configure.ac: GCC_NO_EXECUTABLES was supposed to be commented in the patch from 3...

[official-gcc.git] / gcc / builtins.c

/* Expand builtin functions.
   Copyright (C) 1988, 1992, 1993, 1994, 1995, 1996, 1997, 1998, 1999,
   2000, 2001, 2002, 2003 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 2, 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 COPYING.  If not, write to the Free
Software Foundation, 59 Temple Place - Suite 330, Boston, MA
02111-1307, USA.  */

#include "config.h"
#include "system.h"
#include "coretypes.h"
#include "tm.h"
#include "machmode.h"
#include "real.h"
#include "rtl.h"
#include "tree.h"
#include "flags.h"
#include "regs.h"
#include "hard-reg-set.h"
#include "except.h"
#include "function.h"
#include "insn-config.h"
#include "expr.h"
#include "optabs.h"
#include "libfuncs.h"
#include "recog.h"
#include "output.h"
#include "typeclass.h"
#include "toplev.h"
#include "predict.h"
#include "tm_p.h"
#include "target.h"
#include "langhooks.h"

#define CALLED_AS_BUILT_IN(NODE) \
   (!strncmp (IDENTIFIER_POINTER (DECL_NAME (NODE)), "__builtin_", 10))

/* Register mappings for target machines without register windows.  */
#ifndef INCOMING_REGNO
#define INCOMING_REGNO(OUT) (OUT)
#endif
#ifndef OUTGOING_REGNO
#define OUTGOING_REGNO(IN) (IN)
#endif

#ifndef PAD_VARARGS_DOWN
#define PAD_VARARGS_DOWN BYTES_BIG_ENDIAN
#endif

/* Define the names of the builtin function types and codes.  */
const char *const built_in_class_names[4]
  = {"NOT_BUILT_IN", "BUILT_IN_FRONTEND", "BUILT_IN_MD", "BUILT_IN_NORMAL"};

#define DEF_BUILTIN(X, N, C, T, LT, B, F, NA, AT, IM) #X,
const char *const built_in_names[(int) END_BUILTINS] =
{
#include "builtins.def"
};
#undef DEF_BUILTIN

/* Setup an array of _DECL trees, make sure each element is
   initialized to NULL_TREE.  */
tree built_in_decls[(int) END_BUILTINS];
/* Declarations used when constructing the builtin implicitly in the compiler.
   It may be NULL_TREE when this is invalid (for instance runtime is not
   required to implement the function call in all cases.  */
tree implicit_built_in_decls[(int) END_BUILTINS];

/* Trigonometric and mathematical constants used in builtin folding.  */
static bool builtin_dconsts_init = 0;
static REAL_VALUE_TYPE dconstpi;
static REAL_VALUE_TYPE dconste;

static int get_pointer_alignment (tree, unsigned int);
static tree c_strlen (tree, int);
static const char *c_getstr (tree);
static rtx c_readstr (const char *, enum machine_mode);
static int target_char_cast (tree, char *);
static rtx get_memory_rtx (tree);
static tree build_string_literal (int, const char *);
static int apply_args_size (void);
static int apply_result_size (void);
#if defined (HAVE_untyped_call) || defined (HAVE_untyped_return)
static rtx result_vector (int, rtx);
#endif
static rtx expand_builtin_setjmp (tree, rtx);
static void expand_builtin_prefetch (tree);
static rtx expand_builtin_apply_args (void);
static rtx expand_builtin_apply_args_1 (void);
static rtx expand_builtin_apply (rtx, rtx, rtx);
static void expand_builtin_return (rtx);
static enum type_class type_to_class (tree);
static rtx expand_builtin_classify_type (tree);
static void expand_errno_check (tree, rtx);
static rtx expand_builtin_mathfn (tree, rtx, rtx);
static rtx expand_builtin_mathfn_2 (tree, rtx, rtx);
static rtx expand_builtin_constant_p (tree, enum machine_mode);
static rtx expand_builtin_args_info (tree);
static rtx expand_builtin_next_arg (tree);
static rtx expand_builtin_va_start (tree);
static rtx expand_builtin_va_end (tree);
static rtx expand_builtin_va_copy (tree);
static rtx expand_builtin_memcmp (tree, tree, rtx, enum machine_mode);
static rtx expand_builtin_strcmp (tree, rtx, enum machine_mode);
static rtx expand_builtin_strncmp (tree, rtx, enum machine_mode);
static rtx builtin_memcpy_read_str (void *, HOST_WIDE_INT, enum machine_mode);
static rtx expand_builtin_strcat (tree, rtx, enum machine_mode);
static rtx expand_builtin_strncat (tree, rtx, enum machine_mode);
static rtx expand_builtin_strspn (tree, rtx, enum machine_mode);
static rtx expand_builtin_strcspn (tree, rtx, enum machine_mode);
static rtx expand_builtin_memcpy (tree, rtx, enum machine_mode);
static rtx expand_builtin_mempcpy (tree, rtx, enum machine_mode, int);
static rtx expand_builtin_memmove (tree, rtx, enum machine_mode);
static rtx expand_builtin_bcopy (tree);
static rtx expand_builtin_strcpy (tree, rtx, enum machine_mode);
static rtx expand_builtin_stpcpy (tree, rtx, enum machine_mode);
static rtx builtin_strncpy_read_str (void *, HOST_WIDE_INT, enum machine_mode);
static rtx expand_builtin_strncpy (tree, rtx, enum machine_mode);
static rtx builtin_memset_read_str (void *, HOST_WIDE_INT, enum machine_mode);
static rtx builtin_memset_gen_str (void *, HOST_WIDE_INT, enum machine_mode);
static rtx expand_builtin_memset (tree, rtx, enum machine_mode);
static rtx expand_builtin_bzero (tree);
static rtx expand_builtin_strlen (tree, rtx, enum machine_mode);
static rtx expand_builtin_strstr (tree, rtx, enum machine_mode);
static rtx expand_builtin_strpbrk (tree, rtx, enum machine_mode);
static rtx expand_builtin_strchr (tree, rtx, enum machine_mode);
static rtx expand_builtin_strrchr (tree, rtx, enum machine_mode);
static rtx expand_builtin_alloca (tree, rtx);
static rtx expand_builtin_unop (enum machine_mode, tree, rtx, rtx, optab);
static rtx expand_builtin_frame_address (tree, tree);
static rtx expand_builtin_fputs (tree, rtx, bool);
static rtx expand_builtin_printf (tree, rtx, enum machine_mode, bool);
static rtx expand_builtin_fprintf (tree, rtx, enum machine_mode, bool);
static rtx expand_builtin_sprintf (tree, rtx, enum machine_mode);
static tree stabilize_va_list (tree, int);
static rtx expand_builtin_expect (tree, rtx);
static tree fold_builtin_constant_p (tree);
static tree fold_builtin_classify_type (tree);
static tree fold_builtin_inf (tree, int);
static tree fold_builtin_nan (tree, tree, int);
static int validate_arglist (tree, ...);
static bool integer_valued_real_p (tree);
static tree fold_trunc_transparent_mathfn (tree);
static bool readonly_data_expr (tree);
static rtx expand_builtin_fabs (tree, rtx, rtx);
static rtx expand_builtin_cabs (tree, rtx);
static void init_builtin_dconsts (void);
static tree fold_builtin_cabs (tree, tree, tree);
static tree fold_builtin_trunc (tree);
static tree fold_builtin_floor (tree);
static tree fold_builtin_ceil (tree);

/* Initialize mathematical constants for constant folding builtins.
   These constants need to be given to at least 160 bits precision.  */

static void
init_builtin_dconsts (void)
{
  real_from_string (&dconstpi,
    "3.1415926535897932384626433832795028841971693993751058209749445923078");
  real_from_string (&dconste,
    "2.7182818284590452353602874713526624977572470936999595749669676277241");

  builtin_dconsts_init = true;
}

/* Return the alignment in bits of EXP, a pointer valued expression.
   But don't return more than MAX_ALIGN no matter what.
   The alignment returned is, by default, the alignment of the thing that
   EXP points to.  If it is not a POINTER_TYPE, 0 is returned.

   Otherwise, look at the expression to see if we can do better, i.e., if the
   expression is actually pointing at an object whose alignment is tighter.  */

static int
get_pointer_alignment (tree exp, unsigned int max_align)
{
  unsigned int align, inner;

  if (TREE_CODE (TREE_TYPE (exp)) != POINTER_TYPE)
    return 0;

  align = TYPE_ALIGN (TREE_TYPE (TREE_TYPE (exp)));
  align = MIN (align, max_align);

  while (1)
    {
      switch (TREE_CODE (exp))
        {
        case NOP_EXPR:
        case CONVERT_EXPR:
        case NON_LVALUE_EXPR:
          exp = TREE_OPERAND (exp, 0);
          if (TREE_CODE (TREE_TYPE (exp)) != POINTER_TYPE)
            return align;

          inner = TYPE_ALIGN (TREE_TYPE (TREE_TYPE (exp)));
          align = MIN (inner, max_align);
          break;

        case PLUS_EXPR:
          /* If sum of pointer + int, restrict our maximum alignment to that
             imposed by the integer.  If not, we can't do any better than
             ALIGN.  */
          if (! host_integerp (TREE_OPERAND (exp, 1), 1))
            return align;

          while (((tree_low_cst (TREE_OPERAND (exp, 1), 1))
                  & (max_align / BITS_PER_UNIT - 1))
                 != 0)
            max_align >>= 1;

          exp = TREE_OPERAND (exp, 0);
          break;

        case ADDR_EXPR:
          /* See what we are pointing at and look at its alignment.  */
          exp = TREE_OPERAND (exp, 0);
          if (TREE_CODE (exp) == FUNCTION_DECL)
            align = FUNCTION_BOUNDARY;
          else if (DECL_P (exp))
            align = DECL_ALIGN (exp);
#ifdef CONSTANT_ALIGNMENT
          else if (TREE_CODE_CLASS (TREE_CODE (exp)) == 'c')
            align = CONSTANT_ALIGNMENT (exp, align);
#endif
          return MIN (align, max_align);

        default:
          return align;
        }
    }
}

/* Compute the length of a C string.  TREE_STRING_LENGTH is not the right
   way, because it could contain a zero byte in the middle.
   TREE_STRING_LENGTH is the size of the character array, not the string.

   ONLY_VALUE should be nonzero if the result is not going to be emitted
   into the instruction stream and zero if it is going to be expanded.
   E.g. with i++ ? "foo" : "bar", if ONLY_VALUE is nonzero, constant 3
   is returned, otherwise NULL, since
   len = c_strlen (src, 1); if (len) expand_expr (len, ...); would not
   evaluate the side-effects.

   The value returned is of type `ssizetype'.

   Unfortunately, string_constant can't access the values of const char
   arrays with initializers, so neither can we do so here.  */

static tree
c_strlen (tree src, int only_value)
{
  tree offset_node;
  HOST_WIDE_INT offset;
  int max;
  const char *ptr;

  STRIP_NOPS (src);
  if (TREE_CODE (src) == COND_EXPR
      && (only_value || !TREE_SIDE_EFFECTS (TREE_OPERAND (src, 0))))
    {
      tree len1, len2;

      len1 = c_strlen (TREE_OPERAND (src, 1), only_value);
      len2 = c_strlen (TREE_OPERAND (src, 2), only_value);
      if (tree_int_cst_equal (len1, len2))      
        return len1;
    }

  if (TREE_CODE (src) == COMPOUND_EXPR
      && (only_value || !TREE_SIDE_EFFECTS (TREE_OPERAND (src, 0))))
    return c_strlen (TREE_OPERAND (src, 1), only_value);

  src = string_constant (src, &offset_node);
  if (src == 0)
    return 0;

  max = TREE_STRING_LENGTH (src) - 1;
  ptr = TREE_STRING_POINTER (src);

  if (offset_node && TREE_CODE (offset_node) != INTEGER_CST)
    {
      /* If the string has an internal zero byte (e.g., "foo\0bar"), we can't
         compute the offset to the following null if we don't know where to
         start searching for it.  */
      int i;

      for (i = 0; i < max; i++)
        if (ptr[i] == 0)
          return 0;

      /* We don't know the starting offset, but we do know that the string
         has no internal zero bytes.  We can assume that the offset falls
         within the bounds of the string; otherwise, the programmer deserves
         what he gets.  Subtract the offset from the length of the string,
         and return that.  This would perhaps not be valid if we were dealing
         with named arrays in addition to literal string constants.  */

      return size_diffop (size_int (max), offset_node);
    }

  /* We have a known offset into the string.  Start searching there for
     a null character if we can represent it as a single HOST_WIDE_INT.  */
  if (offset_node == 0)
    offset = 0;
  else if (! host_integerp (offset_node, 0))
    offset = -1;
  else
    offset = tree_low_cst (offset_node, 0);

  /* If the offset is known to be out of bounds, warn, and call strlen at
     runtime.  */
  if (offset < 0 || offset > max)
    {
      warning ("offset outside bounds of constant string");
      return 0;
    }

  /* Use strlen to search for the first zero byte.  Since any strings
     constructed with build_string will have nulls appended, we win even
     if we get handed something like (char[4])"abcd".

     Since OFFSET is our starting index into the string, no further
     calculation is needed.  */
  return ssize_int (strlen (ptr + offset));
}

/* Return a char pointer for a C string if it is a string constant
   or sum of string constant and integer constant.  */

static const char *
c_getstr (tree src)
{
  tree offset_node;

  src = string_constant (src, &offset_node);
  if (src == 0)
    return 0;

  if (offset_node == 0)
    return TREE_STRING_POINTER (src);
  else if (!host_integerp (offset_node, 1)
           || compare_tree_int (offset_node, TREE_STRING_LENGTH (src) - 1) > 0)
    return 0;

  return TREE_STRING_POINTER (src) + tree_low_cst (offset_node, 1);
}

/* Return a CONST_INT or CONST_DOUBLE corresponding to target reading
   GET_MODE_BITSIZE (MODE) bits from string constant STR.  */

static rtx
c_readstr (const char *str, enum machine_mode mode)
{
  HOST_WIDE_INT c[2];
  HOST_WIDE_INT ch;
  unsigned int i, j;

  if (GET_MODE_CLASS (mode) != MODE_INT)
    abort ();
  c[0] = 0;
  c[1] = 0;
  ch = 1;
  for (i = 0; i < GET_MODE_SIZE (mode); i++)
    {
      j = i;
      if (WORDS_BIG_ENDIAN)
        j = GET_MODE_SIZE (mode) - i - 1;
      if (BYTES_BIG_ENDIAN != WORDS_BIG_ENDIAN
          && GET_MODE_SIZE (mode) > UNITS_PER_WORD)
        j = j + UNITS_PER_WORD - 2 * (j % UNITS_PER_WORD) - 1;
      j *= BITS_PER_UNIT;
      if (j > 2 * HOST_BITS_PER_WIDE_INT)
        abort ();
      if (ch)
        ch = (unsigned char) str[i];
      c[j / HOST_BITS_PER_WIDE_INT] |= ch << (j % HOST_BITS_PER_WIDE_INT);
    }
  return immed_double_const (c[0], c[1], mode);
}

/* Cast a target constant CST to target CHAR and if that value fits into
   host char type, return zero and put that value into variable pointed by
   P.  */

static int
target_char_cast (tree cst, char *p)
{
  unsigned HOST_WIDE_INT val, hostval;

  if (!host_integerp (cst, 1)
      || CHAR_TYPE_SIZE > HOST_BITS_PER_WIDE_INT)
    return 1;

  val = tree_low_cst (cst, 1);
  if (CHAR_TYPE_SIZE < HOST_BITS_PER_WIDE_INT)
    val &= (((unsigned HOST_WIDE_INT) 1) << CHAR_TYPE_SIZE) - 1;

  hostval = val;
  if (HOST_BITS_PER_CHAR < HOST_BITS_PER_WIDE_INT)
    hostval &= (((unsigned HOST_WIDE_INT) 1) << HOST_BITS_PER_CHAR) - 1;

  if (val != hostval)
    return 1;

  *p = hostval;
  return 0;
}

/* Given TEM, a pointer to a stack frame, follow the dynamic chain COUNT
   times to get the address of either a higher stack frame, or a return
   address located within it (depending on FNDECL_CODE).  */

rtx
expand_builtin_return_addr (enum built_in_function fndecl_code, int count,
                            rtx tem)
{
  int i;

  /* Some machines need special handling before we can access
     arbitrary frames.  For example, on the sparc, we must first flush
     all register windows to the stack.  */
#ifdef SETUP_FRAME_ADDRESSES
  if (count > 0)
    SETUP_FRAME_ADDRESSES ();
#endif

  /* On the sparc, the return address is not in the frame, it is in a
     register.  There is no way to access it off of the current frame
     pointer, but it can be accessed off the previous frame pointer by
     reading the value from the register window save area.  */
#ifdef RETURN_ADDR_IN_PREVIOUS_FRAME
  if (fndecl_code == BUILT_IN_RETURN_ADDRESS)
    count--;
#endif

  /* Scan back COUNT frames to the specified frame.  */
  for (i = 0; i < count; i++)
    {
      /* Assume the dynamic chain pointer is in the word that the
         frame address points to, unless otherwise specified.  */
#ifdef DYNAMIC_CHAIN_ADDRESS
      tem = DYNAMIC_CHAIN_ADDRESS (tem);
#endif
      tem = memory_address (Pmode, tem);
      tem = gen_rtx_MEM (Pmode, tem);
      set_mem_alias_set (tem, get_frame_alias_set ());
      tem = copy_to_reg (tem);
    }

  /* For __builtin_frame_address, return what we've got.  */
  if (fndecl_code == BUILT_IN_FRAME_ADDRESS)
    return tem;

  /* For __builtin_return_address, Get the return address from that
     frame.  */
#ifdef RETURN_ADDR_RTX
  tem = RETURN_ADDR_RTX (count, tem);
#else
  tem = memory_address (Pmode,
                        plus_constant (tem, GET_MODE_SIZE (Pmode)));
  tem = gen_rtx_MEM (Pmode, tem);
  set_mem_alias_set (tem, get_frame_alias_set ());
#endif
  return tem;
}

/* Alias set used for setjmp buffer.  */
static HOST_WIDE_INT setjmp_alias_set = -1;

/* Construct the leading half of a __builtin_setjmp call.  Control will
   return to RECEIVER_LABEL.  This is used directly by sjlj exception
   handling code.  */

void
expand_builtin_setjmp_setup (rtx buf_addr, rtx receiver_label)
{
  enum machine_mode sa_mode = STACK_SAVEAREA_MODE (SAVE_NONLOCAL);
  rtx stack_save;
  rtx mem;

  if (setjmp_alias_set == -1)
    setjmp_alias_set = new_alias_set ();

#ifdef POINTERS_EXTEND_UNSIGNED
  if (GET_MODE (buf_addr) != Pmode)
    buf_addr = convert_memory_address (Pmode, buf_addr);
#endif

  buf_addr = force_reg (Pmode, force_operand (buf_addr, NULL_RTX));

  emit_queue ();

  /* We store the frame pointer and the address of receiver_label in
     the buffer and use the rest of it for the stack save area, which
     is machine-dependent.  */

#ifndef BUILTIN_SETJMP_FRAME_VALUE
#define BUILTIN_SETJMP_FRAME_VALUE virtual_stack_vars_rtx
#endif

  mem = gen_rtx_MEM (Pmode, buf_addr);
  set_mem_alias_set (mem, setjmp_alias_set);
  emit_move_insn (mem, BUILTIN_SETJMP_FRAME_VALUE);

  mem = gen_rtx_MEM (Pmode, plus_constant (buf_addr, GET_MODE_SIZE (Pmode))),
  set_mem_alias_set (mem, setjmp_alias_set);

  emit_move_insn (validize_mem (mem),
                  force_reg (Pmode, gen_rtx_LABEL_REF (Pmode, receiver_label)));

  stack_save = gen_rtx_MEM (sa_mode,
                            plus_constant (buf_addr,
                                           2 * GET_MODE_SIZE (Pmode)));
  set_mem_alias_set (stack_save, setjmp_alias_set);
  emit_stack_save (SAVE_NONLOCAL, &stack_save, NULL_RTX);

  /* If there is further processing to do, do it.  */
#ifdef HAVE_builtin_setjmp_setup
  if (HAVE_builtin_setjmp_setup)
    emit_insn (gen_builtin_setjmp_setup (buf_addr));
#endif

  /* Tell optimize_save_area_alloca that extra work is going to
     need to go on during alloca.  */
  current_function_calls_setjmp = 1;

  /* Set this so all the registers get saved in our frame; we need to be
     able to copy the saved values for any registers from frames we unwind.  */
  current_function_has_nonlocal_label = 1;
}

/* Construct the trailing part of a __builtin_setjmp call.
   This is used directly by sjlj exception handling code.  */

void
expand_builtin_setjmp_receiver (rtx receiver_label ATTRIBUTE_UNUSED)
{
  /* Clobber the FP when we get here, so we have to make sure it's
     marked as used by this function.  */
  emit_insn (gen_rtx_USE (VOIDmode, hard_frame_pointer_rtx));

  /* Mark the static chain as clobbered here so life information
     doesn't get messed up for it.  */
  emit_insn (gen_rtx_CLOBBER (VOIDmode, static_chain_rtx));

  /* Now put in the code to restore the frame pointer, and argument
     pointer, if needed.  The code below is from expand_end_bindings
     in stmt.c; see detailed documentation there.  */
#ifdef HAVE_nonlocal_goto
  if (! HAVE_nonlocal_goto)
#endif
    emit_move_insn (virtual_stack_vars_rtx, hard_frame_pointer_rtx);

#if ARG_POINTER_REGNUM != HARD_FRAME_POINTER_REGNUM
  if (fixed_regs[ARG_POINTER_REGNUM])
    {
#ifdef ELIMINABLE_REGS
      size_t i;
      static const struct elims {const int from, to;} elim_regs[] = ELIMINABLE_REGS;

      for (i = 0; i < ARRAY_SIZE (elim_regs); i++)
        if (elim_regs[i].from == ARG_POINTER_REGNUM
            && elim_regs[i].to == HARD_FRAME_POINTER_REGNUM)
          break;

      if (i == ARRAY_SIZE (elim_regs))
#endif
        {
          /* Now restore our arg pointer from the address at which it
             was saved in our stack frame.  */
          emit_move_insn (virtual_incoming_args_rtx,
                          copy_to_reg (get_arg_pointer_save_area (cfun)));
        }
    }
#endif

#ifdef HAVE_builtin_setjmp_receiver
  if (HAVE_builtin_setjmp_receiver)
    emit_insn (gen_builtin_setjmp_receiver (receiver_label));
  else
#endif
#ifdef HAVE_nonlocal_goto_receiver
    if (HAVE_nonlocal_goto_receiver)
      emit_insn (gen_nonlocal_goto_receiver ());
    else
#endif
      { /* Nothing */ }

  /* @@@ This is a kludge.  Not all machine descriptions define a blockage
     insn, but we must not allow the code we just generated to be reordered
     by scheduling.  Specifically, the update of the frame pointer must
     happen immediately, not later.  So emit an ASM_INPUT to act as blockage
     insn.  */
  emit_insn (gen_rtx_ASM_INPUT (VOIDmode, ""));
}

/* __builtin_setjmp is passed a pointer to an array of five words (not
   all will be used on all machines).  It operates similarly to the C
   library function of the same name, but is more efficient.  Much of
   the code below (and for longjmp) is copied from the handling of
   non-local gotos.

   NOTE: This is intended for use by GNAT and the exception handling
   scheme in the compiler and will only work in the method used by
   them.  */

static rtx
expand_builtin_setjmp (tree arglist, rtx target)
{
  rtx buf_addr, next_lab, cont_lab;

  if (!validate_arglist (arglist, POINTER_TYPE, VOID_TYPE))
    return NULL_RTX;

  if (target == 0 || GET_CODE (target) != REG
      || REGNO (target) < FIRST_PSEUDO_REGISTER)
    target = gen_reg_rtx (TYPE_MODE (integer_type_node));

  buf_addr = expand_expr (TREE_VALUE (arglist), NULL_RTX, VOIDmode, 0);

  next_lab = gen_label_rtx ();
  cont_lab = gen_label_rtx ();

  expand_builtin_setjmp_setup (buf_addr, next_lab);

  /* Set TARGET to zero and branch to the continue label.  */
  emit_move_insn (target, const0_rtx);
  emit_jump_insn (gen_jump (cont_lab));
  emit_barrier ();
  emit_label (next_lab);

  expand_builtin_setjmp_receiver (next_lab);

  /* Set TARGET to one.  */
  emit_move_insn (target, const1_rtx);
  emit_label (cont_lab);

  /* Tell flow about the strange goings on.  Putting `next_lab' on
     `nonlocal_goto_handler_labels' to indicates that function
     calls may traverse the arc back to this label.  */

  current_function_has_nonlocal_label = 1;
  nonlocal_goto_handler_labels
    = gen_rtx_EXPR_LIST (VOIDmode, next_lab, nonlocal_goto_handler_labels);

  return target;
}

/* __builtin_longjmp is passed a pointer to an array of five words (not
   all will be used on all machines).  It operates similarly to the C
   library function of the same name, but is more efficient.  Much of
   the code below is copied from the handling of non-local gotos.

