = mo->insn;
+      rtx next_insn = next_non_note_insn_var_location (insn);
+
+      switch (mo->type)
+	{
+	  case MO_CALL:
+	    dataflow_set_clear_at_call (set);
+	    emit_notes_for_changes (insn, EMIT_NOTE_AFTER_CALL_INSN, set->vars);
+	    {
+	      rtx arguments = mo->u.loc, *p = &arguments, note;
+	      while (*p)
+		{
+		  XEXP (XEXP (*p, 0), 1)
+		    = vt_expand_loc (XEXP (XEXP (*p, 0), 1),
+				     shared_hash_htab (set->vars));
+		  /* If expansion is successful, keep it in the list.  */
+		  if (XEXP (XEXP (*p, 0), 1))
+		    p = &XEXP (*p, 1);
+		  /* Otherwise, if the following item is data_value for it,
+		     drop it too too.  */
+		  else if (XEXP (*p, 1)
+			   && REG_P (XEXP (XEXP (*p, 0), 0))
+			   && MEM_P (XEXP (XEXP (XEXP (*p, 1), 0), 0))
+			   && REG_P (XEXP (XEXP (XEXP (XEXP (*p, 1), 0), 0),
+					   0))
+			   && REGNO (XEXP (XEXP (*p, 0), 0))
+			      == REGNO (XEXP (XEXP (XEXP (XEXP (*p, 1), 0),
+						    0), 0)))
+		    *p = XEXP (XEXP (*p, 1), 1);
+		  /* Just drop this item.  */
+		  else
+		    *p = XEXP (*p, 1);
+		}
+	      note = emit_note_after (NOTE_INSN_CALL_ARG_LOCATION, insn);
+	      NOTE_VAR_LOCATION (note) = arguments;
+	    }
+	    break;
+
+	  case MO_USE:
+	    {
+	      rtx loc = mo->u.loc;
+
+	      if (REG_P (loc))
+		var_reg_set (set, loc, VAR_INIT_STATUS_UNINITIALIZED, NULL);
+	      else
+		var_mem_set (set, loc, VAR_INIT_STATUS_UNINITIALIZED, NULL);
+
+	      emit_notes_for_changes (insn, EMIT_NOTE_BEFORE_INSN, set->vars);
+	    }
+	    break;
+
+	  case MO_VAL_LOC:
+	    {
+	      rtx loc = mo->u.loc;
+	      rtx val, vloc;
+	      tree var;
+
+	      if (GET_CODE (loc) == CONCAT)
+		{
+		  val = XEXP (loc, 0);
+		  vloc = XEXP (loc, 1);
+		}
+	      else
+		{
+		  val = NULL_RTX;
+		  vloc = loc;
+		}
+
+	      var = PAT_VAR_LOCATION_DECL (vloc);
+
+	      clobber_variable_part (set, NULL_RTX,
+				     dv_from_decl (var), 0, NULL_RTX);
+	      if (val)
+		{
+		  if (VAL_NEEDS_RESOLUTION (loc))
+		    val_resolve (set, val, PAT_VAR_LOCATION_LOC (vloc), insn);
+		  set_variable_part (set, val, dv_from_decl (var), 0,
+				     VAR_INIT_STATUS_INITIALIZED, NULL_RTX,
+				     INSERT);
+		}
+	      else if (!VAR_LOC_UNKNOWN_P (PAT_VAR_LOCATION_LOC (vloc)))
+		set_variable_part (set, PAT_VAR_LOCATION_LOC (vloc),
+				   dv_from_decl (var), 0,
+				   VAR_INIT_STATUS_INITIALIZED, NULL_RTX,
+				   INSERT);
+
+	      emit_notes_for_changes (insn, EMIT_NOTE_AFTER_INSN, set->vars);
+	    }
+	    break;
+
+	  case MO_VAL_USE:
+	    {
+	      rtx loc = mo->u.loc;
+	      rtx val, vloc, uloc;
+
+	      vloc = uloc = XEXP (loc, 1);
+	      val = XEXP (loc, 0);
+
+	      if (GET_CODE (val) == CONCAT)
+		{
+		  uloc = XEXP (val, 1);
+		  val = XEXP (val, 0);
+		}
+
+	      if (VAL_NEEDS_RESOLUTION (loc))
+		val_resolve (set, val, vloc, insn);
+	      else
+		val_store (set, val, uloc, insn, false);
+
+	      if (VAL_HOLDS_TRACK_EXPR (loc))
+		{
+		  if (GET_CODE (uloc) == REG)
+		    var_reg_set (set, uloc, VAR_INIT_STATUS_UNINITIALIZED,
+				 NULL);
+		  else if (GET_CODE (uloc) == MEM)
+		    var_mem_set (set, uloc, VAR_INIT_STATUS_UNINITIALIZED,
+				 NULL);
+		}
+
+	      emit_notes_for_changes (insn, EMIT_NOTE_BEFORE_INSN, set->vars);
+	    }
+	    break;
+
+	  case MO_VAL_SET:
+	    {
+	      rtx loc = mo->u.loc;
+	      rtx val, vloc, uloc;
+	      rtx dstv, srcv;
+
+	      vloc = loc;
+	      uloc = XEXP (vloc, 1);
+	      val = XEXP (vloc, 0);
+	      vloc = uloc;
+
+	      if (GET_CODE (uloc) == SET)
+		{
+		  dstv = SET_DEST (uloc);
+		  srcv = SET_SRC (uloc);
+		}
+	      else
+		{
+		  dstv = uloc;
+		  srcv = NULL;
+		}
+
+	      if (GET_CODE (val) == CONCAT)
+		{
+		  dstv = vloc = XEXP (val, 1);
+		  val = XEXP (val, 0);
+		}
+
+	      if (GET_CODE (vloc) == SET)
+		{
+		  srcv = SET_SRC (vloc);
+
+		  gcc_assert (val != srcv);
+		  gcc_assert (vloc == uloc || VAL_NEEDS_RESOLUTION (loc));
+
+		  dstv = vloc = SET_DEST (vloc);
+
+		  if (VAL_NEEDS_RESOLUTION (loc))
