Workbench Add-On/Workbench Add-On - Volume 1.iso/BBS-Archive/Dev/gcc263-src.lha/gcc-2.6.3/calls.c

C/C++ Source or Header | 1994-11-14 | 100KB | 3,091 lines

/* Convert function calls to rtl insns, for GNU C compiler.
   Copyright (C) 1989, 1992, 1993, 1994 Free Software Foundation, Inc.

This file is part of GNU CC.

GNU CC is free software; you can redistribute it and/or modify
it under the terms of the GNU General Public License as published by
the Free Software Foundation; either version 2, or (at your option)
any later version.

GNU CC 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 GNU CC; see the file COPYING.  If not, write to
the Free Software Foundation, 675 Mass Ave, Cambridge, MA 02139, USA.  */

#include "config.h"
#include "rtl.h"
#include "tree.h"
#include "flags.h"
#include "expr.h"
#ifdef __STDC__
#include <stdarg.h>
#else
#include <varargs.h>
#endif
#include "insn-flags.h"

/* Decide whether a function's arguments should be processed
   from first to last or from last to first.

   They should if the stack and args grow in opposite directions, but
   only if we have push insns.  */

#ifdef PUSH_ROUNDING

#if defined (STACK_GROWS_DOWNWARD) != defined (ARGS_GROW_DOWNWARD)
#define PUSH_ARGS_REVERSED    /* If it's last to first */
#endif

#endif

/* Like STACK_BOUNDARY but in units of bytes, not bits.  */
#define STACK_BYTES (STACK_BOUNDARY / BITS_PER_UNIT)

/* Data structure and subroutines used within expand_call.  */

struct arg_data
{
  /* Tree node for this argument.  */
  tree tree_value;
  /* Mode for value; TYPE_MODE unless promoted.  */
  enum machine_mode mode;
  /* Current RTL value for argument, or 0 if it isn't precomputed.  */
  rtx value;
  /* Initially-compute RTL value for argument; only for const functions.  */
  rtx initial_value;
  /* Register to pass this argument in, 0 if passed on stack, or an
     EXPR_LIST if the arg is to be copied into multiple different
     registers.  */
  rtx reg;
  /* If REG was promoted from the actual mode of the argument expression,
     indicates whether the promotion is sign- or zero-extended.  */
  int unsignedp;
  /* Number of registers to use.  0 means put the whole arg in registers.
     Also 0 if not passed in registers.  */
  int partial;
  /* Non-zero if argument must be passed on stack.
     Note that some arguments may be passed on the stack
     even though pass_on_stack is zero, just because FUNCTION_ARG says so.
     pass_on_stack identifies arguments that *cannot* go in registers.  */
  int pass_on_stack;
  /* Offset of this argument from beginning of stack-args.  */
  struct args_size offset;
  /* Similar, but offset to the start of the stack slot.  Different from
     OFFSET if this arg pads downward.  */
  struct args_size slot_offset;
  /* Size of this argument on the stack, rounded up for any padding it gets,
     parts of the argument passed in registers do not count.
     If REG_PARM_STACK_SPACE is defined, then register parms
     are counted here as well.  */
  struct args_size size;
  /* Location on the stack at which parameter should be stored.  The store
     has already been done if STACK == VALUE.  */
  rtx stack;
  /* Location on the stack of the start of this argument slot.  This can
     differ from STACK if this arg pads downward.  This location is known
     to be aligned to FUNCTION_ARG_BOUNDARY.  */
  rtx stack_slot;
#ifdef ACCUMULATE_OUTGOING_ARGS
  /* Place that this stack area has been saved, if needed.  */
  rtx save_area;
#endif
#ifdef STRICT_ALIGNMENT
  /* If an argument's alignment does not permit direct copying into registers,
     copy in smaller-sized pieces into pseudos.  These are stored in a
     block pointed to by this field.  The next field says how many
     word-sized pseudos we made.  */
  rtx *aligned_regs;
  int n_aligned_regs;
#endif
};

#ifdef ACCUMULATE_OUTGOING_ARGS
/* A vector of one char per byte of stack space.  A byte if non-zero if
   the corresponding stack location has been used.
   This vector is used to prevent a function call within an argument from
   clobbering any stack already set up.  */
static char *stack_usage_map;

/* Size of STACK_USAGE_MAP.  */
static int highest_outgoing_arg_in_use;

/* stack_arg_under_construction is nonzero when an argument may be
   initialized with a constructor call (including a C function that
   returns a BLKmode struct) and expand_call must take special action
   to make sure the object being constructed does not overlap the
   argument list for the constructor call.  */
int stack_arg_under_construction;
#endif

static int calls_function    PROTO((tree, int));
static int calls_function_1    PROTO((tree, int));
static void emit_call_1        PROTO((rtx, tree, int, int, rtx, rtx, int,
                       rtx, int));
static void store_one_arg    PROTO ((struct arg_data *, rtx, int, int,
                    tree, int));

/* If WHICH is 1, return 1 if EXP contains a call to the built-in function
   `alloca'.

   If WHICH is 0, return 1 if EXP contains a call to any function.
   Actually, we only need return 1 if evaluating EXP would require pushing
   arguments on the stack, but that is too difficult to compute, so we just
   assume any function call might require the stack.  */

static tree calls_function_save_exprs;

static int
calls_function (exp, which)
     tree exp;
     int which;
{
  int val;
  calls_function_save_exprs = 0;
  val = calls_function_1 (exp, which);
  calls_function_save_exprs = 0;
  return val;
}

static int
calls_function_1 (exp, which)
     tree exp;
     int which;
{
  register int i;
  enum tree_code code = TREE_CODE (exp);
  int type = TREE_CODE_CLASS (code);
  int length = tree_code_length[(int) code];

  /* If this code is langauge-specific, we don't know what it will do.  */
  if ((int) code >= NUM_TREE_CODES)
    return 1;

  /* Only expressions and references can contain calls.  */
  if (type != 'e' && type != '<' && type != '1' && type != '2' && type != 'r'
      && type != 'b')
    return 0;

  switch (code)
    {
    case CALL_EXPR:
      if (which == 0)
    return 1;
      else if (TREE_CODE (TREE_OPERAND (exp, 0)) == ADDR_EXPR
           && (TREE_CODE (TREE_OPERAND (TREE_OPERAND (exp, 0), 0))
           == FUNCTION_DECL))
    {
      tree fndecl = TREE_OPERAND (TREE_OPERAND (exp, 0), 0);

      if ((DECL_BUILT_IN (fndecl)
           && DECL_FUNCTION_CODE (fndecl) == BUILT_IN_ALLOCA)
          || (DECL_SAVED_INSNS (fndecl)
          && (FUNCTION_FLAGS (DECL_SAVED_INSNS (fndecl))
              & FUNCTION_FLAGS_CALLS_ALLOCA)))
        return 1;
    }

      /* Third operand is RTL.  */
      length = 2;
      break;

    case SAVE_EXPR:
      if (SAVE_EXPR_RTL (exp) != 0)
    return 0;
      if (value_member (exp, calls_function_save_exprs))
    return 0;
      calls_function_save_exprs = tree_cons (NULL_TREE, exp,
                         calls_function_save_exprs);
      return (TREE_OPERAND (exp, 0) != 0
          && calls_function_1 (TREE_OPERAND (exp, 0), which));

    case BLOCK:
      {
    register tree local;

    for (local = BLOCK_VARS (exp); local; local = TREE_CHAIN (local))
      if (DECL_INITIAL (local) != 0
          && calls_function_1 (DECL_INITIAL (local), which))
        return 1;
      }
      {
    register tree subblock;

    for (subblock = BLOCK_SUBBLOCKS (exp);
         subblock;
         subblock = TREE_CHAIN (subblock))
      if (calls_function_1 (subblock, which))
        return 1;
      }
      return 0;

    case METHOD_CALL_EXPR:
      length = 3;
      break;

    case WITH_CLEANUP_EXPR:
      length = 1;
      break;

    case RTL_EXPR:
      return 0;
    }

  for (i = 0; i < length; i++)
    if (TREE_OPERAND (exp, i) != 0
    && calls_function_1 (TREE_OPERAND (exp, i), which))
      return 1;

  return 0;
}

/* Force FUNEXP into a form suitable for the address of a CALL,
   and return that as an rtx.  Also load the static chain register
   if FNDECL is a nested function.

   CALL_FUSAGE points to a variable holding the prospective
   CALL_INSN_FUNCTION_USAGE information.  */

rtx
prepare_call_address (funexp, fndecl, call_fusage, reg_parm_seen)
     rtx funexp;
     tree fndecl;
     rtx *call_fusage;
     int reg_parm_seen;
{
  rtx static_chain_value = 0;

  funexp = protect_from_queue (funexp, 0);

  if (fndecl != 0)
    /* Get possible static chain value for nested function in C. */
    static_chain_value = lookup_static_chain (fndecl);

  /* Make a valid memory address and copy constants thru pseudo-regs,
     but not for a constant address if -fno-function-cse.  */
  if (GET_CODE (funexp) != SYMBOL_REF)
    funexp =
#ifdef SMALL_REGISTER_CLASSES
    /* If we are using registers for parameters, force the
     function address into a register now.  */
      reg_parm_seen ? force_not_mem (memory_address (FUNCTION_MODE, funexp))
            :
#endif
              memory_address (FUNCTION_MODE, funexp);
  else
    {
#ifndef NO_FUNCTION_CSE
      if (optimize && ! flag_no_function_cse)
#ifdef NO_RECURSIVE_FUNCTION_CSE
    if (fndecl != current_function_decl)
#endif
      funexp = force_reg (Pmode, funexp);
#endif
    }

  if (static_chain_value != 0)
    {
      emit_move_insn (static_chain_rtx, static_chain_value);

      use_reg (call_fusage, static_chain_rtx);
    }

  return funexp;
}

/* Generate instructions to call function FUNEXP,
   and optionally pop the results.
   The CALL_INSN is the first insn generated.

   FUNTYPE is the data type of the function, or, for a library call,
   the identifier for the name of the call.  This is given to the
   macro RETURN_POPS_ARGS to determine whether this function pops its own args.

   STACK_SIZE is the number of bytes of arguments on the stack,
   rounded up to STACK_BOUNDARY; zero if the size is variable.
   This is both to put into the call insn and
   to generate explicit popping code if necessary.

   STRUCT_VALUE_SIZE is the number of bytes wanted in a structure value.
   It is zero if this call doesn't want a structure value.

   NEXT_ARG_REG is the rtx that results from executing
     FUNCTION_ARG (args_so_far, VOIDmode, void_type_node, 1)
   just after all the args have had their registers assigned.
   This could be whatever you like, but normally it is the first
   arg-register beyond those used for args in this call,
   or 0 if all the arg-registers are used in this call.
   It is passed on to `gen_call' so you can put this info in the call insn.

   VALREG is a hard register in which a value is returned,
   or 0 if the call does not return a value.

   OLD_INHIBIT_DEFER_POP is the value that `inhibit_defer_pop' had before
   the args to this call were processed.
   We restore `inhibit_defer_pop' to that value.

   CALL_FUSAGE is either empty or an EXPR_LIST of USE expressions that
   denote registers used by the called function.

   IS_CONST is true if this is a `const' call.  */

static void
emit_call_1 (funexp, funtype, stack_size, struct_value_size, next_arg_reg,
         valreg, old_inhibit_defer_pop, call_fusage, is_const)
     rtx funexp;
     tree funtype;
     int stack_size;
     int struct_value_size;
     rtx next_arg_reg;
     rtx valreg;
     int old_inhibit_defer_pop;
     rtx call_fusage;
     int is_const;
{
  rtx stack_size_rtx = GEN_INT (stack_size);
  rtx struct_value_size_rtx = GEN_INT (struct_value_size);
  rtx call_insn;
  int already_popped = 0;

  /* Ensure address is valid.  SYMBOL_REF is already valid, so no need,
     and we don't want to load it into a register as an optimization,
     because prepare_call_address already did it if it should be done.  */
  if (GET_CODE (funexp) != SYMBOL_REF)
    funexp = memory_address (FUNCTION_MODE, funexp);

#ifndef ACCUMULATE_OUTGOING_ARGS
#if defined (HAVE_call_pop) && defined (HAVE_call_value_pop)
  if (HAVE_call_pop && HAVE_call_value_pop
      && (RETURN_POPS_ARGS (funtype, stack_size) > 0 || stack_size == 0))
    {
      rtx n_pop = GEN_INT (RETURN_POPS_ARGS (funtype, stack_size));
      rtx pat;

      /* If this subroutine pops its own args, record that in the call insn
     if possible, for the sake of frame pointer elimination.  */
      if (valreg)
    pat = gen_call_value_pop (valreg,
                  gen_rtx (MEM, FUNCTION_MODE, funexp),
                  stack_size_rtx, next_arg_reg, n_pop);
      else
    pat = gen_call_pop (gen_rtx (MEM, FUNCTION_MODE, funexp),
                stack_size_rtx, next_arg_reg, n_pop);

      emit_call_insn (pat);
      already_popped = 1;
    }
  else
#endif
#endif

#if defined (HAVE_call) && defined (HAVE_call_value)
  if (HAVE_call && HAVE_call_value)
    {
      if (valreg)
    emit_call_insn (gen_call_value (valreg,
                    gen_rtx (MEM, FUNCTION_MODE, funexp),
                    stack_size_rtx, next_arg_reg,
                    NULL_RTX));
      else
    emit_call_insn (gen_call (gen_rtx (MEM, FUNCTION_MODE, funexp),
                  stack_size_rtx, next_arg_reg,
                  struct_value_size_rtx));
    }
  else
#endif
    abort ();

  /* Find the CALL insn we just emitted.  */
  for (call_insn = get_last_insn ();
       call_insn && GET_CODE (call_insn) != CALL_INSN;
       call_insn = PREV_INSN (call_insn))
    ;

  if (! call_insn)
    abort ();

  /* Put the register usage information on the CALL.  If there is already
     some usage information, put ours at the end.  */
  if (CALL_INSN_FUNCTION_USAGE (call_insn))
    {
      rtx link;

      for (link = CALL_INSN_FUNCTION_USAGE (call_insn); XEXP (link, 1) != 0;
       link = XEXP (link, 1))
    ;

      XEXP (link, 1) = call_fusage;
    }
  else
    CALL_INSN_FUNCTION_USAGE (call_insn) = call_fusage;

  /* If this is a const call, then set the insn's unchanging bit.  */
  if (is_const)
    CONST_CALL_P (call_insn) = 1;

  /* Restore this now, so that we do defer pops for this call's args
     if the context of the call as a whole permits.  */
  inhibit_defer_pop = old_inhibit_defer_pop;

#ifndef ACCUMULATE_OUTGOING_ARGS
  /* If returning from the subroutine does not automatically pop the args,
     we need an instruction to pop them sooner or later.
     Perhaps do it now; perhaps just record how much space to pop later.