   NOTE: This is intended for use by GNAT and the exception handling
   scheme in the compiler and will only work in the method used by
   them.  */

void
expand_builtin_longjmp (rtx buf_addr, rtx value)
{
  rtx fp, lab, stack, insn, last;
  enum machine_mode sa_mode = STACK_SAVEAREA_MODE (SAVE_NONLOCAL);

  if (setjmp_alias_set == -1)
    setjmp_alias_set = new_alias_set ();

#ifdef POINTERS_EXTEND_UNSIGNED
  if (GET_MODE (buf_addr) != Pmode)
    buf_addr = convert_memory_address (Pmode, buf_addr);
#endif

  buf_addr = force_reg (Pmode, buf_addr);

  /* We used to store value in static_chain_rtx, but that fails if pointers
     are smaller than integers.  We instead require that the user must pass
     a second argument of 1, because that is what builtin_setjmp will
     return.  This also makes EH slightly more efficient, since we are no
     longer copying around a value that we don't care about.  */
  if (value != const1_rtx)
    abort ();

  current_function_calls_longjmp = 1;

  last = get_last_insn ();
#ifdef HAVE_builtin_longjmp
  if (HAVE_builtin_longjmp)
    emit_insn (gen_builtin_longjmp (buf_addr));
  else
#endif
    {
      fp = gen_rtx_MEM (Pmode, buf_addr);
      lab = gen_rtx_MEM (Pmode, plus_constant (buf_addr,
                                               GET_MODE_SIZE (Pmode)));

      stack = gen_rtx_MEM (sa_mode, plus_constant (buf_addr,
                                                   2 * GET_MODE_SIZE (Pmode)));
      set_mem_alias_set (fp, setjmp_alias_set);
      set_mem_alias_set (lab, setjmp_alias_set);
      set_mem_alias_set (stack, setjmp_alias_set);

      /* Pick up FP, label, and SP from the block and jump.  This code is
         from expand_goto in stmt.c; see there for detailed comments.  */
#if HAVE_nonlocal_goto
      if (HAVE_nonlocal_goto)
        /* We have to pass a value to the nonlocal_goto pattern that will
           get copied into the static_chain pointer, but it does not matter
           what that value is, because builtin_setjmp does not use it.  */
        emit_insn (gen_nonlocal_goto (value, lab, stack, fp));
      else
#endif
        {
          lab = copy_to_reg (lab);

          emit_move_insn (hard_frame_pointer_rtx, fp);
          emit_stack_restore (SAVE_NONLOCAL, stack, NULL_RTX);

          emit_insn (gen_rtx_USE (VOIDmode, hard_frame_pointer_rtx));
          emit_insn (gen_rtx_USE (VOIDmode, stack_pointer_rtx));
          emit_indirect_jump (lab);
        }
    }

  /* Search backwards and mark the jump insn as a non-local goto.
     Note that this precludes the use of __builtin_longjmp to a
     __builtin_setjmp target in the same function.  However, we've
     already cautioned the user that these functions are for
     internal exception handling use only.  */
  for (insn = get_last_insn (); insn; insn = PREV_INSN (insn))
    {
      if (insn == last)
        abort ();
      if (GET_CODE (insn) == JUMP_INSN)
        {
          REG_NOTES (insn) = alloc_EXPR_LIST (REG_NON_LOCAL_GOTO, const0_rtx,
                                              REG_NOTES (insn));
          break;
        }
      else if (GET_CODE (insn) == CALL_INSN)
        break;
    }
}

/* Expand a call to __builtin_prefetch.  For a target that does not support
   data prefetch, evaluate the memory address argument in case it has side
   effects.  */

static void
expand_builtin_prefetch (tree arglist)
{
  tree arg0, arg1, arg2;
  rtx op0, op1, op2;

  if (!validate_arglist (arglist, POINTER_TYPE, 0))
    return;

  arg0 = TREE_VALUE (arglist);
  /* Arguments 1 and 2 are optional; argument 1 (read/write) defaults to
     zero (read) and argument 2 (locality) defaults to 3 (high degree of
     locality).  */
  if (TREE_CHAIN (arglist))
    {
      arg1 = TREE_VALUE (TREE_CHAIN (arglist));
      if (TREE_CHAIN (TREE_CHAIN (arglist)))
        arg2 = TREE_VALUE (TREE_CHAIN (TREE_CHAIN (arglist)));
      else
        arg2 = build_int_2 (3, 0);
    }
  else
    {
      arg1 = integer_zero_node;
      arg2 = build_int_2 (3, 0);
    }

  /* Argument 0 is an address.  */
  op0 = expand_expr (arg0, NULL_RTX, Pmode, EXPAND_NORMAL);

  /* Argument 1 (read/write flag) must be a compile-time constant int.  */
  if (TREE_CODE (arg1) != INTEGER_CST)
    {
      error ("second arg to `__builtin_prefetch' must be a constant");
      arg1 = integer_zero_node;
    }
  op1 = expand_expr (arg1, NULL_RTX, VOIDmode, 0);
  /* Argument 1 must be either zero or one.  */
  if (INTVAL (op1) != 0 && INTVAL (op1) != 1)
    {
      warning ("invalid second arg to __builtin_prefetch; using zero");
      op1 = const0_rtx;
    }

  /* Argument 2 (locality) must be a compile-time constant int.  */
  if (TREE_CODE (arg2) != INTEGER_CST)
    {
      error ("third arg to `__builtin_prefetch' must be a constant");
      arg2 = integer_zero_node;
    }
  op2 = expand_expr (arg2, NULL_RTX, VOIDmode, 0);
  /* Argument 2 must be 0, 1, 2, or 3.  */
  if (INTVAL (op2) < 0 || INTVAL (op2) > 3)
    {
      warning ("invalid third arg to __builtin_prefetch; using zero");
      op2 = const0_rtx;
    }

#ifdef HAVE_prefetch
  if (HAVE_prefetch)
    {
      if ((! (*insn_data[(int) CODE_FOR_prefetch].operand[0].predicate)
             (op0,
              insn_data[(int) CODE_FOR_prefetch].operand[0].mode))
          || (GET_MODE (op0) != Pmode))
        {
#ifdef POINTERS_EXTEND_UNSIGNED
          if (GET_MODE (op0) != Pmode)
            op0 = convert_memory_address (Pmode, op0);
#endif
          op0 = force_reg (Pmode, op0);
        }
      emit_insn (gen_prefetch (op0, op1, op2));
    }
  else
#endif
    op0 = protect_from_queue (op0, 0);
  /* Don't do anything with direct references to volatile memory, but
     generate code to handle other side effects.  */
  if (GET_CODE (op0) != MEM && side_effects_p (op0))
    emit_insn (op0);
}

/* Get a MEM rtx for expression EXP which is the address of an operand
   to be used to be used in a string instruction (cmpstrsi, movstrsi, ..).  */

static rtx
get_memory_rtx (tree exp)
{
  rtx addr = expand_expr (exp, NULL_RTX, ptr_mode, EXPAND_SUM);
  rtx mem;

#ifdef POINTERS_EXTEND_UNSIGNED
  if (GET_MODE (addr) != Pmode)
    addr = convert_memory_address (Pmode, addr);
#endif

  mem = gen_rtx_MEM (BLKmode, memory_address (BLKmode, addr));

  /* Get an expression we can use to find the attributes to assign to MEM.
     If it is an ADDR_EXPR, use the operand.  Otherwise, dereference it if
     we can.  First remove any nops.  */
  while ((TREE_CODE (exp) == NOP_EXPR || TREE_CODE (exp) == CONVERT_EXPR
          || TREE_CODE (exp) == NON_LVALUE_EXPR)
         && POINTER_TYPE_P (TREE_TYPE (TREE_OPERAND (exp, 0))))
    exp = TREE_OPERAND (exp, 0);

  if (TREE_CODE (exp) == ADDR_EXPR)
    {
      exp = TREE_OPERAND (exp, 0);
      set_mem_attributes (mem, exp, 0);
    }
  else if (POINTER_TYPE_P (TREE_TYPE (exp)))
    {
      exp = build1 (INDIRECT_REF, TREE_TYPE (TREE_TYPE (exp)), exp);
      /* memcpy, memset and other builtin stringops can alias with anything.  */
      set_mem_alias_set (mem, 0);
    }

  return mem;
}
\f
/* Built-in functions to perform an untyped call and return.  */

/* For each register that may be used for calling a function, this
   gives a mode used to copy the register's value.  VOIDmode indicates
   the register is not used for calling a function.  If the machine
   has register windows, this gives only the outbound registers.
   INCOMING_REGNO gives the corresponding inbound register.  */
static enum machine_mode apply_args_mode[FIRST_PSEUDO_REGISTER];

/* For each register that may be used for returning values, this gives
   a mode used to copy the register's value.  VOIDmode indicates the
   register is not used for returning values.  If the machine has
   register windows, this gives only the outbound registers.
   INCOMING_REGNO gives the corresponding inbound register.  */
static enum machine_mode apply_result_mode[FIRST_PSEUDO_REGISTER];

/* For each register that may be used for calling a function, this
   gives the offset of that register into the block returned by
   __builtin_apply_args.  0 indicates that the register is not
   used for calling a function.  */
static int apply_args_reg_offset[FIRST_PSEUDO_REGISTER];

/* Return the offset of register REGNO into the block returned by
   __builtin_apply_args.  This is not declared static, since it is
   needed in objc-act.c.  */

int
apply_args_register_offset (int regno)
{
  apply_args_size ();

  /* Arguments are always put in outgoing registers (in the argument
     block) if such make sense.  */
#ifdef OUTGOING_REGNO
  regno = OUTGOING_REGNO (regno);
#endif
  return apply_args_reg_offset[regno];
}

/* Return the size required for the block returned by __builtin_apply_args,
   and initialize apply_args_mode.  */

static int
apply_args_size (void)
{
  static int size = -1;
  int align;
  unsigned int regno;
  enum machine_mode mode;

  /* The values computed by this function never change.  */
  if (size < 0)
    {
      /* The first value is the incoming arg-pointer.  */
      size = GET_MODE_SIZE (Pmode);

      /* The second value is the structure value address unless this is
         passed as an "invisible" first argument.  */
      if (struct_value_rtx)
        size += GET_MODE_SIZE (Pmode);

      for (regno = 0; regno < FIRST_PSEUDO_REGISTER; regno++)
        if (FUNCTION_ARG_REGNO_P (regno))
          {
            /* Search for the proper mode for copying this register's
               value.  I'm not sure this is right, but it works so far.  */
            enum machine_mode best_mode = VOIDmode;

            for (mode = GET_CLASS_NARROWEST_MODE (MODE_INT);
                 mode != VOIDmode;
                 mode = GET_MODE_WIDER_MODE (mode))
              if (HARD_REGNO_MODE_OK (regno, mode)
                  && HARD_REGNO_NREGS (regno, mode) == 1)
                best_mode = mode;

            if (best_mode == VOIDmode)
              for (mode = GET_CLASS_NARROWEST_MODE (MODE_FLOAT);
                   mode != VOIDmode;
                   mode = GET_MODE_WIDER_MODE (mode))
                if (HARD_REGNO_MODE_OK (regno, mode)
                    && have_insn_for (SET, mode))
                  best_mode = mode;

            if (best_mode == VOIDmode)
              for (mode = GET_CLASS_NARROWEST_MODE (MODE_VECTOR_FLOAT);
                   mode != VOIDmode;
                   mode = GET_MODE_WIDER_MODE (mode))
                if (HARD_REGNO_MODE_OK (regno, mode)
                    && have_insn_for (SET, mode))
                  best_mode = mode;

            if (best_mode == VOIDmode)
              for (mode = GET_CLASS_NARROWEST_MODE (MODE_VECTOR_INT);
                   mode != VOIDmode;
                   mode = GET_MODE_WIDER_MODE (mode))
                if (HARD_REGNO_MODE_OK (regno, mode)
                    && have_insn_for (SET, mode))
                  best_mode = mode;

            mode = best_mode;
            if (mode == VOIDmode)
              abort ();

            align = GET_MODE_ALIGNMENT (mode) / BITS_PER_UNIT;
            if (size % align != 0)
              size = CEIL (size, align) * align;
            apply_args_reg_offset[regno] = size;
            size += GET_MODE_SIZE (mode);
            apply_args_mode[regno] = mode;
          }
        else
          {
            apply_args_mode[regno] = VOIDmode;
            apply_args_reg_offset[regno] = 0;
          }
    }
  return size;
}

/* Return the size required for the block returned by __builtin_apply,
   and initialize apply_result_mode.  */

static int
apply_result_size (void)
{
  static int size = -1;
  int align, regno;
  enum machine_mode mode;

  /* The values computed by this function never change.  */
  if (size < 0)
    {
      size = 0;

      for (regno = 0; regno < FIRST_PSEUDO_REGISTER; regno++)
        if (FUNCTION_VALUE_REGNO_P (regno))
          {
            /* Search for the proper mode for copying this register's
               value.  I'm not sure this is right, but it works so far.  */
            enum machine_mode best_mode = VOIDmode;

            for (mode = GET_CLASS_NARROWEST_MODE (MODE_INT);
                 mode != TImode;
                 mode = GET_MODE_WIDER_MODE (mode))
              if (HARD_REGNO_MODE_OK (regno, mode))
                best_mode = mode;

            if (best_mode == VOIDmode)
              for (mode = GET_CLASS_NARROWEST_MODE (MODE_FLOAT);
                   mode != VOIDmode;
                   mode = GET_MODE_WIDER_MODE (mode))
                if (HARD_REGNO_MODE_OK (regno, mode)
                    && have_insn_for (SET, mode))
                  best_mode = mode;

            if (best_mode == VOIDmode)
              for (mode = GET_CLASS_NARROWEST_MODE (MODE_VECTOR_FLOAT);
                   mode != VOIDmode;
                   mode = GET_MODE_WIDER_MODE (mode))
                if (HARD_REGNO_MODE_OK (regno, mode)
                    && have_insn_for (SET, mode))
                  best_mode = mode;

            if (best_mode == VOIDmode)
              for (mode = GET_CLASS_NARROWEST_MODE (MODE_VECTOR_INT);
                   mode != VOIDmode;
                   mode = GET_MODE_WIDER_MODE (mode))
                if (HARD_REGNO_MODE_OK (regno, mode)
                    && have_insn_for (SET, mode))
                  best_mode = mode;

            mode = best_mode;
            if (mode == VOIDmode)
              abort ();

            align = GET_MODE_ALIGNMENT (mode) / BITS_PER_UNIT;
            if (size % align != 0)
              size = CEIL (size, align) * align;
            size += GET_MODE_SIZE (mode);
            apply_result_mode[regno] = mode;
          }
        else
          apply_result_mode[regno] = VOIDmode;

      /* Allow targets that use untyped_call and untyped_return to override
         the size so that machine-specific information can be stored here.  */
#ifdef APPLY_RESULT_SIZE
      size = APPLY_RESULT_SIZE;
#endif
    }
  return size;
}

#if defined (HAVE_untyped_call) || defined (HAVE_untyped_return)
/* Create a vector describing the result block RESULT.  If SAVEP is true,
   the result block is used to save the values; otherwise it is used to
   restore the values.  */

static rtx
result_vector (int savep, rtx result)
{
  int regno, size, align, nelts;
  enum machine_mode mode;
  rtx reg, mem;
  rtx *savevec = alloca (FIRST_PSEUDO_REGISTER * sizeof (rtx));

  size = nelts = 0;
  for (regno = 0; regno < FIRST_PSEUDO_REGISTER; regno++)
    if ((mode = apply_result_mode[regno]) != VOIDmode)
      {
        align = GET_MODE_ALIGNMENT (mode) / BITS_PER_UNIT;
        if (size % align != 0)
          size = CEIL (size, align) * align;
        reg = gen_rtx_REG (mode, savep ? regno : INCOMING_REGNO (regno));
        mem = adjust_address (result, mode, size);
        savevec[nelts++] = (savep
                            ? gen_rtx_SET (VOIDmode, mem, reg)
                            : gen_rtx_SET (VOIDmode, reg, mem));
        size += GET_MODE_SIZE (mode);
      }
  return gen_rtx_PARALLEL (VOIDmode, gen_rtvec_v (nelts, savevec));
}
#endif /* HAVE_untyped_call or HAVE_untyped_return */

/* Save the state required to perform an untyped call with the same
   arguments as were passed to the current function.  */

static rtx
expand_builtin_apply_args_1 (void)
{
  rtx registers;
  int size, align, regno;
  enum machine_mode mode;

  /* Create a block where the arg-pointer, structure value address,
     and argument registers can be saved.  */
  registers = assign_stack_local (BLKmode, apply_args_size (), -1);

  /* Walk past the arg-pointer and structure value address.  */
  size = GET_MODE_SIZE (Pmode);
  if (struct_value_rtx)
    size += GET_MODE_SIZE (Pmode);

  /* Save each register used in calling a function to the block.  */
  for (regno = 0; regno < FIRST_PSEUDO_REGISTER; regno++)
    if ((mode = apply_args_mode[regno]) != VOIDmode)
      {
        rtx tem;

        align = GET_MODE_ALIGNMENT (mode) / BITS_PER_UNIT;
        if (size % align != 0)
          size = CEIL (size, align) * align;

        tem = gen_rtx_REG (mode, INCOMING_REGNO (regno));

        emit_move_insn (adjust_address (registers, mode, size), tem);
        size += GET_MODE_SIZE (mode);
      }

  /* Save the arg pointer to the block.  */
  emit_move_insn (adjust_address (registers, Pmode, 0),
                  copy_to_reg (virtual_incoming_args_rtx));
  size = GET_MODE_SIZE (Pmode);

  /* Save the structure value address unless this is passed as an
     "invisible" first argument.  */
  if (struct_value_incoming_rtx)
    {
      emit_move_insn (adjust_address (registers, Pmode, size),
                      copy_to_reg (struct_value_incoming_rtx));
      size += GET_MODE_SIZE (Pmode);
    }

  /* Return the address of the block.  */
  return copy_addr_to_reg (XEXP (registers, 0));
}

/* __builtin_apply_args returns block of memory allocated on
   the stack into which is stored the arg pointer, structure
   value address, static chain, and all the registers that might
   possibly be used in performing a function call.  The code is
   moved to the start of the function so the incoming values are
   saved.  */

static rtx
expand_builtin_apply_args (void)
{
  /* Don't do __builtin_apply_args more than once in a function.
     Save the result of the first call and reuse it.  */
  if (apply_args_value != 0)
    return apply_args_value;
  {
    /* When this function is called, it means that registers must be
       saved on entry to this function.  So we migrate the
       call to the first insn of this function.  */
    rtx temp;
    rtx seq;

    start_sequence ();
    temp = expand_builtin_apply_args_1 ();
    seq = get_insns ();
    end_sequence ();

    apply_args_value = temp;

    /* Put the insns after the NOTE that starts the function.
       If this is inside a start_sequence, make the outer-level insn
       chain current, so the code is placed at the start of the
       function.  */
    push_topmost_sequence ();
    emit_insn_before (seq, NEXT_INSN (get_insns ()));
    pop_topmost_sequence ();
    return temp;
  }
}

/* Perform an untyped call and save the state required to perform an
   untyped return of whatever value was returned by the given function.  */

static rtx
expand_builtin_apply (rtx function, rtx arguments, rtx argsize)
{
  int size, align, regno;
  enum machine_mode mode;
  rtx incoming_args, result, reg, dest, src, call_insn;
  rtx old_stack_level = 0;
  rtx call_fusage = 0;

#ifdef POINTERS_EXTEND_UNSIGNED
  if (GET_MODE (arguments) != Pmode)
    arguments = convert_memory_address (Pmode, arguments);
#endif

  /* Create a block where the return registers can be saved.  */
  result = assign_stack_local (BLKmode, apply_result_size (), -1);

  /* Fetch the arg pointer from the ARGUMENTS block.  */
  incoming_args = gen_reg_rtx (Pmode);
  emit_move_insn (incoming_args, gen_rtx_MEM (Pmode, arguments));
#ifndef STACK_GROWS_DOWNWARD
  incoming_args = expand_simple_binop (Pmode, MINUS, incoming_args, argsize,
                                       incoming_args, 0, OPTAB_LIB_WIDEN);
#endif

  /* Perform postincrements before actually calling the function.  */
  emit_queue ();

  /* Push a new argument block and copy the arguments.  Do not allow
     the (potential) memcpy call below to interfere with our stack
     manipulations.  */
  do_pending_stack_adjust ();
  NO_DEFER_POP;

  /* Save the stack with nonlocal if available.  */
#ifdef HAVE_save_stack_nonlocal
  if (HAVE_save_stack_nonlocal)
    emit_stack_save (SAVE_NONLOCAL, &old_stack_level, NULL_RTX);
  else
#endif
    emit_stack_save (SAVE_BLOCK, &old_stack_level, NULL_RTX);

  /* Push a block of memory onto the stack to store the memory arguments.
     Save the address in a register, and copy the memory arguments.  ??? I
     haven't figured out how the calling convention macros effect this,
     but it's likely that the source and/or destination addresses in
     the block copy will need updating in machine specific ways.  */
  dest = allocate_dynamic_stack_space (argsize, 0, BITS_PER_UNIT);
  dest = gen_rtx_MEM (BLKmode, dest);
  set_mem_align (dest, PARM_BOUNDARY);
  src = gen_rtx_MEM (BLKmode, incoming_args);
  set_mem_align (src, PARM_BOUNDARY);
  emit_block_move (dest, src, argsize, BLOCK_OP_NORMAL);

  /* Refer to the argument block.  */
  apply_args_size ();
  arguments = gen_rtx_MEM (BLKmode, arguments);
  set_mem_align (arguments, PARM_BOUNDARY);

  /* Walk past the arg-pointer and structure value address.  */
  size = GET_MODE_SIZE (Pmode);
  if (struct_value_rtx)
    size += GET_MODE_SIZE (Pmode);

  /* Restore each of the registers previously saved.  Make USE insns
     for each of these registers for use in making the call.  */
  for (regno = 0; regno < FIRST_PSEUDO_REGISTER; regno++)
    if ((mode = apply_args_mode[regno]) != VOIDmode)
      {
        align = GET_MODE_ALIGNMENT (mode) / BITS_PER_UNIT;
        if (size % align != 0)
          size = CEIL (size, align) * align;
        reg = gen_rtx_REG (mode, regno);
        emit_move_insn (reg, adjust_address (arguments, mode, size));
        use_reg (&call_fusage, reg);
        size += GET_MODE_SIZE (mode);
      }

  /* Restore the structure value address unless this is passed as an
     "invisible" first argument.  */
  size = GET_MODE_SIZE (Pmode);
  if (struct_value_rtx)
    {
      rtx value = gen_reg_rtx (Pmode);
      emit_move_insn (value, adjust_address (arguments, Pmode, size));
      emit_move_insn (struct_value_rtx, value);
      if (GET_CODE (struct_value_rtx) == REG)
        use_reg (&call_fusage, struct_value_rtx);
      size += GET_MODE_SIZE (Pmode);
    }

  /* All arguments and registers used for the call are set up by now!  */
  function = prepare_call_address (function, NULL_TREE, &call_fusage, 0, 0);

  /* Ensure address is valid.  SYMBOL_REF is already valid, so no need,
     and we don't want to load it into a register as an optimization,
     because prepare_call_address already did it if it should be done.  */
  if (GET_CODE (function) != SYMBOL_REF)
    function = memory_address (FUNCTION_MODE, function);

  /* Generate the actual call instruction and save the return value.  */
#ifdef HAVE_untyped_call
  if (HAVE_untyped_call)
    emit_call_insn (gen_untyped_call (gen_rtx_MEM (FUNCTION_MODE, function),
                                      result, result_vector (1, result)));
  else
#endif
#ifdef HAVE_call_value
  if (HAVE_call_value)
    {
      rtx valreg = 0;

      /* Locate the unique return register.  It is not possible to
         express a call that sets more than one return register using
         call_value; use untyped_call for that.  In fact, untyped_call
         only needs to save the return registers in the given block.  */
      for (regno = 0; regno < FIRST_PSEUDO_REGISTER; regno++)
        if ((mode = apply_result_mode[regno]) != VOIDmode)
          {
            if (valreg)
              abort (); /* HAVE_untyped_call required.  */
            valreg = gen_rtx_REG (mode, regno);
          }

      emit_call_insn (GEN_CALL_VALUE (valreg,
                                      gen_rtx_MEM (FUNCTION_MODE, function),
                                      const0_rtx, NULL_RTX, const0_rtx));

      emit_move_insn (adjust_address (result, GET_MODE (valreg), 0), valreg);
    }
  else
#endif
    abort ();

  /* Find the CALL insn we just emitted, and attach the register usage
     information.  */
  call_insn = last_call_insn ();
  add_function_usage_to (call_insn, call_fusage);

  /* Restore the stack.  */
#ifdef HAVE_save_stack_nonlocal
  if (HAVE_save_stack_nonlocal)
    emit_stack_restore (SAVE_NONLOCAL, old_stack_level, NULL_RTX);
  else
#endif
    emit_stack_restore (SAVE_BLOCK, old_stack_level, NULL_RTX);

  OK_DEFER_POP;

  /* Return the address of the result block.  */
  return copy_addr_to_reg (XEXP (result, 0));
}

/* Perform an untyped return.  */

static void
expand_builtin_return (rtx result)
{
  int size, align, regno;
  enum machine_mode mode;
  rtx reg;
  rtx call_fusage = 0;

#ifdef POINTERS_EXTEND_UNSIGNED
  if (GET_MODE (result) != Pmode)
    result = convert_memory_address (Pmode, result);
#endif

  apply_result_size ();
  result = gen_rtx_MEM (BLKmode, result);

#ifdef HAVE_untyped_return
  if (HAVE_untyped_return)
    {
      emit_jump_insn (gen_untyped_return (result, result_vector (0, result)));
      emit_barrier ();
      return;
    }
#endif

  /* Restore the return value and note that each value is used.  */
  size = 0;
  for (regno = 0; regno < FIRST_PSEUDO_REGISTER; regno++)
    if ((mode = apply_result_mode[regno]) != VOIDmode)
      {
        align = GET_MODE_ALIGNMENT (mode) / BITS_PER_UNIT;
        if (size % align != 0)
          size = CEIL (size, align) * align;
        reg = gen_rtx_REG (mode, INCOMING_REGNO (regno));
        emit_move_insn (reg, adjust_address (result, mode, size));

        push_to_sequence (call_fusage);
        emit_insn (gen_rtx_USE (VOIDmode, reg));
        call_fusage = get_insns ();
        end_sequence ();
        size += GET_MODE_SIZE (mode);
      }

  /* Put the USE insns before the return.  */
  emit_insn (call_fusage);

  /* Return whatever values was restored by jumping directly to the end
     of the function.  */
  expand_null_return ();
}

/* Used by expand_builtin_classify_type and fold_builtin_classify_type.  */

static enum type_class
type_to_class (tree type)
{
  switch (TREE_CODE (type))
    {
    case VOID_TYPE:        return void_type_class;
    case INTEGER_TYPE:     return integer_type_class;
    case CHAR_TYPE:        return char_type_class;
    case ENUMERAL_TYPE:    return enumeral_type_class;
    case BOOLEAN_TYPE:     return boolean_type_class;
    case POINTER_TYPE:     return pointer_type_class;
    case REFERENCE_TYPE:   return reference_type_class;
    case OFFSET_TYPE:      return offset_type_class;
    case REAL_TYPE:        return real_type_class;
    case COMPLEX_TYPE:     return complex_type_class;
    case FUNCTION_TYPE:    return function_type_class;
    case METHOD_TYPE:      return method_type_class;
    case RECORD_TYPE:      return record_type_class;
    case UNION_TYPE:
    case QUAL_UNION_TYPE:  return union_type_class;
    case ARRAY_TYPE:       return (TYPE_STRING_FLAG (type)
                                   ? string_type_class : array_type_class);
    case SET_TYPE:         return set_type_class;
    case FILE_TYPE:        return file_type_class;
    case LANG_TYPE:        return lang_type_class;
    default:               return no_type_class;
    }
}

/* Expand a call to __builtin_classify_type with arguments found in
   ARGLIST.  */

static rtx
expand_builtin_classify_type (tree arglist)
{
  if (arglist != 0)
    return GEN_INT (type_to_class (TREE_TYPE (TREE_VALUE (arglist))));
  return GEN_INT (no_type_class);
}

/* Expand expression EXP, which is a call to __builtin_constant_p.  */

static rtx
expand_builtin_constant_p (tree arglist, enum machine_mode target_mode)
{
  rtx tmp;

  if (arglist == 0)
    return const0_rtx;
  arglist = TREE_VALUE (arglist);

  /* We have taken care of the easy cases during constant folding.  This
     case is not obvious, so emit (constant_p_rtx (ARGLIST)) and let CSE
     get a chance to see if it can deduce whether ARGLIST is constant.  */

  current_function_calls_constant_p = 1;

  tmp = expand_expr (arglist, NULL_RTX, VOIDmode, 0);
  tmp = gen_rtx_CONSTANT_P_RTX (target_mode, tmp);
  return tmp;
}

/* This helper macro, meant to be used in mathfn_built_in below,
   determines which among a set of three builtin math functions is
   appropriate for a given type mode.  The `F' and `L' cases are
   automatically generated from the `double' case.  */
#define CASE_MATHFN(BUILT_IN_MATHFN) \
  case BUILT_IN_MATHFN: case BUILT_IN_MATHFN##F: case BUILT_IN_MATHFN##L: \
  fcode = BUILT_IN_MATHFN; fcodef = BUILT_IN_MATHFN##F ; \
  fcodel = BUILT_IN_MATHFN##L ; break;

/* Return mathematic function equivalent to FN but operating directly
   on TYPE, if available.  If we can't do the conversion, return zero.  */
tree
mathfn_built_in (tree type, enum built_in_function fn)
{
  const enum machine_mode type_mode = TYPE_MODE (type);
  enum built_in_function fcode, fcodef, fcodel;

  switch (fn)
    {
      CASE_MATHFN (BUILT_IN_ATAN)
      CASE_MATHFN (BUILT_IN_CEIL)
      CASE_MATHFN (BUILT_IN_COS)
      CASE_MATHFN (BUILT_IN_EXP)
      CASE_MATHFN (BUILT_IN_FLOOR)
      CASE_MATHFN (BUILT_IN_LOG)
      CASE_MATHFN (BUILT_IN_NEARBYINT)
      CASE_MATHFN (BUILT_IN_ROUND)
      CASE_MATHFN (BUILT_IN_SIN)
      CASE_MATHFN (BUILT_IN_SQRT)
      CASE_MATHFN (BUILT_IN_TAN)
      CASE_MATHFN (BUILT_IN_TRUNC)

      default:
        return 0;
      }

  if (type_mode == TYPE_MODE (double_type_node))
    return implicit_built_in_decls[fcode];
  else if (type_mode == TYPE_MODE (float_type_node))
    return implicit_built_in_decls[fcodef];
  else if (type_mode == TYPE_MODE (long_double_type_node))
    return implicit_built_in_decls[fcodel];
  else
    return 0;
}

