gimple.c (gimple_replace_lhs): Move to tree-ssa.c and rename.

[platform/upstream/gcc.git] / gcc / gimple.c

/* Gimple IR support functions.

   Copyright (C) 2007-2013 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 "target.h"
#include "tree.h"
#include "ggc.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"
#include "alias.h"
#include "demangle.h"
#include "langhooks.h"

/* Global canonical type table.  */
static GTY((if_marked ("ggc_marked_p"), param_is (union tree_node)))
  htab_t gimple_canonical_types;
static GTY((if_marked ("tree_int_map_marked_p"), param_is (struct tree_int_map)))
  htab_t canonical_type_hash_cache;

/* All the tuples have their operand vector (if present) 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 DEFGSSTRUCT(SYM, STRUCT, HAS_TREE_OP) \
        (HAS_TREE_OP ? sizeof (struct STRUCT) - sizeof (tree) : 0),
EXPORTED_CONST size_t gimple_ops_offset_[] = {
#include "gsstruct.def"
};
#undef DEFGSSTRUCT

#define DEFGSSTRUCT(SYM, STRUCT, HAS_TREE_OP) sizeof(struct STRUCT),
static const size_t gsstruct_code_size[] = {
#include "gsstruct.def"
};
#undef DEFGSSTRUCT

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

#define DEFGSCODE(SYM, NAME, GSSCODE)   GSSCODE,
EXPORTED_CONST enum gimple_statement_structure_enum gss_for_code_[] = {
#include "gimple.def"
};
#undef DEFGSCODE

/* 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",
    "everything else"
};

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

static inline size_t
gimple_size (enum gimple_code code)
{
  return gsstruct_code_size[gss_for_code (code)];
}

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

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);

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

  stmt = ggc_alloc_cleared_gimple_statement_d_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;
  gimple_init_singleton (stmt);

  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, unsigned 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, ERROR_MARK, 1);
  if (retval)
    gimple_return_set_retval (s, retval);
  return s;
}

/* Reset alias information on call S.  */

void
gimple_call_reset_alias_info (gimple s)
{
  if (gimple_call_flags (s) & ECF_CONST)
    memset (gimple_call_use_set (s), 0, sizeof (struct pt_solution));
  else
    pt_solution_reset (gimple_call_use_set (s));
  if (gimple_call_flags (s) & (ECF_CONST|ECF_PURE|ECF_NOVOPS))
    memset (gimple_call_clobber_set (s), 0, sizeof (struct pt_solution));
  else
    pt_solution_reset (gimple_call_clobber_set (s));
}

/* Helper for gimple_build_call, gimple_build_call_valist,
   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, ERROR_MARK, nargs + 3);
  if (TREE_CODE (fn) == FUNCTION_DECL)
    fn = build_fold_addr_expr (fn);
  gimple_set_op (s, 1, fn);
  gimple_call_set_fntype (s, TREE_TYPE (TREE_TYPE (fn)));
  gimple_call_reset_alias_info (s);
  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> args)
{
  unsigned i;
  unsigned nargs = args.length ();
  gimple call = gimple_build_call_1 (fn, nargs);

  for (i = 0; i < nargs; i++)
    gimple_call_set_arg (call, i, 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 to function FN.  NARGS is the number of
   arguments.  AP contains the arguments.  */

gimple
gimple_build_call_valist (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);

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

  return call;
}


/* Helper for gimple_build_call_internal and gimple_build_call_internal_vec.
   Build the basic components of a GIMPLE_CALL statement to internal
   function FN with NARGS arguments.  */

static inline gimple
gimple_build_call_internal_1 (enum internal_fn fn, unsigned nargs)
{
  gimple s = gimple_build_with_ops (GIMPLE_CALL, ERROR_MARK, nargs + 3);
  s->gsbase.subcode |= GF_CALL_INTERNAL;
  gimple_call_set_internal_fn (s, fn);
  gimple_call_reset_alias_info (s);
  return s;
}


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

gimple
gimple_build_call_internal (enum internal_fn fn, unsigned nargs, ...)
{
  va_list ap;
  gimple call;
  unsigned i;

  call = gimple_build_call_internal_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 to internal function FN with the arguments
   specified in vector ARGS.  */

gimple
gimple_build_call_internal_vec (enum internal_fn fn, vec<tree> args)
{
  unsigned i, nargs;
  gimple call;

  nargs = args.length ();
  call = gimple_build_call_internal_1 (fn, nargs);
  for (i = 0; i < nargs; i++)
    gimple_call_set_arg (call, i, args[i]);

  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_return_slot_opt (call, CALL_EXPR_RETURN_SLOT_OPT (t));
  if (fndecl
      && DECL_BUILT_IN_CLASS (fndecl) == BUILT_IN_NORMAL
      && (DECL_FUNCTION_CODE (fndecl) == BUILT_IN_ALLOCA
          || DECL_FUNCTION_CODE (fndecl) == BUILT_IN_ALLOCA_WITH_ALIGN))
    gimple_call_set_alloca_for_var (call, CALL_ALLOCA_FOR_VAR_P (t));
  else
    gimple_call_set_from_thunk (call, CALL_FROM_THUNK_P (t));
  gimple_call_set_va_arg_pack (call, CALL_EXPR_VA_ARG_PACK (t));
  gimple_call_set_nothrow (call, TREE_NOTHROW (t));
  gimple_set_no_warning (call, TREE_NO_WARNING (t));

  return call;
}


/* Extract the operands and code for expression EXPR into *SUBCODE_P,
   *OP1_P, *OP2_P and *OP3_P respectively.  */

void
extract_ops_from_tree_1 (tree expr, enum tree_code *subcode_p, tree *op1_p,
                         tree *op2_p, tree *op3_p)
{
  enum gimple_rhs_class grhs_class;

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

  if (grhs_class == GIMPLE_TERNARY_RHS)
    {
      *op1_p = TREE_OPERAND (expr, 0);
      *op2_p = TREE_OPERAND (expr, 1);
      *op3_p = TREE_OPERAND (expr, 2);
    }
  else if (grhs_class == GIMPLE_BINARY_RHS)
    {
      *op1_p = TREE_OPERAND (expr, 0);
      *op2_p = TREE_OPERAND (expr, 1);
      *op3_p = NULL_TREE;
    }
  else if (grhs_class == GIMPLE_UNARY_RHS)
    {
      *op1_p = TREE_OPERAND (expr, 0);
      *op2_p = NULL_TREE;
      *op3_p = NULL_TREE;
    }
  else if (grhs_class == GIMPLE_SINGLE_RHS)
    {
      *op1_p = expr;
      *op2_p = NULL_TREE;
      *op3_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, op3;

  extract_ops_from_tree_1 (rhs, &subcode, &op1, &op2, &op3);
  return gimple_build_assign_with_ops (subcode, lhs, op1, op2, op3
                                       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 (enum tree_code subcode, tree lhs, tree op1,
                              tree op2, tree op3 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, (unsigned)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);
    }

  if (op3)
    {
      gcc_assert (num_ops > 3);
      gimple_assign_set_rhs3 (p, op3);
    }

  return p;
}

gimple
gimple_build_assign_with_ops (enum tree_code subcode, tree lhs, tree op1,
                              tree op2 MEM_STAT_DECL)
{
  return gimple_build_assign_with_ops (subcode, lhs, op1, op2, NULL_TREE
                                       PASS_MEM_STAT);
}


/* 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.  */

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 = build_zero_cst (TREE_TYPE (*lhs_p));
    }
  /* 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 = build_zero_cst (TREE_TYPE (*lhs_p));
    }
}


/* 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, ERROR_MARK, 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, ERROR_MARK, 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, unsigned nlabels)
{
  gimple p;
  int size = strlen (string);

  /* ASMs with labels cannot have outputs.  This should have been
     enforced by the front end.  */
  gcc_assert (nlabels == 0 || noutputs == 0);

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

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

  if (GATHER_STATISTICS)
    gimple_alloc_sizes[(int) gimple_alloc_kind (GIMPLE_ASM)] += size;

  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.
   LABELS is a vector of destination labels.  */

gimple
gimple_build_asm_vec (const char *string, vec<tree, va_gc> *inputs,
                      vec<tree, va_gc> *outputs, vec<tree, va_gc> *clobbers,
                      vec<tree, va_gc> *labels)
{
  gimple p;
  unsigned i;

  p = gimple_build_asm_1 (string,
                          vec_safe_length (inputs),
                          vec_safe_length (outputs),
                          vec_safe_length (clobbers),
                          vec_safe_length (labels));

  for (i = 0; i < vec_safe_length (inputs); i++)
    gimple_asm_set_input_op (p, i, (*inputs)[i]);

  for (i = 0; i < vec_safe_length (outputs); i++)
    gimple_asm_set_output_op (p, i, (*outputs)[i]);

  for (i = 0; i < vec_safe_length (clobbers); i++)
    gimple_asm_set_clobber_op (p, i, (*clobbers)[i]);

  for (i = 0; i < vec_safe_length (labels); i++)
    gimple_asm_set_label_op (p, i, (*labels)[i]);

  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_EH_MUST_NOT_THROW statement.  */

gimple
gimple_build_eh_must_not_throw (tree decl)
{
  gimple p = gimple_alloc (GIMPLE_EH_MUST_NOT_THROW, 0);

  gcc_assert (TREE_CODE (decl) == FUNCTION_DECL);
  gcc_assert (flags_from_decl_or_type (decl) & ECF_NORETURN);
  gimple_eh_must_not_throw_set_fndecl (p, decl);

  return p;
}

/* Build a GIMPLE_EH_ELSE statement.  */

gimple
gimple_build_eh_else (gimple_seq n_body, gimple_seq e_body)
{
  gimple p = gimple_alloc (GIMPLE_EH_ELSE, 0);
  gimple_eh_else_set_n_body (p, n_body);
  gimple_eh_else_set_e_body (p, e_body);
  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.  */

gimple
gimple_build_resx (int region)
{
  gimple p = gimple_build_with_ops (GIMPLE_RESX, ERROR_MARK, 0);
  p->gimple_eh_ctrl.region = 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.  */

gimple
gimple_build_switch_nlabels (unsigned nlabels, tree index, tree default_label)
{
  /* nlabels + 1 default label + 1 index.  */
  gcc_checking_assert (default_label);
  gimple p = gimple_build_with_ops (GIMPLE_SWITCH, ERROR_MARK,
                                    1 + 1 + nlabels);
  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.
   DEFAULT_LABEL is the default label
   ARGS is a vector of labels excluding the default.  */

gimple
gimple_build_switch (tree index, tree default_label, vec<tree> args)
{
  unsigned i, nlabels = args.length ();

  gimple p = gimple_build_switch_nlabels (nlabels, index, default_label);

  /* Copy the labels from the vector to the switch statement.  */
  for (i = 0; i < nlabels; i++)
    gimple_switch_set_label (p, i + 1, args[i]);

  return p;
}

/* Build a GIMPLE_EH_DISPATCH statement.  */

gimple
gimple_build_eh_dispatch (int region)
{
  gimple p = gimple_build_with_ops (GIMPLE_EH_DISPATCH, ERROR_MARK, 0);
  p->gimple_eh_ctrl.region = region;
  return p;
}

/* Build a new GIMPLE_DEBUG_BIND statement.

