2014-10-31 Richard Biener <rguenther@suse.de>

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

/* Convert tree expression to rtl instructions, for GNU compiler.
   Copyright (C) 1988-2014 Free Software Foundation, Inc.

This file is part of GCC.

GCC is free software; you can redistribute it and/or modify it under
the terms of the GNU General Public License as published by the Free
Software Foundation; either version 3, or (at your option) any later
version.

GCC is distributed in the hope that it will be useful, but WITHOUT ANY
WARRANTY; without even the implied warranty of MERCHANTABILITY or
FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License
for more details.

You should have received a copy of the GNU General Public License
along with GCC; see the file COPYING3.  If not see
<http://www.gnu.org/licenses/>.  */

#include "config.h"
#include "system.h"
#include "coretypes.h"
#include "tm.h"
#include "machmode.h"
#include "rtl.h"
#include "tree.h"
#include "stringpool.h"
#include "stor-layout.h"
#include "attribs.h"
#include "varasm.h"
#include "flags.h"
#include "regs.h"
#include "hard-reg-set.h"
#include "except.h"
#include "hashtab.h"
#include "hash-set.h"
#include "vec.h"
#include "input.h"
#include "function.h"
#include "insn-config.h"
#include "insn-attr.h"
/* Include expr.h after insn-config.h so we get HAVE_conditional_move.  */
#include "expr.h"
#include "optabs.h"
#include "libfuncs.h"
#include "recog.h"
#include "reload.h"
#include "typeclass.h"
#include "toplev.h"
#include "langhooks.h"
#include "intl.h"
#include "tm_p.h"
#include "tree-iterator.h"
#include "predict.h"
#include "dominance.h"
#include "cfg.h"
#include "basic-block.h"
#include "tree-ssa-alias.h"
#include "internal-fn.h"
#include "gimple-expr.h"
#include "is-a.h"
#include "gimple.h"
#include "gimple-ssa.h"
#include "hash-map.h"
#include "plugin-api.h"
#include "ipa-ref.h"
#include "cgraph.h"
#include "tree-ssanames.h"
#include "target.h"
#include "common/common-target.h"
#include "timevar.h"
#include "df.h"
#include "diagnostic.h"
#include "tree-ssa-live.h"
#include "tree-outof-ssa.h"
#include "target-globals.h"
#include "params.h"
#include "tree-ssa-address.h"
#include "cfgexpand.h"
#include "builtins.h"

#ifndef STACK_PUSH_CODE
#ifdef STACK_GROWS_DOWNWARD
#define STACK_PUSH_CODE PRE_DEC
#else
#define STACK_PUSH_CODE PRE_INC
#endif
#endif


/* If this is nonzero, we do not bother generating VOLATILE
   around volatile memory references, and we are willing to
   output indirect addresses.  If cse is to follow, we reject
   indirect addresses so a useful potential cse is generated;
   if it is used only once, instruction combination will produce
   the same indirect address eventually.  */
int cse_not_expected;

/* This structure is used by move_by_pieces to describe the move to
   be performed.  */
struct move_by_pieces_d
{
  rtx to;
  rtx to_addr;
  int autinc_to;
  int explicit_inc_to;
  rtx from;
  rtx from_addr;
  int autinc_from;
  int explicit_inc_from;
  unsigned HOST_WIDE_INT len;
  HOST_WIDE_INT offset;
  int reverse;
};

/* This structure is used by store_by_pieces to describe the clear to
   be performed.  */

struct store_by_pieces_d
{
  rtx to;
  rtx to_addr;
  int autinc_to;
  int explicit_inc_to;
  unsigned HOST_WIDE_INT len;
  HOST_WIDE_INT offset;
  rtx (*constfun) (void *, HOST_WIDE_INT, machine_mode);
  void *constfundata;
  int reverse;
};

static void move_by_pieces_1 (insn_gen_fn, machine_mode,
                              struct move_by_pieces_d *);
static bool block_move_libcall_safe_for_call_parm (void);
static bool emit_block_move_via_movmem (rtx, rtx, rtx, unsigned, unsigned, HOST_WIDE_INT,
                                        unsigned HOST_WIDE_INT, unsigned HOST_WIDE_INT,
                                        unsigned HOST_WIDE_INT);
static tree emit_block_move_libcall_fn (int);
static void emit_block_move_via_loop (rtx, rtx, rtx, unsigned);
static rtx clear_by_pieces_1 (void *, HOST_WIDE_INT, machine_mode);
static void clear_by_pieces (rtx, unsigned HOST_WIDE_INT, unsigned int);
static void store_by_pieces_1 (struct store_by_pieces_d *, unsigned int);
static void store_by_pieces_2 (insn_gen_fn, machine_mode,
                               struct store_by_pieces_d *);
static tree clear_storage_libcall_fn (int);
static rtx_insn *compress_float_constant (rtx, rtx);
static rtx get_subtarget (rtx);
static void store_constructor_field (rtx, unsigned HOST_WIDE_INT,
                                     HOST_WIDE_INT, machine_mode,
                                     tree, int, alias_set_type);
static void store_constructor (tree, rtx, int, HOST_WIDE_INT);
static rtx store_field (rtx, HOST_WIDE_INT, HOST_WIDE_INT,
                        unsigned HOST_WIDE_INT, unsigned HOST_WIDE_INT,
                        machine_mode, tree, alias_set_type, bool);

static unsigned HOST_WIDE_INT highest_pow2_factor_for_target (const_tree, const_tree);

static int is_aligning_offset (const_tree, const_tree);
static void expand_operands (tree, tree, rtx, rtx*, rtx*,
                             enum expand_modifier);
static rtx reduce_to_bit_field_precision (rtx, rtx, tree);
static rtx do_store_flag (sepops, rtx, machine_mode);
#ifdef PUSH_ROUNDING
static void emit_single_push_insn (machine_mode, rtx, tree);
#endif
static void do_tablejump (rtx, machine_mode, rtx, rtx, rtx, int);
static rtx const_vector_from_tree (tree);
static void write_complex_part (rtx, rtx, bool);

/* This macro is used to determine whether move_by_pieces should be called
   to perform a structure copy.  */
#ifndef MOVE_BY_PIECES_P
#define MOVE_BY_PIECES_P(SIZE, ALIGN) \
  (move_by_pieces_ninsns (SIZE, ALIGN, MOVE_MAX_PIECES + 1) \
   < (unsigned int) MOVE_RATIO (optimize_insn_for_speed_p ()))
#endif

/* This macro is used to determine whether clear_by_pieces should be
   called to clear storage.  */
#ifndef CLEAR_BY_PIECES_P
#define CLEAR_BY_PIECES_P(SIZE, ALIGN) \
  (move_by_pieces_ninsns (SIZE, ALIGN, STORE_MAX_PIECES + 1) \
   < (unsigned int) CLEAR_RATIO (optimize_insn_for_speed_p ()))
#endif

/* This macro is used to determine whether store_by_pieces should be
   called to "memset" storage with byte values other than zero.  */
#ifndef SET_BY_PIECES_P
#define SET_BY_PIECES_P(SIZE, ALIGN) \
  (move_by_pieces_ninsns (SIZE, ALIGN, STORE_MAX_PIECES + 1) \
   < (unsigned int) SET_RATIO (optimize_insn_for_speed_p ()))
#endif

/* This macro is used to determine whether store_by_pieces should be
   called to "memcpy" storage when the source is a constant string.  */
#ifndef STORE_BY_PIECES_P
#define STORE_BY_PIECES_P(SIZE, ALIGN) \
  (move_by_pieces_ninsns (SIZE, ALIGN, STORE_MAX_PIECES + 1) \
   < (unsigned int) MOVE_RATIO (optimize_insn_for_speed_p ()))
#endif
\f
/* This is run to set up which modes can be used
   directly in memory and to initialize the block move optab.  It is run
   at the beginning of compilation and when the target is reinitialized.  */

void
init_expr_target (void)
{
  rtx insn, pat;
  machine_mode mode;
  int num_clobbers;
  rtx mem, mem1;
  rtx reg;

  /* Try indexing by frame ptr and try by stack ptr.
     It is known that on the Convex the stack ptr isn't a valid index.
     With luck, one or the other is valid on any machine.  */
  mem = gen_rtx_MEM (VOIDmode, stack_pointer_rtx);
  mem1 = gen_rtx_MEM (VOIDmode, frame_pointer_rtx);

  /* A scratch register we can modify in-place below to avoid
     useless RTL allocations.  */
  reg = gen_rtx_REG (VOIDmode, -1);

  insn = rtx_alloc (INSN);
  pat = gen_rtx_SET (VOIDmode, NULL_RTX, NULL_RTX);
  PATTERN (insn) = pat;

  for (mode = VOIDmode; (int) mode < NUM_MACHINE_MODES;
       mode = (machine_mode) ((int) mode + 1))
    {
      int regno;

      direct_load[(int) mode] = direct_store[(int) mode] = 0;
      PUT_MODE (mem, mode);
      PUT_MODE (mem1, mode);
      PUT_MODE (reg, mode);

      /* See if there is some register that can be used in this mode and
         directly loaded or stored from memory.  */

      if (mode != VOIDmode && mode != BLKmode)
        for (regno = 0; regno < FIRST_PSEUDO_REGISTER
             && (direct_load[(int) mode] == 0 || direct_store[(int) mode] == 0);
             regno++)
          {
            if (! HARD_REGNO_MODE_OK (regno, mode))
              continue;

            SET_REGNO (reg, regno);

            SET_SRC (pat) = mem;
            SET_DEST (pat) = reg;
            if (recog (pat, insn, &num_clobbers) >= 0)
              direct_load[(int) mode] = 1;

            SET_SRC (pat) = mem1;
            SET_DEST (pat) = reg;
            if (recog (pat, insn, &num_clobbers) >= 0)
              direct_load[(int) mode] = 1;

            SET_SRC (pat) = reg;
            SET_DEST (pat) = mem;
            if (recog (pat, insn, &num_clobbers) >= 0)
              direct_store[(int) mode] = 1;

            SET_SRC (pat) = reg;
            SET_DEST (pat) = mem1;
            if (recog (pat, insn, &num_clobbers) >= 0)
              direct_store[(int) mode] = 1;
          }
    }

  mem = gen_rtx_MEM (VOIDmode, gen_rtx_raw_REG (Pmode, 10000));

  for (mode = GET_CLASS_NARROWEST_MODE (MODE_FLOAT); mode != VOIDmode;
       mode = GET_MODE_WIDER_MODE (mode))
    {
      machine_mode srcmode;
      for (srcmode = GET_CLASS_NARROWEST_MODE (MODE_FLOAT); srcmode != mode;
           srcmode = GET_MODE_WIDER_MODE (srcmode))
        {
          enum insn_code ic;

          ic = can_extend_p (mode, srcmode, 0);
          if (ic == CODE_FOR_nothing)
            continue;

          PUT_MODE (mem, srcmode);

          if (insn_operand_matches (ic, 1, mem))
            float_extend_from_mem[mode][srcmode] = true;
        }
    }
}

/* This is run at the start of compiling a function.  */

void
init_expr (void)
{
  memset (&crtl->expr, 0, sizeof (crtl->expr));
}
\f
/* Copy data from FROM to TO, where the machine modes are not the same.
   Both modes may be integer, or both may be floating, or both may be
   fixed-point.
   UNSIGNEDP should be nonzero if FROM is an unsigned type.
   This causes zero-extension instead of sign-extension.  */

void
convert_move (rtx to, rtx from, int unsignedp)
{
  machine_mode to_mode = GET_MODE (to);
  machine_mode from_mode = GET_MODE (from);
  int to_real = SCALAR_FLOAT_MODE_P (to_mode);
  int from_real = SCALAR_FLOAT_MODE_P (from_mode);
  enum insn_code code;
  rtx libcall;

  /* rtx code for making an equivalent value.  */
  enum rtx_code equiv_code = (unsignedp < 0 ? UNKNOWN
                              : (unsignedp ? ZERO_EXTEND : SIGN_EXTEND));


  gcc_assert (to_real == from_real);
  gcc_assert (to_mode != BLKmode);
  gcc_assert (from_mode != BLKmode);

  /* If the source and destination are already the same, then there's
     nothing to do.  */
  if (to == from)
    return;

  /* If FROM is a SUBREG that indicates that we have already done at least
     the required extension, strip it.  We don't handle such SUBREGs as
     TO here.  */

  if (GET_CODE (from) == SUBREG && SUBREG_PROMOTED_VAR_P (from)
      && (GET_MODE_PRECISION (GET_MODE (SUBREG_REG (from)))
          >= GET_MODE_PRECISION (to_mode))
      && SUBREG_CHECK_PROMOTED_SIGN (from, unsignedp))
    from = gen_lowpart (to_mode, from), from_mode = to_mode;

  gcc_assert (GET_CODE (to) != SUBREG || !SUBREG_PROMOTED_VAR_P (to));

  if (to_mode == from_mode
      || (from_mode == VOIDmode && CONSTANT_P (from)))
    {
      emit_move_insn (to, from);
      return;
    }

  if (VECTOR_MODE_P (to_mode) || VECTOR_MODE_P (from_mode))
    {
      gcc_assert (GET_MODE_BITSIZE (from_mode) == GET_MODE_BITSIZE (to_mode));

      if (VECTOR_MODE_P (to_mode))
        from = simplify_gen_subreg (to_mode, from, GET_MODE (from), 0);
      else
        to = simplify_gen_subreg (from_mode, to, GET_MODE (to), 0);

      emit_move_insn (to, from);
      return;
    }

  if (GET_CODE (to) == CONCAT && GET_CODE (from) == CONCAT)
    {
      convert_move (XEXP (to, 0), XEXP (from, 0), unsignedp);
      convert_move (XEXP (to, 1), XEXP (from, 1), unsignedp);
      return;
    }

  if (to_real)
    {
      rtx value;
      rtx_insn *insns;
      convert_optab tab;

      gcc_assert ((GET_MODE_PRECISION (from_mode)
                   != GET_MODE_PRECISION (to_mode))
                  || (DECIMAL_FLOAT_MODE_P (from_mode)
                      != DECIMAL_FLOAT_MODE_P (to_mode)));

      if (GET_MODE_PRECISION (from_mode) == GET_MODE_PRECISION (to_mode))
        /* Conversion between decimal float and binary float, same size.  */
        tab = DECIMAL_FLOAT_MODE_P (from_mode) ? trunc_optab : sext_optab;
      else if (GET_MODE_PRECISION (from_mode) < GET_MODE_PRECISION (to_mode))
        tab = sext_optab;
      else
        tab = trunc_optab;

      /* Try converting directly if the insn is supported.  */

      code = convert_optab_handler (tab, to_mode, from_mode);
      if (code != CODE_FOR_nothing)
        {
          emit_unop_insn (code, to, from,
                          tab == sext_optab ? FLOAT_EXTEND : FLOAT_TRUNCATE);
          return;
        }

      /* Otherwise use a libcall.  */
      libcall = convert_optab_libfunc (tab, to_mode, from_mode);

      /* Is this conversion implemented yet?  */
      gcc_assert (libcall);

      start_sequence ();
      value = emit_library_call_value (libcall, NULL_RTX, LCT_CONST, to_mode,
                                       1, from, from_mode);
      insns = get_insns ();
      end_sequence ();
      emit_libcall_block (insns, to, value,
                          tab == trunc_optab ? gen_rtx_FLOAT_TRUNCATE (to_mode,
                                                                       from)
                          : gen_rtx_FLOAT_EXTEND (to_mode, from));
      return;
    }

  /* Handle pointer conversion.  */                     /* SPEE 900220.  */
  /* If the target has a converter from FROM_MODE to TO_MODE, use it.  */
  {
    convert_optab ctab;

    if (GET_MODE_PRECISION (from_mode) > GET_MODE_PRECISION (to_mode))
      ctab = trunc_optab;
    else if (unsignedp)
      ctab = zext_optab;
    else
      ctab = sext_optab;

    if (convert_optab_handler (ctab, to_mode, from_mode)
        != CODE_FOR_nothing)
      {
        emit_unop_insn (convert_optab_handler (ctab, to_mode, from_mode),
                        to, from, UNKNOWN);
        return;
      }
  }

  /* Targets are expected to provide conversion insns between PxImode and
     xImode for all MODE_PARTIAL_INT modes they use, but no others.  */
  if (GET_MODE_CLASS (to_mode) == MODE_PARTIAL_INT)
    {
      machine_mode full_mode
        = smallest_mode_for_size (GET_MODE_BITSIZE (to_mode), MODE_INT);

      gcc_assert (convert_optab_handler (trunc_optab, to_mode, full_mode)
                  != CODE_FOR_nothing);

      if (full_mode != from_mode)
        from = convert_to_mode (full_mode, from, unsignedp);
      emit_unop_insn (convert_optab_handler (trunc_optab, to_mode, full_mode),
                      to, from, UNKNOWN);
      return;
    }
  if (GET_MODE_CLASS (from_mode) == MODE_PARTIAL_INT)
    {
      rtx new_from;
      machine_mode full_mode
        = smallest_mode_for_size (GET_MODE_BITSIZE (from_mode), MODE_INT);
      convert_optab ctab = unsignedp ? zext_optab : sext_optab;
      enum insn_code icode;

      icode = convert_optab_handler (ctab, full_mode, from_mode);
      gcc_assert (icode != CODE_FOR_nothing);

      if (to_mode == full_mode)
        {
          emit_unop_insn (icode, to, from, UNKNOWN);
          return;
        }

      new_from = gen_reg_rtx (full_mode);
      emit_unop_insn (icode, new_from, from, UNKNOWN);

      /* else proceed to integer conversions below.  */
      from_mode = full_mode;
      from = new_from;
    }

   /* Make sure both are fixed-point modes or both are not.  */
   gcc_assert (ALL_SCALAR_FIXED_POINT_MODE_P (from_mode) ==
               ALL_SCALAR_FIXED_POINT_MODE_P (to_mode));
   if (ALL_SCALAR_FIXED_POINT_MODE_P (from_mode))
    {
      /* If we widen from_mode to to_mode and they are in the same class,
         we won't saturate the result.
         Otherwise, always saturate the result to play safe.  */
      if (GET_MODE_CLASS (from_mode) == GET_MODE_CLASS (to_mode)
          && GET_MODE_SIZE (from_mode) < GET_MODE_SIZE (to_mode))
        expand_fixed_convert (to, from, 0, 0);
      else
        expand_fixed_convert (to, from, 0, 1);
      return;
    }

  /* Now both modes are integers.  */

  /* Handle expanding beyond a word.  */
  if (GET_MODE_PRECISION (from_mode) < GET_MODE_PRECISION (to_mode)
      && GET_MODE_PRECISION (to_mode) > BITS_PER_WORD)
    {
      rtx_insn *insns;
      rtx lowpart;
      rtx fill_value;
      rtx lowfrom;
      int i;
      machine_mode lowpart_mode;
      int nwords = CEIL (GET_MODE_SIZE (to_mode), UNITS_PER_WORD);

      /* Try converting directly if the insn is supported.  */
      if ((code = can_extend_p (to_mode, from_mode, unsignedp))
          != CODE_FOR_nothing)
        {
          /* If FROM is a SUBREG, put it into a register.  Do this
             so that we always generate the same set of insns for
             better cse'ing; if an intermediate assignment occurred,
             we won't be doing the operation directly on the SUBREG.  */
          if (optimize > 0 && GET_CODE (from) == SUBREG)
            from = force_reg (from_mode, from);
          emit_unop_insn (code, to, from, equiv_code);
          return;
        }
      /* Next, try converting via full word.  */
      else if (GET_MODE_PRECISION (from_mode) < BITS_PER_WORD
               && ((code = can_extend_p (to_mode, word_mode, unsignedp))
                   != CODE_FOR_nothing))
        {
          rtx word_to = gen_reg_rtx (word_mode);
          if (REG_P (to))
            {
              if (reg_overlap_mentioned_p (to, from))
                from = force_reg (from_mode, from);
              emit_clobber (to);
            }
          convert_move (word_to, from, unsignedp);
          emit_unop_insn (code, to, word_to, equiv_code);
          return;
        }

      /* No special multiword conversion insn; do it by hand.  */
      start_sequence ();

      /* Since we will turn this into a no conflict block, we must ensure the
         the source does not overlap the target so force it into an isolated
         register when maybe so.  Likewise for any MEM input, since the
         conversion sequence might require several references to it and we
         must ensure we're getting the same value every time.  */

      if (MEM_P (from) || reg_overlap_mentioned_p (to, from))
        from = force_reg (from_mode, from);

      /* Get a copy of FROM widened to a word, if necessary.  */
      if (GET_MODE_PRECISION (from_mode) < BITS_PER_WORD)
        lowpart_mode = word_mode;
      else
        lowpart_mode = from_mode;

      lowfrom = convert_to_mode (lowpart_mode, from, unsignedp);

      lowpart = gen_lowpart (lowpart_mode, to);
      emit_move_insn (lowpart, lowfrom);

      /* Compute the value to put in each remaining word.  */
      if (unsignedp)
        fill_value = const0_rtx;
      else
        fill_value = emit_store_flag_force (gen_reg_rtx (word_mode),
                                            LT, lowfrom, const0_rtx,
                                            lowpart_mode, 0, -1);

      /* Fill the remaining words.  */
      for (i = GET_MODE_SIZE (lowpart_mode) / UNITS_PER_WORD; i < nwords; i++)
        {
          int index = (WORDS_BIG_ENDIAN ? nwords - i - 1 : i);
          rtx subword = operand_subword (to, index, 1, to_mode);

          gcc_assert (subword);

          if (fill_value != subword)
            emit_move_insn (subword, fill_value);
        }

      insns = get_insns ();
      end_sequence ();

      emit_insn (insns);
      return;
    }

  /* Truncating multi-word to a word or less.  */
  if (GET_MODE_PRECISION (from_mode) > BITS_PER_WORD
      && GET_MODE_PRECISION (to_mode) <= BITS_PER_WORD)
    {
      if (!((MEM_P (from)
             && ! MEM_VOLATILE_P (from)
             && direct_load[(int) to_mode]
             && ! mode_dependent_address_p (XEXP (from, 0),
                                            MEM_ADDR_SPACE (from)))
            || REG_P (from)
            || GET_CODE (from) == SUBREG))
        from = force_reg (from_mode, from);
      convert_move (to, gen_lowpart (word_mode, from), 0);
      return;
    }

  /* Now follow all the conversions between integers
     no more than a word long.  */

  /* For truncation, usually we can just refer to FROM in a narrower mode.  */
  if (GET_MODE_BITSIZE (to_mode) < GET_MODE_BITSIZE (from_mode)
      && TRULY_NOOP_TRUNCATION_MODES_P (to_mode, from_mode))
    {
      if (!((MEM_P (from)
             && ! MEM_VOLATILE_P (from)
             && direct_load[(int) to_mode]
             && ! mode_dependent_address_p (XEXP (from, 0),
                                            MEM_ADDR_SPACE (from)))
            || REG_P (from)
            || GET_CODE (from) == SUBREG))
        from = force_reg (from_mode, from);
      if (REG_P (from) && REGNO (from) < FIRST_PSEUDO_REGISTER
          && ! HARD_REGNO_MODE_OK (REGNO (from), to_mode))
        from = copy_to_reg (from);
      emit_move_insn (to, gen_lowpart (to_mode, from));
      return;
    }

  /* Handle extension.  */
  if (GET_MODE_PRECISION (to_mode) > GET_MODE_PRECISION (from_mode))
    {
      /* Convert directly if that works.  */
      if ((code = can_extend_p (to_mode, from_mode, unsignedp))
          != CODE_FOR_nothing)
        {
          emit_unop_insn (code, to, from, equiv_code);
          return;
        }
      else
        {
          machine_mode intermediate;
          rtx tmp;
          int shift_amount;

          /* Search for a mode to convert via.  */
          for (intermediate = from_mode; intermediate != VOIDmode;
               intermediate = GET_MODE_WIDER_MODE (intermediate))
            if (((can_extend_p (to_mode, intermediate, unsignedp)
                  != CODE_FOR_nothing)
                 || (GET_MODE_SIZE (to_mode) < GET_MODE_SIZE (intermediate)
                     && TRULY_NOOP_TRUNCATION_MODES_P (to_mode, intermediate)))
                && (can_extend_p (intermediate, from_mode, unsignedp)
                    != CODE_FOR_nothing))
              {
                convert_move (to, convert_to_mode (intermediate, from,
                                                   unsignedp), unsignedp);
                return;
              }

          /* No suitable intermediate mode.
             Generate what we need with shifts.  */
          shift_amount = (GET_MODE_PRECISION (to_mode)
                          - GET_MODE_PRECISION (from_mode));
          from = gen_lowpart (to_mode, force_reg (from_mode, from));
          tmp = expand_shift (LSHIFT_EXPR, to_mode, from, shift_amount,
                              to, unsignedp);
          tmp = expand_shift (RSHIFT_EXPR, to_mode, tmp, shift_amount,
                              to, unsignedp);
          if (tmp != to)
            emit_move_insn (to, tmp);
          return;
        }
    }

  /* Support special truncate insns for certain modes.  */
  if (convert_optab_handler (trunc_optab, to_mode,
                             from_mode) != CODE_FOR_nothing)
    {
      emit_unop_insn (convert_optab_handler (trunc_optab, to_mode, from_mode),
                      to, from, UNKNOWN);
      return;
    }

  /* Handle truncation of volatile memrefs, and so on;
     the things that couldn't be truncated directly,
     and for which there was no special instruction.

     ??? Code above formerly short-circuited this, for most integer
     mode pairs, with a force_reg in from_mode followed by a recursive
     call to this routine.  Appears always to have been wrong.  */
  if (GET_MODE_PRECISION (to_mode) < GET_MODE_PRECISION (from_mode))
    {
      rtx temp = force_reg (to_mode, gen_lowpart (to_mode, from));
      emit_move_insn (to, temp);
      return;
    }

  /* Mode combination is not recognized.  */
  gcc_unreachable ();
}

/* Return an rtx for a value that would result
   from converting X to mode MODE.
   Both X and MODE may be floating, or both integer.
   UNSIGNEDP is nonzero if X is an unsigned value.
   This can be done by referring to a part of X in place
   or by copying to a new temporary with conversion.  */

rtx
convert_to_mode (machine_mode mode, rtx x, int unsignedp)
{
  return convert_modes (mode, VOIDmode, x, unsignedp);
}

/* Return an rtx for a value that would result
   from converting X from mode OLDMODE to mode MODE.
   Both modes may be floating, or both integer.
   UNSIGNEDP is nonzero if X is an unsigned value.

   This can be done by referring to a part of X in place
   or by copying to a new temporary with conversion.

   You can give VOIDmode for OLDMODE, if you are sure X has a nonvoid mode.  */

rtx
convert_modes (machine_mode mode, machine_mode oldmode, rtx x, int unsignedp)
{
  rtx temp;

  /* If FROM is a SUBREG that indicates that we have already done at least
     the required extension, strip it.  */

  if (GET_CODE (x) == SUBREG && SUBREG_PROMOTED_VAR_P (x)
      && GET_MODE_SIZE (GET_MODE (SUBREG_REG (x))) >= GET_MODE_SIZE (mode)
      && SUBREG_CHECK_PROMOTED_SIGN (x, unsignedp))
    x = gen_lowpart (mode, SUBREG_REG (x));

  if (GET_MODE (x) != VOIDmode)
    oldmode = GET_MODE (x);

  if (mode == oldmode)
    return x;

  if (CONST_SCALAR_INT_P (x) && GET_MODE_CLASS (mode) == MODE_INT)
    {
      /* If the caller did not tell us the old mode, then there is not
         much to do with respect to canonicalization.  We have to
         assume that all the bits are significant.  */
      if (GET_MODE_CLASS (oldmode) != MODE_INT)
        oldmode = MAX_MODE_INT;
      wide_int w = wide_int::from (std::make_pair (x, oldmode),
                                   GET_MODE_PRECISION (mode),
                                   unsignedp ? UNSIGNED : SIGNED);
      return immed_wide_int_const (w, mode);
    }

  /* We can do this with a gen_lowpart if both desired and current modes
     are integer, and this is either a constant integer, a register, or a
     non-volatile MEM. */
  if (GET_MODE_CLASS (mode) == MODE_INT
      && GET_MODE_CLASS (oldmode) == MODE_INT
      && GET_MODE_PRECISION (mode) <= GET_MODE_PRECISION (oldmode)
      && ((MEM_P (x) && !MEM_VOLATILE_P (x) && direct_load[(int) mode])
          || (REG_P (x)
              && (!HARD_REGISTER_P (x)
                  || HARD_REGNO_MODE_OK (REGNO (x), mode))
              && TRULY_NOOP_TRUNCATION_MODES_P (mode, GET_MODE (x)))))

   return gen_lowpart (mode, x);

  /* Converting from integer constant into mode is always equivalent to an
     subreg operation.  */
  if (VECTOR_MODE_P (mode) && GET_MODE (x) == VOIDmode)
    {
      gcc_assert (GET_MODE_BITSIZE (mode) == GET_MODE_BITSIZE (oldmode));
      return simplify_gen_subreg (mode, x, oldmode, 0);
    }

  temp = gen_reg_rtx (mode);
  convert_move (temp, x, unsignedp);
  return temp;
}
\f
/* Return the largest alignment we can use for doing a move (or store)
   of MAX_PIECES.  ALIGN is the largest alignment we could use.  */

static unsigned int
alignment_for_piecewise_move (unsigned int max_pieces, unsigned int align)
{
  machine_mode tmode;

  tmode = mode_for_size (max_pieces * BITS_PER_UNIT, MODE_INT, 1);
  if (align >= GET_MODE_ALIGNMENT (tmode))
    align = GET_MODE_ALIGNMENT (tmode);
  else
    {
      machine_mode tmode, xmode;

      for (tmode = GET_CLASS_NARROWEST_MODE (MODE_INT), xmode = tmode;
           tmode != VOIDmode;
           xmode = tmode, tmode = GET_MODE_WIDER_MODE (tmode))
        if (GET_MODE_SIZE (tmode) > max_pieces
            || SLOW_UNALIGNED_ACCESS (tmode, align))
          break;

      align = MAX (align, GET_MODE_ALIGNMENT (xmode));
    }

  return align;
}

/* Return the widest integer mode no wider than SIZE.  If no such mode
   can be found, return VOIDmode.  */

static machine_mode
widest_int_mode_for_size (unsigned int size)
{
  machine_mode tmode, mode = VOIDmode;

  for (tmode = GET_CLASS_NARROWEST_MODE (MODE_INT);
       tmode != VOIDmode; tmode = GET_MODE_WIDER_MODE (tmode))
    if (GET_MODE_SIZE (tmode) < size)
      mode = tmode;

  return mode;
}

/* STORE_MAX_PIECES is the number of bytes at a time that we can
   store efficiently.  Due to internal GCC limitations, this is
   MOVE_MAX_PIECES limited by the number of bytes GCC can represent
   for an immediate constant.  */

#define STORE_MAX_PIECES  MIN (MOVE_MAX_PIECES, 2 * sizeof (HOST_WIDE_INT))

/* Determine whether the LEN bytes can be moved by using several move
   instructions.  Return nonzero if a call to move_by_pieces should
   succeed.  */

int
can_move_by_pieces (unsigned HOST_WIDE_INT len ATTRIBUTE_UNUSED,
                    unsigned int align ATTRIBUTE_UNUSED)
{
  return MOVE_BY_PIECES_P (len, align);
}

/* Generate several move instructions to copy LEN bytes from block FROM to
   block TO.  (These are MEM rtx's with BLKmode).

   If PUSH_ROUNDING is defined and TO is NULL, emit_single_push_insn is
   used to push FROM to the stack.

   ALIGN is maximum stack alignment we can assume.

   If ENDP is 0 return to, if ENDP is 1 return memory at the end ala
   mempcpy, and if ENDP is 2 return memory the end minus one byte ala
   stpcpy.  */

rtx
move_by_pieces (rtx to, rtx from, unsigned HOST_WIDE_INT len,
                unsigned int align, int endp)
{
  struct move_by_pieces_d data;
  machine_mode to_addr_mode;
  machine_mode from_addr_mode = get_address_mode (from);
  rtx to_addr, from_addr = XEXP (from, 0);
  unsigned int max_size = MOVE_MAX_PIECES + 1;
  enum insn_code icode;

  align = MIN (to ? MEM_ALIGN (to) : align, MEM_ALIGN (from));

  data.offset = 0;
  data.from_addr = from_addr;
  if (to)
    {
      to_addr_mode = get_address_mode (to);
      to_addr = XEXP (to, 0);
      data.to = to;
      data.autinc_to
        = (GET_CODE (to_addr) == PRE_INC || GET_CODE (to_addr) == PRE_DEC
           || GET_CODE (to_addr) == POST_INC || GET_CODE (to_addr) == POST_DEC);
      data.reverse
        = (GET_CODE (to_addr) == PRE_DEC || GET_CODE (to_addr) == POST_DEC);
    }
  else
    {
      to_addr_mode = VOIDmode;
      to_addr = NULL_RTX;
      data.to = NULL_RTX;
      data.autinc_to = 1;
#ifdef STACK_GROWS_DOWNWARD
      data.reverse = 1;
#else
      data.reverse = 0;
#endif
    }
  data.to_addr = to_addr;
  data.from = from;
  data.autinc_from
    = (GET_CODE (from_addr) == PRE_INC || GET_CODE (from_addr) == PRE_DEC
       || GET_CODE (from_addr) == POST_INC
       || GET_CODE (from_addr) == POST_DEC);

  data.explicit_inc_from = 0;
  data.explicit_inc_to = 0;
  if (data.reverse) data.offset = len;
  data.len = len;

  /* If copying requires more than two move insns,
     copy addresses to registers (to make displacements shorter)
     and use post-increment if available.  */
  if (!(data.autinc_from && data.autinc_to)
      && move_by_pieces_ninsns (len, align, max_size) > 2)
    {
      /* Find the mode of the largest move...
         MODE might not be used depending on the definitions of the
         USE_* macros below.  */
      machine_mode mode ATTRIBUTE_UNUSED
        = widest_int_mode_for_size (max_size);

      if (USE_LOAD_PRE_DECREMENT (mode) && data.reverse && ! data.autinc_from)
        {
          data.from_addr = copy_to_mode_reg (from_addr_mode,
                                             plus_constant (from_addr_mode,
                                                            from_addr, len));
          data.autinc_from = 1;
          data.explicit_inc_from = -1;
        }
      if (USE_LOAD_POST_INCREMENT (mode) && ! data.autinc_from)
        {
          data.from_addr = copy_to_mode_reg (from_addr_mode, from_addr);
          data.autinc_from = 1;
          data.explicit_inc_from = 1;
        }
      if (!data.autinc_from && CONSTANT_P (from_addr))
        data.from_addr = copy_to_mode_reg (from_addr_mode, from_addr);
      if (USE_STORE_PRE_DECREMENT (mode) && data.reverse && ! data.autinc_to)
        {
          data.to_addr = copy_to_mode_reg (to_addr_mode,
                                           plus_constant (to_addr_mode,
                                                          to_addr, len));
          data.autinc_to = 1;
          data.explicit_inc_to = -1;
        }
      if (USE_STORE_POST_INCREMENT (mode) && ! data.reverse && ! data.autinc_to)
        {
          data.to_addr = copy_to_mode_reg (to_addr_mode, to_addr);
          data.autinc_to = 1;
          data.explicit_inc_to = 1;
        }
      if (!data.autinc_to && CONSTANT_P (to_addr))
        data.to_addr = copy_to_mode_reg (to_addr_mode, to_addr);
    }

  align = alignment_for_piecewise_move (MOVE_MAX_PIECES, align);

  /* First move what we can in the largest integer mode, then go to
     successively smaller modes.  */

  while (max_size > 1 && data.len > 0)
    {
      machine_mode mode = widest_int_mode_for_size (max_size);

      if (mode == VOIDmode)
        break;

      icode = optab_handler (mov_optab, mode);
      if (icode != CODE_FOR_nothing && align >= GET_MODE_ALIGNMENT (mode))
        move_by_pieces_1 (GEN_FCN (icode), mode, &data);

      max_size = GET_MODE_SIZE (mode);
    }

  /* The code above should have handled everything.  */
  gcc_assert (!data.len);

  if (endp)
    {
      rtx to1;

      gcc_assert (!data.reverse);
      if (data.autinc_to)
        {
          if (endp == 2)
            {
              if (HAVE_POST_INCREMENT && data.explicit_inc_to > 0)
                emit_insn (gen_add2_insn (data.to_addr, constm1_rtx));
              else
                data.to_addr = copy_to_mode_reg (to_addr_mode,
                                                 plus_constant (to_addr_mode,
                                                                data.to_addr,
                                                                -1));
            }
          to1 = adjust_automodify_address (data.to, QImode, data.to_addr,
                                           data.offset);
        }
      else
        {
          if (endp == 2)
            --data.offset;
          to1 = adjust_address (data.to, QImode, data.offset);
        }
      return to1;
    }
  else
    return data.to;
}

/* Return number of insns required to move L bytes by pieces.
   ALIGN (in bits) is maximum alignment we can assume.  */

unsigned HOST_WIDE_INT
move_by_pieces_ninsns (unsigned HOST_WIDE_INT l, unsigned int align,
                       unsigned int max_size)
{
  unsigned HOST_WIDE_INT n_insns = 0;

  align = alignment_for_piecewise_move (MOVE_MAX_PIECES, align);

  while (max_size > 1 && l > 0)
    {
      machine_mode mode;
      enum insn_code icode;

      mode = widest_int_mode_for_size (max_size);

      if (mode == VOIDmode)
        break;

      icode = optab_handler (mov_optab, mode);
      if (icode != CODE_FOR_nothing && align >= GET_MODE_ALIGNMENT (mode))
        n_insns += l / GET_MODE_SIZE (mode), l %= GET_MODE_SIZE (mode);

      max_size = GET_MODE_SIZE (mode);
    }

  gcc_assert (!l);
  return n_insns;
}

/* Subroutine of move_by_pieces.  Move as many bytes as appropriate
   with move instructions for mode MODE.  GENFUN is the gen_... function
   to make a move insn for that mode.  DATA has all the other info.  */

static void
move_by_pieces_1 (insn_gen_fn genfun, machine_mode mode,
                  struct move_by_pieces_d *data)
{
  unsigned int size = GET_MODE_SIZE (mode);
  rtx to1 = NULL_RTX, from1;

  while (data->len >= size)
    {
      if (data->reverse)
        data->offset -= size;

      if (data->to)
        {
          if (data->autinc_to)
            to1 = adjust_automodify_address (data->to, mode, data->to_addr,
                                             data->offset);
          else
            to1 = adjust_address (data->to, mode, data->offset);
        }

      if (data->autinc_from)
        from1 = adjust_automodify_address (data->from, mode, data->from_addr,
                                           data->offset);
      else
        from1 = adjust_address (data->from, mode, data->offset);

      if (HAVE_PRE_DECREMENT && data->explicit_inc_to < 0)
        emit_insn (gen_add2_insn (data->to_addr,
                                  gen_int_mode (-(HOST_WIDE_INT) size,
                                                GET_MODE (data->to_addr))));
      if (HAVE_PRE_DECREMENT && data->explicit_inc_from < 0)
        emit_insn (gen_add2_insn (data->from_addr,
                                  gen_int_mode (-(HOST_WIDE_INT) size,
                                                GET_MODE (data->from_addr))));

      if (data->to)
        emit_insn ((*genfun) (to1, from1));
      else
        {
#ifdef PUSH_ROUNDING
          emit_single_push_insn (mode, from1, NULL);
#else
          gcc_unreachable ();
#endif
        }

      if (HAVE_POST_INCREMENT && data->explicit_inc_to > 0)
        emit_insn (gen_add2_insn (data->to_addr,
                                  gen_int_mode (size,
                                                GET_MODE (data->to_addr))));
      if (HAVE_POST_INCREMENT && data->explicit_inc_from > 0)
        emit_insn (gen_add2_insn (data->from_addr,
                                  gen_int_mode (size,
                                                GET_MODE (data->from_addr))));

      if (! data->reverse)
        data->offset += size;

      data->len -= size;
    }
}
\f
/* Emit code to move a block Y to a block X.  This may be done with
   string-move instructions, with multiple scalar move instructions,
   or with a library call.

   Both X and Y must be MEM rtx's (perhaps inside VOLATILE) with mode BLKmode.
   SIZE is an rtx that says how long they are.
   ALIGN is the maximum alignment we can assume they have.
   METHOD describes what kind of copy this is, and what mechanisms may be used.
   MIN_SIZE is the minimal size of block to move
   MAX_SIZE is the maximal size of block to move, if it can not be represented
   in unsigned HOST_WIDE_INT, than it is mask of all ones.

   Return the address of the new block, if memcpy is called and returns it,
   0 otherwise.  */

rtx
emit_block_move_hints (rtx x, rtx y, rtx size, enum block_op_methods method,
                       unsigned int expected_align, HOST_WIDE_INT expected_size,
                       unsigned HOST_WIDE_INT min_size,
                       unsigned HOST_WIDE_INT max_size,
                       unsigned HOST_WIDE_INT probable_max_size)
{
  bool may_use_call;
  rtx retval = 0;
  unsigned int align;

  gcc_assert (size);
  if (CONST_INT_P (size)
      && INTVAL (size) == 0)
    return 0;

  switch (method)
    {
    case BLOCK_OP_NORMAL:
    case BLOCK_OP_TAILCALL:
      may_use_call = true;
      break;

    case BLOCK_OP_CALL_PARM:
      may_use_call = block_move_libcall_safe_for_call_parm ();

      /* Make inhibit_defer_pop nonzero around the library call
         to force it to pop the arguments right away.  */
      NO_DEFER_POP;
      break;

    case BLOCK_OP_NO_LIBCALL:
      may_use_call = false;
      break;

    default:
      gcc_unreachable ();
    }

  gcc_assert (MEM_P (x) && MEM_P (y));
  align = MIN (MEM_ALIGN (x), MEM_ALIGN (y));
  gcc_assert (align >= BITS_PER_UNIT);

  /* Make sure we've got BLKmode addresses; store_one_arg can decide that
     block copy is more efficient for other large modes, e.g. DCmode.  */
  x = adjust_address (x, BLKmode, 0);
  y = adjust_address (y, BLKmode, 0);

  /* Set MEM_SIZE as appropriate for this block copy.  The main place this
     can be incorrect is coming from __builtin_memcpy.  */
  if (CONST_INT_P (size))
    {
      x = shallow_copy_rtx (x);
      y = shallow_copy_rtx (y);
      set_mem_size (x, INTVAL (size));
      set_mem_size (y, INTVAL (size));
    }

  if (CONST_INT_P (size) && MOVE_BY_PIECES_P (INTVAL (size), align))
    move_by_pieces (x, y, INTVAL (size), align, 0);
  else if (emit_block_move_via_movmem (x, y, size, align,
                                       expected_align, expected_size,
                                       min_size, max_size, probable_max_size))
    ;
  else if (may_use_call
           && ADDR_SPACE_GENERIC_P (MEM_ADDR_SPACE (x))
           && ADDR_SPACE_GENERIC_P (MEM_ADDR_SPACE (y)))
    {
      /* Since x and y are passed to a libcall, mark the corresponding
         tree EXPR as addressable.  */
      tree y_expr = MEM_EXPR (y);
      tree x_expr = MEM_EXPR (x);
      if (y_expr)
        mark_addressable (y_expr);
      if (x_expr)
        mark_addressable (x_expr);
      retval = emit_block_move_via_libcall (x, y, size,
                                            method == BLOCK_OP_TAILCALL);
    }

  else
    emit_block_move_via_loop (x, y, size, align);

  if (method == BLOCK_OP_CALL_PARM)
    OK_DEFER_POP;

  return retval;
}

rtx
emit_block_move (rtx x, rtx y, rtx size, enum block_op_methods method)
{
  unsigned HOST_WIDE_INT max, min = 0;
  if (GET_CODE (size) == CONST_INT)
    min = max = UINTVAL (size);
  else
    max = GET_MODE_MASK (GET_MODE (size));
  return emit_block_move_hints (x, y, size, method, 0, -1,
                                min, max, max);
}

/* A subroutine of emit_block_move.  Returns true if calling the
   block move libcall will not clobber any parameters which may have
   already been placed on the stack.  */

static bool
block_move_libcall_safe_for_call_parm (void)
{
#if defined (REG_PARM_STACK_SPACE)
  tree fn;
#endif

  /* If arguments are pushed on the stack, then they're safe.  */
  if (PUSH_ARGS)
    return true;

  /* If registers go on the stack anyway, any argument is sure to clobber
     an outgoing argument.  */
#if defined (REG_PARM_STACK_SPACE)
  fn = emit_block_move_libcall_fn (false);
  /* Avoid set but not used warning if *REG_PARM_STACK_SPACE doesn't
     depend on its argument.  */
  (void) fn;
  if (OUTGOING_REG_PARM_STACK_SPACE ((!fn ? NULL_TREE : TREE_TYPE (fn)))
      && REG_PARM_STACK_SPACE (fn) != 0)
    return false;
#endif

  /* If any argument goes in memory, then it might clobber an outgoing
     argument.  */
  {
    CUMULATIVE_ARGS args_so_far_v;
    cumulative_args_t args_so_far;
    tree fn, arg;

    fn = emit_block_move_libcall_fn (false);
    INIT_CUMULATIVE_ARGS (args_so_far_v, TREE_TYPE (fn), NULL_RTX, 0, 3);
    args_so_far = pack_cumulative_args (&args_so_far_v);

    arg = TYPE_ARG_TYPES (TREE_TYPE (fn));
    for ( ; arg != void_list_node ; arg = TREE_CHAIN (arg))
      {
        machine_mode mode = TYPE_MODE (TREE_VALUE (arg));
        rtx tmp = targetm.calls.function_arg (args_so_far, mode,
                                              NULL_TREE, true);
        if (!tmp || !REG_P (tmp))
          return false;
        if (targetm.calls.arg_partial_bytes (args_so_far, mode, NULL, 1))
          return false;
        targetm.calls.function_arg_advance (args_so_far, mode,
                                            NULL_TREE, true);
      }
  }
  return true;
}

/* A subroutine of emit_block_move.  Expand a movmem pattern;
   return true if successful.  */

static bool
emit_block_move_via_movmem (rtx x, rtx y, rtx size, unsigned int align,
                            unsigned int expected_align, HOST_WIDE_INT expected_size,
                            unsigned HOST_WIDE_INT min_size,
                            unsigned HOST_WIDE_INT max_size,
                            unsigned HOST_WIDE_INT probable_max_size)
{
  int save_volatile_ok = volatile_ok;
  machine_mode mode;

  if (expected_align < align)
    expected_align = align;
  if (expected_size != -1)
    {
      if ((unsigned HOST_WIDE_INT)expected_size > probable_max_size)
        expected_size = probable_max_size;
      if ((unsigned HOST_WIDE_INT)expected_size < min_size)
        expected_size = min_size;
    }

  /* Since this is a move insn, we don't care about volatility.  */
  volatile_ok = 1;

  /* Try the most limited insn first, because there's no point
     including more than one in the machine description unless
     the more limited one has some advantage.  */

  for (mode = GET_CLASS_NARROWEST_MODE (MODE_INT); mode != VOIDmode;
       mode = GET_MODE_WIDER_MODE (mode))
    {
      enum insn_code code = direct_optab_handler (movmem_optab, mode);

      if (code != CODE_FOR_nothing
          /* We don't need MODE to be narrower than BITS_PER_HOST_WIDE_INT
             here because if SIZE is less than the mode mask, as it is
             returned by the macro, it will definitely be less than the
             actual mode mask.  Since SIZE is within the Pmode address
             space, we limit MODE to Pmode.  */
          && ((CONST_INT_P (size)
               && ((unsigned HOST_WIDE_INT) INTVAL (size)
                   <= (GET_MODE_MASK (mode) >> 1)))
              || max_size <= (GET_MODE_MASK (mode) >> 1)
              || GET_MODE_BITSIZE (mode) >= GET_MODE_BITSIZE (Pmode)))
        {
          struct expand_operand ops[9];
          unsigned int nops;

          /* ??? When called via emit_block_move_for_call, it'd be
             nice if there were some way to inform the backend, so
             that it doesn't fail the expansion because it thinks
             emitting the libcall would be more efficient.  */
          nops = insn_data[(int) code].n_generator_args;
          gcc_assert (nops == 4 || nops == 6 || nops == 8 || nops == 9);

          create_fixed_operand (&ops[0], x);
          create_fixed_operand (&ops[1], y);
          /* The check above guarantees that this size conversion is valid.  */
          create_convert_operand_to (&ops[2], size, mode, true);
          create_integer_operand (&ops[3], align / BITS_PER_UNIT);
          if (nops >= 6)
            {
              create_integer_operand (&ops[4], expected_align / BITS_PER_UNIT);
              create_integer_operand (&ops[5], expected_size);
            }
          if (nops >= 8)
            {
              create_integer_operand (&ops[6], min_size);
              /* If we can not represent the maximal size,
                 make parameter NULL.  */
              if ((HOST_WIDE_INT) max_size != -1)
                create_integer_operand (&ops[7], max_size);
              else
                create_fixed_operand (&ops[7], NULL);
            }
          if (nops == 9)
            {
              /* If we can not represent the maximal size,
                 make parameter NULL.  */
              if ((HOST_WIDE_INT) probable_max_size != -1)
                create_integer_operand (&ops[8], probable_max_size);
              else
                create_fixed_operand (&ops[8], NULL);
            }
          if (maybe_expand_insn (code, nops, ops))
            {
              volatile_ok = save_volatile_ok;
              return true;
            }
        }
    }

  volatile_ok = save_volatile_ok;
  return false;
}

/* A subroutine of emit_block_move.  Expand a call to memcpy.
   Return the return value from memcpy, 0 otherwise.  */

rtx
emit_block_move_via_libcall (rtx dst, rtx src, rtx size, bool tailcall)
{
  rtx dst_addr, src_addr;
  tree call_expr, fn, src_tree, dst_tree, size_tree;
  machine_mode size_mode;
  rtx retval;

  /* Emit code to copy the addresses of DST and SRC and SIZE into new
     pseudos.  We can then place those new pseudos into a VAR_DECL and
     use them later.  */

  dst_addr = copy_addr_to_reg (XEXP (dst, 0));
  src_addr = copy_addr_to_reg (XEXP (src, 0));

  dst_addr = convert_memory_address (ptr_mode, dst_addr);
  src_addr = convert_memory_address (ptr_mode, src_addr);

  dst_tree = make_tree (ptr_type_node, dst_addr);
  src_tree = make_tree (ptr_type_node, src_addr);

  size_mode = TYPE_MODE (sizetype);

  size = convert_to_mode (size_mode, size, 1);
  size = copy_to_mode_reg (size_mode, size);

