* builtins.c (fold_builtin_strncpy): Make sure len is a constant

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

/* Expand builtin functions.
   Copyright (C) 1988, 1992, 1993, 1994, 1995, 1996, 1997, 1998, 1999,
   2000, 2001, 2002, 2003, 2004 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 "tree-gimple.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"
#include "basic-block.h"

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

#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];

static int get_pointer_alignment (tree, unsigned 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_update_setjmp_buf (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_mathfn_3 (tree, rtx, rtx);
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 rtx expand_builtin_signbit (tree, rtx);
static tree fold_builtin_cabs (tree, tree);
static tree fold_builtin_trunc (tree);
static tree fold_builtin_floor (tree);
static tree fold_builtin_ceil (tree);
static tree fold_builtin_round (tree);
static tree fold_builtin_bitop (tree);
static tree fold_builtin_memcpy (tree);
static tree fold_builtin_mempcpy (tree);
static tree fold_builtin_memmove (tree);
static tree fold_builtin_strchr (tree, bool);
static tree fold_builtin_memcmp (tree);
static tree fold_builtin_strcmp (tree);
static tree fold_builtin_strncmp (tree);
static tree fold_builtin_signbit (tree);
static tree fold_builtin_copysign (tree, tree);
static tree fold_builtin_isascii (tree);
static tree fold_builtin_toascii (tree);
static tree fold_builtin_isdigit (tree);
static tree fold_builtin_fabs (tree, tree);
static tree fold_builtin_abs (tree, tree);
static tree fold_builtin_unordered_cmp (tree, enum tree_code, enum tree_code);
static tree fold_builtin_1 (tree, bool);

static tree simplify_builtin_memcmp (tree);
static tree simplify_builtin_strcmp (tree);
static tree simplify_builtin_strncmp (tree);
static tree simplify_builtin_strpbrk (tree);
static tree simplify_builtin_strstr (tree);
static tree simplify_builtin_strchr (tree);
static tree simplify_builtin_strrchr (tree);
static tree simplify_builtin_strcat (tree);
static tree simplify_builtin_strncat (tree);
static tree simplify_builtin_strspn (tree);
static tree simplify_builtin_strcspn (tree);
static void simplify_builtin_next_arg (tree);
static void simplify_builtin_va_start (tree);
static tree simplify_builtin_sprintf (tree, int);


/* 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.  */

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;
}

/* Similar to save_expr, but assumes that arbitrary code is not executed
   in between the multiple evaluations.  In particular, we assume that a
   non-addressable local variable will not be modified.  */

static tree
builtin_save_expr (tree exp)
{
  if (TREE_ADDRESSABLE (exp) == 0
      && (TREE_CODE (exp) == PARM_DECL
          || (TREE_CODE (exp) == VAR_DECL && !TREE_STATIC (exp))))
    return exp;

  return save_expr (exp);
}

/* 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 ();

  buf_addr = convert_memory_address (Pmode, buf_addr);

  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.  */

  mem = gen_rtx_MEM (Pmode, buf_addr);
  set_mem_alias_set (mem, setjmp_alias_set);
  emit_move_insn (mem, targetm.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 || !REG_P (target)
      || 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.  Use emit_jump to
     ensure that pending stack adjustments are flushed.  */
  emit_move_insn (target, const0_rtx);
  emit_jump (cont_lab);

  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 ();

  buf_addr = convert_memory_address (Pmode, buf_addr);

  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_insn (gen_rtx_CLOBBER (VOIDmode,
                                      gen_rtx_MEM (BLKmode,
                                                   gen_rtx_SCRATCH (VOIDmode))));
          emit_insn (gen_rtx_CLOBBER (VOIDmode,
                                      gen_rtx_MEM (BLKmode,
                                                   hard_frame_pointer_rtx)));

          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 (JUMP_P (insn))
        {
          REG_NOTES (insn) = alloc_EXPR_LIST (REG_NON_LOCAL_GOTO, const0_rtx,
                                              REG_NOTES (insn));
          break;
        }
      else if (CALL_P (insn))
        break;
    }
}

/* Expand a call to __builtin_nonlocal_goto.  We're passed the target label
   and the address of the save area.  */

static rtx
expand_builtin_nonlocal_goto (tree arglist)
{
  tree t_label, t_save_area;
  rtx r_label, r_save_area, r_fp, r_sp, insn;

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

  t_label = TREE_VALUE (arglist);
  arglist = TREE_CHAIN (arglist);
  t_save_area = TREE_VALUE (arglist);

  r_label = expand_expr (t_label, NULL_RTX, VOIDmode, 0);
  r_save_area = expand_expr (t_save_area, NULL_RTX, VOIDmode, 0);
  r_fp = gen_rtx_MEM (Pmode, r_save_area);
  r_sp = gen_rtx_MEM (STACK_SAVEAREA_MODE (SAVE_NONLOCAL),
                      plus_constant (r_save_area, GET_MODE_SIZE (Pmode)));

  current_function_has_nonlocal_goto = 1;

#if HAVE_nonlocal_goto
  /* ??? We no longer need to pass the static chain value, afaik.  */
  if (HAVE_nonlocal_goto)
    emit_insn (gen_nonlocal_goto (const0_rtx, r_label, r_sp, r_fp));
  else
#endif
    {
      r_label = copy_to_reg (r_label);

      emit_insn (gen_rtx_CLOBBER (VOIDmode,
                                  gen_rtx_MEM (BLKmode,
                                               gen_rtx_SCRATCH (VOIDmode))));

      emit_insn (gen_rtx_CLOBBER (VOIDmode,
                                  gen_rtx_MEM (BLKmode,
                                               hard_frame_pointer_rtx)));
 
      /* Restore frame pointer for containing function.
         This sets the actual hard register used for the frame pointer
         to the location of the function's incoming static chain info.
         The non-local goto handler will then adjust it to contain the
         proper value and reload the argument pointer, if needed.  */
      emit_move_insn (hard_frame_pointer_rtx, r_fp);
      emit_stack_restore (SAVE_NONLOCAL, r_sp, NULL_RTX);
 
      /* USE of hard_frame_pointer_rtx added for consistency;
         not clear if really needed.  */
      emit_insn (gen_rtx_USE (VOIDmode, hard_frame_pointer_rtx));
      emit_insn (gen_rtx_USE (VOIDmode, stack_pointer_rtx));
      emit_indirect_jump (r_label);
    }
 
  /* Search backwards to the jump insn and mark it as a
     non-local goto.  */
  for (insn = get_last_insn (); insn; insn = PREV_INSN (insn))
    {
      if (JUMP_P (insn))
        {
          REG_NOTES (insn) = alloc_EXPR_LIST (REG_NON_LOCAL_GOTO,
                                              const0_rtx, REG_NOTES (insn));
          break;
        }
      else if (CALL_P (insn))
        break;
    }

  return const0_rtx;
}

/* __builtin_update_setjmp_buf is passed a pointer to an array of five words
   (not all will be used on all machines) that was passed to __builtin_setjmp.
   It updates the stack pointer in that block to correspond to the current
   stack pointer.  */

static void
expand_builtin_update_setjmp_buf (rtx buf_addr)
{
  enum machine_mode sa_mode = Pmode;
  rtx stack_save;


#ifdef HAVE_save_stack_nonlocal
  if (HAVE_save_stack_nonlocal)
    sa_mode = insn_data[(int) CODE_FOR_save_stack_nonlocal].operand[0].mode;
#endif
#ifdef STACK_SAVEAREA_MODE
  sa_mode = STACK_SAVEAREA_MODE (SAVE_NONLOCAL);
#endif

  stack_save
    = gen_rtx_MEM (sa_mode,
                   memory_address
                   (sa_mode,
                    plus_constant (buf_addr, 2 * GET_MODE_SIZE (Pmode))));

#ifdef HAVE_setjmp
  if (HAVE_setjmp)
    emit_insn (gen_setjmp ());
#endif

  emit_stack_save (SAVE_NONLOCAL, &stack_save, NULL_RTX);
}

/* 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))
        {
          op0 = convert_memory_address (Pmode, op0);
          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 (!MEM_P (op0) && 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, movmemsi, ..).  */

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

  addr = convert_memory_address (Pmode, addr);

  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 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 (targetm.calls.struct_value_rtx (cfun ? TREE_TYPE (cfun->decl) : 0, 0))
        size += GET_MODE_SIZE (Pmode);

      for (regno = 0; regno < FIRST_PSEUDO_REGISTER; regno++)
        if (FUNCTION_ARG_REGNO_P (regno))
          {
            mode = reg_raw_mode[regno];

            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))
          {
            mode = reg_raw_mode[regno];

            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, tem;
  int size, align, regno;
  enum machine_mode mode;
  rtx struct_incoming_value = targetm.calls.struct_value_rtx (cfun ? TREE_TYPE (cfun->decl) : 0, 1);

  /* 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 (targetm.calls.struct_value_rtx (cfun ? TREE_TYPE (cfun->decl) : 0, 0))
    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)
      {
        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.  */
  tem = copy_to_reg (virtual_incoming_args_rtx);
#ifdef STACK_GROWS_DOWNWARD
  /* We need the pointer as the caller actually passed them to us, not
     as we might have pretended they were passed.  Make sure it's a valid
     operand, as emit_move_insn isn't expected to handle a PLUS.  */
  tem
    = force_operand (plus_constant (tem, current_function_pretend_args_size),
                     NULL_RTX);
#endif
  emit_move_insn (adjust_address (registers, Pmode, 0), tem);

  size = GET_MODE_SIZE (Pmode);

  /* Save the structure value address unless this is passed as an
     "invisible" first argument.  */
  if (struct_incoming_value)
    {
      emit_move_insn (adjust_address (registers, Pmode, size),
                      copy_to_reg (struct_incoming_value));
      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 (entry_of_function ()));
    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;
  rtx struct_value = targetm.calls.struct_value_rtx (cfun ? TREE_TYPE (cfun->decl) : 0, 0);

  arguments = convert_memory_address (Pmode, arguments);

  /* 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);

  /* Allocate a block of memory onto the stack and copy the memory
     arguments to the outgoing arguments address.  */
  allocate_dynamic_stack_space (argsize, 0, BITS_PER_UNIT);
  dest = virtual_outgoing_args_rtx;
#ifndef STACK_GROWS_DOWNWARD
  if (GET_CODE (argsize) == CONST_INT)
    dest = plus_constant (dest, -INTVAL (argsize));
  else
    dest = gen_rtx_PLUS (Pmode, dest, negate_rtx (Pmode, argsize));
#endif
  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)
    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 value = gen_reg_rtx (Pmode);
      emit_move_insn (value, adjust_address (arguments, Pmode, size));
      emit_move_insn (struct_value, value);
      if (REG_P (struct_value))
        use_reg (&call_fusage, struct_value);
      size += GET_MODE_SIZE (Pmode);
    }

  /* All arguments and registers used for the call are set up by now!  */
  function = prepare_call_address (function, NULL, &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.  */
  result = copy_addr_to_reg (XEXP (result, 0));
  return convert_memory_address (ptr_mode, result);
}

/* 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;

  result = convert_memory_address (Pmode, result);

  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_naked_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);
}

/* 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)
{
  enum built_in_function fcode, fcodef, fcodel;

  switch (fn)
    {
      CASE_MATHFN (BUILT_IN_ACOS)
      CASE_MATHFN (BUILT_IN_ACOSH)
      CASE_MATHFN (BUILT_IN_ASIN)
      CASE_MATHFN (BUILT_IN_ASINH)
      CASE_MATHFN (BUILT_IN_ATAN)
      CASE_MATHFN (BUILT_IN_ATAN2)
      CASE_MATHFN (BUILT_IN_ATANH)
      CASE_MATHFN (BUILT_IN_CBRT)
      CASE_MATHFN (BUILT_IN_CEIL)
      CASE_MATHFN (BUILT_IN_COPYSIGN)
      CASE_MATHFN (BUILT_IN_COS)
      CASE_MATHFN (BUILT_IN_COSH)
      CASE_MATHFN (BUILT_IN_DREM)
      CASE_MATHFN (BUILT_IN_ERF)
      CASE_MATHFN (BUILT_IN_ERFC)
      CASE_MATHFN (BUILT_IN_EXP)
      CASE_MATHFN (BUILT_IN_EXP10)
      CASE_MATHFN (BUILT_IN_EXP2)
      CASE_MATHFN (BUILT_IN_EXPM1)
      CASE_MATHFN (BUILT_IN_FABS)
      CASE_MATHFN (BUILT_IN_FDIM)
      CASE_MATHFN (BUILT_IN_FLOOR)
      CASE_MATHFN (BUILT_IN_FMA)
      CASE_MATHFN (BUILT_IN_FMAX)
      CASE_MATHFN (BUILT_IN_FMIN)
      CASE_MATHFN (BUILT_IN_FMOD)
      CASE_MATHFN (BUILT_IN_FREXP)
      CASE_MATHFN (BUILT_IN_GAMMA)
      CASE_MATHFN (BUILT_IN_HUGE_VAL)
      CASE_MATHFN (BUILT_IN_HYPOT)
      CASE_MATHFN (BUILT_IN_ILOGB)
      CASE_MATHFN (BUILT_IN_INF)
      CASE_MATHFN (BUILT_IN_J0)
      CASE_MATHFN (BUILT_IN_J1)
      CASE_MATHFN (BUILT_IN_JN)
      CASE_MATHFN (BUILT_IN_LDEXP)
      CASE_MATHFN (BUILT_IN_LGAMMA)
      CASE_MATHFN (BUILT_IN_LLRINT)
      CASE_MATHFN (BUILT_IN_LLROUND)
      CASE_MATHFN (BUILT_IN_LOG)
      CASE_MATHFN (BUILT_IN_LOG10)
      CASE_MATHFN (BUILT_IN_LOG1P)
      CASE_MATHFN (BUILT_IN_LOG2)
      CASE_MATHFN (BUILT_IN_LOGB)
      CASE_MATHFN (BUILT_IN_LRINT)
      CASE_MATHFN (BUILT_IN_LROUND)
      CASE_MATHFN (BUILT_IN_MODF)
      CASE_MATHFN (BUILT_IN_NAN)
      CASE_MATHFN (BUILT_IN_NANS)
      CASE_MATHFN (BUILT_IN_NEARBYINT)
      CASE_MATHFN (BUILT_IN_NEXTAFTER)
      CASE_MATHFN (BUILT_IN_NEXTTOWARD)
      CASE_MATHFN (BUILT_IN_POW)
      CASE_MATHFN (BUILT_IN_POW10)
      CASE_MATHFN (BUILT_IN_REMAINDER)
      CASE_MATHFN (BUILT_IN_REMQUO)
      CASE_MATHFN (BUILT_IN_RINT)
      CASE_MATHFN (BUILT_IN_ROUND)
      CASE_MATHFN (BUILT_IN_SCALB)
      CASE_MATHFN (BUILT_IN_SCALBLN)
      CASE_MATHFN (BUILT_IN_SCALBN)
      CASE_MATHFN (BUILT_IN_SIGNIFICAND)
      CASE_MATHFN (BUILT_IN_SIN)
      CASE_MATHFN (BUILT_IN_SINCOS)
      CASE_MATHFN (BUILT_IN_SINH)
      CASE_MATHFN (BUILT_IN_SQRT)
      CASE_MATHFN (BUILT_IN_TAN)
      CASE_MATHFN (BUILT_IN_TANH)
      CASE_MATHFN (BUILT_IN_TGAMMA)
      CASE_MATHFN (BUILT_IN_TRUNC)
      CASE_MATHFN (BUILT_IN_Y0)
      CASE_MATHFN (BUILT_IN_Y1)
      CASE_MATHFN (BUILT_IN_YN)

