gcc/ChangeLog:

[official-gcc.git] / gcc / config / s390 / s390.c

/* Subroutines used for code generation on IBM S/390 and zSeries
   Copyright (C) 1999, 2000, 2001, 2002, 2003, 2004
   Free Software Foundation, Inc.
   Contributed by Hartmut Penner (hpenner@de.ibm.com) and
                  Ulrich Weigand (uweigand@de.ibm.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 2, or (at your option) any later
version.

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

You should have received a copy of the GNU General Public License
along with GCC; see the file COPYING.  If not, write to the Free
Software Foundation, 59 Temple Place - Suite 330, Boston, MA
02111-1307, USA.  */

#include "config.h"
#include "system.h"
#include "coretypes.h"
#include "tm.h"
#include "rtl.h"
#include "tree.h"
#include "tm_p.h"
#include "regs.h"
#include "hard-reg-set.h"
#include "real.h"
#include "insn-config.h"
#include "conditions.h"
#include "output.h"
#include "insn-attr.h"
#include "flags.h"
#include "except.h"
#include "function.h"
#include "recog.h"
#include "expr.h"
#include "reload.h"
#include "toplev.h"
#include "basic-block.h"
#include "integrate.h"
#include "ggc.h"
#include "target.h"
#include "target-def.h"
#include "debug.h"
#include "langhooks.h"
#include "optabs.h"
#include "tree-gimple.h"

/* Machine-specific symbol_ref flags.  */
#define SYMBOL_FLAG_ALIGN1      (SYMBOL_FLAG_MACH_DEP << 0)


static bool s390_assemble_integer (rtx, unsigned int, int);
static void s390_select_rtx_section (enum machine_mode, rtx,
                                     unsigned HOST_WIDE_INT);
static void s390_encode_section_info (tree, rtx, int);
static bool s390_cannot_force_const_mem (rtx);
static rtx s390_delegitimize_address (rtx);
static bool s390_return_in_memory (tree, tree);
static void s390_init_builtins (void);
static rtx s390_expand_builtin (tree, rtx, rtx, enum machine_mode, int);
static void s390_output_mi_thunk (FILE *, tree, HOST_WIDE_INT,
                                  HOST_WIDE_INT, tree);
static enum attr_type s390_safe_attr_type (rtx);

static int s390_adjust_cost (rtx, rtx, rtx, int);
static int s390_adjust_priority (rtx, int);
static int s390_issue_rate (void);
static int s390_first_cycle_multipass_dfa_lookahead (void);
static bool s390_rtx_costs (rtx, int, int, int *);
static int s390_address_cost (rtx);
static void s390_reorg (void);
static bool s390_valid_pointer_mode (enum machine_mode);
static tree s390_build_builtin_va_list (void);
static tree s390_gimplify_va_arg (tree, tree, tree *, tree *);
static bool s390_function_ok_for_sibcall (tree, tree);
static bool s390_call_saved_register_used (tree);

#undef  TARGET_ASM_ALIGNED_HI_OP
#define TARGET_ASM_ALIGNED_HI_OP "\t.word\t"
#undef  TARGET_ASM_ALIGNED_DI_OP
#define TARGET_ASM_ALIGNED_DI_OP "\t.quad\t"
#undef  TARGET_ASM_INTEGER
#define TARGET_ASM_INTEGER s390_assemble_integer

#undef  TARGET_ASM_OPEN_PAREN
#define TARGET_ASM_OPEN_PAREN ""

#undef  TARGET_ASM_CLOSE_PAREN
#define TARGET_ASM_CLOSE_PAREN ""

#undef  TARGET_ASM_SELECT_RTX_SECTION
#define TARGET_ASM_SELECT_RTX_SECTION  s390_select_rtx_section

#undef  TARGET_ENCODE_SECTION_INFO
#define TARGET_ENCODE_SECTION_INFO s390_encode_section_info

#ifdef HAVE_AS_TLS
#undef TARGET_HAVE_TLS
#define TARGET_HAVE_TLS true
#endif
#undef TARGET_CANNOT_FORCE_CONST_MEM
#define TARGET_CANNOT_FORCE_CONST_MEM s390_cannot_force_const_mem

#undef TARGET_DELEGITIMIZE_ADDRESS
#define TARGET_DELEGITIMIZE_ADDRESS s390_delegitimize_address

#undef TARGET_RETURN_IN_MEMORY
#define TARGET_RETURN_IN_MEMORY s390_return_in_memory

#undef  TARGET_INIT_BUILTINS
#define TARGET_INIT_BUILTINS s390_init_builtins
#undef  TARGET_EXPAND_BUILTIN
#define TARGET_EXPAND_BUILTIN s390_expand_builtin

#undef TARGET_ASM_OUTPUT_MI_THUNK
#define TARGET_ASM_OUTPUT_MI_THUNK s390_output_mi_thunk
#undef TARGET_ASM_CAN_OUTPUT_MI_THUNK
#define TARGET_ASM_CAN_OUTPUT_MI_THUNK hook_bool_tree_hwi_hwi_tree_true

#undef  TARGET_SCHED_ADJUST_COST
#define TARGET_SCHED_ADJUST_COST s390_adjust_cost
#undef  TARGET_SCHED_ADJUST_PRIORITY
#define TARGET_SCHED_ADJUST_PRIORITY s390_adjust_priority
#undef TARGET_SCHED_ISSUE_RATE
#define TARGET_SCHED_ISSUE_RATE s390_issue_rate
#undef TARGET_SCHED_USE_DFA_PIPELINE_INTERFACE
#define TARGET_SCHED_USE_DFA_PIPELINE_INTERFACE hook_int_void_1
#undef TARGET_SCHED_FIRST_CYCLE_MULTIPASS_DFA_LOOKAHEAD
#define TARGET_SCHED_FIRST_CYCLE_MULTIPASS_DFA_LOOKAHEAD s390_first_cycle_multipass_dfa_lookahead

#undef TARGET_RTX_COSTS
#define TARGET_RTX_COSTS s390_rtx_costs
#undef TARGET_ADDRESS_COST
#define TARGET_ADDRESS_COST s390_address_cost

#undef TARGET_MACHINE_DEPENDENT_REORG
#define TARGET_MACHINE_DEPENDENT_REORG s390_reorg

#undef TARGET_VALID_POINTER_MODE
#define TARGET_VALID_POINTER_MODE s390_valid_pointer_mode

#undef TARGET_BUILD_BUILTIN_VA_LIST
#define TARGET_BUILD_BUILTIN_VA_LIST s390_build_builtin_va_list
#undef TARGET_GIMPLIFY_VA_ARG_EXPR
#define TARGET_GIMPLIFY_VA_ARG_EXPR s390_gimplify_va_arg

#undef TARGET_PROMOTE_FUNCTION_ARGS
#define TARGET_PROMOTE_FUNCTION_ARGS hook_bool_tree_true
#undef TARGET_PROMOTE_FUNCTION_RETURN
#define TARGET_PROMOTE_FUNCTION_RETURN hook_bool_tree_true

#undef TARGET_FUNCTION_OK_FOR_SIBCALL
#define TARGET_FUNCTION_OK_FOR_SIBCALL s390_function_ok_for_sibcall

struct gcc_target targetm = TARGET_INITIALIZER;

extern int reload_completed;

/* The alias set for prologue/epilogue register save/restore.  */
static int s390_sr_alias_set = 0;

/* Save information from a "cmpxx" operation until the branch or scc is
   emitted.  */
rtx s390_compare_op0, s390_compare_op1;

/* Structure used to hold the components of a S/390 memory
   address.  A legitimate address on S/390 is of the general
   form
          base + index + displacement
   where any of the components is optional.

   base and index are registers of the class ADDR_REGS,
   displacement is an unsigned 12-bit immediate constant.  */

struct s390_address
{
  rtx base;
  rtx indx;
  rtx disp;
  int pointer;
};

/* Which cpu are we tuning for.  */
enum processor_type s390_tune;
enum processor_flags s390_tune_flags;
/* Which instruction set architecture to use.  */
enum processor_type s390_arch;
enum processor_flags s390_arch_flags;

/* Strings to hold which cpu and instruction set architecture  to use.  */
const char *s390_tune_string;           /* for -mtune=<xxx> */
const char *s390_arch_string;           /* for -march=<xxx> */

/* Define the structure for the machine field in struct function.  */

struct machine_function GTY(())
{
  /* Set, if some of the fprs 8-15 need to be saved (64 bit abi).  */
  int save_fprs_p;

  /* Set if return address needs to be saved.  */
  bool save_return_addr_p;

  /* Number of first and last gpr to be saved, restored.  */
  int first_save_gpr;
  int first_restore_gpr;
  int last_save_gpr;
  int last_restore_gpr;

  /* Size of stack frame.  */
  HOST_WIDE_INT frame_size;

  /* Literal pool base register.  */
  rtx base_reg;

  /* Some local-dynamic TLS symbol name.  */
  const char *some_ld_name;
};

static int s390_match_ccmode_set (rtx, enum machine_mode);
static int s390_branch_condition_mask (rtx);
static const char *s390_branch_condition_mnemonic (rtx, int);
static int check_mode (rtx, enum machine_mode *);
static int general_s_operand (rtx, enum machine_mode, int);
static int s390_short_displacement (rtx);
static int s390_decompose_address (rtx, struct s390_address *);
static rtx get_thread_pointer (void);
static rtx legitimize_tls_address (rtx, rtx);
static void print_shift_count_operand (FILE *, rtx);
static const char *get_some_local_dynamic_name (void);
static int get_some_local_dynamic_name_1 (rtx *, void *);
static int reg_used_in_mem_p (int, rtx);
static int addr_generation_dependency_p (rtx, rtx);
static int s390_split_branches (void);
static void annotate_constant_pool_refs (rtx *x);
static void find_constant_pool_ref (rtx, rtx *);
static void replace_constant_pool_ref (rtx *, rtx, rtx);
static rtx find_ltrel_base (rtx);
static void replace_ltrel_base (rtx *);
static void s390_optimize_prolog (bool);
static int find_unused_clobbered_reg (void);
static void s390_frame_info (int, int);
static rtx save_fpr (rtx, int, int);
static rtx restore_fpr (rtx, int, int);
static rtx save_gprs (rtx, int, int, int);
static rtx restore_gprs (rtx, int, int, int);
static int s390_function_arg_size (enum machine_mode, tree);
static bool s390_function_arg_float (enum machine_mode, tree);
static struct machine_function * s390_init_machine_status (void);

/* Check whether integer displacement is in range.  */
#define DISP_IN_RANGE(d) \
  (TARGET_LONG_DISPLACEMENT? ((d) >= -524288 && (d) <= 524287) \
                           : ((d) >= 0 && (d) <= 4095))

/* Return true if SET either doesn't set the CC register, or else
   the source and destination have matching CC modes and that
   CC mode is at least as constrained as REQ_MODE.  */

static int
s390_match_ccmode_set (rtx set, enum machine_mode req_mode)
{
  enum machine_mode set_mode;

  if (GET_CODE (set) != SET)
    abort ();

  if (GET_CODE (SET_DEST (set)) != REG || !CC_REGNO_P (REGNO (SET_DEST (set))))
    return 1;

  set_mode = GET_MODE (SET_DEST (set));
  switch (set_mode)
    {
    case CCSmode:
    case CCSRmode:
    case CCUmode:
    case CCURmode:
    case CCLmode:
    case CCL1mode:
    case CCL2mode:
    case CCL3mode:
    case CCT1mode:
    case CCT2mode:
    case CCT3mode:
      if (req_mode != set_mode)
        return 0;
      break;

    case CCZmode:
      if (req_mode != CCSmode && req_mode != CCUmode && req_mode != CCTmode
          && req_mode != CCSRmode && req_mode != CCURmode)
        return 0;
      break;

    case CCAPmode:
    case CCANmode:
      if (req_mode != CCAmode)
        return 0;
      break;

    default:
      abort ();
    }

  return (GET_MODE (SET_SRC (set)) == set_mode);
}

/* Return true if every SET in INSN that sets the CC register
   has source and destination with matching CC modes and that
   CC mode is at least as constrained as REQ_MODE.
   If REQ_MODE is VOIDmode, always return false.  */

int
s390_match_ccmode (rtx insn, enum machine_mode req_mode)
{
  int i;

  /* s390_tm_ccmode returns VOIDmode to indicate failure.  */
  if (req_mode == VOIDmode)
    return 0;

  if (GET_CODE (PATTERN (insn)) == SET)
    return s390_match_ccmode_set (PATTERN (insn), req_mode);

  if (GET_CODE (PATTERN (insn)) == PARALLEL)
      for (i = 0; i < XVECLEN (PATTERN (insn), 0); i++)
        {
          rtx set = XVECEXP (PATTERN (insn), 0, i);
          if (GET_CODE (set) == SET)
            if (!s390_match_ccmode_set (set, req_mode))
              return 0;
        }

  return 1;
}

/* If a test-under-mask instruction can be used to implement
   (compare (and ... OP1) OP2), return the CC mode required
   to do that.  Otherwise, return VOIDmode.
   MIXED is true if the instruction can distinguish between
   CC1 and CC2 for mixed selected bits (TMxx), it is false
   if the instruction cannot (TM).  */

enum machine_mode
s390_tm_ccmode (rtx op1, rtx op2, int mixed)
{
  int bit0, bit1;

  /* ??? Fixme: should work on CONST_DOUBLE as well.  */
  if (GET_CODE (op1) != CONST_INT || GET_CODE (op2) != CONST_INT)
    return VOIDmode;

  /* Selected bits all zero: CC0.  */
  if (INTVAL (op2) == 0)
    return CCTmode;

  /* Selected bits all one: CC3.  */
  if (INTVAL (op2) == INTVAL (op1))
    return CCT3mode;

  /* Exactly two bits selected, mixed zeroes and ones: CC1 or CC2.  */
  if (mixed)
    {
      bit1 = exact_log2 (INTVAL (op2));
      bit0 = exact_log2 (INTVAL (op1) ^ INTVAL (op2));
      if (bit0 != -1 && bit1 != -1)
        return bit0 > bit1 ? CCT1mode : CCT2mode;
    }

  return VOIDmode;
}

/* Given a comparison code OP (EQ, NE, etc.) and the operands
   OP0 and OP1 of a COMPARE, return the mode to be used for the
   comparison.  */

enum machine_mode
s390_select_ccmode (enum rtx_code code, rtx op0, rtx op1)
{
  switch (code)
    {
      case EQ:
      case NE:
        if (GET_CODE (op0) == PLUS && GET_CODE (XEXP (op0, 1)) == CONST_INT
            && CONST_OK_FOR_CONSTRAINT_P (INTVAL (XEXP (op0, 1)), 'K', "K"))
          return CCAPmode;
        if ((GET_CODE (op0) == PLUS || GET_CODE (op0) == MINUS
             || GET_CODE (op1) == NEG)
            && GET_MODE_CLASS (GET_MODE (op0)) == MODE_INT)
          return CCLmode;

        if (GET_CODE (op0) == AND)
          {
            /* Check whether we can potentially do it via TM.  */
            enum machine_mode ccmode;
            ccmode = s390_tm_ccmode (XEXP (op0, 1), op1, 1);
            if (ccmode != VOIDmode)
              {
                /* Relax CCTmode to CCZmode to allow fall-back to AND
                   if that turns out to be beneficial.  */
                return ccmode == CCTmode ? CCZmode : ccmode;
              }
          }

        if (register_operand (op0, HImode)
            && GET_CODE (op1) == CONST_INT
            && (INTVAL (op1) == -1 || INTVAL (op1) == 65535))
          return CCT3mode;
        if (register_operand (op0, QImode)
            && GET_CODE (op1) == CONST_INT
            && (INTVAL (op1) == -1 || INTVAL (op1) == 255))
          return CCT3mode;

        return CCZmode;

      case LE:
      case LT:
      case GE:
      case GT:
          if (GET_CODE (op0) == PLUS && GET_CODE (XEXP (op0, 1)) == CONST_INT
              && CONST_OK_FOR_CONSTRAINT_P (INTVAL (XEXP (op0, 1)), 'K', "K"))
            {
              if (INTVAL (XEXP((op0), 1)) < 0)
                return CCANmode;
              else
                return CCAPmode;
            }
      case UNORDERED:
      case ORDERED:
      case UNEQ:
      case UNLE:
      case UNLT:
      case UNGE:
      case UNGT:
      case LTGT:
        if ((GET_CODE (op0) == SIGN_EXTEND || GET_CODE (op0) == ZERO_EXTEND)
            && GET_CODE (op1) != CONST_INT)
          return CCSRmode;
        return CCSmode;

      case LTU:
      case GEU:
        if (GET_CODE (op0) == PLUS
            && GET_MODE_CLASS (GET_MODE (op0)) == MODE_INT)
          return CCL1mode;

        if ((GET_CODE (op0) == SIGN_EXTEND || GET_CODE (op0) == ZERO_EXTEND)
            && GET_CODE (op1) != CONST_INT)
          return CCURmode;
        return CCUmode;

      case LEU:
      case GTU:
        if (GET_CODE (op0) == MINUS
            && GET_MODE_CLASS (GET_MODE (op0)) == MODE_INT)
          return CCL2mode;

        if ((GET_CODE (op0) == SIGN_EXTEND || GET_CODE (op0) == ZERO_EXTEND)
            && GET_CODE (op1) != CONST_INT)
          return CCURmode;
        return CCUmode;

      default:
        abort ();
    }
}

/* Emit a compare instruction suitable to implement the comparison
   OP0 CODE OP1.  Return the correct condition RTL to be placed in
   the IF_THEN_ELSE of the conditional branch testing the result.  */

rtx
s390_emit_compare (enum rtx_code code, rtx op0, rtx op1)
{
  enum machine_mode mode = s390_select_ccmode (code, op0, op1);
  rtx cc = gen_rtx_REG (mode, CC_REGNUM);

  emit_insn (gen_rtx_SET (VOIDmode, cc, gen_rtx_COMPARE (mode, op0, op1)));
  return gen_rtx_fmt_ee (code, VOIDmode, cc, const0_rtx);
}

/* Emit a jump instruction to TARGET.  If COND is NULL_RTX, emit an
   unconditional jump, else a conditional jump under condition COND.  */

void
s390_emit_jump (rtx target, rtx cond)
{
  rtx insn;

  target = gen_rtx_LABEL_REF (VOIDmode, target);
  if (cond)
    target = gen_rtx_IF_THEN_ELSE (VOIDmode, cond, target, pc_rtx);

  insn = gen_rtx_SET (VOIDmode, pc_rtx, target);
  emit_jump_insn (insn);
}

/* Return nonzero if OP is a valid comparison operator
   for an ALC condition in mode MODE.  */

int
s390_alc_comparison (rtx op, enum machine_mode mode)
{
  if (mode != VOIDmode && mode != GET_MODE (op))
    return 0;

  while (GET_CODE (op) == ZERO_EXTEND || GET_CODE (op) == SIGN_EXTEND)
    op = XEXP (op, 0);

  if (!COMPARISON_P (op))
    return 0;

  if (GET_CODE (XEXP (op, 0)) != REG
      || REGNO (XEXP (op, 0)) != CC_REGNUM
      || XEXP (op, 1) != const0_rtx)
    return 0;

  switch (GET_MODE (XEXP (op, 0)))
    {
    case CCL1mode:
      return GET_CODE (op) == LTU;

    case CCL2mode:
      return GET_CODE (op) == LEU;

    case CCL3mode:
      return GET_CODE (op) == GEU;

    case CCUmode:
      return GET_CODE (op) == GTU;

    case CCURmode:
      return GET_CODE (op) == LTU;

    case CCSmode:
      return GET_CODE (op) == UNGT;

    case CCSRmode:
      return GET_CODE (op) == UNLT;

    default:
      return 0;
    }
}

/* Return nonzero if OP is a valid comparison operator
   for an SLB condition in mode MODE.  */

int
s390_slb_comparison (rtx op, enum machine_mode mode)
{
  if (mode != VOIDmode && mode != GET_MODE (op))
    return 0;

  while (GET_CODE (op) == ZERO_EXTEND || GET_CODE (op) == SIGN_EXTEND)
    op = XEXP (op, 0);

  if (!COMPARISON_P (op))
    return 0;

  if (GET_CODE (XEXP (op, 0)) != REG
      || REGNO (XEXP (op, 0)) != CC_REGNUM
      || XEXP (op, 1) != const0_rtx)
    return 0;

  switch (GET_MODE (XEXP (op, 0)))
    {
    case CCL1mode:
      return GET_CODE (op) == GEU;

    case CCL2mode:
      return GET_CODE (op) == GTU;

    case CCL3mode:
      return GET_CODE (op) == LTU;

    case CCUmode:
      return GET_CODE (op) == LEU;

    case CCURmode:
      return GET_CODE (op) == GEU;

    case CCSmode:
      return GET_CODE (op) == LE;

    case CCSRmode:
      return GET_CODE (op) == GE;

    default:
      return 0;
    }
}

/* Return branch condition mask to implement a branch
   specified by CODE.  */

static int
s390_branch_condition_mask (rtx code)
{
  const int CC0 = 1 << 3;
  const int CC1 = 1 << 2;
  const int CC2 = 1 << 1;
  const int CC3 = 1 << 0;

  if (GET_CODE (XEXP (code, 0)) != REG
      || REGNO (XEXP (code, 0)) != CC_REGNUM
      || XEXP (code, 1) != const0_rtx)
    abort ();

  switch (GET_MODE (XEXP (code, 0)))
    {
    case CCZmode:
      switch (GET_CODE (code))
        {
        case EQ:        return CC0;
        case NE:        return CC1 | CC2 | CC3;
        default:
          abort ();
        }
      break;

    case CCT1mode:
      switch (GET_CODE (code))
        {
        case EQ:        return CC1;
        case NE:        return CC0 | CC2 | CC3;
        default:
          abort ();
        }
      break;

    case CCT2mode:
      switch (GET_CODE (code))
        {
        case EQ:        return CC2;
        case NE:        return CC0 | CC1 | CC3;
        default:
          abort ();
        }
      break;

    case CCT3mode:
      switch (GET_CODE (code))
        {
        case EQ:        return CC3;
        case NE:        return CC0 | CC1 | CC2;
        default:
          abort ();
        }
      break;

    case CCLmode:
      switch (GET_CODE (code))
        {
        case EQ:        return CC0 | CC2;
        case NE:        return CC1 | CC3;
        default:
          abort ();
        }
      break;

    case CCL1mode:
      switch (GET_CODE (code))
        {
        case LTU:       return CC2 | CC3;  /* carry */
        case GEU:       return CC0 | CC1;  /* no carry */
        default:
          abort ();
        }
      break;

    case CCL2mode:
      switch (GET_CODE (code))
        {
        case GTU:       return CC0 | CC1;  /* borrow */
        case LEU:       return CC2 | CC3;  /* no borrow */
        default:
          abort ();
        }
      break;

    case CCL3mode:
      switch (GET_CODE (code))
        {
        case EQ:        return CC0 | CC2;
        case NE:        return CC1 | CC3;
        case LTU:       return CC1;
        case GTU:       return CC3;
        case LEU:       return CC1 | CC2;
        case GEU:       return CC2 | CC3;
        default:
          abort ();
        }

    case CCUmode:
      switch (GET_CODE (code))
        {
        case EQ:        return CC0;
        case NE:        return CC1 | CC2 | CC3;
        case LTU:       return CC1;
        case GTU:       return CC2;
        case LEU:       return CC0 | CC1;
        case GEU:       return CC0 | CC2;
        default:
          abort ();
        }
      break;

    case CCURmode:
      switch (GET_CODE (code))
        {
        case EQ:        return CC0;
        case NE:        return CC2 | CC1 | CC3;
        case LTU:       return CC2;
        case GTU:       return CC1;
        case LEU:       return CC0 | CC2;
        case GEU:       return CC0 | CC1;
        default:
          abort ();
        }
      break;

    case CCAPmode:
      switch (GET_CODE (code))
        {
        case EQ:        return CC0;
        case NE:        return CC1 | CC2 | CC3;
        case LT:        return CC1 | CC3;
        case GT:        return CC2;
        case LE:        return CC0 | CC1 | CC3;
        case GE:        return CC0 | CC2;
        default:
          abort ();
        }
      break;

    case CCANmode:
      switch (GET_CODE (code))
        {
        case EQ:        return CC0;
        case NE:        return CC1 | CC2 | CC3;
        case LT:        return CC1;
        case GT:        return CC2 | CC3;
        case LE:        return CC0 | CC1;
        case GE:        return CC0 | CC2 | CC3;
        default:
          abort ();
        }
      break;

    case CCSmode:
      switch (GET_CODE (code))
        {
        case EQ:        return CC0;
        case NE:        return CC1 | CC2 | CC3;
        case LT:        return CC1;
        case GT:        return CC2;
        case LE:        return CC0 | CC1;
        case GE:        return CC0 | CC2;
        case UNORDERED: return CC3;
        case ORDERED:   return CC0 | CC1 | CC2;
        case UNEQ:      return CC0 | CC3;
        case UNLT:      return CC1 | CC3;
        case UNGT:      return CC2 | CC3;
        case UNLE:      return CC0 | CC1 | CC3;
        case UNGE:      return CC0 | CC2 | CC3;
        case LTGT:      return CC1 | CC2;
        default:
          abort ();
        }
      break;

    case CCSRmode:
      switch (GET_CODE (code))
        {
        case EQ:        return CC0;
        case NE:        return CC2 | CC1 | CC3;
        case LT:        return CC2;
        case GT:        return CC1;
        case LE:        return CC0 | CC2;
        case GE:        return CC0 | CC1;
        case UNORDERED: return CC3;
        case ORDERED:   return CC0 | CC2 | CC1;
        case UNEQ:      return CC0 | CC3;
        case UNLT:      return CC2 | CC3;
        case UNGT:      return CC1 | CC3;
        case UNLE:      return CC0 | CC2 | CC3;
        case UNGE:      return CC0 | CC1 | CC3;
        case LTGT:      return CC2 | CC1;
        default:
          abort ();
        }
      break;

    default:
      abort ();
    }
}

/* If INV is false, return assembler mnemonic string to implement
   a branch specified by CODE.  If INV is true, return mnemonic
   for the corresponding inverted branch.  */

static const char *
s390_branch_condition_mnemonic (rtx code, int inv)
{
  static const char *const mnemonic[16] =
    {
      NULL, "o", "h", "nle",
      "l", "nhe", "lh", "ne",
      "e", "nlh", "he", "nl",
      "le", "nh", "no", NULL
    };

  int mask = s390_branch_condition_mask (code);

  if (inv)
    mask ^= 15;

  if (mask < 1 || mask > 14)
    abort ();

  return mnemonic[mask];
}

/* Return the part of op which has a value different from def.
   The size of the part is determined by mode.
   Use this function only if you already know that op really
   contains such a part.  */

unsigned HOST_WIDE_INT
s390_extract_part (rtx op, enum machine_mode mode, int def)
{
  unsigned HOST_WIDE_INT value = 0;
  int max_parts = HOST_BITS_PER_WIDE_INT / GET_MODE_BITSIZE (mode);
  int part_bits = GET_MODE_BITSIZE (mode);
  unsigned HOST_WIDE_INT part_mask = (1 << part_bits) - 1;
  int i;

  for (i = 0; i < max_parts; i++)
    {
      if (i == 0)
        value = (unsigned HOST_WIDE_INT) INTVAL (op);
      else
        value >>= part_bits;

      if ((value & part_mask) != (def & part_mask))
        return value & part_mask;
    }

  abort ();
}

/* If OP is an integer constant of mode MODE with exactly one
   part of mode PART_MODE unequal to DEF, return the number of that
   part. Otherwise, return -1.  */

int
s390_single_part (rtx op,
                  enum machine_mode mode,
                  enum machine_mode part_mode,
                  int def)
{
  unsigned HOST_WIDE_INT value = 0;
  int n_parts = GET_MODE_SIZE (mode) / GET_MODE_SIZE (part_mode);
  unsigned HOST_WIDE_INT part_mask = (1 << GET_MODE_BITSIZE (part_mode)) - 1;
  int i, part = -1;

  if (GET_CODE (op) != CONST_INT)
    return -1;

  for (i = 0; i < n_parts; i++)
    {
      if (i == 0)
        value = (unsigned HOST_WIDE_INT) INTVAL (op);
      else
        value >>= GET_MODE_BITSIZE (part_mode);

      if ((value & part_mask) != (def & part_mask))
        {
          if (part != -1)
            return -1;
          else
            part = i;
        }
    }
  return part == -1 ? -1 : n_parts - 1 - part;
}

/* Check whether we can (and want to) split a double-word
   move in mode MODE from SRC to DST into two single-word
   moves, moving the subword FIRST_SUBWORD first.  */

bool
s390_split_ok_p (rtx dst, rtx src, enum machine_mode mode, int first_subword)
{
  /* Floating point registers cannot be split.  */
  if (FP_REG_P (src) || FP_REG_P (dst))
    return false;

  /* We don't need to split if operands are directly accessible.  */
  if (s_operand (src, mode) || s_operand (dst, mode))
    return false;

  /* Non-offsettable memory references cannot be split.  */
  if ((GET_CODE (src) == MEM && !offsettable_memref_p (src))
      || (GET_CODE (dst) == MEM && !offsettable_memref_p (dst)))
    return false;

  /* Moving the first subword must not clobber a register
     needed to move the second subword.  */
  if (register_operand (dst, mode))
    {
      rtx subreg = operand_subword (dst, first_subword, 0, mode);
      if (reg_overlap_mentioned_p (subreg, src))
        return false;
    }

  return true;
}


/* Change optimizations to be performed, depending on the
   optimization level.

   LEVEL is the optimization level specified; 2 if `-O2' is
   specified, 1 if `-O' is specified, and 0 if neither is specified.

