Fix typos in comment

[official-gcc.git] / gcc / calls.c

/* Convert function calls to rtl insns, for GNU C compiler.
   Copyright (C) 1989, 1992, 1993, 1994, 1995, 1996, 1997, 1998
   1999, 2000 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, 59 Temple Place - Suite 330,
Boston, MA 02111-1307, USA.  */

#include "config.h"
#include "system.h"
#include "rtl.h"
#include "tree.h"
#include "flags.h"
#include "expr.h"
#include "function.h"
#include "regs.h"
#include "insn-flags.h"
#include "toplev.h"
#include "output.h"
#include "tm_p.h"
#include "timevar.h"
#include "sbitmap.h"

#ifndef ACCUMULATE_OUTGOING_ARGS
#define ACCUMULATE_OUTGOING_ARGS 0
#endif

/* Supply a default definition for PUSH_ARGS.  */
#ifndef PUSH_ARGS
#ifdef PUSH_ROUNDING
#define PUSH_ARGS       !ACCUMULATE_OUTGOING_ARGS
#else
#define PUSH_ARGS       0
#endif
#endif

#if !defined FUNCTION_OK_FOR_SIBCALL
#define FUNCTION_OK_FOR_SIBCALL(DECL) 1
#endif

#if !defined PREFERRED_STACK_BOUNDARY && defined STACK_BOUNDARY
#define PREFERRED_STACK_BOUNDARY STACK_BOUNDARY
#endif

/* 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  PUSH_ARGS
#endif

#endif

#ifndef PUSH_ARGS_REVERSED
#define PUSH_ARGS_REVERSED 0
#endif

/* Like PREFERRED_STACK_BOUNDARY but in units of bytes, not bits.  */
#define STACK_BYTES (PREFERRED_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
     PARALLEL if the arg is to be copied into multiple non-contiguous
     registers.  */
  rtx reg;
  /* Register to pass this argument in when generating tail call sequence.
     This is not the same register as for normal calls on machines with
     register windows.  */
  rtx tail_call_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;
  /* Place that this stack area has been saved, if needed.  */
  rtx save_area;
  /* 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;
  /* The amount that the stack pointer needs to be adjusted to
     force alignment for the next argument.  */
  struct args_size alignment_pad;
};

/* 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;

/* A bitmap of virtual-incoming stack space.  Bit is set if the corresponding
   stack location's tail call argument has been already stored into the stack.
   This bitmap is used to prevent sibling call optimization if function tries
   to use parent's incoming argument slots when they have been already
   overwritten with tail call arguments.  */
static sbitmap stored_args_map;

/* 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;

static int calls_function       PARAMS ((tree, int));
static int calls_function_1     PARAMS ((tree, int));

/* Nonzero if this is a call to a `const' function. */
#define ECF_CONST               1
/* Nonzero if this is a call to a `volatile' function.  */
#define ECF_NORETURN            2
/* Nonzero if this is a call to malloc or a related function. */
#define ECF_MALLOC              4
/* Nonzero if it is plausible that this is a call to alloca.  */
#define ECF_MAY_BE_ALLOCA       8
/* Nonzero if this is a call to a function that won't throw an exception.  */
#define ECF_NOTHROW             16
/* Nonzero if this is a call to setjmp or a related function.  */
#define ECF_RETURNS_TWICE       32
/* Nonzero if this is a call to `longjmp'.  */
#define ECF_LONGJMP             64
/* Nonzero if this is a syscall that makes a new process in the image of
   the current one.  */
#define ECF_FORK_OR_EXEC        128
#define ECF_SIBCALL             256
/* Nonzero if this is a call to "pure" function (like const function,
   but may read memory.  */
#define ECF_PURE                512

static void emit_call_1         PARAMS ((rtx, tree, tree, HOST_WIDE_INT,
                                         HOST_WIDE_INT, HOST_WIDE_INT, rtx,
                                         rtx, int, rtx, int));
static void precompute_register_parameters      PARAMS ((int,
                                                         struct arg_data *,
                                                         int *));
static void store_one_arg       PARAMS ((struct arg_data *, rtx, int, int,
                                         int));
static void store_unaligned_arguments_into_pseudos PARAMS ((struct arg_data *,
                                                            int));
static int finalize_must_preallocate            PARAMS ((int, int,
                                                         struct arg_data *,
                                                         struct args_size *));
static void precompute_arguments                PARAMS ((int, int,
                                                         struct arg_data *));
static int compute_argument_block_size          PARAMS ((int, 
                                                         struct args_size *,
                                                         int));
static void initialize_argument_information     PARAMS ((int,
                                                         struct arg_data *,
                                                         struct args_size *,
                                                         int, tree, tree,
                                                         CUMULATIVE_ARGS *,
                                                         int, rtx *, int *,
                                                         int *, int *));
static void compute_argument_addresses          PARAMS ((struct arg_data *,
                                                         rtx, int));
static rtx rtx_for_function_call                PARAMS ((tree, tree));
static void load_register_parameters            PARAMS ((struct arg_data *,
                                                         int, rtx *, int));
static int libfunc_nothrow                      PARAMS ((rtx));
static rtx emit_library_call_value_1            PARAMS ((int, rtx, rtx, int,
                                                         enum machine_mode,
                                                         int, va_list));
static int special_function_p                   PARAMS ((tree, int));
static int flags_from_decl_or_type              PARAMS ((tree));
static rtx try_to_integrate                     PARAMS ((tree, tree, rtx,
                                                         int, tree, rtx));
static int check_sibcall_argument_overlap_1     PARAMS ((rtx));
static int check_sibcall_argument_overlap       PARAMS ((rtx, struct arg_data *));

static int combine_pending_stack_adjustment_and_call
                                                PARAMS ((int, struct args_size *, int));

#ifdef REG_PARM_STACK_SPACE
static rtx save_fixed_argument_area     PARAMS ((int, rtx, int *, int *));
static void restore_fixed_argument_area PARAMS ((rtx, rtx, int, int));
#endif
\f
/* 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;
}

/* Recursive function to do the work of above function.  */

static int
calls_function_1 (exp, which)
     tree exp;
     int which;
{
  register int i;
  enum tree_code code = TREE_CODE (exp);
  int class = TREE_CODE_CLASS (code);
  int length = first_rtl_op (code);

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

  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)
               && (special_function_p (TREE_OPERAND (TREE_OPERAND (exp, 0), 0),
                                       0)
                   & ECF_MAY_BE_ALLOCA))
        return 1;

      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;
        register tree subblock;

        for (local = BLOCK_VARS (exp); local; local = TREE_CHAIN (local))
          if (DECL_INITIAL (local) != 0
              && calls_function_1 (DECL_INITIAL (local), which))
            return 1;

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

    case TREE_LIST:
      for (; exp != 0; exp = TREE_CHAIN (exp))
        if (calls_function_1 (TREE_VALUE (exp), which))
          return 1;
      return 0;

    default:
      break;
    }

  /* Only expressions, references, and blocks can contain calls.  */
  if (! IS_EXPR_CODE_CLASS (class) && class != 'r' && class != 'b')
    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;
}
\f
/* 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)
    /* If we are using registers for parameters, force the
       function address into a register now.  */
    funexp = ((SMALL_REGISTER_CLASSES && reg_parm_seen)
              ? force_not_mem (memory_address (FUNCTION_MODE, funexp))
              : 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);

      if (GET_CODE (static_chain_rtx) == REG)
        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.

   FNDECL is the declaration node of the function.  This is given to the
   macro RETURN_POPS_ARGS to determine whether this function pops its own args.

   FUNTYPE is the data type of the function.  This is given to the macro
   RETURN_POPS_ARGS to determine whether this function pops its own args.
   We used to allow an identifier for library functions, but that doesn't
   work when the return type is an aggregate type and the calling convention
   says that the pointer to this aggregate is to be popped by the callee.

   STACK_SIZE is the number of bytes of arguments on the stack,
   ROUNDED_STACK_SIZE is that number rounded up to
   PREFERRED_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.  */

static void
emit_call_1 (funexp, fndecl, funtype, stack_size, rounded_stack_size,
             struct_value_size, next_arg_reg, valreg, old_inhibit_defer_pop,
             call_fusage, ecf_flags)
     rtx funexp;
     tree fndecl ATTRIBUTE_UNUSED;
     tree funtype ATTRIBUTE_UNUSED;
     HOST_WIDE_INT stack_size ATTRIBUTE_UNUSED;
     HOST_WIDE_INT rounded_stack_size;
     HOST_WIDE_INT struct_value_size ATTRIBUTE_UNUSED;
     rtx next_arg_reg;
     rtx valreg;
     int old_inhibit_defer_pop;
     rtx call_fusage;
     int ecf_flags;
{
  rtx rounded_stack_size_rtx = GEN_INT (rounded_stack_size);
  rtx call_insn;
  int already_popped = 0;
  HOST_WIDE_INT n_popped = RETURN_POPS_ARGS (fndecl, funtype, stack_size);
#if defined (HAVE_call) && defined (HAVE_call_value)
  rtx struct_value_size_rtx;
  struct_value_size_rtx = GEN_INT (struct_value_size);
#endif

  /* 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);

#if defined (HAVE_sibcall_pop) && defined (HAVE_sibcall_value_pop)
  if ((ecf_flags & ECF_SIBCALL)
      && HAVE_sibcall_pop && HAVE_sibcall_value_pop
      && (RETURN_POPS_ARGS (fndecl, funtype, stack_size) > 0 
          || stack_size == 0))
    {
      rtx n_pop = GEN_INT (RETURN_POPS_ARGS (fndecl, 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_SIBCALL_VALUE_POP (valreg,
                                     gen_rtx_MEM (FUNCTION_MODE, funexp),
                                     rounded_stack_size_rtx, next_arg_reg,
                                     n_pop);
      else
        pat = GEN_SIBCALL_POP (gen_rtx_MEM (FUNCTION_MODE, funexp),
                               rounded_stack_size_rtx, next_arg_reg, n_pop);

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

#if defined (HAVE_call_pop) && defined (HAVE_call_value_pop)
/* If the target has "call" or "call_value" insns, then prefer them
   if no arguments are actually popped.  If the target does not have
   "call" or "call_value" insns, then we must use the popping versions
   even if the call has no arguments to pop.  */
#if defined (HAVE_call) && defined (HAVE_call_value)
  if (HAVE_call && HAVE_call_value && HAVE_call_pop && HAVE_call_value_pop
      && n_popped > 0)
#else
  if (HAVE_call_pop && HAVE_call_value_pop)
#endif
    {
      rtx n_pop = GEN_INT (n_popped);
      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),
                                  rounded_stack_size_rtx, next_arg_reg, n_pop);
      else
        pat = GEN_CALL_POP (gen_rtx_MEM (FUNCTION_MODE, funexp),
                            rounded_stack_size_rtx, next_arg_reg, n_pop);

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

#if defined (HAVE_sibcall) && defined (HAVE_sibcall_value)
  if ((ecf_flags & ECF_SIBCALL)
      && HAVE_sibcall && HAVE_sibcall_value)
    {
      if (valreg)
        emit_call_insn (GEN_SIBCALL_VALUE (valreg,
                                           gen_rtx_MEM (FUNCTION_MODE, funexp),
                                           rounded_stack_size_rtx,
                                           next_arg_reg, NULL_RTX));
      else
        emit_call_insn (GEN_SIBCALL (gen_rtx_MEM (FUNCTION_MODE, funexp),
                                     rounded_stack_size_rtx, next_arg_reg,
                                     struct_value_size_rtx));
    }
  else
#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),
                                        rounded_stack_size_rtx, next_arg_reg,
                                        NULL_RTX));
      else
        emit_call_insn (GEN_CALL (gen_rtx_MEM (FUNCTION_MODE, funexp),
                                  rounded_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 ();

