PR target/52261

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

/* Subroutines for insn-output.c for ATMEL AVR micro controllers
   Copyright (C) 1998, 1999, 2000, 2001, 2002, 2004, 2005, 2006, 2007, 2008,
   2009, 2010, 2011 Free Software Foundation, Inc.
   Contributed by Denis Chertykov (chertykov@gmail.com)

   This file is part of GCC.

   GCC is free software; you can redistribute it and/or modify
   it under the terms of the GNU General Public License as published by
   the Free Software Foundation; either version 3, or (at your option)
   any later version.
   
   GCC is distributed in the hope that it will be useful,
   but WITHOUT ANY WARRANTY; without even the implied warranty of
   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
   GNU General Public License for more details.
   
   You should have received a copy of the GNU General Public License
   along with GCC; see the file COPYING3.  If not see
   <http://www.gnu.org/licenses/>.  */

#include "config.h"
#include "system.h"
#include "coretypes.h"
#include "tm.h"
#include "rtl.h"
#include "regs.h"
#include "hard-reg-set.h"
#include "insn-config.h"
#include "conditions.h"
#include "insn-attr.h"
#include "insn-codes.h"
#include "flags.h"
#include "reload.h"
#include "tree.h"
#include "output.h"
#include "expr.h"
#include "c-family/c-common.h"
#include "diagnostic-core.h"
#include "obstack.h"
#include "function.h"
#include "recog.h"
#include "optabs.h"
#include "ggc.h"
#include "langhooks.h"
#include "tm_p.h"
#include "target.h"
#include "target-def.h"
#include "params.h"
#include "df.h"

/* Maximal allowed offset for an address in the LD command */
#define MAX_LD_OFFSET(MODE) (64 - (signed)GET_MODE_SIZE (MODE))

/* Return true if STR starts with PREFIX and false, otherwise.  */
#define STR_PREFIX_P(STR,PREFIX) (0 == strncmp (STR, PREFIX, strlen (PREFIX)))

/* The 4 bits starting at SECTION_MACH_DEP are reserved to store the
   address space where data is to be located.
   As the only non-generic address spaces are all located in Flash,
   this can be used to test if data shall go into some .progmem* section.
   This must be the rightmost field of machine dependent section flags.  */
#define AVR_SECTION_PROGMEM (0xf * SECTION_MACH_DEP)

/* Similar 4-bit region for SYMBOL_REF_FLAGS.  */
#define AVR_SYMBOL_FLAG_PROGMEM (0xf * SYMBOL_FLAG_MACH_DEP)

/* Similar 4-bit region in SYMBOL_REF_FLAGS:
   Set address-space AS in SYMBOL_REF_FLAGS of SYM  */
#define AVR_SYMBOL_SET_ADDR_SPACE(SYM,AS)                       \
  do {                                                          \
    SYMBOL_REF_FLAGS (sym) &= ~AVR_SYMBOL_FLAG_PROGMEM;         \
    SYMBOL_REF_FLAGS (sym) |= (AS) * SYMBOL_FLAG_MACH_DEP;      \
  } while (0)

/* Read address-space from SYMBOL_REF_FLAGS of SYM  */
#define AVR_SYMBOL_GET_ADDR_SPACE(SYM)                          \
  ((SYMBOL_REF_FLAGS (sym) & AVR_SYMBOL_FLAG_PROGMEM)           \
   / SYMBOL_FLAG_MACH_DEP)

/* Known address spaces.  The order must be the same as in the respective
   enum from avr.h (or designated initialized must be used).  */
const avr_addrspace_t avr_addrspace[] =
{
    { ADDR_SPACE_RAM,  0, 2, ""     ,   0 },
    { ADDR_SPACE_FLASH,  1, 2, "__flash",   0 },
    { ADDR_SPACE_FLASH1, 1, 2, "__flash1",  1 },
    { ADDR_SPACE_FLASH2, 1, 2, "__flash2",  2 },
    { ADDR_SPACE_FLASH3, 1, 2, "__flash3",  3 },
    { ADDR_SPACE_FLASH4, 1, 2, "__flash4",  4 },
    { ADDR_SPACE_FLASH5, 1, 2, "__flash5",  5 },
    { ADDR_SPACE_MEMX, 1, 3, "__memx",  0 },
    { 0              , 0, 0, NULL,      0 }
};

/* Map 64-k Flash segment to section prefix.  */
static const char* const progmem_section_prefix[6] =
  {
    ".progmem.data",
    ".progmem1.data",
    ".progmem2.data",
    ".progmem3.data",
    ".progmem4.data",
    ".progmem5.data"
  };

/* Holding RAM addresses of some SFRs used by the compiler and that
   are unique over all devices in an architecture like 'avr4'.  */
  
typedef struct
{
  /* SREG: The pocessor status */
  int sreg;

  /* RAMPX, RAMPY, RAMPD and CCP of XMEGA */
  int ccp;
  int rampd;
  int rampx;
  int rampy;

  /* RAMPZ: The high byte of 24-bit address used with ELPM */ 
  int rampz;

  /* SP: The stack pointer and its low and high byte */
  int sp_l;
  int sp_h;
} avr_addr_t;

static avr_addr_t avr_addr;


/* Prototypes for local helper functions.  */

static const char* out_movqi_r_mr (rtx, rtx[], int*);
static const char* out_movhi_r_mr (rtx, rtx[], int*);
static const char* out_movsi_r_mr (rtx, rtx[], int*);
static const char* out_movqi_mr_r (rtx, rtx[], int*);
static const char* out_movhi_mr_r (rtx, rtx[], int*);
static const char* out_movsi_mr_r (rtx, rtx[], int*);

static int avr_naked_function_p (tree);
static int interrupt_function_p (tree);
static int signal_function_p (tree);
static int avr_OS_task_function_p (tree);
static int avr_OS_main_function_p (tree);
static int avr_regs_to_save (HARD_REG_SET *);
static int get_sequence_length (rtx insns);
static int sequent_regs_live (void);
static const char *ptrreg_to_str (int);
static const char *cond_string (enum rtx_code);
static int avr_num_arg_regs (enum machine_mode, const_tree);
static int avr_operand_rtx_cost (rtx, enum machine_mode, enum rtx_code,
                                 int, bool);
static void output_reload_in_const (rtx*, rtx, int*, bool);
static struct machine_function * avr_init_machine_status (void);


/* Prototypes for hook implementors if needed before their implementation.  */

static bool avr_rtx_costs (rtx, int, int, int, int *, bool);


/* Allocate registers from r25 to r8 for parameters for function calls.  */
#define FIRST_CUM_REG 26

/* Implicit target register of LPM instruction (R0) */
extern GTY(()) rtx lpm_reg_rtx;
rtx lpm_reg_rtx;

/* (Implicit) address register of LPM instruction (R31:R30 = Z) */
extern GTY(()) rtx lpm_addr_reg_rtx;
rtx lpm_addr_reg_rtx;

/* Temporary register RTX (reg:QI TMP_REGNO) */
extern GTY(()) rtx tmp_reg_rtx;
rtx tmp_reg_rtx;

/* Zeroed register RTX (reg:QI ZERO_REGNO) */
extern GTY(()) rtx zero_reg_rtx;
rtx zero_reg_rtx;

/* RTXs for all general purpose registers as QImode */
extern GTY(()) rtx all_regs_rtx[32];
rtx all_regs_rtx[32];

/* SREG, the processor status */
extern GTY(()) rtx sreg_rtx;
rtx sreg_rtx;

/* RAMP* special function registers */
extern GTY(()) rtx rampd_rtx;
extern GTY(()) rtx rampx_rtx;
extern GTY(()) rtx rampy_rtx;
extern GTY(()) rtx rampz_rtx;
rtx rampd_rtx;
rtx rampx_rtx;
rtx rampy_rtx;
rtx rampz_rtx;

/* RTX containing the strings "" and "e", respectively */
static GTY(()) rtx xstring_empty;
static GTY(()) rtx xstring_e;

/* Preprocessor macros to define depending on MCU type.  */
const char *avr_extra_arch_macro;

/* Current architecture.  */
const struct base_arch_s *avr_current_arch;

/* Current device.  */
const struct mcu_type_s *avr_current_device;

/* Section to put switch tables in.  */
static GTY(()) section *progmem_swtable_section;

/* Unnamed sections associated to __attribute__((progmem)) aka. PROGMEM
   or to address space __flash*.  */
static GTY(()) section *progmem_section[6];

/* Condition for insns/expanders from avr-dimode.md.  */
bool avr_have_dimode = true;

/* To track if code will use .bss and/or .data.  */
bool avr_need_clear_bss_p = false;
bool avr_need_copy_data_p = false;

\f
/* Initialize the GCC target structure.  */
#undef TARGET_ASM_ALIGNED_HI_OP
#define TARGET_ASM_ALIGNED_HI_OP "\t.word\t"
#undef TARGET_ASM_ALIGNED_SI_OP
#define TARGET_ASM_ALIGNED_SI_OP "\t.long\t"
#undef TARGET_ASM_UNALIGNED_HI_OP
#define TARGET_ASM_UNALIGNED_HI_OP "\t.word\t"
#undef TARGET_ASM_UNALIGNED_SI_OP
#define TARGET_ASM_UNALIGNED_SI_OP "\t.long\t"
#undef TARGET_ASM_INTEGER
#define TARGET_ASM_INTEGER avr_assemble_integer
#undef TARGET_ASM_FILE_START
#define TARGET_ASM_FILE_START avr_file_start
#undef TARGET_ASM_FILE_END
#define TARGET_ASM_FILE_END avr_file_end

#undef TARGET_ASM_FUNCTION_END_PROLOGUE
#define TARGET_ASM_FUNCTION_END_PROLOGUE avr_asm_function_end_prologue
#undef TARGET_ASM_FUNCTION_BEGIN_EPILOGUE
#define TARGET_ASM_FUNCTION_BEGIN_EPILOGUE avr_asm_function_begin_epilogue

#undef TARGET_FUNCTION_VALUE
#define TARGET_FUNCTION_VALUE avr_function_value
#undef TARGET_LIBCALL_VALUE
#define TARGET_LIBCALL_VALUE avr_libcall_value
#undef TARGET_FUNCTION_VALUE_REGNO_P
#define TARGET_FUNCTION_VALUE_REGNO_P avr_function_value_regno_p

#undef TARGET_ATTRIBUTE_TABLE
#define TARGET_ATTRIBUTE_TABLE avr_attribute_table
#undef TARGET_INSERT_ATTRIBUTES
#define TARGET_INSERT_ATTRIBUTES avr_insert_attributes
#undef TARGET_SECTION_TYPE_FLAGS
#define TARGET_SECTION_TYPE_FLAGS avr_section_type_flags

#undef TARGET_ASM_NAMED_SECTION
#define TARGET_ASM_NAMED_SECTION avr_asm_named_section
#undef TARGET_ASM_INIT_SECTIONS
#define TARGET_ASM_INIT_SECTIONS avr_asm_init_sections
#undef TARGET_ENCODE_SECTION_INFO
#define TARGET_ENCODE_SECTION_INFO avr_encode_section_info
#undef TARGET_ASM_SELECT_SECTION
#define TARGET_ASM_SELECT_SECTION avr_asm_select_section

#undef TARGET_REGISTER_MOVE_COST
#define TARGET_REGISTER_MOVE_COST avr_register_move_cost
#undef TARGET_MEMORY_MOVE_COST
#define TARGET_MEMORY_MOVE_COST avr_memory_move_cost
#undef TARGET_RTX_COSTS
#define TARGET_RTX_COSTS avr_rtx_costs
#undef TARGET_ADDRESS_COST
#define TARGET_ADDRESS_COST avr_address_cost
#undef TARGET_MACHINE_DEPENDENT_REORG
#define TARGET_MACHINE_DEPENDENT_REORG avr_reorg
#undef TARGET_FUNCTION_ARG
#define TARGET_FUNCTION_ARG avr_function_arg
#undef TARGET_FUNCTION_ARG_ADVANCE
#define TARGET_FUNCTION_ARG_ADVANCE avr_function_arg_advance

#undef TARGET_RETURN_IN_MEMORY
#define TARGET_RETURN_IN_MEMORY avr_return_in_memory

#undef TARGET_STRICT_ARGUMENT_NAMING
#define TARGET_STRICT_ARGUMENT_NAMING hook_bool_CUMULATIVE_ARGS_true

#undef TARGET_BUILTIN_SETJMP_FRAME_VALUE
#define TARGET_BUILTIN_SETJMP_FRAME_VALUE avr_builtin_setjmp_frame_value

#undef TARGET_HARD_REGNO_SCRATCH_OK
#define TARGET_HARD_REGNO_SCRATCH_OK avr_hard_regno_scratch_ok
#undef TARGET_CASE_VALUES_THRESHOLD
#define TARGET_CASE_VALUES_THRESHOLD avr_case_values_threshold

#undef TARGET_FRAME_POINTER_REQUIRED
#define TARGET_FRAME_POINTER_REQUIRED avr_frame_pointer_required_p
#undef TARGET_CAN_ELIMINATE
#define TARGET_CAN_ELIMINATE avr_can_eliminate

#undef TARGET_CLASS_LIKELY_SPILLED_P
#define TARGET_CLASS_LIKELY_SPILLED_P avr_class_likely_spilled_p

#undef TARGET_OPTION_OVERRIDE
#define TARGET_OPTION_OVERRIDE avr_option_override

#undef TARGET_CANNOT_MODIFY_JUMPS_P
#define TARGET_CANNOT_MODIFY_JUMPS_P avr_cannot_modify_jumps_p

#undef TARGET_FUNCTION_OK_FOR_SIBCALL
#define TARGET_FUNCTION_OK_FOR_SIBCALL avr_function_ok_for_sibcall

#undef TARGET_INIT_BUILTINS
#define TARGET_INIT_BUILTINS avr_init_builtins

#undef TARGET_EXPAND_BUILTIN
#define TARGET_EXPAND_BUILTIN avr_expand_builtin

#undef  TARGET_FOLD_BUILTIN
#define TARGET_FOLD_BUILTIN avr_fold_builtin

#undef TARGET_ASM_FUNCTION_RODATA_SECTION
#define TARGET_ASM_FUNCTION_RODATA_SECTION avr_asm_function_rodata_section

#undef  TARGET_SCALAR_MODE_SUPPORTED_P
#define TARGET_SCALAR_MODE_SUPPORTED_P avr_scalar_mode_supported_p

#undef  TARGET_ADDR_SPACE_SUBSET_P
#define TARGET_ADDR_SPACE_SUBSET_P avr_addr_space_subset_p

#undef  TARGET_ADDR_SPACE_CONVERT
#define TARGET_ADDR_SPACE_CONVERT avr_addr_space_convert

#undef  TARGET_ADDR_SPACE_ADDRESS_MODE
#define TARGET_ADDR_SPACE_ADDRESS_MODE avr_addr_space_address_mode

#undef  TARGET_ADDR_SPACE_POINTER_MODE
#define TARGET_ADDR_SPACE_POINTER_MODE avr_addr_space_pointer_mode

#undef  TARGET_ADDR_SPACE_LEGITIMATE_ADDRESS_P
#define TARGET_ADDR_SPACE_LEGITIMATE_ADDRESS_P avr_addr_space_legitimate_address_p

#undef TARGET_ADDR_SPACE_LEGITIMIZE_ADDRESS
#define TARGET_ADDR_SPACE_LEGITIMIZE_ADDRESS avr_addr_space_legitimize_address

#undef  TARGET_PRINT_OPERAND
#define TARGET_PRINT_OPERAND avr_print_operand
#undef  TARGET_PRINT_OPERAND_ADDRESS
#define TARGET_PRINT_OPERAND_ADDRESS avr_print_operand_address
#undef  TARGET_PRINT_OPERAND_PUNCT_VALID_P
#define TARGET_PRINT_OPERAND_PUNCT_VALID_P avr_print_operand_punct_valid_p

\f

/* Custom function to count number of set bits.  */

static inline int
avr_popcount (unsigned int val)
{
  int pop = 0;

  while (val)
    {
      val &= val-1;
      pop++;
    }

  return pop;
}


/* Constraint helper function.  XVAL is a CONST_INT or a CONST_DOUBLE.
   Return true if the least significant N_BYTES bytes of XVAL all have a
   popcount in POP_MASK and false, otherwise.  POP_MASK represents a subset
   of integers which contains an integer N iff bit N of POP_MASK is set.  */
   
bool
avr_popcount_each_byte (rtx xval, int n_bytes, int pop_mask)
{
  int i;

  enum machine_mode mode = GET_MODE (xval);

  if (VOIDmode == mode)
    mode = SImode;

  for (i = 0; i < n_bytes; i++)
    {
      rtx xval8 = simplify_gen_subreg (QImode, xval, mode, i);
      unsigned int val8 = UINTVAL (xval8) & GET_MODE_MASK (QImode);

      if (0 == (pop_mask & (1 << avr_popcount (val8))))
        return false;
    }

  return true;
}

static void
avr_option_override (void)
{
  flag_delete_null_pointer_checks = 0;

  /* caller-save.c looks for call-clobbered hard registers that are assigned
     to pseudos that cross calls and tries so save-restore them around calls
     in order to reduce the number of stack slots needed.

     This might leads to situations where reload is no more able to cope
     with the challenge of AVR's very few address registers and fails to
     perform the requested spills.  */
  
  if (avr_strict_X)
    flag_caller_saves = 0;

  /* Unwind tables currently require a frame pointer for correctness,
     see toplev.c:process_options().  */

  if ((flag_unwind_tables
       || flag_non_call_exceptions
       || flag_asynchronous_unwind_tables)
      && !ACCUMULATE_OUTGOING_ARGS)
    {
      flag_omit_frame_pointer = 0;
    }

  avr_current_device = &avr_mcu_types[avr_mcu_index];
  avr_current_arch = &avr_arch_types[avr_current_device->arch];
  avr_extra_arch_macro = avr_current_device->macro;
  
  /* RAM addresses of some SFRs common to all Devices in respective Arch. */

  /* SREG: Status Register containing flags like I (global IRQ) */
  avr_addr.sreg = 0x3F + avr_current_arch->sfr_offset;

  /* RAMPZ: Address' high part when loading via ELPM */
  avr_addr.rampz = 0x3B + avr_current_arch->sfr_offset;

  avr_addr.rampy = 0x3A + avr_current_arch->sfr_offset;
  avr_addr.rampx = 0x39 + avr_current_arch->sfr_offset;
  avr_addr.rampd = 0x38 + avr_current_arch->sfr_offset;
  avr_addr.ccp = 0x34 + avr_current_arch->sfr_offset;

  /* SP: Stack Pointer (SP_H:SP_L) */
  avr_addr.sp_l = 0x3D + avr_current_arch->sfr_offset;
  avr_addr.sp_h = avr_addr.sp_l + 1;

  init_machine_status = avr_init_machine_status;

  avr_log_set_avr_log();
}

/* Function to set up the backend function structure.  */

static struct machine_function *
avr_init_machine_status (void)
{
  return ggc_alloc_cleared_machine_function ();
}


/* Implement `INIT_EXPANDERS'.  */
/* The function works like a singleton.  */

void
avr_init_expanders (void)
{
  int regno;

  for (regno = 0; regno < 32; regno ++)
    all_regs_rtx[regno] = gen_rtx_REG (QImode, regno);

  lpm_reg_rtx  = all_regs_rtx[LPM_REGNO];
  tmp_reg_rtx  = all_regs_rtx[TMP_REGNO];
  zero_reg_rtx = all_regs_rtx[ZERO_REGNO];

  lpm_addr_reg_rtx = gen_rtx_REG (HImode, REG_Z);

  sreg_rtx = gen_rtx_MEM (QImode, GEN_INT (avr_addr.sreg));
  rampd_rtx = gen_rtx_MEM (QImode, GEN_INT (avr_addr.rampd));
  rampx_rtx = gen_rtx_MEM (QImode, GEN_INT (avr_addr.rampx));
  rampy_rtx = gen_rtx_MEM (QImode, GEN_INT (avr_addr.rampy));
  rampz_rtx = gen_rtx_MEM (QImode, GEN_INT (avr_addr.rampz));

  xstring_empty = gen_rtx_CONST_STRING (VOIDmode, "");
  xstring_e = gen_rtx_CONST_STRING (VOIDmode, "e");
}


/* Return register class for register R.  */

enum reg_class
avr_regno_reg_class (int r)
{
  static const enum reg_class reg_class_tab[] =
    {
      R0_REG,
      /* r1 - r15 */
      NO_LD_REGS, NO_LD_REGS, NO_LD_REGS,
      NO_LD_REGS, NO_LD_REGS, NO_LD_REGS, NO_LD_REGS,
      NO_LD_REGS, NO_LD_REGS, NO_LD_REGS, NO_LD_REGS,
      NO_LD_REGS, NO_LD_REGS, NO_LD_REGS, NO_LD_REGS,
      /* r16 - r23 */
      SIMPLE_LD_REGS, SIMPLE_LD_REGS, SIMPLE_LD_REGS, SIMPLE_LD_REGS,
      SIMPLE_LD_REGS, SIMPLE_LD_REGS, SIMPLE_LD_REGS, SIMPLE_LD_REGS,
      /* r24, r25 */
      ADDW_REGS, ADDW_REGS,
      /* X: r26, 27 */
      POINTER_X_REGS, POINTER_X_REGS,
      /* Y: r28, r29 */
      POINTER_Y_REGS, POINTER_Y_REGS,
      /* Z: r30, r31 */
      POINTER_Z_REGS, POINTER_Z_REGS,
      /* SP: SPL, SPH */
      STACK_REG, STACK_REG
    };

  if (r <= 33)
    return reg_class_tab[r];
  
  return ALL_REGS;
}


static bool
avr_scalar_mode_supported_p (enum machine_mode mode)
{
  if (PSImode == mode)
    return true;

  return default_scalar_mode_supported_p (mode);
}


/* Return TRUE if DECL is a VAR_DECL located in Flash and FALSE, otherwise.  */

static bool
avr_decl_flash_p (tree decl)
{
  if (TREE_CODE (decl) != VAR_DECL
      || TREE_TYPE (decl) == error_mark_node)
    {
      return false;
    }

  return !ADDR_SPACE_GENERIC_P (TYPE_ADDR_SPACE (TREE_TYPE (decl)));
}


/* Return TRUE if DECL is a VAR_DECL located in the 24-bit Flash
   address space and FALSE, otherwise.  */
 
static bool
avr_decl_memx_p (tree decl)
{
  if (TREE_CODE (decl) != VAR_DECL
      || TREE_TYPE (decl) == error_mark_node)
    {
      return false;
    }

  return (ADDR_SPACE_MEMX == TYPE_ADDR_SPACE (TREE_TYPE (decl)));
}


/* Return TRUE if X is a MEM rtx located in Flash and FALSE, otherwise.  */

bool
avr_mem_flash_p (rtx x)
{
  return (MEM_P (x)
          && !ADDR_SPACE_GENERIC_P (MEM_ADDR_SPACE (x)));
}


/* Return TRUE if X is a MEM rtx located in the 24-bit Flash
   address space and FALSE, otherwise.  */

bool
avr_mem_memx_p (rtx x)
{
  return (MEM_P (x)
          && ADDR_SPACE_MEMX == MEM_ADDR_SPACE (x));
}


/* A helper for the subsequent function attribute used to dig for
   attribute 'name' in a FUNCTION_DECL or FUNCTION_TYPE */

static inline int
avr_lookup_function_attribute1 (const_tree func, const char *name)
{
  if (FUNCTION_DECL == TREE_CODE (func))
    {
      if (NULL_TREE != lookup_attribute (name, DECL_ATTRIBUTES (func)))
        {
          return true;
        }
      
      func = TREE_TYPE (func);
    }

  gcc_assert (TREE_CODE (func) == FUNCTION_TYPE
              || TREE_CODE (func) == METHOD_TYPE);
  
  return NULL_TREE != lookup_attribute (name, TYPE_ATTRIBUTES (func));
}

/* Return nonzero if FUNC is a naked function.  */

static int
avr_naked_function_p (tree func)
{
  return avr_lookup_function_attribute1 (func, "naked");
}

/* Return nonzero if FUNC is an interrupt function as specified
   by the "interrupt" attribute.  */

static int
interrupt_function_p (tree func)
{
  return avr_lookup_function_attribute1 (func, "interrupt");
}

/* Return nonzero if FUNC is a signal function as specified
   by the "signal" attribute.  */

static int
signal_function_p (tree func)
{
  return avr_lookup_function_attribute1 (func, "signal");
}

/* Return nonzero if FUNC is an OS_task function.  */

static int
avr_OS_task_function_p (tree func)
{
  return avr_lookup_function_attribute1 (func, "OS_task");
}

/* Return nonzero if FUNC is an OS_main function.  */

static int
avr_OS_main_function_p (tree func)
{
  return avr_lookup_function_attribute1 (func, "OS_main");
}


/* Implement `ACCUMULATE_OUTGOING_ARGS'.  */

int
avr_accumulate_outgoing_args (void)
{
  if (!cfun)
    return TARGET_ACCUMULATE_OUTGOING_ARGS;

  /* FIXME: For setjmp and in avr_builtin_setjmp_frame_value we don't know
        what offset is correct.  In some cases it is relative to
        virtual_outgoing_args_rtx and in others it is relative to
        virtual_stack_vars_rtx.  For example code see
            gcc.c-torture/execute/built-in-setjmp.c
            gcc.c-torture/execute/builtins/sprintf-chk.c   */
  
  return (TARGET_ACCUMULATE_OUTGOING_ARGS
          && !(cfun->calls_setjmp
               || cfun->has_nonlocal_label));
}


/* Report contribution of accumulated outgoing arguments to stack size.  */

static inline int
avr_outgoing_args_size (void)
{
  return ACCUMULATE_OUTGOING_ARGS ? crtl->outgoing_args_size : 0;
}


/* Implement `STARTING_FRAME_OFFSET'.  */
/* This is the offset from the frame pointer register to the first stack slot
   that contains a variable living in the frame.  */

int
avr_starting_frame_offset (void)
{
  return 1 + avr_outgoing_args_size ();
}


/* Return the number of hard registers to push/pop in the prologue/epilogue
   of the current function, and optionally store these registers in SET.  */

static int
avr_regs_to_save (HARD_REG_SET *set)
{
  int reg, count;
  int int_or_sig_p = (interrupt_function_p (current_function_decl)
                      || signal_function_p (current_function_decl));

  if (set)
    CLEAR_HARD_REG_SET (*set);
  count = 0;

  /* No need to save any registers if the function never returns or 
     has the "OS_task" or "OS_main" attribute.  */
  if (TREE_THIS_VOLATILE (current_function_decl)
      || cfun->machine->is_OS_task
      || cfun->machine->is_OS_main)
    return 0;

  for (reg = 0; reg < 32; reg++)
    {
      /* Do not push/pop __tmp_reg__, __zero_reg__, as well as
         any global register variables.  */
      if (fixed_regs[reg])
        continue;

      if ((int_or_sig_p && !current_function_is_leaf && call_used_regs[reg])
          || (df_regs_ever_live_p (reg)
              && (int_or_sig_p || !call_used_regs[reg])
              /* Don't record frame pointer registers here.  They are treated
                 indivitually in prologue.  */
              && !(frame_pointer_needed
                   && (reg == REG_Y || reg == (REG_Y+1)))))
        {
          if (set)
            SET_HARD_REG_BIT (*set, reg);
          count++;
        }
    }
  return count;
}

/* Return true if register FROM can be eliminated via register TO.  */

static bool
avr_can_eliminate (const int from, const int to)
{
  return ((from == ARG_POINTER_REGNUM && to == FRAME_POINTER_REGNUM)
          || (frame_pointer_needed && to == FRAME_POINTER_REGNUM)
          || ((from == FRAME_POINTER_REGNUM 
               || from == FRAME_POINTER_REGNUM + 1)
              && !frame_pointer_needed));
}

/* Compute offset between arg_pointer and frame_pointer.  */

int
avr_initial_elimination_offset (int from, int to)
{
  if (from == FRAME_POINTER_REGNUM && to == STACK_POINTER_REGNUM)
    return 0;
  else
    {
      int offset = frame_pointer_needed ? 2 : 0;
      int avr_pc_size = AVR_HAVE_EIJMP_EICALL ? 3 : 2;
      
      offset += avr_regs_to_save (NULL);
      return (get_frame_size () + avr_outgoing_args_size()
              + avr_pc_size + 1 + offset);
    }
}

/* Actual start of frame is virtual_stack_vars_rtx this is offset from 
   frame pointer by +STARTING_FRAME_OFFSET.
   Using saved frame = virtual_stack_vars_rtx - STARTING_FRAME_OFFSET
   avoids creating add/sub of offset in nonlocal goto and setjmp.  */

static rtx
avr_builtin_setjmp_frame_value (void)
{
  return gen_rtx_MINUS (Pmode, virtual_stack_vars_rtx, 
                        gen_int_mode (STARTING_FRAME_OFFSET, Pmode));
}

/* Return contents of MEM at frame pointer + stack size + 1 (+2 if 3 byte PC).
   This is return address of function.  */
rtx 
avr_return_addr_rtx (int count, rtx tem)
{
  rtx r;
    
  /* Can only return this function's return address. Others not supported.  */
  if (count)
     return NULL;

  if (AVR_3_BYTE_PC)
    {
      r = gen_rtx_SYMBOL_REF (Pmode, ".L__stack_usage+2");
      warning (0, "'builtin_return_address' contains only 2 bytes of address");
    }
  else
    r = gen_rtx_SYMBOL_REF (Pmode, ".L__stack_usage+1");

  r = gen_rtx_PLUS (Pmode, tem, r);
  r = gen_frame_mem (Pmode, memory_address (Pmode, r));
  r = gen_rtx_ROTATE (HImode, r, GEN_INT (8));
  return  r;
}

/* Return 1 if the function epilogue is just a single "ret".  */

int
avr_simple_epilogue (void)
{
  return (! frame_pointer_needed
          && get_frame_size () == 0
          && avr_outgoing_args_size() == 0
          && avr_regs_to_save (NULL) == 0
          && ! interrupt_function_p (current_function_decl)
          && ! signal_function_p (current_function_decl)
          && ! avr_naked_function_p (current_function_decl)
          && ! TREE_THIS_VOLATILE (current_function_decl));
}

/* This function checks sequence of live registers.  */

static int
sequent_regs_live (void)
{
  int reg;
  int live_seq=0;
  int cur_seq=0;

  for (reg = 0; reg < 18; ++reg)
    {
      if (fixed_regs[reg])
        {
          /* Don't recognize sequences that contain global register
             variables.  */
      
          if (live_seq != 0)
            return 0;
          else
            continue;
        }
      
      if (!call_used_regs[reg])
        {
          if (df_regs_ever_live_p (reg))
            {
              ++live_seq;
              ++cur_seq;
            }
          else
            cur_seq = 0;
        }
    }

  if (!frame_pointer_needed)
    {
      if (df_regs_ever_live_p (REG_Y))
        {
          ++live_seq;
          ++cur_seq;
        }
      else
        cur_seq = 0;

      if (df_regs_ever_live_p (REG_Y+1))
        {
          ++live_seq;
          ++cur_seq;
        }
      else
        cur_seq = 0;
    }
  else
    {
      cur_seq += 2;
      live_seq += 2;
    }
  return (cur_seq == live_seq) ? live_seq : 0;
}

/* Obtain the length sequence of insns.  */

int
get_sequence_length (rtx insns)
{
  rtx insn;
  int length;
  
  for (insn = insns, length = 0; insn; insn = NEXT_INSN (insn))
    length += get_attr_length (insn);
                
  return length;
}

/*  Implement INCOMING_RETURN_ADDR_RTX.  */

rtx
avr_incoming_return_addr_rtx (void)
{
  /* The return address is at the top of the stack.  Note that the push
     was via post-decrement, which means the actual address is off by one.  */
  return gen_frame_mem (HImode, plus_constant (stack_pointer_rtx, 1));
}

/*  Helper for expand_prologue.  Emit a push of a byte register.  */

static void
emit_push_byte (unsigned regno, bool frame_related_p)
{
  rtx mem, reg, insn;

  mem = gen_rtx_POST_DEC (HImode, stack_pointer_rtx);
  mem = gen_frame_mem (QImode, mem);
  reg = gen_rtx_REG (QImode, regno);

  insn = emit_insn (gen_rtx_SET (VOIDmode, mem, reg));
  if (frame_related_p)
    RTX_FRAME_RELATED_P (insn) = 1;

  cfun->machine->stack_usage++;
}


/*  Helper for expand_prologue.  Emit a push of a SFR via tmp_reg.
    SFR is a MEM representing the memory location of the SFR.
    If CLR_P then clear the SFR after the push using zero_reg.  */

static void
emit_push_sfr (rtx sfr, bool frame_related_p, bool clr_p)
{
  rtx insn;
  
  gcc_assert (MEM_P (sfr));

  /* IN __tmp_reg__, IO(SFR) */
  insn = emit_move_insn (tmp_reg_rtx, sfr);
  if (frame_related_p)
    RTX_FRAME_RELATED_P (insn) = 1;
  
  /* PUSH __tmp_reg__ */
  emit_push_byte (TMP_REGNO, frame_related_p);

  if (clr_p)
    {
      /* OUT IO(SFR), __zero_reg__ */
      insn = emit_move_insn (sfr, const0_rtx);
      if (frame_related_p)
        RTX_FRAME_RELATED_P (insn) = 1;
    }
}

static void
avr_prologue_setup_frame (HOST_WIDE_INT size, HARD_REG_SET set)
{
  rtx insn;
  bool isr_p = cfun->machine->is_interrupt || cfun->machine->is_signal;
  int live_seq = sequent_regs_live ();

  bool minimize = (TARGET_CALL_PROLOGUES
                   && live_seq
                   && !isr_p
                   && !cfun->machine->is_OS_task
                   && !cfun->machine->is_OS_main);
  
  if (minimize
      && (frame_pointer_needed
          || avr_outgoing_args_size() > 8
          || (AVR_2_BYTE_PC && live_seq > 6)
          || live_seq > 7)) 
    {
      rtx pattern;
      int first_reg, reg, offset;

      emit_move_insn (gen_rtx_REG (HImode, REG_X), 
                      gen_int_mode (size, HImode));

      pattern = gen_call_prologue_saves (gen_int_mode (live_seq, HImode),
                                         gen_int_mode (live_seq+size, HImode));
      insn = emit_insn (pattern);
      RTX_FRAME_RELATED_P (insn) = 1;

      /* Describe the effect of the unspec_volatile call to prologue_saves.
         Note that this formulation assumes that add_reg_note pushes the
         notes to the front.  Thus we build them in the reverse order of
         how we want dwarf2out to process them.  */

      /* The function does always set frame_pointer_rtx, but whether that
         is going to be permanent in the function is frame_pointer_needed.  */

      add_reg_note (insn, REG_CFA_ADJUST_CFA,
                    gen_rtx_SET (VOIDmode, (frame_pointer_needed
                                            ? frame_pointer_rtx
                                            : stack_pointer_rtx),
                                 plus_constant (stack_pointer_rtx,
                                                -(size + live_seq))));

      /* Note that live_seq always contains r28+r29, but the other
         registers to be saved are all below 18.  */

      first_reg = 18 - (live_seq - 2);

      for (reg = 29, offset = -live_seq + 1;
           reg >= first_reg;
           reg = (reg == 28 ? 17 : reg - 1), ++offset)
        {
          rtx m, r;

          m = gen_rtx_MEM (QImode, plus_constant (stack_pointer_rtx, offset));
          r = gen_rtx_REG (QImode, reg);
          add_reg_note (insn, REG_CFA_OFFSET, gen_rtx_SET (VOIDmode, m, r));
        }

      cfun->machine->stack_usage += size + live_seq;
    }
  else /* !minimize */
    {
      int reg;
      
      for (reg = 0; reg < 32; ++reg)
        if (TEST_HARD_REG_BIT (set, reg))
          emit_push_byte (reg, true);

      if (frame_pointer_needed
          && (!(cfun->machine->is_OS_task || cfun->machine->is_OS_main)))
        {
          /* Push frame pointer.  Always be consistent about the
             ordering of pushes -- epilogue_restores expects the
             register pair to be pushed low byte first.  */
          
          emit_push_byte (REG_Y, true);
          emit_push_byte (REG_Y + 1, true);
        }
          
      if (frame_pointer_needed
          && size == 0)
        {
          insn = emit_move_insn (frame_pointer_rtx, stack_pointer_rtx);
          RTX_FRAME_RELATED_P (insn) = 1;
        }
      
      if (size != 0)
        {
          /*  Creating a frame can be done by direct manipulation of the
              stack or via the frame pointer. These two methods are:
                  fp =  sp
                  fp -= size
                  sp =  fp
              or
                  sp -= size
                  fp =  sp    (*)
              the optimum method depends on function type, stack and
              frame size.  To avoid a complex logic, both methods are
              tested and shortest is selected.

              There is also the case where SIZE != 0 and no frame pointer is
              needed; this can occur if ACCUMULATE_OUTGOING_ARGS is on.
              In that case, insn (*) is not needed in that case.
              We use the X register as scratch. This is save because in X
              is call-clobbered.
                 In an interrupt routine, the case of SIZE != 0 together with
              !frame_pointer_needed can only occur if the function is not a
              leaf function and thus X has already been saved.  */
              
          int irq_state = -1;
          rtx fp_plus_insns, fp, my_fp;

          gcc_assert (frame_pointer_needed
                      || !isr_p
                      || !current_function_is_leaf);
          
          fp = my_fp = (frame_pointer_needed
                        ? frame_pointer_rtx
                        : gen_rtx_REG (Pmode, REG_X));
          
          if (AVR_HAVE_8BIT_SP)
            {
              /* The high byte (r29) does not change:
                 Prefer SUBI (1 cycle) over SBIW (2 cycles, same size).  */

              my_fp = all_regs_rtx[FRAME_POINTER_REGNUM];
            }

          /************  Method 1: Adjust frame pointer  ************/
          
          start_sequence ();

          /* Normally, the dwarf2out frame-related-expr interpreter does
             not expect to have the CFA change once the frame pointer is
             set up.  Thus, we avoid marking the move insn below and
             instead indicate that the entire operation is complete after
             the frame pointer subtraction is done.  */
          
          insn = emit_move_insn (fp, stack_pointer_rtx);
          if (frame_pointer_needed)
            {
              RTX_FRAME_RELATED_P (insn) = 1;
              add_reg_note (insn, REG_CFA_ADJUST_CFA,
                            gen_rtx_SET (VOIDmode, fp, stack_pointer_rtx));
            }

          insn = emit_move_insn (my_fp, plus_constant (my_fp, -size));
          if (frame_pointer_needed)
            {
              RTX_FRAME_RELATED_P (insn) = 1;
              add_reg_note (insn, REG_CFA_ADJUST_CFA,
                            gen_rtx_SET (VOIDmode, fp,
                                         plus_constant (fp, -size)));
            }
          
          /* Copy to stack pointer.  Note that since we've already
             changed the CFA to the frame pointer this operation
             need not be annotated if frame pointer is needed.
             Always move through unspec, see PR50063.
             For meaning of irq_state see movhi_sp_r insn.  */

          if (cfun->machine->is_interrupt)
            irq_state = 1;

          if (TARGET_NO_INTERRUPTS
              || cfun->machine->is_signal
              || cfun->machine->is_OS_main)
            irq_state = 0;

          if (AVR_HAVE_8BIT_SP)
            irq_state = 2;

          insn = emit_insn (gen_movhi_sp_r (stack_pointer_rtx,
                                            fp, GEN_INT (irq_state)));
          if (!frame_pointer_needed)
            {
              RTX_FRAME_RELATED_P (insn) = 1;
              add_reg_note (insn, REG_CFA_ADJUST_CFA,
                            gen_rtx_SET (VOIDmode, stack_pointer_rtx,
                                         plus_constant (stack_pointer_rtx,
                                                        -size)));
            }
          
          fp_plus_insns = get_insns ();
          end_sequence ();
          
          /************  Method 2: Adjust Stack pointer  ************/

          /* Stack adjustment by means of RCALL . and/or PUSH __TMP_REG__
             can only handle specific offsets.  */
          
          if (avr_sp_immediate_operand (gen_int_mode (-size, HImode), HImode))
            {
              rtx sp_plus_insns;
              
              start_sequence ();

              insn = emit_move_insn (stack_pointer_rtx,
                                     plus_constant (stack_pointer_rtx, -size));
              RTX_FRAME_RELATED_P (insn) = 1;
              add_reg_note (insn, REG_CFA_ADJUST_CFA,
                            gen_rtx_SET (VOIDmode, stack_pointer_rtx,
                                         plus_constant (stack_pointer_rtx,
                                                        -size)));
              if (frame_pointer_needed)
                {
                  insn = emit_move_insn (fp, stack_pointer_rtx);
                  RTX_FRAME_RELATED_P (insn) = 1;
                }

              sp_plus_insns = get_insns ();
              end_sequence ();

              /************ Use shortest method  ************/
                  
              emit_insn (get_sequence_length (sp_plus_insns)
                         < get_sequence_length (fp_plus_insns)
                         ? sp_plus_insns
                         : fp_plus_insns);
            }
          else
            {
              emit_insn (fp_plus_insns);
            }

          cfun->machine->stack_usage += size;
        } /* !minimize && size != 0 */
    } /* !minimize */
}


/*  Output function prologue.  */

void
expand_prologue (void)
{
  HARD_REG_SET set;
  HOST_WIDE_INT size;

  size = get_frame_size() + avr_outgoing_args_size();
  
  /* Init cfun->machine.  */
  cfun->machine->is_naked = avr_naked_function_p (current_function_decl);
  cfun->machine->is_interrupt = interrupt_function_p (current_function_decl);
  cfun->machine->is_signal = signal_function_p (current_function_decl);
  cfun->machine->is_OS_task = avr_OS_task_function_p (current_function_decl);
  cfun->machine->is_OS_main = avr_OS_main_function_p (current_function_decl);
  cfun->machine->stack_usage = 0;
  
  /* Prologue: naked.  */
  if (cfun->machine->is_naked)
    {
      return;
    }

  avr_regs_to_save (&set);

  if (cfun->machine->is_interrupt || cfun->machine->is_signal)
    {
      /* Enable interrupts.  */
      if (cfun->machine->is_interrupt)
        emit_insn (gen_enable_interrupt ());
        
      /* Push zero reg.  */
      emit_push_byte (ZERO_REGNO, true);

      /* Push tmp reg.  */
      emit_push_byte (TMP_REGNO, true);

      /* Push SREG.  */
      /* ??? There's no dwarf2 column reserved for SREG.  */
      emit_push_sfr (sreg_rtx, false, false /* clr */);

      /* Clear zero reg.  */
      emit_move_insn (zero_reg_rtx, const0_rtx);

      /* Prevent any attempt to delete the setting of ZERO_REG!  */
      emit_use (zero_reg_rtx);

      /* Push and clear RAMPD/X/Y/Z if present and low-part register is used.
         ??? There are no dwarf2 columns reserved for RAMPD/X/Y/Z.  */
      
      if (AVR_HAVE_RAMPD)
        emit_push_sfr (rampd_rtx, false /* frame-related */, true /* clr */);

      if (AVR_HAVE_RAMPX
          && TEST_HARD_REG_BIT (set, REG_X)
          && TEST_HARD_REG_BIT (set, REG_X + 1))
        {
          emit_push_sfr (rampx_rtx, false /* frame-related */, true /* clr */);
        }

      if (AVR_HAVE_RAMPY
          && (frame_pointer_needed
              || (TEST_HARD_REG_BIT (set, REG_Y)
                  && TEST_HARD_REG_BIT (set, REG_Y + 1))))
        {
          emit_push_sfr (rampy_rtx, false /* frame-related */, true /* clr */);
        }

      if (AVR_HAVE_RAMPZ 
          && TEST_HARD_REG_BIT (set, REG_Z)
          && TEST_HARD_REG_BIT (set, REG_Z + 1))
        {
          emit_push_sfr (rampz_rtx, false /* frame-related */, true /* clr */);
        }
    }  /* is_interrupt is_signal */

  avr_prologue_setup_frame (size, set);
  
  if (flag_stack_usage_info)
    current_function_static_stack_size = cfun->machine->stack_usage;
}