/* If errno must be maintained, expand the RTL to check if the result,
   TARGET, of a built-in function call, EXP, is NaN, and if so set
   errno to EDOM.  */

static void
expand_errno_check (tree exp, rtx target)
{
  rtx lab = gen_label_rtx ();

  /* Test the result; if it is NaN, set errno=EDOM because
     the argument was not in the domain.  */
  emit_cmp_and_jump_insns (target, target, EQ, 0, GET_MODE (target),
                           0, lab);

#ifdef TARGET_EDOM
  /* If this built-in doesn't throw an exception, set errno directly.  */
  if (TREE_NOTHROW (TREE_OPERAND (TREE_OPERAND (exp, 0), 0)))
    {
#ifdef GEN_ERRNO_RTX
      rtx errno_rtx = GEN_ERRNO_RTX;
#else
      rtx errno_rtx
          = gen_rtx_MEM (word_mode, gen_rtx_SYMBOL_REF (Pmode, "errno"));
#endif
      emit_move_insn (errno_rtx, GEN_INT (TARGET_EDOM));
      emit_label (lab);
      return;
    }
#endif

  /* We can't set errno=EDOM directly; let the library call do it.
     Pop the arguments right away in case the call gets deleted.  */
  NO_DEFER_POP;
  expand_call (exp, target, 0);
  OK_DEFER_POP;
  emit_label (lab);
}


/* Expand a call to one of the builtin math functions (sin, cos, or sqrt).
   Return 0 if a normal call should be emitted rather than expanding the
   function in-line.  EXP is the expression that is a call to the builtin
   function; if convenient, the result should be placed in TARGET.
   SUBTARGET may be used as the target for computing one of EXP's operands.  */

static rtx
expand_builtin_mathfn (tree exp, rtx target, rtx subtarget)
{
  optab builtin_optab;
  rtx op0, insns;
  tree fndecl = TREE_OPERAND (TREE_OPERAND (exp, 0), 0);
  tree arglist = TREE_OPERAND (exp, 1);
  enum machine_mode mode;
  bool errno_set = false;
  tree arg, narg;

  if (!validate_arglist (arglist, REAL_TYPE, VOID_TYPE))
    return 0;

  arg = TREE_VALUE (arglist);

  switch (DECL_FUNCTION_CODE (fndecl))
    {
    case BUILT_IN_SIN:
    case BUILT_IN_SINF:
    case BUILT_IN_SINL:
      builtin_optab = sin_optab; break;
    case BUILT_IN_COS:
    case BUILT_IN_COSF:
    case BUILT_IN_COSL:
      builtin_optab = cos_optab; break;
    case BUILT_IN_SQRT:
    case BUILT_IN_SQRTF:
    case BUILT_IN_SQRTL:
      errno_set = ! tree_expr_nonnegative_p (arg);
      builtin_optab = sqrt_optab;
      break;
    case BUILT_IN_EXP:
    case BUILT_IN_EXPF:
    case BUILT_IN_EXPL:
      errno_set = true; builtin_optab = exp_optab; break;
    case BUILT_IN_LOG:
    case BUILT_IN_LOGF:
    case BUILT_IN_LOGL:
      errno_set = true; builtin_optab = log_optab; break;
    case BUILT_IN_TAN:
    case BUILT_IN_TANF:
    case BUILT_IN_TANL:
      builtin_optab = tan_optab; break;
    case BUILT_IN_ATAN:
    case BUILT_IN_ATANF:
    case BUILT_IN_ATANL:
      builtin_optab = atan_optab; break;
    case BUILT_IN_FLOOR:
    case BUILT_IN_FLOORF:
    case BUILT_IN_FLOORL:
      builtin_optab = floor_optab; break;
    case BUILT_IN_CEIL:
    case BUILT_IN_CEILF:
    case BUILT_IN_CEILL:
      builtin_optab = ceil_optab; break;
    case BUILT_IN_TRUNC:
    case BUILT_IN_TRUNCF:
    case BUILT_IN_TRUNCL:
      builtin_optab = trunc_optab; break;
    case BUILT_IN_ROUND:
    case BUILT_IN_ROUNDF:
    case BUILT_IN_ROUNDL:
      builtin_optab = round_optab; break;
    case BUILT_IN_NEARBYINT:
    case BUILT_IN_NEARBYINTF:
    case BUILT_IN_NEARBYINTL:
      builtin_optab = nearbyint_optab; break;
    default:
      abort ();
    }

  /* Make a suitable register to place result in.  */
  mode = TYPE_MODE (TREE_TYPE (exp));

  /* Before working hard, check whether the instruction is available.  */
  if (builtin_optab->handlers[(int) mode].insn_code == CODE_FOR_nothing)
    return 0;
  target = gen_reg_rtx (mode);

  if (! flag_errno_math || ! HONOR_NANS (mode))
    errno_set = false;

  /* Wrap the computation of the argument in a SAVE_EXPR, as we may
     need to expand the argument again.  This way, we will not perform
     side-effects more the once.  */
  narg = save_expr (arg);
  if (narg != arg)
    {
      arglist = build_tree_list (NULL_TREE, arg);
      exp = build_function_call_expr (fndecl, arglist);
    }

  op0 = expand_expr (arg, subtarget, VOIDmode, 0);

  emit_queue ();
  start_sequence ();

  /* Compute into TARGET.
     Set TARGET to wherever the result comes back.  */
  target = expand_unop (mode, builtin_optab, op0, target, 0);

  /* If we were unable to expand via the builtin, stop the sequence
     (without outputting the insns) and call to the library function
     with the stabilized argument list.  */
  if (target == 0)
    {
      end_sequence ();
      return expand_call (exp, target, target == const0_rtx);
    }

  if (errno_set)
    expand_errno_check (exp, target);

  /* Output the entire sequence.  */
  insns = get_insns ();
  end_sequence ();
  emit_insn (insns);

  return target;
}

/* Expand a call to the builtin binary math functions (pow and atan2).
   Return 0 if a normal call should be emitted rather than expanding the
   function in-line.  EXP is the expression that is a call to the builtin
   function; if convenient, the result should be placed in TARGET.
   SUBTARGET may be used as the target for computing one of EXP's
   operands.  */

static rtx
expand_builtin_mathfn_2 (tree exp, rtx target, rtx subtarget)
{
  optab builtin_optab;
  rtx op0, op1, insns;
  tree fndecl = TREE_OPERAND (TREE_OPERAND (exp, 0), 0);
  tree arglist = TREE_OPERAND (exp, 1);
  tree arg0, arg1, temp, narg;
  enum machine_mode mode;
  bool errno_set = true;
  bool stable = true;

  if (!validate_arglist (arglist, REAL_TYPE, REAL_TYPE, VOID_TYPE))
    return 0;

  arg0 = TREE_VALUE (arglist);
  arg1 = TREE_VALUE (TREE_CHAIN (arglist));

  switch (DECL_FUNCTION_CODE (fndecl))
    {
    case BUILT_IN_POW:
    case BUILT_IN_POWF:
    case BUILT_IN_POWL:
      builtin_optab = pow_optab; break;
    case BUILT_IN_ATAN2:
    case BUILT_IN_ATAN2F:
    case BUILT_IN_ATAN2L:
      builtin_optab = atan2_optab; break;
    default:
      abort ();
    }

  /* Make a suitable register to place result in.  */
  mode = TYPE_MODE (TREE_TYPE (exp));

  /* Before working hard, check whether the instruction is available.  */
  if (builtin_optab->handlers[(int) mode].insn_code == CODE_FOR_nothing)
    return 0;

  target = gen_reg_rtx (mode);

  if (! flag_errno_math || ! HONOR_NANS (mode))
    errno_set = false;

  /* Alway stabilize the argument list.  */
  narg = save_expr (arg1);
  if (narg != arg1)
    {
      temp = build_tree_list (NULL_TREE, narg);
      stable = false;
    }
  else
    temp = TREE_CHAIN (arglist);

  narg = save_expr (arg0);
  if (narg != arg0)
    {
      arglist = tree_cons (NULL_TREE, narg, temp);
      stable = false;
    }
  else if (! stable)
    arglist = tree_cons (NULL_TREE, arg0, temp);

  if (! stable)
    exp = build_function_call_expr (fndecl, arglist);

  op0 = expand_expr (arg0, subtarget, VOIDmode, 0);
  op1 = expand_expr (arg1, 0, VOIDmode, 0);

  emit_queue ();
  start_sequence ();

  /* Compute into TARGET.
     Set TARGET to wherever the result comes back.  */
  target = expand_binop (mode, builtin_optab, op0, op1,
                         target, 0, OPTAB_DIRECT);

  /* If we were unable to expand via the builtin, stop the sequence
     (without outputting the insns) and call to the library function
     with the stabilized argument list.  */
  if (target == 0)
    {
      end_sequence ();
      return expand_call (exp, target, target == const0_rtx);
    }

  if (errno_set)
    expand_errno_check (exp, target);

  /* Output the entire sequence.  */
  insns = get_insns ();
  end_sequence ();
  emit_insn (insns);

  return target;
}

/* To evaluate powi(x,n), the floating point value x raised to the
   constant integer exponent n, we use a hybrid algorithm that
   combines the "window method" with look-up tables.  For an
   introduction to exponentiation algorithms and "addition chains",
   see section 4.6.3, "Evaluation of Powers" of Donald E. Knuth,
   "Seminumerical Algorithms", Vol. 2, "The Art of Computer Programming",
   3rd Edition, 1998, and Daniel M. Gordon, "A Survey of Fast Exponentiation
   Methods", Journal of Algorithms, Vol. 27, pp. 129-146, 1998.  */

/* Provide a default value for POWI_MAX_MULTS, the maximum number of
   multiplications to inline before calling the system library's pow
   function.  powi(x,n) requires at worst 2*bits(n)-2 multiplications,
   so this default never requires calling pow, powf or powl.  */
 
#ifndef POWI_MAX_MULTS
#define POWI_MAX_MULTS  (2*HOST_BITS_PER_WIDE_INT-2)
#endif

/* The size of the "optimal power tree" lookup table.  All
   exponents less than this value are simply looked up in the
   powi_table below.  This threshold is also used to size the
   cache of pseudo registers that hold intermediate results.  */
#define POWI_TABLE_SIZE 256

/* The size, in bits of the window, used in the "window method"
   exponentiation algorithm.  This is equivalent to a radix of
   (1<<POWI_WINDOW_SIZE) in the corresponding "m-ary method".  */
#define POWI_WINDOW_SIZE 3

/* The following table is an efficient representation of an
   "optimal power tree".  For each value, i, the corresponding
   value, j, in the table states than an optimal evaluation
   sequence for calculating pow(x,i) can be found by evaluating
   pow(x,j)*pow(x,i-j).  An optimal power tree for the first
   100 integers is given in Knuth's "Seminumerical algorithms".  */

static const unsigned char powi_table[POWI_TABLE_SIZE] =
  {
      0,   1,   1,   2,   2,   3,   3,   4,  /*   0 -   7 */
      4,   6,   5,   6,   6,  10,   7,   9,  /*   8 -  15 */
      8,  16,   9,  16,  10,  12,  11,  13,  /*  16 -  23 */
     12,  17,  13,  18,  14,  24,  15,  26,  /*  24 -  31 */
     16,  17,  17,  19,  18,  33,  19,  26,  /*  32 -  39 */
     20,  25,  21,  40,  22,  27,  23,  44,  /*  40 -  47 */
     24,  32,  25,  34,  26,  29,  27,  44,  /*  48 -  55 */
     28,  31,  29,  34,  30,  60,  31,  36,  /*  56 -  63 */
     32,  64,  33,  34,  34,  46,  35,  37,  /*  64 -  71 */
     36,  65,  37,  50,  38,  48,  39,  69,  /*  72 -  79 */
     40,  49,  41,  43,  42,  51,  43,  58,  /*  80 -  87 */
     44,  64,  45,  47,  46,  59,  47,  76,  /*  88 -  95 */
     48,  65,  49,  66,  50,  67,  51,  66,  /*  96 - 103 */
     52,  70,  53,  74,  54, 104,  55,  74,  /* 104 - 111 */
     56,  64,  57,  69,  58,  78,  59,  68,  /* 112 - 119 */
     60,  61,  61,  80,  62,  75,  63,  68,  /* 120 - 127 */
     64,  65,  65, 128,  66, 129,  67,  90,  /* 128 - 135 */
     68,  73,  69, 131,  70,  94,  71,  88,  /* 136 - 143 */
     72, 128,  73,  98,  74, 132,  75, 121,  /* 144 - 151 */
     76, 102,  77, 124,  78, 132,  79, 106,  /* 152 - 159 */
     80,  97,  81, 160,  82,  99,  83, 134,  /* 160 - 167 */
     84,  86,  85,  95,  86, 160,  87, 100,  /* 168 - 175 */
     88, 113,  89,  98,  90, 107,  91, 122,  /* 176 - 183 */
     92, 111,  93, 102,  94, 126,  95, 150,  /* 184 - 191 */
     96, 128,  97, 130,  98, 133,  99, 195,  /* 192 - 199 */
    100, 128, 101, 123, 102, 164, 103, 138,  /* 200 - 207 */
    104, 145, 105, 146, 106, 109, 107, 149,  /* 208 - 215 */
    108, 200, 109, 146, 110, 170, 111, 157,  /* 216 - 223 */
    112, 128, 113, 130, 114, 182, 115, 132,  /* 224 - 231 */
    116, 200, 117, 132, 118, 158, 119, 206,  /* 232 - 239 */
    120, 240, 121, 162, 122, 147, 123, 152,  /* 240 - 247 */
    124, 166, 125, 214, 126, 138, 127, 153,  /* 248 - 255 */
  };


/* Return the number of multiplications required to calculate
   powi(x,n) where n is less than POWI_TABLE_SIZE.  This is a
   subroutine of powi_cost.  CACHE is an array indicating
   which exponents have already been calculated.  */

static int
powi_lookup_cost (unsigned HOST_WIDE_INT n, bool *cache)
{
  /* If we've already calculated this exponent, then this evaluation
     doesn't require any additional multiplications.  */
  if (cache[n])
    return 0;

  cache[n] = true;
  return powi_lookup_cost (n - powi_table[n], cache)
         + powi_lookup_cost (powi_table[n], cache) + 1;
}

/* Return the number of multiplications required to calculate
   powi(x,n) for an arbitrary x, given the exponent N.  This
   function needs to be kept in sync with expand_powi below.  */

static int
powi_cost (HOST_WIDE_INT n)
{
  bool cache[POWI_TABLE_SIZE];
  unsigned HOST_WIDE_INT digit;
  unsigned HOST_WIDE_INT val;
  int result;

  if (n == 0)
    return 0;

  /* Ignore the reciprocal when calculating the cost.  */
  val = (n < 0) ? -n : n;

  /* Initialize the exponent cache.  */
  memset (cache, 0, POWI_TABLE_SIZE * sizeof (bool));
  cache[1] = true;

  result = 0;

  while (val >= POWI_TABLE_SIZE)
    {
      if (val & 1)
        {
          digit = val & ((1 << POWI_WINDOW_SIZE) - 1);
          result += powi_lookup_cost (digit, cache)
                    + POWI_WINDOW_SIZE + 1;
          val >>= POWI_WINDOW_SIZE;
        }
      else
        {
          val >>= 1;
          result++;
        }
    }
  
  return result + powi_lookup_cost (val, cache);
}

/* Recursive subroutine of expand_powi.  This function takes the array,
   CACHE, of already calculated exponents and an exponent N and returns
   an RTX that corresponds to CACHE[1]**N, as calculated in mode MODE.  */

static rtx
expand_powi_1 (enum machine_mode mode, unsigned HOST_WIDE_INT n, rtx *cache)
{
  unsigned HOST_WIDE_INT digit;
  rtx target, result;
  rtx op0, op1;

  if (n < POWI_TABLE_SIZE)
    {
      if (cache[n])
        return cache[n];

      target = gen_reg_rtx (mode);
      cache[n] = target;

      op0 = expand_powi_1 (mode, n - powi_table[n], cache);
      op1 = expand_powi_1 (mode, powi_table[n], cache);
    }
  else if (n & 1)
    {
      target = gen_reg_rtx (mode);
      digit = n & ((1 << POWI_WINDOW_SIZE) - 1);
      op0 = expand_powi_1 (mode, n - digit, cache);
      op1 = expand_powi_1 (mode, digit, cache);
    }
  else
    {
      target = gen_reg_rtx (mode);
      op0 = expand_powi_1 (mode, n >> 1, cache);
      op1 = op0;
    }

  result = expand_mult (mode, op0, op1, target, 0);
  if (result != target)
    emit_move_insn (target, result);
  return target;
}

/* Expand the RTL to evaluate powi(x,n) in mode MODE.  X is the
   floating point operand in mode MODE, and N is the exponent.  This
   function needs to be kept in sync with powi_cost above.  */
   
static rtx
expand_powi (rtx x, enum machine_mode mode, HOST_WIDE_INT n)
{
  unsigned HOST_WIDE_INT val;
  rtx cache[POWI_TABLE_SIZE];
  rtx result;

  if (n == 0)
    return CONST1_RTX (mode);

  val = (n < 0) ? -n : n;

  memset (cache, 0, sizeof (cache));
  cache[1] = x;

  result = expand_powi_1 (mode, (n < 0) ? -n : n, cache);

  /* If the original exponent was negative, reciprocate the result.  */
  if (n < 0)
    result = expand_binop (mode, sdiv_optab, CONST1_RTX (mode),
                           result, NULL_RTX, 0, OPTAB_LIB_WIDEN);

  return result;
}

/* Expand a call to the pow built-in mathematical function.  Return 0 if
   a normal call should be emitted rather than expanding the function
   in-line.  EXP is the expression that is a call to the builtin
   function; if convenient, the result should be placed in TARGET.  */

static rtx
expand_builtin_pow (tree exp, rtx target, rtx subtarget)
{
  tree arglist = TREE_OPERAND (exp, 1);
  tree arg0, arg1;

  if (! validate_arglist (arglist, REAL_TYPE, REAL_TYPE, VOID_TYPE))
    return 0;

  arg0 = TREE_VALUE (arglist);
  arg1 = TREE_VALUE (TREE_CHAIN (arglist));

  if (TREE_CODE (arg1) == REAL_CST
      && ! TREE_CONSTANT_OVERFLOW (arg1))
    {
      REAL_VALUE_TYPE cint;
      REAL_VALUE_TYPE c;
      HOST_WIDE_INT n;

      c = TREE_REAL_CST (arg1);
      n = real_to_integer (&c);
      real_from_integer (&cint, VOIDmode, n, n < 0 ? -1 : 0, 0);
      if (real_identical (&c, &cint))
        {
          /* If the exponent is -1, 0, 1 or 2, then expand_powi is exact.
             Otherwise, check the number of multiplications required.
             Note that pow never sets errno for an integer exponent.  */
          if ((n >= -1 && n <= 2)
              || (flag_unsafe_math_optimizations
                  && ! optimize_size
                  && powi_cost (n) <= POWI_MAX_MULTS))
            {
              enum machine_mode mode = TYPE_MODE (TREE_TYPE (exp));
              rtx op = expand_expr (arg0, subtarget, VOIDmode, 0);
              op = force_reg (mode, op);
              return expand_powi (op, mode, n);
            }
        }
    }
  return expand_builtin_mathfn_2 (exp, target, NULL_RTX);
}

/* Expand expression EXP which is a call to the strlen builtin.  Return 0
   if we failed the caller should emit a normal call, otherwise
   try to get the result in TARGET, if convenient.  */

static rtx
expand_builtin_strlen (tree arglist, rtx target,
                       enum machine_mode target_mode)
{
  if (!validate_arglist (arglist, POINTER_TYPE, VOID_TYPE))
    return 0;
  else
    {
      rtx pat;
      tree len, src = TREE_VALUE (arglist);
      rtx result, src_reg, char_rtx, before_strlen;
      enum machine_mode insn_mode = target_mode, char_mode;
      enum insn_code icode = CODE_FOR_nothing;
      int align;

      /* If the length can be computed at compile-time, return it.  */
      len = c_strlen (src, 0);
      if (len)
        return expand_expr (len, target, target_mode, EXPAND_NORMAL);

      /* If the length can be computed at compile-time and is constant
         integer, but there are side-effects in src, evaluate
         src for side-effects, then return len.
         E.g. x = strlen (i++ ? "xfoo" + 1 : "bar");
         can be optimized into: i++; x = 3;  */
      len = c_strlen (src, 1);
      if (len && TREE_CODE (len) == INTEGER_CST)
        {
          expand_expr (src, const0_rtx, VOIDmode, EXPAND_NORMAL);
          return expand_expr (len, target, target_mode, EXPAND_NORMAL);
        }

      align = get_pointer_alignment (src, BIGGEST_ALIGNMENT) / BITS_PER_UNIT;

      /* If SRC is not a pointer type, don't do this operation inline.  */
      if (align == 0)
        return 0;

      /* Bail out if we can't compute strlen in the right mode.  */
      while (insn_mode != VOIDmode)
        {
          icode = strlen_optab->handlers[(int) insn_mode].insn_code;
          if (icode != CODE_FOR_nothing)
            break;

          insn_mode = GET_MODE_WIDER_MODE (insn_mode);
        }
      if (insn_mode == VOIDmode)
        return 0;

      /* Make a place to write the result of the instruction.  */
      result = target;
      if (! (result != 0
             && GET_CODE (result) == REG
             && GET_MODE (result) == insn_mode
             && REGNO (result) >= FIRST_PSEUDO_REGISTER))
        result = gen_reg_rtx (insn_mode);

      /* Make a place to hold the source address.  We will not expand
         the actual source until we are sure that the expansion will
         not fail -- there are trees that cannot be expanded twice.  */
      src_reg = gen_reg_rtx (Pmode);

      /* Mark the beginning of the strlen sequence so we can emit the
         source operand later.  */
      before_strlen = get_last_insn ();

      char_rtx = const0_rtx;
      char_mode = insn_data[(int) icode].operand[2].mode;
      if (! (*insn_data[(int) icode].operand[2].predicate) (char_rtx,
                                                            char_mode))
        char_rtx = copy_to_mode_reg (char_mode, char_rtx);

      pat = GEN_FCN (icode) (result, gen_rtx_MEM (BLKmode, src_reg),
                             char_rtx, GEN_INT (align));
      if (! pat)
        return 0;
      emit_insn (pat);

      /* Now that we are assured of success, expand the source.  */
      start_sequence ();
      pat = memory_address (BLKmode,
                            expand_expr (src, src_reg, ptr_mode, EXPAND_SUM));
      if (pat != src_reg)
        emit_move_insn (src_reg, pat);
      pat = get_insns ();
      end_sequence ();

      if (before_strlen)
        emit_insn_after (pat, before_strlen);
      else
        emit_insn_before (pat, get_insns ());

      /* Return the value in the proper mode for this function.  */
      if (GET_MODE (result) == target_mode)
        target = result;
      else if (target != 0)
        convert_move (target, result, 0);
      else
        target = convert_to_mode (target_mode, result, 0);

      return target;
    }
}

/* Expand a call to the strstr builtin.  Return 0 if we failed the
   caller should emit a normal call, otherwise try to get the result
   in TARGET, if convenient (and in mode MODE if that's convenient).  */

static rtx
expand_builtin_strstr (tree arglist, rtx target, enum machine_mode mode)
{
  if (!validate_arglist (arglist, POINTER_TYPE, POINTER_TYPE, VOID_TYPE))
    return 0;
  else
    {
      tree s1 = TREE_VALUE (arglist), s2 = TREE_VALUE (TREE_CHAIN (arglist));
      tree fn;
      const char *p1, *p2;

      p2 = c_getstr (s2);
      if (p2 == NULL)
        return 0;

      p1 = c_getstr (s1);
      if (p1 != NULL)
        {
          const char *r = strstr (p1, p2);

          if (r == NULL)
            return const0_rtx;

          /* Return an offset into the constant string argument.  */
          return expand_expr (fold (build (PLUS_EXPR, TREE_TYPE (s1),
                                           s1, ssize_int (r - p1))),
                              target, mode, EXPAND_NORMAL);
        }

      if (p2[0] == '\0')
        return expand_expr (s1, target, mode, EXPAND_NORMAL);

      if (p2[1] != '\0')
        return 0;

      fn = implicit_built_in_decls[BUILT_IN_STRCHR];
      if (!fn)
        return 0;

      /* New argument list transforming strstr(s1, s2) to
         strchr(s1, s2[0]).  */
      arglist =
        build_tree_list (NULL_TREE, build_int_2 (p2[0], 0));
      arglist = tree_cons (NULL_TREE, s1, arglist);
      return expand_expr (build_function_call_expr (fn, arglist),
                          target, mode, EXPAND_NORMAL);
    }
}

/* Expand a call to the strchr builtin.  Return 0 if we failed the
   caller should emit a normal call, otherwise try to get the result
   in TARGET, if convenient (and in mode MODE if that's convenient).  */

static rtx
expand_builtin_strchr (tree arglist, rtx target, enum machine_mode mode)
{
  if (!validate_arglist (arglist, POINTER_TYPE, INTEGER_TYPE, VOID_TYPE))
    return 0;
  else
    {
      tree s1 = TREE_VALUE (arglist), s2 = TREE_VALUE (TREE_CHAIN (arglist));
      const char *p1;

      if (TREE_CODE (s2) != INTEGER_CST)
        return 0;

      p1 = c_getstr (s1);
      if (p1 != NULL)
        {
          char c;
          const char *r;

          if (target_char_cast (s2, &c))
            return 0;

          r = strchr (p1, c);

          if (r == NULL)
            return const0_rtx;

          /* Return an offset into the constant string argument.  */
          return expand_expr (fold (build (PLUS_EXPR, TREE_TYPE (s1),
                                           s1, ssize_int (r - p1))),
                              target, mode, EXPAND_NORMAL);
        }

      /* FIXME: Should use here strchrM optab so that ports can optimize
         this.  */
      return 0;
    }
}

/* Expand a call to the strrchr builtin.  Return 0 if we failed the
   caller should emit a normal call, otherwise try to get the result
   in TARGET, if convenient (and in mode MODE if that's convenient).  */

static rtx
expand_builtin_strrchr (tree arglist, rtx target, enum machine_mode mode)
{
  if (!validate_arglist (arglist, POINTER_TYPE, INTEGER_TYPE, VOID_TYPE))
    return 0;
  else
    {
      tree s1 = TREE_VALUE (arglist), s2 = TREE_VALUE (TREE_CHAIN (arglist));
      tree fn;
      const char *p1;

      if (TREE_CODE (s2) != INTEGER_CST)
        return 0;

      p1 = c_getstr (s1);
      if (p1 != NULL)
        {
          char c;
          const char *r;

          if (target_char_cast (s2, &c))
            return 0;

          r = strrchr (p1, c);

          if (r == NULL)
            return const0_rtx;

          /* Return an offset into the constant string argument.  */
          return expand_expr (fold (build (PLUS_EXPR, TREE_TYPE (s1),
                                           s1, ssize_int (r - p1))),
                              target, mode, EXPAND_NORMAL);
        }

      if (! integer_zerop (s2))
        return 0;

      fn = implicit_built_in_decls[BUILT_IN_STRCHR];
      if (!fn)
        return 0;

      /* Transform strrchr(s1, '\0') to strchr(s1, '\0').  */
      return expand_expr (build_function_call_expr (fn, arglist),
                          target, mode, EXPAND_NORMAL);
    }
}

/* Expand a call to the strpbrk builtin.  Return 0 if we failed the
   caller should emit a normal call, otherwise try to get the result
   in TARGET, if convenient (and in mode MODE if that's convenient).  */

static rtx
expand_builtin_strpbrk (tree arglist, rtx target, enum machine_mode mode)
{
  if (!validate_arglist (arglist, POINTER_TYPE, POINTER_TYPE, VOID_TYPE))
    return 0;
  else
    {
      tree s1 = TREE_VALUE (arglist), s2 = TREE_VALUE (TREE_CHAIN (arglist));
      tree fn;
      const char *p1, *p2;

      p2 = c_getstr (s2);
      if (p2 == NULL)
        return 0;

      p1 = c_getstr (s1);
      if (p1 != NULL)
        {
          const char *r = strpbrk (p1, p2);

          if (r == NULL)
            return const0_rtx;