  /* Mark memory as used for "pure" function call.  */
  if (ecf_flags & ECF_PURE)
    {
      call_fusage =  gen_rtx_EXPR_LIST (VOIDmode,
        gen_rtx_USE (VOIDmode,
                     gen_rtx_MEM (BLKmode,
                                  gen_rtx_SCRATCH (VOIDmode))), call_fusage);
    }

  /* 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 (ecf_flags & (ECF_CONST | ECF_PURE))
    CONST_CALL_P (call_insn) = 1;

  /* If this call can't throw, attach a REG_EH_REGION reg note to that
     effect.  */
  if (ecf_flags & ECF_NOTHROW)
    REG_NOTES (call_insn) = gen_rtx_EXPR_LIST (REG_EH_REGION, const0_rtx,
                                               REG_NOTES (call_insn));

  SIBLING_CALL_P (call_insn) = ((ecf_flags & ECF_SIBCALL) != 0);

  /* 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;

  if (n_popped > 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));
      rounded_stack_size -= n_popped;
      rounded_stack_size_rtx = GEN_INT (rounded_stack_size);
      stack_pointer_delta -= n_popped;
    }

  if (!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 (rounded_stack_size != 0)
        {
          if (flag_defer_pop && inhibit_defer_pop == 0
              && !(ecf_flags & (ECF_CONST | ECF_PURE)))
            pending_stack_adjust += rounded_stack_size;
          else
            adjust_stack (rounded_stack_size_rtx);
        }
    }
  /* When we accumulate outgoing args, we must avoid any stack manipulations.
     Restore the stack pointer to its original value now.  Usually
     ACCUMULATE_OUTGOING_ARGS targets don't get here, but there are exceptions.
     On  i386 ACCUMULATE_OUTGOING_ARGS can be enabled on demand, and
     popping variants of functions exist as well.

     ??? We may optimize similar to defer_pop above, but it is
     probably not worthwhile.
   
     ??? It will be worthwhile to enable combine_stack_adjustments even for
     such machines.  */
  else if (n_popped)
    anti_adjust_stack (GEN_INT (n_popped));
}

/* Determine if the function identified by NAME and FNDECL is one with
   special properties we wish to know about.

   For example, if the function might return more than one time (setjmp), then
   set RETURNS_TWICE to a nonzero value.

   Similarly set LONGJMP for if the function is in the longjmp family.

   Set MALLOC for any of the standard memory allocation functions which
   allocate from the heap.

   Set MAY_BE_ALLOCA for any memory allocation function that might allocate
   space from the stack such as alloca.  */

static int
special_function_p (fndecl, flags)
     tree fndecl;
     int flags;
{
  if (! (flags & ECF_MALLOC)
      && fndecl && DECL_NAME (fndecl)
      && IDENTIFIER_LENGTH (DECL_NAME (fndecl)) <= 17
      /* Exclude functions not at the file scope, or not `extern',
         since they are not the magic functions we would otherwise
         think they are.  */
      && DECL_CONTEXT (fndecl) == NULL_TREE && TREE_PUBLIC (fndecl))
    {
      char *name = IDENTIFIER_POINTER (DECL_NAME (fndecl));
      char *tname = name;

      /* 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.  */
      if (((IDENTIFIER_LENGTH (DECL_NAME (fndecl)) == 6
            && name[0] == 'a'
            && ! strcmp (name, "alloca"))
           || (IDENTIFIER_LENGTH (DECL_NAME (fndecl)) == 16
               && name[0] == '_'
               && ! strcmp (name, "__builtin_alloca"))))
        flags |= ECF_MAY_BE_ALLOCA;

      /* 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')
        {
          if ((tname[1] == 'e'
               && (! strcmp (tname, "setjmp")
                   || ! strcmp (tname, "setjmp_syscall")))
              || (tname[1] == 'i'
                  && ! strcmp (tname, "sigsetjmp"))
              || (tname[1] == 'a'
                  && ! strcmp (tname, "savectx")))
            flags |= ECF_RETURNS_TWICE;

          if (tname[1] == 'i'
              && ! strcmp (tname, "siglongjmp"))
            flags |= ECF_LONGJMP;
        }
      else if ((tname[0] == 'q' && tname[1] == 's'
                && ! strcmp (tname, "qsetjmp"))
               || (tname[0] == 'v' && tname[1] == 'f'
                   && ! strcmp (tname, "vfork")))
        flags |= ECF_RETURNS_TWICE;

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

      else if ((tname[0] == 'f' && tname[1] == 'o'
                && ! strcmp (tname, "fork"))
               /* Linux specific: __clone.  check NAME to insist on the
                  leading underscores, to avoid polluting the ISO / POSIX
                  namespace.  */
               || (name[0] == '_' && name[1] == '_'
                   && ! strcmp (tname, "clone"))
               || (tname[0] == 'e' && tname[1] == 'x' && tname[2] == 'e'
                   && tname[3] == 'c' && (tname[4] == 'l' || tname[4] == 'v')
                   && (tname[5] == '\0'
                       || ((tname[5] == 'p' || tname[5] == 'e')
                           && tname[6] == '\0'))))
        flags |= ECF_FORK_OR_EXEC;

      /* Do not add any more malloc-like functions to this list,
         instead mark them as malloc functions using the malloc attribute.
         Note, realloc is not suitable for attribute malloc since
         it may return the same address across multiple calls.
         C++ operator new is not suitable because it is not required
         to return a unique pointer; indeed, the standard placement new
         just returns its argument. */
      else if (TYPE_MODE (TREE_TYPE (TREE_TYPE (fndecl))) == Pmode
               && (! strcmp (tname, "malloc")
                   || ! strcmp (tname, "calloc")
                   || ! strcmp (tname, "strdup")))
        flags |= ECF_MALLOC;
    }
  return flags;
}

/* Return nonzero when tree represent call to longjmp.  */
int
setjmp_call_p (fndecl)
     tree fndecl;
{
  return special_function_p (fndecl, 0) & ECF_RETURNS_TWICE;
}

/* Detect flags (function attributes) from the function type node.  */
static int
flags_from_decl_or_type (exp)
     tree exp;
{
  int flags = 0;
  /* ??? We can't set IS_MALLOC for function types?  */
  if (DECL_P (exp))
    {
      /* The function exp may have the `malloc' attribute.  */
      if (DECL_P (exp) && DECL_IS_MALLOC (exp))
        flags |= ECF_MALLOC;

      /* The function exp may have the `pure' attribute.  */
      if (DECL_P (exp) && DECL_IS_PURE (exp))
        flags |= ECF_PURE;

      if (TREE_NOTHROW (exp))
        flags |= ECF_NOTHROW;
    }

  if (TREE_READONLY (exp) && !TREE_THIS_VOLATILE (exp))
    flags |= ECF_CONST;

  if (TREE_THIS_VOLATILE (exp))
    flags |= ECF_NORETURN;

  return flags;
}


/* Precompute all register parameters as described by ARGS, storing values
   into fields within the ARGS array.

   NUM_ACTUALS indicates the total number elements in the ARGS array.

   Set REG_PARM_SEEN if we encounter a register parameter.  */

static void
precompute_register_parameters (num_actuals, args, reg_parm_seen)
     int num_actuals;
     struct arg_data *args;
     int *reg_parm_seen;
{
  int i;

  *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
            && ((SMALL_REGISTER_CLASSES && *reg_parm_seen)
                || preserve_subexpressions_p ()))
          args[i].value = copy_to_mode_reg (args[i].mode, args[i].value);
      }
}

#ifdef 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.  */

static rtx
save_fixed_argument_area (reg_parm_stack_space, argblock,
                          low_to_save, high_to_save)
     int reg_parm_stack_space;
     rtx argblock;
     int *low_to_save;
     int *high_to_save;
{
  int i;
  rtx save_area = NULL_RTX;

  /* 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;

#ifdef ARGS_GROW_DOWNWARD
      stack_area
        = gen_rtx_MEM (save_mode,
                       memory_address (save_mode,
                                       plus_constant (argblock,
                                                      - *high_to_save)));
#else
      stack_area = gen_rtx_MEM (save_mode,
                                memory_address (save_mode,
                                                plus_constant (argblock,
                                                               *low_to_save)));
#endif
      if (save_mode == BLKmode)
        {
          save_area = assign_stack_temp (BLKmode, num_to_save, 0);
          /* Cannot use emit_block_move here because it can be done by a
             library call which in turn gets into this place again and deadly
             infinite recursion happens.  */
          move_by_pieces (validize_mem (save_area), stack_area, num_to_save,
                          PARM_BOUNDARY);
        }
      else
        {
          save_area = gen_reg_rtx (save_mode);
          emit_move_insn (save_area, stack_area);
        }
    }
  return save_area;
}

static void
restore_fixed_argument_area (save_area, argblock, high_to_save, low_to_save)
     rtx save_area;
     rtx argblock;
     int high_to_save;
     int low_to_save;
{
  enum machine_mode save_mode = GET_MODE (save_area);
#ifdef ARGS_GROW_DOWNWARD
  rtx stack_area
    = gen_rtx_MEM (save_mode,
                   memory_address (save_mode,
                                   plus_constant (argblock,
                                                  - high_to_save)));
#else
  rtx stack_area
    = gen_rtx_MEM (save_mode,
                   memory_address (save_mode,
                                   plus_constant (argblock,
                                                  low_to_save)));
#endif

  if (save_mode != BLKmode)
    emit_move_insn (stack_area, save_area);
  else
    /* Cannot use emit_block_move here because it can be done by a library
       call which in turn gets into this place again and deadly infinite
       recursion happens.  */
    move_by_pieces (stack_area, validize_mem (save_area),
                    high_to_save - low_to_save + 1, PARM_BOUNDARY);
}
#endif
          
/* If any elements in ARGS refer to parameters that are to be passed in
   registers, but not in memory, and whose alignment does not permit a
   direct copy into registers.  Copy the values into a group of pseudos
   which we will later copy into the appropriate hard registers. 

   Pseudos for each unaligned argument will be stored into the array
   args[argnum].aligned_regs.  The caller is responsible for deallocating
   the aligned_regs array if it is nonzero.  */

static void
store_unaligned_arguments_into_pseudos (args, num_actuals)
     struct arg_data *args;
     int num_actuals;
{
  int i, j;
     
  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))
            < (unsigned int) 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 *) xmalloc (sizeof (rtx)
                                                * args[i].n_aligned_regs);

        /* Structures smaller than a word are aligned to the least
           significant 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 = MIN (bytes * BITS_PER_UNIT, BITS_PER_WORD);
            int bitalign = TYPE_ALIGN (TREE_TYPE (args[i].tree_value));

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

            /* There is no need to restrict this code to loading items
               in TYPE_ALIGN sized hunks.  The bitfield instructions can
               load up entire word sized registers efficiently.

               ??? This may not be needed anymore.
               We use to emit a clobber here but that doesn't let later
               passes optimize the instructions we emit.  By storing 0 into
               the register later passes know the first AND to zero out the
               bitfield being set in the register is unnecessary.  The store
               of 0 will be deleted as will at least the first AND.  */

            emit_move_insn (reg, const0_rtx);

            bytes -= bitsize / BITS_PER_UNIT;
            store_bit_field (reg, bitsize, big_endian_correction, word_mode,
                             extract_bit_field (word, bitsize, 0, 1, NULL_RTX,
                                                word_mode, word_mode, bitalign,
                                                BITS_PER_WORD),
                             bitalign, BITS_PER_WORD);
          }
      }
}

/* Fill in ARGS_SIZE and ARGS array based on the parameters found in
   ACTPARMS. 

   NUM_ACTUALS is the total number of parameters.

   N_NAMED_ARGS is the total number of named arguments.