   VAR is bound to VALUE; block and location are taken from STMT.  */

gimple
gimple_build_debug_bind_stat (tree var, tree value, gimple stmt MEM_STAT_DECL)
{
  gimple p = gimple_build_with_ops_stat (GIMPLE_DEBUG,
                                         (unsigned)GIMPLE_DEBUG_BIND, 2
                                         PASS_MEM_STAT);

  gimple_debug_bind_set_var (p, var);
  gimple_debug_bind_set_value (p, value);
  if (stmt)
    gimple_set_location (p, gimple_location (stmt));

  return p;
}


/* Build a new GIMPLE_DEBUG_SOURCE_BIND statement.

   VAR is bound to VALUE; block and location are taken from STMT.  */

gimple
gimple_build_debug_source_bind_stat (tree var, tree value,
                                     gimple stmt MEM_STAT_DECL)
{
  gimple p = gimple_build_with_ops_stat (GIMPLE_DEBUG,
                                         (unsigned)GIMPLE_DEBUG_SOURCE_BIND, 2
                                         PASS_MEM_STAT);

  gimple_debug_source_bind_set_var (p, var);
  gimple_debug_source_bind_set_value (p, value);
  if (stmt)
    gimple_set_location (p, gimple_location (stmt));

  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.
   KIND is the `for' variant.
   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, int kind, 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);
  gimple_omp_for_set_kind (p, kind);
  p->gimple_omp_for.collapse = collapse;
  p->gimple_omp_for.iter
      = ggc_alloc_cleared_vec_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_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_TRANSACTION statement.  */

gimple
gimple_build_transaction (gimple_seq body, tree label)
{
  gimple p = gimple_alloc (GIMPLE_TRANSACTION, 0);
  gimple_transaction_set_body (p, body);
  gimple_transaction_set_label (p, label);
  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;
}

#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 */


/* 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;

  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;

  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))
        && !is_gimple_debug (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 = NULL;
  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 *PSEQ 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, and the
   value is stored in WI->CALLBACK_RESULT.  Also, the statement that
   produced the value is returned if this statement has not been
   removed by a callback (wi->removed_stmt).  If the statement has
   been removed, NULL is returned.

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

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

  for (gsi = gsi_start (*pseq); !gsi_end_p (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 wi->removed_stmt ? NULL : gsi_stmt (gsi);
        }

      if (!wi->removed_stmt)
        gsi_next (&gsi);
    }

  if (wi)
    wi->callback_result = NULL_TREE;

  return NULL;
}


/* Like walk_gimple_seq_mod, but ensure that the head of SEQ isn't
   changed by the callbacks.  */

gimple
walk_gimple_seq (gimple_seq seq, walk_stmt_fn callback_stmt,
                 walk_tree_fn callback_op, struct walk_stmt_info *wi)
{
  gimple_seq seq2 = seq;
  gimple ret = walk_gimple_seq_mod (&seq2, callback_stmt, callback_op, wi);
  gcc_assert (seq2 == seq);
  return ret;
}


/* 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, op;
  unsigned noutputs;
  const char **oconstraints;
  unsigned i, n;
  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++)
    {
      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;
    }

  n = gimple_asm_ninputs (stmt);
  for (i = 0; i < n; i++)
    {
      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.  */
          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;
    }

  n = gimple_asm_nlabels (stmt);
  for (i = 0; i < n; i++)
    {
      op = gimple_asm_label_op (stmt, i);
      ret = walk_tree (&TREE_VALUE (op), callback_op, wi, NULL);
      if (ret)
        return ret;
    }

  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.  */

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.  If the LHS is of a non-renamable type or
         is a register variable, we may use a COMPONENT_REF on the RHS.  */
      if (wi)
        {
          tree lhs = gimple_assign_lhs (stmt);
          wi->val_only
            = (is_gimple_reg_type (TREE_TYPE (lhs)) && !is_gimple_reg (lhs))
              || gimple_assign_rhs_class (stmt) != GIMPLE_SINGLE_RHS;
        }

      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 is of a non-renamable type or is a register variable,
             we may use a COMPONENT_REF on the LHS.  */
          tree rhs1 = gimple_assign_rhs1 (stmt);
          wi->val_only
            = (is_gimple_reg_type (TREE_TYPE (rhs1)) && !is_gimple_reg (rhs1))
              || gimple_assign_rhs_class (stmt) != GIMPLE_SINGLE_RHS;
          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;
          wi->val_only = true;
        }

      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++)
        {
          if (wi)
            wi->val_only
              = is_gimple_reg_type (TREE_TYPE (gimple_call_arg (stmt, i)));
          ret = walk_tree (gimple_call_arg_ptr (stmt, i), callback_op, wi,
                           pset);
          if (ret)
            return ret;
        }

      if (gimple_call_lhs (stmt))
        {
          if (wi)
            {
              wi->is_lhs = true;
              wi->val_only
                = is_gimple_reg_type (TREE_TYPE (gimple_call_lhs (stmt)));
            }

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

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

    case GIMPLE_TRANSACTION:
      ret = walk_tree (gimple_transaction_label_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;
      wi->removed_stmt = false;

      if (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);

      if (wi && wi->removed_stmt)
        return 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_mod (gimple_bind_body_ptr (stmt), callback_stmt,
                                 callback_op, wi);
      if (ret)
        return wi->callback_result;
      break;

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

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

    case GIMPLE_EH_ELSE:
      ret = walk_gimple_seq_mod (gimple_eh_else_n_body_ptr (stmt),
                             callback_stmt, callback_op, wi);
      if (ret)
        return wi->callback_result;
      ret = walk_gimple_seq_mod (gimple_eh_else_e_body_ptr (stmt),
                             callback_stmt, callback_op, wi);
      if (ret)
        return wi->callback_result;
      break;

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

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

    case GIMPLE_OMP_FOR:
      ret = walk_gimple_seq_mod (gimple_omp_for_pre_body_ptr (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_mod (gimple_omp_body_ptr (stmt), callback_stmt,
                             callback_op, wi);
      if (ret)
        return wi->callback_result;
      break;

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

    case GIMPLE_TRANSACTION:
      ret = walk_gimple_seq_mod (gimple_transaction_body_ptr (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.  After the
   CFG pass, the function body doesn't exist anymore because it has
   been split up into basic blocks.  In this case, it returns
   NULL.  */

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));
}

/* Return true if calls C1 and C2 are known to go to the same function.  */

bool
gimple_call_same_target_p (const_gimple c1, const_gimple c2)
{
  if (gimple_call_internal_p (c1))
    return (gimple_call_internal_p (c2)
            && gimple_call_internal_fn (c1) == gimple_call_internal_fn (c2));
  else
    return (gimple_call_fn (c1) == gimple_call_fn (c2)
            || (gimple_call_fndecl (c1)
                && gimple_call_fndecl (c1) == gimple_call_fndecl (c2)));
}

/* 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);

  if (decl)
    flags = flags_from_decl_or_type (decl);
  else if (gimple_call_internal_p (stmt))
    flags = internal_fn_flags (gimple_call_internal_fn (stmt));
  else
    flags = flags_from_decl_or_type (gimple_call_fntype (stmt));

  if (stmt->gsbase.subcode & GF_CALL_NOTHROW)
    flags |= ECF_NOTHROW;

  return flags;
}

/* Return the "fn spec" string for call STMT.  */

static tree
gimple_call_fnspec (const_gimple stmt)
{
  tree type, attr;

  type = gimple_call_fntype (stmt);
  if (!type)
    return NULL_TREE;

  attr = lookup_attribute ("fn spec", TYPE_ATTRIBUTES (type));
  if (!attr)
    return NULL_TREE;

  return TREE_VALUE (TREE_VALUE (attr));
}

/* Detects argument flags for argument number ARG on call STMT.  */

int
gimple_call_arg_flags (const_gimple stmt, unsigned arg)
{
  tree attr = gimple_call_fnspec (stmt);

  if (!attr || 1 + arg >= (unsigned) TREE_STRING_LENGTH (attr))
    return 0;

  switch (TREE_STRING_POINTER (attr)[1 + arg])
    {
    case 'x':
    case 'X':
      return EAF_UNUSED;

    case 'R':
      return EAF_DIRECT | EAF_NOCLOBBER | EAF_NOESCAPE;

    case 'r':
      return EAF_NOCLOBBER | EAF_NOESCAPE;

    case 'W':
      return EAF_DIRECT | EAF_NOESCAPE;

    case 'w':
      return EAF_NOESCAPE;

    case '.':
    default:
      return 0;
    }
}

/* Detects return flags for the call STMT.  */

int
gimple_call_return_flags (const_gimple stmt)
{
  tree attr;

  if (gimple_call_flags (stmt) & ECF_MALLOC)
    return ERF_NOALIAS;

  attr = gimple_call_fnspec (stmt);
  if (!attr || TREE_STRING_LENGTH (attr) < 1)
    return 0;

  switch (TREE_STRING_POINTER (attr)[0])
    {
    case '1':
    case '2':
    case '3':
    case '4':
      return ERF_RETURNS_ARG | (TREE_STRING_POINTER (attr)[0] - '1');

    case 'm':
      return ERF_NOALIAS;

    case '.':
    default:
      return 0;
    }
}


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

bool
gimple_assign_copy_p (gimple gs)
{
  return (gimple_assign_single_p (gs)
          && 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_assign_single_p (gs)
          && 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 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 (is_gimple_assign (gs)
          && (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_safe_length (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 + 1;

              vec_safe_grow_cleared (label_to_block_map, new_len);
            }
        }

      (*label_to_block_map)[uid] = bb;
    }
}


/* 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, op3;

  extract_ops_from_tree_1 (expr, &subcode, &op1, &op2, &op3);
  gimple_assign_set_rhs_with_ops_1 (gsi, subcode, op1, op2, op3);
}


/* Set the RHS of assignment statement pointed-to by GSI to CODE with
   operands OP1, OP2 and OP3.

