2013-10-01 Saurabh Verma <saurabh.verma@codito.com>

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

/* Subroutines used by or related to instruction recognition.
   Copyright (C) 1987-2013 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 "rtl-error.h"
#include "tm_p.h"
#include "insn-config.h"
#include "insn-attr.h"
#include "hard-reg-set.h"
#include "recog.h"
#include "regs.h"
#include "addresses.h"
#include "expr.h"
#include "function.h"
#include "flags.h"
#include "basic-block.h"
#include "reload.h"
#include "target.h"
#include "tree-pass.h"
#include "df.h"
#include "insn-codes.h"

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

#ifndef STACK_POP_CODE
#ifdef STACK_GROWS_DOWNWARD
#define STACK_POP_CODE POST_INC
#else
#define STACK_POP_CODE POST_DEC
#endif
#endif

static void validate_replace_rtx_1 (rtx *, rtx, rtx, rtx, bool);
static void validate_replace_src_1 (rtx *, void *);
static rtx split_insn (rtx);

/* Nonzero means allow operands to be volatile.
   This should be 0 if you are generating rtl, such as if you are calling
   the functions in optabs.c and expmed.c (most of the time).
   This should be 1 if all valid insns need to be recognized,
   such as in reginfo.c and final.c and reload.c.

   init_recog and init_recog_no_volatile are responsible for setting this.  */

int volatile_ok;

struct recog_data_d recog_data;

/* Contains a vector of operand_alternative structures for every operand.
   Set up by preprocess_constraints.  */
struct operand_alternative recog_op_alt[MAX_RECOG_OPERANDS][MAX_RECOG_ALTERNATIVES];

/* On return from `constrain_operands', indicate which alternative
   was satisfied.  */

int which_alternative;

/* Nonzero after end of reload pass.
   Set to 1 or 0 by toplev.c.
   Controls the significance of (SUBREG (MEM)).  */

int reload_completed;

/* Nonzero after thread_prologue_and_epilogue_insns has run.  */
int epilogue_completed;

/* Initialize data used by the function `recog'.
   This must be called once in the compilation of a function
   before any insn recognition may be done in the function.  */

void
init_recog_no_volatile (void)
{
  volatile_ok = 0;
}

void
init_recog (void)
{
  volatile_ok = 1;
}

\f
/* Return true if labels in asm operands BODY are LABEL_REFs.  */

static bool
asm_labels_ok (rtx body)
{
  rtx asmop;
  int i;

  asmop = extract_asm_operands (body);
  if (asmop == NULL_RTX)
    return true;

  for (i = 0; i < ASM_OPERANDS_LABEL_LENGTH (asmop); i++)
    if (GET_CODE (ASM_OPERANDS_LABEL (asmop, i)) != LABEL_REF)
      return false;

  return true;
}

/* Check that X is an insn-body for an `asm' with operands
   and that the operands mentioned in it are legitimate.  */

int
check_asm_operands (rtx x)
{
  int noperands;
  rtx *operands;
  const char **constraints;
  int i;

  if (!asm_labels_ok (x))
    return 0;

  /* Post-reload, be more strict with things.  */
  if (reload_completed)
    {
      /* ??? Doh!  We've not got the wrapping insn.  Cook one up.  */
      extract_insn (make_insn_raw (x));
      constrain_operands (1);
      return which_alternative >= 0;
    }

  noperands = asm_noperands (x);
  if (noperands < 0)
    return 0;
  if (noperands == 0)
    return 1;

  operands = XALLOCAVEC (rtx, noperands);
  constraints = XALLOCAVEC (const char *, noperands);

  decode_asm_operands (x, operands, NULL, constraints, NULL, NULL);

  for (i = 0; i < noperands; i++)
    {
      const char *c = constraints[i];
      if (c[0] == '%')
        c++;
      if (! asm_operand_ok (operands[i], c, constraints))
        return 0;
    }

  return 1;
}
\f
/* Static data for the next two routines.  */

typedef struct change_t
{
  rtx object;
  int old_code;
  rtx *loc;
  rtx old;
  bool unshare;
} change_t;

static change_t *changes;
static int changes_allocated;

static int num_changes = 0;

/* Validate a proposed change to OBJECT.  LOC is the location in the rtl
   at which NEW_RTX will be placed.  If OBJECT is zero, no validation is done,
   the change is simply made.

   Two types of objects are supported:  If OBJECT is a MEM, memory_address_p
   will be called with the address and mode as parameters.  If OBJECT is
   an INSN, CALL_INSN, or JUMP_INSN, the insn will be re-recognized with
   the change in place.

   IN_GROUP is nonzero if this is part of a group of changes that must be
   performed as a group.  In that case, the changes will be stored.  The
   function `apply_change_group' will validate and apply the changes.

   If IN_GROUP is zero, this is a single change.  Try to recognize the insn
   or validate the memory reference with the change applied.  If the result
   is not valid for the machine, suppress the change and return zero.
   Otherwise, perform the change and return 1.  */

static bool
validate_change_1 (rtx object, rtx *loc, rtx new_rtx, bool in_group, bool unshare)
{
  rtx old = *loc;

  if (old == new_rtx || rtx_equal_p (old, new_rtx))
    return 1;

  gcc_assert (in_group != 0 || num_changes == 0);

  *loc = new_rtx;

  /* Save the information describing this change.  */
  if (num_changes >= changes_allocated)
    {
      if (changes_allocated == 0)
        /* This value allows for repeated substitutions inside complex
           indexed addresses, or changes in up to 5 insns.  */
        changes_allocated = MAX_RECOG_OPERANDS * 5;
      else
        changes_allocated *= 2;

      changes = XRESIZEVEC (change_t, changes, changes_allocated);
    }

  changes[num_changes].object = object;
  changes[num_changes].loc = loc;
  changes[num_changes].old = old;
  changes[num_changes].unshare = unshare;

  if (object && !MEM_P (object))
    {
      /* Set INSN_CODE to force rerecognition of insn.  Save old code in
         case invalid.  */
      changes[num_changes].old_code = INSN_CODE (object);
      INSN_CODE (object) = -1;
    }

  num_changes++;

  /* If we are making a group of changes, return 1.  Otherwise, validate the
     change group we made.  */

  if (in_group)
    return 1;
  else
    return apply_change_group ();
}

/* Wrapper for validate_change_1 without the UNSHARE argument defaulting
   UNSHARE to false.  */

bool
validate_change (rtx object, rtx *loc, rtx new_rtx, bool in_group)
{
  return validate_change_1 (object, loc, new_rtx, in_group, false);
}

/* Wrapper for validate_change_1 without the UNSHARE argument defaulting
   UNSHARE to true.  */

bool
validate_unshare_change (rtx object, rtx *loc, rtx new_rtx, bool in_group)
{
  return validate_change_1 (object, loc, new_rtx, in_group, true);
}


/* Keep X canonicalized if some changes have made it non-canonical; only
   modifies the operands of X, not (for example) its code.  Simplifications
   are not the job of this routine.

   Return true if anything was changed.  */
bool
canonicalize_change_group (rtx insn, rtx x)
{
  if (COMMUTATIVE_P (x)
      && swap_commutative_operands_p (XEXP (x, 0), XEXP (x, 1)))
    {
      /* Oops, the caller has made X no longer canonical.
         Let's redo the changes in the correct order.  */
      rtx tem = XEXP (x, 0);
      validate_unshare_change (insn, &XEXP (x, 0), XEXP (x, 1), 1);
      validate_unshare_change (insn, &XEXP (x, 1), tem, 1);
      return true;
    }
  else
    return false;
}


/* This subroutine of apply_change_group verifies whether the changes to INSN
   were valid; i.e. whether INSN can still be recognized.

   If IN_GROUP is true clobbers which have to be added in order to
   match the instructions will be added to the current change group.
   Otherwise the changes will take effect immediately.  */

int
insn_invalid_p (rtx insn, bool in_group)
{
  rtx pat = PATTERN (insn);
  int num_clobbers = 0;
  /* If we are before reload and the pattern is a SET, see if we can add
     clobbers.  */
  int icode = recog (pat, insn,
                     (GET_CODE (pat) == SET
                      && ! reload_completed && ! reload_in_progress)
                     ? &num_clobbers : 0);
  int is_asm = icode < 0 && asm_noperands (PATTERN (insn)) >= 0;


  /* If this is an asm and the operand aren't legal, then fail.  Likewise if
     this is not an asm and the insn wasn't recognized.  */
  if ((is_asm && ! check_asm_operands (PATTERN (insn)))
      || (!is_asm && icode < 0))
    return 1;

  /* If we have to add CLOBBERs, fail if we have to add ones that reference
     hard registers since our callers can't know if they are live or not.
     Otherwise, add them.  */
  if (num_clobbers > 0)
    {
      rtx newpat;

      if (added_clobbers_hard_reg_p (icode))
        return 1;

      newpat = gen_rtx_PARALLEL (VOIDmode, rtvec_alloc (num_clobbers + 1));
      XVECEXP (newpat, 0, 0) = pat;
      add_clobbers (newpat, icode);
      if (in_group)
        validate_change (insn, &PATTERN (insn), newpat, 1);
      else
        PATTERN (insn) = pat = newpat;
    }

  /* After reload, verify that all constraints are satisfied.  */
  if (reload_completed)
    {
      extract_insn (insn);

      if (! constrain_operands (1))
        return 1;
    }

  INSN_CODE (insn) = icode;
  return 0;
}

/* Return number of changes made and not validated yet.  */
int
num_changes_pending (void)
{
  return num_changes;
}

/* Tentatively apply the changes numbered NUM and up.
   Return 1 if all changes are valid, zero otherwise.  */

int
verify_changes (int num)
{
  int i;
  rtx last_validated = NULL_RTX;

  /* The changes have been applied and all INSN_CODEs have been reset to force
     rerecognition.

     The changes are valid if we aren't given an object, or if we are
     given a MEM and it still is a valid address, or if this is in insn
     and it is recognized.  In the latter case, if reload has completed,
     we also require that the operands meet the constraints for
     the insn.  */

  for (i = num; i < num_changes; i++)
    {
      rtx object = changes[i].object;

      /* If there is no object to test or if it is the same as the one we
         already tested, ignore it.  */
      if (object == 0 || object == last_validated)
        continue;

      if (MEM_P (object))
        {
          if (! memory_address_addr_space_p (GET_MODE (object),
                                             XEXP (object, 0),
                                             MEM_ADDR_SPACE (object)))
            break;
        }
      else if (/* changes[i].old might be zero, e.g. when putting a
               REG_FRAME_RELATED_EXPR into a previously empty list.  */
               changes[i].old
               && REG_P (changes[i].old)
               && asm_noperands (PATTERN (object)) > 0
               && REG_EXPR (changes[i].old) != NULL_TREE
               && DECL_ASSEMBLER_NAME_SET_P (REG_EXPR (changes[i].old))
               && DECL_REGISTER (REG_EXPR (changes[i].old)))
        {
          /* Don't allow changes of hard register operands to inline
             assemblies if they have been defined as register asm ("x").  */
          break;
        }
      else if (DEBUG_INSN_P (object))
        continue;
      else if (insn_invalid_p (object, true))
        {
          rtx pat = PATTERN (object);

          /* Perhaps we couldn't recognize the insn because there were
             extra CLOBBERs at the end.  If so, try to re-recognize
             without the last CLOBBER (later iterations will cause each of
             them to be eliminated, in turn).  But don't do this if we
             have an ASM_OPERAND.  */
          if (GET_CODE (pat) == PARALLEL
              && GET_CODE (XVECEXP (pat, 0, XVECLEN (pat, 0) - 1)) == CLOBBER
              && asm_noperands (PATTERN (object)) < 0)
            {
              rtx newpat;

              if (XVECLEN (pat, 0) == 2)
                newpat = XVECEXP (pat, 0, 0);
              else
                {
                  int j;

                  newpat
                    = gen_rtx_PARALLEL (VOIDmode,
                                        rtvec_alloc (XVECLEN (pat, 0) - 1));
                  for (j = 0; j < XVECLEN (newpat, 0); j++)
                    XVECEXP (newpat, 0, j) = XVECEXP (pat, 0, j);
                }

              /* Add a new change to this group to replace the pattern
                 with this new pattern.  Then consider this change
                 as having succeeded.  The change we added will
                 cause the entire call to fail if things remain invalid.

                 Note that this can lose if a later change than the one
                 we are processing specified &XVECEXP (PATTERN (object), 0, X)
                 but this shouldn't occur.  */

              validate_change (object, &PATTERN (object), newpat, 1);
              continue;
            }
          else if (GET_CODE (pat) == USE || GET_CODE (pat) == CLOBBER
                   || GET_CODE (pat) == VAR_LOCATION)
            /* If this insn is a CLOBBER or USE, it is always valid, but is
               never recognized.  */
            continue;
          else
            break;
        }
      last_validated = object;
    }

  return (i == num_changes);
}

/* A group of changes has previously been issued with validate_change
   and verified with verify_changes.  Call df_insn_rescan for each of
   the insn changed and clear num_changes.  */

void
confirm_change_group (void)
{
  int i;
  rtx last_object = NULL;

  for (i = 0; i < num_changes; i++)
    {
      rtx object = changes[i].object;

      if (changes[i].unshare)
        *changes[i].loc = copy_rtx (*changes[i].loc);

      /* Avoid unnecessary rescanning when multiple changes to same instruction
         are made.  */
      if (object)
        {
          if (object != last_object && last_object && INSN_P (last_object))
            df_insn_rescan (last_object);
          last_object = object;
        }
    }

  if (last_object && INSN_P (last_object))
    df_insn_rescan (last_object);
  num_changes = 0;
}

/* Apply a group of changes previously issued with `validate_change'.
   If all changes are valid, call confirm_change_group and return 1,
   otherwise, call cancel_changes and return 0.  */

int
apply_change_group (void)
{
  if (verify_changes (0))
    {
      confirm_change_group ();
      return 1;
    }
  else
    {
      cancel_changes (0);
      return 0;
    }
}


/* Return the number of changes so far in the current group.  */

int
num_validated_changes (void)
{
  return num_changes;
}

/* Retract the changes numbered NUM and up.  */

void
cancel_changes (int num)
{
  int i;

  /* Back out all the changes.  Do this in the opposite order in which
     they were made.  */
  for (i = num_changes - 1; i >= num; i--)
    {
      *changes[i].loc = changes[i].old;
      if (changes[i].object && !MEM_P (changes[i].object))
        INSN_CODE (changes[i].object) = changes[i].old_code;
    }
  num_changes = num;
}

/* Reduce conditional compilation elsewhere.  */
#ifndef HAVE_extv
#define HAVE_extv       0
#define CODE_FOR_extv   CODE_FOR_nothing
#endif
#ifndef HAVE_extzv
#define HAVE_extzv      0
#define CODE_FOR_extzv  CODE_FOR_nothing
#endif