   FNDECL is the tree code for the target of this call (if known)

   ARGS_SO_FAR holds state needed by the target to know where to place
   the next argument.

   REG_PARM_STACK_SPACE is the number of bytes of stack space reserved
   for arguments which are passed in registers.

   OLD_STACK_LEVEL is a pointer to an rtx which olds the old stack level
   and may be modified by this routine.

   OLD_PENDING_ADJ, MUST_PREALLOCATE and FLAGS are pointers to integer
   flags which may may be modified by this routine.  */

static void
initialize_argument_information (num_actuals, args, args_size, n_named_args,
                                 actparms, fndecl, args_so_far,
                                 reg_parm_stack_space, old_stack_level,
                                 old_pending_adj, must_preallocate,
                                 ecf_flags)
     int num_actuals ATTRIBUTE_UNUSED;
     struct arg_data *args;
     struct args_size *args_size;
     int n_named_args ATTRIBUTE_UNUSED;
     tree actparms;
     tree fndecl;
     CUMULATIVE_ARGS *args_so_far;
     int reg_parm_stack_space;
     rtx *old_stack_level;
     int *old_pending_adj;
     int *must_preallocate;
     int *ecf_flags;
{
  /* 1 if scanning parms front to back, -1 if scanning back to front.  */
  int inc;

  /* Count arg position in order args appear.  */
  int argpos;

  struct args_size alignment_pad;
  int i;
  tree p;
  
  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 or from the back if necessary
     so that in any case the first arg to be pushed ends up at the front.  */

  if (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;
    }

  /* 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 || !COMPLETE_TYPE_P (type))
        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 (TREE_CODE (type) == UNION_TYPE && 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)))
          || TREE_ADDRESSABLE (type)
#ifdef FUNCTION_ARG_PASS_BY_REFERENCE
          || FUNCTION_ARG_PASS_BY_REFERENCE (*args_so_far, TYPE_MODE (type),
                                             type, argpos < n_named_args)
#endif
          )
        {
          /* If we're compiling a thunk, pass through invisible
             references instead of making a copy.  */
          if (current_function_is_thunk
#ifdef FUNCTION_ARG_CALLEE_COPIES
              || (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)))
                  && ! TREE_ADDRESSABLE (type))
#endif
              )
            {
              /* C++ uses a TARGET_EXPR to indicate that we want to make a
                 new object from the argument.  If we are passing by
                 invisible reference, the callee will do that for us, so we
                 can strip off the TARGET_EXPR.  This is not always safe,
                 but it is safe in the only case where this is a useful
                 optimization; namely, when the argument is a plain object.
                 In that case, the frontend is just asking the backend to
                 make a bitwise copy of the argument. */
                 
              if (TREE_CODE (args[i].tree_value) == TARGET_EXPR
                  && (DECL_P (TREE_OPERAND (args[i].tree_value, 1)))
                  && ! REG_P (DECL_RTL (TREE_OPERAND (args[i].tree_value, 1))))
                args[i].tree_value = TREE_OPERAND (args[i].tree_value, 1);

              args[i].tree_value = build1 (ADDR_EXPR,
                                           build_pointer_type (type),
                                           args[i].tree_value);
              type = build_pointer_type (type);
            }
          else
            {
              /* We make a copy of the object and pass the address to the
                 function being called.  */
              rtx copy;

              if (!COMPLETE_TYPE_P (type)
                  || TREE_CODE (TYPE_SIZE (type)) != INTEGER_CST
                  || (flag_stack_check && ! STACK_CHECK_BUILTIN
                      && (0 < compare_tree_int (TYPE_SIZE_UNIT (type),
                                                STACK_CHECK_MAX_VAR_SIZE))))
                {
                  /* 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)));
                  set_mem_attributes (copy, type, 1);
                }
              else
                copy = assign_temp (type, 0, 1, 0);

              store_expr (args[i].tree_value, copy, 0);
              *ecf_flags &= ~(ECF_CONST | ECF_PURE);

              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_INCOMING_ARG
      /* If this is a sibling call and the machine has register windows, the
         register window has to be unwinded before calling the routine, so
         arguments have to go into the incoming registers.  */
      args[i].tail_call_reg = FUNCTION_INCOMING_ARG (*args_so_far, mode, type,
                                             argpos < n_named_args);
#else
      args[i].tail_call_reg = args[i].reg;
#endif

#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 a (parallel [(expr_list (nil) ...) ...]),
         it means that we are to pass this arg in the register(s) designated
         by the PARALLEL, but also to pass it in the stack.  */
      if (args[i].reg && GET_CODE (args[i].reg) == PARALLEL
          && XEXP (XVECEXP (args[i].reg, 0, 0), 0) == 0)
        args[i].pass_on_stack = 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))
        *ecf_flags &= ~(ECF_CONST | ECF_PURE);

      /* Compute the stack-size of this argument.  */
      if (args[i].reg == 0 || args[i].partial != 0
          || reg_parm_stack_space > 0
          || 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, &alignment_pad);

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

      args[i].alignment_pad = alignment_pad;

      /* If a part of the arg was put into registers,
         don't include that part in the amount pushed.  */
      if (reg_parm_stack_space == 0 && ! 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));
      
      /* 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);
    }
}

/* Update ARGS_SIZE to contain the total size for the argument block.
   Return the original constant component of the argument block's size.

   REG_PARM_STACK_SPACE holds the number of bytes of stack space reserved
   for arguments passed in registers.  */

static int
compute_argument_block_size (reg_parm_stack_space, args_size,
                             preferred_stack_boundary)
     int reg_parm_stack_space;
     struct args_size *args_size;
     int preferred_stack_boundary ATTRIBUTE_UNUSED;
{
  int unadjusted_args_size = args_size->constant;

  /* For accumulate outgoing args mode we don't need to align, since the frame
     will be already aligned.  Align to STACK_BOUNDARY in order to prevent
     backends from generating missaligned frame sizes.  */
#ifdef STACK_BOUNDARY
  if (ACCUMULATE_OUTGOING_ARGS && preferred_stack_boundary > STACK_BOUNDARY)
    preferred_stack_boundary = STACK_BOUNDARY;
#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.  */

  if (args_size->var)
    {
      args_size->var = ARGS_SIZE_TREE (*args_size);
      args_size->constant = 0;

#ifdef PREFERRED_STACK_BOUNDARY
      preferred_stack_boundary /= BITS_PER_UNIT;
      if (preferred_stack_boundary > 1)
        {
          /* We don't handle this case yet.  To handle it correctly we have
             to add the delta, round and substract the delta.  
             Currently no machine description requires this support.  */
          if (stack_pointer_delta & (preferred_stack_boundary - 1))
            abort();
          args_size->var = round_up (args_size->var, preferred_stack_boundary);
        }
#endif

      if (reg_parm_stack_space > 0)
        {
          args_size->var
            = size_binop (MAX_EXPR, args_size->var,
                          ssize_int (reg_parm_stack_space));

#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,
                          ssize_int (reg_parm_stack_space));
#endif
        }
    }
  else
    {
#ifdef PREFERRED_STACK_BOUNDARY
      preferred_stack_boundary /= BITS_PER_UNIT;
      if (preferred_stack_boundary < 1)
        preferred_stack_boundary = 1;
      args_size->constant = (((args_size->constant
                               + stack_pointer_delta
                               + preferred_stack_boundary - 1)
                              / preferred_stack_boundary
                              * preferred_stack_boundary)
                             - stack_pointer_delta);
#endif

      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
    }
  return unadjusted_args_size;
}

/* Precompute parameters as needed for a function call.

   FLAGS is mask of ECF_* constants.

   NUM_ACTUALS is the number of arguments.

   ARGS is an array containing information for each argument; this routine
   fills in the INITIAL_VALUE and VALUE fields for each precomputed argument.  
   */

static void
precompute_arguments (flags, num_actuals, args)
     int flags;
     int num_actuals;
     struct arg_data *args;
{
  int i;

  /* 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.  (we have code to avoid
     such case by saving the ougoing stack arguments, but it results in
     worse code)  */

  for (i = 0; i < num_actuals; i++)
    if ((flags & (ECF_CONST | ECF_PURE))
        || calls_function (args[i].tree_value, !ACCUMULATE_OUTGOING_ARGS))
      {
        /* If this is an addressable type, we cannot pre-evaluate it.  */
        if (TREE_ADDRESSABLE (TREE_TYPE (args[i].tree_value)))
          abort ();

        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 ();

        args[i].initial_value = args[i].value
          = protect_from_queue (args[i].value, 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);
#ifdef PROMOTE_FOR_CALL_ONLY
            /* CSE will replace this only if it contains args[i].value
               pseudo, so convert it down to the declared mode using
               a SUBREG.  */
            if (GET_CODE (args[i].value) == REG
                && GET_MODE_CLASS (args[i].mode) == MODE_INT)
              {
                args[i].initial_value
                  = gen_rtx_SUBREG (TYPE_MODE (TREE_TYPE (args[i].tree_value)),
                                    args[i].value, 0);
                SUBREG_PROMOTED_VAR_P (args[i].initial_value) = 1;
                SUBREG_PROMOTED_UNSIGNED_P (args[i].initial_value)
                  = args[i].unsignedp;
              }
#endif
          }
      }
}

/* Given the current state of MUST_PREALLOCATE and information about
   arguments to a function call in NUM_ACTUALS, ARGS and ARGS_SIZE,
   compute and return the final value for MUST_PREALLOCATE.  */

static int
finalize_must_preallocate (must_preallocate, num_actuals, args, args_size)
     int must_preallocate;
     int num_actuals;
     struct arg_data *args;
     struct args_size *args_size;
{
  /* 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;
      int i;

      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;
    }
  return must_preallocate;
}

/* If we preallocated stack space, compute the address of each argument
   and store it into the ARGS array.

   We need not ensure it is a valid memory address here; it will be 
   validized when it is used.

   ARGBLOCK is an rtx for the address of the outgoing arguments.  */

static void
compute_argument_addresses (args, argblock, num_actuals)
     struct arg_data *args;
     rtx argblock;
     int num_actuals;
{
  if (argblock)
    {
      rtx arg_reg = argblock;
      int i, 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);
          set_mem_attributes (args[i].stack,
                              TREE_TYPE (args[i].tree_value), 1);

          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);
          set_mem_attributes (args[i].stack_slot,
                              TREE_TYPE (args[i].tree_value), 1);

          /* Function incoming arguments may overlap with sibling call
             outgoing arguments and we cannot allow reordering of reads
             from function arguments with stores to outgoing arguments
             of sibling calls.  */
          MEM_ALIAS_SET (args[i].stack) = 0;
          MEM_ALIAS_SET (args[i].stack_slot) = 0;
        }
    }
}
                                               
/* Given a FNDECL and EXP, return an rtx suitable for use as a target address
   in a call instruction.

   FNDECL is the tree node for the target function.  For an indirect call
   FNDECL will be NULL_TREE.

