[gcc.git] / gcc / config / vax / vax.cc

/* Subroutines for insn-output.cc for VAX.
   Copyright (C) 1987-2023 Free Software Foundation, Inc.

This file is part of GCC.

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

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

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

#define IN_TARGET_CODE 1

#include "config.h"
#include "system.h"
#include "coretypes.h"
#include "backend.h"
#include "target.h"
#include "rtl.h"
#include "tree.h"
#include "stringpool.h"
#include "attribs.h"
#include "df.h"
#include "memmodel.h"
#include "tm_p.h"
#include "optabs.h"
#include "regs.h"
#include "emit-rtl.h"
#include "calls.h"
#include "varasm.h"
#include "conditions.h"
#include "output.h"
#include "expr.h"
#include "reload.h"
#include "builtins.h"

/* This file should be included last.  */
#include "target-def.h"

static void vax_option_override (void);
static bool vax_legitimate_address_p (machine_mode, rtx, bool,
                                      code_helper = ERROR_MARK);
static void vax_file_start (void);
static void vax_init_libfuncs (void);
static void vax_output_mi_thunk (FILE *, tree, HOST_WIDE_INT,
                                 HOST_WIDE_INT, tree);
static int vax_address_cost_1 (rtx);
static int vax_address_cost (rtx, machine_mode, addr_space_t, bool);
static bool vax_rtx_costs (rtx, machine_mode, int, int, int *, bool);
static machine_mode vax_cc_modes_compatible (machine_mode, machine_mode);
static rtx_insn *vax_md_asm_adjust (vec<rtx> &, vec<rtx> &,
                                    vec<machine_mode> &, vec<const char *> &,
                                    vec<rtx> &, HARD_REG_SET &, location_t);
static rtx vax_function_arg (cumulative_args_t, const function_arg_info &);
static void vax_function_arg_advance (cumulative_args_t,
                                      const function_arg_info &);
static rtx vax_struct_value_rtx (tree, int);
static bool vax_lra_p (void);
static void vax_asm_trampoline_template (FILE *);
static void vax_trampoline_init (rtx, tree, rtx);
static poly_int64 vax_return_pops_args (tree, tree, poly_int64);
static bool vax_mode_dependent_address_p (const_rtx, addr_space_t);
static HOST_WIDE_INT vax_starting_frame_offset (void);
\f
/* Initialize the GCC target structure.  */
#undef TARGET_ASM_ALIGNED_HI_OP
#define TARGET_ASM_ALIGNED_HI_OP "\t.word\t"

#undef TARGET_ASM_FILE_START
#define TARGET_ASM_FILE_START vax_file_start
#undef TARGET_ASM_FILE_START_APP_OFF
#define TARGET_ASM_FILE_START_APP_OFF true

#undef TARGET_INIT_LIBFUNCS
#define TARGET_INIT_LIBFUNCS vax_init_libfuncs

#undef TARGET_ASM_OUTPUT_MI_THUNK
#define TARGET_ASM_OUTPUT_MI_THUNK vax_output_mi_thunk
#undef TARGET_ASM_CAN_OUTPUT_MI_THUNK
#define TARGET_ASM_CAN_OUTPUT_MI_THUNK default_can_output_mi_thunk_no_vcall

/* Enable compare elimination pass.  */
#undef TARGET_FLAGS_REGNUM
#define TARGET_FLAGS_REGNUM VAX_PSL_REGNUM

#undef TARGET_RTX_COSTS
#define TARGET_RTX_COSTS vax_rtx_costs
#undef TARGET_ADDRESS_COST
#define TARGET_ADDRESS_COST vax_address_cost

/* Return the narrowest CC mode that spans both modes offered.  */
#undef TARGET_CC_MODES_COMPATIBLE
#define TARGET_CC_MODES_COMPATIBLE vax_cc_modes_compatible

/* Mark PSL as clobbered for compatibility with the CC0 representation.  */
#undef TARGET_MD_ASM_ADJUST
#define TARGET_MD_ASM_ADJUST vax_md_asm_adjust

#undef TARGET_PROMOTE_PROTOTYPES
#define TARGET_PROMOTE_PROTOTYPES hook_bool_const_tree_true

#undef TARGET_FUNCTION_ARG
#define TARGET_FUNCTION_ARG vax_function_arg
#undef TARGET_FUNCTION_ARG_ADVANCE
#define TARGET_FUNCTION_ARG_ADVANCE vax_function_arg_advance

#undef TARGET_STRUCT_VALUE_RTX
#define TARGET_STRUCT_VALUE_RTX vax_struct_value_rtx

#undef TARGET_LRA_P
#define TARGET_LRA_P vax_lra_p

#undef TARGET_LEGITIMATE_ADDRESS_P
#define TARGET_LEGITIMATE_ADDRESS_P vax_legitimate_address_p
#undef TARGET_MODE_DEPENDENT_ADDRESS_P
#define TARGET_MODE_DEPENDENT_ADDRESS_P vax_mode_dependent_address_p

#undef TARGET_FRAME_POINTER_REQUIRED
#define TARGET_FRAME_POINTER_REQUIRED hook_bool_void_true

#undef TARGET_ASM_TRAMPOLINE_TEMPLATE
#define TARGET_ASM_TRAMPOLINE_TEMPLATE vax_asm_trampoline_template
#undef TARGET_TRAMPOLINE_INIT
#define TARGET_TRAMPOLINE_INIT vax_trampoline_init
#undef TARGET_RETURN_POPS_ARGS
#define TARGET_RETURN_POPS_ARGS vax_return_pops_args

#undef TARGET_OPTION_OVERRIDE
#define TARGET_OPTION_OVERRIDE vax_option_override

#undef TARGET_STARTING_FRAME_OFFSET
#define TARGET_STARTING_FRAME_OFFSET vax_starting_frame_offset

#undef TARGET_HAVE_SPECULATION_SAFE_VALUE
#define TARGET_HAVE_SPECULATION_SAFE_VALUE speculation_safe_value_not_needed

struct gcc_target targetm = TARGET_INITIALIZER;
\f
/* Set global variables as needed for the options enabled.  */

static void
vax_option_override (void)
{
  /* We're VAX floating point, not IEEE floating point.  */
  if (TARGET_G_FLOAT)
    REAL_MODE_FORMAT (DFmode) = &vax_g_format;

#ifdef SUBTARGET_OVERRIDE_OPTIONS
  SUBTARGET_OVERRIDE_OPTIONS;
#endif
}

static void
vax_add_reg_cfa_offset (rtx insn, int offset, rtx src)
{
  rtx x;

  x = plus_constant (Pmode, frame_pointer_rtx, offset);
  x = gen_rtx_MEM (SImode, x);
  x = gen_rtx_SET (x, src);
  add_reg_note (insn, REG_CFA_OFFSET, x);
}

/* Generate the assembly code for function entry.  FILE is a stdio
   stream to output the code to.  SIZE is an int: how many units of
   temporary storage to allocate.

   Refer to the array `regs_ever_live' to determine which registers to
   save; `regs_ever_live[I]' is nonzero if register number I is ever
   used in the function.  This function is responsible for knowing
   which registers should not be saved even if used.  */

void
vax_expand_prologue (void)
{
  int regno, offset;
  int mask = 0;
  HOST_WIDE_INT size;
  rtx insn;

  for (regno = 0; regno < FIRST_PSEUDO_REGISTER; regno++)
    if (df_regs_ever_live_p (regno) && !call_used_or_fixed_reg_p (regno))
      mask |= 1 << regno;

  insn = emit_insn (gen_procedure_entry_mask (GEN_INT (mask)));
  RTX_FRAME_RELATED_P (insn) = 1;

  /* The layout of the CALLG/S stack frame is follows:

                <- CFA, AP
        r11
        r10
        ...     Registers saved as specified by MASK
        r3
        r2
        return-addr
        old fp
        old ap
        old psw
        zero
                <- FP, SP

     The rest of the prologue will adjust the SP for the local frame.  */

  vax_add_reg_cfa_offset (insn, 4, arg_pointer_rtx);
  vax_add_reg_cfa_offset (insn, 8, frame_pointer_rtx);
  vax_add_reg_cfa_offset (insn, 12, pc_rtx);

  offset = 16;
  for (regno = 0; regno < FIRST_PSEUDO_REGISTER; regno++)
    if (mask & (1 << regno))
      {
        vax_add_reg_cfa_offset (insn, offset, gen_rtx_REG (SImode, regno));
        offset += 4;
      }

  /* Because add_reg_note pushes the notes, adding this last means that
     it will be processed first.  This is required to allow the other
     notes be interpreted properly.  */
  add_reg_note (insn, REG_CFA_DEF_CFA,
                plus_constant (Pmode, frame_pointer_rtx, offset));

  /* Allocate the local stack frame.  */
  size = get_frame_size ();
  size -= vax_starting_frame_offset ();
  emit_insn (gen_addsi3 (stack_pointer_rtx,
                         stack_pointer_rtx, GEN_INT (-size)));

  /* Do not allow instructions referencing local stack memory to be
     scheduled before the frame is allocated.  This is more pedantic
     than anything else, given that VAX does not currently have a
     scheduling description.  */
  emit_insn (gen_blockage ());
}

/* When debugging with stabs, we want to output an extra dummy label
   so that gas can distinguish between D_float and G_float prior to
   processing the .stabs directive identifying type double.  */
static void
vax_file_start (void)
{
  default_file_start ();
}

