/* Expands front end tree to back end RTL for GNU C-Compiler
   Copyright (C) 1987,1988 Free Software Foundation, Inc.

This file is part of GNU CC.

GNU CC is distributed in the hope that it will be useful,
but WITHOUT ANY WARRANTY.  No author or distributor
accepts responsibility to anyone for the consequences of using it
or for whether it serves any particular purpose or works at all,
unless he says so in writing.  Refer to the GNU CC General Public
License for full details.

Everyone is granted permission to copy, modify and redistribute
GNU CC, but only under the conditions described in the
GNU CC General Public License.   A copy of this license is
supposed to have been given to you along with GNU CC so you
can know your rights and responsibilities.  It should be in a
file named COPYING.  Among other things, the copyright notice
and this notice must be preserved on all copies.  */


/* This file handles the generation of rtl code from tree structure
   above the level of expressions, using subroutines in exp*.c and emit-rtl.c.
   It also creates the rtl expressions for parameters and auto variables
   and has full responsibility for allocating stack slots.

   The functions whose names start with `expand_' are called by the
   parser to generate RTL instructions for various kinds of constructs.

   Some control and binding constructs require calling several such
   functions at different times.  For example, a simple if-then
   is expanded by calling `expand_start_cond' (with the condition-expression
   as argument) before parsing the then-clause and calling `expand_end_cond'
   after parsing the then-clause.

   `expand_function_start' is called at the beginning of a function,
   before the function body is parsed, and `expand_function_end' is
   called after parsing the body.

   Call `assign_stack_local' to allocate a stack slot for a local variable.
   This is usually done during the RTL generation for the function body,
   but it can also be done in the reload pass when a pseudo-register does
   not get a hard register.

   Call `put_var_into_stack' when you learn, belatedly, that a variable
   previously given a pseudo-register must in fact go in the stack.
   This function changes the DECL_RTL to be a stack slot instead of a reg
   then scans all the RTL instructions so far generated to correct them.  */

#include "config.h"

#include <stdio.h>

#include "rtl.h"
#include "tree.h"
#include "flags.h"
#include "insn-flags.h"
#include "insn-config.h"
#include "expr.h"
#include "regs.h"

#define MAX(x,y) (((x) > (y)) ? (x) : (y))
#define MIN(x,y) (((x) < (y)) ? (x) : (y))

/* Nonzero if function being compiled pops its args on return.
   May affect compilation of return insn or of function epilogue.  */

int current_function_pops_args;

/* Nonzero if function being compiled needs to be given an address
   where the value should be stored.  */

int current_function_returns_struct;

/* Nonzero if function being compiled needs to be passed a static chain.  */

int current_function_needs_context;

/* Nonzero if function being compiled can call setjmp.  */

int current_function_calls_setjmp;

/* If function's args have a fixed size, this is that size, in bytes.
   Otherwise, it is -1.
   May affect compilation of return insn or of function epilogue.  */

int current_function_args_size;

/* # bytes the prologue should push and pretend that the caller pushed them.
   The prologue must do this, but only if parms can be passed in registers.  */

int current_function_pretend_args_size;

/* Name of function now being compiled.  */

char *current_function_name;

/* Label that will go on function epilogue.
   Jumping to this label serves as a "return" instruction
   on machines which require execution of the epilogue on all returns.  */

rtx return_label;

/* List (chain of EXPR_LISTs) of pseudo-regs of SAVE_EXPRs.
   So we can mark them all live at the end of the function, if nonopt.  */
rtx save_expr_regs;

/* Insn after which register parms and SAVE_EXPRs are born, if nonopt.  */
static rtx parm_birth_insn;

/* The FUNCTION_DECL node for the function being compiled.  */

static tree this_function;

/* Offset to end of allocated area of stack frame.
   If stack grows down, this is the address of the last stack slot allocated.
   If stack grows up, this is the address for the next slot.  */
static int frame_offset;

/* Nonzero if a stack slot has been generated whose address is not
   actually valid.  It means that the generated rtl must all be scanned
   to detect and correct the invalid addresses where they occur.  */
static int invalid_stack_slot;

/* Label to jump back to for tail recursion, or 0 if we have
   not yet needed one for this function.  */
static rtx tail_recursion_label;

/* Place after which to insert the tail_recursion_label if we need one.  */
static rtx tail_recursion_reentry;

/* Each time we expand an expression-statement,
   record the expr's type and its RTL value here.  */

static tree last_expr_type;
static rtx last_expr_value;

/* Chain of all RTL_EXPRs that have insns in them.  */
static tree rtl_expr_chain;

/* Last insn of those whose job was to put parms into their nominal homes.  */
static rtx last_parm_insn;

static void expand_goto_internal ();
static int expand_fixup ();
static void fixup_gotos ();
static void expand_cleanups ();
static void fixup_cleanups ();
static void expand_null_return_1 ();
static int tail_recursion_args ();
static void fixup_stack_slots ();
static rtx fixup_stack_1 ();
static rtx fixup_memory_subreg ();
static void fixup_var_refs ();
static void fixup_var_refs_insns ();
static rtx fixup_var_refs_1 ();
static rtx parm_stack_loc ();
static void optimize_bit_field ();
void do_jump_if_equal ();

/* Stack of control and binding constructs we are currently inside.

   These constructs begin when you call `expand_start_WHATEVER'
   and end when you call `expand_end_WHATEVER'.  This stack records
   info about how the construct began that tells the end-function
   what to do.  It also may provide information about the construct
   to alter the behavior of other constructs within the body.
   For example, they may affect the behavior of C `break' and `continue'.

   Each construct gets one `struct nesting' object.
   All of these objects are chained through the `all' field.
   `nesting_stack' points to the first object (innermost construct).
   The position of an entry on `nesting_stack' is in its `depth' field.

   Each type of construct has its own individual stack.
   For example, loops have `loop_stack'.  Each object points to the
   next object of the same type through the `next' field.

   Some constructs are visible to `break' exit-statements and others
   are not.  Which constructs are visible depends on the language.
   Therefore, the data structure allows each construct to be visible
   or not, according to the args given when the construct is started.
   The construct is visible if the `exit_label' field is non-null.
   In that case, the value should be a CODE_LABEL rtx.  */

struct nesting
{
  struct nesting *all;
  struct nesting *next;
  int depth;
  rtx exit_label;
  union
    {
      /* For conds (if-then and if-then-else statements).  */
      struct
	{
	  /* Label on the else-part, if any, else 0.  */
	  rtx else_label;
	  /* Label at the end of the whole construct.  */
	  rtx after_label;
	} cond;
      /* For loops.  */
      struct
	{
	  /* Label at the top of the loop; place to loop back to.  */
	  rtx start_label;
	  /* Label at the end of the whole construct.  */
	  rtx end_label;
	  /* Label for `continue' statement to jump to;
	     this is in front of the stepper of the loop.  */
	  rtx continue_label;
	} loop;
      /* For variable binding contours.  */
      struct
	{
	  /* Nonzero => value to restore stack to on exit.  */
	  rtx stack_level;
	  /* The NOTE that starts this contour.
	     Used by expand_goto to check whether the destination
	     is within each contour or not.  */
	  rtx first_insn;
	  /* Innermost containing binding contour that has a stack level.  */
	  struct nesting *innermost_stack_block;
	  /* List of cleanups to be run on exit from this contour.
	     This is a list of expressions to be evaluated.
	     The TREE_PURPOSE of each link is the ..._DECL node
	     which the cleanup pertains to.  */
	  tree cleanups;
	  /* Chain of labels defined inside this binding contour.
	     For contours that have stack levels or cleanups.  */
	  struct label_chain *label_chain;
	} block;
      /* For switch (C) or case (Pascal) statements,
	 and also for dummies (see `expand_start_case_dummy').  */
      struct
	{
	  /* The insn after which the case dispatch should finally
	     be emitted.  Zero for a dummy.  */
	  rtx start;
	  /* A list of the case-values and their labels.
	     A chain of TREE_LIST nodes with the value to test for
	     (a constant node) in the TREE_PURPOSE and the
	     label (a LABEL_DECL) in the TREE_VALUE.  */
	  tree case_list;
	  /* The expression to be dispatched on.  */
	  tree index_expr;
	  /* Type that INDEX_EXPR should be converted to.  */
	  tree nominal_type;
	  /* Nonzero: a `default' has been seen.  */
	  short has_default;
	} case_stmt;
    } data;
};

/* Chain of all pending binding contours.  */
struct nesting *block_stack;

/* Chain of all pending binding contours that restore stack levels
   or have cleanups.  */
struct nesting *stack_block_stack;

/* Chain of all pending conditional statements.  */
struct nesting *cond_stack;

/* Chain of all pending loops.  */
struct nesting *loop_stack;

/* Chain of all pending case or switch statements.  */
struct nesting *case_stack;

/* Separate chain including all of the above,
   chained through the `all' field.  */
struct nesting *nesting_stack;

/* Number of entries on nesting_stack now.  */
int nesting_depth;

/* Pop one of the sub-stacks, such as `loop_stack' or `cond_stack';
   and pop off `nesting_stack' down to the same level.  */

#define POPSTACK(STACK)					\
do { int initial_depth = nesting_stack->depth;		\
     do { struct nesting *this = STACK;			\
	  STACK = this->next;				\
	  nesting_stack = this->all;			\
	  nesting_depth = this->depth;			\
	  free (this); }				\
     while (nesting_depth > initial_depth); } while (0)

/* Return the rtx-label that corresponds to a LABEL_DECL,
   creating it if necessary.  */

static rtx
label_rtx (label)
     tree label;
{
  if (TREE_CODE (label) != LABEL_DECL)
    abort ();

  if (DECL_RTL (label))
    return DECL_RTL (label);

  return DECL_RTL (label) = gen_label_rtx ();
}

/* Add an unconditional jump to LABEL as the next sequential instruction.  */

void
emit_jump (label)
     rtx label;
{
  do_pending_stack_adjust ();
  emit_jump_insn (gen_jump (label));
  emit_barrier ();
}

/* Handle goto statements and the labels that they can go to.  */

/* In some cases it is impossible to generate code for a forward goto 
   until the label definition is seen.  This happens when it may be necessary
   for the goto to reset the stack pointer: we don't yet know how to do that.
   So expand_goto puts an entry on this fixup list.
   Each time a binding contour that resets the stack is exited,
   we check each fixup.
   If the target label has now been defined, we can insert the proper code.  */

struct goto_fixup
{
  /* Points to following fixup.  */
  struct goto_fixup *next;
  /* Points to the insn before the jump insn.
     If more code must be inserted, it goes after this insn.  */
  rtx before_jump;
  /* The LABEL_DECL that this jump is jumping to, or 0
     for break, continue or return.  */
  tree target;
  /* The CODE_LABEL rtx that this is jumping to.  */
  rtx target_rtl;
  /* The outermost stack level that should be restored for this jump.
     Each time a binding contour that resets the stack is exited,
     if the target label is *not* yet defined, this slot is updated.  */
  rtx stack_level;
  /* List of lists of cleanup expressions to be run by this goto.  */
  tree cleanup_list_list;
};

static struct goto_fixup *goto_fixup_chain;

/* Within any binding contour that must restore a stack level,
   all labels are recorded with a chain of these structures.  */

struct label_chain
{
  /* Points to following fixup.  */
  struct label_chain *next;
  tree label;
};

/* Specify the location in the RTL code of a label BODY,
   which is a LABEL_DECL tree node.

   This is used for the kind of label that the user can jump to with a
   goto statement, and for alternatives of a switch or case statement.
   RTL labels generated for loops and conditionals don't go through here;
   they are generated directly at the RTL level, by other functions below.

   Note that this has nothing to do with defining label *names*.
   Languages vary in how they do that and what that even means.  */

void
expand_label (body)
     tree body;
{
  struct label_chain *p;

  do_pending_stack_adjust ();
  emit_label (label_rtx (body));

  if (stack_block_stack != 0)
    {
      p = (struct label_chain *) oballoc (sizeof (struct label_chain));
      p->next = stack_block_stack->data.block.label_chain;
      stack_block_stack->data.block.label_chain = p;
      p->label = body;
    }
}

/* Generate RTL code for a `goto' statement with target label BODY.
   BODY should be a LABEL_DECL tree node that was or will later be
   defined with `expand_label'.  */

void
expand_goto (body)
     tree body;
{
  expand_goto_internal (body, label_rtx (body), 0);
}

/* Generate RTL code for a `goto' statement with target label BODY.
   LABEL should be a LABEL_REF.
   LAST_INSN, if non-0, is the rtx we should consider as the last
   insn emitted (for the purposes of cleaning up a return).  */

static void
expand_goto_internal (body, label, last_insn)
     tree body;
     rtx label;
     rtx last_insn;
{
  struct nesting *block;
  rtx stack_level = 0;

  if (GET_CODE (label) != CODE_LABEL)
    abort ();

  /* If label has already been defined, we can tell now
     whether and how we must alter the stack level.  */

  if (PREV_INSN (label) != 0)
    {
      /* Find the outermost pending block that contains the label.
	 (Check containment by comparing insn-uids.)
	 Then restore the outermost stack level within that block.  */
      for (block = block_stack; block; block = block->next)
	{
	  if (INSN_UID (block->data.block.first_insn) < INSN_UID (label))
	    break;
	  if (block->data.block.stack_level != 0)
	    stack_level = block->data.block.stack_level;
	  /* Execute the cleanups for blocks we are exiting.  */
	  if (block->data.block.cleanups != 0)
	    expand_cleanups (block->data.block.cleanups, 0);
	}

      if (stack_level)
	emit_move_insn (stack_pointer_rtx, stack_level);

      if (body != 0 && TREE_PACKED (body))
	error ("goto \"%s\" invalidly jumps into binding contour",
	       IDENTIFIER_POINTER (DECL_NAME (body)));
    }
  /* Label not yet defined: may need to put this goto
     on the fixup list.  */
  else if (! expand_fixup (body, label, last_insn))
    /* No fixup needed.  Record that the label is the target
       of at least one goto that has no fixup.  */
    if (body != 0)
      TREE_ADDRESSABLE (body) = 1;

  emit_jump (label);
}

/* Generate if necessary a fixup for a goto
   whose target label in tree structure (if any) is TREE_LABEL
   and whose target in rtl is RTL_LABEL.

   If LAST_INSN is nonzero, we pretend that the jump appears
   after insn LAST_INSN instead of at the current point in the insn stream.

   The fixup will be used later to insert insns at this point
   to restore the stack level as appropriate for the target label.