   EXP is the CALL_EXPR for this call.  */

static rtx
rtx_for_function_call (fndecl, exp)
     tree fndecl;
     tree exp;
{
  rtx funexp;

  /* 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.  */
    {
      rtx funaddr;
      push_temp_slots ();
      funaddr = funexp = 
          expand_expr (TREE_OPERAND (exp, 0), NULL_RTX, VOIDmode, 0);
      pop_temp_slots ();        /* FUNEXP can't be BLKmode */

      /* Check the function is executable.  */
      if (current_function_check_memory_usage)
        {
#ifdef POINTERS_EXTEND_UNSIGNED
          /* It might be OK to convert funexp in place, but there's
             a lot going on between here and when it happens naturally
             that this seems safer. */
          funaddr = convert_memory_address (Pmode, funexp);
#endif
          emit_library_call (chkr_check_exec_libfunc, 1,
                             VOIDmode, 1,
                             funaddr, Pmode);
        }
      emit_queue ();
    }
  return funexp;
}

/* 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.  */

static void
load_register_parameters (args, num_actuals, call_fusage, flags)
     struct arg_data *args;
     int num_actuals;
     rtx *call_fusage;
     int flags;
{
  int i, j;

#ifdef LOAD_ARGS_REVERSED
  for (i = num_actuals - 1; i >= 0; i--)
#else
  for (i = 0; i < num_actuals; i++)
#endif
    {
      rtx reg = ((flags & ECF_SIBCALL)
                 ? args[i].tail_call_reg : args[i].reg);
      int partial = args[i].partial;
      int nregs;

      if (reg)
        {
          /* 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));

          /* Handle calls that pass values in multiple non-contiguous
             locations.  The Irix 6 ABI has examples of this.  */

          if (GET_CODE (reg) == PARALLEL)
            emit_group_load (reg, args[i].value,
                             int_size_in_bytes (TREE_TYPE (args[i].tree_value)),
                             TYPE_ALIGN (TREE_TYPE (args[i].tree_value)));

          /* 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.  */

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

          /* 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]);

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

          /* Handle calls that pass values in multiple non-contiguous
             locations.  The Irix 6 ABI has examples of this.  */
          if (GET_CODE (reg) == PARALLEL)
            use_group_regs (call_fusage, reg);
          else if (nregs == -1)
            use_reg (call_fusage, reg);
          else
            use_regs (call_fusage, REGNO (reg), nregs == 0 ? 1 : nregs);
        }
    }
}

/* Try to integrate function.  See expand_inline_function for documentation
   about the parameters.  */

static rtx
try_to_integrate (fndecl, actparms, target, ignore, type, structure_value_addr)
     tree fndecl;
     tree actparms;
     rtx target;
     int ignore;
     tree type;
     rtx structure_value_addr;
{
  rtx temp;
  rtx before_call;
  int i;
  rtx old_stack_level = 0;
  int reg_parm_stack_space = 0;

#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

  before_call = get_last_insn ();

  timevar_push (TV_INTEGRATION);

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

  timevar_pop (TV_INTEGRATION);

  /* If inlining succeeded, return.  */
  if (temp != (rtx) (HOST_WIDE_INT) - 1)
    {
      if (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 first_insn
                = before_call ? NEXT_INSN (before_call) : get_insns ();
              rtx insn = NULL_RTX, seq;

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

              if (DECL_SAVED_INSNS (fndecl)->outgoing_args_size == 0)
                for (insn = first_insn; 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. 

                     Add the stack space reserved for register arguments, if
                     any, 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.  */

                  int adjust = (DECL_SAVED_INSNS (fndecl)->outgoing_args_size
                                + reg_parm_stack_space);

                  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, first_insn);
                  emit_stack_restore (SAVE_BLOCK, old_stack_level, NULL_RTX);
                }
            }
        }

      /* 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
      && optimize > 0 && !TREE_ADDRESSABLE (fndecl))
    {
      warning_with_decl (fndecl, "inlining failed in call to `%s'");
      warning ("called from here");
    }
  mark_addressable (fndecl);
  return (rtx) (HOST_WIDE_INT) - 1;
}

/* We need to pop PENDING_STACK_ADJUST bytes.  But, if the arguments
   wouldn't fill up an even multiple of PREFERRED_UNIT_STACK_BOUNDARY
   bytes, then we would need to push some additional bytes to pad the
   arguments.  So, we compute an adjust to the stack pointer for an
   amount that will leave the stack under-aligned by UNADJUSTED_ARGS_SIZE
   bytes.  Then, when the arguments are pushed the stack will be perfectly
   aligned.  ARGS_SIZE->CONSTANT is set to the number of bytes that should
   be popped after the call.  Returns the adjustment.  */

static int
combine_pending_stack_adjustment_and_call (unadjusted_args_size,
                                           args_size,
                                           preferred_unit_stack_boundary)
     int unadjusted_args_size;
     struct args_size *args_size;
     int preferred_unit_stack_boundary;
{
  /* The number of bytes to pop so that the stack will be
     under-aligned by UNADJUSTED_ARGS_SIZE bytes.  */
  HOST_WIDE_INT adjustment;
  /* The alignment of the stack after the arguments are pushed, if we
     just pushed the arguments without adjust the stack here.  */
  HOST_WIDE_INT unadjusted_alignment;

  unadjusted_alignment 
    = ((stack_pointer_delta + unadjusted_args_size)
       % preferred_unit_stack_boundary);

  /* We want to get rid of as many of the PENDING_STACK_ADJUST bytes
     as possible -- leaving just enough left to cancel out the
     UNADJUSTED_ALIGNMENT.  In other words, we want to ensure that the
     PENDING_STACK_ADJUST is non-negative, and congruent to
     -UNADJUSTED_ALIGNMENT modulo the PREFERRED_UNIT_STACK_BOUNDARY.  */

  /* Begin by trying to pop all the bytes.  */
  unadjusted_alignment 
    = (unadjusted_alignment 
       - (pending_stack_adjust % preferred_unit_stack_boundary));
  adjustment = pending_stack_adjust;
  /* Push enough additional bytes that the stack will be aligned
     after the arguments are pushed.  */
  if (unadjusted_alignment >= 0)
    adjustment -= preferred_unit_stack_boundary - unadjusted_alignment;
  else
    adjustment += unadjusted_alignment;
  
  /* Now, sets ARGS_SIZE->CONSTANT so that we pop the right number of
     bytes after the call.  The right number is the entire
     PENDING_STACK_ADJUST less our ADJUSTMENT plus the amount required
     by the arguments in the first place.  */
  args_size->constant 
    = pending_stack_adjust - adjustment + unadjusted_args_size;

  return adjustment;
}

/* Scan X expression if it does not dereference any argument slots
   we already clobbered by tail call arguments (as noted in stored_args_map
   bitmap).
   Return non-zero if X expression dereferences such argument slots,
   zero otherwise.  */

static int
check_sibcall_argument_overlap_1 (x)
     rtx x;
{
  RTX_CODE code;
  int i, j;
  unsigned int k;
  const char *fmt;

  if (x == NULL_RTX)
    return 0;

  code = GET_CODE (x);

  if (code == MEM)
    {
      if (XEXP (x, 0) == current_function_internal_arg_pointer)
        i = 0;
      else if (GET_CODE (XEXP (x, 0)) == PLUS &&
               XEXP (XEXP (x, 0), 0) ==
                 current_function_internal_arg_pointer &&
               GET_CODE (XEXP (XEXP (x, 0), 1)) == CONST_INT)
        i = INTVAL (XEXP (XEXP (x, 0), 1));
      else
        return 0;

      for (k = 0; k < GET_MODE_SIZE (GET_MODE (x)); k++)
        if (i + k < stored_args_map->n_bits
            && TEST_BIT (stored_args_map, i + k))
          return 1;

      return 0;
    }

  /* Scan all subexpressions. */
  fmt = GET_RTX_FORMAT (code);
  for (i = 0; i < GET_RTX_LENGTH (code); i++, fmt++)
    {
      if (*fmt == 'e')
        {
          if (check_sibcall_argument_overlap_1 (XEXP (x, i)))
            return 1;
        }
      else if (*fmt == 'E')
        {
          for (j = 0; j < XVECLEN (x, i); j++)
            if (check_sibcall_argument_overlap_1 (XVECEXP (x, i, j)))
              return 1;
        }
    }
  return 0;

}

/* Scan sequence after INSN if it does not dereference any argument slots
   we already clobbered by tail call arguments (as noted in stored_args_map
   bitmap).  Add stack slots for ARG to stored_args_map bitmap afterwards.
   Return non-zero if sequence after INSN dereferences such argument slots,
   zero otherwise.  */

static int
check_sibcall_argument_overlap (insn, arg)
     rtx insn;
     struct arg_data *arg;
{     
  int low, high;

  if (insn == NULL_RTX)
    insn = get_insns ();
  else
    insn = NEXT_INSN (insn);

  for (; insn; insn = NEXT_INSN (insn))
    if (INSN_P (insn) &&
        check_sibcall_argument_overlap_1 (PATTERN (insn)))
      break;

  low = arg->offset.constant;
  for (high = low + arg->size.constant; low < high; low++)
    SET_BIT (stored_args_map, low);
  return insn != NULL_RTX;
}

/* 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;
{
  /* Nonzero if we are currently expanding a call.  */
  static int currently_expanding_call = 0;

  /* List of actual parameters.  */
  tree actparms = TREE_OPERAND (exp, 1);
  /* RTX for the function to be called.  */
  rtx funexp;
  /* Sequence of insns to perform a tail recursive "call".  */
  rtx tail_recursion_insns = NULL_RTX;
  /* Sequence of insns to perform a normal "call".  */
  rtx normal_call_insns = NULL_RTX;
  /* Sequence of insns to perform a tail recursive "call".  */
  rtx tail_call_insns = NULL_RTX;
  /* 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;
  rtx insn;
  int try_tail_call = 1;
  int try_tail_recursion = 1;
  int pass;

  /* 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.  */
  HOST_WIDE_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;

  /* 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;
  struct args_size adjusted_args_size;
  /* Size of arguments before any adjustments (such as rounding).  */
  int unadjusted_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.  */

  /* 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).  */

  int must_preallocate = !PUSH_ARGS;

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

  /* Address of space preallocated for stack parms
     (on machines that lack push insns), or 0 if space not preallocated.  */
  rtx argblock = 0;

  /* Mask of ECF_ flags.  */
  int flags = 0;
  /* Nonzero if this is a call to an inline function.  */
  int is_integrable = 0;
#ifdef 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

  int initial_highest_arg_in_use = highest_outgoing_arg_in_use;
  char *initial_stack_usage_map = stack_usage_map;
  int old_stack_arg_under_construction = 0;

  rtx old_stack_level = 0;
  int old_pending_adj = 0;
  int old_inhibit_defer_pop = inhibit_defer_pop;
  int old_stack_allocated;
  rtx call_fusage;
  register tree p;
  register int i;
  /* The alignment of the stack, in bits.  */
  HOST_WIDE_INT preferred_stack_boundary;
  /* The alignment of the stack, in bytes.  */
  HOST_WIDE_INT preferred_unit_stack_boundary;

  /* The value of the function call can be put in a hard register.  But
     if -fcheck-memory-usage, code which invokes functions (and thus
     damages some hard registers) can be inserted before using the value.
     So, target is always a pseudo-register in that case.  */
  if (current_function_check_memory_usage)
    target = 0;

  /* See if this is "nothrow" function call.  */
  if (TREE_NOTHROW (exp))
    flags |= ECF_NOTHROW;

  /* 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.  */

  fndecl = get_callee_fndecl (exp);
  if (fndecl)
    {
      if (!flag_no_inline
          && fndecl != current_function_decl
          && DECL_INLINE (fndecl)
          && DECL_SAVED_INSNS (fndecl)
          && DECL_SAVED_INSNS (fndecl)->inlinable)
        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
              && optimize > 0)
            {
              warning_with_decl (fndecl, "can't inline call to `%s'");
              warning ("called from here");
            }
          mark_addressable (fndecl);
        }

      flags |= flags_from_decl_or_type (fndecl);
    }

  /* If we don't have specific function to call, see if we have a 
     attributes set in the type.  */
  else
    {
      p = TREE_OPERAND (exp, 0);
      flags |= flags_from_decl_or_type (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

#ifndef OUTGOING_REG_PARM_STACK_SPACE
  if (reg_parm_stack_space > 0 && PUSH_ARGS)
    must_preallocate = 1;
#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.  */
      flags &= ~(ECF_CONST | ECF_PURE);