   SIZE is nonzero if `-Os' is specified and zero otherwise.  */

void
optimization_options (int level ATTRIBUTE_UNUSED, int size ATTRIBUTE_UNUSED)
{
  /* ??? There are apparently still problems with -fcaller-saves.  */
  flag_caller_saves = 0;

  /* By default, always emit DWARF-2 unwind info.  This allows debugging
     without maintaining a stack frame back-chain.  */
  flag_asynchronous_unwind_tables = 1;
}

void
override_options (void)
{
  int i;
  static struct pta
    {
      const char *const name;           /* processor name or nickname.  */
      const enum processor_type processor;
      const enum processor_flags flags;
    }
  const processor_alias_table[] =
    {
      {"g5", PROCESSOR_9672_G5, PF_IEEE_FLOAT},
      {"g6", PROCESSOR_9672_G6, PF_IEEE_FLOAT},
      {"z900", PROCESSOR_2064_Z900, PF_IEEE_FLOAT | PF_ZARCH},
      {"z990", PROCESSOR_2084_Z990, PF_IEEE_FLOAT | PF_ZARCH
                                    | PF_LONG_DISPLACEMENT},
    };

  int const pta_size = ARRAY_SIZE (processor_alias_table);

  /* Acquire a unique set number for our register saves and restores.  */
  s390_sr_alias_set = new_alias_set ();

  /* Set up function hooks.  */
  init_machine_status = s390_init_machine_status;

  /* Architecture mode defaults according to ABI.  */
  if (!(target_flags_explicit & MASK_ZARCH))
    {
      if (TARGET_64BIT)
        target_flags |= MASK_ZARCH;
      else
        target_flags &= ~MASK_ZARCH;
    }

  /* Determine processor architectural level.  */
  if (!s390_arch_string)
    s390_arch_string = TARGET_ZARCH? "z900" : "g5";

  for (i = 0; i < pta_size; i++)
    if (! strcmp (s390_arch_string, processor_alias_table[i].name))
      {
        s390_arch = processor_alias_table[i].processor;
        s390_arch_flags = processor_alias_table[i].flags;
        break;
      }
  if (i == pta_size)
    error ("Unknown cpu used in -march=%s.", s390_arch_string);

  /* Determine processor to tune for.  */
  if (!s390_tune_string)
    {
      s390_tune = s390_arch;
      s390_tune_flags = s390_arch_flags;
      s390_tune_string = s390_arch_string;
    }
  else
    {
      for (i = 0; i < pta_size; i++)
        if (! strcmp (s390_tune_string, processor_alias_table[i].name))
          {
            s390_tune = processor_alias_table[i].processor;
            s390_tune_flags = processor_alias_table[i].flags;
            break;
          }
      if (i == pta_size)
        error ("Unknown cpu used in -mtune=%s.", s390_tune_string);
    }

  /* Sanity checks.  */
  if (TARGET_ZARCH && !(s390_arch_flags & PF_ZARCH))
    error ("z/Architecture mode not supported on %s.", s390_arch_string);
  if (TARGET_64BIT && !TARGET_ZARCH)
    error ("64-bit ABI not supported in ESA/390 mode.");
}

/* Map for smallest class containing reg regno.  */

const enum reg_class regclass_map[FIRST_PSEUDO_REGISTER] =
{ GENERAL_REGS, ADDR_REGS, ADDR_REGS, ADDR_REGS,
  ADDR_REGS,    ADDR_REGS, ADDR_REGS, ADDR_REGS,
  ADDR_REGS,    ADDR_REGS, ADDR_REGS, ADDR_REGS,
  ADDR_REGS,    ADDR_REGS, ADDR_REGS, ADDR_REGS,
  FP_REGS,      FP_REGS,   FP_REGS,   FP_REGS,
  FP_REGS,      FP_REGS,   FP_REGS,   FP_REGS,
  FP_REGS,      FP_REGS,   FP_REGS,   FP_REGS,
  FP_REGS,      FP_REGS,   FP_REGS,   FP_REGS,
  ADDR_REGS,    NO_REGS,   ADDR_REGS
};

/* Return attribute type of insn.  */

static enum attr_type
s390_safe_attr_type (rtx insn)
{
  if (recog_memoized (insn) >= 0)
    return get_attr_type (insn);
  else
    return TYPE_NONE;
}

/* Return true if OP a (const_int 0) operand.
   OP is the current operation.
   MODE is the current operation mode.  */

int
const0_operand (register rtx op, enum machine_mode mode)
{
  return op == CONST0_RTX (mode);
}

/* Return true if OP is constant.
   OP is the current operation.
   MODE is the current operation mode.  */

int
consttable_operand (rtx op, enum machine_mode mode ATTRIBUTE_UNUSED)
{
  return CONSTANT_P (op);
}

/* Return true if the mode of operand OP matches MODE.
   If MODE is set to VOIDmode, set it to the mode of OP.  */

static int
check_mode (register rtx op, enum machine_mode *mode)
{
  if (*mode == VOIDmode)
      *mode = GET_MODE (op);
  else
  {
    if (GET_MODE (op) != VOIDmode && GET_MODE (op) != *mode)
       return 0;
  }
  return 1;
}

/* Return true if OP a valid operand for the LARL instruction.
   OP is the current operation.
   MODE is the current operation mode.  */

int
larl_operand (register rtx op, enum machine_mode mode)
{
  if (! check_mode (op, &mode))
    return 0;

  /* Allow labels and local symbols.  */
  if (GET_CODE (op) == LABEL_REF)
    return 1;
  if (GET_CODE (op) == SYMBOL_REF)
    return ((SYMBOL_REF_FLAGS (op) & SYMBOL_FLAG_ALIGN1) == 0
            && SYMBOL_REF_TLS_MODEL (op) == 0
            && (!flag_pic || SYMBOL_REF_LOCAL_P (op)));

  /* Everything else must have a CONST, so strip it.  */
  if (GET_CODE (op) != CONST)
    return 0;
  op = XEXP (op, 0);

  /* Allow adding *even* in-range constants.  */
  if (GET_CODE (op) == PLUS)
    {
      if (GET_CODE (XEXP (op, 1)) != CONST_INT
          || (INTVAL (XEXP (op, 1)) & 1) != 0)
        return 0;
#if HOST_BITS_PER_WIDE_INT > 32
      if (INTVAL (XEXP (op, 1)) >= (HOST_WIDE_INT)1 << 32
          || INTVAL (XEXP (op, 1)) < -((HOST_WIDE_INT)1 << 32))
        return 0;
#endif
      op = XEXP (op, 0);
    }

  /* Labels and local symbols allowed here as well.  */
  if (GET_CODE (op) == LABEL_REF)
    return 1;
  if (GET_CODE (op) == SYMBOL_REF)
    return ((SYMBOL_REF_FLAGS (op) & SYMBOL_FLAG_ALIGN1) == 0
            && SYMBOL_REF_TLS_MODEL (op) == 0
            && (!flag_pic || SYMBOL_REF_LOCAL_P (op)));

  /* Now we must have a @GOTENT offset or @PLT stub
     or an @INDNTPOFF TLS offset.  */
  if (GET_CODE (op) == UNSPEC
      && XINT (op, 1) == UNSPEC_GOTENT)
    return 1;
  if (GET_CODE (op) == UNSPEC
      && XINT (op, 1) == UNSPEC_PLT)
    return 1;
  if (GET_CODE (op) == UNSPEC
      && XINT (op, 1) == UNSPEC_INDNTPOFF)
    return 1;

  return 0;
}

/* Helper routine to implement s_operand and s_imm_operand.
   OP is the current operation.
   MODE is the current operation mode.
   ALLOW_IMMEDIATE specifies whether immediate operands should
   be accepted or not.  */

static int
general_s_operand (register rtx op, enum machine_mode mode,
                   int allow_immediate)
{
  struct s390_address addr;

  /* Call general_operand first, so that we don't have to
     check for many special cases.  */
  if (!general_operand (op, mode))
    return 0;

  /* Just like memory_operand, allow (subreg (mem ...))
     after reload.  */
  if (reload_completed
      && GET_CODE (op) == SUBREG
      && GET_CODE (SUBREG_REG (op)) == MEM)
    op = SUBREG_REG (op);

  switch (GET_CODE (op))
    {
      /* Constants are OK as s-operand if ALLOW_IMMEDIATE
         is true and we are still before reload.  */
      case CONST_INT:
      case CONST_DOUBLE:
        if (!allow_immediate || reload_completed)
          return 0;
        return 1;

      /* Memory operands are OK unless they already use an
         index register.  */
      case MEM:
        if (!s390_decompose_address (XEXP (op, 0), &addr))
          return 0;
        if (addr.indx)
          return 0;
        /* Do not allow literal pool references unless ALLOW_IMMEDIATE
           is true.  This prevents compares between two literal pool
           entries from being accepted.  */
        if (!allow_immediate
            && addr.base && REGNO (addr.base) == BASE_REGISTER)
          return 0;
        return 1;

      default:
        break;
    }

  return 0;
}

/* Return true if OP is a valid S-type operand.
   OP is the current operation.
   MODE is the current operation mode.  */

int
s_operand (register rtx op, enum machine_mode mode)
{
  return general_s_operand (op, mode, 0);
}

/* Return true if OP is a valid S-type operand or an immediate
   operand that can be addressed as S-type operand by forcing
   it into the literal pool.
   OP is the current operation.
   MODE is the current operation mode.  */

int
s_imm_operand (register rtx op, enum machine_mode mode)
{
  return general_s_operand (op, mode, 1);
}

/* Return true if OP a valid shift count operand.
   OP is the current operation.
   MODE is the current operation mode.  */

int
shift_count_operand (rtx op, enum machine_mode mode)
{
  HOST_WIDE_INT offset = 0;

  if (! check_mode (op, &mode))
    return 0;

  /* We can have an integer constant, an address register,
     or a sum of the two.  Note that reload already checks
     that any register present is an address register, so
     we just check for any register here.  */
  if (GET_CODE (op) == CONST_INT)
    {
      offset = INTVAL (op);
      op = NULL_RTX;
    }
  if (op && GET_CODE (op) == PLUS && GET_CODE (XEXP (op, 1)) == CONST_INT)
    {
      offset = INTVAL (XEXP (op, 1));
      op = XEXP (op, 0);
    }
  while (op && GET_CODE (op) == SUBREG)
    op = SUBREG_REG (op);
  if (op && GET_CODE (op) != REG)
    return 0;

  /* Unfortunately we have to reject constants that are invalid
     for an address, or else reload will get confused.  */
  if (!DISP_IN_RANGE (offset))
    return 0;

  return 1;
}

/* Return true if DISP is a valid short displacement.  */

static int
s390_short_displacement (rtx disp)
{
  /* No displacement is OK.  */
  if (!disp)
    return 1;

  /* Integer displacement in range.  */
  if (GET_CODE (disp) == CONST_INT)
    return INTVAL (disp) >= 0 && INTVAL (disp) < 4096;

  /* GOT offset is not OK, the GOT can be large.  */
  if (GET_CODE (disp) == CONST
      && GET_CODE (XEXP (disp, 0)) == UNSPEC
      && XINT (XEXP (disp, 0), 1) == UNSPEC_GOT)
    return 0;

  /* All other symbolic constants are literal pool references,
     which are OK as the literal pool must be small.  */
  if (GET_CODE (disp) == CONST)
    return 1;

  return 0;
}

/* Return true if OP is a valid operand for a C constraint.  */

int
s390_extra_constraint_str (rtx op, int c, const char * str)
{
  struct s390_address addr;

  if (c != str[0])
    abort ();

  switch (c)
    {
    case 'Q':
      if (GET_CODE (op) != MEM)
        return 0;
      if (!s390_decompose_address (XEXP (op, 0), &addr))
        return 0;
      if (addr.indx)
        return 0;

      if (TARGET_LONG_DISPLACEMENT)
        {
          if (!s390_short_displacement (addr.disp))
            return 0;
        }
      break;

    case 'R':
      if (GET_CODE (op) != MEM)
        return 0;

      if (TARGET_LONG_DISPLACEMENT)
        {
          if (!s390_decompose_address (XEXP (op, 0), &addr))
            return 0;
          if (!s390_short_displacement (addr.disp))
            return 0;
        }
      break;

    case 'S':
      if (!TARGET_LONG_DISPLACEMENT)
        return 0;
      if (GET_CODE (op) != MEM)
        return 0;
      if (!s390_decompose_address (XEXP (op, 0), &addr))
        return 0;
      if (addr.indx)
        return 0;
      if (s390_short_displacement (addr.disp))
        return 0;
      break;

    case 'T':
      if (!TARGET_LONG_DISPLACEMENT)
        return 0;
      if (GET_CODE (op) != MEM)
        return 0;
      /* Any invalid address here will be fixed up by reload,
         so accept it for the most generic constraint.  */
      if (s390_decompose_address (XEXP (op, 0), &addr)
          && s390_short_displacement (addr.disp))
        return 0;
      break;

    case 'U':
      if (TARGET_LONG_DISPLACEMENT)
        {
          if (!s390_decompose_address (op, &addr))
            return 0;
          if (!s390_short_displacement (addr.disp))
            return 0;
        }
      break;

    case 'W':
      if (!TARGET_LONG_DISPLACEMENT)
        return 0;
      /* Any invalid address here will be fixed up by reload,
         so accept it for the most generic constraint.  */
      if (s390_decompose_address (op, &addr)
          && s390_short_displacement (addr.disp))
        return 0;
      break;

    case 'Y':
      return shift_count_operand (op, VOIDmode);

    default:
      return 0;
    }

  return 1;
}

/* Return true if VALUE matches the constraint STR.  */

int
s390_const_ok_for_constraint_p (HOST_WIDE_INT value,
                                int c,
                                const char * str)
{
  enum machine_mode mode, part_mode;
  int def;
  unsigned char part;

  if (c != str[0])
    abort ();

  switch (str[0])
    {
    case 'I':
      return (unsigned int)value < 256;

    case 'J':
      return (unsigned int)value < 4096;

    case 'K':
      return value >= -32768 && value < 32768;

    case 'L':
      return (TARGET_LONG_DISPLACEMENT ?
              (value >= -524288 && value <= 524287)
              : (value >= 0 && value <= 4095));
    case 'M':
      return value == 2147483647;

    case 'N':
      part = str[1] - '0';

      switch (str[2])
        {
        case 'H': part_mode = HImode; break;
        case 'Q': part_mode = QImode; break;
        default:  return 0;
        }

      switch (str[3])
        {
        case 'H': mode = HImode; break;
        case 'S': mode = SImode; break;
        case 'D': mode = DImode; break;
        default: return 0;
        }

      switch (str[4])
        {
        case '0': def = 0;  break;
        case 'F': def = -1; break;
        default: return 0;
        }

      if (GET_MODE_SIZE (mode) <= GET_MODE_SIZE (part_mode))
        return 0;

      if (s390_single_part (GEN_INT (value), mode, part_mode, def) != part)
        return 0;

      break;

    default:
      return 0;
    }

  return 1;
}

/* Compute a (partial) cost for rtx X.  Return true if the complete
   cost has been computed, and false if subexpressions should be
   scanned.  In either case, *TOTAL contains the cost result.  */

static bool
s390_rtx_costs (rtx x, int code, int outer_code, int *total)
{
  switch (code)
    {
    case CONST:
      if (GET_CODE (XEXP (x, 0)) == MINUS
          && GET_CODE (XEXP (XEXP (x, 0), 1)) != CONST_INT)
        *total = 1000;
      else
        *total = 0;
      return true;

    case CONST_INT:
      /* Force_const_mem does not work out of reload, because the
         saveable_obstack is set to reload_obstack, which does not
         live long enough.  Because of this we cannot use force_const_mem
         in addsi3.  This leads to problems with gen_add2_insn with a
         constant greater than a short. Because of that we give an
         addition of greater constants a cost of 3 (reload1.c 10096).  */
      /* ??? saveable_obstack no longer exists.  */
      if (outer_code == PLUS
          && (INTVAL (x) > 32767 || INTVAL (x) < -32768))
        *total = COSTS_N_INSNS (3);
      else
        *total = 0;
      return true;

    case LABEL_REF:
    case SYMBOL_REF:
    case CONST_DOUBLE:
      *total = 0;
      return true;

    case ASHIFT:
    case ASHIFTRT:
    case LSHIFTRT:
    case PLUS:
    case AND:
    case IOR:
    case XOR:
    case MINUS:
    case NEG:
    case NOT:
      *total = COSTS_N_INSNS (1);
      return true;

    case MULT:
      if (GET_MODE (XEXP (x, 0)) == DImode)
        *total = COSTS_N_INSNS (40);
      else
        *total = COSTS_N_INSNS (7);
      return true;

    case DIV:
    case UDIV:
    case MOD:
    case UMOD:
      *total = COSTS_N_INSNS (33);
      return true;

    default:
      return false;
    }
}

/* Return the cost of an address rtx ADDR.  */

static int
s390_address_cost (rtx addr)
{
  struct s390_address ad;
  if (!s390_decompose_address (addr, &ad))
    return 1000;

  return ad.indx? COSTS_N_INSNS (1) + 1 : COSTS_N_INSNS (1);
}

/* Return true if OP is a valid operand for the BRAS instruction.
   OP is the current operation.
   MODE is the current operation mode.  */

int
bras_sym_operand (register rtx op, enum machine_mode mode ATTRIBUTE_UNUSED)
{
  register enum rtx_code code = GET_CODE (op);

  /* Allow SYMBOL_REFs.  */
  if (code == SYMBOL_REF)
    return 1;

  /* Allow @PLT stubs.  */
  if (code == CONST
      && GET_CODE (XEXP (op, 0)) == UNSPEC
      && XINT (XEXP (op, 0), 1) == UNSPEC_PLT)
    return 1;
  return 0;
}

/* If OP is a SYMBOL_REF of a thread-local symbol, return its TLS mode,
   otherwise return 0.  */

int
tls_symbolic_operand (register rtx op)
{
  if (GET_CODE (op) != SYMBOL_REF)
    return 0;
  return SYMBOL_REF_TLS_MODEL (op);
}
\f
/* Return true if OP is a load multiple operation.  It is known to be a
   PARALLEL and the first section will be tested.
   OP is the current operation.
   MODE is the current operation mode.  */

int
load_multiple_operation (rtx op, enum machine_mode mode ATTRIBUTE_UNUSED)
{
  enum machine_mode elt_mode;
  int count = XVECLEN (op, 0);
  unsigned int dest_regno;
  rtx src_addr;
  int i, off;


  /* Perform a quick check so we don't blow up below.  */
  if (count <= 1
      || GET_CODE (XVECEXP (op, 0, 0)) != SET
      || GET_CODE (SET_DEST (XVECEXP (op, 0, 0))) != REG
      || GET_CODE (SET_SRC (XVECEXP (op, 0, 0))) != MEM)
    return 0;

  dest_regno = REGNO (SET_DEST (XVECEXP (op, 0, 0)));
  src_addr = XEXP (SET_SRC (XVECEXP (op, 0, 0)), 0);
  elt_mode = GET_MODE (SET_DEST (XVECEXP (op, 0, 0)));

  /* Check, is base, or base + displacement.  */

  if (GET_CODE (src_addr) == REG)
    off = 0;
  else if (GET_CODE (src_addr) == PLUS
           && GET_CODE (XEXP (src_addr, 0)) == REG
           && GET_CODE (XEXP (src_addr, 1)) == CONST_INT)
    {
      off = INTVAL (XEXP (src_addr, 1));
      src_addr = XEXP (src_addr, 0);
    }
  else
    return 0;

  if (src_addr == frame_pointer_rtx || src_addr == arg_pointer_rtx)
    return 0;

  for (i = 1; i < count; i++)
    {
      rtx elt = XVECEXP (op, 0, i);

      if (GET_CODE (elt) != SET
          || GET_CODE (SET_DEST (elt)) != REG
          || GET_MODE (SET_DEST (elt)) != elt_mode
          || REGNO (SET_DEST (elt)) != dest_regno + i
          || GET_CODE (SET_SRC (elt)) != MEM
          || GET_MODE (SET_SRC (elt)) != elt_mode
          || GET_CODE (XEXP (SET_SRC (elt), 0)) != PLUS
          || ! rtx_equal_p (XEXP (XEXP (SET_SRC (elt), 0), 0), src_addr)
          || GET_CODE (XEXP (XEXP (SET_SRC (elt), 0), 1)) != CONST_INT
          || INTVAL (XEXP (XEXP (SET_SRC (elt), 0), 1))
             != off + i * GET_MODE_SIZE (elt_mode))
        return 0;
    }

  return 1;
}

/* Return true if OP is a store multiple operation.  It is known to be a
   PARALLEL and the first section will be tested.
   OP is the current operation.
   MODE is the current operation mode.  */

int
store_multiple_operation (rtx op, enum machine_mode mode ATTRIBUTE_UNUSED)
{
  enum machine_mode elt_mode;
  int count = XVECLEN (op, 0);
  unsigned int src_regno;
  rtx dest_addr;
  int i, off;

  /* Perform a quick check so we don't blow up below.  */
  if (count <= 1
      || GET_CODE (XVECEXP (op, 0, 0)) != SET
      || GET_CODE (SET_DEST (XVECEXP (op, 0, 0))) != MEM
      || GET_CODE (SET_SRC (XVECEXP (op, 0, 0))) != REG)
    return 0;

  src_regno = REGNO (SET_SRC (XVECEXP (op, 0, 0)));
  dest_addr = XEXP (SET_DEST (XVECEXP (op, 0, 0)), 0);
  elt_mode = GET_MODE (SET_SRC (XVECEXP (op, 0, 0)));

  /* Check, is base, or base + displacement.  */

  if (GET_CODE (dest_addr) == REG)
    off = 0;
  else if (GET_CODE (dest_addr) == PLUS
           && GET_CODE (XEXP (dest_addr, 0)) == REG
           && GET_CODE (XEXP (dest_addr, 1)) == CONST_INT)
    {
      off = INTVAL (XEXP (dest_addr, 1));
      dest_addr = XEXP (dest_addr, 0);
    }
  else
    return 0;

  if (dest_addr == frame_pointer_rtx || dest_addr == arg_pointer_rtx)
    return 0;

  for (i = 1; i < count; i++)
    {
      rtx elt = XVECEXP (op, 0, i);

      if (GET_CODE (elt) != SET
          || GET_CODE (SET_SRC (elt)) != REG
          || GET_MODE (SET_SRC (elt)) != elt_mode
          || REGNO (SET_SRC (elt)) != src_regno + i
          || GET_CODE (SET_DEST (elt)) != MEM
          || GET_MODE (SET_DEST (elt)) != elt_mode
          || GET_CODE (XEXP (SET_DEST (elt), 0)) != PLUS
          || ! rtx_equal_p (XEXP (XEXP (SET_DEST (elt), 0), 0), dest_addr)
          || GET_CODE (XEXP (XEXP (SET_DEST (elt), 0), 1)) != CONST_INT
          || INTVAL (XEXP (XEXP (SET_DEST (elt), 0), 1))
             != off + i * GET_MODE_SIZE (elt_mode))
        return 0;
    }
  return 1;
}


/* Return true if OP contains a symbol reference */

int
symbolic_reference_mentioned_p (rtx op)
{
  register const char *fmt;
  register int i;

  if (GET_CODE (op) == SYMBOL_REF || GET_CODE (op) == LABEL_REF)
    return 1;

  fmt = GET_RTX_FORMAT (GET_CODE (op));
  for (i = GET_RTX_LENGTH (GET_CODE (op)) - 1; i >= 0; i--)
    {
      if (fmt[i] == 'E')
        {
          register int j;

          for (j = XVECLEN (op, i) - 1; j >= 0; j--)
            if (symbolic_reference_mentioned_p (XVECEXP (op, i, j)))
              return 1;
        }

      else if (fmt[i] == 'e' && symbolic_reference_mentioned_p (XEXP (op, i)))
        return 1;
    }

  return 0;
}

/* Return true if OP contains a reference to a thread-local symbol.  */

int
tls_symbolic_reference_mentioned_p (rtx op)
{
  register const char *fmt;
  register int i;

  if (GET_CODE (op) == SYMBOL_REF)
    return tls_symbolic_operand (op);

  fmt = GET_RTX_FORMAT (GET_CODE (op));
  for (i = GET_RTX_LENGTH (GET_CODE (op)) - 1; i >= 0; i--)
    {
      if (fmt[i] == 'E')
        {
          register int j;

          for (j = XVECLEN (op, i) - 1; j >= 0; j--)
            if (tls_symbolic_reference_mentioned_p (XVECEXP (op, i, j)))
              return 1;
        }

      else if (fmt[i] == 'e' && tls_symbolic_reference_mentioned_p (XEXP (op, i)))
        return 1;
    }

  return 0;
}


/* Return true if OP is a legitimate general operand when
   generating PIC code.  It is given that flag_pic is on
   and that OP satisfies CONSTANT_P or is a CONST_DOUBLE.  */

int
legitimate_pic_operand_p (register rtx op)
{
  /* Accept all non-symbolic constants.  */
  if (!SYMBOLIC_CONST (op))
    return 1;

  /* Reject everything else; must be handled
     via emit_symbolic_move.  */
  return 0;
}

/* Returns true if the constant value OP is a legitimate general operand.
   It is given that OP satisfies CONSTANT_P or is a CONST_DOUBLE.  */

int
legitimate_constant_p (register rtx op)
{
  /* Accept all non-symbolic constants.  */
  if (!SYMBOLIC_CONST (op))
    return 1;

  /* Accept immediate LARL operands.  */
  if (TARGET_CPU_ZARCH && larl_operand (op, VOIDmode))
    return 1;

  /* Thread-local symbols are never legal constants.  This is
     so that emit_call knows that computing such addresses
     might require a function call.  */
  if (TLS_SYMBOLIC_CONST (op))
    return 0;

  /* In the PIC case, symbolic constants must *not* be
     forced into the literal pool.  We accept them here,
     so that they will be handled by emit_symbolic_move.  */
  if (flag_pic)
    return 1;

  /* All remaining non-PIC symbolic constants are
     forced into the literal pool.  */
  return 0;
}

/* Determine if it's legal to put X into the constant pool.  This
   is not possible if X contains the address of a symbol that is
   not constant (TLS) or not known at final link time (PIC).  */

static bool
s390_cannot_force_const_mem (rtx x)
{
  switch (GET_CODE (x))
    {
    case CONST_INT:
    case CONST_DOUBLE:
      /* Accept all non-symbolic constants.  */
      return false;

    case LABEL_REF:
      /* Labels are OK iff we are non-PIC.  */
      return flag_pic != 0;

    case SYMBOL_REF:
      /* 'Naked' TLS symbol references are never OK,
         non-TLS symbols are OK iff we are non-PIC.  */
      if (tls_symbolic_operand (x))
        return true;
      else
        return flag_pic != 0;

    case CONST:
      return s390_cannot_force_const_mem (XEXP (x, 0));
    case PLUS:
    case MINUS:
      return s390_cannot_force_const_mem (XEXP (x, 0))
             || s390_cannot_force_const_mem (XEXP (x, 1));

    case UNSPEC:
      switch (XINT (x, 1))
        {
        /* Only lt-relative or GOT-relative UNSPECs are OK.  */
        case UNSPEC_LTREL_OFFSET:
        case UNSPEC_GOT:
        case UNSPEC_GOTOFF:
        case UNSPEC_PLTOFF:
        case UNSPEC_TLSGD:
        case UNSPEC_TLSLDM:
        case UNSPEC_NTPOFF:
        case UNSPEC_DTPOFF:
        case UNSPEC_GOTNTPOFF:
        case UNSPEC_INDNTPOFF:
          return false;

        default:
          return true;
        }
      break;

    default:
      abort ();
    }
}

/* Returns true if the constant value OP is a legitimate general
   operand during and after reload.  The difference to
   legitimate_constant_p is that this function will not accept
   a constant that would need to be forced to the literal pool
   before it can be used as operand.  */

int
legitimate_reload_constant_p (register rtx op)
{
  /* Accept la(y) operands.  */
  if (GET_CODE (op) == CONST_INT
      && DISP_IN_RANGE (INTVAL (op)))
    return 1;

  /* Accept l(g)hi operands.  */
  if (GET_CODE (op) == CONST_INT
      && CONST_OK_FOR_CONSTRAINT_P (INTVAL (op), 'K', "K"))
    return 1;

  /* Accept lliXX operands.  */
  if (TARGET_ZARCH
      && s390_single_part (op, DImode, HImode, 0) >= 0)
  return 1;

  /* Accept larl operands.  */
  if (TARGET_CPU_ZARCH
      && larl_operand (op, VOIDmode))
    return 1;

  /* Everything else cannot be handled without reload.  */
  return 0;
}

/* Given an rtx OP being reloaded into a reg required to be in class CLASS,
   return the class of reg to actually use.  */

enum reg_class
s390_preferred_reload_class (rtx op, enum reg_class class)
{
  /* This can happen if a floating point constant is being
     reloaded into an integer register.  Leave well alone.  */
  if (GET_MODE_CLASS (GET_MODE (op)) == MODE_FLOAT
      && class != FP_REGS)
    return class;

  switch (GET_CODE (op))
    {
      /* Constants we cannot reload must be forced into the
         literal pool.  */

      case CONST_DOUBLE:
      case CONST_INT:
        if (legitimate_reload_constant_p (op))
          return class;
        else
          return NO_REGS;

      /* If a symbolic constant or a PLUS is reloaded,
         it is most likely being used as an address, so
         prefer ADDR_REGS.  If 'class' is not a superset
         of ADDR_REGS, e.g. FP_REGS, reject this reload.  */
      case PLUS:
      case LABEL_REF:
      case SYMBOL_REF:
      case CONST:
        if (reg_class_subset_p (ADDR_REGS, class))
          return ADDR_REGS;
        else
          return NO_REGS;

      default:
        break;
    }

  return class;
}

/* Return the register class of a scratch register needed to
   load IN into a register of class CLASS in MODE.

