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

/* Gimple IR support functions.

   Copyright 2007, 2008 Free Software Foundation, Inc.
   Contributed by Aldy Hernandez <aldyh@redhat.com>

This file is part of GCC.

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

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

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

#include "config.h"
#include "system.h"
#include "coretypes.h"
#include "tm.h"
#include "tree.h"
#include "ggc.h"
#include "errors.h"
#include "hard-reg-set.h"
#include "basic-block.h"
#include "gimple.h"
#include "diagnostic.h"
#include "tree-flow.h"
#include "value-prof.h"
#include "flags.h"

#define DEFGSCODE(SYM, NAME, STRUCT)    NAME,
const char *const gimple_code_name[] = {
#include "gimple.def"
};
#undef DEFGSCODE

/* All the tuples have their operand vector at the very bottom
   of the structure.  Therefore, the offset required to find the
   operands vector the size of the structure minus the size of the 1
   element tree array at the end (see gimple_ops).  */
#define DEFGSCODE(SYM, NAME, STRUCT)    (sizeof (STRUCT) - sizeof (tree)),
const size_t gimple_ops_offset_[] = {
#include "gimple.def"
};
#undef DEFGSCODE

#ifdef GATHER_STATISTICS
/* Gimple stats.  */

int gimple_alloc_counts[(int) gimple_alloc_kind_all];
int gimple_alloc_sizes[(int) gimple_alloc_kind_all];

/* Keep in sync with gimple.h:enum gimple_alloc_kind.  */
static const char * const gimple_alloc_kind_names[] = {
    "assignments",
    "phi nodes",
    "conditionals",
    "sequences",
    "everything else"
};

#endif /* GATHER_STATISTICS */

/* A cache of gimple_seq objects.  Sequences are created and destroyed
   fairly often during gimplification.  */
static GTY ((deletable)) struct gimple_seq_d *gimple_seq_cache;

/* Private API manipulation functions shared only with some
   other files.  */
extern void gimple_set_stored_syms (gimple, bitmap, bitmap_obstack *);
extern void gimple_set_loaded_syms (gimple, bitmap, bitmap_obstack *);

/* Gimple tuple constructors.
   Note: Any constructor taking a ``gimple_seq'' as a parameter, can
   be passed a NULL to start with an empty sequence.  */

/* Set the code for statement G to CODE.  */

static inline void
gimple_set_code (gimple g, enum gimple_code code)
{
  g->gsbase.code = code;
}


/* Return the GSS_* identifier for the given GIMPLE statement CODE.  */

static enum gimple_statement_structure_enum
gss_for_code (enum gimple_code code)
{
  switch (code)
    {
    case GIMPLE_ASSIGN:
    case GIMPLE_CALL:
    case GIMPLE_RETURN:                 return GSS_WITH_MEM_OPS;
    case GIMPLE_COND:
    case GIMPLE_GOTO:
    case GIMPLE_LABEL:
    case GIMPLE_CHANGE_DYNAMIC_TYPE:
    case GIMPLE_SWITCH:                 return GSS_WITH_OPS;
    case GIMPLE_ASM:                    return GSS_ASM;
    case GIMPLE_BIND:                   return GSS_BIND;
    case GIMPLE_CATCH:                  return GSS_CATCH;
    case GIMPLE_EH_FILTER:              return GSS_EH_FILTER;
    case GIMPLE_NOP:                    return GSS_BASE;
    case GIMPLE_PHI:                    return GSS_PHI;
    case GIMPLE_RESX:                   return GSS_RESX;
    case GIMPLE_TRY:                    return GSS_TRY;
    case GIMPLE_WITH_CLEANUP_EXPR:      return GSS_WCE;
    case GIMPLE_OMP_CRITICAL:           return GSS_OMP_CRITICAL;
    case GIMPLE_OMP_FOR:                return GSS_OMP_FOR;
    case GIMPLE_OMP_MASTER:             
    case GIMPLE_OMP_ORDERED:
    case GIMPLE_OMP_SECTION:            return GSS_OMP;
    case GIMPLE_OMP_RETURN:
    case GIMPLE_OMP_SECTIONS_SWITCH:    return GSS_BASE;
    case GIMPLE_OMP_CONTINUE:           return GSS_OMP_CONTINUE;
    case GIMPLE_OMP_PARALLEL:           return GSS_OMP_PARALLEL;
    case GIMPLE_OMP_TASK:               return GSS_OMP_TASK;
    case GIMPLE_OMP_SECTIONS:           return GSS_OMP_SECTIONS;
    case GIMPLE_OMP_SINGLE:             return GSS_OMP_SINGLE;
    case GIMPLE_OMP_ATOMIC_LOAD:        return GSS_OMP_ATOMIC_LOAD;
    case GIMPLE_OMP_ATOMIC_STORE:       return GSS_OMP_ATOMIC_STORE;
    case GIMPLE_PREDICT:                return GSS_BASE;
    default:                            gcc_unreachable ();
    }
}


/* Return the number of bytes needed to hold a GIMPLE statement with
   code CODE.  */

static size_t
gimple_size (enum gimple_code code)
{
  enum gimple_statement_structure_enum gss = gss_for_code (code);

  if (gss == GSS_WITH_OPS)
    return sizeof (struct gimple_statement_with_ops);
  else if (gss == GSS_WITH_MEM_OPS)
    return sizeof (struct gimple_statement_with_memory_ops);

  switch (code)
    {
    case GIMPLE_ASM:
      return sizeof (struct gimple_statement_asm);
    case GIMPLE_NOP:
      return sizeof (struct gimple_statement_base);
    case GIMPLE_BIND:
      return sizeof (struct gimple_statement_bind);
    case GIMPLE_CATCH:
      return sizeof (struct gimple_statement_catch);
    case GIMPLE_EH_FILTER:
      return sizeof (struct gimple_statement_eh_filter);
    case GIMPLE_TRY:
      return sizeof (struct gimple_statement_try);
    case GIMPLE_RESX:
      return sizeof (struct gimple_statement_resx);
    case GIMPLE_OMP_CRITICAL:
      return sizeof (struct gimple_statement_omp_critical);
    case GIMPLE_OMP_FOR:
      return sizeof (struct gimple_statement_omp_for);
    case GIMPLE_OMP_PARALLEL:
      return sizeof (struct gimple_statement_omp_parallel);
    case GIMPLE_OMP_TASK:
      return sizeof (struct gimple_statement_omp_task);
    case GIMPLE_OMP_SECTION:
    case GIMPLE_OMP_MASTER:
    case GIMPLE_OMP_ORDERED:
      return sizeof (struct gimple_statement_omp);
    case GIMPLE_OMP_RETURN:
      return sizeof (struct gimple_statement_base);
    case GIMPLE_OMP_CONTINUE:
      return sizeof (struct gimple_statement_omp_continue);
    case GIMPLE_OMP_SECTIONS:
      return sizeof (struct gimple_statement_omp_sections);
    case GIMPLE_OMP_SECTIONS_SWITCH:
      return sizeof (struct gimple_statement_base);
    case GIMPLE_OMP_SINGLE:
      return sizeof (struct gimple_statement_omp_single);
    case GIMPLE_OMP_ATOMIC_LOAD:
      return sizeof (struct gimple_statement_omp_atomic_load);
    case GIMPLE_OMP_ATOMIC_STORE:
      return sizeof (struct gimple_statement_omp_atomic_store);
    case GIMPLE_WITH_CLEANUP_EXPR:
      return sizeof (struct gimple_statement_wce);
    case GIMPLE_CHANGE_DYNAMIC_TYPE:
      return sizeof (struct gimple_statement_with_ops);
    case GIMPLE_PREDICT:
      return sizeof (struct gimple_statement_base);
    default:
      break;
    }

  gcc_unreachable ();
}


/* Allocate memory for a GIMPLE statement with code CODE and NUM_OPS
   operands.  */

#define gimple_alloc(c, n) gimple_alloc_stat (c, n MEM_STAT_INFO)
static gimple
gimple_alloc_stat (enum gimple_code code, unsigned num_ops MEM_STAT_DECL)
{
  size_t size;
  gimple stmt;

  size = gimple_size (code);
  if (num_ops > 0)
    size += sizeof (tree) * (num_ops - 1);

#ifdef GATHER_STATISTICS
  {
    enum gimple_alloc_kind kind = gimple_alloc_kind (code);
    gimple_alloc_counts[(int) kind]++;
    gimple_alloc_sizes[(int) kind] += size;
  }
#endif

  stmt = (gimple) ggc_alloc_cleared_stat (size PASS_MEM_STAT);
  gimple_set_code (stmt, code);
  gimple_set_num_ops (stmt, num_ops);

  /* Do not call gimple_set_modified here as it has other side
     effects and this tuple is still not completely built.  */
  stmt->gsbase.modified = 1;

  return stmt;
}

/* Set SUBCODE to be the code of the expression computed by statement G.  */

static inline void
gimple_set_subcode (gimple g, unsigned subcode)
{
  /* We only have 16 bits for the RHS code.  Assert that we are not
     overflowing it.  */
  gcc_assert (subcode < (1 << 16));
  g->gsbase.subcode = subcode;
}



/* Build a tuple with operands.  CODE is the statement to build (which
   must be one of the GIMPLE_WITH_OPS tuples).  SUBCODE is the sub-code
   for the new tuple.  NUM_OPS is the number of operands to allocate.  */ 

#define gimple_build_with_ops(c, s, n) \
  gimple_build_with_ops_stat (c, s, n MEM_STAT_INFO)

static gimple
gimple_build_with_ops_stat (enum gimple_code code, enum tree_code subcode,
                            unsigned num_ops MEM_STAT_DECL)
{
  gimple s = gimple_alloc_stat (code, num_ops PASS_MEM_STAT);
  gimple_set_subcode (s, subcode);

  return s;
}


/* Build a GIMPLE_RETURN statement returning RETVAL.  */

gimple
gimple_build_return (tree retval)
{
  gimple s = gimple_build_with_ops (GIMPLE_RETURN, 0, 1);
  if (retval)
    gimple_return_set_retval (s, retval);
  return s;
}

/* Helper for gimple_build_call, gimple_build_call_vec and
   gimple_build_call_from_tree.  Build the basic components of a
   GIMPLE_CALL statement to function FN with NARGS arguments.  */

static inline gimple
gimple_build_call_1 (tree fn, unsigned nargs)
{
  gimple s = gimple_build_with_ops (GIMPLE_CALL, 0, nargs + 3);
  if (TREE_CODE (fn) == FUNCTION_DECL)
    fn = build_fold_addr_expr (fn);
  gimple_set_op (s, 1, fn);
  return s;
}


/* Build a GIMPLE_CALL statement to function FN with the arguments
   specified in vector ARGS.  */

gimple
gimple_build_call_vec (tree fn, VEC(tree, heap) *args)
{
  unsigned i;
  unsigned nargs = VEC_length (tree, args);
  gimple call = gimple_build_call_1 (fn, nargs);

  for (i = 0; i < nargs; i++)
    gimple_call_set_arg (call, i, VEC_index (tree, args, i));

  return call;
}


/* Build a GIMPLE_CALL statement to function FN.  NARGS is the number of
   arguments.  The ... are the arguments.  */

gimple
gimple_build_call (tree fn, unsigned nargs, ...)
{
  va_list ap;
  gimple call;
  unsigned i;

  gcc_assert (TREE_CODE (fn) == FUNCTION_DECL || is_gimple_call_addr (fn));

  call = gimple_build_call_1 (fn, nargs);

  va_start (ap, nargs);
  for (i = 0; i < nargs; i++)
    gimple_call_set_arg (call, i, va_arg (ap, tree));
  va_end (ap);

  return call;
}


/* Build a GIMPLE_CALL statement from CALL_EXPR T.  Note that T is
   assumed to be in GIMPLE form already.  Minimal checking is done of
   this fact.  */

gimple
gimple_build_call_from_tree (tree t)
{
  unsigned i, nargs;
  gimple call;
  tree fndecl = get_callee_fndecl (t);

  gcc_assert (TREE_CODE (t) == CALL_EXPR);

  nargs = call_expr_nargs (t);
  call = gimple_build_call_1 (fndecl ? fndecl : CALL_EXPR_FN (t), nargs);

  for (i = 0; i < nargs; i++)
    gimple_call_set_arg (call, i, CALL_EXPR_ARG (t, i));

  gimple_set_block (call, TREE_BLOCK (t));

  /* Carry all the CALL_EXPR flags to the new GIMPLE_CALL.  */
  gimple_call_set_chain (call, CALL_EXPR_STATIC_CHAIN (t));
  gimple_call_set_tail (call, CALL_EXPR_TAILCALL (t));
  gimple_call_set_cannot_inline (call, CALL_CANNOT_INLINE_P (t));
  gimple_call_set_return_slot_opt (call, CALL_EXPR_RETURN_SLOT_OPT (t));
  gimple_call_set_from_thunk (call, CALL_FROM_THUNK_P (t));
  gimple_call_set_va_arg_pack (call, CALL_EXPR_VA_ARG_PACK (t));

  return call;
}


/* Extract the operands and code for expression EXPR into *SUBCODE_P,
   *OP1_P and *OP2_P respectively.  */

void
extract_ops_from_tree (tree expr, enum tree_code *subcode_p, tree *op1_p,
                       tree *op2_p)
{
  enum gimple_rhs_class grhs_class;

  *subcode_p = TREE_CODE (expr);
  grhs_class = get_gimple_rhs_class (*subcode_p);

  if (grhs_class == GIMPLE_BINARY_RHS)
    {
      *op1_p = TREE_OPERAND (expr, 0);
      *op2_p = TREE_OPERAND (expr, 1);
    }
  else if (grhs_class == GIMPLE_UNARY_RHS)
    {
      *op1_p = TREE_OPERAND (expr, 0);
      *op2_p = NULL_TREE;
    }
  else if (grhs_class == GIMPLE_SINGLE_RHS)
    {
      *op1_p = expr;
      *op2_p = NULL_TREE;
    }
  else
    gcc_unreachable ();
}


/* Build a GIMPLE_ASSIGN statement.