+		    val_resolve (set, val, srcv, insn);
+		}
+	      else if (VAL_NEEDS_RESOLUTION (loc))
+		{
+		  gcc_assert (GET_CODE (uloc) == SET
+			      && GET_CODE (SET_SRC (uloc)) == REG);
+		  val_resolve (set, val, SET_SRC (uloc), insn);
+		}
+
+	      if (VAL_HOLDS_TRACK_EXPR (loc))
+		{
+		  if (VAL_EXPR_IS_CLOBBERED (loc))
+		    {
+		      if (REG_P (uloc))
+			var_reg_delete (set, uloc, true);
+		      else if (MEM_P (uloc))
+			{
+			  gcc_assert (MEM_P (dstv));
+			  gcc_assert (MEM_ATTRS (dstv) == MEM_ATTRS (uloc));
+			  var_mem_delete (set, dstv, true);
+			}
+		    }
+		  else
+		    {
+		      bool copied_p = VAL_EXPR_IS_COPIED (loc);
+		      rtx src = NULL, dst = uloc;
+		      enum var_init_status status = VAR_INIT_STATUS_INITIALIZED;
+
+		      if (GET_CODE (uloc) == SET)
+			{
+			  src = SET_SRC (uloc);
+			  dst = SET_DEST (uloc);
+			}
+
+		      if (copied_p)
+			{
+			  status = find_src_status (set, src);
+
+			  src = find_src_set_src (set, src);
+			}
+
+		      if (REG_P (dst))
+			var_reg_delete_and_set (set, dst, !copied_p,
+						status, srcv);
+		      else if (MEM_P (dst))
+			{
+			  gcc_assert (MEM_P (dstv));
+			  gcc_assert (MEM_ATTRS (dstv) == MEM_ATTRS (dst));
+			  var_mem_delete_and_set (set, dstv, !copied_p,
+						  status, srcv);
+			}
+		    }
+		}
+	      else if (REG_P (uloc))
+		var_regno_delete (set, REGNO (uloc));
+	      else if (MEM_P (uloc))
+		{
+		  gcc_checking_assert (GET_CODE (vloc) == MEM);
+		  gcc_checking_assert (vloc == dstv);
+		  if (vloc != dstv)
+		    clobber_overlapping_mems (set, vloc);
+		}
+
+	      val_store (set, val, dstv, insn, true);
+
+	      emit_notes_for_changes (next_insn, EMIT_NOTE_BEFORE_INSN,
+				      set->vars);
+	    }
+	    break;
+
+	  case MO_SET:
+	    {
+	      rtx loc = mo->u.loc;
+	      rtx set_src = NULL;
+
+	      if (GET_CODE (loc) == SET)
+		{
+		  set_src = SET_SRC (loc);
+		  loc = SET_DEST (loc);
+		}
+
+	      if (REG_P (loc))
+		var_reg_delete_and_set (set, loc, true, VAR_INIT_STATUS_INITIALIZED,
+					set_src);
+	      else
+		var_mem_delete_and_set (set, loc, true, VAR_INIT_STATUS_INITIALIZED,
+					set_src);
+
+	      emit_notes_for_changes (next_insn, EMIT_NOTE_BEFORE_INSN,
+				      set->vars);
+	    }
+	    break;
+
+	  case MO_COPY:
+	    {
+	      rtx loc = mo->u.loc;
+	      enum var_init_status src_status;
+	      rtx set_src = NULL;
+
+	      if (GET_CODE (loc) == SET)
+		{
+		  set_src = SET_SRC (loc);
+		  loc = SET_DEST (loc);
+		}
+
+	      src_status = find_src_status (set, set_src);
+	      set_src = find_src_set_src (set, set_src);
+
+	      if (REG_P (loc))
+		var_reg_delete_and_set (set, loc, false, src_status, set_src);
+	      else
+		var_mem_delete_and_set (set, loc, false, src_status, set_src);
+
+	      emit_notes_for_changes (next_insn, EMIT_NOTE_BEFORE_INSN,
+				      set->vars);
+	    }
+	    break;
+
+	  case MO_USE_NO_VAR:
+	    {
+	      rtx loc = mo->u.loc;
+
+	      if (REG_P (loc))
+		var_reg_delete (set, loc, false);
+	      else
+		var_mem_delete (set, loc, false);
+
+	      emit_notes_for_changes (insn, EMIT_NOTE_AFTER_INSN, set->vars);
+	    }
+	    break;
+
+	  case MO_CLOBBER:
+	    {
+	      rtx loc = mo->u.loc;
+
+	      if (REG_P (loc))
+		var_reg_delete (set, loc, true);
+	      else
+		var_mem_delete (set, loc, true);
+
+	      emit_notes_for_changes (next_insn, EMIT_NOTE_BEFORE_INSN,
+				      set->vars);
+	    }
+	    break;
+
+	  case MO_ADJUST:
+	    set->stack_adjust += mo->u.adjust;
+	    break;
+	}
+    }
+}
+
+/* Emit notes for the whole function.  */
+
+static void
+vt_emit_notes (void)
+{
+  basic_block bb;
+  dataflow_set cur;
+
+  gcc_assert (!changed_variables.elements ());
+
+  /* Free memory occupied by the out hash tables, as they aren't used
+     anymore.  */
+  FOR_EACH_BB_FN (bb, cfun)
+    dataflow_set_clear (&VTI (bb)->out);
+
+  /* Enable emitting notes by functions (mainly by set_variable_part and
+     delete_variable_part).  */
+  emit_notes = true;
+
+  if (MAY_HAVE_DEBUG_INSNS)
+    {
