c-family/

[official-gcc.git] / gcc / lra-constraints.c

/* Code for RTL transformations to satisfy insn constraints.
   Copyright (C) 2010, 2011, 2012
   Free Software Foundation, Inc.
   Contributed by Vladimir Makarov <vmakarov@redhat.com>.

   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/>.  */


/* This file contains code for 3 passes: constraint pass,
   inheritance/split pass, and pass for undoing failed inheritance and
   split.

   The major goal of constraint pass is to transform RTL to satisfy
   insn and address constraints by:
     o choosing insn alternatives;
     o generating *reload insns* (or reloads in brief) and *reload
       pseudos* which will get necessary hard registers later;
     o substituting pseudos with equivalent values and removing the
       instructions that initialized those pseudos.

   The constraint pass has biggest and most complicated code in LRA.
   There are a lot of important details like:
     o reuse of input reload pseudos to simplify reload pseudo
       allocations;
     o some heuristics to choose insn alternative to improve the
       inheritance;
     o early clobbers etc.

   The pass is mimicking former reload pass in alternative choosing
   because the reload pass is oriented to current machine description
   model.  It might be changed if the machine description model is
   changed.

   There is special code for preventing all LRA and this pass cycling
   in case of bugs.

   On the first iteration of the pass we process every instruction and
   choose an alternative for each one.  On subsequent iterations we try
   to avoid reprocessing instructions if we can be sure that the old
   choice is still valid.

   The inheritance/spilt pass is to transform code to achieve
   ineheritance and live range splitting.  It is done on backward
   traversal of EBBs.

   The inheritance optimization goal is to reuse values in hard
   registers. There is analogous optimization in old reload pass.  The
   inheritance is achieved by following transformation:

       reload_p1 <- p        reload_p1 <- p
       ...                   new_p <- reload_p1
       ...              =>   ...
       reload_p2 <- p        reload_p2 <- new_p

   where p is spilled and not changed between the insns.  Reload_p1 is
   also called *original pseudo* and new_p is called *inheritance
   pseudo*.

   The subsequent assignment pass will try to assign the same (or
   another if it is not possible) hard register to new_p as to
   reload_p1 or reload_p2.

   If the assignment pass fails to assign a hard register to new_p,
   this file will undo the inheritance and restore the original code.
   This is because implementing the above sequence with a spilled
   new_p would make the code much worse.  The inheritance is done in
   EBB scope.  The above is just a simplified example to get an idea
   of the inheritance as the inheritance is also done for non-reload
   insns.

   Splitting (transformation) is also done in EBB scope on the same
   pass as the inheritance:

       r <- ... or ... <- r              r <- ... or ... <- r
       ...                               s <- r (new insn -- save)
       ...                        => 
       ...                               r <- s (new insn -- restore)
       ... <- r                          ... <- r

    The *split pseudo* s is assigned to the hard register of the
    original pseudo or hard register r.

    Splitting is done:
      o In EBBs with high register pressure for global pseudos (living
        in at least 2 BBs) and assigned to hard registers when there
        are more one reloads needing the hard registers;
      o for pseudos needing save/restore code around calls.

    If the split pseudo still has the same hard register as the
    original pseudo after the subsequent assignment pass or the
    original pseudo was split, the opposite transformation is done on
    the same pass for undoing inheritance.  */

#undef REG_OK_STRICT

#include "config.h"
#include "system.h"
#include "coretypes.h"
#include "tm.h"
#include "hard-reg-set.h"
#include "rtl.h"
#include "tm_p.h"
#include "regs.h"
#include "insn-config.h"
#include "insn-codes.h"
#include "recog.h"
#include "output.h"
#include "addresses.h"
#include "target.h"
#include "function.h"
#include "expr.h"
#include "basic-block.h"
#include "except.h"
#include "optabs.h"
#include "df.h"
#include "ira.h"
#include "rtl-error.h"
#include "lra-int.h"

/* Value of LRA_CURR_RELOAD_NUM at the beginning of BB of the current
   insn.  Remember that LRA_CURR_RELOAD_NUM is the number of emitted
   reload insns.  */
static int bb_reload_num;

/* The current insn being processed and corresponding its data (basic
   block, the insn data, the insn static data, and the mode of each
   operand).  */
static rtx curr_insn;
static basic_block curr_bb;
static lra_insn_recog_data_t curr_id;
static struct lra_static_insn_data *curr_static_id;
static enum machine_mode curr_operand_mode[MAX_RECOG_OPERANDS];

\f

/* Start numbers for new registers and insns at the current constraints
   pass start.  */
static int new_regno_start;
static int new_insn_uid_start;

/* Return hard regno of REGNO or if it is was not assigned to a hard
   register, use a hard register from its allocno class.  */
static int
get_try_hard_regno (int regno)
{
  int hard_regno;
  enum reg_class rclass;

  if ((hard_regno = regno) >= FIRST_PSEUDO_REGISTER)
    hard_regno = lra_get_regno_hard_regno (regno);
  if (hard_regno >= 0)
    return hard_regno;
  rclass = lra_get_allocno_class (regno);
  if (rclass == NO_REGS)
    return -1;
  return ira_class_hard_regs[rclass][0];
}

/* Return final hard regno (plus offset) which will be after
   elimination.  We do this for matching constraints because the final
   hard regno could have a different class.  */
static int
get_final_hard_regno (int hard_regno, int offset)
{
  if (hard_regno < 0)
    return hard_regno;
  hard_regno = lra_get_elimination_hard_regno (hard_regno);
  return hard_regno + offset;
}

/* Return hard regno of X after removing subreg and making
   elimination.  If X is not a register or subreg of register, return
   -1.  For pseudo use its assignment.  */
static int
get_hard_regno (rtx x)
{
  rtx reg;
  int offset, hard_regno;

  reg = x;
  if (GET_CODE (x) == SUBREG)
    reg = SUBREG_REG (x);
  if (! REG_P (reg))
    return -1;
  if ((hard_regno = REGNO (reg)) >= FIRST_PSEUDO_REGISTER)
    hard_regno = lra_get_regno_hard_regno (hard_regno);
  if (hard_regno < 0)
    return -1;
  offset = 0;
  if (GET_CODE (x) == SUBREG)
    offset += subreg_regno_offset (hard_regno, GET_MODE (reg),
                                   SUBREG_BYTE (x),  GET_MODE (x));
  return get_final_hard_regno (hard_regno, offset);
}

/* If REGNO is a hard register or has been allocated a hard register,
   return the class of that register.  If REGNO is a reload pseudo
   created by the current constraints pass, return its allocno class.
   Return NO_REGS otherwise.  */
static enum reg_class
get_reg_class (int regno)
{
  int hard_regno;

  if ((hard_regno = regno) >= FIRST_PSEUDO_REGISTER)
    hard_regno = lra_get_regno_hard_regno (regno);
  if (hard_regno >= 0)
    {
      hard_regno = get_final_hard_regno (hard_regno, 0);
      return REGNO_REG_CLASS (hard_regno);
    }
  if (regno >= new_regno_start)
    return lra_get_allocno_class (regno);
  return NO_REGS;
}

/* Return true if REG satisfies (or will satisfy) reg class constraint
   CL.  Use elimination first if REG is a hard register.  If REG is a
   reload pseudo created by this constraints pass, assume that it will
   be allocated a hard register from its allocno class, but allow that
   class to be narrowed to CL if it is currently a superset of CL.

   If NEW_CLASS is nonnull, set *NEW_CLASS to the new allocno class of
   REGNO (reg), or NO_REGS if no change in its class was needed.  */
static bool
in_class_p (rtx reg, enum reg_class cl, enum reg_class *new_class)
{
  enum reg_class rclass, common_class;
  enum machine_mode reg_mode;
  int class_size, hard_regno, nregs, i, j;
  int regno = REGNO (reg);
  
  if (new_class != NULL)
    *new_class = NO_REGS;
  if (regno < FIRST_PSEUDO_REGISTER)
    {
      rtx final_reg = reg;
      rtx *final_loc = &final_reg;
      
      lra_eliminate_reg_if_possible (final_loc);
      return TEST_HARD_REG_BIT (reg_class_contents[cl], REGNO (*final_loc));
    }
  reg_mode = GET_MODE (reg);
  rclass = get_reg_class (regno);
  if (regno < new_regno_start
      /* Do not allow the constraints for reload instructions to
         influence the classes of new pseudos.  These reloads are
         typically moves that have many alternatives, and restricting
         reload pseudos for one alternative may lead to situations
         where other reload pseudos are no longer allocatable.  */
      || INSN_UID (curr_insn) >= new_insn_uid_start)
    /* When we don't know what class will be used finally for reload
       pseudos, we use ALL_REGS.  */
    return ((regno >= new_regno_start && rclass == ALL_REGS)
            || (rclass != NO_REGS && ira_class_subset_p[rclass][cl]
                && ! hard_reg_set_subset_p (reg_class_contents[cl],
                                            lra_no_alloc_regs)));
  else
    {
      common_class = ira_reg_class_subset[rclass][cl];
      if (new_class != NULL)
        *new_class = common_class;
      if (hard_reg_set_subset_p (reg_class_contents[common_class],
                                 lra_no_alloc_regs))
        return false;
      /* Check that there are enough allocatable regs.  */
      class_size = ira_class_hard_regs_num[common_class];
      for (i = 0; i < class_size; i++)
        {
          hard_regno = ira_class_hard_regs[common_class][i];
          nregs = hard_regno_nregs[hard_regno][reg_mode];
          if (nregs == 1)
            return true;
          for (j = 0; j < nregs; j++)
            if (TEST_HARD_REG_BIT (lra_no_alloc_regs, hard_regno + j))
              break;
          if (j >= nregs)
            return true;
        }
      return false;
    }
}

/* Return true if REGNO satisfies a memory constraint.  */
static bool
in_mem_p (int regno)
{
  return get_reg_class (regno) == NO_REGS;
}

/* If we have decided to substitute X with another value, return that
   value, otherwise return X.  */
static rtx
get_equiv_substitution (rtx x)
{
  int regno;
  rtx res;

  if (! REG_P (x) || (regno = REGNO (x)) < FIRST_PSEUDO_REGISTER
      || ! ira_reg_equiv[regno].defined_p
      || ! ira_reg_equiv[regno].profitable_p
      || lra_get_regno_hard_regno (regno) >= 0)
    return x;
  if ((res = ira_reg_equiv[regno].memory) != NULL_RTX)
    return res;
  if ((res = ira_reg_equiv[regno].constant) != NULL_RTX)
    return res;
  if ((res = ira_reg_equiv[regno].invariant) != NULL_RTX)
    return res;
  gcc_unreachable ();
}

/* Set up curr_operand_mode.  */
static void
init_curr_operand_mode (void)
{
  int nop = curr_static_id->n_operands;
  for (int i = 0; i < nop; i++)
    {
      enum machine_mode mode = GET_MODE (*curr_id->operand_loc[i]);
      if (mode == VOIDmode)
        {
          /* The .md mode for address operands is the mode of the
             addressed value rather than the mode of the address itself.  */
          if (curr_id->icode >= 0 && curr_static_id->operand[i].is_address)
            mode = Pmode;
          else
            mode = curr_static_id->operand[i].mode;
        }
      curr_operand_mode[i] = mode;
    }
}

\f

/* The page contains code to reuse input reloads.  */

/* Structure describes input reload of the current insns.  */
struct input_reload
{
  /* Reloaded value.  */
  rtx input;
  /* Reload pseudo used.  */
  rtx reg;
};

/* The number of elements in the following array.  */
static int curr_insn_input_reloads_num;
/* Array containing info about input reloads.  It is used to find the
   same input reload and reuse the reload pseudo in this case.  */
static struct input_reload curr_insn_input_reloads[LRA_MAX_INSN_RELOADS];

/* Initiate data concerning reuse of input reloads for the current
   insn.  */
static void
init_curr_insn_input_reloads (void)
{
  curr_insn_input_reloads_num = 0;
}

/* Change class of pseudo REGNO to NEW_CLASS.  Print info about it
   using TITLE.  Output a new line if NL_P.  */
static void
change_class (int regno, enum reg_class new_class,
              const char *title, bool nl_p)
{
  lra_assert (regno >= FIRST_PSEUDO_REGISTER);
  if (lra_dump_file != NULL)
    fprintf (lra_dump_file, "%s to class %s for r%d",
             title, reg_class_names[new_class], regno);
  setup_reg_classes (regno, new_class, NO_REGS, new_class);
  if (lra_dump_file != NULL && nl_p)
    fprintf (lra_dump_file, "\n");
}

/* Create a new pseudo using MODE, RCLASS, ORIGINAL or reuse already
   created input reload pseudo (only if TYPE is not OP_OUT).  The
   result pseudo is returned through RESULT_REG.  Return TRUE if we
   created a new pseudo, FALSE if we reused the already created input
   reload pseudo.  Use TITLE to describe new registers for debug
   purposes.  */
static bool
get_reload_reg (enum op_type type, enum machine_mode mode, rtx original,
                enum reg_class rclass, const char *title, rtx *result_reg)
{
  int i, regno;
  enum reg_class new_class;

  if (type == OP_OUT)
    {
      *result_reg
        = lra_create_new_reg_with_unique_value (mode, original, rclass, title);
      return true;
    }
  for (i = 0; i < curr_insn_input_reloads_num; i++)
    if (rtx_equal_p (curr_insn_input_reloads[i].input, original)
        && in_class_p (curr_insn_input_reloads[i].reg, rclass, &new_class))
      {
        lra_assert (! side_effects_p (original));
        *result_reg = curr_insn_input_reloads[i].reg;
        regno = REGNO (*result_reg);
        if (lra_dump_file != NULL)
          {
            fprintf (lra_dump_file, "    Reuse r%d for reload ", regno);
            print_value_slim (lra_dump_file, original, 1);
          }
        if (rclass != new_class)
          change_class (regno, new_class, ", change", false);
        if (lra_dump_file != NULL)
          fprintf (lra_dump_file, "\n");
        return false;
      }
  *result_reg = lra_create_new_reg (mode, original, rclass, title);
  lra_assert (curr_insn_input_reloads_num < LRA_MAX_INSN_RELOADS);
  curr_insn_input_reloads[curr_insn_input_reloads_num].input = original;
  curr_insn_input_reloads[curr_insn_input_reloads_num++].reg = *result_reg;
  return true;
}

\f

/* The page contains code to extract memory address parts.  */

/* Info about base and index regs of an address.  In some rare cases,
   base/index register can be actually memory.  In this case we will
   reload it.  */
struct address
{
  /* NULL if there is no a base register.  */
  rtx *base_reg_loc;
  /* Second location of {post/pre}_modify, NULL otherwise.  */
  rtx *base_reg_loc2;
  /* NULL if there is no an index register.  */
  rtx *index_reg_loc;
  /* Location of index reg * scale or index_reg_loc otherwise.  */
  rtx *index_loc;
  /* NULL if there is no a displacement.  */
  rtx *disp_loc;
  /* Defined if base_reg_loc is not NULL.  */
  enum rtx_code base_outer_code, index_code;
  /* True if the base register is modified in the address, for
     example, in PRE_INC.  */
  bool base_modify_p;
};

/* Wrapper around REGNO_OK_FOR_INDEX_P, to allow pseudos.  */
static inline bool
ok_for_index_p_nonstrict (rtx reg)
{
  unsigned regno = REGNO (reg);
  
  return regno >= FIRST_PSEUDO_REGISTER || REGNO_OK_FOR_INDEX_P (regno);
}

/* A version of regno_ok_for_base_p for use here, when all pseudos
   should count as OK.  Arguments as for regno_ok_for_base_p.  */
static inline bool
ok_for_base_p_nonstrict (rtx reg, enum machine_mode mode, addr_space_t as,
                         enum rtx_code outer_code, enum rtx_code index_code)
{
  unsigned regno = REGNO (reg);

  if (regno >= FIRST_PSEUDO_REGISTER)
    return true;
  return ok_for_base_p_1 (regno, mode, as, outer_code, index_code);
}

/* Process address part in space AS (or all address if TOP_P) with
   location *LOC to extract address characteristics.

   If CONTEXT_P is false, we are looking at the base part of an
   address, otherwise we are looking at the index part.

   MODE is the mode of the memory reference; OUTER_CODE and INDEX_CODE
   give the context that the rtx appears in; MODIFY_P if *LOC is
   modified.  */
static void
extract_loc_address_regs (bool top_p, enum machine_mode mode, addr_space_t as,
                          rtx *loc, bool context_p, enum rtx_code outer_code,
                          enum rtx_code index_code,
                          bool modify_p, struct address *ad)
{
  rtx x = *loc;
  enum rtx_code code = GET_CODE (x);
  bool base_ok_p;

  switch (code)
    {
    case CONST_INT:
    case CONST:
    case SYMBOL_REF:
    case LABEL_REF:
      if (! context_p)
        {
          lra_assert (top_p);
          ad->disp_loc = loc;
        }
      return;

    case CC0:
    case PC:
      return;

    case ZERO_EXTEND:
      /* Pass TOP_P for displacement.  */
      extract_loc_address_regs (top_p, mode, as, &XEXP (*loc, 0), context_p,
                                code, index_code, modify_p, ad);
      return;

    case PLUS:
    case LO_SUM:
      /* When we have an address that is a sum, we must determine
         whether registers are "base" or "index" regs.  If there is a
         sum of two registers, we must choose one to be the
         "base".  */
      {
        rtx *arg0_loc = &XEXP (x, 0);
        rtx *arg1_loc = &XEXP (x, 1);
        rtx *tloc;
        rtx arg0 = *arg0_loc;
        rtx arg1 = *arg1_loc;
        enum rtx_code code0 = GET_CODE (arg0);
        enum rtx_code code1 = GET_CODE (arg1);

        /* Look inside subregs.  */
        if (code0 == SUBREG)
          {
            arg0_loc = &SUBREG_REG (arg0);
            arg0 = *arg0_loc;
            code0 = GET_CODE (arg0);
          }
        if (code1 == SUBREG)
          {
            arg1_loc = &SUBREG_REG (arg1);
            arg1 = *arg1_loc;
            code1 = GET_CODE (arg1);
          }

        if (CONSTANT_P (arg0)
            || code1 == PLUS || code1 == MULT || code1 == ASHIFT)
          {
            tloc = arg1_loc;
            arg1_loc = arg0_loc;
            arg0_loc = tloc;
            arg0 = *arg0_loc;
            code0 = GET_CODE (arg0);
            arg1 = *arg1_loc;
            code1 = GET_CODE (arg1);
          }
        /* If this machine only allows one register per address, it
           must be in the first operand.  */
        if (MAX_REGS_PER_ADDRESS == 1 || code == LO_SUM)
          {
            lra_assert (ad->disp_loc == NULL);
            ad->disp_loc = arg1_loc;
            extract_loc_address_regs (false, mode, as, arg0_loc, false, code,
                                      code1, modify_p, ad);
          }
        /* Base + disp addressing  */
        else if (code0 != PLUS && code0 != MULT && code0 != ASHIFT
                 && CONSTANT_P (arg1))
          {
            lra_assert (ad->disp_loc == NULL);
            ad->disp_loc = arg1_loc;
            extract_loc_address_regs (false, mode, as, arg0_loc, false, PLUS,
                                      code1, modify_p, ad);
          }
        /* If index and base registers are the same on this machine,
           just record registers in any non-constant operands.  We
           assume here, as well as in the tests below, that all
           addresses are in canonical form.  */
        else if (INDEX_REG_CLASS
                 == base_reg_class (VOIDmode, as, PLUS, SCRATCH)
                 && code0 != PLUS && code0 != MULT && code0 != ASHIFT)
          {
            extract_loc_address_regs (false, mode, as, arg0_loc, false, PLUS,
                                      code1, modify_p, ad);
            lra_assert (! CONSTANT_P (arg1));
            extract_loc_address_regs (false, mode, as, arg1_loc, true, PLUS,
                                      code0, modify_p, ad);
          }
        /* It might be [base + ]index * scale + disp. */
        else if (CONSTANT_P (arg1))
          {
            lra_assert (ad->disp_loc == NULL);
            ad->disp_loc = arg1_loc;
            extract_loc_address_regs (false, mode, as, arg0_loc, context_p,
                                      PLUS, code0, modify_p, ad);
          }
        /* If both operands are registers but one is already a hard
           register of index or reg-base class, give the other the
           class that the hard register is not.  */
        else if (code0 == REG && code1 == REG
                 && REGNO (arg0) < FIRST_PSEUDO_REGISTER
                 && ((base_ok_p
                      = ok_for_base_p_nonstrict (arg0, mode, as, PLUS, REG))
                     || ok_for_index_p_nonstrict (arg0)))
          {
            extract_loc_address_regs (false, mode, as, arg0_loc, ! base_ok_p,
                                      PLUS, REG, modify_p, ad);
            extract_loc_address_regs (false, mode, as, arg1_loc, base_ok_p,
                                      PLUS, REG, modify_p, ad);
          }
        else if (code0 == REG && code1 == REG
                 && REGNO (arg1) < FIRST_PSEUDO_REGISTER
                 && ((base_ok_p
                      = ok_for_base_p_nonstrict (arg1, mode, as, PLUS, REG))
                     || ok_for_index_p_nonstrict (arg1)))
          {
            extract_loc_address_regs (false, mode, as, arg0_loc, base_ok_p,
                                      PLUS, REG, modify_p, ad);
            extract_loc_address_regs (false, mode, as, arg1_loc, ! base_ok_p,
                                      PLUS, REG, modify_p, ad);
          }
        /* Otherwise, count equal chances that each might be a base or
           index register.  This case should be rare.  */
        else
          {
            extract_loc_address_regs (false, mode, as, arg0_loc, false, PLUS,
                                      code1, modify_p, ad);
            extract_loc_address_regs (false, mode, as, arg1_loc,
                                      ad->base_reg_loc != NULL, PLUS,
                                      code0, modify_p, ad);
          }
      }
      break;

    case MULT:
    case ASHIFT:
      {
        rtx *arg0_loc = &XEXP (x, 0);
        enum rtx_code code0 = GET_CODE (*arg0_loc);
        
        if (code0 == CONST_INT)
          arg0_loc = &XEXP (x, 1);
        extract_loc_address_regs (false, mode, as, arg0_loc, true,
                                  outer_code, code, modify_p, ad);
        lra_assert (ad->index_loc == NULL);
        ad->index_loc = loc;
        break;
      }

    case POST_MODIFY:
    case PRE_MODIFY:
      extract_loc_address_regs (false, mode, as, &XEXP (x, 0), false,
                                code, GET_CODE (XEXP (XEXP (x, 1), 1)),
                                true, ad);
      lra_assert (rtx_equal_p (XEXP (XEXP (x, 1), 0), XEXP (x, 0)));
      ad->base_reg_loc2 = &XEXP (XEXP (x, 1), 0);
      if (REG_P (XEXP (XEXP (x, 1), 1)))
        extract_loc_address_regs (false, mode, as, &XEXP (XEXP (x, 1), 1),
                                  true, code, REG, modify_p, ad);
      break;

    case POST_INC:
    case PRE_INC:
    case POST_DEC:
    case PRE_DEC:
      extract_loc_address_regs (false, mode, as, &XEXP (x, 0), false, code,
                                SCRATCH, true, ad);
      break;

      /* We process memory as a register.  That means we flatten
         addresses.  In other words, the final code will never
         contains memory in an address even if the target supports
         such addresses (it is too rare these days).  Memory also can
         occur in address as a result some previous transformations
         like equivalence substitution.  */
    case MEM:
    case REG:
      if (context_p)
        {
          lra_assert (ad->index_reg_loc == NULL);
          ad->index_reg_loc = loc;
        }
      else
        {
          lra_assert (ad->base_reg_loc == NULL);
          ad->base_reg_loc = loc;
          ad->base_outer_code = outer_code;
          ad->index_code = index_code;
          ad->base_modify_p = modify_p;
        }
      break;
    default:
      {
        const char *fmt = GET_RTX_FORMAT (code);
        int i;

        if (GET_RTX_LENGTH (code) != 1
            || fmt[0] != 'e' || GET_CODE (XEXP (x, 0)) != UNSPEC)
          {
            for (i = GET_RTX_LENGTH (code) - 1; i >= 0; i--)
              if (fmt[i] == 'e')
                extract_loc_address_regs (false, mode, as, &XEXP (x, i),
                                          context_p, code, SCRATCH,
                                          modify_p, ad);
            break;
          }
        /* fall through for case UNARY_OP (UNSPEC ...)  */
      }

    case UNSPEC:
      if (ad->disp_loc == NULL)
        ad->disp_loc = loc;
      else if (ad->base_reg_loc == NULL)
        {
          ad->base_reg_loc = loc;
          ad->base_outer_code = outer_code;
          ad->index_code = index_code;
          ad->base_modify_p = modify_p;
        }
      else
        {
          lra_assert (ad->index_reg_loc == NULL);
          ad->index_reg_loc = loc;
        }
      break;

    }
}


/* Describe address *LOC in AD.  There are two cases:
   - *LOC is the address in a (mem ...).  In this case OUTER_CODE is MEM
     and AS is the mem's address space.
   - *LOC is matched to an address constraint such as 'p'.  In this case
     OUTER_CODE is ADDRESS and AS is ADDR_SPACE_GENERIC.  */
static void
extract_address_regs (enum machine_mode mem_mode, addr_space_t as,
                      rtx *loc, enum rtx_code outer_code, struct address *ad)
{
  ad->base_reg_loc = ad->base_reg_loc2
    = ad->index_reg_loc = ad->index_loc = ad->disp_loc = NULL;
  ad->base_outer_code = SCRATCH;
  ad->index_code = SCRATCH;
  ad->base_modify_p = false;
  extract_loc_address_regs (true, mem_mode, as, loc, false, outer_code,
                            SCRATCH, false, ad);  
  if (ad->index_loc == NULL)
    /* SUBREG ??? */
    ad->index_loc = ad->index_reg_loc;
}

\f

/* The page contains major code to choose the current insn alternative
   and generate reloads for it.  */

/* Return the offset from REGNO of the least significant register
   in (reg:MODE REGNO).

