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verified gcc-4.6.4.tar.bz2.sig;
imported gcc-4.6.4 source tree from verified upstream tarball.

downloading a git-generated archive based on the 'upstream' tag
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however, do note that line-endings of files in your working
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1 files changed, 1140 insertions, 0 deletions

diff --git a/gcc/read-rtl.c b/gcc/read-rtl.c
new file mode 100644
index 000000000..1402c5468
--- /dev/null
+++ b/gcc/read-rtl.c
@@ -0,0 +1,1140 @@
+/* RTL reader for GCC.
+   Copyright (C) 1987, 1988, 1991, 1994, 1997, 1998, 1999, 2000, 2001, 2002,
+   2003, 2004, 2005, 2007, 2008, 2010
+   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/>.  */
+
+#include "bconfig.h"
+
+/* Disable rtl checking; it conflicts with the iterator handling.  */
+#undef ENABLE_RTL_CHECKING
+
+#include "system.h"
+#include "coretypes.h"
+#include "tm.h"
+#include "rtl.h"
+#include "obstack.h"
+#include "hashtab.h"
+#include "read-md.h"
+#include "gensupport.h"
+
+/* One element in a singly-linked list of (integer, string) pairs.  */
+struct map_value {
+  struct map_value *next;
+  int number;
+  const char *string;
+};
+
+/* Maps an iterator or attribute name to a list of (integer, string) pairs.
+   The integers are mode or code values; the strings are either C conditions
+   or attribute values.  */
+struct mapping {
+  /* The name of the iterator or attribute.  */
+  const char *name;
+
+  /* The group (modes or codes) to which the iterator or attribute belongs.  */
+  struct iterator_group *group;
+
+  /* Gives a unique number to the attribute or iterator.  Numbers are
+     allocated consecutively, starting at 0.  */
+  int index;
+
+  /* The list of (integer, string) pairs.  */
+  struct map_value *values;
+};
+
+/* A structure for abstracting the common parts of code and mode iterators.  */
+struct iterator_group {
+  /* Tables of "mapping" structures, one for attributes and one for iterators.  */
+  htab_t attrs, iterators;
+
+  /* The number of "real" modes or codes (and by extension, the first
+     number available for use as an iterator placeholder).  */
+  int num_builtins;
+
+  /* Treat the given string as the name of a standard mode or code and
+     return its integer value.  */
+  int (*find_builtin) (const char *);
+
+  /* Return true if the given rtx uses the given mode or code.  */
+  bool (*uses_iterator_p) (rtx, int);
+
+  /* Make the given rtx use the given mode or code.  */
+  void (*apply_iterator) (rtx, int);
+};
+
+/* A structure used to pass data from read_rtx to apply_iterator_traverse
+   via htab_traverse.  */
+struct iterator_traverse_data {
+  /* Instruction queue.  */
+  rtx queue;
+  /* Attributes seen for modes.  */
+  struct map_value *mode_maps;
+  /* The last unknown attribute used as a mode.  */
+  const char *unknown_mode_attr;
+};
+
+/* If CODE is the number of a code iterator, return a real rtx code that
+   has the same format.  Return CODE otherwise.  */
+#define BELLWETHER_CODE(CODE) \
+  ((CODE) < NUM_RTX_CODE ? CODE : bellwether_codes[CODE - NUM_RTX_CODE])
+
+static int find_mode (const char *);
+static bool uses_mode_iterator_p (rtx, int);
+static void apply_mode_iterator (rtx, int);
+static int find_code (const char *);
+static bool uses_code_iterator_p (rtx, int);
+static void apply_code_iterator (rtx, int);
+static const char *apply_iterator_to_string (const char *, struct mapping *, int);
+static rtx apply_iterator_to_rtx (rtx, struct mapping *, int,
+				  struct map_value *, const char **);
+static bool uses_iterator_p (rtx, struct mapping *);
+static const char *add_condition_to_string (const char *, const char *);
+static void add_condition_to_rtx (rtx, const char *);
+static int apply_iterator_traverse (void **, void *);