+      dropped_values.create (cselib_get_next_uid () * 2);
+      loc_exp_dep_pool = create_alloc_pool ("loc_exp_dep pool",
+					    sizeof (loc_exp_dep), 64);
+    }
+
+  dataflow_set_init (&cur);
+
+  FOR_EACH_BB_FN (bb, cfun)
+    {
+      /* Emit the notes for changes of variable locations between two
+	 subsequent basic blocks.  */
+      emit_notes_for_differences (BB_HEAD (bb), &cur, &VTI (bb)->in);
+
+      if (MAY_HAVE_DEBUG_INSNS)
+	local_get_addr_cache = pointer_map_create ();
+
+      /* Emit the notes for the changes in the basic block itself.  */
+      emit_notes_in_bb (bb, &cur);
+
+      if (MAY_HAVE_DEBUG_INSNS)
+	pointer_map_destroy (local_get_addr_cache);
+      local_get_addr_cache = NULL;
+
+      /* Free memory occupied by the in hash table, we won't need it
+	 again.  */
+      dataflow_set_clear (&VTI (bb)->in);
+    }
+#ifdef ENABLE_CHECKING
+  shared_hash_htab (cur.vars)
+    .traverse <variable_table_type, emit_notes_for_differences_1>
+      (shared_hash_htab (empty_shared_hash));
+#endif
+  dataflow_set_destroy (&cur);
+
+  if (MAY_HAVE_DEBUG_INSNS)
+    dropped_values.dispose ();
+
+  emit_notes = false;
+}
+
+/* If there is a declaration and offset associated with register/memory RTL
+   assign declaration to *DECLP and offset to *OFFSETP, and return true.  */
+
+static bool
+vt_get_decl_and_offset (rtx rtl, tree *declp, HOST_WIDE_INT *offsetp)
+{
+  if (REG_P (rtl))
+    {
+      if (REG_ATTRS (rtl))
+	{
+	  *declp = REG_EXPR (rtl);
+	  *offsetp = REG_OFFSET (rtl);
+	  return true;
+	}
+    }
+  else if (GET_CODE (rtl) == PARALLEL)
+    {
+      tree decl = NULL_TREE;
+      HOST_WIDE_INT offset = MAX_VAR_PARTS;
+      int len = XVECLEN (rtl, 0), i;
+
+      for (i = 0; i < len; i++)
+	{
+	  rtx reg = XEXP (XVECEXP (rtl, 0, i), 0);
+	  if (!REG_P (reg) || !REG_ATTRS (reg))
+	    break;
+	  if (!decl)
+	    decl = REG_EXPR (reg);
+	  if (REG_EXPR (reg) != decl)
+	    break;
+	  if (REG_OFFSET (reg) < offset)
+	    offset = REG_OFFSET (reg);
+	}
+
+      if (i == len)
+	{
+	  *declp = decl;
+	  *offsetp = offset;
+	  return true;
+	}
+    }
+  else if (MEM_P (rtl))
+    {
+      if (MEM_ATTRS (rtl))
+	{
+	  *declp = MEM_EXPR (rtl);
+	  *offsetp = INT_MEM_OFFSET (rtl);
+	  return true;
+	}
+    }
+  return false;
+}
+
+/* Record the value for the ENTRY_VALUE of RTL as a global equivalence
+   of VAL.  */
+
+static void
+record_entry_value (cselib_val *val, rtx rtl)
+{
+  rtx ev = gen_rtx_ENTRY_VALUE (GET_MODE (rtl));
+
+  ENTRY_VALUE_EXP (ev) = rtl;
+
+  cselib_add_permanent_equiv (val, ev, get_insns ());
+}
+
+/* Insert function parameter PARM in IN and OUT sets of ENTRY_BLOCK.  */
+
+static void
+vt_add_function_parameter (tree parm)
+{
+  rtx decl_rtl = DECL_RTL_IF_SET (parm);
+  rtx incoming = DECL_INCOMING_RTL (parm);
+  tree decl;
+  enum machine_mode mode;
+  HOST_WIDE_INT offset;
+  dataflow_set *out;
+  decl_or_value dv;
+
+  if (TREE_CODE (parm) != PARM_DECL)
+    return;
+
+  if (!decl_rtl || !incoming)
+    return;
+
+  if (GET_MODE (decl_rtl) == BLKmode || GET_MODE (incoming) == BLKmode)
+    return;
+
+  /* If there is a DRAP register or a pseudo in internal_arg_pointer,
+     rewrite the incoming location of parameters passed on the stack
+     into MEMs based on the argument pointer, so that incoming doesn't
+     depend on a pseudo.  */
+  if (MEM_P (incoming)
+      && (XEXP (incoming, 0) == crtl->args.internal_arg_pointer
+	  || (GET_CODE (XEXP (incoming, 0)) == PLUS
+	      && XEXP (XEXP (incoming, 0), 0)
+		 == crtl->args.internal_arg_pointer
+	      && CONST_INT_P (XEXP (XEXP (incoming, 0), 1)))))
+    {
+      HOST_WIDE_INT off = -FIRST_PARM_OFFSET (current_function_decl);
+      if (GET_CODE (XEXP (incoming, 0)) == PLUS)
+	off += INTVAL (XEXP (XEXP (incoming, 0), 1));
+      incoming
+	= replace_equiv_address_nv (incoming,
+				    plus_constant (Pmode,
+						   arg_pointer_rtx, off));
+    }
+
+#ifdef HAVE_window_save
+  /* DECL_INCOMING_RTL uses the INCOMING_REGNO of parameter registers.