   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_1 (gimple_stmt_iterator *gsi, enum tree_code code,
                                  tree op1, tree op2, tree op3)
{
  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)));
      gimple_init_singleton (new_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);
  if (new_rhs_ops > 2)
    gimple_assign_set_rhs3 (stmt, op3);
}


/* 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.  The new
   copy isn't part of any sequence.  */

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));
  gimple_init_singleton (copy);

  /* 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_EH_ELSE:
          new_seq = gimple_seq_copy (gimple_eh_else_n_body (stmt));
          gimple_eh_else_set_n_body (copy, new_seq);
          new_seq = gimple_seq_copy (gimple_eh_else_e_body (stmt));
          gimple_eh_else_set_e_body (copy, new_seq);
          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_alloc_vec_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_TRANSACTION:
          new_seq = gimple_seq_copy (gimple_transaction_body (stmt));
          gimple_transaction_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.  */
  for (i = 0; i < num_ops; i++)
    gimple_set_op (copy, i, unshare_expr (gimple_op (stmt, i)));

  if (gimple_has_mem_ops (stmt))
    {
      gimple_set_vdef (copy, gimple_vdef (stmt));
      gimple_set_vuse (copy, gimple_vuse (stmt));
    }

  /* Clear out SSA operand vectors on COPY.  */
  if (gimple_has_ops (stmt))
    {
      gimple_set_use_ops (copy, NULL);

      /* SSA operands need to be updated.  */
      gimple_set_modified (copy, true);
    }

  return copy;
}


/* 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)
{
  if (is_gimple_debug (s))
    return false;

  /* 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 (gimple_code (s) == GIMPLE_ASM
      && gimple_asm_volatile_p (s))
    return true;

  if (is_gimple_call (s))
    {
      int flags = gimple_call_flags (s);

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

      return false;
    }

  return false;
}

/* Helper for gimple_could_trap_p and gimple_assign_rhs_could_trap_p.
   Return true if S can trap.  When INCLUDE_MEM is true, check whether
   the memory operations could trap.  When INCLUDE_STORES is true and
   S is a GIMPLE_ASSIGN, the LHS of the assignment is also checked.  */

bool
gimple_could_trap_p_1 (gimple s, bool include_mem, bool include_stores)
{
  tree t, div = NULL_TREE;
  enum tree_code op;

  if (include_mem)
    {
      unsigned i, start = (is_gimple_assign (s) && !include_stores) ? 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, 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, true, false);
}


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

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

  if (! GATHER_STATISTICS)
    {
      fprintf (stderr, "No gimple statistics\n");
      return;
    }

  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");
}


/* 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 if (rhs_class == GIMPLE_TERNARY_RHS)
    return 3;
  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) == WIDEN_MULT_PLUS_EXPR                                      \
      || (SYM) == WIDEN_MULT_MINUS_EXPR                                     \
      || (SYM) == DOT_PROD_EXPR                                             \
      || (SYM) == REALIGN_LOAD_EXPR                                         \
      || (SYM) == VEC_COND_EXPR                                             \
      || (SYM) == VEC_PERM_EXPR                                             \
      || (SYM) == FMA_EXPR) ? GIMPLE_TERNARY_RHS                            \
   : ((SYM) == CONSTRUCTOR                                                  \
      || (SYM) == OBJ_TYPE_REF                                              \
      || (SYM) == ASSERT_EXPR                                               \
      || (SYM) == ADDR_EXPR                                                 \
      || (SYM) == WITH_SIZE_EXPR                                            \
      || (SYM) == SSA_NAME) ? 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 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_throw_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)
          || TREE_CODE (t) == MEM_REF);
}

/* 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;

    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) || TREE_CODE (op) == MEM_REF)
    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;
    }
}

/* 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));
  if (!op)
    return false;

  if (TREE_CODE (op) == MEM_REF)
    {
      const_tree op0 = TREE_OPERAND (op, 0);
      return (TREE_CODE (op0) == ADDR_EXPR
              && (CONSTANT_CLASS_P (TREE_OPERAND (op0, 0))
                  || decl_address_invariant_p (TREE_OPERAND (op0, 0))));
    }

  return 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));
  if (!op)
    return false;

  if (TREE_CODE (op) == MEM_REF)
    {
      const_tree op0 = TREE_OPERAND (op, 0);
      return (TREE_CODE (op0) == ADDR_EXPR
              && (CONSTANT_CLASS_P (TREE_OPERAND (op0, 0))
                  || decl_address_ip_invariant_p (TREE_OPERAND (op0, 0))));
    }

  return 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 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 T is a non-aggregate register variable.  */

bool
is_gimple_reg (tree t)
{
  if (virtual_operand_p (t))
    return false;

  if (TREE_CODE (t) == SSA_NAME)
    return true;

  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;
}


/* 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;

  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)
{
  if (!(t = CONST_CAST_TREE (strip_invariant_refs (t))))
    return false;
  return (is_gimple_id (t) || TREE_CODE (t) == MEM_REF);
}

/* 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));
}

/* Return true if T is a valid address operand of a MEM_REF.  */

bool
is_gimple_mem_ref_addr (tree t)
{
  return (is_gimple_reg (t)
          || TREE_CODE (t) == INTEGER_CST
          || (TREE_CODE (t) == ADDR_EXPR
              && (CONSTANT_CLASS_P (TREE_OPERAND (t, 0))
                  || decl_address_invariant_p (TREE_OPERAND (t, 0)))));
}


/* 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 ((TREE_CODE (t) == MEM_REF
       || TREE_CODE (t) == TARGET_MEM_REF)
      && TREE_CODE (TREE_OPERAND (t, 0)) == ADDR_EXPR)
    t = TREE_OPERAND (TREE_OPERAND (t, 0), 0);

  /* ???  Either the alias oracle or all callers need to properly deal
     with WITH_SIZE_EXPRs before we can look through those.  */
  if (TREE_CODE (t) == WITH_SIZE_EXPR)
    return NULL_TREE;

  return t;
}

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)
{
  /* Strip conversions around boolean operations.  */
  if (CONVERT_EXPR_P (t)
      && (truth_value_p (TREE_CODE (TREE_OPERAND (t, 0)))
          || TREE_CODE (TREE_TYPE (TREE_OPERAND (t, 0)))
             == BOOLEAN_TYPE))
    t = TREE_OPERAND (t, 0);

  /* For !x use x == 0.  */
  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));
    }
  /* For x ^ y use x != y.  */
  else if (TREE_CODE (t) == BIT_XOR_EXPR)
    t = build2 (NE_EXPR, TREE_TYPE (t),
                TREE_OPERAND (t, 0), TREE_OPERAND (t, 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;
  int nargs = gimple_call_num_args (stmt);
  vec<tree> vargs;
  vargs.create (nargs);
  gimple new_stmt;

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

  if (gimple_call_internal_p (stmt))
    new_stmt = gimple_build_call_internal_vec (gimple_call_internal_fn (stmt),
                                               vargs);
  else
    new_stmt = gimple_build_call_vec (gimple_call_fn (stmt), vargs);
  vargs.release ();
  if (gimple_call_lhs (stmt))
    gimple_call_set_lhs (new_stmt, gimple_call_lhs (stmt));

  gimple_set_vuse (new_stmt, gimple_vuse (stmt));
  gimple_set_vdef (new_stmt, gimple_vdef (stmt));

  if (gimple_has_location (stmt))
    gimple_set_location (new_stmt, gimple_location (stmt));
  gimple_call_copy_flags (new_stmt, stmt);
  gimple_call_set_chain (new_stmt, gimple_call_chain (stmt));

  gimple_set_modified (new_stmt, true);

  return new_stmt;
}



/* Return true if the field decls F1 and F2 are at the same offset.

   This is intended to be used on GIMPLE types only.  */

bool
gimple_compare_field_offset (tree f1, tree f2)
{
  if (DECL_OFFSET_ALIGN (f1) == DECL_OFFSET_ALIGN (f2))
    {
      tree offset1 = DECL_FIELD_OFFSET (f1);
      tree offset2 = DECL_FIELD_OFFSET (f2);
      return ((offset1 == offset2
               /* Once gimplification is done, self-referential offsets are
                  instantiated as operand #2 of the COMPONENT_REF built for
                  each access and reset.  Therefore, they are not relevant
                  anymore and fields are interchangeable provided that they
                  represent the same access.  */
               || (TREE_CODE (offset1) == PLACEHOLDER_EXPR
                   && TREE_CODE (offset2) == PLACEHOLDER_EXPR
                   && (DECL_SIZE (f1) == DECL_SIZE (f2)
                       || (TREE_CODE (DECL_SIZE (f1)) == PLACEHOLDER_EXPR
                           && TREE_CODE (DECL_SIZE (f2)) == PLACEHOLDER_EXPR)
                       || operand_equal_p (DECL_SIZE (f1), DECL_SIZE (f2), 0))
                   && DECL_ALIGN (f1) == DECL_ALIGN (f2))
               || operand_equal_p (offset1, offset2, 0))
              && tree_int_cst_equal (DECL_FIELD_BIT_OFFSET (f1),
                                     DECL_FIELD_BIT_OFFSET (f2)));
    }

  /* Fortran and C do not always agree on what DECL_OFFSET_ALIGN
     should be, so handle differing ones specially by decomposing
     the offset into a byte and bit offset manually.  */
  if (host_integerp (DECL_FIELD_OFFSET (f1), 0)
      && host_integerp (DECL_FIELD_OFFSET (f2), 0))
    {
      unsigned HOST_WIDE_INT byte_offset1, byte_offset2;
      unsigned HOST_WIDE_INT bit_offset1, bit_offset2;
      bit_offset1 = TREE_INT_CST_LOW (DECL_FIELD_BIT_OFFSET (f1));
      byte_offset1 = (TREE_INT_CST_LOW (DECL_FIELD_OFFSET (f1))
                      + bit_offset1 / BITS_PER_UNIT);
      bit_offset2 = TREE_INT_CST_LOW (DECL_FIELD_BIT_OFFSET (f2));
      byte_offset2 = (TREE_INT_CST_LOW (DECL_FIELD_OFFSET (f2))
                      + bit_offset2 / BITS_PER_UNIT);
      if (byte_offset1 != byte_offset2)
        return false;
      return bit_offset1 % BITS_PER_UNIT == bit_offset2 % BITS_PER_UNIT;
    }

  return false;
}

/* Returning a hash value for gimple type TYPE combined with VAL.