+static struct mapping *add_mapping (struct iterator_group *, htab_t t,
+				    const char *);
+static struct map_value **add_map_value (struct map_value **,
+					 int, const char *);
+static void initialize_iterators (void);
+static void read_conditions (void);
+static void validate_const_int (const char *);
+static int find_iterator (struct iterator_group *, const char *);
+static struct mapping *read_mapping (struct iterator_group *, htab_t);
+static void check_code_iterator (struct mapping *);
+static rtx read_rtx_code (const char *, struct map_value **);
+static rtx read_nested_rtx (struct map_value **);
+static rtx read_rtx_variadic (struct map_value **, rtx);
+
+/* The mode and code iterator structures.  */
+static struct iterator_group modes, codes;
+
+/* Index I is the value of BELLWETHER_CODE (I + NUM_RTX_CODE).  */
+static enum rtx_code *bellwether_codes;
+
+/* Implementations of the iterator_group callbacks for modes.  */
+
+static int
+find_mode (const char *name)
+{
+  int i;
+
+  for (i = 0; i < NUM_MACHINE_MODES; i++)
+    if (strcmp (GET_MODE_NAME (i), name) == 0)
+      return i;
+
+  fatal_with_file_and_line ("unknown mode `%s'", name);
+}
+
+static bool
+uses_mode_iterator_p (rtx x, int mode)
+{
+  return (int) GET_MODE (x) == mode;
+}
+
+static void
+apply_mode_iterator (rtx x, int mode)
+{
+  PUT_MODE (x, (enum machine_mode) mode);
+}
+
+/* Implementations of the iterator_group callbacks for codes.  */
+
+static int
+find_code (const char *name)
+{
+  int i;
+
+  for (i = 0; i < NUM_RTX_CODE; i++)
+    if (strcmp (GET_RTX_NAME (i), name) == 0)
+      return i;
+
+  fatal_with_file_and_line ("unknown rtx code `%s'", name);
+}
+
+static bool
+uses_code_iterator_p (rtx x, int code)
+{
+  return (int) GET_CODE (x) == code;
+}
+
+static void
+apply_code_iterator (rtx x, int code)
+{
+  PUT_CODE (x, (enum rtx_code) code);
+}
+
+/* Map a code or mode attribute string P to the underlying string for
+   ITERATOR and VALUE.  */
+
+static struct map_value *
+map_attr_string (const char *p, struct mapping *iterator, int value)
+{
+  const char *attr;
+  struct mapping *m;
+  struct map_value *v;
+
+  /* If there's a "iterator:" prefix, check whether the iterator name matches.
+     Set ATTR to the start of the attribute name.  */
+  attr = strchr (p, ':');
+  if (attr == 0)
+    attr = p;
+  else
+    {
+      if (strncmp (p, iterator->name, attr - p) != 0
+	  || iterator->name[attr - p] != 0)
+	return 0;
+      attr++;
+    }
+
+  /* Find the attribute specification.  */
+  m = (struct mapping *) htab_find (iterator->group->attrs, &attr);
+  if (m == 0)
+    return 0;
+
+  /* Find the attribute value for VALUE.  */
+  for (v = m->values; v != 0; v = v->next)
+    if (v->number == value)
+      break;
+
+  return v;
+}
+
+/* Given an attribute string used as a machine mode, return an index
+   to store in the machine mode to be translated by
+   apply_iterator_to_rtx.  */
+
+static unsigned int
+mode_attr_index (struct map_value **mode_maps, const char *string)
+{
+  char *p;
+  struct map_value *mv;
+
+  /* Copy the attribute string into permanent storage, without the
+     angle brackets around it.  */
+  obstack_grow0 (&string_obstack, string + 1, strlen (string) - 2);
+  p = XOBFINISH (&string_obstack, char *);
+
+  mv = XNEW (struct map_value);
+  mv->number = *mode_maps == 0 ? 0 : (*mode_maps)->number + 1;
+  mv->string = p;
+  mv->next = *mode_maps;
+  *mode_maps = mv;
+
+  /* We return a code which we can map back into this string: the
+     number of machine modes + the number of mode iterators + the index
+     we just used.  */
+  return MAX_MACHINE_MODE + htab_elements (modes.iterators) + mv->number;
+}
+
+/* Apply MODE_MAPS to the top level of X, expanding cases where an
+   attribute is used for a mode.  ITERATOR is the current iterator we are
+   expanding, and VALUE is the value to which we are expanding it.