      default:
        return 0;
      }

  if (TYPE_MAIN_VARIANT (type) == double_type_node)
    return implicit_built_in_decls[fcode];
  else if (TYPE_MAIN_VARIANT (type) == float_type_node)
    return implicit_built_in_decls[fcodef];
  else if (TYPE_MAIN_VARIANT (type) == 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 (sqrt, exp, or log).
   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, before_call;
  tree fndecl = get_callee_fndecl (exp);
  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_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_EXP10:
    case BUILT_IN_EXP10F:
    case BUILT_IN_EXP10L:
    case BUILT_IN_POW10:
    case BUILT_IN_POW10F:
    case BUILT_IN_POW10L:
      errno_set = true; builtin_optab = exp10_optab; break;
    case BUILT_IN_EXP2:
    case BUILT_IN_EXP2F:
    case BUILT_IN_EXP2L:
      errno_set = true; builtin_optab = exp2_optab; break;
    case BUILT_IN_EXPM1:
    case BUILT_IN_EXPM1F:
    case BUILT_IN_EXPM1L:
      errno_set = true; builtin_optab = expm1_optab; break;
    case BUILT_IN_LOGB:
    case BUILT_IN_LOGBF:
    case BUILT_IN_LOGBL:
      errno_set = true; builtin_optab = logb_optab; break;
    case BUILT_IN_ILOGB:
    case BUILT_IN_ILOGBF:
    case BUILT_IN_ILOGBL:
      errno_set = true; builtin_optab = ilogb_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_LOG10:
    case BUILT_IN_LOG10F:
    case BUILT_IN_LOG10L:
      errno_set = true; builtin_optab = log10_optab; break;
    case BUILT_IN_LOG2:
    case BUILT_IN_LOG2F:
    case BUILT_IN_LOG2L:
      errno_set = true; builtin_optab = log2_optab; break;
    case BUILT_IN_LOG1P:
    case BUILT_IN_LOG1PF:
    case BUILT_IN_LOG1PL:
      errno_set = true; builtin_optab = log1p_optab; break;
    case BUILT_IN_ASIN:
    case BUILT_IN_ASINF:
    case BUILT_IN_ASINL:
      builtin_optab = asin_optab; break;
    case BUILT_IN_ACOS:
    case BUILT_IN_ACOSF:
    case BUILT_IN_ACOSL:
      builtin_optab = acos_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 = btrunc_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));

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

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

      /* 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 = builtin_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 (target != 0)
        {
          if (errno_set)
            expand_errno_check (exp, target);

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

      /* 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.  */
      end_sequence ();
    }

  before_call = get_last_insn ();

  target = expand_call (exp, target, target == const0_rtx);

  /* If this is a sqrt operation and we don't care about errno, try to
     attach a REG_EQUAL note with a SQRT rtx to the emitted libcall.
     This allows the semantics of the libcall to be visible to the RTL
     optimizers.  */
  if (builtin_optab == sqrt_optab && !errno_set)
    {
      /* Search backwards through the insns emitted by expand_call looking
         for the instruction with the REG_RETVAL note.  */
      rtx last = get_last_insn ();
      while (last != before_call)
        {
          if (find_reg_note (last, REG_RETVAL, NULL))
            {
              rtx note = find_reg_note (last, REG_EQUAL, NULL);
              /* Check that the REQ_EQUAL note is an EXPR_LIST with
                 two elements, i.e. symbol_ref(sqrt) and the operand.  */
              if (note
                  && GET_CODE (note) == EXPR_LIST
                  && GET_CODE (XEXP (note, 0)) == EXPR_LIST
                  && XEXP (XEXP (note, 0), 1) != NULL_RTX
                  && XEXP (XEXP (XEXP (note, 0), 1), 1) == NULL_RTX)
                {
                  rtx operand = XEXP (XEXP (XEXP (note, 0), 1), 0);
                  /* Check operand is a register with expected mode.  */
                  if (operand
                      && REG_P (operand)
                      && GET_MODE (operand) == mode)
                    {
                      /* Replace the REG_EQUAL note with a SQRT rtx.  */
                      rtx equiv = gen_rtx_SQRT (mode, operand);
                      set_unique_reg_note (last, REG_EQUAL, equiv);
                    }
                }
              break;
            }
          last = PREV_INSN (last);
        }
    }

  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 = get_callee_fndecl (exp);
  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;
    case BUILT_IN_FMOD:
    case BUILT_IN_FMODF:
    case BUILT_IN_FMODL:
      builtin_optab = fmod_optab; break;
    case BUILT_IN_DREM:
    case BUILT_IN_DREMF:
    case BUILT_IN_DREML:
      builtin_optab = drem_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;

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

  narg = builtin_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;
}

/* Expand a call to the builtin sin and cos math functions.
   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_3 (tree exp, rtx target, rtx subtarget)
{
  optab builtin_optab;
  rtx op0, insns, before_call;
  tree fndecl = get_callee_fndecl (exp);
  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:
    case BUILT_IN_COS:
    case BUILT_IN_COSF:
    case BUILT_IN_COSL:
      builtin_optab = sincos_optab; break;
    default:
      abort ();
    }

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

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

  /* Check if sincos insn is available, otherwise fallback
     to sin or cos insn.  */
  if (builtin_optab->handlers[(int) mode].insn_code == CODE_FOR_nothing) {
    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;
      default:
        abort();
      }
  }

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

      /* 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.  */
      if (builtin_optab == sincos_optab)
        {
          switch (DECL_FUNCTION_CODE (fndecl))
            {
            case BUILT_IN_SIN:
            case BUILT_IN_SINF:
            case BUILT_IN_SINL:
              if (!expand_twoval_unop (builtin_optab, op0, 0, target, 0))    
                abort();
              break;
            case BUILT_IN_COS:
            case BUILT_IN_COSF:
            case BUILT_IN_COSL:
              if (!expand_twoval_unop (builtin_optab, op0, target, 0, 0))
                abort();
              break;
            default:
              abort();
            }
        }
      else
        {
          target = expand_unop (mode, builtin_optab, op0, target, 0);
        }

      if (target != 0)
        {
          if (errno_set)
            expand_errno_check (exp, target);

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

      /* 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.  */
      end_sequence ();
    }

  before_call = get_last_insn ();

  target = expand_call (exp, target, target == const0_rtx);

  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);
            }
        }
    }

  if (! flag_unsafe_math_optimizations)
    return NULL_RTX;
  return expand_builtin_mathfn_2 (exp, target, subtarget);
}

/* 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
             && REG_P (result)
             && 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, tmp;
      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.  */
          tmp = fold (build2 (PLUS_EXPR, TREE_TYPE (s1), s1,
                              fold_convert (TREE_TYPE (s1),
                                            ssize_int (r - p1))));
          return expand_expr (tmp, 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;
          tree tmp;

          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.  */
          tmp = fold (build2 (PLUS_EXPR, TREE_TYPE (s1), s1,
                              fold_convert (TREE_TYPE (s1),
                                            ssize_int (r - p1))));
          return expand_expr (tmp, 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, tmp;
      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.  */
          tmp = fold (build2 (PLUS_EXPR, TREE_TYPE (s1), s1,
                              fold_convert (TREE_TYPE (s1),
                                            ssize_int (r - p1))));
          return expand_expr (tmp, 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, tmp;
      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.  */
          tmp = fold (build2 (PLUS_EXPR, TREE_TYPE (s1), s1,
                              fold_convert (TREE_TYPE (s1),
                                            ssize_int (r - p1))));
          return expand_expr (tmp, 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 (integer_zerop (len))
        {
          /* 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 SRC and DEST are the same (and not volatile), return DEST.  */
      if (operand_equal_p (src, dest, 0))
        {
          /* Evaluate and ignore LEN in case it has side-effects.  */
          expand_expr (len, 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);
          dest_mem = convert_memory_address (ptr_mode, dest_mem);
          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);
          dest_addr = convert_memory_address (ptr_mode, dest_addr);
        }
      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, call the normal function.  */
      if (dest_align == 0)
        return 0;

      /* If SRC and DEST are the same (and not volatile), do nothing.  */
      if (operand_equal_p (src, dest, 0))
        {
          tree expr;

          if (endp == 0)
            {
              /* Evaluate and ignore LEN in case it has side-effects.  */
              expand_expr (len, const0_rtx, VOIDmode, EXPAND_NORMAL);
              return expand_expr (dest, target, mode, EXPAND_NORMAL);
            }

          if (endp == 2)
            len = fold (build2 (MINUS_EXPR, TREE_TYPE (len), len,
                                integer_one_node));
          len = fold_convert (TREE_TYPE (dest), len);
          expr = fold (build2 (PLUS_EXPR, TREE_TYPE (dest), dest, len));
          return expand_expr (expr, target, mode, EXPAND_NORMAL);
        }

      /* If LEN is not constant, call the normal function.  */
      if (! 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);
          dest_mem = convert_memory_address (ptr_mode, dest_mem);
          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);
          dest_mem = convert_memory_address (ptr_mode, dest_mem);
          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 (integer_zerop (len))
        {
          /* 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 SRC and DEST are the same (and not volatile), return DEST.  */
      if (operand_equal_p (src, dest, 0))
        {
          /* Evaluate and ignore LEN in case it has side-effects.  */
          expand_expr (len, 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, fold_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);
}

#ifndef HAVE_movstr
# define HAVE_movstr 0
# define CODE_FOR_movstr CODE_FOR_nothing
#endif

/* Expand into a movstr instruction, if one is available.  Return 0 if
   we failed, the caller should emit a normal call, otherwise try to
   get the result in TARGET, if 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_movstr (tree dest, tree src, rtx target, int endp)
{
  rtx end;
  rtx dest_mem;
  rtx src_mem;
  rtx insn;
  const struct insn_data * data;

  if (!HAVE_movstr)
    return 0;

  dest_mem = get_memory_rtx (dest);
  src_mem = get_memory_rtx (src);
  if (!endp)
    {
      target = force_reg (Pmode, XEXP (dest_mem, 0));
      dest_mem = replace_equiv_address (dest_mem, target);
      end = gen_reg_rtx (Pmode);
    }
  else
    {
      if (target == 0 || target == const0_rtx)
        {
          end = gen_reg_rtx (Pmode);
          if (target == 0)
            target = end;
        }
      else
        end = target;
    }

  data = insn_data + CODE_FOR_movstr;

  if (data->operand[0].mode != VOIDmode)
    end = gen_lowpart (data->operand[0].mode, end);

  insn = data->genfun (end, dest_mem, src_mem);

  if (insn == 0)
    abort ();

  emit_insn (insn);

  /* movstr is supposed to set end to the address of the NUL
     terminator.  If the caller requested a mempcpy-like return value,
     adjust it.  */
  if (endp == 1 && target != const0_rtx)
    emit_move_insn (target, plus_constant (gen_lowpart (GET_MODE (target),
                                                        end), 1));

  return target;
}

/* 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;

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

  /* If SRC and DST are equal (and not volatile), return DST.  */
  if (operand_equal_p (src, dst, 0))
    return expand_expr (dst, target, mode, EXPAND_NORMAL);

  len = c_strlen (src, 1);
  if (len == 0 || TREE_SIDE_EFFECTS (len))
    return expand_movstr (TREE_VALUE (arglist),
                          TREE_VALUE (TREE_CHAIN (arglist)),
                          target, /*endp=*/0);

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

  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 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);
    }

  if (!validate_arglist (arglist, POINTER_TYPE, POINTER_TYPE, VOID_TYPE))
    return 0;
  else
    {
      tree dst, src, len;
      tree narglist;
      rtx ret;

      /* 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 expand_movstr (TREE_VALUE (arglist),
                              TREE_VALUE (TREE_CHAIN (arglist)),
                              target, /*endp=*/2);

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

      if (ret)
        return ret;

      if (TREE_CODE (len) == INTEGER_CST)
        {
          rtx len_rtx = expand_expr (len, NULL_RTX, VOIDmode, 0);

          if (GET_CODE (len_rtx) == CONST_INT)
            {
              ret = expand_builtin_strcpy (arglist, target, mode);

              if (ret)
                {
                  if (! target)
                    target = gen_reg_rtx (mode);
                  if (GET_MODE (target) != GET_MODE (ret))
                    ret = gen_lowpart (GET_MODE (target), ret);

                  ret = emit_move_insn (target,
                                        plus_constant (ret,
                                                       INTVAL (len_rtx)));
                  if (! ret)
                    abort ();

                  return target;
                }
            }
        }

      return expand_movstr (TREE_VALUE (arglist),
                            TREE_VALUE (TREE_CHAIN (arglist)),
                            target, /*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);
          dest_mem = convert_memory_address (ptr_mode, dest_mem);
          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 (integer_zerop (len))
        {
          /* 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);
          dest_mem = convert_memory_address (ptr_mode, dest_mem);
          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);
          dest_mem = convert_memory_address (ptr_mode, dest_mem);
          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);
          dest_addr = convert_memory_address (ptr_mode, dest_addr);
        }

      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, fold_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 (integer_zerop (len))
    {
      /* 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;
    }

  /* If both arguments are equal (and not volatile), return zero.  */
  if (operand_equal_p (arg1, arg2, 0))
    {
      /* Evaluate and ignore len in case it has side-effects.  */
      expand_expr (len, 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 (integer_onep (len))
    {
      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,
                            fold_convert (cst_uchar_ptr_node, arg1))));
      tree ind2 =
      fold (build1 (CONVERT_EXPR, integer_type_node,
                    build1 (INDIRECT_REF, cst_uchar_node,
                            fold_convert (cst_uchar_ptr_node, arg2))));
      tree result = fold (build2 (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
           && REG_P (result) && 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,
                                                TYPE_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));

  /* If both arguments are equal (and not volatile), return zero.  */
  if (operand_equal_p (arg1, arg2, 0))
    return const0_rtx;

  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,
                              fold_convert (cst_uchar_ptr_node, arg1))));
      tree ind2 =
        fold (build1 (CONVERT_EXPR, integer_type_node,
                      build1 (INDIRECT_REF, cst_uchar_node,
                              fold_convert (cst_uchar_ptr_node, arg2))));
      tree result = fold (build2 (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;
    tree fndecl;

    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
           && REG_P (result) && GET_MODE (result) == insn_mode
           && REGNO (result) >= FIRST_PSEUDO_REGISTER))
      result = gen_reg_rtx (insn_mode);

    /* Stabilize the arguments in case gen_cmpstrsi fails.  */
    arg1 = builtin_save_expr (arg1);
    arg2 = builtin_save_expr (arg2);

    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)
      {
        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;
      }

    /* Expand the library call ourselves using a stabilized argument
       list to avoid re-evaluating the function's arguments twice.  */
    arglist = build_tree_list (NULL_TREE, arg2);
    arglist = tree_cons (NULL_TREE, arg1, arglist);
    fndecl = get_callee_fndecl (exp);
    exp = build_function_call_expr (fndecl, arglist);
    return expand_call (exp, target, target == const0_rtx);
  }
#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 (integer_zerop (arg3))
    {
      /* 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;
    }

  /* If arg1 and arg2 are equal (and not volatile), return zero.  */
  if (operand_equal_p (arg1, arg2, 0))
    {
      /* Evaluate and ignore arg3 in case it has side-effects.  */
      expand_expr (arg3, 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,
                              fold_convert (cst_uchar_ptr_node, arg1))));
      tree ind2 =
        fold (build1 (CONVERT_EXPR, integer_type_node,
                      build1 (INDIRECT_REF, cst_uchar_node,
                              fold_convert (cst_uchar_ptr_node, arg2))));
      tree result = fold (build2 (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;
    tree fndecl;