   We need a temporary when loading a PLUS expression which
   is not a legitimate operand of the LOAD ADDRESS instruction.  */

enum reg_class
s390_secondary_input_reload_class (enum reg_class class ATTRIBUTE_UNUSED,
                                   enum machine_mode mode, rtx in)
{
  if (s390_plus_operand (in, mode))
    return ADDR_REGS;

  return NO_REGS;
}

/* Return the register class of a scratch register needed to
   store a register of class CLASS in MODE into OUT:

   We need a temporary when storing a double-word to a
   non-offsettable memory address.  */

enum reg_class
s390_secondary_output_reload_class (enum reg_class class,
                                    enum machine_mode mode, rtx out)
{
  if ((TARGET_64BIT ? mode == TImode
                    : (mode == DImode || mode == DFmode))
      && reg_classes_intersect_p (GENERAL_REGS, class)
      && GET_CODE (out) == MEM
      && !offsettable_memref_p (out)
      && !s_operand (out, VOIDmode))
    return ADDR_REGS;

  return NO_REGS;
}

/* Return true if OP is a PLUS that is not a legitimate
   operand for the LA instruction.
   OP is the current operation.
   MODE is the current operation mode.  */

int
s390_plus_operand (register rtx op, enum machine_mode mode)
{
  if (!check_mode (op, &mode) || mode != Pmode)
    return FALSE;

  if (GET_CODE (op) != PLUS)
    return FALSE;

  if (legitimate_la_operand_p (op))
    return FALSE;

  return TRUE;
}

/* Generate code to load SRC, which is PLUS that is not a
   legitimate operand for the LA instruction, into TARGET.
   SCRATCH may be used as scratch register.  */

void
s390_expand_plus_operand (register rtx target, register rtx src,
                          register rtx scratch)
{
  rtx sum1, sum2;
  struct s390_address ad;

  /* src must be a PLUS; get its two operands.  */
  if (GET_CODE (src) != PLUS || GET_MODE (src) != Pmode)
    abort ();

  /* Check if any of the two operands is already scheduled
     for replacement by reload.  This can happen e.g. when
     float registers occur in an address.  */
  sum1 = find_replacement (&XEXP (src, 0));
  sum2 = find_replacement (&XEXP (src, 1));
  src = gen_rtx_PLUS (Pmode, sum1, sum2);

  /* If the address is already strictly valid, there's nothing to do.  */
  if (!s390_decompose_address (src, &ad)
      || (ad.base && !REG_OK_FOR_BASE_STRICT_P (ad.base))
      || (ad.indx && !REG_OK_FOR_INDEX_STRICT_P (ad.indx)))
    {
      /* Otherwise, one of the operands cannot be an address register;
         we reload its value into the scratch register.  */
      if (true_regnum (sum1) < 1 || true_regnum (sum1) > 15)
        {
          emit_move_insn (scratch, sum1);
          sum1 = scratch;
        }
      if (true_regnum (sum2) < 1 || true_regnum (sum2) > 15)
        {
          emit_move_insn (scratch, sum2);
          sum2 = scratch;
        }

      /* According to the way these invalid addresses are generated
         in reload.c, it should never happen (at least on s390) that
         *neither* of the PLUS components, after find_replacements
         was applied, is an address register.  */
      if (sum1 == scratch && sum2 == scratch)
        {
          debug_rtx (src);
          abort ();
        }

      src = gen_rtx_PLUS (Pmode, sum1, sum2);
    }

  /* Emit the LOAD ADDRESS pattern.  Note that reload of PLUS
     is only ever performed on addresses, so we can mark the
     sum as legitimate for LA in any case.  */
  s390_load_address (target, src);
}


/* Decompose a RTL expression ADDR for a memory address into
   its components, returned in OUT.

   Returns 0 if ADDR is not a valid memory address, nonzero
   otherwise.  If OUT is NULL, don't return the components,
   but check for validity only.

   Note: Only addresses in canonical form are recognized.
   LEGITIMIZE_ADDRESS should convert non-canonical forms to the
   canonical form so that they will be recognized.  */

static int
s390_decompose_address (register rtx addr, struct s390_address *out)
{
  HOST_WIDE_INT offset = 0;
  rtx base = NULL_RTX;
  rtx indx = NULL_RTX;
  rtx disp = NULL_RTX;
  rtx orig_disp;
  int pointer = FALSE;
  int base_ptr = FALSE;
  int indx_ptr = FALSE;

  /* Decompose address into base + index + displacement.  */

  if (GET_CODE (addr) == REG || GET_CODE (addr) == UNSPEC)
    base = addr;

  else if (GET_CODE (addr) == PLUS)
    {
      rtx op0 = XEXP (addr, 0);
      rtx op1 = XEXP (addr, 1);
      enum rtx_code code0 = GET_CODE (op0);
      enum rtx_code code1 = GET_CODE (op1);

      if (code0 == REG || code0 == UNSPEC)
        {
          if (code1 == REG || code1 == UNSPEC)
            {
              indx = op0;       /* index + base */
              base = op1;
            }

          else
            {
              base = op0;       /* base + displacement */
              disp = op1;
            }
        }

      else if (code0 == PLUS)
        {
          indx = XEXP (op0, 0); /* index + base + disp */
          base = XEXP (op0, 1);
          disp = op1;
        }

      else
        {
          return FALSE;
        }
    }

  else
    disp = addr;                /* displacement */

  /* Extract integer part of displacement.  */
  orig_disp = disp;
  if (disp)
    {
      if (GET_CODE (disp) == CONST_INT)
        {
          offset = INTVAL (disp);
          disp = NULL_RTX;
        }
      else if (GET_CODE (disp) == CONST
               && GET_CODE (XEXP (disp, 0)) == PLUS
               && GET_CODE (XEXP (XEXP (disp, 0), 1)) == CONST_INT)
        {
          offset = INTVAL (XEXP (XEXP (disp, 0), 1));
          disp = XEXP (XEXP (disp, 0), 0);
        }
    }

  /* Strip off CONST here to avoid special case tests later.  */
  if (disp && GET_CODE (disp) == CONST)
    disp = XEXP (disp, 0);

  /* We can convert literal pool addresses to
     displacements by basing them off the base register.  */
  if (disp && GET_CODE (disp) == SYMBOL_REF && CONSTANT_POOL_ADDRESS_P (disp))
    {
      /* Either base or index must be free to hold the base register.  */
      if (!base)
        base = gen_rtx_REG (Pmode, BASE_REGISTER);
      else if (!indx)
        indx = gen_rtx_REG (Pmode, BASE_REGISTER);
      else
        return FALSE;

      /* Mark up the displacement.  */
      disp = gen_rtx_UNSPEC (Pmode, gen_rtvec (1, disp),
                             UNSPEC_LTREL_OFFSET);
    }

  /* Validate base register.  */
  if (base)
    {
      if (GET_CODE (base) == UNSPEC)
        switch (XINT (base, 1))
          {
          case UNSPEC_LTREF:
            if (!disp)
              disp = gen_rtx_UNSPEC (Pmode, 
                                     gen_rtvec (1, XVECEXP (base, 0, 0)),
                                     UNSPEC_LTREL_OFFSET);
            else
              return FALSE;

            base = gen_rtx_REG (Pmode, BASE_REGISTER);
            break;

          case UNSPEC_LTREL_BASE:
            base = gen_rtx_REG (Pmode, BASE_REGISTER);
            break;

          default:
            return FALSE;
          }

      if (GET_CODE (base) != REG || GET_MODE (base) != Pmode)
        return FALSE;

      if (REGNO (base) == BASE_REGISTER
          || REGNO (base) == STACK_POINTER_REGNUM
          || REGNO (base) == FRAME_POINTER_REGNUM
          || ((reload_completed || reload_in_progress)
              && frame_pointer_needed
              && REGNO (base) == HARD_FRAME_POINTER_REGNUM)
          || REGNO (base) == ARG_POINTER_REGNUM
          || (flag_pic
              && REGNO (base) == PIC_OFFSET_TABLE_REGNUM))
        pointer = base_ptr = TRUE;
    }

  /* Validate index register.  */
  if (indx)
    {
      if (GET_CODE (indx) == UNSPEC)
        switch (XINT (indx, 1))
          {
          case UNSPEC_LTREF:
            if (!disp)
              disp = gen_rtx_UNSPEC (Pmode, 
                                     gen_rtvec (1, XVECEXP (indx, 0, 0)),
                                     UNSPEC_LTREL_OFFSET);
            else
              return FALSE;

            indx = gen_rtx_REG (Pmode, BASE_REGISTER);
            break;

          case UNSPEC_LTREL_BASE:
            indx = gen_rtx_REG (Pmode, BASE_REGISTER);
            break;

          default:
            return FALSE;
          }

      if (GET_CODE (indx) != REG || GET_MODE (indx) != Pmode)
        return FALSE;

      if (REGNO (indx) == BASE_REGISTER
          || REGNO (indx) == STACK_POINTER_REGNUM
          || REGNO (indx) == FRAME_POINTER_REGNUM
          || ((reload_completed || reload_in_progress)
              && frame_pointer_needed
              && REGNO (indx) == HARD_FRAME_POINTER_REGNUM)
          || REGNO (indx) == ARG_POINTER_REGNUM
          || (flag_pic
              && REGNO (indx) == PIC_OFFSET_TABLE_REGNUM))
        pointer = indx_ptr = TRUE;
    }

  /* Prefer to use pointer as base, not index.  */
  if (base && indx && !base_ptr
      && (indx_ptr || (!REG_POINTER (base) && REG_POINTER (indx))))
    {
      rtx tmp = base;
      base = indx;
      indx = tmp;
    }

  /* Validate displacement.  */
  if (!disp)
    {
      /* If the argument pointer is involved, the displacement will change
         later anyway as the argument pointer gets eliminated.  This could
         make a valid displacement invalid, but it is more likely to make
         an invalid displacement valid, because we sometimes access the
         register save area via negative offsets to the arg pointer.
         Thus we don't check the displacement for validity here.  If after
         elimination the displacement turns out to be invalid after all,
         this is fixed up by reload in any case.  */
      if (base != arg_pointer_rtx && indx != arg_pointer_rtx)
        if (!DISP_IN_RANGE (offset))
          return FALSE;
    }
  else
    {
      /* All the special cases are pointers.  */
      pointer = TRUE;

      /* In the small-PIC case, the linker converts @GOT
         and @GOTNTPOFF offsets to possible displacements.  */
      if (GET_CODE (disp) == UNSPEC
          && (XINT (disp, 1) == UNSPEC_GOT
              || XINT (disp, 1) == UNSPEC_GOTNTPOFF)
          && offset == 0
          && flag_pic == 1)
        {
          ;
        }

      /* Accept chunkified literal pool symbol references.  */
      else if (GET_CODE (disp) == MINUS
               && GET_CODE (XEXP (disp, 0)) == LABEL_REF
               && GET_CODE (XEXP (disp, 1)) == LABEL_REF)
        {
          ;
        }

      /* Accept literal pool references.  */
      else if (GET_CODE (disp) == UNSPEC
               && XINT (disp, 1) == UNSPEC_LTREL_OFFSET)
        {
          orig_disp = gen_rtx_CONST (Pmode, disp);
          if (offset)
            {
              /* If we have an offset, make sure it does not
                 exceed the size of the constant pool entry.  */
              rtx sym = XVECEXP (disp, 0, 0);
              if (offset >= GET_MODE_SIZE (get_pool_mode (sym)))
                return FALSE;

              orig_disp = plus_constant (orig_disp, offset);
            }
        }

      else
        return FALSE;
    }

  if (!base && !indx)
    pointer = TRUE;

  if (out)
    {
      out->base = base;
      out->indx = indx;
      out->disp = orig_disp;
      out->pointer = pointer;
    }

  return TRUE;
}

/* Return nonzero if ADDR is a valid memory address.
   STRICT specifies whether strict register checking applies.  */

int
legitimate_address_p (enum machine_mode mode ATTRIBUTE_UNUSED,
                      register rtx addr, int strict)
{
  struct s390_address ad;
  if (!s390_decompose_address (addr, &ad))
    return FALSE;

  if (strict)
    {
      if (ad.base && !REG_OK_FOR_BASE_STRICT_P (ad.base))
        return FALSE;
      if (ad.indx && !REG_OK_FOR_INDEX_STRICT_P (ad.indx))
        return FALSE;
    }
  else
    {
      if (ad.base && !REG_OK_FOR_BASE_NONSTRICT_P (ad.base))
        return FALSE;
      if (ad.indx && !REG_OK_FOR_INDEX_NONSTRICT_P (ad.indx))
        return FALSE;
    }

  return TRUE;
}

/* Return 1 if OP is a valid operand for the LA instruction.
   In 31-bit, we need to prove that the result is used as an
   address, as LA performs only a 31-bit addition.  */

int
legitimate_la_operand_p (register rtx op)
{
  struct s390_address addr;
  if (!s390_decompose_address (op, &addr))
    return FALSE;

  if (TARGET_64BIT || addr.pointer)
    return TRUE;

  return FALSE;
}

/* Return 1 if OP is a valid operand for the LA instruction,
   and we prefer to use LA over addition to compute it.  */

int
preferred_la_operand_p (register rtx op)
{
  struct s390_address addr;
  if (!s390_decompose_address (op, &addr))
    return FALSE;

  if (!TARGET_64BIT && !addr.pointer)
    return FALSE;

  if (addr.pointer)
    return TRUE;

  if ((addr.base && REG_P (addr.base) && REG_POINTER (addr.base))
      || (addr.indx && REG_P (addr.indx) && REG_POINTER (addr.indx)))
    return TRUE;

  return FALSE;
}

/* Emit a forced load-address operation to load SRC into DST.
   This will use the LOAD ADDRESS instruction even in situations
   where legitimate_la_operand_p (SRC) returns false.  */

void
s390_load_address (rtx dst, rtx src)
{
  if (TARGET_64BIT)
    emit_move_insn (dst, src);
  else
    emit_insn (gen_force_la_31 (dst, src));
}

/* Return a legitimate reference for ORIG (an address) using the
   register REG.  If REG is 0, a new pseudo is generated.

   There are two types of references that must be handled:

   1. Global data references must load the address from the GOT, via
      the PIC reg.  An insn is emitted to do this load, and the reg is
      returned.

   2. Static data references, constant pool addresses, and code labels
      compute the address as an offset from the GOT, whose base is in
      the PIC reg.  Static data objects have SYMBOL_FLAG_LOCAL set to
      differentiate them from global data objects.  The returned
      address is the PIC reg + an unspec constant.

   GO_IF_LEGITIMATE_ADDRESS rejects symbolic references unless the PIC
   reg also appears in the address.  */

rtx
legitimize_pic_address (rtx orig, rtx reg)
{
  rtx addr = orig;
  rtx new = orig;
  rtx base;

  if (GET_CODE (addr) == LABEL_REF
      || (GET_CODE (addr) == SYMBOL_REF && SYMBOL_REF_LOCAL_P (addr)))
    {
      /* This is a local symbol.  */
      if (TARGET_CPU_ZARCH && larl_operand (addr, VOIDmode))
        {
          /* Access local symbols PC-relative via LARL.
             This is the same as in the non-PIC case, so it is
             handled automatically ...  */
        }
      else
        {
          /* Access local symbols relative to the GOT.  */

          rtx temp = reg? reg : gen_reg_rtx (Pmode);

          if (reload_in_progress || reload_completed)
            regs_ever_live[PIC_OFFSET_TABLE_REGNUM] = 1;

          addr = gen_rtx_UNSPEC (Pmode, gen_rtvec (1, addr), UNSPEC_GOTOFF);
          addr = gen_rtx_CONST (Pmode, addr);
          addr = force_const_mem (Pmode, addr);
          emit_move_insn (temp, addr);

          new = gen_rtx_PLUS (Pmode, pic_offset_table_rtx, temp);
          if (reg != 0)
            {
              emit_move_insn (reg, new);
              new = reg;
            }
        }
    }
  else if (GET_CODE (addr) == SYMBOL_REF)
    {
      if (reg == 0)
        reg = gen_reg_rtx (Pmode);

      if (flag_pic == 1)
        {
          /* Assume GOT offset < 4k.  This is handled the same way
             in both 31- and 64-bit code (@GOT).  */

          if (reload_in_progress || reload_completed)
            regs_ever_live[PIC_OFFSET_TABLE_REGNUM] = 1;

          new = gen_rtx_UNSPEC (Pmode, gen_rtvec (1, addr), UNSPEC_GOT);
          new = gen_rtx_CONST (Pmode, new);
          new = gen_rtx_PLUS (Pmode, pic_offset_table_rtx, new);
          new = gen_rtx_MEM (Pmode, new);
          RTX_UNCHANGING_P (new) = 1;
          emit_move_insn (reg, new);
          new = reg;
        }
      else if (TARGET_CPU_ZARCH)
        {
          /* If the GOT offset might be >= 4k, we determine the position
             of the GOT entry via a PC-relative LARL (@GOTENT).  */

          rtx temp = gen_reg_rtx (Pmode);

          new = gen_rtx_UNSPEC (Pmode, gen_rtvec (1, addr), UNSPEC_GOTENT);
          new = gen_rtx_CONST (Pmode, new);
          emit_move_insn (temp, new);

          new = gen_rtx_MEM (Pmode, temp);
          RTX_UNCHANGING_P (new) = 1;
          emit_move_insn (reg, new);
          new = reg;
        }
      else
        {
          /* If the GOT offset might be >= 4k, we have to load it
             from the literal pool (@GOT).  */

          rtx temp = gen_reg_rtx (Pmode);

          if (reload_in_progress || reload_completed)
            regs_ever_live[PIC_OFFSET_TABLE_REGNUM] = 1;

          addr = gen_rtx_UNSPEC (Pmode, gen_rtvec (1, addr), UNSPEC_GOT);
          addr = gen_rtx_CONST (Pmode, addr);
          addr = force_const_mem (Pmode, addr);
          emit_move_insn (temp, addr);

          new = gen_rtx_PLUS (Pmode, pic_offset_table_rtx, temp);
          new = gen_rtx_MEM (Pmode, new);
          RTX_UNCHANGING_P (new) = 1;
          emit_move_insn (reg, new);
          new = reg;
        }
    }
  else
    {
      if (GET_CODE (addr) == CONST)
        {
          addr = XEXP (addr, 0);
          if (GET_CODE (addr) == UNSPEC)
            {
              if (XVECLEN (addr, 0) != 1)
                abort ();
              switch (XINT (addr, 1))
                {
                  /* If someone moved a GOT-relative UNSPEC
                     out of the literal pool, force them back in.  */
                  case UNSPEC_GOTOFF:
                  case UNSPEC_PLTOFF:
                    new = force_const_mem (Pmode, orig);
                    break;

                  /* @GOT is OK as is if small.  */
                  case UNSPEC_GOT:
                    if (flag_pic == 2)
                      new = force_const_mem (Pmode, orig);
                    break;

                  /* @GOTENT is OK as is.  */
                  case UNSPEC_GOTENT:
                    break;

                  /* @PLT is OK as is on 64-bit, must be converted to
                     GOT-relative @PLTOFF on 31-bit.  */
                  case UNSPEC_PLT:
                    if (!TARGET_CPU_ZARCH)
                      {
                        rtx temp = reg? reg : gen_reg_rtx (Pmode);

                        if (reload_in_progress || reload_completed)
                          regs_ever_live[PIC_OFFSET_TABLE_REGNUM] = 1;

                        addr = XVECEXP (addr, 0, 0);
                        addr = gen_rtx_UNSPEC (Pmode, gen_rtvec (1, addr),
                                               UNSPEC_PLTOFF);
                        addr = gen_rtx_CONST (Pmode, addr);
                        addr = force_const_mem (Pmode, addr);
                        emit_move_insn (temp, addr);

                        new = gen_rtx_PLUS (Pmode, pic_offset_table_rtx, temp);
                        if (reg != 0)
                          {
                            emit_move_insn (reg, new);
                            new = reg;
                          }
                      }
                    break;

                  /* Everything else cannot happen.  */
                  default:
                    abort ();
                }
            }
          else if (GET_CODE (addr) != PLUS)
            abort ();
        }
      if (GET_CODE (addr) == PLUS)
        {
          rtx op0 = XEXP (addr, 0), op1 = XEXP (addr, 1);
          /* Check first to see if this is a constant offset
             from a local symbol reference.  */
          if ((GET_CODE (op0) == LABEL_REF
                || (GET_CODE (op0) == SYMBOL_REF && SYMBOL_REF_LOCAL_P (op0)))
              && GET_CODE (op1) == CONST_INT)
            {
              if (TARGET_CPU_ZARCH && larl_operand (op0, VOIDmode))
                {
                  if (INTVAL (op1) & 1)
                    {
                      /* LARL can't handle odd offsets, so emit a
                         pair of LARL and LA.  */
                      rtx temp = reg? reg : gen_reg_rtx (Pmode);

                      if (!DISP_IN_RANGE (INTVAL (op1)))
                        {
                          int even = INTVAL (op1) - 1;
                          op0 = gen_rtx_PLUS (Pmode, op0, GEN_INT (even));
                          op0 = gen_rtx_CONST (Pmode, op0);
                          op1 = const1_rtx;
                        }

                      emit_move_insn (temp, op0);
                      new = gen_rtx_PLUS (Pmode, temp, op1);

                      if (reg != 0)
                        {
                          emit_move_insn (reg, new);
                          new = reg;
                        }
                    }
                  else
                    {
                      /* If the offset is even, we can just use LARL.
                         This will happen automatically.  */
                    }
                }
              else
                {
                  /* Access local symbols relative to the GOT.  */

                  rtx temp = reg? reg : gen_reg_rtx (Pmode);

                  if (reload_in_progress || reload_completed)
                    regs_ever_live[PIC_OFFSET_TABLE_REGNUM] = 1;

                  addr = gen_rtx_UNSPEC (Pmode, gen_rtvec (1, op0),
                                         UNSPEC_GOTOFF);
                  addr = gen_rtx_PLUS (Pmode, addr, op1);
                  addr = gen_rtx_CONST (Pmode, addr);
                  addr = force_const_mem (Pmode, addr);
                  emit_move_insn (temp, addr);

                  new = gen_rtx_PLUS (Pmode, pic_offset_table_rtx, temp);
                  if (reg != 0)
                    {
                      emit_move_insn (reg, new);
                      new = reg;
                    }
                }
            }

          /* Now, check whether it is a GOT relative symbol plus offset
             that was pulled out of the literal pool.  Force it back in.  */

          else if (GET_CODE (op0) == UNSPEC
                   && GET_CODE (op1) == CONST_INT
                   && XINT (op0, 1) == UNSPEC_GOTOFF)
            {
              if (XVECLEN (op0, 0) != 1)
                abort ();

              new = force_const_mem (Pmode, orig);
            }

          /* Otherwise, compute the sum.  */
          else
            {
              base = legitimize_pic_address (XEXP (addr, 0), reg);
              new  = legitimize_pic_address (XEXP (addr, 1),
                                             base == reg ? NULL_RTX : reg);
              if (GET_CODE (new) == CONST_INT)
                new = plus_constant (base, INTVAL (new));
              else
                {
                  if (GET_CODE (new) == PLUS && CONSTANT_P (XEXP (new, 1)))
                    {
                      base = gen_rtx_PLUS (Pmode, base, XEXP (new, 0));
                      new = XEXP (new, 1);
                    }
                  new = gen_rtx_PLUS (Pmode, base, new);
                }

              if (GET_CODE (new) == CONST)
                new = XEXP (new, 0);
              new = force_operand (new, 0);
            }
        }
    }
  return new;
}

/* Load the thread pointer into a register.  */

static rtx
get_thread_pointer (void)
{
  rtx tp;

  tp = gen_rtx_UNSPEC (Pmode, gen_rtvec (1, const0_rtx), UNSPEC_TP);
  tp = force_reg (Pmode, tp);
  mark_reg_pointer (tp, BITS_PER_WORD);

  return tp;
}

/* Emit a tls call insn. The call target is the SYMBOL_REF stored
   in s390_tls_symbol which always refers to __tls_get_offset.
   The returned offset is written to RESULT_REG and an USE rtx is
   generated for TLS_CALL.  */

static GTY(()) rtx s390_tls_symbol;

static void
s390_emit_tls_call_insn (rtx result_reg, rtx tls_call)
{
  rtx insn;

  if (!flag_pic)
    abort ();

  if (!s390_tls_symbol)
    s390_tls_symbol = gen_rtx_SYMBOL_REF (Pmode, "__tls_get_offset");

  insn = s390_emit_call (s390_tls_symbol, tls_call, result_reg,
                         gen_rtx_REG (Pmode, RETURN_REGNUM));

  use_reg (&CALL_INSN_FUNCTION_USAGE (insn), result_reg);
  CONST_OR_PURE_CALL_P (insn) = 1;
}

/* ADDR contains a thread-local SYMBOL_REF.  Generate code to compute
   this (thread-local) address.  REG may be used as temporary.  */

static rtx
legitimize_tls_address (rtx addr, rtx reg)
{
  rtx new, tls_call, temp, base, r2, insn;

  if (GET_CODE (addr) == SYMBOL_REF)
    switch (tls_symbolic_operand (addr))
      {
      case TLS_MODEL_GLOBAL_DYNAMIC:
        start_sequence ();
        r2 = gen_rtx_REG (Pmode, 2);
        tls_call = gen_rtx_UNSPEC (Pmode, gen_rtvec (1, addr), UNSPEC_TLSGD);
        new = gen_rtx_CONST (Pmode, tls_call);
        new = force_const_mem (Pmode, new);
        emit_move_insn (r2, new);
        s390_emit_tls_call_insn (r2, tls_call);
        insn = get_insns ();
        end_sequence ();

        new = gen_rtx_UNSPEC (Pmode, gen_rtvec (1, addr), UNSPEC_NTPOFF);
        temp = gen_reg_rtx (Pmode);
        emit_libcall_block (insn, temp, r2, new);

        new = gen_rtx_PLUS (Pmode, get_thread_pointer (), temp);
        if (reg != 0)
          {
            s390_load_address (reg, new);
            new = reg;
          }
        break;

      case TLS_MODEL_LOCAL_DYNAMIC:
        start_sequence ();
        r2 = gen_rtx_REG (Pmode, 2);
        tls_call = gen_rtx_UNSPEC (Pmode, gen_rtvec (1, const0_rtx), UNSPEC_TLSLDM);
        new = gen_rtx_CONST (Pmode, tls_call);
        new = force_const_mem (Pmode, new);
        emit_move_insn (r2, new);
        s390_emit_tls_call_insn (r2, tls_call);
        insn = get_insns ();
        end_sequence ();

        new = gen_rtx_UNSPEC (Pmode, gen_rtvec (1, const0_rtx), UNSPEC_TLSLDM_NTPOFF);
        temp = gen_reg_rtx (Pmode);
        emit_libcall_block (insn, temp, r2, new);

        new = gen_rtx_PLUS (Pmode, get_thread_pointer (), temp);
        base = gen_reg_rtx (Pmode);
        s390_load_address (base, new);

        new = gen_rtx_UNSPEC (Pmode, gen_rtvec (1, addr), UNSPEC_DTPOFF);
        new = gen_rtx_CONST (Pmode, new);
        new = force_const_mem (Pmode, new);
        temp = gen_reg_rtx (Pmode);
        emit_move_insn (temp, new);

        new = gen_rtx_PLUS (Pmode, base, temp);
        if (reg != 0)
          {
            s390_load_address (reg, new);
            new = reg;
          }
        break;

      case TLS_MODEL_INITIAL_EXEC:
        if (flag_pic == 1)
          {
            /* Assume GOT offset < 4k.  This is handled the same way
               in both 31- and 64-bit code.  */

            if (reload_in_progress || reload_completed)
              regs_ever_live[PIC_OFFSET_TABLE_REGNUM] = 1;

            new = gen_rtx_UNSPEC (Pmode, gen_rtvec (1, addr), UNSPEC_GOTNTPOFF);
            new = gen_rtx_CONST (Pmode, new);
            new = gen_rtx_PLUS (Pmode, pic_offset_table_rtx, new);
            new = gen_rtx_MEM (Pmode, new);
            RTX_UNCHANGING_P (new) = 1;
            temp = gen_reg_rtx (Pmode);
            emit_move_insn (temp, new);
          }
        else if (TARGET_CPU_ZARCH)
          {
            /* If the GOT offset might be >= 4k, we determine the position
               of the GOT entry via a PC-relative LARL.  */

            new = gen_rtx_UNSPEC (Pmode, gen_rtvec (1, addr), UNSPEC_INDNTPOFF);
            new = gen_rtx_CONST (Pmode, new);
            temp = gen_reg_rtx (Pmode);
            emit_move_insn (temp, new);

            new = gen_rtx_MEM (Pmode, temp);
            RTX_UNCHANGING_P (new) = 1;
            temp = gen_reg_rtx (Pmode);
            emit_move_insn (temp, new);
          }
        else if (flag_pic)
          {
            /* If the GOT offset might be >= 4k, we have to load it
               from the literal pool.  */

            if (reload_in_progress || reload_completed)
              regs_ever_live[PIC_OFFSET_TABLE_REGNUM] = 1;

            new = gen_rtx_UNSPEC (Pmode, gen_rtvec (1, addr), UNSPEC_GOTNTPOFF);
            new = gen_rtx_CONST (Pmode, new);
            new = force_const_mem (Pmode, new);
            temp = gen_reg_rtx (Pmode);
            emit_move_insn (temp, new);

            new = gen_rtx_PLUS (Pmode, pic_offset_table_rtx, temp);
            new = gen_rtx_MEM (Pmode, new);
            RTX_UNCHANGING_P (new) = 1;

            new = gen_rtx_UNSPEC (Pmode, gen_rtvec (2, new, addr), UNSPEC_TLS_LOAD);
            temp = gen_reg_rtx (Pmode);
            emit_insn (gen_rtx_SET (Pmode, temp, new));
          }
        else
          {
            /* In position-dependent code, load the absolute address of
               the GOT entry from the literal pool.  */

            new = gen_rtx_UNSPEC (Pmode, gen_rtvec (1, addr), UNSPEC_INDNTPOFF);
            new = gen_rtx_CONST (Pmode, new);
            new = force_const_mem (Pmode, new);
            temp = gen_reg_rtx (Pmode);
            emit_move_insn (temp, new);

            new = temp;
            new = gen_rtx_MEM (Pmode, new);
            RTX_UNCHANGING_P (new) = 1;

            new = gen_rtx_UNSPEC (Pmode, gen_rtvec (2, new, addr), UNSPEC_TLS_LOAD);
            temp = gen_reg_rtx (Pmode);
            emit_insn (gen_rtx_SET (Pmode, temp, new));
          }

        new = gen_rtx_PLUS (Pmode, get_thread_pointer (), temp);
        if (reg != 0)
          {
            s390_load_address (reg, new);
            new = reg;
          }
        break;

      case TLS_MODEL_LOCAL_EXEC:
        new = gen_rtx_UNSPEC (Pmode, gen_rtvec (1, addr), UNSPEC_NTPOFF);
        new = gen_rtx_CONST (Pmode, new);
        new = force_const_mem (Pmode, new);
        temp = gen_reg_rtx (Pmode);
        emit_move_insn (temp, new);

        new = gen_rtx_PLUS (Pmode, get_thread_pointer (), temp);
        if (reg != 0)
          {
            s390_load_address (reg, new);
            new = reg;
          }
        break;

      default:
        abort ();
      }

  else if (GET_CODE (addr) == CONST && GET_CODE (XEXP (addr, 0)) == UNSPEC)
    {
      switch (XINT (XEXP (addr, 0), 1))
        {
        case UNSPEC_INDNTPOFF:
          if (TARGET_CPU_ZARCH)
            new = addr;
          else
            abort ();
          break;

        default:
          abort ();
        }
    }

  else
    abort ();  /* for now ... */

  return new;
}

/* Emit insns to move operands[1] into operands[0].  */

void
emit_symbolic_move (rtx *operands)
{
  rtx temp = no_new_pseudos ? operands[0] : gen_reg_rtx (Pmode);

  if (GET_CODE (operands[0]) == MEM)
    operands[1] = force_reg (Pmode, operands[1]);
  else if (TLS_SYMBOLIC_CONST (operands[1]))
    operands[1] = legitimize_tls_address (operands[1], temp);
  else if (flag_pic)
    operands[1] = legitimize_pic_address (operands[1], temp);
}

/* Try machine-dependent ways of modifying an illegitimate address X
   to be legitimate.  If we find one, return the new, valid address.