#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 to hold the value.  */
            tree d;

            /* 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 ();

            /* This DECL is just something to feed to mark_addressable;
               it doesn't get pushed.  */
            d = build_decl (VAR_DECL, NULL_TREE, TREE_TYPE (exp));
            DECL_RTL (d) = assign_temp (TREE_TYPE (exp), 1, 0, 1);
            mark_addressable (d);
            mark_temp_addr_taken (DECL_RTL (d));
            structure_value_addr = XEXP (DECL_RTL (d), 0);
            TREE_USED (d) = 1;
            target = 0;
          }
      }
#endif /* not PCC_STATIC_STRUCT_RETURN */
    }

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

  if (is_integrable)
    {
      rtx temp = try_to_integrate (fndecl, actparms, target,
                                   ignore, TREE_TYPE (exp),
                                   structure_value_addr);
      if (temp != (rtx) (HOST_WIDE_INT) - 1)
        return temp;
    }

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

  /* Figure out the amount to which the stack should be aligned.  */
#ifdef PREFERRED_STACK_BOUNDARY
  preferred_stack_boundary = PREFERRED_STACK_BOUNDARY;
#else
  preferred_stack_boundary = STACK_BOUNDARY;
#endif

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

  /* See if this is a call to a function that can return more than once
     or a call to longjmp or malloc.  */
  flags |= special_function_p (fndecl, flags);

  if (flags & ECF_MAY_BE_ALLOCA)
    current_function_calls_alloca = 1;

  /* 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
                  || (ACCUMULATE_OUTGOING_ARGS
                      && stack_arg_under_construction
                      && structure_value_addr == virtual_outgoing_args_rtx)
                  ? 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, num_actuals = 0; p; p = TREE_CHAIN (p))
    num_actuals++;

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

     If PRETEND_OUTGOING_VARARGS_NAMED is set and STRICT_ARGUMENT_NAMING is
     zero, 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 PRETEND_OUTGOING_VARARGS_NAMED is not set, we do not have any
     reliable way to pass unnamed args in registers, so we must force
     them into memory.  */

  if ((STRICT_ARGUMENT_NAMING
       || ! PRETEND_OUTGOING_VARARGS_NAMED)
      && TYPE_ARG_TYPES (funtype) != 0)
    n_named_args
      = (list_length (TYPE_ARG_TYPES (funtype))
         /* Don't include the last named arg.  */
         - (STRICT_ARGUMENT_NAMING ? 0 : 1)
         /* Count the struct value address, if it is passed as a parm.  */
         + structure_value_addr_parm);
  else
    /* If we know nothing, treat all args as named.  */
    n_named_args = num_actuals;

  /* Start updating where the next arg would go.

     On some machines (such as the PA) indirect calls have a different
     calling convention than normal calls.  The last argument in
     INIT_CUMULATIVE_ARGS tells the backend if this is an indirect call
     or not.  */
  INIT_CUMULATIVE_ARGS (args_so_far, funtype, NULL_RTX, (fndecl == 0));


  /* 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));

  /* Build up entries inthe ARGS array, compute the size of the arguments
     into ARGS_SIZE, etc.  */
  initialize_argument_information (num_actuals, args, &args_size,
                                   n_named_args, actparms, fndecl,
                                   &args_so_far, reg_parm_stack_space,
                                   &old_stack_level, &old_pending_adj,
                                   &must_preallocate, &flags);

  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.   */

      flags &= ~(ECF_CONST | ECF_PURE);
      must_preallocate = 1;
    }

  /* Now make final decision about preallocating stack space.  */
  must_preallocate = finalize_must_preallocate (must_preallocate,
                                                num_actuals, args,
                                                &args_size);

  /* 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
          || (!ACCUMULATE_OUTGOING_ARGS && args_size.constant)))
    structure_value_addr = copy_to_reg (structure_value_addr);

  /* Tail calls can make things harder to debug, and we're traditionally
     pushed these optimizations into -O2.  Don't try if we're already
     expanding a call, as that means we're an argument.  Similarly, if
     there's pending loops or cleanups we know there's code to follow
     the call.

     If rtx_equal_function_value_matters is false, that means we've 
     finished with regular parsing.  Which means that some of the
     machinery we use to generate tail-calls is no longer in place.
     This is most often true of sjlj-exceptions, which we couldn't
     tail-call to anyway.  */

  if (currently_expanding_call++ != 0
      || !flag_optimize_sibling_calls
      || !rtx_equal_function_value_matters
      || !stmt_loop_nest_empty ()
      || any_pending_cleanups (1)
      || args_size.var)
    try_tail_call = try_tail_recursion = 0;

  /* Tail recursion fails, when we are not dealing with recursive calls.  */
  if (!try_tail_recursion
      || TREE_CODE (TREE_OPERAND (exp, 0)) != ADDR_EXPR
      || TREE_OPERAND (TREE_OPERAND (exp, 0), 0) != current_function_decl)
    try_tail_recursion = 0;

  /*  Rest of purposes for tail call optimizations to fail.  */
  if (
#ifdef HAVE_sibcall_epilogue
      !HAVE_sibcall_epilogue
#else
      1
#endif
      || !try_tail_call
      /* Doing sibling call optimization needs some work, since
         structure_value_addr can be allocated on the stack.
         It does not seem worth the effort since few optimizable
         sibling calls will return a structure.  */
      || structure_value_addr != NULL_RTX
      /* If the register holding the address is a callee saved
         register, then we lose.  We have no way to prevent that,
         so we only allow calls to named functions.  */
      /* ??? This could be done by having the insn constraints
         use a register class that is all call-clobbered.  Any
         reload insns generated to fix things up would appear
         before the sibcall_epilogue.  */
      || fndecl == NULL_TREE
      || (flags & (ECF_RETURNS_TWICE | ECF_LONGJMP))
      || !FUNCTION_OK_FOR_SIBCALL (fndecl)
      /* If this function requires more stack slots than the current
         function, we cannot change it into a sibling call.  */
      || args_size.constant > current_function_args_size
      /* If the callee pops its own arguments, then it must pop exactly
         the same number of arguments as the current function.  */
      || RETURN_POPS_ARGS (fndecl, funtype, args_size.constant)
         != RETURN_POPS_ARGS (current_function_decl,
                              TREE_TYPE (current_function_decl),
                              current_function_args_size))
  try_tail_call = 0;

  if (try_tail_call || try_tail_recursion)
    {
      int end, inc;
      actparms = NULL_TREE;
      /* Ok, we're going to give the tail call the old college try.
         This means we're going to evaluate the function arguments
         up to three times.  There are two degrees of badness we can
         encounter, those that can be unsaved and those that can't.
         (See unsafe_for_reeval commentary for details.)

         Generate a new argument list.  Pass safe arguments through
         unchanged.  For the easy badness wrap them in UNSAVE_EXPRs.  
         For hard badness, evaluate them now and put their resulting
         rtx in a temporary VAR_DECL.

         initialize_argument_information has ordered the array for the
         order to be pushed, and we must remember this when reconstructing
         the original argument orde.  */

      if (PUSH_ARGS_REVERSED)
        {
          inc = 1;
          i = 0;
          end = num_actuals;
        }
      else
          {
          inc = -1;
          i = num_actuals - 1;
          end = -1;
        }

      for (; i != end; i += inc)
        {
          switch (unsafe_for_reeval (args[i].tree_value))
            {
          case 0: /* Safe.  */
            break;

          case 1: /* Mildly unsafe.  */
            args[i].tree_value = unsave_expr (args[i].tree_value);
            break;

          case 2: /* Wildly unsafe.  */
            {
              tree var = build_decl (VAR_DECL, NULL_TREE,
                                       TREE_TYPE (args[i].tree_value));
                DECL_RTL (var) = expand_expr (args[i].tree_value, NULL_RTX,
                                            VOIDmode, EXPAND_NORMAL);
                args[i].tree_value = var;
            }
            break;

          default:
            abort ();
          }
          /* We need to build actparms for optimize_tail_recursion.  We can
             safely trash away TREE_PURPOSE, since it is unused by this
             function.  */
          if (try_tail_recursion)
            actparms = tree_cons (NULL_TREE, args[i].tree_value, actparms);
        }
      /* Expanding one of those dangerous arguments could have added
         cleanups, but otherwise give it a whirl.  */
      if (any_pending_cleanups (1))
        try_tail_call = try_tail_recursion = 0;
    }

  /* Generate a tail recursion sequence when calling ourselves.  */

  if (try_tail_recursion)
    {
      /* We want to emit any pending stack adjustments before the tail
         recursion "call".  That way we know any adjustment after the tail
         recursion call can be ignored if we indeed use the tail recursion
         call expansion.  */
      int save_pending_stack_adjust = pending_stack_adjust;
      int save_stack_pointer_delta = stack_pointer_delta;

      /* Use a new sequence to hold any RTL we generate.  We do not even
         know if we will use this RTL yet.  The final decision can not be
         made until after RTL generation for the entire function is
         complete.  */
      start_sequence ();
      /* If expanding any of the arguments creates cleanups, we can't
         do a tailcall.  So, we'll need to pop the pending cleanups
         list.  If, however, all goes well, and there are no cleanups
         then the call to expand_start_target_temps will have no
         effect.  */
      expand_start_target_temps ();
      if (optimize_tail_recursion (actparms, get_last_insn ()))
        {
          if (any_pending_cleanups (1))
            try_tail_call = try_tail_recursion = 0;
          else
            tail_recursion_insns = get_insns ();
        }
      expand_end_target_temps ();
      end_sequence ();

      /* Restore the original pending stack adjustment for the sibling and
         normal call cases below.  */
      pending_stack_adjust = save_pending_stack_adjust;
      stack_pointer_delta = save_stack_pointer_delta;
    }

  if (profile_arc_flag && (flags & ECF_FORK_OR_EXEC))
    {
      /* A fork duplicates the profile information, and an exec discards
         it.  We can't rely on fork/exec to be paired.  So write out the
         profile information we have gathered so far, and clear it.  */
      /* ??? When Linux's __clone is called with CLONE_VM set, profiling
         is subject to race conditions, just as with multithreaded
         programs.  */

      emit_library_call (gen_rtx_SYMBOL_REF (Pmode, "__bb_fork_func"), 0,
                         VOIDmode, 0);
    }

  /* Ensure current function's preferred stack boundary is at least
     what we need.  We don't have to increase alignment for recursive
     functions.  */
  if (cfun->preferred_stack_boundary < preferred_stack_boundary
      && fndecl != current_function_decl)
    cfun->preferred_stack_boundary = preferred_stack_boundary;

  preferred_unit_stack_boundary = preferred_stack_boundary / BITS_PER_UNIT;

  function_call_count++;

  /* We want to make two insn chains; one for a sibling call, the other
     for a normal call.  We will select one of the two chains after
     initial RTL generation is complete.  */
  for (pass = 0; pass < 2; pass++)
    {
      int sibcall_failure = 0;
      /* We want to emit ay pending stack adjustments before the tail
         recursion "call".  That way we know any adjustment after the tail
         recursion call can be ignored if we indeed use the tail recursion
         call expansion.  */
      int save_pending_stack_adjust = 0;
      int save_stack_pointer_delta = 0;
      rtx insns;
      rtx before_call, next_arg_reg;

      if (pass == 0)
        {
          if (! try_tail_call)
            continue;

          /* Emit any queued insns now; otherwise they would end up in
             only one of the alternates.  */
          emit_queue ();

          /* State variables we need to save and restore between
             iterations.  */
          save_pending_stack_adjust = pending_stack_adjust;
          save_stack_pointer_delta = stack_pointer_delta;
        }
      if (pass)
        flags &= ~ECF_SIBCALL;
      else
        flags |= ECF_SIBCALL;

      /* Other state variables that we must reinitialize each time
         through the loop (that are not initialized by the loop itself).  */
      argblock = 0;
      call_fusage = 0;

      /* Start a new sequence for the normal call case. 