   Value is nonzero if a fixup is made.  */

static int
expand_fixup (tree_label, rtl_label, last_insn)
     tree tree_label;
     rtx rtl_label;
     rtx last_insn;
{
  struct nesting *block;
  /* Does any containing block have a stack level or cleanups?
     If not, no fixup is needed, and that is the normal case
     (the only case, for standard C).  */
  for (block = block_stack; block; block = block->next)
    if (block->data.block.stack_level != 0
	|| block->data.block.cleanups != 0)
      break;

  if (block)
    {
      /* Ok, a fixup is needed.  Add a fixup to the list of such.  */
      struct goto_fixup *fixup
	= (struct goto_fixup *) oballoc (sizeof (struct goto_fixup));
      /* In case an old stack level is restored, make sure that comes
	 after any pending stack adjust.  */
      do_pending_stack_adjust ();
      fixup->before_jump = last_insn ? last_insn : get_last_insn ();
      fixup->target = tree_label;
      fixup->target_rtl = rtl_label;
      fixup->stack_level = 0;
      fixup->cleanup_list_list = NULL_TREE;
      fixup->next = goto_fixup_chain;
      goto_fixup_chain = fixup;
    }

  return block != 0;
}

/* When exiting a binding contour, process all pending gotos requiring fixups.
   STACK_LEVEL is the rtx for the stack level to restore exiting this contour.
   CLEANUPS is a list of expressions to evaluate on exiting this contour.
   FIRST_INSN is the insn that begain this contour.

   Gotos that jump out of this contour must restore the
   stack level and do the cleanups before actually jumping.

   DONT_JUMP_IN nonzero means report error there is a jump into this
   contour from before the beginning of the contour.
   This is also done if STACK_LEVEL is nonzero.  */

static void
fixup_gotos (stack_level, cleanup_list, first_insn, dont_jump_in)
     rtx stack_level;
     tree cleanup_list;
     rtx first_insn;
     int dont_jump_in;
{
  register struct goto_fixup *f;

  for (f = goto_fixup_chain; f; f = f->next)
    {
      /* Test for a fixup that is inactive because it is already handled.  */
      if (f->before_jump == 0)
	;
      /* Has this fixup's target label been defined?
	 If so, we can finalize it.  */
      else if (PREV_INSN (f->target_rtl) != 0)
	{
	  /* If this fixup jumped into this contour from before the beginning
	     of this contour, report an error.  */
	  if (f->target != 0
	      && (dont_jump_in || stack_level)
	      && INSN_UID (first_insn) > INSN_UID (f->before_jump)
	      && ! TREE_ADDRESSABLE (f->target))
	    {
	      error_with_file_and_line (DECL_SOURCE_FILE (f->target),
					DECL_SOURCE_LINE (f->target),
					"label \"%s\" was used \
before containing binding contour",
					IDENTIFIER_POINTER (DECL_NAME (f->target)));
	      /* Prevent multiple errors for one label.  */
	      TREE_ADDRESSABLE (f->target) = 1;
	    }

	  /* Execute cleanups for blocks this jump exits.  */
	  if (f->cleanup_list_list)
	    fixup_cleanups (f->cleanup_list_list, &f->before_jump);

	  /* Restore stack level for the biggest contour that this
	     jump jumps out of.  */
	  if (f->stack_level)
	    emit_insn_after (gen_move_insn (stack_pointer_rtx, f->stack_level),
			     f->before_jump);
	  f->before_jump = 0;
	}
      /* Label has still not appeared.  If we are exiting a block with
	 a stack level to restore, mark this stack level as needing
	 restoration when the fixup is later finalized.  */
      else
	{
	  if (stack_level)
	    f->stack_level = stack_level;
	  if (cleanup_list)
	    f->cleanup_list_list
	      = chainon (f->cleanup_list_list,
			 build_tree_list (NULL, cleanup_list));
	}
    }
}

/* Generate RTL for an asm statement (explicit assembler code).
   BODY is a STRING_CST node containing the assembler code text.  */

void
expand_asm (body)
     tree body;
{
  emit_insn (gen_rtx (ASM_INPUT, VOIDmode,
		      TREE_STRING_POINTER (body)));
  last_expr_type = 0;
}

/* Generate RTL for an asm statement with arguments.
   STRING is the instruction template.
   OUTPUTS is a list of output arguments (lvalues); INPUTS a list of inputs.
   Each output or input has an expression in the TREE_VALUE and
   a constraint-string in the TREE_PURPOSE.
   CLOBBERS is a list of STRING_CST nodes each naming a hard register
   that is clobbered by this insn.

   Not all kinds of lvalue that may appear in OUTPUTS can be stored directly.
   Some elements of OUTPUTS may be replaced with trees representing temporary
   values.  The caller should copy those temporary values to the originally
   specified lvalues.

   VOL nonzero means the insn is volatile; don't optimize it.  */

void
expand_asm_operands (string, outputs, inputs, clobbers, vol)
     tree string, outputs, inputs, clobbers;
     int vol;
{
  rtvec argvec, constraints;
  rtx body;
  int ninputs = list_length (inputs);
  int noutputs = list_length (outputs);
  int nclobbers = list_length (clobbers);
  tree tail;
  int i;

  last_expr_type = 0;

  for (i = 0, tail = outputs; tail; tail = TREE_CHAIN (tail), i++)
    {
      tree val = TREE_VALUE (tail);

      /* If there's an erroneous arg, emit no insn.  */
      if (TREE_TYPE (val) == error_mark_node)
	return;

      /* If an output operand is not a variable or indirect ref,
	 create a SAVE_EXPR which is a pseudo-reg
	 to act as an intermediate temporary.
	 Make the asm insn write into that, then copy it to
	 the real output operand.  */

      if (TREE_CODE (val) != VAR_DECL
	  && TREE_CODE (val) != PARM_DECL
	  && TREE_CODE (val) != INDIRECT_REF)
	{
	  rtx reg = gen_reg_rtx (TYPE_MODE (TREE_TYPE (val)));
	  /* `build' isn't safe; it really expects args to be trees.  */
	  tree t = build_nt (SAVE_EXPR, val, reg);

	  save_expr_regs = gen_rtx (EXPR_LIST, VOIDmode, reg, save_expr_regs);
	  TREE_VALUE (tail) = t;
	  TREE_TYPE (t) = TREE_TYPE (val);
	}
    }

  if (ninputs + noutputs > MAX_RECOG_OPERANDS)
    {
      error ("more than %d operands in `asm'", MAX_RECOG_OPERANDS);
      return;
    }

  /* Make vectors for the expression-rtx and constraint strings.  */

  argvec = rtvec_alloc (ninputs);
  constraints = rtvec_alloc (ninputs);

  body = gen_rtx (ASM_OPERANDS, VOIDmode,
		  TREE_STRING_POINTER (string), "", 0, argvec, constraints);
  MEM_VOLATILE_P (body) = vol;

  /* Eval the inputs and put them into ARGVEC.
     Put their constraints into ASM_INPUTs and store in CONSTRAINTS.  */

  i = 0;
  for (tail = inputs; tail; tail = TREE_CHAIN (tail))
    {
      /* If there's an erroneous arg, emit no insn,
	 because the ASM_INPUT would get VOIDmode
	 and that could cause a crash in reload.  */
      if (TREE_TYPE (TREE_VALUE (tail)) == error_mark_node)
	return;
      if (TREE_PURPOSE (tail) == NULL_TREE)
	{
	  error ("hard register %s listed as input operand to `asm'",
		 TREE_STRING_POINTER (TREE_VALUE (tail)) );
	  return;
	}

      XVECEXP (body, 3, i)      /* argvec */
	= expand_expr (TREE_VALUE (tail), 0, VOIDmode, 0);
      XVECEXP (body, 4, i)      /* constraints */
	= gen_rtx (ASM_INPUT, TYPE_MODE (TREE_TYPE (TREE_VALUE (tail))),
		   TREE_STRING_POINTER (TREE_PURPOSE (tail)));
      i++;
    }

  /* Now, for each output, construct an rtx
     (set OUTPUT (asm_operands INSN OUTPUTNUMBER OUTPUTCONSTRAINT
			       ARGVEC CONSTRAINTS))
     If there is more than one, put them inside a PARALLEL.  */

  if (noutputs == 1 && nclobbers == 0)
    {
      tree val = TREE_VALUE (outputs);

      XSTR (body, 1) = TREE_STRING_POINTER (TREE_PURPOSE (outputs));
      emit_insn (gen_rtx (SET, VOIDmode,
			  expand_expr (val, 0, VOIDmode, 0),
			  body));
    }
  else if (noutputs == 0 && nclobbers == 0)
    {
      /* No output operands: put in a raw ASM_OPERANDS rtx.  */
      emit_insn (body);
    }
  else
    {
      rtx obody = body;
      int num = noutputs;
      if (num == 0) num = 1;
      body = gen_rtx (PARALLEL, VOIDmode, rtvec_alloc (num + nclobbers));

      /* For each output operand, store a SET.  */

      for (i = 0, tail = outputs; tail; tail = TREE_CHAIN (tail), i++)
	{
	  tree val = TREE_VALUE (tail);

	  XVECEXP (body, 0, i)
	    = gen_rtx (SET, VOIDmode,
		       expand_expr (val, 0, VOIDmode, 0),
		       gen_rtx (ASM_OPERANDS, VOIDmode,
				TREE_STRING_POINTER (string),
				TREE_STRING_POINTER (TREE_PURPOSE (tail)),
				i, argvec, constraints));
	  MEM_VOLATILE_P (SET_SRC (XVECEXP (body, 0, i))) = vol;
	}

      /* If there are no outputs (but there are some clobbers)
	 store the bare ASM_OPERANDS into the PARALLEL.  */

      if (i == 0)
	XVECEXP (body, 0, i++) = obody;

      /* Store (clobber REG) for each clobbered register specified.  */

      for (tail = clobbers; tail; tail = TREE_CHAIN (tail), i++)
	{
	  int j;
	  char *regname = TREE_STRING_POINTER (TREE_VALUE (tail));
	  extern char *reg_names[];
	      
	  for (j = 0; j < FIRST_PSEUDO_REGISTER; j++)
	    if (!strcmp (regname, reg_names[j]))
	      break;
	      
	  if (j == FIRST_PSEUDO_REGISTER)
	    {
	      error ("unknown register name %s in `asm'", regname);
	      return;
	    }

	  /* Use QImode since that's guaranteed to clobber just one reg.  */
	  XVECEXP (body, 0, i)
	    = gen_rtx (CLOBBER, VOIDmode, gen_rtx (REG, QImode, j));
	}

      emit_insn (body);
    }
  last_expr_type = 0;
}

/* Nonzero if within a ({...}) grouping, in which case we must
   always compute a value for each expr-stmt in case it is the last one.  */

int expr_stmts_for_value;

/* Generate RTL to evaluate the expression EXP
   and remember it in case this is the VALUE in a ({... VALUE; }) constr.  */

void
expand_expr_stmt (exp)
     tree exp;
{
  last_expr_type = TREE_TYPE (exp);
  last_expr_value = expand_expr (exp, expr_stmts_for_value ? 0 : const0_rtx,
				 VOIDmode, 0);
  emit_queue ();
}

/* Clear out the memory of the last expression evaluated.  */

void
clear_last_expr ()
{
  last_expr_type = 0;
}

/* Begin a statement which will return a value.
   Return the RTL_EXPR for this statement expr.
   The caller must save that value and pass it to expand_end_stmt_expr.  */

tree
expand_start_stmt_expr ()
{
  rtx save = start_sequence ();
  /* Make the RTL_EXPR node temporary, not momentary,
     so that rtl_expr_chain doesn't become garbage.  */
  int momentary = suspend_momentary ();
  tree t = make_node (RTL_EXPR);
  resume_momentary (momentary);
  RTL_EXPR_RTL (t) = save;
  expr_stmts_for_value++;
  return t;
}

/* Restore the previous state at the end of a statement that returns a value.
   Returns a tree node representing the statement's value and the
   insns to compute the value.

   The nodes of that expression have been freed by now, so we cannot use them.
   But we don't want to do that anyway; the expression has already been
   evaluated and now we just want to use the value.  So generate a RTL_EXPR
   with the proper type and RTL value.

   If the last substatement was not an expression,
   return something with type `void'.  */

tree
expand_end_stmt_expr (t)
     tree t;
{
  rtx saved = RTL_EXPR_RTL (t);

  if (last_expr_type == 0)
    {
      last_expr_type = void_type_node;
      last_expr_value = const0_rtx;
    }
  TREE_TYPE (t) = last_expr_type;
  RTL_EXPR_RTL (t) = last_expr_value;
  RTL_EXPR_SEQUENCE (t) = get_insns ();

  rtl_expr_chain = tree_cons (NULL_TREE, t, rtl_expr_chain);

  end_sequence (saved);

  /* Don't consider deleting this expr or containing exprs at tree level.  */
  TREE_VOLATILE (t) = 1;
  /* Propagate volatility of the actual RTL expr.  */
  TREE_THIS_VOLATILE (t) = volatile_refs_p (last_expr_value);

  last_expr_type = 0;
  expr_stmts_for_value--;

  return t;
}

/* Generate RTL for the start of an if-then.  COND is the expression
   whose truth should be tested.

   If EXITFLAG is nonzero, this conditional is visible to
   `exit_something'.  */

void
expand_start_cond (cond, exitflag)
     tree cond;
     int exitflag;
{
  struct nesting *thiscond
    = (struct nesting *) xmalloc (sizeof (struct nesting));

  /* Make an entry on cond_stack for the cond we are entering.  */

  thiscond->next = cond_stack;
  thiscond->all = nesting_stack;
  thiscond->depth = ++nesting_depth;
  thiscond->data.cond.after_label = 0;
  thiscond->data.cond.else_label = gen_label_rtx ();
  thiscond->exit_label = exitflag ? thiscond->data.cond.else_label : 0;
  cond_stack = thiscond;
  nesting_stack = thiscond;

  do_jump (cond, thiscond->data.cond.else_label, NULL);
}

/* Generate RTL for the end of an if-then with no else-clause.
   Pop the record for it off of cond_stack.  */

void
expand_end_cond ()
{
  struct nesting *thiscond = cond_stack;

  do_pending_stack_adjust ();
  emit_label (thiscond->data.cond.else_label);

  POPSTACK (cond_stack);
  last_expr_type = 0;
}

/* Generate RTL between the then-clause and the else-clause
   of an if-then-else.  */

void
expand_start_else ()
{
  cond_stack->data.cond.after_label = gen_label_rtx ();
  if (cond_stack->exit_label != 0)
    cond_stack->exit_label = cond_stack->data.cond.after_label;
  emit_jump (cond_stack->data.cond.after_label);
  if (cond_stack->data.cond.else_label)
    emit_label (cond_stack->data.cond.else_label);
}

/* Generate RTL for the end of an if-then-else.
   Pop the record for it off of cond_stack.  */

void
expand_end_else ()
{
  struct nesting *thiscond = cond_stack;

  do_pending_stack_adjust ();
  /* Note: a syntax error can cause this to be called
     without first calling `expand_start_else'.  */
  if (thiscond->data.cond.after_label)
    emit_label (thiscond->data.cond.after_label);

  POPSTACK (cond_stack);
  last_expr_type = 0;
}

/* Generate RTL for the start of a loop.  EXIT_FLAG is nonzero if this
   loop should be exited by `exit_something'.  This is a loop for which
   `expand_continue' will jump to the top of the loop.

