gimplify.c

		TREE_SIDE_EFFECTS (*p) = 1;
		TREE_TYPE (*p) = void_type_node;
		p = tsi_end_p (i) ? NULL : tsi_stmt_ptr (i);
	      }
	      break;

	    case COMPOUND_EXPR:
	      /* Advance to the last statement.  Set all container types to
		 void.  */
	      for (; TREE_CODE (*p) == COMPOUND_EXPR; p = &TREE_OPERAND (*p, 1))
		{
		  TREE_SIDE_EFFECTS (*p) = 1;
		  TREE_TYPE (*p) = void_type_node;
		}
	      break;

	    case TRANSACTION_EXPR:
	      TREE_SIDE_EFFECTS (*p) = 1;
	      TREE_TYPE (*p) = void_type_node;
	      p = &TRANSACTION_EXPR_BODY (*p);
	      break;

	    default:
	      /* Assume that any tree upon which voidify_wrapper_expr is
		 directly called is a wrapper, and that its body is op0.  */
	      if (p == &wrapper)
		{
		  TREE_SIDE_EFFECTS (*p) = 1;
		  TREE_TYPE (*p) = void_type_node;
		  p = &TREE_OPERAND (*p, 0);
		  break;
		}
	      goto out;
	    }
	}

    out:
      if (p == NULL || IS_EMPTY_STMT (*p))
	temp = NULL_TREE;
      else if (temp)
	{
	  /* The wrapper is on the RHS of an assignment that we're pushing
	     down.  */
	  gcc_assert (TREE_CODE (temp) == INIT_EXPR
		      || TREE_CODE (temp) == MODIFY_EXPR);
	  TREE_OPERAND (temp, 1) = *p;
	  *p = temp;
	}
      else
	{
	  temp = create_tmp_var (type, "retval");
	  *p = build2 (INIT_EXPR, type, temp, *p);
	}

      return temp;
    }

  return NULL_TREE;
}

/* Prepare calls to builtins to SAVE and RESTORE the stack as well as
   a temporary through which they communicate.  */

static void
build_stack_save_restore (gcall **save, gcall **restore)
{
  tree tmp_var;

  *save = gimple_build_call (builtin_decl_implicit (BUILT_IN_STACK_SAVE), 0);
  tmp_var = create_tmp_var (ptr_type_node, "saved_stack");
  gimple_call_set_lhs (*save, tmp_var);

  *restore
    = gimple_build_call (builtin_decl_implicit (BUILT_IN_STACK_RESTORE),
			 1, tmp_var);
}

/* Gimplify a BIND_EXPR.  Just voidify and recurse.  */

static enum gimplify_status
gimplify_bind_expr (tree *expr_p, gimple_seq *pre_p)
{
  tree bind_expr = *expr_p;
  bool old_keep_stack = gimplify_ctxp->keep_stack;
  bool old_save_stack = gimplify_ctxp->save_stack;
  tree t;
  gbind *bind_stmt;
  gimple_seq body, cleanup;
  gcall *stack_save;
  location_t start_locus = 0, end_locus = 0;
  tree ret_clauses = NULL;

  tree temp = voidify_wrapper_expr (bind_expr, NULL);

  /* Mark variables seen in this bind expr.  */
  for (t = BIND_EXPR_VARS (bind_expr); t ; t = DECL_CHAIN (t))
    {
      if (TREE_CODE (t) == VAR_DECL)
	{
	  struct gimplify_omp_ctx *ctx = gimplify_omp_ctxp;

	  /* Mark variable as local.  */
	  if (ctx && ctx->region_type != ORT_NONE && !DECL_EXTERNAL (t)
	      && (! DECL_SEEN_IN_BIND_EXPR_P (t)
		  || splay_tree_lookup (ctx->variables,
					(splay_tree_key) t) == NULL))
	    {
	      if (ctx->region_type == ORT_SIMD
		  && TREE_ADDRESSABLE (t)
		  && !TREE_STATIC (t))
		omp_add_variable (ctx, t, GOVD_PRIVATE | GOVD_SEEN);
	      else
		omp_add_variable (ctx, t, GOVD_LOCAL | GOVD_SEEN);
	    }

	  DECL_SEEN_IN_BIND_EXPR_P (t) = 1;

	  if (DECL_HARD_REGISTER (t) && !is_global_var (t) && cfun)
	    cfun->has_local_explicit_reg_vars = true;
	}