/* We can use the BSD C library routines for the libgcc calls that are
   still generated, since that's what they boil down to anyways.  When
   ELF, avoid the user's namespace.  */

static void
vax_init_libfuncs (void)
{
  if (TARGET_BSD_DIVMOD)
    {
      set_optab_libfunc (udiv_optab, SImode, TARGET_ELF ? "*__udiv" : "*udiv");
      set_optab_libfunc (umod_optab, SImode, TARGET_ELF ? "*__urem" : "*urem");
    }
}

/* This is like nonimmediate_operand with a restriction on the type of MEM.  */

static void
split_quadword_operands (rtx insn, enum rtx_code code, rtx * operands,
                         rtx * low, int n)
{
  int i;

  for (i = 0; i < n; i++)
    low[i] = 0;

  for (i = 0; i < n; i++)
    {
      if (MEM_P (operands[i])
          && (GET_CODE (XEXP (operands[i], 0)) == PRE_DEC
              || GET_CODE (XEXP (operands[i], 0)) == POST_INC))
        {
          rtx addr = XEXP (operands[i], 0);
          operands[i] = low[i] = gen_rtx_MEM (SImode, addr);
        }
      else if (optimize_size && MEM_P (operands[i])
               && REG_P (XEXP (operands[i], 0))
               && (code != MINUS || operands[1] != const0_rtx)
               && find_regno_note (insn, REG_DEAD,
                                   REGNO (XEXP (operands[i], 0))))
        {
          low[i] = gen_rtx_MEM (SImode,
                                gen_rtx_POST_INC (Pmode,
                                                  XEXP (operands[i], 0)));
          operands[i] = gen_rtx_MEM (SImode, XEXP (operands[i], 0));
        }
      else
        {
          low[i] = operand_subword (operands[i], 0, 0, DImode);
          operands[i] = operand_subword (operands[i], 1, 0, DImode);
        }
    }
}
\f
void
print_operand_address (FILE * file, rtx addr)
{
  rtx orig = addr;
  rtx reg1, breg, ireg;
  rtx offset;

 retry:
  switch (GET_CODE (addr))
    {
    case MEM:
      fprintf (file, "*");
      addr = XEXP (addr, 0);
      goto retry;

    case REG:
      fprintf (file, "(%s)", reg_names[REGNO (addr)]);
      break;

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

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

    case PLUS:
      /* There can be either two or three things added here.  One must be a
         REG.  One can be either a REG or a MULT/ASHIFT of a REG and an
         appropriate constant, and the third can only be a constant or a MEM.

         We get these two or three things and put the constant or MEM in
         OFFSET, the MULT/ASHIFT or REG in IREG, and the REG in BREG.  If we
         have a register and can't tell yet if it is a base or index register,
         put it into REG1.  */

      reg1 = 0; ireg = 0; breg = 0; offset = 0;

      if (CONSTANT_ADDRESS_P (XEXP (addr, 0))
          || MEM_P (XEXP (addr, 0)))
        {
          offset = XEXP (addr, 0);
          addr = XEXP (addr, 1);
        }
      else if (CONSTANT_ADDRESS_P (XEXP (addr, 1))
               || MEM_P (XEXP (addr, 1)))
        {
          offset = XEXP (addr, 1);
          addr = XEXP (addr, 0);
        }
      else if (GET_CODE (XEXP (addr, 1)) == MULT
               || GET_CODE (XEXP (addr, 1)) == ASHIFT)
        {
          ireg = XEXP (addr, 1);
          addr = XEXP (addr, 0);
        }
      else if (GET_CODE (XEXP (addr, 0)) == MULT
               || GET_CODE (XEXP (addr, 0)) == ASHIFT)
        {
          ireg = XEXP (addr, 0);
          addr = XEXP (addr, 1);
        }
      else if (REG_P (XEXP (addr, 1)))
        {
          reg1 = XEXP (addr, 1);
          addr = XEXP (addr, 0);
        }
      else if (REG_P (XEXP (addr, 0)))
        {
          reg1 = XEXP (addr, 0);
          addr = XEXP (addr, 1);
        }
      else
        gcc_unreachable ();

      if (REG_P (addr))
        {
          if (reg1)
            ireg = addr;
          else
            reg1 = addr;
        }
      else if (GET_CODE (addr) == MULT || GET_CODE (addr) == ASHIFT)
        ireg = addr;
      else
        {
          gcc_assert (GET_CODE (addr) == PLUS);
          if (CONSTANT_ADDRESS_P (XEXP (addr, 0))
              || MEM_P (XEXP (addr, 0)))
            {
              if (offset)
                {
                  if (CONST_INT_P (offset))
                    offset = plus_constant (Pmode, XEXP (addr, 0),
                                            INTVAL (offset));
                  else
                    {
                      gcc_assert (CONST_INT_P (XEXP (addr, 0)));
                      offset = plus_constant (Pmode, offset,
                                              INTVAL (XEXP (addr, 0)));
                    }
                }
              offset = XEXP (addr, 0);
            }
          else if (REG_P (XEXP (addr, 0)))
            {
              if (reg1)
                ireg = reg1, breg = XEXP (addr, 0), reg1 = 0;
              else
                reg1 = XEXP (addr, 0);
            }
          else
            {
              gcc_assert (GET_CODE (XEXP (addr, 0)) == MULT
                          || GET_CODE (XEXP (addr, 0)) == ASHIFT);
              gcc_assert (!ireg);
              ireg = XEXP (addr, 0);
            }

          if (CONSTANT_ADDRESS_P (XEXP (addr, 1))
              || MEM_P (XEXP (addr, 1)))
            {
              if (offset)
                {
                  if (CONST_INT_P (offset))
                    offset = plus_constant (Pmode, XEXP (addr, 1),
                                            INTVAL (offset));
                  else
                    {
                      gcc_assert (CONST_INT_P (XEXP (addr, 1)));
                      offset = plus_constant (Pmode, offset,
                                              INTVAL (XEXP (addr, 1)));
                    }
                }
              offset = XEXP (addr, 1);
            }
          else if (REG_P (XEXP (addr, 1)))
            {
              if (reg1)
                ireg = reg1, breg = XEXP (addr, 1), reg1 = 0;
              else
                reg1 = XEXP (addr, 1);
            }
          else
            {
              gcc_assert (GET_CODE (XEXP (addr, 1)) == MULT
                          || GET_CODE (XEXP (addr, 1)) == ASHIFT);
              gcc_assert (!ireg);
              ireg = XEXP (addr, 1);
            }
        }

      /* If REG1 is nonzero, figure out if it is a base or index register.  */
      if (reg1)
        {
          if (breg
              || (flag_pic && GET_CODE (addr) == SYMBOL_REF)
              || (offset
                  && (MEM_P (offset)
                      || (flag_pic && symbolic_operand (offset, SImode)))))
            {
              gcc_assert (!ireg);
              ireg = reg1;
            }
          else
            breg = reg1;
        }

      if (offset != 0)
        {
          if (flag_pic && symbolic_operand (offset, SImode))
            {
              if (breg && ireg)
                {
                  debug_rtx (orig);
                  output_operand_lossage ("symbol used with both base and indexed registers");
                }

#ifdef NO_EXTERNAL_INDIRECT_ADDRESS
              if (flag_pic > 1 && GET_CODE (offset) == CONST
                  && GET_CODE (XEXP (XEXP (offset, 0), 0)) == SYMBOL_REF
                  && !SYMBOL_REF_LOCAL_P (XEXP (XEXP (offset, 0), 0)))
                {
                  debug_rtx (orig);
                  output_operand_lossage ("symbol with offset used in PIC mode");
                }
#endif

              /* symbol(reg) isn't PIC, but symbol[reg] is.  */
              if (breg)
                {
                  ireg = breg;
                  breg = 0;
                }

            }

          output_address (VOIDmode, offset);
        }

      if (breg != 0)
        fprintf (file, "(%s)", reg_names[REGNO (breg)]);

      if (ireg != 0)
        {
          if (GET_CODE (ireg) == MULT || GET_CODE (ireg) == ASHIFT)
            ireg = XEXP (ireg, 0);
          gcc_assert (REG_P (ireg));
          fprintf (file, "[%s]", reg_names[REGNO (ireg)]);
        }
      break;