     If returning from the subroutine does pop the args, indicate that the
     stack pointer will be changed.  */

  if (stack_size != 0 && RETURN_POPS_ARGS (funtype, stack_size) > 0)
    {
      if (!already_popped)
    CALL_INSN_FUNCTION_USAGE (call_insn) =
       gen_rtx (EXPR_LIST, VOIDmode,
            gen_rtx (CLOBBER, VOIDmode, stack_pointer_rtx),
            CALL_INSN_FUNCTION_USAGE (call_insn));
      stack_size -= RETURN_POPS_ARGS (funtype, stack_size);
      stack_size_rtx = GEN_INT (stack_size);
    }

  if (stack_size != 0)
    {
      if (flag_defer_pop && inhibit_defer_pop == 0 && !is_const)
    pending_stack_adjust += stack_size;
      else
    adjust_stack (stack_size_rtx);
    }
#endif
}

/* Generate all the code for a function call
   and return an rtx for its value.
   Store the value in TARGET (specified as an rtx) if convenient.
   If the value is stored in TARGET then TARGET is returned.
   If IGNORE is nonzero, then we ignore the value of the function call.  */

rtx
expand_call (exp, target, ignore)
     tree exp;
     rtx target;
     int ignore;
{
  /* List of actual parameters.  */
  tree actparms = TREE_OPERAND (exp, 1);
  /* RTX for the function to be called.  */
  rtx funexp;
  /* Tree node for the function to be called (not the address!).  */
  tree funtree;
  /* Data type of the function.  */
  tree funtype;
  /* Declaration of the function being called,
     or 0 if the function is computed (not known by name).  */
  tree fndecl = 0;
  char *name = 0;

  /* Register in which non-BLKmode value will be returned,
     or 0 if no value or if value is BLKmode.  */
  rtx valreg;
  /* Address where we should return a BLKmode value;
     0 if value not BLKmode.  */
  rtx structure_value_addr = 0;
  /* Nonzero if that address is being passed by treating it as
     an extra, implicit first parameter.  Otherwise,
     it is passed by being copied directly into struct_value_rtx.  */
  int structure_value_addr_parm = 0;
  /* Size of aggregate value wanted, or zero if none wanted
     or if we are using the non-reentrant PCC calling convention
     or expecting the value in registers.  */
  int struct_value_size = 0;
  /* Nonzero if called function returns an aggregate in memory PCC style,
     by returning the address of where to find it.  */
  int pcc_struct_value = 0;

  /* Number of actual parameters in this call, including struct value addr.  */
  int num_actuals;
  /* Number of named args.  Args after this are anonymous ones
     and they must all go on the stack.  */
  int n_named_args;
  /* Count arg position in order args appear.  */
  int argpos;

  /* Vector of information about each argument.
     Arguments are numbered in the order they will be pushed,
     not the order they are written.  */
  struct arg_data *args;

  /* Total size in bytes of all the stack-parms scanned so far.  */
  struct args_size args_size;
  /* Size of arguments before any adjustments (such as rounding).  */
  struct args_size original_args_size;
  /* Data on reg parms scanned so far.  */
  CUMULATIVE_ARGS args_so_far;
  /* Nonzero if a reg parm has been scanned.  */
  int reg_parm_seen;
  /* Nonzero if this is an indirect function call.  */
  int current_call_is_indirect = 0;

  /* Nonzero if we must avoid push-insns in the args for this call.
     If stack space is allocated for register parameters, but not by the
     caller, then it is preallocated in the fixed part of the stack frame.
     So the entire argument block must then be preallocated (i.e., we
     ignore PUSH_ROUNDING in that case).  */

#if defined(REG_PARM_STACK_SPACE) && ! defined(OUTGOING_REG_PARM_STACK_SPACE)
  int must_preallocate = 1;
#else
#ifdef PUSH_ROUNDING
  int must_preallocate = 0;
#else
  int must_preallocate = 1;
#endif
#endif

  /* Size of the stack reserved for parameter registers.  */
  int reg_parm_stack_space = 0;

  /* 1 if scanning parms front to back, -1 if scanning back to front.  */
  int inc;
  /* Address of space preallocated for stack parms
     (on machines that lack push insns), or 0 if space not preallocated.  */
  rtx argblock = 0;

  /* Nonzero if it is plausible that this is a call to alloca.  */
  int may_be_alloca;
  /* Nonzero if this is a call to setjmp or a related function.  */
  int returns_twice;
  /* Nonzero if this is a call to `longjmp'.  */
  int is_longjmp;
  /* Nonzero if this is a call to an inline function.  */
  int is_integrable = 0;
  /* Nonzero if this is a call to a `const' function.
     Note that only explicitly named functions are handled as `const' here.  */
  int is_const = 0;
  /* Nonzero if this is a call to a `volatile' function.  */
  int is_volatile = 0;
#if defined(ACCUMULATE_OUTGOING_ARGS) && defined(REG_PARM_STACK_SPACE)
  /* Define the boundary of the register parm stack space that needs to be
     save, if any.  */
  int low_to_save = -1, high_to_save;
  rtx save_area = 0;        /* Place that it is saved */
#endif

#ifdef ACCUMULATE_OUTGOING_ARGS
  int initial_highest_arg_in_use = highest_outgoing_arg_in_use;
  char *initial_stack_usage_map = stack_usage_map;
#endif

  rtx old_stack_level = 0;
  int old_pending_adj = 0;
  int old_stack_arg_under_construction;
  int old_inhibit_defer_pop = inhibit_defer_pop;
  tree old_cleanups = cleanups_this_call;
  rtx call_fusage = 0;
  register tree p;
  register int i, j;

  /* See if we can find a DECL-node for the actual function.
     As a result, decide whether this is a call to an integrable function.  */

  p = TREE_OPERAND (exp, 0);
  if (TREE_CODE (p) == ADDR_EXPR)
    {
      fndecl = TREE_OPERAND (p, 0);
      if (TREE_CODE (fndecl) != FUNCTION_DECL)
    fndecl = 0;
      else
    {
      if (!flag_no_inline
          && fndecl != current_function_decl
          && DECL_SAVED_INSNS (fndecl))
        is_integrable = 1;
      else if (! TREE_ADDRESSABLE (fndecl))
        {
          /* In case this function later becomes inlinable,
         record that there was already a non-inline call to it.

         Use abstraction instead of setting TREE_ADDRESSABLE
         directly.  */
          if (DECL_INLINE (fndecl) && warn_inline && !flag_no_inline)
        warning_with_decl (fndecl, "can't inline call to `%s'");
          mark_addressable (fndecl);
        }

      if (TREE_READONLY (fndecl) && ! TREE_THIS_VOLATILE (fndecl)
          && TYPE_MODE (TREE_TYPE (exp)) != VOIDmode)
        is_const = 1;

      if (TREE_THIS_VOLATILE (fndecl))
        is_volatile = 1;
    }
    }

  /* If we don't have specific function to call, see if we have a
     constant or `noreturn' function from the type.  */
  if (fndecl == 0)
    {
      is_const = TREE_READONLY (TREE_TYPE (TREE_TYPE (p)));
      is_volatile = TREE_THIS_VOLATILE (TREE_TYPE (TREE_TYPE (p)));
    }

#ifdef REG_PARM_STACK_SPACE
#ifdef MAYBE_REG_PARM_STACK_SPACE
  reg_parm_stack_space = MAYBE_REG_PARM_STACK_SPACE;
#else
  reg_parm_stack_space = REG_PARM_STACK_SPACE (fndecl);
#endif
#endif

  /* Warn if this value is an aggregate type,
     regardless of which calling convention we are using for it.  */
  if (warn_aggregate_return && AGGREGATE_TYPE_P (TREE_TYPE (exp)))
    warning ("function call has aggregate value");

  /* Set up a place to return a structure.  */

  /* Cater to broken compilers.  */
  if (aggregate_value_p (exp))
    {
      /* This call returns a big structure.  */
      is_const = 0;

#ifdef PCC_STATIC_STRUCT_RETURN
      {
    pcc_struct_value = 1;
    /* Easier than making that case work right.  */
    if (is_integrable)
      {
        /* In case this is a static function, note that it has been
           used.  */
        if (! TREE_ADDRESSABLE (fndecl))
          mark_addressable (fndecl);
        is_integrable = 0;
      }
      }
#else /* not PCC_STATIC_STRUCT_RETURN */
      {
    struct_value_size = int_size_in_bytes (TREE_TYPE (exp));

    if (target && GET_CODE (target) == MEM)
      structure_value_addr = XEXP (target, 0);
    else
      {
        /* Assign a temporary on the stack to hold the value.  */

        /* For variable-sized objects, we must be called with a target
           specified.  If we were to allocate space on the stack here,
           we would have no way of knowing when to free it.  */

        if (struct_value_size < 0)
          abort ();

        structure_value_addr
          = XEXP (assign_stack_temp (BLKmode, struct_value_size, 1), 0);
        target = 0;
      }
      }
#endif /* not PCC_STATIC_STRUCT_RETURN */
    }

  /* If called function is inline, try to integrate it.  */

  if (is_integrable)
    {
      rtx temp;
      rtx before_call = get_last_insn ();

      temp = expand_inline_function (fndecl, actparms, target,
                     ignore, TREE_TYPE (exp),
                     structure_value_addr);

      /* If inlining succeeded, return.  */
      if ((HOST_WIDE_INT) temp != -1)
    {
      if (flag_short_temps)
        {
          /* Perform all cleanups needed for the arguments of this
         call (i.e. destructors in C++).  It is ok if these
         destructors clobber RETURN_VALUE_REG, because the
         only time we care about this is when TARGET is that
         register.  But in C++, we take care to never return
         that register directly.  */
          expand_cleanups_to (old_cleanups);
        }

#ifdef ACCUMULATE_OUTGOING_ARGS
      /* If the outgoing argument list must be preserved, push
         the stack before executing the inlined function if it
         makes any calls.  */

      for (i = reg_parm_stack_space - 1; i >= 0; i--)
        if (i < highest_outgoing_arg_in_use && stack_usage_map[i] != 0)
          break;

      if (stack_arg_under_construction || i >= 0)
        {
          rtx insn = NEXT_INSN (before_call), seq;

          /* Look for a call in the inline function code.
         If OUTGOING_ARGS_SIZE (DECL_SAVED_INSNS (fndecl)) is
         nonzero then there is a call and it is not necessary
         to scan the insns.  */

          if (OUTGOING_ARGS_SIZE (DECL_SAVED_INSNS (fndecl)) == 0)
        for (; insn; insn = NEXT_INSN (insn))
          if (GET_CODE (insn) == CALL_INSN)
            break;

          if (insn)
        {
          /* Reserve enough stack space so that the largest
             argument list of any function call in the inline
             function does not overlap the argument list being
             evaluated.  This is usually an overestimate because
             allocate_dynamic_stack_space reserves space for an
             outgoing argument list in addition to the requested
             space, but there is no way to ask for stack space such
             that an argument list of a certain length can be
             safely constructed.  */

          int adjust = OUTGOING_ARGS_SIZE (DECL_SAVED_INSNS (fndecl));
#ifdef REG_PARM_STACK_SPACE
          /* Add the stack space reserved for register arguments
             in the inline function.  What is really needed is the
             largest value of reg_parm_stack_space in the inline
             function, but that is not available.  Using the current
             value of reg_parm_stack_space is wrong, but gives
             correct results on all supported machines.  */
          adjust += reg_parm_stack_space;
#endif
          start_sequence ();
          emit_stack_save (SAVE_BLOCK, &old_stack_level, NULL_RTX);
          allocate_dynamic_stack_space (GEN_INT (adjust),
                        NULL_RTX, BITS_PER_UNIT);
          seq = get_insns ();
          end_sequence ();
          emit_insns_before (seq, NEXT_INSN (before_call));
          emit_stack_restore (SAVE_BLOCK, old_stack_level, NULL_RTX);
        }
        }
#endif

      /* If the result is equivalent to TARGET, return TARGET to simplify
         checks in store_expr.  They can be equivalent but not equal in the
         case of a function that returns BLKmode.  */
      if (temp != target && rtx_equal_p (temp, target))
        return target;
      return temp;
    }