+   This sets *UNKNOWN to true if we find a mode attribute which has not
+   yet been defined, and does not change it otherwise.  */
+
+static void
+apply_mode_maps (rtx x, struct map_value *mode_maps, struct mapping *iterator,
+		 int value, const char **unknown)
+{
+  unsigned int offset;
+  int indx;
+  struct map_value *pm;
+
+  offset = MAX_MACHINE_MODE + htab_elements (modes.iterators);
+  if (GET_MODE (x) < offset)
+    return;
+
+  indx = GET_MODE (x) - offset;
+  for (pm = mode_maps; pm; pm = pm->next)
+    {
+      if (pm->number == indx)
+	{
+	  struct map_value *v;
+
+	  v = map_attr_string (pm->string, iterator, value);
+	  if (v)
+	    PUT_MODE (x, (enum machine_mode) find_mode (v->string));
+	  else
+	    *unknown = pm->string;
+	  return;
+	}
+    }
+}
+
+/* Given that ITERATOR is being expanded as VALUE, apply the appropriate
+   string substitutions to STRING.  Return the new string if any changes
+   were needed, otherwise return STRING itself.  */
+
+static const char *
+apply_iterator_to_string (const char *string, struct mapping *iterator, int value)
+{
+  char *base, *copy, *p, *start, *end;
+  struct map_value *v;
+
+  if (string == 0)
+    return string;
+
+  base = p = copy = ASTRDUP (string);
+  while ((start = strchr (p, '<')) && (end = strchr (start, '>')))
+    {
+      p = start + 1;
+
+      *end = 0;
+      v = map_attr_string (p, iterator, value);
+      *end = '>';
+      if (v == 0)
+	continue;
+
+      /* Add everything between the last copied byte and the '<',
+	 then add in the attribute value.  */
+      obstack_grow (&string_obstack, base, start - base);
+      obstack_grow (&string_obstack, v->string, strlen (v->string));
+      base = end + 1;
+    }
+  if (base != copy)
+    {
+      obstack_grow (&string_obstack, base, strlen (base) + 1);
+      copy = XOBFINISH (&string_obstack, char *);
+      copy_md_ptr_loc (copy, string);
+      return copy;
+    }
+  return string;
+}
+
+/* Return a copy of ORIGINAL in which all uses of ITERATOR have been
+   replaced by VALUE.  MODE_MAPS holds information about attribute
+   strings used for modes.  This sets *UNKNOWN_MODE_ATTR to the value of
+   an unknown mode attribute, and does not change it otherwise.  */
+
+static rtx
+apply_iterator_to_rtx (rtx original, struct mapping *iterator, int value,
+		       struct map_value *mode_maps,
+		       const char **unknown_mode_attr)
+{
+  struct iterator_group *group;
+  const char *format_ptr;
+  int i, j;
+  rtx x;
+  enum rtx_code bellwether_code;
+
+  if (original == 0)
+    return original;
+
+  /* Create a shallow copy of ORIGINAL.  */
+  bellwether_code = BELLWETHER_CODE (GET_CODE (original));
+  x = rtx_alloc (bellwether_code);
+  memcpy (x, original, RTX_CODE_SIZE (bellwether_code));
+
+  /* Change the mode or code itself.  */
+  group = iterator->group;
+  if (group->uses_iterator_p (x, iterator->index + group->num_builtins))
+    group->apply_iterator (x, value);
+
+  if (mode_maps)
+    apply_mode_maps (x, mode_maps, iterator, value, unknown_mode_attr);
+
+  /* Change each string and recursively change each rtx.  */
+  format_ptr = GET_RTX_FORMAT (bellwether_code);
+  for (i = 0; format_ptr[i] != 0; i++)
+    switch (format_ptr[i])
+      {
+      case 'T':
+	XTMPL (x, i) = apply_iterator_to_string (XTMPL (x, i), iterator, value);
+	break;
+
+      case 'S':
+      case 's':
+	XSTR (x, i) = apply_iterator_to_string (XSTR (x, i), iterator, value);
+	break;
+
+      case 'e':
+	XEXP (x, i) = apply_iterator_to_rtx (XEXP (x, i), iterator, value,
+					     mode_maps, unknown_mode_attr);
+	break;
+
+      case 'V':
+      case 'E':
+	if (XVEC (original, i))
+	  {
+	    XVEC (x, i) = rtvec_alloc (XVECLEN (original, i));
+	    for (j = 0; j < XVECLEN (x, i); j++)
+	      XVECEXP (x, i, j) = apply_iterator_to_rtx (XVECEXP (original, i, j),
+							 iterator, value, mode_maps,
+							 unknown_mode_attr);
+	  }
+	break;
+
+      default:
+	break;
+      }
+  return x;
+}
+
+/* Return true if X (or some subexpression of X) uses iterator ITERATOR.  */
+
+static bool
+uses_iterator_p (rtx x, struct mapping *iterator)