   OLDX is the address as it was before break_out_memory_refs was called.
   In some cases it is useful to look at this to decide what needs to be done.

   MODE is the mode of the operand pointed to by X.

   When -fpic is used, special handling is needed for symbolic references.
   See comments by legitimize_pic_address for details.  */

rtx
legitimize_address (register rtx x, register rtx oldx ATTRIBUTE_UNUSED,
                    enum machine_mode mode ATTRIBUTE_UNUSED)
{
  rtx constant_term = const0_rtx;

  if (TLS_SYMBOLIC_CONST (x))
    {
      x = legitimize_tls_address (x, 0);

      if (legitimate_address_p (mode, x, FALSE))
        return x;
    }
  else if (flag_pic)
    {
      if (SYMBOLIC_CONST (x)
          || (GET_CODE (x) == PLUS
              && (SYMBOLIC_CONST (XEXP (x, 0))
                  || SYMBOLIC_CONST (XEXP (x, 1)))))
          x = legitimize_pic_address (x, 0);

      if (legitimate_address_p (mode, x, FALSE))
        return x;
    }

  x = eliminate_constant_term (x, &constant_term);

  /* Optimize loading of large displacements by splitting them
     into the multiple of 4K and the rest; this allows the
     former to be CSE'd if possible.

     Don't do this if the displacement is added to a register
     pointing into the stack frame, as the offsets will
     change later anyway.  */

  if (GET_CODE (constant_term) == CONST_INT
      && !TARGET_LONG_DISPLACEMENT
      && !DISP_IN_RANGE (INTVAL (constant_term))
      && !(REG_P (x) && REGNO_PTR_FRAME_P (REGNO (x))))
    {
      HOST_WIDE_INT lower = INTVAL (constant_term) & 0xfff;
      HOST_WIDE_INT upper = INTVAL (constant_term) ^ lower;

      rtx temp = gen_reg_rtx (Pmode);
      rtx val  = force_operand (GEN_INT (upper), temp);
      if (val != temp)
        emit_move_insn (temp, val);

      x = gen_rtx_PLUS (Pmode, x, temp);
      constant_term = GEN_INT (lower);
    }

  if (GET_CODE (x) == PLUS)
    {
      if (GET_CODE (XEXP (x, 0)) == REG)
        {
          register rtx temp = gen_reg_rtx (Pmode);
          register rtx val  = force_operand (XEXP (x, 1), temp);
          if (val != temp)
            emit_move_insn (temp, val);

          x = gen_rtx_PLUS (Pmode, XEXP (x, 0), temp);
        }

      else if (GET_CODE (XEXP (x, 1)) == REG)
        {
          register rtx temp = gen_reg_rtx (Pmode);
          register rtx val  = force_operand (XEXP (x, 0), temp);
          if (val != temp)
            emit_move_insn (temp, val);

          x = gen_rtx_PLUS (Pmode, temp, XEXP (x, 1));
        }
    }

  if (constant_term != const0_rtx)
    x = gen_rtx_PLUS (Pmode, x, constant_term);

  return x;
}

/* Emit code to move LEN bytes from DST to SRC.  */

void
s390_expand_movmem (rtx dst, rtx src, rtx len)
{
  if (GET_CODE (len) == CONST_INT && INTVAL (len) >= 0 && INTVAL (len) <= 256)
    {
      if (INTVAL (len) > 0)
        emit_insn (gen_movmem_short (dst, src, GEN_INT (INTVAL (len) - 1)));
    }

  else if (TARGET_MVCLE)
    {
      emit_insn (gen_movmem_long (dst, src, convert_to_mode (Pmode, len, 1)));
    }

  else
    {
      rtx dst_addr, src_addr, count, blocks, temp;
      rtx loop_start_label = gen_label_rtx ();
      rtx loop_end_label = gen_label_rtx ();
      rtx end_label = gen_label_rtx ();
      enum machine_mode mode;

      mode = GET_MODE (len);
      if (mode == VOIDmode)
        mode = Pmode;

      dst_addr = gen_reg_rtx (Pmode);
      src_addr = gen_reg_rtx (Pmode);
      count = gen_reg_rtx (mode);
      blocks = gen_reg_rtx (mode);

      convert_move (count, len, 1);
      emit_cmp_and_jump_insns (count, const0_rtx,
                               EQ, NULL_RTX, mode, 1, end_label);

      emit_move_insn (dst_addr, force_operand (XEXP (dst, 0), NULL_RTX));
      emit_move_insn (src_addr, force_operand (XEXP (src, 0), NULL_RTX));
      dst = change_address (dst, VOIDmode, dst_addr);
      src = change_address (src, VOIDmode, src_addr);

      temp = expand_binop (mode, add_optab, count, constm1_rtx, count, 1, 0);
      if (temp != count)
        emit_move_insn (count, temp);

      temp = expand_binop (mode, ashr_optab, count, GEN_INT (8), blocks, 1, 0);
      if (temp != blocks)
        emit_move_insn (blocks, temp);

      emit_cmp_and_jump_insns (blocks, const0_rtx,
                               EQ, NULL_RTX, mode, 1, loop_end_label);

      emit_label (loop_start_label);

      emit_insn (gen_movmem_short (dst, src, GEN_INT (255)));
      s390_load_address (dst_addr,
                         gen_rtx_PLUS (Pmode, dst_addr, GEN_INT (256)));
      s390_load_address (src_addr,
                         gen_rtx_PLUS (Pmode, src_addr, GEN_INT (256)));

      temp = expand_binop (mode, add_optab, blocks, constm1_rtx, blocks, 1, 0);
      if (temp != blocks)
        emit_move_insn (blocks, temp);

      emit_cmp_and_jump_insns (blocks, const0_rtx,
                               EQ, NULL_RTX, mode, 1, loop_end_label);

      emit_jump (loop_start_label);
      emit_label (loop_end_label);

      emit_insn (gen_movmem_short (dst, src,
                                   convert_to_mode (Pmode, count, 1)));
      emit_label (end_label);
    }
}

/* Emit code to clear LEN bytes at DST.  */

void
s390_expand_clrmem (rtx dst, rtx len)
{
  if (GET_CODE (len) == CONST_INT && INTVAL (len) >= 0 && INTVAL (len) <= 256)
    {
      if (INTVAL (len) > 0)
        emit_insn (gen_clrmem_short (dst, GEN_INT (INTVAL (len) - 1)));
    }

  else if (TARGET_MVCLE)
    {
      emit_insn (gen_clrmem_long (dst, convert_to_mode (Pmode, len, 1)));
    }

  else
    {
      rtx dst_addr, src_addr, count, blocks, temp;
      rtx loop_start_label = gen_label_rtx ();
      rtx loop_end_label = gen_label_rtx ();
      rtx end_label = gen_label_rtx ();
      enum machine_mode mode;

      mode = GET_MODE (len);
      if (mode == VOIDmode)
        mode = Pmode;

      dst_addr = gen_reg_rtx (Pmode);
      src_addr = gen_reg_rtx (Pmode);
      count = gen_reg_rtx (mode);
      blocks = gen_reg_rtx (mode);

      convert_move (count, len, 1);
      emit_cmp_and_jump_insns (count, const0_rtx,
                               EQ, NULL_RTX, mode, 1, end_label);

      emit_move_insn (dst_addr, force_operand (XEXP (dst, 0), NULL_RTX));
      dst = change_address (dst, VOIDmode, dst_addr);

      temp = expand_binop (mode, add_optab, count, constm1_rtx, count, 1, 0);
      if (temp != count)
        emit_move_insn (count, temp);

      temp = expand_binop (mode, ashr_optab, count, GEN_INT (8), blocks, 1, 0);
      if (temp != blocks)
        emit_move_insn (blocks, temp);

      emit_cmp_and_jump_insns (blocks, const0_rtx,
                               EQ, NULL_RTX, mode, 1, loop_end_label);

      emit_label (loop_start_label);

      emit_insn (gen_clrmem_short (dst, GEN_INT (255)));
      s390_load_address (dst_addr,
                         gen_rtx_PLUS (Pmode, dst_addr, GEN_INT (256)));

      temp = expand_binop (mode, add_optab, blocks, constm1_rtx, blocks, 1, 0);
      if (temp != blocks)
        emit_move_insn (blocks, temp);

      emit_cmp_and_jump_insns (blocks, const0_rtx,
                               EQ, NULL_RTX, mode, 1, loop_end_label);

      emit_jump (loop_start_label);
      emit_label (loop_end_label);

      emit_insn (gen_clrmem_short (dst, convert_to_mode (Pmode, count, 1)));
      emit_label (end_label);
    }
}

/* Emit code to compare LEN bytes at OP0 with those at OP1,
   and return the result in TARGET.  */

void
s390_expand_cmpmem (rtx target, rtx op0, rtx op1, rtx len)
{
  rtx (*gen_result) (rtx) =
    GET_MODE (target) == DImode ? gen_cmpint_di : gen_cmpint_si;

  op0 = protect_from_queue (op0, 0);
  op1 = protect_from_queue (op1, 0);
  len = protect_from_queue (len, 0);

  if (GET_CODE (len) == CONST_INT && INTVAL (len) >= 0 && INTVAL (len) <= 256)
    {
      if (INTVAL (len) > 0)
        {
          emit_insn (gen_cmpmem_short (op0, op1, GEN_INT (INTVAL (len) - 1)));
          emit_insn (gen_result (target));
        }
      else
        emit_move_insn (target, const0_rtx);
    }

  else /* if (TARGET_MVCLE) */
    {
      emit_insn (gen_cmpmem_long (op0, op1, convert_to_mode (Pmode, len, 1)));
      emit_insn (gen_result (target));
    }

#if 0
  /* Deactivate for now as profile code cannot cope with
     CC being live across basic block boundaries.  */
  else
    {
      rtx addr0, addr1, count, blocks, temp;
      rtx loop_start_label = gen_label_rtx ();
      rtx loop_end_label = gen_label_rtx ();
      rtx end_label = gen_label_rtx ();
      enum machine_mode mode;

      mode = GET_MODE (len);
      if (mode == VOIDmode)
        mode = Pmode;

      addr0 = gen_reg_rtx (Pmode);
      addr1 = gen_reg_rtx (Pmode);
      count = gen_reg_rtx (mode);
      blocks = gen_reg_rtx (mode);

      convert_move (count, len, 1);
      emit_cmp_and_jump_insns (count, const0_rtx,
                               EQ, NULL_RTX, mode, 1, end_label);

      emit_move_insn (addr0, force_operand (XEXP (op0, 0), NULL_RTX));
      emit_move_insn (addr1, force_operand (XEXP (op1, 0), NULL_RTX));
      op0 = change_address (op0, VOIDmode, addr0);
      op1 = change_address (op1, VOIDmode, addr1);

      temp = expand_binop (mode, add_optab, count, constm1_rtx, count, 1, 0);
      if (temp != count)
        emit_move_insn (count, temp);

      temp = expand_binop (mode, ashr_optab, count, GEN_INT (8), blocks, 1, 0);
      if (temp != blocks)
        emit_move_insn (blocks, temp);

      emit_cmp_and_jump_insns (blocks, const0_rtx,
                               EQ, NULL_RTX, mode, 1, loop_end_label);

      emit_label (loop_start_label);

      emit_insn (gen_cmpmem_short (op0, op1, GEN_INT (255)));
      temp = gen_rtx_NE (VOIDmode, gen_rtx_REG (CCSmode, 33), const0_rtx);
      temp = gen_rtx_IF_THEN_ELSE (VOIDmode, temp,
                        gen_rtx_LABEL_REF (VOIDmode, end_label), pc_rtx);
      temp = gen_rtx_SET (VOIDmode, pc_rtx, temp);
      emit_jump_insn (temp);

      s390_load_address (addr0,
                         gen_rtx_PLUS (Pmode, addr0, GEN_INT (256)));
      s390_load_address (addr1,
                         gen_rtx_PLUS (Pmode, addr1, GEN_INT (256)));

      temp = expand_binop (mode, add_optab, blocks, constm1_rtx, blocks, 1, 0);
      if (temp != blocks)
        emit_move_insn (blocks, temp);

      emit_cmp_and_jump_insns (blocks, const0_rtx,
                               EQ, NULL_RTX, mode, 1, loop_end_label);

      emit_jump (loop_start_label);
      emit_label (loop_end_label);

      emit_insn (gen_cmpmem_short (op0, op1,
                                   convert_to_mode (Pmode, count, 1)));
      emit_label (end_label);

      emit_insn (gen_result (target));
    }
#endif
}


/* Expand conditional increment or decrement using alc/slb instructions.
   Should generate code setting DST to either SRC or SRC + INCREMENT,
   depending on the result of the comparison CMP_OP0 CMP_CODE CMP_OP1.
   Returns true if successful, false otherwise.  */

bool
s390_expand_addcc (enum rtx_code cmp_code, rtx cmp_op0, rtx cmp_op1,
                   rtx dst, rtx src, rtx increment)
{
  enum machine_mode cmp_mode;
  enum machine_mode cc_mode;
  rtx op_res;
  rtx insn;
  rtvec p;

  if ((GET_MODE (cmp_op0) == SImode || GET_MODE (cmp_op0) == VOIDmode)
      && (GET_MODE (cmp_op1) == SImode || GET_MODE (cmp_op1) == VOIDmode))
    cmp_mode = SImode;
  else if ((GET_MODE (cmp_op0) == DImode || GET_MODE (cmp_op0) == VOIDmode)
           && (GET_MODE (cmp_op1) == DImode || GET_MODE (cmp_op1) == VOIDmode))
    cmp_mode = DImode;
  else
    return false;

  /* Try ADD LOGICAL WITH CARRY.  */
  if (increment == const1_rtx)
    {
      /* Determine CC mode to use.  */
      if (cmp_code == EQ || cmp_code == NE)
        {
          if (cmp_op1 != const0_rtx)
            {
              cmp_op0 = expand_simple_binop (cmp_mode, XOR, cmp_op0, cmp_op1,
                                             NULL_RTX, 0, OPTAB_WIDEN);
              cmp_op1 = const0_rtx;
            }

          cmp_code = cmp_code == EQ ? LEU : GTU;
        }

      if (cmp_code == LTU || cmp_code == LEU)
        {
          rtx tem = cmp_op0;
          cmp_op0 = cmp_op1;
          cmp_op1 = tem;
          cmp_code = swap_condition (cmp_code);
        }

      switch (cmp_code)
        {
          case GTU:
            cc_mode = CCUmode;
            break;

          case GEU:
            cc_mode = CCL3mode;
            break;

          default:
            return false;
        }

      /* Emit comparison instruction pattern. */
      if (!register_operand (cmp_op0, cmp_mode))
        cmp_op0 = force_reg (cmp_mode, cmp_op0);

      insn = gen_rtx_SET (VOIDmode, gen_rtx_REG (cc_mode, CC_REGNUM),
                          gen_rtx_COMPARE (cc_mode, cmp_op0, cmp_op1));
      /* We use insn_invalid_p here to add clobbers if required.  */
      if (insn_invalid_p (emit_insn (insn)))
        abort ();

      /* Emit ALC instruction pattern.  */
      op_res = gen_rtx_fmt_ee (cmp_code, GET_MODE (dst),
                               gen_rtx_REG (cc_mode, CC_REGNUM),
                               const0_rtx);

      if (src != const0_rtx)
        {
          if (!register_operand (src, GET_MODE (dst)))
            src = force_reg (GET_MODE (dst), src);

          src = gen_rtx_PLUS (GET_MODE (dst), src, const0_rtx);
          op_res = gen_rtx_PLUS (GET_MODE (dst), src, op_res);
        }

      p = rtvec_alloc (2);
      RTVEC_ELT (p, 0) = 
        gen_rtx_SET (VOIDmode, dst, op_res);
      RTVEC_ELT (p, 1) = 
        gen_rtx_CLOBBER (VOIDmode, gen_rtx_REG (CCmode, CC_REGNUM));
      emit_insn (gen_rtx_PARALLEL (VOIDmode, p));

      return true;
    }

  /* Try SUBTRACT LOGICAL WITH BORROW.  */
  if (increment == constm1_rtx)
    {
      /* Determine CC mode to use.  */
      if (cmp_code == EQ || cmp_code == NE)
        {
          if (cmp_op1 != const0_rtx)
            {
              cmp_op0 = expand_simple_binop (cmp_mode, XOR, cmp_op0, cmp_op1,
                                             NULL_RTX, 0, OPTAB_WIDEN);
              cmp_op1 = const0_rtx;
            }

          cmp_code = cmp_code == EQ ? LEU : GTU;
        }

      if (cmp_code == GTU || cmp_code == GEU)
        {
          rtx tem = cmp_op0;
          cmp_op0 = cmp_op1;
          cmp_op1 = tem;
          cmp_code = swap_condition (cmp_code);
        }

      switch (cmp_code)
        {
          case LEU:
            cc_mode = CCUmode;
            break;

          case LTU:
            cc_mode = CCL3mode;
            break;

          default:
            return false;
        }

      /* Emit comparison instruction pattern. */
      if (!register_operand (cmp_op0, cmp_mode))
        cmp_op0 = force_reg (cmp_mode, cmp_op0);

      insn = gen_rtx_SET (VOIDmode, gen_rtx_REG (cc_mode, CC_REGNUM),
                          gen_rtx_COMPARE (cc_mode, cmp_op0, cmp_op1));
      /* We use insn_invalid_p here to add clobbers if required.  */
      if (insn_invalid_p (emit_insn (insn)))
        abort ();

      /* Emit SLB instruction pattern.  */
      if (!register_operand (src, GET_MODE (dst)))
        src = force_reg (GET_MODE (dst), src);

      op_res = gen_rtx_MINUS (GET_MODE (dst), 
                              gen_rtx_MINUS (GET_MODE (dst), src, const0_rtx), 
                              gen_rtx_fmt_ee (cmp_code, GET_MODE (dst), 
                                              gen_rtx_REG (cc_mode, CC_REGNUM), 
                                              const0_rtx));
      p = rtvec_alloc (2);
      RTVEC_ELT (p, 0) = 
        gen_rtx_SET (VOIDmode, dst, op_res);
      RTVEC_ELT (p, 1) = 
        gen_rtx_CLOBBER (VOIDmode, gen_rtx_REG (CCmode, CC_REGNUM));
      emit_insn (gen_rtx_PARALLEL (VOIDmode, p));

      return true;
    }

  return false;
}


/* This is called from dwarf2out.c via ASM_OUTPUT_DWARF_DTPREL.
   We need to emit DTP-relative relocations.  */

void
s390_output_dwarf_dtprel (FILE *file, int size, rtx x)
{
  switch (size)
    {
    case 4:
      fputs ("\t.long\t", file);
      break;
    case 8:
      fputs ("\t.quad\t", file);
      break;
    default:
      abort ();
    }
  output_addr_const (file, x);
  fputs ("@DTPOFF", file);
}

/* In the name of slightly smaller debug output, and to cater to
   general assembler losage, recognize various UNSPEC sequences
   and turn them back into a direct symbol reference.  */

static rtx
s390_delegitimize_address (rtx orig_x)
{
  rtx x = orig_x, y;

  if (GET_CODE (x) != MEM)
    return orig_x;

  x = XEXP (x, 0);
  if (GET_CODE (x) == PLUS
      && GET_CODE (XEXP (x, 1)) == CONST
      && GET_CODE (XEXP (x, 0)) == REG
      && REGNO (XEXP (x, 0)) == PIC_OFFSET_TABLE_REGNUM)
    {
      y = XEXP (XEXP (x, 1), 0);
      if (GET_CODE (y) == UNSPEC
          && XINT (y, 1) == UNSPEC_GOT)
        return XVECEXP (y, 0, 0);
      return orig_x;
    }

  if (GET_CODE (x) == CONST)
    {
      y = XEXP (x, 0);
      if (GET_CODE (y) == UNSPEC
          && XINT (y, 1) == UNSPEC_GOTENT)
        return XVECEXP (y, 0, 0);
      return orig_x;
    }

  return orig_x;
}

/* Output shift count operand OP to stdio stream FILE.  */

static void
print_shift_count_operand (FILE *file, rtx op)
{
  HOST_WIDE_INT offset = 0;

  /* We can have an integer constant, an address register,
     or a sum of the two.  */
  if (GET_CODE (op) == CONST_INT)
    {
      offset = INTVAL (op);
      op = NULL_RTX;
    }
  if (op && GET_CODE (op) == PLUS && GET_CODE (XEXP (op, 1)) == CONST_INT)
    {
      offset = INTVAL (XEXP (op, 1));
      op = XEXP (op, 0);
    }
  while (op && GET_CODE (op) == SUBREG)
    op = SUBREG_REG (op);

  /* Sanity check.  */
  if (op && (GET_CODE (op) != REG
             || REGNO (op) >= FIRST_PSEUDO_REGISTER
             || REGNO_REG_CLASS (REGNO (op)) != ADDR_REGS))
    abort ();

  /* Shift counts are truncated to the low six bits anyway.  */
  fprintf (file, HOST_WIDE_INT_PRINT_DEC, offset & 63);
  if (op)
    fprintf (file, "(%s)", reg_names[REGNO (op)]);
}

/* Locate some local-dynamic symbol still in use by this function
   so that we can print its name in local-dynamic base patterns.  */

static const char *
get_some_local_dynamic_name (void)
{
  rtx insn;

  if (cfun->machine->some_ld_name)
    return cfun->machine->some_ld_name;

  for (insn = get_insns (); insn ; insn = NEXT_INSN (insn))
    if (INSN_P (insn)
        && for_each_rtx (&PATTERN (insn), get_some_local_dynamic_name_1, 0))
      return cfun->machine->some_ld_name;

  abort ();
}

static int
get_some_local_dynamic_name_1 (rtx *px, void *data ATTRIBUTE_UNUSED)
{
  rtx x = *px;

  if (GET_CODE (x) == SYMBOL_REF && CONSTANT_POOL_ADDRESS_P (x))
    {
      x = get_pool_constant (x);
      return for_each_rtx (&x, get_some_local_dynamic_name_1, 0);
    }

  if (GET_CODE (x) == SYMBOL_REF
      && tls_symbolic_operand (x) == TLS_MODEL_LOCAL_DYNAMIC)
    {
      cfun->machine->some_ld_name = XSTR (x, 0);
      return 1;
    }

  return 0;
}

/* Output machine-dependent UNSPECs occurring in address constant X
   in assembler syntax to stdio stream FILE.  Returns true if the
   constant X could be recognized, false otherwise.  */

bool
s390_output_addr_const_extra (FILE *file, rtx x)
{
  if (GET_CODE (x) == UNSPEC && XVECLEN (x, 0) == 1)
    switch (XINT (x, 1))
      {
      case UNSPEC_GOTENT:
        output_addr_const (file, XVECEXP (x, 0, 0));
        fprintf (file, "@GOTENT");
        return true;
      case UNSPEC_GOT:
        output_addr_const (file, XVECEXP (x, 0, 0));
        fprintf (file, "@GOT");
        return true;
      case UNSPEC_GOTOFF:
        output_addr_const (file, XVECEXP (x, 0, 0));
        fprintf (file, "@GOTOFF");
        return true;
      case UNSPEC_PLT:
        output_addr_const (file, XVECEXP (x, 0, 0));
        fprintf (file, "@PLT");
        return true;
      case UNSPEC_PLTOFF:
        output_addr_const (file, XVECEXP (x, 0, 0));
        fprintf (file, "@PLTOFF");
        return true;
      case UNSPEC_TLSGD:
        output_addr_const (file, XVECEXP (x, 0, 0));
        fprintf (file, "@TLSGD");
        return true;
      case UNSPEC_TLSLDM:
        assemble_name (file, get_some_local_dynamic_name ());
        fprintf (file, "@TLSLDM");
        return true;
      case UNSPEC_DTPOFF:
        output_addr_const (file, XVECEXP (x, 0, 0));
        fprintf (file, "@DTPOFF");
        return true;
      case UNSPEC_NTPOFF:
        output_addr_const (file, XVECEXP (x, 0, 0));
        fprintf (file, "@NTPOFF");
        return true;
      case UNSPEC_GOTNTPOFF:
        output_addr_const (file, XVECEXP (x, 0, 0));
        fprintf (file, "@GOTNTPOFF");
        return true;
      case UNSPEC_INDNTPOFF:
        output_addr_const (file, XVECEXP (x, 0, 0));
        fprintf (file, "@INDNTPOFF");
        return true;
      }

  return false;
}

/* Output address operand ADDR in assembler syntax to
   stdio stream FILE.  */

void
print_operand_address (FILE *file, rtx addr)
{
  struct s390_address ad;

  if (!s390_decompose_address (addr, &ad)
      || (ad.base && !REG_OK_FOR_BASE_STRICT_P (ad.base))
      || (ad.indx && !REG_OK_FOR_INDEX_STRICT_P (ad.indx)))
    output_operand_lossage ("Cannot decompose address.");

  if (ad.disp)
    output_addr_const (file, ad.disp);
  else
    fprintf (file, "0");

  if (ad.base && ad.indx)
    fprintf (file, "(%s,%s)", reg_names[REGNO (ad.indx)],
                              reg_names[REGNO (ad.base)]);
  else if (ad.base)
    fprintf (file, "(%s)", reg_names[REGNO (ad.base)]);
}

/* Output operand X in assembler syntax to stdio stream FILE.
   CODE specified the format flag.  The following format flags
   are recognized:

    'C': print opcode suffix for branch condition.
    'D': print opcode suffix for inverse branch condition.
    'J': print tls_load/tls_gdcall/tls_ldcall suffix
    'O': print only the displacement of a memory reference.
    'R': print only the base register of a memory reference.
    'N': print the second word of a DImode operand.
    'M': print the second word of a TImode operand.
    'Y': print shift count operand.

    'b': print integer X as if it's an unsigned byte.
    'x': print integer X as if it's an unsigned word.
    'h': print integer X as if it's a signed word.
    'i': print the first nonzero HImode part of X.
    'j': print the first HImode part unequal to 0xffff of X.  */

void
print_operand (FILE *file, rtx x, int code)
{
  switch (code)
    {
    case 'C':
      fprintf (file, s390_branch_condition_mnemonic (x, FALSE));
      return;

    case 'D':
      fprintf (file, s390_branch_condition_mnemonic (x, TRUE));
      return;

    case 'J':
      if (GET_CODE (x) == SYMBOL_REF)
        {
          fprintf (file, "%s", ":tls_load:");
          output_addr_const (file, x);
        }
      else if (GET_CODE (x) == UNSPEC && XINT (x, 1) == UNSPEC_TLSGD)
        {
          fprintf (file, "%s", ":tls_gdcall:");
          output_addr_const (file, XVECEXP (x, 0, 0));
        }
      else if (GET_CODE (x) == UNSPEC && XINT (x, 1) == UNSPEC_TLSLDM)
        {
          fprintf (file, "%s", ":tls_ldcall:");
          assemble_name (file, get_some_local_dynamic_name ());
        }
      else
        abort ();
      return;

    case 'O':
      {
        struct s390_address ad;

        if (GET_CODE (x) != MEM
            || !s390_decompose_address (XEXP (x, 0), &ad)
            || (ad.base && !REG_OK_FOR_BASE_STRICT_P (ad.base))
            || ad.indx)
          abort ();

        if (ad.disp)
          output_addr_const (file, ad.disp);
        else
          fprintf (file, "0");
      }
      return;

    case 'R':
      {
        struct s390_address ad;

        if (GET_CODE (x) != MEM
            || !s390_decompose_address (XEXP (x, 0), &ad)
            || (ad.base && !REG_OK_FOR_BASE_STRICT_P (ad.base))
            || ad.indx)
          abort ();

        if (ad.base)
          fprintf (file, "%s", reg_names[REGNO (ad.base)]);
        else
          fprintf (file, "0");
      }
      return;

    case 'N':
      if (GET_CODE (x) == REG)
        x = gen_rtx_REG (GET_MODE (x), REGNO (x) + 1);
      else if (GET_CODE (x) == MEM)
        x = change_address (x, VOIDmode, plus_constant (XEXP (x, 0), 4));
      else
        abort ();
      break;

    case 'M':
      if (GET_CODE (x) == REG)
        x = gen_rtx_REG (GET_MODE (x), REGNO (x) + 1);
      else if (GET_CODE (x) == MEM)
        x = change_address (x, VOIDmode, plus_constant (XEXP (x, 0), 8));
      else
        abort ();
      break;

    case 'Y':
      print_shift_count_operand (file, x);
      return;
    }

  switch (GET_CODE (x))
    {
    case REG:
      fprintf (file, "%s", reg_names[REGNO (x)]);
      break;

    case MEM:
      output_address (XEXP (x, 0));
      break;

    case CONST:
    case CODE_LABEL:
    case LABEL_REF:
    case SYMBOL_REF:
      output_addr_const (file, x);
      break;

    case CONST_INT:
      if (code == 'b')
        fprintf (file, HOST_WIDE_INT_PRINT_DEC, INTVAL (x) & 0xff);
      else if (code == 'x')
        fprintf (file, HOST_WIDE_INT_PRINT_DEC, INTVAL (x) & 0xffff);
      else if (code == 'h')
        fprintf (file, HOST_WIDE_INT_PRINT_DEC, ((INTVAL (x) & 0xffff) ^ 0x8000) - 0x8000);
      else if (code == 'i')
        fprintf (file, HOST_WIDE_INT_PRINT_DEC,
                 s390_extract_part (x, HImode, 0));
      else if (code == 'j')
        fprintf (file, HOST_WIDE_INT_PRINT_DEC,
                 s390_extract_part (x, HImode, -1));
      else
        fprintf (file, HOST_WIDE_INT_PRINT_DEC, INTVAL (x));
      break;

    case CONST_DOUBLE:
      if (GET_MODE (x) != VOIDmode)
        abort ();
      if (code == 'b')
        fprintf (file, HOST_WIDE_INT_PRINT_DEC, CONST_DOUBLE_LOW (x) & 0xff);
      else if (code == 'x')
        fprintf (file, HOST_WIDE_INT_PRINT_DEC, CONST_DOUBLE_LOW (x) & 0xffff);
      else if (code == 'h')
        fprintf (file, HOST_WIDE_INT_PRINT_DEC, ((CONST_DOUBLE_LOW (x) & 0xffff) ^ 0x8000) - 0x8000);
      else
        abort ();
      break;

    default:
      fatal_insn ("UNKNOWN in print_operand !?", x);
      break;
    }
}

/* Target hook for assembling integer objects.  We need to define it
   here to work a round a bug in some versions of GAS, which couldn't
   handle values smaller than INT_MIN when printed in decimal.  */

static bool
s390_assemble_integer (rtx x, unsigned int size, int aligned_p)
{
  if (size == 8 && aligned_p
      && GET_CODE (x) == CONST_INT && INTVAL (x) < INT_MIN)
    {
      fprintf (asm_out_file, "\t.quad\t" HOST_WIDE_INT_PRINT_HEX "\n",
               INTVAL (x));
      return true;
    }
  return default_assemble_integer (x, size, aligned_p);
}

/* Returns true if register REGNO is used  for forming
   a memory address in expression X.  */

static int
reg_used_in_mem_p (int regno, rtx x)
{
  enum rtx_code code = GET_CODE (x);
  int i, j;
  const char *fmt;

  if (code == MEM)
    {
      if (refers_to_regno_p (regno, regno+1,
                             XEXP (x, 0), 0))
        return 1;
    }
  else if (code == SET
           && GET_CODE (SET_DEST (x)) == PC)
    {
      if (refers_to_regno_p (regno, regno+1,
                             SET_SRC (x), 0))
        return 1;
    }

  fmt = GET_RTX_FORMAT (code);
  for (i = GET_RTX_LENGTH (code) - 1; i >= 0; i--)
    {
      if (fmt[i] == 'e'
          && reg_used_in_mem_p (regno, XEXP (x, i)))
        return 1;

      else if (fmt[i] == 'E')
        for (j = 0; j < XVECLEN (x, i); j++)
          if (reg_used_in_mem_p (regno, XVECEXP (x, i, j)))
            return 1;
    }
  return 0;
}

/* Returns true if expression DEP_RTX sets an address register
   used by instruction INSN to address memory.  */

static int
addr_generation_dependency_p (rtx dep_rtx, rtx insn)
{
  rtx target, pat;

  if (GET_CODE (dep_rtx) == INSN)
      dep_rtx = PATTERN (dep_rtx);

  if (GET_CODE (dep_rtx) == SET)
    {
      target = SET_DEST (dep_rtx);
      if (GET_CODE (target) == STRICT_LOW_PART)
        target = XEXP (target, 0);
      while (GET_CODE (target) == SUBREG)
        target = SUBREG_REG (target);

      if (GET_CODE (target) == REG)
        {
          int regno = REGNO (target);

          if (s390_safe_attr_type (insn) == TYPE_LA)
            {
              pat = PATTERN (insn);
              if (GET_CODE (pat) == PARALLEL)
                {
                  if (XVECLEN (pat, 0) != 2)
                    abort();
                  pat = XVECEXP (pat, 0, 0);
                }
              if (GET_CODE (pat) == SET)
                return refers_to_regno_p (regno, regno+1, SET_SRC (pat), 0);
              else
                abort();
            }
          else if (get_attr_atype (insn) == ATYPE_AGEN)
            return reg_used_in_mem_p (regno, PATTERN (insn));
        }
    }
  return 0;
}

/* Return 1, if dep_insn sets register used in insn in the agen unit.  */

int
s390_agen_dep_p (rtx dep_insn, rtx insn)
{
  rtx dep_rtx = PATTERN (dep_insn);
  int i;

  if (GET_CODE (dep_rtx) == SET
      && addr_generation_dependency_p (dep_rtx, insn))
    return 1;
  else if (GET_CODE (dep_rtx) == PARALLEL)
    {
      for (i = 0; i < XVECLEN (dep_rtx, 0); i++)
        {
          if (addr_generation_dependency_p (XVECEXP (dep_rtx, 0, i), insn))
            return 1;
        }
    }
  return 0;
}

/* Return the modified cost of the dependency of instruction INSN
   on instruction DEP_INSN through the link LINK.  COST is the
   default cost of that dependency.