      /* If inlining failed, mark FNDECL as needing to be compiled
     separately after all.  If function was declared inline,
     give a warning.  */
      if (DECL_INLINE (fndecl) && warn_inline && !flag_no_inline
      && ! TREE_ADDRESSABLE (fndecl))
    warning_with_decl (fndecl, "can't inline call to `%s'");
      mark_addressable (fndecl);
    }

  /* When calling a const function, we must pop the stack args right away,
     so that the pop is deleted or moved with the call.  */
  if (is_const)
    NO_DEFER_POP;

  function_call_count++;

  if (fndecl && DECL_NAME (fndecl))
    name = IDENTIFIER_POINTER (DECL_NAME (fndecl));

  /* On some machines (such as the PA) indirect calls have a different
     calling convention than normal calls.  FUNCTION_ARG in the target
     description can look at current_call_is_indirect to determine which
     calling convention to use.  */
  current_call_is_indirect = (fndecl == 0);
#if 0
    = TREE_CODE (TREE_OPERAND (exp, 0)) == NON_LVALUE_EXPR ? 1 : 0;
#endif

#if 0
  /* Unless it's a call to a specific function that isn't alloca,
     if it has one argument, we must assume it might be alloca.  */

  may_be_alloca =
    (!(fndecl != 0 && strcmp (name, "alloca"))
     && actparms != 0
     && TREE_CHAIN (actparms) == 0);
#else
  /* We assume that alloca will always be called by name.  It
     makes no sense to pass it as a pointer-to-function to
     anything that does not understand its behavior.  */
  may_be_alloca =
    (name && ((IDENTIFIER_LENGTH (DECL_NAME (fndecl)) == 6
         && name[0] == 'a'
         && ! strcmp (name, "alloca"))
        || (IDENTIFIER_LENGTH (DECL_NAME (fndecl)) == 16
            && name[0] == '_'
            && ! strcmp (name, "__builtin_alloca"))));
#endif

  /* See if this is a call to a function that can return more than once
     or a call to longjmp.  */

  returns_twice = 0;
  is_longjmp = 0;

  if (name != 0 && IDENTIFIER_LENGTH (DECL_NAME (fndecl)) <= 15)
    {
      char *tname = name;

      /* Disregard prefix _, __ or __x.  */
      if (name[0] == '_')
    {
      if (name[1] == '_' && name[2] == 'x')
        tname += 3;
      else if (name[1] == '_')
        tname += 2;
      else
        tname += 1;
    }

      if (tname[0] == 's')
    {
      returns_twice
        = ((tname[1] == 'e'
        && (! strcmp (tname, "setjmp")
            || ! strcmp (tname, "setjmp_syscall")))
           || (tname[1] == 'i'
           && ! strcmp (tname, "sigsetjmp"))
           || (tname[1] == 'a'
           && ! strcmp (tname, "savectx")));
      if (tname[1] == 'i'
          && ! strcmp (tname, "siglongjmp"))
        is_longjmp = 1;
    }
      else if ((tname[0] == 'q' && tname[1] == 's'
        && ! strcmp (tname, "qsetjmp"))
           || (tname[0] == 'v' && tname[1] == 'f'
           && ! strcmp (tname, "vfork")))
    returns_twice = 1;

      else if (tname[0] == 'l' && tname[1] == 'o'
           && ! strcmp (tname, "longjmp"))
    is_longjmp = 1;
    }

  if (may_be_alloca)
    current_function_calls_alloca = 1;

  /* Don't let pending stack adjusts add up to too much.
     Also, do all pending adjustments now
     if there is any chance this might be a call to alloca.  */

  if (pending_stack_adjust >= 32
      || (pending_stack_adjust > 0 && may_be_alloca))
    do_pending_stack_adjust ();

  /* Operand 0 is a pointer-to-function; get the type of the function.  */
  funtype = TREE_TYPE (TREE_OPERAND (exp, 0));
  if (TREE_CODE (funtype) != POINTER_TYPE)
    abort ();
  funtype = TREE_TYPE (funtype);

  /* Push the temporary stack slot level so that we can free any temporaries
     we make.  */
  push_temp_slots ();

  /* Start updating where the next arg would go.  */
  INIT_CUMULATIVE_ARGS (args_so_far, funtype, NULL_RTX);

  /* If struct_value_rtx is 0, it means pass the address
     as if it were an extra parameter.  */
  if (structure_value_addr && struct_value_rtx == 0)
    {
      /* If structure_value_addr is a REG other than
     virtual_outgoing_args_rtx, we can use always use it.  If it
     is not a REG, we must always copy it into a register.
     If it is virtual_outgoing_args_rtx, we must copy it to another
     register in some cases.  */
      rtx temp = (GET_CODE (structure_value_addr) != REG
#ifdef ACCUMULATE_OUTGOING_ARGS
          || (stack_arg_under_construction
              && structure_value_addr == virtual_outgoing_args_rtx)
#endif
          ? copy_addr_to_reg (structure_value_addr)
          : structure_value_addr);

      actparms
    = tree_cons (error_mark_node,
             make_tree (build_pointer_type (TREE_TYPE (funtype)),
                temp),
             actparms);
      structure_value_addr_parm = 1;
    }

  /* Count the arguments and set NUM_ACTUALS.  */
  for (p = actparms, i = 0; p; p = TREE_CHAIN (p)) i++;
  num_actuals = i;

  /* Compute number of named args.
     Normally, don't include the last named arg if anonymous args follow.
     (If no anonymous args follow, the result of list_length
     is actually one too large.)

     If SETUP_INCOMING_VARARGS is defined, this machine will be able to
     place unnamed args that were passed in registers into the stack.  So
     treat all args as named.  This allows the insns emitting for a specific
     argument list to be independent of the function declaration.

     If SETUP_INCOMING_VARARGS is not defined, we do not have any reliable
     way to pass unnamed args in registers, so we must force them into
     memory.  */
#ifndef SETUP_INCOMING_VARARGS
  if (TYPE_ARG_TYPES (funtype) != 0)
    n_named_args
      = list_length (TYPE_ARG_TYPES (funtype)) - 1
    /* Count the struct value address, if it is passed as a parm.  */
    + structure_value_addr_parm;
  else
#endif
    /* If we know nothing, treat all args as named.  */
    n_named_args = num_actuals;

  /* Make a vector to hold all the information about each arg.  */
  args = (struct arg_data *) alloca (num_actuals * sizeof (struct arg_data));
  bzero ((char *) args, num_actuals * sizeof (struct arg_data));

  args_size.constant = 0;
  args_size.var = 0;

  /* In this loop, we consider args in the order they are written.
     We fill up ARGS from the front of from the back if necessary
     so that in any case the first arg to be pushed ends up at the front.  */

#ifdef PUSH_ARGS_REVERSED
  i = num_actuals - 1, inc = -1;
  /* In this case, must reverse order of args
     so that we compute and push the last arg first.  */
#else
  i = 0, inc = 1;
#endif

  /* I counts args in order (to be) pushed; ARGPOS counts in order written.  */
  for (p = actparms, argpos = 0; p; p = TREE_CHAIN (p), i += inc, argpos++)
    {
      tree type = TREE_TYPE (TREE_VALUE (p));
      int unsignedp;
      enum machine_mode mode;

      args[i].tree_value = TREE_VALUE (p);

      /* Replace erroneous argument with constant zero.  */
      if (type == error_mark_node || TYPE_SIZE (type) == 0)
    args[i].tree_value = integer_zero_node, type = integer_type_node;

      /* If TYPE is a transparent union, pass things the way we would
     pass the first field of the union.  We have already verified that
     the modes are the same.  */
      if (TYPE_TRANSPARENT_UNION (type))
    type = TREE_TYPE (TYPE_FIELDS (type));

      /* Decide where to pass this arg.

     args[i].reg is nonzero if all or part is passed in registers.

     args[i].partial is nonzero if part but not all is passed in registers,
     and the exact value says how many words are passed in registers.

     args[i].pass_on_stack is nonzero if the argument must at least be
     computed on the stack.  It may then be loaded back into registers
     if args[i].reg is nonzero.

     These decisions are driven by the FUNCTION_... macros and must agree
     with those made by function.c.  */

      /* See if this argument should be passed by invisible reference.  */
      if ((TREE_CODE (TYPE_SIZE (type)) != INTEGER_CST
       && contains_placeholder_p (TYPE_SIZE (type)))
      || TYPE_NEEDS_CONSTRUCTING (type)
#ifdef FUNCTION_ARG_PASS_BY_REFERENCE
      || FUNCTION_ARG_PASS_BY_REFERENCE (args_so_far, TYPE_MODE (type),
                         type, argpos < n_named_args)
#endif
      )
    {
#ifdef FUNCTION_ARG_CALLEE_COPIES
      if (FUNCTION_ARG_CALLEE_COPIES (args_so_far, TYPE_MODE (type), type,
                      argpos < n_named_args)
          /* If it's in a register, we must make a copy of it too.  */
          /* ??? Is this a sufficient test?  Is there a better one? */
          && !(TREE_CODE (args[i].tree_value) == VAR_DECL
           && REG_P (DECL_RTL (args[i].tree_value))))
        {
          args[i].tree_value = build1 (ADDR_EXPR,
                       build_pointer_type (type),
                       args[i].tree_value);
          type = build_pointer_type (type);
        }
      else
#endif
        {
          /* We make a copy of the object and pass the address to the
         function being called.  */
          rtx copy;

          if (TYPE_SIZE (type) == 0
          || TREE_CODE (TYPE_SIZE (type)) != INTEGER_CST)
        {
          /* This is a variable-sized object.  Make space on the stack
             for it.  */
          rtx size_rtx = expr_size (TREE_VALUE (p));

          if (old_stack_level == 0)
            {
              emit_stack_save (SAVE_BLOCK, &old_stack_level, NULL_RTX);
              old_pending_adj = pending_stack_adjust;
              pending_stack_adjust = 0;
            }

          copy = gen_rtx (MEM, BLKmode,
                  allocate_dynamic_stack_space (size_rtx,
                                NULL_RTX,
                                TYPE_ALIGN (type)));
        }
          else
        {
          int size = int_size_in_bytes (type);
          copy = assign_stack_temp (TYPE_MODE (type), size, 1);
        }

          MEM_IN_STRUCT_P (copy) = AGGREGATE_TYPE_P (type);

          store_expr (args[i].tree_value, copy, 0);

          args[i].tree_value = build1 (ADDR_EXPR,
                       build_pointer_type (type),
                       make_tree (type, copy));
          type = build_pointer_type (type);
        }
    }

      mode = TYPE_MODE (type);
      unsignedp = TREE_UNSIGNED (type);

#ifdef PROMOTE_FUNCTION_ARGS
      mode = promote_mode (type, mode, &unsignedp, 1);
#endif

      args[i].unsignedp = unsignedp;
      args[i].mode = mode;
      args[i].reg = FUNCTION_ARG (args_so_far, mode, type,
                  argpos < n_named_args);
#ifdef FUNCTION_ARG_PARTIAL_NREGS
      if (args[i].reg)
    args[i].partial
      = FUNCTION_ARG_PARTIAL_NREGS (args_so_far, mode, type,
                    argpos < n_named_args);
#endif

      args[i].pass_on_stack = MUST_PASS_IN_STACK (mode, type);

      /* If FUNCTION_ARG returned an (expr_list (nil) FOO), it means that
     we are to pass this arg in the register(s) designated by FOO, but
     also to pass it in the stack.  */
      if (args[i].reg && GET_CODE (args[i].reg) == EXPR_LIST
      && XEXP (args[i].reg, 0) == 0)
    args[i].pass_on_stack = 1, args[i].reg = XEXP (args[i].reg, 1);

      /* If this is an addressable type, we must preallocate the stack
     since we must evaluate the object into its final location.

