Initial revision

git-svn-id: svn+ssh://gcc.gnu.org/svn/gcc/trunk@104 138bc75d-0d04-0410-961f-82ee72b054a4

1 files changed, 819 insertions, 0 deletions

diff --git a/gcc/rtl.c b/gcc/rtl.c
new file mode 100644
index 00000000000..e623f63d0db
--- /dev/null
+++ b/gcc/rtl.c
@@ -0,0 +1,819 @@
+/* Allocate and read RTL for GNU C Compiler.
+   Copyright (C) 1987-1991 Free Software Foundation, Inc.
+
+This file is part of GNU CC.
+
+GNU CC 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 2, or (at your option)
+any later version.
+
+GNU CC 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 GNU CC; see the file COPYING.  If not, write to
+the Free Software Foundation, 675 Mass Ave, Cambridge, MA 02139, USA.  */
+
+
+#include "config.h"
+#include <ctype.h>
+#include <stdio.h>
+#include "rtl.h"
+
+#include "obstack.h"
+#define	obstack_chunk_alloc	xmalloc
+#define	obstack_chunk_free	free
+extern int xmalloc ();
+extern void free ();
+
+/* Obstack used for allocating RTL objects.
+   Between functions, this is the permanent_obstack.
+   While parsing and expanding a function, this is maybepermanent_obstack
+   so we can save it if it is an inline function.
+   During optimization and output, this is function_obstack.  */
+
+extern struct obstack *rtl_obstack;
+
+extern long ftell();
+
+/* Indexed by rtx code, gives number of operands for an rtx with that code.
+   Does NOT include rtx header data (code and links).
+   This array is initialized in init_rtl.  */
+
+int rtx_length[NUM_RTX_CODE + 1];
+
+/* Indexed by rtx code, gives the name of that kind of rtx, as a C string.  */
+
+#define DEF_RTL_EXPR(ENUM, NAME, FORMAT, CLASS)   NAME ,
+
+char *rtx_name[] = {
+#include "rtl.def"		/* rtl expressions are documented here */
+};
+
+#undef DEF_RTL_EXPR
+
+/* Indexed by machine mode, gives the name of that machine mode.
+   This name does not include the letters "mode".  */
+
+#define DEF_MACHMODE(SYM, NAME, CLASS, SIZE, UNIT, WIDER)  NAME,
+
+char *mode_name[(int) MAX_MACHINE_MODE] = {
+#include "machmode.def"
+
+#ifdef EXTRA_CC_MODES
+  EXTRA_CC_NAMES
+#endif
+
+};
+
+#undef DEF_MACHMODE
+
+/* Indexed by machine mode, gives the length of the mode, in bytes.
+   GET_MODE_CLASS uses this.  */
+
+#define DEF_MACHMODE(SYM, NAME, CLASS, SIZE, UNIT, WIDER)  CLASS,
+
+enum mode_class mode_class[(int) MAX_MACHINE_MODE] = {
+#include "machmode.def"
+};
+
+#undef DEF_MACHMODE
+
+/* Indexed by machine mode, gives the length of the mode, in bytes.
+   GET_MODE_SIZE uses this.  */
+
+#define DEF_MACHMODE(SYM, NAME, CLASS, SIZE, UNIT, WIDER)  SIZE,
+
+int mode_size[(int) MAX_MACHINE_MODE] = {
+#include "machmode.def"
+};
+
+#undef DEF_MACHMODE
+
+/* Indexed by machine mode, gives the length of the mode's subunit.