   This function is used to tell whether two registers satisfy
   a matching constraint.  (reg:MODE1 REGNO1) matches (reg:MODE2 REGNO2) if:

         REGNO1 + lra_constraint_offset (REGNO1, MODE1)
         == REGNO2 + lra_constraint_offset (REGNO2, MODE2)  */
int
lra_constraint_offset (int regno, enum machine_mode mode)
{
  lra_assert (regno < FIRST_PSEUDO_REGISTER);
  if (WORDS_BIG_ENDIAN && GET_MODE_SIZE (mode) > UNITS_PER_WORD
      && SCALAR_INT_MODE_P (mode))
    return hard_regno_nregs[regno][mode] - 1;
  return 0;
}

/* Like rtx_equal_p except that it allows a REG and a SUBREG to match
   if they are the same hard reg, and has special hacks for
   auto-increment and auto-decrement.  This is specifically intended for
   process_alt_operands to use in determining whether two operands
   match.  X is the operand whose number is the lower of the two.

   It is supposed that X is the output operand and Y is the input
   operand.  Y_HARD_REGNO is the final hard regno of register Y or
   register in subreg Y as we know it now.  Otherwise, it is a
   negative value.  */
static bool
operands_match_p (rtx x, rtx y, int y_hard_regno)
{
  int i;
  RTX_CODE code = GET_CODE (x);
  const char *fmt;

  if (x == y)
    return true;
  if ((code == REG || (code == SUBREG && REG_P (SUBREG_REG (x))))
      && (REG_P (y) || (GET_CODE (y) == SUBREG && REG_P (SUBREG_REG (y)))))
    {
      int j;
      
      i = get_hard_regno (x);
      if (i < 0)
        goto slow;

      if ((j = y_hard_regno) < 0)
        goto slow;

      i += lra_constraint_offset (i, GET_MODE (x));
      j += lra_constraint_offset (j, GET_MODE (y));

      return i == j;
    }

  /* If two operands must match, because they are really a single
     operand of an assembler insn, then two post-increments are invalid
     because the assembler insn would increment only once.  On the
     other hand, a post-increment matches ordinary indexing if the
     post-increment is the output operand.  */
  if (code == POST_DEC || code == POST_INC || code == POST_MODIFY)
    return operands_match_p (XEXP (x, 0), y, y_hard_regno);

  /* Two pre-increments are invalid because the assembler insn would
     increment only once.  On the other hand, a pre-increment matches
     ordinary indexing if the pre-increment is the input operand.  */
  if (GET_CODE (y) == PRE_DEC || GET_CODE (y) == PRE_INC
      || GET_CODE (y) == PRE_MODIFY)
    return operands_match_p (x, XEXP (y, 0), -1);
  
 slow:

  if (code == REG && GET_CODE (y) == SUBREG && REG_P (SUBREG_REG (y))
      && x == SUBREG_REG (y))
    return true;
  if (GET_CODE (y) == REG && code == SUBREG && REG_P (SUBREG_REG (x))
      && SUBREG_REG (x) == y)
    return true;

  /* Now we have disposed of all the cases in which different rtx
     codes can match.  */
  if (code != GET_CODE (y))
    return false;

  /* (MULT:SI x y) and (MULT:HI x y) are NOT equivalent.  */
  if (GET_MODE (x) != GET_MODE (y))
    return false;

  switch (code)
    {
    CASE_CONST_UNIQUE:
      return false;

    case LABEL_REF:
      return XEXP (x, 0) == XEXP (y, 0);
    case SYMBOL_REF:
      return XSTR (x, 0) == XSTR (y, 0);

    default:
      break;
    }

  /* Compare the elements.  If any pair of corresponding elements fail
     to match, return false for the whole things.  */

  fmt = GET_RTX_FORMAT (code);
  for (i = GET_RTX_LENGTH (code) - 1; i >= 0; i--)
    {
      int val, j;
      switch (fmt[i])
        {
        case 'w':
          if (XWINT (x, i) != XWINT (y, i))
            return false;
          break;

        case 'i':
          if (XINT (x, i) != XINT (y, i))
            return false;
          break;

        case 'e':
          val = operands_match_p (XEXP (x, i), XEXP (y, i), -1);
          if (val == 0)
            return false;
          break;

        case '0':
          break;

        case 'E':
          if (XVECLEN (x, i) != XVECLEN (y, i))
            return false;
          for (j = XVECLEN (x, i) - 1; j >= 0; --j)
            {
              val = operands_match_p (XVECEXP (x, i, j), XVECEXP (y, i, j), -1);
              if (val == 0)
                return false;
            }
          break;

          /* It is believed that rtx's at this level will never
             contain anything but integers and other rtx's, except for
             within LABEL_REFs and SYMBOL_REFs.  */
        default:
          gcc_unreachable ();
        }
    }
  return true;
}

/* True if X is a constant that can be forced into the constant pool.
   MODE is the mode of the operand, or VOIDmode if not known.  */
#define CONST_POOL_OK_P(MODE, X)                \
  ((MODE) != VOIDmode                           \
   && CONSTANT_P (X)                            \
   && GET_CODE (X) != HIGH                      \
   && !targetm.cannot_force_const_mem (MODE, X))

/* True if C is a non-empty register class that has too few registers
   to be safely used as a reload target class.  */
#define SMALL_REGISTER_CLASS_P(C)                                       \
  (reg_class_size [(C)] == 1                                            \
   || (reg_class_size [(C)] >= 1 && targetm.class_likely_spilled_p (C)))

/* If REG is a reload pseudo, try to make its class satisfying CL.  */
static void
narrow_reload_pseudo_class (rtx reg, enum reg_class cl)
{
  enum reg_class rclass;

  /* Do not make more accurate class from reloads generated.  They are
     mostly moves with a lot of constraints.  Making more accurate
     class may results in very narrow class and impossibility of find
     registers for several reloads of one insn.  */
  if (INSN_UID (curr_insn) >= new_insn_uid_start)
    return;
  if (GET_CODE (reg) == SUBREG)
    reg = SUBREG_REG (reg);
  if (! REG_P (reg) || (int) REGNO (reg) < new_regno_start)
    return;
  if (in_class_p (reg, cl, &rclass) && rclass != cl)
    change_class (REGNO (reg), rclass, "      Change", true);
}

/* Generate reloads for matching OUT and INS (array of input operand
   numbers with end marker -1) with reg class GOAL_CLASS.  Add input
   and output reloads correspondingly to the lists *BEFORE and
   *AFTER.  */
static void
match_reload (signed char out, signed char *ins, enum reg_class goal_class,
              rtx *before, rtx *after)
{
  int i, in;
  rtx new_in_reg, new_out_reg, reg;
  enum machine_mode inmode, outmode;
  rtx in_rtx = *curr_id->operand_loc[ins[0]];
  rtx out_rtx = *curr_id->operand_loc[out];

  outmode = curr_operand_mode[out];
  inmode = curr_operand_mode[ins[0]];
  push_to_sequence (*before);
  if (inmode != outmode)
    {
      if (GET_MODE_SIZE (inmode) > GET_MODE_SIZE (outmode))
        {
          reg = new_in_reg
            = lra_create_new_reg_with_unique_value (inmode, in_rtx,
                                                    goal_class, "");
          if (SCALAR_INT_MODE_P (inmode))
            new_out_reg = gen_lowpart_SUBREG (outmode, reg);
          else
            new_out_reg = gen_rtx_SUBREG (outmode, reg, 0);
        }
      else
        {
          reg = new_out_reg
            = lra_create_new_reg_with_unique_value (outmode, out_rtx,
                                                    goal_class, "");
          if (SCALAR_INT_MODE_P (outmode))
            new_in_reg = gen_lowpart_SUBREG (inmode, reg);
          else
            new_in_reg = gen_rtx_SUBREG (inmode, reg, 0);
          /* NEW_IN_REG is non-paradoxical subreg.  We don't want
             NEW_OUT_REG living above.  We add clobber clause for
             this.  */
          emit_clobber (new_out_reg);
        }
    }
  else
    {
      /* Pseudos have values -- see comments for lra_reg_info.
         Different pseudos with the same value do not conflict even if
         they live in the same place.  When we create a pseudo we
         assign value of original pseudo (if any) from which we
         created the new pseudo.  If we create the pseudo from the
         input pseudo, the new pseudo will no conflict with the input
         pseudo which is wrong when the input pseudo lives after the
         insn and as the new pseudo value is changed by the insn
         output.  Therefore we create the new pseudo from the output.
         
         We cannot reuse the current output register because we might
         have a situation like "a <- a op b", where the constraints
         force the second input operand ("b") to match the output
         operand ("a").  "b" must then be copied into a new register
         so that it doesn't clobber the current value of "a".  */
         
      new_in_reg = new_out_reg
        = lra_create_new_reg_with_unique_value (outmode, out_rtx,
                                                goal_class, "");
    }
  /* In and out operand can be got from transformations before
     processing insn constraints.  One example of such transformations
     is subreg reloading (see function simplify_operand_subreg).  The
     new pseudos created by the transformations might have inaccurate
     class (ALL_REGS) and we should make their classes more
     accurate.  */
  narrow_reload_pseudo_class (in_rtx, goal_class);
  narrow_reload_pseudo_class (out_rtx, goal_class);
  lra_emit_move (copy_rtx (new_in_reg), in_rtx);
  *before = get_insns ();
  end_sequence ();
  for (i = 0; (in = ins[i]) >= 0; i++)
    {
      lra_assert
        (GET_MODE (*curr_id->operand_loc[in]) == VOIDmode
         || GET_MODE (new_in_reg) == GET_MODE (*curr_id->operand_loc[in]));
      *curr_id->operand_loc[in] = new_in_reg;
    }
  lra_update_dups (curr_id, ins);
  if (find_reg_note (curr_insn, REG_UNUSED, out_rtx) == NULL_RTX)
    {
      start_sequence ();
      lra_emit_move (out_rtx, copy_rtx (new_out_reg));
      emit_insn (*after);
      *after = get_insns ();
      end_sequence ();
    }
  *curr_id->operand_loc[out] = new_out_reg;
  lra_update_dup (curr_id, out);
}

/* Return register class which is union of all reg classes in insn
   constraint alternative string starting with P.  */
static enum reg_class
reg_class_from_constraints (const char *p)
{
  int c, len;
  enum reg_class op_class = NO_REGS;

  do
    switch ((c = *p, len = CONSTRAINT_LEN (c, p)), c)
      {
      case '#':
      case ',':
        return op_class;

      case 'p':
        op_class = (reg_class_subunion
                    [op_class][base_reg_class (VOIDmode, ADDR_SPACE_GENERIC,
                                               ADDRESS, SCRATCH)]);
        break;
        
      case 'g':
      case 'r':
        op_class = reg_class_subunion[op_class][GENERAL_REGS];
        break;
        
      default:
        if (REG_CLASS_FROM_CONSTRAINT (c, p) == NO_REGS)
          {
#ifdef EXTRA_CONSTRAINT_STR
            if (EXTRA_ADDRESS_CONSTRAINT (c, p))
              op_class
                = (reg_class_subunion
                   [op_class][base_reg_class (VOIDmode, ADDR_SPACE_GENERIC,
                                              ADDRESS, SCRATCH)]);
#endif
            break;
          }
        
        op_class
          = reg_class_subunion[op_class][REG_CLASS_FROM_CONSTRAINT (c, p)];
        break;
      }
  while ((p += len), c);
  return op_class;
}

/* If OP is a register, return the class of the register as per
   get_reg_class, otherwise return NO_REGS.  */
static inline enum reg_class
get_op_class (rtx op)
{
  return REG_P (op) ? get_reg_class (REGNO (op)) : NO_REGS;
}

/* Return generated insn mem_pseudo:=val if TO_P or val:=mem_pseudo
   otherwise.  If modes of MEM_PSEUDO and VAL are different, use
   SUBREG for VAL to make them equal.  */
static rtx
emit_spill_move (bool to_p, rtx mem_pseudo, rtx val)
{
  if (GET_MODE (mem_pseudo) != GET_MODE (val))
    val = gen_rtx_SUBREG (GET_MODE (mem_pseudo),
                          GET_CODE (val) == SUBREG ? SUBREG_REG (val) : val,
                          0);
  return (to_p
          ? gen_move_insn (mem_pseudo, val)
          : gen_move_insn (val, mem_pseudo));
}

/* Process a special case insn (register move), return true if we
   don't need to process it anymore.  Return that RTL was changed
   through CHANGE_P and macro SECONDARY_MEMORY_NEEDED says to use
   secondary memory through SEC_MEM_P.  */
static bool
check_and_process_move (bool *change_p, bool *sec_mem_p)
{
  int sregno, dregno;
  rtx set, dest, src, dreg, sreg, old_sreg, new_reg, before, scratch_reg;
  enum reg_class dclass, sclass, secondary_class;
  enum machine_mode sreg_mode;
  secondary_reload_info sri;

  *sec_mem_p = *change_p = false;
  if ((set = single_set (curr_insn)) == NULL)
    return false;
  dreg = dest = SET_DEST (set);
  sreg = src = SET_SRC (set);
  /* Quick check on the right move insn which does not need
     reloads.  */
  if ((dclass = get_op_class (dest)) != NO_REGS
      && (sclass = get_op_class (src)) != NO_REGS
      /* The backend guarantees that register moves of cost 2 never
         need reloads.  */
      && targetm.register_move_cost (GET_MODE (src), dclass, sclass) == 2)
    return true;
  if (GET_CODE (dest) == SUBREG)
    dreg = SUBREG_REG (dest);
  if (GET_CODE (src) == SUBREG)
    sreg = SUBREG_REG (src);
  if (! REG_P (dreg) || ! REG_P (sreg))
    return false;
  sclass = dclass = NO_REGS;
  dreg = get_equiv_substitution (dreg);
  if (REG_P (dreg))
    dclass = get_reg_class (REGNO (dreg));
  if (dclass == ALL_REGS)
    /* ALL_REGS is used for new pseudos created by transformations
       like reload of SUBREG_REG (see function
       simplify_operand_subreg).  We don't know their class yet.  We
       should figure out the class from processing the insn
       constraints not in this fast path function.  Even if ALL_REGS
       were a right class for the pseudo, secondary_... hooks usually
       are not define for ALL_REGS.  */
    return false;
  sreg_mode = GET_MODE (sreg);
  old_sreg = sreg;
  sreg = get_equiv_substitution (sreg);
  if (REG_P (sreg))
    sclass = get_reg_class (REGNO (sreg));
  if (sclass == ALL_REGS)
    /* See comments above.  */
    return false;
#ifdef SECONDARY_MEMORY_NEEDED
  if (dclass != NO_REGS && sclass != NO_REGS
      && SECONDARY_MEMORY_NEEDED (sclass, dclass, GET_MODE (src)))
    {
      *sec_mem_p = true;
      return false;
    }
#endif
  sri.prev_sri = NULL;
  sri.icode = CODE_FOR_nothing;
  sri.extra_cost = 0;
  secondary_class = NO_REGS;
  /* Set up hard register for a reload pseudo for hook
     secondary_reload because some targets just ignore unassigned
     pseudos in the hook.  */
  if (dclass != NO_REGS && lra_get_regno_hard_regno (REGNO (dreg)) < 0)
    {
      dregno = REGNO (dreg);
      reg_renumber[dregno] = ira_class_hard_regs[dclass][0];
    }
  else
    dregno = -1;
  if (sclass != NO_REGS && lra_get_regno_hard_regno (REGNO (sreg)) < 0)
    {
      sregno = REGNO (sreg);
      reg_renumber[sregno] = ira_class_hard_regs[sclass][0];
    }
  else
    sregno = -1;
  if (sclass != NO_REGS)
    secondary_class
      = (enum reg_class) targetm.secondary_reload (false, dest,
                                                   (reg_class_t) sclass,
                                                   GET_MODE (src), &sri);
  if (sclass == NO_REGS
      || ((secondary_class != NO_REGS || sri.icode != CODE_FOR_nothing)
          && dclass != NO_REGS))
    {
#if ENABLE_ASSERT_CHECKING
      enum reg_class old_sclass = secondary_class;
      secondary_reload_info old_sri = sri;
#endif

      sri.prev_sri = NULL;
      sri.icode = CODE_FOR_nothing;
      sri.extra_cost = 0;
      secondary_class
        = (enum reg_class) targetm.secondary_reload (true, sreg,
                                                     (reg_class_t) dclass,
                                                     sreg_mode, &sri);
      /* Check the target hook consistency.  */
      lra_assert
        ((secondary_class == NO_REGS && sri.icode == CODE_FOR_nothing)
         || (old_sclass == NO_REGS && old_sri.icode == CODE_FOR_nothing)
         || (secondary_class == old_sclass && sri.icode == old_sri.icode));
    }
  if (sregno >= 0)
    reg_renumber [sregno] = -1;
  if (dregno >= 0)
    reg_renumber [dregno] = -1;
  if (secondary_class == NO_REGS && sri.icode == CODE_FOR_nothing)
    return false;
  *change_p = true;
  new_reg = NULL_RTX;
  if (secondary_class != NO_REGS)
    new_reg = lra_create_new_reg_with_unique_value (sreg_mode, NULL_RTX,
                                                    secondary_class,
                                                    "secondary");
  start_sequence ();
  if (old_sreg != sreg)
    sreg = copy_rtx (sreg);
  if (sri.icode == CODE_FOR_nothing)
    lra_emit_move (new_reg, sreg);
  else
    {
      enum reg_class scratch_class;

      scratch_class = (reg_class_from_constraints
                       (insn_data[sri.icode].operand[2].constraint));
      scratch_reg = (lra_create_new_reg_with_unique_value
                     (insn_data[sri.icode].operand[2].mode, NULL_RTX,
                      scratch_class, "scratch"));
      emit_insn (GEN_FCN (sri.icode) (new_reg != NULL_RTX ? new_reg : dest,
                                      sreg, scratch_reg));
    }
  before = get_insns ();
  end_sequence ();
  lra_process_new_insns (curr_insn, before, NULL_RTX, "Inserting the move");
  if (new_reg != NULL_RTX)
    {
      if (GET_CODE (src) == SUBREG)
        SUBREG_REG (src) = new_reg;
      else
        SET_SRC (set) = new_reg;
    }
  else
    {
      if (lra_dump_file != NULL)
        {
          fprintf (lra_dump_file, "Deleting move %u\n", INSN_UID (curr_insn));
          debug_rtl_slim (lra_dump_file, curr_insn, curr_insn, -1, 0);
        }
      lra_set_insn_deleted (curr_insn);
      return true;
    }
  return false;
}

/* The following data describe the result of process_alt_operands.
   The data are used in curr_insn_transform to generate reloads.  */

/* The chosen reg classes which should be used for the corresponding
   operands.  */
static enum reg_class goal_alt[MAX_RECOG_OPERANDS];
/* True if the operand should be the same as another operand and that
   other operand does not need a reload.  */
static bool goal_alt_match_win[MAX_RECOG_OPERANDS];
/* True if the operand does not need a reload.  */
static bool goal_alt_win[MAX_RECOG_OPERANDS];
/* True if the operand can be offsetable memory.  */
static bool goal_alt_offmemok[MAX_RECOG_OPERANDS];
/* The number of an operand to which given operand can be matched to.  */
static int goal_alt_matches[MAX_RECOG_OPERANDS];
/* The number of elements in the following array.  */
static int goal_alt_dont_inherit_ops_num;
/* Numbers of operands whose reload pseudos should not be inherited.  */
static int goal_alt_dont_inherit_ops[MAX_RECOG_OPERANDS];
/* True if the insn commutative operands should be swapped.  */
static bool goal_alt_swapped;
/* The chosen insn alternative.  */
static int goal_alt_number;

/* The following five variables are used to choose the best insn
   alternative.  They reflect final characteristics of the best
   alternative.  */

/* Number of necessary reloads and overall cost reflecting the
   previous value and other unpleasantness of the best alternative.  */
static int best_losers, best_overall;
/* Number of small register classes used for operands of the best
   alternative.  */
static int best_small_class_operands_num;
/* Overall number hard registers used for reloads.  For example, on
   some targets we need 2 general registers to reload DFmode and only
   one floating point register.  */
static int best_reload_nregs;
/* Overall number reflecting distances of previous reloading the same
   value.  The distances are counted from the current BB start.  It is
   used to improve inheritance chances.  */
static int best_reload_sum;