   LHS of the assignment.
   RHS of the assignment which can be unary or binary.  */

gimple
gimple_build_assign_stat (tree lhs, tree rhs MEM_STAT_DECL)
{
  enum tree_code subcode;
  tree op1, op2;

  extract_ops_from_tree (rhs, &subcode, &op1, &op2);
  return gimple_build_assign_with_ops_stat (subcode, lhs, op1, op2
                                            PASS_MEM_STAT);
}


/* Build a GIMPLE_ASSIGN statement with sub-code SUBCODE and operands
   OP1 and OP2.  If OP2 is NULL then SUBCODE must be of class
   GIMPLE_UNARY_RHS or GIMPLE_SINGLE_RHS.  */

gimple
gimple_build_assign_with_ops_stat (enum tree_code subcode, tree lhs, tree op1,
                                   tree op2 MEM_STAT_DECL)
{
  unsigned num_ops;
  gimple p;

  /* Need 1 operand for LHS and 1 or 2 for the RHS (depending on the
     code).  */
  num_ops = get_gimple_rhs_num_ops (subcode) + 1;
  
  p = gimple_build_with_ops_stat (GIMPLE_ASSIGN, subcode, num_ops
                                  PASS_MEM_STAT);
  gimple_assign_set_lhs (p, lhs);
  gimple_assign_set_rhs1 (p, op1);
  if (op2)
    {
      gcc_assert (num_ops > 2);
      gimple_assign_set_rhs2 (p, op2);
    }

  return p;
}


/* Build a new GIMPLE_ASSIGN tuple and append it to the end of *SEQ_P.

   DST/SRC are the destination and source respectively.  You can pass
   ungimplified trees in DST or SRC, in which case they will be
   converted to a gimple operand if necessary.

   This function returns the newly created GIMPLE_ASSIGN tuple.  */

inline gimple
gimplify_assign (tree dst, tree src, gimple_seq *seq_p)
{ 
  tree t = build2 (MODIFY_EXPR, TREE_TYPE (dst), dst, src);
  gimplify_and_add (t, seq_p);
  ggc_free (t);
  return gimple_seq_last_stmt (*seq_p);
}


/* Build a GIMPLE_COND statement.

   PRED is the condition used to compare LHS and the RHS.
   T_LABEL is the label to jump to if the condition is true.
   F_LABEL is the label to jump to otherwise.  */

gimple
gimple_build_cond (enum tree_code pred_code, tree lhs, tree rhs,
                   tree t_label, tree f_label)
{
  gimple p;

  gcc_assert (TREE_CODE_CLASS (pred_code) == tcc_comparison);
  p = gimple_build_with_ops (GIMPLE_COND, pred_code, 4);
  gimple_cond_set_lhs (p, lhs);
  gimple_cond_set_rhs (p, rhs);
  gimple_cond_set_true_label (p, t_label);
  gimple_cond_set_false_label (p, f_label);
  return p;
}


/* Extract operands for a GIMPLE_COND statement out of COND_EXPR tree COND.  */

void
gimple_cond_get_ops_from_tree (tree cond, enum tree_code *code_p,
                               tree *lhs_p, tree *rhs_p)
{
  gcc_assert (TREE_CODE_CLASS (TREE_CODE (cond)) == tcc_comparison
              || TREE_CODE (cond) == TRUTH_NOT_EXPR
              || is_gimple_min_invariant (cond)
              || SSA_VAR_P (cond));

  extract_ops_from_tree (cond, code_p, lhs_p, rhs_p);

  /* Canonicalize conditionals of the form 'if (!VAL)'.  */
  if (*code_p == TRUTH_NOT_EXPR)
    {
      *code_p = EQ_EXPR;
      gcc_assert (*lhs_p && *rhs_p == NULL_TREE);
      *rhs_p = fold_convert (TREE_TYPE (*lhs_p), integer_zero_node);
    }
  /* Canonicalize conditionals of the form 'if (VAL)'  */
  else if (TREE_CODE_CLASS (*code_p) != tcc_comparison)
    {
      *code_p = NE_EXPR;
      gcc_assert (*lhs_p && *rhs_p == NULL_TREE);
      *rhs_p = fold_convert (TREE_TYPE (*lhs_p), integer_zero_node);
    }
}


/* Build a GIMPLE_COND statement from the conditional expression tree
   COND.  T_LABEL and F_LABEL are as in gimple_build_cond.  */

gimple
gimple_build_cond_from_tree (tree cond, tree t_label, tree f_label)
{
  enum tree_code code;
  tree lhs, rhs;

  gimple_cond_get_ops_from_tree (cond, &code, &lhs, &rhs);
  return gimple_build_cond (code, lhs, rhs, t_label, f_label);
}

/* Set code, lhs, and rhs of a GIMPLE_COND from a suitable
   boolean expression tree COND.  */

void
gimple_cond_set_condition_from_tree (gimple stmt, tree cond)
{
  enum tree_code code;
  tree lhs, rhs;

  gimple_cond_get_ops_from_tree (cond, &code, &lhs, &rhs);
  gimple_cond_set_condition (stmt, code, lhs, rhs);
}

/* Build a GIMPLE_LABEL statement for LABEL.  */

gimple
gimple_build_label (tree label)
{
  gimple p = gimple_build_with_ops (GIMPLE_LABEL, 0, 1);
  gimple_label_set_label (p, label);
  return p;
}

/* Build a GIMPLE_GOTO statement to label DEST.  */

gimple
gimple_build_goto (tree dest)
{
  gimple p = gimple_build_with_ops (GIMPLE_GOTO, 0, 1);
  gimple_goto_set_dest (p, dest);
  return p;
}


/* Build a GIMPLE_NOP statement.  */

gimple 
gimple_build_nop (void)
{
  return gimple_alloc (GIMPLE_NOP, 0);
}


/* Build a GIMPLE_BIND statement.
   VARS are the variables in BODY.
   BLOCK is the containing block.  */

gimple
gimple_build_bind (tree vars, gimple_seq body, tree block)
{
  gimple p = gimple_alloc (GIMPLE_BIND, 0);
  gimple_bind_set_vars (p, vars);
  if (body)
    gimple_bind_set_body (p, body);
  if (block)
    gimple_bind_set_block (p, block);
  return p;
}

/* Helper function to set the simple fields of a asm stmt.

   STRING is a pointer to a string that is the asm blocks assembly code.
   NINPUT is the number of register inputs.
   NOUTPUT is the number of register outputs.
   NCLOBBERS is the number of clobbered registers.
   */

static inline gimple
gimple_build_asm_1 (const char *string, unsigned ninputs, unsigned noutputs, 
                    unsigned nclobbers)
{
  gimple p;
  int size = strlen (string);

  p = gimple_build_with_ops (GIMPLE_ASM, 0, ninputs + noutputs + nclobbers);

  p->gimple_asm.ni = ninputs;
  p->gimple_asm.no = noutputs;
  p->gimple_asm.nc = nclobbers;
  p->gimple_asm.string = ggc_alloc_string (string, size);

#ifdef GATHER_STATISTICS
  gimple_alloc_sizes[(int) gimple_alloc_kind (GIMPLE_ASM)] += size;
#endif
  
  return p;
}

/* Build a GIMPLE_ASM statement.

   STRING is the assembly code.
   NINPUT is the number of register inputs.
   NOUTPUT is the number of register outputs.
   NCLOBBERS is the number of clobbered registers.
   INPUTS is a vector of the input register parameters.
   OUTPUTS is a vector of the output register parameters.
   CLOBBERS is a vector of the clobbered register parameters.  */

gimple
gimple_build_asm_vec (const char *string, VEC(tree,gc)* inputs, 
                      VEC(tree,gc)* outputs, VEC(tree,gc)* clobbers)
{
  gimple p;
  unsigned i;

  p = gimple_build_asm_1 (string,
                          VEC_length (tree, inputs),
                          VEC_length (tree, outputs), 
                          VEC_length (tree, clobbers));
  
  for (i = 0; i < VEC_length (tree, inputs); i++)
    gimple_asm_set_input_op (p, i, VEC_index (tree, inputs, i));

  for (i = 0; i < VEC_length (tree, outputs); i++)
    gimple_asm_set_output_op (p, i, VEC_index (tree, outputs, i));

  for (i = 0; i < VEC_length (tree, clobbers); i++)
    gimple_asm_set_clobber_op (p, i, VEC_index (tree, clobbers, i));
  
  return p;
}

/* Build a GIMPLE_ASM statement.

   STRING is the assembly code.
   NINPUT is the number of register inputs.
   NOUTPUT is the number of register outputs.
   NCLOBBERS is the number of clobbered registers.
   ... are trees for each input, output and clobbered register.  */

gimple
gimple_build_asm (const char *string, unsigned ninputs, unsigned noutputs, 
                  unsigned nclobbers, ...)
{
  gimple p;
  unsigned i;
  va_list ap;
  
  p = gimple_build_asm_1 (string, ninputs, noutputs, nclobbers);
  
  va_start (ap, nclobbers);

  for (i = 0; i < ninputs; i++)
    gimple_asm_set_input_op (p, i, va_arg (ap, tree));

  for (i = 0; i < noutputs; i++)
    gimple_asm_set_output_op (p, i, va_arg (ap, tree));

  for (i = 0; i < nclobbers; i++)
    gimple_asm_set_clobber_op (p, i, va_arg (ap, tree));

  va_end (ap);
  
  return p;
}

/* Build a GIMPLE_CATCH statement.

  TYPES are the catch types.
  HANDLER is the exception handler.  */

gimple
gimple_build_catch (tree types, gimple_seq handler)
{
  gimple p = gimple_alloc (GIMPLE_CATCH, 0);
  gimple_catch_set_types (p, types);
  if (handler)
    gimple_catch_set_handler (p, handler);

  return p;
}

/* Build a GIMPLE_EH_FILTER statement.

   TYPES are the filter's types.
   FAILURE is the filter's failure action.  */

gimple
gimple_build_eh_filter (tree types, gimple_seq failure)
{
  gimple p = gimple_alloc (GIMPLE_EH_FILTER, 0);
  gimple_eh_filter_set_types (p, types);
  if (failure)
    gimple_eh_filter_set_failure (p, failure);

  return p;
}

/* Build a GIMPLE_TRY statement.

   EVAL is the expression to evaluate.
   CLEANUP is the cleanup expression.
   KIND is either GIMPLE_TRY_CATCH or GIMPLE_TRY_FINALLY depending on
   whether this is a try/catch or a try/finally respectively.  */

gimple
gimple_build_try (gimple_seq eval, gimple_seq cleanup,
                  enum gimple_try_flags kind)
{
  gimple p;

  gcc_assert (kind == GIMPLE_TRY_CATCH || kind == GIMPLE_TRY_FINALLY);
  p = gimple_alloc (GIMPLE_TRY, 0);
  gimple_set_subcode (p, kind);
  if (eval)
    gimple_try_set_eval (p, eval);
  if (cleanup)
    gimple_try_set_cleanup (p, cleanup);

  return p;
}

/* Construct a GIMPLE_WITH_CLEANUP_EXPR statement.

   CLEANUP is the cleanup expression.  */

gimple
gimple_build_wce (gimple_seq cleanup)
{
  gimple p = gimple_alloc (GIMPLE_WITH_CLEANUP_EXPR, 0);
  if (cleanup)
    gimple_wce_set_cleanup (p, cleanup);

  return p;
}


/* Build a GIMPLE_RESX statement.