  /* It is incorrect to use the libcall calling conventions to call
     memcpy in this context.  This could be a user call to memcpy and
     the user may wish to examine the return value from memcpy.  For
     targets where libcalls and normal calls have different conventions
     for returning pointers, we could end up generating incorrect code.  */

  size_tree = make_tree (sizetype, size);

  fn = emit_block_move_libcall_fn (true);
  call_expr = build_call_expr (fn, 3, dst_tree, src_tree, size_tree);
  CALL_EXPR_TAILCALL (call_expr) = tailcall;

  retval = expand_normal (call_expr);

  return retval;
}

/* A subroutine of emit_block_move_via_libcall.  Create the tree node
   for the function we use for block copies.  */

static GTY(()) tree block_move_fn;

void
init_block_move_fn (const char *asmspec)
{
  if (!block_move_fn)
    {
      tree args, fn, attrs, attr_args;

      fn = get_identifier ("memcpy");
      args = build_function_type_list (ptr_type_node, ptr_type_node,
                                       const_ptr_type_node, sizetype,
                                       NULL_TREE);

      fn = build_decl (UNKNOWN_LOCATION, FUNCTION_DECL, fn, args);
      DECL_EXTERNAL (fn) = 1;
      TREE_PUBLIC (fn) = 1;
      DECL_ARTIFICIAL (fn) = 1;
      TREE_NOTHROW (fn) = 1;
      DECL_VISIBILITY (fn) = VISIBILITY_DEFAULT;
      DECL_VISIBILITY_SPECIFIED (fn) = 1;

      attr_args = build_tree_list (NULL_TREE, build_string (1, "1"));
      attrs = tree_cons (get_identifier ("fn spec"), attr_args, NULL);

      decl_attributes (&fn, attrs, ATTR_FLAG_BUILT_IN);

      block_move_fn = fn;
    }

  if (asmspec)
    set_user_assembler_name (block_move_fn, asmspec);
}

static tree
emit_block_move_libcall_fn (int for_call)
{
  static bool emitted_extern;

  if (!block_move_fn)
    init_block_move_fn (NULL);

  if (for_call && !emitted_extern)
    {
      emitted_extern = true;
      make_decl_rtl (block_move_fn);
    }

  return block_move_fn;
}

/* A subroutine of emit_block_move.  Copy the data via an explicit
   loop.  This is used only when libcalls are forbidden.  */
/* ??? It'd be nice to copy in hunks larger than QImode.  */

static void
emit_block_move_via_loop (rtx x, rtx y, rtx size,
                          unsigned int align ATTRIBUTE_UNUSED)
{
  rtx_code_label *cmp_label, *top_label;
  rtx iter, x_addr, y_addr, tmp;
  machine_mode x_addr_mode = get_address_mode (x);
  machine_mode y_addr_mode = get_address_mode (y);
  machine_mode iter_mode;

  iter_mode = GET_MODE (size);
  if (iter_mode == VOIDmode)
    iter_mode = word_mode;

  top_label = gen_label_rtx ();
  cmp_label = gen_label_rtx ();
  iter = gen_reg_rtx (iter_mode);

  emit_move_insn (iter, const0_rtx);

  x_addr = force_operand (XEXP (x, 0), NULL_RTX);
  y_addr = force_operand (XEXP (y, 0), NULL_RTX);
  do_pending_stack_adjust ();

  emit_jump (cmp_label);
  emit_label (top_label);

  tmp = convert_modes (x_addr_mode, iter_mode, iter, true);
  x_addr = simplify_gen_binary (PLUS, x_addr_mode, x_addr, tmp);

  if (x_addr_mode != y_addr_mode)
    tmp = convert_modes (y_addr_mode, iter_mode, iter, true);
  y_addr = simplify_gen_binary (PLUS, y_addr_mode, y_addr, tmp);

  x = change_address (x, QImode, x_addr);
  y = change_address (y, QImode, y_addr);

  emit_move_insn (x, y);

  tmp = expand_simple_binop (iter_mode, PLUS, iter, const1_rtx, iter,
                             true, OPTAB_LIB_WIDEN);
  if (tmp != iter)
    emit_move_insn (iter, tmp);

  emit_label (cmp_label);

  emit_cmp_and_jump_insns (iter, size, LT, NULL_RTX, iter_mode,
                           true, top_label, REG_BR_PROB_BASE * 90 / 100);
}
\f
/* Copy all or part of a value X into registers starting at REGNO.
   The number of registers to be filled is NREGS.  */

void
move_block_to_reg (int regno, rtx x, int nregs, machine_mode mode)
{
  int i;
#ifdef HAVE_load_multiple
  rtx pat;
  rtx_insn *last;
#endif

  if (nregs == 0)
    return;

  if (CONSTANT_P (x) && !targetm.legitimate_constant_p (mode, x))
    x = validize_mem (force_const_mem (mode, x));

  /* See if the machine can do this with a load multiple insn.  */
#ifdef HAVE_load_multiple
  if (HAVE_load_multiple)
    {
      last = get_last_insn ();
      pat = gen_load_multiple (gen_rtx_REG (word_mode, regno), x,
                               GEN_INT (nregs));
      if (pat)
        {
          emit_insn (pat);
          return;
        }
      else
        delete_insns_since (last);
    }
#endif

  for (i = 0; i < nregs; i++)
    emit_move_insn (gen_rtx_REG (word_mode, regno + i),
                    operand_subword_force (x, i, mode));
}

/* Copy all or part of a BLKmode value X out of registers starting at REGNO.
   The number of registers to be filled is NREGS.  */

void
move_block_from_reg (int regno, rtx x, int nregs)
{
  int i;

  if (nregs == 0)
    return;

  /* See if the machine can do this with a store multiple insn.  */
#ifdef HAVE_store_multiple
  if (HAVE_store_multiple)
    {
      rtx_insn *last = get_last_insn ();
      rtx pat = gen_store_multiple (x, gen_rtx_REG (word_mode, regno),
                                    GEN_INT (nregs));
      if (pat)
        {
          emit_insn (pat);
          return;
        }
      else
        delete_insns_since (last);
    }
#endif

  for (i = 0; i < nregs; i++)
    {
      rtx tem = operand_subword (x, i, 1, BLKmode);

      gcc_assert (tem);

      emit_move_insn (tem, gen_rtx_REG (word_mode, regno + i));
    }
}

/* Generate a PARALLEL rtx for a new non-consecutive group of registers from
   ORIG, where ORIG is a non-consecutive group of registers represented by
   a PARALLEL.  The clone is identical to the original except in that the
   original set of registers is replaced by a new set of pseudo registers.
   The new set has the same modes as the original set.  */

rtx
gen_group_rtx (rtx orig)
{
  int i, length;
  rtx *tmps;

  gcc_assert (GET_CODE (orig) == PARALLEL);

  length = XVECLEN (orig, 0);
  tmps = XALLOCAVEC (rtx, length);

  /* Skip a NULL entry in first slot.  */
  i = XEXP (XVECEXP (orig, 0, 0), 0) ? 0 : 1;

  if (i)
    tmps[0] = 0;

  for (; i < length; i++)
    {
      machine_mode mode = GET_MODE (XEXP (XVECEXP (orig, 0, i), 0));
      rtx offset = XEXP (XVECEXP (orig, 0, i), 1);

      tmps[i] = gen_rtx_EXPR_LIST (VOIDmode, gen_reg_rtx (mode), offset);
    }

  return gen_rtx_PARALLEL (GET_MODE (orig), gen_rtvec_v (length, tmps));
}

/* A subroutine of emit_group_load.  Arguments as for emit_group_load,
   except that values are placed in TMPS[i], and must later be moved
   into corresponding XEXP (XVECEXP (DST, 0, i), 0) element.  */

static void
emit_group_load_1 (rtx *tmps, rtx dst, rtx orig_src, tree type, int ssize)
{
  rtx src;
  int start, i;
  machine_mode m = GET_MODE (orig_src);

  gcc_assert (GET_CODE (dst) == PARALLEL);

  if (m != VOIDmode
      && !SCALAR_INT_MODE_P (m)
      && !MEM_P (orig_src)
      && GET_CODE (orig_src) != CONCAT)
    {
      machine_mode imode = int_mode_for_mode (GET_MODE (orig_src));
      if (imode == BLKmode)
        src = assign_stack_temp (GET_MODE (orig_src), ssize);
      else
        src = gen_reg_rtx (imode);
      if (imode != BLKmode)
        src = gen_lowpart (GET_MODE (orig_src), src);
      emit_move_insn (src, orig_src);
      /* ...and back again.  */
      if (imode != BLKmode)
        src = gen_lowpart (imode, src);
      emit_group_load_1 (tmps, dst, src, type, ssize);
      return;
    }

  /* Check for a NULL entry, used to indicate that the parameter goes
     both on the stack and in registers.  */
  if (XEXP (XVECEXP (dst, 0, 0), 0))
    start = 0;
  else
    start = 1;

  /* Process the pieces.  */
  for (i = start; i < XVECLEN (dst, 0); i++)
    {
      machine_mode mode = GET_MODE (XEXP (XVECEXP (dst, 0, i), 0));
      HOST_WIDE_INT bytepos = INTVAL (XEXP (XVECEXP (dst, 0, i), 1));
      unsigned int bytelen = GET_MODE_SIZE (mode);
      int shift = 0;

      /* Handle trailing fragments that run over the size of the struct.  */
      if (ssize >= 0 && bytepos + (HOST_WIDE_INT) bytelen > ssize)
        {
          /* Arrange to shift the fragment to where it belongs.
             extract_bit_field loads to the lsb of the reg.  */
          if (
#ifdef BLOCK_REG_PADDING
              BLOCK_REG_PADDING (GET_MODE (orig_src), type, i == start)
              == (BYTES_BIG_ENDIAN ? upward : downward)
#else
              BYTES_BIG_ENDIAN
#endif
              )
            shift = (bytelen - (ssize - bytepos)) * BITS_PER_UNIT;
          bytelen = ssize - bytepos;
          gcc_assert (bytelen > 0);
        }

      /* If we won't be loading directly from memory, protect the real source
         from strange tricks we might play; but make sure that the source can
         be loaded directly into the destination.  */
      src = orig_src;
      if (!MEM_P (orig_src)
          && (!CONSTANT_P (orig_src)
              || (GET_MODE (orig_src) != mode
                  && GET_MODE (orig_src) != VOIDmode)))
        {
          if (GET_MODE (orig_src) == VOIDmode)
            src = gen_reg_rtx (mode);
          else
            src = gen_reg_rtx (GET_MODE (orig_src));

          emit_move_insn (src, orig_src);
        }

      /* Optimize the access just a bit.  */
      if (MEM_P (src)
          && (! SLOW_UNALIGNED_ACCESS (mode, MEM_ALIGN (src))
              || MEM_ALIGN (src) >= GET_MODE_ALIGNMENT (mode))
          && bytepos * BITS_PER_UNIT % GET_MODE_ALIGNMENT (mode) == 0
          && bytelen == GET_MODE_SIZE (mode))
        {
          tmps[i] = gen_reg_rtx (mode);
          emit_move_insn (tmps[i], adjust_address (src, mode, bytepos));
        }
      else if (COMPLEX_MODE_P (mode)
               && GET_MODE (src) == mode
               && bytelen == GET_MODE_SIZE (mode))
        /* Let emit_move_complex do the bulk of the work.  */
        tmps[i] = src;
      else if (GET_CODE (src) == CONCAT)
        {
          unsigned int slen = GET_MODE_SIZE (GET_MODE (src));
          unsigned int slen0 = GET_MODE_SIZE (GET_MODE (XEXP (src, 0)));

          if ((bytepos == 0 && bytelen == slen0)
              || (bytepos != 0 && bytepos + bytelen <= slen))
            {
              /* The following assumes that the concatenated objects all
                 have the same size.  In this case, a simple calculation
                 can be used to determine the object and the bit field
                 to be extracted.  */
              tmps[i] = XEXP (src, bytepos / slen0);
              if (! CONSTANT_P (tmps[i])
                  && (!REG_P (tmps[i]) || GET_MODE (tmps[i]) != mode))
                tmps[i] = extract_bit_field (tmps[i], bytelen * BITS_PER_UNIT,
                                             (bytepos % slen0) * BITS_PER_UNIT,
                                             1, NULL_RTX, mode, mode);
            }
          else
            {
              rtx mem;

              gcc_assert (!bytepos);
              mem = assign_stack_temp (GET_MODE (src), slen);
              emit_move_insn (mem, src);
              tmps[i] = extract_bit_field (mem, bytelen * BITS_PER_UNIT,
                                           0, 1, NULL_RTX, mode, mode);
            }
        }
      /* FIXME: A SIMD parallel will eventually lead to a subreg of a
         SIMD register, which is currently broken.  While we get GCC
         to emit proper RTL for these cases, let's dump to memory.  */
      else if (VECTOR_MODE_P (GET_MODE (dst))
               && REG_P (src))
        {
          int slen = GET_MODE_SIZE (GET_MODE (src));
          rtx mem;

          mem = assign_stack_temp (GET_MODE (src), slen);
          emit_move_insn (mem, src);
          tmps[i] = adjust_address (mem, mode, (int) bytepos);
        }
      else if (CONSTANT_P (src) && GET_MODE (dst) != BLKmode
               && XVECLEN (dst, 0) > 1)
        tmps[i] = simplify_gen_subreg (mode, src, GET_MODE (dst), bytepos);
      else if (CONSTANT_P (src))
        {
          HOST_WIDE_INT len = (HOST_WIDE_INT) bytelen;

          if (len == ssize)
            tmps[i] = src;
          else
            {
              rtx first, second;

              /* TODO: const_wide_int can have sizes other than this...  */
              gcc_assert (2 * len == ssize);
              split_double (src, &first, &second);
              if (i)
                tmps[i] = second;
              else
                tmps[i] = first;
            }
        }
      else if (REG_P (src) && GET_MODE (src) == mode)
        tmps[i] = src;
      else
        tmps[i] = extract_bit_field (src, bytelen * BITS_PER_UNIT,
                                     bytepos * BITS_PER_UNIT, 1, NULL_RTX,
                                     mode, mode);

      if (shift)
        tmps[i] = expand_shift (LSHIFT_EXPR, mode, tmps[i],
                                shift, tmps[i], 0);
    }
}

/* Emit code to move a block SRC of type TYPE to a block DST,
   where DST is non-consecutive registers represented by a PARALLEL.
   SSIZE represents the total size of block ORIG_SRC in bytes, or -1
   if not known.  */

void
emit_group_load (rtx dst, rtx src, tree type, int ssize)
{
  rtx *tmps;
  int i;

  tmps = XALLOCAVEC (rtx, XVECLEN (dst, 0));
  emit_group_load_1 (tmps, dst, src, type, ssize);

  /* Copy the extracted pieces into the proper (probable) hard regs.  */
  for (i = 0; i < XVECLEN (dst, 0); i++)
    {
      rtx d = XEXP (XVECEXP (dst, 0, i), 0);
      if (d == NULL)
        continue;
      emit_move_insn (d, tmps[i]);
    }
}

/* Similar, but load SRC into new pseudos in a format that looks like
   PARALLEL.  This can later be fed to emit_group_move to get things
   in the right place.  */

rtx
emit_group_load_into_temps (rtx parallel, rtx src, tree type, int ssize)
{
  rtvec vec;
  int i;

  vec = rtvec_alloc (XVECLEN (parallel, 0));
  emit_group_load_1 (&RTVEC_ELT (vec, 0), parallel, src, type, ssize);

  /* Convert the vector to look just like the original PARALLEL, except
     with the computed values.  */
  for (i = 0; i < XVECLEN (parallel, 0); i++)
    {
      rtx e = XVECEXP (parallel, 0, i);
      rtx d = XEXP (e, 0);

      if (d)
        {
          d = force_reg (GET_MODE (d), RTVEC_ELT (vec, i));
          e = alloc_EXPR_LIST (REG_NOTE_KIND (e), d, XEXP (e, 1));
        }
      RTVEC_ELT (vec, i) = e;
    }

  return gen_rtx_PARALLEL (GET_MODE (parallel), vec);
}

/* Emit code to move a block SRC to block DST, where SRC and DST are
   non-consecutive groups of registers, each represented by a PARALLEL.  */

void
emit_group_move (rtx dst, rtx src)
{
  int i;

  gcc_assert (GET_CODE (src) == PARALLEL
              && GET_CODE (dst) == PARALLEL
              && XVECLEN (src, 0) == XVECLEN (dst, 0));

  /* Skip first entry if NULL.  */
  for (i = XEXP (XVECEXP (src, 0, 0), 0) ? 0 : 1; i < XVECLEN (src, 0); i++)
    emit_move_insn (XEXP (XVECEXP (dst, 0, i), 0),
                    XEXP (XVECEXP (src, 0, i), 0));
}

/* Move a group of registers represented by a PARALLEL into pseudos.  */

rtx
emit_group_move_into_temps (rtx src)
{
  rtvec vec = rtvec_alloc (XVECLEN (src, 0));
  int i;

  for (i = 0; i < XVECLEN (src, 0); i++)
    {
      rtx e = XVECEXP (src, 0, i);
      rtx d = XEXP (e, 0);

      if (d)
        e = alloc_EXPR_LIST (REG_NOTE_KIND (e), copy_to_reg (d), XEXP (e, 1));
      RTVEC_ELT (vec, i) = e;
    }

  return gen_rtx_PARALLEL (GET_MODE (src), vec);
}

/* Emit code to move a block SRC to a block ORIG_DST of type TYPE,
   where SRC is non-consecutive registers represented by a PARALLEL.
   SSIZE represents the total size of block ORIG_DST, or -1 if not
   known.  */

void
emit_group_store (rtx orig_dst, rtx src, tree type ATTRIBUTE_UNUSED, int ssize)
{
  rtx *tmps, dst;
  int start, finish, i;
  machine_mode m = GET_MODE (orig_dst);

  gcc_assert (GET_CODE (src) == PARALLEL);

  if (!SCALAR_INT_MODE_P (m)
      && !MEM_P (orig_dst) && GET_CODE (orig_dst) != CONCAT)
    {
      machine_mode imode = int_mode_for_mode (GET_MODE (orig_dst));
      if (imode == BLKmode)
        dst = assign_stack_temp (GET_MODE (orig_dst), ssize);
      else
        dst = gen_reg_rtx (imode);
      emit_group_store (dst, src, type, ssize);
      if (imode != BLKmode)
        dst = gen_lowpart (GET_MODE (orig_dst), dst);
      emit_move_insn (orig_dst, dst);
      return;
    }

  /* Check for a NULL entry, used to indicate that the parameter goes
     both on the stack and in registers.  */
  if (XEXP (XVECEXP (src, 0, 0), 0))
    start = 0;
  else
    start = 1;
  finish = XVECLEN (src, 0);

  tmps = XALLOCAVEC (rtx, finish);

  /* Copy the (probable) hard regs into pseudos.  */
  for (i = start; i < finish; i++)
    {
      rtx reg = XEXP (XVECEXP (src, 0, i), 0);
      if (!REG_P (reg) || REGNO (reg) < FIRST_PSEUDO_REGISTER)
        {
          tmps[i] = gen_reg_rtx (GET_MODE (reg));
          emit_move_insn (tmps[i], reg);
        }
      else
        tmps[i] = reg;
    }

  /* If we won't be storing directly into memory, protect the real destination
     from strange tricks we might play.  */
  dst = orig_dst;
  if (GET_CODE (dst) == PARALLEL)
    {
      rtx temp;

      /* We can get a PARALLEL dst if there is a conditional expression in
         a return statement.  In that case, the dst and src are the same,
         so no action is necessary.  */
      if (rtx_equal_p (dst, src))
        return;

      /* It is unclear if we can ever reach here, but we may as well handle
         it.  Allocate a temporary, and split this into a store/load to/from
         the temporary.  */
      temp = assign_stack_temp (GET_MODE (dst), ssize);
      emit_group_store (temp, src, type, ssize);
      emit_group_load (dst, temp, type, ssize);
      return;
    }
  else if (!MEM_P (dst) && GET_CODE (dst) != CONCAT)
    {
      machine_mode outer = GET_MODE (dst);
      machine_mode inner;
      HOST_WIDE_INT bytepos;
      bool done = false;
      rtx temp;

      if (!REG_P (dst) || REGNO (dst) < FIRST_PSEUDO_REGISTER)
        dst = gen_reg_rtx (outer);

      /* Make life a bit easier for combine.  */
      /* If the first element of the vector is the low part
         of the destination mode, use a paradoxical subreg to
         initialize the destination.  */
      if (start < finish)
        {
          inner = GET_MODE (tmps[start]);
          bytepos = subreg_lowpart_offset (inner, outer);
          if (INTVAL (XEXP (XVECEXP (src, 0, start), 1)) == bytepos)
            {
              temp = simplify_gen_subreg (outer, tmps[start],
                                          inner, 0);
              if (temp)
                {
                  emit_move_insn (dst, temp);
                  done = true;
                  start++;
                }
            }
        }

      /* If the first element wasn't the low part, try the last.  */
      if (!done
          && start < finish - 1)
        {
          inner = GET_MODE (tmps[finish - 1]);
          bytepos = subreg_lowpart_offset (inner, outer);
          if (INTVAL (XEXP (XVECEXP (src, 0, finish - 1), 1)) == bytepos)
            {
              temp = simplify_gen_subreg (outer, tmps[finish - 1],
                                          inner, 0);
              if (temp)
                {
                  emit_move_insn (dst, temp);
                  done = true;
                  finish--;
                }
            }
        }

      /* Otherwise, simply initialize the result to zero.  */
      if (!done)
        emit_move_insn (dst, CONST0_RTX (outer));
    }

  /* Process the pieces.  */
  for (i = start; i < finish; i++)
    {
      HOST_WIDE_INT bytepos = INTVAL (XEXP (XVECEXP (src, 0, i), 1));
      machine_mode mode = GET_MODE (tmps[i]);
      unsigned int bytelen = GET_MODE_SIZE (mode);
      unsigned int adj_bytelen;
      rtx dest = dst;

      /* Handle trailing fragments that run over the size of the struct.  */
      if (ssize >= 0 && bytepos + (HOST_WIDE_INT) bytelen > ssize)
        adj_bytelen = ssize - bytepos;
      else
        adj_bytelen = bytelen;

      if (GET_CODE (dst) == CONCAT)
        {
          if (bytepos + adj_bytelen
              <= GET_MODE_SIZE (GET_MODE (XEXP (dst, 0))))
            dest = XEXP (dst, 0);
          else if (bytepos >= GET_MODE_SIZE (GET_MODE (XEXP (dst, 0))))
            {
              bytepos -= GET_MODE_SIZE (GET_MODE (XEXP (dst, 0)));
              dest = XEXP (dst, 1);
            }
          else
            {
              machine_mode dest_mode = GET_MODE (dest);
              machine_mode tmp_mode = GET_MODE (tmps[i]);

              gcc_assert (bytepos == 0 && XVECLEN (src, 0));

              if (GET_MODE_ALIGNMENT (dest_mode)
                  >= GET_MODE_ALIGNMENT (tmp_mode))
                {
                  dest = assign_stack_temp (dest_mode,
                                            GET_MODE_SIZE (dest_mode));
                  emit_move_insn (adjust_address (dest,
                                                  tmp_mode,
                                                  bytepos),
                                  tmps[i]);
                  dst = dest;
                }
              else
                {
                  dest = assign_stack_temp (tmp_mode,
                                            GET_MODE_SIZE (tmp_mode));
                  emit_move_insn (dest, tmps[i]);
                  dst = adjust_address (dest, dest_mode, bytepos);
                }
              break;
            }
        }

      /* Handle trailing fragments that run over the size of the struct.  */
      if (ssize >= 0 && bytepos + (HOST_WIDE_INT) bytelen > ssize)
        {
          /* store_bit_field always takes its value from the lsb.
             Move the fragment to the lsb if it's not already there.  */
          if (
#ifdef BLOCK_REG_PADDING
              BLOCK_REG_PADDING (GET_MODE (orig_dst), type, i == start)
              == (BYTES_BIG_ENDIAN ? upward : downward)
#else
              BYTES_BIG_ENDIAN
#endif
              )
            {
              int shift = (bytelen - (ssize - bytepos)) * BITS_PER_UNIT;
              tmps[i] = expand_shift (RSHIFT_EXPR, mode, tmps[i],
                                      shift, tmps[i], 0);
            }

          /* Make sure not to write past the end of the struct.  */
          store_bit_field (dest,
                           adj_bytelen * BITS_PER_UNIT, bytepos * BITS_PER_UNIT,
                           bytepos * BITS_PER_UNIT, ssize * BITS_PER_UNIT - 1,
                           VOIDmode, tmps[i]);
        }

      /* Optimize the access just a bit.  */
      else if (MEM_P (dest)
               && (!SLOW_UNALIGNED_ACCESS (mode, MEM_ALIGN (dest))
                   || MEM_ALIGN (dest) >= GET_MODE_ALIGNMENT (mode))
               && bytepos * BITS_PER_UNIT % GET_MODE_ALIGNMENT (mode) == 0
               && bytelen == GET_MODE_SIZE (mode))
        emit_move_insn (adjust_address (dest, mode, bytepos), tmps[i]);

      else
        store_bit_field (dest, bytelen * BITS_PER_UNIT, bytepos * BITS_PER_UNIT,
                         0, 0, mode, tmps[i]);
    }

  /* Copy from the pseudo into the (probable) hard reg.  */
  if (orig_dst != dst)
    emit_move_insn (orig_dst, dst);
}

/* Return a form of X that does not use a PARALLEL.  TYPE is the type
   of the value stored in X.  */

rtx
maybe_emit_group_store (rtx x, tree type)
{
  machine_mode mode = TYPE_MODE (type);
  gcc_checking_assert (GET_MODE (x) == VOIDmode || GET_MODE (x) == mode);
  if (GET_CODE (x) == PARALLEL)
    {
      rtx result = gen_reg_rtx (mode);
      emit_group_store (result, x, type, int_size_in_bytes (type));
      return result;
    }
  return x;
}

/* Copy a BLKmode object of TYPE out of a register SRCREG into TARGET.

   This is used on targets that return BLKmode values in registers.  */

void
copy_blkmode_from_reg (rtx target, rtx srcreg, tree type)
{
  unsigned HOST_WIDE_INT bytes = int_size_in_bytes (type);
  rtx src = NULL, dst = NULL;
  unsigned HOST_WIDE_INT bitsize = MIN (TYPE_ALIGN (type), BITS_PER_WORD);
  unsigned HOST_WIDE_INT bitpos, xbitpos, padding_correction = 0;
  machine_mode mode = GET_MODE (srcreg);
  machine_mode tmode = GET_MODE (target);
  machine_mode copy_mode;

  /* BLKmode registers created in the back-end shouldn't have survived.  */
  gcc_assert (mode != BLKmode);

  /* If the structure doesn't take up a whole number of words, see whether
     SRCREG is padded on the left or on the right.  If it's on the left,
     set PADDING_CORRECTION to the number of bits to skip.

     In most ABIs, the structure will be returned at the least end of
     the register, which translates to right padding on little-endian
     targets and left padding on big-endian targets.  The opposite
     holds if the structure is returned at the most significant
     end of the register.  */
  if (bytes % UNITS_PER_WORD != 0
      && (targetm.calls.return_in_msb (type)
          ? !BYTES_BIG_ENDIAN
          : BYTES_BIG_ENDIAN))
    padding_correction
      = (BITS_PER_WORD - ((bytes % UNITS_PER_WORD) * BITS_PER_UNIT));

  /* We can use a single move if we have an exact mode for the size.  */
  else if (MEM_P (target)
           && (!SLOW_UNALIGNED_ACCESS (mode, MEM_ALIGN (target))
               || MEM_ALIGN (target) >= GET_MODE_ALIGNMENT (mode))
           && bytes == GET_MODE_SIZE (mode))
  {
    emit_move_insn (adjust_address (target, mode, 0), srcreg);
    return;
  }

  /* And if we additionally have the same mode for a register.  */
  else if (REG_P (target)
           && GET_MODE (target) == mode
           && bytes == GET_MODE_SIZE (mode))
  {
    emit_move_insn (target, srcreg);
    return;
  }

  /* This code assumes srcreg is at least a full word.  If it isn't, copy it
     into a new pseudo which is a full word.  */
  if (GET_MODE_SIZE (mode) < UNITS_PER_WORD)
    {
      srcreg = convert_to_mode (word_mode, srcreg, TYPE_UNSIGNED (type));
      mode = word_mode;
    }

  /* Copy the structure BITSIZE bits at a time.  If the target lives in
     memory, take care of not reading/writing past its end by selecting
     a copy mode suited to BITSIZE.  This should always be possible given
     how it is computed.

     If the target lives in register, make sure not to select a copy mode
     larger than the mode of the register.

     We could probably emit more efficient code for machines which do not use
     strict alignment, but it doesn't seem worth the effort at the current
     time.  */

  copy_mode = word_mode;
  if (MEM_P (target))
    {
      machine_mode mem_mode = mode_for_size (bitsize, MODE_INT, 1);
      if (mem_mode != BLKmode)
        copy_mode = mem_mode;
    }
  else if (REG_P (target) && GET_MODE_BITSIZE (tmode) < BITS_PER_WORD)
    copy_mode = tmode;

  for (bitpos = 0, xbitpos = padding_correction;
       bitpos < bytes * BITS_PER_UNIT;
       bitpos += bitsize, xbitpos += bitsize)
    {
      /* We need a new source operand each time xbitpos is on a
         word boundary and when xbitpos == padding_correction
         (the first time through).  */
      if (xbitpos % BITS_PER_WORD == 0 || xbitpos == padding_correction)
        src = operand_subword_force (srcreg, xbitpos / BITS_PER_WORD, mode);

      /* We need a new destination operand each time bitpos is on
         a word boundary.  */
      if (REG_P (target) && GET_MODE_BITSIZE (tmode) < BITS_PER_WORD)
        dst = target;
      else if (bitpos % BITS_PER_WORD == 0)
        dst = operand_subword (target, bitpos / BITS_PER_WORD, 1, tmode);

      /* Use xbitpos for the source extraction (right justified) and
         bitpos for the destination store (left justified).  */
      store_bit_field (dst, bitsize, bitpos % BITS_PER_WORD, 0, 0, copy_mode,
                       extract_bit_field (src, bitsize,
                                          xbitpos % BITS_PER_WORD, 1,
                                          NULL_RTX, copy_mode, copy_mode));
    }
}

/* Copy BLKmode value SRC into a register of mode MODE.  Return the
   register if it contains any data, otherwise return null.

   This is used on targets that return BLKmode values in registers.  */

rtx
copy_blkmode_to_reg (machine_mode mode, tree src)
{
  int i, n_regs;
  unsigned HOST_WIDE_INT bitpos, xbitpos, padding_correction = 0, bytes;
  unsigned int bitsize;
  rtx *dst_words, dst, x, src_word = NULL_RTX, dst_word = NULL_RTX;
  machine_mode dst_mode;

  gcc_assert (TYPE_MODE (TREE_TYPE (src)) == BLKmode);

  x = expand_normal (src);

  bytes = int_size_in_bytes (TREE_TYPE (src));
  if (bytes == 0)
    return NULL_RTX;

  /* If the structure doesn't take up a whole number of words, see
     whether the register value should be padded on the left or on
     the right.  Set PADDING_CORRECTION to the number of padding
     bits needed on the left side.

     In most ABIs, the structure will be returned at the least end of
     the register, which translates to right padding on little-endian
     targets and left padding on big-endian targets.  The opposite
     holds if the structure is returned at the most significant
     end of the register.  */
  if (bytes % UNITS_PER_WORD != 0
      && (targetm.calls.return_in_msb (TREE_TYPE (src))
          ? !BYTES_BIG_ENDIAN
          : BYTES_BIG_ENDIAN))
    padding_correction = (BITS_PER_WORD - ((bytes % UNITS_PER_WORD)
                                           * BITS_PER_UNIT));

  n_regs = (bytes + UNITS_PER_WORD - 1) / UNITS_PER_WORD;
  dst_words = XALLOCAVEC (rtx, n_regs);
  bitsize = MIN (TYPE_ALIGN (TREE_TYPE (src)), BITS_PER_WORD);

  /* Copy the structure BITSIZE bits at a time.  */
  for (bitpos = 0, xbitpos = padding_correction;
       bitpos < bytes * BITS_PER_UNIT;
       bitpos += bitsize, xbitpos += bitsize)
    {
      /* We need a new destination pseudo each time xbitpos is
         on a word boundary and when xbitpos == padding_correction
         (the first time through).  */
      if (xbitpos % BITS_PER_WORD == 0
          || xbitpos == padding_correction)
        {
          /* Generate an appropriate register.  */
          dst_word = gen_reg_rtx (word_mode);
          dst_words[xbitpos / BITS_PER_WORD] = dst_word;

          /* Clear the destination before we move anything into it.  */
          emit_move_insn (dst_word, CONST0_RTX (word_mode));
        }

      /* We need a new source operand each time bitpos is on a word
         boundary.  */
      if (bitpos % BITS_PER_WORD == 0)
        src_word = operand_subword_force (x, bitpos / BITS_PER_WORD, BLKmode);

      /* Use bitpos for the source extraction (left justified) and
         xbitpos for the destination store (right justified).  */
      store_bit_field (dst_word, bitsize, xbitpos % BITS_PER_WORD,
                       0, 0, word_mode,
                       extract_bit_field (src_word, bitsize,
                                          bitpos % BITS_PER_WORD, 1,
                                          NULL_RTX, word_mode, word_mode));
    }

  if (mode == BLKmode)
    {
      /* Find the smallest integer mode large enough to hold the
         entire structure.  */
      for (mode = GET_CLASS_NARROWEST_MODE (MODE_INT);
           mode != VOIDmode;
           mode = GET_MODE_WIDER_MODE (mode))
        /* Have we found a large enough mode?  */
        if (GET_MODE_SIZE (mode) >= bytes)
          break;

      /* A suitable mode should have been found.  */
      gcc_assert (mode != VOIDmode);
    }

  if (GET_MODE_SIZE (mode) < GET_MODE_SIZE (word_mode))
    dst_mode = word_mode;
  else
    dst_mode = mode;
  dst = gen_reg_rtx (dst_mode);

  for (i = 0; i < n_regs; i++)
    emit_move_insn (operand_subword (dst, i, 0, dst_mode), dst_words[i]);

  if (mode != dst_mode)
    dst = gen_lowpart (mode, dst);

  return dst;
}

/* Add a USE expression for REG to the (possibly empty) list pointed
   to by CALL_FUSAGE.  REG must denote a hard register.  */

void
use_reg_mode (rtx *call_fusage, rtx reg, machine_mode mode)
{
  gcc_assert (REG_P (reg) && REGNO (reg) < FIRST_PSEUDO_REGISTER);

  *call_fusage
    = gen_rtx_EXPR_LIST (mode, gen_rtx_USE (VOIDmode, reg), *call_fusage);
}

/* Add a CLOBBER expression for REG to the (possibly empty) list pointed
   to by CALL_FUSAGE.  REG must denote a hard register.  */

void
clobber_reg_mode (rtx *call_fusage, rtx reg, machine_mode mode)
{
  gcc_assert (REG_P (reg) && REGNO (reg) < FIRST_PSEUDO_REGISTER);

  *call_fusage
    = gen_rtx_EXPR_LIST (mode, gen_rtx_CLOBBER (VOIDmode, reg), *call_fusage);
}

/* Add USE expressions to *CALL_FUSAGE for each of NREGS consecutive regs,
   starting at REGNO.  All of these registers must be hard registers.  */

void
use_regs (rtx *call_fusage, int regno, int nregs)
{
  int i;

  gcc_assert (regno + nregs <= FIRST_PSEUDO_REGISTER);

  for (i = 0; i < nregs; i++)
    use_reg (call_fusage, regno_reg_rtx[regno + i]);
}

/* Add USE expressions to *CALL_FUSAGE for each REG contained in the
   PARALLEL REGS.  This is for calls that pass values in multiple
   non-contiguous locations.  The Irix 6 ABI has examples of this.  */

void
use_group_regs (rtx *call_fusage, rtx regs)
{
  int i;

  for (i = 0; i < XVECLEN (regs, 0); i++)
    {
      rtx reg = XEXP (XVECEXP (regs, 0, i), 0);

      /* A NULL entry means the parameter goes both on the stack and in
         registers.  This can also be a MEM for targets that pass values
         partially on the stack and partially in registers.  */
      if (reg != 0 && REG_P (reg))
        use_reg (call_fusage, reg);
    }
}

/* Return the defining gimple statement for SSA_NAME NAME if it is an
   assigment and the code of the expresion on the RHS is CODE.  Return
   NULL otherwise.  */

static gimple
get_def_for_expr (tree name, enum tree_code code)
{
  gimple def_stmt;

  if (TREE_CODE (name) != SSA_NAME)
    return NULL;

  def_stmt = get_gimple_for_ssa_name (name);
  if (!def_stmt
      || gimple_assign_rhs_code (def_stmt) != code)
    return NULL;

  return def_stmt;
}

#ifdef HAVE_conditional_move
/* Return the defining gimple statement for SSA_NAME NAME if it is an
   assigment and the class of the expresion on the RHS is CLASS.  Return
   NULL otherwise.  */

static gimple
get_def_for_expr_class (tree name, enum tree_code_class tclass)
{
  gimple def_stmt;

  if (TREE_CODE (name) != SSA_NAME)
    return NULL;

  def_stmt = get_gimple_for_ssa_name (name);
  if (!def_stmt
      || TREE_CODE_CLASS (gimple_assign_rhs_code (def_stmt)) != tclass)
    return NULL;

  return def_stmt;
}
#endif
\f

/* Determine whether the LEN bytes generated by CONSTFUN can be
   stored to memory using several move instructions.  CONSTFUNDATA is
   a pointer which will be passed as argument in every CONSTFUN call.
   ALIGN is maximum alignment we can assume.  MEMSETP is true if this is
   a memset operation and false if it's a copy of a constant string.
   Return nonzero if a call to store_by_pieces should succeed.  */

int
can_store_by_pieces (unsigned HOST_WIDE_INT len,
                     rtx (*constfun) (void *, HOST_WIDE_INT, machine_mode),
                     void *constfundata, unsigned int align, bool memsetp)
{
  unsigned HOST_WIDE_INT l;
  unsigned int max_size;
  HOST_WIDE_INT offset = 0;
  machine_mode mode;
  enum insn_code icode;
  int reverse;
  /* cst is set but not used if LEGITIMATE_CONSTANT doesn't use it.  */
  rtx cst ATTRIBUTE_UNUSED;

  if (len == 0)
    return 1;

  if (! (memsetp
         ? SET_BY_PIECES_P (len, align)
         : STORE_BY_PIECES_P (len, align)))
    return 0;

  align = alignment_for_piecewise_move (STORE_MAX_PIECES, align);

  /* We would first store what we can in the largest integer mode, then go to
     successively smaller modes.  */

  for (reverse = 0;
       reverse <= (HAVE_PRE_DECREMENT || HAVE_POST_DECREMENT);
       reverse++)
    {
      l = len;
      max_size = STORE_MAX_PIECES + 1;
      while (max_size > 1 && l > 0)
        {
          mode = widest_int_mode_for_size (max_size);

          if (mode == VOIDmode)
            break;

          icode = optab_handler (mov_optab, mode);
          if (icode != CODE_FOR_nothing
              && align >= GET_MODE_ALIGNMENT (mode))
            {
              unsigned int size = GET_MODE_SIZE (mode);

              while (l >= size)
                {
                  if (reverse)
                    offset -= size;

                  cst = (*constfun) (constfundata, offset, mode);
                  if (!targetm.legitimate_constant_p (mode, cst))
                    return 0;

                  if (!reverse)
                    offset += size;

                  l -= size;
                }
            }

          max_size = GET_MODE_SIZE (mode);
        }

      /* The code above should have handled everything.  */
      gcc_assert (!l);
    }

  return 1;
}

/* Generate several move instructions to store LEN bytes generated by
   CONSTFUN to block TO.  (A MEM rtx with BLKmode).  CONSTFUNDATA is a
   pointer which will be passed as argument in every CONSTFUN call.
   ALIGN is maximum alignment we can assume.  MEMSETP is true if this is
   a memset operation and false if it's a copy of a constant string.
   If ENDP is 0 return to, if ENDP is 1 return memory at the end ala
   mempcpy, and if ENDP is 2 return memory the end minus one byte ala
   stpcpy.  */

rtx
store_by_pieces (rtx to, unsigned HOST_WIDE_INT len,
                 rtx (*constfun) (void *, HOST_WIDE_INT, machine_mode),
                 void *constfundata, unsigned int align, bool memsetp, int endp)
{
  machine_mode to_addr_mode = get_address_mode (to);
  struct store_by_pieces_d data;

  if (len == 0)
    {
      gcc_assert (endp != 2);
      return to;
    }

  gcc_assert (memsetp
              ? SET_BY_PIECES_P (len, align)
              : STORE_BY_PIECES_P (len, align));
  data.constfun = constfun;
  data.constfundata = constfundata;
  data.len = len;
  data.to = to;
  store_by_pieces_1 (&data, align);
  if (endp)
    {
      rtx to1;

      gcc_assert (!data.reverse);
      if (data.autinc_to)
        {
          if (endp == 2)
            {
              if (HAVE_POST_INCREMENT && data.explicit_inc_to > 0)
                emit_insn (gen_add2_insn (data.to_addr, constm1_rtx));
              else
                data.to_addr = copy_to_mode_reg (to_addr_mode,
                                                 plus_constant (to_addr_mode,
                                                                data.to_addr,
                                                                -1));
            }
          to1 = adjust_automodify_address (data.to, QImode, data.to_addr,
                                           data.offset);
        }
      else
        {
          if (endp == 2)
            --data.offset;
          to1 = adjust_address (data.to, QImode, data.offset);
        }
      return to1;
    }
  else
    return data.to;
}

/* Generate several move instructions to clear LEN bytes of block TO.  (A MEM
   rtx with BLKmode).  ALIGN is maximum alignment we can assume.  */

static void
clear_by_pieces (rtx to, unsigned HOST_WIDE_INT len, unsigned int align)
{
  struct store_by_pieces_d data;

  if (len == 0)
    return;

  data.constfun = clear_by_pieces_1;
  data.constfundata = NULL;
  data.len = len;
  data.to = to;
  store_by_pieces_1 (&data, align);
}

/* Callback routine for clear_by_pieces.
   Return const0_rtx unconditionally.  */

static rtx
clear_by_pieces_1 (void *data ATTRIBUTE_UNUSED,
                   HOST_WIDE_INT offset ATTRIBUTE_UNUSED,
                   machine_mode mode ATTRIBUTE_UNUSED)
{
  return const0_rtx;
}

/* Subroutine of clear_by_pieces and store_by_pieces.
   Generate several move instructions to store LEN bytes of block TO.  (A MEM
   rtx with BLKmode).  ALIGN is maximum alignment we can assume.  */

static void
store_by_pieces_1 (struct store_by_pieces_d *data ATTRIBUTE_UNUSED,
                   unsigned int align ATTRIBUTE_UNUSED)
{
  machine_mode to_addr_mode = get_address_mode (data->to);
  rtx to_addr = XEXP (data->to, 0);
  unsigned int max_size = STORE_MAX_PIECES + 1;
  enum insn_code icode;

  data->offset = 0;
  data->to_addr = to_addr;
  data->autinc_to
    = (GET_CODE (to_addr) == PRE_INC || GET_CODE (to_addr) == PRE_DEC
       || GET_CODE (to_addr) == POST_INC || GET_CODE (to_addr) == POST_DEC);

  data->explicit_inc_to = 0;
  data->reverse
    = (GET_CODE (to_addr) == PRE_DEC || GET_CODE (to_addr) == POST_DEC);
  if (data->reverse)
    data->offset = data->len;

  /* If storing requires more than two move insns,
     copy addresses to registers (to make displacements shorter)
     and use post-increment if available.  */
  if (!data->autinc_to
      && move_by_pieces_ninsns (data->len, align, max_size) > 2)
    {
      /* Determine the main mode we'll be using.
         MODE might not be used depending on the definitions of the
         USE_* macros below.  */
      machine_mode mode ATTRIBUTE_UNUSED
        = widest_int_mode_for_size (max_size);

      if (USE_STORE_PRE_DECREMENT (mode) && data->reverse && ! data->autinc_to)
        {
          data->to_addr = copy_to_mode_reg (to_addr_mode,
                                            plus_constant (to_addr_mode,
                                                           to_addr,
                                                           data->len));
          data->autinc_to = 1;
          data->explicit_inc_to = -1;
        }

      if (USE_STORE_POST_INCREMENT (mode) && ! data->reverse
          && ! data->autinc_to)
        {
          data->to_addr = copy_to_mode_reg (to_addr_mode, to_addr);
          data->autinc_to = 1;
          data->explicit_inc_to = 1;
        }

      if ( !data->autinc_to && CONSTANT_P (to_addr))
        data->to_addr = copy_to_mode_reg (to_addr_mode, to_addr);
    }

  align = alignment_for_piecewise_move (STORE_MAX_PIECES, align);

  /* First store what we can in the largest integer mode, then go to
     successively smaller modes.  */

  while (max_size > 1 && data->len > 0)
    {
      machine_mode mode = widest_int_mode_for_size (max_size);

      if (mode == VOIDmode)
        break;

      icode = optab_handler (mov_optab, mode);
      if (icode != CODE_FOR_nothing && align >= GET_MODE_ALIGNMENT (mode))
        store_by_pieces_2 (GEN_FCN (icode), mode, data);

      max_size = GET_MODE_SIZE (mode);
    }

  /* The code above should have handled everything.  */
  gcc_assert (!data->len);
}

/* Subroutine of store_by_pieces_1.  Store as many bytes as appropriate
   with move instructions for mode MODE.  GENFUN is the gen_... function
   to make a move insn for that mode.  DATA has all the other info.  */

static void
store_by_pieces_2 (insn_gen_fn genfun, machine_mode mode,
                   struct store_by_pieces_d *data)
{
  unsigned int size = GET_MODE_SIZE (mode);
  rtx to1, cst;

  while (data->len >= size)
    {
      if (data->reverse)
        data->offset -= size;

      if (data->autinc_to)
        to1 = adjust_automodify_address (data->to, mode, data->to_addr,
                                         data->offset);
      else
        to1 = adjust_address (data->to, mode, data->offset);

      if (HAVE_PRE_DECREMENT && data->explicit_inc_to < 0)
        emit_insn (gen_add2_insn (data->to_addr,
                                  gen_int_mode (-(HOST_WIDE_INT) size,
                                                GET_MODE (data->to_addr))));

      cst = (*data->constfun) (data->constfundata, data->offset, mode);
      emit_insn ((*genfun) (to1, cst));

      if (HAVE_POST_INCREMENT && data->explicit_inc_to > 0)
        emit_insn (gen_add2_insn (data->to_addr,
                                  gen_int_mode (size,
                                                GET_MODE (data->to_addr))));

      if (! data->reverse)
        data->offset += size;

      data->len -= size;
    }
}
\f
/* Write zeros through the storage of OBJECT.  If OBJECT has BLKmode, SIZE is
   its length in bytes.  */

rtx
clear_storage_hints (rtx object, rtx size, enum block_op_methods method,
                     unsigned int expected_align, HOST_WIDE_INT expected_size,
                     unsigned HOST_WIDE_INT min_size,
                     unsigned HOST_WIDE_INT max_size,
                     unsigned HOST_WIDE_INT probable_max_size)
{
  machine_mode mode = GET_MODE (object);
  unsigned int align;

  gcc_assert (method == BLOCK_OP_NORMAL || method == BLOCK_OP_TAILCALL);

  /* If OBJECT is not BLKmode and SIZE is the same size as its mode,
     just move a zero.  Otherwise, do this a piece at a time.  */
  if (mode != BLKmode
      && CONST_INT_P (size)
      && INTVAL (size) == (HOST_WIDE_INT) GET_MODE_SIZE (mode))
    {
      rtx zero = CONST0_RTX (mode);
      if (zero != NULL)
        {
          emit_move_insn (object, zero);
          return NULL;
        }

      if (COMPLEX_MODE_P (mode))
        {
          zero = CONST0_RTX (GET_MODE_INNER (mode));
          if (zero != NULL)
            {
              write_complex_part (object, zero, 0);
              write_complex_part (object, zero, 1);
              return NULL;
            }
        }
    }

  if (size == const0_rtx)
    return NULL;

  align = MEM_ALIGN (object);

  if (CONST_INT_P (size)
      && CLEAR_BY_PIECES_P (INTVAL (size), align))
    clear_by_pieces (object, INTVAL (size), align);
  else if (set_storage_via_setmem (object, size, const0_rtx, align,
                                   expected_align, expected_size,
                                   min_size, max_size, probable_max_size))
    ;
  else if (ADDR_SPACE_GENERIC_P (MEM_ADDR_SPACE (object)))
    return set_storage_via_libcall (object, size, const0_rtx,
                                    method == BLOCK_OP_TAILCALL);
  else
    gcc_unreachable ();

  return NULL;
}

rtx
clear_storage (rtx object, rtx size, enum block_op_methods method)
{
  unsigned HOST_WIDE_INT max, min = 0;
  if (GET_CODE (size) == CONST_INT)
    min = max = UINTVAL (size);
  else
    max = GET_MODE_MASK (GET_MODE (size));
  return clear_storage_hints (object, size, method, 0, -1, min, max, max);
}


/* A subroutine of clear_storage.  Expand a call to memset.
   Return the return value of memset, 0 otherwise.  */

rtx
set_storage_via_libcall (rtx object, rtx size, rtx val, bool tailcall)
{
  tree call_expr, fn, object_tree, size_tree, val_tree;
  machine_mode size_mode;
  rtx retval;

  /* Emit code to copy OBJECT and SIZE into new pseudos.  We can then
     place those into new pseudos into a VAR_DECL and use them later.  */

  object = copy_addr_to_reg (XEXP (object, 0));

  size_mode = TYPE_MODE (sizetype);
  size = convert_to_mode (size_mode, size, 1);
  size = copy_to_mode_reg (size_mode, size);