   Make an entry on loop_stack to record the labels associated with
   this loop.  */

void
expand_start_loop (exit_flag)
     int exit_flag;
{
  register struct nesting *thisloop
    = (struct nesting *) xmalloc (sizeof (struct nesting));

  /* Make an entry on loop_stack for the loop we are entering.  */

  thisloop->next = loop_stack;
  thisloop->all = nesting_stack;
  thisloop->depth = ++nesting_depth;
  thisloop->data.loop.start_label = gen_label_rtx ();
  thisloop->data.loop.end_label = gen_label_rtx ();
  thisloop->data.loop.continue_label = thisloop->data.loop.start_label;
  thisloop->exit_label = exit_flag ? thisloop->data.loop.end_label : 0;
  loop_stack = thisloop;
  nesting_stack = thisloop;

  do_pending_stack_adjust ();
  emit_queue ();
  emit_note (0, NOTE_INSN_LOOP_BEG);
  emit_label (thisloop->data.loop.start_label);
}

/* Like expand_start_loop but for a loop where the continuation point
   (for expand_continue_loop) will be specified explicitly.  */

void
expand_start_loop_continue_elsewhere (exit_flag)
     int exit_flag;
{
  expand_start_loop (exit_flag);
  loop_stack->data.loop.continue_label = gen_label_rtx ();
}

/* Specify the continuation point for a loop started with
   expand_start_loop_continue_elsewhere.
   Use this at the point in the code to which a continue statement
   should jump.  */

void
expand_loop_continue_here ()
{
  do_pending_stack_adjust ();
  emit_label (loop_stack->data.loop.continue_label);
}

/* Finish a loop.  Generate a jump back to the top and the loop-exit label.
   Pop the block off of loop_stack.  */

void
expand_end_loop ()
{
  register rtx insn = get_last_insn ();
  register rtx start_label = loop_stack->data.loop.start_label;

  do_pending_stack_adjust ();

  /* If optimizing, perhaps reorder the loop.  If the loop
     starts with a conditional exit, roll that to the end
     where it will optimize together with the jump back.  */
  if (optimize
      &&
      ! (GET_CODE (insn) == JUMP_INSN
	 && GET_CODE (PATTERN (insn)) == SET
	 && SET_DEST (PATTERN (insn)) == pc_rtx
	 && GET_CODE (SET_SRC (PATTERN (insn))) == IF_THEN_ELSE))
    {
      /* Scan insns from the top of the loop looking for a qualified
	 conditional exit.  */
      for (insn = loop_stack->data.loop.start_label; insn; insn= NEXT_INSN (insn))
	if (GET_CODE (insn) == JUMP_INSN && GET_CODE (PATTERN (insn)) == SET
	    && SET_DEST (PATTERN (insn)) == pc_rtx
	    && GET_CODE (SET_SRC (PATTERN (insn))) == IF_THEN_ELSE
	    &&
	    ((GET_CODE (XEXP (SET_SRC (PATTERN (insn)), 1)) == LABEL_REF
	      && (XEXP (XEXP (SET_SRC (PATTERN (insn)), 1), 0)
		  == loop_stack->data.loop.end_label))
	     ||
	     (GET_CODE (XEXP (SET_SRC (PATTERN (insn)), 2)) == LABEL_REF
	      && (XEXP (XEXP (SET_SRC (PATTERN (insn)), 2), 0)
		  == loop_stack->data.loop.end_label))))
	  break;
      if (insn != 0)
	{
	  /* We found one.  Move everything from there up
	     to the end of the loop, and add a jump into the loop
	     to jump to there.  */
	  register rtx newstart_label = gen_label_rtx ();

	  emit_label_after (newstart_label, PREV_INSN (start_label));
	  reorder_insns (start_label, insn, get_last_insn ());
	  emit_jump_insn_after (gen_jump (start_label), PREV_INSN (newstart_label));
	  emit_barrier_after (PREV_INSN (newstart_label));
	  start_label = newstart_label;
	}
    }

  emit_jump (start_label);
  emit_note (0, NOTE_INSN_LOOP_END);
  emit_label (loop_stack->data.loop.end_label);

  POPSTACK (loop_stack);

  last_expr_type = 0;
}

/* Generate a jump to the current loop's continue-point.
   This is usually the top of the loop, but may be specified
   explicitly elsewhere.  If not currently inside a loop,
   return 0 and do nothing; caller will print an error message.  */

int
expand_continue_loop ()
{
  last_expr_type = 0;
  if (loop_stack == 0)
    return 0;
  expand_goto_internal (0, loop_stack->data.loop.continue_label, 0);
  return 1;
}

/* Generate a jump to exit the current loop.  If not currently inside a loop,
   return 0 and do nothing; caller will print an error message.  */

int
expand_exit_loop ()
{
  last_expr_type = 0;
  if (loop_stack == 0)
    return 0;
  expand_goto_internal (0, loop_stack->data.loop.end_label, 0);
  return 1;
}

/* Generate a conditional jump to exit the current loop if COND
   evaluates to zero.  If not currently inside a loop,
   return 0 and do nothing; caller will print an error message.  */

int
expand_exit_loop_if_false (cond)
     tree cond;
{
  last_expr_type = 0;
  if (loop_stack == 0)
    return 0;
  do_jump (cond, loop_stack->data.loop.end_label, NULL);
  return 1;
}

/* Generate a jump to exit the current loop, conditional, binding contour
   or case statement.  Not all such constructs are visible to this function,
   only those started with EXIT_FLAG nonzero.  Individual languages use
   the EXIT_FLAG parameter to control which kinds of constructs you can
   exit this way.

   If not currently inside anything that can be exited,
   return 0 and do nothing; caller will print an error message.  */

int
expand_exit_something ()
{
  struct nesting *n;
  last_expr_type = 0;
  for (n = nesting_stack; n; n = n->all)
    if (n->exit_label != 0)
      {
	expand_goto_internal (0, n->exit_label, 0);
	return 1;
      }

  return 0;
}

/* Generate RTL to return from the current function, with no value.
   (That is, we do not do anything about returning any value.)  */

void
expand_null_return ()
{
  expand_null_return_1 (0);
}

/* Output a return with no value.  If LAST_INSN is nonzero,
   pretend that the return takes place after LAST_INSN.  */

static void
expand_null_return_1 (last_insn)
     rtx last_insn;
{
  clear_pending_stack_adjust ();
  do_pending_stack_adjust ();
#ifdef FUNCTION_EPILOGUE
#ifdef HAVE_return
  if (! HAVE_return)
    expand_goto_internal (0, return_label, last_insn);
  else
    {
      emit_jump_insn (gen_return ());
      emit_barrier ();
    }
#else
  expand_goto_internal (0, return_label, last_insn);
#endif
#else /* no FUNCTION_EPILOGUE */
  emit_jump_insn (gen_return ());
  emit_barrier ();
#endif
  last_expr_type = 0;
}

/* Generate RTL to evaluate the expression RETVAL and return it
   from the current function.  */

void
expand_return (retval)
     tree retval;
{
  /* If there are any cleanups to be performed, then they will
     be inserted in front of our `last_insn'.  It is desirable
     that the last_insn, for such purposes, should be the
     last insn before computing the return value.  Otherwise, cleanups
     which call functions can clobber the return value.  */
  rtx last_insn = get_last_insn ();
  register rtx val = 0;
  register rtx op0;
  tree retval_rhs;

  if (TREE_CODE (retval) == RESULT_DECL)
    retval_rhs = retval;
  else if ((TREE_CODE (retval) == MODIFY_EXPR || TREE_CODE (retval) == INIT_EXPR)
	   && TREE_CODE (TREE_OPERAND (retval, 0)) == RESULT_DECL)
    retval_rhs = TREE_OPERAND (retval, 1);
  else
    retval_rhs = NULL_TREE;

  /* For tail-recursive call to current function,
     just jump back to the beginning.
     It's unsafe if any auto variable in this function
     has its address taken; for simplicity,
     require stack frame to be empty.  */
  if (optimize && retval_rhs != 0
      && frame_offset == STARTING_FRAME_OFFSET
      && TREE_CODE (retval_rhs) == CALL_EXPR
      && TREE_CODE (TREE_OPERAND (retval_rhs, 0)) == ADDR_EXPR
      && TREE_OPERAND (TREE_OPERAND (retval_rhs, 0), 0) == this_function
      /* Finish checking validity, and if valid emit code
	 to set the argument variables for the new call.  */
      && tail_recursion_args (TREE_OPERAND (retval_rhs, 1),
			      DECL_ARGUMENTS (this_function)))
    {
      ;
      if (tail_recursion_label == 0)
	{
	  tail_recursion_label = gen_label_rtx ();
	  emit_label_after (tail_recursion_label,
			    tail_recursion_reentry);
	}
      expand_goto_internal (0, tail_recursion_label, last_insn);
      emit_barrier ();
      return;
    }
#ifdef HAVE_return
  if (HAVE_return)
    {
      /* If this is  return x == y;  then generate
	 if (x == y) return 1; else return 0;
	 if we can do it with explicit return insns.  */
      if (retval_rhs)
	switch (TREE_CODE (retval_rhs))
	  {
	  case EQ_EXPR:
	  case NE_EXPR:
	  case GT_EXPR:
	  case GE_EXPR:
	  case LT_EXPR:
	  case LE_EXPR:
	  case TRUTH_ANDIF_EXPR:
	  case TRUTH_ORIF_EXPR:
	  case TRUTH_AND_EXPR:
	  case TRUTH_OR_EXPR:
	  case TRUTH_NOT_EXPR:
	    op0 = gen_label_rtx ();
	    val = DECL_RTL (DECL_RESULT (this_function));
	    jumpifnot (retval_rhs, op0);
	    emit_move_insn (val, const1_rtx);
	    emit_insn (gen_rtx (USE, VOIDmode, val));
	    expand_null_return ();
	    emit_label (op0);
	    emit_move_insn (val, const0_rtx);
	    emit_insn (gen_rtx (USE, VOIDmode, val));
	    expand_null_return ();
	    return;
	  }
    }
#endif /* HAVE_return */
  val = expand_expr (retval, 0, VOIDmode, 0);
  emit_queue ();

  if (retval_rhs && GET_CODE (val) == REG)
    emit_insn (gen_rtx (USE, VOIDmode, val));

  expand_null_return_1 (last_insn);
}

/* Return 1 if the end of the generated RTX is not a barrier.
   This means code already compiled can drop through.  */

int
drop_through_at_end_p ()
{
  rtx insn = get_last_insn ();
  while (insn && GET_CODE (insn) == NOTE)
    insn = PREV_INSN (insn);
  return insn && GET_CODE (insn) != BARRIER;
}

/* Emit code to alter this function's formal parms for a tail-recursive call.
   ACTUALS is a list of actual parameter expressions (chain of TREE_LISTs).
   FORMALS is the chain of decls of formals.
   Return 1 if this can be done;
   otherwise return 0 and do not emit any code.  */

static int
tail_recursion_args (actuals, formals)
     tree actuals, formals;
{
  register tree a = actuals, f = formals;
  register int i;
  register rtx *argvec;

  /* Check that number and types of actuals are compatible
     with the formals.  This is not always true in valid C code.
     Also check that no formal needs to be addressable
     and that all formals are scalars.  */

  /* Also count the args.  */

  for (a = actuals, f = formals, i = 0; a && f; a = TREE_CHAIN (a), f = TREE_CHAIN (f), i++)
    {
      if (TREE_TYPE (TREE_VALUE (a)) != TREE_TYPE (f))
	return 0;
      if (GET_CODE (DECL_RTL (f)) != REG || DECL_MODE (f) == BLKmode)
	return 0;
    }
  if (a != 0 || f != 0)
    return 0;

  /* Compute all the actuals.  */

  argvec = (rtx *) alloca (i * sizeof (rtx));

  for (a = actuals, i = 0; a; a = TREE_CHAIN (a), i++)
    argvec[i] = expand_expr (TREE_VALUE (a), 0, VOIDmode, 0);

  /* Find which actual values refer to current values of previous formals.
     Copy each of them now, before any formal is changed.  */

  for (a = actuals, i = 0; a; a = TREE_CHAIN (a), i++)
    {
      int copy = 0;
      register int j;
      for (f = formals, j = 0; j < i; f = TREE_CHAIN (f), j++)
	if (reg_mentioned_p (DECL_RTL (f), argvec[i]))
	  { copy = 1; break; }
      if (copy)
	argvec[i] = copy_to_reg (argvec[i]);
    }

  /* Store the values of the actuals into the formals.  */

  for (f = formals, a = actuals, i = 0; f;
       f = TREE_CHAIN (f), a = TREE_CHAIN (a), i++)
    {
      if (DECL_MODE (f) == GET_MODE (argvec[i]))
	emit_move_insn (DECL_RTL (f), argvec[i]);
      else
	convert_move (DECL_RTL (f), argvec[i],
		      TREE_UNSIGNED (TREE_TYPE (TREE_VALUE (a))));
    }

  return 1;
}

/* Generate the RTL code for entering a binding contour.
   The variables are declared one by one, by calls to `expand_decl'.

   EXIT_FLAG is nonzero if this construct should be visible to
   `exit_something'.  */

void
expand_start_bindings (exit_flag)
     int exit_flag;
{
  struct nesting *thisblock
    = (struct nesting *) xmalloc (sizeof (struct nesting));

  rtx note = emit_note (0, NOTE_INSN_BLOCK_BEG);

  /* Make an entry on block_stack for the block we are entering.  */

  thisblock->next = block_stack;
  thisblock->all = nesting_stack;
  thisblock->depth = ++nesting_depth;
  thisblock->data.block.stack_level = 0;
  thisblock->data.block.cleanups = 0;
  thisblock->data.block.label_chain = 0;
  thisblock->data.block.innermost_stack_block = stack_block_stack;
  thisblock->data.block.first_insn = note;
  thisblock->exit_label = exit_flag ? gen_label_rtx () : 0;
  block_stack = thisblock;
  nesting_stack = thisblock;
}

/* Output a USE for any register use in RTL.
   This is used with -noreg to mark the extent of lifespan
   of any registers used in a user-visible variable's DECL_RTL.  */

static void
use_variable (rtl)
     rtx rtl;
{
  if (GET_CODE (rtl) == REG)
    /* This is a register variable.  */
    emit_insn (gen_rtx (USE, VOIDmode, rtl));
  else if (GET_CODE (rtl) == MEM
	   && GET_CODE (XEXP (rtl, 0)) == REG
	   && XEXP (rtl, 0) != frame_pointer_rtx
	   && XEXP (rtl, 0) != arg_pointer_rtx)
    /* This is a variable-sized structure.  */
    emit_insn (gen_rtx (USE, VOIDmode, XEXP (rtl, 0)));
}

/* Generate RTL code to terminate a binding contour.
   VARS is the chain of VAR_DECL nodes
   for the variables bound in this contour.
   MARK_ENDS is nonzero if we should put a note at the beginning
   and end of this binding contour.