   REGION is the region number from which this resx causes control flow to 
   leave.  */

gimple
gimple_build_resx (int region)
{
  gimple p = gimple_alloc (GIMPLE_RESX, 0);
  gimple_resx_set_region (p, region);
  return p;
}


/* The helper for constructing a gimple switch statement.
   INDEX is the switch's index.
   NLABELS is the number of labels in the switch excluding the default.
   DEFAULT_LABEL is the default label for the switch statement.  */

static inline gimple 
gimple_build_switch_1 (unsigned nlabels, tree index, tree default_label)
{
  /* nlabels + 1 default label + 1 index.  */
  gimple p = gimple_build_with_ops (GIMPLE_SWITCH, 0, nlabels + 1 + 1);
  gimple_switch_set_index (p, index);
  gimple_switch_set_default_label (p, default_label);
  return p;
}


/* Build a GIMPLE_SWITCH statement.

   INDEX is the switch's index.
   NLABELS is the number of labels in the switch excluding the DEFAULT_LABEL. 
   ... are the labels excluding the default.  */

gimple 
gimple_build_switch (unsigned nlabels, tree index, tree default_label, ...)
{
  va_list al;
  unsigned i;
  gimple p;
  
  p = gimple_build_switch_1 (nlabels, index, default_label);

  /* Store the rest of the labels.  */
  va_start (al, default_label);
  for (i = 1; i <= nlabels; i++)
    gimple_switch_set_label (p, i, va_arg (al, tree));
  va_end (al);

  return p;
}


/* Build a GIMPLE_SWITCH statement.

   INDEX is the switch's index.
   DEFAULT_LABEL is the default label
   ARGS is a vector of labels excluding the default.  */

gimple
gimple_build_switch_vec (tree index, tree default_label, VEC(tree, heap) *args)
{
  unsigned i;
  unsigned nlabels = VEC_length (tree, args);
  gimple p = gimple_build_switch_1 (nlabels, index, default_label);

  /*  Put labels in labels[1 - (nlabels + 1)].
     Default label is in labels[0].  */
  for (i = 1; i <= nlabels; i++)
    gimple_switch_set_label (p, i, VEC_index (tree, args, i - 1));

  return p;
}


/* Build a GIMPLE_OMP_CRITICAL statement.

   BODY is the sequence of statements for which only one thread can execute.
   NAME is optional identifier for this critical block.  */

gimple 
gimple_build_omp_critical (gimple_seq body, tree name)
{
  gimple p = gimple_alloc (GIMPLE_OMP_CRITICAL, 0);
  gimple_omp_critical_set_name (p, name);
  if (body)
    gimple_omp_set_body (p, body);

  return p;
}

/* Build a GIMPLE_OMP_FOR statement.

   BODY is sequence of statements inside the for loop.
   CLAUSES, are any of the OMP loop construct's clauses: private, firstprivate, 
   lastprivate, reductions, ordered, schedule, and nowait.
   COLLAPSE is the collapse count.
   PRE_BODY is the sequence of statements that are loop invariant.  */

gimple
gimple_build_omp_for (gimple_seq body, tree clauses, size_t collapse,
                      gimple_seq pre_body)
{
  gimple p = gimple_alloc (GIMPLE_OMP_FOR, 0);
  if (body)
    gimple_omp_set_body (p, body);
  gimple_omp_for_set_clauses (p, clauses);
  p->gimple_omp_for.collapse = collapse;
  p->gimple_omp_for.iter = GGC_CNEWVEC (struct gimple_omp_for_iter, collapse);
  if (pre_body)
    gimple_omp_for_set_pre_body (p, pre_body);

  return p;
}


/* Build a GIMPLE_OMP_PARALLEL statement.

   BODY is sequence of statements which are executed in parallel.
   CLAUSES, are the OMP parallel construct's clauses.
   CHILD_FN is the function created for the parallel threads to execute.
   DATA_ARG are the shared data argument(s).  */

gimple 
gimple_build_omp_parallel (gimple_seq body, tree clauses, tree child_fn, 
                           tree data_arg)
{
  gimple p = gimple_alloc (GIMPLE_OMP_PARALLEL, 0);
  if (body)
    gimple_omp_set_body (p, body);
  gimple_omp_parallel_set_clauses (p, clauses);
  gimple_omp_parallel_set_child_fn (p, child_fn);
  gimple_omp_parallel_set_data_arg (p, data_arg);

  return p;
}


/* Build a GIMPLE_OMP_TASK statement.

   BODY is sequence of statements which are executed by the explicit task.
   CLAUSES, are the OMP parallel construct's clauses.
   CHILD_FN is the function created for the parallel threads to execute.
   DATA_ARG are the shared data argument(s).
   COPY_FN is the optional function for firstprivate initialization.
   ARG_SIZE and ARG_ALIGN are size and alignment of the data block.  */

gimple 
gimple_build_omp_task (gimple_seq body, tree clauses, tree child_fn,
                       tree data_arg, tree copy_fn, tree arg_size,
                       tree arg_align)
{
  gimple p = gimple_alloc (GIMPLE_OMP_TASK, 0);
  if (body)
    gimple_omp_set_body (p, body);
  gimple_omp_task_set_clauses (p, clauses);
  gimple_omp_task_set_child_fn (p, child_fn);
  gimple_omp_task_set_data_arg (p, data_arg);
  gimple_omp_task_set_copy_fn (p, copy_fn);
  gimple_omp_task_set_arg_size (p, arg_size);
  gimple_omp_task_set_arg_align (p, arg_align);

  return p;
}


/* Build a GIMPLE_OMP_SECTION statement for a sections statement.

   BODY is the sequence of statements in the section.  */

gimple
gimple_build_omp_section (gimple_seq body)
{
  gimple p = gimple_alloc (GIMPLE_OMP_SECTION, 0);
  if (body)
    gimple_omp_set_body (p, body);

  return p;
}


/* Build a GIMPLE_OMP_MASTER statement.

   BODY is the sequence of statements to be executed by just the master.  */

gimple 
gimple_build_omp_master (gimple_seq body)
{
  gimple p = gimple_alloc (GIMPLE_OMP_MASTER, 0);
  if (body)
    gimple_omp_set_body (p, body);

  return p;
}


/* Build a GIMPLE_OMP_CONTINUE statement.

   CONTROL_DEF is the definition of the control variable.
   CONTROL_USE is the use of the control variable.  */

gimple 
gimple_build_omp_continue (tree control_def, tree control_use)
{
  gimple p = gimple_alloc (GIMPLE_OMP_CONTINUE, 0);
  gimple_omp_continue_set_control_def (p, control_def);
  gimple_omp_continue_set_control_use (p, control_use);
  return p;
}

/* Build a GIMPLE_OMP_ORDERED statement.

   BODY is the sequence of statements inside a loop that will executed in
   sequence.  */

gimple 
gimple_build_omp_ordered (gimple_seq body)
{
  gimple p = gimple_alloc (GIMPLE_OMP_ORDERED, 0);
  if (body)
    gimple_omp_set_body (p, body);

  return p;
}


/* Build a GIMPLE_OMP_RETURN statement.
   WAIT_P is true if this is a non-waiting return.  */

gimple 
gimple_build_omp_return (bool wait_p)
{
  gimple p = gimple_alloc (GIMPLE_OMP_RETURN, 0);
  if (wait_p)
    gimple_omp_return_set_nowait (p);

  return p;
}


/* Build a GIMPLE_OMP_SECTIONS statement.

   BODY is a sequence of section statements.
   CLAUSES are any of the OMP sections contsruct's clauses: private,
   firstprivate, lastprivate, reduction, and nowait.  */

gimple 
gimple_build_omp_sections (gimple_seq body, tree clauses)
{
  gimple p = gimple_alloc (GIMPLE_OMP_SECTIONS, 0);
  if (body)
    gimple_omp_set_body (p, body);
  gimple_omp_sections_set_clauses (p, clauses);

  return p;
}


/* Build a GIMPLE_OMP_SECTIONS_SWITCH.  */

gimple
gimple_build_omp_sections_switch (void)
{
  return gimple_alloc (GIMPLE_OMP_SECTIONS_SWITCH, 0);
}


/* Build a GIMPLE_OMP_SINGLE statement.

   BODY is the sequence of statements that will be executed once.
   CLAUSES are any of the OMP single construct's clauses: private, firstprivate,
   copyprivate, nowait.  */

gimple 
gimple_build_omp_single (gimple_seq body, tree clauses)
{
  gimple p = gimple_alloc (GIMPLE_OMP_SINGLE, 0);
  if (body)
    gimple_omp_set_body (p, body);
  gimple_omp_single_set_clauses (p, clauses);

  return p;
}


/* Build a GIMPLE_CHANGE_DYNAMIC_TYPE statement.  TYPE is the new type
   for the location PTR.  */

gimple
gimple_build_cdt (tree type, tree ptr)
{
  gimple p = gimple_build_with_ops (GIMPLE_CHANGE_DYNAMIC_TYPE, 0, 2);
  gimple_cdt_set_new_type (p, type);
  gimple_cdt_set_location (p, ptr);

  return p;
}


/* Build a GIMPLE_OMP_ATOMIC_LOAD statement.  */

gimple
gimple_build_omp_atomic_load (tree lhs, tree rhs)
{
  gimple p = gimple_alloc (GIMPLE_OMP_ATOMIC_LOAD, 0);
  gimple_omp_atomic_load_set_lhs (p, lhs);
  gimple_omp_atomic_load_set_rhs (p, rhs);
  return p;
}

/* Build a GIMPLE_OMP_ATOMIC_STORE statement.

   VAL is the value we are storing.  */

gimple
gimple_build_omp_atomic_store (tree val)
{
  gimple p = gimple_alloc (GIMPLE_OMP_ATOMIC_STORE, 0);
  gimple_omp_atomic_store_set_val (p, val);
  return p;
}

/* Build a GIMPLE_PREDICT statement.  PREDICT is one of the predictors from
   predict.def, OUTCOME is NOT_TAKEN or TAKEN.  */

gimple
gimple_build_predict (enum br_predictor predictor, enum prediction outcome)
{
  gimple p = gimple_alloc (GIMPLE_PREDICT, 0);
  /* Ensure all the predictors fit into the lower bits of the subcode.  */
  gcc_assert ((int) END_PREDICTORS <= GF_PREDICT_TAKEN);
  gimple_predict_set_predictor (p, predictor);
  gimple_predict_set_outcome (p, outcome);
  return p;
}

/* Return which gimple structure is used by T.  The enums here are defined
   in gsstruct.def.  */

enum gimple_statement_structure_enum
gimple_statement_structure (gimple gs)
{
  return gss_for_code (gimple_code (gs));
}

#if defined ENABLE_GIMPLE_CHECKING
/* Complain of a gimple type mismatch and die.  */

void
gimple_check_failed (const_gimple gs, const char *file, int line,
                     const char *function, enum gimple_code code,
                     enum tree_code subcode)
{
  internal_error ("gimple check: expected %s(%s), have %s(%s) in %s, at %s:%d",
                  gimple_code_name[code],
                  tree_code_name[subcode],
                  gimple_code_name[gimple_code (gs)],
                  gs->gsbase.subcode > 0
                    ? tree_code_name[gs->gsbase.subcode]
                    : "",
                  function, trim_filename (file), line);
}
#endif /* ENABLE_GIMPLE_CHECKING */


/* Allocate a new GIMPLE sequence in GC memory and return it.  If
   there are free sequences in GIMPLE_SEQ_CACHE return one of those
   instead.  */

gimple_seq
gimple_seq_alloc (void)
{
  gimple_seq seq = gimple_seq_cache;
  if (seq)
    {
      gimple_seq_cache = gimple_seq_cache->next_free;
      gcc_assert (gimple_seq_cache != seq);
      memset (seq, 0, sizeof (*seq));
    }
  else
    {
      seq = (gimple_seq) ggc_alloc_cleared (sizeof (*seq));
#ifdef GATHER_STATISTICS
      gimple_alloc_counts[(int) gimple_alloc_kind_seq]++;
      gimple_alloc_sizes[(int) gimple_alloc_kind_seq] += sizeof (*seq);
#endif
    }

  return seq;
}

/* Return SEQ to the free pool of GIMPLE sequences.  */

void
gimple_seq_free (gimple_seq seq)
{
  if (seq == NULL)
    return;

  gcc_assert (gimple_seq_first (seq) == NULL);
  gcc_assert (gimple_seq_last (seq) == NULL);

  /* If this triggers, it's a sign that the same list is being freed
     twice.  */
  gcc_assert (seq != gimple_seq_cache || gimple_seq_cache == NULL);
  
  /* Add SEQ to the pool of free sequences.  */
  seq->next_free = gimple_seq_cache;
  gimple_seq_cache = seq;
}


/* Link gimple statement GS to the end of the sequence *SEQ_P.  If
   *SEQ_P is NULL, a new sequence is allocated.  */

void
gimple_seq_add_stmt (gimple_seq *seq_p, gimple gs)
{
  gimple_stmt_iterator si;

  if (gs == NULL)
    return;

  if (*seq_p == NULL)
    *seq_p = gimple_seq_alloc ();

  si = gsi_last (*seq_p);
  gsi_insert_after (&si, gs, GSI_NEW_STMT);
}


/* Append sequence SRC to the end of sequence *DST_P.  If *DST_P is
   NULL, a new sequence is allocated.  */

void
gimple_seq_add_seq (gimple_seq *dst_p, gimple_seq src)
{
  gimple_stmt_iterator si;

  if (src == NULL)
    return;

  if (*dst_p == NULL)
    *dst_p = gimple_seq_alloc ();

  si = gsi_last (*dst_p);
  gsi_insert_seq_after (&si, src, GSI_NEW_STMT);
}


/* Helper function of empty_body_p.  Return true if STMT is an empty
   statement.  */

static bool
empty_stmt_p (gimple stmt)
{
  if (gimple_code (stmt) == GIMPLE_NOP)
    return true;
  if (gimple_code (stmt) == GIMPLE_BIND)
    return empty_body_p (gimple_bind_body (stmt));
  return false;
}


/* Return true if BODY contains nothing but empty statements.  */

bool
empty_body_p (gimple_seq body)
{
  gimple_stmt_iterator i;


  if (gimple_seq_empty_p (body))
    return true;
  for (i = gsi_start (body); !gsi_end_p (i); gsi_next (&i))
    if (!empty_stmt_p (gsi_stmt (i)))
      return false;

  return true;
}


/* Perform a deep copy of sequence SRC and return the result.  */

gimple_seq
gimple_seq_copy (gimple_seq src)
{
  gimple_stmt_iterator gsi;
  gimple_seq new_seq = gimple_seq_alloc ();
  gimple stmt;

  for (gsi = gsi_start (src); !gsi_end_p (gsi); gsi_next (&gsi))
    {
      stmt = gimple_copy (gsi_stmt (gsi));
      gimple_seq_add_stmt (&new_seq, stmt);
    }

  return new_seq;
}


/* Walk all the statements in the sequence SEQ calling walk_gimple_stmt
   on each one.  WI is as in walk_gimple_stmt.
   