+{
+  struct iterator_group *group;
+  const char *format_ptr;
+  int i, j;
+
+  if (x == 0)
+    return false;
+
+  group = iterator->group;
+  if (group->uses_iterator_p (x, iterator->index + group->num_builtins))
+    return true;
+
+  format_ptr = GET_RTX_FORMAT (BELLWETHER_CODE (GET_CODE (x)));
+  for (i = 0; format_ptr[i] != 0; i++)
+    switch (format_ptr[i])
+      {
+      case 'e':
+	if (uses_iterator_p (XEXP (x, i), iterator))
+	  return true;
+	break;
+
+      case 'V':
+      case 'E':
+	if (XVEC (x, i))
+	  for (j = 0; j < XVECLEN (x, i); j++)
+	    if (uses_iterator_p (XVECEXP (x, i, j), iterator))
+	      return true;
+	break;
+
+      default:
+	break;
+      }
+  return false;
+}
+
+/* Return a condition that must satisfy both ORIGINAL and EXTRA.  If ORIGINAL
+   has the form "&& ..." (as used in define_insn_and_splits), assume that
+   EXTRA is already satisfied.  Empty strings are treated like "true".  */
+
+static const char *
+add_condition_to_string (const char *original, const char *extra)
+{
+  if (original != 0 && original[0] == '&' && original[1] == '&')
+    return original;
+  return join_c_conditions (original, extra);
+}
+
+/* Like add_condition, but applied to all conditions in rtx X.  */
+
+static void
+add_condition_to_rtx (rtx x, const char *extra)
+{
+  switch (GET_CODE (x))
+    {
+    case DEFINE_INSN:
+    case DEFINE_EXPAND:
+      XSTR (x, 2) = add_condition_to_string (XSTR (x, 2), extra);
+      break;
+
+    case DEFINE_SPLIT:
+    case DEFINE_PEEPHOLE:
+    case DEFINE_PEEPHOLE2:
+    case DEFINE_COND_EXEC:
+      XSTR (x, 1) = add_condition_to_string (XSTR (x, 1), extra);
+      break;
+
+    case DEFINE_INSN_AND_SPLIT:
+      XSTR (x, 2) = add_condition_to_string (XSTR (x, 2), extra);
+      XSTR (x, 4) = add_condition_to_string (XSTR (x, 4), extra);
+      break;
+
+    default:
+      break;
+    }
+}
+
+/* A htab_traverse callback.  Search the EXPR_LIST given by DATA
+   for rtxes that use the iterator in *SLOT.  Replace each such rtx
+   with a list of expansions.  */
+
+static int
+apply_iterator_traverse (void **slot, void *data)
+{
+  struct iterator_traverse_data *mtd = (struct iterator_traverse_data *) data;
+  struct mapping *iterator;
+  struct map_value *v;
+  rtx elem, new_elem, original, x;
+
+  iterator = (struct mapping *) *slot;
+  for (elem = mtd->queue; elem != 0; elem = XEXP (elem, 1))
+    if (uses_iterator_p (XEXP (elem, 0), iterator))
+      {
+	/* For each iterator we expand, we set UNKNOWN_MODE_ATTR to NULL.
+	   If apply_iterator_rtx finds an unknown attribute for a mode,
+	   it will set it to the attribute.  We want to know whether
+	   the attribute is unknown after we have expanded all
+	   possible iterators, so setting it to NULL here gives us the
+	   right result when the hash table traversal is complete.  */
+	mtd->unknown_mode_attr = NULL;
+
+	original = XEXP (elem, 0);
+	for (v = iterator->values; v != 0; v = v->next)
+	  {
+	    x = apply_iterator_to_rtx (original, iterator, v->number,
+				       mtd->mode_maps,
+				       &mtd->unknown_mode_attr);
+	    add_condition_to_rtx (x, v->string);
+	    if (v != iterator->values)
+	      {
+		/* Insert a new EXPR_LIST node after ELEM and put the
+		   new expansion there.  */
+		new_elem = rtx_alloc (EXPR_LIST);
+		XEXP (new_elem, 1) = XEXP (elem, 1);
+		XEXP (elem, 1) = new_elem;
+		elem = new_elem;
+	      }
+	    XEXP (elem, 0) = x;
+	  }
+    }
+  return 1;
+}
+
+/* Add a new "mapping" structure to hashtable TABLE.  NAME is the name
+   of the mapping and GROUP is the group to which it belongs.  */
+
+static struct mapping *
+add_mapping (struct iterator_group *group, htab_t table, const char *name)
+{
+  struct mapping *m;
+  void **slot;
+
+  m = XNEW (struct mapping);
+  m->name = xstrdup (name);
+  m->group = group;
+  m->index = htab_elements (table);
+  m->values = 0;
+
+  slot = htab_find_slot (table, m, INSERT);
+  if (*slot != 0)
+    fatal_with_file_and_line ("`%s' already defined", name);
+
+  *slot = m;
+  return m;
+}
+
+/* Add the pair (NUMBER, STRING) to a list of map_value structures.