/* A subroutine of validate_replace_rtx_1 that tries to simplify the resulting
   rtx.  */

static void
simplify_while_replacing (rtx *loc, rtx to, rtx object,
                          enum machine_mode op0_mode)
{
  rtx x = *loc;
  enum rtx_code code = GET_CODE (x);
  rtx new_rtx;

  if (SWAPPABLE_OPERANDS_P (x)
      && swap_commutative_operands_p (XEXP (x, 0), XEXP (x, 1)))
    {
      validate_unshare_change (object, loc,
                               gen_rtx_fmt_ee (COMMUTATIVE_ARITH_P (x) ? code
                                               : swap_condition (code),
                                               GET_MODE (x), XEXP (x, 1),
                                               XEXP (x, 0)), 1);
      x = *loc;
      code = GET_CODE (x);
    }

  switch (code)
    {
    case PLUS:
      /* If we have a PLUS whose second operand is now a CONST_INT, use
         simplify_gen_binary to try to simplify it.
         ??? We may want later to remove this, once simplification is
         separated from this function.  */
      if (CONST_INT_P (XEXP (x, 1)) && XEXP (x, 1) == to)
        validate_change (object, loc,
                         simplify_gen_binary
                         (PLUS, GET_MODE (x), XEXP (x, 0), XEXP (x, 1)), 1);
      break;
    case MINUS:
      if (CONST_SCALAR_INT_P (XEXP (x, 1)))
        validate_change (object, loc,
                         simplify_gen_binary
                         (PLUS, GET_MODE (x), XEXP (x, 0),
                          simplify_gen_unary (NEG,
                                              GET_MODE (x), XEXP (x, 1),
                                              GET_MODE (x))), 1);
      break;
    case ZERO_EXTEND:
    case SIGN_EXTEND:
      if (GET_MODE (XEXP (x, 0)) == VOIDmode)
        {
          new_rtx = simplify_gen_unary (code, GET_MODE (x), XEXP (x, 0),
                                    op0_mode);
          /* If any of the above failed, substitute in something that
             we know won't be recognized.  */
          if (!new_rtx)
            new_rtx = gen_rtx_CLOBBER (GET_MODE (x), const0_rtx);
          validate_change (object, loc, new_rtx, 1);
        }
      break;
    case SUBREG:
      /* All subregs possible to simplify should be simplified.  */
      new_rtx = simplify_subreg (GET_MODE (x), SUBREG_REG (x), op0_mode,
                             SUBREG_BYTE (x));

      /* Subregs of VOIDmode operands are incorrect.  */
      if (!new_rtx && GET_MODE (SUBREG_REG (x)) == VOIDmode)
        new_rtx = gen_rtx_CLOBBER (GET_MODE (x), const0_rtx);
      if (new_rtx)
        validate_change (object, loc, new_rtx, 1);
      break;
    case ZERO_EXTRACT:
    case SIGN_EXTRACT:
      /* If we are replacing a register with memory, try to change the memory
         to be the mode required for memory in extract operations (this isn't
         likely to be an insertion operation; if it was, nothing bad will
         happen, we might just fail in some cases).  */

      if (MEM_P (XEXP (x, 0))
          && CONST_INT_P (XEXP (x, 1))
          && CONST_INT_P (XEXP (x, 2))
          && !mode_dependent_address_p (XEXP (XEXP (x, 0), 0),
                                        MEM_ADDR_SPACE (XEXP (x, 0)))
          && !MEM_VOLATILE_P (XEXP (x, 0)))
        {
          enum machine_mode wanted_mode = VOIDmode;
          enum machine_mode is_mode = GET_MODE (XEXP (x, 0));
          int pos = INTVAL (XEXP (x, 2));

          if (GET_CODE (x) == ZERO_EXTRACT && HAVE_extzv)
            {
              wanted_mode = insn_data[CODE_FOR_extzv].operand[1].mode;
              if (wanted_mode == VOIDmode)
                wanted_mode = word_mode;
            }
          else if (GET_CODE (x) == SIGN_EXTRACT && HAVE_extv)
            {
              wanted_mode = insn_data[CODE_FOR_extv].operand[1].mode;
              if (wanted_mode == VOIDmode)
                wanted_mode = word_mode;
            }

          /* If we have a narrower mode, we can do something.  */
          if (wanted_mode != VOIDmode
              && GET_MODE_SIZE (wanted_mode) < GET_MODE_SIZE (is_mode))
            {
              int offset = pos / BITS_PER_UNIT;
              rtx newmem;

              /* If the bytes and bits are counted differently, we
                 must adjust the offset.  */
              if (BYTES_BIG_ENDIAN != BITS_BIG_ENDIAN)
                offset =
                  (GET_MODE_SIZE (is_mode) - GET_MODE_SIZE (wanted_mode) -
                   offset);

              gcc_assert (GET_MODE_PRECISION (wanted_mode)
                          == GET_MODE_BITSIZE (wanted_mode));
              pos %= GET_MODE_BITSIZE (wanted_mode);

              newmem = adjust_address_nv (XEXP (x, 0), wanted_mode, offset);

              validate_change (object, &XEXP (x, 2), GEN_INT (pos), 1);
              validate_change (object, &XEXP (x, 0), newmem, 1);
            }
        }

      break;

    default:
      break;
    }
}

/* Replace every occurrence of FROM in X with TO.  Mark each change with
   validate_change passing OBJECT.  */

static void
validate_replace_rtx_1 (rtx *loc, rtx from, rtx to, rtx object,
                        bool simplify)
{
  int i, j;
  const char *fmt;
  rtx x = *loc;
  enum rtx_code code;
  enum machine_mode op0_mode = VOIDmode;
  int prev_changes = num_changes;

  if (!x)
    return;

  code = GET_CODE (x);
  fmt = GET_RTX_FORMAT (code);
  if (fmt[0] == 'e')
    op0_mode = GET_MODE (XEXP (x, 0));

  /* X matches FROM if it is the same rtx or they are both referring to the
     same register in the same mode.  Avoid calling rtx_equal_p unless the
     operands look similar.  */

  if (x == from
      || (REG_P (x) && REG_P (from)
          && GET_MODE (x) == GET_MODE (from)
          && REGNO (x) == REGNO (from))
      || (GET_CODE (x) == GET_CODE (from) && GET_MODE (x) == GET_MODE (from)
          && rtx_equal_p (x, from)))
    {
      validate_unshare_change (object, loc, to, 1);
      return;
    }

  /* Call ourself recursively to perform the replacements.
     We must not replace inside already replaced expression, otherwise we
     get infinite recursion for replacements like (reg X)->(subreg (reg X))
     done by regmove, so we must special case shared ASM_OPERANDS.  */

  if (GET_CODE (x) == PARALLEL)
    {
      for (j = XVECLEN (x, 0) - 1; j >= 0; j--)
        {
          if (j && GET_CODE (XVECEXP (x, 0, j)) == SET
              && GET_CODE (SET_SRC (XVECEXP (x, 0, j))) == ASM_OPERANDS)
            {
              /* Verify that operands are really shared.  */
              gcc_assert (ASM_OPERANDS_INPUT_VEC (SET_SRC (XVECEXP (x, 0, 0)))
                          == ASM_OPERANDS_INPUT_VEC (SET_SRC (XVECEXP
                                                              (x, 0, j))));
              validate_replace_rtx_1 (&SET_DEST (XVECEXP (x, 0, j)),
                                      from, to, object, simplify);
            }
          else
            validate_replace_rtx_1 (&XVECEXP (x, 0, j), from, to, object,
                                    simplify);
        }
    }
  else
    for (i = GET_RTX_LENGTH (code) - 1; i >= 0; i--)
      {
        if (fmt[i] == 'e')
          validate_replace_rtx_1 (&XEXP (x, i), from, to, object, simplify);
        else if (fmt[i] == 'E')
          for (j = XVECLEN (x, i) - 1; j >= 0; j--)
            validate_replace_rtx_1 (&XVECEXP (x, i, j), from, to, object,
                                    simplify);
      }

  /* If we didn't substitute, there is nothing more to do.  */
  if (num_changes == prev_changes)
    return;

  /* Allow substituted expression to have different mode.  This is used by
     regmove to change mode of pseudo register.  */
  if (fmt[0] == 'e' && GET_MODE (XEXP (x, 0)) != VOIDmode)
    op0_mode = GET_MODE (XEXP (x, 0));

  /* Do changes needed to keep rtx consistent.  Don't do any other
     simplifications, as it is not our job.  */
  if (simplify)
    simplify_while_replacing (loc, to, object, op0_mode);
}

/* Try replacing every occurrence of FROM in subexpression LOC of INSN
   with TO.  After all changes have been made, validate by seeing
   if INSN is still valid.  */

int
validate_replace_rtx_subexp (rtx from, rtx to, rtx insn, rtx *loc)
{
  validate_replace_rtx_1 (loc, from, to, insn, true);
  return apply_change_group ();
}

/* Try replacing every occurrence of FROM in INSN with TO.  After all
   changes have been made, validate by seeing if INSN is still valid.  */

int
validate_replace_rtx (rtx from, rtx to, rtx insn)
{
  validate_replace_rtx_1 (&PATTERN (insn), from, to, insn, true);
  return apply_change_group ();
}

/* Try replacing every occurrence of FROM in WHERE with TO.  Assume that WHERE
   is a part of INSN.  After all changes have been made, validate by seeing if
   INSN is still valid.
   validate_replace_rtx (from, to, insn) is equivalent to
   validate_replace_rtx_part (from, to, &PATTERN (insn), insn).  */

int
validate_replace_rtx_part (rtx from, rtx to, rtx *where, rtx insn)
{
  validate_replace_rtx_1 (where, from, to, insn, true);
  return apply_change_group ();
}

/* Same as above, but do not simplify rtx afterwards.  */
int
validate_replace_rtx_part_nosimplify (rtx from, rtx to, rtx *where,
                                      rtx insn)
{
  validate_replace_rtx_1 (where, from, to, insn, false);
  return apply_change_group ();

}

/* Try replacing every occurrence of FROM in INSN with TO.  This also
   will replace in REG_EQUAL and REG_EQUIV notes.  */

void
validate_replace_rtx_group (rtx from, rtx to, rtx insn)
{
  rtx note;
  validate_replace_rtx_1 (&PATTERN (insn), from, to, insn, true);
  for (note = REG_NOTES (insn); note; note = XEXP (note, 1))
    if (REG_NOTE_KIND (note) == REG_EQUAL
        || REG_NOTE_KIND (note) == REG_EQUIV)
      validate_replace_rtx_1 (&XEXP (note, 0), from, to, insn, true);
}

/* Function called by note_uses to replace used subexpressions.  */
struct validate_replace_src_data
{
  rtx from;                     /* Old RTX */
  rtx to;                       /* New RTX */
  rtx insn;                     /* Insn in which substitution is occurring.  */
};

static void
validate_replace_src_1 (rtx *x, void *data)
{
  struct validate_replace_src_data *d
    = (struct validate_replace_src_data *) data;

  validate_replace_rtx_1 (x, d->from, d->to, d->insn, true);
}

/* Try replacing every occurrence of FROM in INSN with TO, avoiding
   SET_DESTs.  */

void
validate_replace_src_group (rtx from, rtx to, rtx insn)
{
  struct validate_replace_src_data d;

  d.from = from;
  d.to = to;
  d.insn = insn;
  note_uses (&PATTERN (insn), validate_replace_src_1, &d);
}

/* Try simplify INSN.
   Invoke simplify_rtx () on every SET_SRC and SET_DEST inside the INSN's
   pattern and return true if something was simplified.  */

bool
validate_simplify_insn (rtx insn)
{
  int i;
  rtx pat = NULL;
  rtx newpat = NULL;

  pat = PATTERN (insn);

  if (GET_CODE (pat) == SET)
    {
      newpat = simplify_rtx (SET_SRC (pat));
      if (newpat && !rtx_equal_p (SET_SRC (pat), newpat))
        validate_change (insn, &SET_SRC (pat), newpat, 1);
      newpat = simplify_rtx (SET_DEST (pat));
      if (newpat && !rtx_equal_p (SET_DEST (pat), newpat))
        validate_change (insn, &SET_DEST (pat), newpat, 1);
    }
  else if (GET_CODE (pat) == PARALLEL)
    for (i = 0; i < XVECLEN (pat, 0); i++)
      {
        rtx s = XVECEXP (pat, 0, i);

        if (GET_CODE (XVECEXP (pat, 0, i)) == SET)
          {
            newpat = simplify_rtx (SET_SRC (s));
            if (newpat && !rtx_equal_p (SET_SRC (s), newpat))
              validate_change (insn, &SET_SRC (s), newpat, 1);
            newpat = simplify_rtx (SET_DEST (s));
            if (newpat && !rtx_equal_p (SET_DEST (s), newpat))
              validate_change (insn, &SET_DEST (s), newpat, 1);
          }
      }
  return ((num_changes_pending () > 0) && (apply_change_group () > 0));
}
\f
#ifdef HAVE_cc0
/* Return 1 if the insn using CC0 set by INSN does not contain
   any ordered tests applied to the condition codes.
   EQ and NE tests do not count.  */

int
next_insn_tests_no_inequality (rtx insn)
{
  rtx next = next_cc0_user (insn);

  /* If there is no next insn, we have to take the conservative choice.  */
  if (next == 0)
    return 0;

  return (INSN_P (next)
          && ! inequality_comparisons_p (PATTERN (next)));
}
#endif
\f
/* Return 1 if OP is a valid general operand for machine mode MODE.
   This is either a register reference, a memory reference,
   or a constant.  In the case of a memory reference, the address
   is checked for general validity for the target machine.

   Register and memory references must have mode MODE in order to be valid,
   but some constants have no machine mode and are valid for any mode.

   If MODE is VOIDmode, OP is checked for validity for whatever mode
   it has.

   The main use of this function is as a predicate in match_operand
   expressions in the machine description.  */

int
general_operand (rtx op, enum machine_mode mode)
{
  enum rtx_code code = GET_CODE (op);

  if (mode == VOIDmode)
    mode = GET_MODE (op);

  /* Don't accept CONST_INT or anything similar
     if the caller wants something floating.  */
  if (GET_MODE (op) == VOIDmode && mode != VOIDmode
      && GET_MODE_CLASS (mode) != MODE_INT
      && GET_MODE_CLASS (mode) != MODE_PARTIAL_INT)
    return 0;

  if (CONST_INT_P (op)
      && mode != VOIDmode
      && trunc_int_for_mode (INTVAL (op), mode) != INTVAL (op))
    return 0;

  if (CONSTANT_P (op))
    return ((GET_MODE (op) == VOIDmode || GET_MODE (op) == mode
             || mode == VOIDmode)
            && (! flag_pic || LEGITIMATE_PIC_OPERAND_P (op))
            && targetm.legitimate_constant_p (mode == VOIDmode
                                              ? GET_MODE (op)
                                              : mode, op));

  /* Except for certain constants with VOIDmode, already checked for,
     OP's mode must match MODE if MODE specifies a mode.  */

  if (GET_MODE (op) != mode)
    return 0;

  if (code == SUBREG)
    {
      rtx sub = SUBREG_REG (op);

#ifdef INSN_SCHEDULING
      /* On machines that have insn scheduling, we want all memory
         reference to be explicit, so outlaw paradoxical SUBREGs.
         However, we must allow them after reload so that they can
         get cleaned up by cleanup_subreg_operands.  */
      if (!reload_completed && MEM_P (sub)
          && GET_MODE_SIZE (mode) > GET_MODE_SIZE (GET_MODE (sub)))
        return 0;
#endif
      /* Avoid memories with nonzero SUBREG_BYTE, as offsetting the memory
         may result in incorrect reference.  We should simplify all valid
         subregs of MEM anyway.  But allow this after reload because we
         might be called from cleanup_subreg_operands.