   If walk_gimple_stmt returns non-NULL, the walk is stopped, the
   value is stored in WI->CALLBACK_RESULT and the statement that
   produced the value is returned.

   Otherwise, all the statements are walked and NULL returned.  */

gimple
walk_gimple_seq (gimple_seq seq, walk_stmt_fn callback_stmt,
                 walk_tree_fn callback_op, struct walk_stmt_info *wi)
{
  gimple_stmt_iterator gsi;

  for (gsi = gsi_start (seq); !gsi_end_p (gsi); gsi_next (&gsi))
    {
      tree ret = walk_gimple_stmt (&gsi, callback_stmt, callback_op, wi);
      if (ret)
        {
          /* If CALLBACK_STMT or CALLBACK_OP return a value, WI must exist
             to hold it.  */
          gcc_assert (wi);
          wi->callback_result = ret;
          return gsi_stmt (gsi);
        }
    }

  if (wi)
    wi->callback_result = NULL_TREE;

  return NULL;
}


/* Helper function for walk_gimple_stmt.  Walk operands of a GIMPLE_ASM.  */

static tree
walk_gimple_asm (gimple stmt, walk_tree_fn callback_op,
                 struct walk_stmt_info *wi)
{
  tree ret;
  unsigned noutputs;
  const char **oconstraints;
  unsigned i;
  const char *constraint;
  bool allows_mem, allows_reg, is_inout;

  noutputs = gimple_asm_noutputs (stmt);
  oconstraints = (const char **) alloca ((noutputs) * sizeof (const char *));

  if (wi)
    wi->is_lhs = true;

  for (i = 0; i < noutputs; i++)
    {
      tree op = gimple_asm_output_op (stmt, i);
      constraint = TREE_STRING_POINTER (TREE_VALUE (TREE_PURPOSE (op)));
      oconstraints[i] = constraint;
      parse_output_constraint (&constraint, i, 0, 0, &allows_mem, &allows_reg,
                               &is_inout);
      if (wi)
        wi->val_only = (allows_reg || !allows_mem);
      ret = walk_tree (&TREE_VALUE (op), callback_op, wi, NULL);
      if (ret)
        return ret;
    }

  for (i = 0; i < gimple_asm_ninputs (stmt); i++)
    {
      tree op = gimple_asm_input_op (stmt, i);
      constraint = TREE_STRING_POINTER (TREE_VALUE (TREE_PURPOSE (op)));
      parse_input_constraint (&constraint, 0, 0, noutputs, 0,
                              oconstraints, &allows_mem, &allows_reg);
      if (wi)
        wi->val_only = (allows_reg || !allows_mem);

      /* Although input "m" is not really a LHS, we need a lvalue.  */
      if (wi)
        wi->is_lhs = !wi->val_only;
      ret = walk_tree (&TREE_VALUE (op), callback_op, wi, NULL);
      if (ret)
        return ret;
    }

  if (wi)
    {
      wi->is_lhs = false;
      wi->val_only = true;
    }

  return NULL_TREE;
}


/* Helper function of WALK_GIMPLE_STMT.  Walk every tree operand in
   STMT.  CALLBACK_OP and WI are as in WALK_GIMPLE_STMT.

   CALLBACK_OP is called on each operand of STMT via walk_tree.
   Additional parameters to walk_tree must be stored in WI.  For each operand
   OP, walk_tree is called as:

        walk_tree (&OP, CALLBACK_OP, WI, WI->PSET)

   If CALLBACK_OP returns non-NULL for an operand, the remaining
   operands are not scanned.

   The return value is that returned by the last call to walk_tree, or
   NULL_TREE if no CALLBACK_OP is specified.  */

inline tree
walk_gimple_op (gimple stmt, walk_tree_fn callback_op,
                struct walk_stmt_info *wi)
{
  struct pointer_set_t *pset = (wi) ? wi->pset : NULL;
  unsigned i;
  tree ret = NULL_TREE;

  switch (gimple_code (stmt))
    {
    case GIMPLE_ASSIGN:
      /* Walk the RHS operands.  A formal temporary LHS may use a
         COMPONENT_REF RHS.  */
      if (wi)
        wi->val_only = !is_gimple_formal_tmp_var (gimple_assign_lhs (stmt));

      for (i = 1; i < gimple_num_ops (stmt); i++)
        {
          ret = walk_tree (gimple_op_ptr (stmt, i), callback_op, wi,
                           pset);
          if (ret)
            return ret;
        }

      /* Walk the LHS.  If the RHS is appropriate for a memory, we
         may use a COMPONENT_REF on the LHS.  */
      if (wi)
        {
          /* If the RHS has more than 1 operand, it is not appropriate
             for the memory.  */
          wi->val_only = !is_gimple_mem_rhs (gimple_assign_rhs1 (stmt))
                         || !gimple_assign_single_p (stmt);
          wi->is_lhs = true;
        }

      ret = walk_tree (gimple_op_ptr (stmt, 0), callback_op, wi, pset);
      if (ret)
        return ret;

      if (wi)
        {
          wi->val_only = true;
          wi->is_lhs = false;
        }
      break;

    case GIMPLE_CALL:
      if (wi)
        wi->is_lhs = false;

      ret = walk_tree (gimple_call_chain_ptr (stmt), callback_op, wi, pset);
      if (ret)
        return ret;

      ret = walk_tree (gimple_call_fn_ptr (stmt), callback_op, wi, pset);
      if (ret)
        return ret;

      for (i = 0; i < gimple_call_num_args (stmt); i++)
        {
          ret = walk_tree (gimple_call_arg_ptr (stmt, i), callback_op, wi,
                           pset);
          if (ret)
            return ret;
        }

      if (wi)
        wi->is_lhs = true;

      ret = walk_tree (gimple_call_lhs_ptr (stmt), callback_op, wi, pset);
      if (ret)
        return ret;

      if (wi)
        wi->is_lhs = false;
      break;

    case GIMPLE_CATCH:
      ret = walk_tree (gimple_catch_types_ptr (stmt), callback_op, wi,
                       pset);
      if (ret)
        return ret;
      break;

    case GIMPLE_EH_FILTER:
      ret = walk_tree (gimple_eh_filter_types_ptr (stmt), callback_op, wi,
                       pset);
      if (ret)
        return ret;
      break;

    case GIMPLE_CHANGE_DYNAMIC_TYPE:
      ret = walk_tree (gimple_cdt_location_ptr (stmt), callback_op, wi, pset);
      if (ret)
        return ret;

      ret = walk_tree (gimple_cdt_new_type_ptr (stmt), callback_op, wi, pset);
      if (ret)
        return ret;
      break;

    case GIMPLE_ASM:
      ret = walk_gimple_asm (stmt, callback_op, wi);
      if (ret)
        return ret;
      break;

    case GIMPLE_OMP_CONTINUE:
      ret = walk_tree (gimple_omp_continue_control_def_ptr (stmt),
                       callback_op, wi, pset);
      if (ret)
        return ret;

      ret = walk_tree (gimple_omp_continue_control_use_ptr (stmt),
                       callback_op, wi, pset);
      if (ret)
        return ret;
      break;

    case GIMPLE_OMP_CRITICAL:
      ret = walk_tree (gimple_omp_critical_name_ptr (stmt), callback_op, wi,
                       pset);
      if (ret)
        return ret;
      break;

    case GIMPLE_OMP_FOR:
      ret = walk_tree (gimple_omp_for_clauses_ptr (stmt), callback_op, wi,
                       pset);
      if (ret)
        return ret;
      for (i = 0; i < gimple_omp_for_collapse (stmt); i++)
        {
          ret = walk_tree (gimple_omp_for_index_ptr (stmt, i), callback_op,
                           wi, pset);
          if (ret)
            return ret;
          ret = walk_tree (gimple_omp_for_initial_ptr (stmt, i), callback_op,
                           wi, pset);
          if (ret)
            return ret;
          ret = walk_tree (gimple_omp_for_final_ptr (stmt, i), callback_op,
                           wi, pset);
          if (ret)
            return ret;
          ret = walk_tree (gimple_omp_for_incr_ptr (stmt, i), callback_op,
                           wi, pset);
        }
      if (ret)
        return ret;
      break;

    case GIMPLE_OMP_PARALLEL:
      ret = walk_tree (gimple_omp_parallel_clauses_ptr (stmt), callback_op,
                       wi, pset);
      if (ret)
        return ret;
      ret = walk_tree (gimple_omp_parallel_child_fn_ptr (stmt), callback_op,
                       wi, pset);
      if (ret)
        return ret;
      ret = walk_tree (gimple_omp_parallel_data_arg_ptr (stmt), callback_op,
                       wi, pset);
      if (ret)
        return ret;
      break;

    case GIMPLE_OMP_TASK:
      ret = walk_tree (gimple_omp_task_clauses_ptr (stmt), callback_op,
                       wi, pset);
      if (ret)
        return ret;
      ret = walk_tree (gimple_omp_task_child_fn_ptr (stmt), callback_op,
                       wi, pset);
      if (ret)
        return ret;
      ret = walk_tree (gimple_omp_task_data_arg_ptr (stmt), callback_op,
                       wi, pset);
      if (ret)
        return ret;
      ret = walk_tree (gimple_omp_task_copy_fn_ptr (stmt), callback_op,
                       wi, pset);
      if (ret)
        return ret;
      ret = walk_tree (gimple_omp_task_arg_size_ptr (stmt), callback_op,
                       wi, pset);
      if (ret)
        return ret;
      ret = walk_tree (gimple_omp_task_arg_align_ptr (stmt), callback_op,
                       wi, pset);
      if (ret)
        return ret;
      break;

    case GIMPLE_OMP_SECTIONS:
      ret = walk_tree (gimple_omp_sections_clauses_ptr (stmt), callback_op,
                       wi, pset);
      if (ret)
        return ret;

      ret = walk_tree (gimple_omp_sections_control_ptr (stmt), callback_op,
                       wi, pset);
      if (ret)
        return ret;

      break;

    case GIMPLE_OMP_SINGLE:
      ret = walk_tree (gimple_omp_single_clauses_ptr (stmt), callback_op, wi,
                       pset);
      if (ret)
        return ret;
      break;

    case GIMPLE_OMP_ATOMIC_LOAD:
      ret = walk_tree (gimple_omp_atomic_load_lhs_ptr (stmt), callback_op, wi,
                       pset);
      if (ret)
        return ret;

      ret = walk_tree (gimple_omp_atomic_load_rhs_ptr (stmt), callback_op, wi,
                       pset);
      if (ret)
        return ret;
      break;

    case GIMPLE_OMP_ATOMIC_STORE:
      ret = walk_tree (gimple_omp_atomic_store_val_ptr (stmt), callback_op,
                       wi, pset);
      if (ret)
        return ret;
      break;

      /* Tuples that do not have operands.  */
    case GIMPLE_NOP:
    case GIMPLE_RESX:
    case GIMPLE_OMP_RETURN:
    case GIMPLE_PREDICT:
      break;

    default:
      {
        enum gimple_statement_structure_enum gss;
        gss = gimple_statement_structure (stmt);
        if (gss == GSS_WITH_OPS || gss == GSS_WITH_MEM_OPS)
          for (i = 0; i < gimple_num_ops (stmt); i++)
            {
              ret = walk_tree (gimple_op_ptr (stmt, i), callback_op, wi, pset);
              if (ret)
                return ret;
            }
      }
      break;
    }

  return NULL_TREE;
}


/* Walk the current statement in GSI (optionally using traversal state
   stored in WI).  If WI is NULL, no state is kept during traversal.
   The callback CALLBACK_STMT is called.  If CALLBACK_STMT indicates
   that it has handled all the operands of the statement, its return
   value is returned.  Otherwise, the return value from CALLBACK_STMT
   is discarded and its operands are scanned.