    default:
      output_addr_const (file, addr);
    }
}

void
print_operand (FILE *file, rtx x, int code)
{
  if (code == '#')
    fputc (ASM_DOUBLE_CHAR, file);
  else if (code == '|')
    fputs (REGISTER_PREFIX, file);
  else if (code == 'k')
    fputs (cond_name (x), file);
  else if (code == 'K')
    fputs (rev_cond_name (x), file);
  else if (code == 'D' && CONST_INT_P (x) && INTVAL (x) < 0)
    fprintf (file, "$" NEG_HWI_PRINT_HEX16, INTVAL (x));
  else if (code == 'P' && CONST_INT_P (x))
    fprintf (file, "$" HOST_WIDE_INT_PRINT_DEC, INTVAL (x) + 1);
  else if (code == 'N' && CONST_INT_P (x))
    fprintf (file, "$" HOST_WIDE_INT_PRINT_DEC, ~ INTVAL (x));
  /* rotl instruction cannot deal with negative arguments.  */
  else if (code == 'R' && CONST_INT_P (x))
    fprintf (file, "$" HOST_WIDE_INT_PRINT_DEC, 32 - INTVAL (x));
  else if (code == 'H' && CONST_INT_P (x))
    fprintf (file, "$%d", (int) (0xffff & ~ INTVAL (x)));
  else if (code == 'h' && CONST_INT_P (x))
    fprintf (file, "$%d", (short) - INTVAL (x));
  else if (code == 'B' && CONST_INT_P (x))
    fprintf (file, "$%d", (int) (0xff & ~ INTVAL (x)));
  else if (code == 'b' && CONST_INT_P (x))
    fprintf (file, "$%d", (int) (0xff & - INTVAL (x)));
  else if (code == 'M' && CONST_INT_P (x))
    fprintf (file, "$%d", ~((1 << INTVAL (x)) - 1));
  else if (code == 'x' && CONST_INT_P (x))
    fprintf (file, HOST_WIDE_INT_PRINT_HEX, INTVAL (x));
  else if (REG_P (x))
    fprintf (file, "%s", reg_names[REGNO (x)]);
  else if (MEM_P (x))
    output_address (GET_MODE (x), XEXP (x, 0));
  else if (GET_CODE (x) == CONST_DOUBLE && GET_MODE (x) == SFmode)
    {
      char dstr[30];
      real_to_decimal (dstr, CONST_DOUBLE_REAL_VALUE (x),
                       sizeof (dstr), 0, 1);
      fprintf (file, "$0f%s", dstr);
    }
  else if (GET_CODE (x) == CONST_DOUBLE && GET_MODE (x) == DFmode)
    {
      char dstr[30];
      real_to_decimal (dstr, CONST_DOUBLE_REAL_VALUE (x),
                       sizeof (dstr), 0, 1);
      fprintf (file, "$0%c%s", ASM_DOUBLE_CHAR, dstr);
    }
  else
    {
      if (flag_pic > 1 && symbolic_operand (x, SImode))
        {
          debug_rtx (x);
          output_operand_lossage ("symbol used as immediate operand");
        }
      putc ('$', file);
      output_addr_const (file, x);
    }
}
\f
const char *
cond_name (rtx op)
{
  switch (GET_CODE (op))
    {
    case NE:
      return "neq";
    case EQ:
      return "eql";
    case GE:
      return "geq";
    case GT:
      return "gtr";
    case LE:
      return "leq";
    case LT:
      return "lss";
    case GEU:
      return "gequ";
    case GTU:
      return "gtru";
    case LEU:
      return "lequ";
    case LTU:
      return "lssu";

    default:
      gcc_unreachable ();
    }
}

const char *
rev_cond_name (rtx op)
{
  switch (GET_CODE (op))
    {
    case EQ:
      return "neq";
    case NE:
      return "eql";
    case LT:
      return "geq";
    case LE:
      return "gtr";
    case GT:
      return "leq";
    case GE:
      return "lss";
    case LTU:
      return "gequ";
    case LEU:
      return "gtru";
    case GTU:
      return "lequ";
    case GEU:
      return "lssu";

    default:
      gcc_unreachable ();
    }
}

static bool
vax_float_literal (rtx c)
{
  machine_mode mode;
  const REAL_VALUE_TYPE *r;
  REAL_VALUE_TYPE s;
  int i;

  if (GET_CODE (c) != CONST_DOUBLE)
    return false;

  mode = GET_MODE (c);

  if (c == const_tiny_rtx[(int) mode][0]
      || c == const_tiny_rtx[(int) mode][1]
      || c == const_tiny_rtx[(int) mode][2])
    return true;

  r = CONST_DOUBLE_REAL_VALUE (c);

  for (i = 0; i < 7; i++)
    {
      int x = 1 << i;
      bool ok;
      real_from_integer (&s, mode, x, SIGNED);

      if (real_equal (r, &s))
        return true;
      ok = exact_real_inverse (mode, &s);
      gcc_assert (ok);
      if (real_equal (r, &s))
        return true;
    }
  return false;
}


/* Return the cost in cycles of a memory address, relative to register
   indirect.

   Each of the following adds the indicated number of cycles:

   1 - symbolic address
   1 - pre-decrement
   1 - indexing and/or offset(register)
   2 - indirect */


static int
vax_address_cost_1 (rtx addr)
{
  int reg = 0, indexed = 0, indir = 0, offset = 0, predec = 0;
  rtx plus_op0 = 0, plus_op1 = 0;
 restart:
  switch (GET_CODE (addr))
    {
    case PRE_DEC:
      predec = 1;
      /* FALLTHRU */
    case REG:
    case SUBREG:
    case POST_INC:
      reg = 1;
      break;
    case MULT:
    case ASHIFT:
      indexed = 1;      /* 2 on VAX 2 */
      break;
    case CONST_INT:
      /* byte offsets cost nothing (on a VAX 2, they cost 1 cycle) */
      if (offset == 0)
        offset = (unsigned HOST_WIDE_INT)(INTVAL(addr)+128) > 256;
      break;
    case CONST:
    case SYMBOL_REF:
      offset = 1;       /* 2 on VAX 2 */
      break;
    case LABEL_REF:     /* this is probably a byte offset from the pc */
      if (offset == 0)
        offset = 1;
      break;
    case PLUS:
      if (plus_op0)
        plus_op1 = XEXP (addr, 0);
      else
        plus_op0 = XEXP (addr, 0);
      addr = XEXP (addr, 1);
      goto restart;
    case MEM:
      indir = 2;        /* 3 on VAX 2 */
      addr = XEXP (addr, 0);
      goto restart;
    default:
      break;
    }

  /* Up to 3 things can be added in an address.  They are stored in
     plus_op0, plus_op1, and addr.  */

  if (plus_op0)
    {
      addr = plus_op0;
      plus_op0 = 0;
      goto restart;
    }
  if (plus_op1)
    {
      addr = plus_op1;
      plus_op1 = 0;
      goto restart;
    }
  /* Indexing and register+offset can both be used (except on a VAX 2)
     without increasing execution time over either one alone.  */
  if (reg && indexed && offset)
    return reg + indir + offset + predec;
  return reg + indexed + indir + offset + predec;
}

static int
vax_address_cost (rtx x, machine_mode mode ATTRIBUTE_UNUSED,
                  addr_space_t as ATTRIBUTE_UNUSED,
                  bool speed ATTRIBUTE_UNUSED)
{
  return COSTS_N_INSNS (1 + (REG_P (x) ? 0 : vax_address_cost_1 (x)));
}

/* Cost of an expression on a VAX.  This version has costs tuned for the
   CVAX chip (found in the VAX 3 series) with comments for variations on
   other models.

   FIXME: The costs need review, particularly for TRUNCATE, FLOAT_EXTEND
   and FLOAT_TRUNCATE.  We need a -mcpu option to allow provision of
   costs on a per cpu basis.  */

static bool
vax_rtx_costs (rtx x, machine_mode mode, int outer_code,
               int opno ATTRIBUTE_UNUSED,
               int *total, bool speed ATTRIBUTE_UNUSED)
{
  enum rtx_code code = GET_CODE (x);
  int i = 0;                               /* may be modified in switch */
  const char *fmt = GET_RTX_FORMAT (code); /* may be modified in switch */

  switch (code)
    {
      /* On a VAX, constants from 0..63 are cheap because they can use the
         1 byte literal constant format.  Compare to -1 should be made cheap
         so that decrement-and-branch insns can be formed more easily (if
         the value -1 is copied to a register some decrement-and-branch
         patterns will not match).  */
    case CONST_INT:
      if (INTVAL (x) == 0)
        {
          *total = COSTS_N_INSNS (1) / 2;
          return true;
        }
      if (outer_code == AND)
        {
          *total = ((unsigned HOST_WIDE_INT) ~INTVAL (x) <= 077
                    ? COSTS_N_INSNS (1) : COSTS_N_INSNS (2));
          return true;
        }
      if ((unsigned HOST_WIDE_INT) INTVAL (x) <= 077
          || (outer_code == COMPARE
              && INTVAL (x) == -1)
          || ((outer_code == PLUS || outer_code == MINUS)
              && (unsigned HOST_WIDE_INT) -INTVAL (x) <= 077))
        {
          *total = COSTS_N_INSNS (1);
          return true;
        }
      /* FALLTHRU */

    case CONST:
    case LABEL_REF:
    case SYMBOL_REF:
      *total = COSTS_N_INSNS (3);
      return true;

    case CONST_DOUBLE:
      if (GET_MODE_CLASS (mode) == MODE_FLOAT)
        *total = vax_float_literal (x) ? COSTS_N_INSNS (5) : COSTS_N_INSNS (8);
      else
        *total = ((CONST_DOUBLE_HIGH (x) == 0
                   && (unsigned HOST_WIDE_INT) CONST_DOUBLE_LOW (x) < 64)
                  || (outer_code == PLUS
                      && CONST_DOUBLE_HIGH (x) == -1
                      && (unsigned HOST_WIDE_INT)-CONST_DOUBLE_LOW (x) < 64)
                  ? COSTS_N_INSNS (2) : COSTS_N_INSNS (5));
      return true;

    case POST_INC:
      *total = COSTS_N_INSNS (2);
      return true;                      /* Implies register operand.  */

    case PRE_DEC:
      *total = COSTS_N_INSNS (3);
      return true;                      /* Implies register operand.  */