    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 (build2 (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
           && REG_P (result) && GET_MODE (result) == insn_mode
           && REGNO (result) >= FIRST_PSEUDO_REGISTER))
      result = gen_reg_rtx (insn_mode);

    /* Stabilize the arguments in case gen_cmpstrsi fails.  */
    arg1 = builtin_save_expr (arg1);
    arg2 = builtin_save_expr (arg2);
    len = builtin_save_expr (len);

    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)
      {
        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;
      }

    /* Expand the library call ourselves using a stabilized argument
       list to avoid re-evaluating the function's arguments twice.  */
    arglist = build_tree_list (NULL_TREE, len);
    arglist = tree_cons (NULL_TREE, arg2, arglist);
    arglist = tree_cons (NULL_TREE, arg1, arglist);
    fndecl = get_callee_fndecl (exp);
    exp = build_function_call_expr (fndecl, arglist);
    return expand_call (exp, target, target == const0_rtx);
  }
#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 = builtin_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 (build2 (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 ();

  /* Do whatever the machine needs done in this case.  */
  val = targetm.calls.expand_builtin_saveregs ();

  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, entry_of_function ());
  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));
          valist = build_fold_addr_expr_with_type (valist, p1);
        }
    }
  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 = build_fold_indirect_ref (valist);
    }

  return valist;
}

/* The "standard" definition of va_list is void*.  */

tree
std_build_builtin_va_list (void)
{
  return ptr_type_node;
}

/* 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 = build2 (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;
  HOST_WIDE_INT boundary;

  /* Compute the rounded size of the type.  */
  align = size_int (PARM_BOUNDARY / BITS_PER_UNIT);
  alignm1 = size_int (PARM_BOUNDARY / BITS_PER_UNIT - 1);
  boundary = FUNCTION_ARG_BOUNDARY (TYPE_MODE (type), type);

  /* va_list pointer is aligned to PARM_BOUNDARY.  If argument actually
     requires greater alignment, we must perform dynamic alignment.  */

  if (boundary > PARM_BOUNDARY)
    {
      if (!PAD_VARARGS_DOWN)
        {
          t = build2 (MODIFY_EXPR, TREE_TYPE (valist), valist,
                      build2 (PLUS_EXPR, TREE_TYPE (valist), valist,
                              build_int_2 (boundary / BITS_PER_UNIT - 1, 0)));
          TREE_SIDE_EFFECTS (t) = 1;
          expand_expr (t, const0_rtx, VOIDmode, EXPAND_NORMAL);
        }
      t = build2 (MODIFY_EXPR, TREE_TYPE (valist), valist,
                  build2 (BIT_AND_EXPR, TREE_TYPE (valist), valist,
                          build_int_2 (~(boundary / BITS_PER_UNIT - 1), -1)));
      TREE_SIDE_EFFECTS (t) = 1;
      expand_expr (t, const0_rtx, VOIDmode, EXPAND_NORMAL);
    }
  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 (build2 (PLUS_EXPR, sizetype, type_size, alignm1));
      rounded_size = fold (build2 (TRUNC_DIV_EXPR, sizetype,
                                   rounded_size, align));
      rounded_size = fold (build2 (MULT_EXPR, sizetype,
                                   rounded_size, align));
    }

  /* Get AP.  */
  addr_tree = valist;
  if (PAD_VARARGS_DOWN && ! integer_zerop (rounded_size))
    {
      /* Small args are padded downward.  */
      addr_tree = fold (build2 (PLUS_EXPR, TREE_TYPE (addr_tree), addr_tree,
                                fold (build3 (COND_EXPR, sizetype,
                                              fold (build2 (GT_EXPR, sizetype,
                                                            rounded_size,
                                                            align)),
                                              size_zero_node,
                                              fold (build2 (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 = build2 (MODIFY_EXPR, TREE_TYPE (valist), valist,
                  build2 (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.  */
      inform ("if this code is reached, the program will abort");
      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
    }

  addr = convert_memory_address (Pmode, addr);

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

  return result;
}

/* Like std_expand_builtin_va_arg, but gimplify instead of expanding.  */

tree
std_gimplify_va_arg_expr (tree valist, tree type, tree *pre_p, tree *post_p)
{
  tree addr, t, type_size = NULL;
  tree align, alignm1, malign;
  tree rounded_size;
  tree valist_tmp;
  HOST_WIDE_INT boundary;

  /* Compute the rounded size of the type.  */
  align = size_int (PARM_BOUNDARY / BITS_PER_UNIT);
  alignm1 = size_int (PARM_BOUNDARY / BITS_PER_UNIT - 1);
  malign = size_int (-(PARM_BOUNDARY / BITS_PER_UNIT));
  boundary = FUNCTION_ARG_BOUNDARY (TYPE_MODE (type), type);

  valist_tmp = get_initialized_tmp_var (valist, pre_p, NULL);

  /* va_list pointer is aligned to PARM_BOUNDARY.  If argument actually
     requires greater alignment, we must perform dynamic alignment.  */

  if (boundary > PARM_BOUNDARY)
    {
      if (!PAD_VARARGS_DOWN)
        {
          t = build2 (MODIFY_EXPR, TREE_TYPE (valist), valist_tmp,
                      build2 (PLUS_EXPR, TREE_TYPE (valist), valist_tmp,
                              build_int_2 (boundary / BITS_PER_UNIT - 1, 0)));
          gimplify_and_add (t, pre_p);
        }
      t = build2 (MODIFY_EXPR, TREE_TYPE (valist), valist_tmp,
                  build2 (BIT_AND_EXPR, TREE_TYPE (valist), valist_tmp,
                          build_int_2 (~(boundary / BITS_PER_UNIT - 1), -1)));
      gimplify_and_add (t, pre_p);
    }
  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 (build2 (PLUS_EXPR, sizetype, type_size, alignm1));
      rounded_size = fold (build2 (BIT_AND_EXPR, sizetype,
                                   rounded_size, malign));
    }

  /* Reduce rounded_size so it's sharable with the postqueue.  */
  gimplify_expr (&rounded_size, pre_p, post_p, is_gimple_val, fb_rvalue);

  /* Get AP.  */
  addr = valist_tmp;
  if (PAD_VARARGS_DOWN && ! integer_zerop (rounded_size))
    {
      /* Small args are padded downward.  */
      addr = fold (build2 (PLUS_EXPR, TREE_TYPE (addr), addr,
                                fold (build3 (COND_EXPR, sizetype,
                                              fold (build2 (GT_EXPR, sizetype,
                                                            rounded_size,
                                                            align)),
                                              size_zero_node,
                                              fold (build2 (MINUS_EXPR,
                                                            sizetype,
                                                            rounded_size,
                                                            type_size))))));
    }

  /* Compute new value for AP.  */
  t = build2 (MODIFY_EXPR, TREE_TYPE (valist), valist,
              fold (build2 (PLUS_EXPR, TREE_TYPE (valist),
                            valist_tmp, rounded_size)));
  gimplify_and_add (t, pre_p);

  addr = fold_convert (build_pointer_type (type), addr);
  return build_fold_indirect_ref (addr);
}

/* Like std_gimplify_va_arg_expr, but uses pass-by-reference.  */
 
tree
ind_gimplify_va_arg_expr (tree valist, tree type, tree *pre_p, tree *post_p)
{
  tree t;
  t = build_pointer_type (type);
  t = std_gimplify_va_arg_expr (valist, t, pre_p, post_p);
  return build_fold_indirect_ref (t);
}

/* Return a dummy expression of type TYPE in order to keep going after an
   error.  */

static tree
dummy_object (tree type)
{
  tree t = convert (build_pointer_type (type), null_pointer_node);
  return build1 (INDIRECT_REF, type, t);
}

/* Like expand_builtin_va_arg, but gimplify instead of expanding.  */

enum gimplify_status
gimplify_va_arg_expr (tree *expr_p, tree *pre_p, tree *post_p)
{
  tree promoted_type, want_va_type, have_va_type;
  tree valist = TREE_OPERAND (*expr_p, 0);
  tree type = TREE_TYPE (*expr_p);
  tree t;

  /* Verify that valist is of the proper type.  */
  want_va_type = va_list_type_node;
  have_va_type = TREE_TYPE (valist);

  if (have_va_type == error_mark_node)
    return GS_ERROR;

  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'");
      return GS_ERROR;
    }

  /* 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)
    {
      static bool gave_help;

      /* 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 ("`%T' is promoted to `%T' when passed through `...'",
               type, promoted_type);
      if (! gave_help)
        {
          gave_help = true;
          warning ("(so you should pass `%T' not `%T' to `va_arg')",
                   promoted_type, type);
        }

      /* We can, however, treat "undefined" any way we please.
         Call abort to encourage the user to fix the program.  */
      inform ("if this code is reached, the program will abort");
      t = build_function_call_expr (implicit_built_in_decls[BUILT_IN_TRAP],
                                    NULL);
      append_to_statement_list (t, pre_p);

      /* This is dead code, but go ahead and finish so that the
         mode of the result comes out right.  */
      *expr_p = dummy_object (type);
      return GS_ALL_DONE;
    }
  else
    {
      /* Make it easier for the backends by protecting the valist argument
         from multiple evaluations.  */
      if (TREE_CODE (va_list_type_node) == ARRAY_TYPE)
        {
          /* 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));
              valist = build_fold_addr_expr_with_type (valist, p1);
            }
          gimplify_expr (&valist, pre_p, post_p, is_gimple_val, fb_rvalue);
        }
      else
        gimplify_expr (&valist, pre_p, post_p, is_gimple_min_lval, fb_lvalue);

      if (!targetm.calls.gimplify_va_arg_expr)
        /* Once most targets are converted this should abort.  */
        return GS_ALL_DONE;

      *expr_p = targetm.calls.gimplify_va_arg_expr (valist, type, pre_p, post_p);
      return GS_OK;
    }
}

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

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

  /* 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);

  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 = build2 (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);

      dstb = convert_memory_address (Pmode, dstb);
      srcb = convert_memory_address (Pmode, srcb);

      /* "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 (!REG_P (tem)
          && ! 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;

  /* In -fmudflap-instrumented code, alloca() and __builtin_alloca()
     should always expand to function calls.  These can be intercepted
     in libmudflap.  */
  if (flag_mudflap)
    return 0;

  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);
  result = convert_memory_address (ptr_mode, result);

  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;
          }
      }
      /* Fall through.  */
    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)))
    {
      rtx insn, drop_through_label, temp;

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

      drop_through_label = get_last_insn ();
      if (drop_through_label && NOTE_P (drop_through_label))
        drop_through_label = prev_nonnote_insn (drop_through_label);
      if (drop_through_label && !LABEL_P (drop_through_label))
        drop_through_label = NULL_RTX;
      end_sequence ();

      if (! if_true_label)
        if_true_label = drop_through_label;
      if (! if_false_label)
        if_false_label = drop_through_label;

      /* Go through and add the expect's to each of the conditional jumps.  */
      insn = ret;
      while (insn != NULL_RTX)
        {
          rtx next = NEXT_INSN (insn);

          if (JUMP_P (insn) && any_condjump_p (insn))
            {
              rtx ifelse = SET_SRC (pc_set (insn));
              rtx then_dest = XEXP (ifelse, 1);
              rtx else_dest = XEXP (ifelse, 2);
              int taken = -1;

              /* First check if we recognize any of the labels.  */
              if (GET_CODE (then_dest) == LABEL_REF
                  && XEXP (then_dest, 0) == if_true_label)
                taken = 1;
              else if (GET_CODE (then_dest) == LABEL_REF
                       && XEXP (then_dest, 0) == if_false_label)
                taken = 0;
              else if (GET_CODE (else_dest) == LABEL_REF
                       && XEXP (else_dest, 0) == if_false_label)
                taken = 1;
              else if (GET_CODE (else_dest) == LABEL_REF
                       && XEXP (else_dest, 0) == if_true_label)
                taken = 0;
              /* Otherwise check where we drop through.  */
              else if (else_dest == pc_rtx)
                {
                  if (next && NOTE_P (next))
                    next = next_nonnote_insn (next);

                  if (next && JUMP_P (next)
                      && any_uncondjump_p (next))
                    temp = XEXP (SET_SRC (pc_set (next)), 0);
                  else
                    temp = next;

                  /* TEMP is either a CODE_LABEL, NULL_RTX or something
                     else that can't possibly match either target label.  */
                  if (temp == if_false_label)
                    taken = 1;
                  else if (temp == if_true_label)
                    taken = 0;
                }
              else if (then_dest == pc_rtx)
                {
                  if (next && NOTE_P (next))
                    next = next_nonnote_insn (next);

                  if (next && JUMP_P (next)
                      && any_uncondjump_p (next))
                    temp = XEXP (SET_SRC (pc_set (next)), 0);
                  else
                    temp = next;

                  if (temp == if_false_label)
                    taken = 0;
                  else if (temp == if_true_label)
                    taken = 1;
                }

              if (taken != -1)
                {
                  /* If the test is expected to fail, reverse the
                     probabilities.  */
                  if (integer_zerop (arg1))
                    taken = 1 - taken;
                  predict_insn_def (insn, PRED_BUILTIN_EXPECT, taken);
                }
            }

          insn = next;
        }
    }

  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_INVARIANT (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-terminated string that's one char shorter
                 than the original, stripping off the trailing '\n'.  */
              char *newstr = 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_convert (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;
}

/* Expand a call to either the entry or exit function profiler.  */

static rtx
expand_builtin_profile_func (bool exitp)
{
  rtx this, which;

  this = DECL_RTL (current_function_decl);
  if (MEM_P (this))
    this = XEXP (this, 0);
  else
    abort ();

  if (exitp)
    which = profile_function_exit_libfunc;
  else
    which = profile_function_entry_libfunc;

  emit_library_call (which, LCT_NORMAL, VOIDmode, 2, this, Pmode,
                     expand_builtin_return_addr (BUILT_IN_RETURN_ADDRESS,
                                                 0, hard_frame_pointer_rtx),
                     Pmode);

  return const0_rtx;
}

/* Given a trampoline address, make sure it satisfies TRAMPOLINE_ALIGNMENT.  */

static rtx
round_trampoline_addr (rtx tramp)
{
  rtx temp, addend, mask;

  /* If we don't need too much alignment, we'll have been guaranteed
     proper alignment by get_trampoline_type.  */
  if (TRAMPOLINE_ALIGNMENT <= STACK_BOUNDARY)
    return tramp;

  /* Round address up to desired boundary.  */
  temp = gen_reg_rtx (Pmode);
  addend = GEN_INT (TRAMPOLINE_ALIGNMENT / BITS_PER_UNIT - 1);
  mask = GEN_INT (-TRAMPOLINE_ALIGNMENT / BITS_PER_UNIT);

  temp  = expand_simple_binop (Pmode, PLUS, tramp, addend,
                               temp, 0, OPTAB_LIB_WIDEN);
  tramp = expand_simple_binop (Pmode, AND, temp, mask,
                               temp, 0, OPTAB_LIB_WIDEN);

  return tramp;
}

static rtx
expand_builtin_init_trampoline (tree arglist)
{
  tree t_tramp, t_func, t_chain;
  rtx r_tramp, r_func, r_chain;
#ifdef TRAMPOLINE_TEMPLATE
  rtx blktramp;
#endif

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

  t_tramp = TREE_VALUE (arglist);
  arglist = TREE_CHAIN (arglist);
  t_func = TREE_VALUE (arglist);
  arglist = TREE_CHAIN (arglist);
  t_chain = TREE_VALUE (arglist);

  r_tramp = expand_expr (t_tramp, NULL_RTX, VOIDmode, 0);
  r_func = expand_expr (t_func, NULL_RTX, VOIDmode, 0);
  r_chain = expand_expr (t_chain, NULL_RTX, VOIDmode, 0);