         From this point on, if the sibling call fails, we want to set
         sibcall_failure instead of continuing the loop.  */
      start_sequence ();

      if (pass == 0)
        {
          /* We know at this point that there are not currently any
             pending cleanups.  If, however, in the process of evaluating
             the arguments we were to create some, we'll need to be
             able to get rid of them.  */
          expand_start_target_temps ();
        }

      /* 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 (flags & (ECF_CONST | ECF_PURE))
        NO_DEFER_POP;

      /* 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 or if we are expanding a sibling
         call sequence.  */
      if (pending_stack_adjust >= 32
          || (pending_stack_adjust > 0 && (flags & ECF_MAY_BE_ALLOCA))
          || pass == 0)
        do_pending_stack_adjust ();

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


#ifdef FINAL_REG_PARM_STACK_SPACE
      reg_parm_stack_space = FINAL_REG_PARM_STACK_SPACE (args_size.constant,
                                                         args_size.var);
#endif
      /* Precompute any arguments as needed.  */
      if (pass)
        precompute_arguments (flags, num_actuals, args);

      /* Now we are about to start emitting insns that can be deleted
         if a libcall is deleted.  */
      if (flags & (ECF_CONST | ECF_PURE | ECF_MALLOC))
        start_sequence ();

      adjusted_args_size = args_size;
      /* 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.  When generating a sibcall
         pattern, do not round up, since we'll be re-using whatever space our
         caller provided.  */
      unadjusted_args_size
        = compute_argument_block_size (reg_parm_stack_space, &adjusted_args_size,
                                       (pass == 0 ? 0
                                        : preferred_stack_boundary));

      old_stack_allocated =  stack_pointer_delta - pending_stack_adjust;

      /* The argument block when performing a sibling call is the
         incoming argument block.  */
      if (pass == 0)
        {
          argblock = virtual_incoming_args_rtx;
          stored_args_map = sbitmap_alloc (args_size.constant);
          sbitmap_zero (stored_args_map);
        }

      /* If we have no actual push instructions, or shouldn't use them,
         make space for all args right now.  */
      else if (adjusted_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;
              /* 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;
            }
          argblock = push_block (ARGS_SIZE_RTX (adjusted_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 = adjusted_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)
            {
              if (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.  */

#ifndef 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
                {
                  if (inhibit_defer_pop == 0)
                    {
                      /* Try to reuse some or all of the pending_stack_adjust
                         to get this space.  */
                      needed
                        = (combine_pending_stack_adjustment_and_call 
                           (unadjusted_args_size,
                            &adjusted_args_size,
                            preferred_unit_stack_boundary));

                      /* combine_pending_stack_adjustment_and_call computes
                         an adjustment before the arguments are allocated.
                         Account for them and see whether or not the stack
                         needs to go up or down.  */
                      needed = unadjusted_args_size - needed;

                      if (needed < 0)
                        {
                          /* We're releasing stack space.  */
                          /* ??? We can avoid any adjustment at all if we're
                             already aligned.  FIXME.  */
                          pending_stack_adjust = -needed;
                          do_pending_stack_adjust ();
                          needed = 0;
                        }
                      else 
                        /* We need to allocate space.  We'll do that in
                           push_block below.  */
                        pending_stack_adjust = 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);

                  /* 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)
                    {
#ifndef OUTGOING_REG_PARM_STACK_SPACE
                      rtx push_size = GEN_INT (reg_parm_stack_space
                                               + adjusted_args_size.constant);
#else
                      rtx push_size = GEN_INT (adjusted_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;
                      }
                }
            }
        }

      compute_argument_addresses (args, argblock, num_actuals);

#ifdef PREFERRED_STACK_BOUNDARY
      /* If we push args individually in reverse order, perform stack alignment
         before the first push (the last arg).  */
      if (PUSH_ARGS_REVERSED && argblock == 0
          && adjusted_args_size.constant != unadjusted_args_size)
        {
          /* When the stack adjustment is pending, we get better code
             by combining the adjustments.  */
          if (pending_stack_adjust 
              && ! (flags & (ECF_CONST | ECF_PURE))
              && ! inhibit_defer_pop)
            {
              pending_stack_adjust
                = (combine_pending_stack_adjustment_and_call 
                   (unadjusted_args_size,
                    &adjusted_args_size,
                    preferred_unit_stack_boundary));
              do_pending_stack_adjust ();
            }
          else if (argblock == 0)
            anti_adjust_stack (GEN_INT (adjusted_args_size.constant
                                        - unadjusted_args_size));
        }
      /* Now that the stack is properly aligned, pops can't safely
         be deferred during the evaluation of the arguments.  */
      NO_DEFER_POP;
#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;

      funexp = rtx_for_function_call (fndecl, exp);

      /* 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, (pass == 0));
          else
            valreg = hard_function_value (TREE_TYPE (exp), fndecl, (pass == 0));
        }

      /* Precompute all register parameters.  It isn't safe to compute anything
         once we have started filling any specific hard regs.  */
      precompute_register_parameters (num_actuals, args, &reg_parm_seen);

#ifdef REG_PARM_STACK_SPACE
      /* Save the fixed argument area if it's part of the caller's frame and
         is clobbered by argument setup for this call.  */
      if (ACCUMULATE_OUTGOING_ARGS && pass)
        save_area = save_fixed_argument_area (reg_parm_stack_space, argblock,
                                              &low_to_save, &high_to_save);
#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)
          {
            rtx before_arg = get_last_insn ();

            store_one_arg (&args[i], argblock, flags,
                           adjusted_args_size.var != 0, reg_parm_stack_space);
            if (pass == 0 &&
                check_sibcall_argument_overlap (before_arg, &args[i]))
              sibcall_failure = 1;
          }

      /* 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.  */
      if (STRICT_ALIGNMENT)
        store_unaligned_arguments_into_pseudos (args, num_actuals);

      /* 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)
            {
              rtx before_arg = get_last_insn ();

              store_one_arg (&args[i], argblock, flags,
                             adjusted_args_size.var != 0, reg_parm_stack_space);
              if (pass == 0 &&
                  check_sibcall_argument_overlap (before_arg, &args[i]))
                sibcall_failure = 1;
            }

#ifdef PREFERRED_STACK_BOUNDARY
      /* If we pushed args in forward order, perform stack alignment
         after pushing the last arg.  */
      if (!PUSH_ARGS_REVERSED && argblock == 0)
        anti_adjust_stack (GEN_INT (adjusted_args_size.constant
                                    - unadjusted_args_size));
#endif

      /* If register arguments require space on the stack and stack space
         was not preallocated, allocate stack space here for arguments
         passed in registers.  */
#ifdef OUTGOING_REG_PARM_STACK_SPACE
      if (!ACCUMULATE_OUTGOING_ARGS
           && 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 (pass != 0 && structure_value_addr && ! structure_value_addr_parm)
        {
          emit_move_insn (struct_value_rtx,
                          force_reg (Pmode,
                                     force_operand (structure_value_addr,
                                                    NULL_RTX)));

          /* Mark the memory for the aggregate as write-only.  */
          if (current_function_check_memory_usage)
            emit_library_call (chkr_set_right_libfunc, 1,
                               VOIDmode, 3,
                               structure_value_addr, ptr_mode, 
                               GEN_INT (struct_value_size),
                               TYPE_MODE (sizetype),
                               GEN_INT (MEMORY_USE_WO),
                               TYPE_MODE (integer_type_node));

          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);

      load_register_parameters (args, num_actuals, &call_fusage, flags);
     
      /* Perform postincrements before actually calling the function.  */
      emit_queue ();

      /* Save a pointer to the last insn before the call, so that we can
         later safely search backwards to find the CALL_INSN.  */
      before_call = get_last_insn ();

      /* Set up next argument register.  For sibling calls on machines
         with register windows this should be the incoming register.  */
#ifdef FUNCTION_INCOMING_ARG
      if (pass == 0)
        next_arg_reg = FUNCTION_INCOMING_ARG (args_so_far, VOIDmode,
                                              void_type_node, 1);
      else
#endif
        next_arg_reg = FUNCTION_ARG (args_so_far, VOIDmode,
                                     void_type_node, 1);

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

#ifdef PREFERRED_STACK_BOUNDARY
      /* Stack must be properly aligned now.  */
      if (pass && stack_pointer_delta % preferred_unit_stack_boundary)
        abort ();
#endif

      /* Generate the actual call instruction.  */
      emit_call_1 (funexp, fndecl, funtype, unadjusted_args_size,
                   adjusted_args_size.constant, struct_value_size,
                   next_arg_reg, valreg, old_inhibit_defer_pop, call_fusage,
                   flags);

      /* Verify that we've deallocated all the stack we used.  */
      if (pass
          && old_stack_allocated != stack_pointer_delta - pending_stack_adjust)
        abort();

      /* 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.  Disable for PARALLEL return values, because
         we have no way to move such values into a pseudo register.  */
      if (pass
          && (flags & (ECF_CONST | ECF_PURE))
          && valreg != 0 && GET_CODE (valreg) != PARALLEL)
        {
          rtx note = 0;
          rtx temp = gen_reg_rtx (GET_MODE (valreg));
          rtx insns;

          /* Mark the return value as a pointer if needed.  */
          if (TREE_CODE (TREE_TYPE (exp)) == POINTER_TYPE)
            mark_reg_pointer (temp, TYPE_ALIGN (TREE_TYPE (TREE_TYPE (exp))));

          /* Construct an "equal form" for the value which mentions all the
             arguments in order as well as the function name.  */
          for (i = 0; i < num_actuals; i++)
            note = gen_rtx_EXPR_LIST (VOIDmode, args[i].initial_value, note);
          note = gen_rtx_EXPR_LIST (VOIDmode, funexp, note);

          insns = get_insns ();
          end_sequence ();

          if (flags & ECF_PURE)
            note = gen_rtx_EXPR_LIST (VOIDmode,
               gen_rtx_USE (VOIDmode,
                            gen_rtx_MEM (BLKmode,
                                         gen_rtx_SCRATCH (VOIDmode))), note);

          emit_libcall_block (insns, temp, valreg, note);
  
          valreg = temp;
        }
      else if (flags & (ECF_CONST | ECF_PURE))
        {
          /* Otherwise, just write out the sequence without a note.  */
          rtx insns = get_insns ();

          end_sequence ();
          emit_insns (insns);
        }
      else if (flags & ECF_MALLOC)
        {
          rtx temp = gen_reg_rtx (GET_MODE (valreg));
          rtx last, insns;

          /* The return value from a malloc-like function is a pointer. */
          if (TREE_CODE (TREE_TYPE (exp)) == POINTER_TYPE)
            mark_reg_pointer (temp, BIGGEST_ALIGNMENT);

          emit_move_insn (temp, valreg);

          /* The return value from a malloc-like function can not alias
             anything else.  */
          last = get_last_insn ();
          REG_NOTES (last) = 
            gen_rtx_EXPR_LIST (REG_NOALIAS, temp, REG_NOTES (last));

          /* Write out the sequence.  */
          insns = get_insns ();
          end_sequence ();
          emit_insns (insns);
          valreg = temp;
        }