          /* Return an offset into the constant string argument.  */
          return expand_expr (fold (build (PLUS_EXPR, TREE_TYPE (s1),
                                           s1, ssize_int (r - p1))),
                              target, mode, EXPAND_NORMAL);
        }

      if (p2[0] == '\0')
        {
          /* strpbrk(x, "") == NULL.
             Evaluate and ignore the arguments in case they had
             side-effects.  */
          expand_expr (s1, const0_rtx, VOIDmode, EXPAND_NORMAL);
          return const0_rtx;
        }

      if (p2[1] != '\0')
        return 0;  /* Really call strpbrk.  */

      fn = implicit_built_in_decls[BUILT_IN_STRCHR];
      if (!fn)
        return 0;

      /* New argument list transforming strpbrk(s1, s2) to
         strchr(s1, s2[0]).  */
      arglist =
        build_tree_list (NULL_TREE, build_int_2 (p2[0], 0));
      arglist = tree_cons (NULL_TREE, s1, arglist);
      return expand_expr (build_function_call_expr (fn, arglist),
                          target, mode, EXPAND_NORMAL);
    }
}

/* Callback routine for store_by_pieces.  Read GET_MODE_BITSIZE (MODE)
   bytes from constant string DATA + OFFSET and return it as target
   constant.  */

static rtx
builtin_memcpy_read_str (void *data, HOST_WIDE_INT offset,
                         enum machine_mode mode)
{
  const char *str = (const char *) data;

  if (offset < 0
      || ((unsigned HOST_WIDE_INT) offset + GET_MODE_SIZE (mode)
          > strlen (str) + 1))
    abort ();  /* Attempt to read past the end of constant string.  */

  return c_readstr (str + offset, mode);
}

/* Expand a call to the memcpy builtin, with arguments in ARGLIST.
   Return 0 if we failed, the caller should emit a normal call,
   otherwise try to get the result in TARGET, if convenient (and in
   mode MODE if that's convenient).  */
static rtx
expand_builtin_memcpy (tree arglist, rtx target, enum machine_mode mode)
{
  if (!validate_arglist (arglist,
                         POINTER_TYPE, POINTER_TYPE, INTEGER_TYPE, VOID_TYPE))
    return 0;
  else
    {
      tree dest = TREE_VALUE (arglist);
      tree src = TREE_VALUE (TREE_CHAIN (arglist));
      tree len = TREE_VALUE (TREE_CHAIN (TREE_CHAIN (arglist)));
      const char *src_str;
      unsigned int src_align = get_pointer_alignment (src, BIGGEST_ALIGNMENT);
      unsigned int dest_align
        = get_pointer_alignment (dest, BIGGEST_ALIGNMENT);
      rtx dest_mem, src_mem, dest_addr, len_rtx;

      /* If DEST is not a pointer type, call the normal function.  */
      if (dest_align == 0)
        return 0;

      /* If the LEN parameter is zero, return DEST.  */
      if (host_integerp (len, 1) && tree_low_cst (len, 1) == 0)
        {
          /* Evaluate and ignore SRC in case it has side-effects.  */
          expand_expr (src, const0_rtx, VOIDmode, EXPAND_NORMAL);
          return expand_expr (dest, target, mode, EXPAND_NORMAL);
        }

      /* If either SRC is not a pointer type, don't do this
         operation in-line.  */
      if (src_align == 0)
        return 0;

      dest_mem = get_memory_rtx (dest);
      set_mem_align (dest_mem, dest_align);
      len_rtx = expand_expr (len, NULL_RTX, VOIDmode, 0);
      src_str = c_getstr (src);

      /* If SRC is a string constant and block move would be done
         by pieces, we can avoid loading the string from memory
         and only stored the computed constants.  */
      if (src_str
          && GET_CODE (len_rtx) == CONST_INT
          && (unsigned HOST_WIDE_INT) INTVAL (len_rtx) <= strlen (src_str) + 1
          && can_store_by_pieces (INTVAL (len_rtx), builtin_memcpy_read_str,
                                  (void *) src_str, dest_align))
        {
          dest_mem = store_by_pieces (dest_mem, INTVAL (len_rtx),
                                      builtin_memcpy_read_str,
                                      (void *) src_str, dest_align, 0);
          dest_mem = force_operand (XEXP (dest_mem, 0), NULL_RTX);
#ifdef POINTERS_EXTEND_UNSIGNED
          if (GET_MODE (dest_mem) != ptr_mode)
            dest_mem = convert_memory_address (ptr_mode, dest_mem);
#endif
          return dest_mem;
        }

      src_mem = get_memory_rtx (src);
      set_mem_align (src_mem, src_align);

      /* Copy word part most expediently.  */
      dest_addr = emit_block_move (dest_mem, src_mem, len_rtx,
                                   BLOCK_OP_NORMAL);

      if (dest_addr == 0)
        {
          dest_addr = force_operand (XEXP (dest_mem, 0), NULL_RTX);
#ifdef POINTERS_EXTEND_UNSIGNED
          if (GET_MODE (dest_addr) != ptr_mode)
            dest_addr = convert_memory_address (ptr_mode, dest_addr);
#endif
        }
      return dest_addr;
    }
}

/* Expand a call to the mempcpy builtin, with arguments in ARGLIST.
   Return 0 if we failed the caller should emit a normal call,
   otherwise try to get the result in TARGET, if convenient (and in
   mode MODE if that's convenient).  If ENDP is 0 return the
   destination pointer, if ENDP is 1 return the end pointer ala
   mempcpy, and if ENDP is 2 return the end pointer minus one ala
   stpcpy.  */

static rtx
expand_builtin_mempcpy (tree arglist, rtx target, enum machine_mode mode,
                        int endp)
{
  if (!validate_arglist (arglist,
                         POINTER_TYPE, POINTER_TYPE, INTEGER_TYPE, VOID_TYPE))
    return 0;
  /* If return value is ignored, transform mempcpy into memcpy.  */
  else if (target == const0_rtx)
    {
      tree fn = implicit_built_in_decls[BUILT_IN_MEMCPY];

      if (!fn)
        return 0;

      return expand_expr (build_function_call_expr (fn, arglist),
                          target, mode, EXPAND_NORMAL);
    }
  else
    {
      tree dest = TREE_VALUE (arglist);
      tree src = TREE_VALUE (TREE_CHAIN (arglist));
      tree len = TREE_VALUE (TREE_CHAIN (TREE_CHAIN (arglist)));
      const char *src_str;
      unsigned int src_align = get_pointer_alignment (src, BIGGEST_ALIGNMENT);
      unsigned int dest_align
        = get_pointer_alignment (dest, BIGGEST_ALIGNMENT);
      rtx dest_mem, src_mem, len_rtx;

      /* If DEST is not a pointer type or LEN is not constant,
         call the normal function.  */
      if (dest_align == 0 || !host_integerp (len, 1))
        return 0;

      /* If the LEN parameter is zero, return DEST.  */
      if (tree_low_cst (len, 1) == 0)
        {
          /* Evaluate and ignore SRC in case it has side-effects.  */
          expand_expr (src, const0_rtx, VOIDmode, EXPAND_NORMAL);
          return expand_expr (dest, target, mode, EXPAND_NORMAL);
        }

      /* If either SRC is not a pointer type, don't do this
         operation in-line.  */
      if (src_align == 0)
        return 0;

      len_rtx = expand_expr (len, NULL_RTX, VOIDmode, 0);
      src_str = c_getstr (src);

      /* If SRC is a string constant and block move would be done
         by pieces, we can avoid loading the string from memory
         and only stored the computed constants.  */
      if (src_str
          && GET_CODE (len_rtx) == CONST_INT
          && (unsigned HOST_WIDE_INT) INTVAL (len_rtx) <= strlen (src_str) + 1
          && can_store_by_pieces (INTVAL (len_rtx), builtin_memcpy_read_str,
                                  (void *) src_str, dest_align))
        {
          dest_mem = get_memory_rtx (dest);
          set_mem_align (dest_mem, dest_align);
          dest_mem = store_by_pieces (dest_mem, INTVAL (len_rtx),
                                      builtin_memcpy_read_str,
                                      (void *) src_str, dest_align, endp);
          dest_mem = force_operand (XEXP (dest_mem, 0), NULL_RTX);
#ifdef POINTERS_EXTEND_UNSIGNED
          if (GET_MODE (dest_mem) != ptr_mode)
            dest_mem = convert_memory_address (ptr_mode, dest_mem);
#endif
          return dest_mem;
        }

      if (GET_CODE (len_rtx) == CONST_INT
          && can_move_by_pieces (INTVAL (len_rtx),
                                 MIN (dest_align, src_align)))
        {
          dest_mem = get_memory_rtx (dest);
          set_mem_align (dest_mem, dest_align);
          src_mem = get_memory_rtx (src);
          set_mem_align (src_mem, src_align);
          dest_mem = move_by_pieces (dest_mem, src_mem, INTVAL (len_rtx),
                                     MIN (dest_align, src_align), endp);
          dest_mem = force_operand (XEXP (dest_mem, 0), NULL_RTX);
#ifdef POINTERS_EXTEND_UNSIGNED
          if (GET_MODE (dest_mem) != ptr_mode)
            dest_mem = convert_memory_address (ptr_mode, dest_mem);
#endif
          return dest_mem;
        }

      return 0;
    }
}

/* Expand expression EXP, which is a call to the memmove builtin.  Return 0
   if we failed the caller should emit a normal call.  */

static rtx
expand_builtin_memmove (tree arglist, rtx target, enum machine_mode mode)
{
  if (!validate_arglist (arglist,
                         POINTER_TYPE, POINTER_TYPE, INTEGER_TYPE, VOID_TYPE))
    return 0;
  else
    {
      tree dest = TREE_VALUE (arglist);
      tree src = TREE_VALUE (TREE_CHAIN (arglist));
      tree len = TREE_VALUE (TREE_CHAIN (TREE_CHAIN (arglist)));

      unsigned int src_align = get_pointer_alignment (src, BIGGEST_ALIGNMENT);
      unsigned int dest_align
        = get_pointer_alignment (dest, BIGGEST_ALIGNMENT);

      /* If DEST is not a pointer type, call the normal function.  */
      if (dest_align == 0)
        return 0;

      /* If the LEN parameter is zero, return DEST.  */
      if (host_integerp (len, 1) && tree_low_cst (len, 1) == 0)
        {
          /* Evaluate and ignore SRC in case it has side-effects.  */
          expand_expr (src, const0_rtx, VOIDmode, EXPAND_NORMAL);
          return expand_expr (dest, target, mode, EXPAND_NORMAL);
        }

      /* If either SRC is not a pointer type, don't do this
         operation in-line.  */
      if (src_align == 0)
        return 0;

      /* If src is categorized for a readonly section we can use
         normal memcpy.  */
      if (readonly_data_expr (src))
        {
          tree const fn = implicit_built_in_decls[BUILT_IN_MEMCPY];
          if (!fn)
            return 0;
          return expand_expr (build_function_call_expr (fn, arglist),
                              target, mode, EXPAND_NORMAL);
        }

      /* Otherwise, call the normal function.  */
      return 0;
   }
}

/* Expand expression EXP, which is a call to the bcopy builtin.  Return 0
   if we failed the caller should emit a normal call.  */

static rtx
expand_builtin_bcopy (tree arglist)
{
  tree src, dest, size, newarglist;

  if (!validate_arglist (arglist,
                         POINTER_TYPE, POINTER_TYPE, INTEGER_TYPE, VOID_TYPE))
    return NULL_RTX;

  src = TREE_VALUE (arglist);
  dest = TREE_VALUE (TREE_CHAIN (arglist));
  size = TREE_VALUE (TREE_CHAIN (TREE_CHAIN (arglist)));

  /* New argument list transforming bcopy(ptr x, ptr y, int z) to
     memmove(ptr y, ptr x, size_t z).   This is done this way
     so that if it isn't expanded inline, we fallback to
     calling bcopy instead of memmove.  */

  newarglist = build_tree_list (NULL_TREE, convert (sizetype, size));
  newarglist = tree_cons (NULL_TREE, src, newarglist);
  newarglist = tree_cons (NULL_TREE, dest, newarglist);

  return expand_builtin_memmove (newarglist, const0_rtx, VOIDmode);
}

/* Expand expression EXP, which is a call to the strcpy builtin.  Return 0
   if we failed the caller should emit a normal call, otherwise try to get
   the result in TARGET, if convenient (and in mode MODE if that's
   convenient).  */

static rtx
expand_builtin_strcpy (tree arglist, rtx target, enum machine_mode mode)
{
  tree fn, len, src, dst;

  if (!validate_arglist (arglist, POINTER_TYPE, POINTER_TYPE, VOID_TYPE))
    return 0;

  fn = implicit_built_in_decls[BUILT_IN_MEMCPY];
  if (!fn)
    return 0;

  src = TREE_VALUE (TREE_CHAIN (arglist));
  len = c_strlen (src, 1);
  if (len == 0 || TREE_SIDE_EFFECTS (len))
    return 0;

  dst = TREE_VALUE (arglist);
  len = size_binop (PLUS_EXPR, len, ssize_int (1));
  arglist = build_tree_list (NULL_TREE, len);
  arglist = tree_cons (NULL_TREE, src, arglist);
  arglist = tree_cons (NULL_TREE, dst, arglist);
  return expand_expr (build_function_call_expr (fn, arglist),
                      target, mode, EXPAND_NORMAL);
}

/* Expand a call to the stpcpy builtin, with arguments in ARGLIST.
   Return 0 if we failed the caller should emit a normal call,
   otherwise try to get the result in TARGET, if convenient (and in
   mode MODE if that's convenient).  */

static rtx
expand_builtin_stpcpy (tree arglist, rtx target, enum machine_mode mode)
{
  if (!validate_arglist (arglist, POINTER_TYPE, POINTER_TYPE, VOID_TYPE))
    return 0;
  else
    {
      tree dst, src, len;

      /* If return value is ignored, transform stpcpy into strcpy.  */
      if (target == const0_rtx)
        {
          tree fn = implicit_built_in_decls[BUILT_IN_STRCPY];
          if (!fn)
            return 0;

          return expand_expr (build_function_call_expr (fn, arglist),
                              target, mode, EXPAND_NORMAL);
        }

      /* Ensure we get an actual string whose length can be evaluated at
         compile-time, not an expression containing a string.  This is
         because the latter will potentially produce pessimized code
         when used to produce the return value.  */
      src = TREE_VALUE (TREE_CHAIN (arglist));
      if (! c_getstr (src) || ! (len = c_strlen (src, 0)))
        return 0;

      dst = TREE_VALUE (arglist);
      len = fold (size_binop (PLUS_EXPR, len, ssize_int (1)));
      arglist = build_tree_list (NULL_TREE, len);
      arglist = tree_cons (NULL_TREE, src, arglist);
      arglist = tree_cons (NULL_TREE, dst, arglist);
      return expand_builtin_mempcpy (arglist, target, mode, /*endp=*/2);
    }
}

/* Callback routine for store_by_pieces.  Read GET_MODE_BITSIZE (MODE)
   bytes from constant string DATA + OFFSET and return it as target
   constant.  */

static rtx
builtin_strncpy_read_str (void *data, HOST_WIDE_INT offset,
                          enum machine_mode mode)
{
  const char *str = (const char *) data;

  if ((unsigned HOST_WIDE_INT) offset > strlen (str))
    return const0_rtx;

  return c_readstr (str + offset, mode);
}

/* Expand expression EXP, which is a call to the strncpy builtin.  Return 0
   if we failed the caller should emit a normal call.  */

static rtx
expand_builtin_strncpy (tree arglist, rtx target, enum machine_mode mode)
{
  if (!validate_arglist (arglist,
                         POINTER_TYPE, POINTER_TYPE, INTEGER_TYPE, VOID_TYPE))
    return 0;
  else
    {
      tree slen = c_strlen (TREE_VALUE (TREE_CHAIN (arglist)), 1);
      tree len = TREE_VALUE (TREE_CHAIN (TREE_CHAIN (arglist)));
      tree fn;

      /* We must be passed a constant len parameter.  */
      if (TREE_CODE (len) != INTEGER_CST)
        return 0;

      /* If the len parameter is zero, return the dst parameter.  */
      if (integer_zerop (len))
        {
          /* Evaluate and ignore the src argument in case it has
             side-effects.  */
          expand_expr (TREE_VALUE (TREE_CHAIN (arglist)), const0_rtx,
                       VOIDmode, EXPAND_NORMAL);
          /* Return the dst parameter.  */
          return expand_expr (TREE_VALUE (arglist), target, mode,
                              EXPAND_NORMAL);
        }

      /* Now, we must be passed a constant src ptr parameter.  */
      if (slen == 0 || TREE_CODE (slen) != INTEGER_CST)
        return 0;

      slen = size_binop (PLUS_EXPR, slen, ssize_int (1));

      /* We're required to pad with trailing zeros if the requested
         len is greater than strlen(s2)+1.  In that case try to
         use store_by_pieces, if it fails, punt.  */
      if (tree_int_cst_lt (slen, len))
        {
          tree dest = TREE_VALUE (arglist);
          unsigned int dest_align
            = get_pointer_alignment (dest, BIGGEST_ALIGNMENT);
          const char *p = c_getstr (TREE_VALUE (TREE_CHAIN (arglist)));
          rtx dest_mem;

          if (!p || dest_align == 0 || !host_integerp (len, 1)
              || !can_store_by_pieces (tree_low_cst (len, 1),
                                       builtin_strncpy_read_str,
                                       (void *) p, dest_align))
            return 0;

          dest_mem = get_memory_rtx (dest);
          store_by_pieces (dest_mem, tree_low_cst (len, 1),
                           builtin_strncpy_read_str,
                           (void *) p, dest_align, 0);
          dest_mem = force_operand (XEXP (dest_mem, 0), NULL_RTX);
#ifdef POINTERS_EXTEND_UNSIGNED
          if (GET_MODE (dest_mem) != ptr_mode)
            dest_mem = convert_memory_address (ptr_mode, dest_mem);
#endif
          return dest_mem;
        }

      /* OK transform into builtin memcpy.  */
      fn = implicit_built_in_decls[BUILT_IN_MEMCPY];
      if (!fn)
        return 0;
      return expand_expr (build_function_call_expr (fn, arglist),
                          target, mode, EXPAND_NORMAL);
    }
}

/* Callback routine for store_by_pieces.  Read GET_MODE_BITSIZE (MODE)
   bytes from constant string DATA + OFFSET and return it as target
   constant.  */

static rtx
builtin_memset_read_str (void *data, HOST_WIDE_INT offset ATTRIBUTE_UNUSED,
                         enum machine_mode mode)
{
  const char *c = (const char *) data;
  char *p = alloca (GET_MODE_SIZE (mode));

  memset (p, *c, GET_MODE_SIZE (mode));

  return c_readstr (p, mode);
}

/* Callback routine for store_by_pieces.  Return the RTL of a register
   containing GET_MODE_SIZE (MODE) consecutive copies of the unsigned
   char value given in the RTL register data.  For example, if mode is
   4 bytes wide, return the RTL for 0x01010101*data.  */

static rtx
builtin_memset_gen_str (void *data, HOST_WIDE_INT offset ATTRIBUTE_UNUSED,
                        enum machine_mode mode)
{
  rtx target, coeff;
  size_t size;
  char *p;

  size = GET_MODE_SIZE (mode);
  if (size == 1)
    return (rtx) data;

  p = alloca (size);
  memset (p, 1, size);
  coeff = c_readstr (p, mode);

  target = convert_to_mode (mode, (rtx) data, 1);
  target = expand_mult (mode, target, coeff, NULL_RTX, 1);
  return force_reg (mode, target);
}

/* Expand expression EXP, which is a call to the memset builtin.  Return 0
   if we failed the caller should emit a normal call, otherwise try to get
   the result in TARGET, if convenient (and in mode MODE if that's
   convenient).  */

static rtx
expand_builtin_memset (tree arglist, rtx target, enum machine_mode mode)
{
  if (!validate_arglist (arglist,
                         POINTER_TYPE, INTEGER_TYPE, INTEGER_TYPE, VOID_TYPE))
    return 0;
  else
    {
      tree dest = TREE_VALUE (arglist);
      tree val = TREE_VALUE (TREE_CHAIN (arglist));
      tree len = TREE_VALUE (TREE_CHAIN (TREE_CHAIN (arglist)));
      char c;

      unsigned int dest_align
        = get_pointer_alignment (dest, BIGGEST_ALIGNMENT);
      rtx dest_mem, dest_addr, len_rtx;

      /* If DEST is not a pointer type, don't do this
         operation in-line.  */
      if (dest_align == 0)
        return 0;

      /* If the LEN parameter is zero, return DEST.  */
      if (host_integerp (len, 1) && tree_low_cst (len, 1) == 0)
        {
          /* Evaluate and ignore VAL in case it has side-effects.  */
          expand_expr (val, const0_rtx, VOIDmode, EXPAND_NORMAL);
          return expand_expr (dest, target, mode, EXPAND_NORMAL);
        }

      if (TREE_CODE (val) != INTEGER_CST)
        {
          rtx val_rtx;

          if (!host_integerp (len, 1))
            return 0;

          if (optimize_size && tree_low_cst (len, 1) > 1)
            return 0;

          /* Assume that we can memset by pieces if we can store the
           * the coefficients by pieces (in the required modes).
           * We can't pass builtin_memset_gen_str as that emits RTL.  */
          c = 1;
          if (!can_store_by_pieces (tree_low_cst (len, 1),
                                    builtin_memset_read_str,
                                    &c, dest_align))
            return 0;

          val = fold (build1 (CONVERT_EXPR, unsigned_char_type_node, val));
          val_rtx = expand_expr (val, NULL_RTX, VOIDmode, 0);
          val_rtx = force_reg (TYPE_MODE (unsigned_char_type_node),
                               val_rtx);
          dest_mem = get_memory_rtx (dest);
          store_by_pieces (dest_mem, tree_low_cst (len, 1),
                           builtin_memset_gen_str,
                           val_rtx, dest_align, 0);
          dest_mem = force_operand (XEXP (dest_mem, 0), NULL_RTX);
#ifdef POINTERS_EXTEND_UNSIGNED
          if (GET_MODE (dest_mem) != ptr_mode)
            dest_mem = convert_memory_address (ptr_mode, dest_mem);
#endif
          return dest_mem;
        }

      if (target_char_cast (val, &c))
        return 0;

      if (c)
        {
          if (!host_integerp (len, 1))
            return 0;
          if (!can_store_by_pieces (tree_low_cst (len, 1),
                                    builtin_memset_read_str, &c,
                                    dest_align))
            return 0;

          dest_mem = get_memory_rtx (dest);
          store_by_pieces (dest_mem, tree_low_cst (len, 1),
                           builtin_memset_read_str,
                           &c, dest_align, 0);
          dest_mem = force_operand (XEXP (dest_mem, 0), NULL_RTX);
#ifdef POINTERS_EXTEND_UNSIGNED
          if (GET_MODE (dest_mem) != ptr_mode)
            dest_mem = convert_memory_address (ptr_mode, dest_mem);
#endif
          return dest_mem;
        }

      len_rtx = expand_expr (len, NULL_RTX, VOIDmode, 0);

      dest_mem = get_memory_rtx (dest);
      set_mem_align (dest_mem, dest_align);
      dest_addr = clear_storage (dest_mem, len_rtx);

      if (dest_addr == 0)
        {
          dest_addr = force_operand (XEXP (dest_mem, 0), NULL_RTX);
#ifdef POINTERS_EXTEND_UNSIGNED
          if (GET_MODE (dest_addr) != ptr_mode)
            dest_addr = convert_memory_address (ptr_mode, dest_addr);
#endif
        }

      return dest_addr;
    }
}

/* Expand expression EXP, which is a call to the bzero builtin.  Return 0
   if we failed the caller should emit a normal call.  */

static rtx
expand_builtin_bzero (tree arglist)
{
  tree dest, size, newarglist;

  if (!validate_arglist (arglist, POINTER_TYPE, INTEGER_TYPE, VOID_TYPE))
    return NULL_RTX;

  dest = TREE_VALUE (arglist);
  size = TREE_VALUE (TREE_CHAIN (arglist));

  /* New argument list transforming bzero(ptr x, int y) to
     memset(ptr x, int 0, size_t y).   This is done this way
     so that if it isn't expanded inline, we fallback to
     calling bzero instead of memset.  */

  newarglist = build_tree_list (NULL_TREE, convert (sizetype, size));
  newarglist = tree_cons (NULL_TREE, integer_zero_node, newarglist);
  newarglist = tree_cons (NULL_TREE, dest, newarglist);

  return expand_builtin_memset (newarglist, const0_rtx, VOIDmode);
}

/* Expand expression EXP, which is a call to the memcmp built-in function.
   ARGLIST is the argument list for this call.  Return 0 if we failed and the
   caller should emit a normal call, otherwise try to get the result in
   TARGET, if convenient (and in mode MODE, if that's convenient).  */

static rtx
expand_builtin_memcmp (tree exp ATTRIBUTE_UNUSED, tree arglist, rtx target,
                       enum machine_mode mode)
{
  tree arg1, arg2, len;
  const char *p1, *p2;

  if (!validate_arglist (arglist,
                         POINTER_TYPE, POINTER_TYPE, INTEGER_TYPE, VOID_TYPE))
    return 0;

  arg1 = TREE_VALUE (arglist);
  arg2 = TREE_VALUE (TREE_CHAIN (arglist));
  len = TREE_VALUE (TREE_CHAIN (TREE_CHAIN (arglist)));

  /* If the len parameter is zero, return zero.  */
  if (host_integerp (len, 1) && tree_low_cst (len, 1) == 0)
    {
      /* Evaluate and ignore arg1 and arg2 in case they have
         side-effects.  */
      expand_expr (arg1, const0_rtx, VOIDmode, EXPAND_NORMAL);
      expand_expr (arg2, const0_rtx, VOIDmode, EXPAND_NORMAL);
      return const0_rtx;
    }

  p1 = c_getstr (arg1);
  p2 = c_getstr (arg2);

  /* If all arguments are constant, and the value of len is not greater
     than the lengths of arg1 and arg2, evaluate at compile-time.  */
  if (host_integerp (len, 1) && p1 && p2
      && compare_tree_int (len, strlen (p1) + 1) <= 0
      && compare_tree_int (len, strlen (p2) + 1) <= 0)
    {
      const int r = memcmp (p1, p2, tree_low_cst (len, 1));

      return (r < 0 ? constm1_rtx : (r > 0 ? const1_rtx : const0_rtx));
    }

  /* If len parameter is one, return an expression corresponding to
     (*(const unsigned char*)arg1 - (const unsigned char*)arg2).  */
  if (host_integerp (len, 1) && tree_low_cst (len, 1) == 1)
    {
      tree cst_uchar_node = build_type_variant (unsigned_char_type_node, 1, 0);
      tree cst_uchar_ptr_node = build_pointer_type (cst_uchar_node);
      tree ind1 =
      fold (build1 (CONVERT_EXPR, integer_type_node,
                    build1 (INDIRECT_REF, cst_uchar_node,
                            build1 (NOP_EXPR, cst_uchar_ptr_node, arg1))));
      tree ind2 =
      fold (build1 (CONVERT_EXPR, integer_type_node,
                    build1 (INDIRECT_REF, cst_uchar_node,
                            build1 (NOP_EXPR, cst_uchar_ptr_node, arg2))));
      tree result = fold (build (MINUS_EXPR, integer_type_node, ind1, ind2));
      return expand_expr (result, target, mode, EXPAND_NORMAL);
    }