  /* Generate insns to initialize the trampoline.  */
  r_tramp = round_trampoline_addr (r_tramp);
#ifdef TRAMPOLINE_TEMPLATE
  blktramp = gen_rtx_MEM (BLKmode, r_tramp);
  set_mem_align (blktramp, TRAMPOLINE_ALIGNMENT);
  emit_block_move (blktramp, assemble_trampoline_template (),
                   GEN_INT (TRAMPOLINE_SIZE), BLOCK_OP_NORMAL);
#endif
  trampolines_created = 1;
  INITIALIZE_TRAMPOLINE (r_tramp, r_func, r_chain);

  return const0_rtx;
}

static rtx
expand_builtin_adjust_trampoline (tree arglist)
{
  rtx tramp;

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

  tramp = expand_expr (TREE_VALUE (arglist), NULL_RTX, VOIDmode, 0);
  tramp = round_trampoline_addr (tramp);
#ifdef TRAMPOLINE_ADJUST_ADDRESS
  TRAMPOLINE_ADJUST_ADDRESS (tramp);
#endif

  return tramp;
}

/* Expand a call to the built-in signbit, signbitf or signbitl function.
   Return NULL_RTX 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_signbit (tree exp, rtx target)
{
  const struct real_format *fmt;
  enum machine_mode fmode, imode, rmode;
  HOST_WIDE_INT hi, lo;
  tree arg, arglist;
  int bitpos;
  rtx temp;

  arglist = TREE_OPERAND (exp, 1);
  if (!validate_arglist (arglist, REAL_TYPE, VOID_TYPE))
    return 0;

  arg = TREE_VALUE (arglist);
  fmode = TYPE_MODE (TREE_TYPE (arg));
  rmode = TYPE_MODE (TREE_TYPE (exp));
  fmt = REAL_MODE_FORMAT (fmode);

  /* For floating point formats without a sign bit, implement signbit
     as "ARG < 0.0".  */
  if (fmt->signbit < 0)
  {
    /* But we can't do this if the format supports signed zero.  */
    if (fmt->has_signed_zero && HONOR_SIGNED_ZEROS (fmode))
      return 0;

    arg = fold (build2 (LT_EXPR, TREE_TYPE (exp), arg,
                        build_real (TREE_TYPE (arg), dconst0)));
    return expand_expr (arg, target, VOIDmode, EXPAND_NORMAL);
  }

  imode = int_mode_for_mode (fmode);
  if (imode == BLKmode)
    return 0;

  bitpos = fmt->signbit;
  /* Handle targets with different FP word orders.  */
  if (FLOAT_WORDS_BIG_ENDIAN != WORDS_BIG_ENDIAN)
    {
      int nwords = GET_MODE_BITSIZE (fmode) / BITS_PER_WORD;
      int word = nwords - (bitpos / BITS_PER_WORD) - 1;
      bitpos = word * BITS_PER_WORD + bitpos % BITS_PER_WORD;
    }

  /* If the sign bit is not in the lowpart and the floating point format
     is wider than an integer, check that is twice the size of an integer
     so that we can use gen_highpart below.  */
  if (bitpos >= GET_MODE_BITSIZE (rmode)
      && GET_MODE_BITSIZE (imode) != 2 * GET_MODE_BITSIZE (rmode))
    return 0;

  temp = expand_expr (arg, NULL_RTX, VOIDmode, 0);
  temp = gen_lowpart (imode, temp);

  if (GET_MODE_BITSIZE (imode) > GET_MODE_BITSIZE (rmode))
    {
      if (BYTES_BIG_ENDIAN)
        bitpos = GET_MODE_BITSIZE (imode) - 1 - bitpos;
      temp = copy_to_mode_reg (imode, temp);
      temp = extract_bit_field (temp, 1, bitpos, 1,
                                NULL_RTX, rmode, rmode,
                                GET_MODE_SIZE (imode));
    }
  else
    {
      if (GET_MODE_BITSIZE (imode) < GET_MODE_BITSIZE (rmode))
        temp = gen_lowpart (rmode, temp);
      if (bitpos < HOST_BITS_PER_WIDE_INT)
        {
          hi = 0;
          lo = (HOST_WIDE_INT) 1 << bitpos;
        }
      else
        {
          hi = (HOST_WIDE_INT) 1 << (bitpos - HOST_BITS_PER_WIDE_INT);
          lo = 0;
        }

      temp = force_reg (rmode, temp);
      temp = expand_binop (rmode, and_optab, temp,
                           immed_double_const (lo, hi, rmode),
                           target, 1, OPTAB_LIB_WIDEN);
    }
  return temp;
}

/* Expand fork or exec calls.  TARGET is the desired target of the
   call.  ARGLIST is the list of arguments of the call.  FN is the
   identificator of the actual function.  IGNORE is nonzero if the
   value is to be ignored.  */

static rtx
expand_builtin_fork_or_exec (tree fn, tree arglist, rtx target, int ignore)
{
  tree id, decl;
  tree call;

  /* If we are not profiling, just call the function.  */
  if (!profile_arc_flag)
    return NULL_RTX;

  /* Otherwise call the wrapper.  This should be equivalent for the rest of
     compiler, so the code does not diverge, and the wrapper may run the
     code necessary for keeping the profiling sane.  */

  switch (DECL_FUNCTION_CODE (fn))
    {
    case BUILT_IN_FORK:
      id = get_identifier ("__gcov_fork");
      break;

    case BUILT_IN_EXECL:
      id = get_identifier ("__gcov_execl");
      break;

    case BUILT_IN_EXECV:
      id = get_identifier ("__gcov_execv");
      break;

    case BUILT_IN_EXECLP:
      id = get_identifier ("__gcov_execlp");
      break;

    case BUILT_IN_EXECLE:
      id = get_identifier ("__gcov_execle");
      break;

    case BUILT_IN_EXECVP:
      id = get_identifier ("__gcov_execvp");
      break;

    case BUILT_IN_EXECVE:
      id = get_identifier ("__gcov_execve");
      break;

    default:
      abort ();
    }

  decl = build_decl (FUNCTION_DECL, id, TREE_TYPE (fn));
  DECL_EXTERNAL (decl) = 1;
  TREE_PUBLIC (decl) = 1;
  DECL_ARTIFICIAL (decl) = 1;
  TREE_NOTHROW (decl) = 1;
  call = build_function_call_expr (decl, arglist);

  return expand_call (call, target, ignore);
}
\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 = get_callee_fndecl (exp);
  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_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_EXP:
    case BUILT_IN_EXPF:
    case BUILT_IN_EXPL:
    case BUILT_IN_EXP10:
    case BUILT_IN_EXP10F:
    case BUILT_IN_EXP10L:
    case BUILT_IN_POW10:
    case BUILT_IN_POW10F:
    case BUILT_IN_POW10L:
    case BUILT_IN_EXP2:
    case BUILT_IN_EXP2F:
    case BUILT_IN_EXP2L:
    case BUILT_IN_EXPM1:
    case BUILT_IN_EXPM1F:
    case BUILT_IN_EXPM1L:
    case BUILT_IN_LOGB:
    case BUILT_IN_LOGBF:
    case BUILT_IN_LOGBL:
    case BUILT_IN_ILOGB:
    case BUILT_IN_ILOGBF:
    case BUILT_IN_ILOGBL:
    case BUILT_IN_LOG:
    case BUILT_IN_LOGF:
    case BUILT_IN_LOGL:
    case BUILT_IN_LOG10:
    case BUILT_IN_LOG10F:
    case BUILT_IN_LOG10L:
    case BUILT_IN_LOG2:
    case BUILT_IN_LOG2F:
    case BUILT_IN_LOG2L:
    case BUILT_IN_LOG1P:
    case BUILT_IN_LOG1PF:
    case BUILT_IN_LOG1PL:
    case BUILT_IN_TAN:
    case BUILT_IN_TANF:
    case BUILT_IN_TANL:
    case BUILT_IN_ASIN:
    case BUILT_IN_ASINF:
    case BUILT_IN_ASINL:
    case BUILT_IN_ACOS:
    case BUILT_IN_ACOSF:
    case BUILT_IN_ACOSL:
    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:
      target = expand_builtin_pow (exp, target, subtarget);
      if (target)
        return target;
      break;

    case BUILT_IN_ATAN2:
    case BUILT_IN_ATAN2F:
    case BUILT_IN_ATAN2L:
    case BUILT_IN_FMOD:
    case BUILT_IN_FMODF:
    case BUILT_IN_FMODL:
    case BUILT_IN_DREM:
    case BUILT_IN_DREMF:
    case BUILT_IN_DREML:
      if (! flag_unsafe_math_optimizations)
        break;
      target = expand_builtin_mathfn_2 (exp, target, subtarget);
      if (target)
        return target;
      break;

    case BUILT_IN_SIN:
    case BUILT_IN_SINF:
    case BUILT_IN_SINL:
    case BUILT_IN_COS:
    case BUILT_IN_COSF:
    case BUILT_IN_COSL:
      if (! flag_unsafe_math_optimizations)
        break;
      target = expand_builtin_mathfn_3 (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:
      simplify_builtin_next_arg (arglist);
      return expand_builtin_next_arg (arglist);

    case BUILT_IN_CLASSIFY_TYPE:
      return expand_builtin_classify_type (arglist);

    case BUILT_IN_CONSTANT_P:
      return const0_rtx;

    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)))
          || !MEM_P (DECL_RTL (DECL_RESULT (current_function_decl))))
        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_STACK_ALLOC:
      expand_stack_alloc (TREE_VALUE (arglist),
                          TREE_VALUE (TREE_CHAIN (arglist)));
      return const0_rtx;

    case BUILT_IN_STACK_SAVE:
      return expand_stack_save ();

    case BUILT_IN_STACK_RESTORE:
      expand_stack_restore (TREE_VALUE (arglist));
      return const0_rtx;

    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_NONLOCAL_GOTO:
      target = expand_builtin_nonlocal_goto (arglist);
      if (target)
        return target;
      break;

      /* This updates the setjmp buffer that is its argument with the value
         of the current stack pointer.  */
    case BUILT_IN_UPDATE_SETJMP_BUF:
      if (validate_arglist (arglist, POINTER_TYPE, VOID_TYPE))
        {
          rtx buf_addr
            = expand_expr (TREE_VALUE (arglist), NULL_RTX, VOIDmode, 0);

          expand_builtin_update_setjmp_buf (buf_addr);
          return const0_rtx;
        }
      break;

    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;

    case BUILT_IN_SIGNBIT:
    case BUILT_IN_SIGNBITF:
    case BUILT_IN_SIGNBITL:
      target = expand_builtin_signbit (exp, target);
      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_EXTEND_POINTER:
      return expand_builtin_extend_pointer (TREE_VALUE (arglist));

    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;

    case BUILT_IN_PROFILE_FUNC_ENTER:
      return expand_builtin_profile_func (false);
    case BUILT_IN_PROFILE_FUNC_EXIT:
      return expand_builtin_profile_func (true);

    case BUILT_IN_INIT_TRAMPOLINE:
      return expand_builtin_init_trampoline (arglist);
    case BUILT_IN_ADJUST_TRAMPOLINE:
      return expand_builtin_adjust_trampoline (arglist);

    case BUILT_IN_FORK:
    case BUILT_IN_EXECL:
    case BUILT_IN_EXECV:
    case BUILT_IN_EXECLP:
    case BUILT_IN_EXECLE:
    case BUILT_IN_EXECVP:
    case BUILT_IN_EXECVE:
      target = expand_builtin_fork_or_exec (fndecl, arglist, target, ignore);
      if (target)
        return target;
      break;

    default:    /* just do library call, if unknown builtin */
      break;
    }

  /* 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
   function.  If the tree T is a call to a built-in function with
   the right number of arguments of the appropriate types, return
   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, parmlist;
  tree argtype, parmtype;

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

  fndecl = get_callee_fndecl (t);
  if (fndecl == NULL_TREE
      || 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);
  parmlist = TYPE_ARG_TYPES (TREE_TYPE (fndecl));
  for (; parmlist; parmlist = TREE_CHAIN (parmlist))
    {
      /* If a function doesn't take a variable number of arguments,
         the last element in the list will have type `void'.  */
      parmtype = TREE_VALUE (parmlist);
      if (VOID_TYPE_P (parmtype))
        {
          if (arglist)
            return END_BUILTINS;
          return DECL_FUNCTION_CODE (fndecl);
        }

      if (! arglist)
        return END_BUILTINS;

      argtype = TREE_TYPE (TREE_VALUE (arglist));

      if (SCALAR_FLOAT_TYPE_P (parmtype))
        {
          if (! SCALAR_FLOAT_TYPE_P (argtype))
            return END_BUILTINS;
        }
      else if (COMPLEX_FLOAT_TYPE_P (parmtype))
        {
          if (! COMPLEX_FLOAT_TYPE_P (argtype))
            return END_BUILTINS;
        }
      else if (POINTER_TYPE_P (parmtype))
        {
          if (! POINTER_TYPE_P (argtype))
            return END_BUILTINS;
        }
      else if (INTEGRAL_TYPE_P (parmtype))
        {
          if (! INTEGRAL_TYPE_P (argtype))
            return END_BUILTINS;
        }
      else
        return END_BUILTINS;

      arglist = TREE_CHAIN (arglist);
    }

  /* Variable-length argument list.  */
  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 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)
      || 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_expect, if we expect that a comparison against
   the argument will fold to a constant.  In practice, this means a true
   constant or the address of a non-weak symbol.  ARGLIST is the argument
   list of the call.  */

static tree
fold_builtin_expect (tree arglist)
{
  tree arg, inner;

  if (arglist == 0)
    return 0;

  arg = TREE_VALUE (arglist);

  /* If the argument isn't invariant, then there's nothing we can do.  */
  if (!TREE_INVARIANT (arg))
    return 0;

  /* If we're looking at an address of a weak decl, then do not fold.  */
  inner = arg;
  STRIP_NOPS (inner);
  if (TREE_CODE (inner) == ADDR_EXPR)
    {
      do
        {
          inner = TREE_OPERAND (inner, 0);
        }
      while (TREE_CODE (inner) == COMPONENT_REF
             || TREE_CODE (inner) == ARRAY_REF);
      if (DECL_P (inner) && DECL_WEAK (inner))
        return 0;
    }

  /* Otherwise, ARG already has the proper type for the return value.  */
  return arg;
}

/* 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_RINT:
        case BUILT_IN_RINTF:
        case BUILT_IN_RINTL:
        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 = get_callee_fndecl (exp);
  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 fold_convert (ftype,
                               build_function_call_expr (decl, arglist));
        }
    }
  return 0;
}

/* EXP is assumed to be builtin call which can narrow the FP type of
   the argument, for instance lround((double)f) -> lroundf (f).  */

static tree
fold_fixed_mathfn (tree exp)
{
  tree fndecl = get_callee_fndecl (exp);
  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);

  /* 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 fold (build1 (FIX_TRUNC_EXPR, TREE_TYPE (exp), arg));

  if (optimize)
    {
      tree ftype = TREE_TYPE (arg);
      tree arg0 = strip_float_extensions (arg);
      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 build_function_call_expr (decl, arglist);
        }
    }
  return 0;
}

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

static tree
fold_builtin_cabs (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)
    {
      tree sqrtfn = mathfn_built_in (type, BUILT_IN_SQRT);

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

          arg = builtin_save_expr (arg);

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

          rpart = builtin_save_expr (rpart);
          ipart = builtin_save_expr (ipart);

          result = fold (build2 (PLUS_EXPR, type,
                                 fold (build2 (MULT_EXPR, type,
                                               rpart, rpart)),
                                 fold (build2 (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);
}