  /* It is incorrect to use the libcall calling conventions to call
     memset in this context.  This could be a user call to memset and
     the user may wish to examine the return value from memset.  For
     targets where libcalls and normal calls have different conventions
     for returning pointers, we could end up generating incorrect code.  */

  object_tree = make_tree (ptr_type_node, object);
  if (!CONST_INT_P (val))
    val = convert_to_mode (TYPE_MODE (integer_type_node), val, 1);
  size_tree = make_tree (sizetype, size);
  val_tree = make_tree (integer_type_node, val);

  fn = clear_storage_libcall_fn (true);
  call_expr = build_call_expr (fn, 3, object_tree, val_tree, size_tree);
  CALL_EXPR_TAILCALL (call_expr) = tailcall;

  retval = expand_normal (call_expr);

  return retval;
}

/* A subroutine of set_storage_via_libcall.  Create the tree node
   for the function we use for block clears.  */

tree block_clear_fn;

void
init_block_clear_fn (const char *asmspec)
{
  if (!block_clear_fn)
    {
      tree fn, args;

      fn = get_identifier ("memset");
      args = build_function_type_list (ptr_type_node, ptr_type_node,
                                       integer_type_node, sizetype,
                                       NULL_TREE);

      fn = build_decl (UNKNOWN_LOCATION, FUNCTION_DECL, fn, args);
      DECL_EXTERNAL (fn) = 1;
      TREE_PUBLIC (fn) = 1;
      DECL_ARTIFICIAL (fn) = 1;
      TREE_NOTHROW (fn) = 1;
      DECL_VISIBILITY (fn) = VISIBILITY_DEFAULT;
      DECL_VISIBILITY_SPECIFIED (fn) = 1;

      block_clear_fn = fn;
    }

  if (asmspec)
    set_user_assembler_name (block_clear_fn, asmspec);
}

static tree
clear_storage_libcall_fn (int for_call)
{
  static bool emitted_extern;

  if (!block_clear_fn)
    init_block_clear_fn (NULL);

  if (for_call && !emitted_extern)
    {
      emitted_extern = true;
      make_decl_rtl (block_clear_fn);
    }

  return block_clear_fn;
}
\f
/* Expand a setmem pattern; return true if successful.  */

bool
set_storage_via_setmem (rtx object, rtx size, rtx val, unsigned int align,
                        unsigned int expected_align, HOST_WIDE_INT expected_size,
                        unsigned HOST_WIDE_INT min_size,
                        unsigned HOST_WIDE_INT max_size,
                        unsigned HOST_WIDE_INT probable_max_size)
{
  /* Try the most limited insn first, because there's no point
     including more than one in the machine description unless
     the more limited one has some advantage.  */

  machine_mode mode;

  if (expected_align < align)
    expected_align = align;
  if (expected_size != -1)
    {
      if ((unsigned HOST_WIDE_INT)expected_size > max_size)
        expected_size = max_size;
      if ((unsigned HOST_WIDE_INT)expected_size < min_size)
        expected_size = min_size;
    }

  for (mode = GET_CLASS_NARROWEST_MODE (MODE_INT); mode != VOIDmode;
       mode = GET_MODE_WIDER_MODE (mode))
    {
      enum insn_code code = direct_optab_handler (setmem_optab, mode);

      if (code != CODE_FOR_nothing
          /* We don't need MODE to be narrower than BITS_PER_HOST_WIDE_INT
             here because if SIZE is less than the mode mask, as it is
             returned by the macro, it will definitely be less than the
             actual mode mask.  Since SIZE is within the Pmode address
             space, we limit MODE to Pmode.  */
          && ((CONST_INT_P (size)
               && ((unsigned HOST_WIDE_INT) INTVAL (size)
                   <= (GET_MODE_MASK (mode) >> 1)))
              || max_size <= (GET_MODE_MASK (mode) >> 1)
              || GET_MODE_BITSIZE (mode) >= GET_MODE_BITSIZE (Pmode)))
        {
          struct expand_operand ops[9];
          unsigned int nops;

          nops = insn_data[(int) code].n_generator_args;
          gcc_assert (nops == 4 || nops == 6 || nops == 8 || nops == 9);

          create_fixed_operand (&ops[0], object);
          /* The check above guarantees that this size conversion is valid.  */
          create_convert_operand_to (&ops[1], size, mode, true);
          create_convert_operand_from (&ops[2], val, byte_mode, true);
          create_integer_operand (&ops[3], align / BITS_PER_UNIT);
          if (nops >= 6)
            {
              create_integer_operand (&ops[4], expected_align / BITS_PER_UNIT);
              create_integer_operand (&ops[5], expected_size);
            }
          if (nops >= 8)
            {
              create_integer_operand (&ops[6], min_size);
              /* If we can not represent the maximal size,
                 make parameter NULL.  */
              if ((HOST_WIDE_INT) max_size != -1)
                create_integer_operand (&ops[7], max_size);
              else
                create_fixed_operand (&ops[7], NULL);
            }
          if (nops == 9)
            {
              /* If we can not represent the maximal size,
                 make parameter NULL.  */
              if ((HOST_WIDE_INT) probable_max_size != -1)
                create_integer_operand (&ops[8], probable_max_size);
              else
                create_fixed_operand (&ops[8], NULL);
            }
          if (maybe_expand_insn (code, nops, ops))
            return true;
        }
    }

  return false;
}

\f
/* Write to one of the components of the complex value CPLX.  Write VAL to
   the real part if IMAG_P is false, and the imaginary part if its true.  */

static void
write_complex_part (rtx cplx, rtx val, bool imag_p)
{
  machine_mode cmode;
  machine_mode imode;
  unsigned ibitsize;

  if (GET_CODE (cplx) == CONCAT)
    {
      emit_move_insn (XEXP (cplx, imag_p), val);
      return;
    }

  cmode = GET_MODE (cplx);
  imode = GET_MODE_INNER (cmode);
  ibitsize = GET_MODE_BITSIZE (imode);

  /* For MEMs simplify_gen_subreg may generate an invalid new address
     because, e.g., the original address is considered mode-dependent
     by the target, which restricts simplify_subreg from invoking
     adjust_address_nv.  Instead of preparing fallback support for an
     invalid address, we call adjust_address_nv directly.  */
  if (MEM_P (cplx))
    {
      emit_move_insn (adjust_address_nv (cplx, imode,
                                         imag_p ? GET_MODE_SIZE (imode) : 0),
                      val);
      return;
    }

  /* If the sub-object is at least word sized, then we know that subregging
     will work.  This special case is important, since store_bit_field
     wants to operate on integer modes, and there's rarely an OImode to
     correspond to TCmode.  */
  if (ibitsize >= BITS_PER_WORD
      /* For hard regs we have exact predicates.  Assume we can split
         the original object if it spans an even number of hard regs.
         This special case is important for SCmode on 64-bit platforms
         where the natural size of floating-point regs is 32-bit.  */
      || (REG_P (cplx)
          && REGNO (cplx) < FIRST_PSEUDO_REGISTER
          && hard_regno_nregs[REGNO (cplx)][cmode] % 2 == 0))
    {
      rtx part = simplify_gen_subreg (imode, cplx, cmode,
                                      imag_p ? GET_MODE_SIZE (imode) : 0);
      if (part)
        {
          emit_move_insn (part, val);
          return;
        }
      else
        /* simplify_gen_subreg may fail for sub-word MEMs.  */
        gcc_assert (MEM_P (cplx) && ibitsize < BITS_PER_WORD);
    }

  store_bit_field (cplx, ibitsize, imag_p ? ibitsize : 0, 0, 0, imode, val);
}

/* Extract one of the components of the complex value CPLX.  Extract the
   real part if IMAG_P is false, and the imaginary part if it's true.  */

static rtx
read_complex_part (rtx cplx, bool imag_p)
{
  machine_mode cmode, imode;
  unsigned ibitsize;

  if (GET_CODE (cplx) == CONCAT)
    return XEXP (cplx, imag_p);

  cmode = GET_MODE (cplx);
  imode = GET_MODE_INNER (cmode);
  ibitsize = GET_MODE_BITSIZE (imode);

  /* Special case reads from complex constants that got spilled to memory.  */
  if (MEM_P (cplx) && GET_CODE (XEXP (cplx, 0)) == SYMBOL_REF)
    {
      tree decl = SYMBOL_REF_DECL (XEXP (cplx, 0));
      if (decl && TREE_CODE (decl) == COMPLEX_CST)
        {
          tree part = imag_p ? TREE_IMAGPART (decl) : TREE_REALPART (decl);
          if (CONSTANT_CLASS_P (part))
            return expand_expr (part, NULL_RTX, imode, EXPAND_NORMAL);
        }
    }

  /* For MEMs simplify_gen_subreg may generate an invalid new address
     because, e.g., the original address is considered mode-dependent
     by the target, which restricts simplify_subreg from invoking
     adjust_address_nv.  Instead of preparing fallback support for an
     invalid address, we call adjust_address_nv directly.  */
  if (MEM_P (cplx))
    return adjust_address_nv (cplx, imode,
                              imag_p ? GET_MODE_SIZE (imode) : 0);

  /* If the sub-object is at least word sized, then we know that subregging
     will work.  This special case is important, since extract_bit_field
     wants to operate on integer modes, and there's rarely an OImode to
     correspond to TCmode.  */
  if (ibitsize >= BITS_PER_WORD
      /* For hard regs we have exact predicates.  Assume we can split
         the original object if it spans an even number of hard regs.
         This special case is important for SCmode on 64-bit platforms
         where the natural size of floating-point regs is 32-bit.  */
      || (REG_P (cplx)
          && REGNO (cplx) < FIRST_PSEUDO_REGISTER
          && hard_regno_nregs[REGNO (cplx)][cmode] % 2 == 0))
    {
      rtx ret = simplify_gen_subreg (imode, cplx, cmode,
                                     imag_p ? GET_MODE_SIZE (imode) : 0);
      if (ret)
        return ret;
      else
        /* simplify_gen_subreg may fail for sub-word MEMs.  */
        gcc_assert (MEM_P (cplx) && ibitsize < BITS_PER_WORD);
    }

  return extract_bit_field (cplx, ibitsize, imag_p ? ibitsize : 0,
                            true, NULL_RTX, imode, imode);
}
\f
/* A subroutine of emit_move_insn_1.  Yet another lowpart generator.
   NEW_MODE and OLD_MODE are the same size.  Return NULL if X cannot be
   represented in NEW_MODE.  If FORCE is true, this will never happen, as
   we'll force-create a SUBREG if needed.  */

static rtx
emit_move_change_mode (machine_mode new_mode,
                       machine_mode old_mode, rtx x, bool force)
{
  rtx ret;

  if (push_operand (x, GET_MODE (x)))
    {
      ret = gen_rtx_MEM (new_mode, XEXP (x, 0));
      MEM_COPY_ATTRIBUTES (ret, x);
    }
  else if (MEM_P (x))
    {
      /* We don't have to worry about changing the address since the
         size in bytes is supposed to be the same.  */
      if (reload_in_progress)
        {
          /* Copy the MEM to change the mode and move any
             substitutions from the old MEM to the new one.  */
          ret = adjust_address_nv (x, new_mode, 0);
          copy_replacements (x, ret);
        }
      else
        ret = adjust_address (x, new_mode, 0);
    }
  else
    {
      /* Note that we do want simplify_subreg's behavior of validating
         that the new mode is ok for a hard register.  If we were to use
         simplify_gen_subreg, we would create the subreg, but would
         probably run into the target not being able to implement it.  */
      /* Except, of course, when FORCE is true, when this is exactly what
         we want.  Which is needed for CCmodes on some targets.  */
      if (force)
        ret = simplify_gen_subreg (new_mode, x, old_mode, 0);
      else
        ret = simplify_subreg (new_mode, x, old_mode, 0);
    }

  return ret;
}

/* A subroutine of emit_move_insn_1.  Generate a move from Y into X using
   an integer mode of the same size as MODE.  Returns the instruction
   emitted, or NULL if such a move could not be generated.  */

static rtx_insn *
emit_move_via_integer (machine_mode mode, rtx x, rtx y, bool force)
{
  machine_mode imode;
  enum insn_code code;

  /* There must exist a mode of the exact size we require.  */
  imode = int_mode_for_mode (mode);
  if (imode == BLKmode)
    return NULL;

  /* The target must support moves in this mode.  */
  code = optab_handler (mov_optab, imode);
  if (code == CODE_FOR_nothing)
    return NULL;

  x = emit_move_change_mode (imode, mode, x, force);
  if (x == NULL_RTX)
    return NULL;
  y = emit_move_change_mode (imode, mode, y, force);
  if (y == NULL_RTX)
    return NULL;
  return emit_insn (GEN_FCN (code) (x, y));
}

/* A subroutine of emit_move_insn_1.  X is a push_operand in MODE.
   Return an equivalent MEM that does not use an auto-increment.  */

rtx
emit_move_resolve_push (machine_mode mode, rtx x)
{
  enum rtx_code code = GET_CODE (XEXP (x, 0));
  HOST_WIDE_INT adjust;
  rtx temp;

  adjust = GET_MODE_SIZE (mode);
#ifdef PUSH_ROUNDING
  adjust = PUSH_ROUNDING (adjust);
#endif
  if (code == PRE_DEC || code == POST_DEC)
    adjust = -adjust;
  else if (code == PRE_MODIFY || code == POST_MODIFY)
    {
      rtx expr = XEXP (XEXP (x, 0), 1);
      HOST_WIDE_INT val;

      gcc_assert (GET_CODE (expr) == PLUS || GET_CODE (expr) == MINUS);
      gcc_assert (CONST_INT_P (XEXP (expr, 1)));
      val = INTVAL (XEXP (expr, 1));
      if (GET_CODE (expr) == MINUS)
        val = -val;
      gcc_assert (adjust == val || adjust == -val);
      adjust = val;
    }

  /* Do not use anti_adjust_stack, since we don't want to update
     stack_pointer_delta.  */
  temp = expand_simple_binop (Pmode, PLUS, stack_pointer_rtx,
                              gen_int_mode (adjust, Pmode), stack_pointer_rtx,
                              0, OPTAB_LIB_WIDEN);
  if (temp != stack_pointer_rtx)
    emit_move_insn (stack_pointer_rtx, temp);

  switch (code)
    {
    case PRE_INC:
    case PRE_DEC:
    case PRE_MODIFY:
      temp = stack_pointer_rtx;
      break;
    case POST_INC:
    case POST_DEC:
    case POST_MODIFY:
      temp = plus_constant (Pmode, stack_pointer_rtx, -adjust);
      break;
    default:
      gcc_unreachable ();
    }

  return replace_equiv_address (x, temp);
}

/* A subroutine of emit_move_complex.  Generate a move from Y into X.
   X is known to satisfy push_operand, and MODE is known to be complex.
   Returns the last instruction emitted.  */

rtx_insn *
emit_move_complex_push (machine_mode mode, rtx x, rtx y)
{
  machine_mode submode = GET_MODE_INNER (mode);
  bool imag_first;

#ifdef PUSH_ROUNDING
  unsigned int submodesize = GET_MODE_SIZE (submode);

  /* In case we output to the stack, but the size is smaller than the
     machine can push exactly, we need to use move instructions.  */
  if (PUSH_ROUNDING (submodesize) != submodesize)
    {
      x = emit_move_resolve_push (mode, x);
      return emit_move_insn (x, y);
    }
#endif

  /* Note that the real part always precedes the imag part in memory
     regardless of machine's endianness.  */
  switch (GET_CODE (XEXP (x, 0)))
    {
    case PRE_DEC:
    case POST_DEC:
      imag_first = true;
      break;
    case PRE_INC:
    case POST_INC:
      imag_first = false;
      break;
    default:
      gcc_unreachable ();
    }

  emit_move_insn (gen_rtx_MEM (submode, XEXP (x, 0)),
                  read_complex_part (y, imag_first));
  return emit_move_insn (gen_rtx_MEM (submode, XEXP (x, 0)),
                         read_complex_part (y, !imag_first));
}

/* A subroutine of emit_move_complex.  Perform the move from Y to X
   via two moves of the parts.  Returns the last instruction emitted.  */

rtx_insn *
emit_move_complex_parts (rtx x, rtx y)
{
  /* Show the output dies here.  This is necessary for SUBREGs
     of pseudos since we cannot track their lifetimes correctly;
     hard regs shouldn't appear here except as return values.  */
  if (!reload_completed && !reload_in_progress
      && REG_P (x) && !reg_overlap_mentioned_p (x, y))
    emit_clobber (x);

  write_complex_part (x, read_complex_part (y, false), false);
  write_complex_part (x, read_complex_part (y, true), true);

  return get_last_insn ();
}

/* A subroutine of emit_move_insn_1.  Generate a move from Y into X.
   MODE is known to be complex.  Returns the last instruction emitted.  */

static rtx_insn *
emit_move_complex (machine_mode mode, rtx x, rtx y)
{
  bool try_int;

  /* Need to take special care for pushes, to maintain proper ordering
     of the data, and possibly extra padding.  */
  if (push_operand (x, mode))
    return emit_move_complex_push (mode, x, y);

  /* See if we can coerce the target into moving both values at once, except
     for floating point where we favor moving as parts if this is easy.  */
  if (GET_MODE_CLASS (mode) == MODE_COMPLEX_FLOAT
      && optab_handler (mov_optab, GET_MODE_INNER (mode)) != CODE_FOR_nothing
      && !(REG_P (x)
           && HARD_REGISTER_P (x)
           && hard_regno_nregs[REGNO (x)][mode] == 1)
      && !(REG_P (y)
           && HARD_REGISTER_P (y)
           && hard_regno_nregs[REGNO (y)][mode] == 1))
    try_int = false;
  /* Not possible if the values are inherently not adjacent.  */
  else if (GET_CODE (x) == CONCAT || GET_CODE (y) == CONCAT)
    try_int = false;
  /* Is possible if both are registers (or subregs of registers).  */
  else if (register_operand (x, mode) && register_operand (y, mode))
    try_int = true;
  /* If one of the operands is a memory, and alignment constraints
     are friendly enough, we may be able to do combined memory operations.
     We do not attempt this if Y is a constant because that combination is
     usually better with the by-parts thing below.  */
  else if ((MEM_P (x) ? !CONSTANT_P (y) : MEM_P (y))
           && (!STRICT_ALIGNMENT
               || get_mode_alignment (mode) == BIGGEST_ALIGNMENT))
    try_int = true;
  else
    try_int = false;

  if (try_int)
    {
      rtx_insn *ret;

      /* For memory to memory moves, optimal behavior can be had with the
         existing block move logic.  */
      if (MEM_P (x) && MEM_P (y))
        {
          emit_block_move (x, y, GEN_INT (GET_MODE_SIZE (mode)),
                           BLOCK_OP_NO_LIBCALL);
          return get_last_insn ();
        }

      ret = emit_move_via_integer (mode, x, y, true);
      if (ret)
        return ret;
    }

  return emit_move_complex_parts (x, y);
}

/* A subroutine of emit_move_insn_1.  Generate a move from Y into X.
   MODE is known to be MODE_CC.  Returns the last instruction emitted.  */

static rtx_insn *
emit_move_ccmode (machine_mode mode, rtx x, rtx y)
{
  rtx_insn *ret;

  /* Assume all MODE_CC modes are equivalent; if we have movcc, use it.  */
  if (mode != CCmode)
    {
      enum insn_code code = optab_handler (mov_optab, CCmode);
      if (code != CODE_FOR_nothing)
        {
          x = emit_move_change_mode (CCmode, mode, x, true);
          y = emit_move_change_mode (CCmode, mode, y, true);
          return emit_insn (GEN_FCN (code) (x, y));
        }
    }

  /* Otherwise, find the MODE_INT mode of the same width.  */
  ret = emit_move_via_integer (mode, x, y, false);
  gcc_assert (ret != NULL);
  return ret;
}

/* Return true if word I of OP lies entirely in the
   undefined bits of a paradoxical subreg.  */

static bool
undefined_operand_subword_p (const_rtx op, int i)
{
  machine_mode innermode, innermostmode;
  int offset;
  if (GET_CODE (op) != SUBREG)
    return false;
  innermode = GET_MODE (op);
  innermostmode = GET_MODE (SUBREG_REG (op));
  offset = i * UNITS_PER_WORD + SUBREG_BYTE (op);
  /* The SUBREG_BYTE represents offset, as if the value were stored in
     memory, except for a paradoxical subreg where we define
     SUBREG_BYTE to be 0; undo this exception as in
     simplify_subreg.  */
  if (SUBREG_BYTE (op) == 0
      && GET_MODE_SIZE (innermostmode) < GET_MODE_SIZE (innermode))
    {
      int difference = (GET_MODE_SIZE (innermostmode) - GET_MODE_SIZE (innermode));
      if (WORDS_BIG_ENDIAN)
        offset += (difference / UNITS_PER_WORD) * UNITS_PER_WORD;
      if (BYTES_BIG_ENDIAN)
        offset += difference % UNITS_PER_WORD;
    }
  if (offset >= GET_MODE_SIZE (innermostmode)
      || offset <= -GET_MODE_SIZE (word_mode))
    return true;
  return false;
}

/* A subroutine of emit_move_insn_1.  Generate a move from Y into X.
   MODE is any multi-word or full-word mode that lacks a move_insn
   pattern.  Note that you will get better code if you define such
   patterns, even if they must turn into multiple assembler instructions.  */

static rtx_insn *
emit_move_multi_word (machine_mode mode, rtx x, rtx y)
{
  rtx_insn *last_insn = 0;
  rtx_insn *seq;
  rtx inner;
  bool need_clobber;
  int i;

  gcc_assert (GET_MODE_SIZE (mode) >= UNITS_PER_WORD);

  /* If X is a push on the stack, do the push now and replace
     X with a reference to the stack pointer.  */
  if (push_operand (x, mode))
    x = emit_move_resolve_push (mode, x);

  /* If we are in reload, see if either operand is a MEM whose address
     is scheduled for replacement.  */
  if (reload_in_progress && MEM_P (x)
      && (inner = find_replacement (&XEXP (x, 0))) != XEXP (x, 0))
    x = replace_equiv_address_nv (x, inner);
  if (reload_in_progress && MEM_P (y)
      && (inner = find_replacement (&XEXP (y, 0))) != XEXP (y, 0))
    y = replace_equiv_address_nv (y, inner);

  start_sequence ();

  need_clobber = false;
  for (i = 0;
       i < (GET_MODE_SIZE (mode) + (UNITS_PER_WORD - 1)) / UNITS_PER_WORD;
       i++)
    {
      rtx xpart = operand_subword (x, i, 1, mode);
      rtx ypart;

      /* Do not generate code for a move if it would come entirely
         from the undefined bits of a paradoxical subreg.  */
      if (undefined_operand_subword_p (y, i))
        continue;

      ypart = operand_subword (y, i, 1, mode);

      /* If we can't get a part of Y, put Y into memory if it is a
         constant.  Otherwise, force it into a register.  Then we must
         be able to get a part of Y.  */
      if (ypart == 0 && CONSTANT_P (y))
        {
          y = use_anchored_address (force_const_mem (mode, y));
          ypart = operand_subword (y, i, 1, mode);
        }
      else if (ypart == 0)
        ypart = operand_subword_force (y, i, mode);

      gcc_assert (xpart && ypart);

      need_clobber |= (GET_CODE (xpart) == SUBREG);

      last_insn = emit_move_insn (xpart, ypart);
    }

  seq = get_insns ();
  end_sequence ();

  /* Show the output dies here.  This is necessary for SUBREGs
     of pseudos since we cannot track their lifetimes correctly;
     hard regs shouldn't appear here except as return values.
     We never want to emit such a clobber after reload.  */
  if (x != y
      && ! (reload_in_progress || reload_completed)
      && need_clobber != 0)
    emit_clobber (x);

  emit_insn (seq);

  return last_insn;
}

/* Low level part of emit_move_insn.
   Called just like emit_move_insn, but assumes X and Y
   are basically valid.  */

rtx_insn *
emit_move_insn_1 (rtx x, rtx y)
{
  machine_mode mode = GET_MODE (x);
  enum insn_code code;

  gcc_assert ((unsigned int) mode < (unsigned int) MAX_MACHINE_MODE);

  code = optab_handler (mov_optab, mode);
  if (code != CODE_FOR_nothing)
    return emit_insn (GEN_FCN (code) (x, y));

  /* Expand complex moves by moving real part and imag part.  */
  if (COMPLEX_MODE_P (mode))
    return emit_move_complex (mode, x, y);

  if (GET_MODE_CLASS (mode) == MODE_DECIMAL_FLOAT
      || ALL_FIXED_POINT_MODE_P (mode))
    {
      rtx_insn *result = emit_move_via_integer (mode, x, y, true);

      /* If we can't find an integer mode, use multi words.  */
      if (result)
        return result;
      else
        return emit_move_multi_word (mode, x, y);
    }

  if (GET_MODE_CLASS (mode) == MODE_CC)
    return emit_move_ccmode (mode, x, y);

  /* Try using a move pattern for the corresponding integer mode.  This is
     only safe when simplify_subreg can convert MODE constants into integer
     constants.  At present, it can only do this reliably if the value
     fits within a HOST_WIDE_INT.  */
  if (!CONSTANT_P (y) || GET_MODE_BITSIZE (mode) <= HOST_BITS_PER_WIDE_INT)
    {
      rtx_insn *ret = emit_move_via_integer (mode, x, y, lra_in_progress);

      if (ret)
        {
          if (! lra_in_progress || recog (PATTERN (ret), ret, 0) >= 0)
            return ret;
        }
    }

  return emit_move_multi_word (mode, x, y);
}

/* Generate code to copy Y into X.
   Both Y and X must have the same mode, except that
   Y can be a constant with VOIDmode.
   This mode cannot be BLKmode; use emit_block_move for that.

   Return the last instruction emitted.  */

rtx_insn *
emit_move_insn (rtx x, rtx y)
{
  machine_mode mode = GET_MODE (x);
  rtx y_cst = NULL_RTX;
  rtx_insn *last_insn;
  rtx set;

  gcc_assert (mode != BLKmode
              && (GET_MODE (y) == mode || GET_MODE (y) == VOIDmode));

  if (CONSTANT_P (y))
    {
      if (optimize
          && SCALAR_FLOAT_MODE_P (GET_MODE (x))
          && (last_insn = compress_float_constant (x, y)))
        return last_insn;

      y_cst = y;

      if (!targetm.legitimate_constant_p (mode, y))
        {
          y = force_const_mem (mode, y);

          /* If the target's cannot_force_const_mem prevented the spill,
             assume that the target's move expanders will also take care
             of the non-legitimate constant.  */
          if (!y)
            y = y_cst;
          else
            y = use_anchored_address (y);
        }
    }

  /* If X or Y are memory references, verify that their addresses are valid
     for the machine.  */
  if (MEM_P (x)
      && (! memory_address_addr_space_p (GET_MODE (x), XEXP (x, 0),
                                         MEM_ADDR_SPACE (x))
          && ! push_operand (x, GET_MODE (x))))
    x = validize_mem (x);

  if (MEM_P (y)
      && ! memory_address_addr_space_p (GET_MODE (y), XEXP (y, 0),
                                        MEM_ADDR_SPACE (y)))
    y = validize_mem (y);

  gcc_assert (mode != BLKmode);

  last_insn = emit_move_insn_1 (x, y);

  if (y_cst && REG_P (x)
      && (set = single_set (last_insn)) != NULL_RTX
      && SET_DEST (set) == x
      && ! rtx_equal_p (y_cst, SET_SRC (set)))
    set_unique_reg_note (last_insn, REG_EQUAL, copy_rtx (y_cst));

  return last_insn;
}

/* If Y is representable exactly in a narrower mode, and the target can
   perform the extension directly from constant or memory, then emit the
   move as an extension.  */

static rtx_insn *
compress_float_constant (rtx x, rtx y)
{
  machine_mode dstmode = GET_MODE (x);
  machine_mode orig_srcmode = GET_MODE (y);
  machine_mode srcmode;
  REAL_VALUE_TYPE r;
  int oldcost, newcost;
  bool speed = optimize_insn_for_speed_p ();

  REAL_VALUE_FROM_CONST_DOUBLE (r, y);

  if (targetm.legitimate_constant_p (dstmode, y))
    oldcost = set_src_cost (y, speed);
  else
    oldcost = set_src_cost (force_const_mem (dstmode, y), speed);

  for (srcmode = GET_CLASS_NARROWEST_MODE (GET_MODE_CLASS (orig_srcmode));
       srcmode != orig_srcmode;
       srcmode = GET_MODE_WIDER_MODE (srcmode))
    {
      enum insn_code ic;
      rtx trunc_y;
      rtx_insn *last_insn;

      /* Skip if the target can't extend this way.  */
      ic = can_extend_p (dstmode, srcmode, 0);
      if (ic == CODE_FOR_nothing)
        continue;

      /* Skip if the narrowed value isn't exact.  */
      if (! exact_real_truncate (srcmode, &r))
        continue;

      trunc_y = CONST_DOUBLE_FROM_REAL_VALUE (r, srcmode);

      if (targetm.legitimate_constant_p (srcmode, trunc_y))
        {
          /* Skip if the target needs extra instructions to perform
             the extension.  */
          if (!insn_operand_matches (ic, 1, trunc_y))
            continue;
          /* This is valid, but may not be cheaper than the original. */
          newcost = set_src_cost (gen_rtx_FLOAT_EXTEND (dstmode, trunc_y),
                                  speed);
          if (oldcost < newcost)
            continue;
        }
      else if (float_extend_from_mem[dstmode][srcmode])
        {
          trunc_y = force_const_mem (srcmode, trunc_y);
          /* This is valid, but may not be cheaper than the original. */
          newcost = set_src_cost (gen_rtx_FLOAT_EXTEND (dstmode, trunc_y),
                                  speed);
          if (oldcost < newcost)
            continue;
          trunc_y = validize_mem (trunc_y);
        }
      else
        continue;

      /* For CSE's benefit, force the compressed constant pool entry
         into a new pseudo.  This constant may be used in different modes,
         and if not, combine will put things back together for us.  */
      trunc_y = force_reg (srcmode, trunc_y);

      /* If x is a hard register, perform the extension into a pseudo,
         so that e.g. stack realignment code is aware of it.  */
      rtx target = x;
      if (REG_P (x) && HARD_REGISTER_P (x))
        target = gen_reg_rtx (dstmode);

      emit_unop_insn (ic, target, trunc_y, UNKNOWN);
      last_insn = get_last_insn ();

      if (REG_P (target))
        set_unique_reg_note (last_insn, REG_EQUAL, y);

      if (target != x)
        return emit_move_insn (x, target);
      return last_insn;
    }

  return NULL;
}
\f
/* Pushing data onto the stack.  */

/* Push a block of length SIZE (perhaps variable)
   and return an rtx to address the beginning of the block.
   The value may be virtual_outgoing_args_rtx.

   EXTRA is the number of bytes of padding to push in addition to SIZE.
   BELOW nonzero means this padding comes at low addresses;
   otherwise, the padding comes at high addresses.  */

rtx
push_block (rtx size, int extra, int below)
{
  rtx temp;

  size = convert_modes (Pmode, ptr_mode, size, 1);
  if (CONSTANT_P (size))
    anti_adjust_stack (plus_constant (Pmode, size, extra));
  else if (REG_P (size) && extra == 0)
    anti_adjust_stack (size);
  else
    {
      temp = copy_to_mode_reg (Pmode, size);
      if (extra != 0)
        temp = expand_binop (Pmode, add_optab, temp,
                             gen_int_mode (extra, Pmode),
                             temp, 0, OPTAB_LIB_WIDEN);
      anti_adjust_stack (temp);
    }

#ifndef STACK_GROWS_DOWNWARD
  if (0)
#else
  if (1)
#endif
    {
      temp = virtual_outgoing_args_rtx;
      if (extra != 0 && below)
        temp = plus_constant (Pmode, temp, extra);
    }
  else
    {
      if (CONST_INT_P (size))
        temp = plus_constant (Pmode, virtual_outgoing_args_rtx,
                              -INTVAL (size) - (below ? 0 : extra));
      else if (extra != 0 && !below)
        temp = gen_rtx_PLUS (Pmode, virtual_outgoing_args_rtx,
                             negate_rtx (Pmode, plus_constant (Pmode, size,
                                                               extra)));
      else
        temp = gen_rtx_PLUS (Pmode, virtual_outgoing_args_rtx,
                             negate_rtx (Pmode, size));
    }

  return memory_address (GET_CLASS_NARROWEST_MODE (MODE_INT), temp);
}

/* A utility routine that returns the base of an auto-inc memory, or NULL.  */

static rtx
mem_autoinc_base (rtx mem)
{
  if (MEM_P (mem))
    {
      rtx addr = XEXP (mem, 0);
      if (GET_RTX_CLASS (GET_CODE (addr)) == RTX_AUTOINC)
        return XEXP (addr, 0);
    }
  return NULL;
}

/* A utility routine used here, in reload, and in try_split.  The insns
   after PREV up to and including LAST are known to adjust the stack,
   with a final value of END_ARGS_SIZE.  Iterate backward from LAST
   placing notes as appropriate.  PREV may be NULL, indicating the
   entire insn sequence prior to LAST should be scanned.

   The set of allowed stack pointer modifications is small:
     (1) One or more auto-inc style memory references (aka pushes),
     (2) One or more addition/subtraction with the SP as destination,
     (3) A single move insn with the SP as destination,
     (4) A call_pop insn,
     (5) Noreturn call insns if !ACCUMULATE_OUTGOING_ARGS.

   Insns in the sequence that do not modify the SP are ignored,
   except for noreturn calls.

   The return value is the amount of adjustment that can be trivially
   verified, via immediate operand or auto-inc.  If the adjustment
   cannot be trivially extracted, the return value is INT_MIN.  */

HOST_WIDE_INT
find_args_size_adjust (rtx_insn *insn)
{
  rtx dest, set, pat;
  int i;

  pat = PATTERN (insn);
  set = NULL;

  /* Look for a call_pop pattern.  */
  if (CALL_P (insn))
    {
      /* We have to allow non-call_pop patterns for the case
         of emit_single_push_insn of a TLS address.  */
      if (GET_CODE (pat) != PARALLEL)
        return 0;

      /* All call_pop have a stack pointer adjust in the parallel.
         The call itself is always first, and the stack adjust is
         usually last, so search from the end.  */
      for (i = XVECLEN (pat, 0) - 1; i > 0; --i)
        {
          set = XVECEXP (pat, 0, i);
          if (GET_CODE (set) != SET)
            continue;
          dest = SET_DEST (set);
          if (dest == stack_pointer_rtx)
            break;
        }
      /* We'd better have found the stack pointer adjust.  */
      if (i == 0)
        return 0;
      /* Fall through to process the extracted SET and DEST
         as if it was a standalone insn.  */
    }
  else if (GET_CODE (pat) == SET)
    set = pat;
  else if ((set = single_set (insn)) != NULL)
    ;
  else if (GET_CODE (pat) == PARALLEL)
    {
      /* ??? Some older ports use a parallel with a stack adjust
         and a store for a PUSH_ROUNDING pattern, rather than a
         PRE/POST_MODIFY rtx.  Don't force them to update yet...  */
      /* ??? See h8300 and m68k, pushqi1.  */
      for (i = XVECLEN (pat, 0) - 1; i >= 0; --i)
        {
          set = XVECEXP (pat, 0, i);
          if (GET_CODE (set) != SET)
            continue;
          dest = SET_DEST (set);
          if (dest == stack_pointer_rtx)
            break;

          /* We do not expect an auto-inc of the sp in the parallel.  */
          gcc_checking_assert (mem_autoinc_base (dest) != stack_pointer_rtx);
          gcc_checking_assert (mem_autoinc_base (SET_SRC (set))
                               != stack_pointer_rtx);
        }
      if (i < 0)
        return 0;
    }
  else
    return 0;

  dest = SET_DEST (set);

  /* Look for direct modifications of the stack pointer.  */
  if (REG_P (dest) && REGNO (dest) == STACK_POINTER_REGNUM)
    {
      /* Look for a trivial adjustment, otherwise assume nothing.  */
      /* Note that the SPU restore_stack_block pattern refers to
         the stack pointer in V4SImode.  Consider that non-trivial.  */
      if (SCALAR_INT_MODE_P (GET_MODE (dest))
          && GET_CODE (SET_SRC (set)) == PLUS
          && XEXP (SET_SRC (set), 0) == stack_pointer_rtx
          && CONST_INT_P (XEXP (SET_SRC (set), 1)))
        return INTVAL (XEXP (SET_SRC (set), 1));
      /* ??? Reload can generate no-op moves, which will be cleaned
         up later.  Recognize it and continue searching.  */
      else if (rtx_equal_p (dest, SET_SRC (set)))
        return 0;
      else
        return HOST_WIDE_INT_MIN;
    }
  else
    {
      rtx mem, addr;

      /* Otherwise only think about autoinc patterns.  */
      if (mem_autoinc_base (dest) == stack_pointer_rtx)
        {
          mem = dest;
          gcc_checking_assert (mem_autoinc_base (SET_SRC (set))
                               != stack_pointer_rtx);
        }
      else if (mem_autoinc_base (SET_SRC (set)) == stack_pointer_rtx)
        mem = SET_SRC (set);
      else
        return 0;

      addr = XEXP (mem, 0);
      switch (GET_CODE (addr))
        {
        case PRE_INC:
        case POST_INC:
          return GET_MODE_SIZE (GET_MODE (mem));
        case PRE_DEC:
        case POST_DEC:
          return -GET_MODE_SIZE (GET_MODE (mem));
        case PRE_MODIFY:
        case POST_MODIFY:
          addr = XEXP (addr, 1);
          gcc_assert (GET_CODE (addr) == PLUS);
          gcc_assert (XEXP (addr, 0) == stack_pointer_rtx);
          gcc_assert (CONST_INT_P (XEXP (addr, 1)));
          return INTVAL (XEXP (addr, 1));
        default:
          gcc_unreachable ();
        }
    }
}

int
fixup_args_size_notes (rtx_insn *prev, rtx_insn *last, int end_args_size)
{
  int args_size = end_args_size;
  bool saw_unknown = false;
  rtx_insn *insn;

  for (insn = last; insn != prev; insn = PREV_INSN (insn))
    {
      HOST_WIDE_INT this_delta;

      if (!NONDEBUG_INSN_P (insn))
        continue;

      this_delta = find_args_size_adjust (insn);
      if (this_delta == 0)
        {
          if (!CALL_P (insn)
              || ACCUMULATE_OUTGOING_ARGS
              || find_reg_note (insn, REG_NORETURN, NULL_RTX) == NULL_RTX)
            continue;
        }

      gcc_assert (!saw_unknown);
      if (this_delta == HOST_WIDE_INT_MIN)
        saw_unknown = true;

      add_reg_note (insn, REG_ARGS_SIZE, GEN_INT (args_size));
#ifdef STACK_GROWS_DOWNWARD
      this_delta = -(unsigned HOST_WIDE_INT) this_delta;
#endif
      args_size -= this_delta;
    }

  return saw_unknown ? INT_MIN : args_size;
}

#ifdef PUSH_ROUNDING
/* Emit single push insn.  */

static void
emit_single_push_insn_1 (machine_mode mode, rtx x, tree type)
{
  rtx dest_addr;
  unsigned rounded_size = PUSH_ROUNDING (GET_MODE_SIZE (mode));
  rtx dest;
  enum insn_code icode;

  stack_pointer_delta += PUSH_ROUNDING (GET_MODE_SIZE (mode));
  /* If there is push pattern, use it.  Otherwise try old way of throwing
     MEM representing push operation to move expander.  */
  icode = optab_handler (push_optab, mode);
  if (icode != CODE_FOR_nothing)
    {
      struct expand_operand ops[1];

      create_input_operand (&ops[0], x, mode);
      if (maybe_expand_insn (icode, 1, ops))
        return;
    }
  if (GET_MODE_SIZE (mode) == rounded_size)
    dest_addr = gen_rtx_fmt_e (STACK_PUSH_CODE, Pmode, stack_pointer_rtx);
  /* If we are to pad downward, adjust the stack pointer first and
     then store X into the stack location using an offset.  This is
     because emit_move_insn does not know how to pad; it does not have
     access to type.  */
  else if (FUNCTION_ARG_PADDING (mode, type) == downward)
    {
      unsigned padding_size = rounded_size - GET_MODE_SIZE (mode);
      HOST_WIDE_INT offset;

      emit_move_insn (stack_pointer_rtx,
                      expand_binop (Pmode,
#ifdef STACK_GROWS_DOWNWARD
                                    sub_optab,
#else
                                    add_optab,
#endif
                                    stack_pointer_rtx,
                                    gen_int_mode (rounded_size, Pmode),
                                    NULL_RTX, 0, OPTAB_LIB_WIDEN));

      offset = (HOST_WIDE_INT) padding_size;
#ifdef STACK_GROWS_DOWNWARD
      if (STACK_PUSH_CODE == POST_DEC)
        /* We have already decremented the stack pointer, so get the
           previous value.  */
        offset += (HOST_WIDE_INT) rounded_size;
#else
      if (STACK_PUSH_CODE == POST_INC)
        /* We have already incremented the stack pointer, so get the
           previous value.  */
        offset -= (HOST_WIDE_INT) rounded_size;
#endif
      dest_addr = gen_rtx_PLUS (Pmode, stack_pointer_rtx,
                                gen_int_mode (offset, Pmode));
    }
  else
    {
#ifdef STACK_GROWS_DOWNWARD
      /* ??? This seems wrong if STACK_PUSH_CODE == POST_DEC.  */
      dest_addr = gen_rtx_PLUS (Pmode, stack_pointer_rtx,
                                gen_int_mode (-(HOST_WIDE_INT) rounded_size,
                                              Pmode));
#else
      /* ??? This seems wrong if STACK_PUSH_CODE == POST_INC.  */
      dest_addr = gen_rtx_PLUS (Pmode, stack_pointer_rtx,
                                gen_int_mode (rounded_size, Pmode));
#endif
      dest_addr = gen_rtx_PRE_MODIFY (Pmode, stack_pointer_rtx, dest_addr);
    }

  dest = gen_rtx_MEM (mode, dest_addr);

  if (type != 0)
    {
      set_mem_attributes (dest, type, 1);

      if (cfun->tail_call_marked)
        /* Function incoming arguments may overlap with sibling call
           outgoing arguments and we cannot allow reordering of reads
           from function arguments with stores to outgoing arguments
           of sibling calls.  */
        set_mem_alias_set (dest, 0);
    }
  emit_move_insn (dest, x);
}

/* Emit and annotate a single push insn.  */

static void
emit_single_push_insn (machine_mode mode, rtx x, tree type)
{
  int delta, old_delta = stack_pointer_delta;
  rtx_insn *prev = get_last_insn ();
  rtx_insn *last;

  emit_single_push_insn_1 (mode, x, type);

  last = get_last_insn ();

  /* Notice the common case where we emitted exactly one insn.  */
  if (PREV_INSN (last) == prev)
    {
      add_reg_note (last, REG_ARGS_SIZE, GEN_INT (stack_pointer_delta));
      return;
    }

  delta = fixup_args_size_notes (prev, last, stack_pointer_delta);
  gcc_assert (delta == INT_MIN || delta == old_delta);
}
#endif

/* Generate code to push X onto the stack, assuming it has mode MODE and
   type TYPE.
   MODE is redundant except when X is a CONST_INT (since they don't
   carry mode info).
   SIZE is an rtx for the size of data to be copied (in bytes),
   needed only if X is BLKmode.

   ALIGN (in bits) is maximum alignment we can assume.

   If PARTIAL and REG are both nonzero, then copy that many of the first
   bytes of X into registers starting with REG, and push the rest of X.
   The amount of space pushed is decreased by PARTIAL bytes.
   REG must be a hard register in this case.
   If REG is zero but PARTIAL is not, take any all others actions for an
   argument partially in registers, but do not actually load any
   registers.

   EXTRA is the amount in bytes of extra space to leave next to this arg.
   This is ignored if an argument block has already been allocated.

   On a machine that lacks real push insns, ARGS_ADDR is the address of
   the bottom of the argument block for this call.  We use indexing off there
   to store the arg.  On machines with push insns, ARGS_ADDR is 0 when a
   argument block has not been preallocated.

   ARGS_SO_FAR is the size of args previously pushed for this call.

   REG_PARM_STACK_SPACE is nonzero if functions require stack space
   for arguments passed in registers.  If nonzero, it will be the number
   of bytes required.  */

void
emit_push_insn (rtx x, machine_mode mode, tree type, rtx size,
                unsigned int align, int partial, rtx reg, int extra,
                rtx args_addr, rtx args_so_far, int reg_parm_stack_space,
                rtx alignment_pad)
{
  rtx xinner;
  enum direction stack_direction
#ifdef STACK_GROWS_DOWNWARD
    = downward;
#else
    = upward;
#endif

  /* Decide where to pad the argument: `downward' for below,
     `upward' for above, or `none' for don't pad it.
     Default is below for small data on big-endian machines; else above.  */
  enum direction where_pad = FUNCTION_ARG_PADDING (mode, type);

  /* Invert direction if stack is post-decrement.
     FIXME: why?  */
  if (STACK_PUSH_CODE == POST_DEC)
    if (where_pad != none)
      where_pad = (where_pad == downward ? upward : downward);

  xinner = x;

  if (mode == BLKmode
      || (STRICT_ALIGNMENT && align < GET_MODE_ALIGNMENT (mode)))
    {
      /* Copy a block into the stack, entirely or partially.  */

      rtx temp;
      int used;
      int offset;
      int skip;

      offset = partial % (PARM_BOUNDARY / BITS_PER_UNIT);
      used = partial - offset;

      if (mode != BLKmode)
        {
          /* A value is to be stored in an insufficiently aligned
             stack slot; copy via a suitably aligned slot if
             necessary.  */
          size = GEN_INT (GET_MODE_SIZE (mode));
          if (!MEM_P (xinner))
            {
              temp = assign_temp (type, 1, 1);
              emit_move_insn (temp, xinner);
              xinner = temp;
            }
        }

      gcc_assert (size);

      /* USED is now the # of bytes we need not copy to the stack
         because registers will take care of them.  */

      if (partial != 0)
        xinner = adjust_address (xinner, BLKmode, used);

      /* If the partial register-part of the arg counts in its stack size,
         skip the part of stack space corresponding to the registers.
         Otherwise, start copying to the beginning of the stack space,
         by setting SKIP to 0.  */
      skip = (reg_parm_stack_space == 0) ? 0 : used;

#ifdef PUSH_ROUNDING
      /* Do it with several push insns if that doesn't take lots of insns
         and if there is no difficulty with push insns that skip bytes
         on the stack for alignment purposes.  */
      if (args_addr == 0
          && PUSH_ARGS
          && CONST_INT_P (size)
          && skip == 0
          && MEM_ALIGN (xinner) >= align
          && (MOVE_BY_PIECES_P ((unsigned) INTVAL (size) - used, align))
          /* Here we avoid the case of a structure whose weak alignment
             forces many pushes of a small amount of data,
             and such small pushes do rounding that causes trouble.  */
          && ((! SLOW_UNALIGNED_ACCESS (word_mode, align))
              || align >= BIGGEST_ALIGNMENT
              || (PUSH_ROUNDING (align / BITS_PER_UNIT)
                  == (align / BITS_PER_UNIT)))
          && (HOST_WIDE_INT) PUSH_ROUNDING (INTVAL (size)) == INTVAL (size))
        {
          /* Push padding now if padding above and stack grows down,
             or if padding below and stack grows up.
             But if space already allocated, this has already been done.  */
          if (extra && args_addr == 0
              && where_pad != none && where_pad != stack_direction)
            anti_adjust_stack (GEN_INT (extra));

          move_by_pieces (NULL, xinner, INTVAL (size) - used, align, 0);
        }
      else
#endif /* PUSH_ROUNDING  */
        {
          rtx target;

          /* Otherwise make space on the stack and copy the data
             to the address of that space.  */

          /* Deduct words put into registers from the size we must copy.  */
          if (partial != 0)
            {
              if (CONST_INT_P (size))
                size = GEN_INT (INTVAL (size) - used);
              else
                size = expand_binop (GET_MODE (size), sub_optab, size,
                                     gen_int_mode (used, GET_MODE (size)),
                                     NULL_RTX, 0, OPTAB_LIB_WIDEN);
            }

          /* Get the address of the stack space.
             In this case, we do not deal with EXTRA separately.
             A single stack adjust will do.  */
          if (! args_addr)
            {
              temp = push_block (size, extra, where_pad == downward);
              extra = 0;
            }
          else if (CONST_INT_P (args_so_far))
            temp = memory_address (BLKmode,
                                   plus_constant (Pmode, args_addr,
                                                  skip + INTVAL (args_so_far)));
          else
            temp = memory_address (BLKmode,
                                   plus_constant (Pmode,
                                                  gen_rtx_PLUS (Pmode,
                                                                args_addr,
                                                                args_so_far),
                                                  skip));

          if (!ACCUMULATE_OUTGOING_ARGS)
            {
              /* If the source is referenced relative to the stack pointer,
                 copy it to another register to stabilize it.  We do not need
                 to do this if we know that we won't be changing sp.  */

              if (reg_mentioned_p (virtual_stack_dynamic_rtx, temp)
                  || reg_mentioned_p (virtual_outgoing_args_rtx, temp))
                temp = copy_to_reg (temp);
            }

          target = gen_rtx_MEM (BLKmode, temp);

          /* We do *not* set_mem_attributes here, because incoming arguments
             may overlap with sibling call outgoing arguments and we cannot
             allow reordering of reads from function arguments with stores
             to outgoing arguments of sibling calls.  We do, however, want
             to record the alignment of the stack slot.  */
          /* ALIGN may well be better aligned than TYPE, e.g. due to
             PARM_BOUNDARY.  Assume the caller isn't lying.  */
          set_mem_align (target, align);

          emit_block_move (target, xinner, size, BLOCK_OP_CALL_PARM);
        }
    }
  else if (partial > 0)
    {
      /* Scalar partly in registers.  */

      int size = GET_MODE_SIZE (mode) / UNITS_PER_WORD;
      int i;
      int not_stack;
      /* # bytes of start of argument
         that we must make space for but need not store.  */
      int offset = partial % (PARM_BOUNDARY / BITS_PER_UNIT);
      int args_offset = INTVAL (args_so_far);
      int skip;

      /* Push padding now if padding above and stack grows down,
         or if padding below and stack grows up.
         But if space already allocated, this has already been done.  */
      if (extra && args_addr == 0
          && where_pad != none && where_pad != stack_direction)
        anti_adjust_stack (GEN_INT (extra));

      /* If we make space by pushing it, we might as well push
         the real data.  Otherwise, we can leave OFFSET nonzero
         and leave the space uninitialized.  */
      if (args_addr == 0)
        offset = 0;

      /* Now NOT_STACK gets the number of words that we don't need to
         allocate on the stack.  Convert OFFSET to words too.  */
      not_stack = (partial - offset) / UNITS_PER_WORD;
      offset /= UNITS_PER_WORD;

      /* If the partial register-part of the arg counts in its stack size,
         skip the part of stack space corresponding to the registers.
         Otherwise, start copying to the beginning of the stack space,
         by setting SKIP to 0.  */
      skip = (reg_parm_stack_space == 0) ? 0 : not_stack;

      if (CONSTANT_P (x) && !targetm.legitimate_constant_p (mode, x))
        x = validize_mem (force_const_mem (mode, x));

      /* If X is a hard register in a non-integer mode, copy it into a pseudo;
         SUBREGs of such registers are not allowed.  */
      if ((REG_P (x) && REGNO (x) < FIRST_PSEUDO_REGISTER
           && GET_MODE_CLASS (GET_MODE (x)) != MODE_INT))
        x = copy_to_reg (x);

      /* Loop over all the words allocated on the stack for this arg.  */
      /* We can do it by words, because any scalar bigger than a word
         has a size a multiple of a word.  */
      for (i = size - 1; i >= not_stack; i--)
        if (i >= not_stack + offset)
          emit_push_insn (operand_subword_force (x, i, mode),
                          word_mode, NULL_TREE, NULL_RTX, align, 0, NULL_RTX,
                          0, args_addr,
                          GEN_INT (args_offset + ((i - not_stack + skip)
                                                  * UNITS_PER_WORD)),
                          reg_parm_stack_space, alignment_pad);
    }
  else
    {
      rtx addr;
      rtx dest;

      /* Push padding now if padding above and stack grows down,
         or if padding below and stack grows up.
         But if space already allocated, this has already been done.  */
      if (extra && args_addr == 0
          && where_pad != none && where_pad != stack_direction)
        anti_adjust_stack (GEN_INT (extra));

#ifdef PUSH_ROUNDING
      if (args_addr == 0 && PUSH_ARGS)
        emit_single_push_insn (mode, x, type);
      else
#endif
        {
          if (CONST_INT_P (args_so_far))
            addr
              = memory_address (mode,
                                plus_constant (Pmode, args_addr,
                                               INTVAL (args_so_far)));
          else
            addr = memory_address (mode, gen_rtx_PLUS (Pmode, args_addr,
                                                       args_so_far));
          dest = gen_rtx_MEM (mode, addr);

          /* We do *not* set_mem_attributes here, because incoming arguments
             may overlap with sibling call outgoing arguments and we cannot
             allow reordering of reads from function arguments with stores
             to outgoing arguments of sibling calls.  We do, however, want
             to record the alignment of the stack slot.  */
          /* ALIGN may well be better aligned than TYPE, e.g. due to
             PARM_BOUNDARY.  Assume the caller isn't lying.  */
          set_mem_align (dest, align);

          emit_move_insn (dest, x);
        }
    }

  /* If part should go in registers, copy that part
     into the appropriate registers.  Do this now, at the end,
     since mem-to-mem copies above may do function calls.  */
  if (partial > 0 && reg != 0)
    {
      /* Handle calls that pass values in multiple non-contiguous locations.
         The Irix 6 ABI has examples of this.  */
      if (GET_CODE (reg) == PARALLEL)
        emit_group_load (reg, x, type, -1);
      else
        {
          gcc_assert (partial % UNITS_PER_WORD == 0);
          move_block_to_reg (REGNO (reg), x, partial / UNITS_PER_WORD, mode);
        }
    }

  if (extra && args_addr == 0 && where_pad == stack_direction)
    anti_adjust_stack (GEN_INT (extra));

  if (alignment_pad && args_addr == 0)
    anti_adjust_stack (alignment_pad);
}
\f
/* Return X if X can be used as a subtarget in a sequence of arithmetic
   operations.  */

static rtx
get_subtarget (rtx x)
{
  return (optimize
          || x == 0
           /* Only registers can be subtargets.  */
           || !REG_P (x)
           /* Don't use hard regs to avoid extending their life.  */
           || REGNO (x) < FIRST_PSEUDO_REGISTER
          ? 0 : x);
}

/* A subroutine of expand_assignment.  Optimize FIELD op= VAL, where
   FIELD is a bitfield.  Returns true if the optimization was successful,
   and there's nothing else to do.  */

static bool
optimize_bitfield_assignment_op (unsigned HOST_WIDE_INT bitsize,
                                 unsigned HOST_WIDE_INT bitpos,
                                 unsigned HOST_WIDE_INT bitregion_start,
                                 unsigned HOST_WIDE_INT bitregion_end,
                                 machine_mode mode1, rtx str_rtx,
                                 tree to, tree src)
{
  machine_mode str_mode = GET_MODE (str_rtx);
  unsigned int str_bitsize = GET_MODE_BITSIZE (str_mode);
  tree op0, op1;
  rtx value, result;
  optab binop;
  gimple srcstmt;
  enum tree_code code;

  if (mode1 != VOIDmode
      || bitsize >= BITS_PER_WORD
      || str_bitsize > BITS_PER_WORD
      || TREE_SIDE_EFFECTS (to)
      || TREE_THIS_VOLATILE (to))
    return false;

  STRIP_NOPS (src);
  if (TREE_CODE (src) != SSA_NAME)
    return false;
  if (TREE_CODE (TREE_TYPE (src)) != INTEGER_TYPE)
    return false;

  srcstmt = get_gimple_for_ssa_name (src);
  if (!srcstmt
      || TREE_CODE_CLASS (gimple_assign_rhs_code (srcstmt)) != tcc_binary)
    return false;

  code = gimple_assign_rhs_code (srcstmt);

  op0 = gimple_assign_rhs1 (srcstmt);

  /* If OP0 is an SSA_NAME, then we want to walk the use-def chain
     to find its initialization.  Hopefully the initialization will
     be from a bitfield load.  */
  if (TREE_CODE (op0) == SSA_NAME)
    {
      gimple op0stmt = get_gimple_for_ssa_name (op0);

      /* We want to eventually have OP0 be the same as TO, which
         should be a bitfield.  */
      if (!op0stmt
          || !is_gimple_assign (op0stmt)
          || gimple_assign_rhs_code (op0stmt) != TREE_CODE (to))
        return false;
      op0 = gimple_assign_rhs1 (op0stmt);
    }

  op1 = gimple_assign_rhs2 (srcstmt);

  if (!operand_equal_p (to, op0, 0))
    return false;

  if (MEM_P (str_rtx))
    {
      unsigned HOST_WIDE_INT offset1;

      if (str_bitsize == 0 || str_bitsize > BITS_PER_WORD)
        str_mode = word_mode;
      str_mode = get_best_mode (bitsize, bitpos,
                                bitregion_start, bitregion_end,
                                MEM_ALIGN (str_rtx), str_mode, 0);
      if (str_mode == VOIDmode)
        return false;
      str_bitsize = GET_MODE_BITSIZE (str_mode);

      offset1 = bitpos;
      bitpos %= str_bitsize;
      offset1 = (offset1 - bitpos) / BITS_PER_UNIT;
      str_rtx = adjust_address (str_rtx, str_mode, offset1);
    }
  else if (!REG_P (str_rtx) && GET_CODE (str_rtx) != SUBREG)
    return false;

  /* If the bit field covers the whole REG/MEM, store_field
     will likely generate better code.  */
  if (bitsize >= str_bitsize)
    return false;

  /* We can't handle fields split across multiple entities.  */
  if (bitpos + bitsize > str_bitsize)
    return false;

  if (BYTES_BIG_ENDIAN)
    bitpos = str_bitsize - bitpos - bitsize;

  switch (code)
    {
    case PLUS_EXPR:
    case MINUS_EXPR:
      /* For now, just optimize the case of the topmost bitfield
         where we don't need to do any masking and also
         1 bit bitfields where xor can be used.
         We might win by one instruction for the other bitfields
         too if insv/extv instructions aren't used, so that
         can be added later.  */
      if (bitpos + bitsize != str_bitsize
          && (bitsize != 1 || TREE_CODE (op1) != INTEGER_CST))
        break;

      value = expand_expr (op1, NULL_RTX, str_mode, EXPAND_NORMAL);
      value = convert_modes (str_mode,
                             TYPE_MODE (TREE_TYPE (op1)), value,
                             TYPE_UNSIGNED (TREE_TYPE (op1)));

      /* We may be accessing data outside the field, which means
         we can alias adjacent data.  */
      if (MEM_P (str_rtx))
        {
          str_rtx = shallow_copy_rtx (str_rtx);
          set_mem_alias_set (str_rtx, 0);
          set_mem_expr (str_rtx, 0);
        }

      binop = code == PLUS_EXPR ? add_optab : sub_optab;
      if (bitsize == 1 && bitpos + bitsize != str_bitsize)
        {
          value = expand_and (str_mode, value, const1_rtx, NULL);
          binop = xor_optab;
        }
      value = expand_shift (LSHIFT_EXPR, str_mode, value, bitpos, NULL_RTX, 1);
      result = expand_binop (str_mode, binop, str_rtx,
                             value, str_rtx, 1, OPTAB_WIDEN);
      if (result != str_rtx)
        emit_move_insn (str_rtx, result);
      return true;

    case BIT_IOR_EXPR:
    case BIT_XOR_EXPR:
      if (TREE_CODE (op1) != INTEGER_CST)
        break;
      value = expand_expr (op1, NULL_RTX, str_mode, EXPAND_NORMAL);
      value = convert_modes (str_mode,
                             TYPE_MODE (TREE_TYPE (op1)), value,
                             TYPE_UNSIGNED (TREE_TYPE (op1)));

      /* We may be accessing data outside the field, which means
         we can alias adjacent data.  */
      if (MEM_P (str_rtx))
        {
          str_rtx = shallow_copy_rtx (str_rtx);
          set_mem_alias_set (str_rtx, 0);
          set_mem_expr (str_rtx, 0);
        }

      binop = code == BIT_IOR_EXPR ? ior_optab : xor_optab;
      if (bitpos + bitsize != str_bitsize)
        {
          rtx mask = gen_int_mode (((unsigned HOST_WIDE_INT) 1 << bitsize) - 1,
                                   str_mode);
          value = expand_and (str_mode, value, mask, NULL_RTX);
        }
      value = expand_shift (LSHIFT_EXPR, str_mode, value, bitpos, NULL_RTX, 1);
      result = expand_binop (str_mode, binop, str_rtx,
                             value, str_rtx, 1, OPTAB_WIDEN);
      if (result != str_rtx)
        emit_move_insn (str_rtx, result);
      return true;

    default:
      break;
    }

  return false;
}

/* In the C++ memory model, consecutive bit fields in a structure are
   considered one memory location.