/* True if the current insn should have no correspondingly input or
   output reloads.  */
static bool no_input_reloads_p, no_output_reloads_p;

/* True if we swapped the commutative operands in the current
   insn.  */
static int curr_swapped;

/* Arrange for address element *LOC to be a register of class CL.
   Add any input reloads to list BEFORE.  AFTER is nonnull if *LOC is an
   automodified value; handle that case by adding the required output
   reloads to list AFTER.  Return true if the RTL was changed.  */
static bool
process_addr_reg (rtx *loc, rtx *before, rtx *after, enum reg_class cl)
{
  int regno;
  enum reg_class rclass, new_class;
  rtx reg = *loc;
  rtx new_reg;
  enum machine_mode mode;
  bool before_p = false;

  mode = GET_MODE (reg);
  if (! REG_P (reg))
    {
      /* Always reload memory in an address even if the target supports
         such addresses.  */
      new_reg = lra_create_new_reg_with_unique_value (mode, reg, cl, "address");
      before_p = true;
    }
  else
    {
      regno = REGNO (reg);
      rclass = get_reg_class (regno);
      if ((*loc = get_equiv_substitution (reg)) != reg)
        {
          if (lra_dump_file != NULL)
            {
              fprintf (lra_dump_file,
                       "Changing pseudo %d in address of insn %u on equiv ",
                       REGNO (reg), INSN_UID (curr_insn));
              print_value_slim (lra_dump_file, *loc, 1);
              fprintf (lra_dump_file, "\n");
            }
          *loc = copy_rtx (*loc);
        }
      if (*loc != reg || ! in_class_p (reg, cl, &new_class))
        {
          reg = *loc;
          if (get_reload_reg (after == NULL ? OP_IN : OP_INOUT,
                              mode, reg, cl, "address", &new_reg))
            before_p = true;
        }
      else if (new_class != NO_REGS && rclass != new_class)
        {
          change_class (regno, new_class, "        Change", true);
          return false;
        }
      else
        return false;
    }
  if (before_p)
    {
      push_to_sequence (*before);
      lra_emit_move (new_reg, reg);
      *before = get_insns ();
      end_sequence ();
    }
  *loc = new_reg;
  if (after != NULL)
    {
      start_sequence ();
      lra_emit_move (reg, new_reg);
      emit_insn (*after);
      *after = get_insns ();
      end_sequence ();
    }
  return true;
}

#ifndef SLOW_UNALIGNED_ACCESS
#define SLOW_UNALIGNED_ACCESS(mode, align) 0
#endif

/* Make reloads for subreg in operand NOP with internal subreg mode
   REG_MODE, add new reloads for further processing.  Return true if
   any reload was generated.  */
static bool
simplify_operand_subreg (int nop, enum machine_mode reg_mode)
{
  int hard_regno;
  rtx before, after;
  enum machine_mode mode;
  rtx reg, new_reg;
  rtx operand = *curr_id->operand_loc[nop];

  before = after = NULL_RTX;

  if (GET_CODE (operand) != SUBREG)
    return false;
  
  mode = GET_MODE (operand);
  reg = SUBREG_REG (operand);
  /* If we change address for paradoxical subreg of memory, the
     address might violate the necessary alignment or the access might
     be slow.  So take this into consideration.  */
  if ((MEM_P (reg)
       && ((! STRICT_ALIGNMENT
            && ! SLOW_UNALIGNED_ACCESS (mode, MEM_ALIGN (reg)))
           || MEM_ALIGN (reg) >= GET_MODE_ALIGNMENT (mode)))
      || (REG_P (reg) && REGNO (reg) < FIRST_PSEUDO_REGISTER))
    {
      alter_subreg (curr_id->operand_loc[nop], false);
      return true;
    }
  /* Put constant into memory when we have mixed modes.  It generates
     a better code in most cases as it does not need a secondary
     reload memory.  It also prevents LRA looping when LRA is using
     secondary reload memory again and again.  */
  if (CONSTANT_P (reg) && CONST_POOL_OK_P (reg_mode, reg)
      && SCALAR_INT_MODE_P (reg_mode) != SCALAR_INT_MODE_P (mode))
    {
      SUBREG_REG (operand) = force_const_mem (reg_mode, reg);
      alter_subreg (curr_id->operand_loc[nop], false);
      return true;
    }
  /* Force a reload of the SUBREG_REG if this is a constant or PLUS or
     if there may be a problem accessing OPERAND in the outer
     mode.  */
  if ((REG_P (reg)
       && REGNO (reg) >= FIRST_PSEUDO_REGISTER
       && (hard_regno = lra_get_regno_hard_regno (REGNO (reg))) >= 0
       /* Don't reload paradoxical subregs because we could be looping
          having repeatedly final regno out of hard regs range.  */
       && (hard_regno_nregs[hard_regno][GET_MODE (reg)]
           >= hard_regno_nregs[hard_regno][mode])
       && simplify_subreg_regno (hard_regno, GET_MODE (reg),
                                 SUBREG_BYTE (operand), mode) < 0)
      || CONSTANT_P (reg) || GET_CODE (reg) == PLUS || MEM_P (reg))
    {
      enum op_type type = curr_static_id->operand[nop].type;
      /* The class will be defined later in curr_insn_transform.  */
      enum reg_class rclass
        = (enum reg_class) targetm.preferred_reload_class (reg, ALL_REGS);

      new_reg = lra_create_new_reg_with_unique_value (reg_mode, reg, rclass,
                                                      "subreg reg");
      bitmap_set_bit (&lra_optional_reload_pseudos, REGNO (new_reg));
      if (type != OP_OUT
          || GET_MODE_SIZE (GET_MODE (reg)) > GET_MODE_SIZE (mode))
        {
          push_to_sequence (before);
          lra_emit_move (new_reg, reg);
          before = get_insns ();
          end_sequence ();
        }
      if (type != OP_IN)
        {
          start_sequence ();
          lra_emit_move (reg, new_reg);
          emit_insn (after);
          after = get_insns ();
          end_sequence ();
        }
      SUBREG_REG (operand) = new_reg;
      lra_process_new_insns (curr_insn, before, after,
                             "Inserting subreg reload");
      return true;
    }
  return false;
}

/* Return TRUE if X refers for a hard register from SET.  */
static bool
uses_hard_regs_p (rtx x, HARD_REG_SET set)
{
  int i, j, x_hard_regno;
  enum machine_mode mode;
  const char *fmt;
  enum rtx_code code;

  if (x == NULL_RTX)
    return false;
  code = GET_CODE (x);
  mode = GET_MODE (x);
  if (code == SUBREG)
    {
      x = SUBREG_REG (x);
      code = GET_CODE (x);
      if (GET_MODE_SIZE (GET_MODE (x)) > GET_MODE_SIZE (mode))
        mode = GET_MODE (x);
    }
  
  if (REG_P (x))
    {
      x_hard_regno = get_hard_regno (x);
      return (x_hard_regno >= 0
              && overlaps_hard_reg_set_p (set, mode, x_hard_regno));
    }
  if (MEM_P (x))
    {
      struct address ad;
      enum machine_mode mode = GET_MODE (x);
      rtx *addr_loc = &XEXP (x, 0);

      extract_address_regs (mode, MEM_ADDR_SPACE (x), addr_loc, MEM, &ad);
      if (ad.base_reg_loc != NULL)
        {
          if (uses_hard_regs_p (*ad.base_reg_loc, set))
            return true;
        }
      if (ad.index_reg_loc != NULL)
        {
          if (uses_hard_regs_p (*ad.index_reg_loc, set))
            return true;
        }
    }
  fmt = GET_RTX_FORMAT (code);
  for (i = GET_RTX_LENGTH (code) - 1; i >= 0; i--)
    {
      if (fmt[i] == 'e')
        {
          if (uses_hard_regs_p (XEXP (x, i), set))
            return true;
        }
      else if (fmt[i] == 'E')
        {
          for (j = XVECLEN (x, i) - 1; j >= 0; j--)
            if (uses_hard_regs_p (XVECEXP (x, i, j), set))
              return true;
        }
    }
  return false;
}

/* Return true if OP is a spilled pseudo. */
static inline bool
spilled_pseudo_p (rtx op)
{
  return (REG_P (op)
          && REGNO (op) >= FIRST_PSEUDO_REGISTER && in_mem_p (REGNO (op)));
}

/* Return true if X is a general constant.  */
static inline bool
general_constant_p (rtx x)
{
  return CONSTANT_P (x) && (! flag_pic || LEGITIMATE_PIC_OPERAND_P (x));
}

/* Cost factor for each additional reload and maximal cost bound for
   insn reloads.  One might ask about such strange numbers.  Their
   values occurred historically from former reload pass.  */
#define LOSER_COST_FACTOR 6
#define MAX_OVERALL_COST_BOUND 600

/* Major function to choose the current insn alternative and what
   operands should be reloaded and how.  If ONLY_ALTERNATIVE is not
   negative we should consider only this alternative.  Return false if
   we can not choose the alternative or find how to reload the
   operands.  */
static bool
process_alt_operands (int only_alternative)
{
  bool ok_p = false;
  int nop, small_class_operands_num, overall, nalt;
  int n_alternatives = curr_static_id->n_alternatives;
  int n_operands = curr_static_id->n_operands;
  /* LOSERS counts the operands that don't fit this alternative and
     would require loading.  */
  int losers;
  /* REJECT is a count of how undesirable this alternative says it is
     if any reloading is required.  If the alternative matches exactly
     then REJECT is ignored, but otherwise it gets this much counted
     against it in addition to the reloading needed.  */
  int reject;
  /* The number of elements in the following array.  */
  int early_clobbered_regs_num;
  /* Numbers of operands which are early clobber registers.  */
  int early_clobbered_nops[MAX_RECOG_OPERANDS];
  enum reg_class curr_alt[MAX_RECOG_OPERANDS];
  HARD_REG_SET curr_alt_set[MAX_RECOG_OPERANDS];
  bool curr_alt_match_win[MAX_RECOG_OPERANDS];
  bool curr_alt_win[MAX_RECOG_OPERANDS];
  bool curr_alt_offmemok[MAX_RECOG_OPERANDS];
  int curr_alt_matches[MAX_RECOG_OPERANDS];
  /* The number of elements in the following array.  */
  int curr_alt_dont_inherit_ops_num;
  /* Numbers of operands whose reload pseudos should not be inherited.  */
  int curr_alt_dont_inherit_ops[MAX_RECOG_OPERANDS];
  rtx op;
  /* The register when the operand is a subreg of register, otherwise the
     operand itself.  */
  rtx no_subreg_reg_operand[MAX_RECOG_OPERANDS];
  /* The register if the operand is a register or subreg of register,
     otherwise NULL.  */
  rtx operand_reg[MAX_RECOG_OPERANDS];
  int hard_regno[MAX_RECOG_OPERANDS];
  enum machine_mode biggest_mode[MAX_RECOG_OPERANDS];
  int reload_nregs, reload_sum;
  bool costly_p;
  enum reg_class cl;

  /* Calculate some data common for all alternatives to speed up the
     function.  */
  for (nop = 0; nop < n_operands; nop++)
    {
      op = no_subreg_reg_operand[nop] = *curr_id->operand_loc[nop];
      /* The real hard regno of the operand after the allocation.  */
      hard_regno[nop] = get_hard_regno (op);
      
      operand_reg[nop] = op;
      biggest_mode[nop] = GET_MODE (operand_reg[nop]);
      if (GET_CODE (operand_reg[nop]) == SUBREG)
        {
          operand_reg[nop] = SUBREG_REG (operand_reg[nop]);
          if (GET_MODE_SIZE (biggest_mode[nop])
              < GET_MODE_SIZE (GET_MODE (operand_reg[nop])))
            biggest_mode[nop] = GET_MODE (operand_reg[nop]);
        }
      if (REG_P (operand_reg[nop]))
        no_subreg_reg_operand[nop] = operand_reg[nop];
      else
        operand_reg[nop] = NULL_RTX;
    }

  /* The constraints are made of several alternatives.  Each operand's
     constraint looks like foo,bar,... with commas separating the
     alternatives.  The first alternatives for all operands go
     together, the second alternatives go together, etc.

     First loop over alternatives.  */
  for (nalt = 0; nalt < n_alternatives; nalt++)
    {
      /* Loop over operands for one constraint alternative.  */
#ifdef HAVE_ATTR_enabled
      if (curr_id->alternative_enabled_p != NULL
          && ! curr_id->alternative_enabled_p[nalt])
        continue;
#endif

      if (only_alternative >= 0 && nalt != only_alternative)
        continue;

      overall = losers = reject = reload_nregs = reload_sum = 0;
      for (nop = 0; nop < n_operands; nop++)
        reject += (curr_static_id
                   ->operand_alternative[nalt * n_operands + nop].reject);
      early_clobbered_regs_num = 0;

      for (nop = 0; nop < n_operands; nop++)
        {
          const char *p;
          char *end;
          int len, c, m, i, opalt_num, this_alternative_matches;
          bool win, did_match, offmemok, early_clobber_p;
          /* false => this operand can be reloaded somehow for this
             alternative.  */
          bool badop;
          /* true => this operand can be reloaded if the alternative
             allows regs.  */
          bool winreg;
          /* True if a constant forced into memory would be OK for
             this operand.  */
          bool constmemok;
          enum reg_class this_alternative, this_costly_alternative;
          HARD_REG_SET this_alternative_set, this_costly_alternative_set;
          bool this_alternative_match_win, this_alternative_win;
          bool this_alternative_offmemok;
          enum machine_mode mode;

          opalt_num = nalt * n_operands + nop;
          if (curr_static_id->operand_alternative[opalt_num].anything_ok)
            {
              /* Fast track for no constraints at all.  */
              curr_alt[nop] = NO_REGS;
              CLEAR_HARD_REG_SET (curr_alt_set[nop]);
              curr_alt_win[nop] = true;
              curr_alt_match_win[nop] = false;
              curr_alt_offmemok[nop] = false;
              curr_alt_matches[nop] = -1;
              continue;
            }
      
          op = no_subreg_reg_operand[nop];
          mode = curr_operand_mode[nop];

          win = did_match = winreg = offmemok = constmemok = false;
          badop = true;
      
          early_clobber_p = false;
          p = curr_static_id->operand_alternative[opalt_num].constraint;
      
          this_costly_alternative = this_alternative = NO_REGS;
          /* We update set of possible hard regs besides its class
             because reg class might be inaccurate.  For example,
             union of LO_REGS (l), HI_REGS(h), and STACK_REG(k) in ARM
             is translated in HI_REGS because classes are merged by
             pairs and there is no accurate intermediate class.  */
          CLEAR_HARD_REG_SET (this_alternative_set);
          CLEAR_HARD_REG_SET (this_costly_alternative_set);
          this_alternative_win = false;
          this_alternative_match_win = false;
          this_alternative_offmemok = false;
          this_alternative_matches = -1;
  
          /* An empty constraint should be excluded by the fast
             track.  */
          lra_assert (*p != 0 && *p != ',');
  
          /* Scan this alternative's specs for this operand; set WIN
             if the operand fits any letter in this alternative.
             Otherwise, clear BADOP if this operand could fit some
             letter after reloads, or set WINREG if this operand could
             fit after reloads provided the constraint allows some
             registers.  */
          costly_p = false;
          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 ' ': case '\t':
                  break;
                  
                case '%':
                  /* We only support one commutative marker, the first
                     one.  We already set commutative above.  */
                  break;
                  
                case '&':
                  early_clobber_p = true;
                  break;
                  
                case '#':
                  /* Ignore rest of this alternative.  */
                  c = '\0';
                  break;
                  
                case '0':  case '1':  case '2':  case '3':  case '4':
                case '5':  case '6':  case '7':  case '8':  case '9':
                  {
                    int m_hregno;
                    bool match_p;
                    
                    m = strtoul (p, &end, 10);
                    p = end;
                    len = 0;
                    lra_assert (nop > m);
                    
                    this_alternative_matches = m;
                    m_hregno = get_hard_regno (*curr_id->operand_loc[m]);
                    /* We are supposed to match a previous operand.
                       If we do, we win if that one did.  If we do
                       not, count both of the operands as losers.
                       (This is too conservative, since most of the
                       time only a single reload insn will be needed
                       to make the two operands win.  As a result,
                       this alternative may be rejected when it is
                       actually desirable.)  */
                    match_p = false;
                    if (operands_match_p (*curr_id->operand_loc[nop],
                                          *curr_id->operand_loc[m], m_hregno))
                      {
                        /* We should reject matching of an early
                           clobber operand if the matching operand is
                           not dying in the insn.  */
                        if (! curr_static_id->operand[m].early_clobber
                            || operand_reg[nop] == NULL_RTX
                            || (find_regno_note (curr_insn, REG_DEAD,
                                                 REGNO (operand_reg[nop]))
                                                 != NULL_RTX))
                          match_p = true;
                      }
                    if (match_p)
                      {
                        /* If we are matching a non-offsettable
                           address where an offsettable address was
                           expected, then we must reject this
                           combination, because we can't reload
                           it.  */
                        if (curr_alt_offmemok[m]
                            && MEM_P (*curr_id->operand_loc[m])
                            && curr_alt[m] == NO_REGS && ! curr_alt_win[m])
                          continue;
                        
                      }
                    else
                      {
                        /* Operands don't match.  Both operands must
                           allow a reload register, otherwise we
                           cannot make them match.  */
                        if (curr_alt[m] == NO_REGS)
                          break;
                        /* Retroactively mark the operand we had to
                           match as a loser, if it wasn't already and
                           it wasn't matched to a register constraint
                           (e.g it might be matched by memory). */
                        if (curr_alt_win[m]
                            && (operand_reg[m] == NULL_RTX
                                || hard_regno[m] < 0))
                          {
                            losers++;
                            reload_nregs
                              += (ira_reg_class_max_nregs[curr_alt[m]]
                                  [GET_MODE (*curr_id->operand_loc[m])]);
                          }
                        
                        /* We prefer no matching alternatives because
                           it gives more freedom in RA.  */
                        if (operand_reg[nop] == NULL_RTX
                            || (find_regno_note (curr_insn, REG_DEAD,
                                                 REGNO (operand_reg[nop]))
                                 == NULL_RTX))
                          reject += 2;
                      }
                    /* If we have to reload this operand and some
                       previous operand also had to match the same
                       thing as this operand, we don't know how to do
                       that.  */
                    if (!match_p || !curr_alt_win[m])
                      {
                        for (i = 0; i < nop; i++)
                          if (curr_alt_matches[i] == m)
                            break;
                        if (i < nop)
                          break;
                      }
                    else
                      did_match = true;
                    
                    /* This can be fixed with reloads if the operand
                       we are supposed to match can be fixed with
                       reloads. */
                    badop = false;
                    this_alternative = curr_alt[m];
                    COPY_HARD_REG_SET (this_alternative_set, curr_alt_set[m]);
                    break;
                  }
                  
                case 'p':
                  cl = base_reg_class (VOIDmode, ADDR_SPACE_GENERIC,
                                       ADDRESS, SCRATCH);
                  this_alternative = reg_class_subunion[this_alternative][cl];
                  IOR_HARD_REG_SET (this_alternative_set,
                                    reg_class_contents[cl]);
                  if (costly_p)
                    {
                      this_costly_alternative
                        = reg_class_subunion[this_costly_alternative][cl];
                      IOR_HARD_REG_SET (this_costly_alternative_set,
                                        reg_class_contents[cl]);
                    }
                  win = true;
                  badop = false;
                  break;
                  
                case TARGET_MEM_CONSTRAINT:
                  if (MEM_P (op) || spilled_pseudo_p (op))
                    win = true;
                  if (CONST_POOL_OK_P (mode, op))
                    badop = false;
                  constmemok = true;
                  break;
                  
                case '<':
                  if (MEM_P (op)
                      && (GET_CODE (XEXP (op, 0)) == PRE_DEC
                          || GET_CODE (XEXP (op, 0)) == POST_DEC))
                    win = true;
                  break;
                  
                case '>':
                  if (MEM_P (op)
                      && (GET_CODE (XEXP (op, 0)) == PRE_INC
                          || GET_CODE (XEXP (op, 0)) == POST_INC))
                    win = true;
                  break;
                  
                  /* Memory op whose address is not offsettable.  */
                case 'V':
                  if (MEM_P (op)
                      && ! offsettable_nonstrict_memref_p (op))
                    win = true;
                  break;
                  
                  /* Memory operand whose address is offsettable.  */
                case 'o':
                  if ((MEM_P (op)
                       && offsettable_nonstrict_memref_p (op))
                      || spilled_pseudo_p (op))
                    win = true;
                  if (CONST_POOL_OK_P (mode, op) || MEM_P (op))
                    badop = false;
                  constmemok = true;
                  offmemok = true;
                  break;
                  
                case 'E':
                case 'F':
                  if (GET_CODE (op) == CONST_DOUBLE
                      || (GET_CODE (op) == CONST_VECTOR
                          && (GET_MODE_CLASS (mode) == MODE_VECTOR_FLOAT)))
                    win = true;
                  break;
                  
                case 'G':
                case 'H':
                  if (GET_CODE (op) == CONST_DOUBLE
                      && CONST_DOUBLE_OK_FOR_CONSTRAINT_P (op, c, p))
                    win = true;
                  break;
                  
                case 's':
                  if (CONST_INT_P (op)
                      || (GET_CODE (op) == CONST_DOUBLE && mode == VOIDmode))
                    break;
                case 'i':
                  if (general_constant_p (op))
                    win = true;
                  break;
                  
                case 'n':
                  if (CONST_INT_P (op)
                      || (GET_CODE (op) == CONST_DOUBLE && mode == VOIDmode))
                    win = true;
                  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 = true;
                  break;
                  
                case 'X':
                  /* This constraint should be excluded by the fast
                     track.  */
                  gcc_unreachable ();
                  break;
                  
                case 'g':
                  if (MEM_P (op)
                      || general_constant_p (op)
                      || spilled_pseudo_p (op))
                    win = true;
                  /* Drop through into 'r' case.  */
                  
                case 'r':
                  this_alternative
                    = reg_class_subunion[this_alternative][GENERAL_REGS];
                  IOR_HARD_REG_SET (this_alternative_set,
                                    reg_class_contents[GENERAL_REGS]);
                  if (costly_p)
                    {
                      this_costly_alternative
                        = (reg_class_subunion
                           [this_costly_alternative][GENERAL_REGS]);
                      IOR_HARD_REG_SET (this_costly_alternative_set,
                                        reg_class_contents[GENERAL_REGS]);
                    }
                  goto reg;
                  
                default:
                  if (REG_CLASS_FROM_CONSTRAINT (c, p) == NO_REGS)
                    {
#ifdef EXTRA_CONSTRAINT_STR
                      if (EXTRA_MEMORY_CONSTRAINT (c, p))
                        {
                          if (EXTRA_CONSTRAINT_STR (op, c, p))
                            win = true;
                          else if (spilled_pseudo_p (op))
                            win = true;
                          