         ??? This is a kludge.  */
      if (!reload_completed && SUBREG_BYTE (op) != 0
          && MEM_P (sub))
        return 0;

      /* FLOAT_MODE subregs can't be paradoxical.  Combine will occasionally
         create such rtl, and we must reject it.  */
      if (SCALAR_FLOAT_MODE_P (GET_MODE (op))
          /* LRA can use subreg to store a floating point value in an
             integer mode.  Although the floating point and the
             integer modes need the same number of hard registers, the
             size of floating point mode can be less than the integer
             mode.  */
          && ! lra_in_progress 
          && GET_MODE_SIZE (GET_MODE (op)) > GET_MODE_SIZE (GET_MODE (sub)))
        return 0;

      op = sub;
      code = GET_CODE (op);
    }

  if (code == REG)
    return (REGNO (op) >= FIRST_PSEUDO_REGISTER
            || in_hard_reg_set_p (operand_reg_set, GET_MODE (op), REGNO (op)));

  if (code == MEM)
    {
      rtx y = XEXP (op, 0);

      if (! volatile_ok && MEM_VOLATILE_P (op))
        return 0;

      /* Use the mem's mode, since it will be reloaded thus.  */
      if (memory_address_addr_space_p (GET_MODE (op), y, MEM_ADDR_SPACE (op)))
        return 1;
    }

  return 0;
}
\f
/* Return 1 if OP is a valid memory address for a memory reference
   of mode MODE.

   The main use of this function is as a predicate in match_operand
   expressions in the machine description.  */

int
address_operand (rtx op, enum machine_mode mode)
{
  return memory_address_p (mode, op);
}

/* Return 1 if OP is a register reference of mode MODE.
   If MODE is VOIDmode, accept a register in any mode.

   The main use of this function is as a predicate in match_operand
   expressions in the machine description.  */

int
register_operand (rtx op, enum machine_mode mode)
{
  if (GET_MODE (op) != mode && mode != VOIDmode)
    return 0;

  if (GET_CODE (op) == SUBREG)
    {
      rtx sub = SUBREG_REG (op);

      /* Before reload, we can allow (SUBREG (MEM...)) as a register operand
         because it is guaranteed to be reloaded into one.
         Just make sure the MEM is valid in itself.
         (Ideally, (SUBREG (MEM)...) should not exist after reload,
         but currently it does result from (SUBREG (REG)...) where the
         reg went on the stack.)  */
      if (! reload_completed && MEM_P (sub))
        return general_operand (op, mode);

#ifdef CANNOT_CHANGE_MODE_CLASS
      if (REG_P (sub)
          && REGNO (sub) < FIRST_PSEUDO_REGISTER
          && REG_CANNOT_CHANGE_MODE_P (REGNO (sub), GET_MODE (sub), mode)
          && GET_MODE_CLASS (GET_MODE (sub)) != MODE_COMPLEX_INT
          && GET_MODE_CLASS (GET_MODE (sub)) != MODE_COMPLEX_FLOAT
          /* LRA can generate some invalid SUBREGS just for matched
             operand reload presentation.  LRA needs to treat them as
             valid.  */
          && ! LRA_SUBREG_P (op))
        return 0;
#endif

      /* FLOAT_MODE subregs can't be paradoxical.  Combine will occasionally
         create such rtl, and we must reject it.  */
      if (SCALAR_FLOAT_MODE_P (GET_MODE (op))
          /* LRA can use subreg to store a floating point value in an
             integer mode.  Although the floating point and the
             integer modes need the same number of hard registers, the
             size of floating point mode can be less than the integer
             mode.  */
          && ! lra_in_progress 
          && GET_MODE_SIZE (GET_MODE (op)) > GET_MODE_SIZE (GET_MODE (sub)))
        return 0;

      op = sub;
    }

  return (REG_P (op)
          && (REGNO (op) >= FIRST_PSEUDO_REGISTER
              || in_hard_reg_set_p (operand_reg_set,
                                    GET_MODE (op), REGNO (op))));
}

/* Return 1 for a register in Pmode; ignore the tested mode.  */

int
pmode_register_operand (rtx op, enum machine_mode mode ATTRIBUTE_UNUSED)
{
  return register_operand (op, Pmode);
}

/* Return 1 if OP should match a MATCH_SCRATCH, i.e., if it is a SCRATCH
   or a hard register.  */

int
scratch_operand (rtx op, enum machine_mode mode)
{
  if (GET_MODE (op) != mode && mode != VOIDmode)
    return 0;

  return (GET_CODE (op) == SCRATCH
          || (REG_P (op)
              && (lra_in_progress || REGNO (op) < FIRST_PSEUDO_REGISTER)));
}

/* Return 1 if OP is a valid immediate operand for mode MODE.

   The main use of this function is as a predicate in match_operand
   expressions in the machine description.  */

int
immediate_operand (rtx op, enum machine_mode mode)
{
  /* Don't accept CONST_INT or anything similar
     if the caller wants something floating.  */
  if (GET_MODE (op) == VOIDmode && mode != VOIDmode
      && GET_MODE_CLASS (mode) != MODE_INT
      && GET_MODE_CLASS (mode) != MODE_PARTIAL_INT)
    return 0;

  if (CONST_INT_P (op)
      && mode != VOIDmode
      && trunc_int_for_mode (INTVAL (op), mode) != INTVAL (op))
    return 0;

  return (CONSTANT_P (op)
          && (GET_MODE (op) == mode || mode == VOIDmode
              || GET_MODE (op) == VOIDmode)
          && (! flag_pic || LEGITIMATE_PIC_OPERAND_P (op))
          && targetm.legitimate_constant_p (mode == VOIDmode
                                            ? GET_MODE (op)
                                            : mode, op));
}

/* Returns 1 if OP is an operand that is a CONST_INT.  */

int
const_int_operand (rtx op, enum machine_mode mode)
{
  if (!CONST_INT_P (op))
    return 0;

  if (mode != VOIDmode
      && trunc_int_for_mode (INTVAL (op), mode) != INTVAL (op))
    return 0;

  return 1;
}

/* Returns 1 if OP is an operand that is a constant integer or constant
   floating-point number.  */

int
const_double_operand (rtx op, enum machine_mode mode)
{
  /* Don't accept CONST_INT or anything similar
     if the caller wants something floating.  */
  if (GET_MODE (op) == VOIDmode && mode != VOIDmode
      && GET_MODE_CLASS (mode) != MODE_INT
      && GET_MODE_CLASS (mode) != MODE_PARTIAL_INT)
    return 0;

  return ((CONST_DOUBLE_P (op) || CONST_INT_P (op))
          && (mode == VOIDmode || GET_MODE (op) == mode
              || GET_MODE (op) == VOIDmode));
}

/* Return 1 if OP is a general operand that is not an immediate operand.  */

int
nonimmediate_operand (rtx op, enum machine_mode mode)
{
  return (general_operand (op, mode) && ! CONSTANT_P (op));
}

/* Return 1 if OP is a register reference or immediate value of mode MODE.  */

int
nonmemory_operand (rtx op, enum machine_mode mode)
{
  if (CONSTANT_P (op))
    return immediate_operand (op, mode);

  if (GET_MODE (op) != mode && mode != VOIDmode)
    return 0;

  if (GET_CODE (op) == SUBREG)
    {
      /* Before reload, we can allow (SUBREG (MEM...)) as a register operand
         because it is guaranteed to be reloaded into one.
         Just make sure the MEM is valid in itself.
         (Ideally, (SUBREG (MEM)...) should not exist after reload,
         but currently it does result from (SUBREG (REG)...) where the
         reg went on the stack.)  */
      if (! reload_completed && MEM_P (SUBREG_REG (op)))
        return general_operand (op, mode);
      op = SUBREG_REG (op);
    }

  return (REG_P (op)
          && (REGNO (op) >= FIRST_PSEUDO_REGISTER
              || in_hard_reg_set_p (operand_reg_set,
                                    GET_MODE (op), REGNO (op))));
}

/* Return 1 if OP is a valid operand that stands for pushing a
   value of mode MODE onto the stack.

   The main use of this function is as a predicate in match_operand
   expressions in the machine description.  */

int
push_operand (rtx op, enum machine_mode mode)
{
  unsigned int rounded_size = GET_MODE_SIZE (mode);

#ifdef PUSH_ROUNDING
  rounded_size = PUSH_ROUNDING (rounded_size);
#endif

  if (!MEM_P (op))
    return 0;

  if (mode != VOIDmode && GET_MODE (op) != mode)
    return 0;

  op = XEXP (op, 0);

  if (rounded_size == GET_MODE_SIZE (mode))
    {
      if (GET_CODE (op) != STACK_PUSH_CODE)
        return 0;
    }
  else
    {
      if (GET_CODE (op) != PRE_MODIFY
          || GET_CODE (XEXP (op, 1)) != PLUS
          || XEXP (XEXP (op, 1), 0) != XEXP (op, 0)
          || !CONST_INT_P (XEXP (XEXP (op, 1), 1))
#ifdef STACK_GROWS_DOWNWARD
          || INTVAL (XEXP (XEXP (op, 1), 1)) != - (int) rounded_size
#else
          || INTVAL (XEXP (XEXP (op, 1), 1)) != (int) rounded_size
#endif
          )
        return 0;
    }

  return XEXP (op, 0) == stack_pointer_rtx;
}

/* Return 1 if OP is a valid operand that stands for popping a
   value of mode MODE off the stack.

   The main use of this function is as a predicate in match_operand
   expressions in the machine description.  */

int
pop_operand (rtx op, enum machine_mode mode)
{
  if (!MEM_P (op))
    return 0;

  if (mode != VOIDmode && GET_MODE (op) != mode)
    return 0;

  op = XEXP (op, 0);

  if (GET_CODE (op) != STACK_POP_CODE)
    return 0;

  return XEXP (op, 0) == stack_pointer_rtx;
}

/* Return 1 if ADDR is a valid memory address
   for mode MODE in address space AS.  */

int
memory_address_addr_space_p (enum machine_mode mode ATTRIBUTE_UNUSED,
                             rtx addr, addr_space_t as)
{
#ifdef GO_IF_LEGITIMATE_ADDRESS
  gcc_assert (ADDR_SPACE_GENERIC_P (as));
  GO_IF_LEGITIMATE_ADDRESS (mode, addr, win);
  return 0;

 win:
  return 1;
#else
  return targetm.addr_space.legitimate_address_p (mode, addr, 0, as);
#endif
}

/* Return 1 if OP is a valid memory reference with mode MODE,
   including a valid address.

   The main use of this function is as a predicate in match_operand
   expressions in the machine description.  */

int
memory_operand (rtx op, enum machine_mode mode)
{
  rtx inner;

  if (! reload_completed)
    /* Note that no SUBREG is a memory operand before end of reload pass,
       because (SUBREG (MEM...)) forces reloading into a register.  */
    return MEM_P (op) && general_operand (op, mode);

  if (mode != VOIDmode && GET_MODE (op) != mode)
    return 0;

  inner = op;
  if (GET_CODE (inner) == SUBREG)
    inner = SUBREG_REG (inner);

  return (MEM_P (inner) && general_operand (op, mode));
}

/* Return 1 if OP is a valid indirect memory reference with mode MODE;
   that is, a memory reference whose address is a general_operand.  */

int
indirect_operand (rtx op, enum machine_mode mode)
{
  /* Before reload, a SUBREG isn't in memory (see memory_operand, above).  */
  if (! reload_completed
      && GET_CODE (op) == SUBREG && MEM_P (SUBREG_REG (op)))
    {
      int offset = SUBREG_BYTE (op);
      rtx inner = SUBREG_REG (op);

      if (mode != VOIDmode && GET_MODE (op) != mode)
        return 0;

      /* The only way that we can have a general_operand as the resulting
         address is if OFFSET is zero and the address already is an operand
         or if the address is (plus Y (const_int -OFFSET)) and Y is an
         operand.  */

      return ((offset == 0 && general_operand (XEXP (inner, 0), Pmode))
              || (GET_CODE (XEXP (inner, 0)) == PLUS
                  && CONST_INT_P (XEXP (XEXP (inner, 0), 1))
                  && INTVAL (XEXP (XEXP (inner, 0), 1)) == -offset
                  && general_operand (XEXP (XEXP (inner, 0), 0), Pmode)));
    }

  return (MEM_P (op)
          && memory_operand (op, mode)
          && general_operand (XEXP (op, 0), Pmode));
}

/* Return 1 if this is an ordered comparison operator (not including
   ORDERED and UNORDERED).  */

int
ordered_comparison_operator (rtx op, enum machine_mode mode)
{
  if (mode != VOIDmode && GET_MODE (op) != mode)
    return false;
  switch (GET_CODE (op))
    {
    case EQ:
    case NE:
    case LT:
    case LTU:
    case LE:
    case LEU:
    case GT:
    case GTU:
    case GE:
    case GEU:
      return true;
    default:
      return false;
    }
}

/* Return 1 if this is a comparison operator.  This allows the use of
   MATCH_OPERATOR to recognize all the branch insns.  */

int
comparison_operator (rtx op, enum machine_mode mode)
{
  return ((mode == VOIDmode || GET_MODE (op) == mode)
          && COMPARISON_P (op));
}
\f
/* If BODY is an insn body that uses ASM_OPERANDS, return it.  */

rtx
extract_asm_operands (rtx body)
{
  rtx tmp;
  switch (GET_CODE (body))
    {
    case ASM_OPERANDS:
      return body;

    case SET:
      /* Single output operand: BODY is (set OUTPUT (asm_operands ...)).  */
      tmp = SET_SRC (body);
      if (GET_CODE (tmp) == ASM_OPERANDS)
        return tmp;
      break;

    case PARALLEL:
      tmp = XVECEXP (body, 0, 0);
      if (GET_CODE (tmp) == ASM_OPERANDS)
        return tmp;
      if (GET_CODE (tmp) == SET)
        {
          tmp = SET_SRC (tmp);
          if (GET_CODE (tmp) == ASM_OPERANDS)
            return tmp;
        }
      break;

    default:
      break;
    }
  return NULL;
}

/* If BODY is an insn body that uses ASM_OPERANDS,
   return the number of operands (both input and output) in the insn.
   Otherwise return -1.  */

int
asm_noperands (const_rtx body)
{
  rtx asm_op = extract_asm_operands (CONST_CAST_RTX (body));
  int n_sets = 0;

  if (asm_op == NULL)
    return -1;

  if (GET_CODE (body) == SET)
    n_sets = 1;
  else if (GET_CODE (body) == PARALLEL)
    {
      int i;
      if (GET_CODE (XVECEXP (body, 0, 0)) == SET)
        {
          /* Multiple output operands, or 1 output plus some clobbers:
             body is
             [(set OUTPUT (asm_operands ...))... (clobber (reg ...))...].  */
          /* Count backwards through CLOBBERs to determine number of SETs.  */
          for (i = XVECLEN (body, 0); i > 0; i--)
            {
              if (GET_CODE (XVECEXP (body, 0, i - 1)) == SET)
                break;
              if (GET_CODE (XVECEXP (body, 0, i - 1)) != CLOBBER)
                return -1;
            }

          /* N_SETS is now number of output operands.  */
          n_sets = i;

          /* Verify that all the SETs we have
             came from a single original asm_operands insn
             (so that invalid combinations are blocked).  */
          for (i = 0; i < n_sets; i++)
            {
              rtx elt = XVECEXP (body, 0, i);
              if (GET_CODE (elt) != SET)
                return -1;
              if (GET_CODE (SET_SRC (elt)) != ASM_OPERANDS)
                return -1;
              /* If these ASM_OPERANDS rtx's came from different original insns
                 then they aren't allowed together.  */
              if (ASM_OPERANDS_INPUT_VEC (SET_SRC (elt))
                  != ASM_OPERANDS_INPUT_VEC (asm_op))
                return -1;
            }
        }
      else
        {
          /* 0 outputs, but some clobbers:
             body is [(asm_operands ...) (clobber (reg ...))...].  */
          /* Make sure all the other parallel things really are clobbers.  */
          for (i = XVECLEN (body, 0) - 1; i > 0; i--)
            if (GET_CODE (XVECEXP (body, 0, i)) != CLOBBER)
              return -1;
        }
    }

  return (ASM_OPERANDS_INPUT_LENGTH (asm_op)
          + ASM_OPERANDS_LABEL_LENGTH (asm_op) + n_sets);
}

/* Assuming BODY is an insn body that uses ASM_OPERANDS,
   copy its operands (both input and output) into the vector OPERANDS,
   the locations of the operands within the insn into the vector OPERAND_LOCS,
   and the constraints for the operands into CONSTRAINTS.
   Write the modes of the operands into MODES.
   Return the assembler-template.