   Data dependencies are all handled without delay.  However, if a
   register is modified and subsequently used as base or index
   register of a memory reference, at least 4 cycles need to pass
   between setting and using the register to avoid pipeline stalls.
   An exception is the LA instruction. An address generated by LA can
   be used by introducing only a one cycle stall on the pipeline.  */

static int
s390_adjust_cost (rtx insn, rtx link, rtx dep_insn, int cost)
{
  /* If the dependence is an anti-dependence, there is no cost.  For an
     output dependence, there is sometimes a cost, but it doesn't seem
     worth handling those few cases.  */

  if (REG_NOTE_KIND (link) != 0)
    return 0;

  /* If we can't recognize the insns, we can't really do anything.  */
  if (recog_memoized (insn) < 0 || recog_memoized (dep_insn) < 0)
    return cost;

  /* Operand forward in case of lr, load and la.  */
  if (s390_tune == PROCESSOR_2084_Z990
      && cost == 1
      && (s390_safe_attr_type (dep_insn) == TYPE_LA
          || s390_safe_attr_type (dep_insn) == TYPE_LR
          || s390_safe_attr_type (dep_insn) == TYPE_LOAD))
    return 0;
  return cost;
}

/* A C statement (sans semicolon) to update the integer scheduling priority
   INSN_PRIORITY (INSN).  Increase the priority to execute the INSN earlier,
   reduce the priority to execute INSN later.  Do not define this macro if
   you do not need to adjust the scheduling priorities of insns.

   A STD instruction should be scheduled earlier,
   in order to use the bypass.  */

static int
s390_adjust_priority (rtx insn ATTRIBUTE_UNUSED, int priority)
{
  if (! INSN_P (insn))
    return priority;

  if (s390_tune != PROCESSOR_2084_Z990)
    return priority;

  switch (s390_safe_attr_type (insn))
    {
      case TYPE_FSTORED:
      case TYPE_FSTORES:
        priority = priority << 3;
        break;
      case TYPE_STORE:
        priority = priority << 1;
        break;
      default:
        break;
    }
  return priority;
}

/* The number of instructions that can be issued per cycle.  */

static int
s390_issue_rate (void)
{
  if (s390_tune == PROCESSOR_2084_Z990)
    return 3;
  return 1;
}

static int
s390_first_cycle_multipass_dfa_lookahead (void)
{
  return 4;
}


/* Split all branches that exceed the maximum distance.
   Returns true if this created a new literal pool entry.  */

static int
s390_split_branches (void)
{
  rtx temp_reg = gen_rtx_REG (Pmode, RETURN_REGNUM);
  int new_literal = 0;
  rtx insn, pat, tmp, target;
  rtx *label;

  /* We need correct insn addresses.  */

  shorten_branches (get_insns ());

  /* Find all branches that exceed 64KB, and split them.  */

  for (insn = get_insns (); insn; insn = NEXT_INSN (insn))
    {
      if (GET_CODE (insn) != JUMP_INSN)
        continue;

      pat = PATTERN (insn);
      if (GET_CODE (pat) == PARALLEL && XVECLEN (pat, 0) > 2)
        pat = XVECEXP (pat, 0, 0);
      if (GET_CODE (pat) != SET || SET_DEST (pat) != pc_rtx)
        continue;

      if (GET_CODE (SET_SRC (pat)) == LABEL_REF)
        {
          label = &SET_SRC (pat);
        }
      else if (GET_CODE (SET_SRC (pat)) == IF_THEN_ELSE)
        {
          if (GET_CODE (XEXP (SET_SRC (pat), 1)) == LABEL_REF)
            label = &XEXP (SET_SRC (pat), 1);
          else if (GET_CODE (XEXP (SET_SRC (pat), 2)) == LABEL_REF)
            label = &XEXP (SET_SRC (pat), 2);
          else
            continue;
        }
      else
        continue;

      if (get_attr_length (insn) <= 4)
        continue;

      /* We are going to use the return register as scratch register,
         make sure it will be saved/restored by the prologue/epilogue.  */
      cfun->machine->save_return_addr_p = 1;

      if (!flag_pic)
        {
          new_literal = 1;
          tmp = force_const_mem (Pmode, *label);
          tmp = emit_insn_before (gen_rtx_SET (Pmode, temp_reg, tmp), insn);
          INSN_ADDRESSES_NEW (tmp, -1);
          annotate_constant_pool_refs (&PATTERN (tmp));

          target = temp_reg;
        }
      else
        {
          new_literal = 1;
          target = gen_rtx_UNSPEC (Pmode, gen_rtvec (1, *label),
                                   UNSPEC_LTREL_OFFSET);
          target = gen_rtx_CONST (Pmode, target);
          target = force_const_mem (Pmode, target);
          tmp = emit_insn_before (gen_rtx_SET (Pmode, temp_reg, target), insn);
          INSN_ADDRESSES_NEW (tmp, -1);
          annotate_constant_pool_refs (&PATTERN (tmp));

          target = gen_rtx_UNSPEC (Pmode, gen_rtvec (2, XEXP (target, 0),
                                                        cfun->machine->base_reg),
                                   UNSPEC_LTREL_BASE);
          target = gen_rtx_PLUS (Pmode, temp_reg, target);
        }

      if (!validate_change (insn, label, target, 0))
        abort ();
    }

  return new_literal;
}

/* Annotate every literal pool reference in X by an UNSPEC_LTREF expression.
   Fix up MEMs as required.  */

static void
annotate_constant_pool_refs (rtx *x)
{
  int i, j;
  const char *fmt;

  if (GET_CODE (*x) == SYMBOL_REF
      && CONSTANT_POOL_ADDRESS_P (*x))
    abort ();

  /* Literal pool references can only occur inside a MEM ...  */
  if (GET_CODE (*x) == MEM)
    {
      rtx memref = XEXP (*x, 0);

      if (GET_CODE (memref) == SYMBOL_REF
          && CONSTANT_POOL_ADDRESS_P (memref))
        {
          rtx base = cfun->machine->base_reg;
          rtx addr = gen_rtx_UNSPEC (Pmode, gen_rtvec (2, memref, base),
                                     UNSPEC_LTREF);

          *x = replace_equiv_address (*x, addr);
          return;
        }

      if (GET_CODE (memref) == CONST
          && GET_CODE (XEXP (memref, 0)) == PLUS
          && GET_CODE (XEXP (XEXP (memref, 0), 1)) == CONST_INT
          && GET_CODE (XEXP (XEXP (memref, 0), 0)) == SYMBOL_REF
          && CONSTANT_POOL_ADDRESS_P (XEXP (XEXP (memref, 0), 0)))
        {
          HOST_WIDE_INT off = INTVAL (XEXP (XEXP (memref, 0), 1));
          rtx sym = XEXP (XEXP (memref, 0), 0);
          rtx base = cfun->machine->base_reg;
          rtx addr = gen_rtx_UNSPEC (Pmode, gen_rtvec (2, sym, base),
                                     UNSPEC_LTREF);

          *x = replace_equiv_address (*x, plus_constant (addr, off));
          return;
        }
    }

  /* ... or a load-address type pattern.  */
  if (GET_CODE (*x) == SET)
    {
      rtx addrref = SET_SRC (*x);

      if (GET_CODE (addrref) == SYMBOL_REF
          && CONSTANT_POOL_ADDRESS_P (addrref))
        {
          rtx base = cfun->machine->base_reg;
          rtx addr = gen_rtx_UNSPEC (Pmode, gen_rtvec (2, addrref, base),
                                     UNSPEC_LTREF);

          SET_SRC (*x) = addr;
          return;
        }

      if (GET_CODE (addrref) == CONST
          && GET_CODE (XEXP (addrref, 0)) == PLUS
          && GET_CODE (XEXP (XEXP (addrref, 0), 1)) == CONST_INT
          && GET_CODE (XEXP (XEXP (addrref, 0), 0)) == SYMBOL_REF
          && CONSTANT_POOL_ADDRESS_P (XEXP (XEXP (addrref, 0), 0)))
        {
          HOST_WIDE_INT off = INTVAL (XEXP (XEXP (addrref, 0), 1));
          rtx sym = XEXP (XEXP (addrref, 0), 0);
          rtx base = cfun->machine->base_reg;
          rtx addr = gen_rtx_UNSPEC (Pmode, gen_rtvec (2, sym, base),
                                     UNSPEC_LTREF);

          SET_SRC (*x) = plus_constant (addr, off);
          return;
        }
    }

  /* Annotate LTREL_BASE as well.  */
  if (GET_CODE (*x) == UNSPEC
      && XINT (*x, 1) == UNSPEC_LTREL_BASE)
    {
      rtx base = cfun->machine->base_reg;
      *x = gen_rtx_UNSPEC (Pmode, gen_rtvec (2, XVECEXP (*x, 0, 0), base),
                                  UNSPEC_LTREL_BASE);
      return;
    }

  fmt = GET_RTX_FORMAT (GET_CODE (*x));
  for (i = GET_RTX_LENGTH (GET_CODE (*x)) - 1; i >= 0; i--)
    {
      if (fmt[i] == 'e')
        {
          annotate_constant_pool_refs (&XEXP (*x, i));
        }
      else if (fmt[i] == 'E')
        {
          for (j = 0; j < XVECLEN (*x, i); j++)
            annotate_constant_pool_refs (&XVECEXP (*x, i, j));
        }
    }
}


/* Find an annotated literal pool symbol referenced in RTX X, 
   and store it at REF.  Will abort if X contains references to 
   more than one such pool symbol; multiple references to the same
   symbol are allowed, however.

   The rtx pointed to by REF must be initialized to NULL_RTX
   by the caller before calling this routine.  */

static void
find_constant_pool_ref (rtx x, rtx *ref)
{
  int i, j;
  const char *fmt;

  /* Ignore LTREL_BASE references.  */
  if (GET_CODE (x) == UNSPEC
      && XINT (x, 1) == UNSPEC_LTREL_BASE)
    return;
  /* Likewise POOL_ENTRY insns.  */
  if (GET_CODE (x) == UNSPEC_VOLATILE
      && XINT (x, 1) == UNSPECV_POOL_ENTRY)
    return;

  if (GET_CODE (x) == SYMBOL_REF
      && CONSTANT_POOL_ADDRESS_P (x))
    abort ();

  if (GET_CODE (x) == UNSPEC && XINT (x, 1) == UNSPEC_LTREF)
    {
      rtx sym = XVECEXP (x, 0, 0);
      if (GET_CODE (sym) != SYMBOL_REF
          || !CONSTANT_POOL_ADDRESS_P (sym))
        abort ();

      if (*ref == NULL_RTX)
        *ref = sym;
      else if (*ref != sym)
        abort ();

      return;
    }

  fmt = GET_RTX_FORMAT (GET_CODE (x));
  for (i = GET_RTX_LENGTH (GET_CODE (x)) - 1; i >= 0; i--)
    {
      if (fmt[i] == 'e')
        {
          find_constant_pool_ref (XEXP (x, i), ref);
        }
      else if (fmt[i] == 'E')
        {
          for (j = 0; j < XVECLEN (x, i); j++)
            find_constant_pool_ref (XVECEXP (x, i, j), ref);
        }
    }
}

/* Replace every reference to the annotated literal pool 
   symbol REF in X by its base plus OFFSET.  */

static void
replace_constant_pool_ref (rtx *x, rtx ref, rtx offset)
{
  int i, j;
  const char *fmt;

  if (*x == ref)
    abort ();

  if (GET_CODE (*x) == UNSPEC
      && XINT (*x, 1) == UNSPEC_LTREF
      && XVECEXP (*x, 0, 0) == ref)
    {
      *x = gen_rtx_PLUS (Pmode, XVECEXP (*x, 0, 1), offset);
      return;
    }

  if (GET_CODE (*x) == PLUS
      && GET_CODE (XEXP (*x, 1)) == CONST_INT
      && GET_CODE (XEXP (*x, 0)) == UNSPEC
      && XINT (XEXP (*x, 0), 1) == UNSPEC_LTREF
      && XVECEXP (XEXP (*x, 0), 0, 0) == ref)
    {
      rtx addr = gen_rtx_PLUS (Pmode, XVECEXP (XEXP (*x, 0), 0, 1), offset);
      *x = plus_constant (addr, INTVAL (XEXP (*x, 1)));
      return;
    }

  fmt = GET_RTX_FORMAT (GET_CODE (*x));
  for (i = GET_RTX_LENGTH (GET_CODE (*x)) - 1; i >= 0; i--)
    {
      if (fmt[i] == 'e')
        {
          replace_constant_pool_ref (&XEXP (*x, i), ref, offset);
        }
      else if (fmt[i] == 'E')
        {
          for (j = 0; j < XVECLEN (*x, i); j++)
            replace_constant_pool_ref (&XVECEXP (*x, i, j), ref, offset);
        }
    }
}

/* Check whether X contains an UNSPEC_LTREL_BASE.
   Return its constant pool symbol if found, NULL_RTX otherwise.  */

static rtx
find_ltrel_base (rtx x)
{
  int i, j;
  const char *fmt;

  if (GET_CODE (x) == UNSPEC
      && XINT (x, 1) == UNSPEC_LTREL_BASE)
    return XVECEXP (x, 0, 0);

  fmt = GET_RTX_FORMAT (GET_CODE (x));
  for (i = GET_RTX_LENGTH (GET_CODE (x)) - 1; i >= 0; i--)
    {
      if (fmt[i] == 'e')
        {
          rtx fnd = find_ltrel_base (XEXP (x, i));
          if (fnd)
            return fnd;
        }
      else if (fmt[i] == 'E')
        {
          for (j = 0; j < XVECLEN (x, i); j++)
            {
              rtx fnd = find_ltrel_base (XVECEXP (x, i, j));
              if (fnd)
                return fnd;
            }
        }
    }

  return NULL_RTX;
}

/* Replace any occurrence of UNSPEC_LTREL_BASE in X with its base.  */

static void
replace_ltrel_base (rtx *x)
{
  int i, j;
  const char *fmt;

  if (GET_CODE (*x) == UNSPEC
      && XINT (*x, 1) == UNSPEC_LTREL_BASE)
    {
      *x = XVECEXP (*x, 0, 1);
      return;
    }

  fmt = GET_RTX_FORMAT (GET_CODE (*x));
  for (i = GET_RTX_LENGTH (GET_CODE (*x)) - 1; i >= 0; i--)
    {
      if (fmt[i] == 'e')
        {
          replace_ltrel_base (&XEXP (*x, i));
        }
      else if (fmt[i] == 'E')
        {
          for (j = 0; j < XVECLEN (*x, i); j++)
            replace_ltrel_base (&XVECEXP (*x, i, j));
        }
    }
}


/* We keep a list of constants which we have to add to internal
   constant tables in the middle of large functions.  */

#define NR_C_MODES 7
enum machine_mode constant_modes[NR_C_MODES] =
{
  TImode,
  DFmode, DImode,
  SFmode, SImode,
  HImode,
  QImode
};

struct constant
{
  struct constant *next;
  rtx value;
  rtx label;
};

struct constant_pool
{
  struct constant_pool *next;
  rtx first_insn;
  rtx pool_insn;
  bitmap insns;

  struct constant *constants[NR_C_MODES];
  rtx label;
  int size;
};

static struct constant_pool * s390_mainpool_start (void);
static void s390_mainpool_finish (struct constant_pool *);
static void s390_mainpool_cancel (struct constant_pool *);

static struct constant_pool * s390_chunkify_start (void);
static void s390_chunkify_finish (struct constant_pool *);
static void s390_chunkify_cancel (struct constant_pool *);

static struct constant_pool *s390_start_pool (struct constant_pool **, rtx);
static void s390_end_pool (struct constant_pool *, rtx);
static void s390_add_pool_insn (struct constant_pool *, rtx);
static struct constant_pool *s390_find_pool (struct constant_pool *, rtx);
static void s390_add_constant (struct constant_pool *, rtx, enum machine_mode);
static rtx s390_find_constant (struct constant_pool *, rtx, enum machine_mode);
static rtx s390_dump_pool (struct constant_pool *, bool);
static struct constant_pool *s390_alloc_pool (void);
static void s390_free_pool (struct constant_pool *);

/* Create new constant pool covering instructions starting at INSN
   and chain it to the end of POOL_LIST.  */

static struct constant_pool *
s390_start_pool (struct constant_pool **pool_list, rtx insn)
{
  struct constant_pool *pool, **prev;

  pool = s390_alloc_pool ();
  pool->first_insn = insn;

  for (prev = pool_list; *prev; prev = &(*prev)->next)
    ;
  *prev = pool;

  return pool;
}

/* End range of instructions covered by POOL at INSN and emit
   placeholder insn representing the pool.  */

static void
s390_end_pool (struct constant_pool *pool, rtx insn)
{
  rtx pool_size = GEN_INT (pool->size + 8 /* alignment slop */);

  if (!insn)
    insn = get_last_insn ();

  pool->pool_insn = emit_insn_after (gen_pool (pool_size), insn);
  INSN_ADDRESSES_NEW (pool->pool_insn, -1);
}

/* Add INSN to the list of insns covered by POOL.  */

static void
s390_add_pool_insn (struct constant_pool *pool, rtx insn)
{
  bitmap_set_bit (pool->insns, INSN_UID (insn));
}

/* Return pool out of POOL_LIST that covers INSN.  */

static struct constant_pool *
s390_find_pool (struct constant_pool *pool_list, rtx insn)
{
  struct constant_pool *pool;

  for (pool = pool_list; pool; pool = pool->next)
    if (bitmap_bit_p (pool->insns, INSN_UID (insn)))
      break;

  return pool;
}

/* Add constant VAL of mode MODE to the constant pool POOL.  */

static void
s390_add_constant (struct constant_pool *pool, rtx val, enum machine_mode mode)
{
  struct constant *c;
  int i;

  for (i = 0; i < NR_C_MODES; i++)
    if (constant_modes[i] == mode)
      break;
  if (i == NR_C_MODES)
    abort ();

  for (c = pool->constants[i]; c != NULL; c = c->next)
    if (rtx_equal_p (val, c->value))
      break;

  if (c == NULL)
    {
      c = (struct constant *) xmalloc (sizeof *c);
      c->value = val;
      c->label = gen_label_rtx ();
      c->next = pool->constants[i];
      pool->constants[i] = c;
      pool->size += GET_MODE_SIZE (mode);
    }
}

/* Find constant VAL of mode MODE in the constant pool POOL.
   Return an RTX describing the distance from the start of
   the pool to the location of the new constant.  */

static rtx
s390_find_constant (struct constant_pool *pool, rtx val,
                    enum machine_mode mode)
{
  struct constant *c;
  rtx offset;
  int i;

  for (i = 0; i < NR_C_MODES; i++)
    if (constant_modes[i] == mode)
      break;
  if (i == NR_C_MODES)
    abort ();

  for (c = pool->constants[i]; c != NULL; c = c->next)
    if (rtx_equal_p (val, c->value))
      break;

  if (c == NULL)
    abort ();

  offset = gen_rtx_MINUS (Pmode, gen_rtx_LABEL_REF (Pmode, c->label),
                                 gen_rtx_LABEL_REF (Pmode, pool->label));
  offset = gen_rtx_CONST (Pmode, offset);
  return offset;
}

/* Dump out the constants in POOL.  If REMOTE_LABEL is true,
   do not emit the pool base label.  */

static rtx
s390_dump_pool (struct constant_pool *pool, bool remote_label)
{
  struct constant *c;
  rtx insn;
  int i;

  /* Pool start insn switches to proper section
     and guarantees necessary alignment.  */
  if (TARGET_CPU_ZARCH)
    insn = emit_insn_after (gen_pool_start_64 (), pool->pool_insn);
  else
    insn = emit_insn_after (gen_pool_start_31 (), pool->pool_insn);
  INSN_ADDRESSES_NEW (insn, -1);

  if (!remote_label)
    {
      insn = emit_label_after (pool->label, insn);
      INSN_ADDRESSES_NEW (insn, -1);
    }

  /* Dump constants in descending alignment requirement order,
     ensuring proper alignment for every constant.  */
  for (i = 0; i < NR_C_MODES; i++)
    for (c = pool->constants[i]; c; c = c->next)
      {
        /* Convert UNSPEC_LTREL_OFFSET unspecs to pool-relative references.  */
        rtx value = c->value;
        if (GET_CODE (value) == CONST
            && GET_CODE (XEXP (value, 0)) == UNSPEC
            && XINT (XEXP (value, 0), 1) == UNSPEC_LTREL_OFFSET
            && XVECLEN (XEXP (value, 0), 0) == 1)
          {
            value = gen_rtx_MINUS (Pmode, XVECEXP (XEXP (value, 0), 0, 0),
                                   gen_rtx_LABEL_REF (VOIDmode, pool->label));
            value = gen_rtx_CONST (VOIDmode, value);
          }

        insn = emit_label_after (c->label, insn);
        INSN_ADDRESSES_NEW (insn, -1);

        value = gen_rtx_UNSPEC_VOLATILE (constant_modes[i],
                                         gen_rtvec (1, value),
                                         UNSPECV_POOL_ENTRY);
        insn = emit_insn_after (value, insn);
        INSN_ADDRESSES_NEW (insn, -1);
      }

  /* Pool end insn switches back to previous section
     and guarantees necessary alignment.  */
  if (TARGET_CPU_ZARCH)
    insn = emit_insn_after (gen_pool_end_64 (), insn);
  else
    insn = emit_insn_after (gen_pool_end_31 (), insn);
  INSN_ADDRESSES_NEW (insn, -1);

  insn = emit_barrier_after (insn);
  INSN_ADDRESSES_NEW (insn, -1);

  /* Remove placeholder insn.  */
  remove_insn (pool->pool_insn);

  return insn;
}

/* Allocate new constant_pool structure.  */

static struct constant_pool *
s390_alloc_pool (void)
{
  struct constant_pool *pool;
  int i;

  pool = (struct constant_pool *) xmalloc (sizeof *pool);
  pool->next = NULL;
  for (i = 0; i < NR_C_MODES; i++)
    pool->constants[i] = NULL;

  pool->label = gen_label_rtx ();
  pool->first_insn = NULL_RTX;
  pool->pool_insn = NULL_RTX;
  pool->insns = BITMAP_XMALLOC ();
  pool->size = 0;

  return pool;
}

/* Free all memory used by POOL.  */

static void
s390_free_pool (struct constant_pool *pool)
{
  int i;

  for (i = 0; i < NR_C_MODES; i++)
    {
      struct constant *c = pool->constants[i];
      while (c != NULL)
        {
          struct constant *next = c->next;
          free (c);
          c = next;
        }
    }

  BITMAP_XFREE (pool->insns);
  free (pool);
}


/* Collect main literal pool.  Return NULL on overflow.  */

static struct constant_pool *
s390_mainpool_start (void)
{
  struct constant_pool *pool;
  rtx insn;

  pool = s390_alloc_pool ();

  for (insn = get_insns (); insn; insn = NEXT_INSN (insn))
    {
      if (GET_CODE (insn) == INSN
          && GET_CODE (PATTERN (insn)) == SET
          && GET_CODE (SET_SRC (PATTERN (insn))) == UNSPEC_VOLATILE
          && XINT (SET_SRC (PATTERN (insn)), 1) == UNSPECV_MAIN_POOL)
        {
          if (pool->pool_insn)
            abort ();
          pool->pool_insn = insn;
        }

      if (GET_CODE (insn) == INSN || GET_CODE (insn) == CALL_INSN)
        {
          rtx pool_ref = NULL_RTX;
          find_constant_pool_ref (PATTERN (insn), &pool_ref);
          if (pool_ref)
            {
              rtx constant = get_pool_constant (pool_ref);
              enum machine_mode mode = get_pool_mode (pool_ref);
              s390_add_constant (pool, constant, mode);
            }
        }
    }

  if (!pool->pool_insn)
    abort ();

  if (pool->size >= 4096)
    {
      /* We're going to chunkify the pool, so remove the main
         pool placeholder insn.  */
      remove_insn (pool->pool_insn);

      s390_free_pool (pool);
      pool = NULL;
    }

  return pool;
}

/* POOL holds the main literal pool as collected by s390_mainpool_start.
   Modify the current function to output the pool constants as well as
   the pool register setup instruction.  */

static void
s390_mainpool_finish (struct constant_pool *pool)
{
  rtx base_reg = SET_DEST (PATTERN (pool->pool_insn));
  rtx insn;

  /* If the pool is empty, we're done.  */
  if (pool->size == 0)
    {
      remove_insn (pool->pool_insn);
      s390_free_pool (pool);
      return;
    }

  /* We need correct insn addresses.  */
  shorten_branches (get_insns ());

  /* On zSeries, we use a LARL to load the pool register.  The pool is
     located in the .rodata section, so we emit it after the function.  */
  if (TARGET_CPU_ZARCH)
    {
      insn = gen_main_base_64 (base_reg, pool->label);
      insn = emit_insn_after (insn, pool->pool_insn);
      INSN_ADDRESSES_NEW (insn, -1);
      remove_insn (pool->pool_insn);

      insn = get_last_insn ();
      pool->pool_insn = emit_insn_after (gen_pool (const0_rtx), insn);
      INSN_ADDRESSES_NEW (pool->pool_insn, -1);

      s390_dump_pool (pool, 0);
    }

  /* On S/390, if the total size of the function's code plus literal pool
     does not exceed 4096 bytes, we use BASR to set up a function base
     pointer, and emit the literal pool at the end of the function.  */
  else if (INSN_ADDRESSES (INSN_UID (get_last_insn ()))
           + pool->size + 8 /* alignment slop */ < 4096)
    {
      insn = gen_main_base_31_small (base_reg, pool->label);
      insn = emit_insn_after (insn, pool->pool_insn);
      INSN_ADDRESSES_NEW (insn, -1);
      remove_insn (pool->pool_insn);

      insn = emit_label_after (pool->label, insn);
      INSN_ADDRESSES_NEW (insn, -1);

      insn = get_last_insn ();
      pool->pool_insn = emit_insn_after (gen_pool (const0_rtx), insn);
      INSN_ADDRESSES_NEW (pool->pool_insn, -1);

      s390_dump_pool (pool, 1);
    }

  /* Otherwise, we emit an inline literal pool and use BASR to branch
     over it, setting up the pool register at the same time.  */
  else
    {
      rtx pool_end = gen_label_rtx ();

      insn = gen_main_base_31_large (base_reg, pool->label, pool_end);
      insn = emit_insn_after (insn, pool->pool_insn);
      INSN_ADDRESSES_NEW (insn, -1);
      remove_insn (pool->pool_insn);

      insn = emit_label_after (pool->label, insn);
      INSN_ADDRESSES_NEW (insn, -1);

      pool->pool_insn = emit_insn_after (gen_pool (const0_rtx), insn);
      INSN_ADDRESSES_NEW (pool->pool_insn, -1);

      insn = emit_label_after (pool_end, pool->pool_insn);
      INSN_ADDRESSES_NEW (insn, -1);

      s390_dump_pool (pool, 1);
    }


  /* Replace all literal pool references.  */

  for (insn = get_insns (); insn; insn = NEXT_INSN (insn))
    {
      if (INSN_P (insn))
        replace_ltrel_base (&PATTERN (insn));

      if (GET_CODE (insn) == INSN || GET_CODE (insn) == CALL_INSN)
        {
          rtx addr, pool_ref = NULL_RTX;
          find_constant_pool_ref (PATTERN (insn), &pool_ref);
          if (pool_ref)
            {
              addr = s390_find_constant (pool, get_pool_constant (pool_ref),
                                               get_pool_mode (pool_ref));
              replace_constant_pool_ref (&PATTERN (insn), pool_ref, addr);
              INSN_CODE (insn) = -1;
            }
        }
    }