   Given a COMPONENT_REF EXP at position (BITPOS, OFFSET), this function
   returns the bit range of consecutive bits in which this COMPONENT_REF
   belongs.  The values are returned in *BITSTART and *BITEND.  *BITPOS
   and *OFFSET may be adjusted in the process.

   If the access does not need to be restricted, 0 is returned in both
   *BITSTART and *BITEND.  */

static void
get_bit_range (unsigned HOST_WIDE_INT *bitstart,
               unsigned HOST_WIDE_INT *bitend,
               tree exp,
               HOST_WIDE_INT *bitpos,
               tree *offset)
{
  HOST_WIDE_INT bitoffset;
  tree field, repr;

  gcc_assert (TREE_CODE (exp) == COMPONENT_REF);

  field = TREE_OPERAND (exp, 1);
  repr = DECL_BIT_FIELD_REPRESENTATIVE (field);
  /* If we do not have a DECL_BIT_FIELD_REPRESENTATIVE there is no
     need to limit the range we can access.  */
  if (!repr)
    {
      *bitstart = *bitend = 0;
      return;
    }

  /* If we have a DECL_BIT_FIELD_REPRESENTATIVE but the enclosing record is
     part of a larger bit field, then the representative does not serve any
     useful purpose.  This can occur in Ada.  */
  if (handled_component_p (TREE_OPERAND (exp, 0)))
    {
      machine_mode rmode;
      HOST_WIDE_INT rbitsize, rbitpos;
      tree roffset;
      int unsignedp;
      int volatilep = 0;
      get_inner_reference (TREE_OPERAND (exp, 0), &rbitsize, &rbitpos,
                           &roffset, &rmode, &unsignedp, &volatilep, false);
      if ((rbitpos % BITS_PER_UNIT) != 0)
        {
          *bitstart = *bitend = 0;
          return;
        }
    }

  /* Compute the adjustment to bitpos from the offset of the field
     relative to the representative.  DECL_FIELD_OFFSET of field and
     repr are the same by construction if they are not constants,
     see finish_bitfield_layout.  */
  if (tree_fits_uhwi_p (DECL_FIELD_OFFSET (field))
      && tree_fits_uhwi_p (DECL_FIELD_OFFSET (repr)))
    bitoffset = (tree_to_uhwi (DECL_FIELD_OFFSET (field))
                 - tree_to_uhwi (DECL_FIELD_OFFSET (repr))) * BITS_PER_UNIT;
  else
    bitoffset = 0;
  bitoffset += (tree_to_uhwi (DECL_FIELD_BIT_OFFSET (field))
                - tree_to_uhwi (DECL_FIELD_BIT_OFFSET (repr)));

  /* If the adjustment is larger than bitpos, we would have a negative bit
     position for the lower bound and this may wreak havoc later.  Adjust
     offset and bitpos to make the lower bound non-negative in that case.  */
  if (bitoffset > *bitpos)
    {
      HOST_WIDE_INT adjust = bitoffset - *bitpos;
      gcc_assert ((adjust % BITS_PER_UNIT) == 0);

      *bitpos += adjust;
      if (*offset == NULL_TREE)
        *offset = size_int (-adjust / BITS_PER_UNIT);
      else
        *offset
          = size_binop (MINUS_EXPR, *offset, size_int (adjust / BITS_PER_UNIT));
      *bitstart = 0;
    }
  else
    *bitstart = *bitpos - bitoffset;

  *bitend = *bitstart + tree_to_uhwi (DECL_SIZE (repr)) - 1;
}

/* Returns true if ADDR is an ADDR_EXPR of a DECL that does not reside
   in memory and has non-BLKmode.  DECL_RTL must not be a MEM; if
   DECL_RTL was not set yet, return NORTL.  */

static inline bool
addr_expr_of_non_mem_decl_p_1 (tree addr, bool nortl)
{
  if (TREE_CODE (addr) != ADDR_EXPR)
    return false;

  tree base = TREE_OPERAND (addr, 0);

  if (!DECL_P (base)
      || TREE_ADDRESSABLE (base)
      || DECL_MODE (base) == BLKmode)
    return false;

  if (!DECL_RTL_SET_P (base))
    return nortl;

  return (!MEM_P (DECL_RTL (base)));
}

/* Returns true if the MEM_REF REF refers to an object that does not
   reside in memory and has non-BLKmode.  */

static inline bool
mem_ref_refers_to_non_mem_p (tree ref)
{
  tree base = TREE_OPERAND (ref, 0);
  return addr_expr_of_non_mem_decl_p_1 (base, false);
}

/* Expand an assignment that stores the value of FROM into TO.  If NONTEMPORAL
   is true, try generating a nontemporal store.  */

void
expand_assignment (tree to, tree from, bool nontemporal)
{
  rtx to_rtx = 0;
  rtx result;
  machine_mode mode;
  unsigned int align;
  enum insn_code icode;

  /* Don't crash if the lhs of the assignment was erroneous.  */
  if (TREE_CODE (to) == ERROR_MARK)
    {
      expand_normal (from);
      return;
    }

  /* Optimize away no-op moves without side-effects.  */
  if (operand_equal_p (to, from, 0))
    return;

  /* Handle misaligned stores.  */
  mode = TYPE_MODE (TREE_TYPE (to));
  if ((TREE_CODE (to) == MEM_REF
       || TREE_CODE (to) == TARGET_MEM_REF)
      && mode != BLKmode
      && !mem_ref_refers_to_non_mem_p (to)
      && ((align = get_object_alignment (to))
          < GET_MODE_ALIGNMENT (mode))
      && (((icode = optab_handler (movmisalign_optab, mode))
           != CODE_FOR_nothing)
          || SLOW_UNALIGNED_ACCESS (mode, align)))
    {
      rtx reg, mem;

      reg = expand_expr (from, NULL_RTX, VOIDmode, EXPAND_NORMAL);
      reg = force_not_mem (reg);
      mem = expand_expr (to, NULL_RTX, VOIDmode, EXPAND_WRITE);

      if (icode != CODE_FOR_nothing)
        {
          struct expand_operand ops[2];

          create_fixed_operand (&ops[0], mem);
          create_input_operand (&ops[1], reg, mode);
          /* The movmisalign<mode> pattern cannot fail, else the assignment
             would silently be omitted.  */
          expand_insn (icode, 2, ops);
        }
      else
        store_bit_field (mem, GET_MODE_BITSIZE (mode), 0, 0, 0, mode, reg);
      return;
    }

  /* Assignment of a structure component needs special treatment
     if the structure component's rtx is not simply a MEM.
     Assignment of an array element at a constant index, and assignment of
     an array element in an unaligned packed structure field, has the same
     problem.  Same for (partially) storing into a non-memory object.  */
  if (handled_component_p (to)
      || (TREE_CODE (to) == MEM_REF
          && mem_ref_refers_to_non_mem_p (to))
      || TREE_CODE (TREE_TYPE (to)) == ARRAY_TYPE)
    {
      machine_mode mode1;
      HOST_WIDE_INT bitsize, bitpos;
      unsigned HOST_WIDE_INT bitregion_start = 0;
      unsigned HOST_WIDE_INT bitregion_end = 0;
      tree offset;
      int unsignedp;
      int volatilep = 0;
      tree tem;

      push_temp_slots ();
      tem = get_inner_reference (to, &bitsize, &bitpos, &offset, &mode1,
                                 &unsignedp, &volatilep, true);

      /* Make sure bitpos is not negative, it can wreak havoc later.  */
      if (bitpos < 0)
        {
          gcc_assert (offset == NULL_TREE);
          offset = size_int (bitpos >> (BITS_PER_UNIT == 8
                                        ? 3 : exact_log2 (BITS_PER_UNIT)));
          bitpos &= BITS_PER_UNIT - 1;
        }

      if (TREE_CODE (to) == COMPONENT_REF
          && DECL_BIT_FIELD_TYPE (TREE_OPERAND (to, 1)))
        get_bit_range (&bitregion_start, &bitregion_end, to, &bitpos, &offset);
      /* The C++ memory model naturally applies to byte-aligned fields.
         However, if we do not have a DECL_BIT_FIELD_TYPE but BITPOS or
         BITSIZE are not byte-aligned, there is no need to limit the range
         we can access.  This can occur with packed structures in Ada.  */
      else if (bitsize > 0
               && bitsize % BITS_PER_UNIT == 0
               && bitpos % BITS_PER_UNIT == 0)
        {
          bitregion_start = bitpos;
          bitregion_end = bitpos + bitsize - 1;
        }

      to_rtx = expand_expr (tem, NULL_RTX, VOIDmode, EXPAND_WRITE);

      /* If the field has a mode, we want to access it in the
         field's mode, not the computed mode.
         If a MEM has VOIDmode (external with incomplete type),
         use BLKmode for it instead.  */
      if (MEM_P (to_rtx))
        {
          if (mode1 != VOIDmode)
            to_rtx = adjust_address (to_rtx, mode1, 0);
          else if (GET_MODE (to_rtx) == VOIDmode)
            to_rtx = adjust_address (to_rtx, BLKmode, 0);
        }
 
      if (offset != 0)
        {
          machine_mode address_mode;
          rtx offset_rtx;

          if (!MEM_P (to_rtx))
            {
              /* We can get constant negative offsets into arrays with broken
                 user code.  Translate this to a trap instead of ICEing.  */
              gcc_assert (TREE_CODE (offset) == INTEGER_CST);
              expand_builtin_trap ();
              to_rtx = gen_rtx_MEM (BLKmode, const0_rtx);
            }

          offset_rtx = expand_expr (offset, NULL_RTX, VOIDmode, EXPAND_SUM);
          address_mode = get_address_mode (to_rtx);
          if (GET_MODE (offset_rtx) != address_mode)
            offset_rtx = convert_to_mode (address_mode, offset_rtx, 0);

          /* If we have an expression in OFFSET_RTX and a non-zero
             byte offset in BITPOS, adding the byte offset before the
             OFFSET_RTX results in better intermediate code, which makes
             later rtl optimization passes perform better.

             We prefer intermediate code like this:

             r124:DI=r123:DI+0x18
             [r124:DI]=r121:DI

             ... instead of ...

             r124:DI=r123:DI+0x10
             [r124:DI+0x8]=r121:DI

             This is only done for aligned data values, as these can
             be expected to result in single move instructions.  */
          if (mode1 != VOIDmode
              && bitpos != 0
              && bitsize > 0
              && (bitpos % bitsize) == 0
              && (bitsize % GET_MODE_ALIGNMENT (mode1)) == 0
              && MEM_ALIGN (to_rtx) >= GET_MODE_ALIGNMENT (mode1))
            {
              to_rtx = adjust_address (to_rtx, mode1, bitpos / BITS_PER_UNIT);
              bitregion_start = 0;
              if (bitregion_end >= (unsigned HOST_WIDE_INT) bitpos)
                bitregion_end -= bitpos;
              bitpos = 0;
            }

          to_rtx = offset_address (to_rtx, offset_rtx,
                                   highest_pow2_factor_for_target (to,
                                                                   offset));
        }

      /* No action is needed if the target is not a memory and the field
         lies completely outside that target.  This can occur if the source
         code contains an out-of-bounds access to a small array.  */
      if (!MEM_P (to_rtx)
          && GET_MODE (to_rtx) != BLKmode
          && (unsigned HOST_WIDE_INT) bitpos
             >= GET_MODE_PRECISION (GET_MODE (to_rtx)))
        {
          expand_normal (from);
          result = NULL;
        }
      /* Handle expand_expr of a complex value returning a CONCAT.  */
      else if (GET_CODE (to_rtx) == CONCAT)
        {
          unsigned short mode_bitsize = GET_MODE_BITSIZE (GET_MODE (to_rtx));
          if (COMPLEX_MODE_P (TYPE_MODE (TREE_TYPE (from)))
              && bitpos == 0
              && bitsize == mode_bitsize)
            result = store_expr (from, to_rtx, false, nontemporal);
          else if (bitsize == mode_bitsize / 2
                   && (bitpos == 0 || bitpos == mode_bitsize / 2))
            result = store_expr (from, XEXP (to_rtx, bitpos != 0), false,
                                 nontemporal);
          else if (bitpos + bitsize <= mode_bitsize / 2)
            result = store_field (XEXP (to_rtx, 0), bitsize, bitpos,
                                  bitregion_start, bitregion_end,
                                  mode1, from,
                                  get_alias_set (to), nontemporal);
          else if (bitpos >= mode_bitsize / 2)
            result = store_field (XEXP (to_rtx, 1), bitsize,
                                  bitpos - mode_bitsize / 2,
                                  bitregion_start, bitregion_end,
                                  mode1, from,
                                  get_alias_set (to), nontemporal);
          else if (bitpos == 0 && bitsize == mode_bitsize)
            {
              rtx from_rtx;
              result = expand_normal (from);
              from_rtx = simplify_gen_subreg (GET_MODE (to_rtx), result,
                                              TYPE_MODE (TREE_TYPE (from)), 0);
              emit_move_insn (XEXP (to_rtx, 0),
                              read_complex_part (from_rtx, false));
              emit_move_insn (XEXP (to_rtx, 1),
                              read_complex_part (from_rtx, true));
            }
          else
            {
              rtx temp = assign_stack_temp (GET_MODE (to_rtx),
                                            GET_MODE_SIZE (GET_MODE (to_rtx)));
              write_complex_part (temp, XEXP (to_rtx, 0), false);
              write_complex_part (temp, XEXP (to_rtx, 1), true);
              result = store_field (temp, bitsize, bitpos,
                                    bitregion_start, bitregion_end,
                                    mode1, from,
                                    get_alias_set (to), nontemporal);
              emit_move_insn (XEXP (to_rtx, 0), read_complex_part (temp, false));
              emit_move_insn (XEXP (to_rtx, 1), read_complex_part (temp, true));
            }
        }
      else
        {
          if (MEM_P (to_rtx))
            {
              /* If the field is at offset zero, we could have been given the
                 DECL_RTX of the parent struct.  Don't munge it.  */
              to_rtx = shallow_copy_rtx (to_rtx);
              set_mem_attributes_minus_bitpos (to_rtx, to, 0, bitpos);
              if (volatilep)
                MEM_VOLATILE_P (to_rtx) = 1;
            }

          if (optimize_bitfield_assignment_op (bitsize, bitpos,
                                               bitregion_start, bitregion_end,
                                               mode1,
                                               to_rtx, to, from))
            result = NULL;
          else
            result = store_field (to_rtx, bitsize, bitpos,
                                  bitregion_start, bitregion_end,
                                  mode1, from,
                                  get_alias_set (to), nontemporal);
        }

      if (result)
        preserve_temp_slots (result);
      pop_temp_slots ();
      return;
    }

  /* If the rhs is a function call and its value is not an aggregate,
     call the function before we start to compute the lhs.
     This is needed for correct code for cases such as
     val = setjmp (buf) on machines where reference to val
     requires loading up part of an address in a separate insn.

     Don't do this if TO is a VAR_DECL or PARM_DECL whose DECL_RTL is REG
     since it might be a promoted variable where the zero- or sign- extension
     needs to be done.  Handling this in the normal way is safe because no
     computation is done before the call.  The same is true for SSA names.  */
  if (TREE_CODE (from) == CALL_EXPR && ! aggregate_value_p (from, from)
      && COMPLETE_TYPE_P (TREE_TYPE (from))
      && TREE_CODE (TYPE_SIZE (TREE_TYPE (from))) == INTEGER_CST
      && ! (((TREE_CODE (to) == VAR_DECL
              || TREE_CODE (to) == PARM_DECL
              || TREE_CODE (to) == RESULT_DECL)
             && REG_P (DECL_RTL (to)))
            || TREE_CODE (to) == SSA_NAME))
    {
      rtx value;

      push_temp_slots ();
      value = expand_normal (from);
      if (to_rtx == 0)
        to_rtx = expand_expr (to, NULL_RTX, VOIDmode, EXPAND_WRITE);

      /* Handle calls that return values in multiple non-contiguous locations.
         The Irix 6 ABI has examples of this.  */
      if (GET_CODE (to_rtx) == PARALLEL)
        {
          if (GET_CODE (value) == PARALLEL)
            emit_group_move (to_rtx, value);
          else
            emit_group_load (to_rtx, value, TREE_TYPE (from),
                             int_size_in_bytes (TREE_TYPE (from)));
        }
      else if (GET_CODE (value) == PARALLEL)
        emit_group_store (to_rtx, value, TREE_TYPE (from),
                          int_size_in_bytes (TREE_TYPE (from)));
      else if (GET_MODE (to_rtx) == BLKmode)
        {
          /* Handle calls that return BLKmode values in registers.  */
          if (REG_P (value))
            copy_blkmode_from_reg (to_rtx, value, TREE_TYPE (from));
          else
            emit_block_move (to_rtx, value, expr_size (from), BLOCK_OP_NORMAL);
        }
      else
        {
          if (POINTER_TYPE_P (TREE_TYPE (to)))
            value = convert_memory_address_addr_space
                      (GET_MODE (to_rtx), value,
                       TYPE_ADDR_SPACE (TREE_TYPE (TREE_TYPE (to))));

          emit_move_insn (to_rtx, value);
        }
      preserve_temp_slots (to_rtx);
      pop_temp_slots ();
      return;
    }

  /* Ordinary treatment.  Expand TO to get a REG or MEM rtx.  */
  to_rtx = expand_expr (to, NULL_RTX, VOIDmode, EXPAND_WRITE);

  /* Don't move directly into a return register.  */
  if (TREE_CODE (to) == RESULT_DECL
      && (REG_P (to_rtx) || GET_CODE (to_rtx) == PARALLEL))
    {
      rtx temp;

      push_temp_slots ();

      /* If the source is itself a return value, it still is in a pseudo at
         this point so we can move it back to the return register directly.  */
      if (REG_P (to_rtx)
          && TYPE_MODE (TREE_TYPE (from)) == BLKmode
          && TREE_CODE (from) != CALL_EXPR)
        temp = copy_blkmode_to_reg (GET_MODE (to_rtx), from);
      else
        temp = expand_expr (from, NULL_RTX, GET_MODE (to_rtx), EXPAND_NORMAL);

      /* Handle calls that return values in multiple non-contiguous locations.
         The Irix 6 ABI has examples of this.  */
      if (GET_CODE (to_rtx) == PARALLEL)
        {
          if (GET_CODE (temp) == PARALLEL)
            emit_group_move (to_rtx, temp);
          else
            emit_group_load (to_rtx, temp, TREE_TYPE (from),
                             int_size_in_bytes (TREE_TYPE (from)));
        }
      else if (temp)
        emit_move_insn (to_rtx, temp);

      preserve_temp_slots (to_rtx);
      pop_temp_slots ();
      return;
    }

  /* In case we are returning the contents of an object which overlaps
     the place the value is being stored, use a safe function when copying
     a value through a pointer into a structure value return block.  */
  if (TREE_CODE (to) == RESULT_DECL
      && TREE_CODE (from) == INDIRECT_REF
      && ADDR_SPACE_GENERIC_P
           (TYPE_ADDR_SPACE (TREE_TYPE (TREE_TYPE (TREE_OPERAND (from, 0)))))
      && refs_may_alias_p (to, from)
      && cfun->returns_struct
      && !cfun->returns_pcc_struct)
    {
      rtx from_rtx, size;

      push_temp_slots ();
      size = expr_size (from);
      from_rtx = expand_normal (from);

      emit_library_call (memmove_libfunc, LCT_NORMAL,
                         VOIDmode, 3, XEXP (to_rtx, 0), Pmode,
                         XEXP (from_rtx, 0), Pmode,
                         convert_to_mode (TYPE_MODE (sizetype),
                                          size, TYPE_UNSIGNED (sizetype)),
                         TYPE_MODE (sizetype));

      preserve_temp_slots (to_rtx);
      pop_temp_slots ();
      return;
    }

  /* Compute FROM and store the value in the rtx we got.  */

  push_temp_slots ();
  result = store_expr (from, to_rtx, 0, nontemporal);
  preserve_temp_slots (result);
  pop_temp_slots ();
  return;
}

/* Emits nontemporal store insn that moves FROM to TO.  Returns true if this
   succeeded, false otherwise.  */

bool
emit_storent_insn (rtx to, rtx from)
{
  struct expand_operand ops[2];
  machine_mode mode = GET_MODE (to);
  enum insn_code code = optab_handler (storent_optab, mode);

  if (code == CODE_FOR_nothing)
    return false;

  create_fixed_operand (&ops[0], to);
  create_input_operand (&ops[1], from, mode);
  return maybe_expand_insn (code, 2, ops);
}

/* Generate code for computing expression EXP,
   and storing the value into TARGET.

   If the mode is BLKmode then we may return TARGET itself.
   It turns out that in BLKmode it doesn't cause a problem.
   because C has no operators that could combine two different
   assignments into the same BLKmode object with different values
   with no sequence point.  Will other languages need this to
   be more thorough?

   If CALL_PARAM_P is nonzero, this is a store into a call param on the
   stack, and block moves may need to be treated specially.

   If NONTEMPORAL is true, try using a nontemporal store instruction.  */

rtx
store_expr (tree exp, rtx target, int call_param_p, bool nontemporal)
{
  rtx temp;
  rtx alt_rtl = NULL_RTX;
  location_t loc = curr_insn_location ();

  if (VOID_TYPE_P (TREE_TYPE (exp)))
    {
      /* C++ can generate ?: expressions with a throw expression in one
         branch and an rvalue in the other. Here, we resolve attempts to
         store the throw expression's nonexistent result.  */
      gcc_assert (!call_param_p);
      expand_expr (exp, const0_rtx, VOIDmode, EXPAND_NORMAL);
      return NULL_RTX;
    }
  if (TREE_CODE (exp) == COMPOUND_EXPR)
    {
      /* Perform first part of compound expression, then assign from second
         part.  */
      expand_expr (TREE_OPERAND (exp, 0), const0_rtx, VOIDmode,
                   call_param_p ? EXPAND_STACK_PARM : EXPAND_NORMAL);
      return store_expr (TREE_OPERAND (exp, 1), target, call_param_p,
                         nontemporal);
    }
  else if (TREE_CODE (exp) == COND_EXPR && GET_MODE (target) == BLKmode)
    {
      /* For conditional expression, get safe form of the target.  Then
         test the condition, doing the appropriate assignment on either
         side.  This avoids the creation of unnecessary temporaries.
         For non-BLKmode, it is more efficient not to do this.  */

      rtx_code_label *lab1 = gen_label_rtx (), *lab2 = gen_label_rtx ();

      do_pending_stack_adjust ();
      NO_DEFER_POP;
      jumpifnot (TREE_OPERAND (exp, 0), lab1, -1);
      store_expr (TREE_OPERAND (exp, 1), target, call_param_p,
                  nontemporal);
      emit_jump_insn (gen_jump (lab2));
      emit_barrier ();
      emit_label (lab1);
      store_expr (TREE_OPERAND (exp, 2), target, call_param_p,
                  nontemporal);
      emit_label (lab2);
      OK_DEFER_POP;

      return NULL_RTX;
    }
  else if (GET_CODE (target) == SUBREG && SUBREG_PROMOTED_VAR_P (target))
    /* If this is a scalar in a register that is stored in a wider mode
       than the declared mode, compute the result into its declared mode
       and then convert to the wider mode.  Our value is the computed
       expression.  */
    {
      rtx inner_target = 0;

      /* We can do the conversion inside EXP, which will often result
         in some optimizations.  Do the conversion in two steps: first
         change the signedness, if needed, then the extend.  But don't
         do this if the type of EXP is a subtype of something else
         since then the conversion might involve more than just
         converting modes.  */
      if (INTEGRAL_TYPE_P (TREE_TYPE (exp))
          && TREE_TYPE (TREE_TYPE (exp)) == 0
          && GET_MODE_PRECISION (GET_MODE (target))
             == TYPE_PRECISION (TREE_TYPE (exp)))
        {
          if (!SUBREG_CHECK_PROMOTED_SIGN (target,
                                          TYPE_UNSIGNED (TREE_TYPE (exp))))
            {
              /* Some types, e.g. Fortran's logical*4, won't have a signed
                 version, so use the mode instead.  */
              tree ntype
                = (signed_or_unsigned_type_for
                   (SUBREG_PROMOTED_SIGN (target), TREE_TYPE (exp)));
              if (ntype == NULL)
                ntype = lang_hooks.types.type_for_mode
                  (TYPE_MODE (TREE_TYPE (exp)),
                   SUBREG_PROMOTED_SIGN (target));

              exp = fold_convert_loc (loc, ntype, exp);
            }

          exp = fold_convert_loc (loc, lang_hooks.types.type_for_mode
                                  (GET_MODE (SUBREG_REG (target)),
                                   SUBREG_PROMOTED_SIGN (target)),
                                  exp);

          inner_target = SUBREG_REG (target);
        }

      temp = expand_expr (exp, inner_target, VOIDmode,
                          call_param_p ? EXPAND_STACK_PARM : EXPAND_NORMAL);

      /* If TEMP is a VOIDmode constant, use convert_modes to make
         sure that we properly convert it.  */
      if (CONSTANT_P (temp) && GET_MODE (temp) == VOIDmode)
        {
          temp = convert_modes (GET_MODE (target), TYPE_MODE (TREE_TYPE (exp)),
                                temp, SUBREG_PROMOTED_SIGN (target));
          temp = convert_modes (GET_MODE (SUBREG_REG (target)),
                                GET_MODE (target), temp,
                                SUBREG_PROMOTED_SIGN (target));
        }

      convert_move (SUBREG_REG (target), temp,
                    SUBREG_PROMOTED_SIGN (target));

      return NULL_RTX;
    }
  else if ((TREE_CODE (exp) == STRING_CST
            || (TREE_CODE (exp) == MEM_REF
                && TREE_CODE (TREE_OPERAND (exp, 0)) == ADDR_EXPR
                && TREE_CODE (TREE_OPERAND (TREE_OPERAND (exp, 0), 0))
                   == STRING_CST
                && integer_zerop (TREE_OPERAND (exp, 1))))
           && !nontemporal && !call_param_p
           && MEM_P (target))
    {
      /* Optimize initialization of an array with a STRING_CST.  */
      HOST_WIDE_INT exp_len, str_copy_len;
      rtx dest_mem;
      tree str = TREE_CODE (exp) == STRING_CST
                 ? exp : TREE_OPERAND (TREE_OPERAND (exp, 0), 0);

      exp_len = int_expr_size (exp);
      if (exp_len <= 0)
        goto normal_expr;

      if (TREE_STRING_LENGTH (str) <= 0)
        goto normal_expr;

      str_copy_len = strlen (TREE_STRING_POINTER (str));
      if (str_copy_len < TREE_STRING_LENGTH (str) - 1)
        goto normal_expr;

      str_copy_len = TREE_STRING_LENGTH (str);
      if ((STORE_MAX_PIECES & (STORE_MAX_PIECES - 1)) == 0
          && TREE_STRING_POINTER (str)[TREE_STRING_LENGTH (str) - 1] == '\0')
        {
          str_copy_len += STORE_MAX_PIECES - 1;
          str_copy_len &= ~(STORE_MAX_PIECES - 1);
        }
      str_copy_len = MIN (str_copy_len, exp_len);
      if (!can_store_by_pieces (str_copy_len, builtin_strncpy_read_str,
                                CONST_CAST (char *, TREE_STRING_POINTER (str)),
                                MEM_ALIGN (target), false))
        goto normal_expr;

      dest_mem = target;

      dest_mem = store_by_pieces (dest_mem,
                                  str_copy_len, builtin_strncpy_read_str,
                                  CONST_CAST (char *,
                                              TREE_STRING_POINTER (str)),
                                  MEM_ALIGN (target), false,
                                  exp_len > str_copy_len ? 1 : 0);
      if (exp_len > str_copy_len)
        clear_storage (adjust_address (dest_mem, BLKmode, 0),
                       GEN_INT (exp_len - str_copy_len),
                       BLOCK_OP_NORMAL);
      return NULL_RTX;
    }
  else
    {
      rtx tmp_target;

  normal_expr:
      /* If we want to use a nontemporal store, force the value to
         register first.  */
      tmp_target = nontemporal ? NULL_RTX : target;
      temp = expand_expr_real (exp, tmp_target, GET_MODE (target),
                               (call_param_p
                                ? EXPAND_STACK_PARM : EXPAND_NORMAL),
                               &alt_rtl, false);
    }

  /* If TEMP is a VOIDmode constant and the mode of the type of EXP is not
     the same as that of TARGET, adjust the constant.  This is needed, for
     example, in case it is a CONST_DOUBLE or CONST_WIDE_INT and we want 
     only a word-sized value.  */
  if (CONSTANT_P (temp) && GET_MODE (temp) == VOIDmode
      && TREE_CODE (exp) != ERROR_MARK
      && GET_MODE (target) != TYPE_MODE (TREE_TYPE (exp)))
    temp = convert_modes (GET_MODE (target), TYPE_MODE (TREE_TYPE (exp)),
                          temp, TYPE_UNSIGNED (TREE_TYPE (exp)));

  /* If value was not generated in the target, store it there.
     Convert the value to TARGET's type first if necessary and emit the
     pending incrementations that have been queued when expanding EXP.
     Note that we cannot emit the whole queue blindly because this will
     effectively disable the POST_INC optimization later.

     If TEMP and TARGET compare equal according to rtx_equal_p, but
     one or both of them are volatile memory refs, we have to distinguish
     two cases:
     - expand_expr has used TARGET.  In this case, we must not generate
       another copy.  This can be detected by TARGET being equal according
       to == .
     - expand_expr has not used TARGET - that means that the source just
       happens to have the same RTX form.  Since temp will have been created
       by expand_expr, it will compare unequal according to == .
       We must generate a copy in this case, to reach the correct number
       of volatile memory references.  */

  if ((! rtx_equal_p (temp, target)
       || (temp != target && (side_effects_p (temp)
                              || side_effects_p (target))))
      && TREE_CODE (exp) != ERROR_MARK
      /* If store_expr stores a DECL whose DECL_RTL(exp) == TARGET,
         but TARGET is not valid memory reference, TEMP will differ
         from TARGET although it is really the same location.  */
      && !(alt_rtl
           && rtx_equal_p (alt_rtl, target)
           && !side_effects_p (alt_rtl)
           && !side_effects_p (target))
      /* If there's nothing to copy, don't bother.  Don't call
         expr_size unless necessary, because some front-ends (C++)
         expr_size-hook must not be given objects that are not
         supposed to be bit-copied or bit-initialized.  */
      && expr_size (exp) != const0_rtx)
    {
      if (GET_MODE (temp) != GET_MODE (target) && GET_MODE (temp) != VOIDmode)
        {
          if (GET_MODE (target) == BLKmode)
            {
              /* Handle calls that return BLKmode values in registers.  */
              if (REG_P (temp) && TREE_CODE (exp) == CALL_EXPR)
                copy_blkmode_from_reg (target, temp, TREE_TYPE (exp));
              else
                store_bit_field (target,
                                 INTVAL (expr_size (exp)) * BITS_PER_UNIT,
                                 0, 0, 0, GET_MODE (temp), temp);
            }
          else
            convert_move (target, temp, TYPE_UNSIGNED (TREE_TYPE (exp)));
        }

      else if (GET_MODE (temp) == BLKmode && TREE_CODE (exp) == STRING_CST)
        {
          /* Handle copying a string constant into an array.  The string
             constant may be shorter than the array.  So copy just the string's
             actual length, and clear the rest.  First get the size of the data
             type of the string, which is actually the size of the target.  */
          rtx size = expr_size (exp);

          if (CONST_INT_P (size)
              && INTVAL (size) < TREE_STRING_LENGTH (exp))
            emit_block_move (target, temp, size,
                             (call_param_p
                              ? BLOCK_OP_CALL_PARM : BLOCK_OP_NORMAL));
          else
            {
              machine_mode pointer_mode
                = targetm.addr_space.pointer_mode (MEM_ADDR_SPACE (target));
              machine_mode address_mode = get_address_mode (target);

              /* Compute the size of the data to copy from the string.  */
              tree copy_size
                = size_binop_loc (loc, MIN_EXPR,
                                  make_tree (sizetype, size),
                                  size_int (TREE_STRING_LENGTH (exp)));
              rtx copy_size_rtx
                = expand_expr (copy_size, NULL_RTX, VOIDmode,
                               (call_param_p
                                ? EXPAND_STACK_PARM : EXPAND_NORMAL));
              rtx_code_label *label = 0;

              /* Copy that much.  */
              copy_size_rtx = convert_to_mode (pointer_mode, copy_size_rtx,
                                               TYPE_UNSIGNED (sizetype));
              emit_block_move (target, temp, copy_size_rtx,
                               (call_param_p
                                ? BLOCK_OP_CALL_PARM : BLOCK_OP_NORMAL));

              /* Figure out how much is left in TARGET that we have to clear.
                 Do all calculations in pointer_mode.  */
              if (CONST_INT_P (copy_size_rtx))
                {
                  size = plus_constant (address_mode, size,
                                        -INTVAL (copy_size_rtx));
                  target = adjust_address (target, BLKmode,
                                           INTVAL (copy_size_rtx));
                }
              else
                {
                  size = expand_binop (TYPE_MODE (sizetype), sub_optab, size,
                                       copy_size_rtx, NULL_RTX, 0,
                                       OPTAB_LIB_WIDEN);

                  if (GET_MODE (copy_size_rtx) != address_mode)
                    copy_size_rtx = convert_to_mode (address_mode,
                                                     copy_size_rtx,
                                                     TYPE_UNSIGNED (sizetype));

                  target = offset_address (target, copy_size_rtx,
                                           highest_pow2_factor (copy_size));
                  label = gen_label_rtx ();
                  emit_cmp_and_jump_insns (size, const0_rtx, LT, NULL_RTX,
                                           GET_MODE (size), 0, label);
                }

              if (size != const0_rtx)
                clear_storage (target, size, BLOCK_OP_NORMAL);

              if (label)
                emit_label (label);
            }
        }
      /* Handle calls that return values in multiple non-contiguous locations.
         The Irix 6 ABI has examples of this.  */
      else if (GET_CODE (target) == PARALLEL)
        {
          if (GET_CODE (temp) == PARALLEL)
            emit_group_move (target, temp);
          else
            emit_group_load (target, temp, TREE_TYPE (exp),
                             int_size_in_bytes (TREE_TYPE (exp)));
        }
      else if (GET_CODE (temp) == PARALLEL)
        emit_group_store (target, temp, TREE_TYPE (exp),
                          int_size_in_bytes (TREE_TYPE (exp)));
      else if (GET_MODE (temp) == BLKmode)
        emit_block_move (target, temp, expr_size (exp),
                         (call_param_p
                          ? BLOCK_OP_CALL_PARM : BLOCK_OP_NORMAL));
      /* If we emit a nontemporal store, there is nothing else to do.  */
      else if (nontemporal && emit_storent_insn (target, temp))
        ;
      else
        {
          temp = force_operand (temp, target);
          if (temp != target)
            emit_move_insn (target, temp);
        }
    }

  return NULL_RTX;
}
\f
/* Return true if field F of structure TYPE is a flexible array.  */

static bool
flexible_array_member_p (const_tree f, const_tree type)
{
  const_tree tf;

  tf = TREE_TYPE (f);
  return (DECL_CHAIN (f) == NULL
          && TREE_CODE (tf) == ARRAY_TYPE
          && TYPE_DOMAIN (tf)
          && TYPE_MIN_VALUE (TYPE_DOMAIN (tf))
          && integer_zerop (TYPE_MIN_VALUE (TYPE_DOMAIN (tf)))
          && !TYPE_MAX_VALUE (TYPE_DOMAIN (tf))
          && int_size_in_bytes (type) >= 0);
}

/* If FOR_CTOR_P, return the number of top-level elements that a constructor
   must have in order for it to completely initialize a value of type TYPE.
   Return -1 if the number isn't known.

   If !FOR_CTOR_P, return an estimate of the number of scalars in TYPE.  */

static HOST_WIDE_INT
count_type_elements (const_tree type, bool for_ctor_p)
{
  switch (TREE_CODE (type))
    {
    case ARRAY_TYPE:
      {
        tree nelts;

        nelts = array_type_nelts (type);
        if (nelts && tree_fits_uhwi_p (nelts))
          {
            unsigned HOST_WIDE_INT n;

            n = tree_to_uhwi (nelts) + 1;
            if (n == 0 || for_ctor_p)
              return n;
            else
              return n * count_type_elements (TREE_TYPE (type), false);
          }
        return for_ctor_p ? -1 : 1;
      }

    case RECORD_TYPE:
      {
        unsigned HOST_WIDE_INT n;
        tree f;

        n = 0;
        for (f = TYPE_FIELDS (type); f ; f = DECL_CHAIN (f))
          if (TREE_CODE (f) == FIELD_DECL)
            {
              if (!for_ctor_p)
                n += count_type_elements (TREE_TYPE (f), false);
              else if (!flexible_array_member_p (f, type))
                /* Don't count flexible arrays, which are not supposed
                   to be initialized.  */
                n += 1;
            }

        return n;
      }

    case UNION_TYPE:
    case QUAL_UNION_TYPE:
      {
        tree f;
        HOST_WIDE_INT n, m;

        gcc_assert (!for_ctor_p);
        /* Estimate the number of scalars in each field and pick the
           maximum.  Other estimates would do instead; the idea is simply
           to make sure that the estimate is not sensitive to the ordering
           of the fields.  */
        n = 1;
        for (f = TYPE_FIELDS (type); f ; f = DECL_CHAIN (f))
          if (TREE_CODE (f) == FIELD_DECL)
            {
              m = count_type_elements (TREE_TYPE (f), false);
              /* If the field doesn't span the whole union, add an extra
                 scalar for the rest.  */
              if (simple_cst_equal (TYPE_SIZE (TREE_TYPE (f)),
                                    TYPE_SIZE (type)) != 1)
                m++;
              if (n < m)
                n = m;
            }
        return n;
      }

    case COMPLEX_TYPE:
      return 2;

    case VECTOR_TYPE:
      return TYPE_VECTOR_SUBPARTS (type);

    case INTEGER_TYPE:
    case REAL_TYPE:
    case FIXED_POINT_TYPE:
    case ENUMERAL_TYPE:
    case BOOLEAN_TYPE:
    case POINTER_TYPE:
    case OFFSET_TYPE:
    case REFERENCE_TYPE:
    case NULLPTR_TYPE:
      return 1;

    case ERROR_MARK:
      return 0;

    case VOID_TYPE:
    case METHOD_TYPE:
    case FUNCTION_TYPE:
    case LANG_TYPE:
    default:
      gcc_unreachable ();
    }
}

/* Helper for categorize_ctor_elements.  Identical interface.  */

static bool
categorize_ctor_elements_1 (const_tree ctor, HOST_WIDE_INT *p_nz_elts,
                            HOST_WIDE_INT *p_init_elts, bool *p_complete)
{
  unsigned HOST_WIDE_INT idx;
  HOST_WIDE_INT nz_elts, init_elts, num_fields;
  tree value, purpose, elt_type;

  /* Whether CTOR is a valid constant initializer, in accordance with what
     initializer_constant_valid_p does.  If inferred from the constructor
     elements, true until proven otherwise.  */
  bool const_from_elts_p = constructor_static_from_elts_p (ctor);
  bool const_p = const_from_elts_p ? true : TREE_STATIC (ctor);

  nz_elts = 0;
  init_elts = 0;
  num_fields = 0;
  elt_type = NULL_TREE;

  FOR_EACH_CONSTRUCTOR_ELT (CONSTRUCTOR_ELTS (ctor), idx, purpose, value)
    {
      HOST_WIDE_INT mult = 1;

      if (purpose && TREE_CODE (purpose) == RANGE_EXPR)
        {
          tree lo_index = TREE_OPERAND (purpose, 0);
          tree hi_index = TREE_OPERAND (purpose, 1);

          if (tree_fits_uhwi_p (lo_index) && tree_fits_uhwi_p (hi_index))
            mult = (tree_to_uhwi (hi_index)
                    - tree_to_uhwi (lo_index) + 1);
        }
      num_fields += mult;
      elt_type = TREE_TYPE (value);

      switch (TREE_CODE (value))
        {
        case CONSTRUCTOR:
          {
            HOST_WIDE_INT nz = 0, ic = 0;

            bool const_elt_p = categorize_ctor_elements_1 (value, &nz, &ic,
                                                           p_complete);

            nz_elts += mult * nz;
            init_elts += mult * ic;

            if (const_from_elts_p && const_p)
              const_p = const_elt_p;
          }
          break;

        case INTEGER_CST:
        case REAL_CST:
        case FIXED_CST:
          if (!initializer_zerop (value))
            nz_elts += mult;
          init_elts += mult;
          break;

        case STRING_CST:
          nz_elts += mult * TREE_STRING_LENGTH (value);
          init_elts += mult * TREE_STRING_LENGTH (value);
          break;

        case COMPLEX_CST:
          if (!initializer_zerop (TREE_REALPART (value)))
            nz_elts += mult;
          if (!initializer_zerop (TREE_IMAGPART (value)))
            nz_elts += mult;
          init_elts += mult;
          break;

        case VECTOR_CST:
          {
            unsigned i;
            for (i = 0; i < VECTOR_CST_NELTS (value); ++i)
              {
                tree v = VECTOR_CST_ELT (value, i);
                if (!initializer_zerop (v))
                  nz_elts += mult;
                init_elts += mult;
              }
          }
          break;

        default:
          {
            HOST_WIDE_INT tc = count_type_elements (elt_type, false);
            nz_elts += mult * tc;
            init_elts += mult * tc;

            if (const_from_elts_p && const_p)
              const_p = initializer_constant_valid_p (value, elt_type)
                        != NULL_TREE;
          }
          break;
        }
    }

  if (*p_complete && !complete_ctor_at_level_p (TREE_TYPE (ctor),
                                                num_fields, elt_type))
    *p_complete = false;

  *p_nz_elts += nz_elts;
  *p_init_elts += init_elts;

  return const_p;
}

/* Examine CTOR to discover:
   * how many scalar fields are set to nonzero values,
     and place it in *P_NZ_ELTS;
   * how many scalar fields in total are in CTOR,
     and place it in *P_ELT_COUNT.
   * whether the constructor is complete -- in the sense that every
     meaningful byte is explicitly given a value --
     and place it in *P_COMPLETE.

   Return whether or not CTOR is a valid static constant initializer, the same
   as "initializer_constant_valid_p (CTOR, TREE_TYPE (CTOR)) != 0".  */

bool
categorize_ctor_elements (const_tree ctor, HOST_WIDE_INT *p_nz_elts,
                          HOST_WIDE_INT *p_init_elts, bool *p_complete)
{
  *p_nz_elts = 0;
  *p_init_elts = 0;
  *p_complete = true;

  return categorize_ctor_elements_1 (ctor, p_nz_elts, p_init_elts, p_complete);
}

/* TYPE is initialized by a constructor with NUM_ELTS elements, the last
   of which had type LAST_TYPE.  Each element was itself a complete
   initializer, in the sense that every meaningful byte was explicitly
   given a value.  Return true if the same is true for the constructor
   as a whole.  */

bool
complete_ctor_at_level_p (const_tree type, HOST_WIDE_INT num_elts,
                          const_tree last_type)
{
  if (TREE_CODE (type) == UNION_TYPE
      || TREE_CODE (type) == QUAL_UNION_TYPE)
    {
      if (num_elts == 0)
        return false;

      gcc_assert (num_elts == 1 && last_type);

      /* ??? We could look at each element of the union, and find the
         largest element.  Which would avoid comparing the size of the
         initialized element against any tail padding in the union.
         Doesn't seem worth the effort...  */
      return simple_cst_equal (TYPE_SIZE (type), TYPE_SIZE (last_type)) == 1;
    }

  return count_type_elements (type, true) == num_elts;
}

/* Return 1 if EXP contains mostly (3/4)  zeros.  */

static int
mostly_zeros_p (const_tree exp)
{
  if (TREE_CODE (exp) == CONSTRUCTOR)
    {
      HOST_WIDE_INT nz_elts, init_elts;
      bool complete_p;

      categorize_ctor_elements (exp, &nz_elts, &init_elts, &complete_p);
      return !complete_p || nz_elts < init_elts / 4;
    }

  return initializer_zerop (exp);
}

/* Return 1 if EXP contains all zeros.  */

static int
all_zeros_p (const_tree exp)
{
  if (TREE_CODE (exp) == CONSTRUCTOR)
    {
      HOST_WIDE_INT nz_elts, init_elts;
      bool complete_p;

      categorize_ctor_elements (exp, &nz_elts, &init_elts, &complete_p);
      return nz_elts == 0;
    }

  return initializer_zerop (exp);
}
\f
/* Helper function for store_constructor.
   TARGET, BITSIZE, BITPOS, MODE, EXP are as for store_field.
   CLEARED is as for store_constructor.
   ALIAS_SET is the alias set to use for any stores.