   DONT_JUMP_IN is nonzero if it is not valid to jump into this contour.
   (That is true automatically if the contour has a saved stack level.)  */

void
expand_end_bindings (vars, mark_ends, dont_jump_in)
     tree vars;
     int mark_ends;
     int dont_jump_in;
{
  register struct nesting *thisblock = block_stack;
  register tree decl;

  if (warn_unused)
    for (decl = vars; decl; decl = TREE_CHAIN (decl))
      if (! TREE_USED (decl) && TREE_CODE (decl) == VAR_DECL)
	warning_with_decl (decl, "unused variable `%s'");

  /* Mark the beginning and end of the scope if requested.  */

  if (mark_ends)
    emit_note (0, NOTE_INSN_BLOCK_END);
  else
    /* Get rid of the beginning-mark if we don't make an end-mark.  */
    NOTE_LINE_NUMBER (thisblock->data.block.first_insn) = NOTE_INSN_DELETED;

  if (thisblock->exit_label)
    {
      do_pending_stack_adjust ();
      emit_label (thisblock->exit_label);
    }

  if (dont_jump_in || thisblock->data.block.stack_level != 0)
    {
      struct label_chain *chain;

      /* Any labels in this block are no longer valid to go to.
	 Mark them to cause an error message.  */
      for (chain = thisblock->data.block.label_chain; chain; chain = chain->next)
	{
	  TREE_PACKED (chain->label) = 1;
	  /* If any goto without a fixup came to this label,
	     that must be an error, because gotos without fixups
	     come from outside all saved stack-levels.  */
	  if (TREE_ADDRESSABLE (chain->label))
	    error_with_file_and_line (DECL_SOURCE_FILE (chain->label),
				      DECL_SOURCE_LINE (chain->label),
				      "label \"%s\" was used \
before containing binding contour",
				      IDENTIFIER_POINTER (DECL_NAME (chain->label)));
	}
    }

  /* Restore stack level in effect before the block
     (only if variable-size objects allocated).  */

  if (thisblock->data.block.stack_level != 0
      || thisblock->data.block.cleanups != 0)
    {
      /* Perform any cleanups associated with the block.  */

      expand_cleanups (thisblock->data.block.cleanups, 0);

      /* Restore the stack level.  */

      if (thisblock->data.block.stack_level != 0)
	{
	  do_pending_stack_adjust ();
	  emit_move_insn (stack_pointer_rtx,
			  thisblock->data.block.stack_level);
	}

      /* Any gotos out of this block must also do these things.
	 Also report any gotos with fixups that came to labels in this level.  */
      fixup_gotos (thisblock->data.block.stack_level,
		   thisblock->data.block.cleanups,
		   thisblock->data.block.first_insn,
		   dont_jump_in);
    }

  /* If doing stupid register allocation, make sure lives of all
     register variables declared here extend thru end of scope.  */

  if (obey_regdecls)
    for (decl = vars; decl; decl = TREE_CHAIN (decl))
      {
	rtx rtl = DECL_RTL (decl);
	if (TREE_CODE (decl) == VAR_DECL && rtl != 0)
	  use_variable (rtl);
      }

  /* Restore block_stack level for containing block.  */

  stack_block_stack = thisblock->data.block.innermost_stack_block;
  POPSTACK (block_stack);
}

/* Generate RTL for the automatic variable declaration DECL.
   (Other kinds of declarations are simply ignored if seen here.)
   CLEANUP is an expression to be executed at exit from this binding contour;
   for example, in C++, it might call the destructor for this variable.

   If CLEANUP contains any SAVE_EXPRs, then you must preevaluate them
   either before or after calling `expand_decl' but before compiling
   any subsequent expressions.  This is because CLEANUP may be expanded
   more than once, on different branches of execution.
   For the same reason, CLEANUP may not contain a CALL_EXPR
   except as its topmost node--else `preexpand_calls' would get confused.

   There is no special support here for C++ constructors.
   They should be handled by the proper code in DECL_INITIAL.  */

void
expand_decl (decl, cleanup)
     register tree decl;
     tree cleanup;
{
  struct nesting *thisblock = block_stack;
  tree type = TREE_TYPE (decl);

  /* External function declarations are supposed to have been
     handled in assemble_variable.  Verify this.  */

  if (TREE_CODE (decl) == FUNCTION_DECL)
    {
      if (DECL_RTL (decl) == 0)
	abort ();
      return;
    }

  /* Record the cleanup if there is one.  */

  if (cleanup != 0)
    thisblock->data.block.cleanups
      = temp_tree_cons (decl, cleanup, thisblock->data.block.cleanups);

  /* Aside from that, only automatic variables need any expansion done.
     Static and external variables were handled by `assemble_variable'
     (called from finish_decl).  TYPE_DECL and CONST_DECL require nothing;
     PARM_DECLs are handled in `assign_parms'.  */

  if (TREE_CODE (decl) != VAR_DECL)
    return;
  if (TREE_STATIC (decl) || TREE_EXTERNAL (decl))
    return;

  /* Create the RTL representation for the variable.  */

  if (type == error_mark_node)
    DECL_RTL (decl) = gen_rtx (MEM, BLKmode, const0_rtx);
  else if (DECL_MODE (decl) != BLKmode
	   /* If -ffloat-store, don't put explicit float vars
	      into regs.  */
	   && !(flag_float_store
		&& TREE_CODE (type) == REAL_TYPE)
	   && ! TREE_VOLATILE (decl)
	   && ! TREE_ADDRESSABLE (decl)
	   && (TREE_REGDECL (decl) || ! obey_regdecls))
    {
      /* Automatic variable that can go in a register.  */
      DECL_RTL (decl) = gen_reg_rtx (DECL_MODE (decl));
      if (TREE_CODE (type) == POINTER_TYPE)
	mark_reg_pointer (DECL_RTL (decl));
      REG_USERVAR_P (DECL_RTL (decl)) = 1;
    }
  else if (DECL_SIZE (decl) == 0)
    /* Variable with incomplete type.  */
    /* Error message was already done; now avoid a crash.  */
    DECL_RTL (decl) = assign_stack_local (DECL_MODE (decl), 0);
  else if (TREE_LITERAL (DECL_SIZE (decl)))
    {
      /* Variable of fixed size that goes on the stack.  */
      DECL_RTL (decl)
	= assign_stack_local (DECL_MODE (decl),
			      (TREE_INT_CST_LOW (DECL_SIZE (decl))
			       * DECL_SIZE_UNIT (decl)
			       + BITS_PER_UNIT - 1)
			      / BITS_PER_UNIT);
      /* If this is a memory ref that contains aggregate components,
	 mark it as such for cse and loop optimize.  */
      MEM_IN_STRUCT_P (DECL_RTL (decl))
	= (TREE_CODE (TREE_TYPE (decl)) == ARRAY_TYPE
	   || TREE_CODE (TREE_TYPE (decl)) == RECORD_TYPE
	   || TREE_CODE (TREE_TYPE (decl)) == UNION_TYPE);
#if 0
      /* If this is in memory because of -ffloat-store,
	 set the volatile bit, to prevent optimizations from
	 undoing the effects.  */
      if (flag_float_store && TREE_CODE (type) == REAL_TYPE)
	MEM_VOLATILE_P (DECL_RTL (decl)) = 1;
#endif
    }
  else
    /* Dynamic-size object: must push space on the stack.  */
    {
      rtx address, size;

      frame_pointer_needed = 1;

      /* Record the stack pointer on entry to block, if have
	 not already done so.  */
      if (thisblock->data.block.stack_level == 0)
	{
	  do_pending_stack_adjust ();
	  thisblock->data.block.stack_level
	    = copy_to_reg (stack_pointer_rtx);
	  stack_block_stack = thisblock;
	}

      /* Compute the variable's size, in bytes.  */
      size = expand_expr (convert_units (DECL_SIZE (decl),
					 DECL_SIZE_UNIT (decl),
					 BITS_PER_UNIT),
			  0, VOIDmode, 0);

      /* Round it up to this machine's required stack boundary.  */
#ifdef STACK_BOUNDARY
      /* Avoid extra code if we can prove it's a multiple already.  */
      if (DECL_SIZE_UNIT (decl) % STACK_BOUNDARY)
	size = round_push (size);
#endif

      /* Make space on the stack, and get an rtx for the address of it.  */
#ifdef STACK_GROWS_DOWNWARD
      anti_adjust_stack (size);
#endif
      address = copy_to_reg (stack_pointer_rtx);
#ifdef STACK_POINTER_OFFSET
      /* If the contents of the stack pointer reg are offset from the
	 actual top-of-stack address, add the offset here.  */
      emit_insn (gen_add2_insn (address, gen_rtx (CONST_INT, VOIDmode,
						  STACK_POINTER_OFFSET)));
#endif
#ifndef STACK_GROWS_DOWNWARD
      anti_adjust_stack (size);
#endif

      /* Reference the variable indirect through that rtx.  */
      DECL_RTL (decl) = gen_rtx (MEM, DECL_MODE (decl), address);
    }

  if (TREE_VOLATILE (decl))
    MEM_VOLATILE_P (DECL_RTL (decl)) = 1;
  if (TREE_READONLY (decl))
    RTX_UNCHANGING_P (DECL_RTL (decl)) = 1;

  /* If doing stupid register allocation, make sure life of any
     register variable starts here, at the start of its scope.  */

  if (obey_regdecls
      && TREE_CODE (decl) == VAR_DECL
      && DECL_RTL (decl) != 0)
    use_variable (DECL_RTL (decl));

  /* Compute and store the initial value now.  */

  if (DECL_INITIAL (decl) == error_mark_node)
    {
      enum tree_code code = TREE_CODE (TREE_TYPE (decl));
      if (code == INTEGER_TYPE || code == REAL_TYPE || code == ENUMERAL_TYPE
	  || code == POINTER_TYPE)
	expand_assignment (decl, convert (TREE_TYPE (decl), integer_zero_node),
			   0, 0);
      emit_queue ();
    }
  else if (DECL_INITIAL (decl) && TREE_CODE (DECL_INITIAL (decl)) != TREE_LIST)
    {
      emit_line_note (DECL_SOURCE_FILE (decl), DECL_SOURCE_LINE (decl));
      expand_assignment (decl, DECL_INITIAL (decl), 0, 0);
      emit_queue ();
    }
}

/* Expand a list of cleanups LIST.
   Elements may be expressions or may be nested lists.

   If DONT_DO is nonnull, then any list-element
   whose TREE_PURPOSE matches DONT_DO is omitted.
   This is sometimes used to avoid a cleanup associated with
   a value that is being returned out of the scope.  */

static void
expand_cleanups (list, dont_do)
     tree list;
     tree dont_do;
{
  tree tail;
  for (tail = list; tail; tail = TREE_CHAIN (tail))
    if (dont_do == 0 || TREE_PURPOSE (tail) != dont_do)
      {
	if (TREE_CODE (TREE_VALUE (tail)) == TREE_LIST)
	  expand_cleanups (TREE_VALUE (tail), dont_do);
	else
	  expand_expr (TREE_VALUE (tail), const0_rtx, VOIDmode, 0);
      }
}

/* Expand a list of cleanups for a goto fixup.
   The expansion is put into the insn chain after the insn *BEFORE_JUMP
   and *BEFORE_JUMP is set to the insn that now comes before the jump.  */

static void
fixup_cleanups (list, before_jump)
     tree list;
     rtx *before_jump;
{
  rtx beyond_jump = get_last_insn ();
  rtx new_before_jump;

  expand_cleanups (list, 0);
  new_before_jump = get_last_insn ();

  reorder_insns (NEXT_INSN (beyond_jump), new_before_jump, *before_jump);
  *before_jump = new_before_jump;
}

/* Move all cleanups from the current block_stack
   to the containing block_stack, where they are assumed to
   have been created.  If anything can cause a temporary to
   be created, but not expanded for more than one level of
   block_stacks, then this code will have to change.  */

void
move_cleanups_up ()
{
  struct nesting *block = block_stack;
  struct nesting *outer = block->next;

  outer->data.block.cleanups
    = chainon (outer->data.block.cleanups,
	       block->data.block.cleanups);
  block->data.block.cleanups = 0;
}

/* Enter a case (Pascal) or switch (C) statement.
   Push a block onto case_stack and nesting_stack
   to accumulate the case-labels that are seen
   and to record the labels generated for the statement.

   EXIT_FLAG is nonzero if `exit_something' should exit this case stmt.
   Otherwise, this construct is transparent for `exit_something'.

   EXPR is the index-expression to be dispatched on.
   TYPE is its nominal type.  We could simply convert EXPR to this type,
   but instead we take short cuts.  */

void
expand_start_case (exit_flag, expr, type)
     int exit_flag;
     tree expr;
     tree type;
{
  register struct nesting *thiscase
    = (struct nesting *) xmalloc (sizeof (struct nesting));

  /* Make an entry on case_stack for the case we are entering.  */

  thiscase->next = case_stack;
  thiscase->all = nesting_stack;
  thiscase->depth = ++nesting_depth;
  thiscase->exit_label = exit_flag ? gen_label_rtx () : 0;
  thiscase->data.case_stmt.case_list = 0;
  thiscase->data.case_stmt.index_expr = expr;
  thiscase->data.case_stmt.nominal_type = type;
  thiscase->data.case_stmt.has_default = 0;
  case_stack = thiscase;
  nesting_stack = thiscase;

  do_pending_stack_adjust ();

  /* Make sure case_stmt.start points to something that won't
     need any transformation before expand_end_case.  */
  if (GET_CODE (get_last_insn ()) != NOTE)
    emit_note (0, NOTE_INSN_DELETED);

  thiscase->data.case_stmt.start = get_last_insn ();
}

/* Start a "dummy case statement" within which case labels are invalid
   and are not connected to any larger real case statement.
   This can be used if you don't want to let a case statement jump
   into the middle of certain kinds of constructs.  */

void
expand_start_case_dummy ()
{
  register struct nesting *thiscase
    = (struct nesting *) xmalloc (sizeof (struct nesting));

  /* Make an entry on case_stack for the dummy.  */

  thiscase->next = case_stack;
  thiscase->all = nesting_stack;
  thiscase->depth = ++nesting_depth;
  thiscase->exit_label = 0;
  thiscase->data.case_stmt.case_list = 0;
  thiscase->data.case_stmt.start = 0;
  thiscase->data.case_stmt.nominal_type = 0;
  thiscase->data.case_stmt.has_default = 0;
  case_stack = thiscase;
  nesting_stack = thiscase;
}

/* End a dummy case statement.  */

void
expand_end_case_dummy ()
{
  POPSTACK (case_stack);
}

/* Accumulate one case or default label inside a case or switch statement.
   VALUE is the value of the case (a null pointer, for a default label).