   If CALLBACK_STMT is NULL or it didn't handle the operands,
   CALLBACK_OP is called on each operand of the statement via
   walk_gimple_op.  If walk_gimple_op returns non-NULL for any
   operand, the remaining operands are not scanned.  In this case, the
   return value from CALLBACK_OP is returned.

   In any other case, NULL_TREE is returned.  */

tree
walk_gimple_stmt (gimple_stmt_iterator *gsi, walk_stmt_fn callback_stmt,
                  walk_tree_fn callback_op, struct walk_stmt_info *wi)
{
  gimple ret;
  tree tree_ret;
  gimple stmt = gsi_stmt (*gsi);

  if (wi)
    wi->gsi = *gsi;

  if (wi && wi->want_locations && gimple_has_location (stmt))
    input_location = gimple_location (stmt);

  ret = NULL;

  /* Invoke the statement callback.  Return if the callback handled
     all of STMT operands by itself.  */
  if (callback_stmt)
    {
      bool handled_ops = false;
      tree_ret = callback_stmt (gsi, &handled_ops, wi);
      if (handled_ops)
        return tree_ret;

      /* If CALLBACK_STMT did not handle operands, it should not have
         a value to return.  */
      gcc_assert (tree_ret == NULL);

      /* Re-read stmt in case the callback changed it.  */
      stmt = gsi_stmt (*gsi);
    }

  /* If CALLBACK_OP is defined, invoke it on every operand of STMT.  */
  if (callback_op)
    {
      tree_ret = walk_gimple_op (stmt, callback_op, wi);
      if (tree_ret)
        return tree_ret;
    }

  /* If STMT can have statements inside (e.g. GIMPLE_BIND), walk them.  */
  switch (gimple_code (stmt))
    {
    case GIMPLE_BIND:
      ret = walk_gimple_seq (gimple_bind_body (stmt), callback_stmt,
                             callback_op, wi);
      if (ret)
        return wi->callback_result;
      break;

    case GIMPLE_CATCH:
      ret = walk_gimple_seq (gimple_catch_handler (stmt), callback_stmt,
                             callback_op, wi);
      if (ret)
        return wi->callback_result;
      break;

    case GIMPLE_EH_FILTER:
      ret = walk_gimple_seq (gimple_eh_filter_failure (stmt), callback_stmt,
                             callback_op, wi);
      if (ret)
        return wi->callback_result;
      break;

    case GIMPLE_TRY:
      ret = walk_gimple_seq (gimple_try_eval (stmt), callback_stmt, callback_op,
                             wi);
      if (ret)
        return wi->callback_result;

      ret = walk_gimple_seq (gimple_try_cleanup (stmt), callback_stmt,
                             callback_op, wi);
      if (ret)
        return wi->callback_result;
      break;

    case GIMPLE_OMP_FOR:
      ret = walk_gimple_seq (gimple_omp_for_pre_body (stmt), callback_stmt,
                             callback_op, wi);
      if (ret)
        return wi->callback_result;

      /* FALL THROUGH.  */
    case GIMPLE_OMP_CRITICAL:
    case GIMPLE_OMP_MASTER:
    case GIMPLE_OMP_ORDERED:
    case GIMPLE_OMP_SECTION:
    case GIMPLE_OMP_PARALLEL:
    case GIMPLE_OMP_TASK:
    case GIMPLE_OMP_SECTIONS:
    case GIMPLE_OMP_SINGLE:
      ret = walk_gimple_seq (gimple_omp_body (stmt), callback_stmt, callback_op,
                             wi);
      if (ret)
        return wi->callback_result;
      break;

    case GIMPLE_WITH_CLEANUP_EXPR:
      ret = walk_gimple_seq (gimple_wce_cleanup (stmt), callback_stmt,
                             callback_op, wi);
      if (ret)
        return wi->callback_result;
      break;

    default:
      gcc_assert (!gimple_has_substatements (stmt));
      break;
    }

  return NULL;
}


/* Set sequence SEQ to be the GIMPLE body for function FN.  */

void
gimple_set_body (tree fndecl, gimple_seq seq)
{
  struct function *fn = DECL_STRUCT_FUNCTION (fndecl);
  if (fn == NULL)
    {
      /* If FNDECL still does not have a function structure associated
         with it, then it does not make sense for it to receive a
         GIMPLE body.  */
      gcc_assert (seq == NULL);
    }
  else
    fn->gimple_body = seq;
}


/* Return the body of GIMPLE statements for function FN.  */

gimple_seq
gimple_body (tree fndecl)
{
  struct function *fn = DECL_STRUCT_FUNCTION (fndecl);
  return fn ? fn->gimple_body : NULL;
}

/* Return true when FNDECL has Gimple body either in unlowered
   or CFG form.  */
bool
gimple_has_body_p (tree fndecl)
{
  struct function *fn = DECL_STRUCT_FUNCTION (fndecl);
  return (gimple_body (fndecl) || (fn && fn->cfg));
}

/* Detect flags from a GIMPLE_CALL.  This is just like
   call_expr_flags, but for gimple tuples.  */

int
gimple_call_flags (const_gimple stmt)
{
  int flags;
  tree decl = gimple_call_fndecl (stmt);
  tree t;

  if (decl)
    flags = flags_from_decl_or_type (decl);
  else
    {
      t = TREE_TYPE (gimple_call_fn (stmt));
      if (t && TREE_CODE (t) == POINTER_TYPE)
        flags = flags_from_decl_or_type (TREE_TYPE (t));
      else
        flags = 0;
    }

  return flags;
}


/* Return true if GS is a copy assignment.  */

bool
gimple_assign_copy_p (gimple gs)
{
  return gimple_code (gs) == GIMPLE_ASSIGN
         && get_gimple_rhs_class (gimple_assign_rhs_code (gs))
            == GIMPLE_SINGLE_RHS
         && is_gimple_val (gimple_op (gs, 1));
}


/* Return true if GS is a SSA_NAME copy assignment.  */

bool
gimple_assign_ssa_name_copy_p (gimple gs)
{
  return (gimple_code (gs) == GIMPLE_ASSIGN
          && (get_gimple_rhs_class (gimple_assign_rhs_code (gs))
              == GIMPLE_SINGLE_RHS)
          && TREE_CODE (gimple_assign_lhs (gs)) == SSA_NAME
          && TREE_CODE (gimple_assign_rhs1 (gs)) == SSA_NAME);
}


/* Return true if GS is an assignment with a singleton RHS, i.e.,
   there is no operator associated with the assignment itself.
   Unlike gimple_assign_copy_p, this predicate returns true for
   any RHS operand, including those that perform an operation
   and do not have the semantics of a copy, such as COND_EXPR.  */

bool
gimple_assign_single_p (gimple gs)
{
  return (gimple_code (gs) == GIMPLE_ASSIGN
          && get_gimple_rhs_class (gimple_assign_rhs_code (gs))
             == GIMPLE_SINGLE_RHS);
}

/* Return true if GS is an assignment with a unary RHS, but the
   operator has no effect on the assigned value.  The logic is adapted
   from STRIP_NOPS.  This predicate is intended to be used in tuplifying
   instances in which STRIP_NOPS was previously applied to the RHS of
   an assignment.

   NOTE: In the use cases that led to the creation of this function
   and of gimple_assign_single_p, it is typical to test for either
   condition and to proceed in the same manner.  In each case, the
   assigned value is represented by the single RHS operand of the
   assignment.  I suspect there may be cases where gimple_assign_copy_p,
   gimple_assign_single_p, or equivalent logic is used where a similar
   treatment of unary NOPs is appropriate.  */
   
bool
gimple_assign_unary_nop_p (gimple gs)
{
  return (gimple_code (gs) == GIMPLE_ASSIGN
          && (CONVERT_EXPR_CODE_P (gimple_assign_rhs_code (gs))
              || gimple_assign_rhs_code (gs) == NON_LVALUE_EXPR)
          && gimple_assign_rhs1 (gs) != error_mark_node
          && (TYPE_MODE (TREE_TYPE (gimple_assign_lhs (gs)))
              == TYPE_MODE (TREE_TYPE (gimple_assign_rhs1 (gs)))));
}

/* Set BB to be the basic block holding G.  */

void
gimple_set_bb (gimple stmt, basic_block bb)
{
  stmt->gsbase.bb = bb;

  /* If the statement is a label, add the label to block-to-labels map
     so that we can speed up edge creation for GIMPLE_GOTOs.  */
  if (cfun->cfg && gimple_code (stmt) == GIMPLE_LABEL)
    {
      tree t;
      int uid;

      t = gimple_label_label (stmt);
      uid = LABEL_DECL_UID (t);
      if (uid == -1)
        {
          unsigned old_len = VEC_length (basic_block, label_to_block_map);
          LABEL_DECL_UID (t) = uid = cfun->cfg->last_label_uid++;
          if (old_len <= (unsigned) uid)
            {
              unsigned new_len = 3 * uid / 2;

              VEC_safe_grow_cleared (basic_block, gc, label_to_block_map,
                                     new_len);
            }
        }

      VEC_replace (basic_block, label_to_block_map, uid, bb);
    }
}


/* Fold the expression computed by STMT.  If the expression can be
   folded, return the folded result, otherwise return NULL.  STMT is
   not modified.  */

tree
gimple_fold (const_gimple stmt)
{
  switch (gimple_code (stmt))
    {
    case GIMPLE_COND:
      return fold_binary (gimple_cond_code (stmt),
                          boolean_type_node,
                          gimple_cond_lhs (stmt),
                          gimple_cond_rhs (stmt));

    case GIMPLE_ASSIGN:
      switch (get_gimple_rhs_class (gimple_assign_rhs_code (stmt)))
        {
        case GIMPLE_UNARY_RHS:
          return fold_unary (gimple_assign_rhs_code (stmt),
                             TREE_TYPE (gimple_assign_lhs (stmt)),
                             gimple_assign_rhs1 (stmt));
        case GIMPLE_BINARY_RHS:
          return fold_binary (gimple_assign_rhs_code (stmt),
                              TREE_TYPE (gimple_assign_lhs (stmt)),
                              gimple_assign_rhs1 (stmt),
                              gimple_assign_rhs2 (stmt));
        case GIMPLE_SINGLE_RHS:
          return fold (gimple_assign_rhs1 (stmt));
        default:;
        }
      break;

    case GIMPLE_SWITCH:
      return gimple_switch_index (stmt);

    case GIMPLE_CALL:
      return NULL_TREE;

    default:
      break;
    }

  gcc_unreachable ();
}


/* Modify the RHS of the assignment pointed-to by GSI using the
   operands in the expression tree EXPR.

   NOTE: The statement pointed-to by GSI may be reallocated if it
   did not have enough operand slots.

   This function is useful to convert an existing tree expression into
   the flat representation used for the RHS of a GIMPLE assignment.
   It will reallocate memory as needed to expand or shrink the number
   of operand slots needed to represent EXPR.

   NOTE: If you find yourself building a tree and then calling this
   function, you are most certainly doing it the slow way.  It is much
   better to build a new assignment or to use the function
   gimple_assign_set_rhs_with_ops, which does not require an
   expression tree to be built.  */

void
gimple_assign_set_rhs_from_tree (gimple_stmt_iterator *gsi, tree expr)
{
  enum tree_code subcode;
  tree op1, op2;

  extract_ops_from_tree (expr, &subcode, &op1, &op2);
  gimple_assign_set_rhs_with_ops (gsi, subcode, op1, op2);
}


/* Set the RHS of assignment statement pointed-to by GSI to CODE with
   operands OP1 and OP2.