   The hash value returned is equal for types considered compatible
   by gimple_canonical_types_compatible_p.  */

static hashval_t
iterative_hash_canonical_type (tree type, hashval_t val)
{
  hashval_t v;
  void **slot;
  struct tree_int_map *mp, m;

  m.base.from = type;
  if ((slot = htab_find_slot (canonical_type_hash_cache, &m, INSERT))
      && *slot)
    return iterative_hash_hashval_t (((struct tree_int_map *) *slot)->to, val);

  /* Combine a few common features of types so that types are grouped into
     smaller sets; when searching for existing matching types to merge,
     only existing types having the same features as the new type will be
     checked.  */
  v = iterative_hash_hashval_t (TREE_CODE (type), 0);
  v = iterative_hash_hashval_t (TREE_ADDRESSABLE (type), v);
  v = iterative_hash_hashval_t (TYPE_ALIGN (type), v);
  v = iterative_hash_hashval_t (TYPE_MODE (type), v);

  /* Incorporate common features of numerical types.  */
  if (INTEGRAL_TYPE_P (type)
      || SCALAR_FLOAT_TYPE_P (type)
      || FIXED_POINT_TYPE_P (type)
      || TREE_CODE (type) == OFFSET_TYPE
      || POINTER_TYPE_P (type))
    {
      v = iterative_hash_hashval_t (TYPE_PRECISION (type), v);
      v = iterative_hash_hashval_t (TYPE_UNSIGNED (type), v);
    }

  if (VECTOR_TYPE_P (type))
    {
      v = iterative_hash_hashval_t (TYPE_VECTOR_SUBPARTS (type), v);
      v = iterative_hash_hashval_t (TYPE_UNSIGNED (type), v);
    }

  if (TREE_CODE (type) == COMPLEX_TYPE)
    v = iterative_hash_hashval_t (TYPE_UNSIGNED (type), v);

  /* For pointer and reference types, fold in information about the type
     pointed to but do not recurse to the pointed-to type.  */
  if (POINTER_TYPE_P (type))
    {
      v = iterative_hash_hashval_t (TYPE_REF_CAN_ALIAS_ALL (type), v);
      v = iterative_hash_hashval_t (TYPE_ADDR_SPACE (TREE_TYPE (type)), v);
      v = iterative_hash_hashval_t (TYPE_RESTRICT (type), v);
      v = iterative_hash_hashval_t (TREE_CODE (TREE_TYPE (type)), v);
    }

  /* For integer types hash only the string flag.  */
  if (TREE_CODE (type) == INTEGER_TYPE)
    v = iterative_hash_hashval_t (TYPE_STRING_FLAG (type), v);

  /* For array types hash the domain bounds and the string flag.  */
  if (TREE_CODE (type) == ARRAY_TYPE && TYPE_DOMAIN (type))
    {
      v = iterative_hash_hashval_t (TYPE_STRING_FLAG (type), v);
      /* OMP lowering can introduce error_mark_node in place of
         random local decls in types.  */
      if (TYPE_MIN_VALUE (TYPE_DOMAIN (type)) != error_mark_node)
        v = iterative_hash_expr (TYPE_MIN_VALUE (TYPE_DOMAIN (type)), v);
      if (TYPE_MAX_VALUE (TYPE_DOMAIN (type)) != error_mark_node)
        v = iterative_hash_expr (TYPE_MAX_VALUE (TYPE_DOMAIN (type)), v);
    }

  /* Recurse for aggregates with a single element type.  */
  if (TREE_CODE (type) == ARRAY_TYPE
      || TREE_CODE (type) == COMPLEX_TYPE
      || TREE_CODE (type) == VECTOR_TYPE)
    v = iterative_hash_canonical_type (TREE_TYPE (type), v);

  /* Incorporate function return and argument types.  */
  if (TREE_CODE (type) == FUNCTION_TYPE || TREE_CODE (type) == METHOD_TYPE)
    {
      unsigned na;
      tree p;

      /* For method types also incorporate their parent class.  */
      if (TREE_CODE (type) == METHOD_TYPE)
        v = iterative_hash_canonical_type (TYPE_METHOD_BASETYPE (type), v);

      v = iterative_hash_canonical_type (TREE_TYPE (type), v);

      for (p = TYPE_ARG_TYPES (type), na = 0; p; p = TREE_CHAIN (p))
        {
          v = iterative_hash_canonical_type (TREE_VALUE (p), v);
          na++;
        }

      v = iterative_hash_hashval_t (na, v);
    }

  if (RECORD_OR_UNION_TYPE_P (type))
    {
      unsigned nf;
      tree f;

      for (f = TYPE_FIELDS (type), nf = 0; f; f = TREE_CHAIN (f))
        if (TREE_CODE (f) == FIELD_DECL)
          {
            v = iterative_hash_canonical_type (TREE_TYPE (f), v);
            nf++;
          }

      v = iterative_hash_hashval_t (nf, v);
    }

  /* Cache the just computed hash value.  */
  mp = ggc_alloc_cleared_tree_int_map ();
  mp->base.from = type;
  mp->to = v;
  *slot = (void *) mp;

  return iterative_hash_hashval_t (v, val);
}

static hashval_t
gimple_canonical_type_hash (const void *p)
{
  if (canonical_type_hash_cache == NULL)
    canonical_type_hash_cache = htab_create_ggc (512, tree_int_map_hash,
                                                 tree_int_map_eq, NULL);

  return iterative_hash_canonical_type (CONST_CAST_TREE ((const_tree) p), 0);
}




/* The TYPE_CANONICAL merging machinery.  It should closely resemble
   the middle-end types_compatible_p function.  It needs to avoid
   claiming types are different for types that should be treated
   the same with respect to TBAA.  Canonical types are also used
   for IL consistency checks via the useless_type_conversion_p
   predicate which does not handle all type kinds itself but falls
   back to pointer-comparison of TYPE_CANONICAL for aggregates
   for example.  */

/* Return true iff T1 and T2 are structurally identical for what
   TBAA is concerned.  */

static bool
gimple_canonical_types_compatible_p (tree t1, tree t2)
{
  /* Before starting to set up the SCC machinery handle simple cases.  */

  /* Check first for the obvious case of pointer identity.  */
  if (t1 == t2)
    return true;

  /* Check that we have two types to compare.  */
  if (t1 == NULL_TREE || t2 == NULL_TREE)
    return false;

  /* If the types have been previously registered and found equal
     they still are.  */
  if (TYPE_CANONICAL (t1)
      && TYPE_CANONICAL (t1) == TYPE_CANONICAL (t2))
    return true;

  /* Can't be the same type if the types don't have the same code.  */
  if (TREE_CODE (t1) != TREE_CODE (t2))
    return false;

  if (TREE_ADDRESSABLE (t1) != TREE_ADDRESSABLE (t2))
    return false;

  /* Qualifiers do not matter for canonical type comparison purposes.  */

  /* Void types and nullptr types are always the same.  */
  if (TREE_CODE (t1) == VOID_TYPE
      || TREE_CODE (t1) == NULLPTR_TYPE)
    return true;

  /* Can't be the same type if they have different alignment, or mode.  */
  if (TYPE_ALIGN (t1) != TYPE_ALIGN (t2)
      || TYPE_MODE (t1) != TYPE_MODE (t2))
    return false;

  /* Non-aggregate types can be handled cheaply.  */
  if (INTEGRAL_TYPE_P (t1)
      || SCALAR_FLOAT_TYPE_P (t1)
      || FIXED_POINT_TYPE_P (t1)
      || TREE_CODE (t1) == VECTOR_TYPE
      || TREE_CODE (t1) == COMPLEX_TYPE
      || TREE_CODE (t1) == OFFSET_TYPE
      || POINTER_TYPE_P (t1))
    {
      /* Can't be the same type if they have different sign or precision.  */
      if (TYPE_PRECISION (t1) != TYPE_PRECISION (t2)
          || TYPE_UNSIGNED (t1) != TYPE_UNSIGNED (t2))
        return false;

      if (TREE_CODE (t1) == INTEGER_TYPE
          && TYPE_STRING_FLAG (t1) != TYPE_STRING_FLAG (t2))
        return false;

      /* For canonical type comparisons we do not want to build SCCs
         so we cannot compare pointed-to types.  But we can, for now,
         require the same pointed-to type kind and match what
         useless_type_conversion_p would do.  */
      if (POINTER_TYPE_P (t1))
        {
          /* If the two pointers have different ref-all attributes,
             they can't be the same type.  */
          if (TYPE_REF_CAN_ALIAS_ALL (t1) != TYPE_REF_CAN_ALIAS_ALL (t2))
            return false;

          if (TYPE_ADDR_SPACE (TREE_TYPE (t1))
              != TYPE_ADDR_SPACE (TREE_TYPE (t2)))
            return false;

          if (TYPE_RESTRICT (t1) != TYPE_RESTRICT (t2))
            return false;

          if (TREE_CODE (TREE_TYPE (t1)) != TREE_CODE (TREE_TYPE (t2)))
            return false;
        }

      /* Tail-recurse to components.  */
      if (TREE_CODE (t1) == VECTOR_TYPE
          || TREE_CODE (t1) == COMPLEX_TYPE)
        return gimple_canonical_types_compatible_p (TREE_TYPE (t1),
                                                    TREE_TYPE (t2));

      return true;
    }

  /* Do type-specific comparisons.  */
  switch (TREE_CODE (t1))
    {
    case ARRAY_TYPE:
      /* Array types are the same if the element types are the same and
         the number of elements are the same.  */
      if (!gimple_canonical_types_compatible_p (TREE_TYPE (t1), TREE_TYPE (t2))
          || TYPE_STRING_FLAG (t1) != TYPE_STRING_FLAG (t2)
          || TYPE_NONALIASED_COMPONENT (t1) != TYPE_NONALIASED_COMPONENT (t2))
        return false;
      else
        {
          tree i1 = TYPE_DOMAIN (t1);
          tree i2 = TYPE_DOMAIN (t2);

          /* For an incomplete external array, the type domain can be
             NULL_TREE.  Check this condition also.  */
          if (i1 == NULL_TREE && i2 == NULL_TREE)
            return true;
          else if (i1 == NULL_TREE || i2 == NULL_TREE)
            return false;
          else
            {
              tree min1 = TYPE_MIN_VALUE (i1);
              tree min2 = TYPE_MIN_VALUE (i2);
              tree max1 = TYPE_MAX_VALUE (i1);
              tree max2 = TYPE_MAX_VALUE (i2);