      /* Preliminarily mark non-addressed complex variables as eligible
	 for promotion to gimple registers.  We'll transform their uses
	 as we find them.  */
      if ((TREE_CODE (TREE_TYPE (t)) == COMPLEX_TYPE
	   || TREE_CODE (TREE_TYPE (t)) == VECTOR_TYPE)
	  && !TREE_THIS_VOLATILE (t)
	  && (TREE_CODE (t) == VAR_DECL && !DECL_HARD_REGISTER (t))
	  && !needs_to_live_in_memory (t))
	DECL_GIMPLE_REG_P (t) = 1;
    }

  bind_stmt = gimple_build_bind (BIND_EXPR_VARS (bind_expr), NULL,
				 BIND_EXPR_BLOCK (bind_expr));
  gimple_push_bind_expr (bind_stmt);

  gimplify_ctxp->keep_stack = false;
  gimplify_ctxp->save_stack = false;

  /* Gimplify the body into the GIMPLE_BIND tuple's body.  */
  body = NULL;
  gimplify_stmt (&BIND_EXPR_BODY (bind_expr), &body);
  gimple_bind_set_body (bind_stmt, body);

  /* Source location wise, the cleanup code (stack_restore and clobbers)
     belongs to the end of the block, so propagate what we have.  The
     stack_save operation belongs to the beginning of block, which we can
     infer from the bind_expr directly if the block has no explicit
     assignment.  */
  if (BIND_EXPR_BLOCK (bind_expr))
    {
      end_locus = BLOCK_SOURCE_END_LOCATION (BIND_EXPR_BLOCK (bind_expr));
      start_locus = BLOCK_SOURCE_LOCATION (BIND_EXPR_BLOCK (bind_expr));
    }
  if (start_locus == 0)
    start_locus = EXPR_LOCATION (bind_expr);

  cleanup = NULL;
  stack_save = NULL;

  /* If the code both contains VLAs and calls alloca, then we cannot reclaim
     the stack space allocated to the VLAs.  */
  if (gimplify_ctxp->save_stack && !gimplify_ctxp->keep_stack)
    {
      gcall *stack_restore;

      /* Save stack on entry and restore it on exit.  Add a try_finally
	 block to achieve this.  */
      build_stack_save_restore (&stack_save, &stack_restore);

      gimple_set_location (stack_save, start_locus);
      gimple_set_location (stack_restore, end_locus);

      gimplify_seq_add_stmt (&cleanup, stack_restore);
    }

  /* Add clobbers for all variables that go out of scope.  */
  for (t = BIND_EXPR_VARS (bind_expr); t ; t = DECL_CHAIN (t))
    {
      if (TREE_CODE (t) == VAR_DECL
	  && !is_global_var (t)
	  && DECL_CONTEXT (t) == current_function_decl
	  && !DECL_HARD_REGISTER (t)
	  && !TREE_THIS_VOLATILE (t)
	  && !DECL_HAS_VALUE_EXPR_P (t)
	  /* Only care for variables that have to be in memory.  Others
	     will be rewritten into SSA names, hence moved to the top-level.  */
	  && !is_gimple_reg (t)
	  && flag_stack_reuse != SR_NONE)
	{
	  tree clobber = build_constructor (TREE_TYPE (t), NULL);
	  gimple *clobber_stmt;
	  TREE_THIS_VOLATILE (clobber) = 1;
	  clobber_stmt = gimple_build_assign (t, clobber);
	  gimple_set_location (clobber_stmt, end_locus);
	  gimplify_seq_add_stmt (&cleanup, clobber_stmt);

	  if (flag_openacc && oacc_declare_returns != NULL)
	    {
	      tree *c = oacc_declare_returns->get (t);
	      if (c != NULL)
		{
		  if (ret_clauses)
		    OMP_CLAUSE_CHAIN (*c) = ret_clauses;

		  ret_clauses = *c;

		  oacc_declare_returns->remove (t);

		  if (oacc_declare_returns->elements () == 0)
		    {
		      delete oacc_declare_returns;
		      oacc_declare_returns = NULL;
		    }
		}
	    }
	}
    }

  if (ret_clauses)
    {
      gomp_target *stmt;
      gimple_stmt_iterator si = gsi_start (cleanup);

      stmt = gimple_build_omp_target (NULL, GF_OMP_TARGET_KIND_OACC_DECLARE,
				      ret_clauses);
      gsi_insert_seq_before_without_update (&si, stmt, GSI_NEW_STMT);
    }

  if (cleanup)
    {
      gtry *gs;
      gimple_seq new_body;

      new_body = NULL;
      gs = gimple_build_try (gimple_bind_body (bind_stmt), cleanup,
	  		     GIMPLE_TRY_FINALLY);

      if (stack_save)
	gimplify_seq_add_stmt (&new_body, stack_save);
      gimplify_seq_add_stmt (&new_body, gs);
      gimple_bind_set_body (bind_stmt, new_body);
    }