+   GET_MODE_UNIT_SIZE uses this.  */
+
+#define DEF_MACHMODE(SYM, NAME, CLASS, SIZE, UNIT, WIDER)  UNIT,
+
+int mode_unit_size[(int) MAX_MACHINE_MODE] = {
+#include "machmode.def"		/* machine modes are documented here */
+};
+
+#undef DEF_MACHMODE
+
+/* Indexed by machine mode, gives next wider natural mode
+   (QI -> HI -> SI -> DI, etc.)  Widening multiply instructions
+   use this.  */
+
+#define DEF_MACHMODE(SYM, NAME, CLASS, SIZE, UNIT, WIDER)  \
+  (enum machine_mode) WIDER,
+
+enum machine_mode mode_wider_mode[(int) MAX_MACHINE_MODE] = {
+#include "machmode.def"		/* machine modes are documented here */
+};
+
+#undef DEF_MACHMODE
+
+/* Indexed by rtx code, gives a sequence of operand-types for
+   rtx's of that code.  The sequence is a C string in which
+   each charcter describes one operand.  */
+
+char *rtx_format[] = {
+  /* "*" undefined.
+         can cause a warning message
+     "0" field is unused (or used in a phase-dependent manner)
+         prints nothing
+     "i" an integer
+         prints the integer
+     "n" like "i", but prints entries from `note_insn_name'
+     "s" a pointer to a string
+         prints the string
+     "S" like "s", but optional:
+	 the containing rtx may end before this operand
+     "e" a pointer to an rtl expression
+         prints the expression
+     "E" a pointer to a vector that points to a number of rtl expressions
+         prints a list of the rtl expressions
+     "V" like "E", but optional:
+	 the containing rtx may end before this operand
+     "u" a pointer to another insn
+         prints the uid of the insn.  */
+
+#define DEF_RTL_EXPR(ENUM, NAME, FORMAT, CLASS)   FORMAT ,
+#include "rtl.def"		/* rtl expressions are defined here */
+#undef DEF_RTL_EXPR
+};
+
+/* Indexed by rtx code, gives a character representing the "class" of
+   that rtx code.  See rtl.def for documentation on the defined classes.  */
+
+char rtx_class[] = {
+#define DEF_RTL_EXPR(ENUM, NAME, FORMAT, CLASS)   CLASS, 
+#include "rtl.def"		/* rtl expressions are defined here */
+#undef DEF_RTL_EXPR
+};
+
+/* Names for kinds of NOTEs and REG_NOTEs.  */
+
+char *note_insn_name[] = { "NOTE_INSN_FUNCTION_BEG", "NOTE_INSN_DELETED",
+			   "NOTE_INSN_BLOCK_BEG", "NOTE_INSN_BLOCK_END",
+			   "NOTE_INSN_LOOP_BEG", "NOTE_INSN_LOOP_END",
+			   "NOTE_INSN_FUNCTION_END", "NOTE_INSN_SETJMP",
+			   "NOTE_INSN_LOOP_CONT", "NOTE_INSN_LOOP_VTOP" };
+
+char *reg_note_name[] = { "", "REG_DEAD", "REG_INC", "REG_EQUIV", "REG_WAS_0",
+			  "REG_EQUAL", "REG_RETVAL", "REG_LIBCALL",
+			  "REG_NONNEG", "REG_NO_CONFLICT", "REG_UNUSED",
+			  "REG_CC_SETTER", "REG_CC_USER", "REG_LABEL",
+			  "REG_DEP_ANTI", "REG_DEP_OUTPUT" };
+
+/* Allocate an rtx vector of N elements.
+   Store the length, and initialize all elements to zero.  */
+
+rtvec
+rtvec_alloc (n)
+     int n;
+{
+  rtvec rt;
+  int i;
+
+  rt = (rtvec) obstack_alloc (rtl_obstack,
+			      sizeof (struct rtvec_def)
+			      + (( n - 1) * sizeof (rtunion)));
+
+  /* clear out the vector */
+  PUT_NUM_ELEM(rt, n);
+  for (i=0; i < n; i++)
+    rt->elem[i].rtvec = NULL;	/* @@ not portable due to rtunion */
+
+  return rt;
+}
+
+/* Allocate an rtx of code CODE.  The CODE is stored in the rtx;
+   all the rest is initialized to zero.  */
+
+rtx
+rtx_alloc (code)
+  RTX_CODE code;
+{
+  rtx rt;
+  register struct obstack *ob = rtl_obstack;
+  register int nelts = GET_RTX_LENGTH (code);
+  register int length = sizeof (struct rtx_def)
+    + (nelts - 1) * sizeof (rtunion);
+
+  /* This function is called more than any other in GCC,
+     so we manipulate the obstack directly.