  /* Free the pool.  */
  s390_free_pool (pool);
}

/* POOL holds the main literal pool as collected by s390_mainpool_start.
   We have decided we cannot use this pool, so revert all changes
   to the current function that were done by s390_mainpool_start.  */
static void
s390_mainpool_cancel (struct constant_pool *pool)
{
  /* We didn't actually change the instruction stream, so simply
     free the pool memory.  */
  s390_free_pool (pool);
}


/* Chunkify the literal pool.  */

#define S390_POOL_CHUNK_MIN     0xc00
#define S390_POOL_CHUNK_MAX     0xe00

static struct constant_pool *
s390_chunkify_start (void)
{
  struct constant_pool *curr_pool = NULL, *pool_list = NULL;
  int extra_size = 0;
  bitmap far_labels;
  rtx pending_ltrel = NULL_RTX;
  rtx insn;

  rtx (*gen_reload_base) (rtx, rtx) =
    TARGET_CPU_ZARCH? gen_reload_base_64 : gen_reload_base_31;


  /* We need correct insn addresses.  */

  shorten_branches (get_insns ());

  /* Scan all insns and move literals to pool chunks.  */

  for (insn = get_insns (); insn; insn = NEXT_INSN (insn))
    {
      /* Check for pending LTREL_BASE.  */
      if (INSN_P (insn))
        {
          rtx ltrel_base = find_ltrel_base (PATTERN (insn));
          if (ltrel_base)
            {
              if (ltrel_base == pending_ltrel)
                pending_ltrel = NULL_RTX;
              else
                abort ();
            }
        }

      if (GET_CODE (insn) == INSN || GET_CODE (insn) == CALL_INSN)
        {
          rtx pool_ref = NULL_RTX;
          find_constant_pool_ref (PATTERN (insn), &pool_ref);
          if (pool_ref)
            {
              rtx constant = get_pool_constant (pool_ref);
              enum machine_mode mode = get_pool_mode (pool_ref);

              if (!curr_pool)
                curr_pool = s390_start_pool (&pool_list, insn);

              s390_add_constant (curr_pool, constant, mode);
              s390_add_pool_insn (curr_pool, insn);

              /* Don't split the pool chunk between a LTREL_OFFSET load
                 and the corresponding LTREL_BASE.  */
              if (GET_CODE (constant) == CONST
                  && GET_CODE (XEXP (constant, 0)) == UNSPEC
                  && XINT (XEXP (constant, 0), 1) == UNSPEC_LTREL_OFFSET)
                {
                  if (pending_ltrel)
                    abort ();
                  pending_ltrel = pool_ref;
                }
            }
        }

      if (GET_CODE (insn) == JUMP_INSN || GET_CODE (insn) == CODE_LABEL)
        {
          if (curr_pool)
            s390_add_pool_insn (curr_pool, insn);
          /* An LTREL_BASE must follow within the same basic block.  */
          if (pending_ltrel)
            abort ();
        }

      if (!curr_pool
          || INSN_ADDRESSES_SIZE () <= (size_t) INSN_UID (insn)
          || INSN_ADDRESSES (INSN_UID (insn)) == -1)
        continue;

      if (TARGET_CPU_ZARCH)
        {
          if (curr_pool->size < S390_POOL_CHUNK_MAX)
            continue;

          s390_end_pool (curr_pool, NULL_RTX);
          curr_pool = NULL;
        }
      else
        {
          int chunk_size = INSN_ADDRESSES (INSN_UID (insn))
                           - INSN_ADDRESSES (INSN_UID (curr_pool->first_insn))
                         + extra_size;

          /* We will later have to insert base register reload insns.
             Those will have an effect on code size, which we need to
             consider here.  This calculation makes rather pessimistic
             worst-case assumptions.  */
          if (GET_CODE (insn) == CODE_LABEL)
            extra_size += 6;

          if (chunk_size < S390_POOL_CHUNK_MIN
              && curr_pool->size < S390_POOL_CHUNK_MIN)
            continue;

          /* Pool chunks can only be inserted after BARRIERs ...  */
          if (GET_CODE (insn) == BARRIER)
            {
              s390_end_pool (curr_pool, insn);
              curr_pool = NULL;
              extra_size = 0;
            }

          /* ... so if we don't find one in time, create one.  */
          else if ((chunk_size > S390_POOL_CHUNK_MAX
                   || curr_pool->size > S390_POOL_CHUNK_MAX))
            {
              rtx label, jump, barrier;

              /* We can insert the barrier only after a 'real' insn.  */
              if (GET_CODE (insn) != INSN && GET_CODE (insn) != CALL_INSN)
                continue;
              if (get_attr_length (insn) == 0)
                continue;

              /* Don't separate LTREL_BASE from the corresponding
                 LTREL_OFFSET load.  */
              if (pending_ltrel)
                continue;

              label = gen_label_rtx ();
              jump = emit_jump_insn_after (gen_jump (label), insn);
              barrier = emit_barrier_after (jump);
              insn = emit_label_after (label, barrier);
              JUMP_LABEL (jump) = label;
              LABEL_NUSES (label) = 1;

              INSN_ADDRESSES_NEW (jump, -1);
              INSN_ADDRESSES_NEW (barrier, -1);
              INSN_ADDRESSES_NEW (insn, -1);

              s390_end_pool (curr_pool, barrier);
              curr_pool = NULL;
              extra_size = 0;
            }
        }
    }

  if (curr_pool)
    s390_end_pool (curr_pool, NULL_RTX);
  if (pending_ltrel)
    abort ();


  /* Find all labels that are branched into
     from an insn belonging to a different chunk.  */

  far_labels = BITMAP_XMALLOC ();

  for (insn = get_insns (); insn; insn = NEXT_INSN (insn))
    {
      /* Labels marked with LABEL_PRESERVE_P can be target
         of non-local jumps, so we have to mark them.
         The same holds for named labels.

         Don't do that, however, if it is the label before
         a jump table.  */

      if (GET_CODE (insn) == CODE_LABEL
          && (LABEL_PRESERVE_P (insn) || LABEL_NAME (insn)))
        {
          rtx vec_insn = next_real_insn (insn);
          rtx vec_pat = vec_insn && GET_CODE (vec_insn) == JUMP_INSN ?
                        PATTERN (vec_insn) : NULL_RTX;
          if (!vec_pat
              || !(GET_CODE (vec_pat) == ADDR_VEC
                   || GET_CODE (vec_pat) == ADDR_DIFF_VEC))
            bitmap_set_bit (far_labels, CODE_LABEL_NUMBER (insn));
        }

      /* If we have a direct jump (conditional or unconditional)
         or a casesi jump, check all potential targets.  */
      else if (GET_CODE (insn) == JUMP_INSN)
        {
          rtx pat = PATTERN (insn);
          if (GET_CODE (pat) == PARALLEL && XVECLEN (pat, 0) > 2)
            pat = XVECEXP (pat, 0, 0);

          if (GET_CODE (pat) == SET)
            {
              rtx label = JUMP_LABEL (insn);
              if (label)
                {
                  if (s390_find_pool (pool_list, label)
                      != s390_find_pool (pool_list, insn))
                    bitmap_set_bit (far_labels, CODE_LABEL_NUMBER (label));
                }
            }
          else if (GET_CODE (pat) == PARALLEL
                   && XVECLEN (pat, 0) == 2
                   && GET_CODE (XVECEXP (pat, 0, 0)) == SET
                   && GET_CODE (XVECEXP (pat, 0, 1)) == USE
                   && GET_CODE (XEXP (XVECEXP (pat, 0, 1), 0)) == LABEL_REF)
            {
              /* Find the jump table used by this casesi jump.  */
              rtx vec_label = XEXP (XEXP (XVECEXP (pat, 0, 1), 0), 0);
              rtx vec_insn = next_real_insn (vec_label);
              rtx vec_pat = vec_insn && GET_CODE (vec_insn) == JUMP_INSN ?
                            PATTERN (vec_insn) : NULL_RTX;
              if (vec_pat
                  && (GET_CODE (vec_pat) == ADDR_VEC
                      || GET_CODE (vec_pat) == ADDR_DIFF_VEC))
                {
                  int i, diff_p = GET_CODE (vec_pat) == ADDR_DIFF_VEC;

                  for (i = 0; i < XVECLEN (vec_pat, diff_p); i++)
                    {
                      rtx label = XEXP (XVECEXP (vec_pat, diff_p, i), 0);

                      if (s390_find_pool (pool_list, label)
                          != s390_find_pool (pool_list, insn))
                        bitmap_set_bit (far_labels, CODE_LABEL_NUMBER (label));
                    }
                }
            }
        }
    }

  /* Insert base register reload insns before every pool.  */

  for (curr_pool = pool_list; curr_pool; curr_pool = curr_pool->next)
    {
      rtx new_insn = gen_reload_base (cfun->machine->base_reg, 
                                      curr_pool->label);
      rtx insn = curr_pool->first_insn;
      INSN_ADDRESSES_NEW (emit_insn_before (new_insn, insn), -1);
    }

  /* Insert base register reload insns at every far label.  */

  for (insn = get_insns (); insn; insn = NEXT_INSN (insn))
    if (GET_CODE (insn) == CODE_LABEL
        && bitmap_bit_p (far_labels, CODE_LABEL_NUMBER (insn)))
      {
        struct constant_pool *pool = s390_find_pool (pool_list, insn);
        if (pool)
          {
            rtx new_insn = gen_reload_base (cfun->machine->base_reg, 
                                            pool->label);
            INSN_ADDRESSES_NEW (emit_insn_after (new_insn, insn), -1);
          }
      }


  BITMAP_XFREE (far_labels);


  /* Recompute insn addresses.  */

  init_insn_lengths ();
  shorten_branches (get_insns ());

  return pool_list;
}

/* POOL_LIST is a chunk list as prepared by s390_chunkify_start.
   After we have decided to use this list, finish implementing
   all changes to the current function as required.  */

static void
s390_chunkify_finish (struct constant_pool *pool_list)
{
  struct constant_pool *curr_pool = NULL;
  rtx insn;


  /* Replace all literal pool references.  */

  for (insn = get_insns (); insn; insn = NEXT_INSN (insn))
    {
      if (INSN_P (insn))
        replace_ltrel_base (&PATTERN (insn));

      curr_pool = s390_find_pool (pool_list, insn);
      if (!curr_pool)
        continue;

      if (GET_CODE (insn) == INSN || GET_CODE (insn) == CALL_INSN)
        {
          rtx addr, pool_ref = NULL_RTX;
          find_constant_pool_ref (PATTERN (insn), &pool_ref);
          if (pool_ref)
            {
              addr = s390_find_constant (curr_pool, get_pool_constant (pool_ref),
                                                    get_pool_mode (pool_ref));
              replace_constant_pool_ref (&PATTERN (insn), pool_ref, addr);
              INSN_CODE (insn) = -1;
            }
        }
    }

  /* Dump out all literal pools.  */

  for (curr_pool = pool_list; curr_pool; curr_pool = curr_pool->next)
    s390_dump_pool (curr_pool, 0);

  /* Free pool list.  */

  while (pool_list)
    {
      struct constant_pool *next = pool_list->next;
      s390_free_pool (pool_list);
      pool_list = next;
    }
}

/* POOL_LIST is a chunk list as prepared by s390_chunkify_start.
   We have decided we cannot use this list, so revert all changes
   to the current function that were done by s390_chunkify_start.  */

static void
s390_chunkify_cancel (struct constant_pool *pool_list)
{
  struct constant_pool *curr_pool = NULL;
  rtx insn;

  /* Remove all pool placeholder insns.  */

  for (curr_pool = pool_list; curr_pool; curr_pool = curr_pool->next)
    {
      /* Did we insert an extra barrier?  Remove it.  */
      rtx barrier = PREV_INSN (curr_pool->pool_insn);
      rtx jump = barrier? PREV_INSN (barrier) : NULL_RTX;
      rtx label = NEXT_INSN (curr_pool->pool_insn);

      if (jump && GET_CODE (jump) == JUMP_INSN
          && barrier && GET_CODE (barrier) == BARRIER
          && label && GET_CODE (label) == CODE_LABEL
          && GET_CODE (PATTERN (jump)) == SET
          && SET_DEST (PATTERN (jump)) == pc_rtx
          && GET_CODE (SET_SRC (PATTERN (jump))) == LABEL_REF
          && XEXP (SET_SRC (PATTERN (jump)), 0) == label)
        {
          remove_insn (jump);
          remove_insn (barrier);
          remove_insn (label);
        }

      remove_insn (curr_pool->pool_insn);
    }

  /* Remove all base register reload insns.  */

  for (insn = get_insns (); insn; )
    {
      rtx next_insn = NEXT_INSN (insn);

      if (GET_CODE (insn) == INSN
          && GET_CODE (PATTERN (insn)) == SET
          && GET_CODE (SET_SRC (PATTERN (insn))) == UNSPEC
          && XINT (SET_SRC (PATTERN (insn)), 1) == UNSPEC_RELOAD_BASE)
        remove_insn (insn);

      insn = next_insn;
    }

  /* Free pool list.  */

  while (pool_list)
    {
      struct constant_pool *next = pool_list->next;
      s390_free_pool (pool_list);
      pool_list = next;
    }
}


/* Output the constant pool entry EXP in mode MODE with alignment ALIGN.  */

void
s390_output_pool_entry (rtx exp, enum machine_mode mode, unsigned int align)
{
  REAL_VALUE_TYPE r;

  switch (GET_MODE_CLASS (mode))
    {
    case MODE_FLOAT:
      if (GET_CODE (exp) != CONST_DOUBLE)
        abort ();

      REAL_VALUE_FROM_CONST_DOUBLE (r, exp);
      assemble_real (r, mode, align);
      break;

    case MODE_INT:
      assemble_integer (exp, GET_MODE_SIZE (mode), align, 1);
      break;

    default:
      abort ();
    }
}


/* Rework the prolog/epilog to avoid saving/restoring
   registers unnecessarily.  BASE_USED specifies whether
   the literal pool base register needs to be saved.  */

static void
s390_optimize_prolog (bool base_used)
{
  rtx insn, new_insn, next_insn;

  /* Do a final recompute of the frame-related data.  */

  s390_frame_info (base_used, cfun->machine->save_return_addr_p);
  regs_ever_live[BASE_REGISTER] = base_used;
  regs_ever_live[RETURN_REGNUM] = cfun->machine->save_return_addr_p;
  regs_ever_live[STACK_POINTER_REGNUM] = cfun->machine->frame_size > 0;

  /* If all special registers are in fact used, there's nothing we
     can do, so no point in walking the insn list.  */

  if (cfun->machine->first_save_gpr <= BASE_REGISTER 
      && cfun->machine->last_save_gpr >= BASE_REGISTER
      && (TARGET_CPU_ZARCH 
          || (cfun->machine->first_save_gpr <= RETURN_REGNUM 
              && cfun->machine->last_save_gpr >= RETURN_REGNUM)))
    return;

  /* Search for prolog/epilog insns and replace them.  */

  for (insn = get_insns (); insn; insn = next_insn)
    {
      int first, last, off;
      rtx set, base, offset;

      next_insn = NEXT_INSN (insn);

      if (GET_CODE (insn) != INSN)
        continue;

      if (GET_CODE (PATTERN (insn)) == PARALLEL
          && store_multiple_operation (PATTERN (insn), VOIDmode))
        {
          set = XVECEXP (PATTERN (insn), 0, 0);
          first = REGNO (SET_SRC (set));
          last = first + XVECLEN (PATTERN (insn), 0) - 1;
          offset = const0_rtx;
          base = eliminate_constant_term (XEXP (SET_DEST (set), 0), &offset);
          off = INTVAL (offset) - first * UNITS_PER_WORD;

          if (GET_CODE (base) != REG || off < 0)
            continue;
          if (first > BASE_REGISTER || last < BASE_REGISTER)
            continue;

          if (cfun->machine->first_save_gpr != -1)
            {
              new_insn = save_gprs (base, off, cfun->machine->first_save_gpr,
                                    cfun->machine->last_save_gpr);
              new_insn = emit_insn_before (new_insn, insn);
              INSN_ADDRESSES_NEW (new_insn, -1);
            }

          remove_insn (insn);
          continue;
        }

      if (GET_CODE (PATTERN (insn)) == SET
          && GET_CODE (SET_SRC (PATTERN (insn))) == REG
          && REGNO (SET_SRC (PATTERN (insn))) == BASE_REGISTER
          && GET_CODE (SET_DEST (PATTERN (insn))) == MEM)
        {
          set = PATTERN (insn);
          offset = const0_rtx;
          base = eliminate_constant_term (XEXP (SET_DEST (set), 0), &offset);
          off = INTVAL (offset) - BASE_REGISTER * UNITS_PER_WORD;

          if (GET_CODE (base) != REG || off < 0)
            continue;

          if (cfun->machine->first_save_gpr != -1)
            {
              new_insn = save_gprs (base, off, cfun->machine->first_save_gpr,
                                    cfun->machine->last_save_gpr);
              new_insn = emit_insn_before (new_insn, insn);
              INSN_ADDRESSES_NEW (new_insn, -1);
            }

          remove_insn (insn);
          continue;
        }

      if (GET_CODE (PATTERN (insn)) == PARALLEL
          && load_multiple_operation (PATTERN (insn), VOIDmode))
        {
          set = XVECEXP (PATTERN (insn), 0, 0);
          first = REGNO (SET_DEST (set));
          last = first + XVECLEN (PATTERN (insn), 0) - 1;
          offset = const0_rtx;
          base = eliminate_constant_term (XEXP (SET_SRC (set), 0), &offset);
          off = INTVAL (offset) - first * UNITS_PER_WORD;

          if (GET_CODE (base) != REG || off < 0)
            continue;
          if (first > BASE_REGISTER || last < BASE_REGISTER)
            continue;

          if (cfun->machine->first_restore_gpr != -1)
            {
              new_insn = restore_gprs (base, off, cfun->machine->first_restore_gpr,
                                       cfun->machine->last_restore_gpr);
              new_insn = emit_insn_before (new_insn, insn);
              INSN_ADDRESSES_NEW (new_insn, -1);
            }

          remove_insn (insn);
          continue;
        }

      if (GET_CODE (PATTERN (insn)) == SET
          && GET_CODE (SET_DEST (PATTERN (insn))) == REG
          && REGNO (SET_DEST (PATTERN (insn))) == BASE_REGISTER
          && GET_CODE (SET_SRC (PATTERN (insn))) == MEM)
        {
          set = PATTERN (insn);
          offset = const0_rtx;
          base = eliminate_constant_term (XEXP (SET_SRC (set), 0), &offset);
          off = INTVAL (offset) - BASE_REGISTER * UNITS_PER_WORD;

          if (GET_CODE (base) != REG || off < 0)
            continue;

          if (cfun->machine->first_restore_gpr != -1)
            {
              new_insn = restore_gprs (base, off, cfun->machine->first_restore_gpr,
                                       cfun->machine->last_restore_gpr);
              new_insn = emit_insn_before (new_insn, insn);
              INSN_ADDRESSES_NEW (new_insn, -1);
            }

          remove_insn (insn);
          continue;
        }
    }
}

/* Perform machine-dependent processing.  */

static void
s390_reorg (void)
{
  bool base_used = false;
  bool pool_overflow = false;

  /* Make sure all splits have been performed; splits after
     machine_dependent_reorg might confuse insn length counts.  */
  split_all_insns_noflow ();


  /* Install the main literal pool and the associated base
     register load insns.

     In addition, there are two problematic situations we need
     to correct:

     - the literal pool might be > 4096 bytes in size, so that
       some of its elements cannot be directly accessed

     - a branch target might be > 64K away from the branch, so that
       it is not possible to use a PC-relative instruction.

     To fix those, we split the single literal pool into multiple
     pool chunks, reloading the pool base register at various
     points throughout the function to ensure it always points to
     the pool chunk the following code expects, and / or replace
     PC-relative branches by absolute branches.

     However, the two problems are interdependent: splitting the
     literal pool can move a branch further away from its target,
     causing the 64K limit to overflow, and on the other hand,
     replacing a PC-relative branch by an absolute branch means
     we need to put the branch target address into the literal
     pool, possibly causing it to overflow.

     So, we loop trying to fix up both problems until we manage
     to satisfy both conditions at the same time.  Note that the
     loop is guaranteed to terminate as every pass of the loop
     strictly decreases the total number of PC-relative branches
     in the function.  (This is not completely true as there
     might be branch-over-pool insns introduced by chunkify_start.
     Those never need to be split however.)  */

  for (;;)
    {
      struct constant_pool *pool = NULL;

      /* Collect the literal pool.  */
      if (!pool_overflow)
        {
          pool = s390_mainpool_start ();
          if (!pool)
            pool_overflow = true;
        }

      /* If literal pool overflowed, start to chunkify it.  */
      if (pool_overflow)
        pool = s390_chunkify_start ();

      /* Split out-of-range branches.  If this has created new
         literal pool entries, cancel current chunk list and
         recompute it.  zSeries machines have large branch
         instructions, so we never need to split a branch.  */
      if (!TARGET_CPU_ZARCH && s390_split_branches ())
        {
          if (pool_overflow)
            s390_chunkify_cancel (pool);
          else
            s390_mainpool_cancel (pool);

          continue;
        }

      /* If we made it up to here, both conditions are satisfied.
         Finish up literal pool related changes.  */
      if ((pool_overflow || pool->size > 0)
           && REGNO (cfun->machine->base_reg) == BASE_REGISTER)
        base_used = true;

      if (pool_overflow)
        s390_chunkify_finish (pool);
      else
        s390_mainpool_finish (pool);

      break;
    }

  s390_optimize_prolog (base_used);
}


/* Return an RTL expression representing the value of the return address
   for the frame COUNT steps up from the current frame.  FRAME is the
   frame pointer of that frame.  */

rtx
s390_return_addr_rtx (int count, rtx frame)
{
  rtx addr;

  /* Without backchain, we fail for all but the current frame.  */

  if (!TARGET_BACKCHAIN && count > 0)
    return NULL_RTX;

  /* For the current frame, we need to make sure the initial
     value of RETURN_REGNUM is actually saved.  */

  if (count == 0)
    cfun->machine->save_return_addr_p = true;

  /* To retrieve the return address we read the stack slot where the
     corresponding RETURN_REGNUM value was saved.  */

  addr = plus_constant (frame, RETURN_REGNUM * UNITS_PER_WORD);
  addr = memory_address (Pmode, addr);
  return gen_rtx_MEM (Pmode, addr);
}

/* Find first call clobbered register unused in a function.
   This could be used as base register in a leaf function
   or for holding the return address before epilogue.  */

static int
find_unused_clobbered_reg (void)
{
  int i;
  for (i = 0; i < 6; i++)
    if (!regs_ever_live[i])
      return i;
  return 0;
}

/* Fill cfun->machine with info about frame of current function.  
   BASE_USED and RETURN_ADDR_USED specify whether we assume the
   base and return address register will need to be saved.  */

static void
s390_frame_info (int base_used, int return_addr_used)
{
  int live_regs[16];
  int i, j;
  HOST_WIDE_INT fsize = get_frame_size ();

  if (!TARGET_64BIT && fsize > 0x7fff0000)
    fatal_error ("Total size of local variables exceeds architecture limit.");

  /* fprs 8 - 15 are caller saved for 64 Bit ABI.  */
  cfun->machine->save_fprs_p = 0;
  if (TARGET_64BIT)
    for (i = 24; i < 32; i++)
      if (regs_ever_live[i] && !global_regs[i])
        {
          cfun->machine->save_fprs_p = 1;
          break;
        }

  cfun->machine->frame_size = fsize + cfun->machine->save_fprs_p * 64;

  /* Does function need to setup frame and save area.  */

  if (!current_function_is_leaf
      || TARGET_TPF_PROFILING
      || cfun->machine->frame_size > 0
      || current_function_calls_alloca
      || current_function_stdarg)
    cfun->machine->frame_size += STARTING_FRAME_OFFSET;

  /* Find first and last gpr to be saved.  We trust regs_ever_live
     data, except that we don't save and restore global registers.

     Also, all registers with special meaning to the compiler need
     to be handled extra.  */

  for (i = 0; i < 16; i++)
    live_regs[i] = regs_ever_live[i] && !global_regs[i];

  if (flag_pic)
    live_regs[PIC_OFFSET_TABLE_REGNUM] = 
    regs_ever_live[PIC_OFFSET_TABLE_REGNUM];

  live_regs[BASE_REGISTER] = base_used;
  live_regs[RETURN_REGNUM] = return_addr_used;
  live_regs[STACK_POINTER_REGNUM] = cfun->machine->frame_size > 0;

  for (i = 6; i < 16; i++)
    if (live_regs[i])
      break;
  for (j = 15; j > i; j--)
    if (live_regs[j])
      break;

  if (i == 16)
    {
      /* Nothing to save/restore.  */
      cfun->machine->first_save_gpr = -1;
      cfun->machine->first_restore_gpr = -1;
      cfun->machine->last_save_gpr = -1;
      cfun->machine->last_restore_gpr = -1;
    }
  else
    {
      /* Save / Restore from gpr i to j.  */
      cfun->machine->first_save_gpr = i;
      cfun->machine->first_restore_gpr = i;
      cfun->machine->last_save_gpr = j;
      cfun->machine->last_restore_gpr = j;
    }

  /* Varargs functions need to save gprs 2 to 6.  */
  if (current_function_stdarg)
    {
      if (cfun->machine->first_save_gpr == -1
          || cfun->machine->first_save_gpr > 2)
        cfun->machine->first_save_gpr = 2;

      if (cfun->machine->last_save_gpr == -1
          || cfun->machine->last_save_gpr < 6)
        cfun->machine->last_save_gpr = 6;
    }
}

/* Return offset between argument pointer and frame pointer
   initially after prologue.  */

HOST_WIDE_INT
s390_arg_frame_offset (void)
{
  /* See the comment in s390_emit_prologue about the assumptions we make
     whether or not the base and return address register need to be saved.  */
  int return_addr_used = !current_function_is_leaf
                         || TARGET_TPF_PROFILING
                         || regs_ever_live[RETURN_REGNUM]
                         || cfun->machine->save_return_addr_p;

  s390_frame_info (1, !TARGET_CPU_ZARCH || return_addr_used);
  return cfun->machine->frame_size + STACK_POINTER_OFFSET;
}

/* Emit insn to save fpr REGNUM at offset OFFSET relative
   to register BASE.  Return generated insn.  */

static rtx
save_fpr (rtx base, int offset, int regnum)
{
  rtx addr;
  addr = gen_rtx_MEM (DFmode, plus_constant (base, offset));
  set_mem_alias_set (addr, s390_sr_alias_set);

  return emit_move_insn (addr, gen_rtx_REG (DFmode, regnum));
}

/* Emit insn to restore fpr REGNUM from offset OFFSET relative
   to register BASE.  Return generated insn.  */

static rtx
restore_fpr (rtx base, int offset, int regnum)
{
  rtx addr;
  addr = gen_rtx_MEM (DFmode, plus_constant (base, offset));
  set_mem_alias_set (addr, s390_sr_alias_set);

  return emit_move_insn (gen_rtx_REG (DFmode, regnum), addr);
}

/* Generate insn to save registers FIRST to LAST into
   the register save area located at offset OFFSET
   relative to register BASE.  */

static rtx
save_gprs (rtx base, int offset, int first, int last)
{
  rtx addr, insn, note;
  int i;

  addr = plus_constant (base, offset + first * UNITS_PER_WORD);
  addr = gen_rtx_MEM (Pmode, addr);
  set_mem_alias_set (addr, s390_sr_alias_set);

  /* Special-case single register.  */
  if (first == last)
    {
      if (TARGET_64BIT)
        insn = gen_movdi (addr, gen_rtx_REG (Pmode, first));
      else
        insn = gen_movsi (addr, gen_rtx_REG (Pmode, first));

      RTX_FRAME_RELATED_P (insn) = 1;
      return insn;
    }


  insn = gen_store_multiple (addr,
                             gen_rtx_REG (Pmode, first),
                             GEN_INT (last - first + 1));


  /* We need to set the FRAME_RELATED flag on all SETs
     inside the store-multiple pattern.

     However, we must not emit DWARF records for registers 2..5
     if they are stored for use by variable arguments ...