   This provides a recursive shortcut back to store_constructor when it isn't
   necessary to go through store_field.  This is so that we can pass through
   the cleared field to let store_constructor know that we may not have to
   clear a substructure if the outer structure has already been cleared.  */

static void
store_constructor_field (rtx target, unsigned HOST_WIDE_INT bitsize,
                         HOST_WIDE_INT bitpos, machine_mode mode,
                         tree exp, int cleared, alias_set_type alias_set)
{
  if (TREE_CODE (exp) == CONSTRUCTOR
      /* We can only call store_constructor recursively if the size and
         bit position are on a byte boundary.  */
      && bitpos % BITS_PER_UNIT == 0
      && (bitsize > 0 && bitsize % BITS_PER_UNIT == 0)
      /* If we have a nonzero bitpos for a register target, then we just
         let store_field do the bitfield handling.  This is unlikely to
         generate unnecessary clear instructions anyways.  */
      && (bitpos == 0 || MEM_P (target)))
    {
      if (MEM_P (target))
        target
          = adjust_address (target,
                            GET_MODE (target) == BLKmode
                            || 0 != (bitpos
                                     % GET_MODE_ALIGNMENT (GET_MODE (target)))
                            ? BLKmode : VOIDmode, bitpos / BITS_PER_UNIT);


      /* Update the alias set, if required.  */
      if (MEM_P (target) && ! MEM_KEEP_ALIAS_SET_P (target)
          && MEM_ALIAS_SET (target) != 0)
        {
          target = copy_rtx (target);
          set_mem_alias_set (target, alias_set);
        }

      store_constructor (exp, target, cleared, bitsize / BITS_PER_UNIT);
    }
  else
    store_field (target, bitsize, bitpos, 0, 0, mode, exp, alias_set, false);
}


/* Returns the number of FIELD_DECLs in TYPE.  */

static int
fields_length (const_tree type)
{
  tree t = TYPE_FIELDS (type);
  int count = 0;

  for (; t; t = DECL_CHAIN (t))
    if (TREE_CODE (t) == FIELD_DECL)
      ++count;

  return count;
}


/* Store the value of constructor EXP into the rtx TARGET.
   TARGET is either a REG or a MEM; we know it cannot conflict, since
   safe_from_p has been called.
   CLEARED is true if TARGET is known to have been zero'd.
   SIZE is the number of bytes of TARGET we are allowed to modify: this
   may not be the same as the size of EXP if we are assigning to a field
   which has been packed to exclude padding bits.  */

static void
store_constructor (tree exp, rtx target, int cleared, HOST_WIDE_INT size)
{
  tree type = TREE_TYPE (exp);
#ifdef WORD_REGISTER_OPERATIONS
  HOST_WIDE_INT exp_size = int_size_in_bytes (type);
#endif

  switch (TREE_CODE (type))
    {
    case RECORD_TYPE:
    case UNION_TYPE:
    case QUAL_UNION_TYPE:
      {
        unsigned HOST_WIDE_INT idx;
        tree field, value;

        /* If size is zero or the target is already cleared, do nothing.  */
        if (size == 0 || cleared)
          cleared = 1;
        /* We either clear the aggregate or indicate the value is dead.  */
        else if ((TREE_CODE (type) == UNION_TYPE
                  || TREE_CODE (type) == QUAL_UNION_TYPE)
                 && ! CONSTRUCTOR_ELTS (exp))
          /* If the constructor is empty, clear the union.  */
          {
            clear_storage (target, expr_size (exp), BLOCK_OP_NORMAL);
            cleared = 1;
          }

        /* If we are building a static constructor into a register,
           set the initial value as zero so we can fold the value into
           a constant.  But if more than one register is involved,
           this probably loses.  */
        else if (REG_P (target) && TREE_STATIC (exp)
                 && GET_MODE_SIZE (GET_MODE (target)) <= UNITS_PER_WORD)
          {
            emit_move_insn (target, CONST0_RTX (GET_MODE (target)));
            cleared = 1;
          }

        /* If the constructor has fewer fields than the structure or
           if we are initializing the structure to mostly zeros, clear
           the whole structure first.  Don't do this if TARGET is a
           register whose mode size isn't equal to SIZE since
           clear_storage can't handle this case.  */
        else if (size > 0
                 && (((int)vec_safe_length (CONSTRUCTOR_ELTS (exp))
                      != fields_length (type))
                     || mostly_zeros_p (exp))
                 && (!REG_P (target)
                     || ((HOST_WIDE_INT) GET_MODE_SIZE (GET_MODE (target))
                         == size)))
          {
            clear_storage (target, GEN_INT (size), BLOCK_OP_NORMAL);
            cleared = 1;
          }

        if (REG_P (target) && !cleared)
          emit_clobber (target);

        /* Store each element of the constructor into the
           corresponding field of TARGET.  */
        FOR_EACH_CONSTRUCTOR_ELT (CONSTRUCTOR_ELTS (exp), idx, field, value)
          {
            machine_mode mode;
            HOST_WIDE_INT bitsize;
            HOST_WIDE_INT bitpos = 0;
            tree offset;
            rtx to_rtx = target;

            /* Just ignore missing fields.  We cleared the whole
               structure, above, if any fields are missing.  */
            if (field == 0)
              continue;

            if (cleared && initializer_zerop (value))
              continue;

            if (tree_fits_uhwi_p (DECL_SIZE (field)))
              bitsize = tree_to_uhwi (DECL_SIZE (field));
            else
              bitsize = -1;

            mode = DECL_MODE (field);
            if (DECL_BIT_FIELD (field))
              mode = VOIDmode;

            offset = DECL_FIELD_OFFSET (field);
            if (tree_fits_shwi_p (offset)
                && tree_fits_shwi_p (bit_position (field)))
              {
                bitpos = int_bit_position (field);
                offset = 0;
              }
            else
              bitpos = tree_to_shwi (DECL_FIELD_BIT_OFFSET (field));

            if (offset)
              {
                machine_mode address_mode;
                rtx offset_rtx;

                offset
                  = SUBSTITUTE_PLACEHOLDER_IN_EXPR (offset,
                                                    make_tree (TREE_TYPE (exp),
                                                               target));

                offset_rtx = expand_normal (offset);
                gcc_assert (MEM_P (to_rtx));

                address_mode = get_address_mode (to_rtx);
                if (GET_MODE (offset_rtx) != address_mode)
                  offset_rtx = convert_to_mode (address_mode, offset_rtx, 0);

                to_rtx = offset_address (to_rtx, offset_rtx,
                                         highest_pow2_factor (offset));
              }

#ifdef WORD_REGISTER_OPERATIONS
            /* If this initializes a field that is smaller than a
               word, at the start of a word, try to widen it to a full
               word.  This special case allows us to output C++ member
               function initializations in a form that the optimizers
               can understand.  */
            if (REG_P (target)
                && bitsize < BITS_PER_WORD
                && bitpos % BITS_PER_WORD == 0
                && GET_MODE_CLASS (mode) == MODE_INT
                && TREE_CODE (value) == INTEGER_CST
                && exp_size >= 0
                && bitpos + BITS_PER_WORD <= exp_size * BITS_PER_UNIT)
              {
                tree type = TREE_TYPE (value);

                if (TYPE_PRECISION (type) < BITS_PER_WORD)
                  {
                    type = lang_hooks.types.type_for_mode
                      (word_mode, TYPE_UNSIGNED (type));
                    value = fold_convert (type, value);
                  }

                if (BYTES_BIG_ENDIAN)
                  value
                   = fold_build2 (LSHIFT_EXPR, type, value,
                                   build_int_cst (type,
                                                  BITS_PER_WORD - bitsize));
                bitsize = BITS_PER_WORD;
                mode = word_mode;
              }
#endif

            if (MEM_P (to_rtx) && !MEM_KEEP_ALIAS_SET_P (to_rtx)
                && DECL_NONADDRESSABLE_P (field))
              {
                to_rtx = copy_rtx (to_rtx);
                MEM_KEEP_ALIAS_SET_P (to_rtx) = 1;
              }

            store_constructor_field (to_rtx, bitsize, bitpos, mode,
                                     value, cleared,
                                     get_alias_set (TREE_TYPE (field)));
          }
        break;
      }
    case ARRAY_TYPE:
      {
        tree value, index;
        unsigned HOST_WIDE_INT i;
        int need_to_clear;
        tree domain;
        tree elttype = TREE_TYPE (type);
        int const_bounds_p;
        HOST_WIDE_INT minelt = 0;
        HOST_WIDE_INT maxelt = 0;

        domain = TYPE_DOMAIN (type);
        const_bounds_p = (TYPE_MIN_VALUE (domain)
                          && TYPE_MAX_VALUE (domain)
                          && tree_fits_shwi_p (TYPE_MIN_VALUE (domain))
                          && tree_fits_shwi_p (TYPE_MAX_VALUE (domain)));

        /* If we have constant bounds for the range of the type, get them.  */
        if (const_bounds_p)
          {
            minelt = tree_to_shwi (TYPE_MIN_VALUE (domain));
            maxelt = tree_to_shwi (TYPE_MAX_VALUE (domain));
          }

        /* If the constructor has fewer elements than the array, clear
           the whole array first.  Similarly if this is static
           constructor of a non-BLKmode object.  */
        if (cleared)
          need_to_clear = 0;
        else if (REG_P (target) && TREE_STATIC (exp))
          need_to_clear = 1;
        else
          {
            unsigned HOST_WIDE_INT idx;
            tree index, value;
            HOST_WIDE_INT count = 0, zero_count = 0;
            need_to_clear = ! const_bounds_p;

            /* This loop is a more accurate version of the loop in
               mostly_zeros_p (it handles RANGE_EXPR in an index).  It
               is also needed to check for missing elements.  */
            FOR_EACH_CONSTRUCTOR_ELT (CONSTRUCTOR_ELTS (exp), idx, index, value)
              {
                HOST_WIDE_INT this_node_count;

                if (need_to_clear)
                  break;

                if (index != NULL_TREE && TREE_CODE (index) == RANGE_EXPR)
                  {
                    tree lo_index = TREE_OPERAND (index, 0);
                    tree hi_index = TREE_OPERAND (index, 1);

                    if (! tree_fits_uhwi_p (lo_index)
                        || ! tree_fits_uhwi_p (hi_index))
                      {
                        need_to_clear = 1;
                        break;
                      }

                    this_node_count = (tree_to_uhwi (hi_index)
                                       - tree_to_uhwi (lo_index) + 1);
                  }
                else
                  this_node_count = 1;

                count += this_node_count;
                if (mostly_zeros_p (value))
                  zero_count += this_node_count;
              }

            /* Clear the entire array first if there are any missing
               elements, or if the incidence of zero elements is >=
               75%.  */
            if (! need_to_clear
                && (count < maxelt - minelt + 1
                    || 4 * zero_count >= 3 * count))
              need_to_clear = 1;
          }

        if (need_to_clear && size > 0)
          {
            if (REG_P (target))
              emit_move_insn (target,  CONST0_RTX (GET_MODE (target)));
            else
              clear_storage (target, GEN_INT (size), BLOCK_OP_NORMAL);
            cleared = 1;
          }

        if (!cleared && REG_P (target))
          /* Inform later passes that the old value is dead.  */
          emit_clobber (target);

        /* Store each element of the constructor into the
           corresponding element of TARGET, determined by counting the
           elements.  */
        FOR_EACH_CONSTRUCTOR_ELT (CONSTRUCTOR_ELTS (exp), i, index, value)
          {
            machine_mode mode;
            HOST_WIDE_INT bitsize;
            HOST_WIDE_INT bitpos;
            rtx xtarget = target;

            if (cleared && initializer_zerop (value))
              continue;

            mode = TYPE_MODE (elttype);
            if (mode == BLKmode)
              bitsize = (tree_fits_uhwi_p (TYPE_SIZE (elttype))
                         ? tree_to_uhwi (TYPE_SIZE (elttype))
                         : -1);
            else
              bitsize = GET_MODE_BITSIZE (mode);

            if (index != NULL_TREE && TREE_CODE (index) == RANGE_EXPR)
              {
                tree lo_index = TREE_OPERAND (index, 0);
                tree hi_index = TREE_OPERAND (index, 1);
                rtx index_r, pos_rtx;
                HOST_WIDE_INT lo, hi, count;
                tree position;

                /* If the range is constant and "small", unroll the loop.  */
                if (const_bounds_p
                    && tree_fits_shwi_p (lo_index)
                    && tree_fits_shwi_p (hi_index)
                    && (lo = tree_to_shwi (lo_index),
                        hi = tree_to_shwi (hi_index),
                        count = hi - lo + 1,
                        (!MEM_P (target)
                         || count <= 2
                         || (tree_fits_uhwi_p (TYPE_SIZE (elttype))
                             && (tree_to_uhwi (TYPE_SIZE (elttype)) * count
                                 <= 40 * 8)))))
                  {
                    lo -= minelt;  hi -= minelt;
                    for (; lo <= hi; lo++)
                      {
                        bitpos = lo * tree_to_shwi (TYPE_SIZE (elttype));

                        if (MEM_P (target)
                            && !MEM_KEEP_ALIAS_SET_P (target)
                            && TREE_CODE (type) == ARRAY_TYPE
                            && TYPE_NONALIASED_COMPONENT (type))
                          {
                            target = copy_rtx (target);
                            MEM_KEEP_ALIAS_SET_P (target) = 1;
                          }

                        store_constructor_field
                          (target, bitsize, bitpos, mode, value, cleared,
                           get_alias_set (elttype));
                      }
                  }
                else
                  {
                    rtx_code_label *loop_start = gen_label_rtx ();
                    rtx_code_label *loop_end = gen_label_rtx ();
                    tree exit_cond;

                    expand_normal (hi_index);

                    index = build_decl (EXPR_LOCATION (exp),
                                        VAR_DECL, NULL_TREE, domain);
                    index_r = gen_reg_rtx (promote_decl_mode (index, NULL));
                    SET_DECL_RTL (index, index_r);
                    store_expr (lo_index, index_r, 0, false);

                    /* Build the head of the loop.  */
                    do_pending_stack_adjust ();
                    emit_label (loop_start);

                    /* Assign value to element index.  */
                    position =
                      fold_convert (ssizetype,
                                    fold_build2 (MINUS_EXPR,
                                                 TREE_TYPE (index),
                                                 index,
                                                 TYPE_MIN_VALUE (domain)));

                    position =
                        size_binop (MULT_EXPR, position,
                                    fold_convert (ssizetype,
                                                  TYPE_SIZE_UNIT (elttype)));

                    pos_rtx = expand_normal (position);
                    xtarget = offset_address (target, pos_rtx,
                                              highest_pow2_factor (position));
                    xtarget = adjust_address (xtarget, mode, 0);
                    if (TREE_CODE (value) == CONSTRUCTOR)
                      store_constructor (value, xtarget, cleared,
                                         bitsize / BITS_PER_UNIT);
                    else
                      store_expr (value, xtarget, 0, false);

                    /* Generate a conditional jump to exit the loop.  */
                    exit_cond = build2 (LT_EXPR, integer_type_node,
                                        index, hi_index);
                    jumpif (exit_cond, loop_end, -1);

                    /* Update the loop counter, and jump to the head of
                       the loop.  */
                    expand_assignment (index,
                                       build2 (PLUS_EXPR, TREE_TYPE (index),
                                               index, integer_one_node),
                                       false);

                    emit_jump (loop_start);

                    /* Build the end of the loop.  */
                    emit_label (loop_end);
                  }
              }
            else if ((index != 0 && ! tree_fits_shwi_p (index))
                     || ! tree_fits_uhwi_p (TYPE_SIZE (elttype)))
              {
                tree position;

                if (index == 0)
                  index = ssize_int (1);

                if (minelt)
                  index = fold_convert (ssizetype,
                                        fold_build2 (MINUS_EXPR,
                                                     TREE_TYPE (index),
                                                     index,
                                                     TYPE_MIN_VALUE (domain)));

                position =
                  size_binop (MULT_EXPR, index,
                              fold_convert (ssizetype,
                                            TYPE_SIZE_UNIT (elttype)));
                xtarget = offset_address (target,
                                          expand_normal (position),
                                          highest_pow2_factor (position));
                xtarget = adjust_address (xtarget, mode, 0);
                store_expr (value, xtarget, 0, false);
              }
            else
              {
                if (index != 0)
                  bitpos = ((tree_to_shwi (index) - minelt)
                            * tree_to_uhwi (TYPE_SIZE (elttype)));
                else
                  bitpos = (i * tree_to_uhwi (TYPE_SIZE (elttype)));

                if (MEM_P (target) && !MEM_KEEP_ALIAS_SET_P (target)
                    && TREE_CODE (type) == ARRAY_TYPE
                    && TYPE_NONALIASED_COMPONENT (type))
                  {
                    target = copy_rtx (target);
                    MEM_KEEP_ALIAS_SET_P (target) = 1;
                  }
                store_constructor_field (target, bitsize, bitpos, mode, value,
                                         cleared, get_alias_set (elttype));
              }
          }
        break;
      }

    case VECTOR_TYPE:
      {
        unsigned HOST_WIDE_INT idx;
        constructor_elt *ce;
        int i;
        int need_to_clear;
        int icode = CODE_FOR_nothing;
        tree elttype = TREE_TYPE (type);
        int elt_size = tree_to_uhwi (TYPE_SIZE (elttype));
        machine_mode eltmode = TYPE_MODE (elttype);
        HOST_WIDE_INT bitsize;
        HOST_WIDE_INT bitpos;
        rtvec vector = NULL;
        unsigned n_elts;
        alias_set_type alias;

        gcc_assert (eltmode != BLKmode);

        n_elts = TYPE_VECTOR_SUBPARTS (type);
        if (REG_P (target) && VECTOR_MODE_P (GET_MODE (target)))
          {
            machine_mode mode = GET_MODE (target);

            icode = (int) optab_handler (vec_init_optab, mode);
            /* Don't use vec_init<mode> if some elements have VECTOR_TYPE.  */
            if (icode != CODE_FOR_nothing)
              {
                tree value;

                FOR_EACH_CONSTRUCTOR_VALUE (CONSTRUCTOR_ELTS (exp), idx, value)
                  if (TREE_CODE (TREE_TYPE (value)) == VECTOR_TYPE)
                    {
                      icode = CODE_FOR_nothing;
                      break;
                    }
              }
            if (icode != CODE_FOR_nothing)
              {
                unsigned int i;

                vector = rtvec_alloc (n_elts);
                for (i = 0; i < n_elts; i++)
                  RTVEC_ELT (vector, i) = CONST0_RTX (GET_MODE_INNER (mode));
              }
          }

        /* If the constructor has fewer elements than the vector,
           clear the whole array first.  Similarly if this is static
           constructor of a non-BLKmode object.  */
        if (cleared)
          need_to_clear = 0;
        else if (REG_P (target) && TREE_STATIC (exp))
          need_to_clear = 1;
        else
          {
            unsigned HOST_WIDE_INT count = 0, zero_count = 0;
            tree value;

            FOR_EACH_CONSTRUCTOR_VALUE (CONSTRUCTOR_ELTS (exp), idx, value)
              {
                int n_elts_here = tree_to_uhwi
                  (int_const_binop (TRUNC_DIV_EXPR,
                                    TYPE_SIZE (TREE_TYPE (value)),
                                    TYPE_SIZE (elttype)));

                count += n_elts_here;
                if (mostly_zeros_p (value))
                  zero_count += n_elts_here;
              }

            /* Clear the entire vector first if there are any missing elements,
               or if the incidence of zero elements is >= 75%.  */
            need_to_clear = (count < n_elts || 4 * zero_count >= 3 * count);
          }

        if (need_to_clear && size > 0 && !vector)
          {
            if (REG_P (target))
              emit_move_insn (target, CONST0_RTX (GET_MODE (target)));
            else
              clear_storage (target, GEN_INT (size), BLOCK_OP_NORMAL);
            cleared = 1;
          }

        /* Inform later passes that the old value is dead.  */
        if (!cleared && !vector && REG_P (target))
          emit_move_insn (target, CONST0_RTX (GET_MODE (target)));

        if (MEM_P (target))
          alias = MEM_ALIAS_SET (target);
        else
          alias = get_alias_set (elttype);

        /* Store each element of the constructor into the corresponding
           element of TARGET, determined by counting the elements.  */
        for (idx = 0, i = 0;
             vec_safe_iterate (CONSTRUCTOR_ELTS (exp), idx, &ce);
             idx++, i += bitsize / elt_size)
          {
            HOST_WIDE_INT eltpos;
            tree value = ce->value;

            bitsize = tree_to_uhwi (TYPE_SIZE (TREE_TYPE (value)));
            if (cleared && initializer_zerop (value))
              continue;

            if (ce->index)
              eltpos = tree_to_uhwi (ce->index);
            else
              eltpos = i;

            if (vector)
              {
                /* vec_init<mode> should not be used if there are VECTOR_TYPE
                   elements.  */
                gcc_assert (TREE_CODE (TREE_TYPE (value)) != VECTOR_TYPE);
                RTVEC_ELT (vector, eltpos)
                  = expand_normal (value);
              }
            else
              {
                machine_mode value_mode =
                  TREE_CODE (TREE_TYPE (value)) == VECTOR_TYPE
                  ? TYPE_MODE (TREE_TYPE (value))
                  : eltmode;
                bitpos = eltpos * elt_size;
                store_constructor_field (target, bitsize, bitpos, value_mode,
                                         value, cleared, alias);
              }
          }

        if (vector)
          emit_insn (GEN_FCN (icode)
                     (target,
                      gen_rtx_PARALLEL (GET_MODE (target), vector)));
        break;
      }

    default:
      gcc_unreachable ();
    }
}

/* Store the value of EXP (an expression tree)
   into a subfield of TARGET which has mode MODE and occupies
   BITSIZE bits, starting BITPOS bits from the start of TARGET.
   If MODE is VOIDmode, it means that we are storing into a bit-field.

   BITREGION_START is bitpos of the first bitfield in this region.
   BITREGION_END is the bitpos of the ending bitfield in this region.
   These two fields are 0, if the C++ memory model does not apply,
   or we are not interested in keeping track of bitfield regions.

   Always return const0_rtx unless we have something particular to
   return.

   ALIAS_SET is the alias set for the destination.  This value will
   (in general) be different from that for TARGET, since TARGET is a
   reference to the containing structure.

   If NONTEMPORAL is true, try generating a nontemporal store.  */

static rtx
store_field (rtx target, HOST_WIDE_INT bitsize, HOST_WIDE_INT bitpos,
             unsigned HOST_WIDE_INT bitregion_start,
             unsigned HOST_WIDE_INT bitregion_end,
             machine_mode mode, tree exp,
             alias_set_type alias_set, bool nontemporal)
{
  if (TREE_CODE (exp) == ERROR_MARK)
    return const0_rtx;

  /* If we have nothing to store, do nothing unless the expression has
     side-effects.  */
  if (bitsize == 0)
    return expand_expr (exp, const0_rtx, VOIDmode, EXPAND_NORMAL);

  if (GET_CODE (target) == CONCAT)
    {
      /* We're storing into a struct containing a single __complex.  */

      gcc_assert (!bitpos);
      return store_expr (exp, target, 0, nontemporal);
    }

  /* If the structure is in a register or if the component
     is a bit field, we cannot use addressing to access it.
     Use bit-field techniques or SUBREG to store in it.  */

  if (mode == VOIDmode
      || (mode != BLKmode && ! direct_store[(int) mode]
          && GET_MODE_CLASS (mode) != MODE_COMPLEX_INT
          && GET_MODE_CLASS (mode) != MODE_COMPLEX_FLOAT)
      || REG_P (target)
      || GET_CODE (target) == SUBREG
      /* If the field isn't aligned enough to store as an ordinary memref,
         store it as a bit field.  */
      || (mode != BLKmode
          && ((((MEM_ALIGN (target) < GET_MODE_ALIGNMENT (mode))
                || bitpos % GET_MODE_ALIGNMENT (mode))
               && SLOW_UNALIGNED_ACCESS (mode, MEM_ALIGN (target)))
              || (bitpos % BITS_PER_UNIT != 0)))
      || (bitsize >= 0 && mode != BLKmode
          && GET_MODE_BITSIZE (mode) > bitsize)
      /* If the RHS and field are a constant size and the size of the
         RHS isn't the same size as the bitfield, we must use bitfield
         operations.  */
      || (bitsize >= 0
          && TREE_CODE (TYPE_SIZE (TREE_TYPE (exp))) == INTEGER_CST
          && compare_tree_int (TYPE_SIZE (TREE_TYPE (exp)), bitsize) != 0)
      /* If we are expanding a MEM_REF of a non-BLKmode non-addressable
         decl we must use bitfield operations.  */
      || (bitsize >= 0
          && TREE_CODE (exp) == MEM_REF
          && TREE_CODE (TREE_OPERAND (exp, 0)) == ADDR_EXPR
          && DECL_P (TREE_OPERAND (TREE_OPERAND (exp, 0), 0))
          && !TREE_ADDRESSABLE (TREE_OPERAND (TREE_OPERAND (exp, 0),0 ))
          && DECL_MODE (TREE_OPERAND (TREE_OPERAND (exp, 0), 0)) != BLKmode))
    {
      rtx temp;
      gimple nop_def;

      /* If EXP is a NOP_EXPR of precision less than its mode, then that
         implies a mask operation.  If the precision is the same size as
         the field we're storing into, that mask is redundant.  This is
         particularly common with bit field assignments generated by the
         C front end.  */
      nop_def = get_def_for_expr (exp, NOP_EXPR);
      if (nop_def)
        {
          tree type = TREE_TYPE (exp);
          if (INTEGRAL_TYPE_P (type)
              && TYPE_PRECISION (type) < GET_MODE_BITSIZE (TYPE_MODE (type))
              && bitsize == TYPE_PRECISION (type))
            {
              tree op = gimple_assign_rhs1 (nop_def);
              type = TREE_TYPE (op);
              if (INTEGRAL_TYPE_P (type) && TYPE_PRECISION (type) >= bitsize)
                exp = op;
            }
        }

      temp = expand_normal (exp);

      /* If BITSIZE is narrower than the size of the type of EXP
         we will be narrowing TEMP.  Normally, what's wanted are the
         low-order bits.  However, if EXP's type is a record and this is
         big-endian machine, we want the upper BITSIZE bits.  */
      if (BYTES_BIG_ENDIAN && GET_MODE_CLASS (GET_MODE (temp)) == MODE_INT
          && bitsize < (HOST_WIDE_INT) GET_MODE_BITSIZE (GET_MODE (temp))
          && TREE_CODE (TREE_TYPE (exp)) == RECORD_TYPE)
        temp = expand_shift (RSHIFT_EXPR, GET_MODE (temp), temp,
                             GET_MODE_BITSIZE (GET_MODE (temp)) - bitsize,
                             NULL_RTX, 1);

      /* Unless MODE is VOIDmode or BLKmode, convert TEMP to MODE.  */
      if (mode != VOIDmode && mode != BLKmode
          && mode != TYPE_MODE (TREE_TYPE (exp)))
        temp = convert_modes (mode, TYPE_MODE (TREE_TYPE (exp)), temp, 1);

      /* If the modes of TEMP and TARGET are both BLKmode, both
         must be in memory and BITPOS must be aligned on a byte
         boundary.  If so, we simply do a block copy.  Likewise
         for a BLKmode-like TARGET.  */
      if (GET_MODE (temp) == BLKmode
          && (GET_MODE (target) == BLKmode
              || (MEM_P (target)
                  && GET_MODE_CLASS (GET_MODE (target)) == MODE_INT
                  && (bitpos % BITS_PER_UNIT) == 0
                  && (bitsize % BITS_PER_UNIT) == 0)))
        {
          gcc_assert (MEM_P (target) && MEM_P (temp)
                      && (bitpos % BITS_PER_UNIT) == 0);

          target = adjust_address (target, VOIDmode, bitpos / BITS_PER_UNIT);
          emit_block_move (target, temp,
                           GEN_INT ((bitsize + BITS_PER_UNIT - 1)
                                    / BITS_PER_UNIT),
                           BLOCK_OP_NORMAL);

          return const0_rtx;
        }

      /* Handle calls that return values in multiple non-contiguous locations.
         The Irix 6 ABI has examples of this.  */
      if (GET_CODE (temp) == PARALLEL)
        {
          HOST_WIDE_INT size = int_size_in_bytes (TREE_TYPE (exp));
          rtx temp_target;
          if (mode == BLKmode || mode == VOIDmode)
            mode = smallest_mode_for_size (size * BITS_PER_UNIT, MODE_INT);
          temp_target = gen_reg_rtx (mode);
          emit_group_store (temp_target, temp, TREE_TYPE (exp), size);
          temp = temp_target;
        }
      else if (mode == BLKmode)
        {
          /* Handle calls that return BLKmode values in registers.  */
          if (REG_P (temp) && TREE_CODE (exp) == CALL_EXPR)
            {
              rtx temp_target = gen_reg_rtx (GET_MODE (temp));
              copy_blkmode_from_reg (temp_target, temp, TREE_TYPE (exp));
              temp = temp_target;
            }
          else
            {
              HOST_WIDE_INT size = int_size_in_bytes (TREE_TYPE (exp));
              rtx temp_target;
              mode = smallest_mode_for_size (size * BITS_PER_UNIT, MODE_INT);
              temp_target = gen_reg_rtx (mode);
              temp_target
                = extract_bit_field (temp, size * BITS_PER_UNIT, 0, 1,
                                     temp_target, mode, mode);
              temp = temp_target;
            }
        }

      /* Store the value in the bitfield.  */
      store_bit_field (target, bitsize, bitpos,
                       bitregion_start, bitregion_end,
                       mode, temp);

      return const0_rtx;
    }
  else
    {
      /* Now build a reference to just the desired component.  */
      rtx to_rtx = adjust_address (target, mode, bitpos / BITS_PER_UNIT);

      if (to_rtx == target)
        to_rtx = copy_rtx (to_rtx);

      if (!MEM_KEEP_ALIAS_SET_P (to_rtx) && MEM_ALIAS_SET (to_rtx) != 0)
        set_mem_alias_set (to_rtx, alias_set);

      return store_expr (exp, to_rtx, 0, nontemporal);
    }
}
\f
/* Given an expression EXP that may be a COMPONENT_REF, a BIT_FIELD_REF,
   an ARRAY_REF, or an ARRAY_RANGE_REF, look for nested operations of these
   codes and find the ultimate containing object, which we return.

   We set *PBITSIZE to the size in bits that we want, *PBITPOS to the
   bit position, and *PUNSIGNEDP to the signedness of the field.
   If the position of the field is variable, we store a tree
   giving the variable offset (in units) in *POFFSET.
   This offset is in addition to the bit position.
   If the position is not variable, we store 0 in *POFFSET.

   If any of the extraction expressions is volatile,
   we store 1 in *PVOLATILEP.  Otherwise we don't change that.

   If the field is a non-BLKmode bit-field, *PMODE is set to VOIDmode.
   Otherwise, it is a mode that can be used to access the field.

   If the field describes a variable-sized object, *PMODE is set to
   BLKmode and *PBITSIZE is set to -1.  An access cannot be made in
   this case, but the address of the object can be found.

   If KEEP_ALIGNING is true and the target is STRICT_ALIGNMENT, we don't
   look through nodes that serve as markers of a greater alignment than
   the one that can be deduced from the expression.  These nodes make it
   possible for front-ends to prevent temporaries from being created by
   the middle-end on alignment considerations.  For that purpose, the
   normal operating mode at high-level is to always pass FALSE so that
   the ultimate containing object is really returned; moreover, the
   associated predicate handled_component_p will always return TRUE
   on these nodes, thus indicating that they are essentially handled
   by get_inner_reference.  TRUE should only be passed when the caller
   is scanning the expression in order to build another representation
   and specifically knows how to handle these nodes; as such, this is
   the normal operating mode in the RTL expanders.  */

tree
get_inner_reference (tree exp, HOST_WIDE_INT *pbitsize,
                     HOST_WIDE_INT *pbitpos, tree *poffset,
                     machine_mode *pmode, int *punsignedp,
                     int *pvolatilep, bool keep_aligning)
{
  tree size_tree = 0;
  machine_mode mode = VOIDmode;
  bool blkmode_bitfield = false;
  tree offset = size_zero_node;
  offset_int bit_offset = 0;

  /* First get the mode, signedness, and size.  We do this from just the
     outermost expression.  */
  *pbitsize = -1;
  if (TREE_CODE (exp) == COMPONENT_REF)
    {
      tree field = TREE_OPERAND (exp, 1);
      size_tree = DECL_SIZE (field);
      if (flag_strict_volatile_bitfields > 0
          && TREE_THIS_VOLATILE (exp)
          && DECL_BIT_FIELD_TYPE (field)
          && DECL_MODE (field) != BLKmode)
        /* Volatile bitfields should be accessed in the mode of the
             field's type, not the mode computed based on the bit
             size.  */
        mode = TYPE_MODE (DECL_BIT_FIELD_TYPE (field));
      else if (!DECL_BIT_FIELD (field))
        mode = DECL_MODE (field);
      else if (DECL_MODE (field) == BLKmode)
        blkmode_bitfield = true;

      *punsignedp = DECL_UNSIGNED (field);
    }
  else if (TREE_CODE (exp) == BIT_FIELD_REF)
    {
      size_tree = TREE_OPERAND (exp, 1);
      *punsignedp = (! INTEGRAL_TYPE_P (TREE_TYPE (exp))
                     || TYPE_UNSIGNED (TREE_TYPE (exp)));

      /* For vector types, with the correct size of access, use the mode of
         inner type.  */
      if (TREE_CODE (TREE_TYPE (TREE_OPERAND (exp, 0))) == VECTOR_TYPE
          && TREE_TYPE (exp) == TREE_TYPE (TREE_TYPE (TREE_OPERAND (exp, 0)))
          && tree_int_cst_equal (size_tree, TYPE_SIZE (TREE_TYPE (exp))))
        mode = TYPE_MODE (TREE_TYPE (exp));
    }
  else
    {
      mode = TYPE_MODE (TREE_TYPE (exp));
      *punsignedp = TYPE_UNSIGNED (TREE_TYPE (exp));

      if (mode == BLKmode)
        size_tree = TYPE_SIZE (TREE_TYPE (exp));
      else
        *pbitsize = GET_MODE_BITSIZE (mode);
    }

  if (size_tree != 0)
    {
      if (! tree_fits_uhwi_p (size_tree))
        mode = BLKmode, *pbitsize = -1;
      else
        *pbitsize = tree_to_uhwi (size_tree);
    }

  /* Compute cumulative bit-offset for nested component-refs and array-refs,
     and find the ultimate containing object.  */
  while (1)
    {
      switch (TREE_CODE (exp))
        {
        case BIT_FIELD_REF:
          bit_offset += wi::to_offset (TREE_OPERAND (exp, 2));
          break;

        case COMPONENT_REF:
          {
            tree field = TREE_OPERAND (exp, 1);
            tree this_offset = component_ref_field_offset (exp);

            /* If this field hasn't been filled in yet, don't go past it.
               This should only happen when folding expressions made during
               type construction.  */
            if (this_offset == 0)
              break;

            offset = size_binop (PLUS_EXPR, offset, this_offset);
            bit_offset += wi::to_offset (DECL_FIELD_BIT_OFFSET (field));

            /* ??? Right now we don't do anything with DECL_OFFSET_ALIGN.  */
          }
          break;

        case ARRAY_REF:
        case ARRAY_RANGE_REF:
          {
            tree index = TREE_OPERAND (exp, 1);
            tree low_bound = array_ref_low_bound (exp);
            tree unit_size = array_ref_element_size (exp);

            /* We assume all arrays have sizes that are a multiple of a byte.
               First subtract the lower bound, if any, in the type of the
               index, then convert to sizetype and multiply by the size of
               the array element.  */
            if (! integer_zerop (low_bound))
              index = fold_build2 (MINUS_EXPR, TREE_TYPE (index),
                                   index, low_bound);

            offset = size_binop (PLUS_EXPR, offset,
                                 size_binop (MULT_EXPR,
                                             fold_convert (sizetype, index),
                                             unit_size));
          }
          break;

        case REALPART_EXPR:
          break;

        case IMAGPART_EXPR:
          bit_offset += *pbitsize;
          break;

        case VIEW_CONVERT_EXPR:
          if (keep_aligning && STRICT_ALIGNMENT
              && (TYPE_ALIGN (TREE_TYPE (exp))
               > TYPE_ALIGN (TREE_TYPE (TREE_OPERAND (exp, 0))))
              && (TYPE_ALIGN (TREE_TYPE (TREE_OPERAND (exp, 0)))
                  < BIGGEST_ALIGNMENT)
              && (TYPE_ALIGN_OK (TREE_TYPE (exp))
                  || TYPE_ALIGN_OK (TREE_TYPE (TREE_OPERAND (exp, 0)))))
            goto done;
          break;

        case MEM_REF:
          /* Hand back the decl for MEM[&decl, off].  */
          if (TREE_CODE (TREE_OPERAND (exp, 0)) == ADDR_EXPR)
            {
              tree off = TREE_OPERAND (exp, 1);
              if (!integer_zerop (off))
                {
                  offset_int boff, coff = mem_ref_offset (exp);
                  boff = wi::lshift (coff, LOG2_BITS_PER_UNIT);
                  bit_offset += boff;
                }
              exp = TREE_OPERAND (TREE_OPERAND (exp, 0), 0);
            }
          goto done;

        default:
          goto done;
        }

      /* If any reference in the chain is volatile, the effect is volatile.  */
      if (TREE_THIS_VOLATILE (exp))
        *pvolatilep = 1;

      exp = TREE_OPERAND (exp, 0);
    }
 done:

  /* If OFFSET is constant, see if we can return the whole thing as a
     constant bit position.  Make sure to handle overflow during
     this conversion.  */
  if (TREE_CODE (offset) == INTEGER_CST)
    {
      offset_int tem = wi::sext (wi::to_offset (offset),
                                 TYPE_PRECISION (sizetype));
      tem = wi::lshift (tem, LOG2_BITS_PER_UNIT);
      tem += bit_offset;
      if (wi::fits_shwi_p (tem))
        {
          *pbitpos = tem.to_shwi ();
          *poffset = offset = NULL_TREE;
        }
    }

  /* Otherwise, split it up.  */
  if (offset)
    {
      /* Avoid returning a negative bitpos as this may wreak havoc later.  */
      if (wi::neg_p (bit_offset))
        {
          offset_int mask = wi::mask <offset_int> (LOG2_BITS_PER_UNIT, false);
          offset_int tem = bit_offset.and_not (mask);
          /* TEM is the bitpos rounded to BITS_PER_UNIT towards -Inf.
             Subtract it to BIT_OFFSET and add it (scaled) to OFFSET.  */
          bit_offset -= tem;
          tem = wi::arshift (tem, LOG2_BITS_PER_UNIT);
          offset = size_binop (PLUS_EXPR, offset,
                               wide_int_to_tree (sizetype, tem));
        }

      *pbitpos = bit_offset.to_shwi ();
      *poffset = offset;
    }

  /* We can use BLKmode for a byte-aligned BLKmode bitfield.  */
  if (mode == VOIDmode
      && blkmode_bitfield
      && (*pbitpos % BITS_PER_UNIT) == 0
      && (*pbitsize % BITS_PER_UNIT) == 0)
    *pmode = BLKmode;
  else
    *pmode = mode;

  return exp;
}

/* Return a tree of sizetype representing the size, in bytes, of the element
   of EXP, an ARRAY_REF or an ARRAY_RANGE_REF.  */

tree
array_ref_element_size (tree exp)
{
  tree aligned_size = TREE_OPERAND (exp, 3);
  tree elmt_type = TREE_TYPE (TREE_TYPE (TREE_OPERAND (exp, 0)));
  location_t loc = EXPR_LOCATION (exp);

  /* If a size was specified in the ARRAY_REF, it's the size measured
     in alignment units of the element type.  So multiply by that value.  */
  if (aligned_size)
    {
      /* ??? tree_ssa_useless_type_conversion will eliminate casts to
         sizetype from another type of the same width and signedness.  */
      if (TREE_TYPE (aligned_size) != sizetype)
        aligned_size = fold_convert_loc (loc, sizetype, aligned_size);
      return size_binop_loc (loc, MULT_EXPR, aligned_size,
                             size_int (TYPE_ALIGN_UNIT (elmt_type)));
    }

  /* Otherwise, take the size from that of the element type.  Substitute
     any PLACEHOLDER_EXPR that we have.  */
  else
    return SUBSTITUTE_PLACEHOLDER_IN_EXPR (TYPE_SIZE_UNIT (elmt_type), exp);
}

/* Return a tree representing the lower bound of the array mentioned in
   EXP, an ARRAY_REF or an ARRAY_RANGE_REF.  */

tree
array_ref_low_bound (tree exp)
{
  tree domain_type = TYPE_DOMAIN (TREE_TYPE (TREE_OPERAND (exp, 0)));

  /* If a lower bound is specified in EXP, use it.  */
  if (TREE_OPERAND (exp, 2))
    return TREE_OPERAND (exp, 2);

  /* Otherwise, if there is a domain type and it has a lower bound, use it,
     substituting for a PLACEHOLDER_EXPR as needed.  */
  if (domain_type && TYPE_MIN_VALUE (domain_type))
    return SUBSTITUTE_PLACEHOLDER_IN_EXPR (TYPE_MIN_VALUE (domain_type), exp);

  /* Otherwise, return a zero of the appropriate type.  */
  return build_int_cst (TREE_TYPE (TREE_OPERAND (exp, 1)), 0);
}

/* Returns true if REF is an array reference to an array at the end of
   a structure.  If this is the case, the array may be allocated larger
   than its upper bound implies.  */

bool
array_at_struct_end_p (tree ref)
{
  if (TREE_CODE (ref) != ARRAY_REF
      && TREE_CODE (ref) != ARRAY_RANGE_REF)
    return false;

  while (handled_component_p (ref))
    {
      /* If the reference chain contains a component reference to a
         non-union type and there follows another field the reference
         is not at the end of a structure.  */
      if (TREE_CODE (ref) == COMPONENT_REF
          && TREE_CODE (TREE_TYPE (TREE_OPERAND (ref, 0))) == RECORD_TYPE)
        {
          tree nextf = DECL_CHAIN (TREE_OPERAND (ref, 1));
          while (nextf && TREE_CODE (nextf) != FIELD_DECL)
            nextf = DECL_CHAIN (nextf);
          if (nextf)
            return false;
        }

      ref = TREE_OPERAND (ref, 0);
    }

  /* If the reference is based on a declared entity, the size of the array
     is constrained by its given domain.  */
  if (DECL_P (ref))
    return false;

  return true;
}

/* Return a tree representing the upper bound of the array mentioned in
   EXP, an ARRAY_REF or an ARRAY_RANGE_REF.  */

tree
array_ref_up_bound (tree exp)
{
  tree domain_type = TYPE_DOMAIN (TREE_TYPE (TREE_OPERAND (exp, 0)));

  /* If there is a domain type and it has an upper bound, use it, substituting
     for a PLACEHOLDER_EXPR as needed.  */
  if (domain_type && TYPE_MAX_VALUE (domain_type))
    return SUBSTITUTE_PLACEHOLDER_IN_EXPR (TYPE_MAX_VALUE (domain_type), exp);

  /* Otherwise fail.  */
  return NULL_TREE;
}

/* Return a tree representing the offset, in bytes, of the field referenced
   by EXP.  This does not include any offset in DECL_FIELD_BIT_OFFSET.  */

tree
component_ref_field_offset (tree exp)
{
  tree aligned_offset = TREE_OPERAND (exp, 2);
  tree field = TREE_OPERAND (exp, 1);
  location_t loc = EXPR_LOCATION (exp);

  /* If an offset was specified in the COMPONENT_REF, it's the offset measured
     in units of DECL_OFFSET_ALIGN / BITS_PER_UNIT.  So multiply by that
     value.  */
  if (aligned_offset)
    {
      /* ??? tree_ssa_useless_type_conversion will eliminate casts to
         sizetype from another type of the same width and signedness.  */
      if (TREE_TYPE (aligned_offset) != sizetype)
        aligned_offset = fold_convert_loc (loc, sizetype, aligned_offset);
      return size_binop_loc (loc, MULT_EXPR, aligned_offset,
                             size_int (DECL_OFFSET_ALIGN (field)
                                       / BITS_PER_UNIT));
    }

  /* Otherwise, take the offset from that of the field.  Substitute
     any PLACEHOLDER_EXPR that we have.  */
  else
    return SUBSTITUTE_PLACEHOLDER_IN_EXPR (DECL_FIELD_OFFSET (field), exp);
}

/* Alignment in bits the TARGET of an assignment may be assumed to have.  */

static unsigned HOST_WIDE_INT
target_align (const_tree target)
{
  /* We might have a chain of nested references with intermediate misaligning
     bitfields components, so need to recurse to find out.  */

  unsigned HOST_WIDE_INT this_align, outer_align;

  switch (TREE_CODE (target))
    {
    case BIT_FIELD_REF:
      return 1;

    case COMPONENT_REF:
      this_align = DECL_ALIGN (TREE_OPERAND (target, 1));
      outer_align = target_align (TREE_OPERAND (target, 0));
      return MIN (this_align, outer_align);

    case ARRAY_REF:
    case ARRAY_RANGE_REF:
      this_align = TYPE_ALIGN (TREE_TYPE (target));
      outer_align = target_align (TREE_OPERAND (target, 0));
      return MIN (this_align, outer_align);

    CASE_CONVERT:
    case NON_LVALUE_EXPR:
    case VIEW_CONVERT_EXPR:
      this_align = TYPE_ALIGN (TREE_TYPE (target));
      outer_align = target_align (TREE_OPERAND (target, 0));
      return MAX (this_align, outer_align);

    default:
      return TYPE_ALIGN (TREE_TYPE (target));
    }
}

\f
/* Given an rtx VALUE that may contain additions and multiplications, return
   an equivalent value that just refers to a register, memory, or constant.
   This is done by generating instructions to perform the arithmetic and
   returning a pseudo-register containing the value.

   The returned value may be a REG, SUBREG, MEM or constant.  */

rtx
force_operand (rtx value, rtx target)
{
  rtx op1, op2;
  /* Use subtarget as the target for operand 0 of a binary operation.  */
  rtx subtarget = get_subtarget (target);
  enum rtx_code code = GET_CODE (value);

  /* Check for subreg applied to an expression produced by loop optimizer.  */
  if (code == SUBREG
      && !REG_P (SUBREG_REG (value))
      && !MEM_P (SUBREG_REG (value)))
    {
      value
        = simplify_gen_subreg (GET_MODE (value),
                               force_reg (GET_MODE (SUBREG_REG (value)),
                                          force_operand (SUBREG_REG (value),
                                                         NULL_RTX)),
                               GET_MODE (SUBREG_REG (value)),
                               SUBREG_BYTE (value));
      code = GET_CODE (value);
    }

  /* Check for a PIC address load.  */
  if ((code == PLUS || code == MINUS)
      && XEXP (value, 0) == pic_offset_table_rtx
      && (GET_CODE (XEXP (value, 1)) == SYMBOL_REF
          || GET_CODE (XEXP (value, 1)) == LABEL_REF
          || GET_CODE (XEXP (value, 1)) == CONST))
    {
      if (!subtarget)
        subtarget = gen_reg_rtx (GET_MODE (value));
      emit_move_insn (subtarget, value);
      return subtarget;
    }

  if (ARITHMETIC_P (value))
    {
      op2 = XEXP (value, 1);
      if (!CONSTANT_P (op2) && !(REG_P (op2) && op2 != subtarget))
        subtarget = 0;
      if (code == MINUS && CONST_INT_P (op2))
        {
          code = PLUS;
          op2 = negate_rtx (GET_MODE (value), op2);
        }

      /* Check for an addition with OP2 a constant integer and our first
         operand a PLUS of a virtual register and something else.  In that
         case, we want to emit the sum of the virtual register and the
         constant first and then add the other value.  This allows virtual
         register instantiation to simply modify the constant rather than
         creating another one around this addition.  */
      if (code == PLUS && CONST_INT_P (op2)
          && GET_CODE (XEXP (value, 0)) == PLUS
          && REG_P (XEXP (XEXP (value, 0), 0))
          && REGNO (XEXP (XEXP (value, 0), 0)) >= FIRST_VIRTUAL_REGISTER
          && REGNO (XEXP (XEXP (value, 0), 0)) <= LAST_VIRTUAL_REGISTER)
        {
          rtx temp = expand_simple_binop (GET_MODE (value), code,
                                          XEXP (XEXP (value, 0), 0), op2,
                                          subtarget, 0, OPTAB_LIB_WIDEN);
          return expand_simple_binop (GET_MODE (value), code, temp,
                                      force_operand (XEXP (XEXP (value,
                                                                 0), 1), 0),
                                      target, 0, OPTAB_LIB_WIDEN);
        }

      op1 = force_operand (XEXP (value, 0), subtarget);
      op2 = force_operand (op2, NULL_RTX);
      switch (code)
        {
        case MULT:
          return expand_mult (GET_MODE (value), op1, op2, target, 1);
        case DIV:
          if (!INTEGRAL_MODE_P (GET_MODE (value)))
            return expand_simple_binop (GET_MODE (value), code, op1, op2,
                                        target, 1, OPTAB_LIB_WIDEN);
          else
            return expand_divmod (0,
                                  FLOAT_MODE_P (GET_MODE (value))
                                  ? RDIV_EXPR : TRUNC_DIV_EXPR,
                                  GET_MODE (value), op1, op2, target, 0);
        case MOD:
          return expand_divmod (1, TRUNC_MOD_EXPR, GET_MODE (value), op1, op2,
                                target, 0);
        case UDIV:
          return expand_divmod (0, TRUNC_DIV_EXPR, GET_MODE (value), op1, op2,
                                target, 1);
        case UMOD:
          return expand_divmod (1, TRUNC_MOD_EXPR, GET_MODE (value), op1, op2,
                                target, 1);
        case ASHIFTRT:
          return expand_simple_binop (GET_MODE (value), code, op1, op2,
                                      target, 0, OPTAB_LIB_WIDEN);
        default:
          return expand_simple_binop (GET_MODE (value), code, op1, op2,
                                      target, 1, OPTAB_LIB_WIDEN);
        }
    }
  if (UNARY_P (value))
    {
      if (!target)
        target = gen_reg_rtx (GET_MODE (value));
      op1 = force_operand (XEXP (value, 0), NULL_RTX);
      switch (code)
        {
        case ZERO_EXTEND:
        case SIGN_EXTEND:
        case TRUNCATE:
        case FLOAT_EXTEND:
        case FLOAT_TRUNCATE:
          convert_move (target, op1, code == ZERO_EXTEND);
          return target;

        case FIX:
        case UNSIGNED_FIX:
          expand_fix (target, op1, code == UNSIGNED_FIX);
          return target;

        case FLOAT:
        case UNSIGNED_FLOAT:
          expand_float (target, op1, code == UNSIGNED_FLOAT);
          return target;

        default:
          return expand_simple_unop (GET_MODE (value), code, op1, target, 0);
        }
    }

#ifdef INSN_SCHEDULING
  /* On machines that have insn scheduling, we want all memory reference to be
     explicit, so we need to deal with such paradoxical SUBREGs.  */
  if (paradoxical_subreg_p (value) && MEM_P (SUBREG_REG (value)))
    value
      = simplify_gen_subreg (GET_MODE (value),
                             force_reg (GET_MODE (SUBREG_REG (value)),
                                        force_operand (SUBREG_REG (value),
                                                       NULL_RTX)),
                             GET_MODE (SUBREG_REG (value)),
                             SUBREG_BYTE (value));
#endif

  return value;
}
\f
/* Subroutine of expand_expr: return nonzero iff there is no way that
   EXP can reference X, which is being modified.  TOP_P is nonzero if this
   call is going to be used to determine whether we need a temporary
   for EXP, as opposed to a recursive call to this function.