              /* The minimum/maximum values have to be the same.  */
              if ((min1 == min2
                   || (min1 && min2
                       && ((TREE_CODE (min1) == PLACEHOLDER_EXPR
                            && TREE_CODE (min2) == PLACEHOLDER_EXPR)
                           || operand_equal_p (min1, min2, 0))))
                  && (max1 == max2
                      || (max1 && max2
                          && ((TREE_CODE (max1) == PLACEHOLDER_EXPR
                               && TREE_CODE (max2) == PLACEHOLDER_EXPR)
                              || operand_equal_p (max1, max2, 0)))))
                return true;
              else
                return false;
            }
        }

    case METHOD_TYPE:
    case FUNCTION_TYPE:
      /* Function types are the same if the return type and arguments types
         are the same.  */
      if (!gimple_canonical_types_compatible_p (TREE_TYPE (t1), TREE_TYPE (t2)))
        return false;

      if (!comp_type_attributes (t1, t2))
        return false;

      if (TYPE_ARG_TYPES (t1) == TYPE_ARG_TYPES (t2))
        return true;
      else
        {
          tree parms1, parms2;

          for (parms1 = TYPE_ARG_TYPES (t1), parms2 = TYPE_ARG_TYPES (t2);
               parms1 && parms2;
               parms1 = TREE_CHAIN (parms1), parms2 = TREE_CHAIN (parms2))
            {
              if (!gimple_canonical_types_compatible_p
                     (TREE_VALUE (parms1), TREE_VALUE (parms2)))
                return false;
            }

          if (parms1 || parms2)
            return false;

          return true;
        }

    case RECORD_TYPE:
    case UNION_TYPE:
    case QUAL_UNION_TYPE:
      {
        tree f1, f2;

        /* For aggregate types, all the fields must be the same.  */
        for (f1 = TYPE_FIELDS (t1), f2 = TYPE_FIELDS (t2);
             f1 || f2;
             f1 = TREE_CHAIN (f1), f2 = TREE_CHAIN (f2))
          {
            /* Skip non-fields.  */
            while (f1 && TREE_CODE (f1) != FIELD_DECL)
              f1 = TREE_CHAIN (f1);
            while (f2 && TREE_CODE (f2) != FIELD_DECL)
              f2 = TREE_CHAIN (f2);
            if (!f1 || !f2)
              break;
            /* The fields must have the same name, offset and type.  */
            if (DECL_NONADDRESSABLE_P (f1) != DECL_NONADDRESSABLE_P (f2)
                || !gimple_compare_field_offset (f1, f2)
                || !gimple_canonical_types_compatible_p
                      (TREE_TYPE (f1), TREE_TYPE (f2)))
              return false;
          }

        /* If one aggregate has more fields than the other, they
           are not the same.  */
        if (f1 || f2)
          return false;

        return true;
      }

    default:
      gcc_unreachable ();
    }
}


/* Returns nonzero if P1 and P2 are equal.  */

static int
gimple_canonical_type_eq (const void *p1, const void *p2)
{
  const_tree t1 = (const_tree) p1;
  const_tree t2 = (const_tree) p2;
  return gimple_canonical_types_compatible_p (CONST_CAST_TREE (t1),
                                              CONST_CAST_TREE (t2));
}

/* Register type T in the global type table gimple_types.
   If another type T', compatible with T, already existed in
   gimple_types then return T', otherwise return T.  This is used by
   LTO to merge identical types read from different TUs.

   ???  This merging does not exactly match how the tree.c middle-end
   functions will assign TYPE_CANONICAL when new types are created
   during optimization (which at least happens for pointer and array
   types).  */

tree
gimple_register_canonical_type (tree t)
{
  void **slot;

  gcc_assert (TYPE_P (t));

  if (TYPE_CANONICAL (t))
    return TYPE_CANONICAL (t);

  if (gimple_canonical_types == NULL)
    gimple_canonical_types = htab_create_ggc (16381, gimple_canonical_type_hash,
                                              gimple_canonical_type_eq, 0);

  slot = htab_find_slot (gimple_canonical_types, t, INSERT);
  if (*slot
      && *(tree *)slot != t)
    {
      tree new_type = (tree) *((tree *) slot);

      TYPE_CANONICAL (t) = new_type;
      t = new_type;
    }
  else
    {
      TYPE_CANONICAL (t) = t;
      *slot = (void *) t;
    }

  return t;
}


/* Show statistics on references to the global type table gimple_types.  */

void
print_gimple_types_stats (const char *pfx)
{
  if (gimple_canonical_types)
    fprintf (stderr, "[%s] GIMPLE canonical type table: size %ld, "
             "%ld elements, %ld searches, %ld collisions (ratio: %f)\n", pfx,
             (long) htab_size (gimple_canonical_types),
             (long) htab_elements (gimple_canonical_types),
             (long) gimple_canonical_types->searches,
             (long) gimple_canonical_types->collisions,
             htab_collisions (gimple_canonical_types));
  else
    fprintf (stderr, "[%s] GIMPLE canonical type table is empty\n", pfx);
  if (canonical_type_hash_cache)
    fprintf (stderr, "[%s] GIMPLE canonical type hash table: size %ld, "
             "%ld elements, %ld searches, %ld collisions (ratio: %f)\n", pfx,
             (long) htab_size (canonical_type_hash_cache),
             (long) htab_elements (canonical_type_hash_cache),
             (long) canonical_type_hash_cache->searches,
             (long) canonical_type_hash_cache->collisions,
             htab_collisions (canonical_type_hash_cache));
  else
    fprintf (stderr, "[%s] GIMPLE canonical type hash table is empty\n", pfx);
}

/* Free the gimple type hashtables used for LTO type merging.  */

void
free_gimple_type_tables (void)
{
  if (gimple_canonical_types)
    {
      htab_delete (gimple_canonical_types);
      gimple_canonical_types = NULL;
    }
  if (canonical_type_hash_cache)
    {
      htab_delete (canonical_type_hash_cache);
      canonical_type_hash_cache = NULL;
    }
}


/* Return a type the same as TYPE except unsigned or
   signed according to UNSIGNEDP.  */

static tree
gimple_signed_or_unsigned_type (bool unsignedp, tree type)
{
  tree type1;

  type1 = TYPE_MAIN_VARIANT (type);
  if (type1 == signed_char_type_node
      || type1 == char_type_node
      || type1 == unsigned_char_type_node)
    return unsignedp ? unsigned_char_type_node : signed_char_type_node;
  if (type1 == integer_type_node || type1 == unsigned_type_node)
    return unsignedp ? unsigned_type_node : integer_type_node;
  if (type1 == short_integer_type_node || type1 == short_unsigned_type_node)
    return unsignedp ? short_unsigned_type_node : short_integer_type_node;
  if (type1 == long_integer_type_node || type1 == long_unsigned_type_node)
    return unsignedp ? long_unsigned_type_node : long_integer_type_node;
  if (type1 == long_long_integer_type_node
      || type1 == long_long_unsigned_type_node)
    return unsignedp
           ? long_long_unsigned_type_node
           : long_long_integer_type_node;
  if (int128_integer_type_node && (type1 == int128_integer_type_node || type1 == int128_unsigned_type_node))
    return unsignedp
           ? int128_unsigned_type_node
           : int128_integer_type_node;
#if HOST_BITS_PER_WIDE_INT >= 64
  if (type1 == intTI_type_node || type1 == unsigned_intTI_type_node)
    return unsignedp ? unsigned_intTI_type_node : intTI_type_node;
#endif
  if (type1 == intDI_type_node || type1 == unsigned_intDI_type_node)
    return unsignedp ? unsigned_intDI_type_node : intDI_type_node;
  if (type1 == intSI_type_node || type1 == unsigned_intSI_type_node)
    return unsignedp ? unsigned_intSI_type_node : intSI_type_node;
  if (type1 == intHI_type_node || type1 == unsigned_intHI_type_node)
    return unsignedp ? unsigned_intHI_type_node : intHI_type_node;
  if (type1 == intQI_type_node || type1 == unsigned_intQI_type_node)
    return unsignedp ? unsigned_intQI_type_node : intQI_type_node;

#define GIMPLE_FIXED_TYPES(NAME)            \
  if (type1 == short_ ## NAME ## _type_node \
      || type1 == unsigned_short_ ## NAME ## _type_node) \
    return unsignedp ? unsigned_short_ ## NAME ## _type_node \
                     : short_ ## NAME ## _type_node; \
  if (type1 == NAME ## _type_node \
      || type1 == unsigned_ ## NAME ## _type_node) \
    return unsignedp ? unsigned_ ## NAME ## _type_node \
                     : NAME ## _type_node; \
  if (type1 == long_ ## NAME ## _type_node \
      || type1 == unsigned_long_ ## NAME ## _type_node) \
    return unsignedp ? unsigned_long_ ## NAME ## _type_node \
                     : long_ ## NAME ## _type_node; \
  if (type1 == long_long_ ## NAME ## _type_node \
      || type1 == unsigned_long_long_ ## NAME ## _type_node) \
    return unsignedp ? unsigned_long_long_ ## NAME ## _type_node \
                     : long_long_ ## NAME ## _type_node;

#define GIMPLE_FIXED_MODE_TYPES(NAME) \
  if (type1 == NAME ## _type_node \
      || type1 == u ## NAME ## _type_node) \
    return unsignedp ? u ## NAME ## _type_node \
                     : NAME ## _type_node;

#define GIMPLE_FIXED_TYPES_SAT(NAME) \
  if (type1 == sat_ ## short_ ## NAME ## _type_node \
      || type1 == sat_ ## unsigned_short_ ## NAME ## _type_node) \
    return unsignedp ? sat_ ## unsigned_short_ ## NAME ## _type_node \
                     : sat_ ## short_ ## NAME ## _type_node; \
  if (type1 == sat_ ## NAME ## _type_node \
      || type1 == sat_ ## unsigned_ ## NAME ## _type_node) \
    return unsignedp ? sat_ ## unsigned_ ## NAME ## _type_node \
                     : sat_ ## NAME ## _type_node; \
  if (type1 == sat_ ## long_ ## NAME ## _type_node \
      || type1 == sat_ ## unsigned_long_ ## NAME ## _type_node) \
    return unsignedp ? sat_ ## unsigned_long_ ## NAME ## _type_node \
                     : sat_ ## long_ ## NAME ## _type_node; \
  if (type1 == sat_ ## long_long_ ## NAME ## _type_node \
      || type1 == sat_ ## unsigned_long_long_ ## NAME ## _type_node) \
    return unsignedp ? sat_ ## unsigned_long_long_ ## NAME ## _type_node \
                     : sat_ ## long_long_ ## NAME ## _type_node;