   If MODES, OPERAND_LOCS, CONSTRAINTS or OPERANDS is 0,
   we don't store that info.  */

const char *
decode_asm_operands (rtx body, rtx *operands, rtx **operand_locs,
                     const char **constraints, enum machine_mode *modes,
                     location_t *loc)
{
  int nbase = 0, n, i;
  rtx asmop;

  switch (GET_CODE (body))
    {
    case ASM_OPERANDS:
      /* Zero output asm: BODY is (asm_operands ...).  */
      asmop = body;
      break;

    case SET:
      /* Single output asm: BODY is (set OUTPUT (asm_operands ...)).  */
      asmop = SET_SRC (body);

      /* The output is in the SET.
         Its constraint is in the ASM_OPERANDS itself.  */
      if (operands)
        operands[0] = SET_DEST (body);
      if (operand_locs)
        operand_locs[0] = &SET_DEST (body);
      if (constraints)
        constraints[0] = ASM_OPERANDS_OUTPUT_CONSTRAINT (asmop);
      if (modes)
        modes[0] = GET_MODE (SET_DEST (body));
      nbase = 1;
      break;

    case PARALLEL:
      {
        int nparallel = XVECLEN (body, 0); /* Includes CLOBBERs.  */

        asmop = XVECEXP (body, 0, 0);
        if (GET_CODE (asmop) == SET)
          {
            asmop = SET_SRC (asmop);

            /* At least one output, plus some CLOBBERs.  The outputs are in
               the SETs.  Their constraints are in the ASM_OPERANDS itself.  */
            for (i = 0; i < nparallel; i++)
              {
                if (GET_CODE (XVECEXP (body, 0, i)) == CLOBBER)
                  break;                /* Past last SET */
                if (operands)
                  operands[i] = SET_DEST (XVECEXP (body, 0, i));
                if (operand_locs)
                  operand_locs[i] = &SET_DEST (XVECEXP (body, 0, i));
                if (constraints)
                  constraints[i] = XSTR (SET_SRC (XVECEXP (body, 0, i)), 1);
                if (modes)
                  modes[i] = GET_MODE (SET_DEST (XVECEXP (body, 0, i)));
              }
            nbase = i;
          }
        break;
      }

    default:
      gcc_unreachable ();
    }

  n = ASM_OPERANDS_INPUT_LENGTH (asmop);
  for (i = 0; i < n; i++)
    {
      if (operand_locs)
        operand_locs[nbase + i] = &ASM_OPERANDS_INPUT (asmop, i);
      if (operands)
        operands[nbase + i] = ASM_OPERANDS_INPUT (asmop, i);
      if (constraints)
        constraints[nbase + i] = ASM_OPERANDS_INPUT_CONSTRAINT (asmop, i);
      if (modes)
        modes[nbase + i] = ASM_OPERANDS_INPUT_MODE (asmop, i);
    }
  nbase += n;

  n = ASM_OPERANDS_LABEL_LENGTH (asmop);
  for (i = 0; i < n; i++)
    {
      if (operand_locs)
        operand_locs[nbase + i] = &ASM_OPERANDS_LABEL (asmop, i);
      if (operands)
        operands[nbase + i] = ASM_OPERANDS_LABEL (asmop, i);
      if (constraints)
        constraints[nbase + i] = "";
      if (modes)
        modes[nbase + i] = Pmode;
    }

  if (loc)
    *loc = ASM_OPERANDS_SOURCE_LOCATION (asmop);

  return ASM_OPERANDS_TEMPLATE (asmop);
}

/* Check if an asm_operand matches its constraints.
   Return > 0 if ok, = 0 if bad, < 0 if inconclusive.  */

int
asm_operand_ok (rtx op, const char *constraint, const char **constraints)
{
  int result = 0;
#ifdef AUTO_INC_DEC
  bool incdec_ok = false;
#endif

  /* Use constrain_operands after reload.  */
  gcc_assert (!reload_completed);

  /* Empty constraint string is the same as "X,...,X", i.e. X for as
     many alternatives as required to match the other operands.  */
  if (*constraint == '\0')
    result = 1;

  while (*constraint)
    {
      char c = *constraint;
      int len;
      switch (c)
        {
        case ',':
          constraint++;
          continue;
        case '=':
        case '+':
        case '*':
        case '%':
        case '!':
        case '#':
        case '&':
        case '?':
          break;

        case '0': case '1': case '2': case '3': case '4':
        case '5': case '6': case '7': case '8': case '9':
          /* If caller provided constraints pointer, look up
             the matching constraint.  Otherwise, our caller should have
             given us the proper matching constraint, but we can't
             actually fail the check if they didn't.  Indicate that
             results are inconclusive.  */
          if (constraints)
            {
              char *end;
              unsigned long match;

              match = strtoul (constraint, &end, 10);
              if (!result)
                result = asm_operand_ok (op, constraints[match], NULL);
              constraint = (const char *) end;
            }
          else
            {
              do
                constraint++;
              while (ISDIGIT (*constraint));
              if (! result)
                result = -1;
            }
          continue;

        case 'p':
          if (address_operand (op, VOIDmode))
            result = 1;
          break;

        case TARGET_MEM_CONSTRAINT:
        case 'V': /* non-offsettable */
          if (memory_operand (op, VOIDmode))
            result = 1;
          break;

        case 'o': /* offsettable */
          if (offsettable_nonstrict_memref_p (op))
            result = 1;
          break;

        case '<':
          /* ??? Before auto-inc-dec, auto inc/dec insns are not supposed to exist,
             excepting those that expand_call created.  Further, on some
             machines which do not have generalized auto inc/dec, an inc/dec
             is not a memory_operand.

             Match any memory and hope things are resolved after reload.  */

          if (MEM_P (op)
              && (1
                  || GET_CODE (XEXP (op, 0)) == PRE_DEC
                  || GET_CODE (XEXP (op, 0)) == POST_DEC))
            result = 1;
#ifdef AUTO_INC_DEC
          incdec_ok = true;
#endif
          break;

        case '>':
          if (MEM_P (op)
              && (1
                  || GET_CODE (XEXP (op, 0)) == PRE_INC
                  || GET_CODE (XEXP (op, 0)) == POST_INC))
            result = 1;
#ifdef AUTO_INC_DEC
          incdec_ok = true;
#endif
          break;

        case 'E':
        case 'F':
          if (CONST_DOUBLE_AS_FLOAT_P (op) 
              || (GET_CODE (op) == CONST_VECTOR
                  && GET_MODE_CLASS (GET_MODE (op)) == MODE_VECTOR_FLOAT))
            result = 1;
          break;

        case 'G':
          if (CONST_DOUBLE_AS_FLOAT_P (op)
              && CONST_DOUBLE_OK_FOR_CONSTRAINT_P (op, 'G', constraint))
            result = 1;
          break;
        case 'H':
          if (CONST_DOUBLE_AS_FLOAT_P (op)
              && CONST_DOUBLE_OK_FOR_CONSTRAINT_P (op, 'H', constraint))
            result = 1;
          break;

        case 's':
          if (CONST_SCALAR_INT_P (op))
            break;
          /* Fall through.  */

        case 'i':
          if (CONSTANT_P (op) && (! flag_pic || LEGITIMATE_PIC_OPERAND_P (op)))
            result = 1;
          break;

        case 'n':
          if (CONST_SCALAR_INT_P (op))
            result = 1;
          break;

        case 'I':
          if (CONST_INT_P (op)
              && CONST_OK_FOR_CONSTRAINT_P (INTVAL (op), 'I', constraint))
            result = 1;
          break;
        case 'J':
          if (CONST_INT_P (op)
              && CONST_OK_FOR_CONSTRAINT_P (INTVAL (op), 'J', constraint))
            result = 1;
          break;
        case 'K':
          if (CONST_INT_P (op)
              && CONST_OK_FOR_CONSTRAINT_P (INTVAL (op), 'K', constraint))
            result = 1;
          break;
        case 'L':
          if (CONST_INT_P (op)
              && CONST_OK_FOR_CONSTRAINT_P (INTVAL (op), 'L', constraint))
            result = 1;
          break;
        case 'M':
          if (CONST_INT_P (op)
              && CONST_OK_FOR_CONSTRAINT_P (INTVAL (op), 'M', constraint))
            result = 1;
          break;
        case 'N':
          if (CONST_INT_P (op)
              && CONST_OK_FOR_CONSTRAINT_P (INTVAL (op), 'N', constraint))
            result = 1;
          break;
        case 'O':
          if (CONST_INT_P (op)
              && CONST_OK_FOR_CONSTRAINT_P (INTVAL (op), 'O', constraint))
            result = 1;
          break;
        case 'P':
          if (CONST_INT_P (op)
              && CONST_OK_FOR_CONSTRAINT_P (INTVAL (op), 'P', constraint))
            result = 1;
          break;

        case 'X':
          result = 1;
          break;

        case 'g':
          if (general_operand (op, VOIDmode))
            result = 1;
          break;

        default:
          /* For all other letters, we first check for a register class,
             otherwise it is an EXTRA_CONSTRAINT.  */
          if (REG_CLASS_FROM_CONSTRAINT (c, constraint) != NO_REGS)
            {
            case 'r':
              if (GET_MODE (op) == BLKmode)
                break;
              if (register_operand (op, VOIDmode))
                result = 1;
            }
#ifdef EXTRA_CONSTRAINT_STR
          else if (EXTRA_MEMORY_CONSTRAINT (c, constraint))
            /* Every memory operand can be reloaded to fit.  */
            result = result || memory_operand (op, VOIDmode);
          else if (EXTRA_ADDRESS_CONSTRAINT (c, constraint))
            /* Every address operand can be reloaded to fit.  */
            result = result || address_operand (op, VOIDmode);
          else if (EXTRA_CONSTRAINT_STR (op, c, constraint))
            result = 1;
#endif
          break;
        }
      len = CONSTRAINT_LEN (c, constraint);
      do
        constraint++;
      while (--len && *constraint);
      if (len)
        return 0;
    }

#ifdef AUTO_INC_DEC
  /* For operands without < or > constraints reject side-effects.  */
  if (!incdec_ok && result && MEM_P (op))
    switch (GET_CODE (XEXP (op, 0)))
      {
      case PRE_INC:
      case POST_INC:
      case PRE_DEC:
      case POST_DEC:
      case PRE_MODIFY:
      case POST_MODIFY:
        return 0;
      default:
        break;
      }
#endif

  return result;
}
\f
/* Given an rtx *P, if it is a sum containing an integer constant term,
   return the location (type rtx *) of the pointer to that constant term.
   Otherwise, return a null pointer.  */

rtx *
find_constant_term_loc (rtx *p)
{
  rtx *tem;
  enum rtx_code code = GET_CODE (*p);

  /* If *P IS such a constant term, P is its location.  */

  if (code == CONST_INT || code == SYMBOL_REF || code == LABEL_REF
      || code == CONST)
    return p;

  /* Otherwise, if not a sum, it has no constant term.  */

  if (GET_CODE (*p) != PLUS)
    return 0;

  /* If one of the summands is constant, return its location.  */

  if (XEXP (*p, 0) && CONSTANT_P (XEXP (*p, 0))
      && XEXP (*p, 1) && CONSTANT_P (XEXP (*p, 1)))
    return p;

  /* Otherwise, check each summand for containing a constant term.  */

  if (XEXP (*p, 0) != 0)
    {
      tem = find_constant_term_loc (&XEXP (*p, 0));
      if (tem != 0)
        return tem;
    }

  if (XEXP (*p, 1) != 0)
    {
      tem = find_constant_term_loc (&XEXP (*p, 1));
      if (tem != 0)
        return tem;
    }

  return 0;
}
\f
/* Return 1 if OP is a memory reference
   whose address contains no side effects
   and remains valid after the addition
   of a positive integer less than the
   size of the object being referenced.

   We assume that the original address is valid and do not check it.

   This uses strict_memory_address_p as a subroutine, so
   don't use it before reload.  */

int
offsettable_memref_p (rtx op)
{
  return ((MEM_P (op))
          && offsettable_address_addr_space_p (1, GET_MODE (op), XEXP (op, 0),
                                               MEM_ADDR_SPACE (op)));
}

/* Similar, but don't require a strictly valid mem ref:
   consider pseudo-regs valid as index or base regs.  */

int
offsettable_nonstrict_memref_p (rtx op)
{
  return ((MEM_P (op))
          && offsettable_address_addr_space_p (0, GET_MODE (op), XEXP (op, 0),
                                               MEM_ADDR_SPACE (op)));
}

/* Return 1 if Y is a memory address which contains no side effects
   and would remain valid for address space AS after the addition of
   a positive integer less than the size of that mode.

   We assume that the original address is valid and do not check it.
   We do check that it is valid for narrower modes.

   If STRICTP is nonzero, we require a strictly valid address,
   for the sake of use in reload.c.  */

int
offsettable_address_addr_space_p (int strictp, enum machine_mode mode, rtx y,
                                  addr_space_t as)
{
  enum rtx_code ycode = GET_CODE (y);
  rtx z;
  rtx y1 = y;
  rtx *y2;
  int (*addressp) (enum machine_mode, rtx, addr_space_t) =
    (strictp ? strict_memory_address_addr_space_p
             : memory_address_addr_space_p);
  unsigned int mode_sz = GET_MODE_SIZE (mode);

  if (CONSTANT_ADDRESS_P (y))
    return 1;

  /* Adjusting an offsettable address involves changing to a narrower mode.
     Make sure that's OK.  */

  if (mode_dependent_address_p (y, as))
    return 0;

  enum machine_mode address_mode = GET_MODE (y);
  if (address_mode == VOIDmode)
    address_mode = targetm.addr_space.address_mode (as);
#ifdef POINTERS_EXTEND_UNSIGNED
  enum machine_mode pointer_mode = targetm.addr_space.pointer_mode (as);
#endif

  /* ??? How much offset does an offsettable BLKmode reference need?
     Clearly that depends on the situation in which it's being used.
     However, the current situation in which we test 0xffffffff is
     less than ideal.  Caveat user.  */
  if (mode_sz == 0)
    mode_sz = BIGGEST_ALIGNMENT / BITS_PER_UNIT;

  /* If the expression contains a constant term,
     see if it remains valid when max possible offset is added.  */

  if ((ycode == PLUS) && (y2 = find_constant_term_loc (&y1)))
    {
      int good;

      y1 = *y2;
      *y2 = plus_constant (address_mode, *y2, mode_sz - 1);
      /* Use QImode because an odd displacement may be automatically invalid
         for any wider mode.  But it should be valid for a single byte.  */
      good = (*addressp) (QImode, y, as);

      /* In any case, restore old contents of memory.  */
      *y2 = y1;
      return good;
    }

  if (GET_RTX_CLASS (ycode) == RTX_AUTOINC)
    return 0;

  /* The offset added here is chosen as the maximum offset that
     any instruction could need to add when operating on something
     of the specified mode.  We assume that if Y and Y+c are
     valid addresses then so is Y+d for all 0<d<c.  adjust_address will
     go inside a LO_SUM here, so we do so as well.  */
  if (GET_CODE (y) == LO_SUM
      && mode != BLKmode
      && mode_sz <= GET_MODE_ALIGNMENT (mode) / BITS_PER_UNIT)
    z = gen_rtx_LO_SUM (address_mode, XEXP (y, 0),
                        plus_constant (address_mode, XEXP (y, 1),
                                       mode_sz - 1));
#ifdef POINTERS_EXTEND_UNSIGNED
  /* Likewise for a ZERO_EXTEND from pointer_mode.  */
  else if (POINTERS_EXTEND_UNSIGNED > 0
           && GET_CODE (y) == ZERO_EXTEND
           && GET_MODE (XEXP (y, 0)) == pointer_mode)
    z = gen_rtx_ZERO_EXTEND (address_mode,
                             plus_constant (pointer_mode, XEXP (y, 0),
                                            mode_sz - 1));
#endif
  else
    z = plus_constant (address_mode, y, mode_sz - 1);

  /* Use QImode because an odd displacement may be automatically invalid
     for any wider mode.  But it should be valid for a single byte.  */
  return (*addressp) (QImode, z, as);
}

/* Return 1 if ADDR is an address-expression whose effect depends
   on the mode of the memory reference it is used in.