                          /* If we didn't already win, we can reload
                             constants via force_const_mem, and other
                             MEMs by reloading the address like for
                             'o'.  */
                          if (CONST_POOL_OK_P (mode, op) || MEM_P (op))
                            badop = false;
                          constmemok = true;
                          offmemok = true;
                          break;
                        }
                      if (EXTRA_ADDRESS_CONSTRAINT (c, p))
                        {
                          if (EXTRA_CONSTRAINT_STR (op, c, p))
                            win = true;
                          
                          /* If we didn't already win, we can reload
                             the address into a base register.  */
                          cl = base_reg_class (VOIDmode, ADDR_SPACE_GENERIC,
                                               ADDRESS, SCRATCH);
                          this_alternative
                            = reg_class_subunion[this_alternative][cl];
                          IOR_HARD_REG_SET (this_alternative_set,
                                            reg_class_contents[cl]);
                          if (costly_p)
                            {
                              this_costly_alternative
                                = (reg_class_subunion
                                   [this_costly_alternative][cl]);
                              IOR_HARD_REG_SET (this_costly_alternative_set,
                                                reg_class_contents[cl]);
                            }
                          badop = false;
                          break;
                        }
                      
                      if (EXTRA_CONSTRAINT_STR (op, c, p))
                        win = true;
#endif
                      break;
                    }
                  
                  cl = REG_CLASS_FROM_CONSTRAINT (c, p);
                  this_alternative = reg_class_subunion[this_alternative][cl];
                  IOR_HARD_REG_SET (this_alternative_set,
                                    reg_class_contents[cl]);
                  if (costly_p)
                    {
                      this_costly_alternative
                        = reg_class_subunion[this_costly_alternative][cl];
                      IOR_HARD_REG_SET (this_costly_alternative_set,
                                        reg_class_contents[cl]);
                    }
                reg:
                  if (mode == BLKmode)
                    break;
                  winreg = true;
                  if (REG_P (op))
                    {
                      if (hard_regno[nop] >= 0
                          && in_hard_reg_set_p (this_alternative_set,
                                                mode, hard_regno[nop]))
                        win = true;
                      else if (hard_regno[nop] < 0
                               && in_class_p (op, this_alternative, NULL))
                        win = true;
                    }
                  break;
                }
              if (c != ' ' && c != '\t')
                costly_p = c == '*';
            }
          while ((p += len), c);
  
          /* Record which operands fit this alternative.  */
          if (win)
            {
              this_alternative_win = true;
              if (operand_reg[nop] != NULL_RTX)
                {
                  if (hard_regno[nop] >= 0)
                    {
                      if (in_hard_reg_set_p (this_costly_alternative_set,
                                             mode, hard_regno[nop]))
                        reject++;
                    }
                  else
                    {
                      /* Prefer won reg to spilled pseudo under other equal
                         conditions.  */
                      reject++;
                      if (in_class_p (operand_reg[nop],
                                      this_costly_alternative, NULL))
                        reject++;
                    }
                  /* We simulate the behaviour of old reload here.
                     Although scratches need hard registers and it
                     might result in spilling other pseudos, no reload
                     insns are generated for the scratches.  So it
                     might cost something but probably less than old
                     reload pass believes.  */
                  if (lra_former_scratch_p (REGNO (operand_reg[nop])))
                    reject += LOSER_COST_FACTOR;
                }
            }
          else if (did_match)
            this_alternative_match_win = true;
          else
            {
              int const_to_mem = 0;
              bool no_regs_p;

              no_regs_p
                = (this_alternative == NO_REGS
                   || (hard_reg_set_subset_p
                       (reg_class_contents[this_alternative],
                        lra_no_alloc_regs)));
              /* If this operand accepts a register, and if the
                 register class has at least one allocatable register,
                 then this operand can be reloaded.  */
              if (winreg && !no_regs_p)
                badop = false;
              
              if (badop)
                goto fail;

              this_alternative_offmemok = offmemok;
              if (this_costly_alternative != NO_REGS)
                reject++;
              /* If the operand is dying, has a matching constraint,
                 and satisfies constraints of the matched operand
                 which failed to satisfy the own constraints, we do
                 not need to generate a reload insn for this
                 operand.  */
              if (!(this_alternative_matches >= 0
                    && !curr_alt_win[this_alternative_matches]
                    && REG_P (op)
                    && find_regno_note (curr_insn, REG_DEAD, REGNO (op))
                    && (hard_regno[nop] >= 0
                        ? in_hard_reg_set_p (this_alternative_set,
                                             mode, hard_regno[nop])
                        : in_class_p (op, this_alternative, NULL))))
                losers++;
              if (operand_reg[nop] != NULL_RTX
                  /* Output operands and matched input operands are
                     not inherited.  The following conditions do not
                     exactly describe the previous statement but they
                     are pretty close.  */
                  && curr_static_id->operand[nop].type != OP_OUT
                  && (this_alternative_matches < 0
                      || curr_static_id->operand[nop].type != OP_IN))
                {
                  int last_reload = (lra_reg_info[ORIGINAL_REGNO
                                                  (operand_reg[nop])]
                                     .last_reload);

                  if (last_reload > bb_reload_num)
                    reload_sum += last_reload - bb_reload_num;
                }
              /* If this is a constant that is reloaded into the
                 desired class by copying it to memory first, count
                 that as another reload.  This is consistent with
                 other code and is required to avoid choosing another
                 alternative when the constant is moved into memory.
                 Note that the test here is precisely the same as in
                 the code below that calls force_const_mem.  */
              if (CONST_POOL_OK_P (mode, op)
                  && ((targetm.preferred_reload_class
                       (op, this_alternative) == NO_REGS)
                      || no_input_reloads_p))
                {
                  const_to_mem = 1;
                  if (! no_regs_p)
                    losers++;
                }
      
              /* Alternative loses if it requires a type of reload not
                 permitted for this insn.  We can always reload
                 objects with a REG_UNUSED note.  */
              if ((curr_static_id->operand[nop].type != OP_IN
                   && no_output_reloads_p
                   && ! find_reg_note (curr_insn, REG_UNUSED, op))
                  || (curr_static_id->operand[nop].type != OP_OUT
                      && no_input_reloads_p && ! const_to_mem))
                goto fail;
      
              /* If we can't reload this value at all, reject this
                 alternative.  Note that we could also lose due to
                 LIMIT_RELOAD_CLASS, but we don't check that here.  */
              if (! CONSTANT_P (op) && ! no_regs_p)
                {
                  if (targetm.preferred_reload_class
                      (op, this_alternative) == NO_REGS)
                    reject = MAX_OVERALL_COST_BOUND;
          
                  if (curr_static_id->operand[nop].type == OP_OUT
                      && (targetm.preferred_output_reload_class
                          (op, this_alternative) == NO_REGS))
                    reject = MAX_OVERALL_COST_BOUND;
                }
      
              if (! ((const_to_mem && constmemok)
                     || (MEM_P (op) && offmemok)))
                {
                  /* We prefer to reload pseudos over reloading other
                     things, since such reloads may be able to be
                     eliminated later.  So bump REJECT in other cases.
                     Don't do this in the case where we are forcing a
                     constant into memory and it will then win since
                     we don't want to have a different alternative
                     match then.  */
                  if (! (REG_P (op) && REGNO (op) >= FIRST_PSEUDO_REGISTER))
                    reject += 2;
                  
                  if (! no_regs_p)
                    reload_nregs
                      += ira_reg_class_max_nregs[this_alternative][mode];
                }

              /* Input reloads can be inherited more often than output
                 reloads can be removed, so penalize output
                 reloads.  */
              if (!REG_P (op) || curr_static_id->operand[nop].type != OP_IN)
                reject++;
            }
  
          if (early_clobber_p)
            reject++;
          /* ??? We check early clobbers after processing all operands
             (see loop below) and there we update the costs more.
             Should we update the cost (may be approximately) here
             because of early clobber register reloads or it is a rare
             or non-important thing to be worth to do it.  */
          overall = losers * LOSER_COST_FACTOR + reject;
          if ((best_losers == 0 || losers != 0) && best_overall < overall)
            goto fail;

          curr_alt[nop] = this_alternative;
          COPY_HARD_REG_SET (curr_alt_set[nop], this_alternative_set);
          curr_alt_win[nop] = this_alternative_win;
          curr_alt_match_win[nop] = this_alternative_match_win;
          curr_alt_offmemok[nop] = this_alternative_offmemok;
          curr_alt_matches[nop] = this_alternative_matches;
  
          if (this_alternative_matches >= 0
              && !did_match && !this_alternative_win)
            curr_alt_win[this_alternative_matches] = false;
  
          if (early_clobber_p && operand_reg[nop] != NULL_RTX)
            early_clobbered_nops[early_clobbered_regs_num++] = nop;
        }
      ok_p = true;
      curr_alt_dont_inherit_ops_num = 0;
      for (nop = 0; nop < early_clobbered_regs_num; nop++)
        {
          int i, j, clobbered_hard_regno;
          HARD_REG_SET temp_set;

          i = early_clobbered_nops[nop];
          if ((! curr_alt_win[i] && ! curr_alt_match_win[i])
              || hard_regno[i] < 0)
            continue;
          clobbered_hard_regno = hard_regno[i];
          CLEAR_HARD_REG_SET (temp_set);
          add_to_hard_reg_set (&temp_set, biggest_mode[i], clobbered_hard_regno);
          for (j = 0; j < n_operands; j++)
            if (j == i
                /* We don't want process insides of match_operator and
                   match_parallel because otherwise we would process
                   their operands once again generating a wrong
                   code.  */
                || curr_static_id->operand[j].is_operator)
              continue;
            else if ((curr_alt_matches[j] == i && curr_alt_match_win[j])
                     || (curr_alt_matches[i] == j && curr_alt_match_win[i]))
              continue;
            else if (uses_hard_regs_p (*curr_id->operand_loc[j], temp_set))
              break;
          if (j >= n_operands)
            continue;
          /* We need to reload early clobbered register.  */
          for (j = 0; j < n_operands; j++)
            if (curr_alt_matches[j] == i)
              {
                curr_alt_match_win[j] = false;
                losers++;
                overall += LOSER_COST_FACTOR;
              }
          if (! curr_alt_match_win[i])
            curr_alt_dont_inherit_ops[curr_alt_dont_inherit_ops_num++] = i;
          else
            {
              /* Remember pseudos used for match reloads are never
                 inherited.  */
              lra_assert (curr_alt_matches[i] >= 0);
              curr_alt_win[curr_alt_matches[i]] = false;
            }
          curr_alt_win[i] = curr_alt_match_win[i] = false;
          losers++;
          overall += LOSER_COST_FACTOR;
        }
      small_class_operands_num = 0;
      for (nop = 0; nop < n_operands; nop++)
        small_class_operands_num
          += SMALL_REGISTER_CLASS_P (curr_alt[nop]) ? 1 : 0;

      /* If this alternative can be made to work by reloading, and it
         needs less reloading than the others checked so far, record
         it as the chosen goal for reloading.  */
      if ((best_losers != 0 && losers == 0)
          || (((best_losers == 0 && losers == 0)
               || (best_losers != 0 && losers != 0))
              && (best_overall > overall
                  || (best_overall == overall
                      /* If the cost of the reloads is the same,
                         prefer alternative which requires minimal
                         number of small register classes for the
                         operands.  This improves chances of reloads
                         for insn requiring small register
                         classes.  */
                      && (small_class_operands_num
                          < best_small_class_operands_num
                          || (small_class_operands_num
                              == best_small_class_operands_num
                              && (reload_nregs < best_reload_nregs
                                  || (reload_nregs == best_reload_nregs
                                      && best_reload_sum < reload_sum))))))))
        {
          for (nop = 0; nop < n_operands; nop++)
            {
              goal_alt_win[nop] = curr_alt_win[nop];
              goal_alt_match_win[nop] = curr_alt_match_win[nop];
              goal_alt_matches[nop] = curr_alt_matches[nop];
              goal_alt[nop] = curr_alt[nop];
              goal_alt_offmemok[nop] = curr_alt_offmemok[nop];
            }
          goal_alt_dont_inherit_ops_num = curr_alt_dont_inherit_ops_num;
          for (nop = 0; nop < curr_alt_dont_inherit_ops_num; nop++)
            goal_alt_dont_inherit_ops[nop] = curr_alt_dont_inherit_ops[nop];
          goal_alt_swapped = curr_swapped;
          best_overall = overall;
          best_losers = losers;
          best_small_class_operands_num = small_class_operands_num;
          best_reload_nregs = reload_nregs;
          best_reload_sum = reload_sum;
          goal_alt_number = nalt;
        }
      if (losers == 0)
        /* Everything is satisfied.  Do not process alternatives
           anymore.  */ 
        break;
    fail:
      ;
    }
  return ok_p;
}

/* Return 1 if ADDR is a valid memory address for mode MODE in address
   space AS, and check that each pseudo has the proper kind of hard
   reg.  */
static int
valid_address_p (enum machine_mode mode ATTRIBUTE_UNUSED,
                 rtx addr, addr_space_t as)
{
#ifdef GO_IF_LEGITIMATE_ADDRESS
  lra_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
}

/* Make reload base reg + disp from address AD in space AS of memory
   with MODE into a new pseudo.  Return the new pseudo.  */
static rtx
base_plus_disp_to_reg (enum machine_mode mode, addr_space_t as,
                       struct address *ad)
{
  enum reg_class cl;
  rtx new_reg;

  lra_assert (ad->base_reg_loc != NULL && ad->disp_loc != NULL);
  cl = base_reg_class (mode, as, ad->base_outer_code, ad->index_code);
  new_reg = lra_create_new_reg (Pmode, NULL_RTX, cl, "base + disp");
  lra_emit_add (new_reg, *ad->base_reg_loc, *ad->disp_loc);
  return new_reg;
}

/* Make substitution in address AD in space AS with location ADDR_LOC.
   Update AD and ADDR_LOC if it is necessary.  Return true if a
   substitution was made.  */
static bool
equiv_address_substitution (struct address *ad, rtx *addr_loc,
                            enum machine_mode mode, addr_space_t as,
                            enum rtx_code code)
{
  rtx base_reg, new_base_reg, index_reg, new_index_reg;
  HOST_WIDE_INT disp, scale;
  bool change_p;

  if (ad->base_reg_loc == NULL)
    base_reg = new_base_reg = NULL_RTX;
  else
    {
      base_reg = *ad->base_reg_loc;
      new_base_reg = get_equiv_substitution (base_reg);
    }
  if (ad->index_reg_loc == NULL)
    index_reg = new_index_reg = NULL_RTX;
  else
    {
      index_reg = *ad->index_reg_loc;
      new_index_reg = get_equiv_substitution (index_reg);
    }
  if (base_reg == new_base_reg && index_reg == new_index_reg)
    return false;
  disp = 0;
  change_p = false;
  if (lra_dump_file != NULL)
    {
      fprintf (lra_dump_file, "Changing address in insn %d ",
               INSN_UID (curr_insn));
      print_value_slim (lra_dump_file, *addr_loc, 1);
    }
  if (base_reg != new_base_reg)
    {
      if (REG_P (new_base_reg))
        {
          *ad->base_reg_loc = new_base_reg;
          change_p = true;
        }
      else if (GET_CODE (new_base_reg) == PLUS
               && REG_P (XEXP (new_base_reg, 0))
               && CONST_INT_P (XEXP (new_base_reg, 1)))
        {
          disp += INTVAL (XEXP (new_base_reg, 1));
          *ad->base_reg_loc = XEXP (new_base_reg, 0);
          change_p = true;
        }
      if (ad->base_reg_loc2 != NULL)
        *ad->base_reg_loc2 = *ad->base_reg_loc;
    }
  scale = 1;
  if (ad->index_loc != NULL && GET_CODE (*ad->index_loc) == MULT)
    {
      lra_assert (CONST_INT_P (XEXP (*ad->index_loc, 1)));
      scale = INTVAL (XEXP (*ad->index_loc, 1));
    }
  if (index_reg != new_index_reg)
    {
      if (REG_P (new_index_reg))
        {
          *ad->index_reg_loc = new_index_reg;
          change_p = true;
        }
      else if (GET_CODE (new_index_reg) == PLUS
               && REG_P (XEXP (new_index_reg, 0))
               && CONST_INT_P (XEXP (new_index_reg, 1)))
        {
          disp += INTVAL (XEXP (new_index_reg, 1)) * scale;
          *ad->index_reg_loc = XEXP (new_index_reg, 0);
          change_p = true;
        }
    }
  if (disp != 0)
    {
      if (ad->disp_loc != NULL)
        *ad->disp_loc = plus_constant (Pmode, *ad->disp_loc, disp);
      else
        {
          *addr_loc = gen_rtx_PLUS (Pmode, *addr_loc, GEN_INT (disp));
          extract_address_regs (mode, as, addr_loc, code, ad);
        }
      change_p = true;
    }
  if (lra_dump_file != NULL)
    {
      if (! change_p)
        fprintf (lra_dump_file, " -- no change\n");
      else
        {
          fprintf (lra_dump_file, " on equiv ");
          print_value_slim (lra_dump_file, *addr_loc, 1);
          fprintf (lra_dump_file, "\n");
        }
    }
  return change_p;
}

/* Major function to make reloads for address in operand NOP.  Add to
   reloads to the list *BEFORE and *AFTER.  We might need to add
   reloads to *AFTER because of inc/dec, {pre, post} modify in the
   address.  Return true for any RTL change.  */
static bool
process_address (int nop, rtx *before, rtx *after)
{
  struct address ad;
  enum machine_mode mode;
  rtx new_reg, *addr_loc, saved_index_reg, saved_base_reg;
  bool ok_p;
  addr_space_t as;
  rtx op = *curr_id->operand_loc[nop];
  const char *constraint = curr_static_id->operand[nop].constraint;
  bool change_p;
  enum rtx_code code;

  if (constraint[0] == 'p'
      || EXTRA_ADDRESS_CONSTRAINT (constraint[0], constraint))
    {
      mode = VOIDmode;
      addr_loc = curr_id->operand_loc[nop];
      as = ADDR_SPACE_GENERIC;
      code = ADDRESS;
    }
  else if (MEM_P (op))
    {
      mode = GET_MODE (op);
      addr_loc = &XEXP (op, 0);
      as = MEM_ADDR_SPACE (op);
      code = MEM;
    }
  else if (GET_CODE (op) == SUBREG
           && MEM_P (SUBREG_REG (op)))
    {
      mode = GET_MODE (SUBREG_REG (op));
      addr_loc = &XEXP (SUBREG_REG (op), 0);
      as = MEM_ADDR_SPACE (SUBREG_REG (op));
      code = MEM;
    }
  else
    return false;
  if (GET_CODE (*addr_loc) == AND)
    addr_loc = &XEXP (*addr_loc, 0);
  extract_address_regs (mode, as, addr_loc, code, &ad);
  change_p = equiv_address_substitution (&ad, addr_loc, mode, as, code);
  if (ad.base_reg_loc != NULL
      && (process_addr_reg
          (ad.base_reg_loc, before,
           (ad.base_modify_p && REG_P (*ad.base_reg_loc)
            && find_regno_note (curr_insn, REG_DEAD,
                                REGNO (*ad.base_reg_loc)) == NULL_RTX
            ? after : NULL),
           base_reg_class (mode, as, ad.base_outer_code, ad.index_code))))
    {
      change_p = true;
      if (ad.base_reg_loc2 != NULL)
        *ad.base_reg_loc2 = *ad.base_reg_loc;
    }
  if (ad.index_reg_loc != NULL
      && process_addr_reg (ad.index_reg_loc, before, NULL, INDEX_REG_CLASS))
    change_p = true;

  /* The address was valid before LRA.  We only change its form if the
     address has a displacement, so if it has no displacement it must
     still be valid.  */
  if (ad.disp_loc == NULL)
    return change_p;

  /* See whether the address is still valid.  Some ports do not check
     displacements for eliminable registers, so we replace them
     temporarily with the elimination target.  */
  saved_base_reg = saved_index_reg = NULL_RTX;
  if (ad.base_reg_loc != NULL)
    {
      saved_base_reg = *ad.base_reg_loc;
      lra_eliminate_reg_if_possible (ad.base_reg_loc);
      if (ad.base_reg_loc2 != NULL)
        *ad.base_reg_loc2 = *ad.base_reg_loc;
    }
  if (ad.index_reg_loc != NULL)
    {
      saved_index_reg = *ad.index_reg_loc;
      lra_eliminate_reg_if_possible (ad.index_reg_loc);
    }
  /* Some ports do not check displacements for virtual registers -- so
     we substitute them temporarily by real registers.  */
  ok_p = valid_address_p (mode, *addr_loc, as);
  if (saved_base_reg != NULL_RTX)
    {
      *ad.base_reg_loc = saved_base_reg;
      if (ad.base_reg_loc2 != NULL)
        *ad.base_reg_loc2 = saved_base_reg;
    }
  if (saved_index_reg != NULL_RTX)
    *ad.index_reg_loc = saved_index_reg;

  if (ok_p)
    return change_p;

  /* Addresses were legitimate before LRA.  So if the address has
     two registers than it can have two of them.  We should also
     not worry about scale for the same reason.  */
  push_to_sequence (*before);
  if (ad.base_reg_loc == NULL)
    {
      if (ad.index_reg_loc == NULL)
        {
          int code = -1;
          enum reg_class cl = base_reg_class (mode, as, SCRATCH, SCRATCH);
          
          new_reg = lra_create_new_reg (Pmode, NULL_RTX, cl, "disp");
#ifdef HAVE_lo_sum
          {
            rtx insn;
            rtx last = get_last_insn ();

            /* disp => lo_sum (new_base, disp)  */
            insn = emit_insn (gen_rtx_SET
                              (VOIDmode, new_reg,
                               gen_rtx_HIGH (Pmode, copy_rtx (*ad.disp_loc))));
            code = recog_memoized (insn);
            if (code >= 0)
              {
                rtx save = *ad.disp_loc;

                *ad.disp_loc = gen_rtx_LO_SUM (Pmode, new_reg, *ad.disp_loc);
                if (! valid_address_p (mode, *ad.disp_loc, as))
                  {
                    *ad.disp_loc = save;
                    code = -1;
                  }
              }
            if (code < 0)
              delete_insns_since (last);
          }
#endif
          if (code < 0)
            {
              /* disp => new_base  */
              lra_emit_move (new_reg, *ad.disp_loc);
              *ad.disp_loc = new_reg;
            }
        }
      else
        {
          /* index * scale + disp => new base + index * scale  */
          enum reg_class cl = base_reg_class (mode, as, SCRATCH, SCRATCH);

          lra_assert (INDEX_REG_CLASS != NO_REGS);
          new_reg = lra_create_new_reg (Pmode, NULL_RTX, cl, "disp");
          lra_assert (GET_CODE (*addr_loc) == PLUS);
          lra_emit_move (new_reg, *ad.disp_loc);
          if (CONSTANT_P (XEXP (*addr_loc, 1)))
            XEXP (*addr_loc, 1) = XEXP (*addr_loc, 0);
          XEXP (*addr_loc, 0) = new_reg;
        }
    }
  else if (ad.index_reg_loc == NULL)
    {
      /* base + disp => new base  */
      /* Another option would be to reload the displacement into an
         index register.  However, postreload has code to optimize
         address reloads that have the same base and different
         displacements, so reloading into an index register would
         not necessarily be a win.  */
      new_reg = base_plus_disp_to_reg (mode, as, &ad);
      *addr_loc = new_reg;
    }
  else
    {
      /* base + scale * index + disp => new base + scale * index  */
      new_reg = base_plus_disp_to_reg (mode, as, &ad);
      *addr_loc = gen_rtx_PLUS (Pmode, new_reg, *ad.index_loc);
    }
  *before = get_insns ();
  end_sequence ();
  return true;
}

/* Emit insns to reload VALUE into a new register.  VALUE is an
   auto-increment or auto-decrement RTX whose operand is a register or
   memory location; so reloading involves incrementing that location.
   IN is either identical to VALUE, or some cheaper place to reload
   value being incremented/decremented from.