     If this is to be passed in both registers and the stack, it is simpler
     to preallocate.  */
      if (TREE_ADDRESSABLE (type)
      || (args[i].pass_on_stack && args[i].reg != 0))
    must_preallocate = 1;

      /* If this is an addressable type, we cannot pre-evaluate it.  Thus,
     we cannot consider this function call constant.  */
      if (TREE_ADDRESSABLE (type))
    is_const = 0;

      /* Compute the stack-size of this argument.  */
      if (args[i].reg == 0 || args[i].partial != 0
#ifdef REG_PARM_STACK_SPACE
      || reg_parm_stack_space > 0
#endif
      || args[i].pass_on_stack)
    locate_and_pad_parm (mode, type,
#ifdef STACK_PARMS_IN_REG_PARM_AREA
                 1,
#else
                 args[i].reg != 0,
#endif
                 fndecl, &args_size, &args[i].offset,
                 &args[i].size);

#ifndef ARGS_GROW_DOWNWARD
      args[i].slot_offset = args_size;
#endif

#ifndef REG_PARM_STACK_SPACE
      /* If a part of the arg was put into registers,
     don't include that part in the amount pushed.  */
      if (! args[i].pass_on_stack)
    args[i].size.constant -= ((args[i].partial * UNITS_PER_WORD)
                  / (PARM_BOUNDARY / BITS_PER_UNIT)
                  * (PARM_BOUNDARY / BITS_PER_UNIT));
#endif

      /* Update ARGS_SIZE, the total stack space for args so far.  */

      args_size.constant += args[i].size.constant;
      if (args[i].size.var)
    {
      ADD_PARM_SIZE (args_size, args[i].size.var);
    }

      /* Since the slot offset points to the bottom of the slot,
     we must record it after incrementing if the args grow down.  */
#ifdef ARGS_GROW_DOWNWARD
      args[i].slot_offset = args_size;

      args[i].slot_offset.constant = -args_size.constant;
      if (args_size.var)
    {
      SUB_PARM_SIZE (args[i].slot_offset, args_size.var);
    }
#endif

      /* Increment ARGS_SO_FAR, which has info about which arg-registers
     have been used, etc.  */

      FUNCTION_ARG_ADVANCE (args_so_far, TYPE_MODE (type), type,
                argpos < n_named_args);
    }

#ifdef FINAL_REG_PARM_STACK_SPACE
  reg_parm_stack_space = FINAL_REG_PARM_STACK_SPACE (args_size.constant,
                             args_size.var);
#endif

  /* Compute the actual size of the argument block required.  The variable
     and constant sizes must be combined, the size may have to be rounded,
     and there may be a minimum required size.  */

  original_args_size = args_size;
  if (args_size.var)
    {
      /* If this function requires a variable-sized argument list, don't try to
     make a cse'able block for this call.  We may be able to do this
     eventually, but it is too complicated to keep track of what insns go
     in the cse'able block and which don't.  */

      is_const = 0;
      must_preallocate = 1;

      args_size.var = ARGS_SIZE_TREE (args_size);
      args_size.constant = 0;

#ifdef STACK_BOUNDARY
      if (STACK_BOUNDARY != BITS_PER_UNIT)
    args_size.var = round_up (args_size.var, STACK_BYTES);
#endif

#ifdef REG_PARM_STACK_SPACE
      if (reg_parm_stack_space > 0)
    {
      args_size.var
        = size_binop (MAX_EXPR, args_size.var,
              size_int (REG_PARM_STACK_SPACE (fndecl)));

#ifndef OUTGOING_REG_PARM_STACK_SPACE
      /* The area corresponding to register parameters is not to count in
         the size of the block we need.  So make the adjustment.  */
      args_size.var
        = size_binop (MINUS_EXPR, args_size.var,
              size_int (reg_parm_stack_space));
#endif
    }
#endif
    }
  else
    {
#ifdef STACK_BOUNDARY
      args_size.constant = (((args_size.constant + (STACK_BYTES - 1))
                 / STACK_BYTES) * STACK_BYTES);
#endif

#ifdef REG_PARM_STACK_SPACE
      args_size.constant = MAX (args_size.constant,
                reg_parm_stack_space);
#ifdef MAYBE_REG_PARM_STACK_SPACE
      if (reg_parm_stack_space == 0)
    args_size.constant = 0;
#endif
#ifndef OUTGOING_REG_PARM_STACK_SPACE
      args_size.constant -= reg_parm_stack_space;
#endif
#endif
    }

  /* See if we have or want to preallocate stack space.

     If we would have to push a partially-in-regs parm
     before other stack parms, preallocate stack space instead.

     If the size of some parm is not a multiple of the required stack
     alignment, we must preallocate.

     If the total size of arguments that would otherwise create a copy in
     a temporary (such as a CALL) is more than half the total argument list
     size, preallocation is faster.

     Another reason to preallocate is if we have a machine (like the m88k)
     where stack alignment is required to be maintained between every
     pair of insns, not just when the call is made.  However, we assume here
     that such machines either do not have push insns (and hence preallocation
     would occur anyway) or the problem is taken care of with
     PUSH_ROUNDING.  */

  if (! must_preallocate)
    {
      int partial_seen = 0;
      int copy_to_evaluate_size = 0;

      for (i = 0; i < num_actuals && ! must_preallocate; i++)
    {
      if (args[i].partial > 0 && ! args[i].pass_on_stack)
        partial_seen = 1;
      else if (partial_seen && args[i].reg == 0)
        must_preallocate = 1;

      if (TYPE_MODE (TREE_TYPE (args[i].tree_value)) == BLKmode
          && (TREE_CODE (args[i].tree_value) == CALL_EXPR
          || TREE_CODE (args[i].tree_value) == TARGET_EXPR
          || TREE_CODE (args[i].tree_value) == COND_EXPR
          || TREE_ADDRESSABLE (TREE_TYPE (args[i].tree_value))))
        copy_to_evaluate_size
          += int_size_in_bytes (TREE_TYPE (args[i].tree_value));
    }

      if (copy_to_evaluate_size * 2 >= args_size.constant
      && args_size.constant > 0)
    must_preallocate = 1;
    }

  /* If the structure value address will reference the stack pointer, we must
     stabilize it.  We don't need to do this if we know that we are not going
     to adjust the stack pointer in processing this call.  */

  if (structure_value_addr
      && (reg_mentioned_p (virtual_stack_dynamic_rtx, structure_value_addr)
       || reg_mentioned_p (virtual_outgoing_args_rtx, structure_value_addr))
      && (args_size.var
#ifndef ACCUMULATE_OUTGOING_ARGS
      || args_size.constant
#endif
      ))
    structure_value_addr = copy_to_reg (structure_value_addr);

  /* If this function call is cse'able, precompute all the parameters.
     Note that if the parameter is constructed into a temporary, this will
     cause an additional copy because the parameter will be constructed
     into a temporary location and then copied into the outgoing arguments.
     If a parameter contains a call to alloca and this function uses the
     stack, precompute the parameter.  */

  /* If we preallocated the stack space, and some arguments must be passed
     on the stack, then we must precompute any parameter which contains a
     function call which will store arguments on the stack.
     Otherwise, evaluating the parameter may clobber previous parameters
     which have already been stored into the stack.  */

  for (i = 0; i < num_actuals; i++)
    if (is_const
    || ((args_size.var != 0 || args_size.constant != 0)
        && calls_function (args[i].tree_value, 1))
    || (must_preallocate && (args_size.var != 0 || args_size.constant != 0)
        && calls_function (args[i].tree_value, 0)))
      {
    push_temp_slots ();

    args[i].initial_value = args[i].value
      = expand_expr (args[i].tree_value, NULL_RTX, VOIDmode, 0);

    if (TYPE_MODE (TREE_TYPE (args[i].tree_value)) != args[i].mode)
      args[i].value
        = convert_modes (args[i].mode,
                 TYPE_MODE (TREE_TYPE (args[i].tree_value)),
                 args[i].value, args[i].unsignedp);

    preserve_temp_slots (args[i].value);
    pop_temp_slots ();

    /* ANSI doesn't require a sequence point here,
       but PCC has one, so this will avoid some problems.  */
    emit_queue ();
      }

  /* Now we are about to start emitting insns that can be deleted
     if a libcall is deleted.  */
  if (is_const)
    start_sequence ();

  /* If we have no actual push instructions, or shouldn't use them,
     make space for all args right now.  */

  if (args_size.var != 0)
    {
      if (old_stack_level == 0)
    {
      emit_stack_save (SAVE_BLOCK, &old_stack_level, NULL_RTX);
      old_pending_adj = pending_stack_adjust;
      pending_stack_adjust = 0;
#ifdef ACCUMULATE_OUTGOING_ARGS
      /* stack_arg_under_construction says whether a stack arg is
         being constructed at the old stack level.  Pushing the stack
         gets a clean outgoing argument block.  */
      old_stack_arg_under_construction = stack_arg_under_construction;
      stack_arg_under_construction = 0;
#endif
    }
      argblock = push_block (ARGS_SIZE_RTX (args_size), 0, 0);
    }
  else
    {
      /* Note that we must go through the motions of allocating an argument
     block even if the size is zero because we may be storing args
     in the area reserved for register arguments, which may be part of
     the stack frame.  */

      int needed = args_size.constant;

      /* Store the maximum argument space used.  It will be pushed by the
     prologue (if ACCUMULATE_OUTGOING_ARGS, or stack overflow checking). */

      if (needed > current_function_outgoing_args_size)
    current_function_outgoing_args_size = needed;

      if (must_preallocate)
    {
#ifdef ACCUMULATE_OUTGOING_ARGS
      /* Since the stack pointer will never be pushed, it is possible for
         the evaluation of a parm to clobber something we have already
         written to the stack.  Since most function calls on RISC machines
         do not use the stack, this is uncommon, but must work correctly.

         Therefore, we save any area of the stack that was already written
         and that we are using.  Here we set up to do this by making a new
         stack usage map from the old one.  The actual save will be done
         by store_one_arg.

         Another approach might be to try to reorder the argument
         evaluations to avoid this conflicting stack usage.  */

#if defined(REG_PARM_STACK_SPACE) && ! defined(OUTGOING_REG_PARM_STACK_SPACE)
      /* Since we will be writing into the entire argument area, the
         map must be allocated for its entire size, not just the part that
         is the responsibility of the caller.  */
      needed += reg_parm_stack_space;
#endif

#ifdef ARGS_GROW_DOWNWARD
      highest_outgoing_arg_in_use = MAX (initial_highest_arg_in_use,
                         needed + 1);
#else
      highest_outgoing_arg_in_use = MAX (initial_highest_arg_in_use,
                         needed);
#endif
      stack_usage_map = (char *) alloca (highest_outgoing_arg_in_use);

      if (initial_highest_arg_in_use)
        bcopy (initial_stack_usage_map, stack_usage_map,
           initial_highest_arg_in_use);

      if (initial_highest_arg_in_use != highest_outgoing_arg_in_use)
        bzero (&stack_usage_map[initial_highest_arg_in_use],
           highest_outgoing_arg_in_use - initial_highest_arg_in_use);
      needed = 0;

      /* The address of the outgoing argument list must not be copied to a
         register here, because argblock would be left pointing to the
         wrong place after the call to allocate_dynamic_stack_space below.
         */

      argblock = virtual_outgoing_args_rtx;

#else /* not ACCUMULATE_OUTGOING_ARGS */
      if (inhibit_defer_pop == 0)
        {
          /* Try to reuse some or all of the pending_stack_adjust
         to get this space.  Maybe we can avoid any pushing.  */
          if (needed > pending_stack_adjust)
        {
          needed -= pending_stack_adjust;
          pending_stack_adjust = 0;
        }
          else
        {
          pending_stack_adjust -= needed;
          needed = 0;
        }
        }
      /* Special case this because overhead of `push_block' in this
         case is non-trivial.  */
      if (needed == 0)
        argblock = virtual_outgoing_args_rtx;
      else
        argblock = push_block (GEN_INT (needed), 0, 0);

      /* We only really need to call `copy_to_reg' in the case where push
         insns are going to be used to pass ARGBLOCK to a function
         call in ARGS.  In that case, the stack pointer changes value
         from the allocation point to the call point, and hence
         the value of VIRTUAL_OUTGOING_ARGS_RTX changes as well.
         But might as well always do it.  */
      argblock = copy_to_reg (argblock);
#endif /* not ACCUMULATE_OUTGOING_ARGS */
    }
    }

#ifdef ACCUMULATE_OUTGOING_ARGS
  /* The save/restore code in store_one_arg handles all cases except one:
     a constructor call (including a C function returning a BLKmode struct)
     to initialize an argument.  */
  if (stack_arg_under_construction)
    {
#if defined(REG_PARM_STACK_SPACE) && ! defined(OUTGOING_REG_PARM_STACK_SPACE)
      rtx push_size = GEN_INT (reg_parm_stack_space + args_size.constant);
#else
      rtx push_size = GEN_INT (args_size.constant);
#endif
      if (old_stack_level == 0)
    {
      emit_stack_save (SAVE_BLOCK, &old_stack_level, NULL_RTX);
      old_pending_adj = pending_stack_adjust;
      pending_stack_adjust = 0;
      /* stack_arg_under_construction says whether a stack arg is
         being constructed at the old stack level.  Pushing the stack
         gets a clean outgoing argument block.  */
      old_stack_arg_under_construction = stack_arg_under_construction;
      stack_arg_under_construction = 0;
      /* Make a new map for the new argument list.  */
      stack_usage_map = (char *)alloca (highest_outgoing_arg_in_use);
      bzero (stack_usage_map, highest_outgoing_arg_in_use);
      highest_outgoing_arg_in_use = 0;
    }
      allocate_dynamic_stack_space (push_size, NULL_RTX, BITS_PER_UNIT);
    }
  /* If argument evaluation might modify the stack pointer, copy the
     address of the argument list to a register.  */
  for (i = 0; i < num_actuals; i++)
    if (args[i].pass_on_stack)
      {
    argblock = copy_addr_to_reg (argblock);
    break;
      }
#endif


  /* If we preallocated stack space, compute the address of each argument.
     We need not ensure it is a valid memory address here; it will be
     validized when it is used.  */
  if (argblock)
    {
      rtx arg_reg = argblock;
      int arg_offset = 0;

      if (GET_CODE (argblock) == PLUS)
    arg_reg = XEXP (argblock, 0), arg_offset = INTVAL (XEXP (argblock, 1));

      for (i = 0; i < num_actuals; i++)
    {
      rtx offset = ARGS_SIZE_RTX (args[i].offset);
      rtx slot_offset = ARGS_SIZE_RTX (args[i].slot_offset);
      rtx addr;

      /* Skip this parm if it will not be passed on the stack.  */
      if (! args[i].pass_on_stack && args[i].reg != 0)
        continue;

      if (GET_CODE (offset) == CONST_INT)
        addr = plus_constant (arg_reg, INTVAL (offset));
      else
        addr = gen_rtx (PLUS, Pmode, arg_reg, offset);

      addr = plus_constant (addr, arg_offset);
      args[i].stack = gen_rtx (MEM, args[i].mode, addr);
      MEM_IN_STRUCT_P (args[i].stack)
        = AGGREGATE_TYPE_P (TREE_TYPE (args[i].tree_value));

      if (GET_CODE (slot_offset) == CONST_INT)
        addr = plus_constant (arg_reg, INTVAL (slot_offset));
      else
        addr = gen_rtx (PLUS, Pmode, arg_reg, slot_offset);

      addr = plus_constant (addr, arg_offset);
      args[i].stack_slot = gen_rtx (MEM, args[i].mode, addr);
    }
    }