/* Fold function call to builtin round, roundf or roundl.  Return
   NULL_TREE if no simplification can be made.  */

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

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

  /* Optimize round 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_round (&r, TYPE_MODE (type), &x);
          return build_real (type, r);
        }
    }

  return fold_trunc_transparent_mathfn (exp);
}

/* Fold function call to builtin lround, lroundf or lroundl (or the
   corresponding long long versions).  Return NULL_TREE if no
   simplification can be made.  */

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

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

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

      if (! REAL_VALUE_ISNAN (x) && ! REAL_VALUE_ISINF (x))
        {
          tree itype = TREE_TYPE (exp), ftype = TREE_TYPE (arg), result;
          HOST_WIDE_INT hi, lo;
          REAL_VALUE_TYPE r;

          real_round (&r, TYPE_MODE (ftype), &x);
          REAL_VALUE_TO_INT (&lo, &hi, r);
          result = build_int_2 (lo, hi);
          if (int_fits_type_p (result, itype))
            return fold_convert (itype, result);
        }
    }

  return fold_fixed_mathfn (exp);
}

/* Fold function call to builtin ffs, clz, ctz, popcount and parity
   and their long and long long variants (i.e. ffsl and ffsll).
   Return NULL_TREE if no simplification can be made.  */

static tree
fold_builtin_bitop (tree exp)
{
  tree fndecl = get_callee_fndecl (exp);
  tree arglist = TREE_OPERAND (exp, 1);
  tree arg;

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

  /* Optimize for constant argument.  */
  arg = TREE_VALUE (arglist);
  if (TREE_CODE (arg) == INTEGER_CST && ! TREE_CONSTANT_OVERFLOW (arg))
    {
      HOST_WIDE_INT hi, width, result;
      unsigned HOST_WIDE_INT lo;
      tree type, t;

      type = TREE_TYPE (arg);
      width = TYPE_PRECISION (type);
      lo = TREE_INT_CST_LOW (arg);

      /* Clear all the bits that are beyond the type's precision.  */
      if (width > HOST_BITS_PER_WIDE_INT)
        {
          hi = TREE_INT_CST_HIGH (arg);
          if (width < 2 * HOST_BITS_PER_WIDE_INT)
            hi &= ~((HOST_WIDE_INT) (-1) >> (width - HOST_BITS_PER_WIDE_INT));
        }
      else
        {
          hi = 0;
          if (width < HOST_BITS_PER_WIDE_INT)
            lo &= ~((unsigned HOST_WIDE_INT) (-1) << width);
        }

      switch (DECL_FUNCTION_CODE (fndecl))
        {
        case BUILT_IN_FFS:
        case BUILT_IN_FFSL:
        case BUILT_IN_FFSLL:
          if (lo != 0)
            result = exact_log2 (lo & -lo) + 1;
          else if (hi != 0)
            result = HOST_BITS_PER_WIDE_INT + exact_log2 (hi & -hi) + 1;
          else
            result = 0;
          break;

        case BUILT_IN_CLZ:
        case BUILT_IN_CLZL:
        case BUILT_IN_CLZLL:
          if (hi != 0)
            result = width - floor_log2 (hi) - 1 - HOST_BITS_PER_WIDE_INT;
          else if (lo != 0)
            result = width - floor_log2 (lo) - 1;
          else if (! CLZ_DEFINED_VALUE_AT_ZERO (TYPE_MODE (type), result))
            result = width;
          break;

        case BUILT_IN_CTZ:
        case BUILT_IN_CTZL:
        case BUILT_IN_CTZLL:
          if (lo != 0)
            result = exact_log2 (lo & -lo);
          else if (hi != 0)
            result = HOST_BITS_PER_WIDE_INT + exact_log2 (hi & -hi);
          else if (! CTZ_DEFINED_VALUE_AT_ZERO (TYPE_MODE (type), result))
            result = width;
          break;

        case BUILT_IN_POPCOUNT:
        case BUILT_IN_POPCOUNTL:
        case BUILT_IN_POPCOUNTLL:
          result = 0;
          while (lo)
            result++, lo &= lo - 1;
          while (hi)
            result++, hi &= hi - 1;
          break;

        case BUILT_IN_PARITY:
        case BUILT_IN_PARITYL:
        case BUILT_IN_PARITYLL:
          result = 0;
          while (lo)
            result++, lo &= lo - 1;
          while (hi)
            result++, hi &= hi - 1;
          result &= 1;
          break;

        default:
          abort();
        }

      t = build_int_2 (result, 0);
      TREE_TYPE (t) = TREE_TYPE (exp);
      return t;
    }

  return NULL_TREE;
}

/* Return true if EXPR is the real constant contained in VALUE.  */

static bool
real_dconstp (tree expr, const REAL_VALUE_TYPE *value)
{
  STRIP_NOPS (expr);

  return ((TREE_CODE (expr) == REAL_CST
           && ! TREE_CONSTANT_OVERFLOW (expr)
           && REAL_VALUES_EQUAL (TREE_REAL_CST (expr), *value))
          || (TREE_CODE (expr) == COMPLEX_CST
              && real_dconstp (TREE_REALPART (expr), value)
              && real_zerop (TREE_IMAGPART (expr))));
}

/* A subroutine of fold_builtin to fold the various logarithmic
   functions.  EXP is the CALL_EXPR of a call to a builtin logN
   function.  VALUE is the base of the logN function.  */

static tree
fold_builtin_logarithm (tree exp, const REAL_VALUE_TYPE *value)
{
  tree arglist = TREE_OPERAND (exp, 1);

  if (validate_arglist (arglist, REAL_TYPE, VOID_TYPE))
    {
      tree fndecl = get_callee_fndecl (exp);
      tree type = TREE_TYPE (TREE_TYPE (fndecl));
      tree arg = TREE_VALUE (arglist);
      const enum built_in_function fcode = builtin_mathfn_code (arg);

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

      /* Optimize logN(N) = 1.0.  If N can't be truncated to MODE
         exactly, then only do this if flag_unsafe_math_optimizations.  */
      if (exact_real_truncate (TYPE_MODE (type), value)
          || flag_unsafe_math_optimizations)
        {
          const REAL_VALUE_TYPE value_truncate =
            real_value_truncate (TYPE_MODE (type), *value);
          if (real_dconstp (arg, &value_truncate))
            return build_real (type, dconst1);
        }

      /* Special case, optimize logN(expN(x)) = x.  */
      if (flag_unsafe_math_optimizations
          && ((value == &dconste
               && (fcode == BUILT_IN_EXP
                   || fcode == BUILT_IN_EXPF
                   || fcode == BUILT_IN_EXPL))
              || (value == &dconst2
                  && (fcode == BUILT_IN_EXP2
                      || fcode == BUILT_IN_EXP2F
                      || fcode == BUILT_IN_EXP2L))
              || (value == &dconst10 && (BUILTIN_EXP10_P (fcode)))))
        return fold_convert (type, TREE_VALUE (TREE_OPERAND (arg, 1)));

      /* Optimize logN(func()) for various exponential functions.  We
         want to determine the value "x" and the power "exponent" in
         order to transform logN(x**exponent) into exponent*logN(x).  */
      if (flag_unsafe_math_optimizations)
        {
          tree exponent = 0, x = 0;

          switch (fcode)
          {
          case BUILT_IN_EXP:
          case BUILT_IN_EXPF:
          case BUILT_IN_EXPL:
            /* Prepare to do logN(exp(exponent) -> exponent*logN(e).  */
            x = build_real (type,
                            real_value_truncate (TYPE_MODE (type), dconste));
            exponent = TREE_VALUE (TREE_OPERAND (arg, 1));
            break;
          case BUILT_IN_EXP2:
          case BUILT_IN_EXP2F:
          case BUILT_IN_EXP2L:
            /* Prepare to do logN(exp2(exponent) -> exponent*logN(2).  */
            x = build_real (type, dconst2);
            exponent = TREE_VALUE (TREE_OPERAND (arg, 1));
            break;
          case BUILT_IN_EXP10:
          case BUILT_IN_EXP10F:
          case BUILT_IN_EXP10L:
          case BUILT_IN_POW10:
          case BUILT_IN_POW10F:
          case BUILT_IN_POW10L:
            /* Prepare to do logN(exp10(exponent) -> exponent*logN(10).  */
            x = build_real (type, dconst10);
            exponent = TREE_VALUE (TREE_OPERAND (arg, 1));
            break;
          case BUILT_IN_SQRT:
          case BUILT_IN_SQRTF:
          case BUILT_IN_SQRTL:
            /* Prepare to do logN(sqrt(x) -> 0.5*logN(x).  */
            x = TREE_VALUE (TREE_OPERAND (arg, 1));
            exponent = build_real (type, dconsthalf);
            break;
          case BUILT_IN_CBRT:
          case BUILT_IN_CBRTF:
          case BUILT_IN_CBRTL:
            /* Prepare to do logN(cbrt(x) -> (1/3)*logN(x).  */
            x = TREE_VALUE (TREE_OPERAND (arg, 1));
            exponent = build_real (type, real_value_truncate (TYPE_MODE (type),
                                                              dconstthird));
            break;
          case BUILT_IN_POW:
          case BUILT_IN_POWF:
          case BUILT_IN_POWL:
            /* Prepare to do logN(pow(x,exponent) -> exponent*logN(x).  */
            x = TREE_VALUE (TREE_OPERAND (arg, 1));
            exponent = TREE_VALUE (TREE_CHAIN (TREE_OPERAND (arg, 1)));
            break;
          default:
            break;
          }

          /* Now perform the optimization.  */
          if (x && exponent)
            {
              tree logfn;
              arglist = build_tree_list (NULL_TREE, x);
              logfn = build_function_call_expr (fndecl, arglist);
              return fold (build2 (MULT_EXPR, type, exponent, logfn));
            }
        }
    }

  return 0;
}

/* A subroutine of fold_builtin to fold the various exponent
   functions.  EXP is the CALL_EXPR of a call to a builtin function.
   VALUE is the value which will be raised to a power.  */

static tree
fold_builtin_exponent (tree exp, const REAL_VALUE_TYPE *value)
{
  tree arglist = TREE_OPERAND (exp, 1);

  if (validate_arglist (arglist, REAL_TYPE, VOID_TYPE))
    {
      tree fndecl = get_callee_fndecl (exp);
      tree type = TREE_TYPE (TREE_TYPE (fndecl));
      tree arg = TREE_VALUE (arglist);

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

      /* Optimize expN(1.0) = N.  */
      if (real_onep (arg))
        {
          REAL_VALUE_TYPE cst;

          real_convert (&cst, TYPE_MODE (type), value);
          return build_real (type, cst);
        }

      /* Attempt to evaluate expN(integer) 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;

              real_powi (&x, TYPE_MODE (type), value, n);
              return build_real (type, x);
            }
        }

      /* Optimize expN(logN(x)) = x.  */
      if (flag_unsafe_math_optimizations)
        {
          const enum built_in_function fcode = builtin_mathfn_code (arg);

          if ((value == &dconste
               && (fcode == BUILT_IN_LOG
                   || fcode == BUILT_IN_LOGF
                   || fcode == BUILT_IN_LOGL))
              || (value == &dconst2
                  && (fcode == BUILT_IN_LOG2
                      || fcode == BUILT_IN_LOG2F
                      || fcode == BUILT_IN_LOG2L))
              || (value == &dconst10
                  && (fcode == BUILT_IN_LOG10
                      || fcode == BUILT_IN_LOG10F
                      || fcode == BUILT_IN_LOG10L)))
            return fold_convert (type, TREE_VALUE (TREE_OPERAND (arg, 1)));
        }
    }

  return 0;
}

/* Fold function call to builtin memcpy.  Return
   NULL_TREE if no simplification can be made.  */

static tree
fold_builtin_memcpy (tree exp)
{
  tree arglist = TREE_OPERAND (exp, 1);
  tree dest, src, len;

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

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

  /* If the LEN parameter is zero, return DEST.  */
  if (integer_zerop (len))
    return omit_one_operand (TREE_TYPE (exp), dest, src);

  /* If SRC and DEST are the same (and not volatile), return DEST.  */
  if (operand_equal_p (src, dest, 0))
    return omit_one_operand (TREE_TYPE (exp), dest, len);

  return 0;
}

/* Fold function call to builtin mempcpy.  Return
   NULL_TREE if no simplification can be made.  */

static tree
fold_builtin_mempcpy (tree exp)
{
  tree arglist = TREE_OPERAND (exp, 1);
  tree dest, src, len;

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

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

  /* If the LEN parameter is zero, return DEST.  */
  if (integer_zerop (len))
    return omit_one_operand (TREE_TYPE (exp), dest, src);

  /* If SRC and DEST are the same (and not volatile), return DEST+LEN.  */
  if (operand_equal_p (src, dest, 0))
    {
      tree temp = fold_convert (TREE_TYPE (dest), len);
      temp = fold (build2 (PLUS_EXPR, TREE_TYPE (dest), dest, temp));
      return fold_convert (TREE_TYPE (exp), temp);
    }

  return 0;
}

/* Fold function call to builtin memmove.  Return
   NULL_TREE if no simplification can be made.  */

static tree
fold_builtin_memmove (tree exp)
{
  tree arglist = TREE_OPERAND (exp, 1);
  tree dest, src, len;

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

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

  /* If the LEN parameter is zero, return DEST.  */
  if (integer_zerop (len))
    return omit_one_operand (TREE_TYPE (exp), dest, src);

  /* If SRC and DEST are the same (and not volatile), return DEST.  */
  if (operand_equal_p (src, dest, 0))
    return omit_one_operand (TREE_TYPE (exp), dest, len);

  return 0;
}

/* Fold function call to builtin strcpy.  If LEN is not NULL, it represents
   the length of the string to be copied.  Return NULL_TREE if no
   simplification can be made.  */

tree
fold_builtin_strcpy (tree exp, tree len)
{
  tree arglist = TREE_OPERAND (exp, 1);
  tree dest, src, fn;

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

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

  /* If SRC and DEST are the same (and not volatile), return DEST.  */
  if (operand_equal_p (src, dest, 0))
    return fold_convert (TREE_TYPE (exp), dest);

  if (optimize_size)
    return 0;

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

  if (!len)
    {
      len = c_strlen (src, 1);
      if (! len || TREE_SIDE_EFFECTS (len))
        return 0;
    }

  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, dest, arglist);
  return fold_convert (TREE_TYPE (exp),
                       build_function_call_expr (fn, arglist));
}

/* Fold function call to builtin strncpy.  If SLEN is not NULL, it represents
   the length of the source string.  Return NULL_TREE if no simplification
   can be made.  */

tree
fold_builtin_strncpy (tree exp, tree slen)
{
  tree arglist = TREE_OPERAND (exp, 1);
  tree dest, src, len, fn;

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

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

  /* If the LEN parameter is zero, return DEST.  */
  if (integer_zerop (len))
    return omit_one_operand (TREE_TYPE (exp), dest, src);

  /* We can't compare slen with len as constants below if len is not a
     constant.  */
  if (len == 0 || TREE_CODE (len) != INTEGER_CST)
    return 0;

  if (!slen)
    slen = c_strlen (src, 1);

  /* 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 do not support simplification of this case, though we do
     support it when expanding trees into RTL.  */
  /* FIXME: generate a call to __builtin_memset.  */
  if (tree_int_cst_lt (slen, len))
    return 0;

  /* OK transform into builtin memcpy.  */
  fn = implicit_built_in_decls[BUILT_IN_MEMCPY];
  if (!fn)
    return 0;
  return fold_convert (TREE_TYPE (exp),
                       build_function_call_expr (fn, arglist));
}