   INC_AMOUNT is the number to increment or decrement by (always
   positive and ignored for POST_MODIFY/PRE_MODIFY).

   Return pseudo containing the result.  */
static rtx
emit_inc (enum reg_class new_rclass, rtx in, rtx value, int inc_amount)
{
  /* REG or MEM to be copied and incremented.  */
  rtx incloc = XEXP (value, 0);
  /* Nonzero if increment after copying.  */
  int post = (GET_CODE (value) == POST_DEC || GET_CODE (value) == POST_INC
              || GET_CODE (value) == POST_MODIFY);
  rtx last;
  rtx inc;
  rtx add_insn;
  int code;
  rtx real_in = in == value ? incloc : in;
  rtx result;
  bool plus_p = true;

  if (GET_CODE (value) == PRE_MODIFY || GET_CODE (value) == POST_MODIFY)
    {
      lra_assert (GET_CODE (XEXP (value, 1)) == PLUS
                  || GET_CODE (XEXP (value, 1)) == MINUS);
      lra_assert (rtx_equal_p (XEXP (XEXP (value, 1), 0), XEXP (value, 0)));
      plus_p = GET_CODE (XEXP (value, 1)) == PLUS;
      inc = XEXP (XEXP (value, 1), 1);
    }
  else
    {
      if (GET_CODE (value) == PRE_DEC || GET_CODE (value) == POST_DEC)
        inc_amount = -inc_amount;

      inc = GEN_INT (inc_amount);
    }

  if (! post && REG_P (incloc))
    result = incloc;
  else
    result = lra_create_new_reg (GET_MODE (value), value, new_rclass,
                                 "INC/DEC result");

  if (real_in != result)
    {
      /* First copy the location to the result register.  */
      lra_assert (REG_P (result));
      emit_insn (gen_move_insn (result, real_in));
    }

  /* We suppose that there are insns to add/sub with the constant
     increment permitted in {PRE/POST)_{DEC/INC/MODIFY}.  At least the
     old reload worked with this assumption.  If the assumption
     becomes wrong, we should use approach in function
     base_plus_disp_to_reg.  */
  if (in == value)
    {
      /* See if we can directly increment INCLOC.  */
      last = get_last_insn ();
      add_insn = emit_insn (plus_p
                            ? gen_add2_insn (incloc, inc)
                            : gen_sub2_insn (incloc, inc));

      code = recog_memoized (add_insn);
      if (code >= 0)
        {
          if (! post && result != incloc)
            emit_insn (gen_move_insn (result, incloc));
          return result;
        }
      delete_insns_since (last);
    }

  /* If couldn't do the increment directly, must increment in RESULT.
     The way we do this depends on whether this is pre- or
     post-increment.  For pre-increment, copy INCLOC to the reload
     register, increment it there, then save back.  */
  if (! post)
    {
      if (real_in != result)
        emit_insn (gen_move_insn (result, real_in));
      if (plus_p)
        emit_insn (gen_add2_insn (result, inc));
      else
        emit_insn (gen_sub2_insn (result, inc));
      if (result != incloc)
        emit_insn (gen_move_insn (incloc, result));
    }
  else
    {
      /* Post-increment.

         Because this might be a jump insn or a compare, and because
         RESULT may not be available after the insn in an input
         reload, we must do the incrementing before the insn being
         reloaded for.

         We have already copied IN to RESULT.  Increment the copy in
         RESULT, save that back, then decrement RESULT so it has
         the original value.  */
      if (plus_p)
        emit_insn (gen_add2_insn (result, inc));
      else
        emit_insn (gen_sub2_insn (result, inc));
      emit_insn (gen_move_insn (incloc, result));
      /* Restore non-modified value for the result.  We prefer this
         way because it does not require an additional hard
         register.  */
      if (plus_p)
        {
          if (CONST_INT_P (inc))
            emit_insn (gen_add2_insn (result, GEN_INT (-INTVAL (inc))));
          else
            emit_insn (gen_sub2_insn (result, inc));
        }
      else
        emit_insn (gen_add2_insn (result, inc));
    }
  return result;
}

/* Swap operands NOP and NOP + 1. */
static inline void
swap_operands (int nop)
{
  enum machine_mode mode = curr_operand_mode[nop];
  curr_operand_mode[nop] = curr_operand_mode[nop + 1];
  curr_operand_mode[nop + 1] = mode;
  rtx x = *curr_id->operand_loc[nop];
  *curr_id->operand_loc[nop] = *curr_id->operand_loc[nop + 1];
  *curr_id->operand_loc[nop + 1] = x;
  /* Swap the duplicates too.  */
  lra_update_dup (curr_id, nop);
  lra_update_dup (curr_id, nop + 1);
}

/* Main entry point of the constraint code: search the body of the
   current insn to choose the best alternative.  It is mimicking insn
   alternative cost calculation model of former reload pass.  That is
   because machine descriptions were written to use this model.  This
   model can be changed in future.  Make commutative operand exchange
   if it is chosen.

   Return true if some RTL changes happened during function call.  */
static bool
curr_insn_transform (void)
{
  int i, j, k;
  int n_operands;
  int n_alternatives;
  int commutative;
  signed char goal_alt_matched[MAX_RECOG_OPERANDS][MAX_RECOG_OPERANDS];
  rtx before, after;
  bool alt_p = false;
  /* Flag that the insn has been changed through a transformation.  */
  bool change_p;
  bool sec_mem_p;
#ifdef SECONDARY_MEMORY_NEEDED
  bool use_sec_mem_p;
#endif
  int max_regno_before;
  int reused_alternative_num;

  no_input_reloads_p = no_output_reloads_p = false;
  goal_alt_number = -1;

  if (check_and_process_move (&change_p, &sec_mem_p))
    return change_p;

  /* JUMP_INSNs and CALL_INSNs are not allowed to have any output
     reloads; neither are insns that SET cc0.  Insns that use CC0 are
     not allowed to have any input reloads.  */
  if (JUMP_P (curr_insn) || CALL_P (curr_insn))
    no_output_reloads_p = true;

#ifdef HAVE_cc0
  if (reg_referenced_p (cc0_rtx, PATTERN (curr_insn)))
    no_input_reloads_p = true;
  if (reg_set_p (cc0_rtx, PATTERN (curr_insn)))
    no_output_reloads_p = true;
#endif

  n_operands = curr_static_id->n_operands;
  n_alternatives = curr_static_id->n_alternatives;

  /* Just return "no reloads" if insn has no operands with
     constraints.  */
  if (n_operands == 0 || n_alternatives == 0)
    return false;

  max_regno_before = max_reg_num ();

  for (i = 0; i < n_operands; i++)
    {
      goal_alt_matched[i][0] = -1;
      goal_alt_matches[i] = -1;
    }

  commutative = curr_static_id->commutative;

  /* Now see what we need for pseudos that didn't get hard regs or got
     the wrong kind of hard reg.  For this, we must consider all the
     operands together against the register constraints.  */

  best_losers = best_overall = MAX_RECOG_OPERANDS * 2 + MAX_OVERALL_COST_BOUND;
  best_small_class_operands_num = best_reload_sum = 0;

  curr_swapped = false;
  goal_alt_swapped = false;

  /* Make equivalence substitution and memory subreg elimination
     before address processing because an address legitimacy can
     depend on memory mode.  */
  for (i = 0; i < n_operands; i++)
    {
      rtx op = *curr_id->operand_loc[i];
      rtx subst, old = op;
      bool op_change_p = false;

      if (GET_CODE (old) == SUBREG)
        old = SUBREG_REG (old);
      subst = get_equiv_substitution (old);
      if (subst != old)
        {
          subst = copy_rtx (subst);
          lra_assert (REG_P (old));
          if (GET_CODE (op) == SUBREG)
            SUBREG_REG (op) = subst;
          else
            *curr_id->operand_loc[i] = subst;
          if (lra_dump_file != NULL)
            {
              fprintf (lra_dump_file,
                       "Changing pseudo %d in operand %i of insn %u on equiv ",
                       REGNO (old), i, INSN_UID (curr_insn));
              print_value_slim (lra_dump_file, subst, 1);
              fprintf (lra_dump_file, "\n");
            }
          op_change_p = change_p = true;
        }
      if (simplify_operand_subreg (i, GET_MODE (old)) || op_change_p)
        {
          change_p = true;
          lra_update_dup (curr_id, i);
        }
    }

  /* Reload address registers and displacements.  We do it before
     finding an alternative because of memory constraints.  */
  before = after = NULL_RTX;
  for (i = 0; i < n_operands; i++)
    if (! curr_static_id->operand[i].is_operator
        && process_address (i, &before, &after))
      {
        change_p = true;
        lra_update_dup (curr_id, i);
      }
  
  if (change_p)
    /* If we've changed the instruction then any alternative that
       we chose previously may no longer be valid.  */
    lra_set_used_insn_alternative (curr_insn, -1);

 try_swapped:

  reused_alternative_num = curr_id->used_insn_alternative;
  if (lra_dump_file != NULL && reused_alternative_num >= 0)
    fprintf (lra_dump_file, "Reusing alternative %d for insn #%u\n",
             reused_alternative_num, INSN_UID (curr_insn));

  if (process_alt_operands (reused_alternative_num))
    alt_p = true;

  /* If insn is commutative (it's safe to exchange a certain pair of
     operands) then we need to try each alternative twice, the second
     time matching those two operands as if we had exchanged them.  To
     do this, really exchange them in operands.

     If we have just tried the alternatives the second time, return
     operands to normal and drop through.  */

  if (reused_alternative_num < 0 && commutative >= 0)
    {
      curr_swapped = !curr_swapped;
      if (curr_swapped)
        {
          swap_operands (commutative);
          goto try_swapped;
        }
      else
        swap_operands (commutative);
    }

  /* The operands don't meet the constraints.  goal_alt describes the
     alternative that we could reach by reloading the fewest operands.
     Reload so as to fit it.  */

  if (! alt_p && ! sec_mem_p)
    {
      /* No alternative works with reloads??  */
      if (INSN_CODE (curr_insn) >= 0)
        fatal_insn ("unable to generate reloads for:", curr_insn);
      error_for_asm (curr_insn,
                     "inconsistent operand constraints in an %<asm%>");
      /* Avoid further trouble with this insn.  */
      PATTERN (curr_insn) = gen_rtx_USE (VOIDmode, const0_rtx);
      lra_invalidate_insn_data (curr_insn);
      return true;
    }

  /* If the best alternative is with operands 1 and 2 swapped, swap
     them.  Update the operand numbers of any reloads already
     pushed.  */

  if (goal_alt_swapped)
    {
      if (lra_dump_file != NULL)
        fprintf (lra_dump_file, "  Commutative operand exchange in insn %u\n",
                 INSN_UID (curr_insn));

      /* Swap the duplicates too.  */
      swap_operands (commutative);
      change_p = true;
    }

#ifdef SECONDARY_MEMORY_NEEDED
  /* Some target macros SECONDARY_MEMORY_NEEDED (e.g. x86) are defined
     too conservatively.  So we use the secondary memory only if there
     is no any alternative without reloads.  */
  use_sec_mem_p = false;
  if (! alt_p)
    use_sec_mem_p = true;
  else if (sec_mem_p)
    {
      for (i = 0; i < n_operands; i++)
        if (! goal_alt_win[i] && ! goal_alt_match_win[i])
          break;
      use_sec_mem_p = i < n_operands;
    }

  if (use_sec_mem_p)
    {
      rtx new_reg, set, src, dest;
      enum machine_mode sec_mode;

      lra_assert (sec_mem_p);
      set = single_set (curr_insn);
      lra_assert (set != NULL_RTX && ! side_effects_p (set));
      dest = SET_DEST (set);
      src = SET_SRC (set);
#ifdef SECONDARY_MEMORY_NEEDED_MODE
      sec_mode = SECONDARY_MEMORY_NEEDED_MODE (GET_MODE (src));
#else
      sec_mode = GET_MODE (src);
#endif
      new_reg = lra_create_new_reg (sec_mode, NULL_RTX,
                                    NO_REGS, "secondary");
      /* If the mode is changed, it should be wider.  */
      lra_assert (GET_MODE_SIZE (GET_MODE (new_reg))
                  >= GET_MODE_SIZE (GET_MODE (src)));
      after = emit_spill_move (false, new_reg, dest);
      lra_process_new_insns (curr_insn, NULL_RTX, after,
                             "Inserting the sec. move");
      before = emit_spill_move (true, new_reg, src);
      lra_process_new_insns (curr_insn, before, NULL_RTX, "Changing on");
      lra_set_insn_deleted (curr_insn);
      return true;
    }
#endif

  lra_assert (goal_alt_number >= 0);
  lra_set_used_insn_alternative (curr_insn, goal_alt_number);

  if (lra_dump_file != NULL)
    {
      const char *p;

      fprintf (lra_dump_file, "  Choosing alt %d in insn %u:",
               goal_alt_number, INSN_UID (curr_insn));
      for (i = 0; i < n_operands; i++)
        {
          p = (curr_static_id->operand_alternative
               [goal_alt_number * n_operands + i].constraint);
          if (*p == '\0')
            continue;
          fprintf (lra_dump_file, "  (%d) ", i);
          for (; *p != '\0' && *p != ',' && *p != '#'; p++)
            fputc (*p, lra_dump_file);
        }
      fprintf (lra_dump_file, "\n");
    }

  /* Right now, for any pair of operands I and J that are required to
     match, with J < I, goal_alt_matches[I] is J.  Add I to
     goal_alt_matched[J].  */
  
  for (i = 0; i < n_operands; i++)
    if ((j = goal_alt_matches[i]) >= 0)
      {
        for (k = 0; goal_alt_matched[j][k] >= 0; k++)
          ;
        /* We allow matching one output operand and several input
           operands.  */
        lra_assert (k == 0
                    || (curr_static_id->operand[j].type == OP_OUT
                        && curr_static_id->operand[i].type == OP_IN
                        && (curr_static_id->operand
                            [goal_alt_matched[j][0]].type == OP_IN)));
        goal_alt_matched[j][k] = i;
        goal_alt_matched[j][k + 1] = -1;
      }
  
  for (i = 0; i < n_operands; i++)
    goal_alt_win[i] |= goal_alt_match_win[i];
  
  /* Any constants that aren't allowed and can't be reloaded into
     registers are here changed into memory references.  */
  for (i = 0; i < n_operands; i++)
    if (goal_alt_win[i])
      {
        int regno;
        enum reg_class new_class;
        rtx reg = *curr_id->operand_loc[i];

        if (GET_CODE (reg) == SUBREG)
          reg = SUBREG_REG (reg);
            
        if (REG_P (reg) && (regno = REGNO (reg)) >= FIRST_PSEUDO_REGISTER)
          {
            bool ok_p = in_class_p (reg, goal_alt[i], &new_class);

            if (new_class != NO_REGS && get_reg_class (regno) != new_class)
              {
                lra_assert (ok_p);
                change_class (regno, new_class, "      Change", true);
              }
          }
      }
    else
      {
        const char *constraint;
        char c;
        rtx op = *curr_id->operand_loc[i];
        rtx subreg = NULL_RTX;
        enum machine_mode mode = curr_operand_mode[i];
        
        if (GET_CODE (op) == SUBREG)
          {
            subreg = op;
            op = SUBREG_REG (op);
            mode = GET_MODE (op);
          }
        
        if (CONST_POOL_OK_P (mode, op)
            && ((targetm.preferred_reload_class
                 (op, (enum reg_class) goal_alt[i]) == NO_REGS)
                || no_input_reloads_p))
          {
            rtx tem = force_const_mem (mode, op);
            
            change_p = true;
            if (subreg != NULL_RTX)
              tem = gen_rtx_SUBREG (mode, tem, SUBREG_BYTE (subreg));
            
            *curr_id->operand_loc[i] = tem;
            lra_update_dup (curr_id, i);
            process_address (i, &before, &after);
            
            /* If the alternative accepts constant pool refs directly
               there will be no reload needed at all.  */
            if (subreg != NULL_RTX)
              continue;
            /* Skip alternatives before the one requested.  */
            constraint = (curr_static_id->operand_alternative
                          [goal_alt_number * n_operands + i].constraint);
            for (;
                 (c = *constraint) && c != ',' && c != '#';
                 constraint += CONSTRAINT_LEN (c, constraint))
              {
                if (c == TARGET_MEM_CONSTRAINT || c == 'o')
                  break;
#ifdef EXTRA_CONSTRAINT_STR
                if (EXTRA_MEMORY_CONSTRAINT (c, constraint)
                    && EXTRA_CONSTRAINT_STR (tem, c, constraint))
                  break;
#endif
              }
            if (c == '\0' || c == ',' || c == '#')
              continue;
            
            goal_alt_win[i] = true;
          }
      }
  
  for (i = 0; i < n_operands; i++)
    {
      rtx old, new_reg;
      rtx op = *curr_id->operand_loc[i];

      if (goal_alt_win[i])
        {
          if (goal_alt[i] == NO_REGS
              && REG_P (op)
              /* When we assign NO_REGS it means that we will not
                 assign a hard register to the scratch pseudo by
                 assigment pass and the scratch pseudo will be
                 spilled.  Spilled scratch pseudos are transformed
                 back to scratches at the LRA end.  */
              && lra_former_scratch_operand_p (curr_insn, i))
            change_class (REGNO (op), NO_REGS, "      Change", true);
          continue;
        }
      
      /* Operands that match previous ones have already been handled.  */
      if (goal_alt_matches[i] >= 0)
        continue;

      /* We should not have an operand with a non-offsettable address
         appearing where an offsettable address will do.  It also may
         be a case when the address should be special in other words
         not a general one (e.g. it needs no index reg).  */
      if (goal_alt_matched[i][0] == -1 && goal_alt_offmemok[i] && MEM_P (op))
        {
          enum reg_class rclass;
          rtx *loc = &XEXP (op, 0);
          enum rtx_code code = GET_CODE (*loc);

          push_to_sequence (before);
          rclass = base_reg_class (GET_MODE (op), MEM_ADDR_SPACE (op),
                                   MEM, SCRATCH);
          if (GET_RTX_CLASS (code) == RTX_AUTOINC)
            new_reg = emit_inc (rclass, *loc, *loc,
                                /* This value does not matter for MODIFY.  */
                                GET_MODE_SIZE (GET_MODE (op)));
          else if (get_reload_reg (OP_IN, Pmode, *loc, rclass,
                                   "offsetable address", &new_reg))
            lra_emit_move (new_reg, *loc);
          before = get_insns ();
          end_sequence ();
          *loc = new_reg;
          lra_update_dup (curr_id, i);
        }
      else if (goal_alt_matched[i][0] == -1)
        {
          enum machine_mode mode;
          rtx reg, *loc;
          int hard_regno, byte;
          enum op_type type = curr_static_id->operand[i].type;

          loc = curr_id->operand_loc[i];
          mode = curr_operand_mode[i];
          if (GET_CODE (*loc) == SUBREG)
            {
              reg = SUBREG_REG (*loc);
              byte = SUBREG_BYTE (*loc);
              if (REG_P (reg)
                  /* Strict_low_part requires reload the register not
                     the sub-register.  */
                  && (curr_static_id->operand[i].strict_low
                      || (GET_MODE_SIZE (mode)
                          <= GET_MODE_SIZE (GET_MODE (reg))
                          && (hard_regno
                              = get_try_hard_regno (REGNO (reg))) >= 0
                          && (simplify_subreg_regno
                              (hard_regno,
                               GET_MODE (reg), byte, mode) < 0)
                          && (goal_alt[i] == NO_REGS
                              || (simplify_subreg_regno
                                  (ira_class_hard_regs[goal_alt[i]][0],
                                   GET_MODE (reg), byte, mode) >= 0)))))
                {
                  loc = &SUBREG_REG (*loc);
                  mode = GET_MODE (*loc);
                }
            }
          old = *loc;
          if (get_reload_reg (type, mode, old, goal_alt[i], "", &new_reg)
              && type != OP_OUT)
            {
              push_to_sequence (before);
              lra_emit_move (new_reg, old);
              before = get_insns ();
              end_sequence ();
            }
          *loc = new_reg;
          if (type != OP_IN
              && find_reg_note (curr_insn, REG_UNUSED, old) == NULL_RTX)
            {
              start_sequence ();
              lra_emit_move (type == OP_INOUT ? copy_rtx (old) : old, new_reg);
              emit_insn (after);
              after = get_insns ();
              end_sequence ();
              *loc = new_reg;
            }
          for (j = 0; j < goal_alt_dont_inherit_ops_num; j++)
            if (goal_alt_dont_inherit_ops[j] == i)
              {
                lra_set_regno_unique_value (REGNO (new_reg));
                break;
              }
          lra_update_dup (curr_id, i);
        }
      else if (curr_static_id->operand[i].type == OP_IN
               && (curr_static_id->operand[goal_alt_matched[i][0]].type
                   == OP_OUT))
        {
          signed char arr[2];

          arr[0] = i;
          arr[1] = -1;
          match_reload (goal_alt_matched[i][0], arr,
                        goal_alt[i], &before, &after);
        }
      else if (curr_static_id->operand[i].type == OP_OUT
               && (curr_static_id->operand[goal_alt_matched[i][0]].type
                   == OP_IN))
        match_reload (i, goal_alt_matched[i], goal_alt[i], &before, &after);
      else
        /* We must generate code in any case when function
           process_alt_operands decides that it is possible.  */
        gcc_unreachable ();
    }
  if (before != NULL_RTX || after != NULL_RTX
      || max_regno_before != max_reg_num ())
    change_p = true;
  if (change_p)
    {
      lra_update_operator_dups (curr_id);
      /* Something changes -- process the insn.  */
      lra_update_insn_regno_info (curr_insn);
    }
  lra_process_new_insns (curr_insn, before, after, "Inserting insn reload");
  return change_p;
}

/* Return true if X is in LIST.  */
static bool
in_list_p (rtx x, rtx list)
{
  for (; list != NULL_RTX; list = XEXP (list, 1))
    if (XEXP (list, 0) == x)
      return true;
  return false;
}