      /* For calls to `setjmp', etc., inform flow.c it should complain
         if nonvolatile values are live.  For functions that cannot return,
         inform flow that control does not fall through.  */

      if ((flags & (ECF_RETURNS_TWICE | ECF_NORETURN | ECF_LONGJMP)) || pass == 0)
        {
          /* The barrier or NOTE_INSN_SETJMP note must be emitted
             immediately after the CALL_INSN.  Some ports emit more
             than just a CALL_INSN above, so we must search for it here.  */

          rtx last = get_last_insn ();
          while (GET_CODE (last) != CALL_INSN)
            {
              last = PREV_INSN (last);
              /* There was no CALL_INSN?  */
              if (last == before_call)
                abort ();
            }

          if (flags & ECF_RETURNS_TWICE)
            {
              emit_note_after (NOTE_INSN_SETJMP, last);
              current_function_calls_setjmp = 1;
            }
          else
            emit_barrier_after (last);
        }

      if (flags & ECF_LONGJMP)
        current_function_calls_longjmp = 1;

      /* If this function is returning into a memory location marked as
         readonly, it means it is initializing that location.  But we normally
         treat functions as not clobbering such locations, so we need to
         specify that this one does.  */
      if (target != 0 && GET_CODE (target) == MEM
          && structure_value_addr != 0 && RTX_UNCHANGING_P (target))
        emit_insn (gen_rtx_CLOBBER (VOIDmode, target));

      /* 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.
         We need to double check this and see if it matters anymore.  */
      if (any_pending_cleanups (1))
        {
          if (target && REG_P (target)
              && REGNO (target) < FIRST_PSEUDO_REGISTER)
            target = 0;
          sibcall_failure = 1;
        }

      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));
              set_mem_attributes (target, exp, 1);
            }
        }
      else if (pcc_struct_value)
        {
          /* This is the special C++ case where we need to
             know what the true target was.  We take care to
             never use this value more than once in one expression.  */
          target = gen_rtx_MEM (TYPE_MODE (TREE_TYPE (exp)),
                                copy_to_reg (valreg));
          set_mem_attributes (target, exp, 1);
        }
      /* Handle calls that return values in multiple non-contiguous locations.
         The Irix 6 ABI has examples of this.  */
      else if (GET_CODE (valreg) == PARALLEL)
        {
          int bytes = int_size_in_bytes (TREE_TYPE (exp));

          if (target == 0)
            {
              target = assign_stack_temp (TYPE_MODE (TREE_TYPE (exp)),
                                          bytes, 0);
              MEM_SET_IN_STRUCT_P (target, AGGREGATE_TYPE_P (TREE_TYPE (exp)));
              preserve_temp_slots (target);
            }

          if (! rtx_equal_p (target, valreg))
            emit_group_store (target, valreg, bytes,
                              TYPE_ALIGN (TREE_TYPE (exp)));

          /* We can not support sibling calls for this case.  */
          sibcall_failure = 1;
        }
      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 if (TYPE_MODE (TREE_TYPE (exp)) == BLKmode)
        target = copy_blkmode_from_reg (target, valreg, TREE_TYPE (exp));
      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
          && TYPE_MODE (TREE_TYPE (exp)) != BLKmode
          && 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 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;
          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;
          sibcall_failure = 1;
        }
      else if (ACCUMULATE_OUTGOING_ARGS && pass)
        {
#ifdef REG_PARM_STACK_SPACE
          if (save_area)
            {
              restore_fixed_argument_area (save_area, argblock,
                                           high_to_save, low_to_save);
            }
#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);
              }

          highest_outgoing_arg_in_use = initial_highest_arg_in_use;
          stack_usage_map = initial_stack_usage_map;
        }

      /* 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 ((flags & ECF_MAY_BE_ALLOCA) && nonlocal_goto_handler_slots != 0)
        emit_stack_save (SAVE_NONLOCAL, &nonlocal_goto_stack_level, NULL_RTX);

      pop_temp_slots ();

      /* Free up storage we no longer need.  */
      for (i = 0; i < num_actuals; ++i)
        if (args[i].aligned_regs)
          free (args[i].aligned_regs);

      if (pass == 0)
        {
          /* Undo the fake expand_start_target_temps we did earlier.  If
             there had been any cleanups created, we've already set
             sibcall_failure.  */
          expand_end_target_temps ();
        }

      insns = get_insns ();
      end_sequence ();

      if (pass == 0)
        {
          tail_call_insns = insns;

          /* If something prevents making this a sibling call,
             zero out the sequence.  */
          if (sibcall_failure)
            tail_call_insns = NULL_RTX;
          /* Restore the pending stack adjustment now that we have
             finished generating the sibling call sequence.  */

          pending_stack_adjust = save_pending_stack_adjust;
          stack_pointer_delta = save_stack_pointer_delta;

          /* Prepare arg structure for next iteration.  */
          for (i = 0 ; i < num_actuals ; i++)
            {
              args[i].value = 0;
              args[i].aligned_regs = 0;
              args[i].stack = 0;
            }

          sbitmap_free (stored_args_map);
        }
      else
        normal_call_insns = insns;
    }

  /* The function optimize_sibling_and_tail_recursive_calls doesn't
     handle CALL_PLACEHOLDERs inside other CALL_PLACEHOLDERs.  This
     can happen if the arguments to this function call an inline
     function who's expansion contains another CALL_PLACEHOLDER.

     If there are any C_Ps in any of these sequences, replace them
     with their normal call. */

  for (insn = normal_call_insns; insn; insn = NEXT_INSN (insn))
    if (GET_CODE (insn) == CALL_INSN
        && GET_CODE (PATTERN (insn)) == CALL_PLACEHOLDER)
      replace_call_placeholder (insn, sibcall_use_normal);

  for (insn = tail_call_insns; insn; insn = NEXT_INSN (insn))
    if (GET_CODE (insn) == CALL_INSN
        && GET_CODE (PATTERN (insn)) == CALL_PLACEHOLDER)
      replace_call_placeholder (insn, sibcall_use_normal);

  for (insn = tail_recursion_insns; insn; insn = NEXT_INSN (insn))
    if (GET_CODE (insn) == CALL_INSN
        && GET_CODE (PATTERN (insn)) == CALL_PLACEHOLDER)
      replace_call_placeholder (insn, sibcall_use_normal);

  /* If this was a potential tail recursion site, then emit a
     CALL_PLACEHOLDER with the normal and the tail recursion streams.
     One of them will be selected later.  */
  if (tail_recursion_insns || tail_call_insns)
    {
      /* The tail recursion label must be kept around.  We could expose
         its use in the CALL_PLACEHOLDER, but that creates unwanted edges
         and makes determining true tail recursion sites difficult.

         So we set LABEL_PRESERVE_P here, then clear it when we select
         one of the call sequences after rtl generation is complete.  */
      if (tail_recursion_insns)
        LABEL_PRESERVE_P (tail_recursion_label) = 1;
      emit_call_insn (gen_rtx_CALL_PLACEHOLDER (VOIDmode, normal_call_insns,
                                                tail_call_insns,
                                                tail_recursion_insns,
                                                tail_recursion_label));
    }
  else
    emit_insns (normal_call_insns);

  currently_expanding_call--;

  return target;
}
\f
/* Returns nonzero if FUN is the symbol for a library function which can
   not throw.  */

static int
libfunc_nothrow (fun)
     rtx fun;
{
  if (fun == throw_libfunc
      || fun == rethrow_libfunc
      || fun == sjthrow_libfunc
      || fun == sjpopnthrow_libfunc)
    return 0;

  return 1;
}
\f
/* Output a library call to function FUN (a SYMBOL_REF rtx).
   The RETVAL parameter specifies whether return value needs to be saved, other 
   parameters are documented in the emit_library_call function bellow.  */
static rtx
emit_library_call_value_1 (retval, orgfun, value, fn_type, outmode, nargs, p)
     int retval;
     rtx orgfun;
     rtx value;
     int fn_type;
     enum machine_mode outmode;
     int nargs;
     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;
  struct args_size alignment_pad;
  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; rtx save_area; };
  struct arg *argvec;
  int old_inhibit_defer_pop = inhibit_defer_pop;
  rtx call_fusage = 0;
  rtx mem_value = 0;
  rtx valreg;
  int pcc_struct_value = 0;
  int struct_value_size = 0;
  int flags = 0;
  int reg_parm_stack_space = 0;
  int needed;

#ifdef 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 = 0;
  rtx save_area = 0;            /* Place that it is saved */
#endif

  /* Size of the stack reserved for parameter registers.  */
  int initial_highest_arg_in_use = highest_outgoing_arg_in_use;
  char *initial_stack_usage_map = stack_usage_map;

#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 ((tree) 0);
#endif
#endif

  if (fn_type == 1)
    flags |= ECF_CONST;
  else if (fn_type == 2)
    flags |= ECF_PURE;
  fun = orgfun;

  if (libfunc_nothrow (fun))
    flags |= ECF_NOTHROW;

#ifdef PREFERRED_STACK_BOUNDARY
  /* Ensure current function's preferred stack boundary is at least
     what we need.  */
  if (cfun->preferred_stack_boundary < PREFERRED_STACK_BOUNDARY)
    cfun->preferred_stack_boundary = PREFERRED_STACK_BOUNDARY;
#endif

  /* If this kind of value comes back in memory,
     decide where in memory it should come back.  */
  if (outmode != VOIDmode && 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, 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.  */
      flags &= ~(ECF_CONST | ECF_PURE);
    }

  /* ??? 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));
  bzero ((char *) argvec, (nargs + 1) * sizeof (struct arg));

  INIT_CUMULATIVE_ARGS (args_so_far, NULL_TREE, fun, 0);

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

  count = 0;

  /* Now we are about to start emitting insns that can be deleted
     if a libcall is deleted.  */
  if (flags & (ECF_CONST | ECF_PURE))
    start_sequence ();

  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,
#ifdef STACK_PARMS_IN_REG_PARM_AREA
                           1,
#else
                           argvec[count].reg != 0,
#endif
                           NULL_TREE, &args_size, &argvec[count].offset,
                           &argvec[count].size, &alignment_pad);


      if (argvec[count].reg == 0 || argvec[count].partial != 0
          || reg_parm_stack_space > 0)
        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 = 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);

#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,
#ifdef STACK_PARMS_IN_REG_PARM_AREA
                           1,
#else
                           argvec[count].reg != 0,
#endif
                           NULL_TREE, &args_size, &argvec[count].offset,
                           &argvec[count].size, &alignment_pad);

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

      if (reg_parm_stack_space == 0 && argvec[count].partial)
        argvec[count].size.constant -= argvec[count].partial * UNITS_PER_WORD;

      if (argvec[count].reg == 0 || argvec[count].partial != 0
          || reg_parm_stack_space > 0)
        args_size.constant += argvec[count].size.constant;

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

#ifdef FINAL_REG_PARM_STACK_SPACE
  reg_parm_stack_space = FINAL_REG_PARM_STACK_SPACE (args_size.constant,
                                                     args_size.var);
#endif
  /* If this machine requires an external definition for library
     functions, write one out.  */
  assemble_external_libcall (fun);

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

  args_size.constant = MAX (args_size.constant,
                            reg_parm_stack_space);

#ifndef OUTGOING_REG_PARM_STACK_SPACE
  args_size.constant -= reg_parm_stack_space;
#endif

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

  if (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.