  /* keep_stack propagates all the way up to the outermost BIND_EXPR.  */
  if (!gimplify_ctxp->keep_stack)
    gimplify_ctxp->keep_stack = old_keep_stack;
  gimplify_ctxp->save_stack = old_save_stack;

  gimple_pop_bind_expr ();

  gimplify_seq_add_stmt (pre_p, bind_stmt);

  if (temp)
    {
      *expr_p = temp;
      return GS_OK;
    }

  *expr_p = NULL_TREE;
  return GS_ALL_DONE;
}

/* Gimplify a RETURN_EXPR.  If the expression to be returned is not a
   GIMPLE value, it is assigned to a new temporary and the statement is
   re-written to return the temporary.

   PRE_P points to the sequence where side effects that must happen before
   STMT should be stored.  */

static enum gimplify_status
gimplify_return_expr (tree stmt, gimple_seq *pre_p)
{
  greturn *ret;
  tree ret_expr = TREE_OPERAND (stmt, 0);
  tree result_decl, result;

  if (ret_expr == error_mark_node)
    return GS_ERROR;

  /* Implicit _Cilk_sync must be inserted right before any return statement 
     if there is a _Cilk_spawn in the function.  If the user has provided a 
     _Cilk_sync, the optimizer should remove this duplicate one.  */
  if (fn_contains_cilk_spawn_p (cfun))
    {
      tree impl_sync = build0 (CILK_SYNC_STMT, void_type_node);
      gimplify_and_add (impl_sync, pre_p);
    }

  if (!ret_expr
      || TREE_CODE (ret_expr) == RESULT_DECL
      || ret_expr == error_mark_node)
    {
      greturn *ret = gimple_build_return (ret_expr);
      gimple_set_no_warning (ret, TREE_NO_WARNING (stmt));
      gimplify_seq_add_stmt (pre_p, ret);
      return GS_ALL_DONE;
    }

  if (VOID_TYPE_P (TREE_TYPE (TREE_TYPE (current_function_decl))))
    result_decl = NULL_TREE;
  else
    {
      result_decl = TREE_OPERAND (ret_expr, 0);

      /* See through a return by reference.  */
      if (TREE_CODE (result_decl) == INDIRECT_REF)
	result_decl = TREE_OPERAND (result_decl, 0);

      gcc_assert ((TREE_CODE (ret_expr) == MODIFY_EXPR
		   || TREE_CODE (ret_expr) == INIT_EXPR)
		  && TREE_CODE (result_decl) == RESULT_DECL);
    }

  /* If aggregate_value_p is true, then we can return the bare RESULT_DECL.
     Recall that aggregate_value_p is FALSE for any aggregate type that is
     returned in registers.  If we're returning values in registers, then
     we don't want to extend the lifetime of the RESULT_DECL, particularly
     across another call.  In addition, for those aggregates for which
     hard_function_value generates a PARALLEL, we'll die during normal
     expansion of structure assignments; there's special code in expand_return
     to handle this case that does not exist in expand_expr.  */
  if (!result_decl)
    result = NULL_TREE;
  else if (aggregate_value_p (result_decl, TREE_TYPE (current_function_decl)))
    {
      if (TREE_CODE (DECL_SIZE (result_decl)) != INTEGER_CST)
	{
	  if (!TYPE_SIZES_GIMPLIFIED (TREE_TYPE (result_decl)))
	    gimplify_type_sizes (TREE_TYPE (result_decl), pre_p);
	  /* Note that we don't use gimplify_vla_decl because the RESULT_DECL
	     should be effectively allocated by the caller, i.e. all calls to
	     this function must be subject to the Return Slot Optimization.  */
	  gimplify_one_sizepos (&DECL_SIZE (result_decl), pre_p);
	  gimplify_one_sizepos (&DECL_SIZE_UNIT (result_decl), pre_p);
	}
      result = result_decl;
    }
  else if (gimplify_ctxp->return_temp)
    result = gimplify_ctxp->return_temp;
  else
    {
      result = create_tmp_reg (TREE_TYPE (result_decl));