/* Return true if X contains an allocatable hard register (if
   HARD_REG_P) or a (spilled if SPILLED_P) pseudo.  */
static bool
contains_reg_p (rtx x, bool hard_reg_p, bool spilled_p)
{
  int i, j;
  const char *fmt;
  enum rtx_code code;

  code = GET_CODE (x);
  if (REG_P (x))
    {
      int regno = REGNO (x);
      HARD_REG_SET alloc_regs;

      if (hard_reg_p)
        {
          if (regno >= FIRST_PSEUDO_REGISTER)
            regno = lra_get_regno_hard_regno (regno);
          if (regno < 0)
            return false;
          COMPL_HARD_REG_SET (alloc_regs, lra_no_alloc_regs);
          return overlaps_hard_reg_set_p (alloc_regs, GET_MODE (x), regno);
        }
      else
        {
          if (regno < FIRST_PSEUDO_REGISTER)
            return false;
          if (! spilled_p)
            return true;
          return lra_get_regno_hard_regno (regno) < 0;
        }
    }
  fmt = GET_RTX_FORMAT (code);
  for (i = GET_RTX_LENGTH (code) - 1; i >= 0; i--)
    {
      if (fmt[i] == 'e')
        {
          if (contains_reg_p (XEXP (x, i), hard_reg_p, spilled_p))
            return true;
        }
      else if (fmt[i] == 'E')
        {
          for (j = XVECLEN (x, i) - 1; j >= 0; j--)
            if (contains_reg_p (XVECEXP (x, i, j), hard_reg_p, spilled_p))
              return true;
        }
    }
  return false;
}

/* Process all regs in debug location *LOC and change them on
   equivalent substitution.  Return true if any change was done.  */
static bool
debug_loc_equivalence_change_p (rtx *loc)
{
  rtx subst, reg, x = *loc;
  bool result = false;
  enum rtx_code code = GET_CODE (x);
  const char *fmt;
  int i, j;

  if (code == SUBREG)
    {
      reg = SUBREG_REG (x);
      if ((subst = get_equiv_substitution (reg)) != reg
          && GET_MODE (subst) == VOIDmode)
        {
          /* We cannot reload debug location.  Simplify subreg here
             while we know the inner mode.  */
          *loc = simplify_gen_subreg (GET_MODE (x), subst,
                                      GET_MODE (reg), SUBREG_BYTE (x));
          return true;
        }
    }
  if (code == REG && (subst = get_equiv_substitution (x)) != x)
    {
      *loc = subst;
      return true;
    }

  /* Scan all the operand sub-expressions.  */
  fmt = GET_RTX_FORMAT (code);
  for (i = GET_RTX_LENGTH (code) - 1; i >= 0; i--)
    {
      if (fmt[i] == 'e')
        result = debug_loc_equivalence_change_p (&XEXP (x, i)) || result;
      else if (fmt[i] == 'E')
        for (j = XVECLEN (x, i) - 1; j >= 0; j--)
          result
            = debug_loc_equivalence_change_p (&XVECEXP (x, i, j)) || result;
    }
  return result;
}

/* Maximum allowed number of constraint pass iterations after the last
   spill pass.  It is for preventing LRA cycling in a bug case.  */
#define MAX_CONSTRAINT_ITERATION_NUMBER 15

/* Maximum number of generated reload insns per an insn.  It is for
   preventing this pass cycling in a bug case.  */
#define MAX_RELOAD_INSNS_NUMBER LRA_MAX_INSN_RELOADS

/* The current iteration number of this LRA pass.  */
int lra_constraint_iter;

/* The current iteration number of this LRA pass after the last spill
   pass.  */
int lra_constraint_iter_after_spill;

/* True if we substituted equiv which needs checking register
   allocation correctness because the equivalent value contains
   allocatable hard registers or when we restore multi-register
   pseudo.  */
bool lra_risky_transformations_p;

/* Return true if REGNO is referenced in more than one block.  */
static bool
multi_block_pseudo_p (int regno)
{
  basic_block bb = NULL;
  unsigned int uid;
  bitmap_iterator bi;
  
  if (regno < FIRST_PSEUDO_REGISTER)
    return false;
  
    EXECUTE_IF_SET_IN_BITMAP (&lra_reg_info[regno].insn_bitmap, 0, uid, bi)
      if (bb == NULL)
        bb = BLOCK_FOR_INSN (lra_insn_recog_data[uid]->insn);
      else if (BLOCK_FOR_INSN (lra_insn_recog_data[uid]->insn) != bb)
        return true;
    return false;
}

/* Return true if X contains a pseudo dying in INSN.  */
static bool
dead_pseudo_p (rtx x, rtx insn)
{
  int i, j;
  const char *fmt;
  enum rtx_code code;

  if (REG_P (x))
    return (insn != NULL_RTX
            && find_regno_note (insn, REG_DEAD, REGNO (x)) != NULL_RTX);
  code = GET_CODE (x);
  fmt = GET_RTX_FORMAT (code);
  for (i = GET_RTX_LENGTH (code) - 1; i >= 0; i--)
    {
      if (fmt[i] == 'e')
        {
          if (dead_pseudo_p (XEXP (x, i), insn))
            return true;
        }
      else if (fmt[i] == 'E')
        {
          for (j = XVECLEN (x, i) - 1; j >= 0; j--)
            if (dead_pseudo_p (XVECEXP (x, i, j), insn))
              return true;
        }
    }
  return false;
}

/* Return true if INSN contains a dying pseudo in INSN right hand
   side.  */
static bool
insn_rhs_dead_pseudo_p (rtx insn)
{
  rtx set = single_set (insn);

  gcc_assert (set != NULL);
  return dead_pseudo_p (SET_SRC (set), insn);
}

/* Return true if any init insn of REGNO contains a dying pseudo in
   insn right hand side.  */
static bool
init_insn_rhs_dead_pseudo_p (int regno)
{
  rtx insns = ira_reg_equiv[regno].init_insns;

  if (insns == NULL)
    return false;
  if (INSN_P (insns))
    return insn_rhs_dead_pseudo_p (insns);
  for (; insns != NULL_RTX; insns = XEXP (insns, 1))
    if (insn_rhs_dead_pseudo_p (XEXP (insns, 0)))
      return true;
  return false;
}

/* Entry function of LRA constraint pass.  Return true if the
   constraint pass did change the code.  */
bool
lra_constraints (bool first_p)
{
  bool changed_p;
  int i, hard_regno, new_insns_num;
  unsigned int min_len, new_min_len;
  rtx set, x, dest_reg;
  basic_block last_bb;

  lra_constraint_iter++;
  if (lra_dump_file != NULL)
    fprintf (lra_dump_file, "\n********** Local #%d: **********\n\n",
             lra_constraint_iter);
  lra_constraint_iter_after_spill++;
  if (lra_constraint_iter_after_spill > MAX_CONSTRAINT_ITERATION_NUMBER)
    internal_error
      ("Maximum number of LRA constraint passes is achieved (%d)\n",
       MAX_CONSTRAINT_ITERATION_NUMBER);
  changed_p = false;
  lra_risky_transformations_p = false;
  new_insn_uid_start = get_max_uid ();
  new_regno_start = first_p ? lra_constraint_new_regno_start : max_reg_num ();
  for (i = FIRST_PSEUDO_REGISTER; i < new_regno_start; i++)
    if (lra_reg_info[i].nrefs != 0)
      {
        ira_reg_equiv[i].profitable_p = true;
        if ((hard_regno = lra_get_regno_hard_regno (i)) >= 0)
          {
            int j, nregs = hard_regno_nregs[hard_regno][PSEUDO_REGNO_MODE (i)];
            
            for (j = 0; j < nregs; j++)
              df_set_regs_ever_live (hard_regno + j, true);
          }
        else if ((x = get_equiv_substitution (regno_reg_rtx[i])) != NULL_RTX)
          {
            bool pseudo_p = contains_reg_p (x, false, false);
            rtx set, insn;

            /* We don't use DF for compilation speed sake.  So it is
               problematic to update live info when we use an
               equivalence containing pseudos in more than one BB.  */
            if ((pseudo_p && multi_block_pseudo_p (i))
                /* If it is not a reverse equivalence, we check that a
                   pseudo in rhs of the init insn is not dying in the
                   insn.  Otherwise, the live info at the beginning of
                   the corresponding BB might be wrong after we
                   removed the insn.  When the equiv can be a
                   constant, the right hand side of the init insn can
                   be a pseudo.  */
                || (! ((insn = ira_reg_equiv[i].init_insns) != NULL_RTX
                       && INSN_P (insn)
                       && (set = single_set (insn)) != NULL_RTX
                       && REG_P (SET_DEST (set))
                       && (int) REGNO (SET_DEST (set)) == i)
                    && init_insn_rhs_dead_pseudo_p (i)))
              ira_reg_equiv[i].defined_p = false;
            else if (! first_p && pseudo_p)
              /* After RTL transformation, we can not guarantee that
                 pseudo in the substitution was not reloaded which
                 might make equivalence invalid.  For example, in
                 reverse equiv of p0

                 p0 <- ...
                 ...
                 equiv_mem <- p0

                 the memory address register was reloaded before the
                 2nd insn.  */
              ira_reg_equiv[i].defined_p = false;
            if (contains_reg_p (x, false, true))
              ira_reg_equiv[i].profitable_p = false;
          }
      }
  lra_eliminate (false);
  min_len = lra_insn_stack_length ();
  new_insns_num = 0;
  last_bb = NULL;
  changed_p = false;
  while ((new_min_len = lra_insn_stack_length ()) != 0)
    {
      curr_insn = lra_pop_insn ();
      --new_min_len;
      curr_bb = BLOCK_FOR_INSN (curr_insn); 
      if (curr_bb != last_bb)
        {
          last_bb = curr_bb;
          bb_reload_num = lra_curr_reload_num;
        }
      if (min_len > new_min_len)
        {
          min_len = new_min_len;
          new_insns_num = 0;
        }
      if (new_insns_num > MAX_RELOAD_INSNS_NUMBER)
        internal_error
          ("Max. number of generated reload insns per insn is achieved (%d)\n",
           MAX_RELOAD_INSNS_NUMBER);
      new_insns_num++;
      if (DEBUG_INSN_P (curr_insn))
        {
          /* We need to check equivalence in debug insn and change
             pseudo to the equivalent value if necessary.  */
          curr_id = lra_get_insn_recog_data (curr_insn);
          if (debug_loc_equivalence_change_p (curr_id->operand_loc[0]))
            changed_p = true;
        }
      else if (INSN_P (curr_insn))
        {
          if ((set = single_set (curr_insn)) != NULL_RTX)
            {
              dest_reg = SET_DEST (set);
              /* The equivalence pseudo could be set up as SUBREG in a
                 case when it is a call restore insn in a mode
                 different from the pseudo mode.  */
              if (GET_CODE (dest_reg) == SUBREG)
                dest_reg = SUBREG_REG (dest_reg);
              if ((REG_P (dest_reg)
                   && (x = get_equiv_substitution (dest_reg)) != dest_reg
                   /* Remove insns which set up a pseudo whose value
                      can not be changed.  Such insns might be not in
                      init_insns because we don't update equiv data
                      during insn transformations.
                          
                      As an example, let suppose that a pseudo got
                      hard register and on the 1st pass was not
                      changed to equivalent constant.  We generate an
                      additional insn setting up the pseudo because of
                      secondary memory movement.  Then the pseudo is
                      spilled and we use the equiv constant.  In this
                      case we should remove the additional insn and
                      this insn is not init_insns list.  */
                   && (! MEM_P (x) || MEM_READONLY_P (x)
                       || in_list_p (curr_insn,
                                     ira_reg_equiv
                                     [REGNO (dest_reg)].init_insns)))
                  || (((x = get_equiv_substitution (SET_SRC (set)))
                       != SET_SRC (set))
                      && in_list_p (curr_insn,
                                    ira_reg_equiv
                                    [REGNO (SET_SRC (set))].init_insns)))
                {
                  /* This is equiv init insn of pseudo which did not get a
                     hard register -- remove the insn.  */
                  if (lra_dump_file != NULL)
                    {
                      fprintf (lra_dump_file,
                               "      Removing equiv init insn %i (freq=%d)\n",
                               INSN_UID (curr_insn),
                               BLOCK_FOR_INSN (curr_insn)->frequency);
                      debug_rtl_slim (lra_dump_file,
                                      curr_insn, curr_insn, -1, 0);
                    }
                  if (contains_reg_p (x, true, false))
                    lra_risky_transformations_p = true;
                  lra_set_insn_deleted (curr_insn);
                  continue;
                }
            }
          curr_id = lra_get_insn_recog_data (curr_insn);
          curr_static_id = curr_id->insn_static_data;
          init_curr_insn_input_reloads ();
          init_curr_operand_mode ();
          if (curr_insn_transform ())
            changed_p = true;
        }
    }
  /* If we used a new hard regno, changed_p should be true because the
     hard reg is assigned to a new pseudo.  */
#ifdef ENABLE_CHECKING
  if (! changed_p)
    {
      for (i = FIRST_PSEUDO_REGISTER; i < new_regno_start; i++)
        if (lra_reg_info[i].nrefs != 0
            && (hard_regno = lra_get_regno_hard_regno (i)) >= 0)
          {
            int j, nregs = hard_regno_nregs[hard_regno][PSEUDO_REGNO_MODE (i)];
            
            for (j = 0; j < nregs; j++)
              lra_assert (df_regs_ever_live_p (hard_regno + j));
          }
    }
#endif
  return changed_p;
}

/* Initiate the LRA constraint pass.  It is done once per
   function.  */
void
lra_constraints_init (void)
{
}

/* Finalize the LRA constraint pass.  It is done once per
   function.  */
void
lra_constraints_finish (void)
{
}

\f

/* This page contains code to do inheritance/split
   transformations.  */

/* Number of reloads passed so far in current EBB.  */
static int reloads_num;

/* Number of calls passed so far in current EBB.  */
static int calls_num;

/* Current reload pseudo check for validity of elements in
   USAGE_INSNS.  */
static int curr_usage_insns_check;

/* Info about last usage of registers in EBB to do inheritance/split
   transformation.  Inheritance transformation is done from a spilled
   pseudo and split transformations from a hard register or a pseudo
   assigned to a hard register.  */
struct usage_insns
{
  /* If the value is equal to CURR_USAGE_INSNS_CHECK, then the member
     value INSNS is valid.  The insns is chain of optional debug insns
     and a finishing non-debug insn using the corresponding reg.  */
  int check;
  /* Value of global reloads_num at the last insn in INSNS.  */
  int reloads_num;
  /* Value of global reloads_nums at the last insn in INSNS.  */
  int calls_num;
  /* It can be true only for splitting.  And it means that the restore
     insn should be put after insn given by the following member.  */
  bool after_p;
  /* Next insns in the current EBB which use the original reg and the
     original reg value is not changed between the current insn and
     the next insns.  In order words, e.g. for inheritance, if we need
     to use the original reg value again in the next insns we can try
     to use the value in a hard register from a reload insn of the
     current insn.  */
  rtx insns;
};

/* Map: regno -> corresponding pseudo usage insns.  */
static struct usage_insns *usage_insns;

static void
setup_next_usage_insn (int regno, rtx insn, int reloads_num, bool after_p)
{
  usage_insns[regno].check = curr_usage_insns_check;
  usage_insns[regno].insns = insn;
  usage_insns[regno].reloads_num = reloads_num;
  usage_insns[regno].calls_num = calls_num;
  usage_insns[regno].after_p = after_p;
}

/* The function is used to form list REGNO usages which consists of
   optional debug insns finished by a non-debug insn using REGNO.
   RELOADS_NUM is current number of reload insns processed so far.  */
static void
add_next_usage_insn (int regno, rtx insn, int reloads_num)
{
  rtx next_usage_insns;
  
  if (usage_insns[regno].check == curr_usage_insns_check
      && (next_usage_insns = usage_insns[regno].insns) != NULL_RTX
      && DEBUG_INSN_P (insn))
    {
      /* Check that we did not add the debug insn yet.  */
      if (next_usage_insns != insn
          && (GET_CODE (next_usage_insns) != INSN_LIST
              || XEXP (next_usage_insns, 0) != insn))
        usage_insns[regno].insns = gen_rtx_INSN_LIST (VOIDmode, insn,
                                                      next_usage_insns);
    }
  else if (NONDEBUG_INSN_P (insn))
    setup_next_usage_insn (regno, insn, reloads_num, false);
  else
    usage_insns[regno].check = 0;
}
  
/* Replace all references to register OLD_REGNO in *LOC with pseudo
   register NEW_REG.  Return true if any change was made.  */
static bool
substitute_pseudo (rtx *loc, int old_regno, rtx new_reg)
{
  rtx x = *loc;
  bool result = false;
  enum rtx_code code;
  const char *fmt;
  int i, j;

  if (x == NULL_RTX)
    return false;

  code = GET_CODE (x);
  if (code == REG && (int) REGNO (x) == old_regno)
    {
      enum machine_mode mode = GET_MODE (*loc);
      enum machine_mode inner_mode = GET_MODE (new_reg);

      if (mode != inner_mode)
        {
          if (GET_MODE_SIZE (mode) >= GET_MODE_SIZE (inner_mode)
              || ! SCALAR_INT_MODE_P (inner_mode))
            new_reg = gen_rtx_SUBREG (mode, new_reg, 0);
          else
            new_reg = gen_lowpart_SUBREG (mode, new_reg);
        }
      *loc = new_reg;
      return true;
    }

  /* Scan all the operand sub-expressions.  */
  fmt = GET_RTX_FORMAT (code);
  for (i = GET_RTX_LENGTH (code) - 1; i >= 0; i--)
    {
      if (fmt[i] == 'e')
        {
          if (substitute_pseudo (&XEXP (x, i), old_regno, new_reg))
            result = true;
        }
      else if (fmt[i] == 'E')
        {
          for (j = XVECLEN (x, i) - 1; j >= 0; j--)
            if (substitute_pseudo (&XVECEXP (x, i, j), old_regno, new_reg))
              result = true;
        }
    }
  return result;
}

/* Registers involved in inheritance/split in the current EBB
   (inheritance/split pseudos and original registers).  */
static bitmap_head check_only_regs;

/* Do inheritance transformations for insn INSN, which defines (if
   DEF_P) or uses ORIGINAL_REGNO.  NEXT_USAGE_INSNS specifies which
   instruction in the EBB next uses ORIGINAL_REGNO; it has the same
   form as the "insns" field of usage_insns.  Return true if we
   succeed in such transformation.

   The transformations look like:

     p <- ...             i <- ...
     ...                  p <- i    (new insn)
     ...             =>
     <- ... p ...         <- ... i ...
   or
     ...                  i <- p    (new insn)
     <- ... p ...         <- ... i ...
     ...             =>
     <- ... p ...         <- ... i ...
   where p is a spilled original pseudo and i is a new inheritance pseudo.
   
   
   The inheritance pseudo has the smallest class of two classes CL and
   class of ORIGINAL REGNO.  */
static bool
inherit_reload_reg (bool def_p, int original_regno,
                    enum reg_class cl, rtx insn, rtx next_usage_insns)
{
  enum reg_class rclass = lra_get_allocno_class (original_regno);
  rtx original_reg = regno_reg_rtx[original_regno];
  rtx new_reg, new_insns, usage_insn;

  lra_assert (! usage_insns[original_regno].after_p);
  if (lra_dump_file != NULL)
    fprintf (lra_dump_file,
             "    <<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<\n");
  if (! ira_reg_classes_intersect_p[cl][rclass])
    {
      if (lra_dump_file != NULL)
        {
          fprintf (lra_dump_file,
                   "    Rejecting inheritance for %d "
                   "because of disjoint classes %s and %s\n",
                   original_regno, reg_class_names[cl],
                   reg_class_names[rclass]);
          fprintf (lra_dump_file,
                   "    >>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>\n");
        }
      return false;
    }
  if ((ira_class_subset_p[cl][rclass] && cl != rclass)
      /* We don't use a subset of two classes because it can be
         NO_REGS.  This transformation is still profitable in most
         cases even if the classes are not intersected as register
         move is probably cheaper than a memory load.  */
      || ira_class_hard_regs_num[cl] < ira_class_hard_regs_num[rclass])
    {
      if (lra_dump_file != NULL)
        fprintf (lra_dump_file, "    Use smallest class of %s and %s\n",
                 reg_class_names[cl], reg_class_names[rclass]);
      
      rclass = cl;
    }
  new_reg = lra_create_new_reg (GET_MODE (original_reg), original_reg,
                                rclass, "inheritance");
  start_sequence ();
  if (def_p)
    emit_move_insn (original_reg, new_reg);
  else
    emit_move_insn (new_reg, original_reg);
  new_insns = get_insns ();
  end_sequence ();
  if (NEXT_INSN (new_insns) != NULL_RTX)
    {
      if (lra_dump_file != NULL)
        {
          fprintf (lra_dump_file,
                   "    Rejecting inheritance %d->%d "
                   "as it results in 2 or more insns:\n",
                   original_regno, REGNO (new_reg));
          debug_rtl_slim (lra_dump_file, new_insns, NULL_RTX, -1, 0);
          fprintf (lra_dump_file,
                   "    >>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>\n");
        }
      return false;
    }
  substitute_pseudo (&insn, original_regno, new_reg);
  lra_update_insn_regno_info (insn);
  if (! def_p)
    /* We now have a new usage insn for original regno.  */
    setup_next_usage_insn (original_regno, new_insns, reloads_num, false);
  if (lra_dump_file != NULL)
    fprintf (lra_dump_file, "    Original reg change %d->%d (bb%d):\n",
             original_regno, REGNO (new_reg), BLOCK_FOR_INSN (insn)->index);
  lra_reg_info[REGNO (new_reg)].restore_regno = original_regno;
  bitmap_set_bit (&check_only_regs, REGNO (new_reg));
  bitmap_set_bit (&check_only_regs, original_regno);
  bitmap_set_bit (&lra_inheritance_pseudos, REGNO (new_reg));
  if (def_p)
    lra_process_new_insns (insn, NULL_RTX, new_insns,
                           "Add original<-inheritance");
  else
    lra_process_new_insns (insn, new_insns, NULL_RTX,
                           "Add inheritance<-original");
  while (next_usage_insns != NULL_RTX)
    {
      if (GET_CODE (next_usage_insns) != INSN_LIST)
        {
          usage_insn = next_usage_insns;
          lra_assert (NONDEBUG_INSN_P (usage_insn));
          next_usage_insns = NULL;
        }
      else
        {
          usage_insn = XEXP (next_usage_insns, 0);
          lra_assert (DEBUG_INSN_P (usage_insn));
          next_usage_insns = XEXP (next_usage_insns, 1);
        }
      substitute_pseudo (&usage_insn, original_regno, new_reg);
      lra_update_insn_regno_info (usage_insn);
      if (lra_dump_file != NULL)
        {
          fprintf (lra_dump_file,
                   "    Inheritance reuse change %d->%d (bb%d):\n",
                   original_regno, REGNO (new_reg),
                   BLOCK_FOR_INSN (usage_insn)->index);
          debug_rtl_slim (lra_dump_file, usage_insn, usage_insn,
                          -1, 0);
        }
    }
  if (lra_dump_file != NULL)
    fprintf (lra_dump_file,
             "    >>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>\n");
  return true;
}