   ADDRSPACE is the address space associated with the address.

   Autoincrement addressing is a typical example of mode-dependence
   because the amount of the increment depends on the mode.  */

bool
mode_dependent_address_p (rtx addr, addr_space_t addrspace)
{
  /* Auto-increment addressing with anything other than post_modify
     or pre_modify always introduces a mode dependency.  Catch such
     cases now instead of deferring to the target.  */
  if (GET_CODE (addr) == PRE_INC
      || GET_CODE (addr) == POST_INC
      || GET_CODE (addr) == PRE_DEC
      || GET_CODE (addr) == POST_DEC)
    return true;

  return targetm.mode_dependent_address_p (addr, addrspace);
}
\f
/* Like extract_insn, but save insn extracted and don't extract again, when
   called again for the same insn expecting that recog_data still contain the
   valid information.  This is used primary by gen_attr infrastructure that
   often does extract insn again and again.  */
void
extract_insn_cached (rtx insn)
{
  if (recog_data.insn == insn && INSN_CODE (insn) >= 0)
    return;
  extract_insn (insn);
  recog_data.insn = insn;
}

/* Do cached extract_insn, constrain_operands and complain about failures.
   Used by insn_attrtab.  */
void
extract_constrain_insn_cached (rtx insn)
{
  extract_insn_cached (insn);
  if (which_alternative == -1
      && !constrain_operands (reload_completed))
    fatal_insn_not_found (insn);
}

/* Do cached constrain_operands and complain about failures.  */
int
constrain_operands_cached (int strict)
{
  if (which_alternative == -1)
    return constrain_operands (strict);
  else
    return 1;
}
\f
/* Analyze INSN and fill in recog_data.  */

void
extract_insn (rtx insn)
{
  int i;
  int icode;
  int noperands;
  rtx body = PATTERN (insn);

  recog_data.n_operands = 0;
  recog_data.n_alternatives = 0;
  recog_data.n_dups = 0;
  recog_data.is_asm = false;

  switch (GET_CODE (body))
    {
    case USE:
    case CLOBBER:
    case ASM_INPUT:
    case ADDR_VEC:
    case ADDR_DIFF_VEC:
    case VAR_LOCATION:
      return;

    case SET:
      if (GET_CODE (SET_SRC (body)) == ASM_OPERANDS)
        goto asm_insn;
      else
        goto normal_insn;
    case PARALLEL:
      if ((GET_CODE (XVECEXP (body, 0, 0)) == SET
           && GET_CODE (SET_SRC (XVECEXP (body, 0, 0))) == ASM_OPERANDS)
          || GET_CODE (XVECEXP (body, 0, 0)) == ASM_OPERANDS)
        goto asm_insn;
      else
        goto normal_insn;
    case ASM_OPERANDS:
    asm_insn:
      recog_data.n_operands = noperands = asm_noperands (body);
      if (noperands >= 0)
        {
          /* This insn is an `asm' with operands.  */

          /* expand_asm_operands makes sure there aren't too many operands.  */
          gcc_assert (noperands <= MAX_RECOG_OPERANDS);

          /* Now get the operand values and constraints out of the insn.  */
          decode_asm_operands (body, recog_data.operand,
                               recog_data.operand_loc,
                               recog_data.constraints,
                               recog_data.operand_mode, NULL);
          memset (recog_data.is_operator, 0, sizeof recog_data.is_operator);
          if (noperands > 0)
            {
              const char *p =  recog_data.constraints[0];
              recog_data.n_alternatives = 1;
              while (*p)
                recog_data.n_alternatives += (*p++ == ',');
            }
          recog_data.is_asm = true;
          break;
        }
      fatal_insn_not_found (insn);

    default:
    normal_insn:
      /* Ordinary insn: recognize it, get the operands via insn_extract
         and get the constraints.  */

      icode = recog_memoized (insn);
      if (icode < 0)
        fatal_insn_not_found (insn);

      recog_data.n_operands = noperands = insn_data[icode].n_operands;
      recog_data.n_alternatives = insn_data[icode].n_alternatives;
      recog_data.n_dups = insn_data[icode].n_dups;

      insn_extract (insn);

      for (i = 0; i < noperands; i++)
        {
          recog_data.constraints[i] = insn_data[icode].operand[i].constraint;
          recog_data.is_operator[i] = insn_data[icode].operand[i].is_operator;
          recog_data.operand_mode[i] = insn_data[icode].operand[i].mode;
          /* VOIDmode match_operands gets mode from their real operand.  */
          if (recog_data.operand_mode[i] == VOIDmode)
            recog_data.operand_mode[i] = GET_MODE (recog_data.operand[i]);
        }
    }
  for (i = 0; i < noperands; i++)
    recog_data.operand_type[i]
      = (recog_data.constraints[i][0] == '=' ? OP_OUT
         : recog_data.constraints[i][0] == '+' ? OP_INOUT
         : OP_IN);

  gcc_assert (recog_data.n_alternatives <= MAX_RECOG_ALTERNATIVES);

  if (INSN_CODE (insn) < 0)
    for (i = 0; i < recog_data.n_alternatives; i++)
      recog_data.alternative_enabled_p[i] = true;
  else
    {
      recog_data.insn = insn;
      for (i = 0; i < recog_data.n_alternatives; i++)
        {
          which_alternative = i;
          recog_data.alternative_enabled_p[i]
            = HAVE_ATTR_enabled ? get_attr_enabled (insn) : 1;
        }
    }

  recog_data.insn = NULL;
  which_alternative = -1;
}

/* After calling extract_insn, you can use this function to extract some
   information from the constraint strings into a more usable form.
   The collected data is stored in recog_op_alt.  */
void
preprocess_constraints (void)
{
  int i;

  for (i = 0; i < recog_data.n_operands; i++)
    memset (recog_op_alt[i], 0, (recog_data.n_alternatives
                                 * sizeof (struct operand_alternative)));

  for (i = 0; i < recog_data.n_operands; i++)
    {
      int j;
      struct operand_alternative *op_alt;
      const char *p = recog_data.constraints[i];

      op_alt = recog_op_alt[i];

      for (j = 0; j < recog_data.n_alternatives; j++)
        {
          op_alt[j].cl = NO_REGS;
          op_alt[j].constraint = p;
          op_alt[j].matches = -1;
          op_alt[j].matched = -1;

          if (!recog_data.alternative_enabled_p[j])
            {
              p = skip_alternative (p);
              continue;
            }

          if (*p == '\0' || *p == ',')
            {
              op_alt[j].anything_ok = 1;
              continue;
            }

          for (;;)
            {
              char c = *p;
              if (c == '#')
                do
                  c = *++p;
                while (c != ',' && c != '\0');
              if (c == ',' || c == '\0')
                {
                  p++;
                  break;
                }

              switch (c)
                {
                case '=': case '+': case '*': case '%':
                case 'E': case 'F': case 'G': case 'H':
                case 's': case 'i': case 'n':
                case 'I': case 'J': case 'K': case 'L':
                case 'M': case 'N': case 'O': case 'P':
                  /* These don't say anything we care about.  */
                  break;

                case '?':
                  op_alt[j].reject += 6;
                  break;
                case '!':
                  op_alt[j].reject += 600;
                  break;
                case '&':
                  op_alt[j].earlyclobber = 1;
                  break;

                case '0': case '1': case '2': case '3': case '4':
                case '5': case '6': case '7': case '8': case '9':
                  {
                    char *end;
                    op_alt[j].matches = strtoul (p, &end, 10);
                    recog_op_alt[op_alt[j].matches][j].matched = i;
                    p = end;
                  }
                  continue;

                case TARGET_MEM_CONSTRAINT:
                  op_alt[j].memory_ok = 1;
                  break;
                case '<':
                  op_alt[j].decmem_ok = 1;
                  break;
                case '>':
                  op_alt[j].incmem_ok = 1;
                  break;
                case 'V':
                  op_alt[j].nonoffmem_ok = 1;
                  break;
                case 'o':
                  op_alt[j].offmem_ok = 1;
                  break;
                case 'X':
                  op_alt[j].anything_ok = 1;
                  break;

                case 'p':
                  op_alt[j].is_address = 1;
                  op_alt[j].cl = reg_class_subunion[(int) op_alt[j].cl]
                      [(int) base_reg_class (VOIDmode, ADDR_SPACE_GENERIC,
                                             ADDRESS, SCRATCH)];
                  break;

                case 'g':
                case 'r':
                  op_alt[j].cl =
                   reg_class_subunion[(int) op_alt[j].cl][(int) GENERAL_REGS];
                  break;

                default:
                  if (EXTRA_MEMORY_CONSTRAINT (c, p))
                    {
                      op_alt[j].memory_ok = 1;
                      break;
                    }
                  if (EXTRA_ADDRESS_CONSTRAINT (c, p))
                    {
                      op_alt[j].is_address = 1;
                      op_alt[j].cl
                        = (reg_class_subunion
                           [(int) op_alt[j].cl]
                           [(int) base_reg_class (VOIDmode, ADDR_SPACE_GENERIC,
                                                  ADDRESS, SCRATCH)]);
                      break;
                    }

                  op_alt[j].cl
                    = (reg_class_subunion
                       [(int) op_alt[j].cl]
                       [(int) REG_CLASS_FROM_CONSTRAINT ((unsigned char) c, p)]);
                  break;
                }
              p += CONSTRAINT_LEN (c, p);
            }
        }
    }
}

/* Check the operands of an insn against the insn's operand constraints
   and return 1 if they are valid.
   The information about the insn's operands, constraints, operand modes
   etc. is obtained from the global variables set up by extract_insn.

   WHICH_ALTERNATIVE is set to a number which indicates which
   alternative of constraints was matched: 0 for the first alternative,
   1 for the next, etc.

   In addition, when two operands are required to match
   and it happens that the output operand is (reg) while the
   input operand is --(reg) or ++(reg) (a pre-inc or pre-dec),
   make the output operand look like the input.
   This is because the output operand is the one the template will print.

   This is used in final, just before printing the assembler code and by
   the routines that determine an insn's attribute.

   If STRICT is a positive nonzero value, it means that we have been
   called after reload has been completed.  In that case, we must
   do all checks strictly.  If it is zero, it means that we have been called
   before reload has completed.  In that case, we first try to see if we can
   find an alternative that matches strictly.  If not, we try again, this
   time assuming that reload will fix up the insn.  This provides a "best
   guess" for the alternative and is used to compute attributes of insns prior
   to reload.  A negative value of STRICT is used for this internal call.  */

struct funny_match
{
  int this_op, other;
};

int
constrain_operands (int strict)
{
  const char *constraints[MAX_RECOG_OPERANDS];
  int matching_operands[MAX_RECOG_OPERANDS];
  int earlyclobber[MAX_RECOG_OPERANDS];
  int c;

  struct funny_match funny_match[MAX_RECOG_OPERANDS];
  int funny_match_index;

  which_alternative = 0;
  if (recog_data.n_operands == 0 || recog_data.n_alternatives == 0)
    return 1;

  for (c = 0; c < recog_data.n_operands; c++)
    {
      constraints[c] = recog_data.constraints[c];
      matching_operands[c] = -1;
    }

  do
    {
      int seen_earlyclobber_at = -1;
      int opno;
      int lose = 0;
      funny_match_index = 0;

      if (!recog_data.alternative_enabled_p[which_alternative])
        {
          int i;

          for (i = 0; i < recog_data.n_operands; i++)
            constraints[i] = skip_alternative (constraints[i]);

          which_alternative++;
          continue;
        }

      for (opno = 0; opno < recog_data.n_operands; opno++)
        {
          rtx op = recog_data.operand[opno];
          enum machine_mode mode = GET_MODE (op);
          const char *p = constraints[opno];
          int offset = 0;
          int win = 0;
          int val;
          int len;

          earlyclobber[opno] = 0;

          /* A unary operator may be accepted by the predicate, but it
             is irrelevant for matching constraints.  */
          if (UNARY_P (op))
            op = XEXP (op, 0);

          if (GET_CODE (op) == SUBREG)
            {
              if (REG_P (SUBREG_REG (op))
                  && REGNO (SUBREG_REG (op)) < FIRST_PSEUDO_REGISTER)
                offset = subreg_regno_offset (REGNO (SUBREG_REG (op)),
                                              GET_MODE (SUBREG_REG (op)),
                                              SUBREG_BYTE (op),
                                              GET_MODE (op));
              op = SUBREG_REG (op);
            }

          /* An empty constraint or empty alternative
             allows anything which matched the pattern.  */
          if (*p == 0 || *p == ',')
            win = 1;

          do
            switch (c = *p, len = CONSTRAINT_LEN (c, p), c)
              {
              case '\0':
                len = 0;
                break;
              case ',':
                c = '\0';
                break;

              case '?':  case '!': case '*':  case '%':
              case '=':  case '+':
                break;

              case '#':
                /* Ignore rest of this alternative as far as
                   constraint checking is concerned.  */
                do
                  p++;
                while (*p && *p != ',');
                len = 0;
                break;

              case '&':
                earlyclobber[opno] = 1;
                if (seen_earlyclobber_at < 0)
                  seen_earlyclobber_at = opno;
                break;

              case '0':  case '1':  case '2':  case '3':  case '4':
              case '5':  case '6':  case '7':  case '8':  case '9':
                {
                  /* This operand must be the same as a previous one.
                     This kind of constraint is used for instructions such
                     as add when they take only two operands.

                     Note that the lower-numbered operand is passed first.