/* Output summary at end of function prologue.  */

static void
avr_asm_function_end_prologue (FILE *file)
{
  if (cfun->machine->is_naked)
    {
      fputs ("/* prologue: naked */\n", file);
    }
  else
    {
      if (cfun->machine->is_interrupt)
        {
          fputs ("/* prologue: Interrupt */\n", file);
        }
      else if (cfun->machine->is_signal)
        {
          fputs ("/* prologue: Signal */\n", file);
        }
      else
        fputs ("/* prologue: function */\n", file);
    }

  if (ACCUMULATE_OUTGOING_ARGS)
    fprintf (file, "/* outgoing args size = %d */\n",
             avr_outgoing_args_size());

  fprintf (file, "/* frame size = " HOST_WIDE_INT_PRINT_DEC " */\n",
                 get_frame_size());
  fprintf (file, "/* stack size = %d */\n",
                 cfun->machine->stack_usage);
  /* Create symbol stack offset here so all functions have it. Add 1 to stack
     usage for offset so that SP + .L__stack_offset = return address.  */
  fprintf (file, ".L__stack_usage = %d\n", cfun->machine->stack_usage);
}


/* Implement EPILOGUE_USES.  */

int
avr_epilogue_uses (int regno ATTRIBUTE_UNUSED)
{
  if (reload_completed 
      && cfun->machine
      && (cfun->machine->is_interrupt || cfun->machine->is_signal))
    return 1;
  return 0;
}

/*  Helper for expand_epilogue.  Emit a pop of a byte register.  */

static void
emit_pop_byte (unsigned regno)
{
  rtx mem, reg;

  mem = gen_rtx_PRE_INC (HImode, stack_pointer_rtx);
  mem = gen_frame_mem (QImode, mem);
  reg = gen_rtx_REG (QImode, regno);

  emit_insn (gen_rtx_SET (VOIDmode, reg, mem));
}

/*  Output RTL epilogue.  */

void
expand_epilogue (bool sibcall_p)
{
  int reg;
  int live_seq;
  HARD_REG_SET set;      
  int minimize;
  HOST_WIDE_INT size;
  bool isr_p = cfun->machine->is_interrupt || cfun->machine->is_signal;

  size = get_frame_size() + avr_outgoing_args_size();
  
  /* epilogue: naked  */
  if (cfun->machine->is_naked)
    {
      gcc_assert (!sibcall_p);
      
      emit_jump_insn (gen_return ());
      return;
    }

  avr_regs_to_save (&set);
  live_seq = sequent_regs_live ();
  
  minimize = (TARGET_CALL_PROLOGUES
              && live_seq
              && !isr_p
              && !cfun->machine->is_OS_task
              && !cfun->machine->is_OS_main);
  
  if (minimize
      && (live_seq > 4
          || frame_pointer_needed
          || size))
    {
      /*  Get rid of frame.  */
      
      if (!frame_pointer_needed)
        {
          emit_move_insn (frame_pointer_rtx, stack_pointer_rtx);
        }

      if (size)
        {
          emit_move_insn (frame_pointer_rtx,
                          plus_constant (frame_pointer_rtx, size));
        }
        
      emit_insn (gen_epilogue_restores (gen_int_mode (live_seq, HImode)));
      return;
    }
      
  if (size)
    {
      /* Try two methods to adjust stack and select shortest.  */

      int irq_state = -1;
      rtx fp, my_fp;
      rtx fp_plus_insns;

      gcc_assert (frame_pointer_needed
                  || !isr_p
                  || !current_function_is_leaf);
      
      fp = my_fp = (frame_pointer_needed
                    ? frame_pointer_rtx
                    : gen_rtx_REG (Pmode, REG_X));

      if (AVR_HAVE_8BIT_SP)
        {
          /* The high byte (r29) does not change:
             Prefer SUBI (1 cycle) over SBIW (2 cycles).  */
                  
          my_fp = all_regs_rtx[FRAME_POINTER_REGNUM];
        }
              
      /********** Method 1: Adjust fp register  **********/
              
      start_sequence ();

      if (!frame_pointer_needed)
        emit_move_insn (fp, stack_pointer_rtx);

      emit_move_insn (my_fp, plus_constant (my_fp, size));

      /* Copy to stack pointer.  */

      if (TARGET_NO_INTERRUPTS)
        irq_state = 0;

      if (AVR_HAVE_8BIT_SP)
        irq_state = 2;

      emit_insn (gen_movhi_sp_r (stack_pointer_rtx, fp,
                                 GEN_INT (irq_state)));

      fp_plus_insns = get_insns ();
      end_sequence ();        

      /********** Method 2: Adjust Stack pointer  **********/
      
      if (avr_sp_immediate_operand (gen_int_mode (size, HImode), HImode))
        {
          rtx sp_plus_insns;

          start_sequence ();

          emit_move_insn (stack_pointer_rtx,
                          plus_constant (stack_pointer_rtx, size));

          sp_plus_insns = get_insns ();
          end_sequence ();

          /************ Use shortest method  ************/
          
          emit_insn (get_sequence_length (sp_plus_insns)
                     < get_sequence_length (fp_plus_insns)
                     ? sp_plus_insns
                     : fp_plus_insns);
        }
      else
        emit_insn (fp_plus_insns);
    } /* size != 0 */
          
  if (frame_pointer_needed
      && !(cfun->machine->is_OS_task || cfun->machine->is_OS_main))
    {
      /* Restore previous frame_pointer.  See expand_prologue for
         rationale for not using pophi.  */
              
      emit_pop_byte (REG_Y + 1);
      emit_pop_byte (REG_Y);
    }

  /* Restore used registers.  */
  
  for (reg = 31; reg >= 0; --reg)
    if (TEST_HARD_REG_BIT (set, reg))
      emit_pop_byte (reg);

  if (isr_p)
    {
      /* Restore RAMPZ/Y/X/D using tmp_reg as scratch.
         The conditions to restore them must be tha same as in prologue.  */
      
      if (AVR_HAVE_RAMPX
          && TEST_HARD_REG_BIT (set, REG_X)
          && TEST_HARD_REG_BIT (set, REG_X + 1))
        {
          emit_pop_byte (TMP_REGNO);
          emit_move_insn (rampx_rtx, tmp_reg_rtx);
        }

      if (AVR_HAVE_RAMPY
          && (frame_pointer_needed
              || (TEST_HARD_REG_BIT (set, REG_Y)
                  && TEST_HARD_REG_BIT (set, REG_Y + 1))))
        {
          emit_pop_byte (TMP_REGNO);
          emit_move_insn (rampy_rtx, tmp_reg_rtx);
        }

      if (AVR_HAVE_RAMPZ
          && TEST_HARD_REG_BIT (set, REG_Z)
          && TEST_HARD_REG_BIT (set, REG_Z + 1))
        {
          emit_pop_byte (TMP_REGNO);
          emit_move_insn (rampz_rtx, tmp_reg_rtx);
        }

      if (AVR_HAVE_RAMPD)
        {
          emit_pop_byte (TMP_REGNO);
          emit_move_insn (rampd_rtx, tmp_reg_rtx);
        }

      /* Restore SREG using tmp_reg as scratch.  */
      
      emit_pop_byte (TMP_REGNO);
      emit_move_insn (sreg_rtx, tmp_reg_rtx);

      /* Restore tmp REG.  */
      emit_pop_byte (TMP_REGNO);

      /* Restore zero REG.  */
      emit_pop_byte (ZERO_REGNO);
    }

  if (!sibcall_p)
    emit_jump_insn (gen_return ());
}

/* Output summary messages at beginning of function epilogue.  */

static void
avr_asm_function_begin_epilogue (FILE *file)
{
  fprintf (file, "/* epilogue start */\n");
}


/* Implement TARGET_CANNOT_MODITY_JUMPS_P */

static bool
avr_cannot_modify_jumps_p (void)
{

  /* Naked Functions must not have any instructions after
     their epilogue, see PR42240 */
     
  if (reload_completed
      && cfun->machine
      && cfun->machine->is_naked)
    {
      return true;
    }

  return false;
}


/* Helper function for `avr_legitimate_address_p'.  */

static inline bool
avr_reg_ok_for_addr_p (rtx reg, addr_space_t as,
                       RTX_CODE outer_code, bool strict)
{
  return (REG_P (reg)
          && (avr_regno_mode_code_ok_for_base_p (REGNO (reg), QImode,
                                                 as, outer_code, UNKNOWN)
              || (!strict
                  && REGNO (reg) >= FIRST_PSEUDO_REGISTER)));
}


/* Return nonzero if X (an RTX) is a legitimate memory address on the target
   machine for a memory operand of mode MODE.  */

static bool
avr_legitimate_address_p (enum machine_mode mode, rtx x, bool strict)
{
  bool ok = CONSTANT_ADDRESS_P (x);
  
  switch (GET_CODE (x))
    {
    case REG:
      ok = avr_reg_ok_for_addr_p (x, ADDR_SPACE_GENERIC,
                                  MEM, strict);

      if (strict
          && DImode == mode
          && REG_X == REGNO (x))
        {
          ok = false;
        }
      break;

    case POST_INC:
    case PRE_DEC:
      ok = avr_reg_ok_for_addr_p (XEXP (x, 0), ADDR_SPACE_GENERIC,
                                  GET_CODE (x), strict);
      break;

    case PLUS:
      {
        rtx reg = XEXP (x, 0);
        rtx op1 = XEXP (x, 1);
        
        if (REG_P (reg)
            && CONST_INT_P (op1)
            && INTVAL (op1) >= 0)
          {
            bool fit = IN_RANGE (INTVAL (op1), 0, MAX_LD_OFFSET (mode));

            if (fit)
              {
                ok = (! strict
                      || avr_reg_ok_for_addr_p (reg, ADDR_SPACE_GENERIC,
                                                PLUS, strict));
          
                if (reg == frame_pointer_rtx
                    || reg == arg_pointer_rtx)
                  {
                    ok = true;
                  }
              }
            else if (frame_pointer_needed
                     && reg == frame_pointer_rtx)
              {
                ok = true;
              }
          }
      }
      break;
      
    default:
      break;
    }
  
  if (avr_log.legitimate_address_p)
    {
      avr_edump ("\n%?: ret=%d, mode=%m strict=%d "
                 "reload_completed=%d reload_in_progress=%d %s:",
                 ok, mode, strict, reload_completed, reload_in_progress,
                 reg_renumber ? "(reg_renumber)" : "");
      
      if (GET_CODE (x) == PLUS
          && REG_P (XEXP (x, 0))
          && CONST_INT_P (XEXP (x, 1))
          && IN_RANGE (INTVAL (XEXP (x, 1)), 0, MAX_LD_OFFSET (mode))
          && reg_renumber)
        {
          avr_edump ("(r%d ---> r%d)", REGNO (XEXP (x, 0)),
                     true_regnum (XEXP (x, 0)));
        }
      
      avr_edump ("\n%r\n", x);
    }
  
  return ok;
}


/* Former implementation of TARGET_LEGITIMIZE_ADDRESS,
   now only a helper for avr_addr_space_legitimize_address.  */
/* Attempts to replace X with a valid
   memory address for an operand of mode MODE  */

static rtx
avr_legitimize_address (rtx x, rtx oldx, enum machine_mode mode)
{
  bool big_offset_p = false;
  
  x = oldx;
  
  if (GET_CODE (oldx) == PLUS
      && REG_P (XEXP (oldx, 0)))
    {
      if (REG_P (XEXP (oldx, 1)))
        x = force_reg (GET_MODE (oldx), oldx);
      else if (CONST_INT_P (XEXP (oldx, 1)))
        {
          int offs = INTVAL (XEXP (oldx, 1));
          if (frame_pointer_rtx != XEXP (oldx, 0)
              && offs > MAX_LD_OFFSET (mode))
            {
              big_offset_p = true;
              x = force_reg (GET_MODE (oldx), oldx);
            }
        }
    }
  
  if (avr_log.legitimize_address)
    {
      avr_edump ("\n%?: mode=%m\n %r\n", mode, oldx);

      if (x != oldx)
        avr_edump (" %s --> %r\n", big_offset_p ? "(big offset)" : "", x);
    }

  return x;
}


/* Implement `LEGITIMIZE_RELOAD_ADDRESS'.  */
/* This will allow register R26/27 to be used where it is no worse than normal
   base pointers R28/29 or R30/31.  For example, if base offset is greater
   than 63 bytes or for R++ or --R addressing.  */

rtx
avr_legitimize_reload_address (rtx *px, enum machine_mode mode,
                               int opnum, int type, int addr_type,
                               int ind_levels ATTRIBUTE_UNUSED,
                               rtx (*mk_memloc)(rtx,int))
{
  rtx x = *px;
  
  if (avr_log.legitimize_reload_address)
    avr_edump ("\n%?:%m %r\n", mode, x);
  
  if (1 && (GET_CODE (x) == POST_INC
            || GET_CODE (x) == PRE_DEC))
    {
      push_reload (XEXP (x, 0), XEXP (x, 0), &XEXP (x, 0), &XEXP (x, 0),
                   POINTER_REGS, GET_MODE (x), GET_MODE (x), 0, 0,
                   opnum, RELOAD_OTHER);
      
      if (avr_log.legitimize_reload_address)
        avr_edump (" RCLASS.1 = %R\n IN = %r\n OUT = %r\n",
                   POINTER_REGS, XEXP (x, 0), XEXP (x, 0));
      
      return x;
    }
  
  if (GET_CODE (x) == PLUS
      && REG_P (XEXP (x, 0))
      && 0 == reg_equiv_constant (REGNO (XEXP (x, 0)))
      && CONST_INT_P (XEXP (x, 1))
      && INTVAL (XEXP (x, 1)) >= 1)
    {
      bool fit = INTVAL (XEXP (x, 1)) <= MAX_LD_OFFSET (mode);
      
      if (fit)
        {
          if (reg_equiv_address (REGNO (XEXP (x, 0))) != 0)
            {
              int regno = REGNO (XEXP (x, 0));
              rtx mem = mk_memloc (x, regno);
              
              push_reload (XEXP (mem, 0), NULL_RTX, &XEXP (mem, 0), NULL,
                           POINTER_REGS, Pmode, VOIDmode, 0, 0,
                           1, addr_type);
              
              if (avr_log.legitimize_reload_address)
                avr_edump (" RCLASS.2 = %R\n IN = %r\n OUT = %r\n",
                           POINTER_REGS, XEXP (mem, 0), NULL_RTX);
              
              push_reload (mem, NULL_RTX, &XEXP (x, 0), NULL,
                           BASE_POINTER_REGS, GET_MODE (x), VOIDmode, 0, 0,
                           opnum, type);
              
              if (avr_log.legitimize_reload_address)
                avr_edump (" RCLASS.2 = %R\n IN = %r\n OUT = %r\n",
                           BASE_POINTER_REGS, mem, NULL_RTX);
              
              return x;
            }
        }
      else if (! (frame_pointer_needed
                  && XEXP (x, 0) == frame_pointer_rtx))
        {
          push_reload (x, NULL_RTX, px, NULL,
                       POINTER_REGS, GET_MODE (x), VOIDmode, 0, 0,
                       opnum, type);
          
          if (avr_log.legitimize_reload_address)
            avr_edump (" RCLASS.3 = %R\n IN = %r\n OUT = %r\n",
                       POINTER_REGS, x, NULL_RTX);
          
          return x;
        }
    }
  
  return NULL_RTX;
}


/* Helper function to print assembler resp. track instruction
   sequence lengths.  Always return "".
   
   If PLEN == NULL:
       Output assembler code from template TPL with operands supplied
       by OPERANDS.  This is just forwarding to output_asm_insn.
   
   If PLEN != NULL:
       If N_WORDS >= 0  Add N_WORDS to *PLEN.
       If N_WORDS < 0   Set *PLEN to -N_WORDS.
       Don't output anything.
*/

static const char*
avr_asm_len (const char* tpl, rtx* operands, int* plen, int n_words)
{
  if (NULL == plen)
    {
      output_asm_insn (tpl, operands);
    }
  else
    {
      if (n_words < 0)
        *plen = -n_words;
      else
        *plen += n_words;
    }

  return "";
}


/* Return a pointer register name as a string.  */

static const char *
ptrreg_to_str (int regno)
{
  switch (regno)
    {
    case REG_X: return "X";
    case REG_Y: return "Y";
    case REG_Z: return "Z";
    default:
      output_operand_lossage ("address operand requires constraint for"
                              " X, Y, or Z register");
    }
  return NULL;
}

/* Return the condition name as a string.
   Used in conditional jump constructing  */

static const char *
cond_string (enum rtx_code code)
{
  switch (code)
    {
    case NE:
      return "ne";
    case EQ:
      return "eq";
    case GE:
      if (cc_prev_status.flags & CC_OVERFLOW_UNUSABLE)
        return "pl";
      else
        return "ge";
    case LT:
      if (cc_prev_status.flags & CC_OVERFLOW_UNUSABLE)
        return "mi";
      else
        return "lt";
    case GEU:
      return "sh";
    case LTU:
      return "lo";
    default:
      gcc_unreachable ();
    }

  return "";
}


/* Implement `TARGET_PRINT_OPERAND_ADDRESS'.  */
/* Output ADDR to FILE as address.  */

static void
avr_print_operand_address (FILE *file, rtx addr)
{
  switch (GET_CODE (addr))
    {
    case REG:
      fprintf (file, ptrreg_to_str (REGNO (addr)));
      break;

    case PRE_DEC:
      fprintf (file, "-%s", ptrreg_to_str (REGNO (XEXP (addr, 0))));
      break;

    case POST_INC:
      fprintf (file, "%s+", ptrreg_to_str (REGNO (XEXP (addr, 0))));
      break;

    default:
      if (CONSTANT_ADDRESS_P (addr)
          && text_segment_operand (addr, VOIDmode))
        {
          rtx x = addr;
          if (GET_CODE (x) == CONST)
            x = XEXP (x, 0);
          if (GET_CODE (x) == PLUS && GET_CODE (XEXP (x,1)) == CONST_INT)
            {
              /* Assembler gs() will implant word address. Make offset 
                 a byte offset inside gs() for assembler. This is 
                 needed because the more logical (constant+gs(sym)) is not 
                 accepted by gas. For 128K and lower devices this is ok.
                 For large devices it will create a Trampoline to offset
                 from symbol which may not be what the user really wanted.  */
              fprintf (file, "gs(");
              output_addr_const (file, XEXP (x,0));
              fprintf (file, "+" HOST_WIDE_INT_PRINT_DEC ")",
                       2 * INTVAL (XEXP (x, 1)));
              if (AVR_3_BYTE_PC)
                if (warning (0, "pointer offset from symbol maybe incorrect"))
                  {
                    output_addr_const (stderr, addr);
                    fprintf(stderr,"\n");
                  }
            }
          else
            {
              fprintf (file, "gs(");
              output_addr_const (file, addr);
              fprintf (file, ")");
            }
        }
      else
        output_addr_const (file, addr);
    }
}


/* Implement `TARGET_PRINT_OPERAND_PUNCT_VALID_P'.  */

static bool
avr_print_operand_punct_valid_p (unsigned char code)
{
  return code == '~' || code == '!';
}


/* Implement `TARGET_PRINT_OPERAND'.  */
/* Output X as assembler operand to file FILE.
   For a description of supported %-codes, see top of avr.md.  */

static void
avr_print_operand (FILE *file, rtx x, int code)
{
  int abcd = 0;

  if (code >= 'A' && code <= 'D')
    abcd = code - 'A';

  if (code == '~')
    {
      if (!AVR_HAVE_JMP_CALL)
        fputc ('r', file);
    }
  else if (code == '!')
    {
      if (AVR_HAVE_EIJMP_EICALL)
        fputc ('e', file);
    }
  else if (code == 't'
           || code == 'T')
    {
      static int t_regno = -1;
      static int t_nbits = -1;

      if (REG_P (x) && t_regno < 0 && code == 'T')
        {
          t_regno = REGNO (x);
          t_nbits = GET_MODE_BITSIZE (GET_MODE (x));
        }
      else if (CONST_INT_P (x) && t_regno >= 0
               && IN_RANGE (INTVAL (x), 0, t_nbits - 1))
        {
          int bpos = INTVAL (x);

          fprintf (file, "%s", reg_names[t_regno + bpos / 8]);
          if (code == 'T')
            fprintf (file, ",%d", bpos % 8);

          t_regno = -1;
        }
      else
        fatal_insn ("operands to %T/%t must be reg + const_int:", x);
    }
  else if (REG_P (x))
    {
      if (x == zero_reg_rtx)
        fprintf (file, "__zero_reg__");
      else
        fprintf (file, reg_names[true_regnum (x) + abcd]);
    }
  else if (CONST_INT_P (x))
    {
      HOST_WIDE_INT ival = INTVAL (x);
        
      if ('i' != code)
        fprintf (file, HOST_WIDE_INT_PRINT_DEC, ival + abcd);
      else if (low_io_address_operand (x, VOIDmode)
               || high_io_address_operand (x, VOIDmode))
        {
          if (AVR_HAVE_RAMPZ && ival == avr_addr.rampz)
            fprintf (file, "__RAMPZ__");
          else if (AVR_HAVE_RAMPY && ival == avr_addr.rampy)
            fprintf (file, "__RAMPY__");
          else if (AVR_HAVE_RAMPX && ival == avr_addr.rampx)
            fprintf (file, "__RAMPX__");
          else if (AVR_HAVE_RAMPD && ival == avr_addr.rampd)
            fprintf (file, "__RAMPD__");
          else if (AVR_XMEGA && ival == avr_addr.ccp)
            fprintf (file, "__CCP__");
          else if (ival == avr_addr.sreg)   fprintf (file, "__SREG__");
          else if (ival == avr_addr.sp_l)   fprintf (file, "__SP_L__");
          else if (ival == avr_addr.sp_h)   fprintf (file, "__SP_H__");
          else
            {
              fprintf (file, HOST_WIDE_INT_PRINT_HEX,
                       ival - avr_current_arch->sfr_offset);
            }
        }
      else
        fatal_insn ("bad address, not an I/O address:", x);
    }
  else if (MEM_P (x))
    {
      rtx addr = XEXP (x, 0);
      
      if (code == 'm')
        {
          if (!CONSTANT_P (addr))
            fatal_insn ("bad address, not a constant:", addr);
          /* Assembler template with m-code is data - not progmem section */
          if (text_segment_operand (addr, VOIDmode))
            if (warning (0, "accessing data memory with"
                         " program memory address"))
              {
                output_addr_const (stderr, addr);
                fprintf(stderr,"\n");
              }
          output_addr_const (file, addr);
        }
      else if (code == 'i')
        {
          avr_print_operand (file, addr, 'i');
        }
      else if (code == 'o')
        {
          if (GET_CODE (addr) != PLUS)
            fatal_insn ("bad address, not (reg+disp):", addr);

          avr_print_operand (file, XEXP (addr, 1), 0);
        }
      else if (code == 'p' || code == 'r')
        {
          if (GET_CODE (addr) != POST_INC && GET_CODE (addr) != PRE_DEC)
            fatal_insn ("bad address, not post_inc or pre_dec:", addr);
          
          if (code == 'p')
            avr_print_operand_address (file, XEXP (addr, 0));  /* X, Y, Z */
          else
            avr_print_operand (file, XEXP (addr, 0), 0);  /* r26, r28, r30 */
        }
      else if (GET_CODE (addr) == PLUS)
        {
          avr_print_operand_address (file, XEXP (addr,0));
          if (REGNO (XEXP (addr, 0)) == REG_X)
            fatal_insn ("internal compiler error.  Bad address:"
                        ,addr);
          fputc ('+', file);
          avr_print_operand (file, XEXP (addr,1), code);
        }
      else
        avr_print_operand_address (file, addr);
    }
  else if (code == 'i')
    {
      fatal_insn ("bad address, not an I/O address:", x);
    }
  else if (code == 'x')
    {
      /* Constant progmem address - like used in jmp or call */
      if (0 == text_segment_operand (x, VOIDmode))
        if (warning (0, "accessing program memory"
                     " with data memory address"))
          {
            output_addr_const (stderr, x);
            fprintf(stderr,"\n");
          }
      /* Use normal symbol for direct address no linker trampoline needed */
      output_addr_const (file, x);
    }
  else if (GET_CODE (x) == CONST_DOUBLE)
    {
      long val;
      REAL_VALUE_TYPE rv;
      if (GET_MODE (x) != SFmode)
        fatal_insn ("internal compiler error.  Unknown mode:", x);
      REAL_VALUE_FROM_CONST_DOUBLE (rv, x);
      REAL_VALUE_TO_TARGET_SINGLE (rv, val);
      fprintf (file, "0x%lx", val);
    }
  else if (GET_CODE (x) == CONST_STRING)
    fputs (XSTR (x, 0), file);
  else if (code == 'j')
    fputs (cond_string (GET_CODE (x)), file);
  else if (code == 'k')
    fputs (cond_string (reverse_condition (GET_CODE (x))), file);
  else
    avr_print_operand_address (file, x);
}

/* Update the condition code in the INSN.  */

void
notice_update_cc (rtx body ATTRIBUTE_UNUSED, rtx insn)
{
  rtx set;
  enum attr_cc cc = get_attr_cc (insn);
  
  switch (cc)
    {
    default:
      break;

    case CC_OUT_PLUS:
    case CC_OUT_PLUS_NOCLOBBER:
    case CC_LDI:
      {
        rtx *op = recog_data.operand;
        int len_dummy, icc;
        
        /* Extract insn's operands.  */
        extract_constrain_insn_cached (insn);

        switch (cc)
          {
          default:
            gcc_unreachable();
            
          case CC_OUT_PLUS:
            avr_out_plus (op, &len_dummy, &icc);
            cc = (enum attr_cc) icc;
            break;
            
          case CC_OUT_PLUS_NOCLOBBER:
            avr_out_plus_noclobber (op, &len_dummy, &icc);
            cc = (enum attr_cc) icc;
            break;

          case CC_LDI:

            cc = (op[1] == CONST0_RTX (GET_MODE (op[0]))
                  && reg_overlap_mentioned_p (op[0], zero_reg_rtx))
              /* Loading zero-reg with 0 uses CLI and thus clobbers cc0.  */
              ? CC_CLOBBER
              /* Any other "r,rL" combination does not alter cc0.  */
              : CC_NONE;
            
            break;
          } /* inner switch */

        break;
      }
    } /* outer swicth */

  switch (cc)
    {
    default:
      /* Special values like CC_OUT_PLUS from above have been
         mapped to "standard" CC_* values so we never come here.  */
      
      gcc_unreachable();
      break;
      
    case CC_NONE:
      /* Insn does not affect CC at all.  */
      break;

    case CC_SET_N:
      CC_STATUS_INIT;
      break;

    case CC_SET_ZN:
      set = single_set (insn);
      CC_STATUS_INIT;
      if (set)
        {
          cc_status.flags |= CC_NO_OVERFLOW;
          cc_status.value1 = SET_DEST (set);
        }
      break;

    case CC_SET_CZN:
      /* Insn sets the Z,N,C flags of CC to recog_operand[0].
         The V flag may or may not be known but that's ok because
         alter_cond will change tests to use EQ/NE.  */
      set = single_set (insn);
      CC_STATUS_INIT;
      if (set)
        {
          cc_status.value1 = SET_DEST (set);
          cc_status.flags |= CC_OVERFLOW_UNUSABLE;
        }
      break;

    case CC_COMPARE:
      set = single_set (insn);
      CC_STATUS_INIT;
      if (set)
        cc_status.value1 = SET_SRC (set);
      break;
      
    case CC_CLOBBER:
      /* Insn doesn't leave CC in a usable state.  */
      CC_STATUS_INIT;
      break;
    }
}

/* Choose mode for jump insn:
   1 - relative jump in range -63 <= x <= 62 ;
   2 - relative jump in range -2046 <= x <= 2045 ;
   3 - absolute jump (only for ATmega[16]03).  */

int
avr_jump_mode (rtx x, rtx insn)
{
  int dest_addr = INSN_ADDRESSES (INSN_UID (GET_CODE (x) == LABEL_REF
                                            ? XEXP (x, 0) : x));
  int cur_addr = INSN_ADDRESSES (INSN_UID (insn));
  int jump_distance = cur_addr - dest_addr;
  
  if (-63 <= jump_distance && jump_distance <= 62)
    return 1;
  else if (-2046 <= jump_distance && jump_distance <= 2045)
    return 2;
  else if (AVR_HAVE_JMP_CALL)
    return 3;
  
  return 2;
}

/* return an AVR condition jump commands.
   X is a comparison RTX.
   LEN is a number returned by avr_jump_mode function.
   if REVERSE nonzero then condition code in X must be reversed.  */

const char *
ret_cond_branch (rtx x, int len, int reverse)
{
  RTX_CODE cond = reverse ? reverse_condition (GET_CODE (x)) : GET_CODE (x);
  
  switch (cond)
    {
    case GT:
      if (cc_prev_status.flags & CC_OVERFLOW_UNUSABLE)
        return (len == 1 ? ("breq .+2" CR_TAB
                            "brpl %0") :
                len == 2 ? ("breq .+4" CR_TAB
                            "brmi .+2" CR_TAB
                            "rjmp %0") :
                ("breq .+6" CR_TAB
                 "brmi .+4" CR_TAB
                 "jmp %0"));
          
      else
        return (len == 1 ? ("breq .+2" CR_TAB
                            "brge %0") :
                len == 2 ? ("breq .+4" CR_TAB
                            "brlt .+2" CR_TAB
                            "rjmp %0") :
                ("breq .+6" CR_TAB
                 "brlt .+4" CR_TAB
                 "jmp %0"));
    case GTU:
      return (len == 1 ? ("breq .+2" CR_TAB
                          "brsh %0") :
              len == 2 ? ("breq .+4" CR_TAB
                          "brlo .+2" CR_TAB
                          "rjmp %0") :
              ("breq .+6" CR_TAB
               "brlo .+4" CR_TAB
               "jmp %0"));
    case LE:
      if (cc_prev_status.flags & CC_OVERFLOW_UNUSABLE)
        return (len == 1 ? ("breq %0" CR_TAB
                            "brmi %0") :
                len == 2 ? ("breq .+2" CR_TAB
                            "brpl .+2" CR_TAB
                            "rjmp %0") :
                ("breq .+2" CR_TAB
                 "brpl .+4" CR_TAB
                 "jmp %0"));
      else
        return (len == 1 ? ("breq %0" CR_TAB
                            "brlt %0") :
                len == 2 ? ("breq .+2" CR_TAB
                            "brge .+2" CR_TAB
                            "rjmp %0") :
                ("breq .+2" CR_TAB
                 "brge .+4" CR_TAB
                 "jmp %0"));
    case LEU:
      return (len == 1 ? ("breq %0" CR_TAB
                          "brlo %0") :
              len == 2 ? ("breq .+2" CR_TAB
                          "brsh .+2" CR_TAB
                          "rjmp %0") :
              ("breq .+2" CR_TAB
               "brsh .+4" CR_TAB
               "jmp %0"));
    default:
      if (reverse)
        {
          switch (len)
            {
            case 1:
              return "br%k1 %0";
            case 2:
              return ("br%j1 .+2" CR_TAB
                      "rjmp %0");
            default:
              return ("br%j1 .+4" CR_TAB
                      "jmp %0");
            }
        }
      else
        {
          switch (len)
            {
            case 1:
              return "br%j1 %0";
            case 2:
              return ("br%k1 .+2" CR_TAB
                      "rjmp %0");
            default:
              return ("br%k1 .+4" CR_TAB
                      "jmp %0");
            }
        }
    }
  return "";
}

/* Output insn cost for next insn.  */

void
final_prescan_insn (rtx insn, rtx *operand ATTRIBUTE_UNUSED,
                    int num_operands ATTRIBUTE_UNUSED)
{
  if (avr_log.rtx_costs)
    {
      rtx set = single_set (insn);

      if (set)
        fprintf (asm_out_file, "/* DEBUG: cost = %d.  */\n",
                 set_src_cost (SET_SRC (set), optimize_insn_for_speed_p ()));
      else
        fprintf (asm_out_file, "/* DEBUG: pattern-cost = %d.  */\n",
                 rtx_cost (PATTERN (insn), INSN, 0,
                           optimize_insn_for_speed_p()));
    }
}

/* Return 0 if undefined, 1 if always true or always false.  */

int
avr_simplify_comparison_p (enum machine_mode mode, RTX_CODE op, rtx x)
{
  unsigned int max = (mode == QImode ? 0xff :
                      mode == HImode ? 0xffff :
                      mode == PSImode ? 0xffffff :
                      mode == SImode ? 0xffffffff : 0);
  if (max && op && GET_CODE (x) == CONST_INT)
    {
      if (unsigned_condition (op) != op)
        max >>= 1;

      if (max != (INTVAL (x) & max)
          && INTVAL (x) != 0xff)
        return 1;
    }
  return 0;
}


/* Returns nonzero if REGNO is the number of a hard
   register in which function arguments are sometimes passed.  */

int
function_arg_regno_p(int r)
{
  return (r >= 8 && r <= 25);
}

/* Initializing the variable cum for the state at the beginning
   of the argument list.  */

void
init_cumulative_args (CUMULATIVE_ARGS *cum, tree fntype, rtx libname,
                      tree fndecl ATTRIBUTE_UNUSED)
{
  cum->nregs = 18;
  cum->regno = FIRST_CUM_REG;
  if (!libname && stdarg_p (fntype))
    cum->nregs = 0;

  /* Assume the calle may be tail called */
  
  cfun->machine->sibcall_fails = 0;
}

/* Returns the number of registers to allocate for a function argument.  */

static int
avr_num_arg_regs (enum machine_mode mode, const_tree type)
{
  int size;

  if (mode == BLKmode)
    size = int_size_in_bytes (type);
  else
    size = GET_MODE_SIZE (mode);

  /* Align all function arguments to start in even-numbered registers.
     Odd-sized arguments leave holes above them.  */

  return (size + 1) & ~1;
}

/* Controls whether a function argument is passed
   in a register, and which register.  */

static rtx
avr_function_arg (cumulative_args_t cum_v, enum machine_mode mode,
                  const_tree type, bool named ATTRIBUTE_UNUSED)
{
  CUMULATIVE_ARGS *cum = get_cumulative_args (cum_v);
  int bytes = avr_num_arg_regs (mode, type);

  if (cum->nregs && bytes <= cum->nregs)
    return gen_rtx_REG (mode, cum->regno - bytes);

  return NULL_RTX;
}

/* Update the summarizer variable CUM to advance past an argument
   in the argument list.  */
   
static void
avr_function_arg_advance (cumulative_args_t cum_v, enum machine_mode mode,
                          const_tree type, bool named ATTRIBUTE_UNUSED)
{
  CUMULATIVE_ARGS *cum = get_cumulative_args (cum_v);
  int bytes = avr_num_arg_regs (mode, type);

  cum->nregs -= bytes;
  cum->regno -= bytes;

  /* A parameter is being passed in a call-saved register. As the original
     contents of these regs has to be restored before leaving the function,
     a function must not pass arguments in call-saved regs in order to get
     tail-called. */
  
  if (cum->regno >= 8
      && cum->nregs >= 0
      && !call_used_regs[cum->regno])
    {
      /* FIXME: We ship info on failing tail-call in struct machine_function.
         This uses internals of calls.c:expand_call() and the way args_so_far
         is used. targetm.function_ok_for_sibcall() needs to be extended to
         pass &args_so_far, too. At present, CUMULATIVE_ARGS is target
         dependent so that such an extension is not wanted. */
      
      cfun->machine->sibcall_fails = 1;
    }

  /* Test if all registers needed by the ABI are actually available.  If the
     user has fixed a GPR needed to pass an argument, an (implicit) function
     call will clobber that fixed register.  See PR45099 for an example.  */
  
  if (cum->regno >= 8
      && cum->nregs >= 0)
    {
      int regno;

      for (regno = cum->regno; regno < cum->regno + bytes; regno++)
        if (fixed_regs[regno])
          warning (0, "fixed register %s used to pass parameter to function",
                   reg_names[regno]);
    }
      
  if (cum->nregs <= 0)
    {
      cum->nregs = 0;
      cum->regno = FIRST_CUM_REG;
    }
}

/* Implement `TARGET_FUNCTION_OK_FOR_SIBCALL' */
/* Decide whether we can make a sibling call to a function.  DECL is the
   declaration of the function being targeted by the call and EXP is the
   CALL_EXPR representing the call. */

static bool
avr_function_ok_for_sibcall (tree decl_callee, tree exp_callee)
{
  tree fntype_callee;

  /* Tail-calling must fail if callee-saved regs are used to pass
     function args.  We must not tail-call when `epilogue_restores'
     is used.  Unfortunately, we cannot tell at this point if that
     actually will happen or not, and we cannot step back from
     tail-calling. Thus, we inhibit tail-calling with -mcall-prologues. */
  
  if (cfun->machine->sibcall_fails
      || TARGET_CALL_PROLOGUES)
    {
      return false;
    }
  
  fntype_callee = TREE_TYPE (CALL_EXPR_FN (exp_callee));

  if (decl_callee)
    {
      decl_callee = TREE_TYPE (decl_callee);
    }
  else
    {
      decl_callee = fntype_callee;
      
      while (FUNCTION_TYPE != TREE_CODE (decl_callee)
             && METHOD_TYPE != TREE_CODE (decl_callee))
        {
          decl_callee = TREE_TYPE (decl_callee);
        }
    }

  /* Ensure that caller and callee have compatible epilogues */
  
  if (interrupt_function_p (current_function_decl)
      || signal_function_p (current_function_decl)
      || avr_naked_function_p (decl_callee)
      || avr_naked_function_p (current_function_decl)
      /* FIXME: For OS_task and OS_main, we are over-conservative.
         This is due to missing documentation of these attributes
         and what they actually should do and should not do. */
      || (avr_OS_task_function_p (decl_callee)
          != avr_OS_task_function_p (current_function_decl))
      || (avr_OS_main_function_p (decl_callee)
          != avr_OS_main_function_p (current_function_decl)))
    {
      return false;
    }
 
  return true;
}

/***********************************************************************
  Functions for outputting various mov's for a various modes
************************************************************************/

/* Return true if a value of mode MODE is read from flash by
   __load_* function from libgcc.  */

bool
avr_load_libgcc_p (rtx op)
{
  enum machine_mode mode = GET_MODE (op);
  int n_bytes = GET_MODE_SIZE (mode);
        
  return (n_bytes > 2
          && !AVR_HAVE_LPMX
          && avr_mem_flash_p (op));
}

/* Return true if a value of mode MODE is read by __xload_* function.  */

bool
avr_xload_libgcc_p (enum machine_mode mode)
{
  int n_bytes = GET_MODE_SIZE (mode);
  
  return (n_bytes > 1
          || avr_current_arch->n_segments > 1);
}


/* Find an unused d-register to be used as scratch in INSN.
   EXCLUDE is either NULL_RTX or some register. In the case where EXCLUDE
   is a register, skip all possible return values that overlap EXCLUDE.
   The policy for the returned register is similar to that of
   `reg_unused_after', i.e. the returned register may overlap the SET_DEST
   of INSN.