   It is always safe for this routine to return zero since it merely
   searches for optimization opportunities.  */

int
safe_from_p (const_rtx x, tree exp, int top_p)
{
  rtx exp_rtl = 0;
  int i, nops;

  if (x == 0
      /* If EXP has varying size, we MUST use a target since we currently
         have no way of allocating temporaries of variable size
         (except for arrays that have TYPE_ARRAY_MAX_SIZE set).
         So we assume here that something at a higher level has prevented a
         clash.  This is somewhat bogus, but the best we can do.  Only
         do this when X is BLKmode and when we are at the top level.  */
      || (top_p && TREE_TYPE (exp) != 0 && COMPLETE_TYPE_P (TREE_TYPE (exp))
          && TREE_CODE (TYPE_SIZE (TREE_TYPE (exp))) != INTEGER_CST
          && (TREE_CODE (TREE_TYPE (exp)) != ARRAY_TYPE
              || TYPE_ARRAY_MAX_SIZE (TREE_TYPE (exp)) == NULL_TREE
              || TREE_CODE (TYPE_ARRAY_MAX_SIZE (TREE_TYPE (exp)))
              != INTEGER_CST)
          && GET_MODE (x) == BLKmode)
      /* If X is in the outgoing argument area, it is always safe.  */
      || (MEM_P (x)
          && (XEXP (x, 0) == virtual_outgoing_args_rtx
              || (GET_CODE (XEXP (x, 0)) == PLUS
                  && XEXP (XEXP (x, 0), 0) == virtual_outgoing_args_rtx))))
    return 1;

  /* If this is a subreg of a hard register, declare it unsafe, otherwise,
     find the underlying pseudo.  */
  if (GET_CODE (x) == SUBREG)
    {
      x = SUBREG_REG (x);
      if (REG_P (x) && REGNO (x) < FIRST_PSEUDO_REGISTER)
        return 0;
    }

  /* Now look at our tree code and possibly recurse.  */
  switch (TREE_CODE_CLASS (TREE_CODE (exp)))
    {
    case tcc_declaration:
      exp_rtl = DECL_RTL_IF_SET (exp);
      break;

    case tcc_constant:
      return 1;

    case tcc_exceptional:
      if (TREE_CODE (exp) == TREE_LIST)
        {
          while (1)
            {
              if (TREE_VALUE (exp) && !safe_from_p (x, TREE_VALUE (exp), 0))
                return 0;
              exp = TREE_CHAIN (exp);
              if (!exp)
                return 1;
              if (TREE_CODE (exp) != TREE_LIST)
                return safe_from_p (x, exp, 0);
            }
        }
      else if (TREE_CODE (exp) == CONSTRUCTOR)
        {
          constructor_elt *ce;
          unsigned HOST_WIDE_INT idx;

          FOR_EACH_VEC_SAFE_ELT (CONSTRUCTOR_ELTS (exp), idx, ce)
            if ((ce->index != NULL_TREE && !safe_from_p (x, ce->index, 0))
                || !safe_from_p (x, ce->value, 0))
              return 0;
          return 1;
        }
      else if (TREE_CODE (exp) == ERROR_MARK)
        return 1;       /* An already-visited SAVE_EXPR? */
      else
        return 0;

    case tcc_statement:
      /* The only case we look at here is the DECL_INITIAL inside a
         DECL_EXPR.  */
      return (TREE_CODE (exp) != DECL_EXPR
              || TREE_CODE (DECL_EXPR_DECL (exp)) != VAR_DECL
              || !DECL_INITIAL (DECL_EXPR_DECL (exp))
              || safe_from_p (x, DECL_INITIAL (DECL_EXPR_DECL (exp)), 0));

    case tcc_binary:
    case tcc_comparison:
      if (!safe_from_p (x, TREE_OPERAND (exp, 1), 0))
        return 0;
      /* Fall through.  */

    case tcc_unary:
      return safe_from_p (x, TREE_OPERAND (exp, 0), 0);

    case tcc_expression:
    case tcc_reference:
    case tcc_vl_exp:
      /* Now do code-specific tests.  EXP_RTL is set to any rtx we find in
         the expression.  If it is set, we conflict iff we are that rtx or
         both are in memory.  Otherwise, we check all operands of the
         expression recursively.  */

      switch (TREE_CODE (exp))
        {
        case ADDR_EXPR:
          /* If the operand is static or we are static, we can't conflict.
             Likewise if we don't conflict with the operand at all.  */
          if (staticp (TREE_OPERAND (exp, 0))
              || TREE_STATIC (exp)
              || safe_from_p (x, TREE_OPERAND (exp, 0), 0))
            return 1;

          /* Otherwise, the only way this can conflict is if we are taking
             the address of a DECL a that address if part of X, which is
             very rare.  */
          exp = TREE_OPERAND (exp, 0);
          if (DECL_P (exp))
            {
              if (!DECL_RTL_SET_P (exp)
                  || !MEM_P (DECL_RTL (exp)))
                return 0;
              else
                exp_rtl = XEXP (DECL_RTL (exp), 0);
            }
          break;

        case MEM_REF:
          if (MEM_P (x)
              && alias_sets_conflict_p (MEM_ALIAS_SET (x),
                                        get_alias_set (exp)))
            return 0;
          break;

        case CALL_EXPR:
          /* Assume that the call will clobber all hard registers and
             all of memory.  */
          if ((REG_P (x) && REGNO (x) < FIRST_PSEUDO_REGISTER)
              || MEM_P (x))
            return 0;
          break;

        case WITH_CLEANUP_EXPR:
        case CLEANUP_POINT_EXPR:
          /* Lowered by gimplify.c.  */
          gcc_unreachable ();

        case SAVE_EXPR:
          return safe_from_p (x, TREE_OPERAND (exp, 0), 0);

        default:
          break;
        }

      /* If we have an rtx, we do not need to scan our operands.  */
      if (exp_rtl)
        break;

      nops = TREE_OPERAND_LENGTH (exp);
      for (i = 0; i < nops; i++)
        if (TREE_OPERAND (exp, i) != 0
            && ! safe_from_p (x, TREE_OPERAND (exp, i), 0))
          return 0;

      break;

    case tcc_type:
      /* Should never get a type here.  */
      gcc_unreachable ();
    }

  /* If we have an rtl, find any enclosed object.  Then see if we conflict
     with it.  */
  if (exp_rtl)
    {
      if (GET_CODE (exp_rtl) == SUBREG)
        {
          exp_rtl = SUBREG_REG (exp_rtl);
          if (REG_P (exp_rtl)
              && REGNO (exp_rtl) < FIRST_PSEUDO_REGISTER)
            return 0;
        }

      /* If the rtl is X, then it is not safe.  Otherwise, it is unless both
         are memory and they conflict.  */
      return ! (rtx_equal_p (x, exp_rtl)
                || (MEM_P (x) && MEM_P (exp_rtl)
                    && true_dependence (exp_rtl, VOIDmode, x)));
    }

  /* If we reach here, it is safe.  */
  return 1;
}

\f
/* Return the highest power of two that EXP is known to be a multiple of.
   This is used in updating alignment of MEMs in array references.  */

unsigned HOST_WIDE_INT
highest_pow2_factor (const_tree exp)
{
  unsigned HOST_WIDE_INT ret;
  int trailing_zeros = tree_ctz (exp);
  if (trailing_zeros >= HOST_BITS_PER_WIDE_INT)
    return BIGGEST_ALIGNMENT;
  ret = (unsigned HOST_WIDE_INT) 1 << trailing_zeros;
  if (ret > BIGGEST_ALIGNMENT)
    return BIGGEST_ALIGNMENT;
  return ret;
}

/* Similar, except that the alignment requirements of TARGET are
   taken into account.  Assume it is at least as aligned as its
   type, unless it is a COMPONENT_REF in which case the layout of
   the structure gives the alignment.  */

static unsigned HOST_WIDE_INT
highest_pow2_factor_for_target (const_tree target, const_tree exp)
{
  unsigned HOST_WIDE_INT talign = target_align (target) / BITS_PER_UNIT;
  unsigned HOST_WIDE_INT factor = highest_pow2_factor (exp);

  return MAX (factor, talign);
}
\f
#ifdef HAVE_conditional_move
/* Convert the tree comparison code TCODE to the rtl one where the
   signedness is UNSIGNEDP.  */

static enum rtx_code
convert_tree_comp_to_rtx (enum tree_code tcode, int unsignedp)
{
  enum rtx_code code;
  switch (tcode)
    {
    case EQ_EXPR:
      code = EQ;
      break;
    case NE_EXPR:
      code = NE;
      break;
    case LT_EXPR:
      code = unsignedp ? LTU : LT;
      break;
    case LE_EXPR:
      code = unsignedp ? LEU : LE;
      break;
    case GT_EXPR:
      code = unsignedp ? GTU : GT;
      break;
    case GE_EXPR:
      code = unsignedp ? GEU : GE;
      break;
    case UNORDERED_EXPR:
      code = UNORDERED;
      break;
    case ORDERED_EXPR:
      code = ORDERED;
      break;
    case UNLT_EXPR:
      code = UNLT;
      break;
    case UNLE_EXPR:
      code = UNLE;
      break;
    case UNGT_EXPR:
      code = UNGT;
      break;
    case UNGE_EXPR:
      code = UNGE;
      break;
    case UNEQ_EXPR:
      code = UNEQ;
      break;
    case LTGT_EXPR:
      code = LTGT;
      break;

    default:
      gcc_unreachable ();
    }
  return code;
}
#endif

/* Subroutine of expand_expr.  Expand the two operands of a binary
   expression EXP0 and EXP1 placing the results in OP0 and OP1.
   The value may be stored in TARGET if TARGET is nonzero.  The
   MODIFIER argument is as documented by expand_expr.  */

static void
expand_operands (tree exp0, tree exp1, rtx target, rtx *op0, rtx *op1,
                 enum expand_modifier modifier)
{
  if (! safe_from_p (target, exp1, 1))
    target = 0;
  if (operand_equal_p (exp0, exp1, 0))
    {
      *op0 = expand_expr (exp0, target, VOIDmode, modifier);
      *op1 = copy_rtx (*op0);
    }
  else
    {
      /* If we need to preserve evaluation order, copy exp0 into its own
         temporary variable so that it can't be clobbered by exp1.  */
      if (flag_evaluation_order && TREE_SIDE_EFFECTS (exp1))
        exp0 = save_expr (exp0);
      *op0 = expand_expr (exp0, target, VOIDmode, modifier);
      *op1 = expand_expr (exp1, NULL_RTX, VOIDmode, modifier);
    }
}

\f
/* Return a MEM that contains constant EXP.  DEFER is as for
   output_constant_def and MODIFIER is as for expand_expr.  */

static rtx
expand_expr_constant (tree exp, int defer, enum expand_modifier modifier)
{
  rtx mem;

  mem = output_constant_def (exp, defer);
  if (modifier != EXPAND_INITIALIZER)
    mem = use_anchored_address (mem);
  return mem;
}

/* A subroutine of expand_expr_addr_expr.  Evaluate the address of EXP.
   The TARGET, TMODE and MODIFIER arguments are as for expand_expr.  */

static rtx
expand_expr_addr_expr_1 (tree exp, rtx target, machine_mode tmode,
                         enum expand_modifier modifier, addr_space_t as)
{
  rtx result, subtarget;
  tree inner, offset;
  HOST_WIDE_INT bitsize, bitpos;
  int volatilep, unsignedp;
  machine_mode mode1;

  /* If we are taking the address of a constant and are at the top level,
     we have to use output_constant_def since we can't call force_const_mem
     at top level.  */
  /* ??? This should be considered a front-end bug.  We should not be
     generating ADDR_EXPR of something that isn't an LVALUE.  The only
     exception here is STRING_CST.  */
  if (CONSTANT_CLASS_P (exp))
    {
      result = XEXP (expand_expr_constant (exp, 0, modifier), 0);
      if (modifier < EXPAND_SUM)
        result = force_operand (result, target);
      return result;
    }

  /* Everything must be something allowed by is_gimple_addressable.  */
  switch (TREE_CODE (exp))
    {
    case INDIRECT_REF:
      /* This case will happen via recursion for &a->b.  */
      return expand_expr (TREE_OPERAND (exp, 0), target, tmode, modifier);

    case MEM_REF:
      {
        tree tem = TREE_OPERAND (exp, 0);
        if (!integer_zerop (TREE_OPERAND (exp, 1)))
          tem = fold_build_pointer_plus (tem, TREE_OPERAND (exp, 1));
        return expand_expr (tem, target, tmode, modifier);
      }

    case CONST_DECL:
      /* Expand the initializer like constants above.  */
      result = XEXP (expand_expr_constant (DECL_INITIAL (exp),
                                           0, modifier), 0);
      if (modifier < EXPAND_SUM)
        result = force_operand (result, target);
      return result;

    case REALPART_EXPR:
      /* The real part of the complex number is always first, therefore
         the address is the same as the address of the parent object.  */
      offset = 0;
      bitpos = 0;
      inner = TREE_OPERAND (exp, 0);
      break;

    case IMAGPART_EXPR:
      /* The imaginary part of the complex number is always second.
         The expression is therefore always offset by the size of the
         scalar type.  */
      offset = 0;
      bitpos = GET_MODE_BITSIZE (TYPE_MODE (TREE_TYPE (exp)));
      inner = TREE_OPERAND (exp, 0);
      break;

    case COMPOUND_LITERAL_EXPR:
      /* Allow COMPOUND_LITERAL_EXPR in initializers, if e.g.
         rtl_for_decl_init is called on DECL_INITIAL with
         COMPOUNT_LITERAL_EXPRs in it, they aren't gimplified.  */
      if (modifier == EXPAND_INITIALIZER
          && COMPOUND_LITERAL_EXPR_DECL (exp))
        return expand_expr_addr_expr_1 (COMPOUND_LITERAL_EXPR_DECL (exp),
                                        target, tmode, modifier, as);
      /* FALLTHRU */
    default:
      /* If the object is a DECL, then expand it for its rtl.  Don't bypass
         expand_expr, as that can have various side effects; LABEL_DECLs for
         example, may not have their DECL_RTL set yet.  Expand the rtl of
         CONSTRUCTORs too, which should yield a memory reference for the
         constructor's contents.  Assume language specific tree nodes can
         be expanded in some interesting way.  */
      gcc_assert (TREE_CODE (exp) < LAST_AND_UNUSED_TREE_CODE);
      if (DECL_P (exp)
          || TREE_CODE (exp) == CONSTRUCTOR
          || TREE_CODE (exp) == COMPOUND_LITERAL_EXPR)
        {
          result = expand_expr (exp, target, tmode,
                                modifier == EXPAND_INITIALIZER
                                ? EXPAND_INITIALIZER : EXPAND_CONST_ADDRESS);

          /* If the DECL isn't in memory, then the DECL wasn't properly
             marked TREE_ADDRESSABLE, which will be either a front-end
             or a tree optimizer bug.  */

          if (TREE_ADDRESSABLE (exp)
              && ! MEM_P (result)
              && ! targetm.calls.allocate_stack_slots_for_args ())
            {
              error ("local frame unavailable (naked function?)");
              return result;
            }
          else
            gcc_assert (MEM_P (result));
          result = XEXP (result, 0);

          /* ??? Is this needed anymore?  */
          if (DECL_P (exp))
            TREE_USED (exp) = 1;

          if (modifier != EXPAND_INITIALIZER
              && modifier != EXPAND_CONST_ADDRESS
              && modifier != EXPAND_SUM)
            result = force_operand (result, target);
          return result;
        }

      /* Pass FALSE as the last argument to get_inner_reference although
         we are expanding to RTL.  The rationale is that we know how to
         handle "aligning nodes" here: we can just bypass them because
         they won't change the final object whose address will be returned
         (they actually exist only for that purpose).  */
      inner = get_inner_reference (exp, &bitsize, &bitpos, &offset,
                                   &mode1, &unsignedp, &volatilep, false);
      break;
    }

  /* We must have made progress.  */
  gcc_assert (inner != exp);

  subtarget = offset || bitpos ? NULL_RTX : target;
  /* For VIEW_CONVERT_EXPR, where the outer alignment is bigger than
     inner alignment, force the inner to be sufficiently aligned.  */
  if (CONSTANT_CLASS_P (inner)
      && TYPE_ALIGN (TREE_TYPE (inner)) < TYPE_ALIGN (TREE_TYPE (exp)))
    {
      inner = copy_node (inner);
      TREE_TYPE (inner) = copy_node (TREE_TYPE (inner));
      TYPE_ALIGN (TREE_TYPE (inner)) = TYPE_ALIGN (TREE_TYPE (exp));
      TYPE_USER_ALIGN (TREE_TYPE (inner)) = 1;
    }
  result = expand_expr_addr_expr_1 (inner, subtarget, tmode, modifier, as);

  if (offset)
    {
      rtx tmp;

      if (modifier != EXPAND_NORMAL)
        result = force_operand (result, NULL);
      tmp = expand_expr (offset, NULL_RTX, tmode,
                         modifier == EXPAND_INITIALIZER
                          ? EXPAND_INITIALIZER : EXPAND_NORMAL);

      /* expand_expr is allowed to return an object in a mode other
         than TMODE.  If it did, we need to convert.  */
      if (GET_MODE (tmp) != VOIDmode && tmode != GET_MODE (tmp))
        tmp = convert_modes (tmode, GET_MODE (tmp),
                             tmp, TYPE_UNSIGNED (TREE_TYPE (offset)));
      result = convert_memory_address_addr_space (tmode, result, as);
      tmp = convert_memory_address_addr_space (tmode, tmp, as);

      if (modifier == EXPAND_SUM || modifier == EXPAND_INITIALIZER)
        result = simplify_gen_binary (PLUS, tmode, result, tmp);
      else
        {
          subtarget = bitpos ? NULL_RTX : target;
          result = expand_simple_binop (tmode, PLUS, result, tmp, subtarget,
                                        1, OPTAB_LIB_WIDEN);
        }
    }

  if (bitpos)
    {
      /* Someone beforehand should have rejected taking the address
         of such an object.  */
      gcc_assert ((bitpos % BITS_PER_UNIT) == 0);

      result = convert_memory_address_addr_space (tmode, result, as);
      result = plus_constant (tmode, result, bitpos / BITS_PER_UNIT);
      if (modifier < EXPAND_SUM)
        result = force_operand (result, target);
    }

  return result;
}

/* A subroutine of expand_expr.  Evaluate EXP, which is an ADDR_EXPR.
   The TARGET, TMODE and MODIFIER arguments are as for expand_expr.  */

static rtx
expand_expr_addr_expr (tree exp, rtx target, machine_mode tmode,
                       enum expand_modifier modifier)
{
  addr_space_t as = ADDR_SPACE_GENERIC;
  machine_mode address_mode = Pmode;
  machine_mode pointer_mode = ptr_mode;
  machine_mode rmode;
  rtx result;

  /* Target mode of VOIDmode says "whatever's natural".  */
  if (tmode == VOIDmode)
    tmode = TYPE_MODE (TREE_TYPE (exp));

  if (POINTER_TYPE_P (TREE_TYPE (exp)))
    {
      as = TYPE_ADDR_SPACE (TREE_TYPE (TREE_TYPE (exp)));
      address_mode = targetm.addr_space.address_mode (as);
      pointer_mode = targetm.addr_space.pointer_mode (as);
    }

  /* We can get called with some Weird Things if the user does silliness
     like "(short) &a".  In that case, convert_memory_address won't do
     the right thing, so ignore the given target mode.  */
  if (tmode != address_mode && tmode != pointer_mode)
    tmode = address_mode;

  result = expand_expr_addr_expr_1 (TREE_OPERAND (exp, 0), target,
                                    tmode, modifier, as);

  /* Despite expand_expr claims concerning ignoring TMODE when not
     strictly convenient, stuff breaks if we don't honor it.  Note
     that combined with the above, we only do this for pointer modes.  */
  rmode = GET_MODE (result);
  if (rmode == VOIDmode)
    rmode = tmode;
  if (rmode != tmode)
    result = convert_memory_address_addr_space (tmode, result, as);

  return result;
}

/* Generate code for computing CONSTRUCTOR EXP.
   An rtx for the computed value is returned.  If AVOID_TEMP_MEM
   is TRUE, instead of creating a temporary variable in memory
   NULL is returned and the caller needs to handle it differently.  */

static rtx
expand_constructor (tree exp, rtx target, enum expand_modifier modifier,
                    bool avoid_temp_mem)
{
  tree type = TREE_TYPE (exp);
  machine_mode mode = TYPE_MODE (type);

  /* Try to avoid creating a temporary at all.  This is possible
     if all of the initializer is zero.
     FIXME: try to handle all [0..255] initializers we can handle
     with memset.  */
  if (TREE_STATIC (exp)
      && !TREE_ADDRESSABLE (exp)
      && target != 0 && mode == BLKmode
      && all_zeros_p (exp))
    {
      clear_storage (target, expr_size (exp), BLOCK_OP_NORMAL);
      return target;
    }

  /* All elts simple constants => refer to a constant in memory.  But
     if this is a non-BLKmode mode, let it store a field at a time
     since that should make a CONST_INT, CONST_WIDE_INT or
     CONST_DOUBLE when we fold.  Likewise, if we have a target we can
     use, it is best to store directly into the target unless the type
     is large enough that memcpy will be used.  If we are making an
     initializer and all operands are constant, put it in memory as
     well.

     FIXME: Avoid trying to fill vector constructors piece-meal.
     Output them with output_constant_def below unless we're sure
     they're zeros.  This should go away when vector initializers
     are treated like VECTOR_CST instead of arrays.  */
  if ((TREE_STATIC (exp)
       && ((mode == BLKmode
            && ! (target != 0 && safe_from_p (target, exp, 1)))
                  || TREE_ADDRESSABLE (exp)
                  || (tree_fits_uhwi_p (TYPE_SIZE_UNIT (type))
                      && (! MOVE_BY_PIECES_P
                                     (tree_to_uhwi (TYPE_SIZE_UNIT (type)),
                                      TYPE_ALIGN (type)))
                      && ! mostly_zeros_p (exp))))
      || ((modifier == EXPAND_INITIALIZER || modifier == EXPAND_CONST_ADDRESS)
          && TREE_CONSTANT (exp)))
    {
      rtx constructor;

      if (avoid_temp_mem)
        return NULL_RTX;

      constructor = expand_expr_constant (exp, 1, modifier);

      if (modifier != EXPAND_CONST_ADDRESS
          && modifier != EXPAND_INITIALIZER
          && modifier != EXPAND_SUM)
        constructor = validize_mem (constructor);

      return constructor;
    }

  /* Handle calls that pass values in multiple non-contiguous
     locations.  The Irix 6 ABI has examples of this.  */
  if (target == 0 || ! safe_from_p (target, exp, 1)
      || GET_CODE (target) == PARALLEL || modifier == EXPAND_STACK_PARM)
    {
      if (avoid_temp_mem)
        return NULL_RTX;

      target = assign_temp (type, TREE_ADDRESSABLE (exp), 1);
    }

  store_constructor (exp, target, 0, int_expr_size (exp));
  return target;
}


/* expand_expr: generate code for computing expression EXP.
   An rtx for the computed value is returned.  The value is never null.
   In the case of a void EXP, const0_rtx is returned.

   The value may be stored in TARGET if TARGET is nonzero.
   TARGET is just a suggestion; callers must assume that
   the rtx returned may not be the same as TARGET.

   If TARGET is CONST0_RTX, it means that the value will be ignored.

   If TMODE is not VOIDmode, it suggests generating the
   result in mode TMODE.  But this is done only when convenient.
   Otherwise, TMODE is ignored and the value generated in its natural mode.
   TMODE is just a suggestion; callers must assume that
   the rtx returned may not have mode TMODE.

   Note that TARGET may have neither TMODE nor MODE.  In that case, it
   probably will not be used.

   If MODIFIER is EXPAND_SUM then when EXP is an addition
   we can return an rtx of the form (MULT (REG ...) (CONST_INT ...))
   or a nest of (PLUS ...) and (MINUS ...) where the terms are
   products as above, or REG or MEM, or constant.
   Ordinarily in such cases we would output mul or add instructions
   and then return a pseudo reg containing the sum.

   EXPAND_INITIALIZER is much like EXPAND_SUM except that
   it also marks a label as absolutely required (it can't be dead).
   It also makes a ZERO_EXTEND or SIGN_EXTEND instead of emitting extend insns.
   This is used for outputting expressions used in initializers.

   EXPAND_CONST_ADDRESS says that it is okay to return a MEM
   with a constant address even if that address is not normally legitimate.
   EXPAND_INITIALIZER and EXPAND_SUM also have this effect.

   EXPAND_STACK_PARM is used when expanding to a TARGET on the stack for
   a call parameter.  Such targets require special care as we haven't yet
   marked TARGET so that it's safe from being trashed by libcalls.  We
   don't want to use TARGET for anything but the final result;
   Intermediate values must go elsewhere.   Additionally, calls to
   emit_block_move will be flagged with BLOCK_OP_CALL_PARM.

   If EXP is a VAR_DECL whose DECL_RTL was a MEM with an invalid
   address, and ALT_RTL is non-NULL, then *ALT_RTL is set to the
   DECL_RTL of the VAR_DECL.  *ALT_RTL is also set if EXP is a
   COMPOUND_EXPR whose second argument is such a VAR_DECL, and so on
   recursively.

   If INNER_REFERENCE_P is true, we are expanding an inner reference.
   In this case, we don't adjust a returned MEM rtx that wouldn't be
   sufficiently aligned for its mode; instead, it's up to the caller
   to deal with it afterwards.  This is used to make sure that unaligned
   base objects for which out-of-bounds accesses are supported, for
   example record types with trailing arrays, aren't realigned behind
   the back of the caller.
   The normal operating mode is to pass FALSE for this parameter.  */

rtx
expand_expr_real (tree exp, rtx target, machine_mode tmode,
                  enum expand_modifier modifier, rtx *alt_rtl,
                  bool inner_reference_p)
{
  rtx ret;

  /* Handle ERROR_MARK before anybody tries to access its type.  */
  if (TREE_CODE (exp) == ERROR_MARK
      || (TREE_CODE (TREE_TYPE (exp)) == ERROR_MARK))
    {
      ret = CONST0_RTX (tmode);
      return ret ? ret : const0_rtx;
    }

  ret = expand_expr_real_1 (exp, target, tmode, modifier, alt_rtl,
                            inner_reference_p);
  return ret;
}

/* Try to expand the conditional expression which is represented by
   TREEOP0 ? TREEOP1 : TREEOP2 using conditonal moves.  If succeseds
   return the rtl reg which repsents the result.  Otherwise return
   NULL_RTL.  */

static rtx
expand_cond_expr_using_cmove (tree treeop0 ATTRIBUTE_UNUSED,
                              tree treeop1 ATTRIBUTE_UNUSED,
                              tree treeop2 ATTRIBUTE_UNUSED)
{
#ifdef HAVE_conditional_move
  rtx insn;
  rtx op00, op01, op1, op2;
  enum rtx_code comparison_code;
  machine_mode comparison_mode;
  gimple srcstmt;
  rtx temp;
  tree type = TREE_TYPE (treeop1);
  int unsignedp = TYPE_UNSIGNED (type);
  machine_mode mode = TYPE_MODE (type);
  machine_mode orig_mode = mode;

  /* If we cannot do a conditional move on the mode, try doing it
     with the promoted mode. */
  if (!can_conditionally_move_p (mode))
    {
      mode = promote_mode (type, mode, &unsignedp);
      if (!can_conditionally_move_p (mode))
        return NULL_RTX;
      temp = assign_temp (type, 0, 0); /* Use promoted mode for temp.  */
    }
  else
    temp = assign_temp (type, 0, 1);

  start_sequence ();
  expand_operands (treeop1, treeop2,
                   temp, &op1, &op2, EXPAND_NORMAL);

  if (TREE_CODE (treeop0) == SSA_NAME
      && (srcstmt = get_def_for_expr_class (treeop0, tcc_comparison)))
    {
      tree type = TREE_TYPE (gimple_assign_rhs1 (srcstmt));
      enum tree_code cmpcode = gimple_assign_rhs_code (srcstmt);
      op00 = expand_normal (gimple_assign_rhs1 (srcstmt));
      op01 = expand_normal (gimple_assign_rhs2 (srcstmt));
      comparison_mode = TYPE_MODE (type);
      unsignedp = TYPE_UNSIGNED (type);
      comparison_code = convert_tree_comp_to_rtx (cmpcode, unsignedp);
    }
  else if (TREE_CODE_CLASS (TREE_CODE (treeop0)) == tcc_comparison)
    {
      tree type = TREE_TYPE (TREE_OPERAND (treeop0, 0));
      enum tree_code cmpcode = TREE_CODE (treeop0);
      op00 = expand_normal (TREE_OPERAND (treeop0, 0));
      op01 = expand_normal (TREE_OPERAND (treeop0, 1));
      unsignedp = TYPE_UNSIGNED (type);
      comparison_mode = TYPE_MODE (type);
      comparison_code = convert_tree_comp_to_rtx (cmpcode, unsignedp);
    }
  else
    {
      op00 = expand_normal (treeop0);
      op01 = const0_rtx;
      comparison_code = NE;
      comparison_mode = TYPE_MODE (TREE_TYPE (treeop0));
    }

  if (GET_MODE (op1) != mode)
    op1 = gen_lowpart (mode, op1);

  if (GET_MODE (op2) != mode)
    op2 = gen_lowpart (mode, op2);

  /* Try to emit the conditional move.  */
  insn = emit_conditional_move (temp, comparison_code,
                                op00, op01, comparison_mode,
                                op1, op2, mode,
                                unsignedp);

  /* If we could do the conditional move, emit the sequence,
     and return.  */
  if (insn)
    {
      rtx_insn *seq = get_insns ();
      end_sequence ();
      emit_insn (seq);
      return convert_modes (orig_mode, mode, temp, 0);
    }

  /* Otherwise discard the sequence and fall back to code with
     branches.  */
  end_sequence ();
#endif
  return NULL_RTX;
}

rtx
expand_expr_real_2 (sepops ops, rtx target, machine_mode tmode,
                    enum expand_modifier modifier)
{
  rtx op0, op1, op2, temp;
  tree type;
  int unsignedp;
  machine_mode mode;
  enum tree_code code = ops->code;
  optab this_optab;
  rtx subtarget, original_target;
  int ignore;
  bool reduce_bit_field;
  location_t loc = ops->location;
  tree treeop0, treeop1, treeop2;
#define REDUCE_BIT_FIELD(expr)  (reduce_bit_field                         \
                                 ? reduce_to_bit_field_precision ((expr), \
                                                                  target, \
                                                                  type)   \
                                 : (expr))

  type = ops->type;
  mode = TYPE_MODE (type);
  unsignedp = TYPE_UNSIGNED (type);

  treeop0 = ops->op0;
  treeop1 = ops->op1;
  treeop2 = ops->op2;

  /* We should be called only on simple (binary or unary) expressions,
     exactly those that are valid in gimple expressions that aren't
     GIMPLE_SINGLE_RHS (or invalid).  */
  gcc_assert (get_gimple_rhs_class (code) == GIMPLE_UNARY_RHS
              || get_gimple_rhs_class (code) == GIMPLE_BINARY_RHS
              || get_gimple_rhs_class (code) == GIMPLE_TERNARY_RHS);

  ignore = (target == const0_rtx
            || ((CONVERT_EXPR_CODE_P (code)
                 || code == COND_EXPR || code == VIEW_CONVERT_EXPR)
                && TREE_CODE (type) == VOID_TYPE));

  /* We should be called only if we need the result.  */
  gcc_assert (!ignore);

  /* An operation in what may be a bit-field type needs the
     result to be reduced to the precision of the bit-field type,
     which is narrower than that of the type's mode.  */
  reduce_bit_field = (INTEGRAL_TYPE_P (type)
                      && GET_MODE_PRECISION (mode) > TYPE_PRECISION (type));

  if (reduce_bit_field && modifier == EXPAND_STACK_PARM)
    target = 0;

  /* Use subtarget as the target for operand 0 of a binary operation.  */
  subtarget = get_subtarget (target);
  original_target = target;

  switch (code)
    {
    case NON_LVALUE_EXPR:
    case PAREN_EXPR:
    CASE_CONVERT:
      if (treeop0 == error_mark_node)
        return const0_rtx;

      if (TREE_CODE (type) == UNION_TYPE)
        {
          tree valtype = TREE_TYPE (treeop0);

          /* If both input and output are BLKmode, this conversion isn't doing
             anything except possibly changing memory attribute.  */
          if (mode == BLKmode && TYPE_MODE (valtype) == BLKmode)
            {
              rtx result = expand_expr (treeop0, target, tmode,
                                        modifier);

              result = copy_rtx (result);
              set_mem_attributes (result, type, 0);
              return result;
            }

          if (target == 0)
            {
              if (TYPE_MODE (type) != BLKmode)
                target = gen_reg_rtx (TYPE_MODE (type));
              else
                target = assign_temp (type, 1, 1);
            }

          if (MEM_P (target))
            /* Store data into beginning of memory target.  */
            store_expr (treeop0,
                        adjust_address (target, TYPE_MODE (valtype), 0),
                        modifier == EXPAND_STACK_PARM,
                        false);

          else
            {
              gcc_assert (REG_P (target));

              /* Store this field into a union of the proper type.  */
              store_field (target,
                           MIN ((int_size_in_bytes (TREE_TYPE
                                                    (treeop0))
                                 * BITS_PER_UNIT),
                                (HOST_WIDE_INT) GET_MODE_BITSIZE (mode)),
                           0, 0, 0, TYPE_MODE (valtype), treeop0, 0, false);
            }

          /* Return the entire union.  */
          return target;
        }

      if (mode == TYPE_MODE (TREE_TYPE (treeop0)))
        {
          op0 = expand_expr (treeop0, target, VOIDmode,
                             modifier);

          /* If the signedness of the conversion differs and OP0 is
             a promoted SUBREG, clear that indication since we now
             have to do the proper extension.  */
          if (TYPE_UNSIGNED (TREE_TYPE (treeop0)) != unsignedp
              && GET_CODE (op0) == SUBREG)
            SUBREG_PROMOTED_VAR_P (op0) = 0;

          return REDUCE_BIT_FIELD (op0);
        }

      op0 = expand_expr (treeop0, NULL_RTX, mode,
                         modifier == EXPAND_SUM ? EXPAND_NORMAL : modifier);
      if (GET_MODE (op0) == mode)
        ;

      /* If OP0 is a constant, just convert it into the proper mode.  */
      else if (CONSTANT_P (op0))
        {
          tree inner_type = TREE_TYPE (treeop0);
          machine_mode inner_mode = GET_MODE (op0);

          if (inner_mode == VOIDmode)
            inner_mode = TYPE_MODE (inner_type);

          if (modifier == EXPAND_INITIALIZER)
            op0 = simplify_gen_subreg (mode, op0, inner_mode,
                                       subreg_lowpart_offset (mode,
                                                              inner_mode));
          else
            op0=  convert_modes (mode, inner_mode, op0,
                                 TYPE_UNSIGNED (inner_type));
        }

      else if (modifier == EXPAND_INITIALIZER)
        op0 = gen_rtx_fmt_e (unsignedp ? ZERO_EXTEND : SIGN_EXTEND, mode, op0);

      else if (target == 0)
        op0 = convert_to_mode (mode, op0,
                               TYPE_UNSIGNED (TREE_TYPE
                                              (treeop0)));
      else
        {
          convert_move (target, op0,
                        TYPE_UNSIGNED (TREE_TYPE (treeop0)));
          op0 = target;
        }

      return REDUCE_BIT_FIELD (op0);

    case ADDR_SPACE_CONVERT_EXPR:
      {
        tree treeop0_type = TREE_TYPE (treeop0);
        addr_space_t as_to;
        addr_space_t as_from;

        gcc_assert (POINTER_TYPE_P (type));
        gcc_assert (POINTER_TYPE_P (treeop0_type));

        as_to = TYPE_ADDR_SPACE (TREE_TYPE (type));
        as_from = TYPE_ADDR_SPACE (TREE_TYPE (treeop0_type));

        /* Conversions between pointers to the same address space should
           have been implemented via CONVERT_EXPR / NOP_EXPR.  */
        gcc_assert (as_to != as_from);

        /* Ask target code to handle conversion between pointers
           to overlapping address spaces.  */
        if (targetm.addr_space.subset_p (as_to, as_from)
            || targetm.addr_space.subset_p (as_from, as_to))
          {
            op0 = expand_expr (treeop0, NULL_RTX, VOIDmode, modifier);
            op0 = targetm.addr_space.convert (op0, treeop0_type, type);
            gcc_assert (op0);
            return op0;
          }

        /* For disjoint address spaces, converting anything but
           a null pointer invokes undefined behaviour.  We simply
           always return a null pointer here.  */
        return CONST0_RTX (mode);
      }

    case POINTER_PLUS_EXPR:
      /* Even though the sizetype mode and the pointer's mode can be different
         expand is able to handle this correctly and get the correct result out
         of the PLUS_EXPR code.  */
      /* Make sure to sign-extend the sizetype offset in a POINTER_PLUS_EXPR
         if sizetype precision is smaller than pointer precision.  */
      if (TYPE_PRECISION (sizetype) < TYPE_PRECISION (type))
        treeop1 = fold_convert_loc (loc, type,
                                    fold_convert_loc (loc, ssizetype,
                                                      treeop1));
      /* If sizetype precision is larger than pointer precision, truncate the
         offset to have matching modes.  */
      else if (TYPE_PRECISION (sizetype) > TYPE_PRECISION (type))
        treeop1 = fold_convert_loc (loc, type, treeop1);

    case PLUS_EXPR:
      /* If we are adding a constant, a VAR_DECL that is sp, fp, or ap, and
         something else, make sure we add the register to the constant and
         then to the other thing.  This case can occur during strength
         reduction and doing it this way will produce better code if the
         frame pointer or argument pointer is eliminated.

         fold-const.c will ensure that the constant is always in the inner
         PLUS_EXPR, so the only case we need to do anything about is if
         sp, ap, or fp is our second argument, in which case we must swap
         the innermost first argument and our second argument.  */

      if (TREE_CODE (treeop0) == PLUS_EXPR
          && TREE_CODE (TREE_OPERAND (treeop0, 1)) == INTEGER_CST
          && TREE_CODE (treeop1) == VAR_DECL
          && (DECL_RTL (treeop1) == frame_pointer_rtx
              || DECL_RTL (treeop1) == stack_pointer_rtx
              || DECL_RTL (treeop1) == arg_pointer_rtx))
        {
          gcc_unreachable ();
        }

      /* If the result is to be ptr_mode and we are adding an integer to
         something, we might be forming a constant.  So try to use
         plus_constant.  If it produces a sum and we can't accept it,
         use force_operand.  This allows P = &ARR[const] to generate
         efficient code on machines where a SYMBOL_REF is not a valid
         address.

         If this is an EXPAND_SUM call, always return the sum.  */
      if (modifier == EXPAND_SUM || modifier == EXPAND_INITIALIZER
          || (mode == ptr_mode && (unsignedp || ! flag_trapv)))
        {
          if (modifier == EXPAND_STACK_PARM)
            target = 0;
          if (TREE_CODE (treeop0) == INTEGER_CST
              && GET_MODE_PRECISION (mode) <= HOST_BITS_PER_WIDE_INT
              && TREE_CONSTANT (treeop1))
            {
              rtx constant_part;
              HOST_WIDE_INT wc;
              machine_mode wmode = TYPE_MODE (TREE_TYPE (treeop1));

              op1 = expand_expr (treeop1, subtarget, VOIDmode,
                                 EXPAND_SUM);
              /* Use wi::shwi to ensure that the constant is
                 truncated according to the mode of OP1, then sign extended
                 to a HOST_WIDE_INT.  Using the constant directly can result
                 in non-canonical RTL in a 64x32 cross compile.  */
              wc = TREE_INT_CST_LOW (treeop0);
              constant_part =
                immed_wide_int_const (wi::shwi (wc, wmode), wmode);
              op1 = plus_constant (mode, op1, INTVAL (constant_part));
              if (modifier != EXPAND_SUM && modifier != EXPAND_INITIALIZER)
                op1 = force_operand (op1, target);
              return REDUCE_BIT_FIELD (op1);
            }

          else if (TREE_CODE (treeop1) == INTEGER_CST
                   && GET_MODE_PRECISION (mode) <= HOST_BITS_PER_WIDE_INT
                   && TREE_CONSTANT (treeop0))
            {
              rtx constant_part;
              HOST_WIDE_INT wc;
              machine_mode wmode = TYPE_MODE (TREE_TYPE (treeop0));

              op0 = expand_expr (treeop0, subtarget, VOIDmode,
                                 (modifier == EXPAND_INITIALIZER
                                 ? EXPAND_INITIALIZER : EXPAND_SUM));
              if (! CONSTANT_P (op0))
                {
                  op1 = expand_expr (treeop1, NULL_RTX,
                                     VOIDmode, modifier);
                  /* Return a PLUS if modifier says it's OK.  */
                  if (modifier == EXPAND_SUM
                      || modifier == EXPAND_INITIALIZER)
                    return simplify_gen_binary (PLUS, mode, op0, op1);
                  goto binop2;
                }
              /* Use wi::shwi to ensure that the constant is
                 truncated according to the mode of OP1, then sign extended
                 to a HOST_WIDE_INT.  Using the constant directly can result
                 in non-canonical RTL in a 64x32 cross compile.  */
              wc = TREE_INT_CST_LOW (treeop1);
              constant_part
                = immed_wide_int_const (wi::shwi (wc, wmode), wmode);
              op0 = plus_constant (mode, op0, INTVAL (constant_part));
              if (modifier != EXPAND_SUM && modifier != EXPAND_INITIALIZER)
                op0 = force_operand (op0, target);
              return REDUCE_BIT_FIELD (op0);
            }
        }

      /* Use TER to expand pointer addition of a negated value
         as pointer subtraction.  */
      if ((POINTER_TYPE_P (TREE_TYPE (treeop0))
           || (TREE_CODE (TREE_TYPE (treeop0)) == VECTOR_TYPE
               && POINTER_TYPE_P (TREE_TYPE (TREE_TYPE (treeop0)))))
          && TREE_CODE (treeop1) == SSA_NAME
          && TYPE_MODE (TREE_TYPE (treeop0))
             == TYPE_MODE (TREE_TYPE (treeop1)))
        {
          gimple def = get_def_for_expr (treeop1, NEGATE_EXPR);
          if (def)
            {
              treeop1 = gimple_assign_rhs1 (def);
              code = MINUS_EXPR;
              goto do_minus;
            }
        }

      /* No sense saving up arithmetic to be done
         if it's all in the wrong mode to form part of an address.
         And force_operand won't know whether to sign-extend or
         zero-extend.  */
      if ((modifier != EXPAND_SUM && modifier != EXPAND_INITIALIZER)
          || mode != ptr_mode)
        {
          expand_operands (treeop0, treeop1,
                           subtarget, &op0, &op1, EXPAND_NORMAL);
          if (op0 == const0_rtx)
            return op1;
          if (op1 == const0_rtx)
            return op0;
          goto binop2;
        }

      expand_operands (treeop0, treeop1,
                       subtarget, &op0, &op1, modifier);
      return REDUCE_BIT_FIELD (simplify_gen_binary (PLUS, mode, op0, op1));

    case MINUS_EXPR:
    do_minus:
      /* For initializers, we are allowed to return a MINUS of two
         symbolic constants.  Here we handle all cases when both operands
         are constant.  */
      /* Handle difference of two symbolic constants,
         for the sake of an initializer.  */
      if ((modifier == EXPAND_SUM || modifier == EXPAND_INITIALIZER)
          && really_constant_p (treeop0)
          && really_constant_p (treeop1))
        {
          expand_operands (treeop0, treeop1,
                           NULL_RTX, &op0, &op1, modifier);

          /* If the last operand is a CONST_INT, use plus_constant of
             the negated constant.  Else make the MINUS.  */
          if (CONST_INT_P (op1))
            return REDUCE_BIT_FIELD (plus_constant (mode, op0,
                                                    -INTVAL (op1)));
          else
            return REDUCE_BIT_FIELD (gen_rtx_MINUS (mode, op0, op1));
        }

      /* No sense saving up arithmetic to be done
         if it's all in the wrong mode to form part of an address.
         And force_operand won't know whether to sign-extend or
         zero-extend.  */
      if ((modifier != EXPAND_SUM && modifier != EXPAND_INITIALIZER)
          || mode != ptr_mode)
        goto binop;

      expand_operands (treeop0, treeop1,
                       subtarget, &op0, &op1, modifier);

      /* Convert A - const to A + (-const).  */
      if (CONST_INT_P (op1))
        {
          op1 = negate_rtx (mode, op1);
          return REDUCE_BIT_FIELD (simplify_gen_binary (PLUS, mode, op0, op1));
        }

      goto binop2;

    case WIDEN_MULT_PLUS_EXPR:
    case WIDEN_MULT_MINUS_EXPR:
      expand_operands (treeop0, treeop1, NULL_RTX, &op0, &op1, EXPAND_NORMAL);
      op2 = expand_normal (treeop2);
      target = expand_widen_pattern_expr (ops, op0, op1, op2,
                                          target, unsignedp);
      return target;

    case WIDEN_MULT_EXPR:
      /* If first operand is constant, swap them.
         Thus the following special case checks need only
         check the second operand.  */
      if (TREE_CODE (treeop0) == INTEGER_CST)
        {
          tree t1 = treeop0;
          treeop0 = treeop1;
          treeop1 = t1;
        }

      /* First, check if we have a multiplication of one signed and one
         unsigned operand.  */
      if (TREE_CODE (treeop1) != INTEGER_CST
          && (TYPE_UNSIGNED (TREE_TYPE (treeop0))
              != TYPE_UNSIGNED (TREE_TYPE (treeop1))))
        {
          machine_mode innermode = TYPE_MODE (TREE_TYPE (treeop0));
          this_optab = usmul_widen_optab;
          if (find_widening_optab_handler (this_optab, mode, innermode, 0)
                != CODE_FOR_nothing)
            {
              if (TYPE_UNSIGNED (TREE_TYPE (treeop0)))
                expand_operands (treeop0, treeop1, NULL_RTX, &op0, &op1,
                                 EXPAND_NORMAL);
              else
                expand_operands (treeop0, treeop1, NULL_RTX, &op1, &op0,
                                 EXPAND_NORMAL);
              /* op0 and op1 might still be constant, despite the above
                 != INTEGER_CST check.  Handle it.  */
              if (GET_MODE (op0) == VOIDmode && GET_MODE (op1) == VOIDmode)
                {
                  op0 = convert_modes (innermode, mode, op0, true);
                  op1 = convert_modes (innermode, mode, op1, false);
                  return REDUCE_BIT_FIELD (expand_mult (mode, op0, op1,
                                                        target, unsignedp));
                }
              goto binop3;
            }
        }
      /* Check for a multiplication with matching signedness.  */
      else if ((TREE_CODE (treeop1) == INTEGER_CST
                && int_fits_type_p (treeop1, TREE_TYPE (treeop0)))
               || (TYPE_UNSIGNED (TREE_TYPE (treeop1))
                   == TYPE_UNSIGNED (TREE_TYPE (treeop0))))
        {
          tree op0type = TREE_TYPE (treeop0);
          machine_mode innermode = TYPE_MODE (op0type);
          bool zextend_p = TYPE_UNSIGNED (op0type);
          optab other_optab = zextend_p ? smul_widen_optab : umul_widen_optab;
          this_optab = zextend_p ? umul_widen_optab : smul_widen_optab;

          if (TREE_CODE (treeop0) != INTEGER_CST)
            {
              if (find_widening_optab_handler (this_optab, mode, innermode, 0)
                    != CODE_FOR_nothing)
                {
                  expand_operands (treeop0, treeop1, NULL_RTX, &op0, &op1,
                                   EXPAND_NORMAL);
                  /* op0 and op1 might still be constant, despite the above
                     != INTEGER_CST check.  Handle it.  */
                  if (GET_MODE (op0) == VOIDmode && GET_MODE (op1) == VOIDmode)
                    {
                     widen_mult_const:
                      op0 = convert_modes (innermode, mode, op0, zextend_p);
                      op1
                        = convert_modes (innermode, mode, op1,
                                         TYPE_UNSIGNED (TREE_TYPE (treeop1)));
                      return REDUCE_BIT_FIELD (expand_mult (mode, op0, op1,
                                                            target,
                                                            unsignedp));
                    }
                  temp = expand_widening_mult (mode, op0, op1, target,
                                               unsignedp, this_optab);
                  return REDUCE_BIT_FIELD (temp);
                }
              if (find_widening_optab_handler (other_optab, mode, innermode, 0)
                    != CODE_FOR_nothing
                  && innermode == word_mode)
                {
                  rtx htem, hipart;
                  op0 = expand_normal (treeop0);
                  if (TREE_CODE (treeop1) == INTEGER_CST)
                    op1 = convert_modes (innermode, mode,
                                         expand_normal (treeop1),
                                         TYPE_UNSIGNED (TREE_TYPE (treeop1)));
                  else
                    op1 = expand_normal (treeop1);
                  /* op0 and op1 might still be constant, despite the above
                     != INTEGER_CST check.  Handle it.  */
                  if (GET_MODE (op0) == VOIDmode && GET_MODE (op1) == VOIDmode)
                    goto widen_mult_const;
                  temp = expand_binop (mode, other_optab, op0, op1, target,
                                       unsignedp, OPTAB_LIB_WIDEN);
                  hipart = gen_highpart (innermode, temp);
                  htem = expand_mult_highpart_adjust (innermode, hipart,
                                                      op0, op1, hipart,
                                                      zextend_p);
                  if (htem != hipart)
                    emit_move_insn (hipart, htem);
                  return REDUCE_BIT_FIELD (temp);
                }
            }
        }
      treeop0 = fold_build1 (CONVERT_EXPR, type, treeop0);
      treeop1 = fold_build1 (CONVERT_EXPR, type, treeop1);
      expand_operands (treeop0, treeop1, subtarget, &op0, &op1, EXPAND_NORMAL);
      return REDUCE_BIT_FIELD (expand_mult (mode, op0, op1, target, unsignedp));

    case FMA_EXPR:
      {
        optab opt = fma_optab;
        gimple def0, def2;