+     If the target machine has an explicit window save instruction, the
+     actual entry value is the corresponding OUTGOING_REGNO instead.  */
+  if (HAVE_window_save && !crtl->uses_only_leaf_regs)
+    {
+      if (REG_P (incoming)
+	  && HARD_REGISTER_P (incoming)
+	  && OUTGOING_REGNO (REGNO (incoming)) != REGNO (incoming))
+	{
+	  parm_reg_t p;
+	  p.incoming = incoming;
+	  incoming
+	    = gen_rtx_REG_offset (incoming, GET_MODE (incoming),
+				  OUTGOING_REGNO (REGNO (incoming)), 0);
+	  p.outgoing = incoming;
+	  vec_safe_push (windowed_parm_regs, p);
+	}
+      else if (GET_CODE (incoming) == PARALLEL)
+	{
+	  rtx outgoing
+	    = gen_rtx_PARALLEL (VOIDmode, rtvec_alloc (XVECLEN (incoming, 0)));
+	  int i;
+
+	  for (i = 0; i < XVECLEN (incoming, 0); i++)
+	    {
+	      rtx reg = XEXP (XVECEXP (incoming, 0, i), 0);
+	      parm_reg_t p;
+	      p.incoming = reg;
+	      reg = gen_rtx_REG_offset (reg, GET_MODE (reg),
+					OUTGOING_REGNO (REGNO (reg)), 0);
+	      p.outgoing = reg;
+	      XVECEXP (outgoing, 0, i)
+		= gen_rtx_EXPR_LIST (VOIDmode, reg,
+				     XEXP (XVECEXP (incoming, 0, i), 1));
+	      vec_safe_push (windowed_parm_regs, p);
+	    }
+
+	  incoming = outgoing;
+	}
+      else if (MEM_P (incoming)
+	       && REG_P (XEXP (incoming, 0))
+	       && HARD_REGISTER_P (XEXP (incoming, 0)))
+	{
+	  rtx reg = XEXP (incoming, 0);
+	  if (OUTGOING_REGNO (REGNO (reg)) != REGNO (reg))
+	    {
+	      parm_reg_t p;
+	      p.incoming = reg;
+	      reg = gen_raw_REG (GET_MODE (reg), OUTGOING_REGNO (REGNO (reg)));
+	      p.outgoing = reg;
+	      vec_safe_push (windowed_parm_regs, p);
+	      incoming = replace_equiv_address_nv (incoming, reg);
+	    }
+	}
+    }
+#endif
+
+  if (!vt_get_decl_and_offset (incoming, &decl, &offset))
+    {
+      if (MEM_P (incoming))
+	{
+	  /* This means argument is passed by invisible reference.  */
+	  offset = 0;
+	  decl = parm;
+	}
+      else
+	{
+	  if (!vt_get_decl_and_offset (decl_rtl, &decl, &offset))
+	    return;
+	  offset += byte_lowpart_offset (GET_MODE (incoming),
+					 GET_MODE (decl_rtl));
+	}
+    }
+
+  if (!decl)
+    return;
+
+  if (parm != decl)
+    {
+      /* If that DECL_RTL wasn't a pseudo that got spilled to
+	 memory, bail out.  Otherwise, the spill slot sharing code
+	 will force the memory to reference spill_slot_decl (%sfp),
+	 so we don't match above.  That's ok, the pseudo must have
+	 referenced the entire parameter, so just reset OFFSET.  */
+      if (decl != get_spill_slot_decl (false))
+        return;
+      offset = 0;
+    }
+
+  if (!track_loc_p (incoming, parm, offset, false, &mode, &offset))
+    return;
+
+  out = &VTI (ENTRY_BLOCK_PTR_FOR_FN (cfun))->out;
+
+  dv = dv_from_decl (parm);
+
+  if (target_for_debug_bind (parm)
+      /* We can't deal with these right now, because this kind of
+	 variable is single-part.  ??? We could handle parallels
+	 that describe multiple locations for the same single
+	 value, but ATM we don't.  */
+      && GET_CODE (incoming) != PARALLEL)
+    {
+      cselib_val *val;
+      rtx lowpart;
+
+      /* ??? We shouldn't ever hit this, but it may happen because
+	 arguments passed by invisible reference aren't dealt with
+	 above: incoming-rtl will have Pmode rather than the
+	 expected mode for the type.  */
+      if (offset)
+	return;
+
+      lowpart = var_lowpart (mode, incoming);
+      if (!lowpart)
+	return;
+
+      val = cselib_lookup_from_insn (lowpart, mode, true,
+				     VOIDmode, get_insns ());
+
+      /* ??? Float-typed values in memory are not handled by
+	 cselib.  */
+      if (val)
+	{
+	  preserve_value (val);
+	  set_variable_part (out, val->val_rtx, dv, offset,
+			     VAR_INIT_STATUS_INITIALIZED, NULL, INSERT);
+	  dv = dv_from_value (val->val_rtx);
+	}
+
+      if (MEM_P (incoming))
+	{
+	  val = cselib_lookup_from_insn (XEXP (incoming, 0), mode, true,
+					 VOIDmode, get_insns ());
+	  if (val)
+	    {
+	      preserve_value (val);
+	      incoming = replace_equiv_address_nv (incoming, val->val_rtx);
+	    }
+	}
+    }
+
+  if (REG_P (incoming))
+    {
+      incoming = var_lowpart (mode, incoming);
+      gcc_assert (REGNO (incoming) < FIRST_PSEUDO_REGISTER);
+      attrs_list_insert (&out->regs[REGNO (incoming)], dv, offset,