   If not currently inside a case or switch statement, return 1 and do
   nothing.  The caller will print a language-specific error message.
   If VALUE is a duplicate or overlaps, return 2 and do nothing.
   If VALUE is out of range, return 3 and do nothing.
   Return 0 on success.  */

int
pushcase (value, label)
     register tree value;
     register tree label;
{
  register tree l;
  tree index_type;
  tree nominal_type;

  /* Fail if not inside a real case statement.  */
  if (! (case_stack && case_stack->data.case_stmt.start))
    return 1;

  index_type = TREE_TYPE (case_stack->data.case_stmt.index_expr);
  nominal_type = case_stack->data.case_stmt.nominal_type;

  /* If the index is erroneous, avoid more problems: pretend to succeed.  */
  if (index_type == error_mark_node)
    return 0;

  /* Convert VALUE to the type in which the comparisons are nominally done.  */
  if (value != 0)
    value = convert (nominal_type, value);

  /* Fail if this value is out of range for the actual type of the index
     (which may be narrower than NOMINAL_TYPE).  */
  if (value != 0 && ! int_fits_type_p (value, index_type))
    return 3;

  /* Fail if this is a duplicate or overlaps another entry.  */
  if (value == 0)
    {
      if (case_stack->data.case_stmt.has_default)
	return 2;
      case_stack->data.case_stmt.has_default = 1;
    }
  else
    {
      for (l = case_stack->data.case_stmt.case_list; l; l = TREE_CHAIN (l))
	{
	  tree elem = TREE_PURPOSE (l);

	  if (elem == 0)
	    ;
	  else if (TREE_CODE (elem) == INTEGER_CST)
	    {
	      if (tree_int_cst_equal (value, elem))
		return 2;
	    }
	  else if (TREE_CODE (elem) == RANGE_EXPR)
	    {
	      if (! tree_int_cst_lt (value, TREE_OPERAND (elem, 0))
		  && ! tree_int_cst_lt (TREE_OPERAND (elem, 1), value))
		return 2;
	    }
	  else abort ();
	}
    }

  /* Add this label to the list, and succeed.
     Copy VALUE so it is temporary rather than momentary.  */
  case_stack->data.case_stmt.case_list
    = tree_cons (value ? copy_node (value) : 0, label,
	         case_stack->data.case_stmt.case_list);
  expand_label (label);
  return 0;
}

#if 0
/* Like pushcase but this case applies to all values
   between VALUE1 and VALUE2 (inclusive).
   The return value is the same as that of pushcase
   but there is one additional error code:
   4 means the specified range was empty.

   Note that this does not currently work, since expand_end_case
   has yet to be extended to handle RANGE_EXPRs.  */

int
pushcase_range (value1, value2, label)
     register tree value1, value2;
     register tree label;
{
  register tree l;
  tree index_type;
  tree nominal_type;
  tree value;

  /* Fail if not inside a real case statement.  */
  if (! (case_stack && case_stack->data.case_stmt.start))
    return 1;

  index_type = TREE_TYPE (case_stack->data.case_stmt.index_expr);
  nominal_type = case_stack->data.case_stmt.nominal_type;

  /* If the index is erroneous, avoid more problems: pretend to succeed.  */
  if (index_type == error_mark_node)
    return 0;

  /* Convert VALUEs to type in which the comparisons are nominally done.  */
  if (value1 != 0)
    value1 = convert (nominal_type, value1);
  if (value2 != 0)
    value2 = convert (nominal_type, value2);

  /* Fail if these values are out of range.  */
  if (value1 != 0 && ! int_fits_type_p (value1, index_type))
    return 3;

  if (value2 != 0 && ! int_fits_type_p (value2, index_type))
    return 3;

  /* Fail if the range is empty.  */
  if (tree_int_cst_lt (value2, value1))
    return 4;

  /* If the bounds are equal, turn this into the one-value case.  */
  if (tree_int_cst_equal (value1, value2))
    return pushcase (value1, label);

  /* Construct the RANGE_EXPR that represents this range.  */
  value = build_nt (RANGE_EXPR, value1, value2);

  /* Fail if this duplicates or overlaps another entry.  */
  for (l = case_stack->data.case_stmt.case_list; l; l = TREE_CHAIN (l))
    {
      tree elem = TREE_PURPOSE (l);

      if (elem == 0)
	;
      else if (TREE_CODE (elem) == INTEGER_CST)
	{
	  if (! tree_int_cst_lt (elem, value1)
	      && ! tree_int_cst_lt (value2, elem))
	    return 2;
	}
      else if (TREE_CODE (elem) == RANGE_EXPR)
	{
	  if (! tree_int_cst_lt (TREE_OPERAND (elem, 1), value1)
	      && ! tree_int_cst_lt (value2, TREE_OPERAND (elem, 0)))
	    return 2;
	}
      else abort ();
    }

  /* Add this label to the list, and succeed.
     Copy VALUE so it is temporary rather than momentary.  */
  case_stack->data.case_stmt.case_list
    = tree_cons (value ? copy_node (value) : 0, label,
	         case_stack->data.case_stmt.case_list);
  expand_label (label);

  return 0;
}
#endif /* 0 */

/* Terminate a case (Pascal) or switch (C) statement
   in which CASE_INDEX is the expression to be tested.
   Generate the code to test it and jump to the right place.  */

void
expand_end_case ()
{
  tree minval, maxval, range;
  rtx default_label = 0;
  register tree elt;
  register tree c;
  int count;
  rtx index;
  rtx table_label = gen_label_rtx ();
  int ncases;
  rtx *labelvec;
  register int i;
  rtx before_case;
  register struct nesting *thiscase = case_stack;
  tree index_expr = thiscase->data.case_stmt.index_expr;

  do_pending_stack_adjust ();

  /* An ERROR_MARK occurs for various reasons including invalid data type.  */
  if (TREE_TYPE (index_expr) != error_mark_node)
    {
      /* If we don't have a default-label, create one here,
	 after the body of the switch.  */
      if (thiscase->data.case_stmt.has_default == 0)
	pushcase (0, build_decl (LABEL_DECL, NULL_TREE, NULL_TREE));

      before_case = get_last_insn ();

      /* Get upper and lower bounds of case values.
	 Also convert all the case values to the index expr's data type.  */
      count = 0;
      for (c = thiscase->data.case_stmt.case_list; c; c = TREE_CHAIN (c))
	if (elt = TREE_PURPOSE (c))
	  {
	    /* Note that in Pascal it will be possible
	       to have a RANGE_EXPR here as long as both
	       ends of the range are constant.
	       It will be necessary to extend this function
	       to handle them.  */
	    if (TREE_CODE (elt) != INTEGER_CST)
	      abort ();

	    TREE_PURPOSE (c) = elt = convert (TREE_TYPE (index_expr), elt);

	    /* Count the elements and track the largest and
	       smallest of them
	       (treating them as signed even if they are not).  */
	    if (count++ == 0)
	      {
		minval = maxval = elt;
	      }
	    else
	      {
		if (INT_CST_LT (elt, minval))
		  minval = elt;
		if (INT_CST_LT (maxval, elt))
		  maxval = elt;
	      }
	  }
	else
	  default_label = label_rtx (TREE_VALUE (c));

      if (default_label == 0)
	abort ();

      /* Compute span of values.  */
      if (count != 0)
	range = combine (MINUS_EXPR, maxval, minval);

      if (count == 0 || TREE_CODE (TREE_TYPE (index_expr)) == ERROR_MARK)
	{
	  expand_expr (index_expr, const0_rtx, VOIDmode, 0);
	  emit_queue ();
	  emit_jump (default_label);
	}
      /* If range of values is much bigger than number of values,
	 make a sequence of conditional branches instead of a dispatch.
	 If the switch-index is a constant, do it this way
	 because we can optimize it.  */
      else if (TREE_INT_CST_HIGH (range) != 0
#ifdef HAVE_casesi
	       || count < 4
#else
	       /* If machine does not have a case insn that compares the
		  bounds, this means extra overhead for dispatch tables
		  which raises the threshold for using them.  */
	       || count < 5
#endif
	       || (unsigned) (TREE_INT_CST_LOW (range)) > 10 * count
	       || TREE_CODE (index_expr) == INTEGER_CST)
	{
	  index = expand_expr (index_expr, 0, VOIDmode, 0);
	  emit_queue ();

	  index = protect_from_queue (index, 0);
	  if (GET_CODE (index) == MEM)
	    index = copy_to_reg (index);
	  do_pending_stack_adjust ();

	  for (c = thiscase->data.case_stmt.case_list; c; c = TREE_CHAIN (c))
	    {
	      elt = TREE_PURPOSE (c);
	      if (elt && TREE_VALUE (c))
		do_jump_if_equal (index, expand_expr (elt, 0, VOIDmode, 0),
				  label_rtx (TREE_VALUE (c)));
	    }

	  emit_jump (default_label);
	}
      else
	{
#ifdef HAVE_casesi
	  /* Convert the index to SImode.  */
	  if (TYPE_MODE (TREE_TYPE (index_expr)) == DImode)
	    {
	      index_expr = build (MINUS_EXPR, TREE_TYPE (index_expr),
				  index_expr, minval);
	      minval = integer_zero_node;
	    }
	  if (TYPE_MODE (TREE_TYPE (index_expr)) != SImode)
	    index_expr = convert (type_for_size (GET_MODE_BITSIZE (SImode), 0),
				  index_expr);
	  index = expand_expr (index_expr, 0, VOIDmode, 0);
	  emit_queue ();
	  index = protect_from_queue (index, 0);
	  do_pending_stack_adjust ();

	  emit_jump_insn (gen_casesi (index, expand_expr (minval, 0, VOIDmode, 0),
				      expand_expr (range, 0, VOIDmode, 0),
				      table_label, default_label));
#else
#ifdef HAVE_tablejump
	  index_expr = convert (type_for_size (GET_MODE_BITSIZE (SImode), 0),
				build (MINUS_EXPR, TREE_TYPE (index_expr),
				       index_expr, minval));
	  index = expand_expr (index_expr, 0, VOIDmode, 0);
	  emit_queue ();
	  index = protect_from_queue (index, 0);
	  do_pending_stack_adjust ();

	  do_tablejump (index,
			gen_rtx (CONST_INT, VOIDmode, TREE_INT_CST_LOW (range)),
			table_label, default_label);
#else
	  lossage;
#endif				/* not HAVE_tablejump */
#endif				/* not HAVE_casesi */

	  /* Get table of labels to jump to, in order of case index.  */

	  ncases = TREE_INT_CST_LOW (range) + 1;
	  labelvec = (rtx *) alloca (ncases * sizeof (rtx));
	  bzero (labelvec, ncases * sizeof (rtx));

	  for (c = thiscase->data.case_stmt.case_list; c; c = TREE_CHAIN (c))
	    if (TREE_VALUE (c) && (elt = TREE_PURPOSE (c)))
	      {
		register int i
		  = TREE_INT_CST_LOW (elt) - TREE_INT_CST_LOW (minval);
		labelvec[i]
		  = gen_rtx (LABEL_REF, Pmode, label_rtx (TREE_VALUE (c)));
	      }

	  /* Fill in the gaps with the default.  */
	  for (i = 0; i < ncases; i++)
	    if (labelvec[i] == 0)
	      labelvec[i] = gen_rtx (LABEL_REF, Pmode, default_label);

	  /* Output the table */
	  emit_label (table_label);

#ifdef CASE_VECTOR_PC_RELATIVE
	  emit_jump_insn (gen_rtx (ADDR_DIFF_VEC, CASE_VECTOR_MODE,
				   gen_rtx (LABEL_REF, Pmode, table_label),
				   gen_rtvec_v (ncases, labelvec)));
#else
	  emit_jump_insn (gen_rtx (ADDR_VEC, CASE_VECTOR_MODE,
				   gen_rtvec_v (ncases, labelvec)));
#endif
	  /* If the case insn drops through the table,
	     after the table we must jump to the default-label.
	     Otherwise record no drop-through after the table.  */
#ifdef CASE_DROPS_THROUGH
	  emit_jump (default_label);
#else
	  emit_barrier ();
#endif
	}

      reorder_insns (NEXT_INSN (before_case), get_last_insn (),
		     thiscase->data.case_stmt.start);
    }
  if (thiscase->exit_label)
    emit_label (thiscase->exit_label);

  POPSTACK (case_stack);
}

/* Generate code to jump to LABEL if OP1 and OP2 are equal.  */
/* ??? This may need an UNSIGNEDP argument to work properly ??? */

void
do_jump_if_equal (op1, op2, label)
     rtx op1, op2, label;
{
  if (GET_CODE (op1) == CONST_INT
      && GET_CODE (op2) == CONST_INT)
    {
      if (INTVAL (op1) == INTVAL (op2))
	emit_jump (label);
    }
  else
    {
      emit_cmp_insn (op1, op2, 0, 0);
      emit_jump_insn (gen_beq (label));
    }
}

/* Allocate fixed slots in the stack frame of the current function.  */

/* Return size needed for stack frame based on slots so far allocated.  */

int
get_frame_size ()
{
#ifdef FRAME_GROWS_DOWNWARD
  return -frame_offset;
#else
  return frame_offset;
#endif
}

/* Allocate a stack slot of SIZE bytes and return a MEM rtx for it
   with machine mode MODE.  */

rtx
assign_stack_local (mode, size)
     enum machine_mode mode;
     int size;
{
  register rtx x, addr;
  int bigend_correction = 0;

  frame_pointer_needed = 1;

  /* Make each stack slot a multiple of the main allocation unit.  */
  size = (((size + (BIGGEST_ALIGNMENT / BITS_PER_UNIT) - 1)
	   / (BIGGEST_ALIGNMENT / BITS_PER_UNIT))
	  * (BIGGEST_ALIGNMENT / BITS_PER_UNIT));

  /* On a big-endian machine, if we are allocating more space than we will use,
     use the least significant bytes of those that are allocated.  */
#ifdef BYTES_BIG_ENDIAN
  if (mode != BLKmode)
    bigend_correction = size - GET_MODE_SIZE (mode);
#endif

#ifdef FRAME_GROWS_DOWNWARD
  frame_offset -= size;
#endif
  addr = gen_rtx (PLUS, Pmode, frame_pointer_rtx,
		  gen_rtx (CONST_INT, VOIDmode,
			   (frame_offset + bigend_correction)));
#ifndef FRAME_GROWS_DOWNWARD
  frame_offset += size;
#endif

  if (! memory_address_p (mode, addr))
    invalid_stack_slot = 1;

  x = gen_rtx (MEM, mode, addr);

  return x;
}

/* Retroactively move an auto variable from a register to a stack slot.
   This is done when an address-reference to the variable is seen.  */

void
put_var_into_stack (decl)
     tree decl;
{
  register rtx reg = DECL_RTL (decl);
  register rtx new;

  /* No need to do anything if decl has no rtx yet
     since in that case caller is setting TREE_ADDRESSABLE
     and a stack slot will be assigned when the rtl is made.  */
  if (reg == 0)
    return;
  if (GET_CODE (reg) != REG)
    return;

  new = parm_stack_loc (reg);
  if (new == 0)
    new = assign_stack_local (GET_MODE (reg), GET_MODE_SIZE (GET_MODE (reg)));

  XEXP (reg, 0) = XEXP (new, 0);
  /* `volatil' bit means one thing for MEMs, another entirely for REGs.  */
  REG_USERVAR_P (reg) = 0;
  PUT_CODE (reg, MEM);

  /* If this is a memory ref that contains aggregate components,
     mark it as such for cse and loop optimize.  */
  MEM_IN_STRUCT_P (reg)
    = (TREE_CODE (TREE_TYPE (decl)) == ARRAY_TYPE
       || TREE_CODE (TREE_TYPE (decl)) == RECORD_TYPE
       || TREE_CODE (TREE_TYPE (decl)) == UNION_TYPE);

  fixup_var_refs (reg);
}

static void
fixup_var_refs (var)
     rtx var;
{
  register rtx insn;
  extern rtx sequence_stack;
  rtx stack = sequence_stack;
  tree pending;

  stack = sequence_stack;