#define GIMPLE_FIXED_MODE_TYPES_SAT(NAME)       \
  if (type1 == sat_ ## NAME ## _type_node \
      || type1 == sat_ ## u ## NAME ## _type_node) \
    return unsignedp ? sat_ ## u ## NAME ## _type_node \
                     : sat_ ## NAME ## _type_node;

  GIMPLE_FIXED_TYPES (fract);
  GIMPLE_FIXED_TYPES_SAT (fract);
  GIMPLE_FIXED_TYPES (accum);
  GIMPLE_FIXED_TYPES_SAT (accum);

  GIMPLE_FIXED_MODE_TYPES (qq);
  GIMPLE_FIXED_MODE_TYPES (hq);
  GIMPLE_FIXED_MODE_TYPES (sq);
  GIMPLE_FIXED_MODE_TYPES (dq);
  GIMPLE_FIXED_MODE_TYPES (tq);
  GIMPLE_FIXED_MODE_TYPES_SAT (qq);
  GIMPLE_FIXED_MODE_TYPES_SAT (hq);
  GIMPLE_FIXED_MODE_TYPES_SAT (sq);
  GIMPLE_FIXED_MODE_TYPES_SAT (dq);
  GIMPLE_FIXED_MODE_TYPES_SAT (tq);
  GIMPLE_FIXED_MODE_TYPES (ha);
  GIMPLE_FIXED_MODE_TYPES (sa);
  GIMPLE_FIXED_MODE_TYPES (da);
  GIMPLE_FIXED_MODE_TYPES (ta);
  GIMPLE_FIXED_MODE_TYPES_SAT (ha);
  GIMPLE_FIXED_MODE_TYPES_SAT (sa);
  GIMPLE_FIXED_MODE_TYPES_SAT (da);
  GIMPLE_FIXED_MODE_TYPES_SAT (ta);

  /* For ENUMERAL_TYPEs in C++, must check the mode of the types, not
     the precision; they have precision set to match their range, but
     may use a wider mode to match an ABI.  If we change modes, we may
     wind up with bad conversions.  For INTEGER_TYPEs in C, must check
     the precision as well, so as to yield correct results for
     bit-field types.  C++ does not have these separate bit-field
     types, and producing a signed or unsigned variant of an
     ENUMERAL_TYPE may cause other problems as well.  */
  if (!INTEGRAL_TYPE_P (type)
      || TYPE_UNSIGNED (type) == unsignedp)
    return type;

#define TYPE_OK(node)                                                       \
  (TYPE_MODE (type) == TYPE_MODE (node)                                     \
   && TYPE_PRECISION (type) == TYPE_PRECISION (node))
  if (TYPE_OK (signed_char_type_node))
    return unsignedp ? unsigned_char_type_node : signed_char_type_node;
  if (TYPE_OK (integer_type_node))
    return unsignedp ? unsigned_type_node : integer_type_node;
  if (TYPE_OK (short_integer_type_node))
    return unsignedp ? short_unsigned_type_node : short_integer_type_node;
  if (TYPE_OK (long_integer_type_node))
    return unsignedp ? long_unsigned_type_node : long_integer_type_node;
  if (TYPE_OK (long_long_integer_type_node))
    return (unsignedp
            ? long_long_unsigned_type_node
            : long_long_integer_type_node);
  if (int128_integer_type_node && TYPE_OK (int128_integer_type_node))
    return (unsignedp
            ? int128_unsigned_type_node
            : int128_integer_type_node);

#if HOST_BITS_PER_WIDE_INT >= 64
  if (TYPE_OK (intTI_type_node))
    return unsignedp ? unsigned_intTI_type_node : intTI_type_node;
#endif
  if (TYPE_OK (intDI_type_node))
    return unsignedp ? unsigned_intDI_type_node : intDI_type_node;
  if (TYPE_OK (intSI_type_node))
    return unsignedp ? unsigned_intSI_type_node : intSI_type_node;
  if (TYPE_OK (intHI_type_node))
    return unsignedp ? unsigned_intHI_type_node : intHI_type_node;
  if (TYPE_OK (intQI_type_node))
    return unsignedp ? unsigned_intQI_type_node : intQI_type_node;

#undef GIMPLE_FIXED_TYPES
#undef GIMPLE_FIXED_MODE_TYPES
#undef GIMPLE_FIXED_TYPES_SAT
#undef GIMPLE_FIXED_MODE_TYPES_SAT
#undef TYPE_OK

  return build_nonstandard_integer_type (TYPE_PRECISION (type), unsignedp);
}


/* Return an unsigned type the same as TYPE in other respects.  */

tree
gimple_unsigned_type (tree type)
{
  return gimple_signed_or_unsigned_type (true, type);
}


/* Return a signed type the same as TYPE in other respects.  */

tree
gimple_signed_type (tree type)
{
  return gimple_signed_or_unsigned_type (false, type);
}


/* Return the typed-based alias set for T, which may be an expression
   or a type.  Return -1 if we don't do anything special.  */

alias_set_type
gimple_get_alias_set (tree t)
{
  tree u;

  /* Permit type-punning when accessing a union, provided the access
     is directly through the union.  For example, this code does not
     permit taking the address of a union member and then storing
     through it.  Even the type-punning allowed here is a GCC
     extension, albeit a common and useful one; the C standard says
     that such accesses have implementation-defined behavior.  */
  for (u = t;
       TREE_CODE (u) == COMPONENT_REF || TREE_CODE (u) == ARRAY_REF;
       u = TREE_OPERAND (u, 0))
    if (TREE_CODE (u) == COMPONENT_REF
        && TREE_CODE (TREE_TYPE (TREE_OPERAND (u, 0))) == UNION_TYPE)
      return 0;

  /* That's all the expressions we handle specially.  */
  if (!TYPE_P (t))
    return -1;

  /* For convenience, follow the C standard when dealing with
     character types.  Any object may be accessed via an lvalue that
     has character type.  */
  if (t == char_type_node
      || t == signed_char_type_node
      || t == unsigned_char_type_node)
    return 0;

  /* Allow aliasing between signed and unsigned variants of the same
     type.  We treat the signed variant as canonical.  */
  if (TREE_CODE (t) == INTEGER_TYPE && TYPE_UNSIGNED (t))
    {
      tree t1 = gimple_signed_type (t);

      /* t1 == t can happen for boolean nodes which are always unsigned.  */
      if (t1 != t)
        return get_alias_set (t1);
    }

  return -1;
}


/* From a tree operand OP return the base of a load or store operation
   or NULL_TREE if OP is not a load or a store.  */

static tree
get_base_loadstore (tree op)
{
  while (handled_component_p (op))
    op = TREE_OPERAND (op, 0);
  if (DECL_P (op)
      || INDIRECT_REF_P (op)
      || TREE_CODE (op) == MEM_REF
      || TREE_CODE (op) == TARGET_MEM_REF)
    return op;
  return NULL_TREE;
}

/* For the statement STMT call the callbacks VISIT_LOAD, VISIT_STORE and
   VISIT_ADDR if non-NULL on loads, store and address-taken operands
   passing the STMT, the base of the operand and DATA to it.  The base
   will be either a decl, an indirect reference (including TARGET_MEM_REF)
   or the argument of an address expression.
   Returns the results of these callbacks or'ed.  */

bool
walk_stmt_load_store_addr_ops (gimple stmt, void *data,
                               bool (*visit_load)(gimple, tree, void *),
                               bool (*visit_store)(gimple, tree, void *),
                               bool (*visit_addr)(gimple, tree, void *))
{
  bool ret = false;
  unsigned i;
  if (gimple_assign_single_p (stmt))
    {
      tree lhs, rhs;
      if (visit_store)
        {
          lhs = get_base_loadstore (gimple_assign_lhs (stmt));
          if (lhs)
            ret |= visit_store (stmt, lhs, data);
        }
      rhs = gimple_assign_rhs1 (stmt);
      while (handled_component_p (rhs))
        rhs = TREE_OPERAND (rhs, 0);
      if (visit_addr)
        {
          if (TREE_CODE (rhs) == ADDR_EXPR)
            ret |= visit_addr (stmt, TREE_OPERAND (rhs, 0), data);
          else if (TREE_CODE (rhs) == TARGET_MEM_REF
                   && TREE_CODE (TMR_BASE (rhs)) == ADDR_EXPR)
            ret |= visit_addr (stmt, TREE_OPERAND (TMR_BASE (rhs), 0), data);
          else if (TREE_CODE (rhs) == OBJ_TYPE_REF
                   && TREE_CODE (OBJ_TYPE_REF_OBJECT (rhs)) == ADDR_EXPR)
            ret |= visit_addr (stmt, TREE_OPERAND (OBJ_TYPE_REF_OBJECT (rhs),
                                                   0), data);
          else if (TREE_CODE (rhs) == CONSTRUCTOR)
            {
              unsigned int ix;
              tree val;