     ??? Unfortunately, it is not enough to simply not the the
     FRAME_RELATED flags for those SETs, because the first SET
     of the PARALLEL is always treated as if it had the flag
     set, even if it does not.  Therefore we emit a new pattern
     without those registers as REG_FRAME_RELATED_EXPR note.  */

  if (first >= 6)
    {
      rtx pat = PATTERN (insn);

      for (i = 0; i < XVECLEN (pat, 0); i++)
        if (GET_CODE (XVECEXP (pat, 0, i)) == SET)
          RTX_FRAME_RELATED_P (XVECEXP (pat, 0, i)) = 1;

      RTX_FRAME_RELATED_P (insn) = 1;
    }
  else if (last >= 6)
    {
      addr = plus_constant (base, offset + 6 * UNITS_PER_WORD);
      note = gen_store_multiple (gen_rtx_MEM (Pmode, addr),
                                 gen_rtx_REG (Pmode, 6),
                                 GEN_INT (last - 6 + 1));
      note = PATTERN (note);

      REG_NOTES (insn) =
        gen_rtx_EXPR_LIST (REG_FRAME_RELATED_EXPR,
                           note, REG_NOTES (insn));

      for (i = 0; i < XVECLEN (note, 0); i++)
        if (GET_CODE (XVECEXP (note, 0, i)) == SET)
          RTX_FRAME_RELATED_P (XVECEXP (note, 0, i)) = 1;

      RTX_FRAME_RELATED_P (insn) = 1;
    }

  return insn;
}

/* Generate insn to restore registers FIRST to LAST from
   the register save area located at offset OFFSET
   relative to register BASE.  */

static rtx
restore_gprs (rtx base, int offset, int first, int last)
{
  rtx addr, insn;

  addr = plus_constant (base, offset + first * UNITS_PER_WORD);
  addr = gen_rtx_MEM (Pmode, addr);
  set_mem_alias_set (addr, s390_sr_alias_set);

  /* Special-case single register.  */
  if (first == last)
    {
      if (TARGET_64BIT)
        insn = gen_movdi (gen_rtx_REG (Pmode, first), addr);
      else
        insn = gen_movsi (gen_rtx_REG (Pmode, first), addr);

      return insn;
    }

  insn = gen_load_multiple (gen_rtx_REG (Pmode, first),
                            addr,
                            GEN_INT (last - first + 1));
  return insn;
}

/* Return insn sequence to load the GOT register.  */

static GTY(()) rtx got_symbol;
rtx
s390_load_got (void)
{
  rtx insns;

  if (!got_symbol)
    {
      got_symbol = gen_rtx_SYMBOL_REF (Pmode, "_GLOBAL_OFFSET_TABLE_");
      SYMBOL_REF_FLAGS (got_symbol) = SYMBOL_FLAG_LOCAL;
    }

  start_sequence ();

  if (TARGET_CPU_ZARCH)
    {
      emit_move_insn (pic_offset_table_rtx, got_symbol);
    }
  else
    {
      rtx offset;

      offset = gen_rtx_UNSPEC (Pmode, gen_rtvec (1, got_symbol),
                               UNSPEC_LTREL_OFFSET);
      offset = gen_rtx_CONST (Pmode, offset);
      offset = force_const_mem (Pmode, offset);

      emit_move_insn (pic_offset_table_rtx, offset);

      offset = gen_rtx_UNSPEC (Pmode, gen_rtvec (1, XEXP (offset, 0)),
                               UNSPEC_LTREL_BASE);
      offset = gen_rtx_PLUS (Pmode, pic_offset_table_rtx, offset);

      emit_move_insn (pic_offset_table_rtx, offset);
    }

  insns = get_insns ();
  end_sequence ();
  return insns;
}

/* Expand the prologue into a bunch of separate insns.  */

void
s390_emit_prologue (void)
{
  rtx insn, addr;
  rtx temp_reg;
  int i;

  /* At this point, we decide whether we'll need to save/restore the
     return address register.  This decision is final on zSeries machines;
     on S/390 it can still be overridden in s390_split_branches.  */

  if (!current_function_is_leaf
      || TARGET_TPF_PROFILING
      || regs_ever_live[RETURN_REGNUM])
    cfun->machine->save_return_addr_p = 1;

  /* Decide which register to use as literal pool base.  In small leaf 
     functions, try to use an unused call-clobbered register as base 
     register to avoid save/restore overhead.  */

  if (current_function_is_leaf && !regs_ever_live[5])
    cfun->machine->base_reg = gen_rtx_REG (Pmode, 5);
  else
    cfun->machine->base_reg = gen_rtx_REG (Pmode, BASE_REGISTER);

  regs_ever_live[REGNO (cfun->machine->base_reg)] = 1;

  /* Compute frame info.  Note that at this point, we assume the base 
     register and -on S/390- the return register always need to be saved.
     This is done because the usage of these registers might change even 
     after the prolog was emitted.  If it turns out later that we really 
     don't need them, the prolog/epilog code is modified again.  */

  s390_frame_info (1, !TARGET_CPU_ZARCH || cfun->machine->save_return_addr_p);

  /* We need to update regs_ever_live to avoid data-flow problems.  */

  regs_ever_live[BASE_REGISTER] = 1;
  regs_ever_live[RETURN_REGNUM] = !TARGET_CPU_ZARCH 
                                  || cfun->machine->save_return_addr_p;
  regs_ever_live[STACK_POINTER_REGNUM] = cfun->machine->frame_size > 0;

  /* Annotate all constant pool references to let the scheduler know
     they implicitly use the base register.  */

  push_topmost_sequence ();

  for (insn = get_insns (); insn; insn = NEXT_INSN (insn))
    if (INSN_P (insn))
      annotate_constant_pool_refs (&PATTERN (insn));

  pop_topmost_sequence ();

  /* Choose best register to use for temp use within prologue.
     See below for why TPF must use the register 1.  */

  if (!current_function_is_leaf
      && !TARGET_TPF_PROFILING)
    temp_reg = gen_rtx_REG (Pmode, RETURN_REGNUM);
  else
    temp_reg = gen_rtx_REG (Pmode, 1);

  /* Save call saved gprs.  */

  insn = save_gprs (stack_pointer_rtx, 0,
                    cfun->machine->first_save_gpr, cfun->machine->last_save_gpr);
  emit_insn (insn);

  /* Dummy insn to mark literal pool slot.  */

  emit_insn (gen_main_pool (cfun->machine->base_reg));

  /* Save fprs for variable args.  */

  if (current_function_stdarg)
    for (i = 16; i < (TARGET_64BIT ? 20 : 18); i++)
      save_fpr (stack_pointer_rtx, 16*UNITS_PER_WORD + 8*(i-16), i);

  /* Save fprs 4 and 6 if used (31 bit ABI).  */

  if (!TARGET_64BIT)
    for (i = 18; i < 20; i++)
      if (regs_ever_live[i] && !global_regs[i])
        {
          insn = save_fpr (stack_pointer_rtx, 16*UNITS_PER_WORD + 8*(i-16), i);
          RTX_FRAME_RELATED_P (insn) = 1;
        }

  /* Decrement stack pointer.  */

  if (cfun->machine->frame_size > 0)
    {
      rtx frame_off = GEN_INT (-cfun->machine->frame_size);

      /* Save incoming stack pointer into temp reg.  */

      if (TARGET_BACKCHAIN || cfun->machine->save_fprs_p)
        {
          insn = emit_insn (gen_move_insn (temp_reg, stack_pointer_rtx));
        }

      /* Subtract frame size from stack pointer.  */

      if (DISP_IN_RANGE (INTVAL (frame_off)))
        {
          insn = gen_rtx_SET (VOIDmode, stack_pointer_rtx,
                              gen_rtx_PLUS (Pmode, stack_pointer_rtx,
                                            frame_off));
          insn = emit_insn (insn);
        }
      else
        {
          if (!CONST_OK_FOR_CONSTRAINT_P (INTVAL (frame_off), 'K', "K"))
            frame_off = force_const_mem (Pmode, frame_off);

          insn = emit_insn (gen_add2_insn (stack_pointer_rtx, frame_off));
          annotate_constant_pool_refs (&PATTERN (insn));
        }

      RTX_FRAME_RELATED_P (insn) = 1;
      REG_NOTES (insn) =
        gen_rtx_EXPR_LIST (REG_FRAME_RELATED_EXPR,
                           gen_rtx_SET (VOIDmode, stack_pointer_rtx,
                                   gen_rtx_PLUS (Pmode, stack_pointer_rtx,
                                   GEN_INT (-cfun->machine->frame_size))),
                           REG_NOTES (insn));

      /* Set backchain.  */

      if (TARGET_BACKCHAIN)
        {
          addr = gen_rtx_MEM (Pmode, stack_pointer_rtx);
          set_mem_alias_set (addr, s390_sr_alias_set);
          insn = emit_insn (gen_move_insn (addr, temp_reg));
        }

      /* If we support asynchronous exceptions (e.g. for Java),
         we need to make sure the backchain pointer is set up
         before any possibly trapping memory access.  */

      if (TARGET_BACKCHAIN && flag_non_call_exceptions)
        {
          addr = gen_rtx_MEM (BLKmode, gen_rtx_SCRATCH (VOIDmode));
          emit_insn (gen_rtx_CLOBBER (VOIDmode, addr));
        }
    }

  /* Save fprs 8 - 15 (64 bit ABI).  */

  if (cfun->machine->save_fprs_p)
    {
      insn = emit_insn (gen_add2_insn (temp_reg, GEN_INT(-64)));

      for (i = 24; i < 32; i++)
        if (regs_ever_live[i] && !global_regs[i])
          {
            rtx addr = plus_constant (stack_pointer_rtx,
                                      cfun->machine->frame_size - 64 + (i-24)*8);

            insn = save_fpr (temp_reg, (i-24)*8, i);
            RTX_FRAME_RELATED_P (insn) = 1;
            REG_NOTES (insn) =
              gen_rtx_EXPR_LIST (REG_FRAME_RELATED_EXPR,
                gen_rtx_SET (VOIDmode,
                             gen_rtx_MEM (DFmode, addr),
                             gen_rtx_REG (DFmode, i)),
                REG_NOTES (insn));
          }
    }

  /* Set frame pointer, if needed.  */

  if (frame_pointer_needed)
    {
      insn = emit_move_insn (hard_frame_pointer_rtx, stack_pointer_rtx);
      RTX_FRAME_RELATED_P (insn) = 1;
    }

  /* Set up got pointer, if needed.  */

  if (flag_pic && regs_ever_live[PIC_OFFSET_TABLE_REGNUM])
    {
      rtx insns = s390_load_got ();

      for (insn = insns; insn; insn = NEXT_INSN (insn))
        {
          annotate_constant_pool_refs (&PATTERN (insn));

          REG_NOTES (insn) = gen_rtx_EXPR_LIST (REG_MAYBE_DEAD, NULL_RTX,
                                                REG_NOTES (insn));
        }

      emit_insn (insns);
    }

  if (TARGET_TPF_PROFILING)
    {
      /* Generate a BAS instruction to serve as a function
         entry intercept to facilitate the use of tracing
         algorithms located at the branch target.  */
      emit_insn (gen_prologue_tpf ());

      /* Emit a blockage here so that all code
         lies between the profiling mechanisms.  */
      emit_insn (gen_blockage ());
    }
}

/* Expand the epilogue into a bunch of separate insns.  */

void
s390_emit_epilogue (bool sibcall)
{
  rtx frame_pointer, return_reg;
  int area_bottom, area_top, offset = 0;
  rtvec p;
  int i;

  if (TARGET_TPF_PROFILING)
    {

      /* Generate a BAS instruction to serve as a function
         entry intercept to facilitate the use of tracing
         algorithms located at the branch target.  */

      /* Emit a blockage here so that all code
         lies between the profiling mechanisms.  */
      emit_insn (gen_blockage ());

      emit_insn (gen_epilogue_tpf ());
    }

  /* Check whether to use frame or stack pointer for restore.  */

  frame_pointer = frame_pointer_needed ?
    hard_frame_pointer_rtx : stack_pointer_rtx;

  /* Compute which parts of the save area we need to access.  */

  if (cfun->machine->first_restore_gpr != -1)
    {
      area_bottom = cfun->machine->first_restore_gpr * UNITS_PER_WORD;
      area_top = (cfun->machine->last_restore_gpr + 1) * UNITS_PER_WORD;
    }
  else
    {
      area_bottom = INT_MAX;
      area_top = INT_MIN;
    }

  if (TARGET_64BIT)
    {
      if (cfun->machine->save_fprs_p)
        {
          if (area_bottom > -64)
            area_bottom = -64;
          if (area_top < 0)
            area_top = 0;
        }
    }
  else
    {
      for (i = 18; i < 20; i++)
        if (regs_ever_live[i] && !global_regs[i])
          {
            if (area_bottom > 16*UNITS_PER_WORD + 8*(i-16))
              area_bottom = 16*UNITS_PER_WORD + 8*(i-16);
            if (area_top < 16*UNITS_PER_WORD + 8*(i-16) + 8)
              area_top = 16*UNITS_PER_WORD + 8*(i-16) + 8;
          }
    }

  /* Check whether we can access the register save area.
     If not, increment the frame pointer as required.  */

  if (area_top <= area_bottom)
    {
      /* Nothing to restore.  */
    }
  else if (DISP_IN_RANGE (cfun->machine->frame_size + area_bottom)
           && DISP_IN_RANGE (cfun->machine->frame_size + area_top-1))
    {
      /* Area is in range.  */
      offset = cfun->machine->frame_size;
    }
  else
    {
      rtx insn, frame_off;

      offset = area_bottom < 0 ? -area_bottom : 0;
      frame_off = GEN_INT (cfun->machine->frame_size - offset);

      if (DISP_IN_RANGE (INTVAL (frame_off)))
        {
          insn = gen_rtx_SET (VOIDmode, frame_pointer,
                              gen_rtx_PLUS (Pmode, frame_pointer, frame_off));
          insn = emit_insn (insn);
        }
      else
        {
          if (!CONST_OK_FOR_CONSTRAINT_P (INTVAL (frame_off), 'K', "K"))
            frame_off = force_const_mem (Pmode, frame_off);

          insn = emit_insn (gen_add2_insn (frame_pointer, frame_off));
          annotate_constant_pool_refs (&PATTERN (insn));
        }
    }

  /* Restore call saved fprs.  */

  if (TARGET_64BIT)
    {
      if (cfun->machine->save_fprs_p)
        for (i = 24; i < 32; i++)
          if (regs_ever_live[i] && !global_regs[i])
            restore_fpr (frame_pointer,
                         offset - 64 + (i-24) * 8, i);
    }
  else
    {
      for (i = 18; i < 20; i++)
        if (regs_ever_live[i] && !global_regs[i])
          restore_fpr (frame_pointer,
                       offset + 16*UNITS_PER_WORD + 8*(i-16), i);
    }

  /* Return register.  */

  return_reg = gen_rtx_REG (Pmode, RETURN_REGNUM);

  /* Restore call saved gprs.  */

  if (cfun->machine->first_restore_gpr != -1)
    {
      rtx insn, addr;
      int i;

      /* Check for global register and save them
         to stack location from where they get restored.  */

      for (i = cfun->machine->first_restore_gpr;
           i <= cfun->machine->last_restore_gpr;
           i++)
        {
          /* These registers are special and need to be
             restored in any case.  */
          if (i == STACK_POINTER_REGNUM
              || i == RETURN_REGNUM
              || i == BASE_REGISTER
              || (flag_pic && i == (int)PIC_OFFSET_TABLE_REGNUM))
            continue;

          if (global_regs[i])
            {
              addr = plus_constant (frame_pointer,
                     offset + i * UNITS_PER_WORD);
              addr = gen_rtx_MEM (Pmode, addr);
              set_mem_alias_set (addr, s390_sr_alias_set);
              emit_move_insn (addr, gen_rtx_REG (Pmode, i));
            }
        }

      if (! sibcall)
        {
          /* Fetch return address from stack before load multiple,
             this will do good for scheduling.  */

          if (cfun->machine->save_return_addr_p
              || (cfun->machine->first_restore_gpr < BASE_REGISTER
                  && cfun->machine->last_restore_gpr > RETURN_REGNUM))
            {
              int return_regnum = find_unused_clobbered_reg();
              if (!return_regnum)
                return_regnum = 4;
              return_reg = gen_rtx_REG (Pmode, return_regnum);

              addr = plus_constant (frame_pointer,
                                    offset + RETURN_REGNUM * UNITS_PER_WORD);
              addr = gen_rtx_MEM (Pmode, addr);
              set_mem_alias_set (addr, s390_sr_alias_set);
              emit_move_insn (return_reg, addr);
            }
        }

      insn = restore_gprs (frame_pointer, offset,
                           cfun->machine->first_restore_gpr,
                           cfun->machine->last_restore_gpr);
      emit_insn (insn);
    }

  if (! sibcall)
    {

      /* Return to caller.  */

      p = rtvec_alloc (2);

      RTVEC_ELT (p, 0) = gen_rtx_RETURN (VOIDmode);
      RTVEC_ELT (p, 1) = gen_rtx_USE (VOIDmode, return_reg);
      emit_jump_insn (gen_rtx_PARALLEL (VOIDmode, p));
    }
}


/* Return the size in bytes of a function argument of
   type TYPE and/or mode MODE.  At least one of TYPE or
   MODE must be specified.  */

static int
s390_function_arg_size (enum machine_mode mode, tree type)
{
  if (type)
    return int_size_in_bytes (type);

  /* No type info available for some library calls ...  */
  if (mode != BLKmode)
    return GET_MODE_SIZE (mode);

  /* If we have neither type nor mode, abort */
  abort ();
}

/* Return true if a function argument of type TYPE and mode MODE
   is to be passed in a floating-point register, if available.  */

static bool
s390_function_arg_float (enum machine_mode mode, tree type)
{
  int size = s390_function_arg_size (mode, type);
  if (size > 8)
    return false;

  /* Soft-float changes the ABI: no floating-point registers are used.  */
  if (TARGET_SOFT_FLOAT)
    return false;

  /* No type info available for some library calls ...  */
  if (!type)
    return mode == SFmode || mode == DFmode;

  /* The ABI says that record types with a single member are treated
     just like that member would be.  */
  while (TREE_CODE (type) == RECORD_TYPE)
    {
      tree field, single = NULL_TREE;

      for (field = TYPE_FIELDS (type); field; field = TREE_CHAIN (field))
        {
          if (TREE_CODE (field) != FIELD_DECL)
            continue;

          if (single == NULL_TREE)
            single = TREE_TYPE (field);
          else
            return false;
        }

      if (single == NULL_TREE)
        return false;
      else
        type = single;
    }

  return TREE_CODE (type) == REAL_TYPE;
}

/* Return true if a function argument of type TYPE and mode MODE
   is to be passed in an integer register, or a pair of integer
   registers, if available.  */

static bool
s390_function_arg_integer (enum machine_mode mode, tree type)
{
  int size = s390_function_arg_size (mode, type);
  if (size > 8)
    return false;

  /* No type info available for some library calls ...  */
  if (!type)
    return GET_MODE_CLASS (mode) == MODE_INT
           || (TARGET_SOFT_FLOAT &&  GET_MODE_CLASS (mode) == MODE_FLOAT);

  /* We accept small integral (and similar) types.  */
  if (INTEGRAL_TYPE_P (type)
      || POINTER_TYPE_P (type)
      || TREE_CODE (type) == OFFSET_TYPE
      || (TARGET_SOFT_FLOAT && TREE_CODE (type) == REAL_TYPE))
    return true;

  /* We also accept structs of size 1, 2, 4, 8 that are not
     passed in floating-point registers.  */
  if (AGGREGATE_TYPE_P (type)
      && exact_log2 (size) >= 0
      && !s390_function_arg_float (mode, type))
    return true;

  return false;
}

/* Return 1 if a function argument of type TYPE and mode MODE
   is to be passed by reference.  The ABI specifies that only
   structures of size 1, 2, 4, or 8 bytes are passed by value,
   all other structures (and complex numbers) are passed by
   reference.  */

int
s390_function_arg_pass_by_reference (enum machine_mode mode, tree type)
{
  int size = s390_function_arg_size (mode, type);
  if (size > 8)
    return true;

  if (type)
    {
      if (AGGREGATE_TYPE_P (type) && exact_log2 (size) < 0)
        return 1;

      if (TREE_CODE (type) == COMPLEX_TYPE
          || TREE_CODE (type) == VECTOR_TYPE)
        return 1;
    }

  return 0;
}

/* Update the data in CUM to advance over an argument of mode MODE and
   data type TYPE.  (TYPE is null for libcalls where that information
   may not be available.).  The boolean NAMED specifies whether the
   argument is a named argument (as opposed to an unnamed argument
   matching an ellipsis).  */

void
s390_function_arg_advance (CUMULATIVE_ARGS *cum, enum machine_mode mode,
                           tree type, int named ATTRIBUTE_UNUSED)
{
  if (s390_function_arg_pass_by_reference (mode, type))
    {
      cum->gprs += 1;
    }
  else if (s390_function_arg_float (mode, type))
    {
      cum->fprs += 1;
    }
  else if (s390_function_arg_integer (mode, type))
    {
      int size = s390_function_arg_size (mode, type);
      cum->gprs += ((size + UNITS_PER_WORD-1) / UNITS_PER_WORD);
    }
  else
    abort ();
}

/* Define where to put the arguments to a function.
   Value is zero to push the argument on the stack,
   or a hard register in which to store the argument.

   MODE is the argument's machine mode.
   TYPE is the data type of the argument (as a tree).
    This is null for libcalls where that information may
    not be available.
   CUM is a variable of type CUMULATIVE_ARGS which gives info about
    the preceding args and about the function being called.
   NAMED is nonzero if this argument is a named parameter
    (otherwise it is an extra parameter matching an ellipsis).

   On S/390, we use general purpose registers 2 through 6 to
   pass integer, pointer, and certain structure arguments, and
   floating point registers 0 and 2 (0, 2, 4, and 6 on 64-bit)
   to pass floating point arguments.  All remaining arguments
   are pushed to the stack.  */

rtx
s390_function_arg (CUMULATIVE_ARGS *cum, enum machine_mode mode, tree type,
                   int named ATTRIBUTE_UNUSED)
{
  if (s390_function_arg_pass_by_reference (mode, type))
      return 0;

  if (s390_function_arg_float (mode, type))
    {
      if (cum->fprs + 1 > (TARGET_64BIT? 4 : 2))
        return 0;
      else
        return gen_rtx_REG (mode, cum->fprs + 16);
    }
  else if (s390_function_arg_integer (mode, type))
    {
      int size = s390_function_arg_size (mode, type);
      int n_gprs = (size + UNITS_PER_WORD-1) / UNITS_PER_WORD;

      if (cum->gprs + n_gprs > 5)
        return 0;
      else
        return gen_rtx_REG (mode, cum->gprs + 2);
    }

  /* After the real arguments, expand_call calls us once again
     with a void_type_node type.  Whatever we return here is
     passed as operand 2 to the call expanders.

     We don't need this feature ...  */
  else if (type == void_type_node)
    return const0_rtx;

  abort ();
}

/* Return true if return values of type TYPE should be returned
   in a memory buffer whose address is passed by the caller as
   hidden first argument.  */

static bool
s390_return_in_memory (tree type, tree fundecl ATTRIBUTE_UNUSED)
{
  /* We accept small integral (and similar) types.  */
  if (INTEGRAL_TYPE_P (type)
      || POINTER_TYPE_P (type)
      || TREE_CODE (type) == OFFSET_TYPE
      || TREE_CODE (type) == REAL_TYPE)
    return int_size_in_bytes (type) > 8;

  /* Aggregates and similar constructs are always returned
     in memory.  */
  if (AGGREGATE_TYPE_P (type)
      || TREE_CODE (type) == COMPLEX_TYPE
      || TREE_CODE (type) == VECTOR_TYPE)
    return true;

  /* ??? We get called on all sorts of random stuff from
     aggregate_value_p.  We can't abort, but it's not clear
     what's safe to return.  Pretend it's a struct I guess.  */
  return true;
}

/* Define where to return a (scalar) value of type TYPE.
   If TYPE is null, define where to return a (scalar)
   value of mode MODE from a libcall.  */

rtx
s390_function_value (tree type, enum machine_mode mode)
{
  if (type)
    {
      int unsignedp = TYPE_UNSIGNED (type);
      mode = promote_mode (type, TYPE_MODE (type), &unsignedp, 1);
    }

  if (GET_MODE_CLASS (mode) != MODE_INT
      && GET_MODE_CLASS (mode) != MODE_FLOAT)
    abort ();
  if (GET_MODE_SIZE (mode) > 8)
    abort ();

  if (TARGET_HARD_FLOAT && GET_MODE_CLASS (mode) == MODE_FLOAT)
    return gen_rtx_REG (mode, 16);
  else
    return gen_rtx_REG (mode, 2);
}


/* Create and return the va_list datatype.

   On S/390, va_list is an array type equivalent to

      typedef struct __va_list_tag
        {
            long __gpr;
            long __fpr;
            void *__overflow_arg_area;
            void *__reg_save_area;
        } va_list[1];

   where __gpr and __fpr hold the number of general purpose
   or floating point arguments used up to now, respectively,
   __overflow_arg_area points to the stack location of the
   next argument passed on the stack, and __reg_save_area
   always points to the start of the register area in the
   call frame of the current function.  The function prologue
   saves all registers used for argument passing into this
   area if the function uses variable arguments.  */

static tree
s390_build_builtin_va_list (void)
{
  tree f_gpr, f_fpr, f_ovf, f_sav, record, type_decl;

  record = lang_hooks.types.make_type (RECORD_TYPE);

  type_decl =
    build_decl (TYPE_DECL, get_identifier ("__va_list_tag"), record);

  f_gpr = build_decl (FIELD_DECL, get_identifier ("__gpr"),
                      long_integer_type_node);
  f_fpr = build_decl (FIELD_DECL, get_identifier ("__fpr"),
                      long_integer_type_node);
  f_ovf = build_decl (FIELD_DECL, get_identifier ("__overflow_arg_area"),
                      ptr_type_node);
  f_sav = build_decl (FIELD_DECL, get_identifier ("__reg_save_area"),
                      ptr_type_node);

  DECL_FIELD_CONTEXT (f_gpr) = record;
  DECL_FIELD_CONTEXT (f_fpr) = record;
  DECL_FIELD_CONTEXT (f_ovf) = record;
  DECL_FIELD_CONTEXT (f_sav) = record;

  TREE_CHAIN (record) = type_decl;
  TYPE_NAME (record) = type_decl;
  TYPE_FIELDS (record) = f_gpr;
  TREE_CHAIN (f_gpr) = f_fpr;
  TREE_CHAIN (f_fpr) = f_ovf;
  TREE_CHAIN (f_ovf) = f_sav;

  layout_type (record);

  /* The correct type is an array type of one element.  */
  return build_array_type (record, build_index_type (size_zero_node));
}

/* Implement va_start by filling the va_list structure VALIST.
   STDARG_P is always true, and ignored.
   NEXTARG points to the first anonymous stack argument.

   The following global variables are used to initialize
   the va_list structure:

     current_function_args_info:
       holds number of gprs and fprs used for named arguments.
     current_function_arg_offset_rtx:
       holds the offset of the first anonymous stack argument
       (relative to the virtual arg pointer).  */

void
s390_va_start (tree valist, rtx nextarg ATTRIBUTE_UNUSED)
{
  HOST_WIDE_INT n_gpr, n_fpr;
  int off;
  tree f_gpr, f_fpr, f_ovf, f_sav;
  tree gpr, fpr, ovf, sav, t;

  f_gpr = TYPE_FIELDS (TREE_TYPE (va_list_type_node));
  f_fpr = TREE_CHAIN (f_gpr);
  f_ovf = TREE_CHAIN (f_fpr);
  f_sav = TREE_CHAIN (f_ovf);

  valist = build1 (INDIRECT_REF, TREE_TYPE (TREE_TYPE (valist)), valist);
  gpr = build (COMPONENT_REF, TREE_TYPE (f_gpr), valist, f_gpr, NULL_TREE);
  fpr = build (COMPONENT_REF, TREE_TYPE (f_fpr), valist, f_fpr, NULL_TREE);
  ovf = build (COMPONENT_REF, TREE_TYPE (f_ovf), valist, f_ovf, NULL_TREE);
  sav = build (COMPONENT_REF, TREE_TYPE (f_sav), valist, f_sav, NULL_TREE);

  /* Count number of gp and fp argument registers used.  */

  n_gpr = current_function_args_info.gprs;
  n_fpr = current_function_args_info.fprs;

  t = build (MODIFY_EXPR, TREE_TYPE (gpr), gpr, build_int_2 (n_gpr, 0));
  TREE_SIDE_EFFECTS (t) = 1;
  expand_expr (t, const0_rtx, VOIDmode, EXPAND_NORMAL);

  t = build (MODIFY_EXPR, TREE_TYPE (fpr), fpr, build_int_2 (n_fpr, 0));
  TREE_SIDE_EFFECTS (t) = 1;
  expand_expr (t, const0_rtx, VOIDmode, EXPAND_NORMAL);

  /* Find the overflow area.  */
  t = make_tree (TREE_TYPE (ovf), virtual_incoming_args_rtx);

  off = INTVAL (current_function_arg_offset_rtx);
  off = off < 0 ? 0 : off;
  if (TARGET_DEBUG_ARG)
    fprintf (stderr, "va_start: n_gpr = %d, n_fpr = %d off %d\n",
             (int)n_gpr, (int)n_fpr, off);

  t = build (PLUS_EXPR, TREE_TYPE (ovf), t, build_int_2 (off, 0));

  t = build (MODIFY_EXPR, TREE_TYPE (ovf), ovf, t);
  TREE_SIDE_EFFECTS (t) = 1;
  expand_expr (t, const0_rtx, VOIDmode, EXPAND_NORMAL);

  /* Find the register save area.  */
  t = make_tree (TREE_TYPE (sav), virtual_incoming_args_rtx);
  t = build (PLUS_EXPR, TREE_TYPE (sav), t,
             build_int_2 (-STACK_POINTER_OFFSET, -1));
  t = build (MODIFY_EXPR, TREE_TYPE (sav), sav, t);
  TREE_SIDE_EFFECTS (t) = 1;
  expand_expr (t, const0_rtx, VOIDmode, EXPAND_NORMAL);
}

/* Implement va_arg by updating the va_list structure
   VALIST as required to retrieve an argument of type
   TYPE, and returning that argument.