#if defined HAVE_cmpmemsi || defined HAVE_cmpstrsi
  {
    rtx arg1_rtx, arg2_rtx, arg3_rtx;
    rtx result;
    rtx insn;

    int arg1_align
      = get_pointer_alignment (arg1, BIGGEST_ALIGNMENT) / BITS_PER_UNIT;
    int arg2_align
      = get_pointer_alignment (arg2, BIGGEST_ALIGNMENT) / BITS_PER_UNIT;
    enum machine_mode insn_mode;

#ifdef HAVE_cmpmemsi
    if (HAVE_cmpmemsi)
      insn_mode = insn_data[(int) CODE_FOR_cmpmemsi].operand[0].mode;
    else
#endif
#ifdef HAVE_cmpstrsi
    if (HAVE_cmpstrsi)
      insn_mode = insn_data[(int) CODE_FOR_cmpstrsi].operand[0].mode;
    else
#endif
      return 0;     

    /* If we don't have POINTER_TYPE, call the function.  */
    if (arg1_align == 0 || arg2_align == 0)
      return 0;

    /* Make a place to write the result of the instruction.  */
    result = target;
    if (! (result != 0
           && GET_CODE (result) == REG && GET_MODE (result) == insn_mode
           && REGNO (result) >= FIRST_PSEUDO_REGISTER))
      result = gen_reg_rtx (insn_mode);

    arg1_rtx = get_memory_rtx (arg1);
    arg2_rtx = get_memory_rtx (arg2);
    arg3_rtx = expand_expr (len, NULL_RTX, VOIDmode, 0);
#ifdef HAVE_cmpmemsi
    if (HAVE_cmpmemsi)
      insn = gen_cmpmemsi (result, arg1_rtx, arg2_rtx, arg3_rtx,
                           GEN_INT (MIN (arg1_align, arg2_align)));
    else
#endif
#ifdef HAVE_cmpstrsi
    if (HAVE_cmpstrsi)
      insn = gen_cmpstrsi (result, arg1_rtx, arg2_rtx, arg3_rtx,
                           GEN_INT (MIN (arg1_align, arg2_align)));
    else
#endif
      abort ();

    if (insn)
      emit_insn (insn);
    else
      emit_library_call_value (memcmp_libfunc, result, LCT_PURE_MAKE_BLOCK,
                               TYPE_MODE (integer_type_node), 3,
                               XEXP (arg1_rtx, 0), Pmode,
                               XEXP (arg2_rtx, 0), Pmode,
                               convert_to_mode (TYPE_MODE (sizetype), arg3_rtx,
                                                TREE_UNSIGNED (sizetype)),
                               TYPE_MODE (sizetype));

    /* Return the value in the proper mode for this function.  */
    mode = TYPE_MODE (TREE_TYPE (exp));
    if (GET_MODE (result) == mode)
      return result;
    else if (target != 0)
      {
        convert_move (target, result, 0);
        return target;
      }
    else
      return convert_to_mode (mode, result, 0);
  }
#endif

  return 0;
}

/* Expand expression EXP, which is a call to the strcmp builtin.  Return 0
   if we failed the caller should emit a normal call, otherwise try to get
   the result in TARGET, if convenient.  */

static rtx
expand_builtin_strcmp (tree exp, rtx target, enum machine_mode mode)
{
  tree arglist = TREE_OPERAND (exp, 1);
  tree arg1, arg2;
  const char *p1, *p2;

  if (!validate_arglist (arglist, POINTER_TYPE, POINTER_TYPE, VOID_TYPE))
    return 0;

  arg1 = TREE_VALUE (arglist);
  arg2 = TREE_VALUE (TREE_CHAIN (arglist));

  p1 = c_getstr (arg1);
  p2 = c_getstr (arg2);

  if (p1 && p2)
    {
      const int i = strcmp (p1, p2);
      return (i < 0 ? constm1_rtx : (i > 0 ? const1_rtx : const0_rtx));
    }

  /* If either arg is "", return an expression corresponding to
     (*(const unsigned char*)arg1 - (const unsigned char*)arg2).  */
  if ((p1 && *p1 == '\0') || (p2 && *p2 == '\0'))
    {
      tree cst_uchar_node = build_type_variant (unsigned_char_type_node, 1, 0);
      tree cst_uchar_ptr_node = build_pointer_type (cst_uchar_node);
      tree ind1 =
        fold (build1 (CONVERT_EXPR, integer_type_node,
                      build1 (INDIRECT_REF, cst_uchar_node,
                              build1 (NOP_EXPR, cst_uchar_ptr_node, arg1))));
      tree ind2 =
        fold (build1 (CONVERT_EXPR, integer_type_node,
                      build1 (INDIRECT_REF, cst_uchar_node,
                              build1 (NOP_EXPR, cst_uchar_ptr_node, arg2))));
      tree result = fold (build (MINUS_EXPR, integer_type_node, ind1, ind2));
      return expand_expr (result, target, mode, EXPAND_NORMAL);
    }

#ifdef HAVE_cmpstrsi
  if (HAVE_cmpstrsi)
  {
    tree len, len1, len2;
    rtx arg1_rtx, arg2_rtx, arg3_rtx;
    rtx result, insn;

    int arg1_align
      = get_pointer_alignment (arg1, BIGGEST_ALIGNMENT) / BITS_PER_UNIT;
    int arg2_align
      = get_pointer_alignment (arg2, BIGGEST_ALIGNMENT) / BITS_PER_UNIT;
    enum machine_mode insn_mode
      = insn_data[(int) CODE_FOR_cmpstrsi].operand[0].mode;

    len1 = c_strlen (arg1, 1);
    len2 = c_strlen (arg2, 1);

    if (len1)
      len1 = size_binop (PLUS_EXPR, ssize_int (1), len1);
    if (len2)
      len2 = size_binop (PLUS_EXPR, ssize_int (1), len2);

    /* If we don't have a constant length for the first, use the length
       of the second, if we know it.  We don't require a constant for
       this case; some cost analysis could be done if both are available
       but neither is constant.  For now, assume they're equally cheap,
       unless one has side effects.  If both strings have constant lengths,
       use the smaller.  */

    if (!len1)
      len = len2;
    else if (!len2)
      len = len1;
    else if (TREE_SIDE_EFFECTS (len1))
      len = len2;
    else if (TREE_SIDE_EFFECTS (len2))
      len = len1;
    else if (TREE_CODE (len1) != INTEGER_CST)
      len = len2;
    else if (TREE_CODE (len2) != INTEGER_CST)
      len = len1;
    else if (tree_int_cst_lt (len1, len2))
      len = len1;
    else
      len = len2;

    /* If both arguments have side effects, we cannot optimize.  */
    if (!len || TREE_SIDE_EFFECTS (len))
      return 0;

    /* If we don't have POINTER_TYPE, call the function.  */
    if (arg1_align == 0 || arg2_align == 0)
      return 0;

    /* Make a place to write the result of the instruction.  */
    result = target;
    if (! (result != 0
           && GET_CODE (result) == REG && GET_MODE (result) == insn_mode
           && REGNO (result) >= FIRST_PSEUDO_REGISTER))
      result = gen_reg_rtx (insn_mode);

    arg1_rtx = get_memory_rtx (arg1);
    arg2_rtx = get_memory_rtx (arg2);
    arg3_rtx = expand_expr (len, NULL_RTX, VOIDmode, 0);
    insn = gen_cmpstrsi (result, arg1_rtx, arg2_rtx, arg3_rtx,
                         GEN_INT (MIN (arg1_align, arg2_align)));
    if (!insn)
      return 0;

    emit_insn (insn);

    /* Return the value in the proper mode for this function.  */
    mode = TYPE_MODE (TREE_TYPE (exp));
    if (GET_MODE (result) == mode)
      return result;
    if (target == 0)
      return convert_to_mode (mode, result, 0);
    convert_move (target, result, 0);
    return target;
  }
#endif
  return 0;
}

/* Expand expression EXP, which is a call to the strncmp builtin.  Return 0
   if we failed the caller should emit a normal call, otherwise try to get
   the result in TARGET, if convenient.  */

static rtx
expand_builtin_strncmp (tree exp, rtx target, enum machine_mode mode)
{
  tree arglist = TREE_OPERAND (exp, 1);
  tree arg1, arg2, arg3;
  const char *p1, *p2;

  if (!validate_arglist (arglist,
                         POINTER_TYPE, POINTER_TYPE, INTEGER_TYPE, VOID_TYPE))
    return 0;

  arg1 = TREE_VALUE (arglist);
  arg2 = TREE_VALUE (TREE_CHAIN (arglist));
  arg3 = TREE_VALUE (TREE_CHAIN (TREE_CHAIN (arglist)));

  /* If the len parameter is zero, return zero.  */
  if (host_integerp (arg3, 1) && tree_low_cst (arg3, 1) == 0)
    {
      /* Evaluate and ignore arg1 and arg2 in case they have
         side-effects.  */
      expand_expr (arg1, const0_rtx, VOIDmode, EXPAND_NORMAL);
      expand_expr (arg2, const0_rtx, VOIDmode, EXPAND_NORMAL);
      return const0_rtx;
    }

  p1 = c_getstr (arg1);
  p2 = c_getstr (arg2);

  /* If all arguments are constant, evaluate at compile-time.  */
  if (host_integerp (arg3, 1) && p1 && p2)
    {
      const int r = strncmp (p1, p2, tree_low_cst (arg3, 1));
      return (r < 0 ? constm1_rtx : (r > 0 ? const1_rtx : const0_rtx));
    }

  /* If len == 1 or (either string parameter is "" and (len >= 1)),
      return (*(const u_char*)arg1 - *(const u_char*)arg2).  */
  if (host_integerp (arg3, 1)
      && (tree_low_cst (arg3, 1) == 1
          || (tree_low_cst (arg3, 1) > 1
              && ((p1 && *p1 == '\0') || (p2 && *p2 == '\0')))))
    {
      tree cst_uchar_node = build_type_variant (unsigned_char_type_node, 1, 0);
      tree cst_uchar_ptr_node = build_pointer_type (cst_uchar_node);
      tree ind1 =
        fold (build1 (CONVERT_EXPR, integer_type_node,
                      build1 (INDIRECT_REF, cst_uchar_node,
                              build1 (NOP_EXPR, cst_uchar_ptr_node, arg1))));
      tree ind2 =
        fold (build1 (CONVERT_EXPR, integer_type_node,
                      build1 (INDIRECT_REF, cst_uchar_node,
                              build1 (NOP_EXPR, cst_uchar_ptr_node, arg2))));
      tree result = fold (build (MINUS_EXPR, integer_type_node, ind1, ind2));
      return expand_expr (result, target, mode, EXPAND_NORMAL);
    }

  /* If c_strlen can determine an expression for one of the string
     lengths, and it doesn't have side effects, then emit cmpstrsi
     using length MIN(strlen(string)+1, arg3).  */
#ifdef HAVE_cmpstrsi
  if (HAVE_cmpstrsi)
  {
    tree len, len1, len2;
    rtx arg1_rtx, arg2_rtx, arg3_rtx;
    rtx result, insn;

    int arg1_align
      = get_pointer_alignment (arg1, BIGGEST_ALIGNMENT) / BITS_PER_UNIT;
    int arg2_align
      = get_pointer_alignment (arg2, BIGGEST_ALIGNMENT) / BITS_PER_UNIT;
    enum machine_mode insn_mode
      = insn_data[(int) CODE_FOR_cmpstrsi].operand[0].mode;

    len1 = c_strlen (arg1, 1);
    len2 = c_strlen (arg2, 1);

    if (len1)
      len1 = size_binop (PLUS_EXPR, ssize_int (1), len1);
    if (len2)
      len2 = size_binop (PLUS_EXPR, ssize_int (1), len2);

    /* If we don't have a constant length for the first, use the length
       of the second, if we know it.  We don't require a constant for
       this case; some cost analysis could be done if both are available
       but neither is constant.  For now, assume they're equally cheap,
       unless one has side effects.  If both strings have constant lengths,
       use the smaller.  */

    if (!len1)
      len = len2;
    else if (!len2)
      len = len1;
    else if (TREE_SIDE_EFFECTS (len1))
      len = len2;
    else if (TREE_SIDE_EFFECTS (len2))
      len = len1;
    else if (TREE_CODE (len1) != INTEGER_CST)
      len = len2;
    else if (TREE_CODE (len2) != INTEGER_CST)
      len = len1;
    else if (tree_int_cst_lt (len1, len2))
      len = len1;
    else
      len = len2;

    /* If both arguments have side effects, we cannot optimize.  */
    if (!len || TREE_SIDE_EFFECTS (len))
      return 0;

    /* The actual new length parameter is MIN(len,arg3).  */
    len = fold (build (MIN_EXPR, TREE_TYPE (len), len, arg3));

    /* If we don't have POINTER_TYPE, call the function.  */
    if (arg1_align == 0 || arg2_align == 0)
      return 0;

    /* Make a place to write the result of the instruction.  */
    result = target;
    if (! (result != 0
           && GET_CODE (result) == REG && GET_MODE (result) == insn_mode
           && REGNO (result) >= FIRST_PSEUDO_REGISTER))
      result = gen_reg_rtx (insn_mode);

    arg1_rtx = get_memory_rtx (arg1);
    arg2_rtx = get_memory_rtx (arg2);
    arg3_rtx = expand_expr (len, NULL_RTX, VOIDmode, 0);
    insn = gen_cmpstrsi (result, arg1_rtx, arg2_rtx, arg3_rtx,
                         GEN_INT (MIN (arg1_align, arg2_align)));
    if (!insn)
      return 0;

    emit_insn (insn);

    /* Return the value in the proper mode for this function.  */
    mode = TYPE_MODE (TREE_TYPE (exp));
    if (GET_MODE (result) == mode)
      return result;
    if (target == 0)
      return convert_to_mode (mode, result, 0);
    convert_move (target, result, 0);
    return target;
  }
#endif
  return 0;
}

/* Expand expression EXP, which is a call to the strcat builtin.
   Return 0 if we failed the caller should emit a normal call,
   otherwise try to get the result in TARGET, if convenient.  */

static rtx
expand_builtin_strcat (tree arglist, rtx target, enum machine_mode mode)
{
  if (!validate_arglist (arglist, POINTER_TYPE, POINTER_TYPE, VOID_TYPE))
    return 0;
  else
    {
      tree dst = TREE_VALUE (arglist),
        src = TREE_VALUE (TREE_CHAIN (arglist));
      const char *p = c_getstr (src);

      if (p)
        {
          /* If the string length is zero, return the dst parameter.  */
          if (*p == '\0')
            return expand_expr (dst, target, mode, EXPAND_NORMAL);
          else if (!optimize_size)
            {
              /* Otherwise if !optimize_size, see if we can store by
                 pieces into (dst + strlen(dst)).  */
              tree newdst, arglist,
                strlen_fn = implicit_built_in_decls[BUILT_IN_STRLEN];
              
              /* This is the length argument.  */
              arglist = build_tree_list (NULL_TREE,
                                         fold (size_binop (PLUS_EXPR,
                                                           c_strlen (src, 0),
                                                           ssize_int (1))));
              /* Prepend src argument.  */
              arglist = tree_cons (NULL_TREE, src, arglist);
              
              /* We're going to use dst more than once.  */
              dst = save_expr (dst);

              /* Create strlen (dst).  */
              newdst =
                fold (build_function_call_expr (strlen_fn,
                                                build_tree_list (NULL_TREE,
                                                                 dst)));
              /* Create (dst + strlen (dst)).  */
              newdst = fold (build (PLUS_EXPR, TREE_TYPE (dst), dst, newdst));

              /* Prepend the new dst argument.  */
              arglist = tree_cons (NULL_TREE, newdst, arglist);
              
              /* We don't want to get turned into a memcpy if the
                 target is const0_rtx, i.e. when the return value
                 isn't used.  That would produce pessimized code so
                 pass in a target of zero, it should never actually be
                 used.  If this was successful return the original
                 dst, not the result of mempcpy.  */
              if (expand_builtin_mempcpy (arglist, /*target=*/0, mode, /*endp=*/0))
                return expand_expr (dst, target, mode, EXPAND_NORMAL);
              else
                return 0;
            }
        }

      return 0;
    }
}

/* Expand expression EXP, which is a call to the strncat builtin.
   Return 0 if we failed the caller should emit a normal call,
   otherwise try to get the result in TARGET, if convenient.  */

static rtx
expand_builtin_strncat (tree arglist, rtx target, enum machine_mode mode)
{
  if (!validate_arglist (arglist,
                         POINTER_TYPE, POINTER_TYPE, INTEGER_TYPE, VOID_TYPE))
    return 0;
  else
    {
      tree dst = TREE_VALUE (arglist),
        src = TREE_VALUE (TREE_CHAIN (arglist)),
        len = TREE_VALUE (TREE_CHAIN (TREE_CHAIN (arglist)));
      const char *p = c_getstr (src);

      /* If the requested length is zero, or the src parameter string
          length is zero, return the dst parameter.  */
      if (integer_zerop (len) || (p && *p == '\0'))
        {
          /* Evaluate and ignore the src and len parameters in case
             they have side-effects.  */
          expand_expr (src, const0_rtx, VOIDmode, EXPAND_NORMAL);
          expand_expr (len, const0_rtx, VOIDmode, EXPAND_NORMAL);
          return expand_expr (dst, target, mode, EXPAND_NORMAL);
        }

      /* If the requested len is greater than or equal to the string
         length, call strcat.  */
      if (TREE_CODE (len) == INTEGER_CST && p
          && compare_tree_int (len, strlen (p)) >= 0)
        {
          tree newarglist
            = tree_cons (NULL_TREE, dst, build_tree_list (NULL_TREE, src));
          tree fn = implicit_built_in_decls[BUILT_IN_STRCAT];

          /* If the replacement _DECL isn't initialized, don't do the
             transformation.  */
          if (!fn)
            return 0;

          return expand_expr (build_function_call_expr (fn, newarglist),
                              target, mode, EXPAND_NORMAL);
        }
      return 0;
    }
}

/* Expand expression EXP, which is a call to the strspn builtin.
   Return 0 if we failed the caller should emit a normal call,
   otherwise try to get the result in TARGET, if convenient.  */

static rtx
expand_builtin_strspn (tree arglist, rtx target, enum machine_mode mode)
{
  if (!validate_arglist (arglist, POINTER_TYPE, POINTER_TYPE, VOID_TYPE))
    return 0;
  else
    {
      tree s1 = TREE_VALUE (arglist), s2 = TREE_VALUE (TREE_CHAIN (arglist));
      const char *p1 = c_getstr (s1), *p2 = c_getstr (s2);

      /* If both arguments are constants, evaluate at compile-time.  */
      if (p1 && p2)
        {
          const size_t r = strspn (p1, p2);
          return expand_expr (size_int (r), target, mode, EXPAND_NORMAL);
        }

      /* If either argument is "", return 0.  */
      if ((p1 && *p1 == '\0') || (p2 && *p2 == '\0'))
        {
          /* Evaluate and ignore both arguments in case either one has
             side-effects.  */
          expand_expr (s1, const0_rtx, VOIDmode, EXPAND_NORMAL);
          expand_expr (s2, const0_rtx, VOIDmode, EXPAND_NORMAL);
          return const0_rtx;
        }
      return 0;
    }
}

/* Expand expression EXP, which is a call to the strcspn builtin.
   Return 0 if we failed the caller should emit a normal call,
   otherwise try to get the result in TARGET, if convenient.  */

static rtx
expand_builtin_strcspn (tree arglist, rtx target, enum machine_mode mode)
{
  if (!validate_arglist (arglist, POINTER_TYPE, POINTER_TYPE, VOID_TYPE))
    return 0;
  else
    {
      tree s1 = TREE_VALUE (arglist), s2 = TREE_VALUE (TREE_CHAIN (arglist));
      const char *p1 = c_getstr (s1), *p2 = c_getstr (s2);

      /* If both arguments are constants, evaluate at compile-time.  */
      if (p1 && p2)
        {
          const size_t r = strcspn (p1, p2);
          return expand_expr (size_int (r), target, mode, EXPAND_NORMAL);
        }

      /* If the first argument is "", return 0.  */
      if (p1 && *p1 == '\0')
        {
          /* Evaluate and ignore argument s2 in case it has
             side-effects.  */
          expand_expr (s2, const0_rtx, VOIDmode, EXPAND_NORMAL);
          return const0_rtx;
        }

      /* If the second argument is "", return __builtin_strlen(s1).  */
      if (p2 && *p2 == '\0')
        {
          tree newarglist = build_tree_list (NULL_TREE, s1),
            fn = implicit_built_in_decls[BUILT_IN_STRLEN];

          /* If the replacement _DECL isn't initialized, don't do the
             transformation.  */
          if (!fn)
            return 0;

          return expand_expr (build_function_call_expr (fn, newarglist),
                              target, mode, EXPAND_NORMAL);
        }
      return 0;
    }
}

/* Expand a call to __builtin_saveregs, generating the result in TARGET,
   if that's convenient.  */

rtx
expand_builtin_saveregs (void)
{
  rtx val, seq;

  /* Don't do __builtin_saveregs more than once in a function.
     Save the result of the first call and reuse it.  */
  if (saveregs_value != 0)
    return saveregs_value;

  /* When this function is called, it means that registers must be
     saved on entry to this function.  So we migrate the call to the
     first insn of this function.  */

  start_sequence ();

#ifdef EXPAND_BUILTIN_SAVEREGS
  /* Do whatever the machine needs done in this case.  */
  val = EXPAND_BUILTIN_SAVEREGS ();
#else
  /* ??? We used to try and build up a call to the out of line function,
     guessing about what registers needed saving etc.  This became much
     harder with __builtin_va_start, since we don't have a tree for a
     call to __builtin_saveregs to fall back on.  There was exactly one
     port (i860) that used this code, and I'm unconvinced it could actually
     handle the general case.  So we no longer try to handle anything
     weird and make the backend absorb the evil.  */

  error ("__builtin_saveregs not supported by this target");
  val = const0_rtx;
#endif

  seq = get_insns ();
  end_sequence ();

  saveregs_value = val;

  /* Put the insns after the NOTE that starts the function.  If this
     is inside a start_sequence, make the outer-level insn chain current, so
     the code is placed at the start of the function.  */
  push_topmost_sequence ();
  emit_insn_after (seq, get_insns ());
  pop_topmost_sequence ();

  return val;
}

/* __builtin_args_info (N) returns word N of the arg space info
   for the current function.  The number and meanings of words
   is controlled by the definition of CUMULATIVE_ARGS.  */

static rtx
expand_builtin_args_info (tree arglist)
{
  int nwords = sizeof (CUMULATIVE_ARGS) / sizeof (int);
  int *word_ptr = (int *) &current_function_args_info;

  if (sizeof (CUMULATIVE_ARGS) % sizeof (int) != 0)
    abort ();

  if (arglist != 0)
    {
      if (!host_integerp (TREE_VALUE (arglist), 0))
        error ("argument of `__builtin_args_info' must be constant");
      else
        {
          HOST_WIDE_INT wordnum = tree_low_cst (TREE_VALUE (arglist), 0);

          if (wordnum < 0 || wordnum >= nwords)
            error ("argument of `__builtin_args_info' out of range");
          else
            return GEN_INT (word_ptr[wordnum]);
        }
    }
  else
    error ("missing argument in `__builtin_args_info'");

  return const0_rtx;
}

/* Expand ARGLIST, from a call to __builtin_next_arg.  */

static rtx
expand_builtin_next_arg (tree arglist)
{
  tree fntype = TREE_TYPE (current_function_decl);

  if (TYPE_ARG_TYPES (fntype) == 0
      || (TREE_VALUE (tree_last (TYPE_ARG_TYPES (fntype)))
          == void_type_node))
    {
      error ("`va_start' used in function with fixed args");
      return const0_rtx;
    }

  if (arglist)
    {
      tree last_parm = tree_last (DECL_ARGUMENTS (current_function_decl));
      tree arg = TREE_VALUE (arglist);

      /* Strip off all nops for the sake of the comparison.  This
         is not quite the same as STRIP_NOPS.  It does more.
         We must also strip off INDIRECT_EXPR for C++ reference
         parameters.  */
      while (TREE_CODE (arg) == NOP_EXPR
             || TREE_CODE (arg) == CONVERT_EXPR
             || TREE_CODE (arg) == NON_LVALUE_EXPR
             || TREE_CODE (arg) == INDIRECT_REF)
        arg = TREE_OPERAND (arg, 0);
      if (arg != last_parm)
        warning ("second parameter of `va_start' not last named argument");
    }
  else
    /* Evidently an out of date version of <stdarg.h>; can't validate
       va_start's second argument, but can still work as intended.  */
    warning ("`__builtin_next_arg' called without an argument");

  return expand_binop (Pmode, add_optab,
                       current_function_internal_arg_pointer,
                       current_function_arg_offset_rtx,
                       NULL_RTX, 0, OPTAB_LIB_WIDEN);
}

/* Make it easier for the backends by protecting the valist argument
   from multiple evaluations.  */

static tree
stabilize_va_list (tree valist, int needs_lvalue)
{
  if (TREE_CODE (va_list_type_node) == ARRAY_TYPE)
    {
      if (TREE_SIDE_EFFECTS (valist))
        valist = save_expr (valist);

      /* For this case, the backends will be expecting a pointer to
         TREE_TYPE (va_list_type_node), but it's possible we've
         actually been given an array (an actual va_list_type_node).
         So fix it.  */
      if (TREE_CODE (TREE_TYPE (valist)) == ARRAY_TYPE)
        {
          tree p1 = build_pointer_type (TREE_TYPE (va_list_type_node));
          tree p2 = build_pointer_type (va_list_type_node);

          valist = build1 (ADDR_EXPR, p2, valist);
          valist = fold (build1 (NOP_EXPR, p1, valist));
        }
    }
  else
    {
      tree pt;

      if (! needs_lvalue)
        {
          if (! TREE_SIDE_EFFECTS (valist))
            return valist;

          pt = build_pointer_type (va_list_type_node);
          valist = fold (build1 (ADDR_EXPR, pt, valist));
          TREE_SIDE_EFFECTS (valist) = 1;
        }

      if (TREE_SIDE_EFFECTS (valist))
        valist = save_expr (valist);
      valist = fold (build1 (INDIRECT_REF, TREE_TYPE (TREE_TYPE (valist)),
                             valist));
    }

  return valist;
}

/* The "standard" implementation of va_start: just assign `nextarg' to
   the variable.  */

void
std_expand_builtin_va_start (tree valist, rtx nextarg)
{
  tree t;

  t = build (MODIFY_EXPR, TREE_TYPE (valist), valist,
             make_tree (ptr_type_node, nextarg));
  TREE_SIDE_EFFECTS (t) = 1;

  expand_expr (t, const0_rtx, VOIDmode, EXPAND_NORMAL);
}

/* Expand ARGLIST, from a call to __builtin_va_start.  */

static rtx
expand_builtin_va_start (tree arglist)
{
  rtx nextarg;
  tree chain, valist;

  chain = TREE_CHAIN (arglist);

  if (TREE_CHAIN (chain))
    error ("too many arguments to function `va_start'");

  nextarg = expand_builtin_next_arg (chain);
  valist = stabilize_va_list (TREE_VALUE (arglist), 1);

#ifdef EXPAND_BUILTIN_VA_START
  EXPAND_BUILTIN_VA_START (valist, nextarg);
#else
  std_expand_builtin_va_start (valist, nextarg);
#endif

  return const0_rtx;
}

/* The "standard" implementation of va_arg: read the value from the
   current (padded) address and increment by the (padded) size.  */

rtx
std_expand_builtin_va_arg (tree valist, tree type)
{
  tree addr_tree, t, type_size = NULL;
  tree align, alignm1;
  tree rounded_size;
  rtx addr;

  /* Compute the rounded size of the type.  */
  align = size_int (PARM_BOUNDARY / BITS_PER_UNIT);
  alignm1 = size_int (PARM_BOUNDARY / BITS_PER_UNIT - 1);
  if (type == error_mark_node
      || (type_size = TYPE_SIZE_UNIT (TYPE_MAIN_VARIANT (type))) == NULL
      || TREE_OVERFLOW (type_size))
    rounded_size = size_zero_node;
  else
    rounded_size = fold (build (MULT_EXPR, sizetype,
                                fold (build (TRUNC_DIV_EXPR, sizetype,
                                             fold (build (PLUS_EXPR, sizetype,
                                                          type_size, alignm1)),
                                             align)),
                                align));