    case MULT:
      switch (mode)
        {
        case E_DFmode:
          *total = COSTS_N_INSNS (16);  /* 4 on VAX 9000 */
          break;
        case E_SFmode:
          *total = COSTS_N_INSNS (9);   /* 4 on VAX 9000, 12 on VAX 2 */
          break;
        case E_DImode:
          *total = COSTS_N_INSNS (16);  /* 6 on VAX 9000, 28 on VAX 2 */
          break;
        case E_SImode:
        case E_HImode:
        case E_QImode:
          *total = COSTS_N_INSNS (10);  /* 3-4 on VAX 9000, 20-28 on VAX 2 */
          break;
        default:
          *total = MAX_COST;            /* Mode is not supported.  */
          return true;
        }
      break;

    case UDIV:
      if (mode != SImode)
        {
          *total = MAX_COST;            /* Mode is not supported.  */
          return true;
        }
      *total = COSTS_N_INSNS (17);
      break;

    case DIV:
      if (mode == DImode)
        *total = COSTS_N_INSNS (30);    /* Highly variable.  */
      else if (mode == DFmode)
        /* divide takes 28 cycles if the result is not zero, 13 otherwise */
        *total = COSTS_N_INSNS (24);
      else
        *total = COSTS_N_INSNS (11);    /* 25 on VAX 2 */
      break;

    case MOD:
      *total = COSTS_N_INSNS (23);
      break;

    case UMOD:
      if (mode != SImode)
        {
          *total = MAX_COST;            /* Mode is not supported.  */
          return true;
        }
      *total = COSTS_N_INSNS (29);
      break;

    case FLOAT:
      *total = COSTS_N_INSNS (6         /* 4 on VAX 9000 */
                              + (mode == DFmode)
                              + (GET_MODE (XEXP (x, 0)) != SImode));
      break;

    case FIX:
      *total = COSTS_N_INSNS (7);       /* 17 on VAX 2 */
      break;

    case ASHIFT:
    case LSHIFTRT:
    case ASHIFTRT:
      if (mode == DImode)
        *total = COSTS_N_INSNS (12);
      else
        *total = COSTS_N_INSNS (10);    /* 6 on VAX 9000 */
      break;

    case ROTATE:
    case ROTATERT:
      *total = COSTS_N_INSNS (6);       /* 5 on VAX 2, 4 on VAX 9000 */
      if (CONST_INT_P (XEXP (x, 1)))
        fmt = "e";              /* all constant rotate counts are short */
      break;

    case PLUS:
    case MINUS:
      *total = (mode == DFmode          /* 6/8 on VAX 9000, 16/15 on VAX 2 */
                ? COSTS_N_INSNS (13) : COSTS_N_INSNS (8));
      /* Small integer operands can use subl2 and addl2.  */
      if ((CONST_INT_P (XEXP (x, 1)))
          && (unsigned HOST_WIDE_INT)(INTVAL (XEXP (x, 1)) + 63) < 127)
        fmt = "e";
      break;

    case IOR:
    case XOR:
      *total = COSTS_N_INSNS (3);
      break;

    case AND:
      /* AND is special because the first operand is complemented.  */
      *total = COSTS_N_INSNS (3);
      if (CONST_INT_P (XEXP (x, 0)))
        {
          if ((unsigned HOST_WIDE_INT)~INTVAL (XEXP (x, 0)) > 63)
            *total = COSTS_N_INSNS (4);
          fmt = "e";
          i = 1;
        }
      break;

    case NEG:
      if (mode == DFmode)
        *total = COSTS_N_INSNS (9);
      else if (mode == SFmode)
        *total = COSTS_N_INSNS (6);
      else if (mode == DImode)
        *total = COSTS_N_INSNS (4);
      else
        *total = COSTS_N_INSNS (2);
      break;

    case NOT:
      *total = COSTS_N_INSNS (2);
      break;

    case ZERO_EXTRACT:
    case SIGN_EXTRACT:
      *total = COSTS_N_INSNS (15);
      break;

    case MEM:
      if (mode == DImode || mode == DFmode)
        *total = COSTS_N_INSNS (5);     /* 7 on VAX 2 */
      else
        *total = COSTS_N_INSNS (3);     /* 4 on VAX 2 */
      x = XEXP (x, 0);
      if (!REG_P (x) && GET_CODE (x) != POST_INC)
        *total += COSTS_N_INSNS (vax_address_cost_1 (x));
      return true;

    case FLOAT_EXTEND:
    case FLOAT_TRUNCATE:
    case TRUNCATE:
      *total = COSTS_N_INSNS (3);       /* FIXME: Costs need to be checked  */
      break;

    default:
      return false;
    }

  /* Now look inside the expression.  Operands which are not registers or
     short constants add to the cost.

     FMT and I may have been adjusted in the switch above for instructions
     which require special handling.  */

  while (*fmt++ == 'e')
    {
      rtx op = XEXP (x, i);

      i += 1;
      code = GET_CODE (op);

      /* A NOT is likely to be found as the first operand of an AND
         (in which case the relevant cost is of the operand inside
         the not) and not likely to be found anywhere else.  */
      if (code == NOT)
        op = XEXP (op, 0), code = GET_CODE (op);

      switch (code)
        {
        case CONST_INT:
          if ((unsigned HOST_WIDE_INT)INTVAL (op) > 63
              && mode != QImode)
            *total += COSTS_N_INSNS (1);        /* 2 on VAX 2 */
          break;
        case CONST:
        case LABEL_REF:
        case SYMBOL_REF:
          *total += COSTS_N_INSNS (1);          /* 2 on VAX 2 */
          break;
        case CONST_DOUBLE:
          if (GET_MODE_CLASS (GET_MODE (op)) == MODE_FLOAT)
            {
              /* Registers are faster than floating point constants -- even
                 those constants which can be encoded in a single byte.  */
              if (vax_float_literal (op))
                *total += COSTS_N_INSNS (1);
              else
                *total += (GET_MODE (x) == DFmode
                           ? COSTS_N_INSNS (3) : COSTS_N_INSNS (2));
            }
          else
            {
              if (CONST_DOUBLE_HIGH (op) != 0
                  || (unsigned HOST_WIDE_INT)CONST_DOUBLE_LOW (op) > 63)
                *total += COSTS_N_INSNS (2);
            }
          break;
        case MEM:
          *total += COSTS_N_INSNS (1);          /* 2 on VAX 2 */
          if (!REG_P (XEXP (op, 0)))
            *total += COSTS_N_INSNS (vax_address_cost_1 (XEXP (op, 0)));
          break;
        case REG:
        case SUBREG:
          break;
        default:
          *total += COSTS_N_INSNS (1);
          break;
        }
    }
  return true;
}
\f
/* With ELF we do not support GOT entries for external `symbol+offset'
   references, so do not accept external symbol references if an offset
   is to be added.  Do not accept external symbol references at all if
   LOCAL_P is set.  This is for cases where making a reference indirect
   would make it invalid.  Do not accept any kind of symbols if SYMBOL_P
   is clear.  This is for situations where the a reference is used as an
   immediate value for operations other than address loads (MOVA/PUSHA),
   as those operations do not support PC-relative immediates.  */

bool
vax_acceptable_pic_operand_p (rtx x ATTRIBUTE_UNUSED,
                              bool local_p ATTRIBUTE_UNUSED,
                              bool symbol_p ATTRIBUTE_UNUSED)
{
#ifdef NO_EXTERNAL_INDIRECT_ADDRESS
  if (GET_CODE (x) == CONST && GET_CODE (XEXP (x, 0)) == PLUS)
    {
      x = XEXP (XEXP (x, 0), 0);
      local_p = true;
    }
  switch (GET_CODE (x))
    {
    case SYMBOL_REF:
      return symbol_p && !(local_p && !SYMBOL_REF_LOCAL_P (x));
    case LABEL_REF:
      return symbol_p && !(local_p && LABEL_REF_NONLOCAL_P (x));
    default:
      break;
    }
#endif
  return true;
}
\f
/* Given a comparison code (NE, EQ, etc.) and the operands of a COMPARE,
   return the mode to be used for the comparison.  As we have the same
   interpretation of condition codes across all the instructions we just
   return the narrowest mode suitable for the comparison code requested.  */

extern machine_mode
vax_select_cc_mode (enum rtx_code op,
                    rtx x ATTRIBUTE_UNUSED, rtx y ATTRIBUTE_UNUSED)
{
  switch (op)
    {
    default:
      gcc_unreachable ();
    case NE:
    case EQ:
      return CCZmode;
    case GE:
    case LT:
      return CCNmode;
    case GT:
    case LE:
      return CCNZmode;
    case GEU:
    case GTU:
    case LEU:
    case LTU:
      return CCmode;
    }
}