   Generates code equivalent to:

   if (integral value) {
     if (size  <= 4 && args.gpr < 5 ||
         size  > 4 && args.gpr < 4 )
       ret = args.reg_save_area[args.gpr+8]
     else
       ret = *args.overflow_arg_area++;
   } else if (float value) {
     if (args.fgpr < 2)
       ret = args.reg_save_area[args.fpr+64]
     else
       ret = *args.overflow_arg_area++;
   } else if (aggregate value) {
     if (args.gpr < 5)
       ret = *args.reg_save_area[args.gpr]
     else
       ret = **args.overflow_arg_area++;
   } */

tree
s390_gimplify_va_arg (tree valist, tree type, tree *pre_p, 
                      tree *post_p ATTRIBUTE_UNUSED)
{
  tree f_gpr, f_fpr, f_ovf, f_sav;
  tree gpr, fpr, ovf, sav, reg, t, u;
  int indirect_p, size, n_reg, sav_ofs, sav_scale, max_reg;
  tree lab_false, lab_over, addr;

  f_gpr = TYPE_FIELDS (TREE_TYPE (va_list_type_node));
  f_fpr = TREE_CHAIN (f_gpr);
  f_ovf = TREE_CHAIN (f_fpr);
  f_sav = TREE_CHAIN (f_ovf);

  valist = build1 (INDIRECT_REF, TREE_TYPE (TREE_TYPE (valist)), valist);
  gpr = build (COMPONENT_REF, TREE_TYPE (f_gpr), valist, f_gpr, NULL_TREE);
  fpr = build (COMPONENT_REF, TREE_TYPE (f_fpr), valist, f_fpr, NULL_TREE);
  ovf = build (COMPONENT_REF, TREE_TYPE (f_ovf), valist, f_ovf, NULL_TREE);
  sav = build (COMPONENT_REF, TREE_TYPE (f_sav), valist, f_sav, NULL_TREE);

  size = int_size_in_bytes (type);

  if (s390_function_arg_pass_by_reference (TYPE_MODE (type), type))
    {
      if (TARGET_DEBUG_ARG)
        {
          fprintf (stderr, "va_arg: aggregate type");
          debug_tree (type);
        }

      /* Aggregates are passed by reference.  */
      indirect_p = 1;
      reg = gpr;
      n_reg = 1;
      sav_ofs = 2 * UNITS_PER_WORD;
      sav_scale = UNITS_PER_WORD;
      size = UNITS_PER_WORD;
      max_reg = 4;
    }
  else if (s390_function_arg_float (TYPE_MODE (type), type))
    {
      if (TARGET_DEBUG_ARG)
        {
          fprintf (stderr, "va_arg: float type");
          debug_tree (type);
        }

      /* FP args go in FP registers, if present.  */
      indirect_p = 0;
      reg = fpr;
      n_reg = 1;
      sav_ofs = 16 * UNITS_PER_WORD;
      sav_scale = 8;
      /* TARGET_64BIT has up to 4 parameter in fprs */
      max_reg = TARGET_64BIT ? 3 : 1;
    }
  else
    {
      if (TARGET_DEBUG_ARG)
        {
          fprintf (stderr, "va_arg: other type");
          debug_tree (type);
        }

      /* Otherwise into GP registers.  */
      indirect_p = 0;
      reg = gpr;
      n_reg = (size + UNITS_PER_WORD - 1) / UNITS_PER_WORD;
      sav_ofs = 2 * UNITS_PER_WORD;

      if (size < UNITS_PER_WORD)
        sav_ofs += UNITS_PER_WORD - size;

      sav_scale = UNITS_PER_WORD;
      if (n_reg > 1)
        max_reg = 3;
      else
        max_reg = 4;
    }

  /* Pull the value out of the saved registers ...  */

  lab_false = create_artificial_label ();
  lab_over = create_artificial_label ();
  addr = create_tmp_var (ptr_type_node, "addr");

  t = build_int_2 (max_reg, 0);
  TREE_TYPE (t) = TREE_TYPE (reg);
  t = build2 (GT_EXPR, boolean_type_node, reg, t);
  u = build1 (GOTO_EXPR, void_type_node, lab_false);
  t = build3 (COND_EXPR, void_type_node, t, u, NULL_TREE);
  gimplify_and_add (t, pre_p);

  if (sav_ofs)
    t = build2 (PLUS_EXPR, ptr_type_node, sav, build_int_2 (sav_ofs, 0));
  else
    t = sav;

  u = build2 (MULT_EXPR, long_integer_type_node,
              reg, build_int_2 (sav_scale, 0));
  t = build2 (PLUS_EXPR, ptr_type_node, t, u);

  t = build2 (MODIFY_EXPR, void_type_node, addr, t);
  gimplify_and_add (t, pre_p);

  t = build1 (GOTO_EXPR, void_type_node, lab_over);
  gimplify_and_add (t, pre_p);

  t = build1 (LABEL_EXPR, void_type_node, lab_false);
  append_to_statement_list (t, pre_p);


  /* ... Otherwise out of the overflow area.  */

  t = ovf;
  if (size < UNITS_PER_WORD)
    t = build2 (PLUS_EXPR, TREE_TYPE (t), t, 
                build_int_2 (UNITS_PER_WORD - size, 0));

  gimplify_expr (&t, pre_p, NULL, is_gimple_val, fb_rvalue);

  u = build2 (MODIFY_EXPR, void_type_node, addr, t);
  gimplify_and_add (u, pre_p);

  t = build2 (PLUS_EXPR, TREE_TYPE (t), t, build_int_2 (size, 0));
  t = build2 (MODIFY_EXPR, TREE_TYPE (ovf), ovf, t);
  gimplify_and_add (t, pre_p);

  t = build1 (LABEL_EXPR, void_type_node, lab_over);
  append_to_statement_list (t, pre_p);


  /* Increment register save count.  */

  u = build2 (PREINCREMENT_EXPR, TREE_TYPE (reg), reg,
              build_int_2 (n_reg, 0));
  gimplify_and_add (u, pre_p);

  if (indirect_p)
    {
      t = build_pointer_type (build_pointer_type (type));
      addr = fold_convert (t, addr);
      addr = build_fold_indirect_ref (addr);
    }
  else
    {
      t = build_pointer_type (type);
      addr = fold_convert (t, addr);
    }

  return build_fold_indirect_ref (addr);
}


/* Builtins.  */

enum s390_builtin
{
  S390_BUILTIN_THREAD_POINTER,
  S390_BUILTIN_SET_THREAD_POINTER,

  S390_BUILTIN_max
};

static unsigned int const code_for_builtin_64[S390_BUILTIN_max] = {
  CODE_FOR_get_tp_64,
  CODE_FOR_set_tp_64
};

static unsigned int const code_for_builtin_31[S390_BUILTIN_max] = {
  CODE_FOR_get_tp_31,
  CODE_FOR_set_tp_31
};

static void
s390_init_builtins (void)
{
  tree ftype;

  ftype = build_function_type (ptr_type_node, void_list_node);
  builtin_function ("__builtin_thread_pointer", ftype,
                    S390_BUILTIN_THREAD_POINTER, BUILT_IN_MD,
                    NULL, NULL_TREE);

  ftype = build_function_type_list (void_type_node, ptr_type_node, NULL_TREE);
  builtin_function ("__builtin_set_thread_pointer", ftype,
                    S390_BUILTIN_SET_THREAD_POINTER, BUILT_IN_MD,
                    NULL, NULL_TREE);
}

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

static rtx
s390_expand_builtin (tree exp, rtx target, rtx subtarget ATTRIBUTE_UNUSED,
                     enum machine_mode mode ATTRIBUTE_UNUSED,
                     int ignore ATTRIBUTE_UNUSED)
{
#define MAX_ARGS 2

  unsigned int const *code_for_builtin =
    TARGET_64BIT ? code_for_builtin_64 : code_for_builtin_31;

  tree fndecl = TREE_OPERAND (TREE_OPERAND (exp, 0), 0);
  unsigned int fcode = DECL_FUNCTION_CODE (fndecl);
  tree arglist = TREE_OPERAND (exp, 1);
  enum insn_code icode;
  rtx op[MAX_ARGS], pat;
  int arity;
  bool nonvoid;

  if (fcode >= S390_BUILTIN_max)
    internal_error ("bad builtin fcode");
  icode = code_for_builtin[fcode];
  if (icode == 0)
    internal_error ("bad builtin fcode");

  nonvoid = TREE_TYPE (TREE_TYPE (fndecl)) != void_type_node;

  for (arglist = TREE_OPERAND (exp, 1), arity = 0;
       arglist;
       arglist = TREE_CHAIN (arglist), arity++)
    {
      const struct insn_operand_data *insn_op;

      tree arg = TREE_VALUE (arglist);
      if (arg == error_mark_node)
        return NULL_RTX;
      if (arity > MAX_ARGS)
        return NULL_RTX;

      insn_op = &insn_data[icode].operand[arity + nonvoid];

      op[arity] = expand_expr (arg, NULL_RTX, insn_op->mode, 0);

      if (!(*insn_op->predicate) (op[arity], insn_op->mode))
        op[arity] = copy_to_mode_reg (insn_op->mode, op[arity]);
    }

  if (nonvoid)
    {
      enum machine_mode tmode = insn_data[icode].operand[0].mode;
      if (!target
          || GET_MODE (target) != tmode
          || !(*insn_data[icode].operand[0].predicate) (target, tmode))
        target = gen_reg_rtx (tmode);
    }

  switch (arity)
    {
    case 0:
      pat = GEN_FCN (icode) (target);
      break;
    case 1:
      if (nonvoid)
        pat = GEN_FCN (icode) (target, op[0]);
      else
        pat = GEN_FCN (icode) (op[0]);
      break;
    case 2:
      pat = GEN_FCN (icode) (target, op[0], op[1]);
      break;
    default:
      abort ();
    }
  if (!pat)
    return NULL_RTX;
  emit_insn (pat);

  if (nonvoid)
    return target;
  else
    return const0_rtx;
}


/* Output assembly code for the trampoline template to
   stdio stream FILE.

   On S/390, we use gpr 1 internally in the trampoline code;
   gpr 0 is used to hold the static chain.  */

void
s390_trampoline_template (FILE *file)
{
  if (TARGET_64BIT)
    {
      fprintf (file, "larl\t%s,0f\n", reg_names[1]);
      fprintf (file, "lg\t%s,0(%s)\n", reg_names[0], reg_names[1]);
      fprintf (file, "lg\t%s,8(%s)\n", reg_names[1], reg_names[1]);
      fprintf (file, "br\t%s\n", reg_names[1]);
      fprintf (file, "0:\t.quad\t0\n");
      fprintf (file, ".quad\t0\n");
    }
  else
    {
      fprintf (file, "basr\t%s,0\n", reg_names[1]);
      fprintf (file, "l\t%s,10(%s)\n", reg_names[0], reg_names[1]);
      fprintf (file, "l\t%s,14(%s)\n", reg_names[1], reg_names[1]);
      fprintf (file, "br\t%s\n", reg_names[1]);
      fprintf (file, ".long\t0\n");
      fprintf (file, ".long\t0\n");
    }
}

/* Emit RTL insns to initialize the variable parts of a trampoline.
   FNADDR is an RTX for the address of the function's pure code.
   CXT is an RTX for the static chain value for the function.  */

void
s390_initialize_trampoline (rtx addr, rtx fnaddr, rtx cxt)
{
  emit_move_insn (gen_rtx_MEM (Pmode,
                   memory_address (Pmode,
                   plus_constant (addr, (TARGET_64BIT ? 20 : 12) ))), cxt);
  emit_move_insn (gen_rtx_MEM (Pmode,
                   memory_address (Pmode,
                   plus_constant (addr, (TARGET_64BIT ? 28 : 16) ))), fnaddr);
}

/* Return rtx for 64-bit constant formed from the 32-bit subwords
   LOW and HIGH, independent of the host word size.  */

rtx
s390_gen_rtx_const_DI (int high, int low)
{
#if HOST_BITS_PER_WIDE_INT >= 64
  HOST_WIDE_INT val;
  val = (HOST_WIDE_INT)high;
  val <<= 32;
  val |= (HOST_WIDE_INT)low;

  return GEN_INT (val);
#else
#if HOST_BITS_PER_WIDE_INT >= 32
  return immed_double_const ((HOST_WIDE_INT)low, (HOST_WIDE_INT)high, DImode);
#else
  abort ();
#endif
#endif
}

/* Output assembler code to FILE to increment profiler label # LABELNO
   for profiling a function entry.  */

void
s390_function_profiler (FILE *file, int labelno)
{
  rtx op[7];

  char label[128];
  ASM_GENERATE_INTERNAL_LABEL (label, "LP", labelno);

  fprintf (file, "# function profiler \n");

  op[0] = gen_rtx_REG (Pmode, RETURN_REGNUM);
  op[1] = gen_rtx_REG (Pmode, STACK_POINTER_REGNUM);
  op[1] = gen_rtx_MEM (Pmode, plus_constant (op[1], UNITS_PER_WORD));

  op[2] = gen_rtx_REG (Pmode, 1);
  op[3] = gen_rtx_SYMBOL_REF (Pmode, label);
  SYMBOL_REF_FLAGS (op[3]) = SYMBOL_FLAG_LOCAL;

  op[4] = gen_rtx_SYMBOL_REF (Pmode, "_mcount");
  if (flag_pic)
    {
      op[4] = gen_rtx_UNSPEC (Pmode, gen_rtvec (1, op[4]), UNSPEC_PLT);
      op[4] = gen_rtx_CONST (Pmode, op[4]);
    }

  if (TARGET_64BIT)
    {
      output_asm_insn ("stg\t%0,%1", op);
      output_asm_insn ("larl\t%2,%3", op);
      output_asm_insn ("brasl\t%0,%4", op);
      output_asm_insn ("lg\t%0,%1", op);
    }
  else if (!flag_pic)
    {
      op[6] = gen_label_rtx ();

      output_asm_insn ("st\t%0,%1", op);
      output_asm_insn ("bras\t%2,%l6", op);
      output_asm_insn (".long\t%4", op);
      output_asm_insn (".long\t%3", op);
      targetm.asm_out.internal_label (file, "L", CODE_LABEL_NUMBER (op[6]));
      output_asm_insn ("l\t%0,0(%2)", op);
      output_asm_insn ("l\t%2,4(%2)", op);
      output_asm_insn ("basr\t%0,%0", op);
      output_asm_insn ("l\t%0,%1", op);
    }
  else
    {
      op[5] = gen_label_rtx ();
      op[6] = gen_label_rtx ();

      output_asm_insn ("st\t%0,%1", op);
      output_asm_insn ("bras\t%2,%l6", op);
      targetm.asm_out.internal_label (file, "L", CODE_LABEL_NUMBER (op[5]));
      output_asm_insn (".long\t%4-%l5", op);
      output_asm_insn (".long\t%3-%l5", op);
      targetm.asm_out.internal_label (file, "L", CODE_LABEL_NUMBER (op[6]));
      output_asm_insn ("lr\t%0,%2", op);
      output_asm_insn ("a\t%0,0(%2)", op);
      output_asm_insn ("a\t%2,4(%2)", op);
      output_asm_insn ("basr\t%0,%0", op);
      output_asm_insn ("l\t%0,%1", op);
    }
}

/* Select section for constant in constant pool.  In 32-bit mode,
   constants go in the function section; in 64-bit mode in .rodata.  */

static void
s390_select_rtx_section (enum machine_mode mode ATTRIBUTE_UNUSED,
                         rtx x ATTRIBUTE_UNUSED,
                         unsigned HOST_WIDE_INT align ATTRIBUTE_UNUSED)
{
  if (TARGET_CPU_ZARCH)
    readonly_data_section ();
  else
    function_section (current_function_decl);
}

/* Encode symbol attributes (local vs. global, tls model) of a SYMBOL_REF
   into its SYMBOL_REF_FLAGS.  */

static void
s390_encode_section_info (tree decl, rtx rtl, int first)
{
  default_encode_section_info (decl, rtl, first);

  /* If a variable has a forced alignment to < 2 bytes, mark it with
     SYMBOL_FLAG_ALIGN1 to prevent it from being used as LARL operand.  */
  if (TREE_CODE (decl) == VAR_DECL
      && DECL_USER_ALIGN (decl) && DECL_ALIGN (decl) < 16)
    SYMBOL_REF_FLAGS (XEXP (rtl, 0)) |= SYMBOL_FLAG_ALIGN1;
}

/* Output thunk to FILE that implements a C++ virtual function call (with
   multiple inheritance) to FUNCTION.  The thunk adjusts the this pointer
   by DELTA, and unless VCALL_OFFSET is zero, applies an additional adjustment
   stored at VCALL_OFFSET in the vtable whose address is located at offset 0
   relative to the resulting this pointer.  */

static void
s390_output_mi_thunk (FILE *file, tree thunk ATTRIBUTE_UNUSED,
                      HOST_WIDE_INT delta, HOST_WIDE_INT vcall_offset,
                      tree function)
{
  rtx op[10];
  int nonlocal = 0;

  /* Operand 0 is the target function.  */
  op[0] = XEXP (DECL_RTL (function), 0);
  if (flag_pic && !SYMBOL_REF_LOCAL_P (op[0]))
    {
      nonlocal = 1;
      op[0] = gen_rtx_UNSPEC (Pmode, gen_rtvec (1, op[0]),
                              TARGET_64BIT ? UNSPEC_PLT : UNSPEC_GOT);
      op[0] = gen_rtx_CONST (Pmode, op[0]);
    }

  /* Operand 1 is the 'this' pointer.  */
  if (aggregate_value_p (TREE_TYPE (TREE_TYPE (function)), function))
    op[1] = gen_rtx_REG (Pmode, 3);
  else
    op[1] = gen_rtx_REG (Pmode, 2);

  /* Operand 2 is the delta.  */
  op[2] = GEN_INT (delta);

  /* Operand 3 is the vcall_offset.  */
  op[3] = GEN_INT (vcall_offset);

  /* Operand 4 is the temporary register.  */
  op[4] = gen_rtx_REG (Pmode, 1);

  /* Operands 5 to 8 can be used as labels.  */
  op[5] = NULL_RTX;
  op[6] = NULL_RTX;
  op[7] = NULL_RTX;
  op[8] = NULL_RTX;

  /* Operand 9 can be used for temporary register.  */
  op[9] = NULL_RTX;

  /* Generate code.  */
  if (TARGET_64BIT)
    {
      /* Setup literal pool pointer if required.  */
      if ((!DISP_IN_RANGE (delta)
           && !CONST_OK_FOR_CONSTRAINT_P (delta, 'K', "K"))
          || (!DISP_IN_RANGE (vcall_offset)
              && !CONST_OK_FOR_CONSTRAINT_P (vcall_offset, 'K', "K")))
        {
          op[5] = gen_label_rtx ();
          output_asm_insn ("larl\t%4,%5", op);
        }

      /* Add DELTA to this pointer.  */
      if (delta)
        {
          if (CONST_OK_FOR_CONSTRAINT_P (delta, 'J', "J"))
            output_asm_insn ("la\t%1,%2(%1)", op);
          else if (DISP_IN_RANGE (delta))
            output_asm_insn ("lay\t%1,%2(%1)", op);
          else if (CONST_OK_FOR_CONSTRAINT_P (delta, 'K', "K"))
            output_asm_insn ("aghi\t%1,%2", op);
          else
            {
              op[6] = gen_label_rtx ();
              output_asm_insn ("agf\t%1,%6-%5(%4)", op);
            }
        }

      /* Perform vcall adjustment.  */
      if (vcall_offset)
        {
          if (DISP_IN_RANGE (vcall_offset))
            {
              output_asm_insn ("lg\t%4,0(%1)", op);
              output_asm_insn ("ag\t%1,%3(%4)", op);
            }
          else if (CONST_OK_FOR_CONSTRAINT_P (vcall_offset, 'K', "K"))
            {
              output_asm_insn ("lghi\t%4,%3", op);
              output_asm_insn ("ag\t%4,0(%1)", op);
              output_asm_insn ("ag\t%1,0(%4)", op);
            }
          else
            {
              op[7] = gen_label_rtx ();
              output_asm_insn ("llgf\t%4,%7-%5(%4)", op);
              output_asm_insn ("ag\t%4,0(%1)", op);
              output_asm_insn ("ag\t%1,0(%4)", op);
            }
        }

      /* Jump to target.  */
      output_asm_insn ("jg\t%0", op);

      /* Output literal pool if required.  */
      if (op[5])
        {
          output_asm_insn (".align\t4", op);
          targetm.asm_out.internal_label (file, "L",
                                          CODE_LABEL_NUMBER (op[5]));
        }
      if (op[6])
        {
          targetm.asm_out.internal_label (file, "L",
                                          CODE_LABEL_NUMBER (op[6]));
          output_asm_insn (".long\t%2", op);
        }
      if (op[7])
        {
          targetm.asm_out.internal_label (file, "L",
                                          CODE_LABEL_NUMBER (op[7]));
          output_asm_insn (".long\t%3", op);
        }
    }
  else
    {
      /* Setup base pointer if required.  */
      if (!vcall_offset
          || (!DISP_IN_RANGE (delta)
              && !CONST_OK_FOR_CONSTRAINT_P (delta, 'K', "K"))
          || (!DISP_IN_RANGE (delta)
              && !CONST_OK_FOR_CONSTRAINT_P (vcall_offset, 'K', "K")))
        {
          op[5] = gen_label_rtx ();
          output_asm_insn ("basr\t%4,0", op);
          targetm.asm_out.internal_label (file, "L",
                                          CODE_LABEL_NUMBER (op[5]));
        }

      /* Add DELTA to this pointer.  */
      if (delta)
        {
          if (CONST_OK_FOR_CONSTRAINT_P (delta, 'J', "J"))
            output_asm_insn ("la\t%1,%2(%1)", op);
          else if (DISP_IN_RANGE (delta))
            output_asm_insn ("lay\t%1,%2(%1)", op);
          else if (CONST_OK_FOR_CONSTRAINT_P (delta, 'K', "K"))
            output_asm_insn ("ahi\t%1,%2", op);
          else
            {
              op[6] = gen_label_rtx ();
              output_asm_insn ("a\t%1,%6-%5(%4)", op);
            }
        }

      /* Perform vcall adjustment.  */
      if (vcall_offset)
        {
          if (CONST_OK_FOR_CONSTRAINT_P (vcall_offset, 'J', "J"))
            {
              output_asm_insn ("lg\t%4,0(%1)", op);
              output_asm_insn ("a\t%1,%3(%4)", op);
            }
          else if (DISP_IN_RANGE (vcall_offset))
            {
              output_asm_insn ("lg\t%4,0(%1)", op);
              output_asm_insn ("ay\t%1,%3(%4)", op);
            }
          else if (CONST_OK_FOR_CONSTRAINT_P (vcall_offset, 'K', "K"))
            {
              output_asm_insn ("lhi\t%4,%3", op);
              output_asm_insn ("a\t%4,0(%1)", op);
              output_asm_insn ("a\t%1,0(%4)", op);
            }
          else
            {
              op[7] = gen_label_rtx ();
              output_asm_insn ("l\t%4,%7-%5(%4)", op);
              output_asm_insn ("a\t%4,0(%1)", op);
              output_asm_insn ("a\t%1,0(%4)", op);
            }

          /* We had to clobber the base pointer register.
             Re-setup the base pointer (with a different base).  */
          op[5] = gen_label_rtx ();
          output_asm_insn ("basr\t%4,0", op);
          targetm.asm_out.internal_label (file, "L",
                                          CODE_LABEL_NUMBER (op[5]));
        }

      /* Jump to target.  */
      op[8] = gen_label_rtx ();

      if (!flag_pic)
        output_asm_insn ("l\t%4,%8-%5(%4)", op);
      else if (!nonlocal)
        output_asm_insn ("a\t%4,%8-%5(%4)", op);
      /* We cannot call through .plt, since .plt requires %r12 loaded.  */
      else if (flag_pic == 1)
        {
          output_asm_insn ("a\t%4,%8-%5(%4)", op);
          output_asm_insn ("l\t%4,%0(%4)", op);
        }
      else if (flag_pic == 2)
        {
          op[9] = gen_rtx_REG (Pmode, 0);
          output_asm_insn ("l\t%9,%8-4-%5(%4)", op);
          output_asm_insn ("a\t%4,%8-%5(%4)", op);
          output_asm_insn ("ar\t%4,%9", op);
          output_asm_insn ("l\t%4,0(%4)", op);
        }

      output_asm_insn ("br\t%4", op);

      /* Output literal pool.  */
      output_asm_insn (".align\t4", op);

      if (nonlocal && flag_pic == 2)
        output_asm_insn (".long\t%0", op);
      if (nonlocal)
        {
          op[0] = gen_rtx_SYMBOL_REF (Pmode, "_GLOBAL_OFFSET_TABLE_");
          SYMBOL_REF_FLAGS (op[0]) = SYMBOL_FLAG_LOCAL;
        }

      targetm.asm_out.internal_label (file, "L", CODE_LABEL_NUMBER (op[8]));
      if (!flag_pic)
        output_asm_insn (".long\t%0", op);
      else
        output_asm_insn (".long\t%0-%5", op);

      if (op[6])
        {
          targetm.asm_out.internal_label (file, "L",
                                          CODE_LABEL_NUMBER (op[6]));
          output_asm_insn (".long\t%2", op);
        }
      if (op[7])
        {
          targetm.asm_out.internal_label (file, "L",
                                          CODE_LABEL_NUMBER (op[7]));
          output_asm_insn (".long\t%3", op);
        }
    }
}

bool
s390_valid_pointer_mode (enum machine_mode mode)
{
  return (mode == SImode || (TARGET_64BIT && mode == DImode));
}

/* How to allocate a 'struct machine_function'.  */

static struct machine_function *
s390_init_machine_status (void)
{
  return ggc_alloc_cleared (sizeof (struct machine_function));
}

/* Checks whether the given ARGUMENT_LIST would use a caller
   saved register.  This is used to decide whether sibling call
   optimization could be performed on the respective function
   call.  */

static bool
s390_call_saved_register_used (tree argument_list)
{
  CUMULATIVE_ARGS cum;
  tree parameter;
  enum machine_mode mode;
  tree type;
  rtx parm_rtx;
  int reg;

  INIT_CUMULATIVE_ARGS (cum, NULL, NULL, 0, 0);

  while (argument_list)
    {
      parameter = TREE_VALUE (argument_list);
      argument_list = TREE_CHAIN (argument_list);

      if (!parameter)
        abort();

      /* For an undeclared variable passed as parameter we will get
         an ERROR_MARK node here.  */
      if (TREE_CODE (parameter) == ERROR_MARK)
        return true;

      if (! (type = TREE_TYPE (parameter)))
        abort();

      if (! (mode = TYPE_MODE (TREE_TYPE (parameter))))
        abort();

      if (s390_function_arg_pass_by_reference (mode, type))
        {
          mode = Pmode;
          type = build_pointer_type (type);
        }

       parm_rtx = s390_function_arg (&cum, mode, type, 0);

       s390_function_arg_advance (&cum, mode, type, 0);

       if (parm_rtx && REG_P (parm_rtx))
         {
           for (reg = 0;
                reg < HARD_REGNO_NREGS (REGNO (parm_rtx), GET_MODE (parm_rtx));
                reg++)
             if (! call_used_regs[reg + REGNO (parm_rtx)])
               return true;
         }
    }
  return false;
}

/* Return true if the given call expression can be
   turned into a sibling call.
   DECL holds the declaration of the function to be called whereas
   EXP is the call expression itself.  */

static bool
s390_function_ok_for_sibcall (tree decl, tree exp)
{
  /* The TPF epilogue uses register 1.  */
  if (TARGET_TPF_PROFILING)
    return false;

  /* The 31 bit PLT code uses register 12 (GOT pointer - caller saved)
     which would have to be restored before the sibcall.  */
  if (!TARGET_64BIT && flag_pic && decl && TREE_PUBLIC (decl))
    return false;

  /* Register 6 on s390 is available as an argument register but unfortunately
     "caller saved". This makes functions needing this register for arguments
     not suitable for sibcalls.  */
  if (TREE_OPERAND (exp, 1)
      && s390_call_saved_register_used (TREE_OPERAND (exp, 1)))
      return false;

  return true;
}

/* This function is used by the call expanders of the machine description.
   It emits the call insn itself together with the necessary operations
   to adjust the target address and returns the emitted insn.
   ADDR_LOCATION is the target address rtx
   TLS_CALL the location of the thread-local symbol
   RESULT_REG the register where the result of the call should be stored
   RETADDR_REG the register where the return address should be stored
               If this parameter is NULL_RTX the call is considered
               to be a sibling call.  */

rtx
s390_emit_call (rtx addr_location, rtx tls_call, rtx result_reg,
                rtx retaddr_reg)
{
  bool plt_call = false;
  rtx insn;
  rtx call;
  rtx clobber;
  rtvec vec;

  /* Direct function calls need special treatment.  */
  if (GET_CODE (addr_location) == SYMBOL_REF)
    {
      /* When calling a global routine in PIC mode, we must
         replace the symbol itself with the PLT stub.  */
      if (flag_pic && !SYMBOL_REF_LOCAL_P (addr_location))
        {
          addr_location = gen_rtx_UNSPEC (Pmode,
                                          gen_rtvec (1, addr_location),
                                          UNSPEC_PLT);
          addr_location = gen_rtx_CONST (Pmode, addr_location);
          plt_call = true;
        }

      /* Unless we can use the bras(l) insn, force the
         routine address into a register.  */
      if (!TARGET_SMALL_EXEC && !TARGET_CPU_ZARCH)
        {
          if (flag_pic)
            addr_location = legitimize_pic_address (addr_location, 0);
          else
            addr_location = force_reg (Pmode, addr_location);
        }
    }

  /* If it is already an indirect call or the code above moved the
     SYMBOL_REF to somewhere else make sure the address can be found in
     register 1.  */
  if (retaddr_reg == NULL_RTX
      && GET_CODE (addr_location) != SYMBOL_REF
      && !plt_call)
    {
      emit_move_insn (gen_rtx_REG (Pmode, SIBCALL_REGNUM), addr_location);
      addr_location = gen_rtx_REG (Pmode, SIBCALL_REGNUM);
    }

  addr_location = gen_rtx_MEM (QImode, addr_location);
  call = gen_rtx_CALL (VOIDmode, addr_location, const0_rtx);

  if (result_reg != NULL_RTX)
    call = gen_rtx_SET (VOIDmode, result_reg, call);

  if (retaddr_reg != NULL_RTX)
    {
      clobber = gen_rtx_CLOBBER (VOIDmode, retaddr_reg);

      if (tls_call != NULL_RTX)
        vec = gen_rtvec (3, call, clobber,
                         gen_rtx_USE (VOIDmode, tls_call));
      else
        vec = gen_rtvec (2, call, clobber);

      call = gen_rtx_PARALLEL (VOIDmode, vec);
    }

  insn = emit_call_insn (call);

  /* 31-bit PLT stubs and tls calls use the GOT register implicitly.  */
  if ((!TARGET_64BIT && plt_call) || tls_call != NULL_RTX)
    {
      /* s390_function_ok_for_sibcall should
         have denied sibcalls in this case.  */
      if (retaddr_reg == NULL_RTX)
        abort ();

      use_reg (&CALL_INSN_FUNCTION_USAGE (insn), pic_offset_table_rtx);
    }
  return insn;
}

/* Implement CONDITIONAL_REGISTER_USAGE.  */

void
s390_conditional_register_usage (void)
{
  int i;

  if (flag_pic)
    {
      fixed_regs[PIC_OFFSET_TABLE_REGNUM] = 1;
      call_used_regs[PIC_OFFSET_TABLE_REGNUM] = 1;
    }
  if (TARGET_CPU_ZARCH)
    {
      fixed_regs[RETURN_REGNUM] = 0;
      call_used_regs[RETURN_REGNUM] = 0;
    }
  if (TARGET_64BIT)
    {
      for (i = 24; i < 32; i++)
        call_used_regs[i] = call_really_used_regs[i] = 0;
    }
  else
    {
      for (i = 18; i < 20; i++)
        call_used_regs[i] = call_really_used_regs[i] = 0;
    }
}


#include "gt-s390.h"