/* Fold function call to builtin strchr and strrchr.
   Return NULL_TREE if no simplification can be made.  */

static tree
fold_builtin_strchr (tree exp, bool actually_strrchr)
{
  tree arglist = TREE_OPERAND (exp, 1);
  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 = actually_strrchr ? strrchr (p1, c) : strchr (p1, c);

          if (r == NULL)
            return fold_convert (TREE_TYPE (s1), integer_zero_node);

          /* Return an offset into the constant string argument.  */
          return fold (build2 (PLUS_EXPR, TREE_TYPE (s1),
                               s1, fold_convert (TREE_TYPE (s1),
                                                 ssize_int (r - p1))));
        }

      if (actually_strrchr)
        {
          tree fn;

          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 build_function_call_expr (fn, arglist);
        }

      return 0;
    }
}

/* Fold function call to builtin memcmp.  Return
   NULL_TREE if no simplification can be made.  */

static tree
fold_builtin_memcmp (tree exp)
{
  tree arglist = TREE_OPERAND (exp, 1);
  tree arg1, arg2, len;

  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 (integer_zerop (len))
    {
      tree temp = omit_one_operand (TREE_TYPE (exp), integer_zero_node, arg2);
      return omit_one_operand (TREE_TYPE (exp), temp, arg1);
    }

  /* If ARG1 and ARG2 are the same (and not volatile), return zero.  */
  if (operand_equal_p (arg1, arg2, 0))
    return omit_one_operand (TREE_TYPE (exp), integer_zero_node, len);

  return 0;
}

/* Fold function call to builtin strcmp.  Return
   NULL_TREE if no simplification can be made.  */

static tree
fold_builtin_strcmp (tree exp)
{
  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));

  /* If ARG1 and ARG2 are the same (and not volatile), return zero.  */
  if (operand_equal_p (arg1, arg2, 0))
    return fold_convert (TREE_TYPE (exp), integer_zero_node);

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

  if (p1 && p2)
    {
      tree temp;
      const int i = strcmp (p1, p2);
      if (i < 0)
        temp = integer_minus_one_node;
      else if (i > 0)
        temp = integer_one_node;
      else
        temp = integer_zero_node;
      return fold_convert (TREE_TYPE (exp), temp);
    }

  return 0;
}

/* Fold function call to builtin strncmp.  Return
   NULL_TREE if no simplification can be made.  */

static tree
fold_builtin_strncmp (tree exp)
{
  tree arglist = TREE_OPERAND (exp, 1);
  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 (integer_zerop (len))
    {
      tree temp = omit_one_operand (TREE_TYPE (exp), integer_zero_node, arg2);
      return omit_one_operand (TREE_TYPE (exp), temp, arg1);
    }

  /* If ARG1 and ARG2 are the same (and not volatile), return zero.  */
  if (operand_equal_p (arg1, arg2, 0))
    return omit_one_operand (TREE_TYPE (exp), integer_zero_node, len);

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

  if (host_integerp (len, 1) && p1 && p2)
    {
      tree temp;
      const int i = strncmp (p1, p2, tree_low_cst (len, 1));
      if (i < 0)
        temp = integer_minus_one_node;
      else if (i > 0)
        temp = integer_one_node;
      else
        temp = integer_zero_node;
      return fold_convert (TREE_TYPE (exp), temp);
    }

  return 0;
}

/* Fold function call to builtin signbit, signbitf or signbitl.  Return
   NULL_TREE if no simplification can be made.  */

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

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

  arg = TREE_VALUE (arglist);

  /* If ARG is a compile-time constant, determine the result.  */
  if (TREE_CODE (arg) == REAL_CST
      && !TREE_CONSTANT_OVERFLOW (arg))
    {
      REAL_VALUE_TYPE c;

      c = TREE_REAL_CST (arg);
      temp = REAL_VALUE_NEGATIVE (c) ? integer_one_node : integer_zero_node;
      return fold_convert (TREE_TYPE (exp), temp);
    }

  /* If ARG is non-negative, the result is always zero.  */
  if (tree_expr_nonnegative_p (arg))
    return omit_one_operand (TREE_TYPE (exp), integer_zero_node, arg);

  /* If ARG's format doesn't have signed zeros, return "arg < 0.0".  */
  if (!HONOR_SIGNED_ZEROS (TYPE_MODE (TREE_TYPE (arg))))
    return fold (build2 (LT_EXPR, TREE_TYPE (exp), arg,
                         build_real (TREE_TYPE (arg), dconst0)));

  return NULL_TREE;
}

/* Fold function call to builtin copysign, copysignf or copysignl.
   Return NULL_TREE if no simplification can be made.  */

static tree
fold_builtin_copysign (tree arglist, tree type)
{
  tree arg1, arg2;

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

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

  /* copysign(X,X) is X.  */
  if (operand_equal_p (arg1, arg2, 0))
    return fold_convert (type, arg1);

  /* If ARG1 and ARG2 are compile-time constants, determine the result.  */
  if (TREE_CODE (arg1) == REAL_CST
      && TREE_CODE (arg2) == REAL_CST
      && !TREE_CONSTANT_OVERFLOW (arg1)
      && !TREE_CONSTANT_OVERFLOW (arg2))
    {
      REAL_VALUE_TYPE c1, c2;

      c1 = TREE_REAL_CST (arg1);
      c2 = TREE_REAL_CST (arg2);
      real_copysign (&c1, &c2);
      return build_real (type, c1);
      c1.sign = c2.sign;
    }

  /* copysign(X, Y) is fabs(X) when Y is always non-negative.
     Remember to evaluate Y for side-effects.  */
  if (tree_expr_nonnegative_p (arg2))
    return omit_one_operand (type,
                             fold (build1 (ABS_EXPR, type, arg1)),
                             arg2);

  return NULL_TREE;
}

/* Fold a call to builtin isascii.  */

static tree
fold_builtin_isascii (tree arglist)
{
  if (! validate_arglist (arglist, INTEGER_TYPE, VOID_TYPE))
    return 0;
  else
    {
      /* Transform isascii(c) -> ((c & ~0x7f) == 0).  */
      tree arg = TREE_VALUE (arglist);
      
      arg = fold (build2 (EQ_EXPR, integer_type_node,
                          build2 (BIT_AND_EXPR, integer_type_node, arg,
                                  build_int_2 (~ (unsigned HOST_WIDE_INT) 0x7f,
                                               ~ (HOST_WIDE_INT) 0)),
                          integer_zero_node));
      
      if (in_gimple_form && !TREE_CONSTANT (arg))
        return NULL_TREE;
      else
        return arg;
    }
}

/* Fold a call to builtin toascii.  */

static tree
fold_builtin_toascii (tree arglist)
{
  if (! validate_arglist (arglist, INTEGER_TYPE, VOID_TYPE))
    return 0;
  else
    {
      /* Transform toascii(c) -> (c & 0x7f).  */
      tree arg = TREE_VALUE (arglist);
      
      return fold (build2 (BIT_AND_EXPR, integer_type_node, arg,
                           build_int_2 (0x7f, 0)));
    }
}

/* Fold a call to builtin isdigit.  */

static tree
fold_builtin_isdigit (tree arglist)
{
  if (! validate_arglist (arglist, INTEGER_TYPE, VOID_TYPE))
    return 0;
  else
    {
      /* Transform isdigit(c) -> (unsigned)(c) - '0' <= 9.  */
      /* According to the C standard, isdigit is unaffected by locale.  */
      tree arg = TREE_VALUE (arglist);
      arg = fold_convert (unsigned_type_node, arg);
      arg = build2 (MINUS_EXPR, unsigned_type_node, arg,
                    fold_convert (unsigned_type_node,
                                  build_int_2 (TARGET_DIGIT0, 0)));
      arg = build2 (LE_EXPR, integer_type_node, arg,
                    fold_convert (unsigned_type_node, build_int_2 (9, 0)));
      arg = fold (arg);
      if (in_gimple_form && !TREE_CONSTANT (arg))
        return NULL_TREE;
      else
        return arg;
    }
}

/* Fold a call to fabs, fabsf or fabsl.  */

static tree
fold_builtin_fabs (tree arglist, tree type)
{
  tree arg;

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

  arg = TREE_VALUE (arglist);
  if (TREE_CODE (arg) == REAL_CST)
    return fold_abs_const (arg, type);
  return fold (build1 (ABS_EXPR, type, arg));
}

/* Fold a call to abs, labs, llabs or imaxabs.  */

static tree
fold_builtin_abs (tree arglist, tree type)
{
  tree arg;

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

  arg = TREE_VALUE (arglist);
  if (TREE_CODE (arg) == INTEGER_CST)
    return fold_abs_const (arg, type);
  return fold (build1 (ABS_EXPR, type, arg));
}

/* Fold a call to __builtin_isnan(), __builtin_isinf, __builtin_finite.
   EXP is the CALL_EXPR for the call.  */

static tree
fold_builtin_classify (tree exp, int builtin_index)
{
  tree fndecl = get_callee_fndecl (exp);
  tree arglist = TREE_OPERAND (exp, 1);
  tree type = TREE_TYPE (TREE_TYPE (fndecl));
  tree arg;
  REAL_VALUE_TYPE r;

  if (!validate_arglist (arglist, REAL_TYPE, VOID_TYPE))
    {
      /* Check that we have exactly one argument.  */
      if (arglist == 0)
        {
          error ("too few arguments to function `%s'",
                 IDENTIFIER_POINTER (DECL_NAME (fndecl)));
          return error_mark_node;
        }
      else if (TREE_CHAIN (arglist) != 0)
        {
          error ("too many arguments to function `%s'",
                 IDENTIFIER_POINTER (DECL_NAME (fndecl)));
          return error_mark_node;
        }
      else
        {
          error ("non-floating-point argument to function `%s'",
                 IDENTIFIER_POINTER (DECL_NAME (fndecl)));
          return error_mark_node;
        }
    }

  arg = TREE_VALUE (arglist);
  switch (builtin_index)
    {
    case BUILT_IN_ISINF:
      if (!MODE_HAS_INFINITIES (TYPE_MODE (TREE_TYPE (arg))))
        return omit_one_operand (type, integer_zero_node, arg);

      if (TREE_CODE (arg) == REAL_CST)
        {
          r = TREE_REAL_CST (arg);
          if (real_isinf (&r))
            return real_compare (GT_EXPR, &r, &dconst0)
                   ? integer_one_node : integer_minus_one_node;
          else
            return integer_zero_node;
        }

      return NULL_TREE;

    case BUILT_IN_FINITE:
      if (!MODE_HAS_NANS (TYPE_MODE (TREE_TYPE (arg)))
          && !MODE_HAS_INFINITIES (TYPE_MODE (TREE_TYPE (arg))))
        return omit_one_operand (type, integer_zero_node, arg);

      if (TREE_CODE (arg) == REAL_CST)
        {
          r = TREE_REAL_CST (arg);
          return real_isinf (&r) || real_isnan (&r)
                 ? integer_zero_node : integer_one_node;
        }

      return NULL_TREE;

    case BUILT_IN_ISNAN:
      if (!MODE_HAS_NANS (TYPE_MODE (TREE_TYPE (arg))))
        return omit_one_operand (type, integer_zero_node, arg);

      if (TREE_CODE (arg) == REAL_CST)
        {
          r = TREE_REAL_CST (arg);
          return real_isnan (&r) ? integer_one_node : integer_zero_node;
        }

      arg = builtin_save_expr (arg);
      return fold (build2 (UNORDERED_EXPR, type, arg, arg));

    default:
      abort ();
    }
}

/* Fold a call to an unordered comparison function such as
   __builtin_isgreater().  EXP is the CALL_EXPR for the call.
   UNORDERED_CODE and ORDERED_CODE are comparison codes that give
   the opposite of the desired result.  UNORDERED_CODE is used
   for modes that can hold NaNs and ORDERED_CODE is used for
   the rest.  */

static tree
fold_builtin_unordered_cmp (tree exp,
                            enum tree_code unordered_code,
                            enum tree_code ordered_code)
{
  tree fndecl = get_callee_fndecl (exp);
  tree arglist = TREE_OPERAND (exp, 1);
  tree type = TREE_TYPE (TREE_TYPE (fndecl));
  enum tree_code code;
  tree arg0, arg1;

  if (!validate_arglist (arglist, REAL_TYPE, REAL_TYPE, VOID_TYPE))
    {
      enum tree_code code0, code1;
      tree type0, type1;
      tree cmp_type = 0;

      /* Check that we have exactly two arguments.  */
      if (arglist == 0 || TREE_CHAIN (arglist) == 0)
        {
          error ("too few arguments to function `%s'",
                 IDENTIFIER_POINTER (DECL_NAME (fndecl)));
          return error_mark_node;
        }
      else if (TREE_CHAIN (TREE_CHAIN (arglist)) != 0)
        {
          error ("too many arguments to function `%s'",
                 IDENTIFIER_POINTER (DECL_NAME (fndecl)));
          return error_mark_node;
        }

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

      type0 = TREE_TYPE (arg0);
      type1 = TREE_TYPE (arg1);

      code0 = TREE_CODE (type0);
      code1 = TREE_CODE (type1);

      if (code0 == REAL_TYPE && code1 == REAL_TYPE)
        /* Choose the wider of two real types.  */
        cmp_type = TYPE_PRECISION (type0) >= TYPE_PRECISION (type1)
                   ? type0 : type1;
      else if (code0 == REAL_TYPE && code1 == INTEGER_TYPE)
        cmp_type = type0;
      else if (code0 == INTEGER_TYPE && code1 == REAL_TYPE)
        cmp_type = type1;
      else
        {
          error ("non-floating-point argument to function `%s'",
                 IDENTIFIER_POINTER (DECL_NAME (fndecl)));
          return error_mark_node;
        }

      arg0 = fold_convert (cmp_type, arg0);
      arg1 = fold_convert (cmp_type, arg1);
    }
  else
    {
      arg0 = TREE_VALUE (arglist);
      arg1 = TREE_VALUE (TREE_CHAIN (arglist));
    }

  if (unordered_code == UNORDERED_EXPR)
    {
      if (!MODE_HAS_NANS (TYPE_MODE (TREE_TYPE (arg0))))
        return omit_two_operands (type, integer_zero_node, arg0, arg1);
      return fold (build2 (UNORDERED_EXPR, type, arg0, arg1));
    }

  code = MODE_HAS_NANS (TYPE_MODE (TREE_TYPE (arg0))) ? unordered_code
                                                      : ordered_code;
  return fold (build1 (TRUTH_NOT_EXPR, type,
                       fold (build2 (code, type, arg0, arg1))));
}