   Return a QImode d-register or NULL_RTX if nothing found.  */

static rtx
avr_find_unused_d_reg (rtx insn, rtx exclude)
{
  int regno;
  bool isr_p = (interrupt_function_p (current_function_decl)
                || signal_function_p (current_function_decl));

  for (regno = 16; regno < 32; regno++)
    {
      rtx reg = all_regs_rtx[regno];
      
      if ((exclude
           && reg_overlap_mentioned_p (exclude, reg))
          || fixed_regs[regno])
        {
          continue;
        }

      /* Try non-live register */

      if (!df_regs_ever_live_p (regno)
          && (TREE_THIS_VOLATILE (current_function_decl)
              || cfun->machine->is_OS_task
              || cfun->machine->is_OS_main
              || (!isr_p && call_used_regs[regno])))
        {
          return reg;
        }

      /* Any live register can be used if it is unused after.
         Prologue/epilogue will care for it as needed.  */
      
      if (df_regs_ever_live_p (regno)
          && reg_unused_after (insn, reg))
        {
          return reg;
        }
    }

  return NULL_RTX;
}


/* Helper function for the next function in the case where only restricted
   version of LPM instruction is available.  */

static const char*
avr_out_lpm_no_lpmx (rtx insn, rtx *xop, int *plen)
{
  rtx dest = xop[0];
  rtx addr = xop[1];
  int n_bytes = GET_MODE_SIZE (GET_MODE (dest));
  int regno_dest;

  regno_dest = REGNO (dest);

  /* The implicit target register of LPM.  */
  xop[3] = lpm_reg_rtx;

  switch (GET_CODE (addr))
    {
    default:
      gcc_unreachable();

    case REG:

      gcc_assert (REG_Z == REGNO (addr));

      switch (n_bytes)
        {
        default:
          gcc_unreachable();

        case 1:
          avr_asm_len ("%4lpm", xop, plen, 1);

          if (regno_dest != LPM_REGNO)
            avr_asm_len ("mov %0,%3", xop, plen, 1);

          return "";

        case 2:
          if (REGNO (dest) == REG_Z)
            return avr_asm_len ("%4lpm"      CR_TAB
                                "push %3"    CR_TAB
                                "adiw %2,1"  CR_TAB
                                "%4lpm"      CR_TAB
                                "mov %B0,%3" CR_TAB
                                "pop %A0", xop, plen, 6);
          
          avr_asm_len ("%4lpm"      CR_TAB
                       "mov %A0,%3" CR_TAB
                       "adiw %2,1"  CR_TAB
                       "%4lpm"      CR_TAB
                       "mov %B0,%3", xop, plen, 5);
                
          if (!reg_unused_after (insn, addr))
            avr_asm_len ("sbiw %2,1", xop, plen, 1);
          
          break; /* 2 */
        }
      
      break; /* REG */

    case POST_INC:

      gcc_assert (REG_Z == REGNO (XEXP (addr, 0))
                  && n_bytes <= 4);

      if (regno_dest == LPM_REGNO)
        avr_asm_len ("%4lpm"      CR_TAB
                     "adiw %2,1", xop, plen, 2);
      else
        avr_asm_len ("%4lpm"      CR_TAB
                     "mov %A0,%3" CR_TAB
                     "adiw %2,1", xop, plen, 3);

      if (n_bytes >= 2)
        avr_asm_len ("%4lpm"      CR_TAB
                     "mov %B0,%3" CR_TAB
                     "adiw %2,1", xop, plen, 3);

      if (n_bytes >= 3)
        avr_asm_len ("%4lpm"      CR_TAB
                     "mov %C0,%3" CR_TAB
                     "adiw %2,1", xop, plen, 3);

      if (n_bytes >= 4)
        avr_asm_len ("%4lpm"      CR_TAB
                     "mov %D0,%3" CR_TAB
                     "adiw %2,1", xop, plen, 3);

      break; /* POST_INC */
      
    } /* switch CODE (addr) */
      
  return "";
}


/* If PLEN == NULL: Ouput instructions to load a value from a memory location
   OP[1] in AS1 to register OP[0].
   If PLEN != 0 set *PLEN to the length in words of the instruction sequence.
   Return "".  */

static const char*
avr_out_lpm (rtx insn, rtx *op, int *plen)
{
  rtx xop[6];
  rtx dest = op[0];
  rtx src = SET_SRC (single_set (insn));
  rtx addr;
  int n_bytes = GET_MODE_SIZE (GET_MODE (dest));
  int regno_dest;
  int segment;
  RTX_CODE code;
  addr_space_t as = MEM_ADDR_SPACE (src);

  if (plen)
    *plen = 0;
  
  if (MEM_P (dest))
    {
      warning (0, "writing to address space %qs not supported",
               avr_addrspace[MEM_ADDR_SPACE (dest)].name);
      
      return "";
    }

  addr = XEXP (src, 0);
  code = GET_CODE (addr);

  gcc_assert (REG_P (dest));
  gcc_assert (REG == code || POST_INC == code);

  xop[0] = dest;
  xop[1] = addr;
  xop[2] = lpm_addr_reg_rtx;
  xop[4] = xstring_empty;
  xop[5] = tmp_reg_rtx;

  regno_dest = REGNO (dest);

  /* Cut down segment number to a number the device actually supports.
     We do this late to preserve the address space's name for diagnostics.  */

  segment = avr_addrspace[as].segment % avr_current_arch->n_segments;

  /* Set RAMPZ as needed.  */

  if (segment)
    {
      xop[4] = GEN_INT (segment);
      
      if (xop[3] = avr_find_unused_d_reg (insn, lpm_addr_reg_rtx),
          xop[3])
        {
          avr_asm_len ("ldi %3,%4" CR_TAB
                       "out __RAMPZ__,%3", xop, plen, 2);
        }
      else if (segment == 1)
        {
          avr_asm_len ("clr %5" CR_TAB
                       "inc %5" CR_TAB
                       "out __RAMPZ__,%5", xop, plen, 3);
        }
      else
        {
          avr_asm_len ("mov %5,%2"         CR_TAB
                       "ldi %2,%4"         CR_TAB
                       "out __RAMPZ__,%2"  CR_TAB
                       "mov %2,%5", xop, plen, 4);
        }
      
      xop[4] = xstring_e;

      if (!AVR_HAVE_ELPMX)
        return avr_out_lpm_no_lpmx (insn, xop, plen);
    }
  else if (!AVR_HAVE_LPMX)
    {
      return avr_out_lpm_no_lpmx (insn, xop, plen);
    }

  /* We have [E]LPMX: Output reading from Flash the comfortable way.  */

  switch (GET_CODE (addr))
    {
    default:
      gcc_unreachable();

    case REG:

      gcc_assert (REG_Z == REGNO (addr));

      switch (n_bytes)
        {
        default:
          gcc_unreachable();

        case 1:
          return avr_asm_len ("%4lpm %0,%a2", xop, plen, 1);

        case 2:
          if (REGNO (dest) == REG_Z)
            return avr_asm_len ("%4lpm %5,%a2+" CR_TAB
                                "%4lpm %B0,%a2" CR_TAB
                                "mov %A0,%5", xop, plen, 3);
          else
            {
              avr_asm_len ("%4lpm %A0,%a2+" CR_TAB
                           "%4lpm %B0,%a2", xop, plen, 2);
                
              if (!reg_unused_after (insn, addr))
                avr_asm_len ("sbiw %2,1", xop, plen, 1);
            }
          
          break; /* 2 */

        case 3:

          avr_asm_len ("%4lpm %A0,%a2+" CR_TAB
                       "%4lpm %B0,%a2+" CR_TAB
                       "%4lpm %C0,%a2", xop, plen, 3);
                
          if (!reg_unused_after (insn, addr))
            avr_asm_len ("sbiw %2,2", xop, plen, 1);

          break; /* 3 */
      
        case 4:

          avr_asm_len ("%4lpm %A0,%a2+" CR_TAB
                       "%4lpm %B0,%a2+", xop, plen, 2);
          
          if (REGNO (dest) == REG_Z - 2)
            return avr_asm_len ("%4lpm %5,%a2+" CR_TAB
                                "%4lpm %C0,%a2"          CR_TAB
                                "mov %D0,%5", xop, plen, 3);
          else
            {
              avr_asm_len ("%4lpm %C0,%a2+" CR_TAB
                           "%4lpm %D0,%a2", xop, plen, 2);
                
              if (!reg_unused_after (insn, addr))
                avr_asm_len ("sbiw %2,3", xop, plen, 1);
            }

          break; /* 4 */
        } /* n_bytes */
      
      break; /* REG */

    case POST_INC:

      gcc_assert (REG_Z == REGNO (XEXP (addr, 0))
                  && n_bytes <= 4);

      avr_asm_len                    ("%4lpm %A0,%a2+", xop, plen, 1);
      if (n_bytes >= 2)  avr_asm_len ("%4lpm %B0,%a2+", xop, plen, 1);
      if (n_bytes >= 3)  avr_asm_len ("%4lpm %C0,%a2+", xop, plen, 1);
      if (n_bytes >= 4)  avr_asm_len ("%4lpm %D0,%a2+", xop, plen, 1);

      break; /* POST_INC */

    } /* switch CODE (addr) */
      
  return "";
}


/* Worker function for xload_8 insn.  */

const char*
avr_out_xload (rtx insn ATTRIBUTE_UNUSED, rtx *op, int *plen)
{
  rtx xop[4];

  xop[0] = op[0];
  xop[1] = op[1];
  xop[2] = lpm_addr_reg_rtx;
  xop[3] = AVR_HAVE_LPMX ? op[0] : lpm_reg_rtx;

  if (plen)
    *plen = 0;

  avr_asm_len ("ld %3,%a2" CR_TAB
               "sbrs %1,7", xop, plen, 2);

  avr_asm_len (AVR_HAVE_LPMX ? "lpm %3,%a2" : "lpm", xop, plen, 1);

  if (REGNO (xop[0]) != REGNO (xop[3]))
    avr_asm_len ("mov %0,%3", xop, plen, 1);
  
  return "";
}


const char *
output_movqi (rtx insn, rtx operands[], int *l)
{
  int dummy;
  rtx dest = operands[0];
  rtx src = operands[1];
  int *real_l = l;
  
  if (avr_mem_flash_p (src)
      || avr_mem_flash_p (dest))
    {
      return avr_out_lpm (insn, operands, real_l);
    }

  if (!l)
    l = &dummy;

  *l = 1;
  
  if (register_operand (dest, QImode))
    {
      if (register_operand (src, QImode)) /* mov r,r */
        {
          if (test_hard_reg_class (STACK_REG, dest))
            return "out %0,%1";
          else if (test_hard_reg_class (STACK_REG, src))
            return "in %0,%1";
          
          return "mov %0,%1";
        }
      else if (CONSTANT_P (src))
        {
          output_reload_in_const (operands, NULL_RTX, real_l, false);
          return "";
        }
      else if (GET_CODE (src) == MEM)
        return out_movqi_r_mr (insn, operands, real_l); /* mov r,m */
    }
  else if (GET_CODE (dest) == MEM)
    {
      rtx xop[2];

      xop[0] = dest;
      xop[1] = src == const0_rtx ? zero_reg_rtx : src;

      return out_movqi_mr_r (insn, xop, real_l);
    }
  return "";
}


const char *
output_movhi (rtx insn, rtx xop[], int *plen)
{
  rtx dest = xop[0];
  rtx src = xop[1];

  gcc_assert (GET_MODE_SIZE (GET_MODE (dest)) == 2);
  
  if (avr_mem_flash_p (src)
      || avr_mem_flash_p (dest))
    {
      return avr_out_lpm (insn, xop, plen);
    }

  if (REG_P (dest))
    {
      if (REG_P (src)) /* mov r,r */
        {
          if (test_hard_reg_class (STACK_REG, dest))
            {
              if (AVR_HAVE_8BIT_SP)
                return avr_asm_len ("out __SP_L__,%A1", xop, plen, -1);

              if (AVR_XMEGA)
                return avr_asm_len ("out __SP_L__,%A1" CR_TAB
                                    "out __SP_H__,%B1", xop, plen, -2);
              
              /* Use simple load of SP if no interrupts are  used.  */
              
              return TARGET_NO_INTERRUPTS
                ? avr_asm_len ("out __SP_H__,%B1" CR_TAB
                               "out __SP_L__,%A1", xop, plen, -2)

                : avr_asm_len ("in __tmp_reg__,__SREG__"  CR_TAB
                               "cli"                      CR_TAB
                               "out __SP_H__,%B1"         CR_TAB
                               "out __SREG__,__tmp_reg__" CR_TAB
                               "out __SP_L__,%A1", xop, plen, -5);
            }
          else if (test_hard_reg_class (STACK_REG, src))
            {
              return AVR_HAVE_8BIT_SP
                ? avr_asm_len ("in %A0,__SP_L__" CR_TAB
                               "clr %B0", xop, plen, -2)
                
                : avr_asm_len ("in %A0,__SP_L__" CR_TAB
                               "in %B0,__SP_H__", xop, plen, -2);
            }

          return AVR_HAVE_MOVW
            ? avr_asm_len ("movw %0,%1", xop, plen, -1)

            : avr_asm_len ("mov %A0,%A1" CR_TAB
                           "mov %B0,%B1", xop, plen, -2);
        } /* REG_P (src) */
      else if (CONSTANT_P (src))
        {
          return output_reload_inhi (xop, NULL, plen);
        }
      else if (MEM_P (src))
        {
          return out_movhi_r_mr (insn, xop, plen); /* mov r,m */
        }
    }
  else if (MEM_P (dest))
    {
      rtx xop[2];

      xop[0] = dest;
      xop[1] = src == const0_rtx ? zero_reg_rtx : src;

      return out_movhi_mr_r (insn, xop, plen);
    }
  
  fatal_insn ("invalid insn:", insn);
  
  return "";
}

static const char*
out_movqi_r_mr (rtx insn, rtx op[], int *plen)
{
  rtx dest = op[0];
  rtx src = op[1];
  rtx x = XEXP (src, 0);
  
  if (CONSTANT_ADDRESS_P (x))
    {
      return optimize > 0 && io_address_operand (x, QImode)
        ? avr_asm_len ("in %0,%i1", op, plen, -1)
        : avr_asm_len ("lds %0,%m1", op, plen, -2);
    }
  else if (GET_CODE (x) == PLUS
           && REG_P (XEXP (x, 0))
           && CONST_INT_P (XEXP (x, 1)))
    {
      /* memory access by reg+disp */

      int disp = INTVAL (XEXP (x, 1));
      
      if (disp - GET_MODE_SIZE (GET_MODE (src)) >= 63)
        {
          if (REGNO (XEXP (x, 0)) != REG_Y)
            fatal_insn ("incorrect insn:",insn);

          if (disp <= 63 + MAX_LD_OFFSET (GET_MODE (src)))
            return avr_asm_len ("adiw r28,%o1-63" CR_TAB
                                "ldd %0,Y+63"     CR_TAB
                                "sbiw r28,%o1-63", op, plen, -3);

          return avr_asm_len ("subi r28,lo8(-%o1)" CR_TAB
                              "sbci r29,hi8(-%o1)" CR_TAB
                              "ld %0,Y"            CR_TAB
                              "subi r28,lo8(%o1)"  CR_TAB
                              "sbci r29,hi8(%o1)", op, plen, -5);
        }
      else if (REGNO (XEXP (x, 0)) == REG_X)
        {
          /* This is a paranoid case LEGITIMIZE_RELOAD_ADDRESS must exclude
             it but I have this situation with extremal optimizing options.  */
          
          avr_asm_len ("adiw r26,%o1" CR_TAB
                       "ld %0,X", op, plen, -2);
          
          if (!reg_overlap_mentioned_p (dest, XEXP (x,0))
              && !reg_unused_after (insn, XEXP (x,0)))
            {
              avr_asm_len ("sbiw r26,%o1", op, plen, 1);
            }

          return "";
        }

      return avr_asm_len ("ldd %0,%1", op, plen, -1);
    }
  
  return avr_asm_len ("ld %0,%1", op, plen, -1);
}

static const char*
out_movhi_r_mr (rtx insn, rtx op[], int *plen)
{
  rtx dest = op[0];
  rtx src = op[1];
  rtx base = XEXP (src, 0);
  int reg_dest = true_regnum (dest);
  int reg_base = true_regnum (base);
  /* "volatile" forces reading low byte first, even if less efficient,
     for correct operation with 16-bit I/O registers.  */
  int mem_volatile_p = MEM_VOLATILE_P (src);

  if (reg_base > 0)
    {
      if (reg_dest == reg_base)         /* R = (R) */
        return avr_asm_len ("ld __tmp_reg__,%1+" CR_TAB
                            "ld %B0,%1"          CR_TAB
                            "mov %A0,__tmp_reg__", op, plen, -3);

      if (reg_base != REG_X)
        return avr_asm_len ("ld %A0,%1" CR_TAB
                            "ldd %B0,%1+1", op, plen, -2);
      
      avr_asm_len ("ld %A0,X+" CR_TAB
                   "ld %B0,X", op, plen, -2);
          
      if (!reg_unused_after (insn, base))
        avr_asm_len ("sbiw r26,1", op, plen, 1);

      return "";
    }
  else if (GET_CODE (base) == PLUS) /* (R + i) */
    {
      int disp = INTVAL (XEXP (base, 1));
      int reg_base = true_regnum (XEXP (base, 0));
      
      if (disp > MAX_LD_OFFSET (GET_MODE (src)))
        {
          if (REGNO (XEXP (base, 0)) != REG_Y)
            fatal_insn ("incorrect insn:",insn);
          
          return disp <= 63 + MAX_LD_OFFSET (GET_MODE (src))
            ? avr_asm_len ("adiw r28,%o1-62" CR_TAB
                           "ldd %A0,Y+62"    CR_TAB
                           "ldd %B0,Y+63"    CR_TAB
                           "sbiw r28,%o1-62", op, plen, -4)

            : avr_asm_len ("subi r28,lo8(-%o1)" CR_TAB
                           "sbci r29,hi8(-%o1)" CR_TAB
                           "ld %A0,Y"           CR_TAB
                           "ldd %B0,Y+1"        CR_TAB
                           "subi r28,lo8(%o1)"  CR_TAB
                           "sbci r29,hi8(%o1)", op, plen, -6);
        }

      /* This is a paranoid case. LEGITIMIZE_RELOAD_ADDRESS must exclude
         it but I have this situation with extremal
         optimization options.  */

      if (reg_base == REG_X)
        return reg_base == reg_dest
          ? avr_asm_len ("adiw r26,%o1"      CR_TAB
                         "ld __tmp_reg__,X+" CR_TAB
                         "ld %B0,X"          CR_TAB
                         "mov %A0,__tmp_reg__", op, plen, -4)

          : avr_asm_len ("adiw r26,%o1" CR_TAB
                         "ld %A0,X+"    CR_TAB
                         "ld %B0,X"     CR_TAB
                         "sbiw r26,%o1+1", op, plen, -4);

      return reg_base == reg_dest
        ? avr_asm_len ("ldd __tmp_reg__,%A1" CR_TAB
                       "ldd %B0,%B1"         CR_TAB
                       "mov %A0,__tmp_reg__", op, plen, -3)

        : avr_asm_len ("ldd %A0,%A1" CR_TAB
                       "ldd %B0,%B1", op, plen, -2);
    }
  else if (GET_CODE (base) == PRE_DEC) /* (--R) */
    {
      if (reg_overlap_mentioned_p (dest, XEXP (base, 0)))
        fatal_insn ("incorrect insn:", insn);

      if (!mem_volatile_p)
        return avr_asm_len ("ld %B0,%1" CR_TAB
                            "ld %A0,%1", op, plen, -2);
      
      return REGNO (XEXP (base, 0)) == REG_X
        ? avr_asm_len ("sbiw r26,2"  CR_TAB
                       "ld %A0,X+"   CR_TAB
                       "ld %B0,X"    CR_TAB
                       "sbiw r26,1", op, plen, -4)
        
        : avr_asm_len ("sbiw %r1,2"  CR_TAB
                       "ld %A0,%p1"  CR_TAB
                       "ldd %B0,%p1+1", op, plen, -3);
    }
  else if (GET_CODE (base) == POST_INC) /* (R++) */
    {
      if (reg_overlap_mentioned_p (dest, XEXP (base, 0)))
        fatal_insn ("incorrect insn:", insn);

      return avr_asm_len ("ld %A0,%1"  CR_TAB
                          "ld %B0,%1", op, plen, -2);
    }
  else if (CONSTANT_ADDRESS_P (base))
    {
      return optimize > 0 && io_address_operand (base, HImode)
        ? avr_asm_len ("in %A0,%i1" CR_TAB
                       "in %B0,%i1+1", op, plen, -2)

        : avr_asm_len ("lds %A0,%m1" CR_TAB
                       "lds %B0,%m1+1", op, plen, -4);
    }
  
  fatal_insn ("unknown move insn:",insn);
  return "";
}

static const char*
out_movsi_r_mr (rtx insn, rtx op[], int *l)
{
  rtx dest = op[0];
  rtx src = op[1];
  rtx base = XEXP (src, 0);
  int reg_dest = true_regnum (dest);
  int reg_base = true_regnum (base);
  int tmp;

  if (!l)
    l = &tmp;
  
  if (reg_base > 0)
    {
      if (reg_base == REG_X)        /* (R26) */
        {
          if (reg_dest == REG_X)
            /* "ld r26,-X" is undefined */
            return *l=7, ("adiw r26,3"        CR_TAB
                          "ld r29,X"          CR_TAB
                          "ld r28,-X"         CR_TAB
                          "ld __tmp_reg__,-X" CR_TAB
                          "sbiw r26,1"        CR_TAB
                          "ld r26,X"          CR_TAB
                          "mov r27,__tmp_reg__");
          else if (reg_dest == REG_X - 2)
            return *l=5, ("ld %A0,X+"          CR_TAB
                          "ld %B0,X+"          CR_TAB
                          "ld __tmp_reg__,X+"  CR_TAB
                          "ld %D0,X"           CR_TAB
                          "mov %C0,__tmp_reg__");
          else if (reg_unused_after (insn, base))
            return  *l=4, ("ld %A0,X+"  CR_TAB
                           "ld %B0,X+" CR_TAB
                           "ld %C0,X+" CR_TAB
                           "ld %D0,X");
          else
            return  *l=5, ("ld %A0,X+"  CR_TAB
                           "ld %B0,X+" CR_TAB
                           "ld %C0,X+" CR_TAB
                           "ld %D0,X"  CR_TAB
                           "sbiw r26,3");
        }
      else
        {
          if (reg_dest == reg_base)
            return *l=5, ("ldd %D0,%1+3" CR_TAB
                          "ldd %C0,%1+2" CR_TAB
                          "ldd __tmp_reg__,%1+1"  CR_TAB
                          "ld %A0,%1"  CR_TAB
                          "mov %B0,__tmp_reg__");
          else if (reg_base == reg_dest + 2)
            return *l=5, ("ld %A0,%1"             CR_TAB
                          "ldd %B0,%1+1"          CR_TAB
                          "ldd __tmp_reg__,%1+2"  CR_TAB
                          "ldd %D0,%1+3"          CR_TAB
                          "mov %C0,__tmp_reg__");
          else
            return *l=4, ("ld %A0,%1"    CR_TAB
                          "ldd %B0,%1+1" CR_TAB
                          "ldd %C0,%1+2" CR_TAB
                          "ldd %D0,%1+3");
        }
    }
  else if (GET_CODE (base) == PLUS) /* (R + i) */
    {
      int disp = INTVAL (XEXP (base, 1));
      
      if (disp > MAX_LD_OFFSET (GET_MODE (src)))
        {
          if (REGNO (XEXP (base, 0)) != REG_Y)
            fatal_insn ("incorrect insn:",insn);

          if (disp <= 63 + MAX_LD_OFFSET (GET_MODE (src)))
            return *l = 6, ("adiw r28,%o1-60" CR_TAB
                            "ldd %A0,Y+60"    CR_TAB
                            "ldd %B0,Y+61"    CR_TAB
                            "ldd %C0,Y+62"    CR_TAB
                            "ldd %D0,Y+63"    CR_TAB
                            "sbiw r28,%o1-60");

          return *l = 8, ("subi r28,lo8(-%o1)" CR_TAB
                          "sbci r29,hi8(-%o1)" CR_TAB
                          "ld %A0,Y"           CR_TAB
                          "ldd %B0,Y+1"        CR_TAB
                          "ldd %C0,Y+2"        CR_TAB
                          "ldd %D0,Y+3"        CR_TAB
                          "subi r28,lo8(%o1)"  CR_TAB
                          "sbci r29,hi8(%o1)");
        }

      reg_base = true_regnum (XEXP (base, 0));
      if (reg_base == REG_X)
        {
          /* R = (X + d) */
          if (reg_dest == REG_X)
            {
              *l = 7;
              /* "ld r26,-X" is undefined */
              return ("adiw r26,%o1+3"    CR_TAB
                      "ld r29,X"          CR_TAB
                      "ld r28,-X"         CR_TAB
                      "ld __tmp_reg__,-X" CR_TAB
                      "sbiw r26,1"        CR_TAB
                      "ld r26,X"          CR_TAB
                      "mov r27,__tmp_reg__");
            }
          *l = 6;
          if (reg_dest == REG_X - 2)
            return ("adiw r26,%o1"      CR_TAB
                    "ld r24,X+"         CR_TAB
                    "ld r25,X+"         CR_TAB
                    "ld __tmp_reg__,X+" CR_TAB
                    "ld r27,X"          CR_TAB
                    "mov r26,__tmp_reg__");

          return ("adiw r26,%o1" CR_TAB
                  "ld %A0,X+"    CR_TAB
                  "ld %B0,X+"    CR_TAB
                  "ld %C0,X+"    CR_TAB
                  "ld %D0,X"     CR_TAB
                  "sbiw r26,%o1+3");
        }
      if (reg_dest == reg_base)
        return *l=5, ("ldd %D0,%D1"          CR_TAB
                      "ldd %C0,%C1"          CR_TAB
                      "ldd __tmp_reg__,%B1"  CR_TAB
                      "ldd %A0,%A1"          CR_TAB
                      "mov %B0,__tmp_reg__");
      else if (reg_dest == reg_base - 2)
        return *l=5, ("ldd %A0,%A1"          CR_TAB
                      "ldd %B0,%B1"          CR_TAB
                      "ldd __tmp_reg__,%C1"  CR_TAB
                      "ldd %D0,%D1"          CR_TAB
                      "mov %C0,__tmp_reg__");
      return *l=4, ("ldd %A0,%A1" CR_TAB
                    "ldd %B0,%B1" CR_TAB
                    "ldd %C0,%C1" CR_TAB
                    "ldd %D0,%D1");
    }
  else if (GET_CODE (base) == PRE_DEC) /* (--R) */
    return *l=4, ("ld %D0,%1" CR_TAB
                  "ld %C0,%1" CR_TAB
                  "ld %B0,%1" CR_TAB
                  "ld %A0,%1");
  else if (GET_CODE (base) == POST_INC) /* (R++) */
    return *l=4, ("ld %A0,%1" CR_TAB
                  "ld %B0,%1" CR_TAB
                  "ld %C0,%1" CR_TAB
                  "ld %D0,%1");
  else if (CONSTANT_ADDRESS_P (base))
    return *l=8, ("lds %A0,%m1"   CR_TAB
                  "lds %B0,%m1+1" CR_TAB
                  "lds %C0,%m1+2" CR_TAB
                  "lds %D0,%m1+3");
    
  fatal_insn ("unknown move insn:",insn);
  return "";
}

static const char*
out_movsi_mr_r (rtx insn, rtx op[], int *l)
{
  rtx dest = op[0];
  rtx src = op[1];
  rtx base = XEXP (dest, 0);
  int reg_base = true_regnum (base);
  int reg_src = true_regnum (src);
  int tmp;
  
  if (!l)
    l = &tmp;
  
  if (CONSTANT_ADDRESS_P (base))
    return *l=8,("sts %m0,%A1" CR_TAB
                 "sts %m0+1,%B1" CR_TAB
                 "sts %m0+2,%C1" CR_TAB
                 "sts %m0+3,%D1");
  if (reg_base > 0)                 /* (r) */
    {
      if (reg_base == REG_X)                /* (R26) */
        {
          if (reg_src == REG_X)
            {
              /* "st X+,r26" is undefined */
              if (reg_unused_after (insn, base))
                return *l=6, ("mov __tmp_reg__,r27" CR_TAB
                              "st X,r26"            CR_TAB
                              "adiw r26,1"          CR_TAB
                              "st X+,__tmp_reg__"   CR_TAB
                              "st X+,r28"           CR_TAB
                              "st X,r29");
              else
                return *l=7, ("mov __tmp_reg__,r27" CR_TAB
                              "st X,r26"            CR_TAB
                              "adiw r26,1"          CR_TAB
                              "st X+,__tmp_reg__"   CR_TAB
                              "st X+,r28"           CR_TAB
                              "st X,r29"            CR_TAB
                              "sbiw r26,3");
            }
          else if (reg_base == reg_src + 2)
            {
              if (reg_unused_after (insn, base))
                return *l=7, ("mov __zero_reg__,%C1" CR_TAB
                              "mov __tmp_reg__,%D1"  CR_TAB
                              "st %0+,%A1"           CR_TAB
                              "st %0+,%B1"           CR_TAB
                              "st %0+,__zero_reg__"  CR_TAB
                              "st %0,__tmp_reg__"    CR_TAB
                              "clr __zero_reg__");
              else
                return *l=8, ("mov __zero_reg__,%C1" CR_TAB
                              "mov __tmp_reg__,%D1"  CR_TAB
                              "st %0+,%A1"           CR_TAB
                              "st %0+,%B1"           CR_TAB
                              "st %0+,__zero_reg__"  CR_TAB
                              "st %0,__tmp_reg__"    CR_TAB
                              "clr __zero_reg__"     CR_TAB
                              "sbiw r26,3");
            }
          return *l=5, ("st %0+,%A1" CR_TAB
                        "st %0+,%B1" CR_TAB
                        "st %0+,%C1" CR_TAB
                        "st %0,%D1"  CR_TAB
                        "sbiw r26,3");
        }
      else
        return *l=4, ("st %0,%A1"    CR_TAB
                      "std %0+1,%B1" CR_TAB
                      "std %0+2,%C1" CR_TAB
                      "std %0+3,%D1");
    }
  else if (GET_CODE (base) == PLUS) /* (R + i) */
    {
      int disp = INTVAL (XEXP (base, 1));
      reg_base = REGNO (XEXP (base, 0));
      if (disp > MAX_LD_OFFSET (GET_MODE (dest)))
        {
          if (reg_base != REG_Y)
            fatal_insn ("incorrect insn:",insn);

          if (disp <= 63 + MAX_LD_OFFSET (GET_MODE (dest)))
            return *l = 6, ("adiw r28,%o0-60" CR_TAB
                            "std Y+60,%A1"    CR_TAB
                            "std Y+61,%B1"    CR_TAB
                            "std Y+62,%C1"    CR_TAB
                            "std Y+63,%D1"    CR_TAB
                            "sbiw r28,%o0-60");

          return *l = 8, ("subi r28,lo8(-%o0)" CR_TAB
                          "sbci r29,hi8(-%o0)" CR_TAB
                          "st Y,%A1"           CR_TAB
                          "std Y+1,%B1"        CR_TAB
                          "std Y+2,%C1"        CR_TAB
                          "std Y+3,%D1"        CR_TAB
                          "subi r28,lo8(%o0)"  CR_TAB
                          "sbci r29,hi8(%o0)");
        }
      if (reg_base == REG_X)
        {
          /* (X + d) = R */
          if (reg_src == REG_X)
            {
              *l = 9;
              return ("mov __tmp_reg__,r26"  CR_TAB
                      "mov __zero_reg__,r27" CR_TAB
                      "adiw r26,%o0"         CR_TAB
                      "st X+,__tmp_reg__"    CR_TAB
                      "st X+,__zero_reg__"   CR_TAB
                      "st X+,r28"            CR_TAB
                      "st X,r29"             CR_TAB
                      "clr __zero_reg__"     CR_TAB
                      "sbiw r26,%o0+3");
            }
          else if (reg_src == REG_X - 2)
            {
              *l = 9;
              return ("mov __tmp_reg__,r26"  CR_TAB
                      "mov __zero_reg__,r27" CR_TAB
                      "adiw r26,%o0"         CR_TAB
                      "st X+,r24"            CR_TAB
                      "st X+,r25"            CR_TAB
                      "st X+,__tmp_reg__"    CR_TAB
                      "st X,__zero_reg__"    CR_TAB
                      "clr __zero_reg__"     CR_TAB
                      "sbiw r26,%o0+3");
            }
          *l = 6;
          return ("adiw r26,%o0" CR_TAB
                  "st X+,%A1"    CR_TAB
                  "st X+,%B1"    CR_TAB
                  "st X+,%C1"    CR_TAB
                  "st X,%D1"     CR_TAB
                  "sbiw r26,%o0+3");
        }
      return *l=4, ("std %A0,%A1" CR_TAB
                    "std %B0,%B1" CR_TAB
                    "std %C0,%C1" CR_TAB
                    "std %D0,%D1");
    }
  else if (GET_CODE (base) == PRE_DEC) /* (--R) */
    return *l=4, ("st %0,%D1" CR_TAB
                  "st %0,%C1" CR_TAB
                  "st %0,%B1" CR_TAB
                  "st %0,%A1");
  else if (GET_CODE (base) == POST_INC) /* (R++) */
    return *l=4, ("st %0,%A1" CR_TAB
                  "st %0,%B1" CR_TAB
                  "st %0,%C1" CR_TAB
                  "st %0,%D1");
  fatal_insn ("unknown move insn:",insn);
  return "";
}

const char *
output_movsisf (rtx insn, rtx operands[], int *l)
{
  int dummy;
  rtx dest = operands[0];
  rtx src = operands[1];
  int *real_l = l;
  
  if (avr_mem_flash_p (src)
      || avr_mem_flash_p (dest))
    {
      return avr_out_lpm (insn, operands, real_l);
    }

  if (!l)
    l = &dummy;
  
  if (register_operand (dest, VOIDmode))
    {
      if (register_operand (src, VOIDmode)) /* mov r,r */
        {
          if (true_regnum (dest) > true_regnum (src))
            {
              if (AVR_HAVE_MOVW)
                {
                  *l = 2;
                  return ("movw %C0,%C1" CR_TAB
                          "movw %A0,%A1");
                }
              *l = 4;
              return ("mov %D0,%D1" CR_TAB
                      "mov %C0,%C1" CR_TAB
                      "mov %B0,%B1" CR_TAB
                      "mov %A0,%A1");
            }
          else
            {
              if (AVR_HAVE_MOVW)
                {
                  *l = 2;
                  return ("movw %A0,%A1" CR_TAB
                          "movw %C0,%C1");
                }
              *l = 4;
              return ("mov %A0,%A1" CR_TAB
                      "mov %B0,%B1" CR_TAB
                      "mov %C0,%C1" CR_TAB
                      "mov %D0,%D1");
            }
        }
      else if (CONSTANT_P (src))
        {
          return output_reload_insisf (operands, NULL_RTX, real_l);
        }
      else if (GET_CODE (src) == MEM)
        return out_movsi_r_mr (insn, operands, real_l); /* mov r,m */
    }
  else if (GET_CODE (dest) == MEM)
    {
      const char *templ;

      if (src == CONST0_RTX (GET_MODE (dest)))
          operands[1] = zero_reg_rtx;

      templ = out_movsi_mr_r (insn, operands, real_l);

      if (!real_l)
        output_asm_insn (templ, operands);

      operands[1] = src;
      return "";
    }
  fatal_insn ("invalid insn:", insn);
  return "";
}


/* Handle loads of 24-bit types from memory to register.  */

static const char*
avr_out_load_psi (rtx insn, rtx *op, int *plen)
{
  rtx dest = op[0];
  rtx src = op[1];
  rtx base = XEXP (src, 0);
  int reg_dest = true_regnum (dest);
  int reg_base = true_regnum (base);
  
  if (reg_base > 0)
    {
      if (reg_base == REG_X)        /* (R26) */
        {
          if (reg_dest == REG_X)
            /* "ld r26,-X" is undefined */
            return avr_asm_len ("adiw r26,2"        CR_TAB
                                "ld r28,X"          CR_TAB
                                "ld __tmp_reg__,-X" CR_TAB
                                "sbiw r26,1"        CR_TAB
                                "ld r26,X"          CR_TAB
                                "mov r27,__tmp_reg__", op, plen, -6);
          else
            {
              avr_asm_len ("ld %A0,X+" CR_TAB
                           "ld %B0,X+" CR_TAB
                           "ld %C0,X", op, plen, -3);

              if (reg_dest != REG_X - 2
                  && !reg_unused_after (insn, base))
                {
                  avr_asm_len ("sbiw r26,2", op, plen, 1);
                }

              return "";
            }
        }
      else /* reg_base != REG_X */
        {
          if (reg_dest == reg_base)
            return avr_asm_len ("ldd %C0,%1+2"          CR_TAB
                                "ldd __tmp_reg__,%1+1"  CR_TAB
                                "ld  %A0,%1"            CR_TAB
                                "mov %B0,__tmp_reg__", op, plen, -4);
          else
            return avr_asm_len ("ld  %A0,%1"    CR_TAB
                                "ldd %B0,%1+1"  CR_TAB
                                "ldd %C0,%1+2", op, plen, -3);
        }
    }
  else if (GET_CODE (base) == PLUS) /* (R + i) */
    {
      int disp = INTVAL (XEXP (base, 1));
      
      if (disp > MAX_LD_OFFSET (GET_MODE (src)))
        {
          if (REGNO (XEXP (base, 0)) != REG_Y)
            fatal_insn ("incorrect insn:",insn);

          if (disp <= 63 + MAX_LD_OFFSET (GET_MODE (src)))
            return avr_asm_len ("adiw r28,%o1-61" CR_TAB
                                "ldd %A0,Y+61"    CR_TAB
                                "ldd %B0,Y+62"    CR_TAB
                                "ldd %C0,Y+63"    CR_TAB
                                "sbiw r28,%o1-61", op, plen, -5);

          return avr_asm_len ("subi r28,lo8(-%o1)" CR_TAB
                              "sbci r29,hi8(-%o1)" CR_TAB
                              "ld  %A0,Y"           CR_TAB
                              "ldd %B0,Y+1"        CR_TAB
                              "ldd %C0,Y+2"        CR_TAB
                              "subi r28,lo8(%o1)"  CR_TAB
                              "sbci r29,hi8(%o1)", op, plen, -7);
        }

      reg_base = true_regnum (XEXP (base, 0));
      if (reg_base == REG_X)
        {
          /* R = (X + d) */
          if (reg_dest == REG_X)
            {
              /* "ld r26,-X" is undefined */
              return avr_asm_len ("adiw r26,%o1+2"     CR_TAB
                                  "ld  r28,X"          CR_TAB
                                  "ld  __tmp_reg__,-X" CR_TAB
                                  "sbiw r26,1"         CR_TAB
                                  "ld  r26,X"          CR_TAB
                                  "mov r27,__tmp_reg__", op, plen, -6);
            }
          
            avr_asm_len ("adiw r26,%o1"      CR_TAB
                         "ld r24,X+"         CR_TAB
                         "ld r25,X+"         CR_TAB
                         "ld r26,X", op, plen, -4);

            if (reg_dest != REG_X - 2)
              avr_asm_len ("sbiw r26,%o1+2", op, plen, 1);

            return "";
        }
      
      if (reg_dest == reg_base)
        return avr_asm_len ("ldd %C0,%C1" CR_TAB
                            "ldd __tmp_reg__,%B1"  CR_TAB
                            "ldd %A0,%A1" CR_TAB
                            "mov %B0,__tmp_reg__", op, plen, -4);

        return avr_asm_len ("ldd %A0,%A1" CR_TAB
                            "ldd %B0,%B1" CR_TAB
                            "ldd %C0,%C1", op, plen, -3);
    }
  else if (GET_CODE (base) == PRE_DEC) /* (--R) */
    return avr_asm_len ("ld %C0,%1" CR_TAB
                        "ld %B0,%1" CR_TAB
                        "ld %A0,%1", op, plen, -3);
  else if (GET_CODE (base) == POST_INC) /* (R++) */
    return avr_asm_len ("ld %A0,%1" CR_TAB
                        "ld %B0,%1" CR_TAB
                        "ld %C0,%1", op, plen, -3);

  else if (CONSTANT_ADDRESS_P (base))
    return avr_asm_len ("lds %A0,%m1" CR_TAB
                        "lds %B0,%m1+1" CR_TAB
                        "lds %C0,%m1+2", op, plen , -6);
  
  fatal_insn ("unknown move insn:",insn);
  return "";
}

/* Handle store of 24-bit type from register or zero to memory.  */

static const char*
avr_out_store_psi (rtx insn, rtx *op, int *plen)
{
  rtx dest = op[0];
  rtx src = op[1];
  rtx base = XEXP (dest, 0);
  int reg_base = true_regnum (base);
  
  if (CONSTANT_ADDRESS_P (base))
    return avr_asm_len ("sts %m0,%A1"   CR_TAB
                        "sts %m0+1,%B1" CR_TAB
                        "sts %m0+2,%C1", op, plen, -6);
  
  if (reg_base > 0)                 /* (r) */
    {
      if (reg_base == REG_X)        /* (R26) */
        {
          gcc_assert (!reg_overlap_mentioned_p (base, src));
          
          avr_asm_len ("st %0+,%A1"  CR_TAB
                       "st %0+,%B1" CR_TAB
                       "st %0,%C1", op, plen, -3);

          if (!reg_unused_after (insn, base))
            avr_asm_len ("sbiw r26,2", op, plen, 1);

          return "";
        }
      else
        return avr_asm_len ("st %0,%A1"    CR_TAB
                            "std %0+1,%B1" CR_TAB
                            "std %0+2,%C1", op, plen, -3);
    }
  else if (GET_CODE (base) == PLUS) /* (R + i) */
    {
      int disp = INTVAL (XEXP (base, 1));
      reg_base = REGNO (XEXP (base, 0));

      if (disp > MAX_LD_OFFSET (GET_MODE (dest)))
        {
          if (reg_base != REG_Y)
            fatal_insn ("incorrect insn:",insn);

          if (disp <= 63 + MAX_LD_OFFSET (GET_MODE (dest)))
            return avr_asm_len ("adiw r28,%o0-61" CR_TAB
                                "std Y+61,%A1"    CR_TAB
                                "std Y+62,%B1"    CR_TAB
                                "std Y+63,%C1"    CR_TAB
                                "sbiw r28,%o0-60", op, plen, -5);

          return avr_asm_len ("subi r28,lo8(-%o0)" CR_TAB
                              "sbci r29,hi8(-%o0)" CR_TAB
                              "st Y,%A1"           CR_TAB
                              "std Y+1,%B1"        CR_TAB
                              "std Y+2,%C1"        CR_TAB
                              "subi r28,lo8(%o0)"  CR_TAB
                              "sbci r29,hi8(%o0)", op, plen, -7);
        }
      if (reg_base == REG_X)
        {
          /* (X + d) = R */
          gcc_assert (!reg_overlap_mentioned_p (XEXP (base, 0), src));
          
          avr_asm_len ("adiw r26,%o0" CR_TAB
                       "st X+,%A1"    CR_TAB
                       "st X+,%B1"    CR_TAB
                       "st X,%C1", op, plen, -4);

          if (!reg_unused_after (insn, XEXP (base, 0)))
            avr_asm_len ("sbiw r26,%o0+2", op, plen, 1);

          return "";
        }
      
      return avr_asm_len ("std %A0,%A1" CR_TAB
                          "std %B0,%B1" CR_TAB
                          "std %C0,%C1", op, plen, -3);
    }
  else if (GET_CODE (base) == PRE_DEC) /* (--R) */
    return avr_asm_len ("st %0,%C1" CR_TAB
                        "st %0,%B1" CR_TAB
                        "st %0,%A1", op, plen, -3);
  else if (GET_CODE (base) == POST_INC) /* (R++) */
    return avr_asm_len ("st %0,%A1" CR_TAB
                        "st %0,%B1" CR_TAB
                        "st %0,%C1", op, plen, -3);

  fatal_insn ("unknown move insn:",insn);
  return "";
}


/* Move around 24-bit stuff.  */

const char *
avr_out_movpsi (rtx insn, rtx *op, int *plen)
{
  rtx dest = op[0];
  rtx src = op[1];
  
  if (avr_mem_flash_p (src)
      || avr_mem_flash_p (dest))
    {
      return avr_out_lpm (insn, op, plen);
    }
  
  if (register_operand (dest, VOIDmode))
    {
      if (register_operand (src, VOIDmode)) /* mov r,r */
        {
          if (true_regnum (dest) > true_regnum (src))
            {
              avr_asm_len ("mov %C0,%C1", op, plen, -1);

              if (AVR_HAVE_MOVW)
                return avr_asm_len ("movw %A0,%A1", op, plen, 1);
              else
                return avr_asm_len ("mov %B0,%B1"  CR_TAB
                                    "mov %A0,%A1", op, plen, 2);
            }
          else
            {
              if (AVR_HAVE_MOVW)
                avr_asm_len ("movw %A0,%A1", op, plen, -1);
              else
                avr_asm_len ("mov %A0,%A1"  CR_TAB
                             "mov %B0,%B1", op, plen, -2);
              
              return avr_asm_len ("mov %C0,%C1", op, plen, 1);
            }
        }
      else if (CONSTANT_P (src))
        {
          return avr_out_reload_inpsi (op, NULL_RTX, plen);
        }
      else if (MEM_P (src))
        return avr_out_load_psi (insn, op, plen); /* mov r,m */
    }
  else if (MEM_P (dest))
    {
      rtx xop[2];

      xop[0] = dest;
      xop[1] = src == CONST0_RTX (GET_MODE (dest)) ? zero_reg_rtx : src;
      
      return avr_out_store_psi (insn, xop, plen);
    }
    
  fatal_insn ("invalid insn:", insn);
  return "";
}


static const char*
out_movqi_mr_r (rtx insn, rtx op[], int *plen)
{
  rtx dest = op[0];
  rtx src = op[1];
  rtx x = XEXP (dest, 0);
  
  if (CONSTANT_ADDRESS_P (x))
    {
      return optimize > 0 && io_address_operand (x, QImode)
        ? avr_asm_len ("out %i0,%1", op, plen, -1)
        : avr_asm_len ("sts %m0,%1", op, plen, -2);
    }
  else if (GET_CODE (x) == PLUS
           && REG_P (XEXP (x, 0))
           && CONST_INT_P (XEXP (x, 1)))
    {
      /* memory access by reg+disp */

      int disp = INTVAL (XEXP (x, 1));

      if (disp - GET_MODE_SIZE (GET_MODE (dest)) >= 63)
        {
          if (REGNO (XEXP (x, 0)) != REG_Y)
            fatal_insn ("incorrect insn:",insn);

          if (disp <= 63 + MAX_LD_OFFSET (GET_MODE (dest)))
            return avr_asm_len ("adiw r28,%o0-63" CR_TAB
                                "std Y+63,%1"     CR_TAB
                                "sbiw r28,%o0-63", op, plen, -3);

          return avr_asm_len ("subi r28,lo8(-%o0)" CR_TAB
                              "sbci r29,hi8(-%o0)" CR_TAB
                              "st Y,%1"            CR_TAB
                              "subi r28,lo8(%o0)"  CR_TAB
                              "sbci r29,hi8(%o0)", op, plen, -5);
        }
      else if (REGNO (XEXP (x,0)) == REG_X)
        {
          if (reg_overlap_mentioned_p (src, XEXP (x, 0)))
            {
              avr_asm_len ("mov __tmp_reg__,%1" CR_TAB
                           "adiw r26,%o0"       CR_TAB
                           "st X,__tmp_reg__", op, plen, -3);
            }
          else
            {
              avr_asm_len ("adiw r26,%o0" CR_TAB
                           "st X,%1", op, plen, -2);
            }
          
          if (!reg_unused_after (insn, XEXP (x,0)))
            avr_asm_len ("sbiw r26,%o0", op, plen, 1);

          return "";
        }
      
      return avr_asm_len ("std %0,%1", op, plen, -1);
    }
  
  return avr_asm_len ("st %0,%1", op, plen, -1);
}


/* Helper for the next function for XMEGA.  It does the same
   but with low byte first.  */

static const char*
avr_out_movhi_mr_r_xmega (rtx insn, rtx op[], int *plen)
{
  rtx dest = op[0];
  rtx src = op[1];
  rtx base = XEXP (dest, 0);
  int reg_base = true_regnum (base);
  int reg_src = true_regnum (src);