+			 incoming);
+      set_variable_part (out, incoming, dv, offset,
+			 VAR_INIT_STATUS_INITIALIZED, NULL, INSERT);
+      if (dv_is_value_p (dv))
+	{
+	  record_entry_value (CSELIB_VAL_PTR (dv_as_value (dv)), incoming);
+	  if (TREE_CODE (TREE_TYPE (parm)) == REFERENCE_TYPE
+	      && INTEGRAL_TYPE_P (TREE_TYPE (TREE_TYPE (parm))))
+	    {
+	      enum machine_mode indmode
+		= TYPE_MODE (TREE_TYPE (TREE_TYPE (parm)));
+	      rtx mem = gen_rtx_MEM (indmode, incoming);
+	      cselib_val *val = cselib_lookup_from_insn (mem, indmode, true,
+							 VOIDmode,
+							 get_insns ());
+	      if (val)
+		{
+		  preserve_value (val);
+		  record_entry_value (val, mem);
+		  set_variable_part (out, mem, dv_from_value (val->val_rtx), 0,
+				     VAR_INIT_STATUS_INITIALIZED, NULL, INSERT);
+		}
+	    }
+	}
+    }
+  else if (GET_CODE (incoming) == PARALLEL && !dv_onepart_p (dv))
+    {
+      int i;
+
+      for (i = 0; i < XVECLEN (incoming, 0); i++)
+	{
+	  rtx reg = XEXP (XVECEXP (incoming, 0, i), 0);
+	  offset = REG_OFFSET (reg);
+	  gcc_assert (REGNO (reg) < FIRST_PSEUDO_REGISTER);
+	  attrs_list_insert (&out->regs[REGNO (reg)], dv, offset, reg);
+	  set_variable_part (out, reg, dv, offset,
+			     VAR_INIT_STATUS_INITIALIZED, NULL, INSERT);
+	}
+    }
+  else if (MEM_P (incoming))
+    {
+      incoming = var_lowpart (mode, incoming);
+      set_variable_part (out, incoming, dv, offset,
+			 VAR_INIT_STATUS_INITIALIZED, NULL, INSERT);
+    }
+}
+
+/* Insert function parameters to IN and OUT sets of ENTRY_BLOCK.  */
+
+static void
+vt_add_function_parameters (void)
+{
+  tree parm;
+
+  for (parm = DECL_ARGUMENTS (current_function_decl);
+       parm; parm = DECL_CHAIN (parm))
+    vt_add_function_parameter (parm);
+
+  if (DECL_HAS_VALUE_EXPR_P (DECL_RESULT (current_function_decl)))
+    {
+      tree vexpr = DECL_VALUE_EXPR (DECL_RESULT (current_function_decl));
+
+      if (TREE_CODE (vexpr) == INDIRECT_REF)
+	vexpr = TREE_OPERAND (vexpr, 0);
+
+      if (TREE_CODE (vexpr) == PARM_DECL
+	  && DECL_ARTIFICIAL (vexpr)
+	  && !DECL_IGNORED_P (vexpr)
+	  && DECL_NAMELESS (vexpr))
+	vt_add_function_parameter (vexpr);
+    }
+}
+
+/* Initialize cfa_base_rtx, create a preserved VALUE for it and
+   ensure it isn't flushed during cselib_reset_table.
+   Can be called only if frame_pointer_rtx resp. arg_pointer_rtx
+   has been eliminated.  */
+
+static void
+vt_init_cfa_base (void)
+{
+  cselib_val *val;
+
+#ifdef FRAME_POINTER_CFA_OFFSET
+  cfa_base_rtx = frame_pointer_rtx;
+  cfa_base_offset = -FRAME_POINTER_CFA_OFFSET (current_function_decl);
+#else
+  cfa_base_rtx = arg_pointer_rtx;
+  cfa_base_offset = -ARG_POINTER_CFA_OFFSET (current_function_decl);
+#endif
+  if (cfa_base_rtx == hard_frame_pointer_rtx
+      || !fixed_regs[REGNO (cfa_base_rtx)])
+    {
+      cfa_base_rtx = NULL_RTX;
+      return;
+    }
+  if (!MAY_HAVE_DEBUG_INSNS)
+    return;
+
+  /* Tell alias analysis that cfa_base_rtx should share
+     find_base_term value with stack pointer or hard frame pointer.  */
+  if (!frame_pointer_needed)
+    vt_equate_reg_base_value (cfa_base_rtx, stack_pointer_rtx);
+  else if (!crtl->stack_realign_tried)
+    vt_equate_reg_base_value (cfa_base_rtx, hard_frame_pointer_rtx);
+
+  val = cselib_lookup_from_insn (cfa_base_rtx, GET_MODE (cfa_base_rtx), 1,
+				 VOIDmode, get_insns ());
+  preserve_value (val);
+  cselib_preserve_cfa_base_value (val, REGNO (cfa_base_rtx));
+}
+
+/* Allocate and initialize the data structures for variable tracking
+   and parse the RTL to get the micro operations.  */
+
+static bool
+vt_initialize (void)
+{
+  basic_block bb;
+  HOST_WIDE_INT fp_cfa_offset = -1;
+
+  alloc_aux_for_blocks (sizeof (struct variable_tracking_info_def));
+
+  attrs_pool = create_alloc_pool ("attrs_def pool",
+				  sizeof (struct attrs_def), 1024);
+  var_pool = create_alloc_pool ("variable_def pool",
+				sizeof (struct variable_def)
+				+ (MAX_VAR_PARTS - 1)
+				* sizeof (((variable)NULL)->var_part[0]), 64);
+  loc_chain_pool = create_alloc_pool ("location_chain_def pool",
+				      sizeof (struct location_chain_def),
+				      1024);
+  shared_hash_pool = create_alloc_pool ("shared_hash_def pool",
+					sizeof (struct shared_hash_def), 256);