                     If we are not testing strictly, assume that this
                     constraint will be satisfied.  */

                  char *end;
                  int match;

                  match = strtoul (p, &end, 10);
                  p = end;

                  if (strict < 0)
                    val = 1;
                  else
                    {
                      rtx op1 = recog_data.operand[match];
                      rtx op2 = recog_data.operand[opno];

                      /* A unary operator may be accepted by the predicate,
                         but it is irrelevant for matching constraints.  */
                      if (UNARY_P (op1))
                        op1 = XEXP (op1, 0);
                      if (UNARY_P (op2))
                        op2 = XEXP (op2, 0);

                      val = operands_match_p (op1, op2);
                    }

                  matching_operands[opno] = match;
                  matching_operands[match] = opno;

                  if (val != 0)
                    win = 1;

                  /* If output is *x and input is *--x, arrange later
                     to change the output to *--x as well, since the
                     output op is the one that will be printed.  */
                  if (val == 2 && strict > 0)
                    {
                      funny_match[funny_match_index].this_op = opno;
                      funny_match[funny_match_index++].other = match;
                    }
                }
                len = 0;
                break;

              case 'p':
                /* p is used for address_operands.  When we are called by
                   gen_reload, no one will have checked that the address is
                   strictly valid, i.e., that all pseudos requiring hard regs
                   have gotten them.  */
                if (strict <= 0
                    || (strict_memory_address_p (recog_data.operand_mode[opno],
                                                 op)))
                  win = 1;
                break;

                /* No need to check general_operand again;
                   it was done in insn-recog.c.  Well, except that reload
                   doesn't check the validity of its replacements, but
                   that should only matter when there's a bug.  */
              case 'g':
                /* Anything goes unless it is a REG and really has a hard reg
                   but the hard reg is not in the class GENERAL_REGS.  */
                if (REG_P (op))
                  {
                    if (strict < 0
                        || GENERAL_REGS == ALL_REGS
                        || (reload_in_progress
                            && REGNO (op) >= FIRST_PSEUDO_REGISTER)
                        || reg_fits_class_p (op, GENERAL_REGS, offset, mode))
                      win = 1;
                  }
                else if (strict < 0 || general_operand (op, mode))
                  win = 1;
                break;

              case 'X':
                /* This is used for a MATCH_SCRATCH in the cases when
                   we don't actually need anything.  So anything goes
                   any time.  */
                win = 1;
                break;

              case TARGET_MEM_CONSTRAINT:
                /* Memory operands must be valid, to the extent
                   required by STRICT.  */
                if (MEM_P (op))
                  {
                    if (strict > 0
                        && !strict_memory_address_addr_space_p
                             (GET_MODE (op), XEXP (op, 0),
                              MEM_ADDR_SPACE (op)))
                      break;
                    if (strict == 0
                        && !memory_address_addr_space_p
                             (GET_MODE (op), XEXP (op, 0),
                              MEM_ADDR_SPACE (op)))
                      break;
                    win = 1;
                  }
                /* Before reload, accept what reload can turn into mem.  */
                else if (strict < 0 && CONSTANT_P (op))
                  win = 1;
                /* During reload, accept a pseudo  */
                else if (reload_in_progress && REG_P (op)
                         && REGNO (op) >= FIRST_PSEUDO_REGISTER)
                  win = 1;
                break;

              case '<':
                if (MEM_P (op)
                    && (GET_CODE (XEXP (op, 0)) == PRE_DEC
                        || GET_CODE (XEXP (op, 0)) == POST_DEC))
                  win = 1;
                break;

              case '>':
                if (MEM_P (op)
                    && (GET_CODE (XEXP (op, 0)) == PRE_INC
                        || GET_CODE (XEXP (op, 0)) == POST_INC))
                  win = 1;
                break;

              case 'E':
              case 'F':
                if (CONST_DOUBLE_AS_FLOAT_P (op)
                    || (GET_CODE (op) == CONST_VECTOR
                        && GET_MODE_CLASS (GET_MODE (op)) == MODE_VECTOR_FLOAT))
                  win = 1;
                break;

              case 'G':
              case 'H':
                if (CONST_DOUBLE_AS_FLOAT_P (op)
                    && CONST_DOUBLE_OK_FOR_CONSTRAINT_P (op, c, p))
                  win = 1;
                break;

              case 's':
                if (CONST_SCALAR_INT_P (op))
                  break;
              case 'i':
                if (CONSTANT_P (op))
                  win = 1;
                break;

              case 'n':
                if (CONST_SCALAR_INT_P (op))
                  win = 1;
                break;

              case 'I':
              case 'J':
              case 'K':
              case 'L':
              case 'M':
              case 'N':
              case 'O':
              case 'P':
                if (CONST_INT_P (op)
                    && CONST_OK_FOR_CONSTRAINT_P (INTVAL (op), c, p))
                  win = 1;
                break;

              case 'V':
                if (MEM_P (op)
                    && ((strict > 0 && ! offsettable_memref_p (op))
                        || (strict < 0
                            && !(CONSTANT_P (op) || MEM_P (op)))
                        || (reload_in_progress
                            && !(REG_P (op)
                                 && REGNO (op) >= FIRST_PSEUDO_REGISTER))))
                  win = 1;
                break;

              case 'o':
                if ((strict > 0 && offsettable_memref_p (op))
                    || (strict == 0 && offsettable_nonstrict_memref_p (op))
                    /* Before reload, accept what reload can handle.  */
                    || (strict < 0
                        && (CONSTANT_P (op) || MEM_P (op)))
                    /* During reload, accept a pseudo  */
                    || (reload_in_progress && REG_P (op)
                        && REGNO (op) >= FIRST_PSEUDO_REGISTER))
                  win = 1;
                break;

              default:
                {
                  enum reg_class cl;

                  cl = (c == 'r'
                           ? GENERAL_REGS : REG_CLASS_FROM_CONSTRAINT (c, p));
                  if (cl != NO_REGS)
                    {
                      if (strict < 0
                          || (strict == 0
                              && REG_P (op)
                              && REGNO (op) >= FIRST_PSEUDO_REGISTER)
                          || (strict == 0 && GET_CODE (op) == SCRATCH)
                          || (REG_P (op)
                              && reg_fits_class_p (op, cl, offset, mode)))
                        win = 1;
                    }
#ifdef EXTRA_CONSTRAINT_STR
                  else if (EXTRA_CONSTRAINT_STR (op, c, p))
                    win = 1;

                  else if (EXTRA_MEMORY_CONSTRAINT (c, p)
                           /* Every memory operand can be reloaded to fit.  */
                           && ((strict < 0 && MEM_P (op))
                               /* Before reload, accept what reload can turn
                                  into mem.  */
                               || (strict < 0 && CONSTANT_P (op))
                               /* During reload, accept a pseudo  */
                               || (reload_in_progress && REG_P (op)
                                   && REGNO (op) >= FIRST_PSEUDO_REGISTER)))
                    win = 1;
                  else if (EXTRA_ADDRESS_CONSTRAINT (c, p)
                           /* Every address operand can be reloaded to fit.  */
                           && strict < 0)
                    win = 1;
                  /* Cater to architectures like IA-64 that define extra memory
                     constraints without using define_memory_constraint.  */
                  else if (reload_in_progress
                           && REG_P (op)
                           && REGNO (op) >= FIRST_PSEUDO_REGISTER
                           && reg_renumber[REGNO (op)] < 0
                           && reg_equiv_mem (REGNO (op)) != 0
                           && EXTRA_CONSTRAINT_STR
                              (reg_equiv_mem (REGNO (op)), c, p))
                    win = 1;
#endif
                  break;
                }
              }
          while (p += len, c);

          constraints[opno] = p;
          /* If this operand did not win somehow,
             this alternative loses.  */
          if (! win)
            lose = 1;
        }
      /* This alternative won; the operands are ok.
         Change whichever operands this alternative says to change.  */
      if (! lose)
        {
          int opno, eopno;

          /* See if any earlyclobber operand conflicts with some other
             operand.  */

          if (strict > 0  && seen_earlyclobber_at >= 0)
            for (eopno = seen_earlyclobber_at;
                 eopno < recog_data.n_operands;
                 eopno++)
              /* Ignore earlyclobber operands now in memory,
                 because we would often report failure when we have
                 two memory operands, one of which was formerly a REG.  */
              if (earlyclobber[eopno]
                  && REG_P (recog_data.operand[eopno]))
                for (opno = 0; opno < recog_data.n_operands; opno++)
                  if ((MEM_P (recog_data.operand[opno])
                       || recog_data.operand_type[opno] != OP_OUT)
                      && opno != eopno
                      /* Ignore things like match_operator operands.  */
                      && *recog_data.constraints[opno] != 0
                      && ! (matching_operands[opno] == eopno
                            && operands_match_p (recog_data.operand[opno],
                                                 recog_data.operand[eopno]))
                      && ! safe_from_earlyclobber (recog_data.operand[opno],
                                                   recog_data.operand[eopno]))
                    lose = 1;

          if (! lose)
            {
              while (--funny_match_index >= 0)
                {
                  recog_data.operand[funny_match[funny_match_index].other]
                    = recog_data.operand[funny_match[funny_match_index].this_op];
                }

#ifdef AUTO_INC_DEC
              /* For operands without < or > constraints reject side-effects.  */
              if (recog_data.is_asm)
                {
                  for (opno = 0; opno < recog_data.n_operands; opno++)
                    if (MEM_P (recog_data.operand[opno]))
                      switch (GET_CODE (XEXP (recog_data.operand[opno], 0)))
                        {
                        case PRE_INC:
                        case POST_INC:
                        case PRE_DEC:
                        case POST_DEC:
                        case PRE_MODIFY:
                        case POST_MODIFY:
                          if (strchr (recog_data.constraints[opno], '<') == NULL
                              && strchr (recog_data.constraints[opno], '>')
                                 == NULL)
                            return 0;
                          break;
                        default:
                          break;
                        }
                }
#endif
              return 1;
            }
        }

      which_alternative++;
    }
  while (which_alternative < recog_data.n_alternatives);

  which_alternative = -1;
  /* If we are about to reject this, but we are not to test strictly,
     try a very loose test.  Only return failure if it fails also.  */
  if (strict == 0)
    return constrain_operands (-1);
  else
    return 0;
}

/* Return true iff OPERAND (assumed to be a REG rtx)
   is a hard reg in class CLASS when its regno is offset by OFFSET
   and changed to mode MODE.
   If REG occupies multiple hard regs, all of them must be in CLASS.  */

bool
reg_fits_class_p (const_rtx operand, reg_class_t cl, int offset,
                  enum machine_mode mode)
{
  unsigned int regno = REGNO (operand);

  if (cl == NO_REGS)
    return false;

  /* Regno must not be a pseudo register.  Offset may be negative.  */
  return (HARD_REGISTER_NUM_P (regno)
          && HARD_REGISTER_NUM_P (regno + offset)
          && in_hard_reg_set_p (reg_class_contents[(int) cl], mode, 
                                regno + offset));
}
\f
/* Split single instruction.  Helper function for split_all_insns and
   split_all_insns_noflow.  Return last insn in the sequence if successful,
   or NULL if unsuccessful.  */

static rtx
split_insn (rtx insn)
{
  /* Split insns here to get max fine-grain parallelism.  */
  rtx first = PREV_INSN (insn);
  rtx last = try_split (PATTERN (insn), insn, 1);
  rtx insn_set, last_set, note;

  if (last == insn)
    return NULL_RTX;

  /* If the original instruction was a single set that was known to be
     equivalent to a constant, see if we can say the same about the last
     instruction in the split sequence.  The two instructions must set
     the same destination.  */
  insn_set = single_set (insn);
  if (insn_set)
    {
      last_set = single_set (last);
      if (last_set && rtx_equal_p (SET_DEST (last_set), SET_DEST (insn_set)))
        {
          note = find_reg_equal_equiv_note (insn);
          if (note && CONSTANT_P (XEXP (note, 0)))
            set_unique_reg_note (last, REG_EQUAL, XEXP (note, 0));
          else if (CONSTANT_P (SET_SRC (insn_set)))
            set_unique_reg_note (last, REG_EQUAL,
                                 copy_rtx (SET_SRC (insn_set)));
        }
    }

  /* try_split returns the NOTE that INSN became.  */
  SET_INSN_DELETED (insn);

  /* ??? Coddle to md files that generate subregs in post-reload
     splitters instead of computing the proper hard register.  */
  if (reload_completed && first != last)
    {
      first = NEXT_INSN (first);
      for (;;)
        {
          if (INSN_P (first))
            cleanup_subreg_operands (first);
          if (first == last)
            break;
          first = NEXT_INSN (first);
        }
    }

  return last;
}

/* Split all insns in the function.  If UPD_LIFE, update life info after.  */

void
split_all_insns (void)
{
  sbitmap blocks;
  bool changed;
  basic_block bb;

  blocks = sbitmap_alloc (last_basic_block);
  bitmap_clear (blocks);
  changed = false;

  FOR_EACH_BB_REVERSE (bb)
    {
      rtx insn, next;
      bool finish = false;

      rtl_profile_for_bb (bb);
      for (insn = BB_HEAD (bb); !finish ; insn = next)
        {
          /* Can't use `next_real_insn' because that might go across
             CODE_LABELS and short-out basic blocks.  */
          next = NEXT_INSN (insn);
          finish = (insn == BB_END (bb));
          if (INSN_P (insn))
            {
              rtx set = single_set (insn);

              /* Don't split no-op move insns.  These should silently
                 disappear later in final.  Splitting such insns would
                 break the code that handles LIBCALL blocks.  */
              if (set && set_noop_p (set))
                {
                  /* Nops get in the way while scheduling, so delete them
                     now if register allocation has already been done.  It
                     is too risky to try to do this before register
                     allocation, and there are unlikely to be very many
                     nops then anyways.  */
                  if (reload_completed)
                      delete_insn_and_edges (insn);
                }
              else
                {
                  if (split_insn (insn))
                    {
                      bitmap_set_bit (blocks, bb->index);
                      changed = true;
                    }
                }
            }
        }
    }

  default_rtl_profile ();
  if (changed)
    find_many_sub_basic_blocks (blocks);

#ifdef ENABLE_CHECKING
  verify_flow_info ();
#endif

  sbitmap_free (blocks);
}

/* Same as split_all_insns, but do not expect CFG to be available.
   Used by machine dependent reorg passes.  */

unsigned int
split_all_insns_noflow (void)
{
  rtx next, insn;

  for (insn = get_insns (); insn; insn = next)
    {
      next = NEXT_INSN (insn);
      if (INSN_P (insn))
        {
          /* Don't split no-op move insns.  These should silently
             disappear later in final.  Splitting such insns would
             break the code that handles LIBCALL blocks.  */
          rtx set = single_set (insn);
          if (set && set_noop_p (set))
            {
              /* Nops get in the way while scheduling, so delete them
                 now if register allocation has already been done.  It
                 is too risky to try to do this before register
                 allocation, and there are unlikely to be very many
                 nops then anyways.