  /* "volatile" forces writing low byte first, even if less efficient,
     for correct operation with 16-bit I/O registers like SP.  */
  int mem_volatile_p = MEM_VOLATILE_P (dest);

  if (CONSTANT_ADDRESS_P (base))
    return optimize > 0 && io_address_operand (base, HImode)
      ? avr_asm_len ("out %i0,%A1" CR_TAB
                     "out %i0+1,%B1", op, plen, -2)

      : avr_asm_len ("sts %m0,%A1" CR_TAB
                     "sts %m0+1,%B1", op, plen, -4);
  
  if (reg_base > 0)
    {
      if (reg_base != REG_X)
        return avr_asm_len ("st %0,%A1" CR_TAB
                            "std %0+1,%B1", op, plen, -2);
      
      if (reg_src == REG_X)
        /* "st X+,r26" and "st -X,r26" are undefined.  */
        avr_asm_len ("mov __tmp_reg__,r27" CR_TAB
                     "st X,r26"            CR_TAB
                     "adiw r26,1"          CR_TAB
                     "st X,__tmp_reg__", op, plen, -4);
      else
        avr_asm_len ("st X+,%A1" CR_TAB
                     "st X,%B1", op, plen, -2);

      return reg_unused_after (insn, base)
        ? ""
        : avr_asm_len ("sbiw r26,1", op, plen, 1);
    }
  else if (GET_CODE (base) == PLUS)
    {
      int disp = INTVAL (XEXP (base, 1));
      reg_base = REGNO (XEXP (base, 0));
      if (disp > MAX_LD_OFFSET (GET_MODE (dest)))
        {
          if (reg_base != REG_Y)
            fatal_insn ("incorrect insn:",insn);
          
          return disp <= 63 + MAX_LD_OFFSET (GET_MODE (dest))
            ? avr_asm_len ("adiw r28,%o0-62" CR_TAB
                           "std Y+62,%A1"    CR_TAB
                           "std Y+63,%B1"    CR_TAB
                           "sbiw r28,%o0-62", op, plen, -4)

            : avr_asm_len ("subi r28,lo8(-%o0)" CR_TAB
                           "sbci r29,hi8(-%o0)" CR_TAB
                           "st Y,%A1"           CR_TAB
                           "std Y+1,%B1"        CR_TAB
                           "subi r28,lo8(%o0)"  CR_TAB
                           "sbci r29,hi8(%o0)", op, plen, -6);
        }
      
      if (reg_base != REG_X)
        return avr_asm_len ("std %A0,%A1" CR_TAB
                            "std %B0,%B1", op, plen, -2);
      /* (X + d) = R */
      return reg_src == REG_X
        ? avr_asm_len ("mov __tmp_reg__,r26"  CR_TAB
                       "mov __zero_reg__,r27" CR_TAB
                       "adiw r26,%o0"         CR_TAB
                       "st X+,__tmp_reg__"    CR_TAB
                       "st X,__zero_reg__"    CR_TAB
                       "clr __zero_reg__"     CR_TAB
                       "sbiw r26,%o0+1", op, plen, -7)

        : avr_asm_len ("adiw r26,%o0" CR_TAB
                       "st X+,%A1"    CR_TAB
                       "st X,%B1"     CR_TAB
                       "sbiw r26,%o0+1", op, plen, -4);
    }
  else if (GET_CODE (base) == PRE_DEC) /* (--R) */
    {
      if (!mem_volatile_p)
        return avr_asm_len ("st %0,%B1" CR_TAB
                            "st %0,%A1", op, plen, -2);

      return REGNO (XEXP (base, 0)) == REG_X
        ? avr_asm_len ("sbiw r26,2"  CR_TAB
                       "st X+,%A1"   CR_TAB
                       "st X,%B1"    CR_TAB
                       "sbiw r26,1", op, plen, -4)

        : avr_asm_len ("sbiw %r0,2"  CR_TAB
                       "st %p0,%A1"  CR_TAB
                       "std %p0+1,%B1", op, plen, -3);
    }
  else if (GET_CODE (base) == POST_INC) /* (R++) */
    {
      return avr_asm_len ("st %0,%A1"  CR_TAB
                          "st %0,%B1", op, plen, -2);
      
    }
  fatal_insn ("unknown move insn:",insn);
  return "";
}


static const char*
out_movhi_mr_r (rtx insn, rtx op[], int *plen)
{
  rtx dest = op[0];
  rtx src = op[1];
  rtx base = XEXP (dest, 0);
  int reg_base = true_regnum (base);
  int reg_src = true_regnum (src);
  int mem_volatile_p;

  /* "volatile" forces writing high-byte first (no-xmega) resp.
     low-byte first (xmega) even if less efficient, for correct
     operation with 16-bit I/O registers like.  */

  if (AVR_XMEGA)
    return avr_out_movhi_mr_r_xmega (insn, op, plen);

  mem_volatile_p = MEM_VOLATILE_P (dest);

  if (CONSTANT_ADDRESS_P (base))
    return optimize > 0 && io_address_operand (base, HImode)
      ? avr_asm_len ("out %i0+1,%B1" CR_TAB
                     "out %i0,%A1", op, plen, -2)

      : avr_asm_len ("sts %m0+1,%B1" CR_TAB
                     "sts %m0,%A1", op, plen, -4);
  
  if (reg_base > 0)
    {
      if (reg_base != REG_X)
        return avr_asm_len ("std %0+1,%B1" CR_TAB
                            "st %0,%A1", op, plen, -2);
      
      if (reg_src == REG_X)
        /* "st X+,r26" and "st -X,r26" are undefined.  */
        return !mem_volatile_p && reg_unused_after (insn, src)
          ? avr_asm_len ("mov __tmp_reg__,r27" CR_TAB
                         "st X,r26"            CR_TAB
                         "adiw r26,1"          CR_TAB
                         "st X,__tmp_reg__", op, plen, -4)

          : avr_asm_len ("mov __tmp_reg__,r27" CR_TAB
                         "adiw r26,1"          CR_TAB
                         "st X,__tmp_reg__"    CR_TAB
                         "sbiw r26,1"          CR_TAB
                         "st X,r26", op, plen, -5);
      
      return !mem_volatile_p && reg_unused_after (insn, base)
        ? avr_asm_len ("st X+,%A1" CR_TAB
                       "st X,%B1", op, plen, -2)
        : avr_asm_len ("adiw r26,1" CR_TAB
                       "st X,%B1"   CR_TAB
                       "st -X,%A1", op, plen, -3);
    }
  else if (GET_CODE (base) == PLUS)
    {
      int disp = INTVAL (XEXP (base, 1));
      reg_base = REGNO (XEXP (base, 0));
      if (disp > MAX_LD_OFFSET (GET_MODE (dest)))
        {
          if (reg_base != REG_Y)
            fatal_insn ("incorrect insn:",insn);
          
          return disp <= 63 + MAX_LD_OFFSET (GET_MODE (dest))
            ? avr_asm_len ("adiw r28,%o0-62" CR_TAB
                           "std Y+63,%B1"    CR_TAB
                           "std Y+62,%A1"    CR_TAB
                           "sbiw r28,%o0-62", op, plen, -4)

            : avr_asm_len ("subi r28,lo8(-%o0)" CR_TAB
                           "sbci r29,hi8(-%o0)" CR_TAB
                           "std Y+1,%B1"        CR_TAB
                           "st Y,%A1"           CR_TAB
                           "subi r28,lo8(%o0)"  CR_TAB
                           "sbci r29,hi8(%o0)", op, plen, -6);
        }
      
      if (reg_base != REG_X)
        return avr_asm_len ("std %B0,%B1" CR_TAB
                            "std %A0,%A1", op, plen, -2);
      /* (X + d) = R */
      return reg_src == REG_X
        ? avr_asm_len ("mov __tmp_reg__,r26"  CR_TAB
                       "mov __zero_reg__,r27" CR_TAB
                       "adiw r26,%o0+1"       CR_TAB
                       "st X,__zero_reg__"    CR_TAB
                       "st -X,__tmp_reg__"    CR_TAB
                       "clr __zero_reg__"     CR_TAB
                       "sbiw r26,%o0", op, plen, -7)

        : avr_asm_len ("adiw r26,%o0+1" CR_TAB
                       "st X,%B1"       CR_TAB
                       "st -X,%A1"      CR_TAB
                       "sbiw r26,%o0", op, plen, -4);
    }
  else if (GET_CODE (base) == PRE_DEC) /* (--R) */
    {
      return avr_asm_len ("st %0,%B1" CR_TAB
                          "st %0,%A1", op, plen, -2);
    }
  else if (GET_CODE (base) == POST_INC) /* (R++) */
    {
      if (!mem_volatile_p)
        return avr_asm_len ("st %0,%A1"  CR_TAB
                            "st %0,%B1", op, plen, -2);
      
      return REGNO (XEXP (base, 0)) == REG_X
        ? avr_asm_len ("adiw r26,1"  CR_TAB
                       "st X,%B1"    CR_TAB
                       "st -X,%A1"   CR_TAB
                       "adiw r26,2", op, plen, -4)

        : avr_asm_len ("std %p0+1,%B1" CR_TAB
                       "st %p0,%A1"    CR_TAB
                       "adiw %r0,2", op, plen, -3);
    }
  fatal_insn ("unknown move insn:",insn);
  return "";
}

/* Return 1 if frame pointer for current function required.  */

static bool
avr_frame_pointer_required_p (void)
{
  return (cfun->calls_alloca
          || cfun->calls_setjmp
          || cfun->has_nonlocal_label
          || crtl->args.info.nregs == 0
          || get_frame_size () > 0);
}

/* Returns the condition of compare insn INSN, or UNKNOWN.  */

static RTX_CODE
compare_condition (rtx insn)
{
  rtx next = next_real_insn (insn);

  if (next && JUMP_P (next))
    {
      rtx pat = PATTERN (next);
      rtx src = SET_SRC (pat);
      
      if (IF_THEN_ELSE == GET_CODE (src))
        return GET_CODE (XEXP (src, 0));
    }
  
  return UNKNOWN;
}


/* Returns true iff INSN is a tst insn that only tests the sign.  */

static bool
compare_sign_p (rtx insn)
{
  RTX_CODE cond = compare_condition (insn);
  return (cond == GE || cond == LT);
}


/* Returns true iff the next insn is a JUMP_INSN with a condition
   that needs to be swapped (GT, GTU, LE, LEU).  */

static bool
compare_diff_p (rtx insn)
{
  RTX_CODE cond = compare_condition (insn);
  return (cond == GT || cond == GTU || cond == LE || cond == LEU) ? cond : 0;
}

/* Returns true iff INSN is a compare insn with the EQ or NE condition.  */

static bool
compare_eq_p (rtx insn)
{
  RTX_CODE cond = compare_condition (insn);
  return (cond == EQ || cond == NE);
}


/* Output compare instruction

      compare (XOP[0], XOP[1])

   for an HI/SI register XOP[0] and an integer XOP[1].  Return "".
   XOP[2] is an 8-bit scratch register as needed.

   PLEN == NULL:  Output instructions.
   PLEN != NULL:  Set *PLEN to the length (in words) of the sequence.
                  Don't output anything.  */

const char*
avr_out_compare (rtx insn, rtx *xop, int *plen)
{
  /* Register to compare and value to compare against. */
  rtx xreg = xop[0];
  rtx xval = xop[1];
  
  /* MODE of the comparison.  */
  enum machine_mode mode = GET_MODE (xreg);

  /* Number of bytes to operate on.  */
  int i, n_bytes = GET_MODE_SIZE (mode);

  /* Value (0..0xff) held in clobber register xop[2] or -1 if unknown.  */
  int clobber_val = -1;

  gcc_assert (REG_P (xreg));
  gcc_assert ((CONST_INT_P (xval) && n_bytes <= 4)
              || (const_double_operand (xval, VOIDmode) && n_bytes == 8));
  
  if (plen)
    *plen = 0;

  /* Comparisons == +/-1 and != +/-1 can be done similar to camparing
     against 0 by ORing the bytes.  This is one instruction shorter.
     Notice that DImode comparisons are always against reg:DI 18
     and therefore don't use this.  */

  if (!test_hard_reg_class (LD_REGS, xreg)
      && compare_eq_p (insn)
      && reg_unused_after (insn, xreg))
    {
      if (xval == const1_rtx)
        {
          avr_asm_len ("dec %A0" CR_TAB
                       "or %A0,%B0", xop, plen, 2);
          
          if (n_bytes >= 3)
            avr_asm_len ("or %A0,%C0", xop, plen, 1);

          if (n_bytes >= 4)
            avr_asm_len ("or %A0,%D0", xop, plen, 1);

          return "";
        }
      else if (xval == constm1_rtx)
        {
          if (n_bytes >= 4)
            avr_asm_len ("and %A0,%D0", xop, plen, 1);
          
          if (n_bytes >= 3)
            avr_asm_len ("and %A0,%C0", xop, plen, 1);
          
          return avr_asm_len ("and %A0,%B0" CR_TAB
                              "com %A0", xop, plen, 2);
        }
    }

  for (i = 0; i < n_bytes; i++)
    {
      /* We compare byte-wise.  */
      rtx reg8 = simplify_gen_subreg (QImode, xreg, mode, i);
      rtx xval8 = simplify_gen_subreg (QImode, xval, mode, i);

      /* 8-bit value to compare with this byte.  */
      unsigned int val8 = UINTVAL (xval8) & GET_MODE_MASK (QImode);

      /* Registers R16..R31 can operate with immediate.  */
      bool ld_reg_p = test_hard_reg_class (LD_REGS, reg8);

      xop[0] = reg8;
      xop[1] = gen_int_mode (val8, QImode);

      /* Word registers >= R24 can use SBIW/ADIW with 0..63.  */

      if (i == 0
          && test_hard_reg_class (ADDW_REGS, reg8))
        {
          int val16 = trunc_int_for_mode (INTVAL (xval), HImode);
          
          if (IN_RANGE (val16, 0, 63)
              && (val8 == 0
                  || reg_unused_after (insn, xreg)))
            {
              avr_asm_len ("sbiw %0,%1", xop, plen, 1);
              i++;
              continue;
            }

          if (n_bytes == 2
              && IN_RANGE (val16, -63, -1)
              && compare_eq_p (insn)
              && reg_unused_after (insn, xreg))
            {
              return avr_asm_len ("adiw %0,%n1", xop, plen, 1);
            }
        }

      /* Comparing against 0 is easy.  */
      
      if (val8 == 0)
        {
          avr_asm_len (i == 0
                       ? "cp %0,__zero_reg__"
                       : "cpc %0,__zero_reg__", xop, plen, 1);
          continue;
        }

      /* Upper registers can compare and subtract-with-carry immediates.
         Notice that compare instructions do the same as respective subtract
         instruction; the only difference is that comparisons don't write
         the result back to the target register.  */

      if (ld_reg_p)
        {
          if (i == 0)
            {
              avr_asm_len ("cpi %0,%1", xop, plen, 1);
              continue;
            }
          else if (reg_unused_after (insn, xreg))
            {
              avr_asm_len ("sbci %0,%1", xop, plen, 1);
              continue;
            }
        }

      /* Must load the value into the scratch register.  */

      gcc_assert (REG_P (xop[2]));
              
      if (clobber_val != (int) val8)
        avr_asm_len ("ldi %2,%1", xop, plen, 1);
      clobber_val = (int) val8;
              
      avr_asm_len (i == 0
                   ? "cp %0,%2"
                   : "cpc %0,%2", xop, plen, 1);
    }

  return "";
}


/* Prepare operands of compare_const_di2 to be used with avr_out_compare.  */

const char*
avr_out_compare64 (rtx insn, rtx *op, int *plen)
{
  rtx xop[3];

  xop[0] = gen_rtx_REG (DImode, 18);
  xop[1] = op[0];
  xop[2] = op[1];

  return avr_out_compare (insn, xop, plen);
}

/* Output test instruction for HImode.  */

const char*
avr_out_tsthi (rtx insn, rtx *op, int *plen)
{
  if (compare_sign_p (insn))
    {
      avr_asm_len ("tst %B0", op, plen, -1);
    }
  else if (reg_unused_after (insn, op[0])
           && compare_eq_p (insn))
    {
      /* Faster than sbiw if we can clobber the operand.  */
      avr_asm_len ("or %A0,%B0", op, plen, -1);
    }
  else
    {
      avr_out_compare (insn, op, plen);
    }

  return "";
}


/* Output test instruction for PSImode.  */

const char*
avr_out_tstpsi (rtx insn, rtx *op, int *plen)
{
  if (compare_sign_p (insn))
    {
      avr_asm_len ("tst %C0", op, plen, -1);
    }
  else if (reg_unused_after (insn, op[0])
           && compare_eq_p (insn))
    {
      /* Faster than sbiw if we can clobber the operand.  */
      avr_asm_len ("or %A0,%B0" CR_TAB
                   "or %A0,%C0", op, plen, -2);
    }
  else
    {
      avr_out_compare (insn, op, plen);
    }

  return "";
}


/* Output test instruction for SImode.  */

const char*
avr_out_tstsi (rtx insn, rtx *op, int *plen)
{
  if (compare_sign_p (insn))
    {
      avr_asm_len ("tst %D0", op, plen, -1);
    }
  else if (reg_unused_after (insn, op[0])
           && compare_eq_p (insn))
    {
      /* Faster than sbiw if we can clobber the operand.  */
      avr_asm_len ("or %A0,%B0" CR_TAB
                   "or %A0,%C0" CR_TAB
                   "or %A0,%D0", op, plen, -3);
    }
  else
    {
      avr_out_compare (insn, op, plen);
    }

  return "";
}


/* Generate asm equivalent for various shifts.  This only handles cases
   that are not already carefully hand-optimized in ?sh??i3_out.

   OPERANDS[0] resp. %0 in TEMPL is the operand to be shifted.
   OPERANDS[2] is the shift count as CONST_INT, MEM or REG.
   OPERANDS[3] is a QImode scratch register from LD regs if
               available and SCRATCH, otherwise (no scratch available)

   TEMPL is an assembler template that shifts by one position.
   T_LEN is the length of this template.  */

void
out_shift_with_cnt (const char *templ, rtx insn, rtx operands[],
                    int *plen, int t_len)
{
  bool second_label = true;
  bool saved_in_tmp = false;
  bool use_zero_reg = false;
  rtx op[5];

  op[0] = operands[0];
  op[1] = operands[1];
  op[2] = operands[2];
  op[3] = operands[3];

  if (plen)
    *plen = 0;

  if (CONST_INT_P (operands[2]))
    {
      bool scratch = (GET_CODE (PATTERN (insn)) == PARALLEL
                      && REG_P (operands[3]));
      int count = INTVAL (operands[2]);
      int max_len = 10;  /* If larger than this, always use a loop.  */

      if (count <= 0)
          return;

      if (count < 8 && !scratch)
        use_zero_reg = true;

      if (optimize_size)
        max_len = t_len + (scratch ? 3 : (use_zero_reg ? 4 : 5));

      if (t_len * count <= max_len)
        {
          /* Output shifts inline with no loop - faster.  */
          
          while (count-- > 0)
            avr_asm_len (templ, op, plen, t_len);

          return;
        }

      if (scratch)
        {
          avr_asm_len ("ldi %3,%2", op, plen, 1);
        }
      else if (use_zero_reg)
        {
          /* Hack to save one word: use __zero_reg__ as loop counter.
             Set one bit, then shift in a loop until it is 0 again.  */

          op[3] = zero_reg_rtx;

          avr_asm_len ("set" CR_TAB
                       "bld %3,%2-1", op, plen, 2);
        }
      else
        {
          /* No scratch register available, use one from LD_REGS (saved in
             __tmp_reg__) that doesn't overlap with registers to shift.  */

          op[3] = all_regs_rtx[((REGNO (op[0]) - 1) & 15) + 16];
          op[4] = tmp_reg_rtx;
          saved_in_tmp = true;

          avr_asm_len ("mov %4,%3" CR_TAB
                       "ldi %3,%2", op, plen, 2);
        }

      second_label = false;
    }
  else if (MEM_P (op[2]))
    {
      rtx op_mov[2];
      
      op_mov[0] = op[3] = tmp_reg_rtx;
      op_mov[1] = op[2];

      out_movqi_r_mr (insn, op_mov, plen);
    }
  else if (register_operand (op[2], QImode))
    {
      op[3] = op[2];
      
      if (!reg_unused_after (insn, op[2])
          || reg_overlap_mentioned_p (op[0], op[2]))
        {
          op[3] = tmp_reg_rtx;
          avr_asm_len ("mov %3,%2", op, plen, 1);
        }
    }
  else
    fatal_insn ("bad shift insn:", insn);

  if (second_label)
      avr_asm_len ("rjmp 2f", op, plen, 1);

  avr_asm_len ("1:", op, plen, 0);
  avr_asm_len (templ, op, plen, t_len);

  if (second_label)
    avr_asm_len ("2:", op, plen, 0);

  avr_asm_len (use_zero_reg ? "lsr %3" : "dec %3", op, plen, 1);
  avr_asm_len (second_label ? "brpl 1b" : "brne 1b", op, plen, 1);

  if (saved_in_tmp)
    avr_asm_len ("mov %3,%4", op, plen, 1);
}


/* 8bit shift left ((char)x << i)   */

const char *
ashlqi3_out (rtx insn, rtx operands[], int *len)
{
  if (GET_CODE (operands[2]) == CONST_INT)
    {
      int k;

      if (!len)
        len = &k;

      switch (INTVAL (operands[2]))
        {
        default:
          if (INTVAL (operands[2]) < 8)
            break;

          *len = 1;
          return "clr %0";
          
        case 1:
          *len = 1;
          return "lsl %0";
          
        case 2:
          *len = 2;
          return ("lsl %0" CR_TAB
                  "lsl %0");

        case 3:
          *len = 3;
          return ("lsl %0" CR_TAB
                  "lsl %0" CR_TAB
                  "lsl %0");

        case 4:
          if (test_hard_reg_class (LD_REGS, operands[0]))
            {
              *len = 2;
              return ("swap %0" CR_TAB
                      "andi %0,0xf0");
            }
          *len = 4;
          return ("lsl %0" CR_TAB
                  "lsl %0" CR_TAB
                  "lsl %0" CR_TAB
                  "lsl %0");

        case 5:
          if (test_hard_reg_class (LD_REGS, operands[0]))
            {
              *len = 3;
              return ("swap %0" CR_TAB
                      "lsl %0"  CR_TAB
                      "andi %0,0xe0");
            }
          *len = 5;
          return ("lsl %0" CR_TAB
                  "lsl %0" CR_TAB
                  "lsl %0" CR_TAB
                  "lsl %0" CR_TAB
                  "lsl %0");

        case 6:
          if (test_hard_reg_class (LD_REGS, operands[0]))
            {
              *len = 4;
              return ("swap %0" CR_TAB
                      "lsl %0"  CR_TAB
                      "lsl %0"  CR_TAB
                      "andi %0,0xc0");
            }
          *len = 6;
          return ("lsl %0" CR_TAB
                  "lsl %0" CR_TAB
                  "lsl %0" CR_TAB
                  "lsl %0" CR_TAB
                  "lsl %0" CR_TAB
                  "lsl %0");

        case 7:
          *len = 3;
          return ("ror %0" CR_TAB
                  "clr %0" CR_TAB
                  "ror %0");
        }
    }
  else if (CONSTANT_P (operands[2]))
    fatal_insn ("internal compiler error.  Incorrect shift:", insn);

  out_shift_with_cnt ("lsl %0",
                      insn, operands, len, 1);
  return "";
}


/* 16bit shift left ((short)x << i)   */

const char *
ashlhi3_out (rtx insn, rtx operands[], int *len)
{
  if (GET_CODE (operands[2]) == CONST_INT)
    {
      int scratch = (GET_CODE (PATTERN (insn)) == PARALLEL);
      int ldi_ok = test_hard_reg_class (LD_REGS, operands[0]);
      int k;
      int *t = len;

      if (!len)
        len = &k;
      
      switch (INTVAL (operands[2]))
        {
        default:
          if (INTVAL (operands[2]) < 16)
            break;

          *len = 2;
          return ("clr %B0" CR_TAB
                  "clr %A0");

        case 4:
          if (optimize_size && scratch)
            break;  /* 5 */
          if (ldi_ok)
            {
              *len = 6;
              return ("swap %A0"      CR_TAB
                      "swap %B0"      CR_TAB
                      "andi %B0,0xf0" CR_TAB
                      "eor %B0,%A0"   CR_TAB
                      "andi %A0,0xf0" CR_TAB
                      "eor %B0,%A0");
            }
          if (scratch)
            {
              *len = 7;
              return ("swap %A0"    CR_TAB
                      "swap %B0"    CR_TAB
                      "ldi %3,0xf0" CR_TAB
                      "and %B0,%3"      CR_TAB
                      "eor %B0,%A0" CR_TAB
                      "and %A0,%3"      CR_TAB
                      "eor %B0,%A0");
            }
          break;  /* optimize_size ? 6 : 8 */

        case 5:
          if (optimize_size)
            break;  /* scratch ? 5 : 6 */
          if (ldi_ok)
            {
              *len = 8;
              return ("lsl %A0"       CR_TAB
                      "rol %B0"       CR_TAB
                      "swap %A0"      CR_TAB
                      "swap %B0"      CR_TAB
                      "andi %B0,0xf0" CR_TAB
                      "eor %B0,%A0"   CR_TAB
                      "andi %A0,0xf0" CR_TAB
                      "eor %B0,%A0");
            }
          if (scratch)
            {
              *len = 9;
              return ("lsl %A0"     CR_TAB
                      "rol %B0"     CR_TAB
                      "swap %A0"    CR_TAB
                      "swap %B0"    CR_TAB
                      "ldi %3,0xf0" CR_TAB
                      "and %B0,%3"      CR_TAB
                      "eor %B0,%A0" CR_TAB
                      "and %A0,%3"      CR_TAB
                      "eor %B0,%A0");
            }
          break;  /* 10 */

        case 6:
          if (optimize_size)
            break;  /* scratch ? 5 : 6 */
          *len = 9;
          return ("clr __tmp_reg__" CR_TAB
                  "lsr %B0"         CR_TAB
                  "ror %A0"         CR_TAB
                  "ror __tmp_reg__" CR_TAB
                  "lsr %B0"         CR_TAB
                  "ror %A0"         CR_TAB
                  "ror __tmp_reg__" CR_TAB
                  "mov %B0,%A0"     CR_TAB
                  "mov %A0,__tmp_reg__");

        case 7:
          *len = 5;
          return ("lsr %B0"     CR_TAB
                  "mov %B0,%A0" CR_TAB
                  "clr %A0"     CR_TAB
                  "ror %B0"     CR_TAB
                  "ror %A0");

        case 8:
          return *len = 2, ("mov %B0,%A1" CR_TAB
                            "clr %A0");

        case 9:
          *len = 3;
          return ("mov %B0,%A0" CR_TAB
                  "clr %A0"     CR_TAB
                  "lsl %B0");

        case 10:
          *len = 4;
          return ("mov %B0,%A0" CR_TAB
                  "clr %A0"     CR_TAB
                  "lsl %B0"     CR_TAB
                  "lsl %B0");

        case 11:
          *len = 5;
          return ("mov %B0,%A0" CR_TAB
                  "clr %A0"     CR_TAB
                  "lsl %B0"     CR_TAB
                  "lsl %B0"     CR_TAB
                  "lsl %B0");

        case 12:
          if (ldi_ok)
            {
              *len = 4;
              return ("mov %B0,%A0" CR_TAB
                      "clr %A0"     CR_TAB
                      "swap %B0"    CR_TAB
                      "andi %B0,0xf0");
            }
          if (scratch)
            {
              *len = 5;
              return ("mov %B0,%A0" CR_TAB
                      "clr %A0"     CR_TAB
                      "swap %B0"    CR_TAB
                      "ldi %3,0xf0" CR_TAB
                      "and %B0,%3");
            }
          *len = 6;
          return ("mov %B0,%A0" CR_TAB
                  "clr %A0"     CR_TAB
                  "lsl %B0"     CR_TAB
                  "lsl %B0"     CR_TAB
                  "lsl %B0"     CR_TAB
                  "lsl %B0");

        case 13:
          if (ldi_ok)
            {
              *len = 5;
              return ("mov %B0,%A0" CR_TAB
                      "clr %A0"     CR_TAB
                      "swap %B0"    CR_TAB
                      "lsl %B0"     CR_TAB
                      "andi %B0,0xe0");
            }
          if (AVR_HAVE_MUL && scratch)
            {
              *len = 5;
              return ("ldi %3,0x20" CR_TAB
                      "mul %A0,%3"  CR_TAB
                      "mov %B0,r0"  CR_TAB
                      "clr %A0"     CR_TAB
                      "clr __zero_reg__");
            }
          if (optimize_size && scratch)
            break;  /* 5 */
          if (scratch)
            {
              *len = 6;
              return ("mov %B0,%A0" CR_TAB
                      "clr %A0"     CR_TAB
                      "swap %B0"    CR_TAB
                      "lsl %B0"     CR_TAB
                      "ldi %3,0xe0" CR_TAB
                      "and %B0,%3");
            }
          if (AVR_HAVE_MUL)
            {
              *len = 6;
              return ("set"            CR_TAB
                      "bld r1,5"   CR_TAB
                      "mul %A0,r1" CR_TAB
                      "mov %B0,r0" CR_TAB
                      "clr %A0"    CR_TAB
                      "clr __zero_reg__");
            }
          *len = 7;
          return ("mov %B0,%A0" CR_TAB
                  "clr %A0"     CR_TAB
                  "lsl %B0"     CR_TAB
                  "lsl %B0"     CR_TAB
                  "lsl %B0"     CR_TAB
                  "lsl %B0"     CR_TAB
                  "lsl %B0");

        case 14:
          if (AVR_HAVE_MUL && ldi_ok)
            {
              *len = 5;
              return ("ldi %B0,0x40" CR_TAB
                      "mul %A0,%B0"  CR_TAB
                      "mov %B0,r0"   CR_TAB
                      "clr %A0"      CR_TAB
                      "clr __zero_reg__");
            }
          if (AVR_HAVE_MUL && scratch)
            {
              *len = 5;
              return ("ldi %3,0x40" CR_TAB
                      "mul %A0,%3"  CR_TAB
                      "mov %B0,r0"  CR_TAB
                      "clr %A0"     CR_TAB
                      "clr __zero_reg__");
            }
          if (optimize_size && ldi_ok)
            {
              *len = 5;
              return ("mov %B0,%A0" CR_TAB
                      "ldi %A0,6" "\n1:\t"
                      "lsl %B0"     CR_TAB
                      "dec %A0"     CR_TAB
                      "brne 1b");
            }
          if (optimize_size && scratch)
            break;  /* 5 */
          *len = 6;
          return ("clr %B0" CR_TAB
                  "lsr %A0" CR_TAB
                  "ror %B0" CR_TAB
                  "lsr %A0" CR_TAB
                  "ror %B0" CR_TAB
                  "clr %A0");

        case 15:
          *len = 4;
          return ("clr %B0" CR_TAB
                  "lsr %A0" CR_TAB
                  "ror %B0" CR_TAB
                  "clr %A0");
        }
      len = t;
    }
  out_shift_with_cnt ("lsl %A0" CR_TAB
                      "rol %B0", insn, operands, len, 2);
  return "";
}


/* 24-bit shift left */

const char*
avr_out_ashlpsi3 (rtx insn, rtx *op, int *plen)
{
  if (plen)
    *plen = 0;
  
  if (CONST_INT_P (op[2]))
    {
      switch (INTVAL (op[2]))
        {
        default:
          if (INTVAL (op[2]) < 24)
            break;

          return avr_asm_len ("clr %A0" CR_TAB
                              "clr %B0" CR_TAB
                              "clr %C0", op, plen, 3);

        case 8:
          {
            int reg0 = REGNO (op[0]);
            int reg1 = REGNO (op[1]);
            
            if (reg0 >= reg1)
              return avr_asm_len ("mov %C0,%B1"  CR_TAB
                                  "mov %B0,%A1"  CR_TAB
                                  "clr %A0", op, plen, 3);
            else
              return avr_asm_len ("clr %A0"      CR_TAB
                                  "mov %B0,%A1"  CR_TAB
                                  "mov %C0,%B1", op, plen, 3);
          }

        case 16:
          {
            int reg0 = REGNO (op[0]);
            int reg1 = REGNO (op[1]);

            if (reg0 + 2 != reg1)
              avr_asm_len ("mov %C0,%A0", op, plen, 1);
            
            return avr_asm_len ("clr %B0"  CR_TAB
                                "clr %A0", op, plen, 2);
          }

        case 23:
          return avr_asm_len ("clr %C0" CR_TAB
                              "lsr %A0" CR_TAB
                              "ror %C0" CR_TAB
                              "clr %B0" CR_TAB
                              "clr %A0", op, plen, 5);
        }
    }
  
  out_shift_with_cnt ("lsl %A0" CR_TAB
                      "rol %B0" CR_TAB
                      "rol %C0", insn, op, plen, 3);
  return "";
}


/* 32bit shift left ((long)x << i)   */

const char *
ashlsi3_out (rtx insn, rtx operands[], int *len)
{
  if (GET_CODE (operands[2]) == CONST_INT)
    {
      int k;
      int *t = len;
      
      if (!len)
        len = &k;
      
      switch (INTVAL (operands[2]))
        {
        default:
          if (INTVAL (operands[2]) < 32)
            break;

          if (AVR_HAVE_MOVW)
            return *len = 3, ("clr %D0" CR_TAB
                              "clr %C0" CR_TAB
                              "movw %A0,%C0");
          *len = 4;
          return ("clr %D0" CR_TAB
                  "clr %C0" CR_TAB
                  "clr %B0" CR_TAB
                  "clr %A0");

        case 8:
          {
            int reg0 = true_regnum (operands[0]);
            int reg1 = true_regnum (operands[1]);
            *len = 4;
            if (reg0 >= reg1)
              return ("mov %D0,%C1"  CR_TAB
                      "mov %C0,%B1"  CR_TAB
                      "mov %B0,%A1"  CR_TAB
                      "clr %A0");
            else
              return ("clr %A0"      CR_TAB
                      "mov %B0,%A1"  CR_TAB
                      "mov %C0,%B1"  CR_TAB
                      "mov %D0,%C1");
          }

        case 16:
          {
            int reg0 = true_regnum (operands[0]);
            int reg1 = true_regnum (operands[1]);
            if (reg0 + 2 == reg1)
              return *len = 2, ("clr %B0"      CR_TAB
                                "clr %A0");
            if (AVR_HAVE_MOVW)
              return *len = 3, ("movw %C0,%A1" CR_TAB
                                "clr %B0"      CR_TAB
                                "clr %A0");
            else
              return *len = 4, ("mov %C0,%A1"  CR_TAB
                                "mov %D0,%B1"  CR_TAB
                                "clr %B0"      CR_TAB
                                "clr %A0");
          }

        case 24:
          *len = 4;
          return ("mov %D0,%A1"  CR_TAB
                  "clr %C0"      CR_TAB
                  "clr %B0"      CR_TAB
                  "clr %A0");

        case 31:
          *len = 6;
          return ("clr %D0" CR_TAB
                  "lsr %A0" CR_TAB
                  "ror %D0" CR_TAB
                  "clr %C0" CR_TAB
                  "clr %B0" CR_TAB
                  "clr %A0");
        }
      len = t;
    }
  out_shift_with_cnt ("lsl %A0" CR_TAB
                      "rol %B0" CR_TAB
                      "rol %C0" CR_TAB
                      "rol %D0", insn, operands, len, 4);
  return "";
}

/* 8bit arithmetic shift right  ((signed char)x >> i) */

const char *
ashrqi3_out (rtx insn, rtx operands[], int *len)
{
  if (GET_CODE (operands[2]) == CONST_INT)
    {
      int k;

      if (!len)
        len = &k;

      switch (INTVAL (operands[2]))
        {
        case 1:
          *len = 1;
          return "asr %0";

        case 2:
          *len = 2;
          return ("asr %0" CR_TAB
                  "asr %0");

        case 3:
          *len = 3;
          return ("asr %0" CR_TAB
                  "asr %0" CR_TAB
                  "asr %0");

        case 4:
          *len = 4;
          return ("asr %0" CR_TAB
                  "asr %0" CR_TAB
                  "asr %0" CR_TAB
                  "asr %0");

        case 5:
          *len = 5;
          return ("asr %0" CR_TAB
                  "asr %0" CR_TAB
                  "asr %0" CR_TAB
                  "asr %0" CR_TAB
                  "asr %0");

        case 6:
          *len = 4;
          return ("bst %0,6"  CR_TAB
                  "lsl %0"    CR_TAB
                  "sbc %0,%0" CR_TAB
                  "bld %0,0");

        default:
          if (INTVAL (operands[2]) < 8)
            break;

          /* fall through */

        case 7:
          *len = 2;
          return ("lsl %0" CR_TAB
                  "sbc %0,%0");
        }
    }
  else if (CONSTANT_P (operands[2]))
    fatal_insn ("internal compiler error.  Incorrect shift:", insn);

  out_shift_with_cnt ("asr %0",
                      insn, operands, len, 1);
  return "";
}


/* 16bit arithmetic shift right  ((signed short)x >> i) */

const char *
ashrhi3_out (rtx insn, rtx operands[], int *len)
{
  if (GET_CODE (operands[2]) == CONST_INT)
    {
      int scratch = (GET_CODE (PATTERN (insn)) == PARALLEL);
      int ldi_ok = test_hard_reg_class (LD_REGS, operands[0]);
      int k;
      int *t = len;
      
      if (!len)
        len = &k;

      switch (INTVAL (operands[2]))
        {
        case 4:
        case 5:
          /* XXX try to optimize this too? */
          break;

        case 6:
          if (optimize_size)
            break;  /* scratch ? 5 : 6 */
          *len = 8;
          return ("mov __tmp_reg__,%A0" CR_TAB
                  "mov %A0,%B0"         CR_TAB
                  "lsl __tmp_reg__"     CR_TAB
                  "rol %A0"             CR_TAB
                  "sbc %B0,%B0"         CR_TAB
                  "lsl __tmp_reg__"     CR_TAB
                  "rol %A0"             CR_TAB
                  "rol %B0");

        case 7:
          *len = 4;
          return ("lsl %A0"     CR_TAB
                  "mov %A0,%B0" CR_TAB
                  "rol %A0"     CR_TAB
                  "sbc %B0,%B0");

        case 8:
          {
            int reg0 = true_regnum (operands[0]);
            int reg1 = true_regnum (operands[1]);

            if (reg0 == reg1)
              return *len = 3, ("mov %A0,%B0" CR_TAB
                                "lsl %B0"     CR_TAB
                                "sbc %B0,%B0");
            else 
              return *len = 4, ("mov %A0,%B1" CR_TAB
                                "clr %B0"     CR_TAB
                                "sbrc %A0,7"  CR_TAB
                                "dec %B0");
          }

        case 9:
          *len = 4;
          return ("mov %A0,%B0" CR_TAB
                  "lsl %B0"      CR_TAB
                  "sbc %B0,%B0" CR_TAB
                  "asr %A0");

        case 10:
          *len = 5;
          return ("mov %A0,%B0" CR_TAB
                  "lsl %B0"     CR_TAB
                  "sbc %B0,%B0" CR_TAB
                  "asr %A0"     CR_TAB
                  "asr %A0");

        case 11:
          if (AVR_HAVE_MUL && ldi_ok)
            {
              *len = 5;
              return ("ldi %A0,0x20" CR_TAB
                      "muls %B0,%A0" CR_TAB
                      "mov %A0,r1"   CR_TAB
                      "sbc %B0,%B0"  CR_TAB
                      "clr __zero_reg__");
            }
          if (optimize_size && scratch)
            break;  /* 5 */
          *len = 6;
          return ("mov %A0,%B0" CR_TAB
                  "lsl %B0"     CR_TAB
                  "sbc %B0,%B0" CR_TAB
                  "asr %A0"     CR_TAB
                  "asr %A0"     CR_TAB
                  "asr %A0");

        case 12:
          if (AVR_HAVE_MUL && ldi_ok)
            {
              *len = 5;
              return ("ldi %A0,0x10" CR_TAB
                      "muls %B0,%A0" CR_TAB
                      "mov %A0,r1"   CR_TAB
                      "sbc %B0,%B0"  CR_TAB
                      "clr __zero_reg__");
            }
          if (optimize_size && scratch)
            break;  /* 5 */
          *len = 7;
          return ("mov %A0,%B0" CR_TAB
                  "lsl %B0"     CR_TAB
                  "sbc %B0,%B0" CR_TAB
                  "asr %A0"     CR_TAB
                  "asr %A0"     CR_TAB
                  "asr %A0"     CR_TAB
                  "asr %A0");

        case 13:
          if (AVR_HAVE_MUL && ldi_ok)
            {
              *len = 5;
              return ("ldi %A0,0x08" CR_TAB
                      "muls %B0,%A0" CR_TAB
                      "mov %A0,r1"   CR_TAB
                      "sbc %B0,%B0"  CR_TAB
                      "clr __zero_reg__");
            }
          if (optimize_size)
            break;  /* scratch ? 5 : 7 */
          *len = 8;
          return ("mov %A0,%B0" CR_TAB
                  "lsl %B0"     CR_TAB
                  "sbc %B0,%B0" CR_TAB
                  "asr %A0"     CR_TAB
                  "asr %A0"     CR_TAB
                  "asr %A0"     CR_TAB
                  "asr %A0"     CR_TAB
                  "asr %A0");

        case 14:
          *len = 5;
          return ("lsl %B0"     CR_TAB
                  "sbc %A0,%A0" CR_TAB
                  "lsl %B0"     CR_TAB
                  "mov %B0,%A0" CR_TAB
                  "rol %A0");

        default:
          if (INTVAL (operands[2]) < 16)
            break;

          /* fall through */

        case 15:
          return *len = 3, ("lsl %B0"     CR_TAB
                            "sbc %A0,%A0" CR_TAB
                            "mov %B0,%A0");
        }
      len = t;
    }
  out_shift_with_cnt ("asr %B0" CR_TAB
                      "ror %A0", insn, operands, len, 2);
  return "";
}