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

      needed = args_size.constant;

#ifndef 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
    {
      if (!PUSH_ARGS)
        argblock = push_block (GEN_INT (args_size.constant), 0, 0);
    }

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

  if (PUSH_ARGS_REVERSED)
    {
      inc = -1;
      argnum = nargs - 1;
    }
  else
    {
      inc = 1;
      argnum = 0;
    }

#ifdef REG_PARM_STACK_SPACE
  if (ACCUMULATE_OUTGOING_ARGS)
    {
      /* 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 (count = 0; count < reg_parm_stack_space + 1; count++)
#else
      for (count = 0; count < reg_parm_stack_space; count++)
#endif
        {
          if (count >=  highest_outgoing_arg_in_use
              || stack_usage_map[count] == 0)
            continue;

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

          high_to_save = count;
        }

      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;

#ifdef ARGS_GROW_DOWNWARD
          stack_area = gen_rtx_MEM (save_mode,
                                    memory_address (save_mode,
                                                    plus_constant (argblock,
                                                                   - high_to_save)));
#else
          stack_area = gen_rtx_MEM (save_mode,
                                    memory_address (save_mode,
                                                    plus_constant (argblock,
                                                                   low_to_save)));
#endif
          if (save_mode == BLKmode)
            {
              save_area = assign_stack_temp (BLKmode, num_to_save, 0);
              emit_block_move (validize_mem (save_area), stack_area,
                               GEN_INT (num_to_save), PARM_BOUNDARY);
            }
          else
            {
              save_area = gen_reg_rtx (save_mode);
              emit_move_insn (save_area, stack_area);
            }
        }
    }
#endif
          
  /* Push the args that need to be pushed.  */

  /* ARGNUM indexes the ARGVEC array in the order in which the arguments
     are 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;
      int lower_bound = 0, upper_bound = 0, i;

      if (! (reg != 0 && partial == 0))
        {
          if (ACCUMULATE_OUTGOING_ARGS)
            {
              /* If this is being stored into a pre-allocated, fixed-size,
                 stack area, save any previous data at that location.  */

#ifdef ARGS_GROW_DOWNWARD
              /* stack_slot is negative, but we want to index stack_usage_map
                 with positive values.  */
              upper_bound = -argvec[argnum].offset.constant + 1;
              lower_bound = upper_bound - argvec[argnum].size.constant;
#else
              lower_bound = argvec[argnum].offset.constant;
              upper_bound = lower_bound + argvec[argnum].size.constant;
#endif

              for (i = lower_bound; i < upper_bound; i++)
                if (stack_usage_map[i]
                    /* Don't store things in the fixed argument area at this
                       point; it has already been saved.  */
                    && i > reg_parm_stack_space)
                  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 (argvec[argnum].size.constant
                                     * BITS_PER_UNIT,
                                     MODE_INT, 1);
                  rtx stack_area
                    = gen_rtx_MEM
                      (save_mode,
                       memory_address
                       (save_mode,
                        plus_constant (argblock,
                                       argvec[argnum].offset.constant)));
                  argvec[argnum].save_area = gen_reg_rtx (save_mode);

                  emit_move_insn (argvec[argnum].save_area, stack_area);
                }
            }

          emit_push_insn (val, mode, NULL_TREE, NULL_RTX, 0, partial, reg, 0,
                          argblock, GEN_INT (argvec[argnum].offset.constant),
                          reg_parm_stack_space, ARGS_SIZE_RTX (alignment_pad));

          /* Now mark the segment we just used.  */
          if (ACCUMULATE_OUTGOING_ARGS)
            for (i = lower_bound; i < upper_bound; i++)
              stack_usage_map[i] = 1;

          NO_DEFER_POP;
        }
    }

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

  if (PUSH_ARGS_REVERSED)
    argnum = nargs - 1;
  else
    argnum = 0;

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

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

  /* ARGNUM indexes the ARGVEC array in the order in which the arguments
     are to be pushed.  */
  for (count = 0; count < nargs; count++, argnum += inc)
    {
      register rtx val = argvec[argnum].value;
      rtx reg = argvec[argnum].reg;
      int partial = argvec[argnum].partial;

      /* Handle calls that pass values in multiple non-contiguous
         locations.  The PA64 has examples of this for library calls.  */
      if (reg != 0 && GET_CODE (reg) == PARALLEL)
        emit_group_load (reg, val,
                         GET_MODE_SIZE (GET_MODE (val)),
                         GET_MODE_ALIGNMENT (GET_MODE (val)));
      else if (reg != 0 && partial == 0)
        emit_move_insn (reg, val);

      NO_DEFER_POP;
    }

  /* Any regs containing parms remain in use through the call.  */
  for (count = 0; count < nargs; count++)
    {
      rtx reg = argvec[count].reg;
      if (reg != 0 && GET_CODE (reg) == PARALLEL)
        use_group_regs (&call_fusage, reg);
      else if (reg != 0)
        use_reg (&call_fusage, 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;
  valreg = (mem_value == 0 && outmode != VOIDmode
            ? hard_libcall_value (outmode) : NULL_RTX);

#ifdef PREFERRED_STACK_BOUNDARY
  /* Stack must be properly aligned now.  */
  if (stack_pointer_delta & (PREFERRED_STACK_BOUNDARY / BITS_PER_UNIT - 1))
    abort();
#endif

  /* We pass the old value of inhibit_defer_pop + 1 to emit_call_1, which
     will set inhibit_defer_pop to that value.  */
  /* The return type is needed to decide how many bytes the function pops.
     Signedness plays no role in that, so for simplicity, we pretend it's
     always signed.  We also assume that the list of arguments passed has
     no impact, so we pretend it is unknown.  */

  emit_call_1 (fun, 
               get_identifier (XSTR (orgfun, 0)),
               build_function_type (outmode == VOIDmode ? void_type_node
                                    : type_for_mode (outmode, 0), NULL_TREE),
               original_args_size.constant, args_size.constant,
               struct_value_size,
               FUNCTION_ARG (args_so_far, VOIDmode, void_type_node, 1),
               valreg,
               old_inhibit_defer_pop + 1, call_fusage, flags);

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

  /* 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.  Disable for PARALLEL return values, because
     we have no way to move such values into a pseudo register.  */
  if ((flags & (ECF_CONST | ECF_PURE))
      && valreg != 0 && GET_CODE (valreg) != PARALLEL)
    {
      rtx note = 0;
      rtx temp = gen_reg_rtx (GET_MODE (valreg));
      rtx insns;
      int i;

      /* Construct an "equal form" for the value which mentions all the
         arguments in order as well as the function name.  */
      for (i = 0; i < nargs; i++)
        note = gen_rtx_EXPR_LIST (VOIDmode, argvec[i].value, note);
      note = gen_rtx_EXPR_LIST (VOIDmode, fun, note);

      insns = get_insns ();
      end_sequence ();

      if (flags & ECF_PURE)
        note = gen_rtx_EXPR_LIST (VOIDmode,
           gen_rtx_USE (VOIDmode,
                        gen_rtx_MEM (BLKmode,
                                     gen_rtx_SCRATCH (VOIDmode))), note);

      emit_libcall_block (insns, temp, valreg, note);

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

      end_sequence ();
      emit_insns (insns);
    }
  pop_temp_slots ();

  /* Copy the value to the right place.  */
  if (outmode != VOIDmode && retval)
    {
      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);
    }

  if (ACCUMULATE_OUTGOING_ARGS)
    {
#ifdef REG_PARM_STACK_SPACE
      if (save_area)
        {
          enum machine_mode save_mode = GET_MODE (save_area);
#ifdef ARGS_GROW_DOWNWARD
          rtx stack_area
            = gen_rtx_MEM (save_mode,
                           memory_address (save_mode,
                                           plus_constant (argblock,
                                                          - high_to_save)));
#else
          rtx stack_area
            = gen_rtx_MEM (save_mode,
                           memory_address (save_mode,
                                           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);
        }
#endif
              
      /* If we saved any argument areas, restore them.  */
      for (count = 0; count < nargs; count++)
        if (argvec[count].save_area)
          {
            enum machine_mode save_mode = GET_MODE (argvec[count].save_area);
            rtx stack_area
              = gen_rtx_MEM (save_mode,
                             memory_address
                             (save_mode,
                              plus_constant (argblock,
                                             argvec[count].offset.constant)));

            emit_move_insn (stack_area, argvec[count].save_area);
          }

      highest_outgoing_arg_in_use = initial_highest_arg_in_use;
      stack_usage_map = initial_stack_usage_map;
    }

  return value;

}
\f
/* 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.

   FN_TYPE will is zero for `normal' calls, one for `const' calls, wich
   which will be enclosed in REG_LIBCALL/REG_RETVAL notes and two for `pure'
   calls, that are handled like `const' calls with extra
   (use (memory (scratch)).  */

void
emit_library_call VPARAMS((rtx orgfun, int fn_type, enum machine_mode outmode,
                           int nargs, ...))
{
#ifndef ANSI_PROTOTYPES
  rtx orgfun;
  int fn_type;
  enum machine_mode outmode;
  int nargs;
#endif
  va_list p;

  VA_START (p, nargs);

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

  emit_library_call_value_1 (0, orgfun, NULL_RTX, fn_type, outmode, nargs, p);

  va_end (p);
}
\f
/* 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 VPARAMS((rtx orgfun, rtx value, int fn_type,
                                 enum machine_mode outmode, int nargs, ...))
{
#ifndef ANSI_PROTOTYPES
  rtx orgfun;
  rtx value;
  int fn_type;
  enum machine_mode outmode;
  int nargs;
#endif
  va_list p;

  VA_START (p, nargs);

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

  value = emit_library_call_value_1 (1, orgfun, value, fn_type, outmode, nargs, p);

  va_end (p);

  return value;
}
\f
#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
\f
/* 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, flags, variable_size,
               reg_parm_stack_space)
     struct arg_data *arg;
     rtx argblock;
     int flags;
     int variable_size ATTRIBUTE_UNUSED;
     int reg_parm_stack_space;
{
  register tree pval = arg->tree_value;
  rtx reg = 0;
  int partial = 0;
  int used = 0;
  int i, lower_bound = 0, upper_bound = 0;

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

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

  if (ACCUMULATE_OUTGOING_ARGS && !(flags & ECF_SIBCALL))
    {
      /* 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
            upper_bound = 0;

          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]
                /* Don't store things in the fixed argument area at this point;
                   it has already been saved.  */
                && i > reg_parm_stack_space)
              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, 0);
                  MEM_SET_IN_STRUCT_P (arg->save_area,
                                       AGGREGATE_TYPE_P (TREE_TYPE
                                                         (arg->tree_value))); 
                  preserve_temp_slots (arg->save_area);
                  emit_block_move (validize_mem (arg->save_area), stack_area,
                                   GEN_INT (arg->size.constant),
                                   PARM_BOUNDARY);
                }
              else
                {
                  arg->save_area = gen_reg_rtx (save_mode);
                  emit_move_insn (arg->save_area, stack_area);
                }
            }
        }
      /* Now that we have saved any slots that will be overwritten by this
         store, mark all slots this store will use.  We must do this before
         we actually expand the argument since the expansion itself may
         trigger library calls which might need to use the same stack slot.  */
      if (argblock && ! variable_size && arg->stack)
        for (i = lower_bound; i < upper_bound; i++)
          stack_usage_map[i] = 1;
    }

  /* 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 ();

  /* If this arg needs special alignment, don't load the registers
     here.  */
  if (arg->n_aligned_regs != 0)
    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)
    {
      /* 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++;

      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);

      if (arg->pass_on_stack)
        stack_arg_under_construction--;
    }

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

  if (arg->value == arg->stack)
    {
      /* If the value is already in the stack slot, we are done.  */
      if (current_function_check_memory_usage && GET_CODE (arg->stack) == MEM)
        {
          emit_library_call (chkr_set_right_libfunc, 1, VOIDmode, 3,
                             XEXP (arg->stack, 0), Pmode, 
                             ARGS_SIZE_RTX (arg->size),
                             TYPE_MODE (sizetype),
                             GEN_INT (MEMORY_USE_RW),
                             TYPE_MODE (integer_type_node));
        }
    }
  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), reg_parm_stack_space,
                      ARGS_SIZE_RTX (arg->alignment_pad));
    }
  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)), partial, reg, excess,
                      argblock, ARGS_SIZE_RTX (arg->offset),
                      reg_parm_stack_space,
                      ARGS_SIZE_RTX (arg->alignment_pad));
    }


  /* 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 ();
}