/* Return true if we need a caller save/restore for pseudo REGNO which
   was assigned to a hard register.  */
static inline bool
need_for_call_save_p (int regno)
{
  lra_assert (regno >= FIRST_PSEUDO_REGISTER && reg_renumber[regno] >= 0);
  return (usage_insns[regno].calls_num < calls_num
          && (overlaps_hard_reg_set_p
              (call_used_reg_set,
               PSEUDO_REGNO_MODE (regno), reg_renumber[regno])));
}

/* Global registers occuring in the current EBB.  */
static bitmap_head ebb_global_regs;

/* Return true if we need a split for hard register REGNO or pseudo
   REGNO which was assigned to a hard register.
   POTENTIAL_RELOAD_HARD_REGS contains hard registers which might be
   used for reloads since the EBB end.  It is an approximation of the
   used hard registers in the split range.  The exact value would
   require expensive calculations.  If we were aggressive with
   splitting because of the approximation, the split pseudo will save
   the same hard register assignment and will be removed in the undo
   pass.  We still need the approximation because too aggressive
   splitting would result in too inaccurate cost calculation in the
   assignment pass because of too many generated moves which will be
   probably removed in the undo pass.  */
static inline bool
need_for_split_p (HARD_REG_SET potential_reload_hard_regs, int regno)
{
  int hard_regno = regno < FIRST_PSEUDO_REGISTER ? regno : reg_renumber[regno];

  lra_assert (hard_regno >= 0);
  return ((TEST_HARD_REG_BIT (potential_reload_hard_regs, hard_regno)
           /* Don't split eliminable hard registers, otherwise we can
              split hard registers like hard frame pointer, which
              lives on BB start/end according to DF-infrastructure,
              when there is a pseudo assigned to the register and
              living in the same BB.  */
           && (regno >= FIRST_PSEUDO_REGISTER
               || ! TEST_HARD_REG_BIT (eliminable_regset, hard_regno))
           && ! TEST_HARD_REG_BIT (lra_no_alloc_regs, hard_regno)
           /* We need at least 2 reloads to make pseudo splitting
              profitable.  We should provide hard regno splitting in
              any case to solve 1st insn scheduling problem when
              moving hard register definition up might result in
              impossibility to find hard register for reload pseudo of
              small register class.  */
           && (usage_insns[regno].reloads_num
               + (regno < FIRST_PSEUDO_REGISTER ? 0 : 2) < reloads_num)
           && (regno < FIRST_PSEUDO_REGISTER
               /* For short living pseudos, spilling + inheritance can
                  be considered a substitution for splitting.
                  Therefore we do not splitting for local pseudos.  It
                  decreases also aggressiveness of splitting.  The
                  minimal number of references is chosen taking into
                  account that for 2 references splitting has no sense
                  as we can just spill the pseudo.  */
               || (regno >= FIRST_PSEUDO_REGISTER
                   && lra_reg_info[regno].nrefs > 3
                   && bitmap_bit_p (&ebb_global_regs, regno))))
          || (regno >= FIRST_PSEUDO_REGISTER && need_for_call_save_p (regno)));
}

/* Return class for the split pseudo created from original pseudo with
   ALLOCNO_CLASS and MODE which got a hard register HARD_REGNO.  We
   choose subclass of ALLOCNO_CLASS which contains HARD_REGNO and
   results in no secondary memory movements.  */
static enum reg_class
choose_split_class (enum reg_class allocno_class,
                    int hard_regno ATTRIBUTE_UNUSED,
                    enum machine_mode mode ATTRIBUTE_UNUSED)
{
#ifndef SECONDARY_MEMORY_NEEDED
  return allocno_class;
#else
  int i;
  enum reg_class cl, best_cl = NO_REGS;
  enum reg_class hard_reg_class = REGNO_REG_CLASS (hard_regno);
  
  if (! SECONDARY_MEMORY_NEEDED (allocno_class, allocno_class, mode)
      && TEST_HARD_REG_BIT (reg_class_contents[allocno_class], hard_regno))
    return allocno_class;
  for (i = 0;
       (cl = reg_class_subclasses[allocno_class][i]) != LIM_REG_CLASSES;
       i++)
    if (! SECONDARY_MEMORY_NEEDED (cl, hard_reg_class, mode)
        && ! SECONDARY_MEMORY_NEEDED (hard_reg_class, cl, mode)
        && TEST_HARD_REG_BIT (reg_class_contents[cl], hard_regno)
        && (best_cl == NO_REGS
            || ira_class_hard_regs_num[best_cl] < ira_class_hard_regs_num[cl]))
      best_cl = cl;
  return best_cl;
#endif
}

/* Do split transformations for insn INSN, which defines or uses
   ORIGINAL_REGNO.  NEXT_USAGE_INSNS specifies which instruction in
   the EBB next uses ORIGINAL_REGNO; it has the same form as the
   "insns" field of usage_insns.

   The transformations look like:

     p <- ...             p <- ...
     ...                  s <- p    (new insn -- save)
     ...             =>
     ...                  p <- s    (new insn -- restore)
     <- ... p ...         <- ... p ...
   or
     <- ... p ...         <- ... p ...
     ...                  s <- p    (new insn -- save)
     ...             =>
     ...                  p <- s    (new insn -- restore)
     <- ... p ...         <- ... p ...

   where p is an original pseudo got a hard register or a hard
   register and s is a new split pseudo.  The save is put before INSN
   if BEFORE_P is true.  Return true if we succeed in such
   transformation.  */
static bool
split_reg (bool before_p, int original_regno, rtx insn, rtx next_usage_insns)
{
  enum reg_class rclass;
  rtx original_reg;
  int hard_regno;
  rtx new_reg, save, restore, usage_insn;
  bool after_p;
  bool call_save_p;

  if (original_regno < FIRST_PSEUDO_REGISTER)
    {
      rclass = ira_allocno_class_translate[REGNO_REG_CLASS (original_regno)];
      hard_regno = original_regno;
      call_save_p = false;
    }
  else
    {
      hard_regno = reg_renumber[original_regno];
      rclass = lra_get_allocno_class (original_regno);
      original_reg = regno_reg_rtx[original_regno];
      call_save_p = need_for_call_save_p (original_regno);
    }
  original_reg = regno_reg_rtx[original_regno];
  lra_assert (hard_regno >= 0);
  if (lra_dump_file != NULL)
    fprintf (lra_dump_file,
             "    ((((((((((((((((((((((((((((((((((((((((((((((((\n");
  if (call_save_p)
    {
      enum machine_mode sec_mode;
      
#ifdef SECONDARY_MEMORY_NEEDED_MODE
      sec_mode = SECONDARY_MEMORY_NEEDED_MODE (GET_MODE (original_reg));
#else
      sec_mode = GET_MODE (original_reg);
#endif
      new_reg = lra_create_new_reg (sec_mode, NULL_RTX,
                                    NO_REGS, "save");
    }
  else
    {
      rclass = choose_split_class (rclass, hard_regno,
                                   GET_MODE (original_reg));
      if (rclass == NO_REGS)
        {
          if (lra_dump_file != NULL)
            {
              fprintf (lra_dump_file,
                       "    Rejecting split of %d(%s): "
                       "no good reg class for %d(%s)\n",
                       original_regno,
                       reg_class_names[lra_get_allocno_class (original_regno)],
                       hard_regno,
                       reg_class_names[REGNO_REG_CLASS (hard_regno)]);
              fprintf
                (lra_dump_file,
                 "    ))))))))))))))))))))))))))))))))))))))))))))))))\n");
            }
          return false;
        }
      new_reg = lra_create_new_reg (GET_MODE (original_reg), original_reg,
                                    rclass, "split");
      reg_renumber[REGNO (new_reg)] = hard_regno;
    }
  save = emit_spill_move (true, new_reg, original_reg);
  if (NEXT_INSN (save) != NULL_RTX)
    {
      lra_assert (! call_save_p);
      if (lra_dump_file != NULL)
        {
          fprintf
            (lra_dump_file,
             "    Rejecting split %d->%d resulting in > 2 %s save insns:\n",
             original_regno, REGNO (new_reg), call_save_p ? "call" : "");
          debug_rtl_slim (lra_dump_file, save, NULL_RTX, -1, 0);
          fprintf (lra_dump_file,
                   "    ))))))))))))))))))))))))))))))))))))))))))))))))\n");
        }
      return false;
    }
  restore = emit_spill_move (false, new_reg, original_reg);
  if (NEXT_INSN (restore) != NULL_RTX)
    {
      lra_assert (! call_save_p);
      if (lra_dump_file != NULL)
        {
          fprintf (lra_dump_file,
                   "    Rejecting split %d->%d "
                   "resulting in > 2 %s restore insns:\n",
                   original_regno, REGNO (new_reg), call_save_p ? "call" : "");
          debug_rtl_slim (lra_dump_file, restore, NULL_RTX, -1, 0);
          fprintf (lra_dump_file,
                   "    ))))))))))))))))))))))))))))))))))))))))))))))))\n");
        }
      return false;
    }
  after_p = usage_insns[original_regno].after_p;
  lra_reg_info[REGNO (new_reg)].restore_regno = original_regno;
  bitmap_set_bit (&check_only_regs, REGNO (new_reg));
  bitmap_set_bit (&check_only_regs, original_regno);
  bitmap_set_bit (&lra_split_regs, REGNO (new_reg));
  for (;;)
    {
      if (GET_CODE (next_usage_insns) != INSN_LIST)
        {
          usage_insn = next_usage_insns;
          break;
        }
      usage_insn = XEXP (next_usage_insns, 0);
      lra_assert (DEBUG_INSN_P (usage_insn));
      next_usage_insns = XEXP (next_usage_insns, 1);
      substitute_pseudo (&usage_insn, original_regno, new_reg);
      lra_update_insn_regno_info (usage_insn);
      if (lra_dump_file != NULL)
        {
          fprintf (lra_dump_file, "    Split reuse change %d->%d:\n",
                   original_regno, REGNO (new_reg));
          debug_rtl_slim (lra_dump_file, usage_insn, usage_insn,
                          -1, 0);
        }
    }
  lra_assert (NOTE_P (usage_insn) || NONDEBUG_INSN_P (usage_insn));
  lra_assert (usage_insn != insn || (after_p && before_p));
  lra_process_new_insns (usage_insn, after_p ? NULL_RTX : restore,
                         after_p ? restore : NULL_RTX,
                         call_save_p
                         ?  "Add reg<-save" : "Add reg<-split");
  lra_process_new_insns (insn, before_p ? save : NULL_RTX,
                         before_p ? NULL_RTX : save,
                         call_save_p
                         ?  "Add save<-reg" : "Add split<-reg");
  if (lra_dump_file != NULL)
    fprintf (lra_dump_file,
             "    ))))))))))))))))))))))))))))))))))))))))))))))))\n");
  return true;
}

/* Recognize that we need a split transformation for insn INSN, which
   defines or uses REGNO in its insn biggest MODE (we use it only if
   REGNO is a hard register).  POTENTIAL_RELOAD_HARD_REGS contains
   hard registers which might be used for reloads since the EBB end.
   Put the save before INSN if BEFORE_P is true.  MAX_UID is maximla
   uid before starting INSN processing.  Return true if we succeed in
   such transformation.  */
static bool
split_if_necessary (int regno, enum machine_mode mode,
                    HARD_REG_SET potential_reload_hard_regs,
                    bool before_p, rtx insn, int max_uid)
{
  bool res = false;
  int i, nregs = 1;
  rtx next_usage_insns;

  if (regno < FIRST_PSEUDO_REGISTER)
    nregs = hard_regno_nregs[regno][mode];
  for (i = 0; i < nregs; i++)
    if (usage_insns[regno + i].check == curr_usage_insns_check
        && (next_usage_insns = usage_insns[regno + i].insns) != NULL_RTX
        /* To avoid processing the register twice or more.  */
        && ((GET_CODE (next_usage_insns) != INSN_LIST
             && INSN_UID (next_usage_insns) < max_uid)
            || (GET_CODE (next_usage_insns) == INSN_LIST
                && (INSN_UID (XEXP (next_usage_insns, 0)) < max_uid)))
        && need_for_split_p (potential_reload_hard_regs, regno + i)
        && split_reg (before_p, regno + i, insn, next_usage_insns))
    res = true;
  return res;
}

/* Check only registers living at the current program point in the
   current EBB.  */
static bitmap_head live_regs;

/* Update live info in EBB given by its HEAD and TAIL insns after
   inheritance/split transformation.  The function removes dead moves
   too.  */
static void
update_ebb_live_info (rtx head, rtx tail)
{
  unsigned int j;
  int regno;
  bool live_p;
  rtx prev_insn, set;
  bool remove_p;
  basic_block last_bb, prev_bb, curr_bb;
  bitmap_iterator bi;
  struct lra_insn_reg *reg;
  edge e;
  edge_iterator ei;

  last_bb = BLOCK_FOR_INSN (tail); 
  prev_bb = NULL;
  for (curr_insn = tail;
       curr_insn != PREV_INSN (head);
       curr_insn = prev_insn)
    {
      prev_insn = PREV_INSN (curr_insn);
      /* We need to process empty blocks too.  They contain
         NOTE_INSN_BASIC_BLOCK referring for the basic block.  */
      if (NOTE_P (curr_insn) && NOTE_KIND (curr_insn) != NOTE_INSN_BASIC_BLOCK)
        continue;
      curr_bb = BLOCK_FOR_INSN (curr_insn);
      if (curr_bb != prev_bb)
        {
          if (prev_bb != NULL)
            {
              /* Update df_get_live_in (prev_bb):  */
              EXECUTE_IF_SET_IN_BITMAP (&check_only_regs, 0, j, bi)
                if (bitmap_bit_p (&live_regs, j))
                  bitmap_set_bit (df_get_live_in (prev_bb), j);
                else
                  bitmap_clear_bit (df_get_live_in (prev_bb), j);
            }
          if (curr_bb != last_bb)
            {
              /* Update df_get_live_out (curr_bb):  */
              EXECUTE_IF_SET_IN_BITMAP (&check_only_regs, 0, j, bi)
                {
                  live_p = bitmap_bit_p (&live_regs, j);
                  if (! live_p)
                    FOR_EACH_EDGE (e, ei, curr_bb->succs)
                      if (bitmap_bit_p (df_get_live_in (e->dest), j))
                        {
                          live_p = true;
                          break;
                        }
                  if (live_p)
                    bitmap_set_bit (df_get_live_out (curr_bb), j);
                  else
                    bitmap_clear_bit (df_get_live_out (curr_bb), j);
                }
            }
          prev_bb = curr_bb;
          bitmap_and (&live_regs, &check_only_regs, df_get_live_out (curr_bb));
        }
      if (! NONDEBUG_INSN_P (curr_insn))
        continue;
      curr_id = lra_get_insn_recog_data (curr_insn);
      remove_p = false;
      if ((set = single_set (curr_insn)) != NULL_RTX && REG_P (SET_DEST (set))
          && (regno = REGNO (SET_DEST (set))) >= FIRST_PSEUDO_REGISTER
          && bitmap_bit_p (&check_only_regs, regno)
          && ! bitmap_bit_p (&live_regs, regno))
        remove_p = true;
      /* See which defined values die here.  */
      for (reg = curr_id->regs; reg != NULL; reg = reg->next)
        if (reg->type == OP_OUT && ! reg->subreg_p)
          bitmap_clear_bit (&live_regs, reg->regno);
      /* Mark each used value as live.  */
      for (reg = curr_id->regs; reg != NULL; reg = reg->next)
        if (reg->type == OP_IN
            && bitmap_bit_p (&check_only_regs, reg->regno))
          bitmap_set_bit (&live_regs, reg->regno);
      /* It is quite important to remove dead move insns because it
         means removing dead store.  We don't need to process them for
         constraints.  */
      if (remove_p)
        {
          if (lra_dump_file != NULL)
            {
              fprintf (lra_dump_file, "     Removing dead insn:\n ");
              debug_rtl_slim (lra_dump_file, curr_insn, curr_insn, -1, 0);
            }
          lra_set_insn_deleted (curr_insn);
        }
    }
}

/* The structure describes info to do an inheritance for the current
   insn.  We need to collect such info first before doing the
   transformations because the transformations change the insn
   internal representation.  */
struct to_inherit
{
  /* Original regno.  */
  int regno;
  /* Subsequent insns which can inherit original reg value.  */
  rtx insns;
};

/* Array containing all info for doing inheritance from the current
   insn.  */
static struct to_inherit to_inherit[LRA_MAX_INSN_RELOADS];

/* Number elements in the previous array.  */
static int to_inherit_num;

/* Add inheritance info REGNO and INSNS. Their meaning is described in
   structure to_inherit.  */
static void
add_to_inherit (int regno, rtx insns)
{
  int i;

  for (i = 0; i < to_inherit_num; i++)
    if (to_inherit[i].regno == regno)
      return;
  lra_assert (to_inherit_num < LRA_MAX_INSN_RELOADS);
  to_inherit[to_inherit_num].regno = regno;
  to_inherit[to_inherit_num++].insns = insns;
}

/* Return the last non-debug insn in basic block BB, or the block begin
   note if none.  */
static rtx
get_last_insertion_point (basic_block bb)
{
  rtx insn;

  FOR_BB_INSNS_REVERSE (bb, insn)
    if (NONDEBUG_INSN_P (insn) || NOTE_INSN_BASIC_BLOCK_P (insn))
      return insn;
  gcc_unreachable ();
}

/* Set up RES by registers living on edges FROM except the edge (FROM,
   TO) or by registers set up in a jump insn in BB FROM.  */
static void
get_live_on_other_edges (basic_block from, basic_block to, bitmap res)
{
  rtx last;
  struct lra_insn_reg *reg;
  edge e;
  edge_iterator ei;

  lra_assert (to != NULL);
  bitmap_clear (res);
  FOR_EACH_EDGE (e, ei, from->succs)
    if (e->dest != to)
      bitmap_ior_into (res, df_get_live_in (e->dest));
  last = get_last_insertion_point (from);
  if (! JUMP_P (last))
    return;
  curr_id = lra_get_insn_recog_data (last);
  for (reg = curr_id->regs; reg != NULL; reg = reg->next)
    if (reg->type != OP_IN)
      bitmap_set_bit (res, reg->regno);
}
        
/* Used as a temporary results of some bitmap calculations.  */
static bitmap_head temp_bitmap;

/* Do inheritance/split transformations in EBB starting with HEAD and
   finishing on TAIL.  We process EBB insns in the reverse order.
   Return true if we did any inheritance/split transformation in the
   EBB.

   We should avoid excessive splitting which results in worse code
   because of inaccurate cost calculations for spilling new split
   pseudos in such case.  To achieve this we do splitting only if
   register pressure is high in given basic block and there are reload
   pseudos requiring hard registers.  We could do more register
   pressure calculations at any given program point to avoid necessary
   splitting even more but it is to expensive and the current approach
   works well enough.  */
static bool
inherit_in_ebb (rtx head, rtx tail)
{
  int i, src_regno, dst_regno, nregs;
  bool change_p, succ_p;
  rtx prev_insn, next_usage_insns, set, last_insn;
  enum reg_class cl;
  struct lra_insn_reg *reg;
  basic_block last_processed_bb, curr_bb = NULL;
  HARD_REG_SET potential_reload_hard_regs, live_hard_regs;
  bitmap to_process;
  unsigned int j;
  bitmap_iterator bi;
  bool head_p, after_p;

  change_p = false;
  curr_usage_insns_check++;
  reloads_num = calls_num = 0;
  bitmap_clear (&check_only_regs);
  last_processed_bb = NULL;
  CLEAR_HARD_REG_SET (potential_reload_hard_regs);
  CLEAR_HARD_REG_SET (live_hard_regs);
  /* We don't process new insns generated in the loop.  */
  for (curr_insn = tail; curr_insn != PREV_INSN (head); curr_insn = prev_insn)
    {
      prev_insn = PREV_INSN (curr_insn);
      if (BLOCK_FOR_INSN (curr_insn) != NULL)
        curr_bb = BLOCK_FOR_INSN (curr_insn);
      if (last_processed_bb != curr_bb)
        {
          /* We are at the end of BB.  Add qualified living
             pseudos for potential splitting.  */
          to_process = df_get_live_out (curr_bb);
          if (last_processed_bb != NULL)
            {   
              /* We are somewhere in the middle of EBB.  */
              get_live_on_other_edges (curr_bb, last_processed_bb,
                                       &temp_bitmap);
              to_process = &temp_bitmap;
            }
          last_processed_bb = curr_bb;
          last_insn = get_last_insertion_point (curr_bb);
          after_p = (! JUMP_P (last_insn)
                     && (! CALL_P (last_insn)
                         || (find_reg_note (last_insn,
                                           REG_NORETURN, NULL_RTX) == NULL_RTX
                             && ! SIBLING_CALL_P (last_insn))));
          REG_SET_TO_HARD_REG_SET (live_hard_regs, df_get_live_out (curr_bb));
          IOR_HARD_REG_SET (live_hard_regs, eliminable_regset);
          IOR_HARD_REG_SET (live_hard_regs, lra_no_alloc_regs);
          CLEAR_HARD_REG_SET (potential_reload_hard_regs);
          EXECUTE_IF_SET_IN_BITMAP (to_process, 0, j, bi)
            {
              if ((int) j >= lra_constraint_new_regno_start)
                break;
              if (j < FIRST_PSEUDO_REGISTER || reg_renumber[j] >= 0)
                {
                  if (j < FIRST_PSEUDO_REGISTER)
                    SET_HARD_REG_BIT (live_hard_regs, j);
                  else
                    add_to_hard_reg_set (&live_hard_regs,
                                         PSEUDO_REGNO_MODE (j),
                                         reg_renumber[j]);
                  setup_next_usage_insn (j, last_insn, reloads_num, after_p);
                }
            }
        }
      src_regno = dst_regno = -1;
      if (NONDEBUG_INSN_P (curr_insn)
          && (set = single_set (curr_insn)) != NULL_RTX
          && REG_P (SET_DEST (set)) && REG_P (SET_SRC (set)))
        {
          src_regno = REGNO (SET_SRC (set));
          dst_regno = REGNO (SET_DEST (set));
        }
      if (src_regno < lra_constraint_new_regno_start
          && src_regno >= FIRST_PSEUDO_REGISTER
          && reg_renumber[src_regno] < 0
          && dst_regno >= lra_constraint_new_regno_start
          && (cl = lra_get_allocno_class (dst_regno)) != NO_REGS)
        {
          /* 'reload_pseudo <- original_pseudo'.  */
          reloads_num++;
          succ_p = false;
          if (usage_insns[src_regno].check == curr_usage_insns_check
              && (next_usage_insns = usage_insns[src_regno].insns) != NULL_RTX)
            succ_p = inherit_reload_reg (false, src_regno, cl,
                                         curr_insn, next_usage_insns);
          if (succ_p)
            change_p = true;
          else
            setup_next_usage_insn (src_regno, curr_insn, reloads_num, false);
          if (hard_reg_set_subset_p (reg_class_contents[cl], live_hard_regs))
            IOR_HARD_REG_SET (potential_reload_hard_regs,
                              reg_class_contents[cl]);
        }
      else if (src_regno >= lra_constraint_new_regno_start
               && dst_regno < lra_constraint_new_regno_start
               && dst_regno >= FIRST_PSEUDO_REGISTER
               && reg_renumber[dst_regno] < 0
               && (cl = lra_get_allocno_class (src_regno)) != NO_REGS
               && usage_insns[dst_regno].check == curr_usage_insns_check
               && (next_usage_insns
                   = usage_insns[dst_regno].insns) != NULL_RTX)
        {
          reloads_num++;
          /* 'original_pseudo <- reload_pseudo'.  */
          if (! JUMP_P (curr_insn)
              && inherit_reload_reg (true, dst_regno, cl,
                                     curr_insn, next_usage_insns))
            change_p = true;
          /* Invalidate.  */
          usage_insns[dst_regno].check = 0;
          if (hard_reg_set_subset_p (reg_class_contents[cl], live_hard_regs))
            IOR_HARD_REG_SET (potential_reload_hard_regs,
                              reg_class_contents[cl]);
        }
      else if (INSN_P (curr_insn))
        {
          int max_uid = get_max_uid ();