+   END_PTR points to the current null terminator for the list; return
+   a pointer the new null terminator.  */
+
+static struct map_value **
+add_map_value (struct map_value **end_ptr, int number, const char *string)
+{
+  struct map_value *value;
+
+  value = XNEW (struct map_value);
+  value->next = 0;
+  value->number = number;
+  value->string = string;
+
+  *end_ptr = value;
+  return &value->next;
+}
+
+/* Do one-time initialization of the mode and code attributes.  */
+
+static void
+initialize_iterators (void)
+{
+  struct mapping *lower, *upper;
+  struct map_value **lower_ptr, **upper_ptr;
+  char *copy, *p;
+  int i;
+
+  modes.attrs = htab_create (13, leading_string_hash, leading_string_eq_p, 0);
+  modes.iterators = htab_create (13, leading_string_hash,
+				 leading_string_eq_p, 0);
+  modes.num_builtins = MAX_MACHINE_MODE;
+  modes.find_builtin = find_mode;
+  modes.uses_iterator_p = uses_mode_iterator_p;
+  modes.apply_iterator = apply_mode_iterator;
+
+  codes.attrs = htab_create (13, leading_string_hash, leading_string_eq_p, 0);
+  codes.iterators = htab_create (13, leading_string_hash,
+				 leading_string_eq_p, 0);
+  codes.num_builtins = NUM_RTX_CODE;
+  codes.find_builtin = find_code;
+  codes.uses_iterator_p = uses_code_iterator_p;
+  codes.apply_iterator = apply_code_iterator;
+
+  lower = add_mapping (&modes, modes.attrs, "mode");
+  upper = add_mapping (&modes, modes.attrs, "MODE");
+  lower_ptr = &lower->values;
+  upper_ptr = &upper->values;
+  for (i = 0; i < MAX_MACHINE_MODE; i++)
+    {
+      copy = xstrdup (GET_MODE_NAME (i));
+      for (p = copy; *p != 0; p++)
+	*p = TOLOWER (*p);
+
+      upper_ptr = add_map_value (upper_ptr, i, GET_MODE_NAME (i));
+      lower_ptr = add_map_value (lower_ptr, i, copy);
+    }
+
+  lower = add_mapping (&codes, codes.attrs, "code");
+  upper = add_mapping (&codes, codes.attrs, "CODE");
+  lower_ptr = &lower->values;
+  upper_ptr = &upper->values;
+  for (i = 0; i < NUM_RTX_CODE; i++)
+    {
+      copy = xstrdup (GET_RTX_NAME (i));
+      for (p = copy; *p != 0; p++)
+	*p = TOUPPER (*p);
+
+      lower_ptr = add_map_value (lower_ptr, i, GET_RTX_NAME (i));
+      upper_ptr = add_map_value (upper_ptr, i, copy);
+    }
+}
+
+/* Provide a version of a function to read a long long if the system does
+   not provide one.  */
+#if HOST_BITS_PER_WIDE_INT > HOST_BITS_PER_LONG && !defined(HAVE_ATOLL) && !defined(HAVE_ATOQ)
+HOST_WIDE_INT atoll (const char *);
+
+HOST_WIDE_INT
+atoll (const char *p)
+{
+  int neg = 0;
+  HOST_WIDE_INT tmp_wide;
+
+  while (ISSPACE (*p))
+    p++;
+  if (*p == '-')
+    neg = 1, p++;
+  else if (*p == '+')
+    p++;
+
+  tmp_wide = 0;
+  while (ISDIGIT (*p))
+    {
+      HOST_WIDE_INT new_wide = tmp_wide*10 + (*p - '0');
+      if (new_wide < tmp_wide)
+	{
+	  /* Return INT_MAX equiv on overflow.  */
+	  tmp_wide = (~(unsigned HOST_WIDE_INT) 0) >> 1;
+	  break;
+	}
+      tmp_wide = new_wide;
+      p++;
+    }
+
+  if (neg)
+    tmp_wide = -tmp_wide;
+  return tmp_wide;
+}
+#endif
+
+/* Process a define_conditions directive, starting with the optional
+   space after the "define_conditions".  The directive looks like this:
+
+     (define_conditions [
+        (number "string")
+        (number "string")
+        ...
+     ])
+
+   It's not intended to appear in machine descriptions.  It is
+   generated by (the program generated by) genconditions.c, and
+   slipped in at the beginning of the sequence of MD files read by
+   most of the other generators.  */
+static void
+read_conditions (void)
+{
+  int c;
+
+  c = read_skip_spaces ();
+  if (c != '[')
+    fatal_expected_char ('[', c);
+
+  while ( (c = read_skip_spaces ()) != ']')
+    {
+      struct md_name name;
+      char *expr;
+      int value;
+
+      if (c != '(')
+	fatal_expected_char ('(', c);
+
+      read_name (&name);
+      validate_const_int (name.string);
+      value = atoi (name.string);
+
+      c = read_skip_spaces ();
+      if (c != '"')
+	fatal_expected_char ('"', c);
+      expr = read_quoted_string ();
+
+      c = read_skip_spaces ();
+      if (c != ')')
+	fatal_expected_char (')', c);
+
+      add_c_test (expr, value);
+    }
+}
+
+static void
+validate_const_int (const char *string)
+{
+  const char *cp;
+  int valid = 1;
+
+  cp = string;
+  while (*cp && ISSPACE (*cp))
+    cp++;
+  if (*cp == '-' || *cp == '+')
+    cp++;
+  if (*cp == 0)
+    valid = 0;
+  for (; *cp; cp++)
+    if (! ISDIGIT (*cp))
+      valid = 0;
+  if (!valid)
+    fatal_with_file_and_line ("invalid decimal constant \"%s\"\n", string);
+}
+
+/* Search GROUP for a mode or code called NAME and return its numerical
+   identifier.  */
+
+static int
+find_iterator (struct iterator_group *group, const char *name)
+{
+  struct mapping *m;
+
+  m = (struct mapping *) htab_find (group->iterators, &name);
+  if (m != 0)
+    return m->index + group->num_builtins;
+  return group->find_builtin (name);
+}
+
+/* Finish reading a declaration of the form:
+
+       (define... <name> [<value1> ... <valuen>])
+
+   from the MD file, where each <valuei> is either a bare symbol name or a
+   "(<name> <string>)" pair.  The "(define..." part has already been read.