        /* If there is no insn for FMA, emit it as __builtin_fma{,f,l}
           call.  */
        if (optab_handler (fma_optab, mode) == CODE_FOR_nothing)
          {
            tree fn = mathfn_built_in (TREE_TYPE (treeop0), BUILT_IN_FMA);
            tree call_expr;

            gcc_assert (fn != NULL_TREE);
            call_expr = build_call_expr (fn, 3, treeop0, treeop1, treeop2);
            return expand_builtin (call_expr, target, subtarget, mode, false);
          }

        def0 = get_def_for_expr (treeop0, NEGATE_EXPR);
        def2 = get_def_for_expr (treeop2, NEGATE_EXPR);

        op0 = op2 = NULL;

        if (def0 && def2
            && optab_handler (fnms_optab, mode) != CODE_FOR_nothing)
          {
            opt = fnms_optab;
            op0 = expand_normal (gimple_assign_rhs1 (def0));
            op2 = expand_normal (gimple_assign_rhs1 (def2));
          }
        else if (def0
                 && optab_handler (fnma_optab, mode) != CODE_FOR_nothing)
          {
            opt = fnma_optab;
            op0 = expand_normal (gimple_assign_rhs1 (def0));
          }
        else if (def2
                 && optab_handler (fms_optab, mode) != CODE_FOR_nothing)
          {
            opt = fms_optab;
            op2 = expand_normal (gimple_assign_rhs1 (def2));
          }

        if (op0 == NULL)
          op0 = expand_expr (treeop0, subtarget, VOIDmode, EXPAND_NORMAL);
        if (op2 == NULL)
          op2 = expand_normal (treeop2);
        op1 = expand_normal (treeop1);

        return expand_ternary_op (TYPE_MODE (type), opt,
                                  op0, op1, op2, target, 0);
      }

    case MULT_EXPR:
      /* If this is a fixed-point operation, then we cannot use the code
         below because "expand_mult" doesn't support sat/no-sat fixed-point
         multiplications.   */
      if (ALL_FIXED_POINT_MODE_P (mode))
        goto binop;

      /* If first operand is constant, swap them.
         Thus the following special case checks need only
         check the second operand.  */
      if (TREE_CODE (treeop0) == INTEGER_CST)
        {
          tree t1 = treeop0;
          treeop0 = treeop1;
          treeop1 = t1;
        }

      /* Attempt to return something suitable for generating an
         indexed address, for machines that support that.  */

      if (modifier == EXPAND_SUM && mode == ptr_mode
          && tree_fits_shwi_p (treeop1))
        {
          tree exp1 = treeop1;

          op0 = expand_expr (treeop0, subtarget, VOIDmode,
                             EXPAND_SUM);

          if (!REG_P (op0))
            op0 = force_operand (op0, NULL_RTX);
          if (!REG_P (op0))
            op0 = copy_to_mode_reg (mode, op0);

          return REDUCE_BIT_FIELD (gen_rtx_MULT (mode, op0,
                               gen_int_mode (tree_to_shwi (exp1),
                                             TYPE_MODE (TREE_TYPE (exp1)))));
        }

      if (modifier == EXPAND_STACK_PARM)
        target = 0;

      expand_operands (treeop0, treeop1, subtarget, &op0, &op1, EXPAND_NORMAL);
      return REDUCE_BIT_FIELD (expand_mult (mode, op0, op1, target, unsignedp));

    case TRUNC_DIV_EXPR:
    case FLOOR_DIV_EXPR:
    case CEIL_DIV_EXPR:
    case ROUND_DIV_EXPR:
    case EXACT_DIV_EXPR:
      /* If this is a fixed-point operation, then we cannot use the code
         below because "expand_divmod" doesn't support sat/no-sat fixed-point
         divisions.   */
      if (ALL_FIXED_POINT_MODE_P (mode))
        goto binop;

      if (modifier == EXPAND_STACK_PARM)
        target = 0;
      /* Possible optimization: compute the dividend with EXPAND_SUM
         then if the divisor is constant can optimize the case
         where some terms of the dividend have coeffs divisible by it.  */
      expand_operands (treeop0, treeop1,
                       subtarget, &op0, &op1, EXPAND_NORMAL);
      return expand_divmod (0, code, mode, op0, op1, target, unsignedp);

    case RDIV_EXPR:
      goto binop;

    case MULT_HIGHPART_EXPR:
      expand_operands (treeop0, treeop1, subtarget, &op0, &op1, EXPAND_NORMAL);
      temp = expand_mult_highpart (mode, op0, op1, target, unsignedp);
      gcc_assert (temp);
      return temp;

    case TRUNC_MOD_EXPR:
    case FLOOR_MOD_EXPR:
    case CEIL_MOD_EXPR:
    case ROUND_MOD_EXPR:
      if (modifier == EXPAND_STACK_PARM)
        target = 0;
      expand_operands (treeop0, treeop1,
                       subtarget, &op0, &op1, EXPAND_NORMAL);
      return expand_divmod (1, code, mode, op0, op1, target, unsignedp);

    case FIXED_CONVERT_EXPR:
      op0 = expand_normal (treeop0);
      if (target == 0 || modifier == EXPAND_STACK_PARM)
        target = gen_reg_rtx (mode);

      if ((TREE_CODE (TREE_TYPE (treeop0)) == INTEGER_TYPE
           && TYPE_UNSIGNED (TREE_TYPE (treeop0)))
          || (TREE_CODE (type) == INTEGER_TYPE && TYPE_UNSIGNED (type)))
        expand_fixed_convert (target, op0, 1, TYPE_SATURATING (type));
      else
        expand_fixed_convert (target, op0, 0, TYPE_SATURATING (type));
      return target;

    case FIX_TRUNC_EXPR:
      op0 = expand_normal (treeop0);
      if (target == 0 || modifier == EXPAND_STACK_PARM)
        target = gen_reg_rtx (mode);
      expand_fix (target, op0, unsignedp);
      return target;

    case FLOAT_EXPR:
      op0 = expand_normal (treeop0);
      if (target == 0 || modifier == EXPAND_STACK_PARM)
        target = gen_reg_rtx (mode);
      /* expand_float can't figure out what to do if FROM has VOIDmode.
         So give it the correct mode.  With -O, cse will optimize this.  */
      if (GET_MODE (op0) == VOIDmode)
        op0 = copy_to_mode_reg (TYPE_MODE (TREE_TYPE (treeop0)),
                                op0);
      expand_float (target, op0,
                    TYPE_UNSIGNED (TREE_TYPE (treeop0)));
      return target;

    case NEGATE_EXPR:
      op0 = expand_expr (treeop0, subtarget,
                         VOIDmode, EXPAND_NORMAL);
      if (modifier == EXPAND_STACK_PARM)
        target = 0;
      temp = expand_unop (mode,
                          optab_for_tree_code (NEGATE_EXPR, type,
                                               optab_default),
                          op0, target, 0);
      gcc_assert (temp);
      return REDUCE_BIT_FIELD (temp);

    case ABS_EXPR:
      op0 = expand_expr (treeop0, subtarget,
                         VOIDmode, EXPAND_NORMAL);
      if (modifier == EXPAND_STACK_PARM)
        target = 0;

      /* ABS_EXPR is not valid for complex arguments.  */
      gcc_assert (GET_MODE_CLASS (mode) != MODE_COMPLEX_INT
                  && GET_MODE_CLASS (mode) != MODE_COMPLEX_FLOAT);

      /* Unsigned abs is simply the operand.  Testing here means we don't
         risk generating incorrect code below.  */
      if (TYPE_UNSIGNED (type))
        return op0;

      return expand_abs (mode, op0, target, unsignedp,
                         safe_from_p (target, treeop0, 1));

    case MAX_EXPR:
    case MIN_EXPR:
      target = original_target;
      if (target == 0
          || modifier == EXPAND_STACK_PARM
          || (MEM_P (target) && MEM_VOLATILE_P (target))
          || GET_MODE (target) != mode
          || (REG_P (target)
              && REGNO (target) < FIRST_PSEUDO_REGISTER))
        target = gen_reg_rtx (mode);
      expand_operands (treeop0, treeop1,
                       target, &op0, &op1, EXPAND_NORMAL);

      /* First try to do it with a special MIN or MAX instruction.
         If that does not win, use a conditional jump to select the proper
         value.  */
      this_optab = optab_for_tree_code (code, type, optab_default);
      temp = expand_binop (mode, this_optab, op0, op1, target, unsignedp,
                           OPTAB_WIDEN);
      if (temp != 0)
        return temp;

      /* At this point, a MEM target is no longer useful; we will get better
         code without it.  */

      if (! REG_P (target))
        target = gen_reg_rtx (mode);

      /* If op1 was placed in target, swap op0 and op1.  */
      if (target != op0 && target == op1)
        {
          temp = op0;
          op0 = op1;
          op1 = temp;
        }

      /* We generate better code and avoid problems with op1 mentioning
         target by forcing op1 into a pseudo if it isn't a constant.  */
      if (! CONSTANT_P (op1))
        op1 = force_reg (mode, op1);

      {
        enum rtx_code comparison_code;
        rtx cmpop1 = op1;

        if (code == MAX_EXPR)
          comparison_code = unsignedp ? GEU : GE;
        else
          comparison_code = unsignedp ? LEU : LE;

        /* Canonicalize to comparisons against 0.  */
        if (op1 == const1_rtx)
          {
            /* Converting (a >= 1 ? a : 1) into (a > 0 ? a : 1)
               or (a != 0 ? a : 1) for unsigned.
               For MIN we are safe converting (a <= 1 ? a : 1)
               into (a <= 0 ? a : 1)  */
            cmpop1 = const0_rtx;
            if (code == MAX_EXPR)
              comparison_code = unsignedp ? NE : GT;
          }
        if (op1 == constm1_rtx && !unsignedp)
          {
            /* Converting (a >= -1 ? a : -1) into (a >= 0 ? a : -1)
               and (a <= -1 ? a : -1) into (a < 0 ? a : -1) */
            cmpop1 = const0_rtx;
            if (code == MIN_EXPR)
              comparison_code = LT;
          }
#ifdef HAVE_conditional_move
        /* Use a conditional move if possible.  */
        if (can_conditionally_move_p (mode))
          {
            rtx insn;

            start_sequence ();

            /* Try to emit the conditional move.  */
            insn = emit_conditional_move (target, comparison_code,
                                          op0, cmpop1, mode,
                                          op0, op1, mode,
                                          unsignedp);

            /* If we could do the conditional move, emit the sequence,
               and return.  */
            if (insn)
              {
                rtx_insn *seq = get_insns ();
                end_sequence ();
                emit_insn (seq);
                return target;
              }

            /* Otherwise discard the sequence and fall back to code with
               branches.  */
            end_sequence ();
          }
#endif
        if (target != op0)
          emit_move_insn (target, op0);

        temp = gen_label_rtx ();
        do_compare_rtx_and_jump (target, cmpop1, comparison_code,
                                 unsignedp, mode, NULL_RTX, NULL_RTX, temp,
                                 -1);
      }
      emit_move_insn (target, op1);
      emit_label (temp);
      return target;

    case BIT_NOT_EXPR:
      op0 = expand_expr (treeop0, subtarget,
                         VOIDmode, EXPAND_NORMAL);
      if (modifier == EXPAND_STACK_PARM)
        target = 0;
      /* In case we have to reduce the result to bitfield precision
         for unsigned bitfield expand this as XOR with a proper constant
         instead.  */
      if (reduce_bit_field && TYPE_UNSIGNED (type))
        {
          wide_int mask = wi::mask (TYPE_PRECISION (type),
                                    false, GET_MODE_PRECISION (mode));

          temp = expand_binop (mode, xor_optab, op0,
                               immed_wide_int_const (mask, mode),
                               target, 1, OPTAB_LIB_WIDEN);
        }
      else
        temp = expand_unop (mode, one_cmpl_optab, op0, target, 1);
      gcc_assert (temp);
      return temp;

      /* ??? Can optimize bitwise operations with one arg constant.
         Can optimize (a bitwise1 n) bitwise2 (a bitwise3 b)
         and (a bitwise1 b) bitwise2 b (etc)
         but that is probably not worth while.  */

    case BIT_AND_EXPR:
    case BIT_IOR_EXPR:
    case BIT_XOR_EXPR:
      goto binop;

    case LROTATE_EXPR:
    case RROTATE_EXPR:
      gcc_assert (VECTOR_MODE_P (TYPE_MODE (type))
                  || (GET_MODE_PRECISION (TYPE_MODE (type))
                      == TYPE_PRECISION (type)));
      /* fall through */

    case LSHIFT_EXPR:
    case RSHIFT_EXPR:
      /* If this is a fixed-point operation, then we cannot use the code
         below because "expand_shift" doesn't support sat/no-sat fixed-point
         shifts.   */
      if (ALL_FIXED_POINT_MODE_P (mode))
        goto binop;

      if (! safe_from_p (subtarget, treeop1, 1))
        subtarget = 0;
      if (modifier == EXPAND_STACK_PARM)
        target = 0;
      op0 = expand_expr (treeop0, subtarget,
                         VOIDmode, EXPAND_NORMAL);
      temp = expand_variable_shift (code, mode, op0, treeop1, target,
                                    unsignedp);
      if (code == LSHIFT_EXPR)
        temp = REDUCE_BIT_FIELD (temp);
      return temp;

      /* Could determine the answer when only additive constants differ.  Also,
         the addition of one can be handled by changing the condition.  */
    case LT_EXPR:
    case LE_EXPR:
    case GT_EXPR:
    case GE_EXPR:
    case EQ_EXPR:
    case NE_EXPR:
    case UNORDERED_EXPR:
    case ORDERED_EXPR:
    case UNLT_EXPR:
    case UNLE_EXPR:
    case UNGT_EXPR:
    case UNGE_EXPR:
    case UNEQ_EXPR:
    case LTGT_EXPR:
      temp = do_store_flag (ops,
                            modifier != EXPAND_STACK_PARM ? target : NULL_RTX,
                            tmode != VOIDmode ? tmode : mode);
      if (temp)
        return temp;

      /* Use a compare and a jump for BLKmode comparisons, or for function
         type comparisons is HAVE_canonicalize_funcptr_for_compare.  */

      if ((target == 0
           || modifier == EXPAND_STACK_PARM
           || ! safe_from_p (target, treeop0, 1)
           || ! safe_from_p (target, treeop1, 1)
           /* Make sure we don't have a hard reg (such as function's return
              value) live across basic blocks, if not optimizing.  */
           || (!optimize && REG_P (target)
               && REGNO (target) < FIRST_PSEUDO_REGISTER)))
        target = gen_reg_rtx (tmode != VOIDmode ? tmode : mode);

      emit_move_insn (target, const0_rtx);

      op1 = gen_label_rtx ();
      jumpifnot_1 (code, treeop0, treeop1, op1, -1);

      if (TYPE_PRECISION (type) == 1 && !TYPE_UNSIGNED (type))
        emit_move_insn (target, constm1_rtx);
      else
        emit_move_insn (target, const1_rtx);

      emit_label (op1);
      return target;

    case COMPLEX_EXPR:
      /* Get the rtx code of the operands.  */
      op0 = expand_normal (treeop0);
      op1 = expand_normal (treeop1);

      if (!target)
        target = gen_reg_rtx (TYPE_MODE (type));
      else
        /* If target overlaps with op1, then either we need to force
           op1 into a pseudo (if target also overlaps with op0),
           or write the complex parts in reverse order.  */
        switch (GET_CODE (target))
          {
          case CONCAT:
            if (reg_overlap_mentioned_p (XEXP (target, 0), op1))
              {
                if (reg_overlap_mentioned_p (XEXP (target, 1), op0))
                  {
                  complex_expr_force_op1:
                    temp = gen_reg_rtx (GET_MODE_INNER (GET_MODE (target)));
                    emit_move_insn (temp, op1);
                    op1 = temp;
                    break;
                  }
              complex_expr_swap_order:
                /* Move the imaginary (op1) and real (op0) parts to their
                   location.  */
                write_complex_part (target, op1, true);
                write_complex_part (target, op0, false);

                return target;
              }
            break;
          case MEM:
            temp = adjust_address_nv (target,
                                      GET_MODE_INNER (GET_MODE (target)), 0);
            if (reg_overlap_mentioned_p (temp, op1))
              {
                machine_mode imode = GET_MODE_INNER (GET_MODE (target));
                temp = adjust_address_nv (target, imode,
                                          GET_MODE_SIZE (imode));
                if (reg_overlap_mentioned_p (temp, op0))
                  goto complex_expr_force_op1;
                goto complex_expr_swap_order;
              }
            break;
          default:
            if (reg_overlap_mentioned_p (target, op1))
              {
                if (reg_overlap_mentioned_p (target, op0))
                  goto complex_expr_force_op1;
                goto complex_expr_swap_order;
              }
            break;
          }

      /* Move the real (op0) and imaginary (op1) parts to their location.  */
      write_complex_part (target, op0, false);
      write_complex_part (target, op1, true);

      return target;

    case WIDEN_SUM_EXPR:
      {
        tree oprnd0 = treeop0;
        tree oprnd1 = treeop1;

        expand_operands (oprnd0, oprnd1, NULL_RTX, &op0, &op1, EXPAND_NORMAL);
        target = expand_widen_pattern_expr (ops, op0, NULL_RTX, op1,
                                            target, unsignedp);
        return target;
      }

    case REDUC_MAX_EXPR:
    case REDUC_MIN_EXPR:
    case REDUC_PLUS_EXPR:
      {
        op0 = expand_normal (treeop0);
        this_optab = optab_for_tree_code (code, type, optab_default);
        machine_mode vec_mode = TYPE_MODE (TREE_TYPE (treeop0));

        if (optab_handler (this_optab, vec_mode) != CODE_FOR_nothing)
          {
            struct expand_operand ops[2];
            enum insn_code icode = optab_handler (this_optab, vec_mode);

            create_output_operand (&ops[0], target, mode);
            create_input_operand (&ops[1], op0, vec_mode);
            if (maybe_expand_insn (icode, 2, ops))
              {
                target = ops[0].value;
                if (GET_MODE (target) != mode)
                  return gen_lowpart (tmode, target);
                return target;
              }
          }
        /* Fall back to optab with vector result, and then extract scalar.  */
        this_optab = scalar_reduc_to_vector (this_optab, type);
        temp = expand_unop (vec_mode, this_optab, op0, NULL_RTX, unsignedp);
        gcc_assert (temp);
        /* The tree code produces a scalar result, but (somewhat by convention)
           the optab produces a vector with the result in element 0 if
           little-endian, or element N-1 if big-endian.  So pull the scalar
           result out of that element.  */
        int index = BYTES_BIG_ENDIAN ? GET_MODE_NUNITS (vec_mode) - 1 : 0;
        int bitsize = GET_MODE_BITSIZE (GET_MODE_INNER (vec_mode));
        temp = extract_bit_field (temp, bitsize, bitsize * index, unsignedp,
                                  target, mode, mode);
        gcc_assert (temp);
        return temp;
      }

    case VEC_RSHIFT_EXPR:
      {
        target = expand_vec_shift_expr (ops, target);
        return target;
      }

    case VEC_UNPACK_HI_EXPR:
    case VEC_UNPACK_LO_EXPR:
      {
        op0 = expand_normal (treeop0);
        temp = expand_widen_pattern_expr (ops, op0, NULL_RTX, NULL_RTX,
                                          target, unsignedp);
        gcc_assert (temp);
        return temp;
      }

    case VEC_UNPACK_FLOAT_HI_EXPR:
    case VEC_UNPACK_FLOAT_LO_EXPR:
      {
        op0 = expand_normal (treeop0);
        /* The signedness is determined from input operand.  */
        temp = expand_widen_pattern_expr
          (ops, op0, NULL_RTX, NULL_RTX,
           target, TYPE_UNSIGNED (TREE_TYPE (treeop0)));

        gcc_assert (temp);
        return temp;
      }

    case VEC_WIDEN_MULT_HI_EXPR:
    case VEC_WIDEN_MULT_LO_EXPR:
    case VEC_WIDEN_MULT_EVEN_EXPR:
    case VEC_WIDEN_MULT_ODD_EXPR:
    case VEC_WIDEN_LSHIFT_HI_EXPR:
    case VEC_WIDEN_LSHIFT_LO_EXPR:
      expand_operands (treeop0, treeop1, NULL_RTX, &op0, &op1, EXPAND_NORMAL);
      target = expand_widen_pattern_expr (ops, op0, op1, NULL_RTX,
                                          target, unsignedp);
      gcc_assert (target);
      return target;

    case VEC_PACK_TRUNC_EXPR:
    case VEC_PACK_SAT_EXPR:
    case VEC_PACK_FIX_TRUNC_EXPR:
      mode = TYPE_MODE (TREE_TYPE (treeop0));
      goto binop;

    case VEC_PERM_EXPR:
      expand_operands (treeop0, treeop1, target, &op0, &op1, EXPAND_NORMAL);
      op2 = expand_normal (treeop2);

      /* Careful here: if the target doesn't support integral vector modes,
         a constant selection vector could wind up smooshed into a normal
         integral constant.  */
      if (CONSTANT_P (op2) && GET_CODE (op2) != CONST_VECTOR)
        {
          tree sel_type = TREE_TYPE (treeop2);
          machine_mode vmode
            = mode_for_vector (TYPE_MODE (TREE_TYPE (sel_type)),
                               TYPE_VECTOR_SUBPARTS (sel_type));
          gcc_assert (GET_MODE_CLASS (vmode) == MODE_VECTOR_INT);
          op2 = simplify_subreg (vmode, op2, TYPE_MODE (sel_type), 0);
          gcc_assert (op2 && GET_CODE (op2) == CONST_VECTOR);
        }
      else
        gcc_assert (GET_MODE_CLASS (GET_MODE (op2)) == MODE_VECTOR_INT);

      temp = expand_vec_perm (mode, op0, op1, op2, target);
      gcc_assert (temp);
      return temp;

    case DOT_PROD_EXPR:
      {
        tree oprnd0 = treeop0;
        tree oprnd1 = treeop1;
        tree oprnd2 = treeop2;
        rtx op2;

        expand_operands (oprnd0, oprnd1, NULL_RTX, &op0, &op1, EXPAND_NORMAL);
        op2 = expand_normal (oprnd2);
        target = expand_widen_pattern_expr (ops, op0, op1, op2,
                                            target, unsignedp);
        return target;
      }

      case SAD_EXPR:
      {
        tree oprnd0 = treeop0;
        tree oprnd1 = treeop1;
        tree oprnd2 = treeop2;
        rtx op2;

        expand_operands (oprnd0, oprnd1, NULL_RTX, &op0, &op1, EXPAND_NORMAL);
        op2 = expand_normal (oprnd2);
        target = expand_widen_pattern_expr (ops, op0, op1, op2,
                                            target, unsignedp);
        return target;
      }

    case REALIGN_LOAD_EXPR:
      {
        tree oprnd0 = treeop0;
        tree oprnd1 = treeop1;
        tree oprnd2 = treeop2;
        rtx op2;

        this_optab = optab_for_tree_code (code, type, optab_default);
        expand_operands (oprnd0, oprnd1, NULL_RTX, &op0, &op1, EXPAND_NORMAL);
        op2 = expand_normal (oprnd2);
        temp = expand_ternary_op (mode, this_optab, op0, op1, op2,
                                  target, unsignedp);
        gcc_assert (temp);
        return temp;
      }

    case COND_EXPR:
      /* A COND_EXPR with its type being VOID_TYPE represents a
         conditional jump and is handled in
         expand_gimple_cond_expr.  */
      gcc_assert (!VOID_TYPE_P (type));

      /* Note that COND_EXPRs whose type is a structure or union
         are required to be constructed to contain assignments of
         a temporary variable, so that we can evaluate them here
         for side effect only.  If type is void, we must do likewise.  */

      gcc_assert (!TREE_ADDRESSABLE (type)
                  && !ignore
                  && TREE_TYPE (treeop1) != void_type_node
                  && TREE_TYPE (treeop2) != void_type_node);

      temp = expand_cond_expr_using_cmove (treeop0, treeop1, treeop2);
      if (temp)
        return temp;

      /* If we are not to produce a result, we have no target.  Otherwise,
         if a target was specified use it; it will not be used as an
         intermediate target unless it is safe.  If no target, use a
         temporary.  */

      if (modifier != EXPAND_STACK_PARM
          && original_target
          && safe_from_p (original_target, treeop0, 1)
          && GET_MODE (original_target) == mode
          && !MEM_P (original_target))
        temp = original_target;
      else
        temp = assign_temp (type, 0, 1);

      do_pending_stack_adjust ();
      NO_DEFER_POP;
      op0 = gen_label_rtx ();
      op1 = gen_label_rtx ();
      jumpifnot (treeop0, op0, -1);
      store_expr (treeop1, temp,
                  modifier == EXPAND_STACK_PARM,
                  false);

      emit_jump_insn (gen_jump (op1));
      emit_barrier ();
      emit_label (op0);
      store_expr (treeop2, temp,
                  modifier == EXPAND_STACK_PARM,
                  false);

      emit_label (op1);
      OK_DEFER_POP;
      return temp;

    case VEC_COND_EXPR:
      target = expand_vec_cond_expr (type, treeop0, treeop1, treeop2, target);
      return target;

    default:
      gcc_unreachable ();
    }

  /* Here to do an ordinary binary operator.  */
 binop:
  expand_operands (treeop0, treeop1,
                   subtarget, &op0, &op1, EXPAND_NORMAL);
 binop2:
  this_optab = optab_for_tree_code (code, type, optab_default);
 binop3:
  if (modifier == EXPAND_STACK_PARM)
    target = 0;
  temp = expand_binop (mode, this_optab, op0, op1, target,
                       unsignedp, OPTAB_LIB_WIDEN);
  gcc_assert (temp);
  /* Bitwise operations do not need bitfield reduction as we expect their
     operands being properly truncated.  */
  if (code == BIT_XOR_EXPR
      || code == BIT_AND_EXPR
      || code == BIT_IOR_EXPR)
    return temp;
  return REDUCE_BIT_FIELD (temp);
}
#undef REDUCE_BIT_FIELD


/* Return TRUE if expression STMT is suitable for replacement.  
   Never consider memory loads as replaceable, because those don't ever lead 
   into constant expressions.  */

static bool
stmt_is_replaceable_p (gimple stmt)
{
  if (ssa_is_replaceable_p (stmt))
    {
      /* Don't move around loads.  */
      if (!gimple_assign_single_p (stmt)
          || is_gimple_val (gimple_assign_rhs1 (stmt)))
        return true;
    }
  return false;
}

rtx
expand_expr_real_1 (tree exp, rtx target, machine_mode tmode,
                    enum expand_modifier modifier, rtx *alt_rtl,
                    bool inner_reference_p)
{
  rtx op0, op1, temp, decl_rtl;
  tree type;
  int unsignedp;
  machine_mode mode;
  enum tree_code code = TREE_CODE (exp);
  rtx subtarget, original_target;
  int ignore;
  tree context;
  bool reduce_bit_field;
  location_t loc = EXPR_LOCATION (exp);
  struct separate_ops ops;
  tree treeop0, treeop1, treeop2;
  tree ssa_name = NULL_TREE;
  gimple g;

  type = TREE_TYPE (exp);
  mode = TYPE_MODE (type);
  unsignedp = TYPE_UNSIGNED (type);

  treeop0 = treeop1 = treeop2 = NULL_TREE;
  if (!VL_EXP_CLASS_P (exp))
    switch (TREE_CODE_LENGTH (code))
      {
        default:
        case 3: treeop2 = TREE_OPERAND (exp, 2);
        case 2: treeop1 = TREE_OPERAND (exp, 1);
        case 1: treeop0 = TREE_OPERAND (exp, 0);
        case 0: break;
      }
  ops.code = code;
  ops.type = type;
  ops.op0 = treeop0;
  ops.op1 = treeop1;
  ops.op2 = treeop2;
  ops.location = loc;

  ignore = (target == const0_rtx
            || ((CONVERT_EXPR_CODE_P (code)
                 || code == COND_EXPR || code == VIEW_CONVERT_EXPR)
                && TREE_CODE (type) == VOID_TYPE));

  /* An operation in what may be a bit-field type needs the
     result to be reduced to the precision of the bit-field type,
     which is narrower than that of the type's mode.  */
  reduce_bit_field = (!ignore
                      && INTEGRAL_TYPE_P (type)
                      && GET_MODE_PRECISION (mode) > TYPE_PRECISION (type));

  /* If we are going to ignore this result, we need only do something
     if there is a side-effect somewhere in the expression.  If there
     is, short-circuit the most common cases here.  Note that we must
     not call expand_expr with anything but const0_rtx in case this
     is an initial expansion of a size that contains a PLACEHOLDER_EXPR.  */

  if (ignore)
    {
      if (! TREE_SIDE_EFFECTS (exp))
        return const0_rtx;

      /* Ensure we reference a volatile object even if value is ignored, but
         don't do this if all we are doing is taking its address.  */
      if (TREE_THIS_VOLATILE (exp)
          && TREE_CODE (exp) != FUNCTION_DECL
          && mode != VOIDmode && mode != BLKmode
          && modifier != EXPAND_CONST_ADDRESS)
        {
          temp = expand_expr (exp, NULL_RTX, VOIDmode, modifier);
          if (MEM_P (temp))
            copy_to_reg (temp);
          return const0_rtx;
        }

      if (TREE_CODE_CLASS (code) == tcc_unary
          || code == BIT_FIELD_REF
          || code == COMPONENT_REF
          || code == INDIRECT_REF)
        return expand_expr (treeop0, const0_rtx, VOIDmode,
                            modifier);

      else if (TREE_CODE_CLASS (code) == tcc_binary
               || TREE_CODE_CLASS (code) == tcc_comparison
               || code == ARRAY_REF || code == ARRAY_RANGE_REF)
        {
          expand_expr (treeop0, const0_rtx, VOIDmode, modifier);
          expand_expr (treeop1, const0_rtx, VOIDmode, modifier);
          return const0_rtx;
        }

      target = 0;
    }

  if (reduce_bit_field && modifier == EXPAND_STACK_PARM)
    target = 0;

  /* Use subtarget as the target for operand 0 of a binary operation.  */
  subtarget = get_subtarget (target);
  original_target = target;

  switch (code)
    {
    case LABEL_DECL:
      {
        tree function = decl_function_context (exp);

        temp = label_rtx (exp);
        temp = gen_rtx_LABEL_REF (Pmode, temp);

        if (function != current_function_decl
            && function != 0)
          LABEL_REF_NONLOCAL_P (temp) = 1;

        temp = gen_rtx_MEM (FUNCTION_MODE, temp);
        return temp;
      }

    case SSA_NAME:
      /* ??? ivopts calls expander, without any preparation from
         out-of-ssa.  So fake instructions as if this was an access to the
         base variable.  This unnecessarily allocates a pseudo, see how we can
         reuse it, if partition base vars have it set already.  */
      if (!currently_expanding_to_rtl)
        {
          tree var = SSA_NAME_VAR (exp);
          if (var && DECL_RTL_SET_P (var))
            return DECL_RTL (var);
          return gen_raw_REG (TYPE_MODE (TREE_TYPE (exp)),
                              LAST_VIRTUAL_REGISTER + 1);
        }

      g = get_gimple_for_ssa_name (exp);
      /* For EXPAND_INITIALIZER try harder to get something simpler.  */
      if (g == NULL
          && modifier == EXPAND_INITIALIZER
          && !SSA_NAME_IS_DEFAULT_DEF (exp)
          && (optimize || DECL_IGNORED_P (SSA_NAME_VAR (exp)))
          && stmt_is_replaceable_p (SSA_NAME_DEF_STMT (exp)))
        g = SSA_NAME_DEF_STMT (exp);
      if (g)
        {
          rtx r;
          ops.code = gimple_assign_rhs_code (g);
          switch (get_gimple_rhs_class (ops.code))
            {
            case GIMPLE_TERNARY_RHS:
              ops.op2 = gimple_assign_rhs3 (g);
              /* Fallthru */
            case GIMPLE_BINARY_RHS:
              ops.op1 = gimple_assign_rhs2 (g);
              /* Fallthru */
            case GIMPLE_UNARY_RHS:
              ops.op0 = gimple_assign_rhs1 (g);
              ops.type = TREE_TYPE (gimple_assign_lhs (g));
              ops.location = gimple_location (g);
              r = expand_expr_real_2 (&ops, target, tmode, modifier);
              break;
            case GIMPLE_SINGLE_RHS:
              {
                location_t saved_loc = curr_insn_location ();
                set_curr_insn_location (gimple_location (g));
                r = expand_expr_real (gimple_assign_rhs1 (g), target,
                                      tmode, modifier, NULL, inner_reference_p);
                set_curr_insn_location (saved_loc);
                break;
              }
            default:
              gcc_unreachable ();
            }
          if (REG_P (r) && !REG_EXPR (r))
            set_reg_attrs_for_decl_rtl (SSA_NAME_VAR (exp), r);
          return r;
        }

      ssa_name = exp;
      decl_rtl = get_rtx_for_ssa_name (ssa_name);
      exp = SSA_NAME_VAR (ssa_name);
      goto expand_decl_rtl;

    case PARM_DECL:
    case VAR_DECL:
      /* If a static var's type was incomplete when the decl was written,
         but the type is complete now, lay out the decl now.  */
      if (DECL_SIZE (exp) == 0
          && COMPLETE_OR_UNBOUND_ARRAY_TYPE_P (TREE_TYPE (exp))
          && (TREE_STATIC (exp) || DECL_EXTERNAL (exp)))
        layout_decl (exp, 0);

      /* ... fall through ...  */

    case FUNCTION_DECL:
    case RESULT_DECL:
      decl_rtl = DECL_RTL (exp);
    expand_decl_rtl:
      gcc_assert (decl_rtl);
      decl_rtl = copy_rtx (decl_rtl);
      /* Record writes to register variables.  */
      if (modifier == EXPAND_WRITE
          && REG_P (decl_rtl)
          && HARD_REGISTER_P (decl_rtl))
        add_to_hard_reg_set (&crtl->asm_clobbers,
                             GET_MODE (decl_rtl), REGNO (decl_rtl));

      /* Ensure variable marked as used even if it doesn't go through
         a parser.  If it hasn't be used yet, write out an external
         definition.  */
      TREE_USED (exp) = 1;

      /* Show we haven't gotten RTL for this yet.  */
      temp = 0;

      /* Variables inherited from containing functions should have
         been lowered by this point.  */
      context = decl_function_context (exp);
      gcc_assert (SCOPE_FILE_SCOPE_P (context)
                  || context == current_function_decl
                  || TREE_STATIC (exp)
                  || DECL_EXTERNAL (exp)
                  /* ??? C++ creates functions that are not TREE_STATIC.  */
                  || TREE_CODE (exp) == FUNCTION_DECL);

      /* This is the case of an array whose size is to be determined
         from its initializer, while the initializer is still being parsed.
         ??? We aren't parsing while expanding anymore.  */

      if (MEM_P (decl_rtl) && REG_P (XEXP (decl_rtl, 0)))
        temp = validize_mem (decl_rtl);

      /* If DECL_RTL is memory, we are in the normal case and the
         address is not valid, get the address into a register.  */

      else if (MEM_P (decl_rtl) && modifier != EXPAND_INITIALIZER)
        {
          if (alt_rtl)
            *alt_rtl = decl_rtl;
          decl_rtl = use_anchored_address (decl_rtl);
          if (modifier != EXPAND_CONST_ADDRESS
              && modifier != EXPAND_SUM
              && !memory_address_addr_space_p (DECL_MODE (exp),
                                               XEXP (decl_rtl, 0),
                                               MEM_ADDR_SPACE (decl_rtl)))
            temp = replace_equiv_address (decl_rtl,
                                          copy_rtx (XEXP (decl_rtl, 0)));
        }

      /* If we got something, return it.  But first, set the alignment
         if the address is a register.  */
      if (temp != 0)
        {
          if (MEM_P (temp) && REG_P (XEXP (temp, 0)))
            mark_reg_pointer (XEXP (temp, 0), DECL_ALIGN (exp));

          return temp;
        }

      /* If the mode of DECL_RTL does not match that of the decl,
         there are two cases: we are dealing with a BLKmode value
         that is returned in a register, or we are dealing with
         a promoted value.  In the latter case, return a SUBREG
         of the wanted mode, but mark it so that we know that it
         was already extended.  */
      if (REG_P (decl_rtl)
          && DECL_MODE (exp) != BLKmode
          && GET_MODE (decl_rtl) != DECL_MODE (exp))
        {
          machine_mode pmode;

          /* Get the signedness to be used for this variable.  Ensure we get
             the same mode we got when the variable was declared.  */
          if (code == SSA_NAME
              && (g = SSA_NAME_DEF_STMT (ssa_name))
              && gimple_code (g) == GIMPLE_CALL
              && !gimple_call_internal_p (g))
            pmode = promote_function_mode (type, mode, &unsignedp,
                                           gimple_call_fntype (g),
                                           2);
          else
            pmode = promote_decl_mode (exp, &unsignedp);
          gcc_assert (GET_MODE (decl_rtl) == pmode);

          temp = gen_lowpart_SUBREG (mode, decl_rtl);
          SUBREG_PROMOTED_VAR_P (temp) = 1;
          SUBREG_PROMOTED_SET (temp, unsignedp);
          return temp;
        }

      return decl_rtl;

    case INTEGER_CST:
      /* Given that TYPE_PRECISION (type) is not always equal to
         GET_MODE_PRECISION (TYPE_MODE (type)), we need to extend from
         the former to the latter according to the signedness of the
         type. */
      temp = immed_wide_int_const (wide_int::from
                                   (exp,
                                    GET_MODE_PRECISION (TYPE_MODE (type)),
                                    TYPE_SIGN (type)),
                                   TYPE_MODE (type));
      return temp;

    case VECTOR_CST:
      {
        tree tmp = NULL_TREE;
        if (GET_MODE_CLASS (mode) == MODE_VECTOR_INT
            || GET_MODE_CLASS (mode) == MODE_VECTOR_FLOAT
            || GET_MODE_CLASS (mode) == MODE_VECTOR_FRACT
            || GET_MODE_CLASS (mode) == MODE_VECTOR_UFRACT
            || GET_MODE_CLASS (mode) == MODE_VECTOR_ACCUM
            || GET_MODE_CLASS (mode) == MODE_VECTOR_UACCUM)
          return const_vector_from_tree (exp);
        if (GET_MODE_CLASS (mode) == MODE_INT)
          {
            tree type_for_mode = lang_hooks.types.type_for_mode (mode, 1);
            if (type_for_mode)
              tmp = fold_unary_loc (loc, VIEW_CONVERT_EXPR, type_for_mode, exp);
          }
        if (!tmp)
          {
            vec<constructor_elt, va_gc> *v;
            unsigned i;
            vec_alloc (v, VECTOR_CST_NELTS (exp));
            for (i = 0; i < VECTOR_CST_NELTS (exp); ++i)
              CONSTRUCTOR_APPEND_ELT (v, NULL_TREE, VECTOR_CST_ELT (exp, i));
            tmp = build_constructor (type, v);
          }
        return expand_expr (tmp, ignore ? const0_rtx : target,
                            tmode, modifier);
      }

    case CONST_DECL:
      return expand_expr (DECL_INITIAL (exp), target, VOIDmode, modifier);

    case REAL_CST:
      /* If optimized, generate immediate CONST_DOUBLE
         which will be turned into memory by reload if necessary.

         We used to force a register so that loop.c could see it.  But
         this does not allow gen_* patterns to perform optimizations with
         the constants.  It also produces two insns in cases like "x = 1.0;".
         On most machines, floating-point constants are not permitted in
         many insns, so we'd end up copying it to a register in any case.

         Now, we do the copying in expand_binop, if appropriate.  */
      return CONST_DOUBLE_FROM_REAL_VALUE (TREE_REAL_CST (exp),
                                           TYPE_MODE (TREE_TYPE (exp)));

    case FIXED_CST:
      return CONST_FIXED_FROM_FIXED_VALUE (TREE_FIXED_CST (exp),
                                           TYPE_MODE (TREE_TYPE (exp)));

    case COMPLEX_CST:
      /* Handle evaluating a complex constant in a CONCAT target.  */
      if (original_target && GET_CODE (original_target) == CONCAT)
        {
          machine_mode mode = TYPE_MODE (TREE_TYPE (TREE_TYPE (exp)));
          rtx rtarg, itarg;

          rtarg = XEXP (original_target, 0);
          itarg = XEXP (original_target, 1);

          /* Move the real and imaginary parts separately.  */
          op0 = expand_expr (TREE_REALPART (exp), rtarg, mode, EXPAND_NORMAL);
          op1 = expand_expr (TREE_IMAGPART (exp), itarg, mode, EXPAND_NORMAL);

          if (op0 != rtarg)
            emit_move_insn (rtarg, op0);
          if (op1 != itarg)
            emit_move_insn (itarg, op1);

          return original_target;
        }

      /* ... fall through ...  */

    case STRING_CST:
      temp = expand_expr_constant (exp, 1, modifier);

      /* temp contains a constant address.
         On RISC machines where a constant address isn't valid,
         make some insns to get that address into a register.  */
      if (modifier != EXPAND_CONST_ADDRESS
          && modifier != EXPAND_INITIALIZER
          && modifier != EXPAND_SUM
          && ! memory_address_addr_space_p (mode, XEXP (temp, 0),
                                            MEM_ADDR_SPACE (temp)))
        return replace_equiv_address (temp,
                                      copy_rtx (XEXP (temp, 0)));
      return temp;

    case SAVE_EXPR:
      {
        tree val = treeop0;
        rtx ret = expand_expr_real_1 (val, target, tmode, modifier, alt_rtl,
                                      inner_reference_p);

        if (!SAVE_EXPR_RESOLVED_P (exp))
          {
            /* We can indeed still hit this case, typically via builtin
               expanders calling save_expr immediately before expanding
               something.  Assume this means that we only have to deal
               with non-BLKmode values.  */
            gcc_assert (GET_MODE (ret) != BLKmode);

            val = build_decl (curr_insn_location (),
                              VAR_DECL, NULL, TREE_TYPE (exp));
            DECL_ARTIFICIAL (val) = 1;
            DECL_IGNORED_P (val) = 1;
            treeop0 = val;
            TREE_OPERAND (exp, 0) = treeop0;
            SAVE_EXPR_RESOLVED_P (exp) = 1;

            if (!CONSTANT_P (ret))
              ret = copy_to_reg (ret);
            SET_DECL_RTL (val, ret);
          }

        return ret;
      }


    case CONSTRUCTOR:
      /* If we don't need the result, just ensure we evaluate any
         subexpressions.  */
      if (ignore)
        {
          unsigned HOST_WIDE_INT idx;
          tree value;

          FOR_EACH_CONSTRUCTOR_VALUE (CONSTRUCTOR_ELTS (exp), idx, value)
            expand_expr (value, const0_rtx, VOIDmode, EXPAND_NORMAL);

          return const0_rtx;
        }

      return expand_constructor (exp, target, modifier, false);

    case TARGET_MEM_REF:
      {
        addr_space_t as
          = TYPE_ADDR_SPACE (TREE_TYPE (TREE_TYPE (TREE_OPERAND (exp, 0))));
        enum insn_code icode;
        unsigned int align;

        op0 = addr_for_mem_ref (exp, as, true);
        op0 = memory_address_addr_space (mode, op0, as);
        temp = gen_rtx_MEM (mode, op0);
        set_mem_attributes (temp, exp, 0);
        set_mem_addr_space (temp, as);
        align = get_object_alignment (exp);
        if (modifier != EXPAND_WRITE
            && modifier != EXPAND_MEMORY
            && mode != BLKmode
            && align < GET_MODE_ALIGNMENT (mode)
            /* If the target does not have special handling for unaligned
               loads of mode then it can use regular moves for them.  */
            && ((icode = optab_handler (movmisalign_optab, mode))
                != CODE_FOR_nothing))
          {
            struct expand_operand ops[2];

            /* We've already validated the memory, and we're creating a
               new pseudo destination.  The predicates really can't fail,
               nor can the generator.  */
            create_output_operand (&ops[0], NULL_RTX, mode);
            create_fixed_operand (&ops[1], temp);
            expand_insn (icode, 2, ops);
            temp = ops[0].value;
          }
        return temp;
      }

    case MEM_REF:
      {
        addr_space_t as
          = TYPE_ADDR_SPACE (TREE_TYPE (TREE_TYPE (TREE_OPERAND (exp, 0))));
        machine_mode address_mode;
        tree base = TREE_OPERAND (exp, 0);
        gimple def_stmt;
        enum insn_code icode;
        unsigned align;
        /* Handle expansion of non-aliased memory with non-BLKmode.  That
           might end up in a register.  */
        if (mem_ref_refers_to_non_mem_p (exp))
          {
            HOST_WIDE_INT offset = mem_ref_offset (exp).to_short_addr ();
            base = TREE_OPERAND (base, 0);
            if (offset == 0
                && tree_fits_uhwi_p (TYPE_SIZE (type))
                && (GET_MODE_BITSIZE (DECL_MODE (base))
                    == tree_to_uhwi (TYPE_SIZE (type))))
              return expand_expr (build1 (VIEW_CONVERT_EXPR, type, base),
                                  target, tmode, modifier);
            if (TYPE_MODE (type) == BLKmode)
              {
                temp = assign_stack_temp (DECL_MODE (base),
                                          GET_MODE_SIZE (DECL_MODE (base)));
                store_expr (base, temp, 0, false);
                temp = adjust_address (temp, BLKmode, offset);
                set_mem_size (temp, int_size_in_bytes (type));
                return temp;
              }
            exp = build3 (BIT_FIELD_REF, type, base, TYPE_SIZE (type),
                          bitsize_int (offset * BITS_PER_UNIT));
            return expand_expr (exp, target, tmode, modifier);
          }
        address_mode = targetm.addr_space.address_mode (as);
        base = TREE_OPERAND (exp, 0);
        if ((def_stmt = get_def_for_expr (base, BIT_AND_EXPR)))
          {
            tree mask = gimple_assign_rhs2 (def_stmt);
            base = build2 (BIT_AND_EXPR, TREE_TYPE (base),
                           gimple_assign_rhs1 (def_stmt), mask);
            TREE_OPERAND (exp, 0) = base;
          }
        align = get_object_alignment (exp);
        op0 = expand_expr (base, NULL_RTX, VOIDmode, EXPAND_SUM);
        op0 = memory_address_addr_space (mode, op0, as);
        if (!integer_zerop (TREE_OPERAND (exp, 1)))
          {
            rtx off = immed_wide_int_const (mem_ref_offset (exp), address_mode);
            op0 = simplify_gen_binary (PLUS, address_mode, op0, off);
            op0 = memory_address_addr_space (mode, op0, as);
          }
        temp = gen_rtx_MEM (mode, op0);
        set_mem_attributes (temp, exp, 0);
        set_mem_addr_space (temp, as);
        if (TREE_THIS_VOLATILE (exp))
          MEM_VOLATILE_P (temp) = 1;
        if (modifier != EXPAND_WRITE
            && modifier != EXPAND_MEMORY
            && !inner_reference_p
            && mode != BLKmode
            && align < GET_MODE_ALIGNMENT (mode))
          {
            if ((icode = optab_handler (movmisalign_optab, mode))
                != CODE_FOR_nothing)
              {
                struct expand_operand ops[2];

                /* We've already validated the memory, and we're creating a
                   new pseudo destination.  The predicates really can't fail,
                   nor can the generator.  */
                create_output_operand (&ops[0], NULL_RTX, mode);
                create_fixed_operand (&ops[1], temp);
                expand_insn (icode, 2, ops);
                temp = ops[0].value;
              }
            else if (SLOW_UNALIGNED_ACCESS (mode, align))
              temp = extract_bit_field (temp, GET_MODE_BITSIZE (mode),
                                        0, TYPE_UNSIGNED (TREE_TYPE (exp)),
                                        (modifier == EXPAND_STACK_PARM
                                         ? NULL_RTX : target),
                                        mode, mode);
          }
        return temp;
      }

    case ARRAY_REF:

      {
        tree array = treeop0;
        tree index = treeop1;
        tree init;

        /* Fold an expression like: "foo"[2].
           This is not done in fold so it won't happen inside &.
           Don't fold if this is for wide characters since it's too
           difficult to do correctly and this is a very rare case.  */

        if (modifier != EXPAND_CONST_ADDRESS
            && modifier != EXPAND_INITIALIZER
            && modifier != EXPAND_MEMORY)
          {
            tree t = fold_read_from_constant_string (exp);

            if (t)
              return expand_expr (t, target, tmode, modifier);
          }

        /* If this is a constant index into a constant array,
           just get the value from the array.  Handle both the cases when
           we have an explicit constructor and when our operand is a variable
           that was declared const.  */

        if (modifier != EXPAND_CONST_ADDRESS
            && modifier != EXPAND_INITIALIZER
            && modifier != EXPAND_MEMORY
            && TREE_CODE (array) == CONSTRUCTOR
            && ! TREE_SIDE_EFFECTS (array)
            && TREE_CODE (index) == INTEGER_CST)
          {
            unsigned HOST_WIDE_INT ix;
            tree field, value;

            FOR_EACH_CONSTRUCTOR_ELT (CONSTRUCTOR_ELTS (array), ix,
                                      field, value)
              if (tree_int_cst_equal (field, index))
                {
                  if (!TREE_SIDE_EFFECTS (value))
                    return expand_expr (fold (value), target, tmode, modifier);
                  break;
                }
          }

        else if (optimize >= 1
                 && modifier != EXPAND_CONST_ADDRESS
                 && modifier != EXPAND_INITIALIZER
                 && modifier != EXPAND_MEMORY
                 && TREE_READONLY (array) && ! TREE_SIDE_EFFECTS (array)
                 && TREE_CODE (index) == INTEGER_CST
                 && (TREE_CODE (array) == VAR_DECL
                     || TREE_CODE (array) == CONST_DECL)
                 && (init = ctor_for_folding (array)) != error_mark_node)
          {
            if (init == NULL_TREE)
              {
                tree value = build_zero_cst (type);
                if (TREE_CODE (value) == CONSTRUCTOR)
                  {
                    /* If VALUE is a CONSTRUCTOR, this optimization is only
                       useful if this doesn't store the CONSTRUCTOR into
                       memory.  If it does, it is more efficient to just
                       load the data from the array directly.  */
                    rtx ret = expand_constructor (value, target,
                                                  modifier, true);
                    if (ret == NULL_RTX)
                      value = NULL_TREE;
                  }

                if (value)
                  return expand_expr (value, target, tmode, modifier);
              }
            else if (TREE_CODE (init) == CONSTRUCTOR)
              {
                unsigned HOST_WIDE_INT ix;
                tree field, value;

                FOR_EACH_CONSTRUCTOR_ELT (CONSTRUCTOR_ELTS (init), ix,
                                          field, value)
                  if (tree_int_cst_equal (field, index))
                    {
                      if (TREE_SIDE_EFFECTS (value))
                        break;

                      if (TREE_CODE (value) == CONSTRUCTOR)
                        {
                          /* If VALUE is a CONSTRUCTOR, this
                             optimization is only useful if
                             this doesn't store the CONSTRUCTOR
                             into memory.  If it does, it is more
                             efficient to just load the data from
                             the array directly.  */
                          rtx ret = expand_constructor (value, target,
                                                        modifier, true);
                          if (ret == NULL_RTX)
                            break;
                        }

                      return
                        expand_expr (fold (value), target, tmode, modifier);
                    }
              }
            else if (TREE_CODE (init) == STRING_CST)
              {
                tree low_bound = array_ref_low_bound (exp);
                tree index1 = fold_convert_loc (loc, sizetype, treeop1);

                /* Optimize the special case of a zero lower bound.