          curr_id = lra_get_insn_recog_data (curr_insn);
          to_inherit_num = 0;
          /* Process insn definitions.  */
          for (reg = curr_id->regs; reg != NULL; reg = reg->next)
            if (reg->type != OP_IN
                && (dst_regno = reg->regno) < lra_constraint_new_regno_start)
              {
                if (dst_regno >= FIRST_PSEUDO_REGISTER && reg->type == OP_OUT
                    && reg_renumber[dst_regno] < 0 && ! reg->subreg_p
                    && usage_insns[dst_regno].check == curr_usage_insns_check
                    && (next_usage_insns
                        = usage_insns[dst_regno].insns) != NULL_RTX)
                  {
                    struct lra_insn_reg *r;
                    
                    for (r = curr_id->regs; r != NULL; r = r->next)
                      if (r->type != OP_OUT && r->regno == dst_regno)
                        break;
                    /* Don't do inheritance if the pseudo is also
                       used in the insn.  */
                    if (r == NULL)
                      /* We can not do inheritance right now
                         because the current insn reg info (chain
                         regs) can change after that.  */
                      add_to_inherit (dst_regno, next_usage_insns);
                  }
                /* We can not process one reg twice here because of
                   usage_insns invalidation.  */
                if ((dst_regno < FIRST_PSEUDO_REGISTER
                     || reg_renumber[dst_regno] >= 0)
                    && ! reg->subreg_p && reg->type == OP_OUT)
                  {
                    HARD_REG_SET s;
                    
                    if (split_if_necessary (dst_regno, reg->biggest_mode,
                                            potential_reload_hard_regs,
                                            false, curr_insn, max_uid))
                      change_p = true;
                    CLEAR_HARD_REG_SET (s);
                    if (dst_regno < FIRST_PSEUDO_REGISTER)
                      add_to_hard_reg_set (&s, reg->biggest_mode, dst_regno);
                    else
                      add_to_hard_reg_set (&s, PSEUDO_REGNO_MODE (dst_regno),
                                           reg_renumber[dst_regno]);
                    AND_COMPL_HARD_REG_SET (live_hard_regs, s);
                  }
                /* We should invalidate potential inheritance or
                   splitting for the current insn usages to the next
                   usage insns (see code below) as the output pseudo
                   prevents this.  */
                if ((dst_regno >= FIRST_PSEUDO_REGISTER
                     && reg_renumber[dst_regno] < 0)
                    || (reg->type == OP_OUT && ! reg->subreg_p
                        && (dst_regno < FIRST_PSEUDO_REGISTER
                            || reg_renumber[dst_regno] >= 0)))
                  {
                    /* Invalidate.  */
                    if (dst_regno >= FIRST_PSEUDO_REGISTER)
                      usage_insns[dst_regno].check = 0;
                    else
                      {
                        nregs = hard_regno_nregs[dst_regno][reg->biggest_mode];
                        for (i = 0; i < nregs; i++)
                          usage_insns[dst_regno + i].check = 0;
                      }
                  }
              }
          if (! JUMP_P (curr_insn))
            for (i = 0; i < to_inherit_num; i++)
              if (inherit_reload_reg (true, to_inherit[i].regno,
                                      ALL_REGS, curr_insn,
                                      to_inherit[i].insns))
              change_p = true;
          if (CALL_P (curr_insn))
            {
              rtx cheap, pat, dest, restore;
              int regno, hard_regno;

              calls_num++;
              if ((cheap = find_reg_note (curr_insn,
                                          REG_RETURNED, NULL_RTX)) != NULL_RTX
                  && ((cheap = XEXP (cheap, 0)), true)
                  && (regno = REGNO (cheap)) >= FIRST_PSEUDO_REGISTER
                  && (hard_regno = reg_renumber[regno]) >= 0
                  /* If there are pending saves/restores, the
                     optimization is not worth.  */
                  && usage_insns[regno].calls_num == calls_num - 1
                  && TEST_HARD_REG_BIT (call_used_reg_set, hard_regno))
                {
                  /* Restore the pseudo from the call result as
                     REG_RETURNED note says that the pseudo value is
                     in the call result and the pseudo is an argument
                     of the call.  */
                  pat = PATTERN (curr_insn);
                  if (GET_CODE (pat) == PARALLEL)
                    pat = XVECEXP (pat, 0, 0);
                  dest = SET_DEST (pat);
                  start_sequence ();
                  emit_move_insn (cheap, copy_rtx (dest));
                  restore = get_insns ();
                  end_sequence ();
                  lra_process_new_insns (curr_insn, NULL, restore,
                                         "Inserting call parameter restore");
                  /* We don't need to save/restore of the pseudo from
                     this call.  */
                  usage_insns[regno].calls_num = calls_num;
                  bitmap_set_bit (&check_only_regs, regno);
                }
            }
          to_inherit_num = 0;
          /* Process insn usages.  */
          for (reg = curr_id->regs; reg != NULL; reg = reg->next)
            if ((reg->type != OP_OUT
                 || (reg->type == OP_OUT && reg->subreg_p))
                && (src_regno = reg->regno) < lra_constraint_new_regno_start)
              {
                if (src_regno >= FIRST_PSEUDO_REGISTER
                    && reg_renumber[src_regno] < 0 && reg->type == OP_IN)
                  {
                    if (usage_insns[src_regno].check == curr_usage_insns_check
                        && (next_usage_insns
                            = usage_insns[src_regno].insns) != NULL_RTX
                        && NONDEBUG_INSN_P (curr_insn))
                      add_to_inherit (src_regno, next_usage_insns);
                    else
                      /* Add usages.  */
                      add_next_usage_insn (src_regno, curr_insn, reloads_num);
                  }
                else if (src_regno < FIRST_PSEUDO_REGISTER
                         || reg_renumber[src_regno] >= 0)
                  {
                    bool before_p;
                    rtx use_insn = curr_insn;

                    before_p = (JUMP_P (curr_insn)
                                || (CALL_P (curr_insn) && reg->type == OP_IN));
                    if (NONDEBUG_INSN_P (curr_insn)
                        && split_if_necessary (src_regno, reg->biggest_mode,
                                               potential_reload_hard_regs,
                                               before_p, curr_insn, max_uid))
                      {
                        if (reg->subreg_p)
                          lra_risky_transformations_p = true;
                        change_p = true;
                        /* Invalidate.  */
                        usage_insns[src_regno].check = 0;
                        if (before_p)
                          use_insn = PREV_INSN (curr_insn);
                      }
                    if (NONDEBUG_INSN_P (curr_insn))
                      {
                        if (src_regno < FIRST_PSEUDO_REGISTER)
                          add_to_hard_reg_set (&live_hard_regs,
                                               reg->biggest_mode, src_regno);
                        else
                          add_to_hard_reg_set (&live_hard_regs,
                                               PSEUDO_REGNO_MODE (src_regno),
                                               reg_renumber[src_regno]);
                      }
                    add_next_usage_insn (src_regno, use_insn, reloads_num);
                  }
              }
          for (i = 0; i < to_inherit_num; i++)
            {
              src_regno = to_inherit[i].regno;
              if (inherit_reload_reg (false, src_regno, ALL_REGS,
                                      curr_insn, to_inherit[i].insns))
                change_p = true;
              else
                setup_next_usage_insn (src_regno, curr_insn, reloads_num, false);
            }
        }
      /* We reached the start of the current basic block.  */
      if (prev_insn == NULL_RTX || prev_insn == PREV_INSN (head)
          || BLOCK_FOR_INSN (prev_insn) != curr_bb)
        {
          /* We reached the beginning of the current block -- do
             rest of spliting in the current BB.  */
          to_process = df_get_live_in (curr_bb);
          if (BLOCK_FOR_INSN (head) != curr_bb)
            {   
              /* We are somewhere in the middle of EBB.  */
              get_live_on_other_edges (EDGE_PRED (curr_bb, 0)->src,
                                       curr_bb, &temp_bitmap);
              to_process = &temp_bitmap;
            }
          head_p = true;
          EXECUTE_IF_SET_IN_BITMAP (to_process, 0, j, bi)
            {
              if ((int) j >= lra_constraint_new_regno_start)
                break;
              if (((int) j < FIRST_PSEUDO_REGISTER || reg_renumber[j] >= 0)
                  && usage_insns[j].check == curr_usage_insns_check
                  && (next_usage_insns = usage_insns[j].insns) != NULL_RTX)
                {
                  if (need_for_split_p (potential_reload_hard_regs, j))
                    {
                      if (lra_dump_file != NULL && head_p)
                        {
                          fprintf (lra_dump_file,
                                   "  ----------------------------------\n");
                          head_p = false;
                        }
                      if (split_reg (false, j, bb_note (curr_bb),
                                     next_usage_insns))
                        change_p = true;
                    }
                  usage_insns[j].check = 0;
                }
            }
        }
    }
  return change_p;
}

/* This value affects EBB forming.  If probability of edge from EBB to
   a BB is not greater than the following value, we don't add the BB
   to EBB.  */ 
#define EBB_PROBABILITY_CUTOFF (REG_BR_PROB_BASE / 2)

/* Current number of inheritance/split iteration.  */
int lra_inheritance_iter;

/* Entry function for inheritance/split pass.  */
void
lra_inheritance (void)
{
  int i;
  basic_block bb, start_bb;
  edge e;

  timevar_push (TV_LRA_INHERITANCE);
  lra_inheritance_iter++;
  if (lra_dump_file != NULL)
    fprintf (lra_dump_file, "\n********** Inheritance #%d: **********\n\n",
             lra_inheritance_iter);
  curr_usage_insns_check = 0;
  usage_insns = XNEWVEC (struct usage_insns, lra_constraint_new_regno_start);
  for (i = 0; i < lra_constraint_new_regno_start; i++)
    usage_insns[i].check = 0;
  bitmap_initialize (&check_only_regs, &reg_obstack);
  bitmap_initialize (&live_regs, &reg_obstack);
  bitmap_initialize (&temp_bitmap, &reg_obstack);
  bitmap_initialize (&ebb_global_regs, &reg_obstack);
  FOR_EACH_BB (bb)
    {
      start_bb = bb;
      if (lra_dump_file != NULL)
        fprintf (lra_dump_file, "EBB");
      /* Form a EBB starting with BB.  */
      bitmap_clear (&ebb_global_regs);
      bitmap_ior_into (&ebb_global_regs, df_get_live_in (bb));
      for (;;)
        {
          if (lra_dump_file != NULL)
            fprintf (lra_dump_file, " %d", bb->index);
          if (bb->next_bb == EXIT_BLOCK_PTR || LABEL_P (BB_HEAD (bb->next_bb)))
            break;
          e = find_fallthru_edge (bb->succs);
          if (! e)
            break;
          if (e->probability <= EBB_PROBABILITY_CUTOFF)
            break;
          bb = bb->next_bb;
        }
      bitmap_ior_into (&ebb_global_regs, df_get_live_out (bb));
      if (lra_dump_file != NULL)
        fprintf (lra_dump_file, "\n");
      if (inherit_in_ebb (BB_HEAD (start_bb), BB_END (bb)))
        /* Remember that the EBB head and tail can change in
           inherit_in_ebb.  */
        update_ebb_live_info (BB_HEAD (start_bb), BB_END (bb));
    }
  bitmap_clear (&ebb_global_regs);
  bitmap_clear (&temp_bitmap);
  bitmap_clear (&live_regs);
  bitmap_clear (&check_only_regs);
  free (usage_insns);

  timevar_pop (TV_LRA_INHERITANCE);
}

\f

/* This page contains code to undo failed inheritance/split
   transformations.  */

/* Current number of iteration undoing inheritance/split.  */
int lra_undo_inheritance_iter;

/* Fix BB live info LIVE after removing pseudos created on pass doing
   inheritance/split which are REMOVED_PSEUDOS.  */
static void
fix_bb_live_info (bitmap live, bitmap removed_pseudos)
{
  unsigned int regno;
  bitmap_iterator bi;

  EXECUTE_IF_SET_IN_BITMAP (removed_pseudos, 0, regno, bi)
    if (bitmap_clear_bit (live, regno))
      bitmap_set_bit (live, lra_reg_info[regno].restore_regno);
}

/* Return regno of the (subreg of) REG. Otherwise, return a negative
   number.  */
static int
get_regno (rtx reg)
{
  if (GET_CODE (reg) == SUBREG)
    reg = SUBREG_REG (reg);
  if (REG_P (reg))
    return REGNO (reg);
  return -1;
}

/* Remove inheritance/split pseudos which are in REMOVE_PSEUDOS and
   return true if we did any change.  The undo transformations for
   inheritance looks like
      i <- i2
      p <- i      =>   p <- i2
   or removing
      p <- i, i <- p, and i <- i3
   where p is original pseudo from which inheritance pseudo i was
   created, i and i3 are removed inheritance pseudos, i2 is another
   not removed inheritance pseudo.  All split pseudos or other
   occurrences of removed inheritance pseudos are changed on the
   corresponding original pseudos.

   The function also schedules insns changed and created during
   inheritance/split pass for processing by the subsequent constraint
   pass.  */
static bool
remove_inheritance_pseudos (bitmap remove_pseudos)
{
  basic_block bb;
  int regno, sregno, prev_sregno, dregno, restore_regno;
  rtx set, prev_set, prev_insn;
  bool change_p, done_p;

  change_p = ! bitmap_empty_p (remove_pseudos);
  /* We can not finish the function right away if CHANGE_P is true
     because we need to marks insns affected by previous
     inheritance/split pass for processing by the subsequent
     constraint pass.  */
  FOR_EACH_BB (bb)
    {
      fix_bb_live_info (df_get_live_in (bb), remove_pseudos);
      fix_bb_live_info (df_get_live_out (bb), remove_pseudos);
      FOR_BB_INSNS_REVERSE (bb, curr_insn)
        {
          if (! INSN_P (curr_insn))
            continue;
          done_p = false;
          sregno = dregno = -1;
          if (change_p && NONDEBUG_INSN_P (curr_insn)
              && (set = single_set (curr_insn)) != NULL_RTX)
            {
              dregno = get_regno (SET_DEST (set));
              sregno = get_regno (SET_SRC (set));
            }
          
          if (sregno >= 0 && dregno >= 0)
            {
              if ((bitmap_bit_p (remove_pseudos, sregno)
                   && (lra_reg_info[sregno].restore_regno == dregno
                       || (bitmap_bit_p (remove_pseudos, dregno)
                           && (lra_reg_info[sregno].restore_regno
                               == lra_reg_info[dregno].restore_regno))))
                  || (bitmap_bit_p (remove_pseudos, dregno)
                      && lra_reg_info[dregno].restore_regno == sregno))
                /* One of the following cases:
                     original <- removed inheritance pseudo
                     removed inherit pseudo <- another removed inherit pseudo
                     removed inherit pseudo <- original pseudo
                   Or
                     removed_split_pseudo <- original_reg
                     original_reg <- removed_split_pseudo */
                {
                  if (lra_dump_file != NULL)
                    {
                      fprintf (lra_dump_file, "    Removing %s:\n",
                               bitmap_bit_p (&lra_split_regs, sregno)
                               || bitmap_bit_p (&lra_split_regs, dregno)
                               ? "split" : "inheritance");
                      debug_rtl_slim (lra_dump_file,
                                      curr_insn, curr_insn, -1, 0);
                    }
                  lra_set_insn_deleted (curr_insn);
                  done_p = true;
                }
              else if (bitmap_bit_p (remove_pseudos, sregno)
                       && bitmap_bit_p (&lra_inheritance_pseudos, sregno))
                {
                  /* Search the following pattern:
                       inherit_or_split_pseudo1 <- inherit_or_split_pseudo2
                       original_pseudo <- inherit_or_split_pseudo1
                    where the 2nd insn is the current insn and
                    inherit_or_split_pseudo2 is not removed.  If it is found,
                    change the current insn onto:
                       original_pseudo <- inherit_or_split_pseudo2.  */
                  for (prev_insn = PREV_INSN (curr_insn);
                       prev_insn != NULL_RTX && ! NONDEBUG_INSN_P (prev_insn);
                       prev_insn = PREV_INSN (prev_insn))
                    ;
                  if (prev_insn != NULL_RTX && BLOCK_FOR_INSN (prev_insn) == bb
                      && (prev_set = single_set (prev_insn)) != NULL_RTX
                      /* There should be no subregs in insn we are
                         searching because only the original reg might
                         be in subreg when we changed the mode of
                         load/store for splitting.  */
                      && REG_P (SET_DEST (prev_set))
                      && REG_P (SET_SRC (prev_set))
                      && (int) REGNO (SET_DEST (prev_set)) == sregno
                      && ((prev_sregno = REGNO (SET_SRC (prev_set)))
                          >= FIRST_PSEUDO_REGISTER)
                      /* As we consider chain of inheritance or
                         splitting described in above comment we should
                         check that sregno and prev_sregno were
                         inheritance/split pseudos created from the
                         same original regno.  */
                      && (lra_reg_info[sregno].restore_regno
                          == lra_reg_info[prev_sregno].restore_regno)
                      && ! bitmap_bit_p (remove_pseudos, prev_sregno))
                    {
                      lra_assert (GET_MODE (SET_SRC (prev_set))
                                  == GET_MODE (regno_reg_rtx[sregno]));
                      if (GET_CODE (SET_SRC (set)) == SUBREG)
                        SUBREG_REG (SET_SRC (set)) = SET_SRC (prev_set);
                      else
                        SET_SRC (set) = SET_SRC (prev_set);
                      lra_push_insn_and_update_insn_regno_info (curr_insn);
                      lra_set_used_insn_alternative_by_uid
                        (INSN_UID (curr_insn), -1);
                      done_p = true;
                      if (lra_dump_file != NULL)
                        {
                          fprintf (lra_dump_file, "    Change reload insn:\n");
                          debug_rtl_slim (lra_dump_file,
                                          curr_insn, curr_insn, -1, 0);
                        }
                    }
                }
            }
          if (! done_p)
            {
              struct lra_insn_reg *reg;
              bool restored_regs_p = false;
              bool kept_regs_p = false;

              curr_id = lra_get_insn_recog_data (curr_insn);
              for (reg = curr_id->regs; reg != NULL; reg = reg->next)
                {
                  regno = reg->regno;
                  restore_regno = lra_reg_info[regno].restore_regno;
                  if (restore_regno >= 0)
                    {
                      if (change_p && bitmap_bit_p (remove_pseudos, regno))
                        {
                          substitute_pseudo (&curr_insn, regno,
                                             regno_reg_rtx[restore_regno]);
                          restored_regs_p = true;
                        }
                      else
                        kept_regs_p = true;
                    }
                }
              if (NONDEBUG_INSN_P (curr_insn) && kept_regs_p)
                {
                  /* The instruction has changed since the previous
                     constraints pass.  */
                  lra_push_insn_and_update_insn_regno_info (curr_insn);
                  lra_set_used_insn_alternative_by_uid
                    (INSN_UID (curr_insn), -1);
                }
              else if (restored_regs_p)
                /* The instruction has been restored to the form that
                   it had during the previous constraints pass.  */
                lra_update_insn_regno_info (curr_insn);
              if (restored_regs_p && lra_dump_file != NULL)
                {
                  fprintf (lra_dump_file, "   Insn after restoring regs:\n");
                  debug_rtl_slim (lra_dump_file, curr_insn, curr_insn, -1, 0);
                }
            }
        }
    }
  return change_p;
}

/* Entry function for undoing inheritance/split transformation.  Return true
   if we did any RTL change in this pass.  */
bool
lra_undo_inheritance (void)
{
  unsigned int regno;
  int restore_regno, hard_regno;
  int n_all_inherit, n_inherit, n_all_split, n_split;
  bitmap_head remove_pseudos;
  bitmap_iterator bi;
  bool change_p;

  lra_undo_inheritance_iter++;
  if (lra_dump_file != NULL)
    fprintf (lra_dump_file,
             "\n********** Undoing inheritance #%d: **********\n\n",
             lra_undo_inheritance_iter);
  bitmap_initialize (&remove_pseudos, &reg_obstack);
  n_inherit = n_all_inherit = 0;
  EXECUTE_IF_SET_IN_BITMAP (&lra_inheritance_pseudos, 0, regno, bi)
    if (lra_reg_info[regno].restore_regno >= 0)
      {
        n_all_inherit++;
        if (reg_renumber[regno] < 0)
          bitmap_set_bit (&remove_pseudos, regno);
        else
          n_inherit++;
      }
  if (lra_dump_file != NULL && n_all_inherit != 0)
    fprintf (lra_dump_file, "Inherit %d out of %d (%.2f%%)\n",
             n_inherit, n_all_inherit,
             (double) n_inherit / n_all_inherit * 100);
  n_split = n_all_split = 0;
  EXECUTE_IF_SET_IN_BITMAP (&lra_split_regs, 0, regno, bi)
    if ((restore_regno = lra_reg_info[regno].restore_regno) >= 0)
      {
        n_all_split++;
        hard_regno = (restore_regno >= FIRST_PSEUDO_REGISTER
                      ? reg_renumber[restore_regno] : restore_regno);
        if (hard_regno < 0 || reg_renumber[regno] == hard_regno)
          bitmap_set_bit (&remove_pseudos, regno);
        else
          {
            n_split++;
            if (lra_dump_file != NULL)
              fprintf (lra_dump_file, "      Keep split r%d (orig=r%d)\n",
                       regno, restore_regno);
          }
      }
  if (lra_dump_file != NULL && n_all_split != 0)
    fprintf (lra_dump_file, "Split %d out of %d (%.2f%%)\n",
             n_split, n_all_split,
             (double) n_split / n_all_split * 100);
  change_p = remove_inheritance_pseudos (&remove_pseudos);
  bitmap_clear (&remove_pseudos);
  /* Clear restore_regnos.  */
  EXECUTE_IF_SET_IN_BITMAP (&lra_inheritance_pseudos, 0, regno, bi)
    lra_reg_info[regno].restore_regno = -1;
  EXECUTE_IF_SET_IN_BITMAP (&lra_split_regs, 0, regno, bi)
    lra_reg_info[regno].restore_regno = -1;
  return change_p;
}