+
+     Even though rtx objects are word aligned, we may be sharing an obstack
+     with tree nodes, which may have to be double-word aligned.  So align
+     our length to the alignment mask in the obstack.  */
+
+  length = (length + ob->alignment_mask) & ~ ob->alignment_mask;
+
+  if (ob->chunk_limit - ob->next_free < length)
+    _obstack_newchunk (ob, length);
+  rt = (rtx)ob->object_base;
+  ob->next_free += length;
+  ob->object_base = ob->next_free;
+
+  * (int *) rt = 0;
+  PUT_CODE (rt, code);
+
+  return rt;
+}
+
+/* Create a new copy of an rtx.
+   Recursively copies the operands of the rtx,
+   except for those few rtx codes that are sharable.  */
+
+rtx
+copy_rtx (orig)
+     register rtx orig;
+{
+  register rtx copy;
+  register int i, j;
+  register RTX_CODE code;
+  register char *format_ptr;
+
+  code = GET_CODE (orig);
+
+  switch (code)
+    {
+    case REG:
+    case QUEUED:
+    case CONST_INT:
+    case CONST_DOUBLE:
+    case SYMBOL_REF:
+    case CODE_LABEL:
+    case PC:
+    case CC0:
+      return orig;
+    }
+
+  copy = rtx_alloc (code);
+  PUT_MODE (copy, GET_MODE (orig));
+  copy->in_struct = orig->in_struct;
+  copy->volatil = orig->volatil;
+  copy->unchanging = orig->unchanging;
+  copy->integrated = orig->integrated;
+  
+  format_ptr = GET_RTX_FORMAT (GET_CODE (copy));
+
+  for (i = 0; i < GET_RTX_LENGTH (GET_CODE (copy)); i++)
+    {
+      switch (*format_ptr++)
+	{
+	case 'e':
+	  XEXP (copy, i) = XEXP (orig, i);
+	  if (XEXP (orig, i) != NULL)
+	    XEXP (copy, i) = copy_rtx (XEXP (orig, i));
+	  break;
+
+	case 'E':
+	case 'V':
+	  XVEC (copy, i) = XVEC (orig, i);
+	  if (XVEC (orig, i) != NULL)
+	    {
+	      XVEC (copy, i) = rtvec_alloc (XVECLEN (orig, i));
+	      for (j = 0; j < XVECLEN (copy, i); j++)
+		XVECEXP (copy, i, j) = copy_rtx (XVECEXP (orig, i, j));
+	    }
+	  break;
+
+	default:
+	  XINT (copy, i) = XINT (orig, i);
+	  break;
+	}
+    }
+  return copy;
+}
+
+/* Similar to `copy_rtx' except that if MAY_SHARE is present, it is
+   placed in the result directly, rather than being copied.  */
+
+rtx
+copy_most_rtx (orig, may_share)
+     register rtx orig;
+     register rtx may_share;
+{
+  register rtx copy;
+  register int i, j;
+  register RTX_CODE code;
+  register char *format_ptr;
+
+  if (orig == may_share)
+    return orig;
+
+  code = GET_CODE (orig);
+
+  switch (code)
+    {
+    case REG:
+    case QUEUED:
+    case CONST_INT:
+    case CONST_DOUBLE:
+    case SYMBOL_REF:
+    case CODE_LABEL:
+    case PC:
+    case CC0:
+      return orig;
+    }
+
+  copy = rtx_alloc (code);
+  PUT_MODE (copy, GET_MODE (orig));
+  copy->in_struct = orig->in_struct;
+  copy->volatil = orig->volatil;
+  copy->unchanging = orig->unchanging;
+  copy->integrated = orig->integrated;
+  
+  format_ptr = GET_RTX_FORMAT (GET_CODE (copy));
+
+  for (i = 0; i < GET_RTX_LENGTH (GET_CODE (copy)); i++)
+    {
+      switch (*format_ptr++)
+	{
+	case 'e':
+	  XEXP (copy, i) = XEXP (orig, i);
+	  if (XEXP (orig, i) != NULL && XEXP (orig, i) != may_share)
+	    XEXP (copy, i) = copy_most_rtx (XEXP (orig, i), may_share);
+	  break;
+
+	case 'E':
+	case 'V':
+	  XVEC (copy, i) = XVEC (orig, i);
+	  if (XVEC (orig, i) != NULL)