/* Return the narrowest CC mode that spans both modes offered.  If they
   intersect, this will be the wider of the two, and if they do not then
   find one that is a superset of both (i.e. CCNZmode for a pair
   consisting of CCNmode and CCZmode).  A wider CC writer will satisfy
   a narrower CC reader, e.g. a comparison operator that uses CCZmode
   can use a CCNZmode output of a previous instruction.  */

static machine_mode
vax_cc_modes_compatible (machine_mode m1, machine_mode m2)
{
  switch (m1)
    {
    default:
      gcc_unreachable ();
    case E_CCmode:
      switch (m2)
        {
        default:
          gcc_unreachable ();
        case E_CCmode:
        case E_CCNZmode:
        case E_CCNmode:
        case E_CCZmode:
          return m1;
        }
    case E_CCNZmode:
      switch (m2)
        {
        default:
          gcc_unreachable ();
        case E_CCmode:
          return m2;
        case E_CCNmode:
        case E_CCNZmode:
        case E_CCZmode:
          return m1;
        }
    case E_CCNmode:
    case E_CCZmode:
      switch (m2)
        {
        default:
          gcc_unreachable ();
        case E_CCmode:
        case E_CCNZmode:
          return m2;
        case E_CCNmode:
        case E_CCZmode:
          return m1 == m2 ? m1 : E_CCNZmode;
        }
    }
}
\f
/* Mark PSL as clobbered for compatibility with the CC0 representation.  */

static rtx_insn *
vax_md_asm_adjust (vec<rtx> &outputs ATTRIBUTE_UNUSED,
                   vec<rtx> &inputs ATTRIBUTE_UNUSED,
                   vec<machine_mode> &input_modes ATTRIBUTE_UNUSED,
                   vec<const char *> &constraints ATTRIBUTE_UNUSED,
                   vec<rtx> &clobbers, HARD_REG_SET &clobbered_regs,
                   location_t /*loc*/)
{
  clobbers.safe_push (gen_rtx_REG (CCmode, VAX_PSL_REGNUM));
  SET_HARD_REG_BIT (clobbered_regs, VAX_PSL_REGNUM);
  return NULL;
}
\f
/* Output code to add DELTA to the first argument, and then jump to FUNCTION.
   Used for C++ multiple inheritance.
        .mask   ^m<r2,r3,r4,r5,r6,r7,r8,r9,r10,r11>  #conservative entry mask
        addl2   $DELTA, 4(ap)   #adjust first argument
        jmp     FUNCTION+2      #jump beyond FUNCTION's entry mask
*/

static void
vax_output_mi_thunk (FILE * file,
                     tree thunk ATTRIBUTE_UNUSED,
                     HOST_WIDE_INT delta,
                     HOST_WIDE_INT vcall_offset ATTRIBUTE_UNUSED,
                     tree function)
{
  const char *fnname = IDENTIFIER_POINTER (DECL_ASSEMBLER_NAME (thunk));

  assemble_start_function (thunk, fnname);
  fprintf (file, "\t.word 0x0ffc\n\taddl2 $" HOST_WIDE_INT_PRINT_DEC, delta);
  asm_fprintf (file, ",4(%Rap)\n");
  fprintf (file, "\tjmp ");
  assemble_name (file,  XSTR (XEXP (DECL_RTL (function), 0), 0));
  fprintf (file, "+2\n");
  assemble_end_function (thunk, fnname);
}
\f
static rtx
vax_struct_value_rtx (tree fntype ATTRIBUTE_UNUSED,
                      int incoming ATTRIBUTE_UNUSED)
{
  return gen_rtx_REG (Pmode, VAX_STRUCT_VALUE_REGNUM);
}

/* Return true if we use LRA instead of reload pass.  */

static bool
vax_lra_p (void)
{
  return TARGET_LRA;
}

/* Output integer move instructions.  */

bool
vax_maybe_split_dimode_move (rtx *operands)
{
  return (TARGET_QMATH
          && (!MEM_P (operands[0])
              || GET_CODE (XEXP (operands[0], 0)) == PRE_DEC
              || GET_CODE (XEXP (operands[0], 0)) == POST_INC
              || !illegal_addsub_di_memory_operand (operands[0], DImode))
          && ((CONST_INT_P (operands[1])
               && (unsigned HOST_WIDE_INT) INTVAL (operands[1]) >= 64)
              || GET_CODE (operands[1]) == CONST_DOUBLE));
}

const char *
vax_output_int_move (rtx insn ATTRIBUTE_UNUSED, rtx *operands,
                     machine_mode mode)
{
  rtx hi[3], lo[3];
  const char *pattern_hi, *pattern_lo;
  bool push_p;

  switch (mode)
    {
    case E_DImode:
      if (operands[1] == const0_rtx)
        return "clrq %0";
      if (TARGET_QMATH && optimize_size
          && (CONST_INT_P (operands[1])
              || GET_CODE (operands[1]) == CONST_DOUBLE))
        {
          unsigned HOST_WIDE_INT hval, lval;
          int n;

          if (GET_CODE (operands[1]) == CONST_DOUBLE)
            {
              gcc_assert (HOST_BITS_PER_WIDE_INT != 64);

              /* Make sure only the low 32 bits are valid.  */
              lval = CONST_DOUBLE_LOW (operands[1]) & 0xffffffff;
              hval = CONST_DOUBLE_HIGH (operands[1]) & 0xffffffff;
            }
          else
            {
              lval = INTVAL (operands[1]);
              hval = 0;
            }

          /* Here we see if we are trying to see if the 64bit value is really
             a 6bit shifted some arbitrary amount.  If so, we can use ashq to
             shift it to the correct value saving 7 bytes (1 addr-mode-byte +
             8 bytes - 1 shift byte - 1 short literal byte.  */
          if (lval != 0
              && (n = exact_log2 (lval & (- lval))) != -1
              && (lval >> n) < 64)
            {
              lval >>= n;

              /* On 32bit platforms, if the 6bits didn't overflow into the
                 upper 32bit value that value better be 0.  If we have
                 overflowed, make sure it wasn't too much.  */
              if (HOST_BITS_PER_WIDE_INT == 32 && hval != 0)
                {
                  if (n <= 26 || hval >= ((unsigned)1 << (n - 26)))
                    n = 0;      /* failure */
                  else
                    lval |= hval << (32 - n);
                }
              /*  If n is 0, then ashq is not the best way to emit this.  */
              if (n > 0)
                {
                  operands[1] = GEN_INT (lval);
                  operands[2] = GEN_INT (n);
                  return "ashq %2,%D1,%0";
                }
#if HOST_BITS_PER_WIDE_INT == 32
            }
          /* On 32bit platforms, if the low 32bit value is 0, checkout the
             upper 32bit value.  */
          else if (hval != 0
                   && (n = exact_log2 (hval & (- hval)) - 1) != -1
                   && (hval >> n) < 64)
            {
              operands[1] = GEN_INT (hval >> n);
              operands[2] = GEN_INT (n + 32);
              return "ashq %2,%D1,%0";
#endif
            }
        }

      if (vax_maybe_split_dimode_move (operands))
        {
          hi[0] = operands[0];
          hi[1] = operands[1];

          split_quadword_operands (insn, SET, hi, lo, 2);

          pattern_lo = vax_output_int_move (NULL, lo, SImode);
          pattern_hi = vax_output_int_move (NULL, hi, SImode);

          /* The patterns are just movl/movl or pushl/pushl then a movq will
             be shorter (1 opcode byte + 1 addrmode byte + 8 immediate value
             bytes .vs. 2 opcode bytes + 2 addrmode bytes + 8 immediate value
             value bytes.  */
          if ((startswith (pattern_lo, "movl")
              && startswith (pattern_hi, "movl"))
              || (startswith (pattern_lo, "pushl")
                  && startswith (pattern_hi, "pushl")))
            return "movq %1,%0";

          if (MEM_P (operands[0])
              && GET_CODE (XEXP (operands[0], 0)) == PRE_DEC)
            {
              output_asm_insn (pattern_hi, hi);
              operands[0] = lo[0];
              operands[1] = lo[1];
              operands[2] = lo[2];
              return pattern_lo;
            }
          else
            {
              output_asm_insn (pattern_lo, lo);
              operands[0] = hi[0];
              operands[1] = hi[1];
              operands[2] = hi[2];
              return pattern_hi;
            }
        }
      return "movq %1,%0";

    case E_SImode:
      push_p = push_operand (operands[0], SImode);

      if (symbolic_operand (operands[1], SImode))
        return push_p ? "pushab %a1" : "movab %a1,%0";

      if (operands[1] == const0_rtx)
        return push_p ? "pushl %1" : "clrl %0";

      if (CONST_INT_P (operands[1])
          && (unsigned HOST_WIDE_INT) INTVAL (operands[1]) >= 64)
        {
          HOST_WIDE_INT i = INTVAL (operands[1]);
          int n;
          if ((unsigned HOST_WIDE_INT)(~i) < 64)
            return "mcoml %N1,%0";
          if ((unsigned HOST_WIDE_INT)i < 0x100)
            return "movzbl %1,%0";
          if (i >= -0x80 && i < 0)
            return "cvtbl %1,%0";
          if (optimize_size
              && (n = exact_log2 (i & (-i))) != -1
              && ((unsigned HOST_WIDE_INT)i >> n) < 64)
            {
              operands[1] = GEN_INT ((unsigned HOST_WIDE_INT)i >> n);
              operands[2] = GEN_INT (n);
              return "ashl %2,%1,%0";
            }
          if ((unsigned HOST_WIDE_INT)i < 0x10000)
            return "movzwl %1,%0";
          if (i >= -0x8000 && i < 0)
            return "cvtwl %1,%0";
        }
      return push_p ? "pushl %1" : "movl %1,%0";

    case E_HImode:
      if (CONST_INT_P (operands[1]))
        {
          HOST_WIDE_INT i = INTVAL (operands[1]);
          if (i == 0)
            return "clrw %0";
          else if ((unsigned HOST_WIDE_INT)i < 64)
            return "movw %1,%0";
          else if ((unsigned HOST_WIDE_INT)~i < 64)
            return "mcomw %H1,%0";
          else if ((unsigned HOST_WIDE_INT)i < 256)
            return "movzbw %1,%0";
          else if (i >= -0x80 && i < 0)
            return "cvtbw %1,%0";
        }
      return "movw %1,%0";

    case E_QImode:
      if (CONST_INT_P (operands[1]))
        {
          HOST_WIDE_INT i = INTVAL (operands[1]);
          if (i == 0)
            return "clrb %0";
          else if ((unsigned HOST_WIDE_INT)~i < 64)
            return "mcomb %B1,%0";
        }
      return "movb %1,%0";

    default:
      gcc_unreachable ();
    }
}

/* Output integer add instructions.