+
+   Represent the declaration as a "mapping" structure; add it to TABLE
+   (which belongs to GROUP) and return it.  */
+
+static struct mapping *
+read_mapping (struct iterator_group *group, htab_t table)
+{
+  struct md_name name;
+  struct mapping *m;
+  struct map_value **end_ptr;
+  const char *string;
+  int number, c;
+
+  /* Read the mapping name and create a structure for it.  */
+  read_name (&name);
+  m = add_mapping (group, table, name.string);
+
+  c = read_skip_spaces ();
+  if (c != '[')
+    fatal_expected_char ('[', c);
+
+  /* Read each value.  */
+  end_ptr = &m->values;
+  c = read_skip_spaces ();
+  do
+    {
+      if (c != '(')
+	{
+	  /* A bare symbol name that is implicitly paired to an
+	     empty string.  */
+	  unread_char (c);
+	  read_name (&name);
+	  string = "";
+	}
+      else
+	{
+	  /* A "(name string)" pair.  */
+	  read_name (&name);
+	  string = read_string (false);
+	  c = read_skip_spaces ();
+	  if (c != ')')
+	    fatal_expected_char (')', c);
+	}
+      number = group->find_builtin (name.string);
+      end_ptr = add_map_value (end_ptr, number, string);
+      c = read_skip_spaces ();
+    }
+  while (c != ']');
+
+  return m;
+}
+
+/* Check newly-created code iterator ITERATOR to see whether every code has the
+   same format.  Initialize the iterator's entry in bellwether_codes.  */
+
+static void
+check_code_iterator (struct mapping *iterator)
+{
+  struct map_value *v;
+  enum rtx_code bellwether;
+
+  bellwether = (enum rtx_code) iterator->values->number;
+  for (v = iterator->values->next; v != 0; v = v->next)
+    if (strcmp (GET_RTX_FORMAT (bellwether), GET_RTX_FORMAT (v->number)) != 0)
+      fatal_with_file_and_line ("code iterator `%s' combines "
+				"different rtx formats", iterator->name);
+
+  bellwether_codes = XRESIZEVEC (enum rtx_code, bellwether_codes,
+				 iterator->index + 1);
+  bellwether_codes[iterator->index] = bellwether;
+}
+
+/* Read an rtx-related declaration from the MD file, given that it
+   starts with directive name RTX_NAME.  Return true if it expands to
+   one or more rtxes (as defined by rtx.def).  When returning true,
+   store the list of rtxes as an EXPR_LIST in *X.  */
+
+bool
+read_rtx (const char *rtx_name, rtx *x)
+{
+  static rtx queue_head;
+  struct map_value *mode_maps;
+  struct iterator_traverse_data mtd;
+
+  /* Do one-time initialization.  */
+  if (queue_head == 0)
+    {
+      initialize_iterators ();
+      queue_head = rtx_alloc (EXPR_LIST);
+    }
+
+  /* Handle various rtx-related declarations that aren't themselves
+     encoded as rtxes.  */
+  if (strcmp (rtx_name, "define_conditions") == 0)
+    {
+      read_conditions ();
+      return false;
+    }
+  if (strcmp (rtx_name, "define_mode_attr") == 0)
+    {
+      read_mapping (&modes, modes.attrs);
+      return false;
+    }
+  if (strcmp (rtx_name, "define_mode_iterator") == 0)
+    {
+      read_mapping (&modes, modes.iterators);
+      return false;
+    }
+  if (strcmp (rtx_name, "define_code_attr") == 0)
+    {
+      read_mapping (&codes, codes.attrs);
+      return false;
+    }
+  if (strcmp (rtx_name, "define_code_iterator") == 0)
+    {
+      check_code_iterator (read_mapping (&codes, codes.iterators));
+      return false;
+    }
+
+  mode_maps = 0;
+  XEXP (queue_head, 0) = read_rtx_code (rtx_name, &mode_maps);
+  XEXP (queue_head, 1) = 0;
+
+  mtd.queue = queue_head;
+  mtd.mode_maps = mode_maps;
+  mtd.unknown_mode_attr = mode_maps ? mode_maps->string : NULL;
+  htab_traverse (modes.iterators, apply_iterator_traverse, &mtd);
+  htab_traverse (codes.iterators, apply_iterator_traverse, &mtd);
+  if (mtd.unknown_mode_attr)
+    fatal_with_file_and_line ("undefined attribute '%s' used for mode",
+			      mtd.unknown_mode_attr);
+