/* 24-bit arithmetic shift right */

const char*
avr_out_ashrpsi3 (rtx insn, rtx *op, int *plen)
{
  int dest = REGNO (op[0]);
  int src = REGNO (op[1]);

  if (CONST_INT_P (op[2]))
    {
      if (plen)
        *plen = 0;
      
      switch (INTVAL (op[2]))
        {
        case 8:
          if (dest <= src)
            return avr_asm_len ("mov %A0,%B1" CR_TAB
                                "mov %B0,%C1" CR_TAB
                                "clr %C0"     CR_TAB
                                "sbrc %B0,7"  CR_TAB
                                "dec %C0", op, plen, 5);
          else
            return avr_asm_len ("clr %C0"     CR_TAB
                                "sbrc %C1,7"  CR_TAB
                                "dec %C0"     CR_TAB
                                "mov %B0,%C1" CR_TAB
                                "mov %A0,%B1", op, plen, 5);
          
        case 16:
          if (dest != src + 2)
            avr_asm_len ("mov %A0,%C1", op, plen, 1);
          
          return avr_asm_len ("clr %B0"     CR_TAB
                              "sbrc %A0,7"  CR_TAB
                              "com %B0"     CR_TAB
                              "mov %C0,%B0", op, plen, 4);

        default:
          if (INTVAL (op[2]) < 24)
            break;

          /* fall through */

        case 23:
          return avr_asm_len ("lsl %C0"     CR_TAB
                              "sbc %A0,%A0" CR_TAB
                              "mov %B0,%A0" CR_TAB
                              "mov %C0,%A0", op, plen, 4);
        } /* switch */
    }
  
  out_shift_with_cnt ("asr %C0" CR_TAB
                      "ror %B0" CR_TAB
                      "ror %A0", insn, op, plen, 3);
  return "";
}


/* 32bit arithmetic shift right  ((signed long)x >> i) */

const char *
ashrsi3_out (rtx insn, rtx operands[], int *len)
{
  if (GET_CODE (operands[2]) == CONST_INT)
    {
      int k;
      int *t = len;
      
      if (!len)
        len = &k;
      
      switch (INTVAL (operands[2]))
        {
        case 8:
          {
            int reg0 = true_regnum (operands[0]);
            int reg1 = true_regnum (operands[1]);
            *len=6;
            if (reg0 <= reg1)
              return ("mov %A0,%B1" CR_TAB
                      "mov %B0,%C1" CR_TAB
                      "mov %C0,%D1" CR_TAB
                      "clr %D0"     CR_TAB
                      "sbrc %C0,7"  CR_TAB
                      "dec %D0");
            else
              return ("clr %D0"     CR_TAB
                      "sbrc %D1,7"  CR_TAB
                      "dec %D0"     CR_TAB
                      "mov %C0,%D1" CR_TAB
                      "mov %B0,%C1" CR_TAB
                      "mov %A0,%B1");
          }
          
        case 16:
          {
            int reg0 = true_regnum (operands[0]);
            int reg1 = true_regnum (operands[1]);
            
            if (reg0 == reg1 + 2)
              return *len = 4, ("clr %D0"     CR_TAB
                                "sbrc %B0,7"  CR_TAB
                                "com %D0"     CR_TAB
                                "mov %C0,%D0");
            if (AVR_HAVE_MOVW)
              return *len = 5, ("movw %A0,%C1" CR_TAB
                                "clr %D0"      CR_TAB
                                "sbrc %B0,7"   CR_TAB
                                "com %D0"      CR_TAB
                                "mov %C0,%D0");
            else 
              return *len = 6, ("mov %B0,%D1" CR_TAB
                                "mov %A0,%C1" CR_TAB
                                "clr %D0"     CR_TAB
                                "sbrc %B0,7"  CR_TAB
                                "com %D0"     CR_TAB
                                "mov %C0,%D0");
          }

        case 24:
          return *len = 6, ("mov %A0,%D1" CR_TAB
                            "clr %D0"     CR_TAB
                            "sbrc %A0,7"  CR_TAB
                            "com %D0"     CR_TAB
                            "mov %B0,%D0" CR_TAB
                            "mov %C0,%D0");

        default:
          if (INTVAL (operands[2]) < 32)
            break;

          /* fall through */

        case 31:
          if (AVR_HAVE_MOVW)
            return *len = 4, ("lsl %D0"     CR_TAB
                              "sbc %A0,%A0" CR_TAB
                              "mov %B0,%A0" CR_TAB
                              "movw %C0,%A0");
          else
            return *len = 5, ("lsl %D0"     CR_TAB
                              "sbc %A0,%A0" CR_TAB
                              "mov %B0,%A0" CR_TAB
                              "mov %C0,%A0" CR_TAB
                              "mov %D0,%A0");
        }
      len = t;
    }
  out_shift_with_cnt ("asr %D0" CR_TAB
                      "ror %C0" CR_TAB
                      "ror %B0" CR_TAB
                      "ror %A0", insn, operands, len, 4);
  return "";
}

/* 8bit logic shift right ((unsigned char)x >> i) */

const char *
lshrqi3_out (rtx insn, rtx operands[], int *len)
{
  if (GET_CODE (operands[2]) == CONST_INT)
    {
      int k;

      if (!len)
        len = &k;
      
      switch (INTVAL (operands[2]))
        {
        default:
          if (INTVAL (operands[2]) < 8)
            break;

          *len = 1;
          return "clr %0";

        case 1:
          *len = 1;
          return "lsr %0";

        case 2:
          *len = 2;
          return ("lsr %0" CR_TAB
                  "lsr %0");
        case 3:
          *len = 3;
          return ("lsr %0" CR_TAB
                  "lsr %0" CR_TAB
                  "lsr %0");
          
        case 4:
          if (test_hard_reg_class (LD_REGS, operands[0]))
            {
              *len=2;
              return ("swap %0" CR_TAB
                      "andi %0,0x0f");
            }
          *len = 4;
          return ("lsr %0" CR_TAB
                  "lsr %0" CR_TAB
                  "lsr %0" CR_TAB
                  "lsr %0");
          
        case 5:
          if (test_hard_reg_class (LD_REGS, operands[0]))
            {
              *len = 3;
              return ("swap %0" CR_TAB
                      "lsr %0"  CR_TAB
                      "andi %0,0x7");
            }
          *len = 5;
          return ("lsr %0" CR_TAB
                  "lsr %0" CR_TAB
                  "lsr %0" CR_TAB
                  "lsr %0" CR_TAB
                  "lsr %0");
          
        case 6:
          if (test_hard_reg_class (LD_REGS, operands[0]))
            {
              *len = 4;
              return ("swap %0" CR_TAB
                      "lsr %0"  CR_TAB
                      "lsr %0"  CR_TAB
                      "andi %0,0x3");
            }
          *len = 6;
          return ("lsr %0" CR_TAB
                  "lsr %0" CR_TAB
                  "lsr %0" CR_TAB
                  "lsr %0" CR_TAB
                  "lsr %0" CR_TAB
                  "lsr %0");
          
        case 7:
          *len = 3;
          return ("rol %0" CR_TAB
                  "clr %0" CR_TAB
                  "rol %0");
        }
    }
  else if (CONSTANT_P (operands[2]))
    fatal_insn ("internal compiler error.  Incorrect shift:", insn);
  
  out_shift_with_cnt ("lsr %0",
                      insn, operands, len, 1);
  return "";
}

/* 16bit logic shift right ((unsigned short)x >> i) */

const char *
lshrhi3_out (rtx insn, rtx operands[], int *len)
{
  if (GET_CODE (operands[2]) == CONST_INT)
    {
      int scratch = (GET_CODE (PATTERN (insn)) == PARALLEL);
      int ldi_ok = test_hard_reg_class (LD_REGS, operands[0]);
      int k;
      int *t = len;

      if (!len)
        len = &k;
      
      switch (INTVAL (operands[2]))
        {
        default:
          if (INTVAL (operands[2]) < 16)
            break;

          *len = 2;
          return ("clr %B0" CR_TAB
                  "clr %A0");

        case 4:
          if (optimize_size && scratch)
            break;  /* 5 */
          if (ldi_ok)
            {
              *len = 6;
              return ("swap %B0"      CR_TAB
                      "swap %A0"      CR_TAB
                      "andi %A0,0x0f" CR_TAB
                      "eor %A0,%B0"   CR_TAB
                      "andi %B0,0x0f" CR_TAB
                      "eor %A0,%B0");
            }
          if (scratch)
            {
              *len = 7;
              return ("swap %B0"    CR_TAB
                      "swap %A0"    CR_TAB
                      "ldi %3,0x0f" CR_TAB
                      "and %A0,%3"      CR_TAB
                      "eor %A0,%B0" CR_TAB
                      "and %B0,%3"      CR_TAB
                      "eor %A0,%B0");
            }
          break;  /* optimize_size ? 6 : 8 */

        case 5:
          if (optimize_size)
            break;  /* scratch ? 5 : 6 */
          if (ldi_ok)
            {
              *len = 8;
              return ("lsr %B0"       CR_TAB
                      "ror %A0"       CR_TAB
                      "swap %B0"      CR_TAB
                      "swap %A0"      CR_TAB
                      "andi %A0,0x0f" CR_TAB
                      "eor %A0,%B0"   CR_TAB
                      "andi %B0,0x0f" CR_TAB
                      "eor %A0,%B0");
            }
          if (scratch)
            {
              *len = 9;
              return ("lsr %B0"     CR_TAB
                      "ror %A0"     CR_TAB
                      "swap %B0"    CR_TAB
                      "swap %A0"    CR_TAB
                      "ldi %3,0x0f" CR_TAB
                      "and %A0,%3"      CR_TAB
                      "eor %A0,%B0" CR_TAB
                      "and %B0,%3"      CR_TAB
                      "eor %A0,%B0");
            }
          break;  /* 10 */

        case 6:
          if (optimize_size)
            break;  /* scratch ? 5 : 6 */
          *len = 9;
          return ("clr __tmp_reg__" CR_TAB
                  "lsl %A0"         CR_TAB
                  "rol %B0"         CR_TAB
                  "rol __tmp_reg__" CR_TAB
                  "lsl %A0"         CR_TAB
                  "rol %B0"         CR_TAB
                  "rol __tmp_reg__" CR_TAB
                  "mov %A0,%B0"     CR_TAB
                  "mov %B0,__tmp_reg__");

        case 7:
          *len = 5;
          return ("lsl %A0"     CR_TAB
                  "mov %A0,%B0" CR_TAB
                  "rol %A0"     CR_TAB
                  "sbc %B0,%B0" CR_TAB
                  "neg %B0");

        case 8:
          return *len = 2, ("mov %A0,%B1" CR_TAB
                            "clr %B0");

        case 9:
          *len = 3;
          return ("mov %A0,%B0" CR_TAB
                  "clr %B0"     CR_TAB
                  "lsr %A0");

        case 10:
          *len = 4;
          return ("mov %A0,%B0" CR_TAB
                  "clr %B0"     CR_TAB
                  "lsr %A0"     CR_TAB
                  "lsr %A0");

        case 11:
          *len = 5;
          return ("mov %A0,%B0" CR_TAB
                  "clr %B0"     CR_TAB
                  "lsr %A0"     CR_TAB
                  "lsr %A0"     CR_TAB
                  "lsr %A0");

        case 12:
          if (ldi_ok)
            {
              *len = 4;
              return ("mov %A0,%B0" CR_TAB
                      "clr %B0"     CR_TAB
                      "swap %A0"    CR_TAB
                      "andi %A0,0x0f");
            }
          if (scratch)
            {
              *len = 5;
              return ("mov %A0,%B0" CR_TAB
                      "clr %B0"     CR_TAB
                      "swap %A0"    CR_TAB
                      "ldi %3,0x0f" CR_TAB
                      "and %A0,%3");
            }
          *len = 6;
          return ("mov %A0,%B0" CR_TAB
                  "clr %B0"     CR_TAB
                  "lsr %A0"     CR_TAB
                  "lsr %A0"     CR_TAB
                  "lsr %A0"     CR_TAB
                  "lsr %A0");

        case 13:
          if (ldi_ok)
            {
              *len = 5;
              return ("mov %A0,%B0" CR_TAB
                      "clr %B0"     CR_TAB
                      "swap %A0"    CR_TAB
                      "lsr %A0"     CR_TAB
                      "andi %A0,0x07");
            }
          if (AVR_HAVE_MUL && scratch)
            {
              *len = 5;
              return ("ldi %3,0x08" CR_TAB
                      "mul %B0,%3"  CR_TAB
                      "mov %A0,r1"  CR_TAB
                      "clr %B0"     CR_TAB
                      "clr __zero_reg__");
            }
          if (optimize_size && scratch)
            break;  /* 5 */
          if (scratch)
            {
              *len = 6;
              return ("mov %A0,%B0" CR_TAB
                      "clr %B0"     CR_TAB
                      "swap %A0"    CR_TAB
                      "lsr %A0"     CR_TAB
                      "ldi %3,0x07" CR_TAB
                      "and %A0,%3");
            }
          if (AVR_HAVE_MUL)
            {
              *len = 6;
              return ("set"            CR_TAB
                      "bld r1,3"   CR_TAB
                      "mul %B0,r1" CR_TAB
                      "mov %A0,r1" CR_TAB
                      "clr %B0"    CR_TAB
                      "clr __zero_reg__");
            }
          *len = 7;
          return ("mov %A0,%B0" CR_TAB
                  "clr %B0"     CR_TAB
                  "lsr %A0"     CR_TAB
                  "lsr %A0"     CR_TAB
                  "lsr %A0"     CR_TAB
                  "lsr %A0"     CR_TAB
                  "lsr %A0");

        case 14:
          if (AVR_HAVE_MUL && ldi_ok)
            {
              *len = 5;
              return ("ldi %A0,0x04" CR_TAB
                      "mul %B0,%A0"  CR_TAB
                      "mov %A0,r1"   CR_TAB
                      "clr %B0"      CR_TAB
                      "clr __zero_reg__");
            }
          if (AVR_HAVE_MUL && scratch)
            {
              *len = 5;
              return ("ldi %3,0x04" CR_TAB
                      "mul %B0,%3"  CR_TAB
                      "mov %A0,r1"  CR_TAB
                      "clr %B0"     CR_TAB
                      "clr __zero_reg__");
            }
          if (optimize_size && ldi_ok)
            {
              *len = 5;
              return ("mov %A0,%B0" CR_TAB
                      "ldi %B0,6" "\n1:\t"
                      "lsr %A0"     CR_TAB
                      "dec %B0"     CR_TAB
                      "brne 1b");
            }
          if (optimize_size && scratch)
            break;  /* 5 */
          *len = 6;
          return ("clr %A0" CR_TAB
                  "lsl %B0" CR_TAB
                  "rol %A0" CR_TAB
                  "lsl %B0" CR_TAB
                  "rol %A0" CR_TAB
                  "clr %B0");

        case 15:
          *len = 4;
          return ("clr %A0" CR_TAB
                  "lsl %B0" CR_TAB
                  "rol %A0" CR_TAB
                  "clr %B0");
        }
      len = t;
    }
  out_shift_with_cnt ("lsr %B0" CR_TAB
                      "ror %A0", insn, operands, len, 2);
  return "";
}


/* 24-bit logic shift right */

const char*
avr_out_lshrpsi3 (rtx insn, rtx *op, int *plen)
{
  int dest = REGNO (op[0]);
  int src = REGNO (op[1]);

  if (CONST_INT_P (op[2]))
    {
      if (plen)
        *plen = 0;
      
      switch (INTVAL (op[2]))
        {
        case 8:
          if (dest <= src)
            return avr_asm_len ("mov %A0,%B1" CR_TAB
                                "mov %B0,%C1" CR_TAB
                                "clr %C0", op, plen, 3);
          else
            return avr_asm_len ("clr %C0"     CR_TAB
                                "mov %B0,%C1" CR_TAB
                                "mov %A0,%B1", op, plen, 3);
          
        case 16:
          if (dest != src + 2)
            avr_asm_len ("mov %A0,%C1", op, plen, 1);
          
          return avr_asm_len ("clr %B0"  CR_TAB
                              "clr %C0", op, plen, 2);

        default:
          if (INTVAL (op[2]) < 24)
            break;

          /* fall through */

        case 23:
          return avr_asm_len ("clr %A0"    CR_TAB
                              "sbrc %C0,7" CR_TAB
                              "inc %A0"    CR_TAB
                              "clr %B0"    CR_TAB
                              "clr %C0", op, plen, 5);
        } /* switch */
    }
  
  out_shift_with_cnt ("lsr %C0" CR_TAB
                      "ror %B0" CR_TAB
                      "ror %A0", insn, op, plen, 3);
  return "";
}


/* 32bit logic shift right ((unsigned int)x >> i) */

const char *
lshrsi3_out (rtx insn, rtx operands[], int *len)
{
  if (GET_CODE (operands[2]) == CONST_INT)
    {
      int k;
      int *t = len;
      
      if (!len)
        len = &k;
      
      switch (INTVAL (operands[2]))
        {
        default:
          if (INTVAL (operands[2]) < 32)
            break;

          if (AVR_HAVE_MOVW)
            return *len = 3, ("clr %D0" CR_TAB
                              "clr %C0" CR_TAB
                              "movw %A0,%C0");
          *len = 4;
          return ("clr %D0" CR_TAB
                  "clr %C0" CR_TAB
                  "clr %B0" CR_TAB
                  "clr %A0");

        case 8:
          {
            int reg0 = true_regnum (operands[0]);
            int reg1 = true_regnum (operands[1]);
            *len = 4;
            if (reg0 <= reg1)
              return ("mov %A0,%B1" CR_TAB
                      "mov %B0,%C1" CR_TAB
                      "mov %C0,%D1" CR_TAB
                      "clr %D0");
            else
              return ("clr %D0"     CR_TAB
                      "mov %C0,%D1" CR_TAB
                      "mov %B0,%C1" CR_TAB
                      "mov %A0,%B1"); 
          }
          
        case 16:
          {
            int reg0 = true_regnum (operands[0]);
            int reg1 = true_regnum (operands[1]);

            if (reg0 == reg1 + 2)
              return *len = 2, ("clr %C0"     CR_TAB
                                "clr %D0");
            if (AVR_HAVE_MOVW)
              return *len = 3, ("movw %A0,%C1" CR_TAB
                                "clr %C0"      CR_TAB
                                "clr %D0");
            else
              return *len = 4, ("mov %B0,%D1" CR_TAB
                                "mov %A0,%C1" CR_TAB
                                "clr %C0"     CR_TAB
                                "clr %D0");
          }
          
        case 24:
          return *len = 4, ("mov %A0,%D1" CR_TAB
                            "clr %B0"     CR_TAB
                            "clr %C0"     CR_TAB
                            "clr %D0");

        case 31:
          *len = 6;
          return ("clr %A0"    CR_TAB
                  "sbrc %D0,7" CR_TAB
                  "inc %A0"    CR_TAB
                  "clr %B0"    CR_TAB
                  "clr %C0"    CR_TAB
                  "clr %D0");
        }
      len = t;
    }
  out_shift_with_cnt ("lsr %D0" CR_TAB
                      "ror %C0" CR_TAB
                      "ror %B0" CR_TAB
                      "ror %A0", insn, operands, len, 4);
  return "";
}


/* Output addition of register XOP[0] and compile time constant XOP[2]:

      XOP[0] = XOP[0] + XOP[2]

   and return "".  If PLEN == NULL, print assembler instructions to perform the
   addition; otherwise, set *PLEN to the length of the instruction sequence (in
   words) printed with PLEN == NULL.  XOP[3] is an 8-bit scratch register.
   CODE == PLUS:  perform addition by using ADD instructions.
   CODE == MINUS: perform addition by using SUB instructions.
   Set *PCC to effect on cc0 according to respective CC_* insn attribute.  */

static void
avr_out_plus_1 (rtx *xop, int *plen, enum rtx_code code, int *pcc)
{
  /* MODE of the operation.  */
  enum machine_mode mode = GET_MODE (xop[0]);

  /* Number of bytes to operate on.  */
  int i, n_bytes = GET_MODE_SIZE (mode);

  /* Value (0..0xff) held in clobber register op[3] or -1 if unknown.  */
  int clobber_val = -1;

  /* op[0]: 8-bit destination register
     op[1]: 8-bit const int
     op[2]: 8-bit scratch register */
  rtx op[3];

  /* Started the operation?  Before starting the operation we may skip
     adding 0.  This is no more true after the operation started because
     carry must be taken into account.  */
  bool started = false;

  /* Value to add.  There are two ways to add VAL: R += VAL and R -= -VAL.  */
  rtx xval = xop[2];

  /* Except in the case of ADIW with 16-bit register (see below)
     addition does not set cc0 in a usable way.  */
  
  *pcc = (MINUS == code) ? CC_SET_CZN : CC_CLOBBER;

  if (MINUS == code)
    xval = simplify_unary_operation (NEG, mode, xval, mode);

  op[2] = xop[3];

  if (plen)
    *plen = 0;

  for (i = 0; i < n_bytes; i++)
    {
      /* We operate byte-wise on the destination.  */
      rtx reg8 = simplify_gen_subreg (QImode, xop[0], mode, i);
      rtx xval8 = simplify_gen_subreg (QImode, xval, mode, i);

      /* 8-bit value to operate with this byte. */
      unsigned int val8 = UINTVAL (xval8) & GET_MODE_MASK (QImode);

      /* Registers R16..R31 can operate with immediate.  */
      bool ld_reg_p = test_hard_reg_class (LD_REGS, reg8);

      op[0] = reg8;
      op[1] = gen_int_mode (val8, QImode);

      /* To get usable cc0 no low-bytes must have been skipped.  */
      
      if (i && !started)
        *pcc = CC_CLOBBER;
      
      if (!started
          && i % 2 == 0
          && i + 2 <= n_bytes
          && test_hard_reg_class (ADDW_REGS, reg8))
        {
          rtx xval16 = simplify_gen_subreg (HImode, xval, mode, i);
          unsigned int val16 = UINTVAL (xval16) & GET_MODE_MASK (HImode);

          /* Registers R24, X, Y, Z can use ADIW/SBIW with constants < 64
             i.e. operate word-wise.  */

          if (val16 < 64)
            {
              if (val16 != 0)
                {
                  started = true;
                  avr_asm_len (code == PLUS ? "adiw %0,%1" : "sbiw %0,%1",
                               op, plen, 1);

                  if (n_bytes == 2 && PLUS == code)
                      *pcc = CC_SET_ZN;
                }

              i++;
              continue;
            }
        }

      if (val8 == 0)
        {
          if (started)
            avr_asm_len (code == PLUS
                         ? "adc %0,__zero_reg__" : "sbc %0,__zero_reg__",
                         op, plen, 1);
          continue;
        }
      else if ((val8 == 1 || val8 == 0xff)
               && !started
               && i == n_bytes - 1)
        {
          avr_asm_len ((code == PLUS) ^ (val8 == 1) ? "dec %0" : "inc %0",
                       op, plen, 1);
          break;
        }

      switch (code)
        {
        case PLUS:

          gcc_assert (plen != NULL || REG_P (op[2]));

          if (clobber_val != (int) val8)
            avr_asm_len ("ldi %2,%1", op, plen, 1);
          clobber_val = (int) val8;
              
          avr_asm_len (started ? "adc %0,%2" : "add %0,%2", op, plen, 1);

          break; /* PLUS */

        case MINUS:

          if (ld_reg_p)
            avr_asm_len (started ? "sbci %0,%1" : "subi %0,%1", op, plen, 1);
          else
            {
              gcc_assert (plen != NULL || REG_P (op[2]));

              if (clobber_val != (int) val8)
                avr_asm_len ("ldi %2,%1", op, plen, 1);
              clobber_val = (int) val8;
              
              avr_asm_len (started ? "sbc %0,%2" : "sub %0,%2", op, plen, 1);
            }

          break; /* MINUS */
          
        default:
          /* Unknown code */
          gcc_unreachable();
        }

      started = true;

    } /* for all sub-bytes */

  /* No output doesn't change cc0.  */
  
  if (plen && *plen == 0)
    *pcc = CC_NONE;
}


/* Output addition of register XOP[0] and compile time constant XOP[2]:

      XOP[0] = XOP[0] + XOP[2]

   and return "".  If PLEN == NULL, print assembler instructions to perform the
   addition; otherwise, set *PLEN to the length of the instruction sequence (in
   words) printed with PLEN == NULL.
   If PCC != 0 then set *PCC to the the instruction sequence's effect on the
   condition code (with respect to XOP[0]).  */

const char*
avr_out_plus (rtx *xop, int *plen, int *pcc)
{
  int len_plus, len_minus;
  int cc_plus, cc_minus, cc_dummy;

  if (!pcc)
    pcc = &cc_dummy;
                                   
  /* Work out if  XOP[0] += XOP[2]  is better or  XOP[0] -= -XOP[2].  */
  
  avr_out_plus_1 (xop, &len_plus, PLUS, &cc_plus);
  avr_out_plus_1 (xop, &len_minus, MINUS, &cc_minus);

  /* Prefer MINUS over PLUS if size is equal because it sets cc0.  */
  
  if (plen)
    {
      *plen = (len_minus <= len_plus) ? len_minus : len_plus;
      *pcc  = (len_minus <= len_plus) ? cc_minus : cc_plus;
    }
  else if (len_minus <= len_plus)
    avr_out_plus_1 (xop, NULL, MINUS, pcc);
  else
    avr_out_plus_1 (xop, NULL, PLUS, pcc);

  return "";
}


/* Same as above but XOP has just 3 entries.
   Supply a dummy 4th operand.  */

const char*
avr_out_plus_noclobber (rtx *xop, int *plen, int *pcc)
{
  rtx op[4];

  op[0] = xop[0];
  op[1] = xop[1];
  op[2] = xop[2];
  op[3] = NULL_RTX;

  return avr_out_plus (op, plen, pcc);
}


/* Prepare operands of adddi3_const_insn to be used with avr_out_plus_1.  */

const char*
avr_out_plus64 (rtx addend, int *plen)
{
  int cc_dummy;
  rtx op[4];

  op[0] = gen_rtx_REG (DImode, 18);
  op[1] = op[0];
  op[2] = addend;
  op[3] = NULL_RTX;

  avr_out_plus_1 (op, plen, MINUS, &cc_dummy);

  return "";
}

/* Output bit operation (IOR, AND, XOR) with register XOP[0] and compile
   time constant XOP[2]:

      XOP[0] = XOP[0] <op> XOP[2]

   and return "".  If PLEN == NULL, print assembler instructions to perform the
   operation; otherwise, set *PLEN to the length of the instruction sequence
   (in words) printed with PLEN == NULL.  XOP[3] is either an 8-bit clobber
   register or SCRATCH if no clobber register is needed for the operation.  */

const char*
avr_out_bitop (rtx insn, rtx *xop, int *plen)
{
  /* CODE and MODE of the operation.  */
  enum rtx_code code = GET_CODE (SET_SRC (single_set (insn)));
  enum machine_mode mode = GET_MODE (xop[0]);

  /* Number of bytes to operate on.  */
  int i, n_bytes = GET_MODE_SIZE (mode);

  /* Value of T-flag (0 or 1) or -1 if unknow.  */
  int set_t = -1;

  /* Value (0..0xff) held in clobber register op[3] or -1 if unknown.  */
  int clobber_val = -1;

  /* op[0]: 8-bit destination register
     op[1]: 8-bit const int
     op[2]: 8-bit clobber register or SCRATCH
     op[3]: 8-bit register containing 0xff or NULL_RTX  */
  rtx op[4];

  op[2] = xop[3];
  op[3] = NULL_RTX;

  if (plen)
    *plen = 0;

  for (i = 0; i < n_bytes; i++)
    {
      /* We operate byte-wise on the destination.  */
      rtx reg8 = simplify_gen_subreg (QImode, xop[0], mode, i);
      rtx xval8 = simplify_gen_subreg (QImode, xop[2], mode, i);

      /* 8-bit value to operate with this byte. */
      unsigned int val8 = UINTVAL (xval8) & GET_MODE_MASK (QImode);

      /* Number of bits set in the current byte of the constant.  */
      int pop8 = avr_popcount (val8);

      /* Registers R16..R31 can operate with immediate.  */
      bool ld_reg_p = test_hard_reg_class (LD_REGS, reg8);

      op[0] = reg8;
      op[1] = GEN_INT (val8);
    
      switch (code)
        {
        case IOR:

          if (0 == pop8)
            continue;
          else if (ld_reg_p)
            avr_asm_len ("ori %0,%1", op, plen, 1);
          else if (1 == pop8)
            {
              if (set_t != 1)
                avr_asm_len ("set", op, plen, 1);
              set_t = 1;
              
              op[1] = GEN_INT (exact_log2 (val8));
              avr_asm_len ("bld %0,%1", op, plen, 1);
            }
          else if (8 == pop8)
            {
              if (op[3] != NULL_RTX)
                avr_asm_len ("mov %0,%3", op, plen, 1);
              else
                avr_asm_len ("clr %0" CR_TAB
                             "dec %0", op, plen, 2);

              op[3] = op[0];
            }
          else
            {
              if (clobber_val != (int) val8)
                avr_asm_len ("ldi %2,%1", op, plen, 1);
              clobber_val = (int) val8;
              
              avr_asm_len ("or %0,%2", op, plen, 1);
            }

          continue; /* IOR */

        case AND:

          if (8 == pop8)
            continue;
          else if (0 == pop8)
            avr_asm_len ("clr %0", op, plen, 1);
          else if (ld_reg_p)
            avr_asm_len ("andi %0,%1", op, plen, 1);
          else if (7 == pop8)
            {
              if (set_t != 0)
                avr_asm_len ("clt", op, plen, 1);
              set_t = 0;
              
              op[1] = GEN_INT (exact_log2 (GET_MODE_MASK (QImode) & ~val8));
              avr_asm_len ("bld %0,%1", op, plen, 1);
            }
          else
            {
              if (clobber_val != (int) val8)
                avr_asm_len ("ldi %2,%1", op, plen, 1);
              clobber_val = (int) val8;
              
              avr_asm_len ("and %0,%2", op, plen, 1);
            }

          continue; /* AND */
          
        case XOR:

          if (0 == pop8)
            continue;
          else if (8 == pop8)
            avr_asm_len ("com %0", op, plen, 1);
          else if (ld_reg_p && val8 == (1 << 7))
            avr_asm_len ("subi %0,%1", op, plen, 1);
          else
            {
              if (clobber_val != (int) val8)
                avr_asm_len ("ldi %2,%1", op, plen, 1);
              clobber_val = (int) val8;
              
              avr_asm_len ("eor %0,%2", op, plen, 1);
            }

          continue; /* XOR */
          
        default:
          /* Unknown rtx_code */
          gcc_unreachable();
        }
    } /* for all sub-bytes */

  return "";
}


/* PLEN == NULL: Output code to add CONST_INT OP[0] to SP.
   PLEN != NULL: Set *PLEN to the length of that sequence.
   Return "".  */

const char*
avr_out_addto_sp (rtx *op, int *plen)
{
  int pc_len = AVR_2_BYTE_PC ? 2 : 3;
  int addend = INTVAL (op[0]);

  if (plen)
    *plen = 0;

  if (addend < 0)
    {
      if (flag_verbose_asm || flag_print_asm_name)
        avr_asm_len (ASM_COMMENT_START "SP -= %n0", op, plen, 0);
  
      while (addend <= -pc_len)
        {
          addend += pc_len;
          avr_asm_len ("rcall .", op, plen, 1);
        }

      while (addend++ < 0)
        avr_asm_len ("push __zero_reg__", op, plen, 1);
    }
  else if (addend > 0)
    {
      if (flag_verbose_asm || flag_print_asm_name)
        avr_asm_len (ASM_COMMENT_START "SP += %0", op, plen, 0);

      while (addend-- > 0)
        avr_asm_len ("pop __tmp_reg__", op, plen, 1);
    }

  return "";
}


/* Create RTL split patterns for byte sized rotate expressions.  This
  produces a series of move instructions and considers overlap situations.
  Overlapping non-HImode operands need a scratch register.  */

bool
avr_rotate_bytes (rtx operands[])
{
    int i, j;
    enum machine_mode mode = GET_MODE (operands[0]);
    bool overlapped = reg_overlap_mentioned_p (operands[0], operands[1]);
    bool same_reg = rtx_equal_p (operands[0], operands[1]);
    int num = INTVAL (operands[2]);
    rtx scratch = operands[3];
    /* Work out if byte or word move is needed.  Odd byte rotates need QImode.
       Word move if no scratch is needed, otherwise use size of scratch.  */
    enum machine_mode move_mode = QImode;
    int move_size, offset, size;

    if (num & 0xf)
      move_mode = QImode;
    else if ((mode == SImode && !same_reg) || !overlapped)
      move_mode = HImode;
    else
      move_mode = GET_MODE (scratch);

    /* Force DI rotate to use QI moves since other DI moves are currently split
       into QI moves so forward propagation works better.  */
    if (mode == DImode)
      move_mode = QImode;
    /* Make scratch smaller if needed.  */
    if (SCRATCH != GET_CODE (scratch)
        && HImode == GET_MODE (scratch)
        && QImode == move_mode)
      scratch = simplify_gen_subreg (move_mode, scratch, HImode, 0); 

    move_size = GET_MODE_SIZE (move_mode);
    /* Number of bytes/words to rotate.  */
    offset = (num  >> 3) / move_size;
    /* Number of moves needed.  */
    size = GET_MODE_SIZE (mode) / move_size;
    /* Himode byte swap is special case to avoid a scratch register.  */
    if (mode == HImode && same_reg)
      {
        /* HImode byte swap, using xor.  This is as quick as using scratch.  */
        rtx src, dst;
        src = simplify_gen_subreg (move_mode, operands[1], mode, 0);
        dst = simplify_gen_subreg (move_mode, operands[0], mode, 1);
        if (!rtx_equal_p (dst, src))
          {
             emit_move_insn (dst, gen_rtx_XOR (QImode, dst, src));
             emit_move_insn (src, gen_rtx_XOR (QImode, src, dst));
             emit_move_insn (dst, gen_rtx_XOR (QImode, dst, src));
          }
      }    
    else  
      {
#define MAX_SIZE 8 /* GET_MODE_SIZE (DImode) / GET_MODE_SIZE (QImode)  */
        /* Create linked list of moves to determine move order.  */
        struct {
          rtx src, dst;
          int links;
        } move[MAX_SIZE + 8];
        int blocked, moves;

        gcc_assert (size <= MAX_SIZE);
        /* Generate list of subreg moves.  */
        for (i = 0; i < size; i++)
          {
            int from = i;
            int to = (from + offset) % size;          
            move[i].src = simplify_gen_subreg (move_mode, operands[1],
                                                mode, from * move_size);
            move[i].dst = simplify_gen_subreg (move_mode, operands[0],
                                                mode, to   * move_size);
            move[i].links = -1;
           }
        /* Mark dependence where a dst of one move is the src of another move.
           The first move is a conflict as it must wait until second is
           performed.  We ignore moves to self - we catch this later.  */
        if (overlapped)
          for (i = 0; i < size; i++)
            if (reg_overlap_mentioned_p (move[i].dst, operands[1]))
              for (j = 0; j < size; j++)
                if (j != i && rtx_equal_p (move[j].src, move[i].dst))
                  {
                    /* The dst of move i is the src of move j.  */
                    move[i].links = j;
                    break;
                  }

        blocked = -1;
        moves = 0;
        /* Go through move list and perform non-conflicting moves.  As each
           non-overlapping move is made, it may remove other conflicts
           so the process is repeated until no conflicts remain.  */
        do
          {
            blocked = -1;
            moves = 0;
            /* Emit move where dst is not also a src or we have used that
               src already.  */
            for (i = 0; i < size; i++)
              if (move[i].src != NULL_RTX)
                {
                  if (move[i].links == -1
                      || move[move[i].links].src == NULL_RTX)
                    {
                      moves++;
                      /* Ignore NOP moves to self.  */
                      if (!rtx_equal_p (move[i].dst, move[i].src))
                        emit_move_insn (move[i].dst, move[i].src);

                      /* Remove  conflict from list.  */
                      move[i].src = NULL_RTX;
                    }
                  else
                    blocked = i;
                }

            /* Check for deadlock. This is when no moves occurred and we have
               at least one blocked move.  */
            if (moves == 0 && blocked != -1)
              {
                /* Need to use scratch register to break deadlock.
                   Add move to put dst of blocked move into scratch.
                   When this move occurs, it will break chain deadlock.
                   The scratch register is substituted for real move.  */

                gcc_assert (SCRATCH != GET_CODE (scratch));

                move[size].src = move[blocked].dst;
                move[size].dst =  scratch;
                /* Scratch move is never blocked.  */
                move[size].links = -1; 
                /* Make sure we have valid link.  */
                gcc_assert (move[blocked].links != -1);
                /* Replace src of  blocking move with scratch reg.  */
                move[move[blocked].links].src = scratch;
                /* Make dependent on scratch move occuring.  */
                move[blocked].links = size; 
                size=size+1;
              }
          }
        while (blocked != -1);
      }
    return true;
}

/* Modifies the length assigned to instruction INSN
   LEN is the initially computed length of the insn.  */

int
adjust_insn_length (rtx insn, int len)
{
  rtx *op = recog_data.operand;
  enum attr_adjust_len adjust_len;

  /* Some complex insns don't need length adjustment and therefore
     the length need not/must not be adjusted for these insns.
     It is easier to state this in an insn attribute "adjust_len" than
     to clutter up code here...  */
  
  if (-1 == recog_memoized (insn))
    {
      return len;
    }

  /* Read from insn attribute "adjust_len" if/how length is to be adjusted.  */

  adjust_len = get_attr_adjust_len (insn);

  if (adjust_len == ADJUST_LEN_NO)
    {
      /* Nothing to adjust: The length from attribute "length" is fine.
         This is the default.  */
      
      return len;
    }
  
  /* Extract insn's operands.  */
  
  extract_constrain_insn_cached (insn);
  
  /* Dispatch to right function.  */
  
  switch (adjust_len)
    {
    case ADJUST_LEN_RELOAD_IN16: output_reload_inhi (op, op[2], &len); break;
    case ADJUST_LEN_RELOAD_IN24: avr_out_reload_inpsi (op, op[2], &len); break;
    case ADJUST_LEN_RELOAD_IN32: output_reload_insisf (op, op[2], &len); break;
      
    case ADJUST_LEN_OUT_BITOP: avr_out_bitop (insn, op, &len); break;
      
    case ADJUST_LEN_OUT_PLUS: avr_out_plus (op, &len, NULL); break;
    case ADJUST_LEN_PLUS64: avr_out_plus64 (op[0], &len); break;
    case ADJUST_LEN_OUT_PLUS_NOCLOBBER:
      avr_out_plus_noclobber (op, &len, NULL); break;

    case ADJUST_LEN_ADDTO_SP: avr_out_addto_sp (op, &len); break;
      
    case ADJUST_LEN_MOV8:  output_movqi (insn, op, &len); break;
    case ADJUST_LEN_MOV16: output_movhi (insn, op, &len); break;
    case ADJUST_LEN_MOV24: avr_out_movpsi (insn, op, &len); break;
    case ADJUST_LEN_MOV32: output_movsisf (insn, op, &len); break;
    case ADJUST_LEN_MOVMEM: avr_out_movmem (insn, op, &len); break;
    case ADJUST_LEN_XLOAD: avr_out_xload (insn, op, &len); break;

    case ADJUST_LEN_TSTHI: avr_out_tsthi (insn, op, &len); break;
    case ADJUST_LEN_TSTPSI: avr_out_tstpsi (insn, op, &len); break;
    case ADJUST_LEN_TSTSI: avr_out_tstsi (insn, op, &len); break;
    case ADJUST_LEN_COMPARE: avr_out_compare (insn, op, &len); break;
    case ADJUST_LEN_COMPARE64: avr_out_compare64 (insn, op, &len); break;

    case ADJUST_LEN_LSHRQI: lshrqi3_out (insn, op, &len); break;
    case ADJUST_LEN_LSHRHI: lshrhi3_out (insn, op, &len); break;
    case ADJUST_LEN_LSHRSI: lshrsi3_out (insn, op, &len); break;

    case ADJUST_LEN_ASHRQI: ashrqi3_out (insn, op, &len); break;
    case ADJUST_LEN_ASHRHI: ashrhi3_out (insn, op, &len); break;
    case ADJUST_LEN_ASHRSI: ashrsi3_out (insn, op, &len); break;

    case ADJUST_LEN_ASHLQI: ashlqi3_out (insn, op, &len); break;
    case ADJUST_LEN_ASHLHI: ashlhi3_out (insn, op, &len); break;
    case ADJUST_LEN_ASHLSI: ashlsi3_out (insn, op, &len); break;
      
    case ADJUST_LEN_ASHLPSI: avr_out_ashlpsi3 (insn, op, &len); break;
    case ADJUST_LEN_ASHRPSI: avr_out_ashrpsi3 (insn, op, &len); break;
    case ADJUST_LEN_LSHRPSI: avr_out_lshrpsi3 (insn, op, &len); break;

    case ADJUST_LEN_CALL: len = AVR_HAVE_JMP_CALL ? 2 : 1; break;

    case ADJUST_LEN_INSERT_BITS: avr_out_insert_bits (op, &len); break;

    default:
      gcc_unreachable();
    }

  return len;
}

/* Return nonzero if register REG dead after INSN.  */

int
reg_unused_after (rtx insn, rtx reg)
{
  return (dead_or_set_p (insn, reg)
          || (REG_P(reg) && _reg_unused_after (insn, reg)));
}

/* Return nonzero if REG is not used after INSN.
   We assume REG is a reload reg, and therefore does
   not live past labels.  It may live past calls or jumps though.  */

int
_reg_unused_after (rtx insn, rtx reg)
{
  enum rtx_code code;
  rtx set;

  /* If the reg is set by this instruction, then it is safe for our
     case.  Disregard the case where this is a store to memory, since
     we are checking a register used in the store address.  */
  set = single_set (insn);
  if (set && GET_CODE (SET_DEST (set)) != MEM
      && reg_overlap_mentioned_p (reg, SET_DEST (set)))
    return 1;

  while ((insn = NEXT_INSN (insn)))
    {
      rtx set;
      code = GET_CODE (insn);

#if 0
      /* If this is a label that existed before reload, then the register
         if dead here.  However, if this is a label added by reorg, then
         the register may still be live here.  We can't tell the difference,
         so we just ignore labels completely.  */
      if (code == CODE_LABEL)
        return 1;
      /* else */
#endif

      if (!INSN_P (insn))
        continue;

      if (code == JUMP_INSN)
        return 0;

      /* If this is a sequence, we must handle them all at once.
         We could have for instance a call that sets the target register,
         and an insn in a delay slot that uses the register.  In this case,
         we must return 0.  */
      else if (code == INSN && GET_CODE (PATTERN (insn)) == SEQUENCE)
        {
          int i;
          int retval = 0;

          for (i = 0; i < XVECLEN (PATTERN (insn), 0); i++)
            {
              rtx this_insn = XVECEXP (PATTERN (insn), 0, i);
              rtx set = single_set (this_insn);

              if (GET_CODE (this_insn) == CALL_INSN)
                code = CALL_INSN;
              else if (GET_CODE (this_insn) == JUMP_INSN)
                {
                  if (INSN_ANNULLED_BRANCH_P (this_insn))
                    return 0;
                  code = JUMP_INSN;
                }

              if (set && reg_overlap_mentioned_p (reg, SET_SRC (set)))
                return 0;
              if (set && reg_overlap_mentioned_p (reg, SET_DEST (set)))
                {
                  if (GET_CODE (SET_DEST (set)) != MEM)
                    retval = 1;
                  else
                    return 0;
                }
              if (set == 0
                  && reg_overlap_mentioned_p (reg, PATTERN (this_insn)))
                return 0;
            }
          if (retval == 1)
            return 1;
          else if (code == JUMP_INSN)
            return 0;
        }

      if (code == CALL_INSN)
        {
          rtx tem;
          for (tem = CALL_INSN_FUNCTION_USAGE (insn); tem; tem = XEXP (tem, 1))
            if (GET_CODE (XEXP (tem, 0)) == USE
                && REG_P (XEXP (XEXP (tem, 0), 0))
                && reg_overlap_mentioned_p (reg, XEXP (XEXP (tem, 0), 0)))
              return 0;
          if (call_used_regs[REGNO (reg)]) 
            return 1;
        }

      set = single_set (insn);

      if (set && reg_overlap_mentioned_p (reg, SET_SRC (set)))
        return 0;
      if (set && reg_overlap_mentioned_p (reg, SET_DEST (set)))
        return GET_CODE (SET_DEST (set)) != MEM;
      if (set == 0 && reg_overlap_mentioned_p (reg, PATTERN (insn)))
        return 0;
    }
  return 1;
}


/* Return RTX that represents the lower 16 bits of a constant address.
   Unfortunately, simplify_gen_subreg does not handle this case.  */

static rtx
avr_const_address_lo16 (rtx x)
{
  rtx lo16;
  
  switch (GET_CODE (x))
    {
    default:
      break;
      
    case CONST:
      if (PLUS == GET_CODE (XEXP (x, 0))
          && SYMBOL_REF == GET_CODE (XEXP (XEXP (x, 0), 0))
          && CONST_INT_P (XEXP (XEXP (x, 0), 1)))
        {
          HOST_WIDE_INT offset = INTVAL (XEXP (XEXP (x, 0), 1));
          const char *name = XSTR (XEXP (XEXP (x, 0), 0), 0);
          
          lo16 = gen_rtx_SYMBOL_REF (Pmode, ggc_strdup (name));
          lo16 = gen_rtx_CONST (Pmode, plus_constant (lo16, offset));
          
          return lo16;
        }
      
      break;
      
    case SYMBOL_REF:
      {
        const char *name = XSTR (x, 0);
        
        return gen_rtx_SYMBOL_REF (Pmode, ggc_strdup (name));
      }
    }
  
  avr_edump ("\n%?: %r\n", x);
  gcc_unreachable();
}


/* Target hook for assembling integer objects.  The AVR version needs
   special handling for references to certain labels.  */

static bool
avr_assemble_integer (rtx x, unsigned int size, int aligned_p)
{
  if (size == POINTER_SIZE / BITS_PER_UNIT && aligned_p
      && text_segment_operand (x, VOIDmode) )
    {
      fputs ("\t.word\tgs(", asm_out_file);
      output_addr_const (asm_out_file, x);
      fputs (")\n", asm_out_file);
      
      return true;
    }
  else if (GET_MODE (x) == PSImode)
    {
      default_assemble_integer (avr_const_address_lo16 (x),
                                GET_MODE_SIZE (HImode), aligned_p);
      
      fputs ("\t.warning\t\"assembling 24-bit address needs binutils"
             " extension for hh8(", asm_out_file);
      output_addr_const (asm_out_file, x);
      fputs (")\"\n", asm_out_file);
      
      fputs ("\t.byte\t0\t" ASM_COMMENT_START " hh8(", asm_out_file);
      output_addr_const (asm_out_file, x);
      fputs (")\n", asm_out_file);
      
      return true;
    }
  
  return default_assemble_integer (x, size, aligned_p);
}


/* Worker function for ASM_DECLARE_FUNCTION_NAME.  */

void
avr_asm_declare_function_name (FILE *file, const char *name, tree decl)
{

  /* If the function has the 'signal' or 'interrupt' attribute, test to
     make sure that the name of the function is "__vector_NN" so as to
     catch when the user misspells the interrupt vector name.  */

  if (cfun->machine->is_interrupt)
    {
      if (!STR_PREFIX_P (name, "__vector"))
        {
          warning_at (DECL_SOURCE_LOCATION (decl), 0,
                      "%qs appears to be a misspelled interrupt handler",
                      name);
        }
    }
  else if (cfun->machine->is_signal)
    {
      if (!STR_PREFIX_P (name, "__vector"))
        {
           warning_at (DECL_SOURCE_LOCATION (decl), 0,
                       "%qs appears to be a misspelled signal handler",
                       name);
        }
    }

  ASM_OUTPUT_TYPE_DIRECTIVE (file, name, "function");
  ASM_OUTPUT_LABEL (file, name);
}


/* Return value is nonzero if pseudos that have been
   assigned to registers of class CLASS would likely be spilled
   because registers of CLASS are needed for spill registers.  */

static bool
avr_class_likely_spilled_p (reg_class_t c)
{
  return (c != ALL_REGS && c != ADDW_REGS);
}

/* Valid attributes:
   progmem - put data to program memory;
   signal - make a function to be hardware interrupt. After function
   prologue interrupts are disabled;
   interrupt - make a function to be hardware interrupt. After function
   prologue interrupts are enabled;
   naked     - don't generate function prologue/epilogue and `ret' command.