  /* Get AP.  */
  addr_tree = valist;
  if (PAD_VARARGS_DOWN && ! integer_zerop (rounded_size))
    {
      /* Small args are padded downward.  */
      addr_tree = fold (build (PLUS_EXPR, TREE_TYPE (addr_tree), addr_tree,
                               fold (build (COND_EXPR, sizetype,
                                            fold (build (GT_EXPR, sizetype,
                                                         rounded_size,
                                                         align)),
                                            size_zero_node,
                                            fold (build (MINUS_EXPR, sizetype,
                                                         rounded_size,
                                                         type_size))))));
    }

  addr = expand_expr (addr_tree, NULL_RTX, Pmode, EXPAND_NORMAL);
  addr = copy_to_reg (addr);

  /* Compute new value for AP.  */
  if (! integer_zerop (rounded_size))
    {
      t = build (MODIFY_EXPR, TREE_TYPE (valist), valist,
                 build (PLUS_EXPR, TREE_TYPE (valist), valist,
                        rounded_size));
      TREE_SIDE_EFFECTS (t) = 1;
      expand_expr (t, const0_rtx, VOIDmode, EXPAND_NORMAL);
    }

  return addr;
}

/* Expand __builtin_va_arg, which is not really a builtin function, but
   a very special sort of operator.  */

rtx
expand_builtin_va_arg (tree valist, tree type)
{
  rtx addr, result;
  tree promoted_type, want_va_type, have_va_type;

  /* Verify that valist is of the proper type.  */

  want_va_type = va_list_type_node;
  have_va_type = TREE_TYPE (valist);
  if (TREE_CODE (want_va_type) == ARRAY_TYPE)
    {
      /* If va_list is an array type, the argument may have decayed
         to a pointer type, e.g. by being passed to another function.
         In that case, unwrap both types so that we can compare the
         underlying records.  */
      if (TREE_CODE (have_va_type) == ARRAY_TYPE
          || TREE_CODE (have_va_type) == POINTER_TYPE)
        {
          want_va_type = TREE_TYPE (want_va_type);
          have_va_type = TREE_TYPE (have_va_type);
        }
    }
  if (TYPE_MAIN_VARIANT (want_va_type) != TYPE_MAIN_VARIANT (have_va_type))
    {
      error ("first argument to `va_arg' not of type `va_list'");
      addr = const0_rtx;
    }

  /* Generate a diagnostic for requesting data of a type that cannot
     be passed through `...' due to type promotion at the call site.  */
  else if ((promoted_type = (*lang_hooks.types.type_promotes_to) (type))
           != type)
    {
      const char *name = "<anonymous type>", *pname = 0;
      static bool gave_help;

      if (TYPE_NAME (type))
        {
          if (TREE_CODE (TYPE_NAME (type)) == IDENTIFIER_NODE)
            name = IDENTIFIER_POINTER (TYPE_NAME (type));
          else if (TREE_CODE (TYPE_NAME (type)) == TYPE_DECL
                   && DECL_NAME (TYPE_NAME (type)))
            name = IDENTIFIER_POINTER (DECL_NAME (TYPE_NAME (type)));
        }
      if (TYPE_NAME (promoted_type))
        {
          if (TREE_CODE (TYPE_NAME (promoted_type)) == IDENTIFIER_NODE)
            pname = IDENTIFIER_POINTER (TYPE_NAME (promoted_type));
          else if (TREE_CODE (TYPE_NAME (promoted_type)) == TYPE_DECL
                   && DECL_NAME (TYPE_NAME (promoted_type)))
            pname = IDENTIFIER_POINTER (DECL_NAME (TYPE_NAME (promoted_type)));
        }

      /* Unfortunately, this is merely undefined, rather than a constraint
         violation, so we cannot make this an error.  If this call is never
         executed, the program is still strictly conforming.  */
      warning ("`%s' is promoted to `%s' when passed through `...'",
               name, pname);
      if (! gave_help)
        {
          gave_help = true;
          warning ("(so you should pass `%s' not `%s' to `va_arg')",
                   pname, name);
        }

      /* We can, however, treat "undefined" any way we please.
         Call abort to encourage the user to fix the program.  */
      expand_builtin_trap ();

      /* This is dead code, but go ahead and finish so that the
         mode of the result comes out right.  */
      addr = const0_rtx;
    }
  else
    {
      /* Make it easier for the backends by protecting the valist argument
         from multiple evaluations.  */
      valist = stabilize_va_list (valist, 0);

#ifdef EXPAND_BUILTIN_VA_ARG
      addr = EXPAND_BUILTIN_VA_ARG (valist, type);
#else
      addr = std_expand_builtin_va_arg (valist, type);
#endif
    }

#ifdef POINTERS_EXTEND_UNSIGNED
  if (GET_MODE (addr) != Pmode)
    addr = convert_memory_address (Pmode, addr);
#endif

  result = gen_rtx_MEM (TYPE_MODE (type), addr);
  set_mem_alias_set (result, get_varargs_alias_set ());

  return result;
}

/* Expand ARGLIST, from a call to __builtin_va_end.  */

static rtx
expand_builtin_va_end (tree arglist)
{
  tree valist = TREE_VALUE (arglist);

#ifdef EXPAND_BUILTIN_VA_END
  valist = stabilize_va_list (valist, 0);
  EXPAND_BUILTIN_VA_END (arglist);
#else
  /* Evaluate for side effects, if needed.  I hate macros that don't
     do that.  */
  if (TREE_SIDE_EFFECTS (valist))
    expand_expr (valist, const0_rtx, VOIDmode, EXPAND_NORMAL);
#endif

  return const0_rtx;
}

/* Expand ARGLIST, from a call to __builtin_va_copy.  We do this as a
   builtin rather than just as an assignment in stdarg.h because of the
   nastiness of array-type va_list types.  */

static rtx
expand_builtin_va_copy (tree arglist)
{
  tree dst, src, t;

  dst = TREE_VALUE (arglist);
  src = TREE_VALUE (TREE_CHAIN (arglist));

  dst = stabilize_va_list (dst, 1);
  src = stabilize_va_list (src, 0);

  if (TREE_CODE (va_list_type_node) != ARRAY_TYPE)
    {
      t = build (MODIFY_EXPR, va_list_type_node, dst, src);
      TREE_SIDE_EFFECTS (t) = 1;
      expand_expr (t, const0_rtx, VOIDmode, EXPAND_NORMAL);
    }
  else
    {
      rtx dstb, srcb, size;

      /* Evaluate to pointers.  */
      dstb = expand_expr (dst, NULL_RTX, Pmode, EXPAND_NORMAL);
      srcb = expand_expr (src, NULL_RTX, Pmode, EXPAND_NORMAL);
      size = expand_expr (TYPE_SIZE_UNIT (va_list_type_node), NULL_RTX,
                          VOIDmode, EXPAND_NORMAL);

#ifdef POINTERS_EXTEND_UNSIGNED
      if (GET_MODE (dstb) != Pmode)
        dstb = convert_memory_address (Pmode, dstb);

      if (GET_MODE (srcb) != Pmode)
        srcb = convert_memory_address (Pmode, srcb);
#endif

      /* "Dereference" to BLKmode memories.  */
      dstb = gen_rtx_MEM (BLKmode, dstb);
      set_mem_alias_set (dstb, get_alias_set (TREE_TYPE (TREE_TYPE (dst))));
      set_mem_align (dstb, TYPE_ALIGN (va_list_type_node));
      srcb = gen_rtx_MEM (BLKmode, srcb);
      set_mem_alias_set (srcb, get_alias_set (TREE_TYPE (TREE_TYPE (src))));
      set_mem_align (srcb, TYPE_ALIGN (va_list_type_node));

      /* Copy.  */
      emit_block_move (dstb, srcb, size, BLOCK_OP_NORMAL);
    }

  return const0_rtx;
}

/* Expand a call to one of the builtin functions __builtin_frame_address or
   __builtin_return_address.  */

static rtx
expand_builtin_frame_address (tree fndecl, tree arglist)
{
  /* The argument must be a nonnegative integer constant.
     It counts the number of frames to scan up the stack.
     The value is the return address saved in that frame.  */
  if (arglist == 0)
    /* Warning about missing arg was already issued.  */
    return const0_rtx;
  else if (! host_integerp (TREE_VALUE (arglist), 1))
    {
      if (DECL_FUNCTION_CODE (fndecl) == BUILT_IN_FRAME_ADDRESS)
        error ("invalid arg to `__builtin_frame_address'");
      else
        error ("invalid arg to `__builtin_return_address'");
      return const0_rtx;
    }
  else
    {
      rtx tem
        = expand_builtin_return_addr (DECL_FUNCTION_CODE (fndecl),
                                      tree_low_cst (TREE_VALUE (arglist), 1),
                                      hard_frame_pointer_rtx);

      /* Some ports cannot access arbitrary stack frames.  */
      if (tem == NULL)
        {
          if (DECL_FUNCTION_CODE (fndecl) == BUILT_IN_FRAME_ADDRESS)
            warning ("unsupported arg to `__builtin_frame_address'");
          else
            warning ("unsupported arg to `__builtin_return_address'");
          return const0_rtx;
        }

      /* For __builtin_frame_address, return what we've got.  */
      if (DECL_FUNCTION_CODE (fndecl) == BUILT_IN_FRAME_ADDRESS)
        return tem;

      if (GET_CODE (tem) != REG
          && ! CONSTANT_P (tem))
        tem = copy_to_mode_reg (Pmode, tem);
      return tem;
    }
}

/* Expand a call to the alloca builtin, with arguments ARGLIST.  Return 0 if
   we failed and the caller should emit a normal call, otherwise try to get
   the result in TARGET, if convenient.  */

static rtx
expand_builtin_alloca (tree arglist, rtx target)
{
  rtx op0;
  rtx result;

  if (!validate_arglist (arglist, INTEGER_TYPE, VOID_TYPE))
    return 0;

  /* Compute the argument.  */
  op0 = expand_expr (TREE_VALUE (arglist), NULL_RTX, VOIDmode, 0);

  /* Allocate the desired space.  */
  result = allocate_dynamic_stack_space (op0, target, BITS_PER_UNIT);

#ifdef POINTERS_EXTEND_UNSIGNED
  if (GET_MODE (result) != ptr_mode)
    result = convert_memory_address (ptr_mode, result);
#endif

  return result;
}

/* Expand a call to a unary builtin.  The arguments are in ARGLIST.
   Return 0 if a normal call should be emitted rather than expanding the
   function in-line.  If convenient, the result should be placed in TARGET.
   SUBTARGET may be used as the target for computing one of EXP's operands.  */

static rtx
expand_builtin_unop (enum machine_mode target_mode, tree arglist, rtx target,
                     rtx subtarget, optab op_optab)
{
  rtx op0;
  if (!validate_arglist (arglist, INTEGER_TYPE, VOID_TYPE))
    return 0;

  /* Compute the argument.  */
  op0 = expand_expr (TREE_VALUE (arglist), subtarget, VOIDmode, 0);
  /* Compute op, into TARGET if possible.
     Set TARGET to wherever the result comes back.  */
  target = expand_unop (TYPE_MODE (TREE_TYPE (TREE_VALUE (arglist))),
                        op_optab, op0, target, 1);
  if (target == 0)
    abort ();

  return convert_to_mode (target_mode, target, 0);
}

/* If the string passed to fputs is a constant and is one character
   long, we attempt to transform this call into __builtin_fputc().  */

static rtx
expand_builtin_fputs (tree arglist, rtx target, bool unlocked)
{
  tree len, fn;
  tree fn_fputc = unlocked ? implicit_built_in_decls[BUILT_IN_FPUTC_UNLOCKED]
    : implicit_built_in_decls[BUILT_IN_FPUTC];
  tree fn_fwrite = unlocked ? implicit_built_in_decls[BUILT_IN_FWRITE_UNLOCKED]
    : implicit_built_in_decls[BUILT_IN_FWRITE];

  /* If the return value is used, or the replacement _DECL isn't
     initialized, don't do the transformation.  */
  if (target != const0_rtx || !fn_fputc || !fn_fwrite)
    return 0;

  /* Verify the arguments in the original call.  */
  if (!validate_arglist (arglist, POINTER_TYPE, POINTER_TYPE, VOID_TYPE))
    return 0;

  /* Get the length of the string passed to fputs.  If the length
     can't be determined, punt.  */
  if (!(len = c_strlen (TREE_VALUE (arglist), 1))
      || TREE_CODE (len) != INTEGER_CST)
    return 0;

  switch (compare_tree_int (len, 1))
    {
    case -1: /* length is 0, delete the call entirely .  */
      {
        /* Evaluate and ignore the argument in case it has
           side-effects.  */
        expand_expr (TREE_VALUE (TREE_CHAIN (arglist)), const0_rtx,
                     VOIDmode, EXPAND_NORMAL);
        return const0_rtx;
      }
    case 0: /* length is 1, call fputc.  */
      {
        const char *p = c_getstr (TREE_VALUE (arglist));

        if (p != NULL)
          {
            /* New argument list transforming fputs(string, stream) to
               fputc(string[0], stream).  */
            arglist =
              build_tree_list (NULL_TREE, TREE_VALUE (TREE_CHAIN (arglist)));
            arglist =
              tree_cons (NULL_TREE, build_int_2 (p[0], 0), arglist);
            fn = fn_fputc;
            break;
          }
      }
      /* FALLTHROUGH */
    case 1: /* length is greater than 1, call fwrite.  */
      {
        tree string_arg;

        /* If optimizing for size keep fputs.  */
        if (optimize_size)
          return 0;
        string_arg = TREE_VALUE (arglist);
        /* New argument list transforming fputs(string, stream) to
           fwrite(string, 1, len, stream).  */
        arglist = build_tree_list (NULL_TREE, TREE_VALUE (TREE_CHAIN (arglist)));
        arglist = tree_cons (NULL_TREE, len, arglist);
        arglist = tree_cons (NULL_TREE, size_one_node, arglist);
        arglist = tree_cons (NULL_TREE, string_arg, arglist);
        fn = fn_fwrite;
        break;
      }
    default:
      abort ();
    }

  return expand_expr (build_function_call_expr (fn, arglist),
                      const0_rtx, VOIDmode, EXPAND_NORMAL);
}

/* Expand a call to __builtin_expect.  We return our argument and emit a
   NOTE_INSN_EXPECTED_VALUE note.  This is the expansion of __builtin_expect in
   a non-jump context.  */

static rtx
expand_builtin_expect (tree arglist, rtx target)
{
  tree exp, c;
  rtx note, rtx_c;

  if (arglist == NULL_TREE
      || TREE_CHAIN (arglist) == NULL_TREE)
    return const0_rtx;
  exp = TREE_VALUE (arglist);
  c = TREE_VALUE (TREE_CHAIN (arglist));

  if (TREE_CODE (c) != INTEGER_CST)
    {
      error ("second arg to `__builtin_expect' must be a constant");
      c = integer_zero_node;
    }

  target = expand_expr (exp, target, VOIDmode, EXPAND_NORMAL);

  /* Don't bother with expected value notes for integral constants.  */
  if (flag_guess_branch_prob && GET_CODE (target) != CONST_INT)
    {
      /* We do need to force this into a register so that we can be
         moderately sure to be able to correctly interpret the branch
         condition later.  */
      target = force_reg (GET_MODE (target), target);

      rtx_c = expand_expr (c, NULL_RTX, GET_MODE (target), EXPAND_NORMAL);

      note = emit_note (NOTE_INSN_EXPECTED_VALUE);
      NOTE_EXPECTED_VALUE (note) = gen_rtx_EQ (VOIDmode, target, rtx_c);
    }

  return target;
}

/* Like expand_builtin_expect, except do this in a jump context.  This is
   called from do_jump if the conditional is a __builtin_expect.  Return either
   a list of insns to emit the jump or NULL if we cannot optimize
   __builtin_expect.  We need to optimize this at jump time so that machines
   like the PowerPC don't turn the test into a SCC operation, and then jump
   based on the test being 0/1.  */

rtx
expand_builtin_expect_jump (tree exp, rtx if_false_label, rtx if_true_label)
{
  tree arglist = TREE_OPERAND (exp, 1);
  tree arg0 = TREE_VALUE (arglist);
  tree arg1 = TREE_VALUE (TREE_CHAIN (arglist));
  rtx ret = NULL_RTX;

  /* Only handle __builtin_expect (test, 0) and
     __builtin_expect (test, 1).  */
  if (TREE_CODE (TREE_TYPE (arg1)) == INTEGER_TYPE
      && (integer_zerop (arg1) || integer_onep (arg1)))
    {
      int num_jumps = 0;
      rtx insn;

      /* If we fail to locate an appropriate conditional jump, we'll
         fall back to normal evaluation.  Ensure that the expression
         can be re-evaluated.  */
      switch (unsafe_for_reeval (arg0))
        {
        case 0: /* Safe.  */
          break;

        case 1: /* Mildly unsafe.  */
          arg0 = unsave_expr (arg0);
          break;

        case 2: /* Wildly unsafe.  */
          return NULL_RTX;
        }

      /* Expand the jump insns.  */
      start_sequence ();
      do_jump (arg0, if_false_label, if_true_label);
      ret = get_insns ();
      end_sequence ();

      /* Now that the __builtin_expect has been validated, go through and add
         the expect's to each of the conditional jumps.  If we run into an
         error, just give up and generate the 'safe' code of doing a SCC
         operation and then doing a branch on that.  */
      insn = ret;
      while (insn != NULL_RTX)
        {
          rtx next = NEXT_INSN (insn);

          if (GET_CODE (insn) == JUMP_INSN && any_condjump_p (insn))
            {
              rtx ifelse = SET_SRC (pc_set (insn));
              rtx label;
              int taken;

              if (GET_CODE (XEXP (ifelse, 1)) == LABEL_REF)
                {
                  taken = 1;
                  label = XEXP (XEXP (ifelse, 1), 0);
                }
              /* An inverted jump reverses the probabilities.  */
              else if (GET_CODE (XEXP (ifelse, 2)) == LABEL_REF)
                {
                  taken = 0;
                  label = XEXP (XEXP (ifelse, 2), 0);
                }
              /* We shouldn't have to worry about conditional returns during
                 the expansion stage, but handle it gracefully anyway.  */
              else if (GET_CODE (XEXP (ifelse, 1)) == RETURN)
                {
                  taken = 1;
                  label = NULL_RTX;
                }
              /* An inverted return reverses the probabilities.  */
              else if (GET_CODE (XEXP (ifelse, 2)) == RETURN)
                {
                  taken = 0;
                  label = NULL_RTX;
                }
              else
                goto do_next_insn;

              /* If the test is expected to fail, reverse the
                 probabilities.  */
              if (integer_zerop (arg1))
                taken = 1 - taken;

              /* If we are jumping to the false label, reverse the
                 probabilities.  */
              if (label == NULL_RTX)
                ;               /* conditional return */
              else if (label == if_false_label)
                taken = 1 - taken;
              else if (label != if_true_label)
                goto do_next_insn;

              num_jumps++;
              predict_insn_def (insn, PRED_BUILTIN_EXPECT, taken);
            }

        do_next_insn:
          insn = next;
        }

      /* If no jumps were modified, fail and do __builtin_expect the normal
         way.  */
      if (num_jumps == 0)
        ret = NULL_RTX;
    }

  return ret;
}

void
expand_builtin_trap (void)
{
#ifdef HAVE_trap
  if (HAVE_trap)
    emit_insn (gen_trap ());
  else
#endif
    emit_library_call (abort_libfunc, LCT_NORETURN, VOIDmode, 0);
  emit_barrier ();
}

/* Expand a call to fabs, fabsf or fabsl with arguments ARGLIST.
   Return 0 if a normal call should be emitted rather than expanding
   the function inline.  If convenient, the result should be placed
   in TARGET.  SUBTARGET may be used as the target for computing
   the operand.  */

static rtx
expand_builtin_fabs (tree arglist, rtx target, rtx subtarget)
{
  enum machine_mode mode;
  tree arg;
  rtx op0;

  if (!validate_arglist (arglist, REAL_TYPE, VOID_TYPE))
    return 0;

  arg = TREE_VALUE (arglist);
  mode = TYPE_MODE (TREE_TYPE (arg));
  op0 = expand_expr (arg, subtarget, VOIDmode, 0);
  return expand_abs (mode, op0, target, 0, safe_from_p (target, arg, 1));
}

/* Expand a call to cabs, cabsf or cabsl with arguments ARGLIST.
   Return 0 if a normal call should be emitted rather than expanding
   the function inline.  If convenient, the result should be placed
   in target.  */

static rtx
expand_builtin_cabs (tree arglist, rtx target)
{
  enum machine_mode mode;
  tree arg;
  rtx op0;

  if (arglist == 0 || TREE_CHAIN (arglist))
    return 0;
  arg = TREE_VALUE (arglist);
  if (TREE_CODE (TREE_TYPE (arg)) != COMPLEX_TYPE
      || TREE_CODE (TREE_TYPE (TREE_TYPE (arg))) != REAL_TYPE)
    return 0;

  mode = TYPE_MODE (TREE_TYPE (arg));
  op0 = expand_expr (arg, NULL_RTX, VOIDmode, 0);
  return expand_complex_abs (mode, op0, target, 0);
}

/* Create a new constant string literal and return a char* pointer to it.
   The STRING_CST value is the LEN characters at STR.  */
static tree
build_string_literal (int len, const char *str)
{
  tree t, elem, index, type;

  t = build_string (len, str);
  elem = build_type_variant (char_type_node, 1, 0);
  index = build_index_type (build_int_2 (len - 1, 0));
  type = build_array_type (elem, index);
  TREE_TYPE (t) = type;
  TREE_CONSTANT (t) = 1;
  TREE_READONLY (t) = 1;
  TREE_STATIC (t) = 1;

  type = build_pointer_type (type);
  t = build1 (ADDR_EXPR, type, t);

  type = build_pointer_type (elem);
  t = build1 (NOP_EXPR, type, t);
  return t;
}

/* Expand a call to printf or printf_unlocked with argument list ARGLIST.
   Return 0 if a normal call should be emitted rather than transforming
   the function inline.  If convenient, the result should be placed in
   TARGET with mode MODE.  UNLOCKED indicates this is a printf_unlocked 
   call.  */
static rtx
expand_builtin_printf (tree arglist, rtx target, enum machine_mode mode,
                       bool unlocked)
{
  tree fn_putchar = unlocked
                    ? implicit_built_in_decls[BUILT_IN_PUTCHAR_UNLOCKED]
                    : implicit_built_in_decls[BUILT_IN_PUTCHAR];
  tree fn_puts = unlocked ? implicit_built_in_decls[BUILT_IN_PUTS_UNLOCKED]
                          : implicit_built_in_decls[BUILT_IN_PUTS];
  const char *fmt_str;
  tree fn, fmt, arg;

  /* If the return value is used, don't do the transformation.  */
  if (target != const0_rtx)
    return 0;

  /* Verify the required arguments in the original call.  */
  if (! arglist)
    return 0;
  fmt = TREE_VALUE (arglist);
  if (TREE_CODE (TREE_TYPE (fmt)) != POINTER_TYPE)
    return 0;
  arglist = TREE_CHAIN (arglist);

  /* Check whether the format is a literal string constant.  */
  fmt_str = c_getstr (fmt);
  if (fmt_str == NULL)
    return 0;

  /* If the format specifier was "%s\n", call __builtin_puts(arg).  */
  if (strcmp (fmt_str, "%s\n") == 0)
    {
      if (! arglist
          || TREE_CODE (TREE_TYPE (TREE_VALUE (arglist))) != POINTER_TYPE
          || TREE_CHAIN (arglist))
        return 0;
      fn = fn_puts;
    }
  /* If the format specifier was "%c", call __builtin_putchar(arg).  */
  else if (strcmp (fmt_str, "%c") == 0)
    {
      if (! arglist
          || TREE_CODE (TREE_TYPE (TREE_VALUE (arglist))) != INTEGER_TYPE
          || TREE_CHAIN (arglist))
        return 0;
      fn = fn_putchar;
    }
  else
    {
      /* We can't handle anything else with % args or %% ... yet.  */
      if (strchr (fmt_str, '%'))
        return 0;

      if (arglist)
        return 0;

      /* If the format specifier was "", printf does nothing.  */
      if (fmt_str[0] == '\0')
        return const0_rtx;
      /* If the format specifier has length of 1, call putchar.  */
      if (fmt_str[1] == '\0')
        {
          /* Given printf("c"), (where c is any one character,)
             convert "c"[0] to an int and pass that to the replacement
             function.  */
          arg = build_int_2 (fmt_str[0], 0);
          arglist = build_tree_list (NULL_TREE, arg);
          fn = fn_putchar;
        }
      else
        {
          /* If the format specifier was "string\n", call puts("string").  */
          size_t len = strlen (fmt_str);
          if (fmt_str[len - 1] == '\n')
            {
              /* Create a NUL-terminalted string that's one char shorter
                 than the original, stripping off the trailing '\n'.  */
              char *newstr = (char *) alloca (len);
              memcpy (newstr, fmt_str, len - 1);
              newstr[len - 1] = 0;

              arg = build_string_literal (len, newstr);
              arglist = build_tree_list (NULL_TREE, arg);
              fn = fn_puts;
            }
          else
            /* We'd like to arrange to call fputs(string,stdout) here,
               but we need stdout and don't have a way to get it yet.  */
            return 0;
        }
    }

  if (!fn)
    return 0;
  return expand_expr (build_function_call_expr (fn, arglist),
                      target, mode, EXPAND_NORMAL);
}

/* Expand a call to fprintf or fprintf_unlocked with argument list ARGLIST.
   Return 0 if a normal call should be emitted rather than transforming
   the function inline.  If convenient, the result should be placed in
   TARGET with mode MODE.  UNLOCKED indicates this is a fprintf_unlocked 
   call.  */
static rtx
expand_builtin_fprintf (tree arglist, rtx target, enum machine_mode mode,
                        bool unlocked)
{
  tree fn_fputc = unlocked ? implicit_built_in_decls[BUILT_IN_FPUTC_UNLOCKED]
                           : implicit_built_in_decls[BUILT_IN_FPUTC];
  tree fn_fputs = unlocked ? implicit_built_in_decls[BUILT_IN_FPUTS_UNLOCKED]
                           : implicit_built_in_decls[BUILT_IN_FPUTS];
  const char *fmt_str;
  tree fn, fmt, fp, arg;

  /* If the return value is used, don't do the transformation.  */
  if (target != const0_rtx)
    return 0;

  /* Verify the required arguments in the original call.  */
  if (! arglist)
    return 0;
  fp = TREE_VALUE (arglist);
  if (TREE_CODE (TREE_TYPE (fp)) != POINTER_TYPE)
    return 0;
  arglist = TREE_CHAIN (arglist);
  if (! arglist)
    return 0;
  fmt = TREE_VALUE (arglist);
  if (TREE_CODE (TREE_TYPE (fmt)) != POINTER_TYPE)
    return 0;
  arglist = TREE_CHAIN (arglist);

  /* Check whether the format is a literal string constant.  */
  fmt_str = c_getstr (fmt);
  if (fmt_str == NULL)
    return 0;

  /* If the format specifier was "%s", call __builtin_fputs(arg,fp).  */
  if (strcmp (fmt_str, "%s") == 0)
    {
      if (! arglist
          || TREE_CODE (TREE_TYPE (TREE_VALUE (arglist))) != POINTER_TYPE
          || TREE_CHAIN (arglist))
        return 0;
      arg = TREE_VALUE (arglist);
      arglist = build_tree_list (NULL_TREE, fp);
      arglist = tree_cons (NULL_TREE, arg, arglist);
      fn = fn_fputs;
    }
  /* If the format specifier was "%c", call __builtin_fputc(arg,fp).  */
  else if (strcmp (fmt_str, "%c") == 0)
    {
      if (! arglist
          || TREE_CODE (TREE_TYPE (TREE_VALUE (arglist))) != INTEGER_TYPE
          || TREE_CHAIN (arglist))
        return 0;
      arg = TREE_VALUE (arglist);
      arglist = build_tree_list (NULL_TREE, fp);
      arglist = tree_cons (NULL_TREE, arg, arglist);
      fn = fn_fputc;
    }
  else
    {
      /* We can't handle anything else with % args or %% ... yet.  */
      if (strchr (fmt_str, '%'))
        return 0;

      if (arglist)
        return 0;