/* Used by constant folding to simplify calls to builtin functions.  EXP is
   the CALL_EXPR of a call to a builtin function.  IGNORE is true if the
   result of the function call is ignored.  This function returns NULL_TREE
   if no simplification was possible.  */

static tree
fold_builtin_1 (tree exp, bool ignore)
{
  tree fndecl = get_callee_fndecl (exp);
  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_EXPECT:
      return fold_builtin_expect (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 = fold_convert (size_type_node, len);
              return len;
            }
        }
      break;

    case BUILT_IN_FABS:
    case BUILT_IN_FABSF:
    case BUILT_IN_FABSL:
      return fold_builtin_fabs (arglist, type);

    case BUILT_IN_ABS:
    case BUILT_IN_LABS:
    case BUILT_IN_LLABS:
    case BUILT_IN_IMAXABS:
      return fold_builtin_abs (arglist, type);

    case BUILT_IN_CONJ:
    case BUILT_IN_CONJF:
    case BUILT_IN_CONJL:
      if (validate_arglist (arglist, COMPLEX_TYPE, VOID_TYPE))
        return fold (build1 (CONJ_EXPR, type, TREE_VALUE (arglist)));
      break;

    case BUILT_IN_CREAL:
    case BUILT_IN_CREALF:
    case BUILT_IN_CREALL:
      if (validate_arglist (arglist, COMPLEX_TYPE, VOID_TYPE))
        return non_lvalue (fold (build1 (REALPART_EXPR, type,
                                         TREE_VALUE (arglist))));
      break;

    case BUILT_IN_CIMAG:
    case BUILT_IN_CIMAGF:
    case BUILT_IN_CIMAGL:
      if (validate_arglist (arglist, COMPLEX_TYPE, VOID_TYPE))
        return non_lvalue (fold (build1 (IMAGPART_EXPR, type,
                                         TREE_VALUE (arglist))));
      break;

    case BUILT_IN_CABS:
    case BUILT_IN_CABSF:
    case BUILT_IN_CABSL:
      return fold_builtin_cabs (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(expN(x)) = expN(x*0.5).  */
          fcode = builtin_mathfn_code (arg);
          if (flag_unsafe_math_optimizations && BUILTIN_EXPONENT_P (fcode))
            {
              tree expfn = TREE_OPERAND (TREE_OPERAND (arg, 0), 0);
              arg = fold (build2 (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(Nroot(x)) -> pow(x,1/(2*N)).  */
          if (flag_unsafe_math_optimizations && BUILTIN_ROOT_P (fcode))
            {
              tree powfn = mathfn_built_in (type, BUILT_IN_POW);
              
              if (powfn)
                {
                  tree arg0 = TREE_VALUE (TREE_OPERAND (arg, 1));
                  tree tree_root;
                  /* The inner root was either sqrt or cbrt.  */
                  REAL_VALUE_TYPE dconstroot =
                    BUILTIN_SQRT_P (fcode) ? dconsthalf : dconstthird;
                  
                  /* Adjust for the outer root.  */
                  SET_REAL_EXP (&dconstroot, REAL_EXP (&dconstroot) - 1);
                  dconstroot = real_value_truncate (TYPE_MODE (type), dconstroot);
                  tree_root = build_real (type, dconstroot);
                  arglist = tree_cons (NULL_TREE, arg0,
                                       build_tree_list (NULL_TREE, tree_root));
                  return build_function_call_expr (powfn, 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 (build2 (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_CBRT:
    case BUILT_IN_CBRTF:
    case BUILT_IN_CBRTL:
      if (validate_arglist (arglist, REAL_TYPE, VOID_TYPE))
        {
          tree arg = TREE_VALUE (arglist);
          const enum built_in_function fcode = builtin_mathfn_code (arg);

          /* Optimize cbrt of constant value.  */
          if (real_zerop (arg) || real_onep (arg) || real_minus_onep (arg))
            return arg;

          /* Optimize cbrt(expN(x)) -> expN(x/3).  */
          if (flag_unsafe_math_optimizations && BUILTIN_EXPONENT_P (fcode))
            {
              tree expfn = TREE_OPERAND (TREE_OPERAND (arg, 0), 0);
              const REAL_VALUE_TYPE third_trunc =
                real_value_truncate (TYPE_MODE (type), dconstthird);
              arg = fold (build2 (MULT_EXPR, type,
                                  TREE_VALUE (TREE_OPERAND (arg, 1)),
                                  build_real (type, third_trunc)));
              arglist = build_tree_list (NULL_TREE, arg);
              return build_function_call_expr (expfn, arglist);
            }

          /* Optimize cbrt(sqrt(x)) -> pow(x,1/6).  */
          /* We don't optimize cbrt(cbrt(x)) -> pow(x,1/9) because if
             x is negative pow will error but cbrt won't.  */
          if (flag_unsafe_math_optimizations && BUILTIN_SQRT_P (fcode))
            {
              tree powfn = mathfn_built_in (type, BUILT_IN_POW);

              if (powfn)
                {
                  tree arg0 = TREE_VALUE (TREE_OPERAND (arg, 1));
                  tree tree_root;
                  REAL_VALUE_TYPE dconstroot = dconstthird;

                  SET_REAL_EXP (&dconstroot, REAL_EXP (&dconstroot) - 1);
                  dconstroot = real_value_truncate (TYPE_MODE (type), dconstroot);
                  tree_root = build_real (type, dconstroot);
                  arglist = tree_cons (NULL_TREE, arg0,
                                       build_tree_list (NULL_TREE, tree_root));
                  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:
      return fold_builtin_exponent (exp, &dconste);

    case BUILT_IN_EXP2:
    case BUILT_IN_EXP2F:
    case BUILT_IN_EXP2L:
      return fold_builtin_exponent (exp, &dconst2);

    case BUILT_IN_EXP10:
    case BUILT_IN_EXP10F:
    case BUILT_IN_EXP10L:
    case BUILT_IN_POW10:
    case BUILT_IN_POW10F:
    case BUILT_IN_POW10L:
      return fold_builtin_exponent (exp, &dconst10);

    case BUILT_IN_LOG:
    case BUILT_IN_LOGF:
    case BUILT_IN_LOGL:
      return fold_builtin_logarithm (exp, &dconste);

    case BUILT_IN_LOG2:
    case BUILT_IN_LOG2F:
    case BUILT_IN_LOG2L:
      return fold_builtin_logarithm (exp, &dconst2);

    case BUILT_IN_LOG10:
    case BUILT_IN_LOG10F:
    case BUILT_IN_LOG10L:
      return fold_builtin_logarithm (exp, &dconst10);

    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;

              real_convert (&cst, TYPE_MODE (type), &dconstpi);
              SET_REAL_EXP (&cst, REAL_EXP (&cst) - 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 (build2 (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 = mathfn_built_in (type, BUILT_IN_SQRT);

                  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(expN(x),y) = expN(x*y).  */
          fcode = builtin_mathfn_code (arg0);
          if (flag_unsafe_math_optimizations && BUILTIN_EXPONENT_P (fcode))
            {
              tree expfn = TREE_OPERAND (TREE_OPERAND (arg0, 0), 0);
              tree arg = TREE_VALUE (TREE_OPERAND (arg0, 1));
              arg = fold (build2 (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 && BUILTIN_SQRT_P (fcode))
            {
              tree narg0 = TREE_VALUE (TREE_OPERAND (arg0, 1));
              tree narg1 = fold (build2 (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 (build2 (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:
      return fold_builtin_round (exp);

    case BUILT_IN_NEARBYINT:
    case BUILT_IN_NEARBYINTF:
    case BUILT_IN_NEARBYINTL:
    case BUILT_IN_RINT:
    case BUILT_IN_RINTF:
    case BUILT_IN_RINTL:
      return fold_trunc_transparent_mathfn (exp);

    case BUILT_IN_LROUND:
    case BUILT_IN_LROUNDF:
    case BUILT_IN_LROUNDL:
    case BUILT_IN_LLROUND:
    case BUILT_IN_LLROUNDF:
    case BUILT_IN_LLROUNDL:
      return fold_builtin_lround (exp);

    case BUILT_IN_LRINT:
    case BUILT_IN_LRINTF:
    case BUILT_IN_LRINTL:
    case BUILT_IN_LLRINT:
    case BUILT_IN_LLRINTF:
    case BUILT_IN_LLRINTL:
      return fold_fixed_mathfn (exp);

    case BUILT_IN_FFS:
    case BUILT_IN_FFSL:
    case BUILT_IN_FFSLL:
    case BUILT_IN_CLZ:
    case BUILT_IN_CLZL:
    case BUILT_IN_CLZLL:
    case BUILT_IN_CTZ:
    case BUILT_IN_CTZL:
    case BUILT_IN_CTZLL:
    case BUILT_IN_POPCOUNT:
    case BUILT_IN_POPCOUNTL:
    case BUILT_IN_POPCOUNTLL:
    case BUILT_IN_PARITY:
    case BUILT_IN_PARITYL:
    case BUILT_IN_PARITYLL:
      return fold_builtin_bitop (exp);

    case BUILT_IN_MEMCPY:
      return fold_builtin_memcpy (exp);

    case BUILT_IN_MEMPCPY:
      return fold_builtin_mempcpy (exp);

    case BUILT_IN_MEMMOVE:
      return fold_builtin_memmove (exp);

    case BUILT_IN_STRCPY:
      return fold_builtin_strcpy (exp, NULL_TREE);

    case BUILT_IN_STRNCPY:
      return fold_builtin_strncpy (exp, NULL_TREE);

    case BUILT_IN_INDEX:
    case BUILT_IN_STRCHR:
      return fold_builtin_strchr (exp, false);

    case BUILT_IN_RINDEX:
    case BUILT_IN_STRRCHR:
      return fold_builtin_strchr (exp, true);

    case BUILT_IN_MEMCMP:
      return fold_builtin_memcmp (exp);

    case BUILT_IN_STRCMP:
      return fold_builtin_strcmp (exp);

    case BUILT_IN_STRNCMP:
      return fold_builtin_strncmp (exp);

    case BUILT_IN_SIGNBIT:
    case BUILT_IN_SIGNBITF:
    case BUILT_IN_SIGNBITL:
      return fold_builtin_signbit (exp);

    case BUILT_IN_ISASCII:
      return fold_builtin_isascii (arglist);

    case BUILT_IN_TOASCII:
      return fold_builtin_toascii (arglist);

    case BUILT_IN_ISDIGIT:
      return fold_builtin_isdigit (arglist);

    case BUILT_IN_COPYSIGN:
    case BUILT_IN_COPYSIGNF:
    case BUILT_IN_COPYSIGNL:
      return fold_builtin_copysign (arglist, type);

    case BUILT_IN_FINITE:
    case BUILT_IN_FINITEF:
    case BUILT_IN_FINITEL:
      return fold_builtin_classify (exp, BUILT_IN_FINITE);

    case BUILT_IN_ISINF:
    case BUILT_IN_ISINFF:
    case BUILT_IN_ISINFL:
      return fold_builtin_classify (exp, BUILT_IN_ISINF);

    case BUILT_IN_ISNAN:
    case BUILT_IN_ISNANF:
    case BUILT_IN_ISNANL:
      return fold_builtin_classify (exp, BUILT_IN_ISNAN);

    case BUILT_IN_ISGREATER:
      return fold_builtin_unordered_cmp (exp, UNLE_EXPR, LE_EXPR);
    case BUILT_IN_ISGREATEREQUAL:
      return fold_builtin_unordered_cmp (exp, UNLT_EXPR, LT_EXPR);
    case BUILT_IN_ISLESS:
      return fold_builtin_unordered_cmp (exp, UNGE_EXPR, GE_EXPR);
    case BUILT_IN_ISLESSEQUAL:
      return fold_builtin_unordered_cmp (exp, UNGT_EXPR, GT_EXPR);
    case BUILT_IN_ISLESSGREATER:
      return fold_builtin_unordered_cmp (exp, UNEQ_EXPR, EQ_EXPR);
    case BUILT_IN_ISUNORDERED:
      return fold_builtin_unordered_cmp (exp, UNORDERED_EXPR, NOP_EXPR);

    case BUILT_IN_FPUTS:
      return fold_builtin_fputs (arglist, ignore, false, NULL_TREE);

    case BUILT_IN_FPUTS_UNLOCKED:
      return fold_builtin_fputs (arglist, ignore, true, NULL_TREE);

    default:
      break;
    }

  return 0;
}

/* A wrapper function for builtin folding that prevents warnings for
   "statement without effect" and the like, caused by removing the 
   call node earlier than the warning is generated.  */

tree
fold_builtin (tree exp, bool ignore)
{
  exp = fold_builtin_1 (exp, ignore);
  if (exp)
    {
      /* ??? Don't clobber shared nodes such as integer_zero_node.  */
      if (TREE_CODE_CLASS (TREE_CODE (exp)) == 'c')
        exp = build1 (NOP_EXPR, TREE_TYPE (exp), exp);
      TREE_NO_WARNING (exp) = 1;
    }
  return exp;
}

/* 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 = build3 (CALL_EXPR, TREE_TYPE (TREE_TYPE (fn)),
                      call_expr, arglist, NULL_TREE);
  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 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;
}

/* 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 false;

  exp = get_base_address (TREE_OPERAND (exp, 0));
  if (!exp)
    return false;

  /* Make sure we call decl_readonly_section only for trees it
     can handle (since it returns true for everything it doesn't
     understand).  */
  if (TREE_CODE (exp) == STRING_CST 
      || TREE_CODE (exp) == CONSTRUCTOR
      || (TREE_CODE (exp) == VAR_DECL && TREE_STATIC (exp)))
    return decl_readonly_section (exp, 0);
  else
    return false;
}

/* Front-end to the simplify_builtin_XXX routines.

   EXP is a call to a builtin function.  If possible try to simplify
   that into a constant, expression or call to a more efficient
   builtin function.

   If IGNORE is nonzero, then the result of this builtin function
   call is ignored.

   If simplification is possible, return the simplified tree, otherwise
   return NULL_TREE.  */

tree
simplify_builtin (tree exp, 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);
  tree val;

  switch (fcode)
    {
    case BUILT_IN_FPUTS:
      val = fold_builtin_fputs (arglist, ignore, false, NULL_TREE);
      break;
    case BUILT_IN_FPUTS_UNLOCKED:
      val = fold_builtin_fputs (arglist, ignore, true, NULL_TREE);
      break;
    case BUILT_IN_STRSTR:
      val = simplify_builtin_strstr (arglist);
      break;
    case BUILT_IN_STRCAT:
      val = simplify_builtin_strcat (arglist);
      break;
    case BUILT_IN_STRNCAT:
      val = simplify_builtin_strncat (arglist);
      break;
    case BUILT_IN_STRSPN:
      val = simplify_builtin_strspn (arglist);
      break;
    case BUILT_IN_STRCSPN:
      val = simplify_builtin_strcspn (arglist);
      break;
    case BUILT_IN_STRCHR:
    case BUILT_IN_INDEX:
      val = simplify_builtin_strchr (arglist);
      break;
    case BUILT_IN_STRRCHR:
    case BUILT_IN_RINDEX:
      val = simplify_builtin_strrchr (arglist);
      break;
    case BUILT_IN_STRCPY:
      val = fold_builtin_strcpy (exp, NULL_TREE);
      break;
    case BUILT_IN_STRNCPY:
      val = fold_builtin_strncpy (exp, NULL_TREE);
      break;
    case BUILT_IN_STRCMP:
      val = simplify_builtin_strcmp (arglist);
      break;
    case BUILT_IN_STRNCMP:
      val = simplify_builtin_strncmp (arglist);
      break;
    case BUILT_IN_STRPBRK:
      val = simplify_builtin_strpbrk (arglist);
      break;
    case BUILT_IN_BCMP:
    case BUILT_IN_MEMCMP:
      val = simplify_builtin_memcmp (arglist);
      break;
    case BUILT_IN_VA_START:
      simplify_builtin_va_start (arglist);
      val = NULL_TREE;
      break;
    case BUILT_IN_SPRINTF:
      val = simplify_builtin_sprintf (arglist, ignore);
      break;
    case BUILT_IN_CONSTANT_P:
      val = fold_builtin_constant_p (arglist);
      /* Gimplification will pull the CALL_EXPR for the builtin out of
         an if condition.  When not optimizing, we'll not CSE it back.
         To avoid link error types of regressions, return false now.  */
      if (!val && !optimize)
        val = integer_zero_node;
      break;
    default:
      val = NULL_TREE;
      break;
    }

  if (val)
    val = fold_convert (TREE_TYPE (exp), val);
  return val;
}

/* Simplify a call to the strstr builtin.

   Return 0 if no simplification was possible, otherwise return the
   simplified form of the call as a tree.