                   We convert the lower bound to sizetype to avoid problems
                   with constant folding.  E.g. suppose the lower bound is
                   1 and its mode is QI.  Without the conversion
                      (ARRAY + (INDEX - (unsigned char)1))
                   becomes
                      (ARRAY + (-(unsigned char)1) + INDEX)
                   which becomes
                      (ARRAY + 255 + INDEX).  Oops!  */
                if (!integer_zerop (low_bound))
                  index1 = size_diffop_loc (loc, index1,
                                            fold_convert_loc (loc, sizetype,
                                                              low_bound));

                if (compare_tree_int (index1, TREE_STRING_LENGTH (init)) < 0)
                  {
                    tree type = TREE_TYPE (TREE_TYPE (init));
                    machine_mode mode = TYPE_MODE (type);

                    if (GET_MODE_CLASS (mode) == MODE_INT
                        && GET_MODE_SIZE (mode) == 1)
                      return gen_int_mode (TREE_STRING_POINTER (init)
                                           [TREE_INT_CST_LOW (index1)],
                                           mode);
                  }
              }
          }
      }
      goto normal_inner_ref;

    case COMPONENT_REF:
      /* If the operand is a CONSTRUCTOR, we can just extract the
         appropriate field if it is present.  */
      if (TREE_CODE (treeop0) == CONSTRUCTOR)
        {
          unsigned HOST_WIDE_INT idx;
          tree field, value;

          FOR_EACH_CONSTRUCTOR_ELT (CONSTRUCTOR_ELTS (treeop0),
                                    idx, field, value)
            if (field == treeop1
                /* We can normally use the value of the field in the
                   CONSTRUCTOR.  However, if this is a bitfield in
                   an integral mode that we can fit in a HOST_WIDE_INT,
                   we must mask only the number of bits in the bitfield,
                   since this is done implicitly by the constructor.  If
                   the bitfield does not meet either of those conditions,
                   we can't do this optimization.  */
                && (! DECL_BIT_FIELD (field)
                    || ((GET_MODE_CLASS (DECL_MODE (field)) == MODE_INT)
                        && (GET_MODE_PRECISION (DECL_MODE (field))
                            <= HOST_BITS_PER_WIDE_INT))))
              {
                if (DECL_BIT_FIELD (field)
                    && modifier == EXPAND_STACK_PARM)
                  target = 0;
                op0 = expand_expr (value, target, tmode, modifier);
                if (DECL_BIT_FIELD (field))
                  {
                    HOST_WIDE_INT bitsize = TREE_INT_CST_LOW (DECL_SIZE (field));
                    machine_mode imode = TYPE_MODE (TREE_TYPE (field));

                    if (TYPE_UNSIGNED (TREE_TYPE (field)))
                      {
                        op1 = gen_int_mode (((HOST_WIDE_INT) 1 << bitsize) - 1,
                                            imode);
                        op0 = expand_and (imode, op0, op1, target);
                      }
                    else
                      {
                        int count = GET_MODE_PRECISION (imode) - bitsize;

                        op0 = expand_shift (LSHIFT_EXPR, imode, op0, count,
                                            target, 0);
                        op0 = expand_shift (RSHIFT_EXPR, imode, op0, count,
                                            target, 0);
                      }
                  }

                return op0;
              }
        }
      goto normal_inner_ref;

    case BIT_FIELD_REF:
    case ARRAY_RANGE_REF:
    normal_inner_ref:
      {
        machine_mode mode1, mode2;
        HOST_WIDE_INT bitsize, bitpos;
        tree offset;
        int volatilep = 0, must_force_mem;
        tree tem = get_inner_reference (exp, &bitsize, &bitpos, &offset,
                                        &mode1, &unsignedp, &volatilep, true);
        rtx orig_op0, memloc;
        bool mem_attrs_from_type = false;

        /* If we got back the original object, something is wrong.  Perhaps
           we are evaluating an expression too early.  In any event, don't
           infinitely recurse.  */
        gcc_assert (tem != exp);

        /* If TEM's type is a union of variable size, pass TARGET to the inner
           computation, since it will need a temporary and TARGET is known
           to have to do.  This occurs in unchecked conversion in Ada.  */
        orig_op0 = op0
          = expand_expr_real (tem,
                              (TREE_CODE (TREE_TYPE (tem)) == UNION_TYPE
                               && COMPLETE_TYPE_P (TREE_TYPE (tem))
                               && (TREE_CODE (TYPE_SIZE (TREE_TYPE (tem)))
                                   != INTEGER_CST)
                               && modifier != EXPAND_STACK_PARM
                               ? target : NULL_RTX),
                              VOIDmode,
                              modifier == EXPAND_SUM ? EXPAND_NORMAL : modifier,
                              NULL, true);

        /* If the field has a mode, we want to access it in the
           field's mode, not the computed mode.
           If a MEM has VOIDmode (external with incomplete type),
           use BLKmode for it instead.  */
        if (MEM_P (op0))
          {
            if (mode1 != VOIDmode)
              op0 = adjust_address (op0, mode1, 0);
            else if (GET_MODE (op0) == VOIDmode)
              op0 = adjust_address (op0, BLKmode, 0);
          }

        mode2
          = CONSTANT_P (op0) ? TYPE_MODE (TREE_TYPE (tem)) : GET_MODE (op0);

        /* If we have either an offset, a BLKmode result, or a reference
           outside the underlying object, we must force it to memory.
           Such a case can occur in Ada if we have unchecked conversion
           of an expression from a scalar type to an aggregate type or
           for an ARRAY_RANGE_REF whose type is BLKmode, or if we were
           passed a partially uninitialized object or a view-conversion
           to a larger size.  */
        must_force_mem = (offset
                          || mode1 == BLKmode
                          || bitpos + bitsize > GET_MODE_BITSIZE (mode2));

        /* Handle CONCAT first.  */
        if (GET_CODE (op0) == CONCAT && !must_force_mem)
          {
            if (bitpos == 0
                && bitsize == GET_MODE_BITSIZE (GET_MODE (op0)))
              return op0;
            if (bitpos == 0
                && bitsize == GET_MODE_BITSIZE (GET_MODE (XEXP (op0, 0)))
                && bitsize)
              {
                op0 = XEXP (op0, 0);
                mode2 = GET_MODE (op0);
              }
            else if (bitpos == GET_MODE_BITSIZE (GET_MODE (XEXP (op0, 0)))
                     && bitsize == GET_MODE_BITSIZE (GET_MODE (XEXP (op0, 1)))
                     && bitpos
                     && bitsize)
              {
                op0 = XEXP (op0, 1);
                bitpos = 0;
                mode2 = GET_MODE (op0);
              }
            else
              /* Otherwise force into memory.  */
              must_force_mem = 1;
          }

        /* If this is a constant, put it in a register if it is a legitimate
           constant and we don't need a memory reference.  */
        if (CONSTANT_P (op0)
            && mode2 != BLKmode
            && targetm.legitimate_constant_p (mode2, op0)
            && !must_force_mem)
          op0 = force_reg (mode2, op0);

        /* Otherwise, if this is a constant, try to force it to the constant
           pool.  Note that back-ends, e.g. MIPS, may refuse to do so if it
           is a legitimate constant.  */
        else if (CONSTANT_P (op0) && (memloc = force_const_mem (mode2, op0)))
          op0 = validize_mem (memloc);

        /* Otherwise, if this is a constant or the object is not in memory
           and need be, put it there.  */
        else if (CONSTANT_P (op0) || (!MEM_P (op0) && must_force_mem))
          {
            memloc = assign_temp (TREE_TYPE (tem), 1, 1);
            emit_move_insn (memloc, op0);
            op0 = memloc;
            mem_attrs_from_type = true;
          }

        if (offset)
          {
            machine_mode address_mode;
            rtx offset_rtx = expand_expr (offset, NULL_RTX, VOIDmode,
                                          EXPAND_SUM);

            gcc_assert (MEM_P (op0));

            address_mode = get_address_mode (op0);
            if (GET_MODE (offset_rtx) != address_mode)
              offset_rtx = convert_to_mode (address_mode, offset_rtx, 0);

            /* See the comment in expand_assignment for the rationale.  */
            if (mode1 != VOIDmode
                && bitpos != 0
                && bitsize > 0
                && (bitpos % bitsize) == 0
                && (bitsize % GET_MODE_ALIGNMENT (mode1)) == 0
                && MEM_ALIGN (op0) >= GET_MODE_ALIGNMENT (mode1))
              {
                op0 = adjust_address (op0, mode1, bitpos / BITS_PER_UNIT);
                bitpos = 0;
              }

            op0 = offset_address (op0, offset_rtx,
                                  highest_pow2_factor (offset));
          }

        /* If OFFSET is making OP0 more aligned than BIGGEST_ALIGNMENT,
           record its alignment as BIGGEST_ALIGNMENT.  */
        if (MEM_P (op0) && bitpos == 0 && offset != 0
            && is_aligning_offset (offset, tem))
          set_mem_align (op0, BIGGEST_ALIGNMENT);

        /* Don't forget about volatility even if this is a bitfield.  */
        if (MEM_P (op0) && volatilep && ! MEM_VOLATILE_P (op0))
          {
            if (op0 == orig_op0)
              op0 = copy_rtx (op0);

            MEM_VOLATILE_P (op0) = 1;
          }

        /* In cases where an aligned union has an unaligned object
           as a field, we might be extracting a BLKmode value from
           an integer-mode (e.g., SImode) object.  Handle this case
           by doing the extract into an object as wide as the field
           (which we know to be the width of a basic mode), then
           storing into memory, and changing the mode to BLKmode.  */
        if (mode1 == VOIDmode
            || REG_P (op0) || GET_CODE (op0) == SUBREG
            || (mode1 != BLKmode && ! direct_load[(int) mode1]
                && GET_MODE_CLASS (mode) != MODE_COMPLEX_INT
                && GET_MODE_CLASS (mode) != MODE_COMPLEX_FLOAT
                && modifier != EXPAND_CONST_ADDRESS
                && modifier != EXPAND_INITIALIZER
                && modifier != EXPAND_MEMORY)
            /* If the bitfield is volatile and the bitsize
               is narrower than the access size of the bitfield,
               we need to extract bitfields from the access.  */
            || (volatilep && TREE_CODE (exp) == COMPONENT_REF
                && DECL_BIT_FIELD_TYPE (TREE_OPERAND (exp, 1))
                && mode1 != BLKmode
                && bitsize < GET_MODE_SIZE (mode1) * BITS_PER_UNIT)
            /* If the field isn't aligned enough to fetch as a memref,
               fetch it as a bit field.  */
            || (mode1 != BLKmode
                && (((TYPE_ALIGN (TREE_TYPE (tem)) < GET_MODE_ALIGNMENT (mode)
                      || (bitpos % GET_MODE_ALIGNMENT (mode) != 0)
                      || (MEM_P (op0)
                          && (MEM_ALIGN (op0) < GET_MODE_ALIGNMENT (mode1)
                              || (bitpos % GET_MODE_ALIGNMENT (mode1) != 0))))
                     && modifier != EXPAND_MEMORY
                     && ((modifier == EXPAND_CONST_ADDRESS
                          || modifier == EXPAND_INITIALIZER)
                         ? STRICT_ALIGNMENT
                         : SLOW_UNALIGNED_ACCESS (mode1, MEM_ALIGN (op0))))
                    || (bitpos % BITS_PER_UNIT != 0)))
            /* If the type and the field are a constant size and the
               size of the type isn't the same size as the bitfield,
               we must use bitfield operations.  */
            || (bitsize >= 0
                && TYPE_SIZE (TREE_TYPE (exp))
                && TREE_CODE (TYPE_SIZE (TREE_TYPE (exp))) == INTEGER_CST
                && 0 != compare_tree_int (TYPE_SIZE (TREE_TYPE (exp)),
                                          bitsize)))
          {
            machine_mode ext_mode = mode;

            if (ext_mode == BLKmode
                && ! (target != 0 && MEM_P (op0)
                      && MEM_P (target)
                      && bitpos % BITS_PER_UNIT == 0))
              ext_mode = mode_for_size (bitsize, MODE_INT, 1);

            if (ext_mode == BLKmode)
              {
                if (target == 0)
                  target = assign_temp (type, 1, 1);

                /* ??? Unlike the similar test a few lines below, this one is
                   very likely obsolete.  */
                if (bitsize == 0)
                  return target;

                /* In this case, BITPOS must start at a byte boundary and
                   TARGET, if specified, must be a MEM.  */
                gcc_assert (MEM_P (op0)
                            && (!target || MEM_P (target))
                            && !(bitpos % BITS_PER_UNIT));

                emit_block_move (target,
                                 adjust_address (op0, VOIDmode,
                                                 bitpos / BITS_PER_UNIT),
                                 GEN_INT ((bitsize + BITS_PER_UNIT - 1)
                                          / BITS_PER_UNIT),
                                 (modifier == EXPAND_STACK_PARM
                                  ? BLOCK_OP_CALL_PARM : BLOCK_OP_NORMAL));

                return target;
              }

            /* If we have nothing to extract, the result will be 0 for targets
               with SHIFT_COUNT_TRUNCATED == 0 and garbage otherwise.  Always
               return 0 for the sake of consistency, as reading a zero-sized
               bitfield is valid in Ada and the value is fully specified.  */
            if (bitsize == 0)
              return const0_rtx;

            op0 = validize_mem (op0);

            if (MEM_P (op0) && REG_P (XEXP (op0, 0)))
              mark_reg_pointer (XEXP (op0, 0), MEM_ALIGN (op0));

            op0 = extract_bit_field (op0, bitsize, bitpos, unsignedp,
                                     (modifier == EXPAND_STACK_PARM
                                      ? NULL_RTX : target),
                                     ext_mode, ext_mode);

            /* If the result is a record type and BITSIZE is narrower than
               the mode of OP0, an integral mode, and this is a big endian
               machine, we must put the field into the high-order bits.  */
            if (TREE_CODE (type) == RECORD_TYPE && BYTES_BIG_ENDIAN
                && GET_MODE_CLASS (GET_MODE (op0)) == MODE_INT
                && bitsize < (HOST_WIDE_INT) GET_MODE_BITSIZE (GET_MODE (op0)))
              op0 = expand_shift (LSHIFT_EXPR, GET_MODE (op0), op0,
                                  GET_MODE_BITSIZE (GET_MODE (op0))
                                  - bitsize, op0, 1);

            /* If the result type is BLKmode, store the data into a temporary
               of the appropriate type, but with the mode corresponding to the
               mode for the data we have (op0's mode).  */
            if (mode == BLKmode)
              {
                rtx new_rtx
                  = assign_stack_temp_for_type (ext_mode,
                                                GET_MODE_BITSIZE (ext_mode),
                                                type);
                emit_move_insn (new_rtx, op0);
                op0 = copy_rtx (new_rtx);
                PUT_MODE (op0, BLKmode);
              }

            return op0;
          }

        /* If the result is BLKmode, use that to access the object
           now as well.  */
        if (mode == BLKmode)
          mode1 = BLKmode;

        /* Get a reference to just this component.  */
        if (modifier == EXPAND_CONST_ADDRESS
            || modifier == EXPAND_SUM || modifier == EXPAND_INITIALIZER)
          op0 = adjust_address_nv (op0, mode1, bitpos / BITS_PER_UNIT);
        else
          op0 = adjust_address (op0, mode1, bitpos / BITS_PER_UNIT);

        if (op0 == orig_op0)
          op0 = copy_rtx (op0);

        /* If op0 is a temporary because of forcing to memory, pass only the
           type to set_mem_attributes so that the original expression is never
           marked as ADDRESSABLE through MEM_EXPR of the temporary.  */
        if (mem_attrs_from_type)
          set_mem_attributes (op0, type, 0);
        else
          set_mem_attributes (op0, exp, 0);

        if (REG_P (XEXP (op0, 0)))
          mark_reg_pointer (XEXP (op0, 0), MEM_ALIGN (op0));

        MEM_VOLATILE_P (op0) |= volatilep;
        if (mode == mode1 || mode1 == BLKmode || mode1 == tmode
            || modifier == EXPAND_CONST_ADDRESS
            || modifier == EXPAND_INITIALIZER)
          return op0;

        if (target == 0)
          target = gen_reg_rtx (tmode != VOIDmode ? tmode : mode);

        convert_move (target, op0, unsignedp);
        return target;
      }

    case OBJ_TYPE_REF:
      return expand_expr (OBJ_TYPE_REF_EXPR (exp), target, tmode, modifier);

    case CALL_EXPR:
      /* All valid uses of __builtin_va_arg_pack () are removed during
         inlining.  */
      if (CALL_EXPR_VA_ARG_PACK (exp))
        error ("%Kinvalid use of %<__builtin_va_arg_pack ()%>", exp);
      {
        tree fndecl = get_callee_fndecl (exp), attr;

        if (fndecl
            && (attr = lookup_attribute ("error",
                                         DECL_ATTRIBUTES (fndecl))) != NULL)
          error ("%Kcall to %qs declared with attribute error: %s",
                 exp, identifier_to_locale (lang_hooks.decl_printable_name (fndecl, 1)),
                 TREE_STRING_POINTER (TREE_VALUE (TREE_VALUE (attr))));
        if (fndecl
            && (attr = lookup_attribute ("warning",
                                         DECL_ATTRIBUTES (fndecl))) != NULL)
          warning_at (tree_nonartificial_location (exp),
                      0, "%Kcall to %qs declared with attribute warning: %s",
                      exp, identifier_to_locale (lang_hooks.decl_printable_name (fndecl, 1)),
                      TREE_STRING_POINTER (TREE_VALUE (TREE_VALUE (attr))));

        /* Check for a built-in function.  */
        if (fndecl && DECL_BUILT_IN (fndecl))
          {
            gcc_assert (DECL_BUILT_IN_CLASS (fndecl) != BUILT_IN_FRONTEND);
            return expand_builtin (exp, target, subtarget, tmode, ignore);
          }
      }
      return expand_call (exp, target, ignore);

    case VIEW_CONVERT_EXPR:
      op0 = NULL_RTX;

      /* If we are converting to BLKmode, try to avoid an intermediate
         temporary by fetching an inner memory reference.  */
      if (mode == BLKmode
          && TREE_CODE (TYPE_SIZE (type)) == INTEGER_CST
          && TYPE_MODE (TREE_TYPE (treeop0)) != BLKmode
          && handled_component_p (treeop0))
      {
        machine_mode mode1;
        HOST_WIDE_INT bitsize, bitpos;
        tree offset;
        int unsignedp;
        int volatilep = 0;
        tree tem
          = get_inner_reference (treeop0, &bitsize, &bitpos,
                                 &offset, &mode1, &unsignedp, &volatilep,
                                 true);
        rtx orig_op0;

        /* ??? We should work harder and deal with non-zero offsets.  */
        if (!offset
            && (bitpos % BITS_PER_UNIT) == 0
            && bitsize >= 0
            && compare_tree_int (TYPE_SIZE (type), bitsize) == 0)
          {
            /* See the normal_inner_ref case for the rationale.  */
            orig_op0
              = expand_expr_real (tem,
                                  (TREE_CODE (TREE_TYPE (tem)) == UNION_TYPE
                                   && (TREE_CODE (TYPE_SIZE (TREE_TYPE (tem)))
                                       != INTEGER_CST)
                                   && modifier != EXPAND_STACK_PARM
                                   ? target : NULL_RTX),
                                  VOIDmode,
                                  modifier == EXPAND_SUM ? EXPAND_NORMAL : modifier,
                                  NULL, true);

            if (MEM_P (orig_op0))
              {
                op0 = orig_op0;

                /* Get a reference to just this component.  */
                if (modifier == EXPAND_CONST_ADDRESS
                    || modifier == EXPAND_SUM
                    || modifier == EXPAND_INITIALIZER)
                  op0 = adjust_address_nv (op0, mode, bitpos / BITS_PER_UNIT);
                else
                  op0 = adjust_address (op0, mode, bitpos / BITS_PER_UNIT);

                if (op0 == orig_op0)
                  op0 = copy_rtx (op0);

                set_mem_attributes (op0, treeop0, 0);
                if (REG_P (XEXP (op0, 0)))
                  mark_reg_pointer (XEXP (op0, 0), MEM_ALIGN (op0));

                MEM_VOLATILE_P (op0) |= volatilep;
              }
          }
      }

      if (!op0)
        op0 = expand_expr_real (treeop0, NULL_RTX, VOIDmode, modifier,
                                NULL, inner_reference_p);

      /* If the input and output modes are both the same, we are done.  */
      if (mode == GET_MODE (op0))
        ;
      /* If neither mode is BLKmode, and both modes are the same size
         then we can use gen_lowpart.  */
      else if (mode != BLKmode && GET_MODE (op0) != BLKmode
               && (GET_MODE_PRECISION (mode)
                   == GET_MODE_PRECISION (GET_MODE (op0)))
               && !COMPLEX_MODE_P (GET_MODE (op0)))
        {
          if (GET_CODE (op0) == SUBREG)
            op0 = force_reg (GET_MODE (op0), op0);
          temp = gen_lowpart_common (mode, op0);
          if (temp)
            op0 = temp;
          else
            {
              if (!REG_P (op0) && !MEM_P (op0))
                op0 = force_reg (GET_MODE (op0), op0);
              op0 = gen_lowpart (mode, op0);
            }
        }
      /* If both types are integral, convert from one mode to the other.  */
      else if (INTEGRAL_TYPE_P (type) && INTEGRAL_TYPE_P (TREE_TYPE (treeop0)))
        op0 = convert_modes (mode, GET_MODE (op0), op0,
                             TYPE_UNSIGNED (TREE_TYPE (treeop0)));
      /* If the output type is a bit-field type, do an extraction.  */
      else if (reduce_bit_field)
        return extract_bit_field (op0, TYPE_PRECISION (type), 0,
                                  TYPE_UNSIGNED (type), NULL_RTX,
                                  mode, mode);
      /* As a last resort, spill op0 to memory, and reload it in a
         different mode.  */
      else if (!MEM_P (op0))
        {
          /* If the operand is not a MEM, force it into memory.  Since we
             are going to be changing the mode of the MEM, don't call
             force_const_mem for constants because we don't allow pool
             constants to change mode.  */
          tree inner_type = TREE_TYPE (treeop0);

          gcc_assert (!TREE_ADDRESSABLE (exp));

          if (target == 0 || GET_MODE (target) != TYPE_MODE (inner_type))
            target
              = assign_stack_temp_for_type
                (TYPE_MODE (inner_type),
                 GET_MODE_SIZE (TYPE_MODE (inner_type)), inner_type);

          emit_move_insn (target, op0);
          op0 = target;
        }

      /* If OP0 is (now) a MEM, we need to deal with alignment issues.  If the
         output type is such that the operand is known to be aligned, indicate
         that it is.  Otherwise, we need only be concerned about alignment for
         non-BLKmode results.  */
      if (MEM_P (op0))
        {
          enum insn_code icode;

          if (TYPE_ALIGN_OK (type))
            {
              /* ??? Copying the MEM without substantially changing it might
                 run afoul of the code handling volatile memory references in
                 store_expr, which assumes that TARGET is returned unmodified
                 if it has been used.  */
              op0 = copy_rtx (op0);
              set_mem_align (op0, MAX (MEM_ALIGN (op0), TYPE_ALIGN (type)));
            }
          else if (modifier != EXPAND_WRITE
                   && modifier != EXPAND_MEMORY
                   && !inner_reference_p
                   && mode != BLKmode
                   && MEM_ALIGN (op0) < GET_MODE_ALIGNMENT (mode))
            {
              /* If the target does have special handling for unaligned
                 loads of mode then use them.  */
              if ((icode = optab_handler (movmisalign_optab, mode))
                  != CODE_FOR_nothing)
                {
                  rtx reg, insn;

                  op0 = adjust_address (op0, mode, 0);
                  /* We've already validated the memory, and we're creating a
                     new pseudo destination.  The predicates really can't
                     fail.  */
                  reg = gen_reg_rtx (mode);

                  /* Nor can the insn generator.  */
                  insn = GEN_FCN (icode) (reg, op0);
                  emit_insn (insn);
                  return reg;
                }
              else if (STRICT_ALIGNMENT)
                {
                  tree inner_type = TREE_TYPE (treeop0);
                  HOST_WIDE_INT temp_size
                    = MAX (int_size_in_bytes (inner_type),
                           (HOST_WIDE_INT) GET_MODE_SIZE (mode));
                  rtx new_rtx
                    = assign_stack_temp_for_type (mode, temp_size, type);
                  rtx new_with_op0_mode
                    = adjust_address (new_rtx, GET_MODE (op0), 0);

                  gcc_assert (!TREE_ADDRESSABLE (exp));

                  if (GET_MODE (op0) == BLKmode)
                    emit_block_move (new_with_op0_mode, op0,
                                     GEN_INT (GET_MODE_SIZE (mode)),
                                     (modifier == EXPAND_STACK_PARM
                                      ? BLOCK_OP_CALL_PARM : BLOCK_OP_NORMAL));
                  else
                    emit_move_insn (new_with_op0_mode, op0);

                  op0 = new_rtx;
                }
            }

          op0 = adjust_address (op0, mode, 0);
        }

      return op0;

    case MODIFY_EXPR:
      {
        tree lhs = treeop0;
        tree rhs = treeop1;
        gcc_assert (ignore);

        /* Check for |= or &= of a bitfield of size one into another bitfield
           of size 1.  In this case, (unless we need the result of the
           assignment) we can do this more efficiently with a
           test followed by an assignment, if necessary.

           ??? At this point, we can't get a BIT_FIELD_REF here.  But if
           things change so we do, this code should be enhanced to
           support it.  */
        if (TREE_CODE (lhs) == COMPONENT_REF
            && (TREE_CODE (rhs) == BIT_IOR_EXPR
                || TREE_CODE (rhs) == BIT_AND_EXPR)
            && TREE_OPERAND (rhs, 0) == lhs
            && TREE_CODE (TREE_OPERAND (rhs, 1)) == COMPONENT_REF
            && integer_onep (DECL_SIZE (TREE_OPERAND (lhs, 1)))
            && integer_onep (DECL_SIZE (TREE_OPERAND (TREE_OPERAND (rhs, 1), 1))))
          {
            rtx_code_label *label = gen_label_rtx ();
            int value = TREE_CODE (rhs) == BIT_IOR_EXPR;
            do_jump (TREE_OPERAND (rhs, 1),
                     value ? label : 0,
                     value ? 0 : label, -1);
            expand_assignment (lhs, build_int_cst (TREE_TYPE (rhs), value),
                               false);
            do_pending_stack_adjust ();
            emit_label (label);
            return const0_rtx;
          }

        expand_assignment (lhs, rhs, false);
        return const0_rtx;
      }

    case ADDR_EXPR:
      return expand_expr_addr_expr (exp, target, tmode, modifier);

    case REALPART_EXPR:
      op0 = expand_normal (treeop0);
      return read_complex_part (op0, false);

    case IMAGPART_EXPR:
      op0 = expand_normal (treeop0);
      return read_complex_part (op0, true);

    case RETURN_EXPR:
    case LABEL_EXPR:
    case GOTO_EXPR:
    case SWITCH_EXPR:
    case ASM_EXPR:
      /* Expanded in cfgexpand.c.  */
      gcc_unreachable ();

    case TRY_CATCH_EXPR:
    case CATCH_EXPR:
    case EH_FILTER_EXPR:
    case TRY_FINALLY_EXPR:
      /* Lowered by tree-eh.c.  */
      gcc_unreachable ();

    case WITH_CLEANUP_EXPR:
    case CLEANUP_POINT_EXPR:
    case TARGET_EXPR:
    case CASE_LABEL_EXPR:
    case VA_ARG_EXPR:
    case BIND_EXPR:
    case INIT_EXPR:
    case CONJ_EXPR:
    case COMPOUND_EXPR:
    case PREINCREMENT_EXPR:
    case PREDECREMENT_EXPR:
    case POSTINCREMENT_EXPR:
    case POSTDECREMENT_EXPR:
    case LOOP_EXPR:
    case EXIT_EXPR:
    case COMPOUND_LITERAL_EXPR:
      /* Lowered by gimplify.c.  */
      gcc_unreachable ();

    case FDESC_EXPR:
      /* Function descriptors are not valid except for as
         initialization constants, and should not be expanded.  */
      gcc_unreachable ();

    case WITH_SIZE_EXPR:
      /* WITH_SIZE_EXPR expands to its first argument.  The caller should
         have pulled out the size to use in whatever context it needed.  */
      return expand_expr_real (treeop0, original_target, tmode,
                               modifier, alt_rtl, inner_reference_p);

    default:
      return expand_expr_real_2 (&ops, target, tmode, modifier);
    }
}
\f
/* Subroutine of above: reduce EXP to the precision of TYPE (in the
   signedness of TYPE), possibly returning the result in TARGET.  */
static rtx
reduce_to_bit_field_precision (rtx exp, rtx target, tree type)
{
  HOST_WIDE_INT prec = TYPE_PRECISION (type);
  if (target && GET_MODE (target) != GET_MODE (exp))
    target = 0;
  /* For constant values, reduce using build_int_cst_type. */
  if (CONST_INT_P (exp))
    {
      HOST_WIDE_INT value = INTVAL (exp);
      tree t = build_int_cst_type (type, value);
      return expand_expr (t, target, VOIDmode, EXPAND_NORMAL);
    }
  else if (TYPE_UNSIGNED (type))
    {
      machine_mode mode = GET_MODE (exp);
      rtx mask = immed_wide_int_const
        (wi::mask (prec, false, GET_MODE_PRECISION (mode)), mode);
      return expand_and (mode, exp, mask, target);
    }
  else
    {
      int count = GET_MODE_PRECISION (GET_MODE (exp)) - prec;
      exp = expand_shift (LSHIFT_EXPR, GET_MODE (exp),
                          exp, count, target, 0);
      return expand_shift (RSHIFT_EXPR, GET_MODE (exp),
                           exp, count, target, 0);
    }
}
\f
/* Subroutine of above: returns 1 if OFFSET corresponds to an offset that
   when applied to the address of EXP produces an address known to be
   aligned more than BIGGEST_ALIGNMENT.  */

static int
is_aligning_offset (const_tree offset, const_tree exp)
{
  /* Strip off any conversions.  */
  while (CONVERT_EXPR_P (offset))
    offset = TREE_OPERAND (offset, 0);

  /* We must now have a BIT_AND_EXPR with a constant that is one less than
     power of 2 and which is larger than BIGGEST_ALIGNMENT.  */
  if (TREE_CODE (offset) != BIT_AND_EXPR
      || !tree_fits_uhwi_p (TREE_OPERAND (offset, 1))
      || compare_tree_int (TREE_OPERAND (offset, 1),
                           BIGGEST_ALIGNMENT / BITS_PER_UNIT) <= 0
      || exact_log2 (tree_to_uhwi (TREE_OPERAND (offset, 1)) + 1) < 0)
    return 0;

  /* Look at the first operand of BIT_AND_EXPR and strip any conversion.
     It must be NEGATE_EXPR.  Then strip any more conversions.  */
  offset = TREE_OPERAND (offset, 0);
  while (CONVERT_EXPR_P (offset))
    offset = TREE_OPERAND (offset, 0);

  if (TREE_CODE (offset) != NEGATE_EXPR)
    return 0;

  offset = TREE_OPERAND (offset, 0);
  while (CONVERT_EXPR_P (offset))
    offset = TREE_OPERAND (offset, 0);

  /* This must now be the address of EXP.  */
  return TREE_CODE (offset) == ADDR_EXPR && TREE_OPERAND (offset, 0) == exp;
}
\f
/* Return the tree node if an ARG corresponds to a string constant or zero
   if it doesn't.  If we return nonzero, set *PTR_OFFSET to the offset
   in bytes within the string that ARG is accessing.  The type of the
   offset will be `sizetype'.  */

tree
string_constant (tree arg, tree *ptr_offset)
{
  tree array, offset, lower_bound;
  STRIP_NOPS (arg);

  if (TREE_CODE (arg) == ADDR_EXPR)
    {
      if (TREE_CODE (TREE_OPERAND (arg, 0)) == STRING_CST)
        {
          *ptr_offset = size_zero_node;
          return TREE_OPERAND (arg, 0);
        }
      else if (TREE_CODE (TREE_OPERAND (arg, 0)) == VAR_DECL)
        {
          array = TREE_OPERAND (arg, 0);
          offset = size_zero_node;
        }
      else if (TREE_CODE (TREE_OPERAND (arg, 0)) == ARRAY_REF)
        {
          array = TREE_OPERAND (TREE_OPERAND (arg, 0), 0);
          offset = TREE_OPERAND (TREE_OPERAND (arg, 0), 1);
          if (TREE_CODE (array) != STRING_CST
              && TREE_CODE (array) != VAR_DECL)
            return 0;

          /* Check if the array has a nonzero lower bound.  */
          lower_bound = array_ref_low_bound (TREE_OPERAND (arg, 0));
          if (!integer_zerop (lower_bound))
            {
              /* If the offset and base aren't both constants, return 0.  */
              if (TREE_CODE (lower_bound) != INTEGER_CST)
                return 0;
              if (TREE_CODE (offset) != INTEGER_CST)
                return 0;
              /* Adjust offset by the lower bound.  */
              offset = size_diffop (fold_convert (sizetype, offset),
                                    fold_convert (sizetype, lower_bound));
            }
        }
      else if (TREE_CODE (TREE_OPERAND (arg, 0)) == MEM_REF)
        {
          array = TREE_OPERAND (TREE_OPERAND (arg, 0), 0);
          offset = TREE_OPERAND (TREE_OPERAND (arg, 0), 1);
          if (TREE_CODE (array) != ADDR_EXPR)
            return 0;
          array = TREE_OPERAND (array, 0);
          if (TREE_CODE (array) != STRING_CST
              && TREE_CODE (array) != VAR_DECL)
            return 0;
        }
      else
        return 0;
    }
  else if (TREE_CODE (arg) == PLUS_EXPR || TREE_CODE (arg) == POINTER_PLUS_EXPR)
    {
      tree arg0 = TREE_OPERAND (arg, 0);
      tree arg1 = TREE_OPERAND (arg, 1);

      STRIP_NOPS (arg0);
      STRIP_NOPS (arg1);

      if (TREE_CODE (arg0) == ADDR_EXPR
          && (TREE_CODE (TREE_OPERAND (arg0, 0)) == STRING_CST
              || TREE_CODE (TREE_OPERAND (arg0, 0)) == VAR_DECL))
        {
          array = TREE_OPERAND (arg0, 0);
          offset = arg1;
        }
      else if (TREE_CODE (arg1) == ADDR_EXPR
               && (TREE_CODE (TREE_OPERAND (arg1, 0)) == STRING_CST
                   || TREE_CODE (TREE_OPERAND (arg1, 0)) == VAR_DECL))
        {
          array = TREE_OPERAND (arg1, 0);
          offset = arg0;
        }
      else
        return 0;
    }
  else
    return 0;

  if (TREE_CODE (array) == STRING_CST)
    {
      *ptr_offset = fold_convert (sizetype, offset);
      return array;
    }
  else if (TREE_CODE (array) == VAR_DECL
           || TREE_CODE (array) == CONST_DECL)
    {
      int length;
      tree init = ctor_for_folding (array);

      /* Variables initialized to string literals can be handled too.  */
      if (init == error_mark_node
          || !init
          || TREE_CODE (init) != STRING_CST)
        return 0;

      /* Avoid const char foo[4] = "abcde";  */
      if (DECL_SIZE_UNIT (array) == NULL_TREE
          || TREE_CODE (DECL_SIZE_UNIT (array)) != INTEGER_CST
          || (length = TREE_STRING_LENGTH (init)) <= 0
          || compare_tree_int (DECL_SIZE_UNIT (array), length) < 0)
        return 0;

      /* If variable is bigger than the string literal, OFFSET must be constant
         and inside of the bounds of the string literal.  */
      offset = fold_convert (sizetype, offset);
      if (compare_tree_int (DECL_SIZE_UNIT (array), length) > 0
          && (! tree_fits_uhwi_p (offset)
              || compare_tree_int (offset, length) >= 0))
        return 0;

      *ptr_offset = offset;
      return init;
    }

  return 0;
}
\f
/* Generate code to calculate OPS, and exploded expression
   using a store-flag instruction and return an rtx for the result.
   OPS reflects a comparison.

   If TARGET is nonzero, store the result there if convenient.

   Return zero if there is no suitable set-flag instruction
   available on this machine.

   Once expand_expr has been called on the arguments of the comparison,
   we are committed to doing the store flag, since it is not safe to
   re-evaluate the expression.  We emit the store-flag insn by calling
   emit_store_flag, but only expand the arguments if we have a reason
   to believe that emit_store_flag will be successful.  If we think that
   it will, but it isn't, we have to simulate the store-flag with a
   set/jump/set sequence.  */

static rtx
do_store_flag (sepops ops, rtx target, machine_mode mode)
{
  enum rtx_code code;
  tree arg0, arg1, type;
  tree tem;
  machine_mode operand_mode;
  int unsignedp;
  rtx op0, op1;
  rtx subtarget = target;
  location_t loc = ops->location;

  arg0 = ops->op0;
  arg1 = ops->op1;

  /* Don't crash if the comparison was erroneous.  */
  if (arg0 == error_mark_node || arg1 == error_mark_node)
    return const0_rtx;

  type = TREE_TYPE (arg0);
  operand_mode = TYPE_MODE (type);
  unsignedp = TYPE_UNSIGNED (type);

  /* We won't bother with BLKmode store-flag operations because it would mean
     passing a lot of information to emit_store_flag.  */
  if (operand_mode == BLKmode)
    return 0;

  /* We won't bother with store-flag operations involving function pointers
     when function pointers must be canonicalized before comparisons.  */
#ifdef HAVE_canonicalize_funcptr_for_compare
  if (HAVE_canonicalize_funcptr_for_compare
      && ((TREE_CODE (TREE_TYPE (arg0)) == POINTER_TYPE
           && (TREE_CODE (TREE_TYPE (TREE_TYPE (arg0)))
               == FUNCTION_TYPE))
          || (TREE_CODE (TREE_TYPE (arg1)) == POINTER_TYPE
              && (TREE_CODE (TREE_TYPE (TREE_TYPE (arg1)))
                  == FUNCTION_TYPE))))
    return 0;
#endif

  STRIP_NOPS (arg0);
  STRIP_NOPS (arg1);
  
  /* For vector typed comparisons emit code to generate the desired
     all-ones or all-zeros mask.  Conveniently use the VEC_COND_EXPR
     expander for this.  */
  if (TREE_CODE (ops->type) == VECTOR_TYPE)
    {
      tree ifexp = build2 (ops->code, ops->type, arg0, arg1);
      tree if_true = constant_boolean_node (true, ops->type);
      tree if_false = constant_boolean_node (false, ops->type);
      return expand_vec_cond_expr (ops->type, ifexp, if_true, if_false, target);
    }

  /* Get the rtx comparison code to use.  We know that EXP is a comparison
     operation of some type.  Some comparisons against 1 and -1 can be
     converted to comparisons with zero.  Do so here so that the tests
     below will be aware that we have a comparison with zero.   These
     tests will not catch constants in the first operand, but constants
     are rarely passed as the first operand.  */

  switch (ops->code)
    {
    case EQ_EXPR:
      code = EQ;
      break;
    case NE_EXPR:
      code = NE;
      break;
    case LT_EXPR:
      if (integer_onep (arg1))
        arg1 = integer_zero_node, code = unsignedp ? LEU : LE;
      else
        code = unsignedp ? LTU : LT;
      break;
    case LE_EXPR:
      if (! unsignedp && integer_all_onesp (arg1))
        arg1 = integer_zero_node, code = LT;
      else
        code = unsignedp ? LEU : LE;
      break;
    case GT_EXPR:
      if (! unsignedp && integer_all_onesp (arg1))
        arg1 = integer_zero_node, code = GE;
      else
        code = unsignedp ? GTU : GT;
      break;
    case GE_EXPR:
      if (integer_onep (arg1))
        arg1 = integer_zero_node, code = unsignedp ? GTU : GT;
      else
        code = unsignedp ? GEU : GE;
      break;

    case UNORDERED_EXPR:
      code = UNORDERED;
      break;
    case ORDERED_EXPR:
      code = ORDERED;
      break;
    case UNLT_EXPR:
      code = UNLT;
      break;
    case UNLE_EXPR:
      code = UNLE;
      break;
    case UNGT_EXPR:
      code = UNGT;
      break;
    case UNGE_EXPR:
      code = UNGE;
      break;
    case UNEQ_EXPR:
      code = UNEQ;
      break;
    case LTGT_EXPR:
      code = LTGT;
      break;

    default:
      gcc_unreachable ();
    }

  /* Put a constant second.  */
  if (TREE_CODE (arg0) == REAL_CST || TREE_CODE (arg0) == INTEGER_CST
      || TREE_CODE (arg0) == FIXED_CST)
    {
      tem = arg0; arg0 = arg1; arg1 = tem;
      code = swap_condition (code);
    }

  /* If this is an equality or inequality test of a single bit, we can
     do this by shifting the bit being tested to the low-order bit and
     masking the result with the constant 1.  If the condition was EQ,
     we xor it with 1.  This does not require an scc insn and is faster
     than an scc insn even if we have it.

     The code to make this transformation was moved into fold_single_bit_test,
     so we just call into the folder and expand its result.  */

  if ((code == NE || code == EQ)
      && integer_zerop (arg1)
      && (TYPE_PRECISION (ops->type) != 1 || TYPE_UNSIGNED (ops->type)))
    {
      gimple srcstmt = get_def_for_expr (arg0, BIT_AND_EXPR);
      if (srcstmt
          && integer_pow2p (gimple_assign_rhs2 (srcstmt)))
        {
          enum tree_code tcode = code == NE ? NE_EXPR : EQ_EXPR;
          tree type = lang_hooks.types.type_for_mode (mode, unsignedp);
          tree temp = fold_build2_loc (loc, BIT_AND_EXPR, TREE_TYPE (arg1),
                                       gimple_assign_rhs1 (srcstmt),
                                       gimple_assign_rhs2 (srcstmt));
          temp = fold_single_bit_test (loc, tcode, temp, arg1, type);
          if (temp)
            return expand_expr (temp, target, VOIDmode, EXPAND_NORMAL);
        }
    }

  if (! get_subtarget (target)
      || GET_MODE (subtarget) != operand_mode)
    subtarget = 0;

  expand_operands (arg0, arg1, subtarget, &op0, &op1, EXPAND_NORMAL);

  if (target == 0)
    target = gen_reg_rtx (mode);

  /* Try a cstore if possible.  */
  return emit_store_flag_force (target, code, op0, op1,
                                operand_mode, unsignedp,
                                (TYPE_PRECISION (ops->type) == 1
                                 && !TYPE_UNSIGNED (ops->type)) ? -1 : 1);
}
\f

/* Stubs in case we haven't got a casesi insn.  */
#ifndef HAVE_casesi
# define HAVE_casesi 0
# define gen_casesi(a, b, c, d, e) (0)
# define CODE_FOR_casesi CODE_FOR_nothing
#endif

/* Attempt to generate a casesi instruction.  Returns 1 if successful,
   0 otherwise (i.e. if there is no casesi instruction).

   DEFAULT_PROBABILITY is the probability of jumping to the default
   label.  */
int
try_casesi (tree index_type, tree index_expr, tree minval, tree range,
            rtx table_label, rtx default_label, rtx fallback_label,
            int default_probability)
{
  struct expand_operand ops[5];
  machine_mode index_mode = SImode;
  rtx op1, op2, index;

  if (! HAVE_casesi)
    return 0;

  /* Convert the index to SImode.  */
  if (GET_MODE_BITSIZE (TYPE_MODE (index_type)) > GET_MODE_BITSIZE (index_mode))
    {
      machine_mode omode = TYPE_MODE (index_type);
      rtx rangertx = expand_normal (range);

      /* We must handle the endpoints in the original mode.  */
      index_expr = build2 (MINUS_EXPR, index_type,
                           index_expr, minval);
      minval = integer_zero_node;
      index = expand_normal (index_expr);
      if (default_label)
        emit_cmp_and_jump_insns (rangertx, index, LTU, NULL_RTX,
                                 omode, 1, default_label,
                                 default_probability);
      /* Now we can safely truncate.  */
      index = convert_to_mode (index_mode, index, 0);
    }
  else
    {
      if (TYPE_MODE (index_type) != index_mode)
        {
          index_type = lang_hooks.types.type_for_mode (index_mode, 0);
          index_expr = fold_convert (index_type, index_expr);
        }

      index = expand_normal (index_expr);
    }

  do_pending_stack_adjust ();

  op1 = expand_normal (minval);
  op2 = expand_normal (range);

  create_input_operand (&ops[0], index, index_mode);
  create_convert_operand_from_type (&ops[1], op1, TREE_TYPE (minval));
  create_convert_operand_from_type (&ops[2], op2, TREE_TYPE (range));
  create_fixed_operand (&ops[3], table_label);
  create_fixed_operand (&ops[4], (default_label
                                  ? default_label
                                  : fallback_label));
  expand_jump_insn (CODE_FOR_casesi, 5, ops);
  return 1;
}

/* Attempt to generate a tablejump instruction; same concept.  */
#ifndef HAVE_tablejump
#define HAVE_tablejump 0
#define gen_tablejump(x, y) (0)
#endif

/* Subroutine of the next function.

   INDEX is the value being switched on, with the lowest value
   in the table already subtracted.
   MODE is its expected mode (needed if INDEX is constant).
   RANGE is the length of the jump table.
   TABLE_LABEL is a CODE_LABEL rtx for the table itself.

   DEFAULT_LABEL is a CODE_LABEL rtx to jump to if the
   index value is out of range.
   DEFAULT_PROBABILITY is the probability of jumping to
   the default label.  */

static void
do_tablejump (rtx index, machine_mode mode, rtx range, rtx table_label,
              rtx default_label, int default_probability)
{
  rtx temp, vector;

  if (INTVAL (range) > cfun->cfg->max_jumptable_ents)
    cfun->cfg->max_jumptable_ents = INTVAL (range);

  /* Do an unsigned comparison (in the proper mode) between the index
     expression and the value which represents the length of the range.
     Since we just finished subtracting the lower bound of the range
     from the index expression, this comparison allows us to simultaneously
     check that the original index expression value is both greater than
     or equal to the minimum value of the range and less than or equal to
     the maximum value of the range.  */

  if (default_label)
    emit_cmp_and_jump_insns (index, range, GTU, NULL_RTX, mode, 1,
                             default_label, default_probability);


  /* If index is in range, it must fit in Pmode.
     Convert to Pmode so we can index with it.  */
  if (mode != Pmode)
    index = convert_to_mode (Pmode, index, 1);

  /* Don't let a MEM slip through, because then INDEX that comes
     out of PIC_CASE_VECTOR_ADDRESS won't be a valid address,
     and break_out_memory_refs will go to work on it and mess it up.  */
#ifdef PIC_CASE_VECTOR_ADDRESS
  if (flag_pic && !REG_P (index))
    index = copy_to_mode_reg (Pmode, index);
#endif

  /* ??? The only correct use of CASE_VECTOR_MODE is the one inside the
     GET_MODE_SIZE, because this indicates how large insns are.  The other
     uses should all be Pmode, because they are addresses.  This code
     could fail if addresses and insns are not the same size.  */
  index = simplify_gen_binary (MULT, Pmode, index,
                               gen_int_mode (GET_MODE_SIZE (CASE_VECTOR_MODE),
                                             Pmode));
  index = simplify_gen_binary (PLUS, Pmode, index,
                               gen_rtx_LABEL_REF (Pmode, table_label));

#ifdef PIC_CASE_VECTOR_ADDRESS
  if (flag_pic)
    index = PIC_CASE_VECTOR_ADDRESS (index);
  else
#endif
    index = memory_address (CASE_VECTOR_MODE, index);
  temp = gen_reg_rtx (CASE_VECTOR_MODE);
  vector = gen_const_mem (CASE_VECTOR_MODE, index);
  convert_move (temp, vector, 0);

  emit_jump_insn (gen_tablejump (temp, table_label));

  /* If we are generating PIC code or if the table is PC-relative, the
     table and JUMP_INSN must be adjacent, so don't output a BARRIER.  */
  if (! CASE_VECTOR_PC_RELATIVE && ! flag_pic)
    emit_barrier ();
}

int
try_tablejump (tree index_type, tree index_expr, tree minval, tree range,
               rtx table_label, rtx default_label, int default_probability)
{
  rtx index;

  if (! HAVE_tablejump)
    return 0;

  index_expr = fold_build2 (MINUS_EXPR, index_type,
                            fold_convert (index_type, index_expr),
                            fold_convert (index_type, minval));
  index = expand_normal (index_expr);
  do_pending_stack_adjust ();

  do_tablejump (index, TYPE_MODE (index_type),
                convert_modes (TYPE_MODE (index_type),
                               TYPE_MODE (TREE_TYPE (range)),
                               expand_normal (range),
                               TYPE_UNSIGNED (TREE_TYPE (range))),
                table_label, default_label, default_probability);
  return 1;
}

/* Return a CONST_VECTOR rtx for a VECTOR_CST tree.  */
static rtx
const_vector_from_tree (tree exp)
{
  rtvec v;
  unsigned i;
  int units;
  tree elt;
  machine_mode inner, mode;

  mode = TYPE_MODE (TREE_TYPE (exp));

  if (initializer_zerop (exp))
    return CONST0_RTX (mode);

  units = GET_MODE_NUNITS (mode);
  inner = GET_MODE_INNER (mode);

  v = rtvec_alloc (units);

  for (i = 0; i < VECTOR_CST_NELTS (exp); ++i)
    {
      elt = VECTOR_CST_ELT (exp, i);

      if (TREE_CODE (elt) == REAL_CST)
        RTVEC_ELT (v, i) = CONST_DOUBLE_FROM_REAL_VALUE (TREE_REAL_CST (elt),
                                                         inner);
      else if (TREE_CODE (elt) == FIXED_CST)
        RTVEC_ELT (v, i) = CONST_FIXED_FROM_FIXED_VALUE (TREE_FIXED_CST (elt),
                                                         inner);
      else
        RTVEC_ELT (v, i) = immed_wide_int_const (elt, inner);
    }

  return gen_rtx_CONST_VECTOR (mode, v);
}

/* Build a decl for a personality function given a language prefix.  */

tree
build_personality_function (const char *lang)
{
  const char *unwind_and_version;
  tree decl, type;
  char *name;

  switch (targetm_common.except_unwind_info (&global_options))
    {
    case UI_NONE:
      return NULL;
    case UI_SJLJ:
      unwind_and_version = "_sj0";
      break;
    case UI_DWARF2:
    case UI_TARGET:
      unwind_and_version = "_v0";
      break;
    case UI_SEH:
      unwind_and_version = "_seh0";
      break;
    default:
      gcc_unreachable ();
    }

  name = ACONCAT (("__", lang, "_personality", unwind_and_version, NULL));

  type = build_function_type_list (integer_type_node, integer_type_node,
                                   long_long_unsigned_type_node,
                                   ptr_type_node, ptr_type_node, NULL_TREE);
  decl = build_decl (UNKNOWN_LOCATION, FUNCTION_DECL,
                     get_identifier (name), type);
  DECL_ARTIFICIAL (decl) = 1;
  DECL_EXTERNAL (decl) = 1;
  TREE_PUBLIC (decl) = 1;

  /* Zap the nonsensical SYMBOL_REF_DECL for this.  What we're left with
     are the flags assigned by targetm.encode_section_info.  */
  SET_SYMBOL_REF_DECL (XEXP (DECL_RTL (decl), 0), NULL);

  return decl;
}

/* Extracts the personality function of DECL and returns the corresponding
   libfunc.  */

rtx
get_personality_function (tree decl)
{
  tree personality = DECL_FUNCTION_PERSONALITY (decl);
  enum eh_personality_kind pk;

  pk = function_needs_eh_personality (DECL_STRUCT_FUNCTION (decl));
  if (pk == eh_personality_none)
    return NULL;

  if (!personality
      && pk == eh_personality_any)
    personality = lang_hooks.eh_personality ();

  if (pk == eh_personality_lang)
    gcc_assert (personality != NULL_TREE);

  return XEXP (DECL_RTL (personality), 0);
}

#include "gt-expr.h"