  /* Must scan all insns for stack-refs that exceed the limit.  */
  fixup_var_refs_insns (var, get_insns (), stack == 0);

  /* Scan all pending sequences too.  */
  for (; stack; stack = XEXP (XEXP (stack, 1), 1))
    {
      push_to_sequence (XEXP (stack, 0));
      fixup_var_refs_insns (var, XEXP (stack, 0),
			    XEXP (XEXP (stack, 1), 1) == 0);
      end_sequence ();
    }

  /* Scan all waiting RTL_EXPRs too.  */
  for (pending = rtl_expr_chain; pending; pending = TREE_CHAIN (pending))
    {
      rtx seq = RTL_EXPR_SEQUENCE (TREE_VALUE (pending));
      if (seq != const0_rtx && seq != 0)
	{
	  push_to_sequence (seq);
	  fixup_var_refs_insns (var, seq, 0);
	  end_sequence ();
	}
    }
}

/* Scan the insn-chain starting with INSN for refs to VAR
   and fix them up.  TOPLEVEL is nonzero if this chain is the
   main chain of insns for the current function.  */

static void
fixup_var_refs_insns (var, insn, toplevel)
     rtx var;
     rtx insn;
     int toplevel;
{
  while (insn)
    {
      rtx next = NEXT_INSN (insn);
      if (GET_CODE (insn) == INSN || GET_CODE (insn) == CALL_INSN
	  || GET_CODE (insn) == JUMP_INSN)
	{
	  /* The insn to load VAR from a home in the arglist
	     is now a no-op.  When we see it, just delete it.  */
	  if (toplevel
	      && GET_CODE (PATTERN (insn)) == SET
	      && SET_DEST (PATTERN (insn)) == var
	      && rtx_equal_p (SET_SRC (PATTERN (insn)), var))
	    {
	      next = delete_insn (insn);
	      if (insn == last_parm_insn)
		last_parm_insn = PREV_INSN (next);
	    }
	  else
	    fixup_var_refs_1 (var, PATTERN (insn), insn);
	}
      insn = next;
    }
}

static rtx
fixup_var_refs_1 (var, x, insn)
     register rtx var;
     register rtx x;
     rtx insn;
{
  register int i;
  RTX_CODE code = GET_CODE (x);
  register char *fmt;
  register rtx tem;

  switch (code)
    {
    case MEM:
      if (var == x)
	{
	  x = fixup_stack_1 (x, insn);
	  tem = gen_reg_rtx (GET_MODE (x));
	  emit_insn_before (gen_move_insn (tem, x), insn);
	  return tem;
	}
      break;

    case REG:
    case CC0:
    case PC:
    case CONST_INT:
    case CONST:
    case SYMBOL_REF:
    case LABEL_REF:
    case CONST_DOUBLE:
      return x;

    case SIGN_EXTRACT:
    case ZERO_EXTRACT:
      /* Note that in some cases those types of expressions are altered
	 by optimize_bit_field, and do not survive to get here.  */
    case SUBREG:
      tem = x;
      while (GET_CODE (tem) == SUBREG || GET_CODE (tem) == SIGN_EXTRACT
	     || GET_CODE (tem) == ZERO_EXTRACT)
	tem = XEXP (tem, 0);
      if (tem == var)
	{
	  x = fixup_stack_1 (x, insn);
	  tem = gen_reg_rtx (GET_MODE (x));
	  if (GET_CODE (x) == SUBREG)
	    x = fixup_memory_subreg (x);
	  emit_insn_before (gen_move_insn (tem, x), insn);
	  return tem;
	}
      break;

    case SET:
      /* First do special simplification of bit-field references.  */
      if (GET_CODE (SET_DEST (x)) == SIGN_EXTRACT
	  || GET_CODE (SET_DEST (x)) == ZERO_EXTRACT)
	optimize_bit_field (x, insn, 0);
      if (GET_CODE (SET_SRC (x)) == SIGN_EXTRACT
	  || GET_CODE (SET_SRC (x)) == ZERO_EXTRACT)
	optimize_bit_field (x, insn, 0);

      {
	rtx dest = SET_DEST (x);
	rtx src = SET_SRC (x);
	rtx outerdest = dest;
	rtx outersrc = src;

	while (GET_CODE (dest) == SUBREG || GET_CODE (dest) == STRICT_LOW_PART
	       || GET_CODE (dest) == SIGN_EXTRACT
	       || GET_CODE (dest) == ZERO_EXTRACT)
	  dest = XEXP (dest, 0);
	while (GET_CODE (src) == SUBREG
	       || GET_CODE (src) == SIGN_EXTRACT
	       || GET_CODE (src) == ZERO_EXTRACT)
	  src = XEXP (src, 0);

	/* If VAR does not appear at the top level of the SET
	   just scan the lower levels of the tree.  */

        if (src != var && dest != var)
	  break;

	/* Clean up (SUBREG:SI (MEM:mode ...) 0)
	   that may appear inside a SIGN_EXTRACT or ZERO_EXTRACT.
	   This was legitimate when the MEM was a REG.  */

	if ((GET_CODE (outerdest) == SIGN_EXTRACT
	     || GET_CODE (outerdest) == ZERO_EXTRACT)
	    && GET_CODE (XEXP (outerdest, 0)) == SUBREG
	    && SUBREG_REG (XEXP (outerdest, 0)) == var)
	  XEXP (outerdest, 0) = fixup_memory_subreg (XEXP (outerdest, 0));

	if ((GET_CODE (outersrc) == SIGN_EXTRACT
	     || GET_CODE (outersrc) == ZERO_EXTRACT)
	    && GET_CODE (XEXP (outersrc, 0)) == SUBREG
	    && SUBREG_REG (XEXP (outersrc, 0)) == var)
	  XEXP (outersrc, 0) = fixup_memory_subreg (XEXP (outersrc, 0));

	/* Make sure a MEM inside a SIGN_EXTRACT has QImode
	   since that's what bit-field insns want.  */

	if ((GET_CODE (outerdest) == SIGN_EXTRACT
	     || GET_CODE (outerdest) == ZERO_EXTRACT)
	    && GET_CODE (XEXP (outerdest, 0)) == MEM
	    && GET_MODE (XEXP (outerdest, 0)) != QImode)
	  {
	    XEXP (outerdest, 0) = copy_rtx (XEXP (outerdest, 0));
	    PUT_MODE (XEXP (outerdest, 0), QImode);
	  }

	if ((GET_CODE (outersrc) == SIGN_EXTRACT
	     || GET_CODE (outersrc) == ZERO_EXTRACT)
	    && GET_CODE (XEXP (outersrc, 0)) == MEM
	    && GET_MODE (XEXP (outersrc, 0)) != QImode)
	  {
	    XEXP (outersrc, 0) = copy_rtx (XEXP (outersrc, 0));
	    PUT_MODE (XEXP (outersrc, 0), QImode);
	  }

	/* STRICT_LOW_PART is a no-op on memory references
	   and it can cause combinations to be unrecognizable,
	   so eliminate it.  */

	if (dest == var && GET_CODE (SET_DEST (x)) == STRICT_LOW_PART)
	  SET_DEST (x) = XEXP (SET_DEST (x), 0);

	/* An insn to copy VAR into or out of a register
	   must be left alone, to avoid an infinite loop here.
	   But do fix up the address of VAR's stack slot if nec,
	   and fix up SUBREGs containing VAR
	   (since they are now memory subregs).  */

	if (GET_CODE (SET_SRC (x)) == REG || GET_CODE (SET_DEST (x)) == REG
	    || (GET_CODE (SET_SRC (x)) == SUBREG
		&& GET_CODE (SUBREG_REG (SET_SRC (x))) == REG)
	    || (GET_CODE (SET_DEST (x)) == SUBREG
		&& GET_CODE (SUBREG_REG (SET_DEST (x))) == REG))
	  {
	    if (src == var && GET_CODE (SET_SRC (x)) == SUBREG)
	      SET_SRC (x) = fixup_memory_subreg (SET_SRC (x));
	    if (dest == var && GET_CODE (SET_DEST (x)) == SUBREG)
	      SET_DEST (x) = fixup_memory_subreg (SET_DEST (x));
	    return fixup_stack_1 (x, insn);
	  }

	/* Otherwise, storing into VAR must be handled specially
	   by storing into a temporary and copying that into VAR
	   with a new insn after this one.  */

	if (dest == var)
	  {
	    rtx temp;
	    rtx fixeddest;
	    tem = SET_DEST (x);
	    /* STRICT_LOW_PART can be discarded, around a MEM.  */
	    if (GET_CODE (tem) == STRICT_LOW_PART)
	      tem = XEXP (tem, 0);
	    /* Convert (SUBREG (MEM)) to a MEM in a changed mode.  */
	    if (GET_CODE (tem) == SUBREG)
	      tem = fixup_memory_subreg (tem);
	    fixeddest = fixup_stack_1 (tem, insn);
	    temp = gen_reg_rtx (GET_MODE (tem));
	    emit_insn_after (gen_move_insn (fixeddest, temp), insn);
	    SET_DEST (x) = temp;
	  }
      }
    }

  /* Nothing special about this RTX; fix its operands.  */

  fmt = GET_RTX_FORMAT (code);
  for (i = GET_RTX_LENGTH (code) - 1; i >= 0; i--)
    {
      if (fmt[i] == 'e')
	XEXP (x, i) = fixup_var_refs_1 (var, XEXP (x, i), insn);
      if (fmt[i] == 'E')
	{
	  register int j;
	  for (j = 0; j < XVECLEN (x, i); j++)
	    XVECEXP (x, i, j)
	      = fixup_var_refs_1 (var, XVECEXP (x, i, j), insn);
	}
    }
  return x;
}

/* Given X, an rtx of the form (SUBREG:m1 (MEM:m2 addr)),
   return an rtx (MEM:m1 newaddr) which is equivalent.  */

static rtx
fixup_memory_subreg (x)
     rtx x;
{
  int offset = SUBREG_WORD (x) * UNITS_PER_WORD;
  rtx addr = XEXP (SUBREG_REG (x), 0);
  enum machine_mode mode = GET_MODE (x);

#ifdef BYTES_BIG_ENDIAN
  offset += (MIN (UNITS_PER_WORD, GET_MODE_SIZE (GET_MODE (SUBREG_REG (x))))
	     - MIN (UNITS_PER_WORD, GET_MODE_SIZE (GET_MODE (x))));
#endif
  return change_address (SUBREG_REG (x), mode,
			 plus_constant (addr, offset));
}

#if 0
/* Fix up any references to stack slots that are invalid memory addresses
   because they exceed the maximum range of a displacement.  */

void
fixup_stack_slots ()
{
  register rtx insn;

  /* Did we generate a stack slot that is out of range
     or otherwise has an invalid address?  */
  if (invalid_stack_slot)
    {
      /* Yes.  Must scan all insns for stack-refs that exceed the limit.  */
      for (insn = get_insns (); insn; insn = NEXT_INSN (insn))
	if (GET_CODE (insn) == INSN || GET_CODE (insn) == CALL_INSN
	    || GET_CODE (insn) == JUMP_INSN)
	  fixup_stack_1 (PATTERN (insn), insn);
    }
}
#endif

/* For each memory ref within X, if it refers to a stack slot
   with an out of range displacement, put the address in a temp register
   (emitting new insns before INSN to load these registers)
   and alter the memory ref to use that register.
   Replace each such MEM rtx with a copy, to avoid clobberage.  */

static rtx
fixup_stack_1 (x, insn)
     rtx x;
     rtx insn;
{
  register int i;
  register RTX_CODE code = GET_CODE (x);
  register char *fmt;

  if (code == MEM)
    {
      register rtx ad = XEXP (x, 0);
      /* If we have address of a stack slot but it's not valid
	 (displacement is too large), compute the sum in a register.  */
      if (GET_CODE (ad) == PLUS
	  && XEXP (ad, 0) == frame_pointer_rtx
	  && GET_CODE (XEXP (ad, 1)) == CONST_INT)
	{
	  rtx temp;
	  if (memory_address_p (GET_MODE (x), ad))
	    return x;
	  temp = gen_reg_rtx (GET_MODE (ad));
	  emit_insn_before (gen_move_insn (temp, ad), insn);
	  return change_address (x, VOIDmode, temp);
	}
      return x;
    }

  fmt = GET_RTX_FORMAT (code);
  for (i = GET_RTX_LENGTH (code) - 1; i >= 0; i--)
    {
      if (fmt[i] == 'e')
	XEXP (x, i) = fixup_stack_1 (XEXP (x, i), insn);
      if (fmt[i] == 'E')
	{
	  register int j;
	  for (j = 0; j < XVECLEN (x, i); j++)
	    XVECEXP (x, i, j) = fixup_stack_1 (XVECEXP (x, i, j), insn);
	}
    }
  return x;
}

/* Optimization: a bit-field instruction whose field
   happens to be a byte or halfword in memory
   can be changed to a move instruction.

   We call here when INSN is an insn to examine or store into a bit-field.
   BODY is the SET-rtx to be altered.