#ifdef PUSH_ARGS_REVERSED
#ifdef STACK_BOUNDARY
  /* If we push args individually in reverse order, perform stack alignment
     before the first push (the last arg).  */
  if (argblock == 0)
    anti_adjust_stack (GEN_INT (args_size.constant
                - original_args_size.constant));
#endif
#endif

  /* Don't try to defer pops if preallocating, not even from the first arg,
     since ARGBLOCK probably refers to the SP.  */
  if (argblock)
    NO_DEFER_POP;

  /* Get the function to call, in the form of RTL.  */
  if (fndecl)
    {
      /* If this is the first use of the function, see if we need to
     make an external definition for it.  */
      if (! TREE_USED (fndecl))
    {
      assemble_external (fndecl);
      TREE_USED (fndecl) = 1;
    }

      /* Get a SYMBOL_REF rtx for the function address.  */
      funexp = XEXP (DECL_RTL (fndecl), 0);
    }
  else
    /* Generate an rtx (probably a pseudo-register) for the address.  */
    {
      push_temp_slots ();
      funexp = expand_expr (TREE_OPERAND (exp, 0), NULL_RTX, VOIDmode, 0);
      pop_temp_slots ();    /* FUNEXP can't be BLKmode */
      emit_queue ();
    }

  /* Figure out the register where the value, if any, will come back.  */
  valreg = 0;
  if (TYPE_MODE (TREE_TYPE (exp)) != VOIDmode
      && ! structure_value_addr)
    {
      if (pcc_struct_value)
    valreg = hard_function_value (build_pointer_type (TREE_TYPE (exp)),
                      fndecl);
      else
    valreg = hard_function_value (TREE_TYPE (exp), fndecl);
    }

  /* Precompute all register parameters.  It isn't safe to compute anything
     once we have started filling any specific hard regs. */
  reg_parm_seen = 0;
  for (i = 0; i < num_actuals; i++)
    if (args[i].reg != 0 && ! args[i].pass_on_stack)
      {
    reg_parm_seen = 1;

    if (args[i].value == 0)
      {
        push_temp_slots ();
        args[i].value = expand_expr (args[i].tree_value, NULL_RTX,
                     VOIDmode, 0);
        preserve_temp_slots (args[i].value);
        pop_temp_slots ();

        /* ANSI doesn't require a sequence point here,
           but PCC has one, so this will avoid some problems.  */
        emit_queue ();
      }

    /* If we are to promote the function arg to a wider mode,
       do it now.  */

    if (args[i].mode != TYPE_MODE (TREE_TYPE (args[i].tree_value)))
      args[i].value
        = convert_modes (args[i].mode,
                 TYPE_MODE (TREE_TYPE (args[i].tree_value)),
                 args[i].value, args[i].unsignedp);

    /* If the value is expensive, and we are inside an appropriately
       short loop, put the value into a pseudo and then put the pseudo
       into the hard reg.

       For small register classes, also do this if this call uses
       register parameters.  This is to avoid reload conflicts while
       loading the parameters registers.  */

    if ((! (GET_CODE (args[i].value) == REG
        || (GET_CODE (args[i].value) == SUBREG
            && GET_CODE (SUBREG_REG (args[i].value)) == REG)))
        && args[i].mode != BLKmode
        && rtx_cost (args[i].value, SET) > 2
#ifdef SMALL_REGISTER_CLASSES
        && (reg_parm_seen || preserve_subexpressions_p ())
#else
        && preserve_subexpressions_p ()
#endif
        )
      args[i].value = copy_to_mode_reg (args[i].mode, args[i].value);
      }

#if defined(ACCUMULATE_OUTGOING_ARGS) && defined(REG_PARM_STACK_SPACE)
  /* The argument list is the property of the called routine and it
     may clobber it.  If the fixed area has been used for previous
     parameters, we must save and restore it.

     Here we compute the boundary of the that needs to be saved, if any.  */

#ifdef ARGS_GROW_DOWNWARD
  for (i = 0; i < reg_parm_stack_space + 1; i++)
#else
  for (i = 0; i < reg_parm_stack_space; i++)
#endif
    {
      if (i >=  highest_outgoing_arg_in_use
      || stack_usage_map[i] == 0)
    continue;

      if (low_to_save == -1)
    low_to_save = i;

      high_to_save = i;
    }

  if (low_to_save >= 0)
    {
      int num_to_save = high_to_save - low_to_save + 1;
      enum machine_mode save_mode
    = mode_for_size (num_to_save * BITS_PER_UNIT, MODE_INT, 1);
      rtx stack_area;

      /* If we don't have the required alignment, must do this in BLKmode.  */
      if ((low_to_save & (MIN (GET_MODE_SIZE (save_mode),
                   BIGGEST_ALIGNMENT / UNITS_PER_WORD) - 1)))
    save_mode = BLKmode;

      stack_area = gen_rtx (MEM, save_mode,
                memory_address (save_mode,

#ifdef ARGS_GROW_DOWNWARD
                        plus_constant (argblock,
                               - high_to_save)
#else
                        plus_constant (argblock,
                               low_to_save)
#endif
                        ));
      if (save_mode == BLKmode)
    {
      save_area = assign_stack_temp (BLKmode, num_to_save, 1);
      emit_block_move (validize_mem (save_area), stack_area,
               GEN_INT (num_to_save),
               PARM_BOUNDARY / BITS_PER_UNIT);
    }
      else
    {
      save_area = gen_reg_rtx (save_mode);
      emit_move_insn (save_area, stack_area);
    }
    }
#endif


  /* Now store (and compute if necessary) all non-register parms.
     These come before register parms, since they can require block-moves,
     which could clobber the registers used for register parms.
     Parms which have partial registers are not stored here,
     but we do preallocate space here if they want that.  */

  for (i = 0; i < num_actuals; i++)
    if (args[i].reg == 0 || args[i].pass_on_stack)
      store_one_arg (&args[i], argblock, may_be_alloca,
             args_size.var != 0, fndecl, reg_parm_stack_space);

#ifdef STRICT_ALIGNMENT
  /* If we have a parm that is passed in registers but not in memory
     and whose alignment does not permit a direct copy into registers,
     make a group of pseudos that correspond to each register that we
     will later fill.  */

  for (i = 0; i < num_actuals; i++)
    if (args[i].reg != 0 && ! args[i].pass_on_stack
    && args[i].mode == BLKmode
    && (TYPE_ALIGN (TREE_TYPE (args[i].tree_value))
        < MIN (BIGGEST_ALIGNMENT, BITS_PER_WORD)))
      {
    int bytes = int_size_in_bytes (TREE_TYPE (args[i].tree_value));
    int big_endian_correction = 0;

    args[i].n_aligned_regs
      = args[i].partial ? args[i].partial
        : (bytes + (UNITS_PER_WORD - 1)) / UNITS_PER_WORD;

    args[i].aligned_regs = (rtx *) alloca (sizeof (rtx)
                           * args[i].n_aligned_regs);

    /* Structures smaller than a word are aligned to the least signifcant
       byte (to the right).  On a BYTES_BIG_ENDIAN machine, this means we
       must skip the empty high order bytes when calculating the bit
       offset.  */
    if (BYTES_BIG_ENDIAN && bytes < UNITS_PER_WORD)
      big_endian_correction = (BITS_PER_WORD  - (bytes * BITS_PER_UNIT));

    for (j = 0; j < args[i].n_aligned_regs; j++)
      {
        rtx reg = gen_reg_rtx (word_mode);
        rtx word = operand_subword_force (args[i].value, j, BLKmode);
        int bitsize = TYPE_ALIGN (TREE_TYPE (args[i].tree_value));
        int bitpos;

        args[i].aligned_regs[j] = reg;

        /* Clobber REG and move each partword into it.  Ensure we don't
           go past the end of the structure.  Note that the loop below
           works because we've already verified that padding
           and endianness are compatible.  */

        emit_insn (gen_rtx (CLOBBER, VOIDmode, reg));

        for (bitpos = 0;
         bitpos < BITS_PER_WORD && bytes > 0;
         bitpos += bitsize, bytes -= bitsize / BITS_PER_UNIT)
          {
        int xbitpos = bitpos + big_endian_correction;

        store_bit_field (reg, bitsize, xbitpos, word_mode,
                 extract_bit_field (word, bitsize, bitpos, 1,
                            NULL_RTX, word_mode,
                            word_mode,
                            bitsize / BITS_PER_UNIT,
                            BITS_PER_WORD),
                 bitsize / BITS_PER_UNIT, BITS_PER_WORD);
          }
      }
      }
#endif

  /* Now store any partially-in-registers parm.
     This is the last place a block-move can happen.  */
  if (reg_parm_seen)
    for (i = 0; i < num_actuals; i++)
      if (args[i].partial != 0 && ! args[i].pass_on_stack)
    store_one_arg (&args[i], argblock, may_be_alloca,
               args_size.var != 0, fndecl, reg_parm_stack_space);

#ifndef PUSH_ARGS_REVERSED
#ifdef STACK_BOUNDARY
  /* If we pushed args in forward order, perform stack alignment
     after pushing the last arg.  */
  if (argblock == 0)
    anti_adjust_stack (GEN_INT (args_size.constant
                - original_args_size.constant));
#endif
#endif

  /* If register arguments require space on the stack and stack space
     was not preallocated, allocate stack space here for arguments
     passed in registers.  */
#if ! defined(ACCUMULATE_OUTGOING_ARGS) && defined(OUTGOING_REG_PARM_STACK_SPACE)
  if (must_preallocate == 0 && reg_parm_stack_space > 0)
    anti_adjust_stack (GEN_INT (reg_parm_stack_space));
#endif

  /* Pass the function the address in which to return a structure value.  */
  if (structure_value_addr && ! structure_value_addr_parm)
    {
      emit_move_insn (struct_value_rtx,
              force_reg (Pmode,
                 force_operand (structure_value_addr,
                        NULL_RTX)));
      if (GET_CODE (struct_value_rtx) == REG)
      use_reg (&call_fusage, struct_value_rtx);
    }

  funexp = prepare_call_address (funexp, fndecl, &call_fusage, reg_parm_seen);

  /* Now do the register loads required for any wholly-register parms or any
     parms which are passed both on the stack and in a register.  Their
     expressions were already evaluated.

     Mark all register-parms as living through the call, putting these USE
     insns in the CALL_INSN_FUNCTION_USAGE field.  */

  for (i = 0; i < num_actuals; i++)
    {
      rtx list = args[i].reg;
      int partial = args[i].partial;

      while (list)
    {
      rtx reg;
      int nregs;

      /* Process each register that needs to get this arg.  */
      if (GET_CODE (list) == EXPR_LIST)
        reg = XEXP (list, 0), list = XEXP (list, 1);
      else
        reg = list, list = 0;

      /* Set to non-negative if must move a word at a time, even if just
         one word (e.g, partial == 1 && mode == DFmode).  Set to -1 if
         we just use a normal move insn.  This value can be zero if the
         argument is a zero size structure with no fields.  */
      nregs = (partial ? partial
           : (TYPE_MODE (TREE_TYPE (args[i].tree_value)) == BLKmode
              ? ((int_size_in_bytes (TREE_TYPE (args[i].tree_value))
              + (UNITS_PER_WORD - 1)) / UNITS_PER_WORD)
              : -1));

      /* If simple case, just do move.  If normal partial, store_one_arg
         has already loaded the register for us.  In all other cases,
         load the register(s) from memory.  */

      if (nregs == -1)
        emit_move_insn (reg, args[i].value);

#ifdef STRICT_ALIGNMENT
      /* If we have pre-computed the values to put in the registers in
         the case of non-aligned structures, copy them in now.  */

      else if (args[i].n_aligned_regs != 0)
        for (j = 0; j < args[i].n_aligned_regs; j++)
          emit_move_insn (gen_rtx (REG, word_mode, REGNO (reg) + j),
                  args[i].aligned_regs[j]);
#endif

      else if (args[i].partial == 0 || args[i].pass_on_stack)
        move_block_to_reg (REGNO (reg),
                   validize_mem (args[i].value), nregs,
                   args[i].mode);

      if (nregs == -1)
        use_reg (&call_fusage, reg);
      else
        use_regs (&call_fusage, REGNO (reg), nregs == 0 ? 1 : nregs);

      /* PARTIAL referred only to the first register, so clear it for the
         next time.  */
      partial = 0;
    }
    }

  /* Perform postincrements before actually calling the function.  */
  emit_queue ();

  /* All arguments and registers used for the call must be set up by now!  */

  /* Generate the actual call instruction.  */
  emit_call_1 (funexp, funtype, args_size.constant, struct_value_size,
           FUNCTION_ARG (args_so_far, VOIDmode, void_type_node, 1),
           valreg, old_inhibit_defer_pop, call_fusage, is_const);

  /* If call is cse'able, make appropriate pair of reg-notes around it.
     Test valreg so we don't crash; may safely ignore `const'
     if return type is void.  */
  if (is_const && valreg != 0)
    {
      rtx note = 0;
      rtx temp = gen_reg_rtx (GET_MODE (valreg));
      rtx insns;