+  empty_shared_hash = (shared_hash) pool_alloc (shared_hash_pool);
+  empty_shared_hash->refcount = 1;
+  empty_shared_hash->htab.create (1);
+  changed_variables.create (10);
+
+  /* Init the IN and OUT sets.  */
+  FOR_ALL_BB_FN (bb, cfun)
+    {
+      VTI (bb)->visited = false;
+      VTI (bb)->flooded = false;
+      dataflow_set_init (&VTI (bb)->in);
+      dataflow_set_init (&VTI (bb)->out);
+      VTI (bb)->permp = NULL;
+    }
+
+  if (MAY_HAVE_DEBUG_INSNS)
+    {
+      cselib_init (CSELIB_RECORD_MEMORY | CSELIB_PRESERVE_CONSTANTS);
+      scratch_regs = BITMAP_ALLOC (NULL);
+      valvar_pool = create_alloc_pool ("small variable_def pool",
+				       sizeof (struct variable_def), 256);
+      preserved_values.create (256);
+      global_get_addr_cache = pointer_map_create ();
+    }
+  else
+    {
+      scratch_regs = NULL;
+      valvar_pool = NULL;
+      global_get_addr_cache = NULL;
+    }
+
+  if (MAY_HAVE_DEBUG_INSNS)
+    {
+      rtx reg, expr;
+      int ofst;
+      cselib_val *val;
+
+#ifdef FRAME_POINTER_CFA_OFFSET
+      reg = frame_pointer_rtx;
+      ofst = FRAME_POINTER_CFA_OFFSET (current_function_decl);
+#else
+      reg = arg_pointer_rtx;
+      ofst = ARG_POINTER_CFA_OFFSET (current_function_decl);
+#endif
+
+      ofst -= INCOMING_FRAME_SP_OFFSET;
+
+      val = cselib_lookup_from_insn (reg, GET_MODE (reg), 1,
+				     VOIDmode, get_insns ());
+      preserve_value (val);
+      if (reg != hard_frame_pointer_rtx && fixed_regs[REGNO (reg)])
+	cselib_preserve_cfa_base_value (val, REGNO (reg));
+      expr = plus_constant (GET_MODE (stack_pointer_rtx),
+			    stack_pointer_rtx, -ofst);
+      cselib_add_permanent_equiv (val, expr, get_insns ());
+
+      if (ofst)
+	{
+	  val = cselib_lookup_from_insn (stack_pointer_rtx,
+					 GET_MODE (stack_pointer_rtx), 1,
+					 VOIDmode, get_insns ());
+	  preserve_value (val);
+	  expr = plus_constant (GET_MODE (reg), reg, ofst);
+	  cselib_add_permanent_equiv (val, expr, get_insns ());
+	}
+    }
+
+  /* In order to factor out the adjustments made to the stack pointer or to
+     the hard frame pointer and thus be able to use DW_OP_fbreg operations
+     instead of individual location lists, we're going to rewrite MEMs based
+     on them into MEMs based on the CFA by de-eliminating stack_pointer_rtx
+     or hard_frame_pointer_rtx to the virtual CFA pointer frame_pointer_rtx
+     resp. arg_pointer_rtx.  We can do this either when there is no frame
+     pointer in the function and stack adjustments are consistent for all
+     basic blocks or when there is a frame pointer and no stack realignment.
+     But we first have to check that frame_pointer_rtx resp. arg_pointer_rtx
+     has been eliminated.  */
+  if (!frame_pointer_needed)
+    {
+      rtx reg, elim;
+
+      if (!vt_stack_adjustments ())
+	return false;
+
+#ifdef FRAME_POINTER_CFA_OFFSET
+      reg = frame_pointer_rtx;
+#else
+      reg = arg_pointer_rtx;
+#endif
+      elim = eliminate_regs (reg, VOIDmode, NULL_RTX);
+      if (elim != reg)
+	{
+	  if (GET_CODE (elim) == PLUS)
+	    elim = XEXP (elim, 0);
+	  if (elim == stack_pointer_rtx)
+	    vt_init_cfa_base ();
+	}
+    }
+  else if (!crtl->stack_realign_tried)
+    {
+      rtx reg, elim;
+
+#ifdef FRAME_POINTER_CFA_OFFSET
+      reg = frame_pointer_rtx;
+      fp_cfa_offset = FRAME_POINTER_CFA_OFFSET (current_function_decl);
+#else
+      reg = arg_pointer_rtx;
+      fp_cfa_offset = ARG_POINTER_CFA_OFFSET (current_function_decl);
+#endif
+      elim = eliminate_regs (reg, VOIDmode, NULL_RTX);
+      if (elim != reg)
+	{
+	  if (GET_CODE (elim) == PLUS)
+	    {
+	      fp_cfa_offset -= INTVAL (XEXP (elim, 1));
+	      elim = XEXP (elim, 0);
+	    }
+	  if (elim != hard_frame_pointer_rtx)
+	    fp_cfa_offset = -1;
+	}
+      else
+	fp_cfa_offset = -1;
+    }
+
+  /* If the stack is realigned and a DRAP register is used, we're going to
+     rewrite MEMs based on it representing incoming locations of parameters
+     passed on the stack into MEMs based on the argument pointer.  Although
+     we aren't going to rewrite other MEMs, we still need to initialize the
+     virtual CFA pointer in order to ensure that the argument pointer will
+     be seen as a constant throughout the function.