+  *x = queue_head;
+  return true;
+}
+
+/* Subroutine of read_rtx and read_nested_rtx.  CODE_NAME is the name of
+   either an rtx code or a code iterator.  Parse the rest of the rtx and
+   return it.  MODE_MAPS is as for iterator_traverse_data.  */
+
+static rtx
+read_rtx_code (const char *code_name, struct map_value **mode_maps)
+{
+  int i;
+  RTX_CODE real_code, bellwether_code;
+  const char *format_ptr;
+  struct md_name name;
+  rtx return_rtx;
+  int c;
+  int tmp_int;
+  HOST_WIDE_INT tmp_wide;
+
+  /* Linked list structure for making RTXs: */
+  struct rtx_list
+    {
+      struct rtx_list *next;
+      rtx value;		/* Value of this node.  */
+    };
+
+  real_code = (enum rtx_code) find_iterator (&codes, code_name);
+  bellwether_code = BELLWETHER_CODE (real_code);
+
+  /* If we end up with an insn expression then we free this space below.  */
+  return_rtx = rtx_alloc (bellwether_code);
+  format_ptr = GET_RTX_FORMAT (bellwether_code);
+  PUT_CODE (return_rtx, real_code);
+
+  /* If what follows is `: mode ', read it and
+     store the mode in the rtx.  */
+
+  i = read_skip_spaces ();
+  if (i == ':')
+    {
+      unsigned int mode;
+
+      read_name (&name);
+      if (name.string[0] != '<' || name.string[strlen (name.string) - 1] != '>')
+	mode = find_iterator (&modes, name.string);
+      else
+	mode = mode_attr_index (mode_maps, name.string);
+      PUT_MODE (return_rtx, (enum machine_mode) mode);
+      if (GET_MODE (return_rtx) != mode)
+	fatal_with_file_and_line ("mode too large");
+    }
+  else
+    unread_char (i);
+
+  for (i = 0; format_ptr[i] != 0; i++)
+    switch (format_ptr[i])
+      {
+	/* 0 means a field for internal use only.
+	   Don't expect it to be present in the input.  */
+      case '0':
+	break;
+
+      case 'e':
+      case 'u':
+	XEXP (return_rtx, i) = read_nested_rtx (mode_maps);
+	break;
+
+      case 'V':
+	/* 'V' is an optional vector: if a closeparen follows,
+	   just store NULL for this element.  */
+	c = read_skip_spaces ();
+	unread_char (c);
+	if (c == ')')
+	  {
+	    XVEC (return_rtx, i) = 0;
+	    break;
+	  }
+	/* Now process the vector.  */
+
+      case 'E':
+	{
+	  /* Obstack to store scratch vector in.  */
+	  struct obstack vector_stack;
+	  int list_counter = 0;
+	  rtvec return_vec = NULL_RTVEC;
+
+	  c = read_skip_spaces ();
+	  if (c != '[')
+	    fatal_expected_char ('[', c);
+
+	  /* Add expressions to a list, while keeping a count.  */
+	  obstack_init (&vector_stack);
+	  while ((c = read_skip_spaces ()) && c != ']')
+	    {
+	      if (c == EOF)
+		fatal_expected_char (']', c);
+	      unread_char (c);
+	      list_counter++;
+	      obstack_ptr_grow (&vector_stack, read_nested_rtx (mode_maps));
+	    }
+	  if (list_counter > 0)
+	    {
+	      return_vec = rtvec_alloc (list_counter);
+	      memcpy (&return_vec->elem[0], obstack_finish (&vector_stack),
+		      list_counter * sizeof (rtx));
+	    }
+	  else if (format_ptr[i] == 'E')
+	    fatal_with_file_and_line ("vector must have at least one element");
+	  XVEC (return_rtx, i) = return_vec;
+	  obstack_free (&vector_stack, NULL);
+	  /* close bracket gotten */
+	}
+	break;
+
+      case 'S':
+      case 'T':
+      case 's':
+	{
+	  char *stringbuf;
+	  int star_if_braced;
+
+	  c = read_skip_spaces ();
+	  unread_char (c);
+	  if (c == ')')
+	    {
+	      /* 'S' fields are optional and should be NULL if no string
+		 was given.  Also allow normal 's' and 'T' strings to be
+		 omitted, treating them in the same way as empty strings.  */
+	      XSTR (return_rtx, i) = (format_ptr[i] == 'S' ? NULL : "");
+	      break;
+	    }
+
+	  /* The output template slot of a DEFINE_INSN,
+	     DEFINE_INSN_AND_SPLIT, or DEFINE_PEEPHOLE automatically
+	     gets a star inserted as its first character, if it is