      /* If the format specifier was "", fprintf does nothing.  */
      if (fmt_str[0] == '\0')
        {
          /* Evaluate and ignore FILE* argument for side-effects.  */
          expand_expr (fp, const0_rtx, VOIDmode, EXPAND_NORMAL);
          return const0_rtx;
        }

      /* When "string" doesn't contain %, replace all cases of
         fprintf(stream,string) with fputs(string,stream).  The fputs
         builtin will take care of special cases like length == 1.  */
      arglist = build_tree_list (NULL_TREE, fp);
      arglist = tree_cons (NULL_TREE, fmt, arglist);
      fn = fn_fputs;
    }

  if (!fn)
    return 0;
  return expand_expr (build_function_call_expr (fn, arglist),
                      target, mode, EXPAND_NORMAL);
}

/* Expand a call to sprintf with argument list ARGLIST.  Return 0 if
   a normal call should be emitted rather than expanding the function
   inline.  If convenient, the result should be placed in TARGET with
   mode MODE.  */

static rtx
expand_builtin_sprintf (tree arglist, rtx target, enum machine_mode mode)
{
  tree orig_arglist, dest, fmt;
  const char *fmt_str;

  orig_arglist = arglist;

  /* Verify the required arguments in the original call.  */
  if (! arglist)
    return 0;
  dest = TREE_VALUE (arglist);
  if (TREE_CODE (TREE_TYPE (dest)) != POINTER_TYPE)
    return 0;
  arglist = TREE_CHAIN (arglist);
  if (! arglist)
    return 0;
  fmt = TREE_VALUE (arglist);
  if (TREE_CODE (TREE_TYPE (fmt)) != POINTER_TYPE)
    return 0;
  arglist = TREE_CHAIN (arglist);

  /* Check whether the format is a literal string constant.  */
  fmt_str = c_getstr (fmt);
  if (fmt_str == NULL)
    return 0;

  /* If the format doesn't contain % args or %%, use strcpy.  */
  if (strchr (fmt_str, '%') == 0)
    {
      tree fn = implicit_built_in_decls[BUILT_IN_STRCPY];
      tree exp;

      if (arglist || ! fn)
        return 0;
      expand_expr (build_function_call_expr (fn, orig_arglist),
                   const0_rtx, VOIDmode, EXPAND_NORMAL);
      if (target == const0_rtx)
        return const0_rtx;
      exp = build_int_2 (strlen (fmt_str), 0);
      exp = fold (build1 (NOP_EXPR, integer_type_node, exp));
      return expand_expr (exp, target, mode, EXPAND_NORMAL);
    }
  /* If the format is "%s", use strcpy if the result isn't used.  */
  else if (strcmp (fmt_str, "%s") == 0)
    {
      tree fn, arg, len;
      fn = implicit_built_in_decls[BUILT_IN_STRCPY];

      if (! fn)
        return 0;

      if (! arglist || TREE_CHAIN (arglist))
        return 0;
      arg = TREE_VALUE (arglist);
      if (TREE_CODE (TREE_TYPE (arg)) != POINTER_TYPE)
        return 0;

      if (target != const0_rtx)
        {
          len = c_strlen (arg, 1);
          if (! len || TREE_CODE (len) != INTEGER_CST)
            return 0;
        }
      else
        len = NULL_TREE;

      arglist = build_tree_list (NULL_TREE, arg);
      arglist = tree_cons (NULL_TREE, dest, arglist);
      expand_expr (build_function_call_expr (fn, arglist),
                   const0_rtx, VOIDmode, EXPAND_NORMAL);

      if (target == const0_rtx)
        return const0_rtx;
      return expand_expr (len, target, mode, EXPAND_NORMAL);
    }

  return 0;
}
\f
/* Expand an expression EXP that calls a built-in function,
   with result going to TARGET if that's convenient
   (and in mode MODE if that's convenient).
   SUBTARGET may be used as the target for computing one of EXP's operands.
   IGNORE is nonzero if the value is to be ignored.  */

rtx
expand_builtin (tree exp, rtx target, rtx subtarget, enum machine_mode mode,
                int ignore)
{
  tree fndecl = TREE_OPERAND (TREE_OPERAND (exp, 0), 0);
  tree arglist = TREE_OPERAND (exp, 1);
  enum built_in_function fcode = DECL_FUNCTION_CODE (fndecl);
  enum machine_mode target_mode = TYPE_MODE (TREE_TYPE (exp));

  /* Perform postincrements before expanding builtin functions.  */
  emit_queue ();

  if (DECL_BUILT_IN_CLASS (fndecl) == BUILT_IN_MD)
    return (*targetm.expand_builtin) (exp, target, subtarget, mode, ignore);

  /* When not optimizing, generate calls to library functions for a certain
     set of builtins.  */
  if (!optimize
      && !CALLED_AS_BUILT_IN (fndecl)
      && DECL_ASSEMBLER_NAME_SET_P (fndecl)
      && fcode != BUILT_IN_ALLOCA)
    return expand_call (exp, target, ignore);

  /* The built-in function expanders test for target == const0_rtx
     to determine whether the function's result will be ignored.  */
  if (ignore)
    target = const0_rtx;

  /* If the result of a pure or const built-in function is ignored, and
     none of its arguments are volatile, we can avoid expanding the
     built-in call and just evaluate the arguments for side-effects.  */
  if (target == const0_rtx
      && (DECL_IS_PURE (fndecl) || TREE_READONLY (fndecl)))
    {
      bool volatilep = false;
      tree arg;

      for (arg = arglist; arg; arg = TREE_CHAIN (arg))
        if (TREE_THIS_VOLATILE (TREE_VALUE (arg)))
          {
            volatilep = true;
            break;
          }

      if (! volatilep)
        {
          for (arg = arglist; arg; arg = TREE_CHAIN (arg))
            expand_expr (TREE_VALUE (arg), const0_rtx,
                         VOIDmode, EXPAND_NORMAL);
          return const0_rtx;
        }
    }

  switch (fcode)
    {
    case BUILT_IN_ABS:
    case BUILT_IN_LABS:
    case BUILT_IN_LLABS:
    case BUILT_IN_IMAXABS:
      /* build_function_call changes these into ABS_EXPR.  */
      abort ();

    case BUILT_IN_FABS:
    case BUILT_IN_FABSF:
    case BUILT_IN_FABSL:
      target = expand_builtin_fabs (arglist, target, subtarget);
      if (target)
        return target;
      break;

    case BUILT_IN_CABS:
    case BUILT_IN_CABSF:
    case BUILT_IN_CABSL:
      if (flag_unsafe_math_optimizations)
        {
          target = expand_builtin_cabs (arglist, target);
          if (target)
            return target;
        }
      break;

    case BUILT_IN_CONJ:
    case BUILT_IN_CONJF:
    case BUILT_IN_CONJL:
    case BUILT_IN_CREAL:
    case BUILT_IN_CREALF:
    case BUILT_IN_CREALL:
    case BUILT_IN_CIMAG:
    case BUILT_IN_CIMAGF:
    case BUILT_IN_CIMAGL:
      /* expand_tree_builtin changes these into CONJ_EXPR, REALPART_EXPR
         and IMAGPART_EXPR.  */
      abort ();

    case BUILT_IN_SIN:
    case BUILT_IN_SINF:
    case BUILT_IN_SINL:
    case BUILT_IN_COS:
    case BUILT_IN_COSF:
    case BUILT_IN_COSL:
    case BUILT_IN_EXP:
    case BUILT_IN_EXPF:
    case BUILT_IN_EXPL:
    case BUILT_IN_LOG:
    case BUILT_IN_LOGF:
    case BUILT_IN_LOGL:
    case BUILT_IN_TAN:
    case BUILT_IN_TANF:
    case BUILT_IN_TANL:
    case BUILT_IN_ATAN:
    case BUILT_IN_ATANF:
    case BUILT_IN_ATANL:
      /* Treat these like sqrt only if unsafe math optimizations are allowed,
         because of possible accuracy problems.  */
      if (! flag_unsafe_math_optimizations)
        break;
    case BUILT_IN_SQRT:
    case BUILT_IN_SQRTF:
    case BUILT_IN_SQRTL:
    case BUILT_IN_FLOOR:
    case BUILT_IN_FLOORF:
    case BUILT_IN_FLOORL:
    case BUILT_IN_CEIL:
    case BUILT_IN_CEILF:
    case BUILT_IN_CEILL:
    case BUILT_IN_TRUNC:
    case BUILT_IN_TRUNCF:
    case BUILT_IN_TRUNCL:
    case BUILT_IN_ROUND:
    case BUILT_IN_ROUNDF:
    case BUILT_IN_ROUNDL:
    case BUILT_IN_NEARBYINT:
    case BUILT_IN_NEARBYINTF:
    case BUILT_IN_NEARBYINTL:
      target = expand_builtin_mathfn (exp, target, subtarget);
      if (target)
        return target;
      break;

    case BUILT_IN_POW:
    case BUILT_IN_POWF:
    case BUILT_IN_POWL:
      if (! flag_unsafe_math_optimizations)
        break;
      target = expand_builtin_pow (exp, target, subtarget);
      if (target)
        return target;
      break;

    case BUILT_IN_ATAN2:
    case BUILT_IN_ATAN2F:
    case BUILT_IN_ATAN2L:
      if (! flag_unsafe_math_optimizations)
        break;
      target = expand_builtin_mathfn_2 (exp, target, subtarget);
      if (target)
        return target;
      break;

    case BUILT_IN_APPLY_ARGS:
      return expand_builtin_apply_args ();

      /* __builtin_apply (FUNCTION, ARGUMENTS, ARGSIZE) invokes
         FUNCTION with a copy of the parameters described by
         ARGUMENTS, and ARGSIZE.  It returns a block of memory
         allocated on the stack into which is stored all the registers
         that might possibly be used for returning the result of a
         function.  ARGUMENTS is the value returned by
         __builtin_apply_args.  ARGSIZE is the number of bytes of
         arguments that must be copied.  ??? How should this value be
         computed?  We'll also need a safe worst case value for varargs
         functions.  */
    case BUILT_IN_APPLY:
      if (!validate_arglist (arglist, POINTER_TYPE,
                             POINTER_TYPE, INTEGER_TYPE, VOID_TYPE)
          && !validate_arglist (arglist, REFERENCE_TYPE,
                                POINTER_TYPE, INTEGER_TYPE, VOID_TYPE))
        return const0_rtx;
      else
        {
          int i;
          tree t;
          rtx ops[3];

          for (t = arglist, i = 0; t; t = TREE_CHAIN (t), i++)
            ops[i] = expand_expr (TREE_VALUE (t), NULL_RTX, VOIDmode, 0);

          return expand_builtin_apply (ops[0], ops[1], ops[2]);
        }

      /* __builtin_return (RESULT) causes the function to return the
         value described by RESULT.  RESULT is address of the block of
         memory returned by __builtin_apply.  */
    case BUILT_IN_RETURN:
      if (validate_arglist (arglist, POINTER_TYPE, VOID_TYPE))
        expand_builtin_return (expand_expr (TREE_VALUE (arglist),
                                            NULL_RTX, VOIDmode, 0));
      return const0_rtx;

    case BUILT_IN_SAVEREGS:
      return expand_builtin_saveregs ();

    case BUILT_IN_ARGS_INFO:
      return expand_builtin_args_info (arglist);

      /* Return the address of the first anonymous stack arg.  */
    case BUILT_IN_NEXT_ARG:
      return expand_builtin_next_arg (arglist);

    case BUILT_IN_CLASSIFY_TYPE:
      return expand_builtin_classify_type (arglist);

    case BUILT_IN_CONSTANT_P:
      return expand_builtin_constant_p (arglist, target_mode);

    case BUILT_IN_FRAME_ADDRESS:
    case BUILT_IN_RETURN_ADDRESS:
      return expand_builtin_frame_address (fndecl, arglist);

    /* Returns the address of the area where the structure is returned.
       0 otherwise.  */
    case BUILT_IN_AGGREGATE_INCOMING_ADDRESS:
      if (arglist != 0
          || ! AGGREGATE_TYPE_P (TREE_TYPE (TREE_TYPE (current_function_decl)))
          || GET_CODE (DECL_RTL (DECL_RESULT (current_function_decl))) != MEM)
        return const0_rtx;
      else
        return XEXP (DECL_RTL (DECL_RESULT (current_function_decl)), 0);

    case BUILT_IN_ALLOCA:
      target = expand_builtin_alloca (arglist, target);
      if (target)
        return target;
      break;

    case BUILT_IN_FFS:
    case BUILT_IN_FFSL:
    case BUILT_IN_FFSLL:
      target = expand_builtin_unop (target_mode, arglist, target,
                                    subtarget, ffs_optab);
      if (target)
        return target;
      break;

    case BUILT_IN_CLZ:
    case BUILT_IN_CLZL:
    case BUILT_IN_CLZLL:
      target = expand_builtin_unop (target_mode, arglist, target,
                                    subtarget, clz_optab);
      if (target)
        return target;
      break;

    case BUILT_IN_CTZ:
    case BUILT_IN_CTZL:
    case BUILT_IN_CTZLL:
      target = expand_builtin_unop (target_mode, arglist, target,
                                    subtarget, ctz_optab);
      if (target)
        return target;
      break;

    case BUILT_IN_POPCOUNT:
    case BUILT_IN_POPCOUNTL:
    case BUILT_IN_POPCOUNTLL:
      target = expand_builtin_unop (target_mode, arglist, target,
                                    subtarget, popcount_optab);
      if (target)
        return target;
      break;

    case BUILT_IN_PARITY:
    case BUILT_IN_PARITYL:
    case BUILT_IN_PARITYLL:
      target = expand_builtin_unop (target_mode, arglist, target,
                                    subtarget, parity_optab);
      if (target)
        return target;
      break;

    case BUILT_IN_STRLEN:
      target = expand_builtin_strlen (arglist, target, target_mode);
      if (target)
        return target;
      break;

    case BUILT_IN_STRCPY:
      target = expand_builtin_strcpy (arglist, target, mode);
      if (target)
        return target;
      break;

    case BUILT_IN_STRNCPY:
      target = expand_builtin_strncpy (arglist, target, mode);
      if (target)
        return target;
      break;

    case BUILT_IN_STPCPY:
      target = expand_builtin_stpcpy (arglist, target, mode);
      if (target)
        return target;
      break;

    case BUILT_IN_STRCAT:
      target = expand_builtin_strcat (arglist, target, mode);
      if (target)
        return target;
      break;

    case BUILT_IN_STRNCAT:
      target = expand_builtin_strncat (arglist, target, mode);
      if (target)
        return target;
      break;

    case BUILT_IN_STRSPN:
      target = expand_builtin_strspn (arglist, target, mode);
      if (target)
        return target;
      break;

    case BUILT_IN_STRCSPN:
      target = expand_builtin_strcspn (arglist, target, mode);
      if (target)
        return target;
      break;

    case BUILT_IN_STRSTR:
      target = expand_builtin_strstr (arglist, target, mode);
      if (target)
        return target;
      break;

    case BUILT_IN_STRPBRK:
      target = expand_builtin_strpbrk (arglist, target, mode);
      if (target)
        return target;
      break;

    case BUILT_IN_INDEX:
    case BUILT_IN_STRCHR:
      target = expand_builtin_strchr (arglist, target, mode);
      if (target)
        return target;
      break;

    case BUILT_IN_RINDEX:
    case BUILT_IN_STRRCHR:
      target = expand_builtin_strrchr (arglist, target, mode);
      if (target)
        return target;
      break;

    case BUILT_IN_MEMCPY:
      target = expand_builtin_memcpy (arglist, target, mode);
      if (target)
        return target;
      break;

    case BUILT_IN_MEMPCPY:
      target = expand_builtin_mempcpy (arglist, target, mode, /*endp=*/ 1);
      if (target)
        return target;
      break;

    case BUILT_IN_MEMMOVE:
      target = expand_builtin_memmove (arglist, target, mode);
      if (target)
        return target;
      break;

    case BUILT_IN_BCOPY:
      target = expand_builtin_bcopy (arglist);
      if (target)
        return target;
      break;

    case BUILT_IN_MEMSET:
      target = expand_builtin_memset (arglist, target, mode);
      if (target)
        return target;
      break;

    case BUILT_IN_BZERO:
      target = expand_builtin_bzero (arglist);
      if (target)
        return target;
      break;

    case BUILT_IN_STRCMP:
      target = expand_builtin_strcmp (exp, target, mode);
      if (target)
        return target;
      break;

    case BUILT_IN_STRNCMP:
      target = expand_builtin_strncmp (exp, target, mode);
      if (target)
        return target;
      break;

    case BUILT_IN_BCMP:
    case BUILT_IN_MEMCMP:
      target = expand_builtin_memcmp (exp, arglist, target, mode);
      if (target)
        return target;
      break;

    case BUILT_IN_SETJMP:
      target = expand_builtin_setjmp (arglist, target);
      if (target)
        return target;
      break;

      /* __builtin_longjmp is passed a pointer to an array of five words.
         It's similar to the C library longjmp function but works with
         __builtin_setjmp above.  */
    case BUILT_IN_LONGJMP:
      if (!validate_arglist (arglist, POINTER_TYPE, INTEGER_TYPE, VOID_TYPE))
        break;
      else
        {
          rtx buf_addr = expand_expr (TREE_VALUE (arglist), subtarget,
                                      VOIDmode, 0);
          rtx value = expand_expr (TREE_VALUE (TREE_CHAIN (arglist)),
                                   NULL_RTX, VOIDmode, 0);

          if (value != const1_rtx)
            {
              error ("__builtin_longjmp second argument must be 1");
              return const0_rtx;
            }

          expand_builtin_longjmp (buf_addr, value);
          return const0_rtx;
        }

    case BUILT_IN_TRAP:
      expand_builtin_trap ();
      return const0_rtx;

    case BUILT_IN_PRINTF:
      target = expand_builtin_printf (arglist, target, mode, false);
      if (target)
        return target;
      break;

    case BUILT_IN_PRINTF_UNLOCKED:
      target = expand_builtin_printf (arglist, target, mode, true);
      if (target)
        return target;
      break;

    case BUILT_IN_FPUTS:
      target = expand_builtin_fputs (arglist, target, false);
      if (target)
        return target;
      break;

    case BUILT_IN_FPUTS_UNLOCKED:
      target = expand_builtin_fputs (arglist, target, true);
      if (target)
        return target;
      break;

    case BUILT_IN_FPRINTF:
      target = expand_builtin_fprintf (arglist, target, mode, false);
      if (target)
        return target;
      break;

    case BUILT_IN_FPRINTF_UNLOCKED:
      target = expand_builtin_fprintf (arglist, target, mode, true);
      if (target)
        return target;
      break;

    case BUILT_IN_SPRINTF:
      target = expand_builtin_sprintf (arglist, target, mode);
      if (target)
        return target;
      break;

      /* Various hooks for the DWARF 2 __throw routine.  */
    case BUILT_IN_UNWIND_INIT:
      expand_builtin_unwind_init ();
      return const0_rtx;
    case BUILT_IN_DWARF_CFA:
      return virtual_cfa_rtx;
#ifdef DWARF2_UNWIND_INFO
    case BUILT_IN_DWARF_SP_COLUMN:
      return expand_builtin_dwarf_sp_column ();
    case BUILT_IN_INIT_DWARF_REG_SIZES:
      expand_builtin_init_dwarf_reg_sizes (TREE_VALUE (arglist));
      return const0_rtx;
#endif
    case BUILT_IN_FROB_RETURN_ADDR:
      return expand_builtin_frob_return_addr (TREE_VALUE (arglist));
    case BUILT_IN_EXTRACT_RETURN_ADDR:
      return expand_builtin_extract_return_addr (TREE_VALUE (arglist));
    case BUILT_IN_EH_RETURN:
      expand_builtin_eh_return (TREE_VALUE (arglist),
                                TREE_VALUE (TREE_CHAIN (arglist)));
      return const0_rtx;
#ifdef EH_RETURN_DATA_REGNO
    case BUILT_IN_EH_RETURN_DATA_REGNO:
      return expand_builtin_eh_return_data_regno (arglist);
#endif
    case BUILT_IN_VA_START:
    case BUILT_IN_STDARG_START:
      return expand_builtin_va_start (arglist);
    case BUILT_IN_VA_END:
      return expand_builtin_va_end (arglist);
    case BUILT_IN_VA_COPY:
      return expand_builtin_va_copy (arglist);
    case BUILT_IN_EXPECT:
      return expand_builtin_expect (arglist, target);
    case BUILT_IN_PREFETCH:
      expand_builtin_prefetch (arglist);
      return const0_rtx;


    default:    /* just do library call, if unknown builtin */
      if (!DECL_ASSEMBLER_NAME_SET_P (fndecl))
        error ("built-in function `%s' not currently supported",
               IDENTIFIER_POINTER (DECL_NAME (fndecl)));
    }

  /* The switch statement above can drop through to cause the function
     to be called normally.  */
  return expand_call (exp, target, ignore);
}

/* Determine whether a tree node represents a call to a built-in
   math function.  If the tree T is a call to a built-in function
   taking a single real argument, then the return value is the
   DECL_FUNCTION_CODE of the call, e.g. BUILT_IN_SQRT.  Otherwise
   the return value is END_BUILTINS.  */

enum built_in_function
builtin_mathfn_code (tree t)
{
  tree fndecl, arglist;

  if (TREE_CODE (t) != CALL_EXPR
      || TREE_CODE (TREE_OPERAND (t, 0)) != ADDR_EXPR)
    return END_BUILTINS;

  fndecl = TREE_OPERAND (TREE_OPERAND (t, 0), 0);
  if (TREE_CODE (fndecl) != FUNCTION_DECL
      || ! DECL_BUILT_IN (fndecl)
      || DECL_BUILT_IN_CLASS (fndecl) == BUILT_IN_MD)
    return END_BUILTINS;

  arglist = TREE_OPERAND (t, 1);
  if (! arglist
      || TREE_CODE (TREE_TYPE (TREE_VALUE (arglist))) != REAL_TYPE)
    return END_BUILTINS;

  arglist = TREE_CHAIN (arglist);
  switch (DECL_FUNCTION_CODE (fndecl))
    {
    case BUILT_IN_POW:
    case BUILT_IN_POWF:
    case BUILT_IN_POWL:
    case BUILT_IN_ATAN2:
    case BUILT_IN_ATAN2F:
    case BUILT_IN_ATAN2L:
      if (! arglist
          || TREE_CODE (TREE_TYPE (TREE_VALUE (arglist))) != REAL_TYPE
          || TREE_CHAIN (arglist))
        return END_BUILTINS;
      break;

    default:
      if (arglist)
        return END_BUILTINS;
      break;
    }

  return DECL_FUNCTION_CODE (fndecl);
}

/* Fold a call to __builtin_constant_p, if we know it will evaluate to a
   constant.  ARGLIST is the argument list of the call.  */

static tree
fold_builtin_constant_p (tree arglist)
{
  if (arglist == 0)
    return 0;

  arglist = TREE_VALUE (arglist);

  /* We return 1 for a numeric type that's known to be a constant
     value at compile-time or for an aggregate type that's a
     literal constant.  */
  STRIP_NOPS (arglist);

  /* If we know this is a constant, emit the constant of one.  */
  if (TREE_CODE_CLASS (TREE_CODE (arglist)) == 'c'
      || (TREE_CODE (arglist) == CONSTRUCTOR
          && TREE_CONSTANT (arglist))
      || (TREE_CODE (arglist) == ADDR_EXPR
          && TREE_CODE (TREE_OPERAND (arglist, 0)) == STRING_CST))
    return integer_one_node;

  /* If we aren't going to be running CSE or this expression
     has side effects, show we don't know it to be a constant.
     Likewise if it's a pointer or aggregate type since in those
     case we only want literals, since those are only optimized
     when generating RTL, not later.
     And finally, if we are compiling an initializer, not code, we
     need to return a definite result now; there's not going to be any
     more optimization done.  */
  if (TREE_SIDE_EFFECTS (arglist) || cse_not_expected
      || AGGREGATE_TYPE_P (TREE_TYPE (arglist))
      || POINTER_TYPE_P (TREE_TYPE (arglist))
      || cfun == 0)
    return integer_zero_node;

  return 0;
}

/* Fold a call to __builtin_classify_type.  */

static tree
fold_builtin_classify_type (tree arglist)
{
  if (arglist == 0)
    return build_int_2 (no_type_class, 0);

  return build_int_2 (type_to_class (TREE_TYPE (TREE_VALUE (arglist))), 0);
}

/* Fold a call to __builtin_inf or __builtin_huge_val.  */

static tree
fold_builtin_inf (tree type, int warn)
{
  REAL_VALUE_TYPE real;

  if (!MODE_HAS_INFINITIES (TYPE_MODE (type)) && warn)
    warning ("target format does not support infinity");

  real_inf (&real);
  return build_real (type, real);
}

/* Fold a call to __builtin_nan or __builtin_nans.  */

static tree
fold_builtin_nan (tree arglist, tree type, int quiet)
{
  REAL_VALUE_TYPE real;
  const char *str;

  if (!validate_arglist (arglist, POINTER_TYPE, VOID_TYPE))
    return 0;
  str = c_getstr (TREE_VALUE (arglist));
  if (!str)
    return 0;

  if (!real_nan (&real, str, quiet, TYPE_MODE (type)))
    return 0;

  return build_real (type, real);
}

/* Return true if the floating point expression T has an integer value.
   We also allow +Inf, -Inf and NaN to be considered integer values.  */

static bool
integer_valued_real_p (tree t)
{
  switch (TREE_CODE (t))
    {
    case FLOAT_EXPR:
      return true;

    case ABS_EXPR:
    case SAVE_EXPR:
    case NON_LVALUE_EXPR:
      return integer_valued_real_p (TREE_OPERAND (t, 0));

    case COMPOUND_EXPR:
    case MODIFY_EXPR:
    case BIND_EXPR:
      return integer_valued_real_p (TREE_OPERAND (t, 1));

    case PLUS_EXPR:
    case MINUS_EXPR:
    case MULT_EXPR:
    case MIN_EXPR:
    case MAX_EXPR:
      return integer_valued_real_p (TREE_OPERAND (t, 0))
             && integer_valued_real_p (TREE_OPERAND (t, 1));

    case COND_EXPR:
      return integer_valued_real_p (TREE_OPERAND (t, 1))
             && integer_valued_real_p (TREE_OPERAND (t, 2));

    case REAL_CST:
      if (! TREE_CONSTANT_OVERFLOW (t))
      {
        REAL_VALUE_TYPE c, cint;

        c = TREE_REAL_CST (t);
        real_trunc (&cint, TYPE_MODE (TREE_TYPE (t)), &c);
        return real_identical (&c, &cint);
      }

    case NOP_EXPR:
      {
        tree type = TREE_TYPE (TREE_OPERAND (t, 0));
        if (TREE_CODE (type) == INTEGER_TYPE)
          return true;
        if (TREE_CODE (type) == REAL_TYPE)
          return integer_valued_real_p (TREE_OPERAND (t, 0));
        break;
      }

    case CALL_EXPR:
      switch (builtin_mathfn_code (t))
        {
        case BUILT_IN_CEIL:
        case BUILT_IN_CEILF:
        case BUILT_IN_CEILL:
        case BUILT_IN_FLOOR:
        case BUILT_IN_FLOORF:
        case BUILT_IN_FLOORL:
        case BUILT_IN_NEARBYINT:
        case BUILT_IN_NEARBYINTF:
        case BUILT_IN_NEARBYINTL:
        case BUILT_IN_ROUND:
        case BUILT_IN_ROUNDF:
        case BUILT_IN_ROUNDL:
        case BUILT_IN_TRUNC:
        case BUILT_IN_TRUNCF:
        case BUILT_IN_TRUNCL:
          return true;

        default:
          break;
        }
      break;

    default:
      break;
    }
  return false;
}

/* EXP is assumed to be builtin call where truncation can be propagated
   across (for instance floor((double)f) == (double)floorf (f).
   Do the transformation.  */

static tree
fold_trunc_transparent_mathfn (tree exp)
{
  tree fndecl = TREE_OPERAND (TREE_OPERAND (exp, 0), 0);
  tree arglist = TREE_OPERAND (exp, 1);
  enum built_in_function fcode = DECL_FUNCTION_CODE (fndecl);
  tree arg;

  if (! validate_arglist (arglist, REAL_TYPE, VOID_TYPE))
    return 0;

  arg = TREE_VALUE (arglist);
  /* Integer rounding functions are idempotent.  */
  if (fcode == builtin_mathfn_code (arg))
    return arg;