   NOTE: The statement pointed-to by GSI may be reallocated if it
   did not have enough operand slots.  */

void
gimple_assign_set_rhs_with_ops (gimple_stmt_iterator *gsi, enum tree_code code,
                                tree op1, tree op2)
{
  unsigned new_rhs_ops = get_gimple_rhs_num_ops (code);
  gimple stmt = gsi_stmt (*gsi);

  /* If the new CODE needs more operands, allocate a new statement.  */
  if (gimple_num_ops (stmt) < new_rhs_ops + 1)
    {
      tree lhs = gimple_assign_lhs (stmt);
      gimple new_stmt = gimple_alloc (gimple_code (stmt), new_rhs_ops + 1);
      memcpy (new_stmt, stmt, gimple_size (gimple_code (stmt)));
      gsi_replace (gsi, new_stmt, true);
      stmt = new_stmt;

      /* The LHS needs to be reset as this also changes the SSA name
         on the LHS.  */
      gimple_assign_set_lhs (stmt, lhs);
    }

  gimple_set_num_ops (stmt, new_rhs_ops + 1);
  gimple_set_subcode (stmt, code);
  gimple_assign_set_rhs1 (stmt, op1);
  if (new_rhs_ops > 1)
    gimple_assign_set_rhs2 (stmt, op2);
}


/* Return the LHS of a statement that performs an assignment,
   either a GIMPLE_ASSIGN or a GIMPLE_CALL.  Returns NULL_TREE
   for a call to a function that returns no value, or for a
   statement other than an assignment or a call.  */

tree
gimple_get_lhs (const_gimple stmt)
{
  enum gimple_code code = gimple_code (stmt);

  if (code == GIMPLE_ASSIGN)
    return gimple_assign_lhs (stmt);
  else if (code == GIMPLE_CALL)
    return gimple_call_lhs (stmt);
  else
    return NULL_TREE;
}


/* Set the LHS of a statement that performs an assignment,
   either a GIMPLE_ASSIGN or a GIMPLE_CALL.  */

void
gimple_set_lhs (gimple stmt, tree lhs)
{
  enum gimple_code code = gimple_code (stmt);

  if (code == GIMPLE_ASSIGN)
    gimple_assign_set_lhs (stmt, lhs);
  else if (code == GIMPLE_CALL)
    gimple_call_set_lhs (stmt, lhs);
  else
    gcc_unreachable();
}


/* Return a deep copy of statement STMT.  All the operands from STMT
   are reallocated and copied using unshare_expr.  The DEF, USE, VDEF
   and VUSE operand arrays are set to empty in the new copy.  */

gimple
gimple_copy (gimple stmt)
{
  enum gimple_code code = gimple_code (stmt);
  unsigned num_ops = gimple_num_ops (stmt);
  gimple copy = gimple_alloc (code, num_ops);
  unsigned i;

  /* Shallow copy all the fields from STMT.  */
  memcpy (copy, stmt, gimple_size (code));

  /* If STMT has sub-statements, deep-copy them as well.  */
  if (gimple_has_substatements (stmt))
    {
      gimple_seq new_seq;
      tree t;

      switch (gimple_code (stmt))
        {
        case GIMPLE_BIND:
          new_seq = gimple_seq_copy (gimple_bind_body (stmt));
          gimple_bind_set_body (copy, new_seq);
          gimple_bind_set_vars (copy, unshare_expr (gimple_bind_vars (stmt)));
          gimple_bind_set_block (copy, gimple_bind_block (stmt));
          break;

        case GIMPLE_CATCH:
          new_seq = gimple_seq_copy (gimple_catch_handler (stmt));
          gimple_catch_set_handler (copy, new_seq);
          t = unshare_expr (gimple_catch_types (stmt));
          gimple_catch_set_types (copy, t);
          break;

        case GIMPLE_EH_FILTER:
          new_seq = gimple_seq_copy (gimple_eh_filter_failure (stmt));
          gimple_eh_filter_set_failure (copy, new_seq);
          t = unshare_expr (gimple_eh_filter_types (stmt));
          gimple_eh_filter_set_types (copy, t);
          break;

        case GIMPLE_TRY:
          new_seq = gimple_seq_copy (gimple_try_eval (stmt));
          gimple_try_set_eval (copy, new_seq);
          new_seq = gimple_seq_copy (gimple_try_cleanup (stmt));
          gimple_try_set_cleanup (copy, new_seq);
          break;

        case GIMPLE_OMP_FOR:
          new_seq = gimple_seq_copy (gimple_omp_for_pre_body (stmt));
          gimple_omp_for_set_pre_body (copy, new_seq);
          t = unshare_expr (gimple_omp_for_clauses (stmt));
          gimple_omp_for_set_clauses (copy, t);
          copy->gimple_omp_for.iter
            = GGC_NEWVEC (struct gimple_omp_for_iter,
                          gimple_omp_for_collapse (stmt));
          for (i = 0; i < gimple_omp_for_collapse (stmt); i++)
            {
              gimple_omp_for_set_cond (copy, i,
                                       gimple_omp_for_cond (stmt, i));
              gimple_omp_for_set_index (copy, i,
                                        gimple_omp_for_index (stmt, i));
              t = unshare_expr (gimple_omp_for_initial (stmt, i));
              gimple_omp_for_set_initial (copy, i, t);
              t = unshare_expr (gimple_omp_for_final (stmt, i));
              gimple_omp_for_set_final (copy, i, t);
              t = unshare_expr (gimple_omp_for_incr (stmt, i));
              gimple_omp_for_set_incr (copy, i, t);
            }
          goto copy_omp_body;

        case GIMPLE_OMP_PARALLEL:
          t = unshare_expr (gimple_omp_parallel_clauses (stmt));
          gimple_omp_parallel_set_clauses (copy, t);
          t = unshare_expr (gimple_omp_parallel_child_fn (stmt));
          gimple_omp_parallel_set_child_fn (copy, t);
          t = unshare_expr (gimple_omp_parallel_data_arg (stmt));
          gimple_omp_parallel_set_data_arg (copy, t);
          goto copy_omp_body;

        case GIMPLE_OMP_TASK:
          t = unshare_expr (gimple_omp_task_clauses (stmt));
          gimple_omp_task_set_clauses (copy, t);
          t = unshare_expr (gimple_omp_task_child_fn (stmt));
          gimple_omp_task_set_child_fn (copy, t);
          t = unshare_expr (gimple_omp_task_data_arg (stmt));
          gimple_omp_task_set_data_arg (copy, t);
          t = unshare_expr (gimple_omp_task_copy_fn (stmt));
          gimple_omp_task_set_copy_fn (copy, t);
          t = unshare_expr (gimple_omp_task_arg_size (stmt));
          gimple_omp_task_set_arg_size (copy, t);
          t = unshare_expr (gimple_omp_task_arg_align (stmt));
          gimple_omp_task_set_arg_align (copy, t);
          goto copy_omp_body;

        case GIMPLE_OMP_CRITICAL:
          t = unshare_expr (gimple_omp_critical_name (stmt));
          gimple_omp_critical_set_name (copy, t);
          goto copy_omp_body;

        case GIMPLE_OMP_SECTIONS:
          t = unshare_expr (gimple_omp_sections_clauses (stmt));
          gimple_omp_sections_set_clauses (copy, t);
          t = unshare_expr (gimple_omp_sections_control (stmt));
          gimple_omp_sections_set_control (copy, t);
          /* FALLTHRU  */

        case GIMPLE_OMP_SINGLE:
        case GIMPLE_OMP_SECTION:
        case GIMPLE_OMP_MASTER:
        case GIMPLE_OMP_ORDERED:
        copy_omp_body:
          new_seq = gimple_seq_copy (gimple_omp_body (stmt));
          gimple_omp_set_body (copy, new_seq);
          break;

        case GIMPLE_WITH_CLEANUP_EXPR:
          new_seq = gimple_seq_copy (gimple_wce_cleanup (stmt));
          gimple_wce_set_cleanup (copy, new_seq);
          break;

        default:
          gcc_unreachable ();
        }
    }

  /* Make copy of operands.  */
  if (num_ops > 0)
    {
      for (i = 0; i < num_ops; i++)
        gimple_set_op (copy, i, unshare_expr (gimple_op (stmt, i)));

      /* Clear out SSA operand vectors on COPY.  Note that we cannot
         call the API functions for setting addresses_taken, stores
         and loads.  These functions free the previous values, and we
         cannot do that on COPY as it will affect the original
         statement.  */
      if (gimple_has_ops (stmt))
        {
          gimple_set_def_ops (copy, NULL);
          gimple_set_use_ops (copy, NULL);
          copy->gsops.opbase.addresses_taken = NULL;
        }

      if (gimple_has_mem_ops (stmt))
        {
          gimple_set_vdef_ops (copy, NULL);
          gimple_set_vuse_ops (copy, NULL);
          copy->gsmem.membase.stores = NULL;
          copy->gsmem.membase.loads = NULL;
        }

      update_stmt (copy);
    }

  return copy;
}


/* Set the MODIFIED flag to MODIFIEDP, iff the gimple statement G has
   a MODIFIED field.  */

void
gimple_set_modified (gimple s, bool modifiedp)
{
  if (gimple_has_ops (s))
    {
      s->gsbase.modified = (unsigned) modifiedp;

      if (modifiedp
          && cfun->gimple_df
          && is_gimple_call (s)
          && gimple_call_noreturn_p (s))
        VEC_safe_push (gimple, gc, MODIFIED_NORETURN_CALLS (cfun), s);
    }
}


/* Return true if statement S has side-effects.  We consider a
   statement to have side effects if:

   - It is a GIMPLE_CALL not marked with ECF_PURE or ECF_CONST.
   - Any of its operands are marked TREE_THIS_VOLATILE or TREE_SIDE_EFFECTS.  */

bool
gimple_has_side_effects (const_gimple s)
{
  unsigned i;

  /* We don't have to scan the arguments to check for
     volatile arguments, though, at present, we still
     do a scan to check for TREE_SIDE_EFFECTS.  */
  if (gimple_has_volatile_ops (s))
    return true;

  if (is_gimple_call (s))
    {
      unsigned nargs = gimple_call_num_args (s);

      if (!(gimple_call_flags (s) & (ECF_CONST | ECF_PURE)))
        return true;
      else if (gimple_call_flags (s) & ECF_LOOPING_CONST_OR_PURE)
        /* An infinite loop is considered a side effect.  */
        return true;

      if (gimple_call_lhs (s)
          && TREE_SIDE_EFFECTS (gimple_call_lhs (s)))
        {
          gcc_assert (gimple_has_volatile_ops (s));
          return true;
        }

      if (TREE_SIDE_EFFECTS (gimple_call_fn (s)))
        return true;

      for (i = 0; i < nargs; i++)
        if (TREE_SIDE_EFFECTS (gimple_call_arg (s, i)))
          {
            gcc_assert (gimple_has_volatile_ops (s));
            return true;
          }

      return false;
    }
  else
    {
      for (i = 0; i < gimple_num_ops (s); i++)
        if (TREE_SIDE_EFFECTS (gimple_op (s, i)))
          {
            gcc_assert (gimple_has_volatile_ops (s));
            return true;
          }
    }

  return false;
}

/* Return true if the RHS of statement S has side effects.
   We may use it to determine if it is admissable to replace
   an assignment or call with a copy of a previously-computed
   value.  In such cases, side-effects due the the LHS are
   preserved.  */

bool
gimple_rhs_has_side_effects (const_gimple s)
{
  unsigned i;

  if (is_gimple_call (s))
    {
      unsigned nargs = gimple_call_num_args (s);

      if (!(gimple_call_flags (s) & (ECF_CONST | ECF_PURE)))
        return true;

      /* We cannot use gimple_has_volatile_ops here,
         because we must ignore a volatile LHS.  */
      if (TREE_SIDE_EFFECTS (gimple_call_fn (s))
          || TREE_THIS_VOLATILE (gimple_call_fn (s)))
        {
          gcc_assert (gimple_has_volatile_ops (s));
          return true;
        }

      for (i = 0; i < nargs; i++)
        if (TREE_SIDE_EFFECTS (gimple_call_arg (s, i))
            || TREE_THIS_VOLATILE (gimple_call_arg (s, i)))
          return true;

      return false;
    }
  else if (is_gimple_assign (s))
    {
      /* Skip the first operand, the LHS. */
      for (i = 1; i < gimple_num_ops (s); i++)
        if (TREE_SIDE_EFFECTS (gimple_op (s, i))
            || TREE_THIS_VOLATILE (gimple_op (s, i)))
          {
            gcc_assert (gimple_has_volatile_ops (s));
            return true;
          }
    }
  else
    {
      /* For statements without an LHS, examine all arguments.  */
      for (i = 0; i < gimple_num_ops (s); i++)
        if (TREE_SIDE_EFFECTS (gimple_op (s, i))
            || TREE_THIS_VOLATILE (gimple_op (s, i)))
          {
            gcc_assert (gimple_has_volatile_ops (s));
            return true;
          }
    }

  return false;
}


/* Helper for gimple_could_trap_p and gimple_assign_rhs_could_trap_p.
   Return true if S can trap.  If INCLUDE_LHS is true and S is a
   GIMPLE_ASSIGN, the LHS of the assignment is also checked.
   Otherwise, only the RHS of the assignment is checked.  */

static bool
gimple_could_trap_p_1 (gimple s, bool include_lhs)
{
  unsigned i, start;
  tree t, div = NULL_TREE;
  enum tree_code op;

  start = (is_gimple_assign (s) && !include_lhs) ? 1 : 0;

  for (i = start; i < gimple_num_ops (s); i++)
    if (tree_could_trap_p (gimple_op (s, i)))
      return true;

  switch (gimple_code (s))
    {
    case GIMPLE_ASM:
      return gimple_asm_volatile_p (s);

    case GIMPLE_CALL:
      t = gimple_call_fndecl (s);
      /* Assume that calls to weak functions may trap.  */
      if (!t || !DECL_P (t) || DECL_WEAK (t))
        return true;
      return false;

    case GIMPLE_ASSIGN:
      t = gimple_expr_type (s);
      op = gimple_assign_rhs_code (s);
      if (get_gimple_rhs_class (op) == GIMPLE_BINARY_RHS)
        div = gimple_assign_rhs2 (s);
      return (operation_could_trap_p (op, FLOAT_TYPE_P (t),
                                      (INTEGRAL_TYPE_P (t)
                                       && TYPE_OVERFLOW_TRAPS (t)),
                                      div));

    default:
      break;
    }

  return false;