   The space-time-opcode tradeoffs for addition vary by model of VAX.

   On a VAX 3 "movab (r1)[r2],r3" is faster than "addl3 r1,r2,r3",
   but it not faster on other models.

   "movab #(r1),r2" is usually shorter than "addl3 #,r1,r2", and is
   faster on a VAX 3, but some VAXen (e.g. VAX 9000) will stall if
   a register is used in an address too soon after it is set.
   Compromise by using movab only when it is shorter than the add
   or the base register in the address is one of sp, ap, and fp,
   which are not modified very often.  */

const char *
vax_output_int_add (rtx_insn *insn, rtx *operands, machine_mode mode)
{
  switch (mode)
    {
    case E_DImode:
      {
        rtx low[3];
        const char *pattern;
        int carry = 1;
        bool sub;

        if (TARGET_QMATH && 0)
          debug_rtx (insn);

        split_quadword_operands (insn, PLUS, operands, low, 3);

        if (TARGET_QMATH)
          {
            gcc_assert (rtx_equal_p (operands[0], operands[1]));
#ifdef NO_EXTERNAL_INDIRECT_ADDRESS
            gcc_assert (!flag_pic
                        || !non_pic_external_memory_operand (low[2], SImode));
            gcc_assert (!flag_pic
                        || !non_pic_external_memory_operand (low[0], SImode));
#endif

            /* No reason to add a 0 to the low part and thus no carry, so just
               emit the appropriate add/sub instruction.  */
            if (low[2] == const0_rtx)
              return vax_output_int_add (NULL, operands, SImode);

            /* Are we doing addition or subtraction?  */
            sub = CONST_INT_P (operands[2]) && INTVAL (operands[2]) < 0;

            /* We can't use vax_output_int_add since some the patterns don't
               modify the carry bit.  */
            if (sub)
              {
                if (low[2] == constm1_rtx)
                  pattern = "decl %0";
                else
                  pattern = "subl2 $%n2,%0";
              }
            else
              {
                if (low[2] == const1_rtx)
                  pattern = "incl %0";
                else
                  pattern = "addl2 %2,%0";
              }
            output_asm_insn (pattern, low);

            /* In 2's complement, -n = ~n + 1.  Since we are dealing with
               two 32bit parts, we complement each and then add one to
               low part.  We know that the low part can't overflow since
               it's value can never be 0.  */
            if (sub)
                return "sbwc %N2,%0";
            return "adwc %2,%0";
          }

        /* Add low parts.  */
        if (rtx_equal_p (operands[0], operands[1]))
          {
            if (low[2] == const0_rtx)
        /* Should examine operand, punt if not POST_INC.  */
              pattern = "tstl %0", carry = 0;
            else if (low[2] == const1_rtx)
              pattern = "incl %0";
            else
              pattern = "addl2 %2,%0";
          }
        else
          {
            if (low[2] == const0_rtx)
              pattern = "movl %1,%0", carry = 0;
            else
              pattern = "addl3 %2,%1,%0";
          }
        if (pattern)
          output_asm_insn (pattern, low);
        if (!carry)
          /* If CARRY is 0, we don't have any carry value to worry about.  */
          return get_insn_template (CODE_FOR_addsi3, insn);
        /* %0 = C + %1 + %2 */
        if (!rtx_equal_p (operands[0], operands[1]))
          output_asm_insn ((operands[1] == const0_rtx
                            ? "clrl %0"
                            : "movl %1,%0"), operands);
        return "adwc %2,%0";
      }

    case E_SImode:
      if (rtx_equal_p (operands[0], operands[1]))
        {
          if (operands[2] == const1_rtx)
            return "incl %0";
          if (operands[2] == constm1_rtx)
            return "decl %0";
          if (CONST_INT_P (operands[2])
              && (unsigned HOST_WIDE_INT) (- INTVAL (operands[2])) < 64)
            return "subl2 $%n2,%0";
          if (CONST_INT_P (operands[2])
              && (unsigned HOST_WIDE_INT) INTVAL (operands[2]) >= 64
              && REG_P (operands[1])
              && ((INTVAL (operands[2]) < 32767 && INTVAL (operands[2]) > -32768)
                   || REGNO (operands[1]) > 11))
            return "movab %c2(%1),%0";
          if (REG_P (operands[0]) && symbolic_operand (operands[2], SImode))
            return "movab %a2[%0],%0";
          return "addl2 %2,%0";
        }

      if (rtx_equal_p (operands[0], operands[2]))
        {
          if (REG_P (operands[0]) && symbolic_operand (operands[1], SImode))
            return "movab %a1[%0],%0";
          return "addl2 %1,%0";
        }

      if (CONST_INT_P (operands[2])
          && INTVAL (operands[2]) < 32767
          && INTVAL (operands[2]) > -32768
          && REG_P (operands[1])
          && push_operand (operands[0], SImode))
        return "pushab %c2(%1)";

      if (CONST_INT_P (operands[2])
          && (unsigned HOST_WIDE_INT) (- INTVAL (operands[2])) < 64)
        return "subl3 $%n2,%1,%0";

      if (CONST_INT_P (operands[2])
          && (unsigned HOST_WIDE_INT) INTVAL (operands[2]) >= 64
          && REG_P (operands[1])
          && ((INTVAL (operands[2]) < 32767 && INTVAL (operands[2]) > -32768)
               || REGNO (operands[1]) > 11))
        return "movab %c2(%1),%0";

      /* Add this if using gcc on a VAX 3xxx:
      if (REG_P (operands[1]) && REG_P (operands[2]))
        return "movab (%1)[%2],%0";
      */

      if (REG_P (operands[1]) && symbolic_operand (operands[2], SImode))
        {
          if (push_operand (operands[0], SImode))
            return "pushab %a2[%1]";
          return "movab %a2[%1],%0";
        }

      if (REG_P (operands[2]) && symbolic_operand (operands[1], SImode))
        {
          if (push_operand (operands[0], SImode))
            return "pushab %a1[%2]";
          return "movab %a1[%2],%0";
        }

      if (flag_pic && REG_P (operands[0])
          && symbolic_operand (operands[2], SImode))
        return "movab %a2,%0;addl2 %1,%0";

      if (flag_pic
          && (symbolic_operand (operands[1], SImode)
              || symbolic_operand (operands[2], SImode)))
        debug_rtx (insn);

      return "addl3 %1,%2,%0";

    case E_HImode:
      if (rtx_equal_p (operands[0], operands[1]))
        {
          if (operands[2] == const1_rtx)
            return "incw %0";
          if (operands[2] == constm1_rtx)
            return "decw %0";
          if (CONST_INT_P (operands[2])
              && (unsigned HOST_WIDE_INT) (- INTVAL (operands[2])) < 64)
            return "subw2 $%n2,%0";
          return "addw2 %2,%0";
        }
      if (rtx_equal_p (operands[0], operands[2]))
        return "addw2 %1,%0";
      if (CONST_INT_P (operands[2])
          && (unsigned HOST_WIDE_INT) (- INTVAL (operands[2])) < 64)
        return "subw3 $%n2,%1,%0";
      return "addw3 %1,%2,%0";

    case E_QImode:
      if (rtx_equal_p (operands[0], operands[1]))
        {
          if (operands[2] == const1_rtx)
            return "incb %0";
          if (operands[2] == constm1_rtx)
            return "decb %0";
          if (CONST_INT_P (operands[2])
              && (unsigned HOST_WIDE_INT) (- INTVAL (operands[2])) < 64)
            return "subb2 $%n2,%0";
          return "addb2 %2,%0";
        }
      if (rtx_equal_p (operands[0], operands[2]))
        return "addb2 %1,%0";
      if (CONST_INT_P (operands[2])
          && (unsigned HOST_WIDE_INT) (- INTVAL (operands[2])) < 64)
        return "subb3 $%n2,%1,%0";
      return "addb3 %1,%2,%0";

    default:
      gcc_unreachable ();
    }
}

const char *
vax_output_int_subtract (rtx_insn *insn, rtx *operands, machine_mode mode)
{
  switch (mode)
    {
    case E_DImode:
      {
        rtx low[3];
        const char *pattern;
        int carry = 1;

        if (TARGET_QMATH && 0)
          debug_rtx (insn);

        split_quadword_operands (insn, MINUS, operands, low, 3);

        if (TARGET_QMATH)
          {
            if (operands[1] == const0_rtx && low[1] == const0_rtx)
              {
                /* Negation is tricky.  It's basically complement and increment.
                   Negate hi, then lo, and subtract the carry back.  */
                if ((MEM_P (low[0]) && GET_CODE (XEXP (low[0], 0)) == POST_INC)
                    || (MEM_P (operands[0])
                        && GET_CODE (XEXP (operands[0], 0)) == POST_INC))
                  fatal_insn ("illegal operand detected", insn);
                output_asm_insn ("mnegl %2,%0", operands);
                output_asm_insn ("mnegl %2,%0", low);
                return "sbwc $0,%0";
              }
            gcc_assert (rtx_equal_p (operands[0], operands[1]));
            gcc_assert (rtx_equal_p (low[0], low[1]));
            if (low[2] == const1_rtx)
              output_asm_insn ("decl %0", low);
            else
              output_asm_insn ("subl2 %2,%0", low);
            return "sbwc %2,%0";
          }