+
+     ??? This doesn't work if FRAME_POINTER_CFA_OFFSET is defined.  */
+  else if (stack_realign_drap)
+    {
+      rtx reg, elim;
+
+#ifdef FRAME_POINTER_CFA_OFFSET
+      reg = frame_pointer_rtx;
+#else
+      reg = arg_pointer_rtx;
+#endif
+      elim = eliminate_regs (reg, VOIDmode, NULL_RTX);
+      if (elim != reg)
+	{
+	  if (GET_CODE (elim) == PLUS)
+	    elim = XEXP (elim, 0);
+	  if (elim == hard_frame_pointer_rtx)
+	    vt_init_cfa_base ();
+	}
+    }
+
+  hard_frame_pointer_adjustment = -1;
+
+  vt_add_function_parameters ();
+
+  FOR_EACH_BB_FN (bb, cfun)
+    {
+      rtx insn;
+      HOST_WIDE_INT pre, post = 0;
+      basic_block first_bb, last_bb;
+
+      if (MAY_HAVE_DEBUG_INSNS)
+	{
+	  cselib_record_sets_hook = add_with_sets;
+	  if (dump_file && (dump_flags & TDF_DETAILS))
+	    fprintf (dump_file, "first value: %i\n",
+		     cselib_get_next_uid ());
+	}
+
+      first_bb = bb;
+      for (;;)
+	{
+	  edge e;
+	  if (bb->next_bb == EXIT_BLOCK_PTR_FOR_FN (cfun)
+	      || ! single_pred_p (bb->next_bb))
+	    break;
+	  e = find_edge (bb, bb->next_bb);
+	  if (! e || (e->flags & EDGE_FALLTHRU) == 0)
+	    break;
+	  bb = bb->next_bb;
+	}
+      last_bb = bb;
+
+      /* Add the micro-operations to the vector.  */
+      FOR_BB_BETWEEN (bb, first_bb, last_bb->next_bb, next_bb)
+	{
+	  HOST_WIDE_INT offset = VTI (bb)->out.stack_adjust;
+	  VTI (bb)->out.stack_adjust = VTI (bb)->in.stack_adjust;
+	  for (insn = BB_HEAD (bb); insn != NEXT_INSN (BB_END (bb));
+	       insn = NEXT_INSN (insn))
+	    {
+	      if (INSN_P (insn))
+		{
+		  if (!frame_pointer_needed)
+		    {
+		      insn_stack_adjust_offset_pre_post (insn, &pre, &post);
+		      if (pre)
+			{
+			  micro_operation mo;
+			  mo.type = MO_ADJUST;
+			  mo.u.adjust = pre;
+			  mo.insn = insn;
+			  if (dump_file && (dump_flags & TDF_DETAILS))
+			    log_op_type (PATTERN (insn), bb, insn,
+					 MO_ADJUST, dump_file);
+			  VTI (bb)->mos.safe_push (mo);
+			  VTI (bb)->out.stack_adjust += pre;
+			}
+		    }
+
+		  cselib_hook_called = false;
+		  adjust_insn (bb, insn);
+		  if (MAY_HAVE_DEBUG_INSNS)
+		    {
+		      if (CALL_P (insn))
+			prepare_call_arguments (bb, insn);
+		      cselib_process_insn (insn);
+		      if (dump_file && (dump_flags & TDF_DETAILS))
+			{
+			  print_rtl_single (dump_file, insn);
+			  dump_cselib_table (dump_file);
+			}
+		    }
+		  if (!cselib_hook_called)
+		    add_with_sets (insn, 0, 0);
+		  cancel_changes (0);
+
+		  if (!frame_pointer_needed && post)
+		    {
+		      micro_operation mo;
+		      mo.type = MO_ADJUST;
+		      mo.u.adjust = post;
+		      mo.insn = insn;
+		      if (dump_file && (dump_flags & TDF_DETAILS))
+			log_op_type (PATTERN (insn), bb, insn,
+				     MO_ADJUST, dump_file);
+		      VTI (bb)->mos.safe_push (mo);
+		      VTI (bb)->out.stack_adjust += post;
+		    }
+
+		  if (fp_cfa_offset != -1
+		      && hard_frame_pointer_adjustment == -1
+		      && fp_setter_insn (insn))
+		    {
+		      vt_init_cfa_base ();
+		      hard_frame_pointer_adjustment = fp_cfa_offset;
+		      /* Disassociate sp from fp now.  */
+		      if (MAY_HAVE_DEBUG_INSNS)
+			{
+			  cselib_val *v;
+			  cselib_invalidate_rtx (stack_pointer_rtx);
+			  v = cselib_lookup (stack_pointer_rtx, Pmode, 1,
+					     VOIDmode);
+			  if (v && !cselib_preserved_value_p (v))
+			    {
+			      cselib_set_value_sp_based (v);
+			      preserve_value (v);
+			    }
+			}
+		    }
+		}
+	    }
+	  gcc_assert (offset == VTI (bb)->out.stack_adjust);
+	}
+
+      bb = last_bb;
+
+      if (MAY_HAVE_DEBUG_INSNS)
+	{
+	  cselib_preserve_only_values ();
+	  cselib_reset_table (cselib_get_next_uid ());
+	  cselib_record_sets_hook = NULL;
+	}
+    }
+
+  hard_frame_pointer_adjustment = -1;
+  VTI (ENTRY_BLOCK_PTR_FOR_FN (cfun))->flooded = true;
+  cfa_base_rtx = NULL_RTX;
+  return true;
+}
+
+/* This is *not* reset after each function.  It gives each
+   NOTE_INSN_DELETED_DEBUG_LABEL in the entire compilation
+   a unique label number.  */
+
+static int debug_label_num = 1;
+
+/* Get rid of all debug insns from the insn stream.  */
+
+static void
+delete_debug_insns (void)
+{
+  basic_block bb;
+  rtx insn, next;
+
+  if (!MAY_HAVE_DEBUG_INSNS)
+    return;
+
+  FOR_EACH_BB_FN (bb, cfun)
+    {
+      FOR_BB_INSNS_SAFE (bb, insn, next)
+	if (DEBUG_INSN_P (insn))
+	  {
+	    tree decl = INSN_VAR_LOCATION_DECL (insn);
+	    if (TREE_CODE (decl) == LABEL_DECL
+		&& DECL_NAME (decl)
+		&& !DECL_RTL_SET_P (decl))
+	      {
+		PUT_CODE (insn, NOTE);
+		NOTE_KIND (insn) = NOTE_INSN_DELETED_DEBUG_LABEL;