}


/* Return true if statement S can trap.  */

bool
gimple_could_trap_p (gimple s)
{
  return gimple_could_trap_p_1 (s, true);
}


/* Return true if RHS of a GIMPLE_ASSIGN S can trap.  */

bool
gimple_assign_rhs_could_trap_p (gimple s)
{
  gcc_assert (is_gimple_assign (s));
  return gimple_could_trap_p_1 (s, false);
}


/* Print debugging information for gimple stmts generated.  */

void
dump_gimple_statistics (void)
{
#ifdef GATHER_STATISTICS
  int i, total_tuples = 0, total_bytes = 0;

  fprintf (stderr, "\nGIMPLE statements\n");
  fprintf (stderr, "Kind                   Stmts      Bytes\n");
  fprintf (stderr, "---------------------------------------\n");
  for (i = 0; i < (int) gimple_alloc_kind_all; ++i)
    {
      fprintf (stderr, "%-20s %7d %10d\n", gimple_alloc_kind_names[i],
          gimple_alloc_counts[i], gimple_alloc_sizes[i]);
      total_tuples += gimple_alloc_counts[i];
      total_bytes += gimple_alloc_sizes[i];
    }
  fprintf (stderr, "---------------------------------------\n");
  fprintf (stderr, "%-20s %7d %10d\n", "Total", total_tuples, total_bytes);
  fprintf (stderr, "---------------------------------------\n");
#else
  fprintf (stderr, "No gimple statistics\n");
#endif
}


/* Deep copy SYMS into the set of symbols stored by STMT.  If SYMS is
   NULL or empty, the storage used is freed up.  */

void
gimple_set_stored_syms (gimple stmt, bitmap syms, bitmap_obstack *obs)
{
  gcc_assert (gimple_has_mem_ops (stmt));

  if (syms == NULL || bitmap_empty_p (syms))
    BITMAP_FREE (stmt->gsmem.membase.stores);
  else
    {
      if (stmt->gsmem.membase.stores == NULL)
        stmt->gsmem.membase.stores = BITMAP_ALLOC (obs);

      bitmap_copy (stmt->gsmem.membase.stores, syms);
    }
}


/* Deep copy SYMS into the set of symbols loaded by STMT.  If SYMS is
   NULL or empty, the storage used is freed up.  */

void
gimple_set_loaded_syms (gimple stmt, bitmap syms, bitmap_obstack *obs)
{
  gcc_assert (gimple_has_mem_ops (stmt));

  if (syms == NULL || bitmap_empty_p (syms))
    BITMAP_FREE (stmt->gsmem.membase.loads);
  else
    {
      if (stmt->gsmem.membase.loads == NULL)
        stmt->gsmem.membase.loads = BITMAP_ALLOC (obs);

      bitmap_copy (stmt->gsmem.membase.loads, syms);
    }
}


/* Return the number of operands needed on the RHS of a GIMPLE
   assignment for an expression with tree code CODE.  */

unsigned
get_gimple_rhs_num_ops (enum tree_code code)
{
  enum gimple_rhs_class rhs_class = get_gimple_rhs_class (code);

  if (rhs_class == GIMPLE_UNARY_RHS || rhs_class == GIMPLE_SINGLE_RHS)
    return 1;
  else if (rhs_class == GIMPLE_BINARY_RHS)
    return 2;
  else
    gcc_unreachable ();
}

#define DEFTREECODE(SYM, STRING, TYPE, NARGS)                               \
  (unsigned char)                                                           \
  ((TYPE) == tcc_unary ? GIMPLE_UNARY_RHS                                   \
   : ((TYPE) == tcc_binary                                                  \
      || (TYPE) == tcc_comparison) ? GIMPLE_BINARY_RHS                      \
   : ((TYPE) == tcc_constant                                                \
      || (TYPE) == tcc_declaration                                          \
      || (TYPE) == tcc_reference) ? GIMPLE_SINGLE_RHS                       \
   : ((SYM) == TRUTH_AND_EXPR                                               \
      || (SYM) == TRUTH_OR_EXPR                                             \
      || (SYM) == TRUTH_XOR_EXPR) ? GIMPLE_BINARY_RHS                       \
   : (SYM) == TRUTH_NOT_EXPR ? GIMPLE_UNARY_RHS                             \
   : ((SYM) == COND_EXPR                                                    \
      || (SYM) == CONSTRUCTOR                                               \
      || (SYM) == OBJ_TYPE_REF                                              \
      || (SYM) == ASSERT_EXPR                                               \
      || (SYM) == ADDR_EXPR                                                 \
      || (SYM) == WITH_SIZE_EXPR                                            \
      || (SYM) == EXC_PTR_EXPR                                              \
      || (SYM) == SSA_NAME                                                  \
      || (SYM) == FILTER_EXPR                                               \
      || (SYM) == POLYNOMIAL_CHREC                                          \
      || (SYM) == DOT_PROD_EXPR                                             \
      || (SYM) == VEC_COND_EXPR                                             \
      || (SYM) == REALIGN_LOAD_EXPR) ? GIMPLE_SINGLE_RHS                    \
   : GIMPLE_INVALID_RHS),
#define END_OF_BASE_TREE_CODES (unsigned char) GIMPLE_INVALID_RHS,

const unsigned char gimple_rhs_class_table[] = {
#include "all-tree.def"
};

#undef DEFTREECODE
#undef END_OF_BASE_TREE_CODES

/* For the definitive definition of GIMPLE, see doc/tree-ssa.texi.  */

/* Validation of GIMPLE expressions.  */

/* Return true if OP is an acceptable tree node to be used as a GIMPLE
   operand.  */

bool
is_gimple_operand (const_tree op)
{
  return op && get_gimple_rhs_class (TREE_CODE (op)) == GIMPLE_SINGLE_RHS;
}


/* Return true if T is a GIMPLE RHS for an assignment to a temporary.  */

bool
is_gimple_formal_tmp_rhs (tree t)
{
  if (is_gimple_lvalue (t) || is_gimple_val (t))
    return true;

  return get_gimple_rhs_class (TREE_CODE (t)) != GIMPLE_INVALID_RHS;
}

/* Returns true iff T is a valid RHS for an assignment to a renamed
   user -- or front-end generated artificial -- variable.  */

bool
is_gimple_reg_rhs (tree t)
{
  /* If the RHS of the MODIFY_EXPR may throw or make a nonlocal goto
     and the LHS is a user variable, then we need to introduce a formal
     temporary.  This way the optimizers can determine that the user
     variable is only modified if evaluation of the RHS does not throw.

     Don't force a temp of a non-renamable type; the copy could be
     arbitrarily expensive.  Instead we will generate a VDEF for
     the assignment.  */

  if (is_gimple_reg_type (TREE_TYPE (t)) && tree_could_throw_p (t))
    return false;

  return is_gimple_formal_tmp_rhs (t);
}

/* Returns true iff T is a valid RHS for an assignment to an un-renamed
   LHS, or for a call argument.  */

bool
is_gimple_mem_rhs (tree t)
{
  /* If we're dealing with a renamable type, either source or dest must be
     a renamed variable.  */
  if (is_gimple_reg_type (TREE_TYPE (t)))
    return is_gimple_val (t);
  else
    return is_gimple_formal_tmp_rhs (t);
}

/*  Return true if T is a valid LHS for a GIMPLE assignment expression.  */

bool
is_gimple_lvalue (tree t)
{
  return (is_gimple_addressable (t)
          || TREE_CODE (t) == WITH_SIZE_EXPR
          /* These are complex lvalues, but don't have addresses, so they
             go here.  */
          || TREE_CODE (t) == BIT_FIELD_REF);
}

/*  Return true if T is a GIMPLE condition.  */

bool
is_gimple_condexpr (tree t)
{
  return (is_gimple_val (t) || (COMPARISON_CLASS_P (t)
                                && !tree_could_trap_p (t)
                                && is_gimple_val (TREE_OPERAND (t, 0))
                                && is_gimple_val (TREE_OPERAND (t, 1))));
}

/*  Return true if T is something whose address can be taken.  */

bool
is_gimple_addressable (tree t)
{
  return (is_gimple_id (t) || handled_component_p (t) || INDIRECT_REF_P (t));
}

/* Return true if T is a valid gimple constant.  */

bool
is_gimple_constant (const_tree t)
{
  switch (TREE_CODE (t))
    {
    case INTEGER_CST:
    case REAL_CST:
    case FIXED_CST:
    case STRING_CST:
    case COMPLEX_CST:
    case VECTOR_CST:
      return true;

    /* Vector constant constructors are gimple invariant.  */
    case CONSTRUCTOR:
      if (TREE_TYPE (t) && TREE_CODE (TREE_TYPE (t)) == VECTOR_TYPE)
        return TREE_CONSTANT (t);
      else
        return false;

    default:
      return false;
    }
}

/* Return true if T is a gimple address.  */

bool
is_gimple_address (const_tree t)
{
  tree op;

  if (TREE_CODE (t) != ADDR_EXPR)
    return false;

  op = TREE_OPERAND (t, 0);
  while (handled_component_p (op))
    {
      if ((TREE_CODE (op) == ARRAY_REF
           || TREE_CODE (op) == ARRAY_RANGE_REF)
          && !is_gimple_val (TREE_OPERAND (op, 1)))
            return false;

      op = TREE_OPERAND (op, 0);
    }

  if (CONSTANT_CLASS_P (op) || INDIRECT_REF_P (op))
    return true;

  switch (TREE_CODE (op))
    {
    case PARM_DECL:
    case RESULT_DECL:
    case LABEL_DECL:
    case FUNCTION_DECL:
    case VAR_DECL:
    case CONST_DECL:
      return true;

    default:
      return false;
    }
}

/* Strip out all handled components that produce invariant
   offsets.  */

static const_tree
strip_invariant_refs (const_tree op)
{
  while (handled_component_p (op))
    {
      switch (TREE_CODE (op))
        {
        case ARRAY_REF:
        case ARRAY_RANGE_REF:
          if (!is_gimple_constant (TREE_OPERAND (op, 1))
              || TREE_OPERAND (op, 2) != NULL_TREE
              || TREE_OPERAND (op, 3) != NULL_TREE)
            return NULL;
          break;

        case COMPONENT_REF:
          if (TREE_OPERAND (op, 2) != NULL_TREE)
            return NULL;
          break;

        default:;
        }
      op = TREE_OPERAND (op, 0);
    }

  return op;
}

/* Return true if T is a gimple invariant address.  */

bool
is_gimple_invariant_address (const_tree t)
{
  const_tree op;

  if (TREE_CODE (t) != ADDR_EXPR)
    return false;

  op = strip_invariant_refs (TREE_OPERAND (t, 0));

  return op && (CONSTANT_CLASS_P (op) || decl_address_invariant_p (op));
}

/* Return true if T is a gimple invariant address at IPA level
   (so addresses of variables on stack are not allowed).  */

bool
is_gimple_ip_invariant_address (const_tree t)
{
  const_tree op;

  if (TREE_CODE (t) != ADDR_EXPR)
    return false;

  op = strip_invariant_refs (TREE_OPERAND (t, 0));

  return op && (CONSTANT_CLASS_P (op) || decl_address_ip_invariant_p (op));
}

/* Return true if T is a GIMPLE minimal invariant.  It's a restricted
   form of function invariant.  */

bool
is_gimple_min_invariant (const_tree t)
{
  if (TREE_CODE (t) == ADDR_EXPR)
    return is_gimple_invariant_address (t);

  return is_gimple_constant (t);
}

/* Return true if T is a GIMPLE interprocedural invariant.  It's a restricted
   form of gimple minimal invariant.  */

bool
is_gimple_ip_invariant (const_tree t)
{
  if (TREE_CODE (t) == ADDR_EXPR)
    return is_gimple_ip_invariant_address (t);

  return is_gimple_constant (t);
}

/* Return true if T looks like a valid GIMPLE statement.  */

bool
is_gimple_stmt (tree t)
{
  const enum tree_code code = TREE_CODE (t);

  switch (code)
    {
    case NOP_EXPR:
      /* The only valid NOP_EXPR is the empty statement.  */
      return IS_EMPTY_STMT (t);

    case BIND_EXPR:
    case COND_EXPR:
      /* These are only valid if they're void.  */
      return TREE_TYPE (t) == NULL || VOID_TYPE_P (TREE_TYPE (t));

    case SWITCH_EXPR:
    case GOTO_EXPR:
    case RETURN_EXPR:
    case LABEL_EXPR:
    case CASE_LABEL_EXPR:
    case TRY_CATCH_EXPR:
    case TRY_FINALLY_EXPR:
    case EH_FILTER_EXPR:
    case CATCH_EXPR:
    case CHANGE_DYNAMIC_TYPE_EXPR:
    case ASM_EXPR:
    case RESX_EXPR:
    case STATEMENT_LIST:
    case OMP_PARALLEL:
    case OMP_FOR:
    case OMP_SECTIONS:
    case OMP_SECTION:
    case OMP_SINGLE:
    case OMP_MASTER:
    case OMP_ORDERED:
    case OMP_CRITICAL:
    case OMP_TASK:
      /* These are always void.  */
      return true;

    case CALL_EXPR:
    case MODIFY_EXPR:
    case PREDICT_EXPR:
      /* These are valid regardless of their type.  */
      return true;

    default:
      return false;
    }
}

/* Return true if T is a variable.  */

bool
is_gimple_variable (tree t)
{
  return (TREE_CODE (t) == VAR_DECL
          || TREE_CODE (t) == PARM_DECL
          || TREE_CODE (t) == RESULT_DECL
          || TREE_CODE (t) == SSA_NAME);
}