      /* ??? With complex control flow (usually involving abnormal edges),
	 we can wind up warning about an uninitialized value for this.  Due
	 to how this variable is constructed and initialized, this is never
	 true.  Give up and never warn.  */
      TREE_NO_WARNING (result) = 1;

      gimplify_ctxp->return_temp = result;
    }

  /* Smash the lhs of the MODIFY_EXPR to the temporary we plan to use.
     Then gimplify the whole thing.  */
  if (result != result_decl)
    TREE_OPERAND (ret_expr, 0) = result;

  gimplify_and_add (TREE_OPERAND (stmt, 0), pre_p);

  ret = gimple_build_return (result);
  gimple_set_no_warning (ret, TREE_NO_WARNING (stmt));
  gimplify_seq_add_stmt (pre_p, ret);

  return GS_ALL_DONE;
}

/* Gimplify a variable-length array DECL.  */

static void
gimplify_vla_decl (tree decl, gimple_seq *seq_p)
{
  /* This is a variable-sized decl.  Simplify its size and mark it
     for deferred expansion.  */
  tree t, addr, ptr_type;

  gimplify_one_sizepos (&DECL_SIZE (decl), seq_p);
  gimplify_one_sizepos (&DECL_SIZE_UNIT (decl), seq_p);

  /* Don't mess with a DECL_VALUE_EXPR set by the front-end.  */
  if (DECL_HAS_VALUE_EXPR_P (decl))
    return;

  /* All occurrences of this decl in final gimplified code will be
     replaced by indirection.  Setting DECL_VALUE_EXPR does two
     things: First, it lets the rest of the gimplifier know what
     replacement to use.  Second, it lets the debug info know
     where to find the value.  */
  ptr_type = build_pointer_type (TREE_TYPE (decl));
  addr = create_tmp_var (ptr_type, get_name (decl));
  DECL_IGNORED_P (addr) = 0;
  t = build_fold_indirect_ref (addr);
  TREE_THIS_NOTRAP (t) = 1;
  SET_DECL_VALUE_EXPR (decl, t);
  DECL_HAS_VALUE_EXPR_P (decl) = 1;

  t = builtin_decl_explicit (BUILT_IN_ALLOCA_WITH_ALIGN);
  t = build_call_expr (t, 2, DECL_SIZE_UNIT (decl),
		       size_int (DECL_ALIGN (decl)));
  /* The call has been built for a variable-sized object.  */
  CALL_ALLOCA_FOR_VAR_P (t) = 1;
  t = fold_convert (ptr_type, t);
  t = build2 (MODIFY_EXPR, TREE_TYPE (addr), addr, t);

  gimplify_and_add (t, seq_p);
}

/* A helper function to be called via walk_tree.  Mark all labels under *TP
   as being forced.  To be called for DECL_INITIAL of static variables.  */

static tree
force_labels_r (tree *tp, int *walk_subtrees, void *data ATTRIBUTE_UNUSED)
{
  if (TYPE_P (*tp))
    *walk_subtrees = 0;
  if (TREE_CODE (*tp) == LABEL_DECL)
    {
      FORCED_LABEL (*tp) = 1;
      cfun->has_forced_label_in_static = 1;
    }

  return NULL_TREE;
}

/* Gimplify a DECL_EXPR node *STMT_P by making any necessary allocation
   and initialization explicit.  */

static enum gimplify_status
gimplify_decl_expr (tree *stmt_p, gimple_seq *seq_p)
{
  tree stmt = *stmt_p;
  tree decl = DECL_EXPR_DECL (stmt);

  *stmt_p = NULL_TREE;

  if (TREE_TYPE (decl) == error_mark_node)
    return GS_ERROR;

  if ((TREE_CODE (decl) == TYPE_DECL
       || TREE_CODE (decl) == VAR_DECL)
      && !TYPE_SIZES_GIMPLIFIED (TREE_TYPE (decl)))
    {
      gimplify_type_sizes (TREE_TYPE (decl), seq_p);
      if (TREE_CODE (TREE_TYPE (decl)) == REFERENCE_TYPE)
	gimplify_type_sizes (TREE_TYPE (TREE_TYPE (decl)), seq_p);
    }