+	    {
+	      XVEC (copy, i) = rtvec_alloc (XVECLEN (orig, i));
+	      for (j = 0; j < XVECLEN (copy, i); j++)
+		XVECEXP (copy, i, j)
+		  = copy_most_rtx (XVECEXP (orig, i, j), may_share);
+	    }
+	  break;
+
+	default:
+	  XINT (copy, i) = XINT (orig, i);
+	  break;
+	}
+    }
+  return copy;
+}
+
+/* Helper functions for instruction scheduling.  */
+
+/* Add ELEM wrapped in an INSN_LIST with reg note kind DEP_TYPE to the
+   LOG_LINKS of INSN, if not already there.  DEP_TYPE indicates the type
+   of dependence that this link represents.  */
+
+void
+add_dependence (insn, elem, dep_type)
+     rtx insn;
+     rtx elem;
+     enum reg_note dep_type;
+{
+  rtx link;
+
+  /* Don't depend an insn on itself.  */
+  if (insn == elem)
+    return;
+
+  /* If elem is part of a sequence that must be scheduled together, then
+     make the dependence point to the last insn of the sequence.  */
+  if (NEXT_INSN (elem) && SCHED_GROUP_P (NEXT_INSN (elem)))
+    {
+      while (NEXT_INSN (elem) && SCHED_GROUP_P (NEXT_INSN (elem)))
+	elem = NEXT_INSN (elem);
+      /* Again, don't depend an insn of itself.  */
+      if (insn == elem)
+	return;
+    }
+
+  /* Check that we don't already have this dependence.  */
+  for (link = LOG_LINKS (insn); link; link = XEXP (link, 1))
+    if (XEXP (link, 0) == elem)
+      {
+	/* If this is a more restrictive type of dependence than the existing
+	   one, then change the existing dependence to this type.  */
+	if (dep_type < REG_NOTE_KIND (link))
+	  PUT_REG_NOTE_KIND (link, dep_type);
+	return;
+      }
+  /* Might want to check one level of transitivity to save conses.  */
+
+  link = rtx_alloc (INSN_LIST);
+  /* Insn dependency, not data dependency.  */
+  PUT_REG_NOTE_KIND (link, dep_type);
+  XEXP (link, 0) = elem;
+  XEXP (link, 1) = LOG_LINKS (insn);
+  LOG_LINKS (insn) = link;
+}
+
+/* Remove ELEM wrapped in an INSN_LIST from the LOG_LINKS
+   of INSN.  Abort if not found.  */
+void
+remove_dependence (insn, elem)
+     rtx insn;
+     rtx elem;
+{
+  rtx prev, link;
+  int found = 0;
+
+  for (prev = 0, link = LOG_LINKS (insn); link;
+       prev = link, link = XEXP (link, 1))
+    {
+      if (XEXP (link, 0) == elem)
+	{
+	  if (prev)
+	    XEXP (prev, 1) = XEXP (link, 1);
+	  else
+	    LOG_LINKS (insn) = XEXP (link, 1);
+	  found = 1;
+	}
+    }
+
+  if (! found)
+    abort ();
+  return;
+}
+
+/* Subroutines of read_rtx.  */
+
+/* Dump code after printing a message.  Used when read_rtx finds
+   invalid data.  */
+
+static void
+dump_and_abort (expected_c, actual_c, infile)
+     int expected_c, actual_c;
+     FILE *infile;
+{
+  int c, i;
+
+  if (expected_c >= 0)
+    fprintf (stderr,
+	     "Expected character %c.  Found character %c.",
+	     expected_c, actual_c);
+  fprintf (stderr, "  At file position: %ld\n", ftell (infile));
+  fprintf (stderr, "Following characters are:\n\t");
+  for (i = 0; i < 200; i++)
+    {
+      c = getc (infile);
+      if (EOF == c) break;
+      putc (c, stderr);
+    }
+  fprintf (stderr, "Aborting.\n");
+  abort ();
+}
+
+/* Read chars from INFILE until a non-whitespace char
+   and return that.  Comments, both Lisp style and C style,
+   are treated as whitespace.