/*  Return true if T is a GIMPLE identifier (something with an address).  */

bool
is_gimple_id (tree t)
{
  return (is_gimple_variable (t)
          || TREE_CODE (t) == FUNCTION_DECL
          || TREE_CODE (t) == LABEL_DECL
          || TREE_CODE (t) == CONST_DECL
          /* Allow string constants, since they are addressable.  */
          || TREE_CODE (t) == STRING_CST);
}

/* Return true if TYPE is a suitable type for a scalar register variable.  */

bool
is_gimple_reg_type (tree type)
{
  /* In addition to aggregate types, we also exclude complex types if not
     optimizing because they can be subject to partial stores in GNU C by
     means of the __real__ and __imag__ operators and we cannot promote
     them to total stores (see gimplify_modify_expr_complex_part).  */
  return !(AGGREGATE_TYPE_P (type)
           || (TREE_CODE (type) == COMPLEX_TYPE && !optimize));

}

/* Return true if T is a non-aggregate register variable.  */

bool
is_gimple_reg (tree t)
{
  if (TREE_CODE (t) == SSA_NAME)
    t = SSA_NAME_VAR (t);

  if (MTAG_P (t))
    return false;

  if (!is_gimple_variable (t))
    return false;

  if (!is_gimple_reg_type (TREE_TYPE (t)))
    return false;

  /* A volatile decl is not acceptable because we can't reuse it as
     needed.  We need to copy it into a temp first.  */
  if (TREE_THIS_VOLATILE (t))
    return false;

  /* We define "registers" as things that can be renamed as needed,
     which with our infrastructure does not apply to memory.  */
  if (needs_to_live_in_memory (t))
    return false;

  /* Hard register variables are an interesting case.  For those that
     are call-clobbered, we don't know where all the calls are, since
     we don't (want to) take into account which operations will turn
     into libcalls at the rtl level.  For those that are call-saved,
     we don't currently model the fact that calls may in fact change
     global hard registers, nor do we examine ASM_CLOBBERS at the tree
     level, and so miss variable changes that might imply.  All around,
     it seems safest to not do too much optimization with these at the
     tree level at all.  We'll have to rely on the rtl optimizers to
     clean this up, as there we've got all the appropriate bits exposed.  */
  if (TREE_CODE (t) == VAR_DECL && DECL_HARD_REGISTER (t))
    return false;

  /* Complex and vector values must have been put into SSA-like form.
     That is, no assignments to the individual components.  */
  if (TREE_CODE (TREE_TYPE (t)) == COMPLEX_TYPE
      || TREE_CODE (TREE_TYPE (t)) == VECTOR_TYPE)
    return DECL_GIMPLE_REG_P (t);

  return true;
}


/* Returns true if T is a GIMPLE formal temporary variable.  */

bool
is_gimple_formal_tmp_var (tree t)
{
  if (TREE_CODE (t) == SSA_NAME)
    return true;

  return TREE_CODE (t) == VAR_DECL && DECL_GIMPLE_FORMAL_TEMP_P (t);
}

/* Returns true if T is a GIMPLE formal temporary register variable.  */

bool
is_gimple_formal_tmp_reg (tree t)
{
  /* The intent of this is to get hold of a value that won't change.
     An SSA_NAME qualifies no matter if its of a user variable or not.  */
  if (TREE_CODE (t) == SSA_NAME)
    return true;

  /* We don't know the lifetime characteristics of user variables.  */
  if (!is_gimple_formal_tmp_var (t))
    return false;

  /* Finally, it must be capable of being placed in a register.  */
  return is_gimple_reg (t);
}

/* Return true if T is a GIMPLE variable whose address is not needed.  */

bool
is_gimple_non_addressable (tree t)
{
  if (TREE_CODE (t) == SSA_NAME)
    t = SSA_NAME_VAR (t);

  return (is_gimple_variable (t) && ! needs_to_live_in_memory (t));
}

/* Return true if T is a GIMPLE rvalue, i.e. an identifier or a constant.  */

bool
is_gimple_val (tree t)
{
  /* Make loads from volatiles and memory vars explicit.  */
  if (is_gimple_variable (t)
      && is_gimple_reg_type (TREE_TYPE (t))
      && !is_gimple_reg (t))
    return false;

  /* FIXME make these decls.  That can happen only when we expose the
     entire landing-pad construct at the tree level.  */
  if (TREE_CODE (t) == EXC_PTR_EXPR || TREE_CODE (t) == FILTER_EXPR)
    return true;

  return (is_gimple_variable (t) || is_gimple_min_invariant (t));
}

/* Similarly, but accept hard registers as inputs to asm statements.  */

bool
is_gimple_asm_val (tree t)
{
  if (TREE_CODE (t) == VAR_DECL && DECL_HARD_REGISTER (t))
    return true;

  return is_gimple_val (t);
}

/* Return true if T is a GIMPLE minimal lvalue.  */

bool
is_gimple_min_lval (tree t)
{
  return (is_gimple_id (t) || TREE_CODE (t) == INDIRECT_REF);
}

/* Return true if T is a typecast operation.  */

bool
is_gimple_cast (tree t)
{
  return (CONVERT_EXPR_P (t)
          || TREE_CODE (t) == FIX_TRUNC_EXPR);
}

/* Return true if T is a valid function operand of a CALL_EXPR.  */

bool
is_gimple_call_addr (tree t)
{
  return (TREE_CODE (t) == OBJ_TYPE_REF || is_gimple_val (t));
}

/* If T makes a function call, return the corresponding CALL_EXPR operand.
   Otherwise, return NULL_TREE.  */

tree
get_call_expr_in (tree t)
{
  if (TREE_CODE (t) == MODIFY_EXPR)
    t = TREE_OPERAND (t, 1);
  if (TREE_CODE (t) == WITH_SIZE_EXPR)
    t = TREE_OPERAND (t, 0);
  if (TREE_CODE (t) == CALL_EXPR)
    return t;
  return NULL_TREE;
}


/* Given a memory reference expression T, return its base address.
   The base address of a memory reference expression is the main
   object being referenced.  For instance, the base address for
   'array[i].fld[j]' is 'array'.  You can think of this as stripping
   away the offset part from a memory address.

   This function calls handled_component_p to strip away all the inner
   parts of the memory reference until it reaches the base object.  */

tree
get_base_address (tree t)
{
  while (handled_component_p (t))
    t = TREE_OPERAND (t, 0);
  
  if (SSA_VAR_P (t)
      || TREE_CODE (t) == STRING_CST
      || TREE_CODE (t) == CONSTRUCTOR
      || INDIRECT_REF_P (t))
    return t;
  else
    return NULL_TREE;
}

void
recalculate_side_effects (tree t)
{
  enum tree_code code = TREE_CODE (t);
  int len = TREE_OPERAND_LENGTH (t);
  int i;

  switch (TREE_CODE_CLASS (code))
    {
    case tcc_expression:
      switch (code)
        {
        case INIT_EXPR:
        case MODIFY_EXPR:
        case VA_ARG_EXPR:
        case PREDECREMENT_EXPR:
        case PREINCREMENT_EXPR:
        case POSTDECREMENT_EXPR:
        case POSTINCREMENT_EXPR:
          /* All of these have side-effects, no matter what their
             operands are.  */
          return;

        default:
          break;
        }
      /* Fall through.  */

    case tcc_comparison:  /* a comparison expression */
    case tcc_unary:       /* a unary arithmetic expression */
    case tcc_binary:      /* a binary arithmetic expression */
    case tcc_reference:   /* a reference */
    case tcc_vl_exp:        /* a function call */
      TREE_SIDE_EFFECTS (t) = TREE_THIS_VOLATILE (t);
      for (i = 0; i < len; ++i)
        {
          tree op = TREE_OPERAND (t, i);
          if (op && TREE_SIDE_EFFECTS (op))
            TREE_SIDE_EFFECTS (t) = 1;
        }
      break;

    case tcc_constant:
      /* No side-effects.  */
      return;

    default:
      gcc_unreachable ();
   }
}

/* Canonicalize a tree T for use in a COND_EXPR as conditional.  Returns
   a canonicalized tree that is valid for a COND_EXPR or NULL_TREE, if
   we failed to create one.  */

tree
canonicalize_cond_expr_cond (tree t)
{
  /* For (bool)x use x != 0.  */
  if (TREE_CODE (t) == NOP_EXPR
      && TREE_TYPE (t) == boolean_type_node)
    {
      tree top0 = TREE_OPERAND (t, 0);
      t = build2 (NE_EXPR, TREE_TYPE (t),
                  top0, build_int_cst (TREE_TYPE (top0), 0));
    }
  /* For !x use x == 0.  */
  else if (TREE_CODE (t) == TRUTH_NOT_EXPR)
    {
      tree top0 = TREE_OPERAND (t, 0);
      t = build2 (EQ_EXPR, TREE_TYPE (t),
                  top0, build_int_cst (TREE_TYPE (top0), 0));
    }
  /* For cmp ? 1 : 0 use cmp.  */
  else if (TREE_CODE (t) == COND_EXPR
           && COMPARISON_CLASS_P (TREE_OPERAND (t, 0))
           && integer_onep (TREE_OPERAND (t, 1))
           && integer_zerop (TREE_OPERAND (t, 2)))
    {
      tree top0 = TREE_OPERAND (t, 0);
      t = build2 (TREE_CODE (top0), TREE_TYPE (t),
                  TREE_OPERAND (top0, 0), TREE_OPERAND (top0, 1));
    }

  if (is_gimple_condexpr (t))
    return t;

  return NULL_TREE;
}

/* Build a GIMPLE_CALL identical to STMT but skipping the arguments in
   the positions marked by the set ARGS_TO_SKIP.  */

gimple
gimple_call_copy_skip_args (gimple stmt, bitmap args_to_skip)
{
  int i;
  tree fn = gimple_call_fn (stmt);
  int nargs = gimple_call_num_args (stmt);
  VEC(tree, heap) *vargs = VEC_alloc (tree, heap, nargs);
  gimple new_stmt;

  for (i = 0; i < nargs; i++)
    if (!bitmap_bit_p (args_to_skip, i))
      VEC_quick_push (tree, vargs, gimple_call_arg (stmt, i));

  new_stmt = gimple_build_call_vec (fn, vargs);
  VEC_free (tree, heap, vargs);
  if (gimple_call_lhs (stmt))
    gimple_call_set_lhs (new_stmt, gimple_call_lhs (stmt));

  gimple_set_block (new_stmt, gimple_block (stmt));
  if (gimple_has_location (stmt))
    gimple_set_location (new_stmt, gimple_location (stmt));

  /* Carry all the flags to the new GIMPLE_CALL.  */
  gimple_call_set_chain (new_stmt, gimple_call_chain (stmt));
  gimple_call_set_tail (new_stmt, gimple_call_tail_p (stmt));
  gimple_call_set_cannot_inline (new_stmt, gimple_call_cannot_inline_p (stmt));
  gimple_call_set_return_slot_opt (new_stmt, gimple_call_return_slot_opt_p (stmt));
  gimple_call_set_from_thunk (new_stmt, gimple_call_from_thunk_p (stmt));
  gimple_call_set_va_arg_pack (new_stmt, gimple_call_va_arg_pack_p (stmt));
  return new_stmt;
}

#include "gt-gimple.h"