      /* Construct an "equal form" for the value which mentions all the
     arguments in order as well as the function name.  */
#ifdef PUSH_ARGS_REVERSED
      for (i = 0; i < num_actuals; i++)
    note = gen_rtx (EXPR_LIST, VOIDmode, args[i].initial_value, note);
#else
      for (i = num_actuals - 1; i >= 0; i--)
    note = gen_rtx (EXPR_LIST, VOIDmode, args[i].initial_value, note);
#endif
      note = gen_rtx (EXPR_LIST, VOIDmode, funexp, note);

      insns = get_insns ();
      end_sequence ();

      emit_libcall_block (insns, temp, valreg, note);

      valreg = temp;
    }
  else if (is_const)
    {
      /* Otherwise, just write out the sequence without a note.  */
      rtx insns = get_insns ();

      end_sequence ();
      emit_insns (insns);
    }

  /* For calls to `setjmp', etc., inform flow.c it should complain
     if nonvolatile values are live.  */

  if (returns_twice)
    {
      emit_note (name, NOTE_INSN_SETJMP);
      current_function_calls_setjmp = 1;
    }

  if (is_longjmp)
    current_function_calls_longjmp = 1;

  /* Notice functions that cannot return.
     If optimizing, insns emitted below will be dead.
     If not optimizing, they will exist, which is useful
     if the user uses the `return' command in the debugger.  */

  if (is_volatile || is_longjmp)
    emit_barrier ();

  /* If value type not void, return an rtx for the value.  */

  /* If there are cleanups to be called, don't use a hard reg as target.  */
  if (cleanups_this_call != old_cleanups
      && target && REG_P (target)
      && REGNO (target) < FIRST_PSEUDO_REGISTER)
    target = 0;

  if (TYPE_MODE (TREE_TYPE (exp)) == VOIDmode
      || ignore)
    {
      target = const0_rtx;
    }
  else if (structure_value_addr)
    {
      if (target == 0 || GET_CODE (target) != MEM)
    {
      target = gen_rtx (MEM, TYPE_MODE (TREE_TYPE (exp)),
                memory_address (TYPE_MODE (TREE_TYPE (exp)),
                        structure_value_addr));
      MEM_IN_STRUCT_P (target) = AGGREGATE_TYPE_P (TREE_TYPE (exp));
    }
    }
  else if (pcc_struct_value)
    {
      if (target == 0)
    {
      /* We used leave the value in the location that it is
         returned in, but that causes problems if it is used more
         than once in one expression.  Rather than trying to track
         when a copy is required, we always copy when TARGET is
         not specified.  This calling sequence is only used on
         a few machines and TARGET is usually nonzero.  */
      if (TYPE_MODE (TREE_TYPE (exp)) == BLKmode)
        {
          target = assign_stack_temp (BLKmode,
                      int_size_in_bytes (TREE_TYPE (exp)),
                      0);

          MEM_IN_STRUCT_P (target) = AGGREGATE_TYPE_P (TREE_TYPE (exp));

          /* Save this temp slot around the pop below.  */
          preserve_temp_slots (target);
        }
      else
        target = gen_reg_rtx (TYPE_MODE (TREE_TYPE (exp)));
    }

      if (TYPE_MODE (TREE_TYPE (exp)) != BLKmode)
    emit_move_insn (target, gen_rtx (MEM, TYPE_MODE (TREE_TYPE (exp)),
                     copy_to_reg (valreg)));
      else
    emit_block_move (target, gen_rtx (MEM, BLKmode, copy_to_reg (valreg)),
             expr_size (exp),
             TYPE_ALIGN (TREE_TYPE (exp)) / BITS_PER_UNIT);
    }
  else if (target && GET_MODE (target) == TYPE_MODE (TREE_TYPE (exp))
       && GET_MODE (target) == GET_MODE (valreg))
    /* TARGET and VALREG cannot be equal at this point because the latter
       would not have REG_FUNCTION_VALUE_P true, while the former would if
       it were referring to the same register.

       If they refer to the same register, this move will be a no-op, except
       when function inlining is being done.  */
    emit_move_insn (target, valreg);
  else
    target = copy_to_reg (valreg);

#ifdef PROMOTE_FUNCTION_RETURN
  /* If we promoted this return value, make the proper SUBREG.  TARGET
     might be const0_rtx here, so be careful.  */
  if (GET_CODE (target) == REG
      && GET_MODE (target) != TYPE_MODE (TREE_TYPE (exp)))
    {
      tree type = TREE_TYPE (exp);
      int unsignedp = TREE_UNSIGNED (type);

      /* If we don't promote as expected, something is wrong.  */
      if (GET_MODE (target)
      != promote_mode (type, TYPE_MODE (type), &unsignedp, 1))
    abort ();

      target = gen_rtx (SUBREG, TYPE_MODE (type), target, 0);
      SUBREG_PROMOTED_VAR_P (target) = 1;
      SUBREG_PROMOTED_UNSIGNED_P (target) = unsignedp;
    }
#endif

  if (flag_short_temps)
    {
      /* Perform all cleanups needed for the arguments of this call
     (i.e. destructors in C++).  */
      expand_cleanups_to (old_cleanups);
    }

  /* If size of args is variable or this was a constructor call for a stack
     argument, restore saved stack-pointer value.  */

  if (old_stack_level)
    {
      emit_stack_restore (SAVE_BLOCK, old_stack_level, NULL_RTX);
      pending_stack_adjust = old_pending_adj;
#ifdef ACCUMULATE_OUTGOING_ARGS
      stack_arg_under_construction = old_stack_arg_under_construction;
      highest_outgoing_arg_in_use = initial_highest_arg_in_use;
      stack_usage_map = initial_stack_usage_map;
#endif
    }
#ifdef ACCUMULATE_OUTGOING_ARGS
  else
    {
#ifdef REG_PARM_STACK_SPACE
      if (save_area)
    {
      enum machine_mode save_mode = GET_MODE (save_area);
      rtx stack_area
        = gen_rtx (MEM, save_mode,
               memory_address (save_mode,
#ifdef ARGS_GROW_DOWNWARD
                       plus_constant (argblock, - high_to_save)
#else
                       plus_constant (argblock, low_to_save)
#endif
                       ));

      if (save_mode != BLKmode)
        emit_move_insn (stack_area, save_area);
      else
        emit_block_move (stack_area, validize_mem (save_area),
                 GEN_INT (high_to_save - low_to_save + 1),
                 PARM_BOUNDARY / BITS_PER_UNIT);
    }
#endif

      /* If we saved any argument areas, restore them.  */
      for (i = 0; i < num_actuals; i++)
    if (args[i].save_area)
      {
        enum machine_mode save_mode = GET_MODE (args[i].save_area);
        rtx stack_area
          = gen_rtx (MEM, save_mode,
             memory_address (save_mode,
                     XEXP (args[i].stack_slot, 0)));

        if (save_mode != BLKmode)
          emit_move_insn (stack_area, args[i].save_area);
        else
          emit_block_move (stack_area, validize_mem (args[i].save_area),
                   GEN_INT (args[i].size.constant),
                   PARM_BOUNDARY / BITS_PER_UNIT);
      }

      highest_outgoing_arg_in_use = initial_highest_arg_in_use;
      stack_usage_map = initial_stack_usage_map;
    }
#endif

  /* If this was alloca, record the new stack level for nonlocal gotos.
     Check for the handler slots since we might not have a save area
     for non-local gotos. */

  if (may_be_alloca && nonlocal_goto_handler_slot != 0)
    emit_stack_save (SAVE_NONLOCAL, &nonlocal_goto_stack_level, NULL_RTX);

  pop_temp_slots ();

  return target;
}

/* Output a library call to function FUN (a SYMBOL_REF rtx)
   (emitting the queue unless NO_QUEUE is nonzero),
   for a value of mode OUTMODE,
   with NARGS different arguments, passed as alternating rtx values
   and machine_modes to convert them to.
   The rtx values should have been passed through protect_from_queue already.

   NO_QUEUE will be true if and only if the library call is a `const' call
   which will be enclosed in REG_LIBCALL/REG_RETVAL notes; it is equivalent
   to the variable is_const in expand_call.

   NO_QUEUE must be true for const calls, because if it isn't, then
   any pending increment will be emitted between REG_LIBCALL/REG_RETVAL notes,
   and will be lost if the libcall sequence is optimized away.

   NO_QUEUE must be false for non-const calls, because if it isn't, the
   call insn will have its CONST_CALL_P bit set, and it will be incorrectly
   optimized.  For instance, the instruction scheduler may incorrectly
   move memory references across the non-const call.  */

void
emit_library_call VPROTO((rtx orgfun, int no_queue, enum machine_mode outmode,
              int nargs, ...))
{
#ifndef __STDC__
  rtx orgfun;
  int no_queue;
  enum machine_mode outmode;
  int nargs;
#endif
  va_list p;
  /* Total size in bytes of all the stack-parms scanned so far.  */
  struct args_size args_size;
  /* Size of arguments before any adjustments (such as rounding).  */
  struct args_size original_args_size;
  register int argnum;
  rtx fun;
  int inc;
  int count;
  rtx argblock = 0;
  CUMULATIVE_ARGS args_so_far;
  struct arg { rtx value; enum machine_mode mode; rtx reg; int partial;
           struct args_size offset; struct args_size size; };
  struct arg *argvec;
  int old_inhibit_defer_pop = inhibit_defer_pop;
  rtx call_fusage = 0;
  /* library calls are never indirect calls.  */
  int current_call_is_indirect = 0;

  VA_START (p, nargs);

#ifndef __STDC__
  orgfun = va_arg (p, rtx);
  no_queue = va_arg (p, int);
  outmode = va_arg (p, enum machine_mode);
  nargs = va_arg (p, int);
#endif

  fun = orgfun;

  /* Copy all the libcall-arguments out of the varargs data
     and into a vector ARGVEC.

     Compute how to pass each argument.  We only support a very small subset
     of the full argument passing conventions to limit complexity here since
     library functions shouldn't have many args.  */

  argvec = (struct arg *) alloca (nargs * sizeof (struct arg));

  INIT_CUMULATIVE_ARGS (args_so_far, NULL_TREE, fun);

  args_size.constant = 0;
  args_size.var = 0;

  push_temp_slots ();

  for (count = 0; count < nargs; count++)
    {
      rtx val = va_arg (p, rtx);
      enum machine_mode mode = va_arg (p, enum machine_mode);

      /* We cannot convert the arg value to the mode the library wants here;
     must do it earlier where we know the signedness of the arg.  */
      if (mode == BLKmode
      || (GET_MODE (val) != mode && GET_MODE (val) != VOIDmode))
    abort ();

      /* On some machines, there's no way to pass a float to a library fcn.
     Pass it as a double instead.  */
#ifdef LIBGCC_NEEDS_DOUBLE
      if (LIBGCC_NEEDS_DOUBLE && mode == SFmode)
    val = convert_modes (DFmode, SFmode, val, 0), mode = DFmode;
#endif

      /* There's no need to call protect_from_queue, because
     either emit_move_insn or emit_push_insn will do that.  */

      /* Make sure it is a reasonable operand for a move or push insn.  */
      if (GET_CODE (val) != REG && GET_CODE (val) != MEM
      && ! (CONSTANT_P (val) && LEGITIMATE_CONSTANT_P (val)))
    val = force_operand (val, NULL_RTX);

#ifdef FUNCTION_ARG_PASS_BY_REFERENCE
      if (FUNCTION_ARG_PASS_BY_REFERENCE (args_so_far, mode, NULL_TREE, 1))
    {
      /* We do not support FUNCTION_ARG_CALLEE_COPIES here since it can
         be viewed as just an efficiency improvement.  */
      rtx slot = assign_stack_temp (mode, GET_MODE_SIZE (mode), 0);
      emit_move_insn (slot, val);
      val = force_operand (XEXP (slot, 0), NULL_RTX);
      mode = Pmode;
    }
#endif

      argvec[count].value = val;
      argvec[count].mode = mode;

      argvec[count].reg = FUNCTION_ARG (args_so_far, mode, NULL_TREE, 1);
      if (argvec[count].reg && GET_CODE (argvec[count].reg) == EXPR_LIST)
    abort ();
#ifdef FUNCTION_ARG_PARTIAL_NREGS
      argvec[count].partial
    = FUNCTION_ARG_PARTIAL_NREGS (args_so_far, mode, NULL_TREE, 1);
#else
      argvec[count].partial = 0;
#endif

      locate_and_pad_parm (mode, NULL_TREE,
               argvec[count].reg && argvec[count].partial == 0,
               NULL_TREE, &args_size, &argvec[count].offset,
               &argvec[count].size);

      if (argvec[count].size.var)
    abort ();

#ifndef REG_PARM_STACK_SPACE
      if (argvec[count].partial)
    argvec[count].size.constant -= argvec[count].partial * UNITS_PER_WORD;
#endif

      if (argvec[count].reg == 0 || argvec[count].partial != 0
#ifdef REG_PARM_STACK_SPACE
      || 1
#endif
      )
    args_size.constant += argvec[count].size.constant;

#ifdef ACCUMULATE_OUTGOING_ARGS
      /* If this arg is actually passed on the stack, it might be
     clobbering something we already put there (this library call might
     be inside the evaluation of an argument to a function whose call
     requires the stack).  This will only occur when the library call
     has sufficient args to run out of argument registers.  Abort in
     this case; if this ever occurs, code must be added to save and
     restore the arg slot.  */

      if (argvec[count].reg == 0 || argvec[count].partial != 0)
    abort ();
#endif

      FUNCTION_ARG_ADVANCE (args_so_far, mode, (tree)0, 1);
    }
  va_end (p);

  /* If this machine requires an external definition for library
     functions, write one out.  */
  assemble_external_libcall (fun);

  original_args_size = args_size;
#ifdef STACK_BOUNDARY
  args_size.constant = (((args_size.constant + (STACK_BYTES - 1))
             / STACK_BYTES) * STACK_BYTES);
#endif