+   Tools such as genflags use this function.  */
+
+int
+read_skip_spaces (infile)
+     FILE *infile;
+{
+  register int c;
+  while (c = getc (infile))
+    {
+      if (c == ' ' || c == '\n' || c == '\t' || c == '\f')
+	;
+      else if (c == ';')
+	{
+	  while ((c = getc (infile)) && c != '\n') ;
+	}
+      else if (c == '/')
+	{
+	  register int prevc;
+	  c = getc (infile);
+	  if (c != '*')
+	    dump_and_abort ('*', c, infile);
+	  
+	  prevc = 0;
+	  while (c = getc (infile))
+	    {
+	      if (prevc == '*' && c == '/')
+		break;
+	      prevc = c;
+	    }
+	}
+      else break;
+    }
+  return c;
+}
+
+/* Read an rtx code name into the buffer STR[].
+   It is terminated by any of the punctuation chars of rtx printed syntax.  */
+
+static void
+read_name (str, infile)
+     char *str;
+     FILE *infile;
+{
+  register char *p;
+  register int c;
+
+  c = read_skip_spaces(infile);
+
+  p = str;
+  while (1)
+    {
+      if (c == ' ' || c == '\n' || c == '\t' || c == '\f')
+	break;
+      if (c == ':' || c == ')' || c == ']' || c == '"' || c == '/'
+	  || c == '(' || c == '[')
+	{
+	  ungetc (c, infile);
+	  break;
+	}
+      *p++ = c;
+      c = getc (infile);
+    }
+  if (p == str)
+    {
+      fprintf (stderr, "missing name or number");
+      dump_and_abort (-1, -1, infile);
+    }
+
+  *p = 0;
+}
+
+/* Read an rtx in printed representation from INFILE
+   and return an actual rtx in core constructed accordingly.
+   read_rtx is not used in the compiler proper, but rather in
+   the utilities gen*.c that construct C code from machine descriptions.  */
+
+rtx
+read_rtx (infile)
+     FILE *infile;
+{
+  register int i, j, list_counter;
+  RTX_CODE tmp_code;
+  register char *format_ptr;
+  /* tmp_char is a buffer used for reading decimal integers
+     and names of rtx types and machine modes.