        /* Subtract low parts.  */
        if (rtx_equal_p (operands[0], operands[1]))
          {
            if (low[2] == const0_rtx)
              pattern = 0, carry = 0;
            else if (low[2] == constm1_rtx)
              pattern = "decl %0";
            else
              pattern = "subl2 %2,%0";
          }
        else
          {
            if (low[2] == constm1_rtx)
              pattern = "decl %0";
            else if (low[2] == const0_rtx)
              pattern = get_insn_template (CODE_FOR_movsi, insn), carry = 0;
            else
              pattern = "subl3 %2,%1,%0";
          }
        if (pattern)
          output_asm_insn (pattern, low);
        if (carry)
          {
            if (!rtx_equal_p (operands[0], operands[1]))
              return "movl %1,%0;sbwc %2,%0";
            return "sbwc %2,%0";
            /* %0 = %2 - %1 - C */
          }
        return get_insn_template (CODE_FOR_subsi3, insn);
      }

    default:
      gcc_unreachable ();
  }
}

/* True if X is an rtx for a constant that is a valid address.  */

bool
legitimate_constant_address_p (rtx x)
{
  if (GET_CODE (x) == LABEL_REF || GET_CODE (x) == SYMBOL_REF
          || CONST_INT_P (x) || GET_CODE (x) == HIGH)
    return true;
  if (GET_CODE (x) != CONST)
    return false;
#ifdef NO_EXTERNAL_INDIRECT_ADDRESS
  if (flag_pic
      && GET_CODE (XEXP (XEXP (x, 0), 0)) == SYMBOL_REF
      && !SYMBOL_REF_LOCAL_P (XEXP (XEXP (x, 0), 0)))
    return false;
#endif
   return true;
}

/* The other macros defined here are used only in legitimate_address_p ().  */

/* Nonzero if X is a hard reg that can be used as an index
   or, if not strict, if it is a pseudo reg.  */
#define INDEX_REGISTER_P(X, STRICT) \
(REG_P (X) && (!(STRICT) || REGNO_OK_FOR_INDEX_P (REGNO (X))))

/* Nonzero if X is a hard reg that can be used as a base reg
   or, if not strict, if it is a pseudo reg.  */
#define BASE_REGISTER_P(X, STRICT) \
(REG_P (X) && (!(STRICT) || REGNO_OK_FOR_BASE_P (REGNO (X))))

#ifdef NO_EXTERNAL_INDIRECT_ADDRESS

/* Re-definition of CONSTANT_ADDRESS_P, which is true only when there
   are no SYMBOL_REFs for external symbols present.  */

static bool
indirectable_constant_address_p (rtx x, bool indirect)
{
  if (GET_CODE (x) == SYMBOL_REF)
    return !flag_pic || SYMBOL_REF_LOCAL_P (x) || !indirect;

  if (GET_CODE (x) == CONST)
    return !flag_pic
           || GET_CODE (XEXP (XEXP (x, 0), 0)) != SYMBOL_REF
           || SYMBOL_REF_LOCAL_P (XEXP (XEXP (x, 0), 0));

  return CONSTANT_ADDRESS_P (x);
}

#else /* not NO_EXTERNAL_INDIRECT_ADDRESS */

static bool
indirectable_constant_address_p (rtx x, bool indirect ATTRIBUTE_UNUSED)
{
  return CONSTANT_ADDRESS_P (x);
}

#endif /* not NO_EXTERNAL_INDIRECT_ADDRESS */

/* True if X is an address which can be indirected.  External symbols
   could be in a sharable image library, so we disallow those.  */

static bool
indirectable_address_p (rtx x, bool strict, bool indirect)
{
  if (indirectable_constant_address_p (x, indirect)
      || BASE_REGISTER_P (x, strict))
    return true;
  if (GET_CODE (x) != PLUS
      || !BASE_REGISTER_P (XEXP (x, 0), strict)
      || (flag_pic && !CONST_INT_P (XEXP (x, 1))))
    return false;
  return indirectable_constant_address_p (XEXP (x, 1), indirect);
}

/* Return true if x is a valid address not using indexing.
   (This much is the easy part.)  */
static bool
nonindexed_address_p (rtx x, bool strict)
{
  rtx xfoo0;
  if (REG_P (x))
    {
      if (! reload_in_progress
          || reg_equiv_mem (REGNO (x)) == 0
          || indirectable_address_p (reg_equiv_mem (REGNO (x)), strict, false))
        return true;
    }
  if (indirectable_constant_address_p (x, false))
    return true;
  if (indirectable_address_p (x, strict, false))
    return true;
  xfoo0 = XEXP (x, 0);
  if (MEM_P (x) && indirectable_address_p (xfoo0, strict, true))
    return true;
  if ((GET_CODE (x) == PRE_DEC || GET_CODE (x) == POST_INC)
      && BASE_REGISTER_P (xfoo0, strict))
    return true;
  return false;
}

/* True if PROD is either a reg times size of mode MODE and MODE is less
   than or equal 8 bytes, or just a reg if MODE is one byte.  For a MULT
   RTX we accept its operands in either order, however ASHIFT is not
   commutative, so in that case reg has to be the left operand.  */

static bool
index_term_p (rtx prod, machine_mode mode, bool strict)
{
  rtx xfoo0, xfoo1;
  bool log_p;

  if (GET_MODE_SIZE (mode) == 1)
    return BASE_REGISTER_P (prod, strict);

  if ((GET_CODE (prod) != MULT && GET_CODE (prod) != ASHIFT)
      || GET_MODE_SIZE (mode) > 8)
    return false;

  log_p = GET_CODE (prod) == ASHIFT;
  xfoo0 = XEXP (prod, 0);
  xfoo1 = XEXP (prod, 1);

  if (!log_p
      && CONST_INT_P (xfoo0)
      && GET_MODE_SIZE (mode) == INTVAL (xfoo0)
      && INDEX_REGISTER_P (xfoo1, strict))
    return true;

  if (CONST_INT_P (xfoo1)
      && GET_MODE_SIZE (mode) == (log_p ? 1 << INTVAL (xfoo1) : INTVAL (xfoo1))
      && INDEX_REGISTER_P (xfoo0, strict))
    return true;

  return false;
}

/* Return true if X is the sum of a register
   and a valid index term for mode MODE.  */
static bool
reg_plus_index_p (rtx x, machine_mode mode, bool strict)
{
  rtx xfoo0, xfoo1;

  if (GET_CODE (x) != PLUS)
    return false;

  xfoo0 = XEXP (x, 0);
  xfoo1 = XEXP (x, 1);

  if (BASE_REGISTER_P (xfoo0, strict) && index_term_p (xfoo1, mode, strict))
    return true;

  if (BASE_REGISTER_P (xfoo1, strict) && index_term_p (xfoo0, mode, strict))
    return true;

  return false;
}

/* Return true if xfoo0 and xfoo1 constitute a valid indexed address.  */
static bool
indexable_address_p (rtx xfoo0, rtx xfoo1, machine_mode mode, bool strict)
{
  if (!CONSTANT_ADDRESS_P (xfoo0))
    return false;
  if (BASE_REGISTER_P (xfoo1, strict))
    return !flag_pic || mode == QImode;
  if (flag_pic && symbolic_operand (xfoo0, SImode))
    return false;
  return reg_plus_index_p (xfoo1, mode, strict);
}

/* legitimate_address_p returns true if it recognizes an RTL expression "x"
   that is a valid memory address for an instruction.
   The MODE argument is the machine mode for the MEM expression
   that wants to use this address.  */
bool
vax_legitimate_address_p (machine_mode mode, rtx x, bool strict, code_helper)
{
  rtx xfoo0, xfoo1;

  if (nonindexed_address_p (x, strict))
    return true;

  if (GET_CODE (x) != PLUS)
    return false;

  /* Handle <address>[index] represented with index-sum outermost */

  xfoo0 = XEXP (x, 0);
  xfoo1 = XEXP (x, 1);

  if (index_term_p (xfoo0, mode, strict)
      && nonindexed_address_p (xfoo1, strict))
    return true;

  if (index_term_p (xfoo1, mode, strict)
      && nonindexed_address_p (xfoo0, strict))
    return true;

  /* Handle offset(reg)[index] with offset added outermost */

  if (indexable_address_p (xfoo0, xfoo1, mode, strict)
      || indexable_address_p (xfoo1, xfoo0, mode, strict))
    return true;

  return false;
}

/* Return true if x (a legitimate address expression) has an effect that
   depends on the machine mode it is used for.  On the VAX, the predecrement
   and postincrement address depend thus (the amount of decrement or
   increment being the length of the operand) and all indexed address depend
   thus (because the index scale factor is the length of the operand).  */

static bool
vax_mode_dependent_address_p (const_rtx x, addr_space_t as ATTRIBUTE_UNUSED)
{
  rtx xfoo0, xfoo1;