#ifdef REG_PARM_STACK_SPACE
  args_size.constant = MAX (args_size.constant,
                REG_PARM_STACK_SPACE (NULL_TREE));
#ifndef OUTGOING_REG_PARM_STACK_SPACE
  args_size.constant -= REG_PARM_STACK_SPACE (NULL_TREE);
#endif
#endif

  if (args_size.constant > current_function_outgoing_args_size)
    current_function_outgoing_args_size = args_size.constant;

#ifdef ACCUMULATE_OUTGOING_ARGS
  args_size.constant = 0;
#endif

#ifndef PUSH_ROUNDING
  argblock = push_block (GEN_INT (args_size.constant), 0, 0);
#endif

#ifdef PUSH_ARGS_REVERSED
#ifdef STACK_BOUNDARY
  /* If we push args individually in reverse order, perform stack alignment
     before the first push (the last arg).  */
  if (argblock == 0)
    anti_adjust_stack (GEN_INT (args_size.constant
                - original_args_size.constant));
#endif
#endif

#ifdef PUSH_ARGS_REVERSED
  inc = -1;
  argnum = nargs - 1;
#else
  inc = 1;
  argnum = 0;
#endif

  /* Push the args that need to be pushed.  */

  for (count = 0; count < nargs; count++, argnum += inc)
    {
      register enum machine_mode mode = argvec[argnum].mode;
      register rtx val = argvec[argnum].value;
      rtx reg = argvec[argnum].reg;
      int partial = argvec[argnum].partial;

      if (! (reg != 0 && partial == 0))
    emit_push_insn (val, mode, NULL_TREE, NULL_RTX, 0, partial, reg, 0,
            argblock, GEN_INT (argvec[count].offset.constant));
      NO_DEFER_POP;
    }

#ifndef PUSH_ARGS_REVERSED
#ifdef STACK_BOUNDARY
  /* If we pushed args in forward order, perform stack alignment
     after pushing the last arg.  */
  if (argblock == 0)
    anti_adjust_stack (GEN_INT (args_size.constant
                - original_args_size.constant));
#endif
#endif

#ifdef PUSH_ARGS_REVERSED
  argnum = nargs - 1;
#else
  argnum = 0;
#endif

  fun = prepare_call_address (fun, NULL_TREE, &call_fusage, 0);

  /* Now load any reg parms into their regs.  */

  for (count = 0; count < nargs; count++, argnum += inc)
    {
      register enum machine_mode mode = argvec[argnum].mode;
      register rtx val = argvec[argnum].value;
      rtx reg = argvec[argnum].reg;
      int partial = argvec[argnum].partial;

      if (reg != 0 && partial == 0)
    emit_move_insn (reg, val);
      NO_DEFER_POP;
    }

  /* For version 1.37, try deleting this entirely.  */
  if (! no_queue)
    emit_queue ();

  /* Any regs containing parms remain in use through the call.  */
  for (count = 0; count < nargs; count++)
    if (argvec[count].reg != 0)
       use_reg (&call_fusage, argvec[count].reg);

  /* Don't allow popping to be deferred, since then
     cse'ing of library calls could delete a call and leave the pop.  */
  NO_DEFER_POP;

  /* We pass the old value of inhibit_defer_pop + 1 to emit_call_1, which
     will set inhibit_defer_pop to that value.  */

  emit_call_1 (fun, get_identifier (XSTR (orgfun, 0)), args_size.constant, 0,
           FUNCTION_ARG (args_so_far, VOIDmode, void_type_node, 1),
           outmode != VOIDmode ? hard_libcall_value (outmode) : NULL_RTX,
           old_inhibit_defer_pop + 1, call_fusage, no_queue);

  pop_temp_slots ();

  /* Now restore inhibit_defer_pop to its actual original value.  */
  OK_DEFER_POP;
}

/* Like emit_library_call except that an extra argument, VALUE,
   comes second and says where to store the result.
   (If VALUE is zero, this function chooses a convenient way
   to return the value.

   This function returns an rtx for where the value is to be found.
   If VALUE is nonzero, VALUE is returned.  */

rtx
emit_library_call_value VPROTO((rtx orgfun, rtx value, int no_queue,
                enum machine_mode outmode, int nargs, ...))
{
#ifndef __STDC__
  rtx orgfun;
  rtx value;
  int no_queue;
  enum machine_mode outmode;
  int nargs;
#endif
  va_list p;
  /* Total size in bytes of all the stack-parms scanned so far.  */
  struct args_size args_size;
  /* Size of arguments before any adjustments (such as rounding).  */
  struct args_size original_args_size;
  register int argnum;
  rtx fun;
  int inc;
  int count;
  rtx argblock = 0;
  CUMULATIVE_ARGS args_so_far;
  struct arg { rtx value; enum machine_mode mode; rtx reg; int partial;
           struct args_size offset; struct args_size size; };
  struct arg *argvec;
  int old_inhibit_defer_pop = inhibit_defer_pop;
  rtx call_fusage = 0;
  rtx mem_value = 0;
  int pcc_struct_value = 0;
  int struct_value_size = 0;
  /* library calls are never indirect calls.  */
  int current_call_is_indirect = 0;
  int is_const;

  VA_START (p, nargs);

#ifndef __STDC__
  orgfun = va_arg (p, rtx);
  value = va_arg (p, rtx);
  no_queue = va_arg (p, int);
  outmode = va_arg (p, enum machine_mode);
  nargs = va_arg (p, int);
#endif

  is_const = no_queue;
  fun = orgfun;

  /* If this kind of value comes back in memory,
     decide where in memory it should come back.  */
  if (aggregate_value_p (type_for_mode (outmode, 0)))
    {
#ifdef PCC_STATIC_STRUCT_RETURN
      rtx pointer_reg
    = hard_function_value (build_pointer_type (type_for_mode (outmode, 0)),
                   0);
      mem_value = gen_rtx (MEM, outmode, pointer_reg);
      pcc_struct_value = 1;
      if (value == 0)
    value = gen_reg_rtx (outmode);
#else /* not PCC_STATIC_STRUCT_RETURN */
      struct_value_size = GET_MODE_SIZE (outmode);
      if (value != 0 && GET_CODE (value) == MEM)
    mem_value = value;
      else
    mem_value = assign_stack_temp (outmode, GET_MODE_SIZE (outmode), 0);
#endif

      /* This call returns a big structure.  */
      is_const = 0;
    }

  /* ??? Unfinished: must pass the memory address as an argument.  */

  /* Copy all the libcall-arguments out of the varargs data
     and into a vector ARGVEC.

     Compute how to pass each argument.  We only support a very small subset
     of the full argument passing conventions to limit complexity here since
     library functions shouldn't have many args.  */

  argvec = (struct arg *) alloca ((nargs + 1) * sizeof (struct arg));

  INIT_CUMULATIVE_ARGS (args_so_far, NULL_TREE, fun);

  args_size.constant = 0;
  args_size.var = 0;

  count = 0;

  push_temp_slots ();

  /* If there's a structure value address to be passed,
     either pass it in the special place, or pass it as an extra argument.  */
  if (mem_value && struct_value_rtx == 0 && ! pcc_struct_value)
    {
      rtx addr = XEXP (mem_value, 0);
      nargs++;

      /* Make sure it is a reasonable operand for a move or push insn.  */
      if (GET_CODE (addr) != REG && GET_CODE (addr) != MEM
      && ! (CONSTANT_P (addr) && LEGITIMATE_CONSTANT_P (addr)))
    addr = force_operand (addr, NULL_RTX);

      argvec[count].value = addr;
      argvec[count].mode = Pmode;
      argvec[count].partial = 0;

      argvec[count].reg = FUNCTION_ARG (args_so_far, Pmode, NULL_TREE, 1);
#ifdef FUNCTION_ARG_PARTIAL_NREGS
      if (FUNCTION_ARG_PARTIAL_NREGS (args_so_far, Pmode, NULL_TREE, 1))
    abort ();
#endif

      locate_and_pad_parm (Pmode, NULL_TREE,
               argvec[count].reg && argvec[count].partial == 0,
               NULL_TREE, &args_size, &argvec[count].offset,
               &argvec[count].size);


      if (argvec[count].reg == 0 || argvec[count].partial != 0
#ifdef REG_PARM_STACK_SPACE
      || 1
#endif
      )
    args_size.constant += argvec[count].size.constant;

      FUNCTION_ARG_ADVANCE (args_so_far, Pmode, (tree)0, 1);

      count++;
    }

  for (; count < nargs; count++)
    {
      rtx val = va_arg (p, rtx);
      enum machine_mode mode = va_arg (p, enum machine_mode);

      /* We cannot convert the arg value to the mode the library wants here;
     must do it earlier where we know the signedness of the arg.  */
      if (mode == BLKmode
      || (GET_MODE (val) != mode && GET_MODE (val) != VOIDmode))
    abort ();

      /* On some machines, there's no way to pass a float to a library fcn.
     Pass it as a double instead.  */
#ifdef LIBGCC_NEEDS_DOUBLE
      if (LIBGCC_NEEDS_DOUBLE && mode == SFmode)
    val = convert_modes (DFmode, SFmode, val, 0), mode = DFmode;
#endif

      /* There's no need to call protect_from_queue, because
     either emit_move_insn or emit_push_insn will do that.  */

      /* Make sure it is a reasonable operand for a move or push insn.  */
      if (GET_CODE (val) != REG && GET_CODE (val) != MEM
      && ! (CONSTANT_P (val) && LEGITIMATE_CONSTANT_P (val)))
    val = force_operand (val, NULL_RTX);

#ifdef FUNCTION_ARG_PASS_BY_REFERENCE
      if (FUNCTION_ARG_PASS_BY_REFERENCE (args_so_far, mode, NULL_TREE, 1))
    {
      /* We do not support FUNCTION_ARG_CALLEE_COPIES here since it can
         be viewed as just an efficiency improvement.  */
      rtx slot = assign_stack_temp (mode, GET_MODE_SIZE (mode), 0);
      emit_move_insn (slot, val);
      val = XEXP (slot, 0);
      mode = Pmode;
    }
#endif

      argvec[count].value = val;
      argvec[count].mode = mode;

      argvec[count].reg = FUNCTION_ARG (args_so_far, mode, NULL_TREE, 1);
      if (argvec[count].reg && GET_CODE (argvec[count].reg) == EXPR_LIST)
    abort ();
#ifdef FUNCTION_ARG_PARTIAL_NREGS
      argvec[count].partial
    = FUNCTION_ARG_PARTIAL_NREGS (args_so_far, mode, NULL_TREE, 1);
#else
      argvec[count].partial = 0;
#endif

      locate_and_pad_parm (mode, NULL_TREE,
               argvec[count].reg && argvec[count].partial == 0,
               NULL_TREE, &args_size, &argvec[count].offset,
               &argvec[count].size);

      if (argvec[count].size.var)
    abort ();

#ifndef REG_PARM_STACK_SPACE
      if (argvec[count].partial)
    argvec[count].size.constant -= argvec[count].partial * UNITS_PER_WORD;
#endif

      if (argvec[count].reg == 0 || argvec[count].partial != 0
#ifdef REG_PARM_STACK_SPACE
      || 1
#endif
      )
    args_size.constant += argvec[count].size.constant;

#ifdef ACCUMULATE_OUTGOING_ARGS
      /* If this arg is actually passed on the stack, it might be
     clobbering something we already put there (this library call might
     be inside the evaluation of an argument to a function whose call
     requires the stack).  This will only occur when the library call
     has sufficient args to run out of argument registers.  Abort in
     this case; if this ever occurs, code must be added to save and
     restore the arg slot.  */

      if (argvec[count].reg == 0 || argvec[count].partial != 0)
    abort ();
#endif

      FUNCTION_ARG_ADVANCE (args_so_far, mode, (tree)0, 1);
    }
  va_end (p);

  /* If this machine requires an external definition for library
     functions, write one out.  */
  assemble_external_libcall (fun);

  original_args_size = args_size;
#ifdef STACK_BOUNDARY
  args_size.constant = (((args_size.constant + (STACK_BYTES - 1))
             / STACK_BYTES) * STACK_BYTES);
#endif

#ifdef REG_PARM_STACK_SPACE
  args_size.constant = MAX (args_size.constant,
                REG_PARM_STACK_SPACE (NULL_TREE));
#ifndef OUTGOING_REG_PARM_STACK_SPACE
  args_size.constant -= REG_PARM_STACK_SPACE (NULL_TREE);
#endif
#endif

  if (args_size.constant > current_function_outgoing_args_size)
    current_function_outgoing_args_size = args_size.constant;

#ifdef ACCUMULATE_OUTGOING_ARGS
  args_size.constant = 0;
#endif

#ifndef PUSH_ROUNDING
  argblock = push_block (GEN_INT (args_size.constant), 0, 0);
#endif

#ifdef PUSH_ARGS_REVERSED
#ifdef STACK_BOUNDARY
  /* If we push args individually in reverse order, perform stack alignment
     before the first push (the last arg).  */
  if (argblock == 0)
    anti_adjust_stack (GEN_INT (args_size.constant
                - original_args_size.constant));
#endif
#endif

#ifdef PUSH_ARGS_REVERSED
  inc = -1;
  argnum = nargs - 1;
#else
  inc = 1;
  argnum = 0;
#endif

  /* Push the args that need to be pushed.  */

  for (count = 0; count < nargs; count++, argnum += inc)
    {
      register enum machine_mode mode = argvec[argnum].mode;
      register rtx val = argvec[argnum].value;
      rtx reg = argvec[argnum].reg;
      int partial = argvec[argnum].partial;

      if (! (reg != 0 && partial == 0))
    emit_push_insn (val, mode, NULL_TREE, NULL_RTX, 0, partial, reg, 0,
            argblock, GEN_INT (argvec[count].offset.constant));
      NO_DEFER_POP;
    }