              FOR_EACH_CONSTRUCTOR_VALUE (CONSTRUCTOR_ELTS (rhs), ix, val)
                if (TREE_CODE (val) == ADDR_EXPR)
                  ret |= visit_addr (stmt, TREE_OPERAND (val, 0), data);
                else if (TREE_CODE (val) == OBJ_TYPE_REF
                         && TREE_CODE (OBJ_TYPE_REF_OBJECT (val)) == ADDR_EXPR)
                  ret |= visit_addr (stmt,
                                     TREE_OPERAND (OBJ_TYPE_REF_OBJECT (val),
                                                   0), data);
            }
          lhs = gimple_assign_lhs (stmt);
          if (TREE_CODE (lhs) == TARGET_MEM_REF
              && TREE_CODE (TMR_BASE (lhs)) == ADDR_EXPR)
            ret |= visit_addr (stmt, TREE_OPERAND (TMR_BASE (lhs), 0), data);
        }
      if (visit_load)
        {
          rhs = get_base_loadstore (rhs);
          if (rhs)
            ret |= visit_load (stmt, rhs, data);
        }
    }
  else if (visit_addr
           && (is_gimple_assign (stmt)
               || gimple_code (stmt) == GIMPLE_COND))
    {
      for (i = 0; i < gimple_num_ops (stmt); ++i)
        {
          tree op = gimple_op (stmt, i);
          if (op == NULL_TREE)
            ;
          else if (TREE_CODE (op) == ADDR_EXPR)
            ret |= visit_addr (stmt, TREE_OPERAND (op, 0), data);
          /* COND_EXPR and VCOND_EXPR rhs1 argument is a comparison
             tree with two operands.  */
          else if (i == 1 && COMPARISON_CLASS_P (op))
            {
              if (TREE_CODE (TREE_OPERAND (op, 0)) == ADDR_EXPR)
                ret |= visit_addr (stmt, TREE_OPERAND (TREE_OPERAND (op, 0),
                                                       0), data);
              if (TREE_CODE (TREE_OPERAND (op, 1)) == ADDR_EXPR)
                ret |= visit_addr (stmt, TREE_OPERAND (TREE_OPERAND (op, 1),
                                                       0), data);
            }
        }
    }
  else if (is_gimple_call (stmt))
    {
      if (visit_store)
        {
          tree lhs = gimple_call_lhs (stmt);
          if (lhs)
            {
              lhs = get_base_loadstore (lhs);
              if (lhs)
                ret |= visit_store (stmt, lhs, data);
            }
        }
      if (visit_load || visit_addr)
        for (i = 0; i < gimple_call_num_args (stmt); ++i)
          {
            tree rhs = gimple_call_arg (stmt, i);
            if (visit_addr
                && TREE_CODE (rhs) == ADDR_EXPR)
              ret |= visit_addr (stmt, TREE_OPERAND (rhs, 0), data);
            else if (visit_load)
              {
                rhs = get_base_loadstore (rhs);
                if (rhs)
                  ret |= visit_load (stmt, rhs, data);
              }
          }
      if (visit_addr
          && gimple_call_chain (stmt)
          && TREE_CODE (gimple_call_chain (stmt)) == ADDR_EXPR)
        ret |= visit_addr (stmt, TREE_OPERAND (gimple_call_chain (stmt), 0),
                           data);
      if (visit_addr
          && gimple_call_return_slot_opt_p (stmt)
          && gimple_call_lhs (stmt) != NULL_TREE
          && TREE_ADDRESSABLE (TREE_TYPE (gimple_call_lhs (stmt))))
        ret |= visit_addr (stmt, gimple_call_lhs (stmt), data);
    }
  else if (gimple_code (stmt) == GIMPLE_ASM)
    {
      unsigned noutputs;
      const char *constraint;
      const char **oconstraints;
      bool allows_mem, allows_reg, is_inout;
      noutputs = gimple_asm_noutputs (stmt);
      oconstraints = XALLOCAVEC (const char *, noutputs);
      if (visit_store || visit_addr)
        for (i = 0; i < gimple_asm_noutputs (stmt); ++i)
          {
            tree link = gimple_asm_output_op (stmt, i);
            tree op = get_base_loadstore (TREE_VALUE (link));
            if (op && visit_store)
              ret |= visit_store (stmt, op, data);
            if (visit_addr)
              {
                constraint = TREE_STRING_POINTER
                    (TREE_VALUE (TREE_PURPOSE (link)));
                oconstraints[i] = constraint;
                parse_output_constraint (&constraint, i, 0, 0, &allows_mem,
                                         &allows_reg, &is_inout);
                if (op && !allows_reg && allows_mem)
                  ret |= visit_addr (stmt, op, data);
              }
          }
      if (visit_load || visit_addr)
        for (i = 0; i < gimple_asm_ninputs (stmt); ++i)
          {
            tree link = gimple_asm_input_op (stmt, i);
            tree op = TREE_VALUE (link);
            if (visit_addr
                && TREE_CODE (op) == ADDR_EXPR)
              ret |= visit_addr (stmt, TREE_OPERAND (op, 0), data);
            else if (visit_load || visit_addr)
              {
                op = get_base_loadstore (op);
                if (op)
                  {
                    if (visit_load)
                      ret |= visit_load (stmt, op, data);
                    if (visit_addr)
                      {
                        constraint = TREE_STRING_POINTER
                            (TREE_VALUE (TREE_PURPOSE (link)));
                        parse_input_constraint (&constraint, 0, 0, noutputs,
                                                0, oconstraints,
                                                &allows_mem, &allows_reg);
                        if (!allows_reg && allows_mem)
                          ret |= visit_addr (stmt, op, data);
                      }
                  }
              }
          }
    }
  else if (gimple_code (stmt) == GIMPLE_RETURN)
    {
      tree op = gimple_return_retval (stmt);
      if (op)
        {
          if (visit_addr
              && TREE_CODE (op) == ADDR_EXPR)
            ret |= visit_addr (stmt, TREE_OPERAND (op, 0), data);
          else if (visit_load)
            {
              op = get_base_loadstore (op);
              if (op)
                ret |= visit_load (stmt, op, data);
            }
        }
    }
  else if (visit_addr
           && gimple_code (stmt) == GIMPLE_PHI)
    {
      for (i = 0; i < gimple_phi_num_args (stmt); ++i)
        {
          tree op = PHI_ARG_DEF (stmt, i);
          if (TREE_CODE (op) == ADDR_EXPR)
            ret |= visit_addr (stmt, TREE_OPERAND (op, 0), data);
        }
    }
  else if (visit_addr
           && gimple_code (stmt) == GIMPLE_GOTO)
    {
      tree op = gimple_goto_dest (stmt);
      if (TREE_CODE (op) == ADDR_EXPR)
        ret |= visit_addr (stmt, TREE_OPERAND (op, 0), data);
    }

  return ret;
}

/* Like walk_stmt_load_store_addr_ops but with NULL visit_addr.  IPA-CP
   should make a faster clone for this case.  */

bool
walk_stmt_load_store_ops (gimple stmt, void *data,
                          bool (*visit_load)(gimple, tree, void *),
                          bool (*visit_store)(gimple, tree, void *))
{
  return walk_stmt_load_store_addr_ops (stmt, data,
                                        visit_load, visit_store, NULL);
}

/* Helper for gimple_ior_addresses_taken_1.  */

static bool
gimple_ior_addresses_taken_1 (gimple stmt ATTRIBUTE_UNUSED,
                              tree addr, void *data)
{
  bitmap addresses_taken = (bitmap)data;
  addr = get_base_address (addr);
  if (addr
      && DECL_P (addr))
    {
      bitmap_set_bit (addresses_taken, DECL_UID (addr));
      return true;
    }
  return false;
}

/* Set the bit for the uid of all decls that have their address taken
   in STMT in the ADDRESSES_TAKEN bitmap.  Returns true if there
   were any in this stmt.  */

bool
gimple_ior_addresses_taken (bitmap addresses_taken, gimple stmt)
{
  return walk_stmt_load_store_addr_ops (stmt, addresses_taken, NULL, NULL,
                                        gimple_ior_addresses_taken_1);
}


/* Return a printable name for symbol DECL.  */

const char *
gimple_decl_printable_name (tree decl, int verbosity)
{
  if (!DECL_NAME (decl))
    return NULL;

  if (DECL_ASSEMBLER_NAME_SET_P (decl))
    {
      const char *str, *mangled_str;
      int dmgl_opts = DMGL_NO_OPTS;

      if (verbosity >= 2)
        {
          dmgl_opts = DMGL_VERBOSE
                      | DMGL_ANSI
                      | DMGL_GNU_V3
                      | DMGL_RET_POSTFIX;
          if (TREE_CODE (decl) == FUNCTION_DECL)
            dmgl_opts |= DMGL_PARAMS;
        }

      mangled_str = IDENTIFIER_POINTER (DECL_ASSEMBLER_NAME (decl));
      str = cplus_demangle_v3 (mangled_str, dmgl_opts);
      return (str) ? str : mangled_str;
    }

  return IDENTIFIER_POINTER (DECL_NAME (decl));
}

/* Return TRUE iff stmt is a call to a built-in function.  */

bool
is_gimple_builtin_call (gimple stmt)
{
  tree callee;

  if (is_gimple_call (stmt)
      && (callee = gimple_call_fndecl (stmt))
      && is_builtin_fn (callee)
      && DECL_BUILT_IN_CLASS (callee) == BUILT_IN_NORMAL)
    return true;

  return false;
}

/* Return true when STMTs arguments match those of FNDECL.  */

static bool
validate_call (gimple stmt, tree fndecl)
{
  tree targs = TYPE_ARG_TYPES (TREE_TYPE (fndecl));
  unsigned nargs = gimple_call_num_args (stmt);
  for (unsigned i = 0; i < nargs; ++i)
    {
      /* Variadic args follow.  */
      if (!targs)
        return true;
      tree arg = gimple_call_arg (stmt, i);
      if (INTEGRAL_TYPE_P (TREE_TYPE (arg))
          && INTEGRAL_TYPE_P (TREE_VALUE (targs)))
        ;
      else if (POINTER_TYPE_P (TREE_TYPE (arg))
               && POINTER_TYPE_P (TREE_VALUE (targs)))
        ;
      else if (TREE_CODE (TREE_TYPE (arg))
               != TREE_CODE (TREE_VALUE (targs)))
        return false;
      targs = TREE_CHAIN (targs);
    }
  if (targs && !VOID_TYPE_P (TREE_VALUE (targs)))
    return false;
  return true;
}

/* Return true when STMT is builtins call to CLASS.  */

bool
gimple_call_builtin_p (gimple stmt, enum built_in_class klass)
{
  tree fndecl;
  if (is_gimple_call (stmt)
      && (fndecl = gimple_call_fndecl (stmt)) != NULL_TREE
      && DECL_BUILT_IN_CLASS (fndecl) == klass)
    return validate_call (stmt, fndecl);
  return false;
}

/* Return true when STMT is builtins call to CODE of CLASS.  */

bool
gimple_call_builtin_p (gimple stmt, enum built_in_function code)
{
  tree fndecl;
  if (is_gimple_call (stmt)
      && (fndecl = gimple_call_fndecl (stmt)) != NULL_TREE
      && DECL_BUILT_IN_CLASS (fndecl) == BUILT_IN_NORMAL 
      && DECL_FUNCTION_CODE (fndecl) == code)
    return validate_call (stmt, fndecl);
  return false;
}

/* Return true if STMT clobbers memory.  STMT is required to be a
   GIMPLE_ASM.  */

bool
gimple_asm_clobbers_memory_p (const_gimple stmt)
{
  unsigned i;

  for (i = 0; i < gimple_asm_nclobbers (stmt); i++)
    {
      tree op = gimple_asm_clobber_op (stmt, i);
      if (strcmp (TREE_STRING_POINTER (TREE_VALUE (op)), "memory") == 0)
        return true;
    }

  return false;
}


/* Return true if the conversion from INNER_TYPE to OUTER_TYPE is a
   useless type conversion, otherwise return false.