   Only `progmem' attribute valid for type.  */

/* Handle a "progmem" attribute; arguments as in
   struct attribute_spec.handler.  */
static tree
avr_handle_progmem_attribute (tree *node, tree name,
                              tree args ATTRIBUTE_UNUSED,
                              int flags ATTRIBUTE_UNUSED,
                              bool *no_add_attrs)
{
  if (DECL_P (*node))
    {
      if (TREE_CODE (*node) == TYPE_DECL)
        {
          /* This is really a decl attribute, not a type attribute,
             but try to handle it for GCC 3.0 backwards compatibility.  */

          tree type = TREE_TYPE (*node);
          tree attr = tree_cons (name, args, TYPE_ATTRIBUTES (type));
          tree newtype = build_type_attribute_variant (type, attr);

          TYPE_MAIN_VARIANT (newtype) = TYPE_MAIN_VARIANT (type);
          TREE_TYPE (*node) = newtype;
          *no_add_attrs = true;
        }
      else if (TREE_STATIC (*node) || DECL_EXTERNAL (*node))
        {
          *no_add_attrs = false;
        }
      else
        {
          warning (OPT_Wattributes, "%qE attribute ignored",
                   name);
          *no_add_attrs = true;
        }
    }

  return NULL_TREE;
}

/* Handle an attribute requiring a FUNCTION_DECL; arguments as in
   struct attribute_spec.handler.  */

static tree
avr_handle_fndecl_attribute (tree *node, tree name,
                             tree args ATTRIBUTE_UNUSED,
                             int flags ATTRIBUTE_UNUSED,
                             bool *no_add_attrs)
{
  if (TREE_CODE (*node) != FUNCTION_DECL)
    {
      warning (OPT_Wattributes, "%qE attribute only applies to functions",
               name);
      *no_add_attrs = true;
    }

  return NULL_TREE;
}

static tree
avr_handle_fntype_attribute (tree *node, tree name,
                             tree args ATTRIBUTE_UNUSED,
                             int flags ATTRIBUTE_UNUSED,
                             bool *no_add_attrs)
{
  if (TREE_CODE (*node) != FUNCTION_TYPE)
    {
      warning (OPT_Wattributes, "%qE attribute only applies to functions",
               name);
      *no_add_attrs = true;
    }

  return NULL_TREE;
}


/* AVR attributes.  */
static const struct attribute_spec
avr_attribute_table[] =
{
  /* { name, min_len, max_len, decl_req, type_req, fn_type_req, handler,
       affects_type_identity } */
  { "progmem",   0, 0, false, false, false,  avr_handle_progmem_attribute,
    false },
  { "signal",    0, 0, true,  false, false,  avr_handle_fndecl_attribute,
    false },
  { "interrupt", 0, 0, true,  false, false,  avr_handle_fndecl_attribute,
    false },
  { "naked",     0, 0, false, true,  true,   avr_handle_fntype_attribute,
    false },
  { "OS_task",   0, 0, false, true,  true,   avr_handle_fntype_attribute,
    false },
  { "OS_main",   0, 0, false, true,  true,   avr_handle_fntype_attribute,
    false },
  { NULL,        0, 0, false, false, false, NULL, false }
};


/* Look if DECL shall be placed in program memory space by
   means of attribute `progmem' or some address-space qualifier.
   Return non-zero if DECL is data that must end up in Flash and
   zero if the data lives in RAM (.bss, .data, .rodata, ...).
   
   Return 2   if DECL is located in 24-bit flash address-space
   Return 1   if DECL is located in 16-bit flash address-space
   Return -1  if attribute `progmem' occurs in DECL or ATTRIBUTES
   Return 0   otherwise  */

int
avr_progmem_p (tree decl, tree attributes)
{
  tree a;

  if (TREE_CODE (decl) != VAR_DECL)
    return 0;

  if (avr_decl_memx_p (decl))
    return 2;

  if (avr_decl_flash_p (decl))
    return 1;

  if (NULL_TREE
      != lookup_attribute ("progmem", attributes))
    return -1;

  a = decl;
 
  do
    a = TREE_TYPE(a);
  while (TREE_CODE (a) == ARRAY_TYPE);

  if (a == error_mark_node)
    return 0;

  if (NULL_TREE != lookup_attribute ("progmem", TYPE_ATTRIBUTES (a)))
    return -1;
  
  return 0;
}


/* Scan type TYP for pointer references to address space ASn.
   Return ADDR_SPACE_GENERIC (i.e. 0) if all pointers targeting
   the AS are also declared to be CONST.
   Otherwise, return the respective addres space, i.e. a value != 0.  */
   
static addr_space_t
avr_nonconst_pointer_addrspace (tree typ)
{
  while (ARRAY_TYPE == TREE_CODE (typ))
    typ = TREE_TYPE (typ);

  if (POINTER_TYPE_P (typ))
    {
      tree target = TREE_TYPE (typ);

      /* Pointer to function: Test the function's return type.  */
      
      if (FUNCTION_TYPE == TREE_CODE (target))
        return avr_nonconst_pointer_addrspace (TREE_TYPE (target));

      /* "Ordinary" pointers... */

      while (TREE_CODE (target) == ARRAY_TYPE)
        target = TREE_TYPE (target);

      if (!ADDR_SPACE_GENERIC_P (TYPE_ADDR_SPACE (target))
          && !TYPE_READONLY (target))
        {
          /* Pointers to non-generic address space must be const.  */
          
          return TYPE_ADDR_SPACE (target);
        }

      /* Scan pointer's target type.  */
      
      return avr_nonconst_pointer_addrspace (target);
    }

  return ADDR_SPACE_GENERIC;
}


/* Sanity check NODE so that all pointers targeting non-generic addres spaces
   go along with CONST qualifier.  Writing to these address spaces should
   be detected and complained about as early as possible.  */

static bool
avr_pgm_check_var_decl (tree node)
{
  const char *reason = NULL;
  
  addr_space_t as = ADDR_SPACE_GENERIC;

  gcc_assert (as == 0);
  
  if (avr_log.progmem)
    avr_edump ("%?: %t\n", node);
  
  switch (TREE_CODE (node))
    {
    default:
      break;

    case VAR_DECL:
      if (as = avr_nonconst_pointer_addrspace (TREE_TYPE (node)), as)
        reason = "variable";
      break;

    case PARM_DECL:
      if (as = avr_nonconst_pointer_addrspace (TREE_TYPE (node)), as)
        reason = "function parameter";
      break;
        
    case FIELD_DECL:
      if (as = avr_nonconst_pointer_addrspace (TREE_TYPE (node)), as)
        reason = "structure field";
      break;
        
    case FUNCTION_DECL:
      if (as = avr_nonconst_pointer_addrspace (TREE_TYPE (TREE_TYPE (node))),
          as)
        reason = "return type of function";
      break;

    case POINTER_TYPE:
      if (as = avr_nonconst_pointer_addrspace (node), as)
        reason = "pointer";
      break;
    }

  if (reason)
    {
      if (TYPE_P (node))
        error ("pointer targeting address space %qs must be const in %qT",
               avr_addrspace[as].name, node);
      else
        error ("pointer targeting address space %qs must be const in %s %q+D",
               avr_addrspace[as].name, reason, node);
    }

  return reason == NULL;
}


/* Add the section attribute if the variable is in progmem.  */

static void
avr_insert_attributes (tree node, tree *attributes)
{
  avr_pgm_check_var_decl (node);

  if (TREE_CODE (node) == VAR_DECL
      && (TREE_STATIC (node) || DECL_EXTERNAL (node))
      && avr_progmem_p (node, *attributes))
    {
      tree node0 = node;

      /* For C++, we have to peel arrays in order to get correct
         determination of readonlyness.  */
      
      do
        node0 = TREE_TYPE (node0);
      while (TREE_CODE (node0) == ARRAY_TYPE);

      if (error_mark_node == node0)
        return;
      
      if (!TYPE_READONLY (node0)
          && !TREE_READONLY (node))
        {
          addr_space_t as = TYPE_ADDR_SPACE (TREE_TYPE (node));
          const char *reason = "__attribute__((progmem))";

          if (!ADDR_SPACE_GENERIC_P (as))
            reason = avr_addrspace[as].name;
          
          if (avr_log.progmem)
            avr_edump ("\n%?: %t\n%t\n", node, node0);
          
          error ("variable %q+D must be const in order to be put into"
                 " read-only section by means of %qs", node, reason);
        }
    }
}


/* Implement `ASM_OUTPUT_ALIGNED_DECL_LOCAL'.  */
/* Implement `ASM_OUTPUT_ALIGNED_DECL_COMMON'.  */
/* Track need of __do_clear_bss.  */

void
avr_asm_output_aligned_decl_common (FILE * stream,
                                    const_tree decl ATTRIBUTE_UNUSED,
                                    const char *name,
                                    unsigned HOST_WIDE_INT size,
                                    unsigned int align, bool local_p)
{
  /* __gnu_lto_v1 etc. are just markers for the linker injected by toplev.c.
     There is no need to trigger __do_clear_bss code for them.  */

  if (!STR_PREFIX_P (name, "__gnu_lto"))
    avr_need_clear_bss_p = true;

  if (local_p)
    ASM_OUTPUT_ALIGNED_LOCAL (stream, name, size, align);
  else
    ASM_OUTPUT_ALIGNED_COMMON (stream, name, size, align);
}


/* Unnamed section callback for data_section
   to track need of __do_copy_data.  */

static void
avr_output_data_section_asm_op (const void *data)
{
  avr_need_copy_data_p = true;
  
  /* Dispatch to default.  */
  output_section_asm_op (data);
}


/* Unnamed section callback for bss_section
   to track need of __do_clear_bss.  */

static void
avr_output_bss_section_asm_op (const void *data)
{
  avr_need_clear_bss_p = true;
  
  /* Dispatch to default.  */
  output_section_asm_op (data);
}


/* Unnamed section callback for progmem*.data sections.  */

static void
avr_output_progmem_section_asm_op (const void *data)
{
  fprintf (asm_out_file, "\t.section\t%s,\"a\",@progbits\n",
           (const char*) data);
}


/* Implement `TARGET_ASM_INIT_SECTIONS'.  */

static void
avr_asm_init_sections (void)
{
  unsigned int n;
  
  /* Set up a section for jump tables.  Alignment is handled by
     ASM_OUTPUT_BEFORE_CASE_LABEL.  */
  
  if (AVR_HAVE_JMP_CALL)
    {
      progmem_swtable_section
        = get_unnamed_section (0, output_section_asm_op,
                               "\t.section\t.progmem.gcc_sw_table"
                               ",\"a\",@progbits");
    }
  else
    {
      progmem_swtable_section
        = get_unnamed_section (SECTION_CODE, output_section_asm_op,
                               "\t.section\t.progmem.gcc_sw_table"
                               ",\"ax\",@progbits");
    }

  for (n = 0; n < sizeof (progmem_section) / sizeof (*progmem_section); n++)
    {
      progmem_section[n]
        = get_unnamed_section (0, avr_output_progmem_section_asm_op,
                               progmem_section_prefix[n]);
    }
  
  /* Override section callbacks to keep track of `avr_need_clear_bss_p'
     resp. `avr_need_copy_data_p'.  */
  
  readonly_data_section->unnamed.callback = avr_output_data_section_asm_op;
  data_section->unnamed.callback = avr_output_data_section_asm_op;
  bss_section->unnamed.callback = avr_output_bss_section_asm_op;
}


/* Implement `TARGET_ASM_FUNCTION_RODATA_SECTION'.  */

static section*
avr_asm_function_rodata_section (tree decl)
{
  /* If a function is unused and optimized out by -ffunction-sections
     and --gc-sections, ensure that the same will happen for its jump
     tables by putting them into individual sections.  */

  unsigned int flags;
  section * frodata;

  /* Get the frodata section from the default function in varasm.c
     but treat function-associated data-like jump tables as code
     rather than as user defined data.  AVR has no constant pools.  */
  {
    int fdata = flag_data_sections;

    flag_data_sections = flag_function_sections;
    frodata = default_function_rodata_section (decl);
    flag_data_sections = fdata;
    flags = frodata->common.flags;
  }

  if (frodata != readonly_data_section
      && flags & SECTION_NAMED)
    {
      /* Adjust section flags and replace section name prefix.  */

      unsigned int i;

      static const char* const prefix[] =
        {
          ".rodata",          ".progmem.gcc_sw_table",
          ".gnu.linkonce.r.", ".gnu.linkonce.t."
        };

      for (i = 0; i < sizeof (prefix) / sizeof (*prefix); i += 2)
        {
          const char * old_prefix = prefix[i];
          const char * new_prefix = prefix[i+1];
          const char * name = frodata->named.name;

          if (STR_PREFIX_P (name, old_prefix))
            {
              const char *rname = ACONCAT ((new_prefix,
                                            name + strlen (old_prefix), NULL));
              flags &= ~SECTION_CODE;
              flags |= AVR_HAVE_JMP_CALL ? 0 : SECTION_CODE;
              
              return get_section (rname, flags, frodata->named.decl);
            }
        }
    }
        
  return progmem_swtable_section;
}


/* Implement `TARGET_ASM_NAMED_SECTION'.  */
/* Track need of __do_clear_bss, __do_copy_data for named sections.  */

static void
avr_asm_named_section (const char *name, unsigned int flags, tree decl)
{
  if (flags & AVR_SECTION_PROGMEM)
    {
      addr_space_t as = (flags & AVR_SECTION_PROGMEM) / SECTION_MACH_DEP;
      int segment = avr_addrspace[as].segment % avr_current_arch->n_segments;
      const char *old_prefix = ".rodata";
      const char *new_prefix = progmem_section_prefix[segment];
      
      if (STR_PREFIX_P (name, old_prefix))
        {
          const char *sname = ACONCAT ((new_prefix,
                                        name + strlen (old_prefix), NULL));
          default_elf_asm_named_section (sname, flags, decl);
          return;
        }

      default_elf_asm_named_section (new_prefix, flags, decl);
      return;
    }
  
  if (!avr_need_copy_data_p)
    avr_need_copy_data_p = (STR_PREFIX_P (name, ".data")
                            || STR_PREFIX_P (name, ".rodata")
                            || STR_PREFIX_P (name, ".gnu.linkonce.d"));
  
  if (!avr_need_clear_bss_p)
    avr_need_clear_bss_p = STR_PREFIX_P (name, ".bss");
  
  default_elf_asm_named_section (name, flags, decl);
}

static unsigned int
avr_section_type_flags (tree decl, const char *name, int reloc)
{
  unsigned int flags = default_section_type_flags (decl, name, reloc);

  if (STR_PREFIX_P (name, ".noinit"))
    {
      if (decl && TREE_CODE (decl) == VAR_DECL
          && DECL_INITIAL (decl) == NULL_TREE)
        flags |= SECTION_BSS;  /* @nobits */
      else
        warning (0, "only uninitialized variables can be placed in the "
                 ".noinit section");
    }

  if (decl && DECL_P (decl)
      && avr_progmem_p (decl, DECL_ATTRIBUTES (decl)))
    {
      addr_space_t as = TYPE_ADDR_SPACE (TREE_TYPE (decl));

      /* Attribute progmem puts data in generic address space.
         Set section flags as if it was in __flash to get the right
         section prefix in the remainder.  */

      if (ADDR_SPACE_GENERIC_P (as))
        as = ADDR_SPACE_FLASH;

      flags |= as * SECTION_MACH_DEP;
      flags &= ~SECTION_WRITE;
      flags &= ~SECTION_BSS;
    }
  
  return flags;
}


/* Implement `TARGET_ENCODE_SECTION_INFO'.  */

static void
avr_encode_section_info (tree decl, rtx rtl, int new_decl_p)
{
  /* In avr_handle_progmem_attribute, DECL_INITIAL is not yet
     readily available, see PR34734.  So we postpone the warning
     about uninitialized data in program memory section until here.  */
   
  if (new_decl_p
      && decl && DECL_P (decl)
      && NULL_TREE == DECL_INITIAL (decl)
      && !DECL_EXTERNAL (decl)
      && avr_progmem_p (decl, DECL_ATTRIBUTES (decl)))
    {
      warning (OPT_Wuninitialized,
               "uninitialized variable %q+D put into "
               "program memory area", decl);
    }

  default_encode_section_info (decl, rtl, new_decl_p);

  if (decl && DECL_P (decl)
      && TREE_CODE (decl) != FUNCTION_DECL
      && MEM_P (rtl)
      && SYMBOL_REF == GET_CODE (XEXP (rtl, 0)))
   {
      rtx sym = XEXP (rtl, 0);
      addr_space_t as = TYPE_ADDR_SPACE (TREE_TYPE (decl));

      /* PSTR strings are in generic space but located in flash:
         patch address space.  */
      
      if (-1 == avr_progmem_p (decl, DECL_ATTRIBUTES (decl)))
        as = ADDR_SPACE_FLASH;

      AVR_SYMBOL_SET_ADDR_SPACE (sym, as);
    }
}


/* Implement `TARGET_ASM_SELECT_SECTION' */

static section *
avr_asm_select_section (tree decl, int reloc, unsigned HOST_WIDE_INT align)
{
  section * sect = default_elf_select_section (decl, reloc, align);
  
  if (decl && DECL_P (decl)
      && avr_progmem_p (decl, DECL_ATTRIBUTES (decl)))
    {
      addr_space_t as = TYPE_ADDR_SPACE (TREE_TYPE (decl));
      int segment = avr_addrspace[as].segment % avr_current_arch->n_segments;
      
      if (sect->common.flags & SECTION_NAMED)
        {
          const char * name = sect->named.name;
          const char * old_prefix = ".rodata";
          const char * new_prefix = progmem_section_prefix[segment];

          if (STR_PREFIX_P (name, old_prefix))
            {
              const char *sname = ACONCAT ((new_prefix,
                                            name + strlen (old_prefix), NULL));
              return get_section (sname, sect->common.flags, sect->named.decl);
            }
        }
          
      return progmem_section[segment];
    }

  return sect;
}

/* Implement `TARGET_ASM_FILE_START'.  */
/* Outputs some text at the start of each assembler file.  */

static void
avr_file_start (void)
{
  int sfr_offset = avr_current_arch->sfr_offset;

  if (avr_current_arch->asm_only)
    error ("MCU %qs supported for assembler only", avr_current_device->name);

  default_file_start ();

  /* Print I/O addresses of some SFRs used with IN and OUT.  */

  if (!AVR_HAVE_8BIT_SP)
    fprintf (asm_out_file, "__SP_H__ = 0x%02x\n", avr_addr.sp_h - sfr_offset);

  fprintf (asm_out_file, "__SP_L__ = 0x%02x\n", avr_addr.sp_l - sfr_offset);
  fprintf (asm_out_file, "__SREG__ = 0x%02x\n", avr_addr.sreg - sfr_offset);
  if (AVR_HAVE_RAMPZ)
    fprintf (asm_out_file, "__RAMPZ__ = 0x%02x\n", avr_addr.rampz - sfr_offset);
  if (AVR_HAVE_RAMPY)
    fprintf (asm_out_file, "__RAMPY__ = 0x%02x\n", avr_addr.rampy - sfr_offset);
  if (AVR_HAVE_RAMPX)
    fprintf (asm_out_file, "__RAMPX__ = 0x%02x\n", avr_addr.rampx - sfr_offset);
  if (AVR_HAVE_RAMPD)
    fprintf (asm_out_file, "__RAMPD__ = 0x%02x\n", avr_addr.rampd - sfr_offset);
  if (AVR_XMEGA)
    fprintf (asm_out_file, "__CCP__ = 0x%02x\n", avr_addr.ccp - sfr_offset);
  fprintf (asm_out_file, "__tmp_reg__ = %d\n", TMP_REGNO);
  fprintf (asm_out_file, "__zero_reg__ = %d\n", ZERO_REGNO);
}


/* Implement `TARGET_ASM_FILE_END'.  */
/* Outputs to the stdio stream FILE some
   appropriate text to go at the end of an assembler file.  */

static void
avr_file_end (void)
{
  /* Output these only if there is anything in the
     .data* / .rodata* / .gnu.linkonce.* resp. .bss*
     input section(s) - some code size can be saved by not
     linking in the initialization code from libgcc if resp.
     sections are empty.  */

  if (avr_need_copy_data_p)
    fputs (".global __do_copy_data\n", asm_out_file);

  if (avr_need_clear_bss_p)
    fputs (".global __do_clear_bss\n", asm_out_file);
}

/* Choose the order in which to allocate hard registers for
   pseudo-registers local to a basic block.

   Store the desired register order in the array `reg_alloc_order'.
   Element 0 should be the register to allocate first; element 1, the
   next register; and so on.  */

void
order_regs_for_local_alloc (void)
{
  unsigned int i;
  static const int order_0[] = {
    24,25,
    18,19,
    20,21,
    22,23,
    30,31,
    26,27,
    28,29,
    17,16,15,14,13,12,11,10,9,8,7,6,5,4,3,2,
    0,1,
    32,33,34,35
  };
  static const int order_1[] = {
    18,19,
    20,21,
    22,23,
    24,25,
    30,31,
    26,27,
    28,29,
    17,16,15,14,13,12,11,10,9,8,7,6,5,4,3,2,
    0,1,
    32,33,34,35
  };
  static const int order_2[] = {
    25,24,
    23,22,
    21,20,
    19,18,
    30,31,
    26,27,
    28,29,
    17,16,
    15,14,13,12,11,10,9,8,7,6,5,4,3,2,
    1,0,
    32,33,34,35
  };
  
  const int *order = (TARGET_ORDER_1 ? order_1 :
                      TARGET_ORDER_2 ? order_2 :
                      order_0);
  for (i=0; i < ARRAY_SIZE (order_0); ++i)
      reg_alloc_order[i] = order[i];
}


/* Implement `TARGET_REGISTER_MOVE_COST' */

static int
avr_register_move_cost (enum machine_mode mode ATTRIBUTE_UNUSED,
                        reg_class_t from, reg_class_t to)
{
  return (from == STACK_REG ? 6
          : to == STACK_REG ? 12
          : 2);
}


/* Implement `TARGET_MEMORY_MOVE_COST' */

static int
avr_memory_move_cost (enum machine_mode mode,
                      reg_class_t rclass ATTRIBUTE_UNUSED,
                      bool in ATTRIBUTE_UNUSED)
{
  return (mode == QImode ? 2
          : mode == HImode ? 4
          : mode == SImode ? 8
          : mode == SFmode ? 8
          : 16);
}


/* Mutually recursive subroutine of avr_rtx_cost for calculating the
   cost of an RTX operand given its context.  X is the rtx of the
   operand, MODE is its mode, and OUTER is the rtx_code of this
   operand's parent operator.  */

static int
avr_operand_rtx_cost (rtx x, enum machine_mode mode, enum rtx_code outer,
                      int opno, bool speed)
{
  enum rtx_code code = GET_CODE (x);
  int total;

  switch (code)
    {
    case REG:
    case SUBREG:
      return 0;

    case CONST_INT:
    case CONST_DOUBLE:
      return COSTS_N_INSNS (GET_MODE_SIZE (mode));

    default:
      break;
    }

  total = 0;
  avr_rtx_costs (x, code, outer, opno, &total, speed);
  return total;
}

/* Worker function for AVR backend's rtx_cost function.
   X is rtx expression whose cost is to be calculated.
   Return true if the complete cost has been computed.
   Return false if subexpressions should be scanned.
   In either case, *TOTAL contains the cost result.  */

static bool
avr_rtx_costs_1 (rtx x, int codearg, int outer_code ATTRIBUTE_UNUSED,
                 int opno ATTRIBUTE_UNUSED, int *total, bool speed)
{
  enum rtx_code code = (enum rtx_code) codearg;
  enum machine_mode mode = GET_MODE (x);
  HOST_WIDE_INT val;

  switch (code)
    {
    case CONST_INT:
    case CONST_DOUBLE:
    case SYMBOL_REF:
    case CONST:
    case LABEL_REF:
      /* Immediate constants are as cheap as registers.  */
      *total = 0;
      return true;

    case MEM:
      *total = COSTS_N_INSNS (GET_MODE_SIZE (mode));
      return true;

    case NEG:
      switch (mode)
        {
        case QImode:
        case SFmode:
          *total = COSTS_N_INSNS (1);
          break;

        case HImode:
        case PSImode:
        case SImode:
          *total = COSTS_N_INSNS (2 * GET_MODE_SIZE (mode) - 1);
          break;

        default:
          return false;
        }
      *total += avr_operand_rtx_cost (XEXP (x, 0), mode, code, 0, speed);
      return true;

    case ABS:
      switch (mode)
        {
        case QImode:
        case SFmode:
          *total = COSTS_N_INSNS (1);
          break;

        default:
          return false;
        }
      *total += avr_operand_rtx_cost (XEXP (x, 0), mode, code, 0, speed);
      return true;

    case NOT:
      *total = COSTS_N_INSNS (GET_MODE_SIZE (mode));
      *total += avr_operand_rtx_cost (XEXP (x, 0), mode, code, 0, speed);
      return true;

    case ZERO_EXTEND:
      *total = COSTS_N_INSNS (GET_MODE_SIZE (mode)
                              - GET_MODE_SIZE (GET_MODE (XEXP (x, 0))));
      *total += avr_operand_rtx_cost (XEXP (x, 0), mode, code, 0, speed);
      return true;

    case SIGN_EXTEND:
      *total = COSTS_N_INSNS (GET_MODE_SIZE (mode) + 2
                              - GET_MODE_SIZE (GET_MODE (XEXP (x, 0))));
      *total += avr_operand_rtx_cost (XEXP (x, 0), mode, code, 0, speed);
      return true;

    case PLUS:
      switch (mode)
        {
        case QImode:
          if (AVR_HAVE_MUL
              && MULT == GET_CODE (XEXP (x, 0))
              && register_operand (XEXP (x, 1), QImode))
            {
              /* multiply-add */
              *total = COSTS_N_INSNS (speed ? 4 : 3);
              /* multiply-add with constant: will be split and load constant. */
              if (CONST_INT_P (XEXP (XEXP (x, 0), 1)))
                *total = COSTS_N_INSNS (1) + *total;
              return true;
            }
          *total = COSTS_N_INSNS (1);
          if (GET_CODE (XEXP (x, 1)) != CONST_INT)
            *total += avr_operand_rtx_cost (XEXP (x, 1), mode, code, 1, speed);
          break;

        case HImode:
          if (AVR_HAVE_MUL
              && (MULT == GET_CODE (XEXP (x, 0))
                  || ASHIFT == GET_CODE (XEXP (x, 0)))
              && register_operand (XEXP (x, 1), HImode)
              && (ZERO_EXTEND == GET_CODE (XEXP (XEXP (x, 0), 0))
                  || SIGN_EXTEND == GET_CODE (XEXP (XEXP (x, 0), 0))))
            {
              /* multiply-add */
              *total = COSTS_N_INSNS (speed ? 5 : 4);
              /* multiply-add with constant: will be split and load constant. */
              if (CONST_INT_P (XEXP (XEXP (x, 0), 1)))
                *total = COSTS_N_INSNS (1) + *total;
              return true;
            }
          if (GET_CODE (XEXP (x, 1)) != CONST_INT)
            {
              *total = COSTS_N_INSNS (2);
              *total += avr_operand_rtx_cost (XEXP (x, 1), mode, code, 1,
                                              speed);
            }
          else if (INTVAL (XEXP (x, 1)) >= -63 && INTVAL (XEXP (x, 1)) <= 63)
            *total = COSTS_N_INSNS (1);
          else
            *total = COSTS_N_INSNS (2);
          break;

        case PSImode:
          if (!CONST_INT_P (XEXP (x, 1)))
            {
              *total = COSTS_N_INSNS (3);
              *total += avr_operand_rtx_cost (XEXP (x, 1), mode, code, 1,
                                              speed);
            }
          else if (INTVAL (XEXP (x, 1)) >= -63 && INTVAL (XEXP (x, 1)) <= 63)
            *total = COSTS_N_INSNS (2);
          else
            *total = COSTS_N_INSNS (3);
          break;

        case SImode:
          if (GET_CODE (XEXP (x, 1)) != CONST_INT)
            {
              *total = COSTS_N_INSNS (4);
              *total += avr_operand_rtx_cost (XEXP (x, 1), mode, code, 1,
                                              speed);
            }
          else if (INTVAL (XEXP (x, 1)) >= -63 && INTVAL (XEXP (x, 1)) <= 63)
            *total = COSTS_N_INSNS (1);
          else
            *total = COSTS_N_INSNS (4);
          break;

        default:
          return false;
        }
      *total += avr_operand_rtx_cost (XEXP (x, 0), mode, code, 0, speed);
      return true;

    case MINUS:
      if (AVR_HAVE_MUL
          && QImode == mode
          && register_operand (XEXP (x, 0), QImode)
          && MULT == GET_CODE (XEXP (x, 1)))
        {
          /* multiply-sub */
          *total = COSTS_N_INSNS (speed ? 4 : 3);
          /* multiply-sub with constant: will be split and load constant. */
          if (CONST_INT_P (XEXP (XEXP (x, 1), 1)))
            *total = COSTS_N_INSNS (1) + *total;
          return true;
        }
      if (AVR_HAVE_MUL
          && HImode == mode
          && register_operand (XEXP (x, 0), HImode)
          && (MULT == GET_CODE (XEXP (x, 1))
              || ASHIFT == GET_CODE (XEXP (x, 1)))
          && (ZERO_EXTEND == GET_CODE (XEXP (XEXP (x, 1), 0))
              || SIGN_EXTEND == GET_CODE (XEXP (XEXP (x, 1), 0))))
        {
          /* multiply-sub */
          *total = COSTS_N_INSNS (speed ? 5 : 4);
          /* multiply-sub with constant: will be split and load constant. */
          if (CONST_INT_P (XEXP (XEXP (x, 1), 1)))
            *total = COSTS_N_INSNS (1) + *total;
          return true;
        }
      /* FALLTHRU */
    case AND:
    case IOR:
      *total = COSTS_N_INSNS (GET_MODE_SIZE (mode));
      *total += avr_operand_rtx_cost (XEXP (x, 0), mode, code, 0, speed);
      if (GET_CODE (XEXP (x, 1)) != CONST_INT)
        *total += avr_operand_rtx_cost (XEXP (x, 1), mode, code, 1, speed);
      return true;

    case XOR:
      *total = COSTS_N_INSNS (GET_MODE_SIZE (mode));
      *total += avr_operand_rtx_cost (XEXP (x, 0), mode, code, 0, speed);
      *total += avr_operand_rtx_cost (XEXP (x, 1), mode, code, 1, speed);
      return true;

    case MULT:
      switch (mode)
        {
        case QImode:
          if (AVR_HAVE_MUL)
            *total = COSTS_N_INSNS (!speed ? 3 : 4);
          else if (!speed)
            *total = COSTS_N_INSNS (AVR_HAVE_JMP_CALL ? 2 : 1);
          else
            return false;
          break;

        case HImode:
          if (AVR_HAVE_MUL)
            {
              rtx op0 = XEXP (x, 0);
              rtx op1 = XEXP (x, 1);
              enum rtx_code code0 = GET_CODE (op0);
              enum rtx_code code1 = GET_CODE (op1);
              bool ex0 = SIGN_EXTEND == code0 || ZERO_EXTEND == code0;
              bool ex1 = SIGN_EXTEND == code1 || ZERO_EXTEND == code1;

              if (ex0
                  && (u8_operand (op1, HImode)
                      || s8_operand (op1, HImode)))
                {
                  *total = COSTS_N_INSNS (!speed ? 4 : 6);
                  return true;
                }
              if (ex0
                  && register_operand (op1, HImode))
                {
                  *total = COSTS_N_INSNS (!speed ? 5 : 8);
                  return true;
                }
              else if (ex0 || ex1)
                {
                  *total = COSTS_N_INSNS (!speed ? 3 : 5);
                  return true;
                }
              else if (register_operand (op0, HImode)
                       && (u8_operand (op1, HImode)
                           || s8_operand (op1, HImode)))
                {
                  *total = COSTS_N_INSNS (!speed ? 6 : 9);
                  return true;
                }
              else
                *total = COSTS_N_INSNS (!speed ? 7 : 10);
            }
          else if (!speed)
            *total = COSTS_N_INSNS (AVR_HAVE_JMP_CALL ? 2 : 1);
          else
            return false;
          break;

        case PSImode:
          if (!speed)
            *total = COSTS_N_INSNS (AVR_HAVE_JMP_CALL ? 2 : 1);
          else
            *total = 10;
          break;

        case SImode:
          if (AVR_HAVE_MUL)
            {
              if (!speed)
                {
                  /* Add some additional costs besides CALL like moves etc.  */

                  *total = COSTS_N_INSNS (AVR_HAVE_JMP_CALL ? 5 : 4);
                }
              else
                {
                  /* Just a rough estimate.  Even with -O2 we don't want bulky
                     code expanded inline.  */