   The simplified form may be a constant or other expression which
   computes the same value, but in a more efficient manner (including
   calls to other builtin functions).

   The call may contain arguments which need to be evaluated, but
   which are not useful to determine the result of the call.  In
   this case we return a chain of COMPOUND_EXPRs.  The LHS of each
   COMPOUND_EXPR will be an argument which must be evaluated.
   COMPOUND_EXPRs are chained through their RHS.  The RHS of the last
   COMPOUND_EXPR in the chain will contain the tree for the simplified
   form of the builtin function call.  */

static tree
simplify_builtin_strstr (tree arglist)
{
  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 fold_convert (TREE_TYPE (s1), integer_zero_node);

          /* Return an offset into the constant string argument.  */
          return fold (build2 (PLUS_EXPR, TREE_TYPE (s1),
                               s1, fold_convert (TREE_TYPE (s1),
                                                 ssize_int (r - p1))));
        }

      if (p2[0] == '\0')
        return s1;

      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 build_function_call_expr (fn, arglist);
    }
}

/* Simplify a call to the strstr builtin.

   Return 0 if no simplification was possible, otherwise return the
   simplified form of the call as a tree.

   The simplified form may be a constant or other expression which
   computes the same value, but in a more efficient manner (including
   calls to other builtin functions).

   The call may contain arguments which need to be evaluated, but
   which are not useful to determine the result of the call.  In
   this case we return a chain of COMPOUND_EXPRs.  The LHS of each
   COMPOUND_EXPR will be an argument which must be evaluated.
   COMPOUND_EXPRs are chained through their RHS.  The RHS of the last
   COMPOUND_EXPR in the chain will contain the tree for the simplified
   form of the builtin function call.  */

static tree
simplify_builtin_strchr (tree arglist)
{
  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 fold_convert (TREE_TYPE (s1), integer_zero_node);

          /* Return an offset into the constant string argument.  */
          return fold (build2 (PLUS_EXPR, TREE_TYPE (s1),
                               s1, fold_convert (TREE_TYPE (s1),
                                                 ssize_int (r - p1))));
        }

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

/* Simplify a call to the strrchr builtin.

   Return 0 if no simplification was possible, otherwise return the
   simplified form of the call as a tree.

   The simplified form may be a constant or other expression which
   computes the same value, but in a more efficient manner (including
   calls to other builtin functions).

   The call may contain arguments which need to be evaluated, but
   which are not useful to determine the result of the call.  In
   this case we return a chain of COMPOUND_EXPRs.  The LHS of each
   COMPOUND_EXPR will be an argument which must be evaluated.
   COMPOUND_EXPRs are chained through their RHS.  The RHS of the last
   COMPOUND_EXPR in the chain will contain the tree for the simplified
   form of the builtin function call.  */

static tree
simplify_builtin_strrchr (tree arglist)
{
  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 fold_convert (TREE_TYPE (s1), integer_zero_node);

          /* Return an offset into the constant string argument.  */
          return fold (build2 (PLUS_EXPR, TREE_TYPE (s1),
                               s1, fold_convert (TREE_TYPE (s1),
                                                 ssize_int (r - p1))));
        }

      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 build_function_call_expr (fn, arglist);
    }
}

/* Simplify a call to the strpbrk builtin.

   Return 0 if no simplification was possible, otherwise return the
   simplified form of the call as a tree.

   The simplified form may be a constant or other expression which
   computes the same value, but in a more efficient manner (including
   calls to other builtin functions).

   The call may contain arguments which need to be evaluated, but
   which are not useful to determine the result of the call.  In
   this case we return a chain of COMPOUND_EXPRs.  The LHS of each
   COMPOUND_EXPR will be an argument which must be evaluated.
   COMPOUND_EXPRs are chained through their RHS.  The RHS of the last
   COMPOUND_EXPR in the chain will contain the tree for the simplified
   form of the builtin function call.  */

static tree
simplify_builtin_strpbrk (tree arglist)
{
  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 fold_convert (TREE_TYPE (s1), integer_zero_node);

          /* Return an offset into the constant string argument.  */
          return fold (build2 (PLUS_EXPR, TREE_TYPE (s1),
                               s1, fold_convert (TREE_TYPE (s1),
                                                 ssize_int (r - p1))));
        }

      if (p2[0] == '\0')
        /* strpbrk(x, "") == NULL.
           Evaluate and ignore s1 in case it had side-effects.  */
        return omit_one_operand (TREE_TYPE (s1), integer_zero_node, s1);

      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 build_function_call_expr (fn, arglist);
    }
}

/* Simplify a call to the memcmp builtin.

   Return 0 if no simplification was possible, otherwise return the
   simplified form of the call as a tree.

   The simplified form may be a constant or other expression which
   computes the same value, but in a more efficient manner (including
   calls to other builtin functions).

   The call may contain arguments which need to be evaluated, but
   which are not useful to determine the result of the call.  In
   this case we return a chain of COMPOUND_EXPRs.  The LHS of each
   COMPOUND_EXPR will be an argument which must be evaluated.
   COMPOUND_EXPRs are chained through their RHS.  The RHS of the last
   COMPOUND_EXPR in the chain will contain the tree for the simplified
   form of the builtin function call.  */

static tree
simplify_builtin_memcmp (tree arglist)
{
  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.  */
    return omit_two_operands (integer_type_node, integer_zero_node,
                              arg1, arg2);

  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
              ? integer_minus_one_node
              : (r > 0 ? integer_one_node : integer_zero_node));
    }

  /* 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))));
      return fold (build2 (MINUS_EXPR, integer_type_node, ind1, ind2));
    }

  return 0;
}

/* Simplify a call to the strcmp builtin.

   Return 0 if no simplification was possible, otherwise return the
   simplified form of the call as a tree.

   The simplified form may be a constant or other expression which
   computes the same value, but in a more efficient manner (including
   calls to other builtin functions).

   The call may contain arguments which need to be evaluated, but
   which are not useful to determine the result of the call.  In
   this case we return a chain of COMPOUND_EXPRs.  The LHS of each
   COMPOUND_EXPR will be an argument which must be evaluated.
   COMPOUND_EXPRs are chained through their RHS.  The RHS of the last
   COMPOUND_EXPR in the chain will contain the tree for the simplified
   form of the builtin function call.  */

static tree
simplify_builtin_strcmp (tree arglist)
{
  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));

  /* If both arguments are equal (and not volatile), return zero.  */
  if (operand_equal_p (arg1, arg2, 0))
    return integer_zero_node;

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

  if (p1 && p2)
    {
      const int i = strcmp (p1, p2);
      return (i < 0
              ? integer_minus_one_node
              : (i > 0 ? integer_one_node : integer_zero_node));
    }

  /* 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))));
      return fold (build2 (MINUS_EXPR, integer_type_node, ind1, ind2));
    }

  return 0;
}

/* Simplify a call to the strncmp builtin.

   Return 0 if no simplification was possible, otherwise return the
   simplified form of the call as a tree.

   The simplified form may be a constant or other expression which
   computes the same value, but in a more efficient manner (including
   calls to other builtin functions).

   The call may contain arguments which need to be evaluated, but
   which are not useful to determine the result of the call.  In
   this case we return a chain of COMPOUND_EXPRs.  The LHS of each
   COMPOUND_EXPR will be an argument which must be evaluated.
   COMPOUND_EXPRs are chained through their RHS.  The RHS of the last
   COMPOUND_EXPR in the chain will contain the tree for the simplified
   form of the builtin function call.  */

static tree
simplify_builtin_strncmp (tree arglist)
{
  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 (integer_zerop (arg3))
    /* Evaluate and ignore arg1 and arg2 in case they have side-effects.  */
    return omit_two_operands (integer_type_node, integer_zero_node,
                              arg1, arg2);

  /* If arg1 and arg2 are equal (and not volatile), return zero.  */
  if (operand_equal_p (arg1, arg2, 0))
    /* Evaluate and ignore arg3 in case it has side-effects.  */
    return omit_one_operand (integer_type_node, integer_zero_node, arg3);

  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
              ? integer_minus_one_node
              : (r > 0 ? integer_one_node : integer_zero_node));
    }

  /* 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))));
      return fold (build2 (MINUS_EXPR, integer_type_node, ind1, ind2));
    }

  return 0;
}

/* Simplify a call to the strcat builtin.

   Return 0 if no simplification was possible, otherwise return the
   simplified form of the call as a tree.

   The simplified form may be a constant or other expression which
   computes the same value, but in a more efficient manner (including
   calls to other builtin functions).

   The call may contain arguments which need to be evaluated, but
   which are not useful to determine the result of the call.  In
   this case we return a chain of COMPOUND_EXPRs.  The LHS of each
   COMPOUND_EXPR will be an argument which must be evaluated.
   COMPOUND_EXPRs are chained through their RHS.  The RHS of the last
   COMPOUND_EXPR in the chain will contain the tree for the simplified
   form of the builtin function call.  */

static tree
simplify_builtin_strcat (tree arglist)
{
  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 the string length is zero, return the dst parameter.  */
      if (p && *p == '\0')
        return dst;

      return 0;
    }
}

/* Simplify a call to the strncat builtin.

   Return 0 if no simplification was possible, otherwise return the
   simplified form of the call as a tree.

   The simplified form may be a constant or other expression which
   computes the same value, but in a more efficient manner (including
   calls to other builtin functions).

   The call may contain arguments which need to be evaluated, but
   which are not useful to determine the result of the call.  In
   this case we return a chain of COMPOUND_EXPRs.  The LHS of each
   COMPOUND_EXPR will be an argument which must be evaluated.
   COMPOUND_EXPRs are chained through their RHS.  The RHS of the last
   COMPOUND_EXPR in the chain will contain the tree for the simplified
   form of the builtin function call.  */

static tree
simplify_builtin_strncat (tree arglist)
{
  if (!validate_arglist (arglist,
                         POINTER_TYPE, POINTER_TYPE, INTEGER_TYPE, VOID_TYPE))
    return 0;
  else
    {
      tree dst = TREE_VALUE (arglist);
      tree src = TREE_VALUE (TREE_CHAIN (arglist));
      tree 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'))
        return omit_two_operands (TREE_TYPE (dst), dst, src, len);

      /* 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 build_function_call_expr (fn, newarglist);
        }
      return 0;
    }
}

/* Simplify a call to the strspn builtin.

   Return 0 if no simplification was possible, otherwise return the
   simplified form of the call as a tree.

   The simplified form may be a constant or other expression which
   computes the same value, but in a more efficient manner (including
   calls to other builtin functions).

   The call may contain arguments which need to be evaluated, but
   which are not useful to determine the result of the call.  In
   this case we return a chain of COMPOUND_EXPRs.  The LHS of each
   COMPOUND_EXPR will be an argument which must be evaluated.
   COMPOUND_EXPRs are chained through their RHS.  The RHS of the last
   COMPOUND_EXPR in the chain will contain the tree for the simplified
   form of the builtin function call.  */

static tree
simplify_builtin_strspn (tree arglist)
{
  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 size_int (r);
        }

      /* 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.  */
        return omit_two_operands (integer_type_node, integer_zero_node,
                                  s1, s2);
      return 0;
    }
}

/* Simplify a call to the strcspn builtin.

   Return 0 if no simplification was possible, otherwise return the
   simplified form of the call as a tree.

   The simplified form may be a constant or other expression which
   computes the same value, but in a more efficient manner (including
   calls to other builtin functions).

   The call may contain arguments which need to be evaluated, but
   which are not useful to determine the result of the call.  In
   this case we return a chain of COMPOUND_EXPRs.  The LHS of each
   COMPOUND_EXPR will be an argument which must be evaluated.
   COMPOUND_EXPRs are chained through their RHS.  The RHS of the last
   COMPOUND_EXPR in the chain will contain the tree for the simplified
   form of the builtin function call.  */

static tree
simplify_builtin_strcspn (tree arglist)
{
  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 size_int (r);
        }

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

      /* 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 build_function_call_expr (fn, newarglist);
        }
      return 0;
    }
}

/* Fold a call to the fputs builtin.  IGNORE is true if the value returned
   by the builtin will be ignored.  UNLOCKED is true is true if this
   actually a call to fputs_unlocked.  If LEN in non-NULL, it represents
   the known length of the string.  Return NULL_TREE if no simplification
   was possible.  */

tree
fold_builtin_fputs (tree arglist, bool ignore, bool unlocked, tree len)
{
  tree 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 (!ignore || !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;

  if (! len)
    len = c_strlen (TREE_VALUE (arglist), 0);

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

  switch (compare_tree_int (len, 1))
    {
    case -1: /* length is 0, delete the call entirely .  */
      return omit_one_operand (integer_type_node, integer_zero_node,
                               TREE_VALUE (TREE_CHAIN (arglist)));

    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 fold_convert (integer_type_node,
                       build_function_call_expr (fn, arglist));
}

static void
simplify_builtin_va_start (tree arglist)
{
  tree chain = TREE_CHAIN (arglist);

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

  simplify_builtin_next_arg (chain);
}

static void
simplify_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");
  else 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");
      TREE_VALUE (arglist) = arg;
    }
  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");
}


/* Simplify a call to the sprintf builtin.

   Return 0 if no simplification was possible, otherwise return the
   simplified form of the call as a tree.  If IGNORED is true, it means that
   the caller does not use the returned value of the function.  */

static tree
simplify_builtin_sprintf (tree arglist, int ignored)
{
  tree call, retval, dest, fmt;
  const char *fmt_str = NULL;

  /* Verify the required arguments in the original call.  We deal with two
     types of sprintf() calls: 'sprintf (str, fmt)' and
     'sprintf (dest, "%s", orig)'.  */
  if (!validate_arglist (arglist, POINTER_TYPE, POINTER_TYPE, VOID_TYPE)
      && !validate_arglist (arglist, POINTER_TYPE, POINTER_TYPE, POINTER_TYPE,
                            VOID_TYPE))
    return NULL_TREE;

  /* Get the destination string and the format specifier.  */
  dest = TREE_VALUE (arglist);
  fmt = TREE_VALUE (TREE_CHAIN (arglist));

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

  call = NULL_TREE;
  retval = NULL_TREE;

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

      if (!fn)
        return NULL_TREE;

      /* Convert sprintf (str, fmt) into strcpy (str, fmt) when
         'format' is known to contain no % formats.  */
      arglist = build_tree_list (NULL_TREE, fmt);
      arglist = tree_cons (NULL_TREE, dest, arglist);
      call = build_function_call_expr (fn, arglist);
      if (!ignored)
        retval = build_int_2 (strlen (fmt_str), 0);
    }

  /* If the format is "%s", use strcpy if the result isn't used.  */
  else if (fmt_str && strcmp (fmt_str, "%s") == 0)
    {
      tree fn, orig;
      fn = implicit_built_in_decls[BUILT_IN_STRCPY];

      if (!fn)
        return NULL_TREE;

      /* Convert sprintf (str1, "%s", str2) into strcpy (str1, str2).  */
      orig = TREE_VALUE (TREE_CHAIN (TREE_CHAIN (arglist)));
      arglist = build_tree_list (NULL_TREE, orig);
      arglist = tree_cons (NULL_TREE, dest, arglist);
      if (!ignored)
        {
          retval = c_strlen (orig, 1);
          if (!retval || TREE_CODE (retval) != INTEGER_CST)
            return NULL_TREE;
        }
      call = build_function_call_expr (fn, arglist);
    }

  if (call && retval)
    {
      retval = convert
        (TREE_TYPE (TREE_TYPE (implicit_built_in_decls[BUILT_IN_SPRINTF])),
         retval);
      return build2 (COMPOUND_EXPR, TREE_TYPE (retval), call, retval);
    }
  else
    return call;
}