                 ??? Should we use delete_insn when the CFG isn't valid?  */
              if (reload_completed)
                delete_insn_and_edges (insn);
            }
          else
            split_insn (insn);
        }
    }
  return 0;
}
\f
#ifdef HAVE_peephole2
struct peep2_insn_data
{
  rtx insn;
  regset live_before;
};

static struct peep2_insn_data peep2_insn_data[MAX_INSNS_PER_PEEP2 + 1];
static int peep2_current;

static bool peep2_do_rebuild_jump_labels;
static bool peep2_do_cleanup_cfg;

/* The number of instructions available to match a peep2.  */
int peep2_current_count;

/* A non-insn marker indicating the last insn of the block.
   The live_before regset for this element is correct, indicating
   DF_LIVE_OUT for the block.  */
#define PEEP2_EOB       pc_rtx

/* Wrap N to fit into the peep2_insn_data buffer.  */

static int
peep2_buf_position (int n)
{
  if (n >= MAX_INSNS_PER_PEEP2 + 1)
    n -= MAX_INSNS_PER_PEEP2 + 1;
  return n;
}

/* Return the Nth non-note insn after `current', or return NULL_RTX if it
   does not exist.  Used by the recognizer to find the next insn to match
   in a multi-insn pattern.  */

rtx
peep2_next_insn (int n)
{
  gcc_assert (n <= peep2_current_count);

  n = peep2_buf_position (peep2_current + n);

  return peep2_insn_data[n].insn;
}

/* Return true if REGNO is dead before the Nth non-note insn
   after `current'.  */

int
peep2_regno_dead_p (int ofs, int regno)
{
  gcc_assert (ofs < MAX_INSNS_PER_PEEP2 + 1);

  ofs = peep2_buf_position (peep2_current + ofs);

  gcc_assert (peep2_insn_data[ofs].insn != NULL_RTX);

  return ! REGNO_REG_SET_P (peep2_insn_data[ofs].live_before, regno);
}

/* Similarly for a REG.  */

int
peep2_reg_dead_p (int ofs, rtx reg)
{
  int regno, n;

  gcc_assert (ofs < MAX_INSNS_PER_PEEP2 + 1);

  ofs = peep2_buf_position (peep2_current + ofs);

  gcc_assert (peep2_insn_data[ofs].insn != NULL_RTX);

  regno = REGNO (reg);
  n = hard_regno_nregs[regno][GET_MODE (reg)];
  while (--n >= 0)
    if (REGNO_REG_SET_P (peep2_insn_data[ofs].live_before, regno + n))
      return 0;
  return 1;
}

/* Try to find a hard register of mode MODE, matching the register class in
   CLASS_STR, which is available at the beginning of insn CURRENT_INSN and
   remains available until the end of LAST_INSN.  LAST_INSN may be NULL_RTX,
   in which case the only condition is that the register must be available
   before CURRENT_INSN.
   Registers that already have bits set in REG_SET will not be considered.

   If an appropriate register is available, it will be returned and the
   corresponding bit(s) in REG_SET will be set; otherwise, NULL_RTX is
   returned.  */

rtx
peep2_find_free_register (int from, int to, const char *class_str,
                          enum machine_mode mode, HARD_REG_SET *reg_set)
{
  static int search_ofs;
  enum reg_class cl;
  HARD_REG_SET live;
  df_ref *def_rec;
  int i;

  gcc_assert (from < MAX_INSNS_PER_PEEP2 + 1);
  gcc_assert (to < MAX_INSNS_PER_PEEP2 + 1);

  from = peep2_buf_position (peep2_current + from);
  to = peep2_buf_position (peep2_current + to);

  gcc_assert (peep2_insn_data[from].insn != NULL_RTX);
  REG_SET_TO_HARD_REG_SET (live, peep2_insn_data[from].live_before);

  while (from != to)
    {
      gcc_assert (peep2_insn_data[from].insn != NULL_RTX);

      /* Don't use registers set or clobbered by the insn.  */
      for (def_rec = DF_INSN_DEFS (peep2_insn_data[from].insn);
           *def_rec; def_rec++)
        SET_HARD_REG_BIT (live, DF_REF_REGNO (*def_rec));

      from = peep2_buf_position (from + 1);
    }

  cl = (class_str[0] == 'r' ? GENERAL_REGS
           : REG_CLASS_FROM_CONSTRAINT (class_str[0], class_str));

  for (i = 0; i < FIRST_PSEUDO_REGISTER; i++)
    {
      int raw_regno, regno, success, j;

      /* Distribute the free registers as much as possible.  */
      raw_regno = search_ofs + i;
      if (raw_regno >= FIRST_PSEUDO_REGISTER)
        raw_regno -= FIRST_PSEUDO_REGISTER;
#ifdef REG_ALLOC_ORDER
      regno = reg_alloc_order[raw_regno];
#else
      regno = raw_regno;
#endif

      /* Can it support the mode we need?  */
      if (! HARD_REGNO_MODE_OK (regno, mode))
        continue;

      success = 1;
      for (j = 0; success && j < hard_regno_nregs[regno][mode]; j++)
        {
          /* Don't allocate fixed registers.  */
          if (fixed_regs[regno + j])
            {
              success = 0;
              break;
            }
          /* Don't allocate global registers.  */
          if (global_regs[regno + j])
            {
              success = 0;
              break;
            }
          /* Make sure the register is of the right class.  */
          if (! TEST_HARD_REG_BIT (reg_class_contents[cl], regno + j))
            {
              success = 0;
              break;
            }
          /* And that we don't create an extra save/restore.  */
          if (! call_used_regs[regno + j] && ! df_regs_ever_live_p (regno + j))
            {
              success = 0;
              break;
            }

          if (! targetm.hard_regno_scratch_ok (regno + j))
            {
              success = 0;
              break;
            }

          /* And we don't clobber traceback for noreturn functions.  */
          if ((regno + j == FRAME_POINTER_REGNUM
               || regno + j == HARD_FRAME_POINTER_REGNUM)
              && (! reload_completed || frame_pointer_needed))
            {
              success = 0;
              break;
            }

          if (TEST_HARD_REG_BIT (*reg_set, regno + j)
              || TEST_HARD_REG_BIT (live, regno + j))
            {
              success = 0;
              break;
            }
        }

      if (success)
        {
          add_to_hard_reg_set (reg_set, mode, regno);

          /* Start the next search with the next register.  */
          if (++raw_regno >= FIRST_PSEUDO_REGISTER)
            raw_regno = 0;
          search_ofs = raw_regno;

          return gen_rtx_REG (mode, regno);
        }
    }

  search_ofs = 0;
  return NULL_RTX;
}

/* Forget all currently tracked instructions, only remember current
   LIVE regset.  */

static void
peep2_reinit_state (regset live)
{
  int i;

  /* Indicate that all slots except the last holds invalid data.  */
  for (i = 0; i < MAX_INSNS_PER_PEEP2; ++i)
    peep2_insn_data[i].insn = NULL_RTX;
  peep2_current_count = 0;

  /* Indicate that the last slot contains live_after data.  */
  peep2_insn_data[MAX_INSNS_PER_PEEP2].insn = PEEP2_EOB;
  peep2_current = MAX_INSNS_PER_PEEP2;

  COPY_REG_SET (peep2_insn_data[MAX_INSNS_PER_PEEP2].live_before, live);
}

/* While scanning basic block BB, we found a match of length MATCH_LEN,
   starting at INSN.  Perform the replacement, removing the old insns and
   replacing them with ATTEMPT.  Returns the last insn emitted, or NULL
   if the replacement is rejected.  */

static rtx
peep2_attempt (basic_block bb, rtx insn, int match_len, rtx attempt)
{
  int i;
  rtx last, eh_note, as_note, before_try, x;
  rtx old_insn, new_insn;
  bool was_call = false;

  /* If we are splitting an RTX_FRAME_RELATED_P insn, do not allow it to
     match more than one insn, or to be split into more than one insn.  */
  old_insn = peep2_insn_data[peep2_current].insn;
  if (RTX_FRAME_RELATED_P (old_insn))
    {
      bool any_note = false;
      rtx note;

      if (match_len != 0)
        return NULL;

      /* Look for one "active" insn.  I.e. ignore any "clobber" insns that
         may be in the stream for the purpose of register allocation.  */
      if (active_insn_p (attempt))
        new_insn = attempt;
      else
        new_insn = next_active_insn (attempt);
      if (next_active_insn (new_insn))
        return NULL;

      /* We have a 1-1 replacement.  Copy over any frame-related info.  */
      RTX_FRAME_RELATED_P (new_insn) = 1;

      /* Allow the backend to fill in a note during the split.  */
      for (note = REG_NOTES (new_insn); note ; note = XEXP (note, 1))
        switch (REG_NOTE_KIND (note))
          {
          case REG_FRAME_RELATED_EXPR:
          case REG_CFA_DEF_CFA:
          case REG_CFA_ADJUST_CFA:
          case REG_CFA_OFFSET:
          case REG_CFA_REGISTER:
          case REG_CFA_EXPRESSION:
          case REG_CFA_RESTORE:
          case REG_CFA_SET_VDRAP:
            any_note = true;
            break;
          default:
            break;
          }

      /* If the backend didn't supply a note, copy one over.  */
      if (!any_note)
        for (note = REG_NOTES (old_insn); note ; note = XEXP (note, 1))
          switch (REG_NOTE_KIND (note))
            {
            case REG_FRAME_RELATED_EXPR:
            case REG_CFA_DEF_CFA:
            case REG_CFA_ADJUST_CFA:
            case REG_CFA_OFFSET:
            case REG_CFA_REGISTER:
            case REG_CFA_EXPRESSION:
            case REG_CFA_RESTORE:
            case REG_CFA_SET_VDRAP:
              add_reg_note (new_insn, REG_NOTE_KIND (note), XEXP (note, 0));
              any_note = true;
              break;
            default:
              break;
            }

      /* If there still isn't a note, make sure the unwind info sees the
         same expression as before the split.  */
      if (!any_note)
        {
          rtx old_set, new_set;

          /* The old insn had better have been simple, or annotated.  */
          old_set = single_set (old_insn);
          gcc_assert (old_set != NULL);

          new_set = single_set (new_insn);
          if (!new_set || !rtx_equal_p (new_set, old_set))
            add_reg_note (new_insn, REG_FRAME_RELATED_EXPR, old_set);
        }

      /* Copy prologue/epilogue status.  This is required in order to keep
         proper placement of EPILOGUE_BEG and the DW_CFA_remember_state.  */
      maybe_copy_prologue_epilogue_insn (old_insn, new_insn);
    }

  /* If we are splitting a CALL_INSN, look for the CALL_INSN
     in SEQ and copy our CALL_INSN_FUNCTION_USAGE and other
     cfg-related call notes.  */
  for (i = 0; i <= match_len; ++i)
    {
      int j;
      rtx note;

      j = peep2_buf_position (peep2_current + i);
      old_insn = peep2_insn_data[j].insn;
      if (!CALL_P (old_insn))
        continue;
      was_call = true;

      new_insn = attempt;
      while (new_insn != NULL_RTX)
        {
          if (CALL_P (new_insn))
            break;
          new_insn = NEXT_INSN (new_insn);
        }

      gcc_assert (new_insn != NULL_RTX);

      CALL_INSN_FUNCTION_USAGE (new_insn)
        = CALL_INSN_FUNCTION_USAGE (old_insn);

      for (note = REG_NOTES (old_insn);
           note;
           note = XEXP (note, 1))
        switch (REG_NOTE_KIND (note))
          {
          case REG_NORETURN:
          case REG_SETJMP:
          case REG_TM:
            add_reg_note (new_insn, REG_NOTE_KIND (note),
                          XEXP (note, 0));
            break;
          default:
            /* Discard all other reg notes.  */
            break;
          }

      /* Croak if there is another call in the sequence.  */
      while (++i <= match_len)
        {
          j = peep2_buf_position (peep2_current + i);
          old_insn = peep2_insn_data[j].insn;
          gcc_assert (!CALL_P (old_insn));
        }
      break;
    }

  /* If we matched any instruction that had a REG_ARGS_SIZE, then
     move those notes over to the new sequence.  */
  as_note = NULL;
  for (i = match_len; i >= 0; --i)
    {
      int j = peep2_buf_position (peep2_current + i);
      old_insn = peep2_insn_data[j].insn;

      as_note = find_reg_note (old_insn, REG_ARGS_SIZE, NULL);
      if (as_note)
        break;
    }

  i = peep2_buf_position (peep2_current + match_len);
  eh_note = find_reg_note (peep2_insn_data[i].insn, REG_EH_REGION, NULL_RTX);

  /* Replace the old sequence with the new.  */
  last = emit_insn_after_setloc (attempt,
                                 peep2_insn_data[i].insn,
                                 INSN_LOCATION (peep2_insn_data[i].insn));
  before_try = PREV_INSN (insn);
  delete_insn_chain (insn, peep2_insn_data[i].insn, false);

  /* Re-insert the EH_REGION notes.  */
  if (eh_note || (was_call && nonlocal_goto_handler_labels))
    {
      edge eh_edge;
      edge_iterator ei;

      FOR_EACH_EDGE (eh_edge, ei, bb->succs)
        if (eh_edge->flags & (EDGE_EH | EDGE_ABNORMAL_CALL))
          break;

      if (eh_note)
        copy_reg_eh_region_note_backward (eh_note, last, before_try);

      if (eh_edge)
        for (x = last; x != before_try; x = PREV_INSN (x))
          if (x != BB_END (bb)
              && (can_throw_internal (x)
                  || can_nonlocal_goto (x)))
            {
              edge nfte, nehe;
              int flags;

              nfte = split_block (bb, x);
              flags = (eh_edge->flags
                       & (EDGE_EH | EDGE_ABNORMAL));
              if (CALL_P (x))
                flags |= EDGE_ABNORMAL_CALL;
              nehe = make_edge (nfte->src, eh_edge->dest,
                                flags);

              nehe->probability = eh_edge->probability;
              nfte->probability
                = REG_BR_PROB_BASE - nehe->probability;

              peep2_do_cleanup_cfg |= purge_dead_edges (nfte->dest);
              bb = nfte->src;
              eh_edge = nehe;
            }

      /* Converting possibly trapping insn to non-trapping is
         possible.  Zap dummy outgoing edges.  */
      peep2_do_cleanup_cfg |= purge_dead_edges (bb);
    }

  /* Re-insert the ARGS_SIZE notes.  */
  if (as_note)
    fixup_args_size_notes (before_try, last, INTVAL (XEXP (as_note, 0)));

  /* If we generated a jump instruction, it won't have
     JUMP_LABEL set.  Recompute after we're done.  */
  for (x = last; x != before_try; x = PREV_INSN (x))
    if (JUMP_P (x))
      {
        peep2_do_rebuild_jump_labels = true;
        break;
      }

  return last;
}

/* After performing a replacement in basic block BB, fix up the life
   information in our buffer.  LAST is the last of the insns that we
   emitted as a replacement.  PREV is the insn before the start of
   the replacement.  MATCH_LEN is the number of instructions that were
   matched, and which now need to be replaced in the buffer.  */

static void
peep2_update_life (basic_block bb, int match_len, rtx last, rtx prev)
{
  int i = peep2_buf_position (peep2_current + match_len + 1);
  rtx x;
  regset_head live;

  INIT_REG_SET (&live);
  COPY_REG_SET (&live, peep2_insn_data[i].live_before);

  gcc_assert (peep2_current_count >= match_len + 1);
  peep2_current_count -= match_len + 1;

  x = last;
  do
    {
      if (INSN_P (x))
        {
          df_insn_rescan (x);
          if (peep2_current_count < MAX_INSNS_PER_PEEP2)
            {
              peep2_current_count++;
              if (--i < 0)
                i = MAX_INSNS_PER_PEEP2;
              peep2_insn_data[i].insn = x;
              df_simulate_one_insn_backwards (bb, x, &live);
              COPY_REG_SET (peep2_insn_data[i].live_before, &live);
            }
        }
      x = PREV_INSN (x);
    }
  while (x != prev);
  CLEAR_REG_SET (&live);

  peep2_current = i;
}

/* Add INSN, which is in BB, at the end of the peep2 insn buffer if possible.
   Return true if we added it, false otherwise.  The caller will try to match
   peepholes against the buffer if we return false; otherwise it will try to
   add more instructions to the buffer.  */

static bool
peep2_fill_buffer (basic_block bb, rtx insn, regset live)
{
  int pos;

  /* Once we have filled the maximum number of insns the buffer can hold,
     allow the caller to match the insns against peepholes.  We wait until
     the buffer is full in case the target has similar peepholes of different
     length; we always want to match the longest if possible.  */
  if (peep2_current_count == MAX_INSNS_PER_PEEP2)
    return false;