   EQUIV_MEM is the table `reg_equiv_mem' if that is available; else 0.
   (Currently this is called only from stmt.c, and EQUIV_MEM is always 0.)  */

static void
optimize_bit_field (body, insn, equiv_mem)
     rtx body;
     rtx insn;
     rtx *equiv_mem;
{
  register rtx bitfield;
  int destflag;

  if (GET_CODE (SET_DEST (body)) == SIGN_EXTRACT
      || GET_CODE (SET_DEST (body)) == ZERO_EXTRACT)
    bitfield = SET_DEST (body), destflag = 1;
  else
    bitfield = SET_SRC (body), destflag = 0;

  /* First check that the field being stored has constant size and position
     and is in fact a byte or halfword suitably aligned.  */

  if (GET_CODE (XEXP (bitfield, 1)) == CONST_INT
      && GET_CODE (XEXP (bitfield, 2)) == CONST_INT
      && (INTVAL (XEXP (bitfield, 1)) == GET_MODE_BITSIZE (QImode)
	  || INTVAL (XEXP (bitfield, 1)) == GET_MODE_BITSIZE (HImode))
      && INTVAL (XEXP (bitfield, 2)) % INTVAL (XEXP (bitfield, 1)) == 0)
    {
      register rtx memref = 0;

      /* Now check that the containing word is memory, not a register,
	 and that it is safe to change the machine mode and to
	 add something to the address.  */

      if (GET_CODE (XEXP (bitfield, 0)) == MEM)
	memref = XEXP (bitfield, 0);
      else if (GET_CODE (XEXP (bitfield, 0)) == REG
	       && equiv_mem != 0)
	memref = equiv_mem[REGNO (XEXP (bitfield, 0))];
      else if (GET_CODE (XEXP (bitfield, 0)) == SUBREG
	       && GET_CODE (SUBREG_REG (XEXP (bitfield, 0))) == MEM)
	memref = SUBREG_REG (XEXP (bitfield, 0));
      else if (GET_CODE (XEXP (bitfield, 0)) == SUBREG
	       && equiv_mem != 0
	       && GET_CODE (SUBREG_REG (XEXP (bitfield, 0))) == REG)
	memref = equiv_mem[REGNO (SUBREG_REG (XEXP (bitfield, 0)))];

      if (memref
	  && ! mode_dependent_address_p (XEXP (memref, 0))
	  && offsetable_address_p (GET_MODE (bitfield), XEXP (memref, 0)))
	{
	  /* Now adjust the address, first for any subreg'ing
	     that we are now getting rid of,
	     and then for which byte of the word is wanted.  */

	  register int offset
	    = INTVAL (XEXP (bitfield, 2)) / GET_MODE_BITSIZE (QImode);
	  if (GET_CODE (XEXP (bitfield, 0)) == SUBREG)
	    {
	      offset += SUBREG_WORD (XEXP (bitfield, 0)) * UNITS_PER_WORD;
#ifdef BYTES_BIG_ENDIAN
	      offset -= (MIN (UNITS_PER_WORD,
			      GET_MODE_SIZE (GET_MODE (XEXP (bitfield, 0))))
			 - MIN (UNITS_PER_WORD,
				GET_MODE_SIZE (GET_MODE (memref))));
#endif
	    }

	  memref = gen_rtx (MEM,
			    (INTVAL (XEXP (bitfield, 1)) == GET_MODE_BITSIZE (QImode)
			     ? QImode : HImode),
			    XEXP (memref, 0));

	  /* Store this memory reference where
	     we found the bit field reference.  */

	  if (destflag)
	    {
	      SET_DEST (body)
		= adj_offsetable_operand (memref, offset);
	      if (! CONSTANT_ADDRESS_P (SET_SRC (body)))
		{
		  rtx src = SET_SRC (body);
		  while (GET_CODE (src) == SUBREG
			 && SUBREG_WORD (src) == 0)
		    src = SUBREG_REG (src);
		  if (GET_MODE (src) != GET_MODE (memref))
		    src = gen_lowpart (GET_MODE (memref), SET_SRC (body));
		  SET_SRC (body) = src;
		}
	      else if (GET_MODE (SET_SRC (body)) != VOIDmode
		       && GET_MODE (SET_SRC (body)) != GET_MODE (memref))
		/* This shouldn't happen because anything that didn't have
		   one of these modes should have got converted explicitly
		   and then referenced through a subreg.
		   This is so because the original bit-field was
		   handled by agg_mode and so its tree structure had
		   the same mode that memref now has.  */
		abort ();
	    }
	  else
	    {
	      rtx dest = SET_DEST (body);

	      while (GET_CODE (dest) == SUBREG
		     && SUBREG_WORD (dest) == 0)
		dest = SUBREG_REG (dest);
	      SET_DEST (body) = dest;

	      memref = adj_offsetable_operand (memref, offset);
	      if (GET_MODE (dest) == GET_MODE (memref))
		SET_SRC (body) = memref;
	      else
		{
		  /* Convert the mem ref to the destination mode.  */
		  rtx last = get_last_insn ();
		  rtx newreg = gen_reg_rtx (GET_MODE (dest));
		  convert_move (newreg, memref,
				GET_CODE (SET_SRC (body)) == ZERO_EXTRACT);
		  /* Put the conversion before the insn being fixed.  */
		  reorder_insns (NEXT_INSN (last), get_last_insn (),
				 PREV_INSN (insn));
		  SET_SRC (body) = newreg;
		}
	    }

	  /* Cause the insn to be re-recognized.  */

	  INSN_CODE (insn) = -1;
	}
    }
}

/* 1 + last pseudo register number used for loading a copy
   of a parameter of this function.  */

static int max_parm_reg;

/* Vector indexed by REGNO, containing location on stack in which
   to put the parm which is nominally in pseudo register REGNO,
   if we discover that that parm must go in the stack.  */
static rtx *parm_reg_stack_loc;

int
max_parm_reg_num ()
{
  return max_parm_reg;
}

/* Return the first insn following those generated by `assign_parms'.  */

rtx
get_first_nonparm_insn ()
{
  if (last_parm_insn)
    return NEXT_INSN (last_parm_insn);
  return get_insns ();
}

/* Get the stack home of a REG rtx that is one of this function's parameters.
   This is called rather than assign a new stack slot as a local.
   Return 0 if there is no existing stack home suitable for such use.  */

static rtx
parm_stack_loc (reg)
     rtx reg;
{
  if (REGNO (reg) < max_parm_reg)
    return parm_reg_stack_loc[REGNO (reg)];
  return 0;
}

/* Assign RTL expressions to the function's parameters.
   This may involve copying them into registers and using
   those registers as the RTL for them.  */

static void
assign_parms (fndecl)
     tree fndecl;
{
  register tree parm;
  register rtx entry_parm;
  register rtx stack_parm;
  register CUMULATIVE_ARGS args_so_far;
  enum machine_mode passed_mode, nominal_mode;
  /* Total space needed so far for args on the stack,
     given as a constant and a tree-expression.  */
  struct args_size stack_args_size;
  int first_parm_offset = FIRST_PARM_OFFSET (fndecl);

  int nparmregs
    = list_length (DECL_ARGUMENTS (fndecl)) + FIRST_PSEUDO_REGISTER;

  /* Nonzero if function takes extra anonymous args.
     This means the last named arg must be on the stack
     right before the anonymous ones.
     Also nonzero if the first arg is named `__builtin_va_alist',
     which is used on some machines for old-fashioned non-ANSI varargs.h;
     this too should be stuck onto the stack as if it had arrived there.  */
  int vararg
    = ((DECL_ARGUMENTS (fndecl) != 0
	&& (! strcmp (IDENTIFIER_POINTER (DECL_NAME (DECL_ARGUMENTS (fndecl))),
		      "__builtin_va_alist")))
       ||
       (TYPE_ARG_TYPES (TREE_TYPE (fndecl)) != 0
	&& (TREE_VALUE (tree_last (TYPE_ARG_TYPES (TREE_TYPE (fndecl))))
	    != void_type_node)));

  stack_args_size.constant = 0;
  stack_args_size.var = 0;

  /* If struct value address comes on the stack, count it in size of args.  */
  if (DECL_MODE (DECL_RESULT (fndecl)) == BLKmode
      && GET_CODE (struct_value_incoming_rtx) == MEM)
    stack_args_size.constant += GET_MODE_SIZE (Pmode);

  parm_reg_stack_loc = (rtx *) oballoc (nparmregs * sizeof (rtx));
  bzero (parm_reg_stack_loc, nparmregs * sizeof (rtx));

  INIT_CUMULATIVE_ARGS (args_so_far, TREE_TYPE (fndecl));

  for (parm = DECL_ARGUMENTS (fndecl); parm; parm = TREE_CHAIN (parm))
    {
      int aggregate
	= (TREE_CODE (TREE_TYPE (parm)) == ARRAY_TYPE
	   || TREE_CODE (TREE_TYPE (parm)) == RECORD_TYPE
	   || TREE_CODE (TREE_TYPE (parm)) == UNION_TYPE);
      struct args_size stack_offset;
      rtx stack_offset_rtx;
      enum direction where_pad;

      DECL_OFFSET (parm) = -1;

      if (TREE_TYPE (parm) == error_mark_node
	  /* This can happen after weird syntax errors
	     or if an enum type is defined among the parms.  */
	  || TREE_CODE (parm) != PARM_DECL
	  || DECL_ARG_TYPE (parm) == NULL)
	{
	  DECL_RTL (parm) = gen_rtx (MEM, BLKmode, const0_rtx);
	  continue;
	}

      /* Find mode of arg as it is passed, and mode of arg
	 as it should be during execution of this function.  */
      passed_mode = TYPE_MODE (DECL_ARG_TYPE (parm));
      nominal_mode = TYPE_MODE (TREE_TYPE (parm));

      /* Get this parm's offset as an rtx.  */
      stack_offset = stack_args_size;
      stack_offset.constant += first_parm_offset;

      /* Find out if the parm needs padding, and whether above or below.  */
      where_pad
	= FUNCTION_ARG_PADDING (passed_mode,
				expand_expr (size_in_bytes (DECL_ARG_TYPE (parm)),
					     0, VOIDmode, 0));

      /* If it is padded below, adjust the stack address
	 upward over the padding.  */
      if (where_pad == downward)
	{
	  if (passed_mode != BLKmode)
	    {
	      if (GET_MODE_BITSIZE (passed_mode) % PARM_BOUNDARY)
		stack_offset.constant
		  += (((GET_MODE_BITSIZE (passed_mode) + PARM_BOUNDARY - 1)
		       / PARM_BOUNDARY * PARM_BOUNDARY / BITS_PER_UNIT)
		      - GET_MODE_SIZE (passed_mode));
	    }
	  else
	    {
	      tree sizetree = size_in_bytes (DECL_ARG_TYPE (parm));
	      /* Round the size up to multiple of PARM_BOUNDARY bits.  */
	      tree s1 = convert_units (sizetree, BITS_PER_UNIT, PARM_BOUNDARY);
	      tree s2 = convert_units (s1, PARM_BOUNDARY, BITS_PER_UNIT);
	      /* Add it in.  */
	      ADD_PARM_SIZE (stack_offset, s2);
	      SUB_PARM_SIZE (stack_offset, sizetree);
	    }
	}

      stack_offset_rtx = ARGS_SIZE_RTX (stack_offset);

      /* Determine parm's home in the stack,
	 in case it arrives in the stack or we should pretend it did.  */
      stack_parm
	= gen_rtx (MEM, passed_mode,
		   memory_address (passed_mode,
				   gen_rtx (PLUS, Pmode,
					    arg_pointer_rtx, stack_offset_rtx)));

      /* If this is a memory ref that contains aggregate components,
	 mark it as such for cse and loop optimize.  */
      MEM_IN_STRUCT_P (stack_parm) = aggregate;

      /* Let machine desc say which reg (if any) the parm arrives in.
	 0 means it arrives on the stack.  */
      entry_parm = 0;
      /* Variable-size args, and args following such, are never in regs.  */
      if (TREE_CODE (TYPE_SIZE (TREE_TYPE (parm))) == INTEGER_CST
	  || stack_offset.var != 0)
	{
#ifdef FUNCTION_INCOMING_ARG
	  entry_parm
	    = FUNCTION_INCOMING_ARG (args_so_far, passed_mode,
				     DECL_ARG_TYPE (parm), 1);
#else
	  entry_parm
	    = FUNCTION_ARG (args_so_far, passed_mode, DECL_ARG_TYPE (parm), 1);
#endif
	}
      /* If this parm was passed part in regs and part in memory,
	 pretend it arrived entirely in memory
	 by pushing the register-part onto the stack.

	 In the special case of a DImode or DFmode that is split,
	 we could put it together in a pseudoreg directly,
	 but for now that's not worth bothering with.  */

      /* If this is the last named arg and anonymous args follow,
	 likewise pretend this arg arrived on the stack
	 so varargs can find the anonymous args following it.  */
      {
	int nregs = 0;
	int i;
#ifdef FUNCTION_ARG_PARTIAL_NREGS
	nregs = FUNCTION_ARG_PARTIAL_NREGS (args_so_far, passed_mode,
					    DECL_ARG_TYPE (parm), 1);
#endif
	if (TREE_CHAIN (parm) == 0 && vararg && entry_parm != 0)
	  {
	    if (GET_MODE (entry_parm) == BLKmode)
	      nregs = GET_MODE_SIZE (GET_MODE (entry_parm)) / UNITS_PER_WORD;
	    else
	      nregs = (int_size_in_bytes (DECL_ARG_TYPE (parm))
		       / UNITS_PER_WORD);
	  }

	if (nregs > 0)
	  {
	    current_function_pretend_args_size
	      = (((nregs * UNITS_PER_WORD) + (PARM_BOUNDARY / BITS_PER_UNIT) - 1)
		 / (PARM_BOUNDARY / BITS_PER_UNIT)
		 * (PARM_BOUNDARY / BITS_PER_UNIT));

	    i = nregs;
	    while (--i >= 0)
	      emit_move_insn (gen_rtx (MEM, SImode,
				       plus_constant (XEXP (stack_parm, 0),
						      i * GET_MODE_SIZE (SImode))),
			      gen_rtx (REG, SImode, REGNO (entry_parm) + i));
	    entry_parm = stack_parm;
	  }
      }

      /* If we didn't decide this parm came in a register,
	 by default it came on the stack.  */
      if (entry_parm == 0)
	entry_parm = stack_parm;

      /* For a stack parm, record in DECL_OFFSET the arglist offset
	 of the parm at the time it is passed (before conversion).  */
      if (entry_parm == stack_parm)
	DECL_OFFSET (parm) = stack_offset.constant * BITS_PER_UNIT;

      /* If there is actually space on the stack for this parm,
	 count it in stack_args_size; otherwise set stack_parm to 0
	 to indicate there is no preallocated stack slot for the parm.  */

      if (entry_parm == stack_parm
#ifdef REG_PARM_STACK_SPACE
	  /* On some machines, even if a parm value arrives in a register
	     there is still an (uninitialized) stack slot allocated for it.  */
	  || 1
#endif
	  )
	{
	  tree sizetree = size_in_bytes (DECL_ARG_TYPE (parm));
	  if (where_pad != none)
	    {
	      /* Round the size up to multiple of PARM_BOUNDARY bits.  */
	      tree s1 = convert_units (sizetree, BITS_PER_UNIT, PARM_BOUNDARY);
	      sizetree = convert_units (s1, PARM_BOUNDARY, BITS_PER_UNIT);
	    }
	  /* Add it in.  */
	  ADD_PARM_SIZE (stack_args_size, sizetree);
	}
      else
	/* No stack slot was pushed for this parm.  */
	stack_parm = 0;

      /* Now adjust STACK_PARM to the mode and precise location
	 where this parameter should live during execution,
	 if we discover that it must live in the stack during execution.
	 To make debuggers happier on big-endian machines, we store
	 the value in the last bytes of the space available.  */

      if (nominal_mode != BLKmode && nominal_mode != passed_mode
	  && stack_parm != 0)
	{
#ifdef BYTES_BIG_ENDIAN
	  if (GET_MODE_SIZE (nominal_mode) < UNITS_PER_WORD)
	    {
	      stack_offset.constant
		+= GET_MODE_SIZE (passed_mode)
		  - GET_MODE_SIZE (nominal_mode);
	      stack_offset_rtx = ARGS_SIZE_RTX (stack_offset);
	    }
#endif

	  stack_parm
	    = gen_rtx (MEM, nominal_mode,
		       memory_address (nominal_mode,
				       gen_rtx (PLUS, Pmode,
						arg_pointer_rtx,
						stack_offset_rtx)));

	  /* If this is a memory ref that contains aggregate components,
	     mark it as such for cse and loop optimize.  */
	  MEM_IN_STRUCT_P (stack_parm) = aggregate;
	}

      /* ENTRY_PARM is an RTX for the parameter as it arrives,
	 in the mode in which it arrives.
	 STACK_PARM is an RTX for a stack slot where the parameter can live
	 during the function (in case we want to put it there).
	 STACK_PARM is 0 if no stack slot was pushed for it.