  /* ??? DECL_ORIGINAL_TYPE is streamed for LTO so it needs to be gimplified
     in case its size expressions contain problematic nodes like CALL_EXPR.  */
  if (TREE_CODE (decl) == TYPE_DECL
      && DECL_ORIGINAL_TYPE (decl)
      && !TYPE_SIZES_GIMPLIFIED (DECL_ORIGINAL_TYPE (decl)))
    {
      gimplify_type_sizes (DECL_ORIGINAL_TYPE (decl), seq_p);
      if (TREE_CODE (DECL_ORIGINAL_TYPE (decl)) == REFERENCE_TYPE)
	gimplify_type_sizes (TREE_TYPE (DECL_ORIGINAL_TYPE (decl)), seq_p);
    }

  if (TREE_CODE (decl) == VAR_DECL && !DECL_EXTERNAL (decl))
    {
      tree init = DECL_INITIAL (decl);

      if (TREE_CODE (DECL_SIZE_UNIT (decl)) != INTEGER_CST
	  || (!TREE_STATIC (decl)
	      && flag_stack_check == GENERIC_STACK_CHECK
	      && compare_tree_int (DECL_SIZE_UNIT (decl),
				   STACK_CHECK_MAX_VAR_SIZE) > 0))
	gimplify_vla_decl (decl, seq_p);

      /* Some front ends do not explicitly declare all anonymous
	 artificial variables.  We compensate here by declaring the
	 variables, though it would be better if the front ends would
	 explicitly declare them.  */
      if (!DECL_SEEN_IN_BIND_EXPR_P (decl)
	  && DECL_ARTIFICIAL (decl) && DECL_NAME (decl) == NULL_TREE)
	gimple_add_tmp_var (decl);

      if (init && init != error_mark_node)
	{
	  if (!TREE_STATIC (decl))
	    {
	      DECL_INITIAL (decl) = NULL_TREE;
	      init = build2 (INIT_EXPR, void_type_node, decl, init);
	      gimplify_and_add (init, seq_p);
	      ggc_free (init);
	    }
	  else
	    /* We must still examine initializers for static variables
	       as they may contain a label address.  */
	    walk_tree (&init, force_labels_r, NULL, NULL);
	}
    }

  return GS_ALL_DONE;
}

/* Gimplify a LOOP_EXPR.  Normally this just involves gimplifying the body
   and replacing the LOOP_EXPR with goto, but if the loop contains an
   EXIT_EXPR, we need to append a label for it to jump to.  */

static enum gimplify_status
gimplify_loop_expr (tree *expr_p, gimple_seq *pre_p)
{
  tree saved_label = gimplify_ctxp->exit_label;
  tree start_label = create_artificial_label (UNKNOWN_LOCATION);

  gimplify_seq_add_stmt (pre_p, gimple_build_label (start_label));

  gimplify_ctxp->exit_label = NULL_TREE;

  gimplify_and_add (LOOP_EXPR_BODY (*expr_p), pre_p);

  gimplify_seq_add_stmt (pre_p, gimple_build_goto (start_label));

  if (gimplify_ctxp->exit_label)
    gimplify_seq_add_stmt (pre_p,
			   gimple_build_label (gimplify_ctxp->exit_label));

  gimplify_ctxp->exit_label = saved_label;

  *expr_p = NULL;
  return GS_ALL_DONE;
}

/* Gimplify a statement list onto a sequence.  These may be created either
   by an enlightened front-end, or by shortcut_cond_expr.  */

static enum gimplify_status
gimplify_statement_list (tree *expr_p, gimple_seq *pre_p)
{
  tree temp = voidify_wrapper_expr (*expr_p, NULL);

  tree_stmt_iterator i = tsi_start (*expr_p);

  while (!tsi_end_p (i))
    {
      gimplify_stmt (tsi_stmt_ptr (i), pre_p);
      tsi_delink (&i);
    }

  if (temp)
    {
      *expr_p = temp;
      return GS_OK;
    }

  return GS_ALL_DONE;
}


/* Gimplify a SWITCH_EXPR, and collect the vector of labels it can
   branch to.  */

static enum gimplify_status
gimplify_switch_expr (tree *expr_p, gimple_seq *pre_p)
{
  tree switch_expr = *expr_p;
  gimple_seq switch_body_seq = NULL;
  enum gimplify_status ret;
  tree index_type = TREE_TYPE (switch_expr);
  if (index_type == NULL_TREE)
    index_type = TREE_TYPE (SWITCH_COND (switch_expr));

  ret = gimplify_expr (&SWITCH_COND (switch_expr), pre_p, NULL, is_gimple_val,
                       fb_rvalue);
  if (ret == GS_ERROR || ret == GS_UNHANDLED)
    return ret;

  if (SWITCH_BODY (switch_expr))
    {
      vec<tree> labels;
      vec<tree> saved_labels;
      tree default_case = NULL_TREE;
      gswitch *switch_stmt;