+     Therefore, 256 must be enough.  */
+  char tmp_char[256];
+  rtx return_rtx;
+  register int c;
+  int tmp_int;
+
+  /* Linked list structure for making RTXs: */
+  struct rtx_list
+    {
+      struct rtx_list *next;
+      rtx value;		/* Value of this node...		*/
+    };
+
+  c = read_skip_spaces (infile); /* Should be open paren.  */
+  if (c != '(')
+    dump_and_abort ('(', c, infile);
+
+  read_name (tmp_char, infile);
+
+  tmp_code = UNKNOWN;
+
+  for (i=0; i < NUM_RTX_CODE; i++) /* @@ might speed this search up */
+    {
+      if (!(strcmp (tmp_char, GET_RTX_NAME (i))))
+	{
+	  tmp_code = (RTX_CODE) i;	/* get value for name */
+	  break;
+	}
+    }
+  if (tmp_code == UNKNOWN)
+    {
+      fprintf (stderr,
+	       "Unknown rtx read in rtl.read_rtx(). Code name was %s .",
+	       tmp_char);
+    }
+  /* (NIL) stands for an expression that isn't there.  */
+  if (tmp_code == NIL)
+    {
+      /* Discard the closeparen.  */
+      while ((c = getc (infile)) && c != ')');
+      return 0;
+    }
+
+  return_rtx = rtx_alloc (tmp_code); /* if we end up with an insn expression
+				       then we free this space below.  */
+  format_ptr = GET_RTX_FORMAT (GET_CODE (return_rtx));
+
+  /* If what follows is `: mode ', read it and
+     store the mode in the rtx.  */
+
+  i = read_skip_spaces (infile);
+  if (i == ':')
+    {
+      register int k;
+      read_name (tmp_char, infile);
+      for (k = 0; k < NUM_MACHINE_MODES; k++)
+	if (!strcmp (GET_MODE_NAME (k), tmp_char))
+	  break;
+
+      PUT_MODE (return_rtx, (enum machine_mode) k );
+    }
+  else
+    ungetc (i, infile);
+
+  for (i = 0; i < GET_RTX_LENGTH (GET_CODE (return_rtx)); i++)
+    switch (*format_ptr++)
+      {
+	/* 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_rtx (infile);
+	break;
+
+      case 'V':
+	/* 'V' is an optional vector: if a closeparen follows,
+	   just store NULL for this element.  */
+	c = read_skip_spaces (infile);
+	ungetc (c, infile);
+	if (c == ')')
+	  {
+	    XVEC (return_rtx, i) = 0;
+	    break;
+ 	  }
+	/* Now process the vector.  */
+  
+      case 'E':
+	{
+	  register struct rtx_list *next_rtx, *rtx_list_link;
+	  struct rtx_list *list_rtx;
+
+	  c = read_skip_spaces (infile);
+	  if (c != '[')
+	    dump_and_abort ('[', c, infile);
+
+	  /* add expressions to a list, while keeping a count */
+	  next_rtx = NULL;
+	  list_counter = 0;
+	  while ((c = read_skip_spaces (infile)) && c != ']')
+	    {
+	      ungetc (c, infile);
+	      list_counter++;
+	      rtx_list_link = (struct rtx_list *)
+		alloca (sizeof (struct rtx_list));
+	      rtx_list_link->value = read_rtx (infile);
+	      if (next_rtx == 0)
+		list_rtx = rtx_list_link;
+	      else
+		next_rtx->next = rtx_list_link;
+	      next_rtx = rtx_list_link;
+	      rtx_list_link->next = 0;
+	    }
+	  /* get vector length and allocate it */
+	  XVEC (return_rtx, i) = (list_counter
+				  ? rtvec_alloc (list_counter)
+				  : (struct rtvec_def *) NULL);
+	  if (list_counter > 0)
+	    {
+	      next_rtx = list_rtx;
+	      for (j = 0; j < list_counter; j++,
+		   next_rtx = next_rtx->next)
+		XVECEXP (return_rtx, i, j) = next_rtx->value;
+	    }
+	  /* close bracket gotten */
+	}
+	break;
+
+      case 'S':
+	/* 'S' is an optional string: if a closeparen follows,