+		NOTE_DELETED_LABEL_NAME (insn)
+		  = IDENTIFIER_POINTER (DECL_NAME (decl));
+		SET_DECL_RTL (decl, insn);
+		CODE_LABEL_NUMBER (insn) = debug_label_num++;
+	      }
+	    else
+	      delete_insn (insn);
+	  }
+    }
+}
+
+/* Run a fast, BB-local only version of var tracking, to take care of
+   information that we don't do global analysis on, such that not all
+   information is lost.  If SKIPPED holds, we're skipping the global
+   pass entirely, so we should try to use information it would have
+   handled as well..  */
+
+static void
+vt_debug_insns_local (bool skipped ATTRIBUTE_UNUSED)
+{
+  /* ??? Just skip it all for now.  */
+  delete_debug_insns ();
+}
+
+/* Free the data structures needed for variable tracking.  */
+
+static void
+vt_finalize (void)
+{
+  basic_block bb;
+
+  FOR_EACH_BB_FN (bb, cfun)
+    {
+      VTI (bb)->mos.release ();
+    }
+
+  FOR_ALL_BB_FN (bb, cfun)
+    {
+      dataflow_set_destroy (&VTI (bb)->in);
+      dataflow_set_destroy (&VTI (bb)->out);
+      if (VTI (bb)->permp)
+	{
+	  dataflow_set_destroy (VTI (bb)->permp);
+	  XDELETE (VTI (bb)->permp);
+	}
+    }
+  free_aux_for_blocks ();
+  empty_shared_hash->htab.dispose ();
+  changed_variables.dispose ();
+  free_alloc_pool (attrs_pool);
+  free_alloc_pool (var_pool);
+  free_alloc_pool (loc_chain_pool);
+  free_alloc_pool (shared_hash_pool);
+
+  if (MAY_HAVE_DEBUG_INSNS)
+    {
+      if (global_get_addr_cache)
+	pointer_map_destroy (global_get_addr_cache);
+      global_get_addr_cache = NULL;
+      if (loc_exp_dep_pool)
+	free_alloc_pool (loc_exp_dep_pool);
+      loc_exp_dep_pool = NULL;
+      free_alloc_pool (valvar_pool);
+      preserved_values.release ();
+      cselib_finish ();
+      BITMAP_FREE (scratch_regs);
+      scratch_regs = NULL;
+    }
+
+#ifdef HAVE_window_save
+  vec_free (windowed_parm_regs);
+#endif
+
+  if (vui_vec)
+    XDELETEVEC (vui_vec);
+  vui_vec = NULL;
+  vui_allocated = 0;
+}
+
+/* The entry point to variable tracking pass.  */
+
+static inline unsigned int
+variable_tracking_main_1 (void)
+{
+  bool success;
+
+  if (flag_var_tracking_assignments < 0)
+    {
+      delete_debug_insns ();
+      return 0;
+    }
+
+  if (n_basic_blocks_for_fn (cfun) > 500 &&
+      n_edges_for_fn (cfun) / n_basic_blocks_for_fn (cfun) >= 20)
+    {
+      vt_debug_insns_local (true);
+      return 0;
+    }
+
+  mark_dfs_back_edges ();
+  if (!vt_initialize ())
+    {
+      vt_finalize ();
+      vt_debug_insns_local (true);
+      return 0;
+    }
+
+  success = vt_find_locations ();
+
+  if (!success && flag_var_tracking_assignments > 0)
+    {
+      vt_finalize ();
+
+      delete_debug_insns ();
+
+      /* This is later restored by our caller.  */
+      flag_var_tracking_assignments = 0;
+
+      success = vt_initialize ();
+      gcc_assert (success);
+
+      success = vt_find_locations ();
+    }
+
+  if (!success)
+    {
+      vt_finalize ();
+      vt_debug_insns_local (false);
+      return 0;
+    }
+
+  if (dump_file && (dump_flags & TDF_DETAILS))
+    {
+      dump_dataflow_sets ();
+      dump_reg_info (dump_file);
+      dump_flow_info (dump_file, dump_flags);
+    }
+
+  timevar_push (TV_VAR_TRACKING_EMIT);
+  vt_emit_notes ();
+  timevar_pop (TV_VAR_TRACKING_EMIT);
+
+  vt_finalize ();
+  vt_debug_insns_local (false);
+  return 0;
+}
+
+unsigned int
+variable_tracking_main (void)
+{
+  unsigned int ret;
+  int save = flag_var_tracking_assignments;
+
+  ret = variable_tracking_main_1 ();
+
+  flag_var_tracking_assignments = save;
+
+  return ret;
+}
+
+static bool
+gate_handle_var_tracking (void)
+{
+  return (flag_var_tracking && !targetm.delay_vartrack);
+}
+
+
+
+namespace {
+
+const pass_data pass_data_variable_tracking =
+{
+  RTL_PASS, /* type */
+  "vartrack", /* name */
+  OPTGROUP_NONE, /* optinfo_flags */
+  true, /* has_gate */
+  true, /* has_execute */
+  TV_VAR_TRACKING, /* tv_id */
+  0, /* properties_required */
+  0, /* properties_provided */
+  0, /* properties_destroyed */
+  0, /* todo_flags_start */
+  ( TODO_verify_rtl_sharing | TODO_verify_flow ), /* todo_flags_finish */
+};
+
+class pass_variable_tracking : public rtl_opt_pass
+{
+public:
+  pass_variable_tracking (gcc::context *ctxt)
+    : rtl_opt_pass (pass_data_variable_tracking, ctxt)
+  {}
+
+  /* opt_pass methods: */
+  bool gate () { return gate_handle_var_tracking (); }
+  unsigned int execute () { return variable_tracking_main (); }
+
+}; // class pass_variable_tracking
+
+} // anon namespace
+
+rtl_opt_pass *
+make_pass_variable_tracking (gcc::context *ctxt)
+{
+  return new pass_variable_tracking (ctxt);
+}