  /* Auto-increment cases are now dealt with generically in recog.cc.  */
  if (GET_CODE (x) != PLUS)
    return false;

  xfoo0 = XEXP (x, 0);
  xfoo1 = XEXP (x, 1);

  if (CONST_INT_P (xfoo0) && REG_P (xfoo1))
    return false;
  if (CONST_INT_P (xfoo1) && REG_P (xfoo0))
    return false;
  if (!flag_pic && CONSTANT_ADDRESS_P (xfoo0) && REG_P (xfoo1))
    return false;
  if (!flag_pic && CONSTANT_ADDRESS_P (xfoo1) && REG_P (xfoo0))
    return false;

  return true;
}

static rtx
fixup_mathdi_operand (rtx x, machine_mode mode)
{
  if (illegal_addsub_di_memory_operand (x, mode))
    {
      rtx addr = XEXP (x, 0);
      rtx temp = gen_reg_rtx (Pmode);
      rtx offset = 0;
#ifdef NO_EXTERNAL_INDIRECT_ADDRESS
      if (GET_CODE (addr) == CONST && flag_pic)
        {
          offset = XEXP (XEXP (addr, 0), 1);
          addr = XEXP (XEXP (addr, 0), 0);
        }
#endif
      emit_move_insn (temp, addr);
      if (offset)
        temp = gen_rtx_PLUS (Pmode, temp, offset);
      x = gen_rtx_MEM (DImode, temp);
    }
  return x;
}

void
vax_expand_addsub_di_operands (rtx * operands, enum rtx_code code)
{
  int hi_only = operand_subword (operands[2], 0, 0, DImode) == const0_rtx;
  rtx temp;

  rtx (*gen_old_insn)(rtx, rtx, rtx);
  rtx (*gen_si_insn)(rtx, rtx, rtx);
  rtx (*gen_insn)(rtx, rtx, rtx);

  if (code == PLUS)
    {
      gen_old_insn = gen_adddi3_old;
      gen_si_insn = gen_addsi3;
      gen_insn = gen_adcdi3;
    }
  else if (code == MINUS)
    {
      gen_old_insn = gen_subdi3_old;
      gen_si_insn = gen_subsi3;
      gen_insn = gen_sbcdi3;
    }
  else
    gcc_unreachable ();

  /* If this is addition (thus operands are commutative) and if there is one
     addend that duplicates the desination, we want that addend to be the
     first addend.  */
  if (code == PLUS
      && rtx_equal_p (operands[0], operands[2])
      && !rtx_equal_p (operands[1], operands[2]))
    {
      temp = operands[2];
      operands[2] = operands[1];
      operands[1] = temp;
    }

  if (!TARGET_QMATH)
    {
      emit_insn ((*gen_old_insn) (operands[0], operands[1], operands[2]));
    }
  else if (hi_only)
    {
      if (!rtx_equal_p (operands[0], operands[1])
          && (REG_P (operands[0]) && MEM_P (operands[1])))
        {
          emit_move_insn (operands[0], operands[1]);
          operands[1] = operands[0];
        }

      operands[0] = fixup_mathdi_operand (operands[0], DImode);
      operands[1] = fixup_mathdi_operand (operands[1], DImode);
      operands[2] = fixup_mathdi_operand (operands[2], DImode);

      if (!rtx_equal_p (operands[0], operands[1]))
        emit_move_insn (operand_subword (operands[0], 0, 0, DImode),
                          operand_subword (operands[1], 0, 0, DImode));

      emit_insn ((*gen_si_insn) (operand_subword (operands[0], 1, 0, DImode),
                                 operand_subword (operands[1], 1, 0, DImode),
                                 operand_subword (operands[2], 1, 0, DImode)));
    }
  else
    {
      /* If we are adding a value to itself, that's really a multiply by 2,
         and that's just a left shift by 1.  If subtracting, it's just 0.  */
      if (rtx_equal_p (operands[1], operands[2]))
        {
          if (code == PLUS)
            emit_insn (gen_ashldi3 (operands[0], operands[1], const1_rtx));
          else
            emit_move_insn (operands[0], const0_rtx);
          return;
        }

      operands[0] = fixup_mathdi_operand (operands[0], DImode);

      /* If an operand is the same as operand[0], use the operand[0] rtx
         because fixup will an equivalent rtx but not an equal one. */

      if (rtx_equal_p (operands[0], operands[1]))
        operands[1] = operands[0];
      else
        operands[1] = fixup_mathdi_operand (operands[1], DImode);

      if (rtx_equal_p (operands[0], operands[2]))
        operands[2] = operands[0];
      else
        operands[2] = fixup_mathdi_operand (operands[2], DImode);

      /* If we are adding or subtracting 0, then this is a move.  */
      if (code == PLUS && operands[1] == const0_rtx)
        {
          temp = operands[2];
          operands[2] = operands[1];
          operands[1] = temp;
        }
      if (operands[2] == const0_rtx)
        {
          emit_move_insn (operands[0], operands[1]);
          return;
        }

      /* If we are subtracting not from ourselves [d = a - b], and because the
         carry ops are two operand only, we would need to do a move prior to
         the subtract.  And if d == b, we would need a temp otherwise
         [d = a, d -= d] and we end up with 0.  Instead we rewrite d = a - b
         into d = -b, d += a.  Since -b can never overflow, even if b == d,
         no temp is needed.

         If we are doing addition, since the carry ops are two operand, if
         we aren't adding to ourselves, move the first addend to the
         destination first.  */

      gcc_assert (operands[1] != const0_rtx || code == MINUS);
      if (!rtx_equal_p (operands[0], operands[1]) && operands[1] != const0_rtx)
        {
          if (code == MINUS && CONSTANT_P (operands[1]))
            {
              emit_insn (gen_sbcdi3 (operands[0], const0_rtx, operands[2]));
              code = PLUS;
              gen_insn = gen_adcdi3;
              operands[2] = operands[1];
              operands[1] = operands[0];
            }
          else
            emit_move_insn (operands[0], operands[1]);
        }

      /* Subtracting a constant will have been rewritten to an addition of the
         negative of that constant before we get here.  */
      gcc_assert (!CONSTANT_P (operands[2]) || code == PLUS);
      emit_insn ((*gen_insn) (operands[0], operands[1], operands[2]));
    }
}

/* Output assembler code for a block containing the constant parts
   of a trampoline, leaving space for the variable parts.  */

/* On the VAX, the trampoline contains an entry mask and two instructions:
     .word NN
     movl $STATIC,r0   (store the functions static chain)
     jmp  *$FUNCTION   (jump to function code at address FUNCTION)  */

static void
vax_asm_trampoline_template (FILE *f ATTRIBUTE_UNUSED)
{
  assemble_aligned_integer (2, const0_rtx);
  assemble_aligned_integer (2, GEN_INT (0x8fd0));
  assemble_aligned_integer (4, const0_rtx);
  assemble_aligned_integer (1, GEN_INT (0x50 + STATIC_CHAIN_REGNUM));
  assemble_aligned_integer (2, GEN_INT (0x9f17));
  assemble_aligned_integer (4, const0_rtx);
}

/* We copy the register-mask from the function's pure code
   to the start of the trampoline.  */

static void
vax_trampoline_init (rtx m_tramp, tree fndecl, rtx cxt)
{
  rtx fnaddr = XEXP (DECL_RTL (fndecl), 0);
  rtx mem;

  emit_block_move (m_tramp, assemble_trampoline_template (),
                   GEN_INT (TRAMPOLINE_SIZE), BLOCK_OP_NORMAL);

  mem = adjust_address (m_tramp, HImode, 0);
  emit_move_insn (mem, gen_const_mem (HImode, fnaddr));

  mem = adjust_address (m_tramp, SImode, 4);
  emit_move_insn (mem, cxt);
  mem = adjust_address (m_tramp, SImode, 11);
  emit_move_insn (mem, plus_constant (Pmode, fnaddr, 2));
  emit_insn (gen_sync_istream ());
}

/* Value is the number of bytes of arguments automatically
   popped when returning from a subroutine call.
   FUNDECL is the declaration node of the function (as a tree),
   FUNTYPE is the data type of the function (as a tree),
   or for a library call it is an identifier node for the subroutine name.
   SIZE is the number of bytes of arguments passed on the stack.

   On the VAX, the RET insn pops a maximum of 255 args for any function.  */

static poly_int64
vax_return_pops_args (tree fundecl ATTRIBUTE_UNUSED,
                      tree funtype ATTRIBUTE_UNUSED, poly_int64 size)
{
  return size > 255 * 4 ? 0 : (HOST_WIDE_INT) size;
}

/* Implement TARGET_FUNCTION_ARG.  On the VAX all args are pushed.  */

static rtx
vax_function_arg (cumulative_args_t, const function_arg_info &)
{
  return NULL_RTX;
}

/* Update the data in CUM to advance over argument ARG.  */

static void
vax_function_arg_advance (cumulative_args_t cum_v,
                          const function_arg_info &arg)
{
  CUMULATIVE_ARGS *cum = get_cumulative_args (cum_v);

  *cum += (arg.promoted_size_in_bytes () + 3) & ~3;
}

static HOST_WIDE_INT
vax_starting_frame_offset (void)
{
  /* On ELF targets, reserve the top of the stack for exception handler
     stackadj value.  */
  return TARGET_ELF ? -4 : 0;
}