+	   just store NULL for this element.  */
+	c = read_skip_spaces (infile);
+	ungetc (c, infile);
+	if (c == ')')
+	  {
+	    XSTR (return_rtx, i) = 0;
+	    break;
+	  }
+
+      case 's':
+	{
+	  int saw_paren = 0;
+	  register char *stringbuf;
+	  int stringbufsize;
+
+	  c = read_skip_spaces (infile);
+	  if (c == '(')
+	    {
+	      saw_paren = 1;
+	      c = read_skip_spaces (infile);
+	    }
+	  if (c != '"')
+	    dump_and_abort ('"', c, infile);
+	  j = 0;
+	  stringbufsize = 10;
+	  stringbuf = (char *) xmalloc (stringbufsize + 1);
+
+	  while (1)
+	    {
+	      if (j >= stringbufsize - 4)
+		{
+		  stringbufsize *= 2;
+		  stringbuf = (char *) xrealloc (stringbuf, stringbufsize + 1);
+		}
+	      stringbuf[j] = getc (infile); /* Read the string  */
+	      if (stringbuf[j] == '\\')
+		{
+		  stringbuf[j] = getc (infile);	/* Read the string  */
+		  /* \; makes stuff for a C string constant containing
+		     newline and tab.  */
+		  if (stringbuf[j] == ';')
+		    {
+		      strcpy (&stringbuf[j], "\\n\\t");
+		      j += 3;
+		    }
+		}
+	      else if (stringbuf[j] == '"')
+		break;
+	      j++;
+	    }
+
+	  stringbuf[j] = 0;	/* NUL terminate the string  */
+	  stringbuf = (char *) xrealloc (stringbuf, j + 1);
+
+	  if (saw_paren)
+	    {
+	      c = read_skip_spaces (infile);
+	      if (c != ')')
+		dump_and_abort (')', c, infile);
+	    }
+	  XSTR (return_rtx, i) = stringbuf;
+	}
+	break;
+
+      case 'i':
+      case 'n':
+	read_name (tmp_char, infile);
+	tmp_int = atoi (tmp_char);
+	XINT (return_rtx, i) = tmp_int;
+	break;
+
+      default:
+	fprintf (stderr,
+		 "switch format wrong in rtl.read_rtx(). format was: %c.\n",
+		 format_ptr[-1]);
+	fprintf (stderr, "\tfile position: %ld\n", ftell (infile));
+	abort ();
+      }
+
+  c = read_skip_spaces (infile);
+  if (c != ')')
+    dump_and_abort (')', c, infile);
+
+  return return_rtx;
+}
+
+/* This is called once per compilation, before any rtx's are constructed.
+   It initializes the vector `rtx_length' and the extra CC modes, if any.  */
+
+void
+init_rtl ()
+{
+  int i;
+
+  for (i = 0; i < NUM_RTX_CODE; i++)
+    rtx_length[i] = strlen (rtx_format[i]);
+
+  /* Make CONST_DOUBLE bigger, if real values are bigger than
+     it normally expects to have room for.
+     Note that REAL_VALUE_TYPE is not defined by default,
+     since tree.h is not included.  But the default dfn as `double'
+     would do no harm.  */
+#ifdef REAL_VALUE_TYPE
+  i = sizeof (REAL_VALUE_TYPE) / sizeof (rtunion) + 2;
+  if (rtx_length[(int) CONST_DOUBLE] < i)
+    {
+      char *s = (char *) xmalloc (i + 1);
+      rtx_length[(int) CONST_DOUBLE] = i;
+      rtx_format[(int) CONST_DOUBLE] = s;
+      *s++ = 'e';
+      *s++ = '0';
+      /* Set the GET_RTX_FORMAT of CONST_DOUBLE to a string
+	 of as many `i's as we now have elements.  */
+      for (i = 0; i < rtx_length[(int) CONST_DOUBLE]; i++)
+	*s++ = 'i';
+      *s++ = 0;
+    }
+#endif
+
+#ifdef EXTRA_CC_MODES
+  for (i = (int) CCmode + 1; i < (int) MAX_MACHINE_MODE; i++)
+    {
+      mode_class[i] = MODE_CC;
+      mode_size[i] = mode_size[(int) CCmode];
+      mode_unit_size[i] = mode_unit_size[(int) CCmode];
+      mode_wider_mode[i - 1] = (enum machine_mode) i;
+      mode_wider_mode[i] = VOIDmode;
+    }
+#endif
+}