                  *total = COSTS_N_INSNS (25);
                }
            }
          else
            {
              if (speed)
                *total = COSTS_N_INSNS (300);
              else
                /* Add some additional costs besides CALL like moves etc.  */
                *total = COSTS_N_INSNS (AVR_HAVE_JMP_CALL ? 5 : 4);
            }
          
          return true;
          
        default:
          return false;
        }
      *total += avr_operand_rtx_cost (XEXP (x, 0), mode, code, 0, speed);
      *total += avr_operand_rtx_cost (XEXP (x, 1), mode, code, 1, speed);
      return true;

    case DIV:
    case MOD:
    case UDIV:
    case UMOD:
      if (!speed)
        *total = COSTS_N_INSNS (AVR_HAVE_JMP_CALL ? 2 : 1);
      else
        *total = COSTS_N_INSNS (15 * GET_MODE_SIZE (mode));
      *total += avr_operand_rtx_cost (XEXP (x, 0), mode, code, 0, speed);
      /* For div/mod with const-int divisor we have at least the cost of
         loading the divisor. */
      if (CONST_INT_P (XEXP (x, 1)))
        *total += COSTS_N_INSNS (GET_MODE_SIZE (mode));
      /* Add some overall penaly for clobbering and moving around registers */
      *total += COSTS_N_INSNS (2);
      return true;

    case ROTATE:
      switch (mode)
        {
        case QImode:
          if (CONST_INT_P (XEXP (x, 1)) && INTVAL (XEXP (x, 1)) == 4)
            *total = COSTS_N_INSNS (1);

          break;

        case HImode:
          if (CONST_INT_P (XEXP (x, 1)) && INTVAL (XEXP (x, 1)) == 8)
            *total = COSTS_N_INSNS (3);

          break;

        case SImode:
          if (CONST_INT_P (XEXP (x, 1)))
            switch (INTVAL (XEXP (x, 1)))
              {
              case 8:
              case 24:
                *total = COSTS_N_INSNS (5);
                break;
              case 16:
                *total = COSTS_N_INSNS (AVR_HAVE_MOVW ? 4 : 6);
                break;
              }
          break;

        default:
          return false;
        }
      *total += avr_operand_rtx_cost (XEXP (x, 0), mode, code, 0, speed);
      return true;    

    case ASHIFT:
      switch (mode)
        {
        case QImode:
          if (GET_CODE (XEXP (x, 1)) != CONST_INT)
            {
              *total = COSTS_N_INSNS (!speed ? 4 : 17);
              *total += avr_operand_rtx_cost (XEXP (x, 1), mode, code, 1,
                                              speed);
            }
          else
            {
              val = INTVAL (XEXP (x, 1));
              if (val == 7)
                *total = COSTS_N_INSNS (3);
              else if (val >= 0 && val <= 7)
                *total = COSTS_N_INSNS (val);
              else
                *total = COSTS_N_INSNS (1);
            }
          break;

        case HImode:
          if (AVR_HAVE_MUL)
            {
              if (const_2_to_7_operand (XEXP (x, 1), HImode)
                  && (SIGN_EXTEND == GET_CODE (XEXP (x, 0))
                      || ZERO_EXTEND == GET_CODE (XEXP (x, 0))))
                {
                  *total = COSTS_N_INSNS (!speed ? 4 : 6);
                  return true;
                }
            }
          
          if (const1_rtx == (XEXP (x, 1))
              && SIGN_EXTEND == GET_CODE (XEXP (x, 0)))
            {
              *total = COSTS_N_INSNS (2);
              return true;
            }
          
          if (GET_CODE (XEXP (x, 1)) != CONST_INT)
            {
              *total = COSTS_N_INSNS (!speed ? 5 : 41);
              *total += avr_operand_rtx_cost (XEXP (x, 1), mode, code, 1,
                                              speed);
            }
          else
            switch (INTVAL (XEXP (x, 1)))
              {
              case 0:
                *total = 0;
                break;
              case 1:
              case 8:
                *total = COSTS_N_INSNS (2);
                break;
              case 9:
                *total = COSTS_N_INSNS (3);
                break;
              case 2:
              case 3:
              case 10:
              case 15:
                *total = COSTS_N_INSNS (4);
                break;
              case 7:
              case 11:
              case 12:
                *total = COSTS_N_INSNS (5);
                break;
              case 4:
                *total = COSTS_N_INSNS (!speed ? 5 : 8);
                break;
              case 6:
                *total = COSTS_N_INSNS (!speed ? 5 : 9);
                break;
              case 5:
                *total = COSTS_N_INSNS (!speed ? 5 : 10);
                break;
              default:
                *total = COSTS_N_INSNS (!speed ? 5 : 41);
                *total += avr_operand_rtx_cost (XEXP (x, 1), mode, code, 1,
                                                speed);
              }
          break;

        case PSImode:
          if (!CONST_INT_P (XEXP (x, 1)))
            {
              *total = COSTS_N_INSNS (!speed ? 6 : 73);
            }
          else
            switch (INTVAL (XEXP (x, 1)))
              {
              case 0:
                *total = 0;
                break;
              case 1:
              case 8:
              case 16:
                *total = COSTS_N_INSNS (3);
                break;
              case 23:
                *total = COSTS_N_INSNS (5);
                break;
              default:
                *total = COSTS_N_INSNS (!speed ? 5 : 3 * INTVAL (XEXP (x, 1)));
                break;
              }
          break;

        case SImode:
          if (GET_CODE (XEXP (x, 1)) != CONST_INT)
            {
              *total = COSTS_N_INSNS (!speed ? 7 : 113);
              *total += avr_operand_rtx_cost (XEXP (x, 1), mode, code, 1,
                                              speed);
            }
          else
            switch (INTVAL (XEXP (x, 1)))
              {
              case 0:
                *total = 0;
                break;
              case 24:
                *total = COSTS_N_INSNS (3);
                break;
              case 1:
              case 8:
              case 16:
                *total = COSTS_N_INSNS (4);
                break;
              case 31:
                *total = COSTS_N_INSNS (6);
                break;
              case 2:
                *total = COSTS_N_INSNS (!speed ? 7 : 8);
                break;
              default:
                *total = COSTS_N_INSNS (!speed ? 7 : 113);
                *total += avr_operand_rtx_cost (XEXP (x, 1), mode, code, 1,
                                                speed);
              }
          break;

        default:
          return false;
        }
      *total += avr_operand_rtx_cost (XEXP (x, 0), mode, code, 0, speed);
      return true;

    case ASHIFTRT:
      switch (mode)
        {
        case QImode:
          if (GET_CODE (XEXP (x, 1)) != CONST_INT)
            {
              *total = COSTS_N_INSNS (!speed ? 4 : 17);
              *total += avr_operand_rtx_cost (XEXP (x, 1), mode, code, 1,
                                              speed);
            }
          else
            {
              val = INTVAL (XEXP (x, 1));
              if (val == 6)
                *total = COSTS_N_INSNS (4);
              else if (val == 7)
                *total = COSTS_N_INSNS (2);
              else if (val >= 0 && val <= 7)
                *total = COSTS_N_INSNS (val);
              else
                *total = COSTS_N_INSNS (1);
            }
          break;

        case HImode:
          if (GET_CODE (XEXP (x, 1)) != CONST_INT)
            {
              *total = COSTS_N_INSNS (!speed ? 5 : 41);
              *total += avr_operand_rtx_cost (XEXP (x, 1), mode, code, 1,
                                              speed);
            }
          else
            switch (INTVAL (XEXP (x, 1)))
              {
              case 0:
                *total = 0;
                break;
              case 1:
                *total = COSTS_N_INSNS (2);
                break;
              case 15:
                *total = COSTS_N_INSNS (3);
                break;
              case 2:
              case 7:
              case 8:
              case 9:
                *total = COSTS_N_INSNS (4);
                break;
              case 10:
              case 14:
                *total = COSTS_N_INSNS (5);
                break;
              case 11:
                *total = COSTS_N_INSNS (!speed ? 5 : 6);
                break;
              case 12:
                *total = COSTS_N_INSNS (!speed ? 5 : 7);
                break;
              case 6:
              case 13:
                *total = COSTS_N_INSNS (!speed ? 5 : 8);
                break;
              default:
                *total = COSTS_N_INSNS (!speed ? 5 : 41);
                *total += avr_operand_rtx_cost (XEXP (x, 1), mode, code, 1,
                                                speed);
              }
          break;

        case PSImode:
          if (!CONST_INT_P (XEXP (x, 1)))
            {
              *total = COSTS_N_INSNS (!speed ? 6 : 73);
            }
          else
            switch (INTVAL (XEXP (x, 1)))
              {
              case 0:
                *total = 0;
                break;
              case 1:
                *total = COSTS_N_INSNS (3);
                break;
              case 16:
              case 8:
                *total = COSTS_N_INSNS (5);
                break;
              case 23:
                *total = COSTS_N_INSNS (4);
                break;
              default:
                *total = COSTS_N_INSNS (!speed ? 5 : 3 * INTVAL (XEXP (x, 1)));
                break;
              }
          break;

        case SImode:
          if (GET_CODE (XEXP (x, 1)) != CONST_INT)
            {
              *total = COSTS_N_INSNS (!speed ? 7 : 113);
              *total += avr_operand_rtx_cost (XEXP (x, 1), mode, code, 1,
                                              speed);
            }
          else
            switch (INTVAL (XEXP (x, 1)))
              {
              case 0:
                *total = 0;
                break;
              case 1:
                *total = COSTS_N_INSNS (4);
                break;
              case 8:
              case 16:
              case 24:
                *total = COSTS_N_INSNS (6);
                break;
              case 2:
                *total = COSTS_N_INSNS (!speed ? 7 : 8);
                break;
              case 31:
                *total = COSTS_N_INSNS (AVR_HAVE_MOVW ? 4 : 5);
                break;
              default:
                *total = COSTS_N_INSNS (!speed ? 7 : 113);
                *total += avr_operand_rtx_cost (XEXP (x, 1), mode, code, 1,
                                                speed);
              }
          break;

        default:
          return false;
        }
      *total += avr_operand_rtx_cost (XEXP (x, 0), mode, code, 0, speed);
      return true;

    case LSHIFTRT:
      switch (mode)
        {
        case QImode:
          if (GET_CODE (XEXP (x, 1)) != CONST_INT)
            {
              *total = COSTS_N_INSNS (!speed ? 4 : 17);
              *total += avr_operand_rtx_cost (XEXP (x, 1), mode, code, 1,
                                              speed);
            }
          else
            {
              val = INTVAL (XEXP (x, 1));
              if (val == 7)
                *total = COSTS_N_INSNS (3);
              else if (val >= 0 && val <= 7)
                *total = COSTS_N_INSNS (val);
              else
                *total = COSTS_N_INSNS (1);
            }
          break;

        case HImode:
          if (GET_CODE (XEXP (x, 1)) != CONST_INT)
            {
              *total = COSTS_N_INSNS (!speed ? 5 : 41);
              *total += avr_operand_rtx_cost (XEXP (x, 1), mode, code, 1,
                                              speed);
            }
          else
            switch (INTVAL (XEXP (x, 1)))
              {
              case 0:
                *total = 0;
                break;
              case 1:
              case 8:
                *total = COSTS_N_INSNS (2);
                break;
              case 9:
                *total = COSTS_N_INSNS (3);
                break;
              case 2:
              case 10:
              case 15:
                *total = COSTS_N_INSNS (4);
                break;
              case 7:
              case 11:
                *total = COSTS_N_INSNS (5);
                break;
              case 3:
              case 12:
              case 13:
              case 14:
                *total = COSTS_N_INSNS (!speed ? 5 : 6);
                break;
              case 4:
                *total = COSTS_N_INSNS (!speed ? 5 : 7);
                break;
              case 5:
              case 6:
                *total = COSTS_N_INSNS (!speed ? 5 : 9);
                break;
              default:
                *total = COSTS_N_INSNS (!speed ? 5 : 41);
                *total += avr_operand_rtx_cost (XEXP (x, 1), mode, code, 1,
                                                speed);
              }
          break;

        case PSImode:
          if (!CONST_INT_P (XEXP (x, 1)))
            {
              *total = COSTS_N_INSNS (!speed ? 6 : 73);
            }
          else
            switch (INTVAL (XEXP (x, 1)))
              {
              case 0:
                *total = 0;
                break;
              case 1:
              case 8:
              case 16:
                *total = COSTS_N_INSNS (3);
                break;
              case 23:
                *total = COSTS_N_INSNS (5);
                break;
              default:
                *total = COSTS_N_INSNS (!speed ? 5 : 3 * INTVAL (XEXP (x, 1)));
                break;
              }
          break;

        case SImode:
          if (GET_CODE (XEXP (x, 1)) != CONST_INT)
            {
              *total = COSTS_N_INSNS (!speed ? 7 : 113);
              *total += avr_operand_rtx_cost (XEXP (x, 1), mode, code, 1,
                                              speed);
            }
          else
            switch (INTVAL (XEXP (x, 1)))
              {
              case 0:
                *total = 0;
                break;
              case 1:
                *total = COSTS_N_INSNS (4);
                break;
              case 2:
                *total = COSTS_N_INSNS (!speed ? 7 : 8);
                break;
              case 8:
              case 16:
              case 24:
                *total = COSTS_N_INSNS (4);
                break;
              case 31:
                *total = COSTS_N_INSNS (6);
                break;
              default:
                *total = COSTS_N_INSNS (!speed ? 7 : 113);
                *total += avr_operand_rtx_cost (XEXP (x, 1), mode, code, 1,
                                                speed);
              }
          break;

        default:
          return false;
        }
      *total += avr_operand_rtx_cost (XEXP (x, 0), mode, code, 0, speed);
      return true;

    case COMPARE:
      switch (GET_MODE (XEXP (x, 0)))
        {
        case QImode:
          *total = COSTS_N_INSNS (1);
          if (GET_CODE (XEXP (x, 1)) != CONST_INT)
            *total += avr_operand_rtx_cost (XEXP (x, 1), mode, code, 1, speed);
          break;

        case HImode:
          *total = COSTS_N_INSNS (2);
          if (GET_CODE (XEXP (x, 1)) != CONST_INT)
            *total += avr_operand_rtx_cost (XEXP (x, 1), mode, code, 1, speed);
          else if (INTVAL (XEXP (x, 1)) != 0)
            *total += COSTS_N_INSNS (1);
          break;

        case PSImode:
          *total = COSTS_N_INSNS (3);
          if (CONST_INT_P (XEXP (x, 1)) && INTVAL (XEXP (x, 1)) != 0)
            *total += COSTS_N_INSNS (2);
          break;

        case SImode:
          *total = COSTS_N_INSNS (4);
          if (GET_CODE (XEXP (x, 1)) != CONST_INT)
            *total += avr_operand_rtx_cost (XEXP (x, 1), mode, code, 1, speed);
          else if (INTVAL (XEXP (x, 1)) != 0)
            *total += COSTS_N_INSNS (3);
          break;

        default:
          return false;
        }
      *total += avr_operand_rtx_cost (XEXP (x, 0), mode, code, 0, speed);
      return true;

    case TRUNCATE:
      if (AVR_HAVE_MUL
          && LSHIFTRT == GET_CODE (XEXP (x, 0))
          && MULT == GET_CODE (XEXP (XEXP (x, 0), 0))
          && CONST_INT_P (XEXP (XEXP (x, 0), 1)))
        {
          if (QImode == mode || HImode == mode)
            {
              *total = COSTS_N_INSNS (2);
              return true;
            }
        }
      break;

    default:
      break;
    }
  return false;
}


/* Implement `TARGET_RTX_COSTS'.  */

static bool
avr_rtx_costs (rtx x, int codearg, int outer_code,
               int opno, int *total, bool speed)
{
  bool done = avr_rtx_costs_1 (x, codearg, outer_code,
                               opno, total, speed);

  if (avr_log.rtx_costs)
    {
      avr_edump ("\n%?=%b (%s) total=%d, outer=%C:\n%r\n",
                 done, speed ? "speed" : "size", *total, outer_code, x);
    }

  return done;
}


/* Implement `TARGET_ADDRESS_COST'.  */

static int
avr_address_cost (rtx x, bool speed ATTRIBUTE_UNUSED)
{
  int cost = 4;
  
  if (GET_CODE (x) == PLUS
      && CONST_INT_P (XEXP (x, 1))
      && (REG_P (XEXP (x, 0))
          || GET_CODE (XEXP (x, 0)) == SUBREG))
    {
      if (INTVAL (XEXP (x, 1)) >= 61)
        cost = 18;
    }
  else if (CONSTANT_ADDRESS_P (x))
    {
      if (optimize > 0
          && io_address_operand (x, QImode))
        cost = 2;
    }

  if (avr_log.address_cost)
    avr_edump ("\n%?: %d = %r\n", cost, x);
  
  return cost;
}

/* Test for extra memory constraint 'Q'.
   It's a memory address based on Y or Z pointer with valid displacement.  */

int
extra_constraint_Q (rtx x)
{
  int ok = 0;
  
  if (GET_CODE (XEXP (x,0)) == PLUS
      && REG_P (XEXP (XEXP (x,0), 0))
      && GET_CODE (XEXP (XEXP (x,0), 1)) == CONST_INT
      && (INTVAL (XEXP (XEXP (x,0), 1))
          <= MAX_LD_OFFSET (GET_MODE (x))))
    {
      rtx xx = XEXP (XEXP (x,0), 0);
      int regno = REGNO (xx);
      
      ok = (/* allocate pseudos */
            regno >= FIRST_PSEUDO_REGISTER
            /* strictly check */
            || regno == REG_Z || regno == REG_Y
            /* XXX frame & arg pointer checks */
            || xx == frame_pointer_rtx
            || xx == arg_pointer_rtx);
      
      if (avr_log.constraints)
        avr_edump ("\n%?=%d reload_completed=%d reload_in_progress=%d\n %r\n",
                   ok, reload_completed, reload_in_progress, x);
    }

  return ok;
}

/* Convert condition code CONDITION to the valid AVR condition code.  */

RTX_CODE
avr_normalize_condition (RTX_CODE condition)
{
  switch (condition)
    {
    case GT:
      return GE;
    case GTU:
      return GEU;
    case LE:
      return LT;
    case LEU:
      return LTU;
    default:
      gcc_unreachable ();
    }
}

/* Helper function for `avr_reorg'.  */

static rtx
avr_compare_pattern (rtx insn)
{
  rtx pattern = single_set (insn);

  if (pattern
      && NONJUMP_INSN_P (insn)
      && SET_DEST (pattern) == cc0_rtx
      && GET_CODE (SET_SRC (pattern)) == COMPARE
      && DImode != GET_MODE (XEXP (SET_SRC (pattern), 0))
      && DImode != GET_MODE (XEXP (SET_SRC (pattern), 1)))
    {
      return pattern;
    }

  return NULL_RTX;
}

/* Helper function for `avr_reorg'.  */

/* Expansion of switch/case decision trees leads to code like

       cc0 = compare (Reg, Num)
       if (cc0 == 0)
         goto L1
         
       cc0 = compare (Reg, Num)
       if (cc0 > 0)
         goto L2

   The second comparison is superfluous and can be deleted.
   The second jump condition can be transformed from a
   "difficult" one to a "simple" one because "cc0 > 0" and
   "cc0 >= 0" will have the same effect here.

   This function relies on the way switch/case is being expaned
   as binary decision tree.  For example code see PR 49903.
         
   Return TRUE if optimization performed.
   Return FALSE if nothing changed.

   INSN1 is a comparison, i.e. avr_compare_pattern != 0.

   We don't want to do this in text peephole because it is
   tedious to work out jump offsets there and the second comparison
   might have been transormed by `avr_reorg'.

   RTL peephole won't do because peephole2 does not scan across
   basic blocks.  */                
                        
static bool
avr_reorg_remove_redundant_compare (rtx insn1)
{
  rtx comp1, ifelse1, xcond1, branch1;
  rtx comp2, ifelse2, xcond2, branch2, insn2;
  enum rtx_code code;
  rtx jump, target, cond;
  
  /* Look out for:  compare1 - branch1 - compare2 - branch2  */

  branch1 = next_nonnote_nondebug_insn (insn1);
  if (!branch1 || !JUMP_P (branch1))
    return false;

  insn2 = next_nonnote_nondebug_insn (branch1);
  if (!insn2 || !avr_compare_pattern (insn2))
    return false;

  branch2 = next_nonnote_nondebug_insn (insn2);
  if (!branch2 || !JUMP_P (branch2))
    return false;

  comp1 = avr_compare_pattern (insn1);
  comp2 = avr_compare_pattern (insn2);
  xcond1 = single_set (branch1);
  xcond2 = single_set (branch2);
  
  if (!comp1 || !comp2
      || !rtx_equal_p (comp1, comp2)
      || !xcond1 || SET_DEST (xcond1) != pc_rtx
      || !xcond2 || SET_DEST (xcond2) != pc_rtx
      || IF_THEN_ELSE != GET_CODE (SET_SRC (xcond1))
      || IF_THEN_ELSE != GET_CODE (SET_SRC (xcond2)))
    {
      return false;
    }

  comp1 = SET_SRC (comp1);
  ifelse1 = SET_SRC (xcond1);
  ifelse2 = SET_SRC (xcond2);

  /* comp<n> is COMPARE now and ifelse<n> is IF_THEN_ELSE.  */

  if (EQ != GET_CODE (XEXP (ifelse1, 0))
      || !REG_P (XEXP (comp1, 0))
      || !CONST_INT_P (XEXP (comp1, 1))
      || XEXP (ifelse1, 2) != pc_rtx
      || XEXP (ifelse2, 2) != pc_rtx
      || LABEL_REF != GET_CODE (XEXP (ifelse1, 1))
      || LABEL_REF != GET_CODE (XEXP (ifelse2, 1))
      || !COMPARISON_P (XEXP (ifelse2, 0))
      || cc0_rtx != XEXP (XEXP (ifelse1, 0), 0)
      || cc0_rtx != XEXP (XEXP (ifelse2, 0), 0)
      || const0_rtx != XEXP (XEXP (ifelse1, 0), 1)
      || const0_rtx != XEXP (XEXP (ifelse2, 0), 1))
    {
      return false;
    }

  /* We filtered the insn sequence to look like

        (set (cc0)
             (compare (reg:M N)
                      (const_int VAL)))
        (set (pc)
             (if_then_else (eq (cc0)
                               (const_int 0))
                           (label_ref L1)
                           (pc)))
                           
        (set (cc0)
             (compare (reg:M N)
                      (const_int VAL)))
        (set (pc)
             (if_then_else (CODE (cc0)
                                 (const_int 0))
                           (label_ref L2)
                           (pc)))
  */

  code = GET_CODE (XEXP (ifelse2, 0));

  /* Map GT/GTU to GE/GEU which is easier for AVR.
     The first two instructions compare/branch on EQ
     so we may replace the difficult
        
        if (x == VAL)   goto L1;
        if (x > VAL)    goto L2;

     with easy
         
         if (x == VAL)   goto L1;
         if (x >= VAL)   goto L2;

     Similarly, replace LE/LEU by LT/LTU.  */
  
  switch (code)
    {
    case EQ:
    case LT:  case LTU:
    case GE:  case GEU:
      break;

    case LE:  case LEU:
    case GT:  case GTU:
      code = avr_normalize_condition (code);
      break;
      
    default:
      return false;
    }

  /* Wrap the branches into UNSPECs so they won't be changed or
     optimized in the remainder.  */

  target = XEXP (XEXP (ifelse1, 1), 0);
  cond = XEXP (ifelse1, 0);
  jump = emit_jump_insn_after (gen_branch_unspec (target, cond), insn1);

  JUMP_LABEL (jump) = JUMP_LABEL (branch1);

  target = XEXP (XEXP (ifelse2, 1), 0);
  cond = gen_rtx_fmt_ee (code, VOIDmode, cc0_rtx, const0_rtx);
  jump = emit_jump_insn_after (gen_branch_unspec (target, cond), insn2);

  JUMP_LABEL (jump) = JUMP_LABEL (branch2);

  /* The comparisons in insn1 and insn2 are exactly the same;
     insn2 is superfluous so delete it.  */
     
  delete_insn (insn2);
  delete_insn (branch1);
  delete_insn (branch2);

  return true;
}


/* Implement `TARGET_MACHINE_DEPENDENT_REORG'.  */
/* Optimize conditional jumps.  */

static void
avr_reorg (void)
{
  rtx insn = get_insns();
  
  for (insn = next_real_insn (insn); insn; insn = next_real_insn (insn))
    {
      rtx pattern = avr_compare_pattern (insn);
      
      if (!pattern)
        continue;

      if (optimize
          && avr_reorg_remove_redundant_compare (insn))
        {
          continue;
        }

      if (compare_diff_p (insn))
        {
          /* Now we work under compare insn with difficult branch.  */
          
          rtx next = next_real_insn (insn);
          rtx pat = PATTERN (next);

          pattern = SET_SRC (pattern);
          
          if (true_regnum (XEXP (pattern, 0)) >= 0
              && true_regnum (XEXP (pattern, 1)) >= 0)
            {
              rtx x = XEXP (pattern, 0);
              rtx src = SET_SRC (pat);
              rtx t = XEXP (src,0);
              PUT_CODE (t, swap_condition (GET_CODE (t)));
              XEXP (pattern, 0) = XEXP (pattern, 1);
              XEXP (pattern, 1) = x;
              INSN_CODE (next) = -1;
            }
          else if (true_regnum (XEXP (pattern, 0)) >= 0
                   && XEXP (pattern, 1) == const0_rtx)
            {
              /* This is a tst insn, we can reverse it.  */
              rtx src = SET_SRC (pat);
              rtx t = XEXP (src,0);
    
              PUT_CODE (t, swap_condition (GET_CODE (t)));
              XEXP (pattern, 1) = XEXP (pattern, 0);
              XEXP (pattern, 0) = const0_rtx;
              INSN_CODE (next) = -1;
              INSN_CODE (insn) = -1;
            }
          else if (true_regnum (XEXP (pattern, 0)) >= 0
                   && CONST_INT_P (XEXP (pattern, 1)))
            {
              rtx x = XEXP (pattern, 1);
              rtx src = SET_SRC (pat);
              rtx t = XEXP (src,0);
              enum machine_mode mode = GET_MODE (XEXP (pattern, 0));
              
              if (avr_simplify_comparison_p (mode, GET_CODE (t), x))
                {
                  XEXP (pattern, 1) = gen_int_mode (INTVAL (x) + 1, mode);
                  PUT_CODE (t, avr_normalize_condition (GET_CODE (t)));
                  INSN_CODE (next) = -1;
                  INSN_CODE (insn) = -1;
                }
            }
        }
    }
}

/* Returns register number for function return value.*/

static inline unsigned int
avr_ret_register (void)
{
  return 24;
}

/* Worker function for TARGET_FUNCTION_VALUE_REGNO_P.  */

static bool
avr_function_value_regno_p (const unsigned int regno)
{
  return (regno == avr_ret_register ());
}

/* Create an RTX representing the place where a
   library function returns a value of mode MODE.  */

static rtx
avr_libcall_value (enum machine_mode mode,
                   const_rtx func ATTRIBUTE_UNUSED)
{
  int offs = GET_MODE_SIZE (mode);
  
  if (offs <= 4)
    offs = (offs + 1) & ~1;
  
  return gen_rtx_REG (mode, avr_ret_register () + 2 - offs);
}

/* Create an RTX representing the place where a
   function returns a value of data type VALTYPE.  */

static rtx
avr_function_value (const_tree type,
                    const_tree fn_decl_or_type ATTRIBUTE_UNUSED,
                    bool outgoing ATTRIBUTE_UNUSED)
{
  unsigned int offs;

  if (TYPE_MODE (type) != BLKmode)
    return avr_libcall_value (TYPE_MODE (type), NULL_RTX);
  
  offs = int_size_in_bytes (type);
  if (offs < 2)
    offs = 2;
  if (offs > 2 && offs < GET_MODE_SIZE (SImode))
    offs = GET_MODE_SIZE (SImode);
  else if (offs > GET_MODE_SIZE (SImode) && offs < GET_MODE_SIZE (DImode))
    offs = GET_MODE_SIZE (DImode);
  
  return gen_rtx_REG (BLKmode, avr_ret_register () + 2 - offs);
}

int
test_hard_reg_class (enum reg_class rclass, rtx x)
{
  int regno = true_regnum (x);
  if (regno < 0)
    return 0;

  if (TEST_HARD_REG_CLASS (rclass, regno))
    return 1;

  return 0;
}


/* Helper for jump_over_one_insn_p:  Test if INSN is a 2-word instruction
   and thus is suitable to be skipped by CPSE, SBRC, etc.  */

static bool
avr_2word_insn_p (rtx insn)
{
  if (avr_current_device->errata_skip
      || !insn
      || 2 != get_attr_length (insn))
    {
      return false;
    }

  switch (INSN_CODE (insn))
    {
    default:
      return false;
      
    case CODE_FOR_movqi_insn:
      {
        rtx set  = single_set (insn);
        rtx src  = SET_SRC (set);
        rtx dest = SET_DEST (set);
        
        /* Factor out LDS and STS from movqi_insn.  */
        
        if (MEM_P (dest)
            && (REG_P (src) || src == const0_rtx))
          {
            return CONSTANT_ADDRESS_P (XEXP (dest, 0));
          }
        else if (REG_P (dest)
                 && MEM_P (src))
          {
            return CONSTANT_ADDRESS_P (XEXP (src, 0));
          }
        
        return false;
      }

    case CODE_FOR_call_insn:
    case CODE_FOR_call_value_insn:
      return true;
    }
}


int
jump_over_one_insn_p (rtx insn, rtx dest)
{
  int uid = INSN_UID (GET_CODE (dest) == LABEL_REF
                      ? XEXP (dest, 0)
                      : dest);
  int jump_addr = INSN_ADDRESSES (INSN_UID (insn));
  int dest_addr = INSN_ADDRESSES (uid);
  int jump_offset = dest_addr - jump_addr - get_attr_length (insn);
  
  return (jump_offset == 1
          || (jump_offset == 2
              && avr_2word_insn_p (next_active_insn (insn))));
}

/* Returns 1 if a value of mode MODE can be stored starting with hard
   register number REGNO.  On the enhanced core, anything larger than
   1 byte must start in even numbered register for "movw" to work
   (this way we don't have to check for odd registers everywhere).  */

int
avr_hard_regno_mode_ok (int regno, enum machine_mode mode)
{
  /* NOTE: 8-bit values must not be disallowed for R28 or R29.
        Disallowing QI et al. in these regs might lead to code like
            (set (subreg:QI (reg:HI 28) n) ...)
        which will result in wrong code because reload does not
        handle SUBREGs of hard regsisters like this.
        This could be fixed in reload.  However, it appears
        that fixing reload is not wanted by reload people.  */
  
  /* Any GENERAL_REGS register can hold 8-bit values.  */
  
  if (GET_MODE_SIZE (mode) == 1)
    return 1;

  /* FIXME: Ideally, the following test is not needed.
        However, it turned out that it can reduce the number
        of spill fails.  AVR and it's poor endowment with
        address registers is extreme stress test for reload.  */
  
  if (GET_MODE_SIZE (mode) >= 4
      && regno >= REG_X)
    return 0;

  /* All modes larger than 8 bits should start in an even register.  */
  
  return !(regno & 1);
}


/* Implement `MODE_CODE_BASE_REG_CLASS'.  */

reg_class_t
avr_mode_code_base_reg_class (enum machine_mode mode ATTRIBUTE_UNUSED,
                              addr_space_t as, RTX_CODE outer_code,
                              RTX_CODE index_code ATTRIBUTE_UNUSED)
{
  if (!ADDR_SPACE_GENERIC_P (as))
    {
      return POINTER_Z_REGS;
    }
 
  if (!avr_strict_X)
    return reload_completed ? BASE_POINTER_REGS : POINTER_REGS;

  return PLUS == outer_code ? BASE_POINTER_REGS : POINTER_REGS;
}


/* Implement `REGNO_MODE_CODE_OK_FOR_BASE_P'.  */

bool
avr_regno_mode_code_ok_for_base_p (int regno,
                                   enum machine_mode mode ATTRIBUTE_UNUSED,
                                   addr_space_t as ATTRIBUTE_UNUSED,
                                   RTX_CODE outer_code,
                                   RTX_CODE index_code ATTRIBUTE_UNUSED)
{
  bool ok = false;
  
  if (!ADDR_SPACE_GENERIC_P (as))
    {
      if (regno < FIRST_PSEUDO_REGISTER
          && regno == REG_Z)
        {
          return true;
        }
      
      if (reg_renumber)
        {
          regno = reg_renumber[regno];
          
          if (regno == REG_Z)
            {
              return true;
            }
        }
      
      return false;
    }

  if (regno < FIRST_PSEUDO_REGISTER
      && (regno == REG_X
          || regno == REG_Y
          || regno == REG_Z
          || regno == ARG_POINTER_REGNUM))
    {
      ok = true;
    }
  else if (reg_renumber)
    {
      regno = reg_renumber[regno];

      if (regno == REG_X
          || regno == REG_Y
          || regno == REG_Z
          || regno == ARG_POINTER_REGNUM)
        {
          ok = true;
        }
    }

  if (avr_strict_X
      && PLUS == outer_code
      && regno == REG_X)
    {
      ok = false;
    }

  return ok;
}


/* A helper for `output_reload_insisf' and `output_reload_inhi'.  */
/* Set 32-bit register OP[0] to compile-time constant OP[1].
   CLOBBER_REG is a QI clobber register or NULL_RTX.
   LEN == NULL: output instructions.
   LEN != NULL: set *LEN to the length of the instruction sequence
                (in words) printed with LEN = NULL.
   If CLEAR_P is true, OP[0] had been cleard to Zero already.
   If CLEAR_P is false, nothing is known about OP[0].

   The effect on cc0 is as follows:

   Load 0 to any register except ZERO_REG : NONE
   Load ld register with any value        : NONE
   Anything else:                         : CLOBBER  */

static void
output_reload_in_const (rtx *op, rtx clobber_reg, int *len, bool clear_p)
{
  rtx src = op[1];
  rtx dest = op[0];
  rtx xval, xdest[4];
  int ival[4];
  int clobber_val = 1234;
  bool cooked_clobber_p = false;
  bool set_p = false;
  enum machine_mode mode = GET_MODE (dest);
  int n, n_bytes = GET_MODE_SIZE (mode);
  
  gcc_assert (REG_P (dest)
              && CONSTANT_P (src));

  if (len)
    *len = 0;
  
  /* (REG:SI 14) is special: It's neither in LD_REGS nor in NO_LD_REGS
     but has some subregs that are in LD_REGS.  Use the MSB (REG:QI 17).  */
  
  if (REGNO (dest) < 16
      && REGNO (dest) + GET_MODE_SIZE (mode) > 16)
    {
      clobber_reg = all_regs_rtx[REGNO (dest) + n_bytes - 1];
    }

  /* We might need a clobber reg but don't have one.  Look at the value to
     be loaded more closely.  A clobber is only needed if it is a symbol
     or contains a byte that is neither 0, -1 or a power of 2.  */
  
  if (NULL_RTX == clobber_reg
      && !test_hard_reg_class (LD_REGS, dest)
      && (! (CONST_INT_P (src) || CONST_DOUBLE_P (src))
          || !avr_popcount_each_byte (src, n_bytes,
                                      (1 << 0) | (1 << 1) | (1 << 8))))
    {
      /* We have no clobber register but need one.  Cook one up.
         That's cheaper than loading from constant pool.  */
      
      cooked_clobber_p = true;
      clobber_reg = all_regs_rtx[REG_Z + 1];
      avr_asm_len ("mov __tmp_reg__,%0", &clobber_reg, len, 1);
    }

  /* Now start filling DEST from LSB to MSB.  */
  
  for (n = 0; n < n_bytes; n++)
    {
      int ldreg_p;
      bool done_byte = false;
      int j;
      rtx xop[3];

      /* Crop the n-th destination byte.  */

      xdest[n] = simplify_gen_subreg (QImode, dest, mode, n);
      ldreg_p = test_hard_reg_class (LD_REGS, xdest[n]);

      if (!CONST_INT_P (src)
          && !CONST_DOUBLE_P (src))
        {
          static const char* const asm_code[][2] =
            {
              { "ldi %2,lo8(%1)"  CR_TAB "mov %0,%2",    "ldi %0,lo8(%1)"  },
              { "ldi %2,hi8(%1)"  CR_TAB "mov %0,%2",    "ldi %0,hi8(%1)"  },
              { "ldi %2,hlo8(%1)" CR_TAB "mov %0,%2",    "ldi %0,hlo8(%1)" },
              { "ldi %2,hhi8(%1)" CR_TAB "mov %0,%2",    "ldi %0,hhi8(%1)" }
            };
          
          xop[0] = xdest[n];
          xop[1] = src;
          xop[2] = clobber_reg;

          avr_asm_len (asm_code[n][ldreg_p], xop, len, ldreg_p ? 1 : 2);
          
          continue;
        }

      /* Crop the n-th source byte.  */

      xval = simplify_gen_subreg (QImode, src, mode, n);
      ival[n] = INTVAL (xval);

      /* Look if we can reuse the low word by means of MOVW.  */
      
      if (n == 2
          && n_bytes >= 4
          && AVR_HAVE_MOVW)
        {
          rtx lo16 = simplify_gen_subreg (HImode, src, mode, 0);
          rtx hi16 = simplify_gen_subreg (HImode, src, mode, 2);

          if (INTVAL (lo16) == INTVAL (hi16))
            {
              if (0 != INTVAL (lo16)
                  || !clear_p)
                {
                  avr_asm_len ("movw %C0,%A0", &op[0], len, 1);
                }
              
              break;
            }
        }

      /* Don't use CLR so that cc0 is set as expected.  */
      
      if (ival[n] == 0)
        {
          if (!clear_p)
            avr_asm_len (ldreg_p ? "ldi %0,0"
                         : ZERO_REGNO == REGNO (xdest[n]) ? "clr %0"
                         : "mov %0,__zero_reg__",
                         &xdest[n], len, 1);
          continue;
        }

      if (clobber_val == ival[n]
          && REGNO (clobber_reg) == REGNO (xdest[n]))
        {
          continue;
        }

      /* LD_REGS can use LDI to move a constant value */
      
      if (ldreg_p)
        {
          xop[0] = xdest[n];
          xop[1] = xval;
          avr_asm_len ("ldi %0,lo8(%1)", xop, len, 1);
          continue;
        }

      /* Try to reuse value already loaded in some lower byte. */
      
      for (j = 0; j < n; j++)
        if (ival[j] == ival[n])
          {
            xop[0] = xdest[n];
            xop[1] = xdest[j];
            
            avr_asm_len ("mov %0,%1", xop, len, 1);
            done_byte = true;
            break;
          }

      if (done_byte)
        continue;

      /* Need no clobber reg for -1: Use CLR/DEC */
      
      if (-1 == ival[n])
        {
          if (!clear_p)
            avr_asm_len ("clr %0", &xdest[n], len, 1);
          
          avr_asm_len ("dec %0", &xdest[n], len, 1);
          continue;
        }
      else if (1 == ival[n])
        {
          if (!clear_p)
            avr_asm_len ("clr %0", &xdest[n], len, 1);
          
          avr_asm_len ("inc %0", &xdest[n], len, 1);
          continue;
        }

      /* Use T flag or INC to manage powers of 2 if we have
         no clobber reg.  */

      if (NULL_RTX == clobber_reg
          && single_one_operand (xval, QImode))
        {
          xop[0] = xdest[n];
          xop[1] = GEN_INT (exact_log2 (ival[n] & GET_MODE_MASK (QImode)));

          gcc_assert (constm1_rtx != xop[1]);

          if (!set_p)
            {
              set_p = true;
              avr_asm_len ("set", xop, len, 1);
            }

          if (!clear_p)
            avr_asm_len ("clr %0", xop, len, 1);
          
          avr_asm_len ("bld %0,%1", xop, len, 1);
          continue;
        }

      /* We actually need the LD_REGS clobber reg.  */

      gcc_assert (NULL_RTX != clobber_reg);
        
      xop[0] = xdest[n];
      xop[1] = xval;
      xop[2] = clobber_reg;
      clobber_val = ival[n];
        
      avr_asm_len ("ldi %2,lo8(%1)" CR_TAB
                   "mov %0,%2", xop, len, 2);
    }
  
  /* If we cooked up a clobber reg above, restore it.  */
  
  if (cooked_clobber_p)
    {
      avr_asm_len ("mov %0,__tmp_reg__", &clobber_reg, len, 1);
    }
}


/* Reload the constant OP[1] into the HI register OP[0].
   CLOBBER_REG is a QI clobber reg needed to move vast majority of consts
   into a NO_LD_REGS register.  If CLOBBER_REG is NULL_RTX we either don't
   need a clobber reg or have to cook one up.

   PLEN == NULL: Output instructions.
   PLEN != NULL: Output nothing.  Set *PLEN to number of words occupied
                 by the insns printed.

   Return "".  */

const char*
output_reload_inhi (rtx *op, rtx clobber_reg, int *plen)
{
  output_reload_in_const (op, clobber_reg, plen, false);
  return "";
}


/* Reload a SI or SF compile time constant OP[1] into the register OP[0].
   CLOBBER_REG is a QI clobber reg needed to move vast majority of consts
   into a NO_LD_REGS register.  If CLOBBER_REG is NULL_RTX we either don't
   need a clobber reg or have to cook one up.

   LEN == NULL: Output instructions.
   
   LEN != NULL: Output nothing.  Set *LEN to number of words occupied
                by the insns printed.

   Return "".  */

const char *
output_reload_insisf (rtx *op, rtx clobber_reg, int *len)
{
  if (AVR_HAVE_MOVW
      && !test_hard_reg_class (LD_REGS, op[0])
      && (CONST_INT_P (op[1])
          || CONST_DOUBLE_P (op[1])))
    {
      int len_clr, len_noclr;
      
      /* In some cases it is better to clear the destination beforehand, e.g.

             CLR R2   CLR R3   MOVW R4,R2   INC R2

         is shorther than

             CLR R2   INC R2   CLR  R3      CLR R4   CLR R5

         We find it too tedious to work that out in the print function.
         Instead, we call the print function twice to get the lengths of
         both methods and use the shortest one.  */
         
      output_reload_in_const (op, clobber_reg, &len_clr, true);
      output_reload_in_const (op, clobber_reg, &len_noclr, false);
      
      if (len_noclr - len_clr == 4)
        {
          /* Default needs 4 CLR instructions: clear register beforehand.  */
          
          avr_asm_len ("mov %A0,__zero_reg__" CR_TAB
                       "mov %B0,__zero_reg__" CR_TAB
                       "movw %C0,%A0", &op[0], len, 3);
          
          output_reload_in_const (op, clobber_reg, len, true);
          
          if (len)
            *len += 3;

          return "";
        }
    }

  /* Default: destination not pre-cleared.  */

  output_reload_in_const (op, clobber_reg, len, false);
  return "";
}

const char *
avr_out_reload_inpsi (rtx *op, rtx clobber_reg, int *len)
{
  output_reload_in_const (op, clobber_reg, len, false);
  return "";
}

void
avr_output_bld (rtx operands[], int bit_nr)
{
  static char s[] = "bld %A0,0";

  s[5] = 'A' + (bit_nr >> 3);
  s[8] = '0' + (bit_nr & 7);
  output_asm_insn (s, operands);
}

void
avr_output_addr_vec_elt (FILE *stream, int value)
{
  if (AVR_HAVE_JMP_CALL)
    fprintf (stream, "\t.word gs(.L%d)\n", value);
  else
    fprintf (stream, "\trjmp .L%d\n", value);
}

/* Returns true if SCRATCH are safe to be allocated as a scratch
   registers (for a define_peephole2) in the current function.  */

static bool
avr_hard_regno_scratch_ok (unsigned int regno)
{
  /* Interrupt functions can only use registers that have already been saved
     by the prologue, even if they would normally be call-clobbered.  */

  if ((cfun->machine->is_interrupt || cfun->machine->is_signal)
      && !df_regs_ever_live_p (regno))
    return false;

  /* Don't allow hard registers that might be part of the frame pointer.
     Some places in the compiler just test for [HARD_]FRAME_POINTER_REGNUM
     and don't care for a frame pointer that spans more than one register.  */

  if ((!reload_completed || frame_pointer_needed)
      && (regno == REG_Y || regno == REG_Y + 1))
    {
      return false;
    }

  return true;
}

/* Return nonzero if register OLD_REG can be renamed to register NEW_REG.  */

int
avr_hard_regno_rename_ok (unsigned int old_reg,
                          unsigned int new_reg)
{
  /* Interrupt functions can only use registers that have already been
     saved by the prologue, even if they would normally be
     call-clobbered.  */

  if ((cfun->machine->is_interrupt || cfun->machine->is_signal)
      && !df_regs_ever_live_p (new_reg))
    return 0;

  /* Don't allow hard registers that might be part of the frame pointer.
     Some places in the compiler just test for [HARD_]FRAME_POINTER_REGNUM
     and don't care for a frame pointer that spans more than one register.  */

  if ((!reload_completed || frame_pointer_needed)
      && (old_reg == REG_Y || old_reg == REG_Y + 1
          || new_reg == REG_Y || new_reg == REG_Y + 1))
    {
      return 0;
    }
  
  return 1;
}

/* Output a branch that tests a single bit of a register (QI, HI, SI or DImode)
   or memory location in the I/O space (QImode only).