  /* If an insn has RTX_FRAME_RELATED_P set, do not allow it to be matched with
     any other pattern, lest it change the semantics of the frame info.  */
  if (RTX_FRAME_RELATED_P (insn))
    {
      /* Let the buffer drain first.  */
      if (peep2_current_count > 0)
        return false;
      /* Now the insn will be the only thing in the buffer.  */
    }

  pos = peep2_buf_position (peep2_current + peep2_current_count);
  peep2_insn_data[pos].insn = insn;
  COPY_REG_SET (peep2_insn_data[pos].live_before, live);
  peep2_current_count++;

  df_simulate_one_insn_forwards (bb, insn, live);
  return true;
}

/* Perform the peephole2 optimization pass.  */

static void
peephole2_optimize (void)
{
  rtx insn;
  bitmap live;
  int i;
  basic_block bb;

  peep2_do_cleanup_cfg = false;
  peep2_do_rebuild_jump_labels = false;

  df_set_flags (DF_LR_RUN_DCE);
  df_note_add_problem ();
  df_analyze ();

  /* Initialize the regsets we're going to use.  */
  for (i = 0; i < MAX_INSNS_PER_PEEP2 + 1; ++i)
    peep2_insn_data[i].live_before = BITMAP_ALLOC (&reg_obstack);
  live = BITMAP_ALLOC (&reg_obstack);

  FOR_EACH_BB_REVERSE (bb)
    {
      bool past_end = false;
      int pos;

      rtl_profile_for_bb (bb);

      /* Start up propagation.  */
      bitmap_copy (live, DF_LR_IN (bb));
      df_simulate_initialize_forwards (bb, live);
      peep2_reinit_state (live);

      insn = BB_HEAD (bb);
      for (;;)
        {
          rtx attempt, head;
          int match_len;

          if (!past_end && !NONDEBUG_INSN_P (insn))
            {
            next_insn:
              insn = NEXT_INSN (insn);
              if (insn == NEXT_INSN (BB_END (bb)))
                past_end = true;
              continue;
            }
          if (!past_end && peep2_fill_buffer (bb, insn, live))
            goto next_insn;

          /* If we did not fill an empty buffer, it signals the end of the
             block.  */
          if (peep2_current_count == 0)
            break;

          /* The buffer filled to the current maximum, so try to match.  */

          pos = peep2_buf_position (peep2_current + peep2_current_count);
          peep2_insn_data[pos].insn = PEEP2_EOB;
          COPY_REG_SET (peep2_insn_data[pos].live_before, live);

          /* Match the peephole.  */
          head = peep2_insn_data[peep2_current].insn;
          attempt = peephole2_insns (PATTERN (head), head, &match_len);
          if (attempt != NULL)
            {
              rtx last = peep2_attempt (bb, head, match_len, attempt);
              if (last)
                {
                  peep2_update_life (bb, match_len, last, PREV_INSN (attempt));
                  continue;
                }
            }

          /* No match: advance the buffer by one insn.  */
          peep2_current = peep2_buf_position (peep2_current + 1);
          peep2_current_count--;
        }
    }

  default_rtl_profile ();
  for (i = 0; i < MAX_INSNS_PER_PEEP2 + 1; ++i)
    BITMAP_FREE (peep2_insn_data[i].live_before);
  BITMAP_FREE (live);
  if (peep2_do_rebuild_jump_labels)
    rebuild_jump_labels (get_insns ());
}
#endif /* HAVE_peephole2 */

/* Common predicates for use with define_bypass.  */

/* True if the dependency between OUT_INSN and IN_INSN is on the store
   data not the address operand(s) of the store.  IN_INSN and OUT_INSN
   must be either a single_set or a PARALLEL with SETs inside.  */

int
store_data_bypass_p (rtx out_insn, rtx in_insn)
{
  rtx out_set, in_set;
  rtx out_pat, in_pat;
  rtx out_exp, in_exp;
  int i, j;

  in_set = single_set (in_insn);
  if (in_set)
    {
      if (!MEM_P (SET_DEST (in_set)))
        return false;

      out_set = single_set (out_insn);
      if (out_set)
        {
          if (reg_mentioned_p (SET_DEST (out_set), SET_DEST (in_set)))
            return false;
        }
      else
        {
          out_pat = PATTERN (out_insn);

          if (GET_CODE (out_pat) != PARALLEL)
            return false;

          for (i = 0; i < XVECLEN (out_pat, 0); i++)
          {
            out_exp = XVECEXP (out_pat, 0, i);

            if (GET_CODE (out_exp) == CLOBBER)
              continue;

            gcc_assert (GET_CODE (out_exp) == SET);

            if (reg_mentioned_p (SET_DEST (out_exp), SET_DEST (in_set)))
              return false;
          }
      }
    }
  else
    {
      in_pat = PATTERN (in_insn);
      gcc_assert (GET_CODE (in_pat) == PARALLEL);

      for (i = 0; i < XVECLEN (in_pat, 0); i++)
        {
          in_exp = XVECEXP (in_pat, 0, i);

          if (GET_CODE (in_exp) == CLOBBER)
            continue;

          gcc_assert (GET_CODE (in_exp) == SET);

          if (!MEM_P (SET_DEST (in_exp)))
            return false;

          out_set = single_set (out_insn);
          if (out_set)
            {
              if (reg_mentioned_p (SET_DEST (out_set), SET_DEST (in_exp)))
                return false;
            }
          else
            {
              out_pat = PATTERN (out_insn);
              gcc_assert (GET_CODE (out_pat) == PARALLEL);

              for (j = 0; j < XVECLEN (out_pat, 0); j++)
                {
                  out_exp = XVECEXP (out_pat, 0, j);

                  if (GET_CODE (out_exp) == CLOBBER)
                    continue;

                  gcc_assert (GET_CODE (out_exp) == SET);

                  if (reg_mentioned_p (SET_DEST (out_exp), SET_DEST (in_exp)))
                    return false;
                }
            }
        }
    }

  return true;
}

/* True if the dependency between OUT_INSN and IN_INSN is in the IF_THEN_ELSE
   condition, and not the THEN or ELSE branch.  OUT_INSN may be either a single
   or multiple set; IN_INSN should be single_set for truth, but for convenience
   of insn categorization may be any JUMP or CALL insn.  */

int
if_test_bypass_p (rtx out_insn, rtx in_insn)
{
  rtx out_set, in_set;

  in_set = single_set (in_insn);
  if (! in_set)
    {
      gcc_assert (JUMP_P (in_insn) || CALL_P (in_insn));
      return false;
    }

  if (GET_CODE (SET_SRC (in_set)) != IF_THEN_ELSE)
    return false;
  in_set = SET_SRC (in_set);

  out_set = single_set (out_insn);
  if (out_set)
    {
      if (reg_mentioned_p (SET_DEST (out_set), XEXP (in_set, 1))
          || reg_mentioned_p (SET_DEST (out_set), XEXP (in_set, 2)))
        return false;
    }
  else
    {
      rtx out_pat;
      int i;

      out_pat = PATTERN (out_insn);
      gcc_assert (GET_CODE (out_pat) == PARALLEL);

      for (i = 0; i < XVECLEN (out_pat, 0); i++)
        {
          rtx exp = XVECEXP (out_pat, 0, i);

          if (GET_CODE (exp) == CLOBBER)
            continue;

          gcc_assert (GET_CODE (exp) == SET);

          if (reg_mentioned_p (SET_DEST (out_set), XEXP (in_set, 1))
              || reg_mentioned_p (SET_DEST (out_set), XEXP (in_set, 2)))
            return false;
        }
    }

  return true;
}
\f
static bool
gate_handle_peephole2 (void)
{
  return (optimize > 0 && flag_peephole2);
}

static unsigned int
rest_of_handle_peephole2 (void)
{
#ifdef HAVE_peephole2
  peephole2_optimize ();
#endif
  return 0;
}

namespace {

const pass_data pass_data_peephole2 =
{
  RTL_PASS, /* type */
  "peephole2", /* name */
  OPTGROUP_NONE, /* optinfo_flags */
  true, /* has_gate */
  true, /* has_execute */
  TV_PEEPHOLE2, /* tv_id */
  0, /* properties_required */
  0, /* properties_provided */
  0, /* properties_destroyed */
  0, /* todo_flags_start */
  ( TODO_df_finish | TODO_verify_rtl_sharing | 0 ), /* todo_flags_finish */
};

class pass_peephole2 : public rtl_opt_pass
{
public:
  pass_peephole2 (gcc::context *ctxt)
    : rtl_opt_pass (pass_data_peephole2, ctxt)
  {}

  /* opt_pass methods: */
  /* The epiphany backend creates a second instance of this pass, so we need
     a clone method.  */
  opt_pass * clone () { return new pass_peephole2 (m_ctxt); }
  bool gate () { return gate_handle_peephole2 (); }
  unsigned int execute () { return rest_of_handle_peephole2 (); }

}; // class pass_peephole2

} // anon namespace

rtl_opt_pass *
make_pass_peephole2 (gcc::context *ctxt)
{
  return new pass_peephole2 (ctxt);
}

static unsigned int
rest_of_handle_split_all_insns (void)
{
  split_all_insns ();
  return 0;
}

namespace {

const pass_data pass_data_split_all_insns =
{
  RTL_PASS, /* type */
  "split1", /* name */
  OPTGROUP_NONE, /* optinfo_flags */
  false, /* has_gate */
  true, /* has_execute */
  TV_NONE, /* tv_id */
  0, /* properties_required */
  0, /* properties_provided */
  0, /* properties_destroyed */
  0, /* todo_flags_start */
  0, /* todo_flags_finish */
};

class pass_split_all_insns : public rtl_opt_pass
{
public:
  pass_split_all_insns (gcc::context *ctxt)
    : rtl_opt_pass (pass_data_split_all_insns, ctxt)
  {}

  /* opt_pass methods: */
  /* The epiphany backend creates a second instance of this pass, so
     we need a clone method.  */
  opt_pass * clone () { return new pass_split_all_insns (m_ctxt); }
  unsigned int execute () { return rest_of_handle_split_all_insns (); }

}; // class pass_split_all_insns

} // anon namespace

rtl_opt_pass *
make_pass_split_all_insns (gcc::context *ctxt)
{
  return new pass_split_all_insns (ctxt);
}

static unsigned int
rest_of_handle_split_after_reload (void)
{
  /* If optimizing, then go ahead and split insns now.  */
#ifndef STACK_REGS
  if (optimize > 0)
#endif
    split_all_insns ();
  return 0;
}

namespace {

const pass_data pass_data_split_after_reload =
{
  RTL_PASS, /* type */
  "split2", /* name */
  OPTGROUP_NONE, /* optinfo_flags */
  false, /* has_gate */
  true, /* has_execute */
  TV_NONE, /* tv_id */
  0, /* properties_required */
  0, /* properties_provided */
  0, /* properties_destroyed */
  0, /* todo_flags_start */
  0, /* todo_flags_finish */
};

class pass_split_after_reload : public rtl_opt_pass
{
public:
  pass_split_after_reload (gcc::context *ctxt)
    : rtl_opt_pass (pass_data_split_after_reload, ctxt)
  {}

  /* opt_pass methods: */
  unsigned int execute () { return rest_of_handle_split_after_reload (); }

}; // class pass_split_after_reload

} // anon namespace

rtl_opt_pass *
make_pass_split_after_reload (gcc::context *ctxt)
{
  return new pass_split_after_reload (ctxt);
}

static bool
gate_handle_split_before_regstack (void)
{
#if HAVE_ATTR_length && defined (STACK_REGS)
  /* If flow2 creates new instructions which need splitting
     and scheduling after reload is not done, they might not be
     split until final which doesn't allow splitting
     if HAVE_ATTR_length.  */
# ifdef INSN_SCHEDULING
  return (optimize && !flag_schedule_insns_after_reload);
# else
  return (optimize);
# endif
#else
  return 0;
#endif
}

static unsigned int
rest_of_handle_split_before_regstack (void)
{
  split_all_insns ();
  return 0;
}

namespace {

const pass_data pass_data_split_before_regstack =
{
  RTL_PASS, /* type */
  "split3", /* name */
  OPTGROUP_NONE, /* optinfo_flags */
  true, /* has_gate */
  true, /* has_execute */
  TV_NONE, /* tv_id */
  0, /* properties_required */
  0, /* properties_provided */
  0, /* properties_destroyed */
  0, /* todo_flags_start */
  0, /* todo_flags_finish */
};

class pass_split_before_regstack : public rtl_opt_pass
{
public:
  pass_split_before_regstack (gcc::context *ctxt)
    : rtl_opt_pass (pass_data_split_before_regstack, ctxt)
  {}

  /* opt_pass methods: */
  bool gate () { return gate_handle_split_before_regstack (); }
  unsigned int execute () {
    return rest_of_handle_split_before_regstack ();
  }

}; // class pass_split_before_regstack

} // anon namespace

rtl_opt_pass *
make_pass_split_before_regstack (gcc::context *ctxt)
{
  return new pass_split_before_regstack (ctxt);
}

static bool
gate_handle_split_before_sched2 (void)
{
#ifdef INSN_SCHEDULING
  return optimize > 0 && flag_schedule_insns_after_reload;
#else
  return 0;
#endif
}

static unsigned int
rest_of_handle_split_before_sched2 (void)
{
#ifdef INSN_SCHEDULING
  split_all_insns ();
#endif
  return 0;
}

namespace {

const pass_data pass_data_split_before_sched2 =
{
  RTL_PASS, /* type */
  "split4", /* name */
  OPTGROUP_NONE, /* optinfo_flags */
  true, /* has_gate */
  true, /* has_execute */
  TV_NONE, /* tv_id */
  0, /* properties_required */
  0, /* properties_provided */
  0, /* properties_destroyed */
  0, /* todo_flags_start */
  TODO_verify_flow, /* todo_flags_finish */
};

class pass_split_before_sched2 : public rtl_opt_pass
{
public:
  pass_split_before_sched2 (gcc::context *ctxt)
    : rtl_opt_pass (pass_data_split_before_sched2, ctxt)
  {}

  /* opt_pass methods: */
  bool gate () { return gate_handle_split_before_sched2 (); }
  unsigned int execute () { return rest_of_handle_split_before_sched2 (); }

}; // class pass_split_before_sched2

} // anon namespace

rtl_opt_pass *
make_pass_split_before_sched2 (gcc::context *ctxt)
{
  return new pass_split_before_sched2 (ctxt);
}

/* The placement of the splitting that we do for shorten_branches
   depends on whether regstack is used by the target or not.  */
static bool
gate_do_final_split (void)
{
#if HAVE_ATTR_length && !defined (STACK_REGS)
  return 1;
#else
  return 0;
#endif
}

namespace {

const pass_data pass_data_split_for_shorten_branches =
{
  RTL_PASS, /* type */
  "split5", /* name */
  OPTGROUP_NONE, /* optinfo_flags */
  true, /* has_gate */
  true, /* has_execute */
  TV_NONE, /* tv_id */
  0, /* properties_required */
  0, /* properties_provided */
  0, /* properties_destroyed */
  0, /* todo_flags_start */
  TODO_verify_rtl_sharing, /* todo_flags_finish */
};

class pass_split_for_shorten_branches : public rtl_opt_pass
{
public:
  pass_split_for_shorten_branches (gcc::context *ctxt)
    : rtl_opt_pass (pass_data_split_for_shorten_branches, ctxt)
  {}

  /* opt_pass methods: */
  bool gate () { return gate_do_final_split (); }
  unsigned int execute () { return split_all_insns_noflow (); }

}; // class pass_split_for_shorten_branches

} // anon namespace

rtl_opt_pass *
make_pass_split_for_shorten_branches (gcc::context *ctxt)
{
  return new pass_split_for_shorten_branches (ctxt);
}