   This function implicitly defines the middle-end type system.  With
   the notion of 'a < b' meaning that useless_type_conversion_p (a, b)
   holds and 'a > b' meaning that useless_type_conversion_p (b, a) holds,
   the following invariants shall be fulfilled:

     1) useless_type_conversion_p is transitive.
        If a < b and b < c then a < c.

     2) useless_type_conversion_p is not symmetric.
        From a < b does not follow a > b.

     3) Types define the available set of operations applicable to values.
        A type conversion is useless if the operations for the target type
        is a subset of the operations for the source type.  For example
        casts to void* are useless, casts from void* are not (void* can't
        be dereferenced or offsetted, but copied, hence its set of operations
        is a strict subset of that of all other data pointer types).  Casts
        to const T* are useless (can't be written to), casts from const T*
        to T* are not.  */

bool
useless_type_conversion_p (tree outer_type, tree inner_type)
{
  /* Do the following before stripping toplevel qualifiers.  */
  if (POINTER_TYPE_P (inner_type)
      && POINTER_TYPE_P (outer_type))
    {
      /* Do not lose casts between pointers to different address spaces.  */
      if (TYPE_ADDR_SPACE (TREE_TYPE (outer_type))
          != TYPE_ADDR_SPACE (TREE_TYPE (inner_type)))
        return false;
    }

  /* From now on qualifiers on value types do not matter.  */
  inner_type = TYPE_MAIN_VARIANT (inner_type);
  outer_type = TYPE_MAIN_VARIANT (outer_type);

  if (inner_type == outer_type)
    return true;

  /* If we know the canonical types, compare them.  */
  if (TYPE_CANONICAL (inner_type)
      && TYPE_CANONICAL (inner_type) == TYPE_CANONICAL (outer_type))
    return true;

  /* Changes in machine mode are never useless conversions unless we
     deal with aggregate types in which case we defer to later checks.  */
  if (TYPE_MODE (inner_type) != TYPE_MODE (outer_type)
      && !AGGREGATE_TYPE_P (inner_type))
    return false;

  /* If both the inner and outer types are integral types, then the
     conversion is not necessary if they have the same mode and
     signedness and precision, and both or neither are boolean.  */
  if (INTEGRAL_TYPE_P (inner_type)
      && INTEGRAL_TYPE_P (outer_type))
    {
      /* Preserve changes in signedness or precision.  */
      if (TYPE_UNSIGNED (inner_type) != TYPE_UNSIGNED (outer_type)
          || TYPE_PRECISION (inner_type) != TYPE_PRECISION (outer_type))
        return false;

      /* Preserve conversions to/from BOOLEAN_TYPE if types are not
         of precision one.  */
      if (((TREE_CODE (inner_type) == BOOLEAN_TYPE)
           != (TREE_CODE (outer_type) == BOOLEAN_TYPE))
          && TYPE_PRECISION (outer_type) != 1)
        return false;

      /* We don't need to preserve changes in the types minimum or
         maximum value in general as these do not generate code
         unless the types precisions are different.  */
      return true;
    }

  /* Scalar floating point types with the same mode are compatible.  */
  else if (SCALAR_FLOAT_TYPE_P (inner_type)
           && SCALAR_FLOAT_TYPE_P (outer_type))
    return true;

  /* Fixed point types with the same mode are compatible.  */
  else if (FIXED_POINT_TYPE_P (inner_type)
           && FIXED_POINT_TYPE_P (outer_type))
    return true;

  /* We need to take special care recursing to pointed-to types.  */
  else if (POINTER_TYPE_P (inner_type)
           && POINTER_TYPE_P (outer_type))
    {
      /* Do not lose casts to function pointer types.  */
      if ((TREE_CODE (TREE_TYPE (outer_type)) == FUNCTION_TYPE
           || TREE_CODE (TREE_TYPE (outer_type)) == METHOD_TYPE)
          && !(TREE_CODE (TREE_TYPE (inner_type)) == FUNCTION_TYPE
               || TREE_CODE (TREE_TYPE (inner_type)) == METHOD_TYPE))
        return false;

      /* We do not care for const qualification of the pointed-to types
         as const qualification has no semantic value to the middle-end.  */

      /* Otherwise pointers/references are equivalent.  */
      return true;
    }

  /* Recurse for complex types.  */
  else if (TREE_CODE (inner_type) == COMPLEX_TYPE
           && TREE_CODE (outer_type) == COMPLEX_TYPE)
    return useless_type_conversion_p (TREE_TYPE (outer_type),
                                      TREE_TYPE (inner_type));

  /* Recurse for vector types with the same number of subparts.  */
  else if (TREE_CODE (inner_type) == VECTOR_TYPE
           && TREE_CODE (outer_type) == VECTOR_TYPE
           && TYPE_PRECISION (inner_type) == TYPE_PRECISION (outer_type))
    return useless_type_conversion_p (TREE_TYPE (outer_type),
                                      TREE_TYPE (inner_type));

  else if (TREE_CODE (inner_type) == ARRAY_TYPE
           && TREE_CODE (outer_type) == ARRAY_TYPE)
    {
      /* Preserve string attributes.  */
      if (TYPE_STRING_FLAG (inner_type) != TYPE_STRING_FLAG (outer_type))
        return false;

      /* Conversions from array types with unknown extent to
         array types with known extent are not useless.  */
      if (!TYPE_DOMAIN (inner_type)
          && TYPE_DOMAIN (outer_type))
        return false;

      /* Nor are conversions from array types with non-constant size to
         array types with constant size or to different size.  */
      if (TYPE_SIZE (outer_type)
          && TREE_CODE (TYPE_SIZE (outer_type)) == INTEGER_CST
          && (!TYPE_SIZE (inner_type)
              || TREE_CODE (TYPE_SIZE (inner_type)) != INTEGER_CST
              || !tree_int_cst_equal (TYPE_SIZE (outer_type),
                                      TYPE_SIZE (inner_type))))
        return false;

      /* Check conversions between arrays with partially known extents.
         If the array min/max values are constant they have to match.
         Otherwise allow conversions to unknown and variable extents.
         In particular this declares conversions that may change the
         mode to BLKmode as useless.  */
      if (TYPE_DOMAIN (inner_type)
          && TYPE_DOMAIN (outer_type)
          && TYPE_DOMAIN (inner_type) != TYPE_DOMAIN (outer_type))
        {
          tree inner_min = TYPE_MIN_VALUE (TYPE_DOMAIN (inner_type));
          tree outer_min = TYPE_MIN_VALUE (TYPE_DOMAIN (outer_type));
          tree inner_max = TYPE_MAX_VALUE (TYPE_DOMAIN (inner_type));
          tree outer_max = TYPE_MAX_VALUE (TYPE_DOMAIN (outer_type));

          /* After gimplification a variable min/max value carries no
             additional information compared to a NULL value.  All that
             matters has been lowered to be part of the IL.  */
          if (inner_min && TREE_CODE (inner_min) != INTEGER_CST)
            inner_min = NULL_TREE;
          if (outer_min && TREE_CODE (outer_min) != INTEGER_CST)
            outer_min = NULL_TREE;
          if (inner_max && TREE_CODE (inner_max) != INTEGER_CST)
            inner_max = NULL_TREE;
          if (outer_max && TREE_CODE (outer_max) != INTEGER_CST)
            outer_max = NULL_TREE;

          /* Conversions NULL / variable <- cst are useless, but not
             the other way around.  */
          if (outer_min
              && (!inner_min
                  || !tree_int_cst_equal (inner_min, outer_min)))
            return false;
          if (outer_max
              && (!inner_max
                  || !tree_int_cst_equal (inner_max, outer_max)))
            return false;
        }

      /* Recurse on the element check.  */
      return useless_type_conversion_p (TREE_TYPE (outer_type),
                                        TREE_TYPE (inner_type));
    }

  else if ((TREE_CODE (inner_type) == FUNCTION_TYPE
            || TREE_CODE (inner_type) == METHOD_TYPE)
           && TREE_CODE (inner_type) == TREE_CODE (outer_type))
    {
      tree outer_parm, inner_parm;

      /* If the return types are not compatible bail out.  */
      if (!useless_type_conversion_p (TREE_TYPE (outer_type),
                                      TREE_TYPE (inner_type)))
        return false;

      /* Method types should belong to a compatible base class.  */
      if (TREE_CODE (inner_type) == METHOD_TYPE
          && !useless_type_conversion_p (TYPE_METHOD_BASETYPE (outer_type),
                                         TYPE_METHOD_BASETYPE (inner_type)))
        return false;

      /* A conversion to an unprototyped argument list is ok.  */
      if (!prototype_p (outer_type))
        return true;

      /* If the unqualified argument types are compatible the conversion
         is useless.  */
      if (TYPE_ARG_TYPES (outer_type) == TYPE_ARG_TYPES (inner_type))
        return true;

      for (outer_parm = TYPE_ARG_TYPES (outer_type),
           inner_parm = TYPE_ARG_TYPES (inner_type);
           outer_parm && inner_parm;
           outer_parm = TREE_CHAIN (outer_parm),
           inner_parm = TREE_CHAIN (inner_parm))
        if (!useless_type_conversion_p
               (TYPE_MAIN_VARIANT (TREE_VALUE (outer_parm)),
                TYPE_MAIN_VARIANT (TREE_VALUE (inner_parm))))
          return false;

      /* If there is a mismatch in the number of arguments the functions
         are not compatible.  */
      if (outer_parm || inner_parm)
        return false;

      /* Defer to the target if necessary.  */
      if (TYPE_ATTRIBUTES (inner_type) || TYPE_ATTRIBUTES (outer_type))
        return comp_type_attributes (outer_type, inner_type) != 0;

      return true;
    }

  /* For aggregates we rely on TYPE_CANONICAL exclusively and require
     explicit conversions for types involving to be structurally
     compared types.  */
  else if (AGGREGATE_TYPE_P (inner_type)
           && TREE_CODE (inner_type) == TREE_CODE (outer_type))
    return false;

  return false;
}

/* Return true if a conversion from either type of TYPE1 and TYPE2
   to the other is not required.  Otherwise return false.  */

bool
types_compatible_p (tree type1, tree type2)
{
  return (type1 == type2
          || (useless_type_conversion_p (type1, type2)
              && useless_type_conversion_p (type2, type1)));
}


#include "gt-gimple.h"