#ifndef PUSH_ARGS_REVERSED
#ifdef STACK_BOUNDARY
  /* If we pushed args in forward order, perform stack alignment
     after pushing the last arg.  */
  if (argblock == 0)
    anti_adjust_stack (GEN_INT (args_size.constant
                - original_args_size.constant));
#endif
#endif

#ifdef PUSH_ARGS_REVERSED
  argnum = nargs - 1;
#else
  argnum = 0;
#endif

  fun = prepare_call_address (fun, NULL_TREE, &call_fusage, 0);

  /* Now load any reg parms into their regs.  */

  for (count = 0; count < nargs; count++, argnum += inc)
    {
      register enum machine_mode mode = argvec[argnum].mode;
      register rtx val = argvec[argnum].value;
      rtx reg = argvec[argnum].reg;
      int partial = argvec[argnum].partial;

      if (reg != 0 && partial == 0)
    emit_move_insn (reg, val);
      NO_DEFER_POP;
    }

#if 0
  /* For version 1.37, try deleting this entirely.  */
  if (! no_queue)
    emit_queue ();
#endif

  /* Any regs containing parms remain in use through the call.  */
  for (count = 0; count < nargs; count++)
    if (argvec[count].reg != 0)
       use_reg (&call_fusage, argvec[count].reg);

  /* Pass the function the address in which to return a structure value.  */
  if (mem_value != 0 && struct_value_rtx != 0 && ! pcc_struct_value)
    {
      emit_move_insn (struct_value_rtx,
              force_reg (Pmode,
                 force_operand (XEXP (mem_value, 0),
                        NULL_RTX)));
      if (GET_CODE (struct_value_rtx) == REG)
      use_reg (&call_fusage, struct_value_rtx);
    }

  /* Don't allow popping to be deferred, since then
     cse'ing of library calls could delete a call and leave the pop.  */
  NO_DEFER_POP;

  /* We pass the old value of inhibit_defer_pop + 1 to emit_call_1, which
     will set inhibit_defer_pop to that value.  */

  emit_call_1 (fun, get_identifier (XSTR (orgfun, 0)), args_size.constant,
           struct_value_size,
           FUNCTION_ARG (args_so_far, VOIDmode, void_type_node, 1),
           (outmode != VOIDmode && mem_value == 0
        ? hard_libcall_value (outmode) : NULL_RTX),
           old_inhibit_defer_pop + 1, call_fusage, is_const);

  /* Now restore inhibit_defer_pop to its actual original value.  */
  OK_DEFER_POP;

  pop_temp_slots ();

  /* Copy the value to the right place.  */
  if (outmode != VOIDmode)
    {
      if (mem_value)
    {
      if (value == 0)
        value = mem_value;
      if (value != mem_value)
        emit_move_insn (value, mem_value);
    }
      else if (value != 0)
    emit_move_insn (value, hard_libcall_value (outmode));
      else
    value = hard_libcall_value (outmode);
    }

  return value;
}

#if 0
/* Return an rtx which represents a suitable home on the stack
   given TYPE, the type of the argument looking for a home.
   This is called only for BLKmode arguments.

   SIZE is the size needed for this target.
   ARGS_ADDR is the address of the bottom of the argument block for this call.
   OFFSET describes this parameter's offset into ARGS_ADDR.  It is meaningless
   if this machine uses push insns.  */

static rtx
target_for_arg (type, size, args_addr, offset)
     tree type;
     rtx size;
     rtx args_addr;
     struct args_size offset;
{
  rtx target;
  rtx offset_rtx = ARGS_SIZE_RTX (offset);

  /* We do not call memory_address if possible,
     because we want to address as close to the stack
     as possible.  For non-variable sized arguments,
     this will be stack-pointer relative addressing.  */
  if (GET_CODE (offset_rtx) == CONST_INT)
    target = plus_constant (args_addr, INTVAL (offset_rtx));
  else
    {
      /* I have no idea how to guarantee that this
     will work in the presence of register parameters.  */
      target = gen_rtx (PLUS, Pmode, args_addr, offset_rtx);
      target = memory_address (QImode, target);
    }

  return gen_rtx (MEM, BLKmode, target);
}
#endif

/* Store a single argument for a function call
   into the register or memory area where it must be passed.
   *ARG describes the argument value and where to pass it.

   ARGBLOCK is the address of the stack-block for all the arguments,
   or 0 on a machine where arguments are pushed individually.

   MAY_BE_ALLOCA nonzero says this could be a call to `alloca'
   so must be careful about how the stack is used.

   VARIABLE_SIZE nonzero says that this was a variable-sized outgoing
   argument stack.  This is used if ACCUMULATE_OUTGOING_ARGS to indicate
   that we need not worry about saving and restoring the stack.

   FNDECL is the declaration of the function we are calling.  */

static void
store_one_arg (arg, argblock, may_be_alloca, variable_size, fndecl,
           reg_parm_stack_space)
     struct arg_data *arg;
     rtx argblock;
     int may_be_alloca;
     int variable_size;
     tree fndecl;
     int reg_parm_stack_space;
{
  register tree pval = arg->tree_value;
  rtx reg = 0;
  int partial = 0;
  int used = 0;
  int i, lower_bound, upper_bound;

  if (TREE_CODE (pval) == ERROR_MARK)
    return;

  /* Push a new temporary level for any temporaries we make for
     this argument.  */
  push_temp_slots ();

#ifdef ACCUMULATE_OUTGOING_ARGS
  /* If this is being stored into a pre-allocated, fixed-size, stack area,
     save any previous data at that location.  */
  if (argblock && ! variable_size && arg->stack)
    {
#ifdef ARGS_GROW_DOWNWARD
      /* stack_slot is negative, but we want to index stack_usage_map */
      /* with positive values. */
      if (GET_CODE (XEXP (arg->stack_slot, 0)) == PLUS)
    upper_bound = -INTVAL (XEXP (XEXP (arg->stack_slot, 0), 1)) + 1;
      else
    abort ();

      lower_bound = upper_bound - arg->size.constant;
#else
      if (GET_CODE (XEXP (arg->stack_slot, 0)) == PLUS)
    lower_bound = INTVAL (XEXP (XEXP (arg->stack_slot, 0), 1));
      else
    lower_bound = 0;

      upper_bound = lower_bound + arg->size.constant;
#endif

      for (i = lower_bound; i < upper_bound; i++)
    if (stack_usage_map[i]
#ifdef REG_PARM_STACK_SPACE
        /* Don't store things in the fixed argument area at this point;
           it has already been saved.  */
        && i > reg_parm_stack_space
#endif
        )
      break;

      if (i != upper_bound)
    {
      /* We need to make a save area.  See what mode we can make it.  */
      enum machine_mode save_mode
        = mode_for_size (arg->size.constant * BITS_PER_UNIT, MODE_INT, 1);
      rtx stack_area
        = gen_rtx (MEM, save_mode,
               memory_address (save_mode, XEXP (arg->stack_slot, 0)));

      if (save_mode == BLKmode)
        {
          arg->save_area = assign_stack_temp (BLKmode,
                          arg->size.constant, 1);
          preserve_temp_slots (arg->save_area);
          emit_block_move (validize_mem (arg->save_area), stack_area,
                   GEN_INT (arg->size.constant),
                   PARM_BOUNDARY / BITS_PER_UNIT);
        }
      else
        {
          arg->save_area = gen_reg_rtx (save_mode);
          emit_move_insn (arg->save_area, stack_area);
        }
    }
    }
#endif

  /* If this isn't going to be placed on both the stack and in registers,
     set up the register and number of words.  */
  if (! arg->pass_on_stack)
    reg = arg->reg, partial = arg->partial;

  if (reg != 0 && partial == 0)
    /* Being passed entirely in a register.  We shouldn't be called in
       this case.   */
    abort ();

#ifdef STRICT_ALIGNMENT
  /* If this arg needs special alignment, don't load the registers
     here.  */
  if (arg->n_aligned_regs != 0)
    reg = 0;
#endif

  /* If this is being partially passed in a register, but multiple locations
     are specified, we assume that the one partially used is the one that is
     listed first.  */
  if (reg && GET_CODE (reg) == EXPR_LIST)
    reg = XEXP (reg, 0);

  /* If this is being passed partially in a register, we can't evaluate
     it directly into its stack slot.  Otherwise, we can.  */
  if (arg->value == 0)
    {
#ifdef ACCUMULATE_OUTGOING_ARGS
      /* stack_arg_under_construction is nonzero if a function argument is
     being evaluated directly into the outgoing argument list and
     expand_call must take special action to preserve the argument list
     if it is called recursively.

     For scalar function arguments stack_usage_map is sufficient to
     determine which stack slots must be saved and restored.  Scalar
     arguments in general have pass_on_stack == 0.

     If this argument is initialized by a function which takes the
     address of the argument (a C++ constructor or a C function
     returning a BLKmode structure), then stack_usage_map is
     insufficient and expand_call must push the stack around the
     function call.  Such arguments have pass_on_stack == 1.

     Note that it is always safe to set stack_arg_under_construction,
     but this generates suboptimal code if set when not needed.  */

      if (arg->pass_on_stack)
    stack_arg_under_construction++;
#endif
      arg->value = expand_expr (pval,
                (partial
                 || TYPE_MODE (TREE_TYPE (pval)) != arg->mode)
                ? NULL_RTX : arg->stack,
                VOIDmode, 0);

      /* If we are promoting object (or for any other reason) the mode
     doesn't agree, convert the mode.  */

      if (arg->mode != TYPE_MODE (TREE_TYPE (pval)))
    arg->value = convert_modes (arg->mode, TYPE_MODE (TREE_TYPE (pval)),
                    arg->value, arg->unsignedp);

#ifdef ACCUMULATE_OUTGOING_ARGS
      if (arg->pass_on_stack)
    stack_arg_under_construction--;
#endif
    }

  /* Don't allow anything left on stack from computation
     of argument to alloca.  */
  if (may_be_alloca)
    do_pending_stack_adjust ();

  if (arg->value == arg->stack)
    /* If the value is already in the stack slot, we are done.  */
    ;
  else if (arg->mode != BLKmode)
    {
      register int size;

      /* Argument is a scalar, not entirely passed in registers.
     (If part is passed in registers, arg->partial says how much
     and emit_push_insn will take care of putting it there.)

     Push it, and if its size is less than the
     amount of space allocated to it,
     also bump stack pointer by the additional space.
     Note that in C the default argument promotions
     will prevent such mismatches.  */

      size = GET_MODE_SIZE (arg->mode);
      /* Compute how much space the push instruction will push.
     On many machines, pushing a byte will advance the stack
     pointer by a halfword.  */
#ifdef PUSH_ROUNDING
      size = PUSH_ROUNDING (size);
#endif
      used = size;

      /* Compute how much space the argument should get:
     round up to a multiple of the alignment for arguments.  */
      if (none != FUNCTION_ARG_PADDING (arg->mode, TREE_TYPE (pval)))
    used = (((size + PARM_BOUNDARY / BITS_PER_UNIT - 1)
         / (PARM_BOUNDARY / BITS_PER_UNIT))
        * (PARM_BOUNDARY / BITS_PER_UNIT));

      /* This isn't already where we want it on the stack, so put it there.
     This can either be done with push or copy insns.  */
      emit_push_insn (arg->value, arg->mode, TREE_TYPE (pval), NULL_RTX,
              0, partial, reg, used - size,
              argblock, ARGS_SIZE_RTX (arg->offset));
    }
  else
    {
      /* BLKmode, at least partly to be pushed.  */

      register int excess;
      rtx size_rtx;

      /* Pushing a nonscalar.
     If part is passed in registers, PARTIAL says how much
     and emit_push_insn will take care of putting it there.  */

      /* Round its size up to a multiple
     of the allocation unit for arguments.  */

      if (arg->size.var != 0)
    {
      excess = 0;
      size_rtx = ARGS_SIZE_RTX (arg->size);
    }
      else
    {
      /* PUSH_ROUNDING has no effect on us, because
         emit_push_insn for BLKmode is careful to avoid it.  */
      excess = (arg->size.constant - int_size_in_bytes (TREE_TYPE (pval))
            + partial * UNITS_PER_WORD);
      size_rtx = expr_size (pval);
    }

      emit_push_insn (arg->value, arg->mode, TREE_TYPE (pval), size_rtx,
              TYPE_ALIGN (TREE_TYPE (pval)) / BITS_PER_UNIT, partial,
              reg, excess, argblock, ARGS_SIZE_RTX (arg->offset));
    }


  /* Unless this is a partially-in-register argument, the argument is now
     in the stack.

     ??? Note that this can change arg->value from arg->stack to
     arg->stack_slot and it matters when they are not the same.
     It isn't totally clear that this is correct in all cases.  */
  if (partial == 0)
    arg->value = arg->stack_slot;

  /* Once we have pushed something, pops can't safely
     be deferred during the rest of the arguments.  */
  NO_DEFER_POP;

  /* ANSI doesn't require a sequence point here,
     but PCC has one, so this will avoid some problems.  */
  emit_queue ();

  /* Free any temporary slots made in processing this argument.  Show
     that we might have taken the address of something and pushed that
     as an operand.  */
  preserve_temp_slots (NULL_RTX);
  free_temp_slots ();
  pop_temp_slots ();

#ifdef ACCUMULATE_OUTGOING_ARGS
  /* Now mark the segment we just used.  */
  if (argblock && ! variable_size && arg->stack)
    for (i = lower_bound; i < upper_bound; i++)
      stack_usage_map[i] = 1;
#endif
}