	 Now output code if necessary to convert ENTRY_PARM to
	 the type in which this function declares it,
	 and store that result in an appropriate place,
	 which may be a pseudo reg, may be STACK_PARM,
	 or may be a local stack slot if STACK_PARM is 0.

	 Set DECL_RTL to that place.  */

      if (nominal_mode == BLKmode)
	{
	  /* If a BLKmode arrives in registers, copy it to a stack slot.  */
	  if (GET_CODE (entry_parm) == REG)
	    {
	      if (stack_parm == 0)
		stack_parm
		  = assign_stack_local (GET_MODE (entry_parm),
					int_size_in_bytes (TREE_TYPE (parm)));

	      move_block_from_reg (REGNO (entry_parm), stack_parm,
				   int_size_in_bytes (TREE_TYPE (parm))
				   / UNITS_PER_WORD);
	    }
	  DECL_RTL (parm) = stack_parm;
	}
      else if (! ((obey_regdecls && ! TREE_REGDECL (parm)
		   && ! TREE_INLINE (fndecl))
		  /* If -ffloat-store specified, don't put explicit
		     float variables into registers.  */
		  || (flag_float_store
		      && TREE_CODE (TREE_TYPE (parm)) == REAL_TYPE)))
	{
	  /* Store the parm in a pseudoregister during the function.  */
	  register rtx parmreg = gen_reg_rtx (nominal_mode);

	  REG_USERVAR_P (parmreg) = 1;
	  DECL_RTL (parm) = parmreg;

	  /* Copy the value into the register.  */
	  if (GET_MODE (parmreg) != GET_MODE (entry_parm))
	    convert_move (parmreg, entry_parm, 0);
	  else
	    emit_move_insn (parmreg, entry_parm);

	  /* In any case, record the parm's desired stack location
	     in case we later discover it must live in the stack.  */
	  if (REGNO (parmreg) >= nparmregs)
	    {
	      rtx *new;
	      nparmregs = REGNO (parmreg) + 5;
	      new = (rtx *) oballoc (nparmregs * sizeof (rtx));
	      bcopy (parm_reg_stack_loc, new, nparmregs * sizeof (rtx));
	      parm_reg_stack_loc = new;
	    }
	  parm_reg_stack_loc[REGNO (parmreg)] = stack_parm;

	  /* Mark the register as eliminable if we did no conversion
	     and it was copied from memory at a fixed offset.  */
	  if (nominal_mode == passed_mode
	      && GET_CODE (entry_parm) == MEM
	      && stack_offset.var == 0)
	    REG_NOTES (get_last_insn ())
	      = gen_rtx (EXPR_LIST, REG_EQUIV,
			 entry_parm, REG_NOTES (get_last_insn ()));

	  /* For pointer data type, suggest pointer register.  */
	  if (TREE_CODE (TREE_TYPE (parm)) == POINTER_TYPE)
	    mark_reg_pointer (parmreg);
	}
      else
	{
	  /* Value must be stored in the stack slot STACK_PARM
	     during function execution.  */

	  if (passed_mode != nominal_mode)
	    /* Conversion is required.  */
	    entry_parm = convert_to_mode (nominal_mode, entry_parm, 0);

	  if (entry_parm != stack_parm)
	    {
	      if (stack_parm == 0)
		stack_parm = assign_stack_local (GET_MODE (entry_parm),
						 GET_MODE_SIZE (GET_MODE (entry_parm)));
	      emit_move_insn (stack_parm, entry_parm);
	    }

	  DECL_RTL (parm) = stack_parm;
	  frame_pointer_needed = 1;
	}
      
      if (TREE_VOLATILE (parm))
	MEM_VOLATILE_P (DECL_RTL (parm)) = 1;
      if (TREE_READONLY (parm))
	RTX_UNCHANGING_P (DECL_RTL (parm)) = 1;

      /* Update info on where next arg arrives in registers.  */

      FUNCTION_ARG_ADVANCE (args_so_far, passed_mode, DECL_ARG_TYPE (parm), 1);
    }

  max_parm_reg = max_reg_num ();
  last_parm_insn = get_last_insn ();

  current_function_args_size = stack_args_size.constant;
}

/* Allocation of space for returned structure values.
   During the rtl generation pass, `get_structure_value_addr'
   is called from time to time to request the address of a block in our
   stack frame in which called functions will store the structures
   they are returning.  The same space is used for all of these blocks.  

   We allocate these blocks like stack locals.  We keep reusing
   the same block until a bigger one is needed.  */

/* Length in bytes of largest structure value returned by
   any function called so far in this function.  */
static int max_structure_value_size;

/* An rtx for the addr we are currently using for structure values.
   This is typically (PLUS (REG:SI stackptr) (CONST_INT...)).  */
static rtx structure_value;

rtx
get_structure_value_addr (sizex)
     rtx sizex;
{
  register int size;
  if (GET_CODE (sizex) != CONST_INT)
    abort ();
  size = INTVAL (sizex);

  /* Round up to a multiple of the main allocation unit.  */
  size = (((size + (BIGGEST_ALIGNMENT / BITS_PER_UNIT) - 1)
	   / (BIGGEST_ALIGNMENT / BITS_PER_UNIT))
	  * (BIGGEST_ALIGNMENT / BITS_PER_UNIT));

  /* If this size is bigger than space we know to use,
     get a bigger piece of space.  */
  if (size > max_structure_value_size)
    {
      max_structure_value_size = size;
      structure_value = assign_stack_local (BLKmode, size);
      if (GET_CODE (structure_value) == MEM)
	structure_value = XEXP (structure_value, 0);
    }

  return structure_value;
}

/* Walk the tree of LET_STMTs describing the binding levels within a function
   and warn about uninitialized variables.
   This is done after calling flow_analysis and before global_alloc
   clobbers the pseudo-regs to hard regs.  */

void
uninitialized_vars_warning (block)
     tree block;
{
  register tree decl, sub;
  for (decl = STMT_VARS (block); decl; decl = TREE_CHAIN (decl))
    {
      if (TREE_CODE (decl) == VAR_DECL
	  /* These warnings are unreliable for and aggregates
	     because assigning the fields one by one can fail to convince
	     flow.c that the entire aggregate was initialized.
	     Unions are troublesome because members may be shorter.  */
	  && TREE_CODE (TREE_TYPE (decl)) != RECORD_TYPE
	  && TREE_CODE (TREE_TYPE (decl)) != UNION_TYPE
	  && TREE_CODE (TREE_TYPE (decl)) != ARRAY_TYPE
	  && GET_CODE (DECL_RTL (decl)) == REG
	  && regno_uninitialized (REGNO (DECL_RTL (decl))))
	warning_with_decl (decl,
			   "variable `%s' used uninitialized in this function");
      if (TREE_CODE (decl) == VAR_DECL
	  && GET_CODE (DECL_RTL (decl)) == REG
	  && regno_clobbered_at_setjmp (REGNO (DECL_RTL (decl))))
	warning_with_decl (decl,
			   "variable `%s' may be clobbered by `longjmp'");
    }
  for (sub = STMT_BODY (block); sub; sub = TREE_CHAIN (sub))
    uninitialized_vars_warning (sub);
}

/* If this function call setjmp, put all vars into the stack
   unless they were declared `register'.  */

void
setjmp_protect (block)
     tree block;
{
  register tree decl, sub;
  for (decl = STMT_VARS (block); decl; decl = TREE_CHAIN (decl))
    if ((TREE_CODE (decl) == VAR_DECL
	 || TREE_CODE (decl) == PARM_DECL)
	&& DECL_RTL (decl) != 0
	&& GET_CODE (DECL_RTL (decl)) == REG
	&& ! TREE_REGDECL (decl))
      put_var_into_stack (decl);
  for (sub = STMT_BODY (block); sub; sub = TREE_CHAIN (sub))
    setjmp_protect (sub);
}

/* Generate RTL for the start of the function FUNC (a FUNCTION_DECL tree node)
   and initialize static variables for generating RTL for the statements
   of the function.  */

void
expand_function_start (subr)
     tree subr;
{
  register int i;
  tree tem;

  this_function = subr;
  cse_not_expected = ! optimize;

  /* We have not yet found a reason why a frame pointer cannot
     be omitted for this function in particular, but maybe we know
     a priori that it is required.
     `flag_omit_frame_pointer' has its main effect here.  */
  frame_pointer_needed = FRAME_POINTER_REQUIRED || ! flag_omit_frame_pointer;

  /* No gotos have been expanded yet.  */
  goto_fixup_chain = 0;

  /* No invalid stack slots have been made yet.  */
  invalid_stack_slot = 0;

  /* Initialize the RTL mechanism.  */
  init_emit (write_symbols);

  /* Initialize the queue of pending postincrement and postdecrements,
     and some other info in expr.c.  */
  init_expr ();

  init_const_rtx_hash_table ();

  /* Decide whether function should try to pop its args on return.  */

  current_function_pops_args = RETURN_POPS_ARGS (TREE_TYPE (subr));

  current_function_name = IDENTIFIER_POINTER (DECL_NAME (subr));

  /* Nonzero if this is a nested function that uses a static chain.  */

  current_function_needs_context = (DECL_CONTEXT (current_function_decl) != 0);

  /* Set if a call to setjmp is seen.  */

  current_function_calls_setjmp = 0;

  /* Nonzero if this function needs an arg saying where to store value.  */
  current_function_returns_struct
    = (DECL_MODE (DECL_RESULT (current_function_decl)) == BLKmode);

  /* Make the label for return statements to jump to, if this machine
     does not have a one-instruction return.  */
#ifdef HAVE_return
  if (HAVE_return)
    return_label = 0;
  else
    return_label = gen_label_rtx ();
#else
  return_label = gen_label_rtx ();
#endif

  /* No space assigned yet for structure values.  */
  max_structure_value_size = 0;
  structure_value = 0;

  /* We are not currently within any block, conditional, loop or case.  */
  block_stack = 0;
  loop_stack = 0;
  case_stack = 0;
  cond_stack = 0;
  nesting_stack = 0;
  nesting_depth = 0;

  /* We have not yet needed to make a label to jump to for tail-recursion.  */
  tail_recursion_label = 0;

  /* No stack slots allocated yet.  */
  frame_offset = STARTING_FRAME_OFFSET;

  /* No SAVE_EXPRs in this function yet.  */
  save_expr_regs = 0;

  /* No RTL_EXPRs in this function yet.  */
  rtl_expr_chain = 0;

  /* Within function body, compute a type's size as soon it is laid out.  */
  immediate_size_expand++;

  init_pending_stack_adjust ();
  clear_current_args_size ();
  current_function_pretend_args_size = 0;

  /* Prevent ever trying to delete the first instruction of a function.
     Also tell final how to output a linenum before the function prologue.  */
  emit_line_note (DECL_SOURCE_FILE (subr), DECL_SOURCE_LINE (subr));
  /* Make sure first insn is a note even if we don't want linenums.
     This makes sure the first insn will never be deleted.
     Also, final expects a note to appear there.  */
  emit_note (0, NOTE_INSN_DELETED);

  /* Initialize rtx for parameters and local variables.
     In some cases this requires emitting insns.  */

  assign_parms (subr);

  /* Initialize rtx used to return the value.  */

  if (DECL_MODE (DECL_RESULT (subr)) == BLKmode)
    {
      /* Returning something that won't go in a register.  */
      register rtx value_address;

      /* Expect to be passed the address of a place to store the value.  */
      value_address = gen_reg_rtx (Pmode);
      emit_move_insn (value_address, struct_value_incoming_rtx);
      DECL_RTL (DECL_RESULT (subr))
	= gen_rtx (MEM, DECL_MODE (DECL_RESULT (subr)),
		   value_address);
    }
  else
#ifdef FUNCTION_OUTGOING_VALUE
    DECL_RTL (DECL_RESULT (subr))
      = FUNCTION_OUTGOING_VALUE (TREE_TYPE (DECL_RESULT (subr)), subr);
#else
    DECL_RTL (DECL_RESULT (subr))
      = FUNCTION_VALUE (TREE_TYPE (DECL_RESULT (subr)), subr);
#endif

  /* Mark this reg as the function's return value.  */
  if (GET_CODE (DECL_RTL (DECL_RESULT (subr))) == REG)
    REG_FUNCTION_VALUE_P (DECL_RTL (DECL_RESULT (subr))) = 1;

  /* If doing stupid allocation, mark parms as born here.  */

  if (obey_regdecls)
    {
      parm_birth_insn = get_last_insn ();
      for (i = FIRST_PSEUDO_REGISTER; i < max_parm_reg; i++)
	use_variable (regno_reg_rtx[i]);
    }

  /* After the parm initializations is where the tail-recursion label
     should go, if we end up needing one.  */
  tail_recursion_reentry = get_last_insn ();

  /* Evaluate now the sizes of any types declared among the arguments.  */
  for (tem = get_pending_sizes (); tem; tem = TREE_CHAIN (tem))
    expand_expr (TREE_VALUE (tem), 0, VOIDmode, 0);
}

/* Generate RTL for the end of the current function.
   LINE is the line number.  */

void
expand_function_end (filename, line)
     char *filename;
     int line;
{
  register int i;

  /* Outside function body, can't compute type's actual size
     until next function's body starts.  */
  immediate_size_expand--;

  /* If doing stupid register allocation,
     mark register parms as dying here.  */

  if (obey_regdecls)
    {
      rtx tem;
      for (i = FIRST_PSEUDO_REGISTER; i < max_parm_reg; i++)
	use_variable (regno_reg_rtx[i]);

      /* Likewise for the regs of all the SAVE_EXPRs in the function.  */

      for (tem = save_expr_regs; tem; tem = XEXP (tem, 1))
	use_variable (XEXP (tem, 0));

      /* Also mark those as borm at the beginning of the function.
	 (This was done in expand_function_start for parms).  */
      for (tem = save_expr_regs; tem; tem = XEXP (tem, 1))
	emit_insn_after (gen_rtx (USE, VOIDmode, XEXP (tem, 0)),
			 parm_birth_insn);
    }

  clear_pending_stack_adjust ();
  do_pending_stack_adjust ();

  /* Mark the end of the function body.
     If control reaches this insn, the function can drop through
     without returning a value.  */
  emit_note (0, NOTE_INSN_FUNCTION_END);

  /* Output a linenumber for the end of the function.
     SDB depends on this.  */
  emit_line_note_force (input_filename, line);

  /* If we require a true epilogue,
     put here the label that return statements jump to.
     If there will be no epilogue, write a return instruction.  */
#ifdef HAVE_return
  if (HAVE_return)
    emit_jump_insn (gen_return ());
  else
#endif
    emit_label (return_label);

  /* Fix up any gotos that jumped out to the outermost
     binding level of the function.
     Must follow emitting RETURN_LABEL.  */

  /* If you have any cleanups to do at this point,
     and they need to create temporary variables,
     then you will lose.  */
  fixup_gotos (0, 0, get_insns (), 0);
}