  /* If argument is already integer valued, and we don't need to worry
     about setting errno, there's no need to perform rounding.  */
  if (! flag_errno_math && integer_valued_real_p (arg))
    return arg;

  if (optimize)
    {
      tree arg0 = strip_float_extensions (arg);
      tree ftype = TREE_TYPE (exp);
      tree newtype = TREE_TYPE (arg0);
      tree decl;

      if (TYPE_PRECISION (newtype) < TYPE_PRECISION (ftype)
          && (decl = mathfn_built_in (newtype, fcode)))
        {
          arglist =
            build_tree_list (NULL_TREE, fold (convert (newtype, arg0)));
          return convert (ftype,
                          build_function_call_expr (decl, arglist));
        }
    }
  return 0;
}

/* Fold function call to builtin cabs, cabsf or cabsl.  FNDECL is the
   function's DECL, ARGLIST is the argument list and TYPE is the return
   type.  Return NULL_TREE if no simplification can be made.  */

static tree
fold_builtin_cabs (tree fndecl, tree arglist, tree type)
{
  tree arg;

  if (!arglist || TREE_CHAIN (arglist))
    return NULL_TREE;

  arg = TREE_VALUE (arglist);
  if (TREE_CODE (TREE_TYPE (arg)) != COMPLEX_TYPE
      || TREE_CODE (TREE_TYPE (TREE_TYPE (arg))) != REAL_TYPE)
    return NULL_TREE;

  /* Evaluate cabs of a constant at compile-time.  */
  if (flag_unsafe_math_optimizations
      && TREE_CODE (arg) == COMPLEX_CST
      && TREE_CODE (TREE_REALPART (arg)) == REAL_CST
      && TREE_CODE (TREE_IMAGPART (arg)) == REAL_CST
      && ! TREE_CONSTANT_OVERFLOW (TREE_REALPART (arg))
      && ! TREE_CONSTANT_OVERFLOW (TREE_IMAGPART (arg)))
    {
      REAL_VALUE_TYPE r, i;

      r = TREE_REAL_CST (TREE_REALPART (arg));
      i = TREE_REAL_CST (TREE_IMAGPART (arg));

      real_arithmetic (&r, MULT_EXPR, &r, &r);
      real_arithmetic (&i, MULT_EXPR, &i, &i);
      real_arithmetic (&r, PLUS_EXPR, &r, &i);
      if (real_sqrt (&r, TYPE_MODE (type), &r)
          || ! flag_trapping_math)
        return build_real (type, r);
    }

  /* If either part is zero, cabs is fabs of the other.  */
  if (TREE_CODE (arg) == COMPLEX_EXPR
      && real_zerop (TREE_OPERAND (arg, 0)))
    return fold (build1 (ABS_EXPR, type, TREE_OPERAND (arg, 1)));
  if (TREE_CODE (arg) == COMPLEX_EXPR
      && real_zerop (TREE_OPERAND (arg, 1)))
    return fold (build1 (ABS_EXPR, type, TREE_OPERAND (arg, 0)));

  if (flag_unsafe_math_optimizations)
    {
      enum built_in_function fcode;
      tree sqrtfn;

      fcode = DECL_FUNCTION_CODE (fndecl);
      if (fcode == BUILT_IN_CABS)
        sqrtfn = implicit_built_in_decls[BUILT_IN_SQRT];
      else if (fcode == BUILT_IN_CABSF)
        sqrtfn = implicit_built_in_decls[BUILT_IN_SQRTF];
      else if (fcode == BUILT_IN_CABSL)
        sqrtfn = implicit_built_in_decls[BUILT_IN_SQRTL];
      else
        sqrtfn = NULL_TREE;

      if (sqrtfn != NULL_TREE)
        {
          tree rpart, ipart, result, arglist;

          rpart = fold (build1 (REALPART_EXPR, type, arg));
          ipart = fold (build1 (IMAGPART_EXPR, type, arg));

          rpart = save_expr (rpart);
          ipart = save_expr (ipart);

          result = fold (build (PLUS_EXPR, type,
                                fold (build (MULT_EXPR, type,
                                             rpart, rpart)),
                                fold (build (MULT_EXPR, type,
                                             ipart, ipart))));

          arglist = build_tree_list (NULL_TREE, result);
          return build_function_call_expr (sqrtfn, arglist);
        }
    }

  return NULL_TREE;
}

/* Fold function call to builtin trunc, truncf or truncl.  Return
   NULL_TREE if no simplification can be made.  */

static tree
fold_builtin_trunc (tree exp)
{
  tree arglist = TREE_OPERAND (exp, 1);
  tree arg;

  if (! validate_arglist (arglist, REAL_TYPE, VOID_TYPE))
    return 0;

  /* Optimize trunc of constant value.  */
  arg = TREE_VALUE (arglist);
  if (TREE_CODE (arg) == REAL_CST && ! TREE_CONSTANT_OVERFLOW (arg))
    {
      REAL_VALUE_TYPE r, x;
      tree type = TREE_TYPE (exp);

      x = TREE_REAL_CST (arg);
      real_trunc (&r, TYPE_MODE (type), &x);
      return build_real (type, r);
    }

  return fold_trunc_transparent_mathfn (exp);
}

/* Fold function call to builtin floor, floorf or floorl.  Return
   NULL_TREE if no simplification can be made.  */

static tree
fold_builtin_floor (tree exp)
{
  tree arglist = TREE_OPERAND (exp, 1);
  tree arg;

  if (! validate_arglist (arglist, REAL_TYPE, VOID_TYPE))
    return 0;

  /* Optimize floor of constant value.  */
  arg = TREE_VALUE (arglist);
  if (TREE_CODE (arg) == REAL_CST && ! TREE_CONSTANT_OVERFLOW (arg))
    {
      REAL_VALUE_TYPE x;

      x = TREE_REAL_CST (arg);
      if (! REAL_VALUE_ISNAN (x) || ! flag_errno_math)
        {
          tree type = TREE_TYPE (exp);
          REAL_VALUE_TYPE r;

          real_floor (&r, TYPE_MODE (type), &x);
          return build_real (type, r);
        }
    }

  return fold_trunc_transparent_mathfn (exp);
}

/* Fold function call to builtin ceil, ceilf or ceill.  Return
   NULL_TREE if no simplification can be made.  */

static tree
fold_builtin_ceil (tree exp)
{
  tree arglist = TREE_OPERAND (exp, 1);
  tree arg;

  if (! validate_arglist (arglist, REAL_TYPE, VOID_TYPE))
    return 0;

  /* Optimize ceil of constant value.  */
  arg = TREE_VALUE (arglist);
  if (TREE_CODE (arg) == REAL_CST && ! TREE_CONSTANT_OVERFLOW (arg))
    {
      REAL_VALUE_TYPE x;

      x = TREE_REAL_CST (arg);
      if (! REAL_VALUE_ISNAN (x) || ! flag_errno_math)
        {
          tree type = TREE_TYPE (exp);
          REAL_VALUE_TYPE r;

          real_ceil (&r, TYPE_MODE (type), &x);
          return build_real (type, r);
        }
    }

  return fold_trunc_transparent_mathfn (exp);
}

/* Used by constant folding to eliminate some builtin calls early.  EXP is
   the CALL_EXPR of a call to a builtin function.  */

tree
fold_builtin (tree exp)
{
  tree fndecl = TREE_OPERAND (TREE_OPERAND (exp, 0), 0);
  tree arglist = TREE_OPERAND (exp, 1);
  tree type = TREE_TYPE (TREE_TYPE (fndecl));

  if (DECL_BUILT_IN_CLASS (fndecl) == BUILT_IN_MD)
    return 0;

  switch (DECL_FUNCTION_CODE (fndecl))
    {
    case BUILT_IN_CONSTANT_P:
      return fold_builtin_constant_p (arglist);

    case BUILT_IN_CLASSIFY_TYPE:
      return fold_builtin_classify_type (arglist);

    case BUILT_IN_STRLEN:
      if (validate_arglist (arglist, POINTER_TYPE, VOID_TYPE))
        {
          tree len = c_strlen (TREE_VALUE (arglist), 0);
          if (len)
            {
              /* Convert from the internal "sizetype" type to "size_t".  */
              if (size_type_node)
                len = convert (size_type_node, len);
              return len;
            }
        }
      break;

    case BUILT_IN_FABS:
    case BUILT_IN_FABSF:
    case BUILT_IN_FABSL:
      if (validate_arglist (arglist, REAL_TYPE, VOID_TYPE))
        return fold (build1 (ABS_EXPR, type, TREE_VALUE (arglist)));
      break;

    case BUILT_IN_CABS:
    case BUILT_IN_CABSF:
    case BUILT_IN_CABSL:
      return fold_builtin_cabs (fndecl, arglist, type);

    case BUILT_IN_SQRT:
    case BUILT_IN_SQRTF:
    case BUILT_IN_SQRTL:
      if (validate_arglist (arglist, REAL_TYPE, VOID_TYPE))
        {
          enum built_in_function fcode;
          tree arg = TREE_VALUE (arglist);

          /* Optimize sqrt of constant value.  */
          if (TREE_CODE (arg) == REAL_CST
              && ! TREE_CONSTANT_OVERFLOW (arg))
            {
              REAL_VALUE_TYPE r, x;

              x = TREE_REAL_CST (arg);
              if (real_sqrt (&r, TYPE_MODE (type), &x)
                  || (!flag_trapping_math && !flag_errno_math))
                return build_real (type, r);
            }

          /* Optimize sqrt(exp(x)) = exp(x*0.5).  */
          fcode = builtin_mathfn_code (arg);
          if (flag_unsafe_math_optimizations
              && (fcode == BUILT_IN_EXP
                  || fcode == BUILT_IN_EXPF
                  || fcode == BUILT_IN_EXPL))
            {
              tree expfn = TREE_OPERAND (TREE_OPERAND (arg, 0), 0);
              arg = fold (build (MULT_EXPR, type,
                                 TREE_VALUE (TREE_OPERAND (arg, 1)),
                                 build_real (type, dconsthalf)));
              arglist = build_tree_list (NULL_TREE, arg);
              return build_function_call_expr (expfn, arglist);
            }

          /* Optimize sqrt(pow(x,y)) = pow(x,y*0.5).  */
          if (flag_unsafe_math_optimizations
              && (fcode == BUILT_IN_POW
                  || fcode == BUILT_IN_POWF
                  || fcode == BUILT_IN_POWL))
            {
              tree powfn = TREE_OPERAND (TREE_OPERAND (arg, 0), 0);
              tree arg0 = TREE_VALUE (TREE_OPERAND (arg, 1));
              tree arg1 = TREE_VALUE (TREE_CHAIN (TREE_OPERAND (arg, 1)));
              tree narg1 = fold (build (MULT_EXPR, type, arg1,
                                        build_real (type, dconsthalf)));
              arglist = tree_cons (NULL_TREE, arg0,
                                   build_tree_list (NULL_TREE, narg1));
              return build_function_call_expr (powfn, arglist);
            }
        }
      break;

    case BUILT_IN_SIN:
    case BUILT_IN_SINF:
    case BUILT_IN_SINL:
      if (validate_arglist (arglist, REAL_TYPE, VOID_TYPE))
        {
          tree arg = TREE_VALUE (arglist);

          /* Optimize sin(0.0) = 0.0.  */
          if (real_zerop (arg))
            return arg;
        }
      break;

    case BUILT_IN_COS:
    case BUILT_IN_COSF:
    case BUILT_IN_COSL:
      if (validate_arglist (arglist, REAL_TYPE, VOID_TYPE))
        {
          tree arg = TREE_VALUE (arglist);

          /* Optimize cos(0.0) = 1.0.  */
          if (real_zerop (arg))
            return build_real (type, dconst1);

          /* Optimize cos(-x) into cos(x).  */
          if (TREE_CODE (arg) == NEGATE_EXPR)
            {
              tree arglist = build_tree_list (NULL_TREE,
                                              TREE_OPERAND (arg, 0));
              return build_function_call_expr (fndecl, arglist);
            }
        }
      break;

    case BUILT_IN_EXP:
    case BUILT_IN_EXPF:
    case BUILT_IN_EXPL:
      if (validate_arglist (arglist, REAL_TYPE, VOID_TYPE))
        {
          enum built_in_function fcode;
          tree arg = TREE_VALUE (arglist);

          /* Optimize exp(0.0) = 1.0.  */
          if (real_zerop (arg))
            return build_real (type, dconst1);

          /* Optimize exp(1.0) = e.  */
          if (real_onep (arg))
            {
              REAL_VALUE_TYPE cst;

              if (! builtin_dconsts_init)
                init_builtin_dconsts ();
              real_convert (&cst, TYPE_MODE (type), &dconste);
              return build_real (type, cst);
            }

          /* Attempt to evaluate exp at compile-time.  */
          if (flag_unsafe_math_optimizations
              && TREE_CODE (arg) == REAL_CST
              && ! TREE_CONSTANT_OVERFLOW (arg))
            {
              REAL_VALUE_TYPE cint;
              REAL_VALUE_TYPE c;
              HOST_WIDE_INT n;

              c = TREE_REAL_CST (arg);
              n = real_to_integer (&c);
              real_from_integer (&cint, VOIDmode, n,
                                 n < 0 ? -1 : 0, 0);
              if (real_identical (&c, &cint))
                {
                  REAL_VALUE_TYPE x;

                  if (! builtin_dconsts_init)
                    init_builtin_dconsts ();
                  real_powi (&x, TYPE_MODE (type), &dconste, n);
                  return build_real (type, x);
                }
            }

          /* Optimize exp(log(x)) = x.  */
          fcode = builtin_mathfn_code (arg);
          if (flag_unsafe_math_optimizations
              && (fcode == BUILT_IN_LOG
                  || fcode == BUILT_IN_LOGF
                  || fcode == BUILT_IN_LOGL))
            return TREE_VALUE (TREE_OPERAND (arg, 1));
        }
      break;

    case BUILT_IN_LOG:
    case BUILT_IN_LOGF:
    case BUILT_IN_LOGL:
      if (validate_arglist (arglist, REAL_TYPE, VOID_TYPE))
        {
          enum built_in_function fcode;
          tree arg = TREE_VALUE (arglist);

          /* Optimize log(1.0) = 0.0.  */
          if (real_onep (arg))
            return build_real (type, dconst0);

          /* Optimize log(exp(x)) = x.  */
          fcode = builtin_mathfn_code (arg);
          if (flag_unsafe_math_optimizations
              && (fcode == BUILT_IN_EXP
                  || fcode == BUILT_IN_EXPF
                  || fcode == BUILT_IN_EXPL))
            return TREE_VALUE (TREE_OPERAND (arg, 1));

          /* Optimize log(sqrt(x)) = log(x)*0.5.  */
          if (flag_unsafe_math_optimizations
              && (fcode == BUILT_IN_SQRT
                  || fcode == BUILT_IN_SQRTF
                  || fcode == BUILT_IN_SQRTL))
            {
              tree logfn = build_function_call_expr (fndecl,
                                                     TREE_OPERAND (arg, 1));
              return fold (build (MULT_EXPR, type, logfn,
                                  build_real (type, dconsthalf)));
            }

          /* Optimize log(pow(x,y)) = y*log(x).  */
          if (flag_unsafe_math_optimizations
              && (fcode == BUILT_IN_POW
                  || fcode == BUILT_IN_POWF
                  || fcode == BUILT_IN_POWL))
            {
              tree arg0, arg1, logfn;

              arg0 = TREE_VALUE (TREE_OPERAND (arg, 1));
              arg1 = TREE_VALUE (TREE_CHAIN (TREE_OPERAND (arg, 1)));
              arglist = build_tree_list (NULL_TREE, arg0);
              logfn = build_function_call_expr (fndecl, arglist);
              return fold (build (MULT_EXPR, type, arg1, logfn));
            }
        }
      break;

    case BUILT_IN_TAN:
    case BUILT_IN_TANF:
    case BUILT_IN_TANL:
      if (validate_arglist (arglist, REAL_TYPE, VOID_TYPE))
        {
          enum built_in_function fcode;
          tree arg = TREE_VALUE (arglist);

          /* Optimize tan(0.0) = 0.0.  */
          if (real_zerop (arg))
            return arg;

          /* Optimize tan(atan(x)) = x.  */
          fcode = builtin_mathfn_code (arg);
          if (flag_unsafe_math_optimizations
              && (fcode == BUILT_IN_ATAN
                  || fcode == BUILT_IN_ATANF
                  || fcode == BUILT_IN_ATANL))
            return TREE_VALUE (TREE_OPERAND (arg, 1));
        }
      break;

    case BUILT_IN_ATAN:
    case BUILT_IN_ATANF:
    case BUILT_IN_ATANL:
      if (validate_arglist (arglist, REAL_TYPE, VOID_TYPE))
        {
          tree arg = TREE_VALUE (arglist);

          /* Optimize atan(0.0) = 0.0.  */
          if (real_zerop (arg))
            return arg;

          /* Optimize atan(1.0) = pi/4.  */
          if (real_onep (arg))
            {
              REAL_VALUE_TYPE cst;

              if (! builtin_dconsts_init)
                init_builtin_dconsts ();
              real_convert (&cst, TYPE_MODE (type), &dconstpi);
              cst.exp -= 2;
              return build_real (type, cst);
            }
        }
      break;

    case BUILT_IN_POW:
    case BUILT_IN_POWF:
    case BUILT_IN_POWL:
      if (validate_arglist (arglist, REAL_TYPE, REAL_TYPE, VOID_TYPE))
        {
          enum built_in_function fcode;
          tree arg0 = TREE_VALUE (arglist);
          tree arg1 = TREE_VALUE (TREE_CHAIN (arglist));

          /* Optimize pow(1.0,y) = 1.0.  */
          if (real_onep (arg0))
            return omit_one_operand (type, build_real (type, dconst1), arg1);

          if (TREE_CODE (arg1) == REAL_CST
              && ! TREE_CONSTANT_OVERFLOW (arg1))
            {
              REAL_VALUE_TYPE c;
              c = TREE_REAL_CST (arg1);

              /* Optimize pow(x,0.0) = 1.0.  */
              if (REAL_VALUES_EQUAL (c, dconst0))
                return omit_one_operand (type, build_real (type, dconst1),
                                         arg0);

              /* Optimize pow(x,1.0) = x.  */
              if (REAL_VALUES_EQUAL (c, dconst1))
                return arg0;

              /* Optimize pow(x,-1.0) = 1.0/x.  */
              if (REAL_VALUES_EQUAL (c, dconstm1))
                return fold (build (RDIV_EXPR, type,
                                    build_real (type, dconst1),
                                    arg0));

              /* Optimize pow(x,0.5) = sqrt(x).  */
              if (flag_unsafe_math_optimizations
                  && REAL_VALUES_EQUAL (c, dconsthalf))
                {
                  tree sqrtfn;

                  fcode = DECL_FUNCTION_CODE (fndecl);
                  if (fcode == BUILT_IN_POW)
                    sqrtfn = implicit_built_in_decls[BUILT_IN_SQRT];
                  else if (fcode == BUILT_IN_POWF)
                    sqrtfn = implicit_built_in_decls[BUILT_IN_SQRTF];
                  else if (fcode == BUILT_IN_POWL)
                    sqrtfn = implicit_built_in_decls[BUILT_IN_SQRTL];
                  else
                    sqrtfn = NULL_TREE;

                  if (sqrtfn != NULL_TREE)
                    {
                      tree arglist = build_tree_list (NULL_TREE, arg0);
                      return build_function_call_expr (sqrtfn, arglist);
                    }
                }

              /* Attempt to evaluate pow at compile-time.  */
              if (TREE_CODE (arg0) == REAL_CST
                  && ! TREE_CONSTANT_OVERFLOW (arg0))
                {
                  REAL_VALUE_TYPE cint;
                  HOST_WIDE_INT n;

                  n = real_to_integer (&c);
                  real_from_integer (&cint, VOIDmode, n,
                                     n < 0 ? -1 : 0, 0);
                  if (real_identical (&c, &cint))
                    {
                      REAL_VALUE_TYPE x;
                      bool inexact;

                      x = TREE_REAL_CST (arg0);
                      inexact = real_powi (&x, TYPE_MODE (type), &x, n);
                      if (flag_unsafe_math_optimizations || !inexact)
                        return build_real (type, x);
                    }
                }
            }

          /* Optimize pow(exp(x),y) = exp(x*y).  */
          fcode = builtin_mathfn_code (arg0);
          if (flag_unsafe_math_optimizations
              && (fcode == BUILT_IN_EXP
                  || fcode == BUILT_IN_EXPF
                  || fcode == BUILT_IN_EXPL))
            {
              tree expfn = TREE_OPERAND (TREE_OPERAND (arg0, 0), 0);
              tree arg = TREE_VALUE (TREE_OPERAND (arg0, 1));
              arg = fold (build (MULT_EXPR, type, arg, arg1));
              arglist = build_tree_list (NULL_TREE, arg);
              return build_function_call_expr (expfn, arglist);
            }

          /* Optimize pow(sqrt(x),y) = pow(x,y*0.5).  */
          if (flag_unsafe_math_optimizations
              && (fcode == BUILT_IN_SQRT
                  || fcode == BUILT_IN_SQRTF
                  || fcode == BUILT_IN_SQRTL))
            {
              tree narg0 = TREE_VALUE (TREE_OPERAND (arg0, 1));
              tree narg1 = fold (build (MULT_EXPR, type, arg1,
                                        build_real (type, dconsthalf)));

              arglist = tree_cons (NULL_TREE, narg0,
                                   build_tree_list (NULL_TREE, narg1));
              return build_function_call_expr (fndecl, arglist);
            }

          /* Optimize pow(pow(x,y),z) = pow(x,y*z).  */
          if (flag_unsafe_math_optimizations
              && (fcode == BUILT_IN_POW
                  || fcode == BUILT_IN_POWF
                  || fcode == BUILT_IN_POWL))
            {
              tree arg00 = TREE_VALUE (TREE_OPERAND (arg0, 1));
              tree arg01 = TREE_VALUE (TREE_CHAIN (TREE_OPERAND (arg0, 1)));
              tree narg1 = fold (build (MULT_EXPR, type, arg01, arg1));
              arglist = tree_cons (NULL_TREE, arg00,
                                   build_tree_list (NULL_TREE, narg1));
              return build_function_call_expr (fndecl, arglist);
            }
        }
      break;

    case BUILT_IN_INF:
    case BUILT_IN_INFF:
    case BUILT_IN_INFL:
      return fold_builtin_inf (type, true);

    case BUILT_IN_HUGE_VAL:
    case BUILT_IN_HUGE_VALF:
    case BUILT_IN_HUGE_VALL:
      return fold_builtin_inf (type, false);

    case BUILT_IN_NAN:
    case BUILT_IN_NANF:
    case BUILT_IN_NANL:
      return fold_builtin_nan (arglist, type, true);

    case BUILT_IN_NANS:
    case BUILT_IN_NANSF:
    case BUILT_IN_NANSL:
      return fold_builtin_nan (arglist, type, false);

    case BUILT_IN_FLOOR:
    case BUILT_IN_FLOORF:
    case BUILT_IN_FLOORL:
      return fold_builtin_floor (exp);

    case BUILT_IN_CEIL:
    case BUILT_IN_CEILF:
    case BUILT_IN_CEILL:
      return fold_builtin_ceil (exp);

    case BUILT_IN_TRUNC:
    case BUILT_IN_TRUNCF:
    case BUILT_IN_TRUNCL:
      return fold_builtin_trunc (exp);

    case BUILT_IN_ROUND:
    case BUILT_IN_ROUNDF:
    case BUILT_IN_ROUNDL:
    case BUILT_IN_NEARBYINT:
    case BUILT_IN_NEARBYINTF:
    case BUILT_IN_NEARBYINTL:
      return fold_trunc_transparent_mathfn (exp);

    default:
      break;
    }

  return 0;
}

/* Conveniently construct a function call expression.  */

tree
build_function_call_expr (tree fn, tree arglist)
{
  tree call_expr;

  call_expr = build1 (ADDR_EXPR, build_pointer_type (TREE_TYPE (fn)), fn);
  call_expr = build (CALL_EXPR, TREE_TYPE (TREE_TYPE (fn)),
                     call_expr, arglist);
  TREE_SIDE_EFFECTS (call_expr) = 1;
  return fold (call_expr);
}

/* This function validates the types of a function call argument list
   represented as a tree chain of parameters against a specified list
   of tree_codes.  If the last specifier is a 0, that represents an
   ellipses, otherwise the last specifier must be a VOID_TYPE.  */

static int
validate_arglist (tree arglist, ...)
{
  enum tree_code code;
  int res = 0;
  va_list ap;

  va_start (ap, arglist);

  do
    {
      code = va_arg (ap, enum tree_code);
      switch (code)
        {
        case 0:
          /* This signifies an ellipses, any further arguments are all ok.  */
          res = 1;
          goto end;
        case VOID_TYPE:
          /* This signifies an endlink, if no arguments remain, return
             true, otherwise return false.  */
          res = arglist == 0;
          goto end;
        default:
          /* If no parameters remain or the parameter's code does not
             match the specified code, return false.  Otherwise continue
             checking any remaining arguments.  */
          if (arglist == 0
              || code != TREE_CODE (TREE_TYPE (TREE_VALUE (arglist))))
            goto end;
          break;
        }
      arglist = TREE_CHAIN (arglist);
    }
  while (1);

  /* We need gotos here since we can only have one VA_CLOSE in a
     function.  */
 end: ;
  va_end (ap);

  return res;
}

/* Default version of target-specific builtin setup that does nothing.  */

void
default_init_builtins (void)
{
}

/* Default target-specific builtin expander that does nothing.  */

rtx
default_expand_builtin (tree exp ATTRIBUTE_UNUSED,
                        rtx target ATTRIBUTE_UNUSED,
                        rtx subtarget ATTRIBUTE_UNUSED,
                        enum machine_mode mode ATTRIBUTE_UNUSED,
                        int ignore ATTRIBUTE_UNUSED)
{
  return NULL_RTX;
}

/* Instantiate all remaining CONSTANT_P_RTX nodes.  */

void
purge_builtin_constant_p (void)
{
  rtx insn, set, arg, new, note;

  for (insn = get_insns (); insn; insn = NEXT_INSN (insn))
    if (INSN_P (insn)
        && (set = single_set (insn)) != NULL_RTX
        && (GET_CODE (arg = SET_SRC (set)) == CONSTANT_P_RTX
            || (GET_CODE (arg) == SUBREG
                && (GET_CODE (arg = SUBREG_REG (arg))
                    == CONSTANT_P_RTX))))
      {
        arg = XEXP (arg, 0);
        new = CONSTANT_P (arg) ? const1_rtx : const0_rtx;
        validate_change (insn, &SET_SRC (set), new, 0);

        /* Remove the REG_EQUAL note from the insn.  */
        if ((note = find_reg_note (insn, REG_EQUAL, NULL_RTX)) != 0)
          remove_note (insn, note);
      }
}

/* Returns true is EXP represents data that would potentially reside
   in a readonly section.  */

static bool
readonly_data_expr (tree exp)
{
  STRIP_NOPS (exp);

  if (TREE_CODE (exp) == ADDR_EXPR)
    return decl_readonly_section (TREE_OPERAND (exp, 0), 0);
  else
    return false;
}