+	     written with a brace block instead of a string constant.  */
+	  star_if_braced = (format_ptr[i] == 'T');
+
+	  stringbuf = read_string (star_if_braced);
+
+	  /* For insn patterns, we want to provide a default name
+	     based on the file and line, like "*foo.md:12", if the
+	     given name is blank.  These are only for define_insn and
+	     define_insn_and_split, to aid debugging.  */
+	  if (*stringbuf == '\0'
+	      && i == 0
+	      && (GET_CODE (return_rtx) == DEFINE_INSN
+		  || GET_CODE (return_rtx) == DEFINE_INSN_AND_SPLIT))
+	    {
+	      char line_name[20];
+	      const char *fn = (read_md_filename ? read_md_filename : "rtx");
+	      const char *slash;
+	      for (slash = fn; *slash; slash ++)
+		if (*slash == '/' || *slash == '\\' || *slash == ':')
+		  fn = slash + 1;
+	      obstack_1grow (&string_obstack, '*');
+	      obstack_grow (&string_obstack, fn, strlen (fn));
+	      sprintf (line_name, ":%d", read_md_lineno);
+	      obstack_grow (&string_obstack, line_name, strlen (line_name)+1);
+	      stringbuf = XOBFINISH (&string_obstack, char *);
+	    }
+
+	  if (star_if_braced)
+	    XTMPL (return_rtx, i) = stringbuf;
+	  else
+	    XSTR (return_rtx, i) = stringbuf;
+	}
+	break;
+
+      case 'w':
+	read_name (&name);
+	validate_const_int (name.string);
+#if HOST_BITS_PER_WIDE_INT == HOST_BITS_PER_INT
+	tmp_wide = atoi (name.string);
+#else
+#if HOST_BITS_PER_WIDE_INT == HOST_BITS_PER_LONG
+	tmp_wide = atol (name.string);
+#else
+	/* Prefer atoll over atoq, since the former is in the ISO C99 standard.
+	   But prefer not to use our hand-rolled function above either.  */
+#if defined(HAVE_ATOLL) || !defined(HAVE_ATOQ)
+	tmp_wide = atoll (name.string);
+#else
+	tmp_wide = atoq (name.string);
+#endif
+#endif
+#endif
+	XWINT (return_rtx, i) = tmp_wide;
+	break;
+
+      case 'i':
+      case 'n':
+	read_name (&name);
+	validate_const_int (name.string);
+	tmp_int = atoi (name.string);
+	XINT (return_rtx, i) = tmp_int;
+	break;
+
+      default:
+	gcc_unreachable ();
+      }
+
+  c = read_skip_spaces ();
+  /* Syntactic sugar for AND and IOR, allowing Lisp-like
+     arbitrary number of arguments for them.  */
+  if (c == '('
+      && (GET_CODE (return_rtx) == AND
+	  || GET_CODE (return_rtx) == IOR))
+    return read_rtx_variadic (mode_maps, return_rtx);
+
+  unread_char (c);
+  return return_rtx;
+}
+
+/* Read a nested rtx construct from the MD file and return it.
+   MODE_MAPS is as for iterator_traverse_data.  */
+
+static rtx
+read_nested_rtx (struct map_value **mode_maps)
+{
+  struct md_name name;
+  int c;
+  rtx return_rtx;
+
+  c = read_skip_spaces ();
+  if (c != '(')
+    fatal_expected_char ('(', c);
+
+  read_name (&name);
+  if (strcmp (name.string, "nil") == 0)
+    return_rtx = NULL;
+  else
+    return_rtx = read_rtx_code (name.string, mode_maps);
+
+  c = read_skip_spaces ();
+  if (c != ')')
+    fatal_expected_char (')', c);
+
+  return return_rtx;
+}
+
+/* Mutually recursive subroutine of read_rtx which reads
+   (thing x1 x2 x3 ...) and produces RTL as if
+   (thing x1 (thing x2 (thing x3 ...)))  had been written.
+   When called, FORM is (thing x1 x2), and the file position
+   is just past the leading parenthesis of x3.  Only works
+   for THINGs which are dyadic expressions, e.g. AND, IOR.  */
+static rtx
+read_rtx_variadic (struct map_value **mode_maps, rtx form)
+{
+  char c = '(';
+  rtx p = form, q;
+
+  do
+    {
+      unread_char (c);
+
+      q = rtx_alloc (GET_CODE (p));
+      PUT_MODE (q, GET_MODE (p));
+
+      XEXP (q, 0) = XEXP (p, 1);
+      XEXP (q, 1) = read_nested_rtx (mode_maps);
+
+      XEXP (p, 1) = q;
+      p = q;
+      c = read_skip_spaces ();
+    }
+  while (c == '(');
+  unread_char (c);
+  return form;
+}