   Operand 0: comparison operator (must be EQ or NE, compare bit to zero).
   Operand 1: register operand to test, or CONST_INT memory address.
   Operand 2: bit number.
   Operand 3: label to jump to if the test is true.  */

const char *
avr_out_sbxx_branch (rtx insn, rtx operands[])
{
  enum rtx_code comp = GET_CODE (operands[0]);
  bool long_jump = get_attr_length (insn) >= 4;
  bool reverse = long_jump || jump_over_one_insn_p (insn, operands[3]);

  if (comp == GE)
    comp = EQ;
  else if (comp == LT)
    comp = NE;

  if (reverse)
    comp = reverse_condition (comp);

  switch (GET_CODE (operands[1]))
    {
    default:
      gcc_unreachable();
      
    case CONST_INT:

      if (low_io_address_operand (operands[1], QImode))
        {
          if (comp == EQ)
            output_asm_insn ("sbis %i1,%2", operands);
          else
            output_asm_insn ("sbic %i1,%2", operands);
        }
      else
        {
          output_asm_insn ("in __tmp_reg__,%i1", operands);
          if (comp == EQ)
            output_asm_insn ("sbrs __tmp_reg__,%2", operands);
          else
            output_asm_insn ("sbrc __tmp_reg__,%2", operands);
        }

      break; /* CONST_INT */

    case REG:

      if (GET_MODE (operands[1]) == QImode)
        {
          if (comp == EQ)
            output_asm_insn ("sbrs %1,%2", operands);
          else
            output_asm_insn ("sbrc %1,%2", operands);
        }
      else  /* HImode, PSImode or SImode */
        {
          static char buf[] = "sbrc %A1,0";
          unsigned int bit_nr = UINTVAL (operands[2]);

          buf[3] = (comp == EQ) ? 's' : 'c';
          buf[6] = 'A' + (bit_nr / 8);
          buf[9] = '0' + (bit_nr % 8);
          output_asm_insn (buf, operands);
        }

      break; /* REG */
    }        /* switch */

  if (long_jump)
    return ("rjmp .+4" CR_TAB
            "jmp %x3");

  if (!reverse)
    return "rjmp %x3";

  return "";
}

/* Worker function for TARGET_ASM_CONSTRUCTOR.  */

static void
avr_asm_out_ctor (rtx symbol, int priority)
{
  fputs ("\t.global __do_global_ctors\n", asm_out_file);
  default_ctor_section_asm_out_constructor (symbol, priority);
}

/* Worker function for TARGET_ASM_DESTRUCTOR.  */

static void
avr_asm_out_dtor (rtx symbol, int priority)
{
  fputs ("\t.global __do_global_dtors\n", asm_out_file);
  default_dtor_section_asm_out_destructor (symbol, priority);
}

/* Worker function for TARGET_RETURN_IN_MEMORY.  */

static bool
avr_return_in_memory (const_tree type, const_tree fntype ATTRIBUTE_UNUSED)
{
  if (TYPE_MODE (type) == BLKmode)
    {
      HOST_WIDE_INT size = int_size_in_bytes (type);
      return (size == -1 || size > 8);
    }
  else
    return false;
}

/* Worker function for CASE_VALUES_THRESHOLD.  */

static unsigned int
avr_case_values_threshold (void)
{
  return (!AVR_HAVE_JMP_CALL || TARGET_CALL_PROLOGUES) ? 8 : 17;
}


/* Implement `TARGET_ADDR_SPACE_ADDRESS_MODE'.  */

static enum machine_mode
avr_addr_space_address_mode (addr_space_t as)
{
  return avr_addrspace[as].pointer_size == 3 ? PSImode : HImode;
}


/* Implement `TARGET_ADDR_SPACE_POINTER_MODE'.  */

static enum machine_mode
avr_addr_space_pointer_mode (addr_space_t as)
{
  return avr_addr_space_address_mode (as);
}


/* Helper for following function.  */

static bool
avr_reg_ok_for_pgm_addr (rtx reg, bool strict)
{
  gcc_assert (REG_P (reg));

  if (strict)
    {
      return REGNO (reg) == REG_Z;
    }
  
  /* Avoid combine to propagate hard regs.  */
  
  if (can_create_pseudo_p()
      && REGNO (reg) < REG_Z)
    {
      return false;
    }
  
  return true;
}


/* Implement `TARGET_ADDR_SPACE_LEGITIMATE_ADDRESS_P'.  */

static bool
avr_addr_space_legitimate_address_p (enum machine_mode mode, rtx x,
                                     bool strict, addr_space_t as)
{
  bool ok = false;

  switch (as)
    {
    default:
      gcc_unreachable();
      
    case ADDR_SPACE_GENERIC:
      return avr_legitimate_address_p (mode, x, strict);

    case ADDR_SPACE_FLASH:
    case ADDR_SPACE_FLASH1:
    case ADDR_SPACE_FLASH2:
    case ADDR_SPACE_FLASH3:
    case ADDR_SPACE_FLASH4:
    case ADDR_SPACE_FLASH5:

      switch (GET_CODE (x))
        {
        case REG:
          ok = avr_reg_ok_for_pgm_addr (x, strict);
          break;
          
        case POST_INC:
          ok = avr_reg_ok_for_pgm_addr (XEXP (x, 0), strict);
          break;
          
        default:
          break;
        }

      break; /* FLASH */
      
    case ADDR_SPACE_MEMX:
      if (REG_P (x))
        ok = (!strict
              && can_create_pseudo_p());

      if (LO_SUM == GET_CODE (x))
        {
          rtx hi = XEXP (x, 0);
          rtx lo = XEXP (x, 1);

          ok = (REG_P (hi)
                && (!strict || REGNO (hi) < FIRST_PSEUDO_REGISTER)
                && REG_P (lo)
                && REGNO (lo) == REG_Z);
        }
      
      break; /* MEMX */
    }

  if (avr_log.legitimate_address_p)
    {
      avr_edump ("\n%?: ret=%b, mode=%m strict=%d "
                 "reload_completed=%d reload_in_progress=%d %s:",
                 ok, mode, strict, reload_completed, reload_in_progress,
                 reg_renumber ? "(reg_renumber)" : "");
      
      if (GET_CODE (x) == PLUS
          && REG_P (XEXP (x, 0))
          && CONST_INT_P (XEXP (x, 1))
          && IN_RANGE (INTVAL (XEXP (x, 1)), 0, MAX_LD_OFFSET (mode))
          && reg_renumber)
        {
          avr_edump ("(r%d ---> r%d)", REGNO (XEXP (x, 0)),
                     true_regnum (XEXP (x, 0)));
        }
      
      avr_edump ("\n%r\n", x);
    }

  return ok;
}


/* Implement `TARGET_ADDR_SPACE_LEGITIMIZE_ADDRESS'.  */

static rtx
avr_addr_space_legitimize_address (rtx x, rtx old_x,
                                   enum machine_mode mode, addr_space_t as)
{
  if (ADDR_SPACE_GENERIC_P (as))
    return avr_legitimize_address (x, old_x, mode);

  if (avr_log.legitimize_address)
    {
      avr_edump ("\n%?: mode=%m\n %r\n", mode, old_x);
    }

  return old_x;
}


/* Implement `TARGET_ADDR_SPACE_CONVERT'.  */

static rtx
avr_addr_space_convert (rtx src, tree type_from, tree type_to)
{
  addr_space_t as_from = TYPE_ADDR_SPACE (TREE_TYPE (type_from));
  addr_space_t as_to = TYPE_ADDR_SPACE (TREE_TYPE (type_to));

  if (avr_log.progmem)
    avr_edump ("\n%!: op = %r\nfrom = %t\nto = %t\n",
               src, type_from, type_to);

  /* Up-casting from 16-bit to 24-bit pointer.  */
  
  if (as_from != ADDR_SPACE_MEMX
      && as_to == ADDR_SPACE_MEMX)
    {
      int msb;
      rtx sym = src;
      rtx reg = gen_reg_rtx (PSImode);

      while (CONST == GET_CODE (sym) || PLUS == GET_CODE (sym))
        sym = XEXP (sym, 0);

      /* Look at symbol flags:  avr_encode_section_info set the flags
         also if attribute progmem was seen so that we get the right
         promotion for, e.g. PSTR-like strings that reside in generic space
         but are located in flash.  In that case we patch the incoming
         address space.  */

      if (SYMBOL_REF == GET_CODE (sym)
          && ADDR_SPACE_FLASH == AVR_SYMBOL_GET_ADDR_SPACE (sym))
        {
          as_from = ADDR_SPACE_FLASH;
        }

      /* Linearize memory: RAM has bit 23 set.  */
             
      msb = ADDR_SPACE_GENERIC_P (as_from)
        ? 0x80
        : avr_addrspace[as_from].segment % avr_current_arch->n_segments;

      src = force_reg (Pmode, src);
      
      emit_insn (msb == 0
                 ? gen_zero_extendhipsi2 (reg, src)
                 : gen_n_extendhipsi2 (reg, gen_int_mode (msb, QImode), src));
          
      return reg;
    }

  /* Down-casting from 24-bit to 16-bit throws away the high byte.  */

  if (as_from == ADDR_SPACE_MEMX
      && as_to != ADDR_SPACE_MEMX)
    {
      rtx new_src = gen_reg_rtx (Pmode);

      src = force_reg (PSImode, src);
      
      emit_move_insn (new_src,
                      simplify_gen_subreg (Pmode, src, PSImode, 0));
      return new_src;
    }
  
  return src;
}


/* Implement `TARGET_ADDR_SPACE_SUBSET_P'.  */

static bool
avr_addr_space_subset_p (addr_space_t subset ATTRIBUTE_UNUSED,
                         addr_space_t superset ATTRIBUTE_UNUSED)
{
  /* Allow any kind of pointer mess.  */
  
  return true;
}


/* Worker function for movmemhi expander.
   XOP[0]  Destination as MEM:BLK
   XOP[1]  Source      "     "
   XOP[2]  # Bytes to copy

   Return TRUE  if the expansion is accomplished.
   Return FALSE if the operand compination is not supported.  */

bool
avr_emit_movmemhi (rtx *xop)
{
  HOST_WIDE_INT count;
  enum machine_mode loop_mode;
  addr_space_t as = MEM_ADDR_SPACE (xop[1]);
  rtx loop_reg, addr0, addr1, a_src, a_dest, insn, xas, reg_x;
  rtx a_hi8 = NULL_RTX;

  if (avr_mem_flash_p (xop[0]))
    return false;

  if (!CONST_INT_P (xop[2]))
    return false;

  count = INTVAL (xop[2]);
  if (count <= 0)
    return false;

  a_src  = XEXP (xop[1], 0);
  a_dest = XEXP (xop[0], 0);

  if (PSImode == GET_MODE (a_src))
    {
      gcc_assert (as == ADDR_SPACE_MEMX);

      loop_mode = (count < 0x100) ? QImode : HImode;
      loop_reg = gen_rtx_REG (loop_mode, 24);
      emit_move_insn (loop_reg, gen_int_mode (count, loop_mode));

      addr1 = simplify_gen_subreg (HImode, a_src, PSImode, 0);
      a_hi8 = simplify_gen_subreg (QImode, a_src, PSImode, 2);
    }
  else
    {
      int segment = avr_addrspace[as].segment % avr_current_arch->n_segments;
      
      if (segment
          && avr_current_arch->n_segments > 1)
        {
          a_hi8 = GEN_INT (segment);
          emit_move_insn (rampz_rtx, a_hi8 = copy_to_mode_reg (QImode, a_hi8));
        }
      else if (!ADDR_SPACE_GENERIC_P (as))
        {
          as = ADDR_SPACE_FLASH;
        }
      
      addr1 = a_src;

      loop_mode = (count <= 0x100) ? QImode : HImode;
      loop_reg = copy_to_mode_reg (loop_mode, gen_int_mode (count, loop_mode));
    }

  xas = GEN_INT (as);

  /* FIXME: Register allocator might come up with spill fails if it is left
        on its own.  Thus, we allocate the pointer registers by hand:
        Z = source address
        X = destination address  */

  emit_move_insn (lpm_addr_reg_rtx, addr1);
  addr1 = lpm_addr_reg_rtx;

  reg_x = gen_rtx_REG (HImode, REG_X);
  emit_move_insn (reg_x, a_dest);
  addr0 = reg_x;

  /* FIXME: Register allocator does a bad job and might spill address
        register(s) inside the loop leading to additional move instruction
        to/from stack which could clobber tmp_reg.  Thus, do *not* emit
        load and store as seperate insns.  Instead, we perform the copy
        by means of one monolithic insn.  */

  gcc_assert (TMP_REGNO == LPM_REGNO);

  if (as != ADDR_SPACE_MEMX)
    {
      /* Load instruction ([E]LPM or LD) is known at compile time:
         Do the copy-loop inline.  */
      
      rtx (*fun) (rtx, rtx, rtx, rtx, rtx, rtx, rtx, rtx)
        = QImode == loop_mode ? gen_movmem_qi : gen_movmem_hi;

      insn = fun (addr0, addr1, xas, loop_reg,
                  addr0, addr1, tmp_reg_rtx, loop_reg);
    }
  else
    {
      rtx loop_reg16 = gen_rtx_REG (HImode, 24);
      rtx r23 = gen_rtx_REG (QImode, 23);
      rtx (*fun) (rtx, rtx, rtx, rtx, rtx, rtx, rtx, rtx, rtx, rtx, rtx)
        = QImode == loop_mode ? gen_movmemx_qi : gen_movmemx_hi;

      emit_move_insn (r23, a_hi8);
      
      insn = fun (addr0, addr1, xas, loop_reg, addr0, addr1,
                  lpm_reg_rtx, loop_reg16, r23, r23, GEN_INT (avr_addr.rampz));
    }

  set_mem_addr_space (SET_SRC (XVECEXP (insn, 0, 0)), as);
  emit_insn (insn);

  return true;
}


/* Print assembler for movmem_qi, movmem_hi insns...
       $0, $4 : & dest
       $1, $5 : & src
       $2     : Address Space
       $3, $7 : Loop register
       $6     : Scratch register

   ...and movmem_qi_elpm, movmem_hi_elpm insns.
   
       $8, $9 : hh8 (& src)
       $10    : RAMPZ_ADDR
*/

const char*
avr_out_movmem (rtx insn ATTRIBUTE_UNUSED, rtx *xop, int *plen)
{
  addr_space_t as = (addr_space_t) INTVAL (xop[2]);
  enum machine_mode loop_mode = GET_MODE (xop[3]);

  bool sbiw_p = test_hard_reg_class (ADDW_REGS, xop[3]);

  gcc_assert (REG_X == REGNO (xop[0])
              && REG_Z == REGNO (xop[1]));

  if (plen)
    *plen = 0;

  /* Loop label */

  avr_asm_len ("0:", xop, plen, 0);

  /* Load with post-increment */

  switch (as)
    {
    default:
      gcc_unreachable();
      
    case ADDR_SPACE_GENERIC:

      avr_asm_len ("ld %6,%a1+", xop, plen, 1);
      break;
      
    case ADDR_SPACE_FLASH:

      if (AVR_HAVE_LPMX)
        avr_asm_len ("lpm %6,%a1+", xop, plen, 1);
      else
        avr_asm_len ("lpm" CR_TAB
                     "adiw %1,1", xop, plen, 2);
      break;
      
    case ADDR_SPACE_FLASH1:
    case ADDR_SPACE_FLASH2:
    case ADDR_SPACE_FLASH3:
    case ADDR_SPACE_FLASH4:
    case ADDR_SPACE_FLASH5:

      if (AVR_HAVE_ELPMX)
        avr_asm_len ("elpm %6,%a1+", xop, plen, 1);
      else
        avr_asm_len ("elpm" CR_TAB
                     "adiw %1,1", xop, plen, 2);
      break;
    }

  /* Store with post-increment */

  avr_asm_len ("st %a0+,%6", xop, plen, 1);

  /* Decrement loop-counter and set Z-flag */

  if (QImode == loop_mode)
    {
      avr_asm_len ("dec %3", xop, plen, 1);
    }
  else if (sbiw_p)
    {
      avr_asm_len ("sbiw %3,1", xop, plen, 1);
    }
  else
    {
      avr_asm_len ("subi %A3,1" CR_TAB
                   "sbci %B3,0", xop, plen, 2);
    }

  /* Loop until zero */
  
  return avr_asm_len ("brne 0b", xop, plen, 1);
}


\f
/* Helper for __builtin_avr_delay_cycles */

static void
avr_expand_delay_cycles (rtx operands0)
{
  unsigned HOST_WIDE_INT cycles = UINTVAL (operands0);
  unsigned HOST_WIDE_INT cycles_used;
  unsigned HOST_WIDE_INT loop_count;
  
  if (IN_RANGE (cycles, 83886082, 0xFFFFFFFF))
    {
      loop_count = ((cycles - 9) / 6) + 1;
      cycles_used = ((loop_count - 1) * 6) + 9;
      emit_insn (gen_delay_cycles_4 (gen_int_mode (loop_count, SImode)));
      cycles -= cycles_used;
    }
  
  if (IN_RANGE (cycles, 262145, 83886081))
    {
      loop_count = ((cycles - 7) / 5) + 1;
      if (loop_count > 0xFFFFFF)
        loop_count = 0xFFFFFF;
      cycles_used = ((loop_count - 1) * 5) + 7;
      emit_insn (gen_delay_cycles_3 (gen_int_mode (loop_count, SImode)));
      cycles -= cycles_used;
    }
  
  if (IN_RANGE (cycles, 768, 262144))
    {
      loop_count = ((cycles - 5) / 4) + 1;
      if (loop_count > 0xFFFF)
        loop_count = 0xFFFF;
      cycles_used = ((loop_count - 1) * 4) + 5;
      emit_insn (gen_delay_cycles_2 (gen_int_mode (loop_count, HImode)));
      cycles -= cycles_used;
    }
  
  if (IN_RANGE (cycles, 6, 767))
    {
      loop_count = cycles / 3;
      if (loop_count > 255) 
        loop_count = 255;
      cycles_used = loop_count * 3;
      emit_insn (gen_delay_cycles_1 (gen_int_mode (loop_count, QImode)));
      cycles -= cycles_used;
      }
  
  while (cycles >= 2)
    {
      emit_insn (gen_nopv (GEN_INT(2)));
      cycles -= 2;
    }

  if (cycles == 1)
    {
      emit_insn (gen_nopv (GEN_INT(1)));
      cycles--;
    }
}


/* Return VAL * BASE + DIGIT.  BASE = 0 is shortcut for BASE = 2^{32}   */

static double_int
avr_double_int_push_digit (double_int val, int base,
                           unsigned HOST_WIDE_INT digit)
{
  val = 0 == base
    ? double_int_lshift (val, 32, 64, false)
    : double_int_mul (val, uhwi_to_double_int (base));
  
  return double_int_add (val, uhwi_to_double_int (digit));
}


/* Compute the image of x under f, i.e. perform   x --> f(x)    */

static int
avr_map (double_int f, int x)
{
  return 0xf & double_int_to_uhwi (double_int_rshift (f, 4*x, 64, false));
}


/* Return some metrics of map A.  */

enum
  {
    /* Number of fixed points in { 0 ... 7 } */
    MAP_FIXED_0_7,

    /* Size of preimage of non-fixed points in { 0 ... 7 } */
    MAP_NONFIXED_0_7,
    
    /* Mask representing the fixed points in { 0 ... 7 } */
    MAP_MASK_FIXED_0_7,
    
    /* Size of the preimage of { 0 ... 7 } */
    MAP_PREIMAGE_0_7,
    
    /* Mask that represents the preimage of { f } */
    MAP_MASK_PREIMAGE_F
  };

static unsigned
avr_map_metric (double_int a, int mode)
{
  unsigned i, metric = 0;

  for (i = 0; i < 8; i++)
    {
      unsigned ai = avr_map (a, i);

      if (mode == MAP_FIXED_0_7)
        metric += ai == i;
      else if (mode == MAP_NONFIXED_0_7)
        metric += ai < 8 && ai != i;
      else if (mode == MAP_MASK_FIXED_0_7)
        metric |= ((unsigned) (ai == i)) << i;
      else if (mode == MAP_PREIMAGE_0_7)
        metric += ai < 8;
      else if (mode == MAP_MASK_PREIMAGE_F)
        metric |= ((unsigned) (ai == 0xf)) << i;
      else
        gcc_unreachable();
    }
  
  return metric;
}


/* Return true if IVAL has a 0xf in its hexadecimal representation
   and false, otherwise.  Only nibbles 0..7 are taken into account.
   Used as constraint helper for C0f and Cxf.  */

bool
avr_has_nibble_0xf (rtx ival)
{
  return 0 != avr_map_metric (rtx_to_double_int (ival), MAP_MASK_PREIMAGE_F);
}


/* We have a set of bits that are mapped by a function F.
   Try to decompose F by means of a second function G so that

      F = F o G^-1 o G

   and

      cost (F o G^-1) + cost (G)  <  cost (F)

   Example:  Suppose builtin insert_bits supplies us with the map
   F = 0x3210ffff.  Instead of doing 4 bit insertions to get the high
   nibble of the result, we can just as well rotate the bits before inserting
   them and use the map 0x7654ffff which is cheaper than the original map.
   For this example G = G^-1 = 0x32107654 and F o G^-1 = 0x7654ffff.  */
   
typedef struct
{
  /* tree code of binary function G */
  enum tree_code code;

  /* The constant second argument of G */
  int arg;

  /* G^-1, the inverse of G (*, arg) */
  unsigned ginv;

  /* The cost of appplying G (*, arg) */
  int cost;

  /* The composition F o G^-1 (*, arg) for some function F */
  double_int map;

  /* For debug purpose only */
  const char *str;
} avr_map_op_t;

static const avr_map_op_t avr_map_op[] =
  {
    { LROTATE_EXPR, 0, 0x76543210, 0, { 0, 0 }, "id" },
    { LROTATE_EXPR, 1, 0x07654321, 2, { 0, 0 }, "<<<" },
    { LROTATE_EXPR, 2, 0x10765432, 4, { 0, 0 }, "<<<" },
    { LROTATE_EXPR, 3, 0x21076543, 4, { 0, 0 }, "<<<" },
    { LROTATE_EXPR, 4, 0x32107654, 1, { 0, 0 }, "<<<" },
    { LROTATE_EXPR, 5, 0x43210765, 3, { 0, 0 }, "<<<" },
    { LROTATE_EXPR, 6, 0x54321076, 5, { 0, 0 }, "<<<" },
    { LROTATE_EXPR, 7, 0x65432107, 3, { 0, 0 }, "<<<" },
    { RSHIFT_EXPR, 1, 0x6543210c, 1, { 0, 0 }, ">>" },
    { RSHIFT_EXPR, 1, 0x7543210c, 1, { 0, 0 }, ">>" },
    { RSHIFT_EXPR, 2, 0x543210cc, 2, { 0, 0 }, ">>" },
    { RSHIFT_EXPR, 2, 0x643210cc, 2, { 0, 0 }, ">>" },
    { RSHIFT_EXPR, 2, 0x743210cc, 2, { 0, 0 }, ">>" },
    { LSHIFT_EXPR, 1, 0xc7654321, 1, { 0, 0 }, "<<" },
    { LSHIFT_EXPR, 2, 0xcc765432, 2, { 0, 0 }, "<<" }
  };


/* Try to decompose F as F = (F o G^-1) o G as described above.
   The result is a struct representing F o G^-1 and G.
   If result.cost < 0 then such a decomposition does not exist.  */
   
static avr_map_op_t
avr_map_decompose (double_int f, const avr_map_op_t *g, bool val_const_p)
{
  int i;
  bool val_used_p = 0 != avr_map_metric (f, MAP_MASK_PREIMAGE_F);
  avr_map_op_t f_ginv = *g;
  double_int ginv = uhwi_to_double_int (g->ginv);

  f_ginv.cost = -1;
  
  /* Step 1:  Computing F o G^-1  */

  for (i = 7; i >= 0; i--)
    {
      int x = avr_map (f, i);
      
      if (x <= 7)
        {
          x = avr_map (ginv, x);

          /* The bit is no element of the image of G: no avail (cost = -1)  */
          
          if (x > 7)
            return f_ginv;
        }
      
      f_ginv.map = avr_double_int_push_digit (f_ginv.map, 16, x);
    }

  /* Step 2:  Compute the cost of the operations.
     The overall cost of doing an operation prior to the insertion is
      the cost of the insertion plus the cost of the operation.  */

  /* Step 2a:  Compute cost of F o G^-1  */

  if (0 == avr_map_metric (f_ginv.map, MAP_NONFIXED_0_7))
    {
      /* The mapping consists only of fixed points and can be folded
         to AND/OR logic in the remainder.  Reasonable cost is 3. */

      f_ginv.cost = 2 + (val_used_p && !val_const_p);
    }
  else
    {
      rtx xop[4];

      /* Get the cost of the insn by calling the output worker with some
         fake values.  Mimic effect of reloading xop[3]: Unused operands
         are mapped to 0 and used operands are reloaded to xop[0].  */

      xop[0] = all_regs_rtx[24];
      xop[1] = gen_int_mode (double_int_to_uhwi (f_ginv.map), SImode);
      xop[2] = all_regs_rtx[25];
      xop[3] = val_used_p ? xop[0] : const0_rtx;
  
      avr_out_insert_bits (xop, &f_ginv.cost);
      
      f_ginv.cost += val_const_p && val_used_p ? 1 : 0;
    }
  
  /* Step 2b:  Add cost of G  */

  f_ginv.cost += g->cost;

  if (avr_log.builtin)
    avr_edump (" %s%d=%d", g->str, g->arg, f_ginv.cost);

  return f_ginv;
}


/* Insert bits from XOP[1] into XOP[0] according to MAP.
   XOP[0] and XOP[1] don't overlap.
   If FIXP_P = true:  Move all bits according to MAP using BLD/BST sequences.
   If FIXP_P = false: Just move the bit if its position in the destination
   is different to its source position.  */

static void
avr_move_bits (rtx *xop, double_int map, bool fixp_p, int *plen)
{
  int bit_dest, b;

  /* T-flag contains this bit of the source, i.e. of XOP[1]  */
  int t_bit_src = -1;

  /* We order the operations according to the requested source bit b.  */
  
  for (b = 0; b < 8; b++)
    for (bit_dest = 0; bit_dest < 8; bit_dest++)
      {
        int bit_src = avr_map (map, bit_dest);
        
        if (b != bit_src
            || bit_src >= 8
            /* Same position: No need to copy as requested by FIXP_P.  */
            || (bit_dest == bit_src && !fixp_p))
          continue;

        if (t_bit_src != bit_src)
          {
            /* Source bit is not yet in T: Store it to T.  */
              
            t_bit_src = bit_src;

            xop[3] = GEN_INT (bit_src);
            avr_asm_len ("bst %T1%T3", xop, plen, 1);
          }

        /* Load destination bit with T.  */
        
        xop[3] = GEN_INT (bit_dest);
        avr_asm_len ("bld %T0%T3", xop, plen, 1);
      }
}


/* PLEN == 0: Print assembler code for `insert_bits'.
   PLEN != 0: Compute code length in bytes.
   
   OP[0]:  Result
   OP[1]:  The mapping composed of nibbles. If nibble no. N is
           0:   Bit N of result is copied from bit OP[2].0
           ...  ...
           7:   Bit N of result is copied from bit OP[2].7
           0xf: Bit N of result is copied from bit OP[3].N
   OP[2]:  Bits to be inserted
   OP[3]:  Target value  */

const char*
avr_out_insert_bits (rtx *op, int *plen)
{
  double_int map = rtx_to_double_int (op[1]);
  unsigned mask_fixed;
  bool fixp_p = true;
  rtx xop[4];

  xop[0] = op[0];
  xop[1] = op[2];
  xop[2] = op[3];

  gcc_assert (REG_P (xop[2]) || CONST_INT_P (xop[2]));
          
  if (plen)
    *plen = 0;
  else if (flag_print_asm_name)
    fprintf (asm_out_file,
             ASM_COMMENT_START "map = 0x%08" HOST_LONG_FORMAT "x\n",
             double_int_to_uhwi (map) & GET_MODE_MASK (SImode));

  /* If MAP has fixed points it might be better to initialize the result
     with the bits to be inserted instead of moving all bits by hand.  */
      
  mask_fixed = avr_map_metric (map, MAP_MASK_FIXED_0_7);

  if (REGNO (xop[0]) == REGNO (xop[1]))
    {
      /* Avoid early-clobber conflicts */
      
      avr_asm_len ("mov __tmp_reg__,%1", xop, plen, 1);
      xop[1] = tmp_reg_rtx;
      fixp_p = false;
    }

  if (avr_map_metric (map, MAP_MASK_PREIMAGE_F))
    {
      /* XOP[2] is used and reloaded to XOP[0] already */
      
      int n_fix = 0, n_nofix = 0;
      
      gcc_assert (REG_P (xop[2]));
      
      /* Get the code size of the bit insertions; once with all bits
         moved and once with fixed points omitted.  */
  
      avr_move_bits (xop, map, true, &n_fix);
      avr_move_bits (xop, map, false, &n_nofix);

      if (fixp_p && n_fix - n_nofix > 3)
        {
          xop[3] = gen_int_mode (~mask_fixed, QImode);
        
          avr_asm_len ("eor %0,%1"   CR_TAB
                       "andi %0,%3"  CR_TAB
                       "eor %0,%1", xop, plen, 3);
          fixp_p = false;
        }
    }
  else
    {
      /* XOP[2] is unused */
      
      if (fixp_p && mask_fixed)
        {
          avr_asm_len ("mov %0,%1", xop, plen, 1);
          fixp_p = false;
        }
    }
  
  /* Move/insert remaining bits.  */

  avr_move_bits (xop, map, fixp_p, plen);
  
  return "";
}


/* IDs for all the AVR builtins.  */

enum avr_builtin_id
  {
    AVR_BUILTIN_NOP,
    AVR_BUILTIN_SEI,
    AVR_BUILTIN_CLI,
    AVR_BUILTIN_WDR,
    AVR_BUILTIN_SLEEP,
    AVR_BUILTIN_SWAP,
    AVR_BUILTIN_INSERT_BITS,
    AVR_BUILTIN_FMUL,
    AVR_BUILTIN_FMULS,
    AVR_BUILTIN_FMULSU,
    AVR_BUILTIN_DELAY_CYCLES
  };

static void
avr_init_builtin_int24 (void)
{
  tree int24_type  = make_signed_type (GET_MODE_BITSIZE (PSImode));
  tree uint24_type = make_unsigned_type (GET_MODE_BITSIZE (PSImode));

  (*lang_hooks.types.register_builtin_type) (int24_type, "__int24");
  (*lang_hooks.types.register_builtin_type) (uint24_type, "__uint24");
}

#define DEF_BUILTIN(NAME, TYPE, CODE)                                   \
  do                                                                    \
    {                                                                   \
      add_builtin_function ((NAME), (TYPE), (CODE), BUILT_IN_MD,        \
                            NULL, NULL_TREE);                           \
    } while (0)


/* Implement `TARGET_INIT_BUILTINS' */
/* Set up all builtin functions for this target.  */

static void
avr_init_builtins (void)
{
  tree void_ftype_void
    = build_function_type_list (void_type_node, NULL_TREE);
  tree uchar_ftype_uchar
    = build_function_type_list (unsigned_char_type_node, 
                                unsigned_char_type_node,
                                NULL_TREE);
  tree uint_ftype_uchar_uchar
    = build_function_type_list (unsigned_type_node, 
                                unsigned_char_type_node,
                                unsigned_char_type_node, 
                                NULL_TREE);
  tree int_ftype_char_char
    = build_function_type_list (integer_type_node, 
                                char_type_node,
                                char_type_node, 
                                NULL_TREE);
  tree int_ftype_char_uchar
    = build_function_type_list (integer_type_node, 
                                char_type_node,
                                unsigned_char_type_node, 
                                NULL_TREE);
  tree void_ftype_ulong
    = build_function_type_list (void_type_node, 
                                long_unsigned_type_node,
                                NULL_TREE);

  tree uchar_ftype_ulong_uchar_uchar
    = build_function_type_list (unsigned_char_type_node,
                                long_unsigned_type_node,
                                unsigned_char_type_node,
                                unsigned_char_type_node,
                                NULL_TREE);

  DEF_BUILTIN ("__builtin_avr_nop", void_ftype_void, AVR_BUILTIN_NOP);
  DEF_BUILTIN ("__builtin_avr_sei", void_ftype_void, AVR_BUILTIN_SEI);
  DEF_BUILTIN ("__builtin_avr_cli", void_ftype_void, AVR_BUILTIN_CLI);
  DEF_BUILTIN ("__builtin_avr_wdr", void_ftype_void, AVR_BUILTIN_WDR);
  DEF_BUILTIN ("__builtin_avr_sleep", void_ftype_void, AVR_BUILTIN_SLEEP);
  DEF_BUILTIN ("__builtin_avr_swap", uchar_ftype_uchar, AVR_BUILTIN_SWAP);
  DEF_BUILTIN ("__builtin_avr_delay_cycles", void_ftype_ulong, 
               AVR_BUILTIN_DELAY_CYCLES);

  DEF_BUILTIN ("__builtin_avr_fmul", uint_ftype_uchar_uchar, 
               AVR_BUILTIN_FMUL);
  DEF_BUILTIN ("__builtin_avr_fmuls", int_ftype_char_char, 
               AVR_BUILTIN_FMULS);
  DEF_BUILTIN ("__builtin_avr_fmulsu", int_ftype_char_uchar, 
               AVR_BUILTIN_FMULSU);

  DEF_BUILTIN ("__builtin_avr_insert_bits", uchar_ftype_ulong_uchar_uchar,
               AVR_BUILTIN_INSERT_BITS);

  avr_init_builtin_int24 ();
}

#undef DEF_BUILTIN

struct avr_builtin_description
{
  const enum insn_code icode;
  const char *const name;
  const enum avr_builtin_id id;
};

static const struct avr_builtin_description
bdesc_1arg[] =
  {
    { CODE_FOR_rotlqi3_4, "__builtin_avr_swap", AVR_BUILTIN_SWAP }
  };

static const struct avr_builtin_description
bdesc_2arg[] =
  {
    { CODE_FOR_fmul, "__builtin_avr_fmul", AVR_BUILTIN_FMUL },
    { CODE_FOR_fmuls, "__builtin_avr_fmuls", AVR_BUILTIN_FMULS },
    { CODE_FOR_fmulsu, "__builtin_avr_fmulsu", AVR_BUILTIN_FMULSU }
  };

static const struct avr_builtin_description
bdesc_3arg[] =
  {
    { CODE_FOR_insert_bits, "__builtin_avr_insert_bits",
      AVR_BUILTIN_INSERT_BITS }
  };

/* Subroutine of avr_expand_builtin to take care of unop insns.  */

static rtx
avr_expand_unop_builtin (enum insn_code icode, tree exp,
                         rtx target)
{
  rtx pat;
  tree arg0 = CALL_EXPR_ARG (exp, 0);
  rtx op0 = expand_expr (arg0, NULL_RTX, VOIDmode, EXPAND_NORMAL);
  enum machine_mode op0mode = GET_MODE (op0);
  enum machine_mode tmode = insn_data[icode].operand[0].mode;
  enum machine_mode mode0 = insn_data[icode].operand[1].mode;

  if (! target
      || GET_MODE (target) != tmode
      || ! (*insn_data[icode].operand[0].predicate) (target, tmode))
    {
      target = gen_reg_rtx (tmode);
    }

  if (op0mode == SImode && mode0 == HImode)
    {
      op0mode = HImode;
      op0 = gen_lowpart (HImode, op0);
    }
  
  gcc_assert (op0mode == mode0 || op0mode == VOIDmode);

  if (! (*insn_data[icode].operand[1].predicate) (op0, mode0))
    op0 = copy_to_mode_reg (mode0, op0);

  pat = GEN_FCN (icode) (target, op0);
  if (! pat)
    return 0;
  
  emit_insn (pat);
  
  return target;
}


/* Subroutine of avr_expand_builtin to take care of binop insns.  */

static rtx
avr_expand_binop_builtin (enum insn_code icode, tree exp, rtx target)
{
  rtx pat;
  tree arg0 = CALL_EXPR_ARG (exp, 0);
  tree arg1 = CALL_EXPR_ARG (exp, 1);
  rtx op0 = expand_expr (arg0, NULL_RTX, VOIDmode, EXPAND_NORMAL);
  rtx op1 = expand_expr (arg1, NULL_RTX, VOIDmode, EXPAND_NORMAL);
  enum machine_mode op0mode = GET_MODE (op0);
  enum machine_mode op1mode = GET_MODE (op1);
  enum machine_mode tmode = insn_data[icode].operand[0].mode;
  enum machine_mode mode0 = insn_data[icode].operand[1].mode;
  enum machine_mode mode1 = insn_data[icode].operand[2].mode;

  if (! target
      || GET_MODE (target) != tmode
      || ! (*insn_data[icode].operand[0].predicate) (target, tmode))
    {
      target = gen_reg_rtx (tmode);
    }

  if ((op0mode == SImode || op0mode == VOIDmode) && mode0 == HImode)
    {
      op0mode = HImode;
      op0 = gen_lowpart (HImode, op0);
    }
  
  if ((op1mode == SImode || op1mode == VOIDmode) && mode1 == HImode)
    {
      op1mode = HImode;
      op1 = gen_lowpart (HImode, op1);
    }
  
  /* In case the insn wants input operands in modes different from
     the result, abort.  */
  
  gcc_assert ((op0mode == mode0 || op0mode == VOIDmode)
              && (op1mode == mode1 || op1mode == VOIDmode));

  if (! (*insn_data[icode].operand[1].predicate) (op0, mode0))
    op0 = copy_to_mode_reg (mode0, op0);
  
  if (! (*insn_data[icode].operand[2].predicate) (op1, mode1))
    op1 = copy_to_mode_reg (mode1, op1);

  pat = GEN_FCN (icode) (target, op0, op1);
  
  if (! pat)
    return 0;

  emit_insn (pat);
  return target;
}

/* Subroutine of avr_expand_builtin to take care of 3-operand insns.  */

static rtx
avr_expand_triop_builtin (enum insn_code icode, tree exp, rtx target)
{
  rtx pat;
  tree arg0 = CALL_EXPR_ARG (exp, 0);
  tree arg1 = CALL_EXPR_ARG (exp, 1);
  tree arg2 = CALL_EXPR_ARG (exp, 2);
  rtx op0 = expand_expr (arg0, NULL_RTX, VOIDmode, EXPAND_NORMAL);
  rtx op1 = expand_expr (arg1, NULL_RTX, VOIDmode, EXPAND_NORMAL);
  rtx op2 = expand_expr (arg2, NULL_RTX, VOIDmode, EXPAND_NORMAL);
  enum machine_mode op0mode = GET_MODE (op0);
  enum machine_mode op1mode = GET_MODE (op1);
  enum machine_mode op2mode = GET_MODE (op2);
  enum machine_mode tmode = insn_data[icode].operand[0].mode;
  enum machine_mode mode0 = insn_data[icode].operand[1].mode;
  enum machine_mode mode1 = insn_data[icode].operand[2].mode;
  enum machine_mode mode2 = insn_data[icode].operand[3].mode;

  if (! target
      || GET_MODE (target) != tmode
      || ! (*insn_data[icode].operand[0].predicate) (target, tmode))
    {
      target = gen_reg_rtx (tmode);
    }

  if ((op0mode == SImode || op0mode == VOIDmode) && mode0 == HImode)
    {
      op0mode = HImode;
      op0 = gen_lowpart (HImode, op0);
    }
  
  if ((op1mode == SImode || op1mode == VOIDmode) && mode1 == HImode)
    {
      op1mode = HImode;
      op1 = gen_lowpart (HImode, op1);
    }
  
  if ((op2mode == SImode || op2mode == VOIDmode) && mode2 == HImode)
    {
      op2mode = HImode;
      op2 = gen_lowpart (HImode, op2);
    }
  
  /* In case the insn wants input operands in modes different from
     the result, abort.  */
  
  gcc_assert ((op0mode == mode0 || op0mode == VOIDmode)
              && (op1mode == mode1 || op1mode == VOIDmode)
              && (op2mode == mode2 || op2mode == VOIDmode));

  if (! (*insn_data[icode].operand[1].predicate) (op0, mode0))
    op0 = copy_to_mode_reg (mode0, op0);
  
  if (! (*insn_data[icode].operand[2].predicate) (op1, mode1))
    op1 = copy_to_mode_reg (mode1, op1);

  if (! (*insn_data[icode].operand[3].predicate) (op2, mode2))
    op2 = copy_to_mode_reg (mode2, op2);

  pat = GEN_FCN (icode) (target, op0, op1, op2);
  
  if (! pat)
    return 0;

  emit_insn (pat);
  return target;
}


/* 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
avr_expand_builtin (tree exp, rtx target,
                    rtx subtarget ATTRIBUTE_UNUSED,
                    enum machine_mode mode ATTRIBUTE_UNUSED,
                    int ignore ATTRIBUTE_UNUSED)
{
  size_t i;
  const struct avr_builtin_description *d;
  tree fndecl = TREE_OPERAND (CALL_EXPR_FN (exp), 0);
  const char* bname = IDENTIFIER_POINTER (DECL_NAME (fndecl));
  unsigned int id = DECL_FUNCTION_CODE (fndecl);
  tree arg0;
  rtx op0;

  switch (id)
    {
    case AVR_BUILTIN_NOP:
      emit_insn (gen_nopv (GEN_INT(1)));
      return 0;
      
    case AVR_BUILTIN_SEI:
      emit_insn (gen_enable_interrupt ());
      return 0;
      
    case AVR_BUILTIN_CLI:
      emit_insn (gen_disable_interrupt ());
      return 0;
      
    case AVR_BUILTIN_WDR:
      emit_insn (gen_wdr ());
      return 0;
      
    case AVR_BUILTIN_SLEEP:
      emit_insn (gen_sleep ());
      return 0;
      
    case AVR_BUILTIN_DELAY_CYCLES:
      {
        arg0 = CALL_EXPR_ARG (exp, 0);
        op0 = expand_expr (arg0, NULL_RTX, VOIDmode, EXPAND_NORMAL);

        if (! CONST_INT_P (op0))
          error ("%s expects a compile time integer constant", bname);

        avr_expand_delay_cycles (op0);
        return 0;
      }

    case AVR_BUILTIN_INSERT_BITS:
      {
        arg0 = CALL_EXPR_ARG (exp, 0);
        op0 = expand_expr (arg0, NULL_RTX, VOIDmode, EXPAND_NORMAL);

        if (!CONST_INT_P (op0))
          {
            error ("%s expects a compile time long integer constant"
                   " as first argument", bname);
            return target;
          }
      }
    }

  for (i = 0, d = bdesc_1arg; i < ARRAY_SIZE (bdesc_1arg); i++, d++)
    if (d->id == id)
      return avr_expand_unop_builtin (d->icode, exp, target);

  for (i = 0, d = bdesc_2arg; i < ARRAY_SIZE (bdesc_2arg); i++, d++)
    if (d->id == id)
      return avr_expand_binop_builtin (d->icode, exp, target);

  for (i = 0, d = bdesc_3arg; i < ARRAY_SIZE (bdesc_3arg); i++, d++)
    if (d->id == id)
      return avr_expand_triop_builtin (d->icode, exp, target);

  gcc_unreachable ();
}


/* Implement `TARGET_FOLD_BUILTIN'.  */

static tree
avr_fold_builtin (tree fndecl, int n_args ATTRIBUTE_UNUSED, tree *arg,
                  bool ignore ATTRIBUTE_UNUSED)
{
  unsigned int fcode = DECL_FUNCTION_CODE (fndecl);
  tree val_type = TREE_TYPE (TREE_TYPE (fndecl));

  if (!optimize)
    return NULL_TREE;
  
  switch (fcode)
    {
    default:
      break;

    case AVR_BUILTIN_INSERT_BITS:
      {
        tree tbits = arg[1];
        tree tval = arg[2];
        tree tmap;
        tree map_type = TREE_VALUE (TYPE_ARG_TYPES (TREE_TYPE (fndecl)));
        double_int map = tree_to_double_int (arg[0]);
        bool changed = false;
        unsigned i;
        avr_map_op_t best_g;
        
        tmap = double_int_to_tree (map_type, map);

        if (TREE_CODE (tval) != INTEGER_CST
            && 0 == avr_map_metric (map, MAP_MASK_PREIMAGE_F))
          {
            /* There are no F in the map, i.e. 3rd operand is unused.
               Replace that argument with some constant to render
               respective input unused.  */
            
            tval = build_int_cst (val_type, 0);
            changed = true;
          }

        if (TREE_CODE (tbits) != INTEGER_CST
            && 0 == avr_map_metric (map, MAP_PREIMAGE_0_7))
          {
            /* Similar for the bits to be inserted. If they are unused,
               we can just as well pass 0.  */
            
            tbits = build_int_cst (val_type, 0);
          }

        if (TREE_CODE (tbits) == INTEGER_CST)
          {
            /* Inserting bits known at compile time is easy and can be
               performed by AND and OR with appropriate masks.  */

            int bits = TREE_INT_CST_LOW (tbits);
            int mask_ior = 0, mask_and = 0xff;

            for (i = 0; i < 8; i++)
              {
                int mi = avr_map (map, i);

                if (mi < 8)
                  {
                    if (bits & (1 << mi))     mask_ior |=  (1 << i);
                    else                      mask_and &= ~(1 << i);
                  }
              }

            tval = fold_build2 (BIT_IOR_EXPR, val_type, tval,
                                build_int_cst (val_type, mask_ior));
            return fold_build2 (BIT_AND_EXPR, val_type, tval,
                                build_int_cst (val_type, mask_and));
          }

        if (changed)
          return build_call_expr (fndecl, 3, tmap, tbits, tval);

        /* If bits don't change their position we can use vanilla logic
           to merge the two arguments.  */

        if (0 == avr_map_metric (map, MAP_NONFIXED_0_7))
          {
            int mask_f = avr_map_metric (map, MAP_MASK_PREIMAGE_F);
            tree tres, tmask = build_int_cst (val_type, mask_f ^ 0xff);

            tres = fold_build2 (BIT_XOR_EXPR, val_type, tbits, tval);
            tres = fold_build2 (BIT_AND_EXPR, val_type, tres, tmask);
            return fold_build2 (BIT_XOR_EXPR, val_type, tres, tval);
          }

        /* Try to decomposing map to reduce overall cost.  */

        if (avr_log.builtin)
          avr_edump ("\n%?: %X\n%?: ROL cost: ", map);
        
        best_g = avr_map_op[0];
        best_g.cost = 1000;
        
        for (i = 0; i < sizeof (avr_map_op) / sizeof (*avr_map_op); i++)
          {
            avr_map_op_t g
              = avr_map_decompose (map, avr_map_op + i,
                                   TREE_CODE (tval) == INTEGER_CST);

            if (g.cost >= 0 && g.cost < best_g.cost)
              best_g = g;
          }

        if (avr_log.builtin)
          avr_edump ("\n");
                     
        if (best_g.arg == 0)
          /* No optimization found */
          break;
        
        /* Apply operation G to the 2nd argument.  */
              
        if (avr_log.builtin)
          avr_edump ("%?: using OP(%s%d, %X) cost %d\n",
                     best_g.str, best_g.arg, best_g.map, best_g.cost);

        /* Do right-shifts arithmetically: They copy the MSB instead of
           shifting in a non-usable value (0) as with logic right-shift.  */
        
        tbits = fold_convert (signed_char_type_node, tbits);
        tbits = fold_build2 (best_g.code, signed_char_type_node, tbits,
                             build_int_cst (val_type, best_g.arg));
        tbits = fold_convert (val_type, tbits);

        /* Use map o G^-1 instead of original map to undo the effect of G.  */
        
        tmap = double_int_to_tree (map_type, best_g.map);
        
        return build_call_expr (fndecl, 3, tmap, tbits, tval);
      } /* AVR_BUILTIN_INSERT_BITS */
    }

  return NULL_TREE;
}


\f
struct gcc_target targetm = TARGET_INITIALIZER;

#include "gt-avr.h"