      /* If someone can be bothered to fill in the labels, they can
	 be bothered to null out the body too.  */
      gcc_assert (!SWITCH_LABELS (switch_expr));

      /* Save old labels, get new ones from body, then restore the old
         labels.  Save all the things from the switch body to append after.  */
      saved_labels = gimplify_ctxp->case_labels;
      gimplify_ctxp->case_labels.create (8);

      gimplify_stmt (&SWITCH_BODY (switch_expr), &switch_body_seq);
      labels = gimplify_ctxp->case_labels;
      gimplify_ctxp->case_labels = saved_labels;

      preprocess_case_label_vec_for_gimple (labels, index_type,
					    &default_case);

      if (!default_case)
	{
	  glabel *new_default;

	  default_case
	    = build_case_label (NULL_TREE, NULL_TREE,
				create_artificial_label (UNKNOWN_LOCATION));
	  new_default = gimple_build_label (CASE_LABEL (default_case));
	  gimplify_seq_add_stmt (&switch_body_seq, new_default);
	}

      switch_stmt = gimple_build_switch (SWITCH_COND (switch_expr),
					   default_case, labels);
      gimplify_seq_add_stmt (pre_p, switch_stmt);
      gimplify_seq_add_seq (pre_p, switch_body_seq);
      labels.release ();
    }
  else
    gcc_assert (SWITCH_LABELS (switch_expr));

  return GS_ALL_DONE;
}

/* Gimplify the CASE_LABEL_EXPR pointed to by EXPR_P.  */

static enum gimplify_status
gimplify_case_label_expr (tree *expr_p, gimple_seq *pre_p)
{
  struct gimplify_ctx *ctxp;
  glabel *label_stmt;

  /* Invalid programs can play Duff's Device type games with, for example,
     #pragma omp parallel.  At least in the C front end, we don't
     detect such invalid branches until after gimplification, in the
     diagnose_omp_blocks pass.  */
  for (ctxp = gimplify_ctxp; ; ctxp = ctxp->prev_context)
    if (ctxp->case_labels.exists ())
      break;

  label_stmt = gimple_build_label (CASE_LABEL (*expr_p));
  ctxp->case_labels.safe_push (*expr_p);
  gimplify_seq_add_stmt (pre_p, label_stmt);

  return GS_ALL_DONE;
}

/* Build a GOTO to the LABEL_DECL pointed to by LABEL_P, building it first
   if necessary.  */

tree
build_and_jump (tree *label_p)
{
  if (label_p == NULL)
    /* If there's nowhere to jump, just fall through.  */
    return NULL_TREE;

  if (*label_p == NULL_TREE)
    {
      tree label = create_artificial_label (UNKNOWN_LOCATION);
      *label_p = label;
    }

  return build1 (GOTO_EXPR, void_type_node, *label_p);
}

/* Gimplify an EXIT_EXPR by converting to a GOTO_EXPR inside a COND_EXPR.
   This also involves building a label to jump to and communicating it to
   gimplify_loop_expr through gimplify_ctxp->exit_label.  */

static enum gimplify_status
gimplify_exit_expr (tree *expr_p)
{
  tree cond = TREE_OPERAND (*expr_p, 0);
  tree expr;

  expr = build_and_jump (&gimplify_ctxp->exit_label);
  expr = build3 (COND_EXPR, void_type_node, cond, expr, NULL_TREE);
  *expr_p = expr;

  return GS_OK;
}

/* *EXPR_P is a COMPONENT_REF being used as an rvalue.  If its type is
   different from its canonical type, wrap the whole thing inside a
   NOP_EXPR and force the type of the COMPONENT_REF to be the canonical
   type.

   The canonical type of a COMPONENT_REF is the type of the field being
   referenced--unless the field is a bit-field which can be read directly
   in a smaller mode, in which case the canonical type is the
   sign-appropriate type corresponding to that mode.  */

static void
canonicalize_component_ref (tree *expr_p)
{
  tree expr = *expr_p;
  tree type;

  gcc_assert (TREE_CODE (expr) == COMPONENT_REF);

  if (INTEGRAL_TYPE_P (TREE_TYPE (expr)))
    type = TREE_TYPE (get_unwidened (expr, NULL_TREE));
  else
    type = TREE_TYPE (TREE_OPERAND (expr, 1));

  /* One could argue that all the stuff below is not necessary for
     the non-bitfield case and declare it a FE error if type
     adjustment would be needed.  */
  if (TREE_TYPE (expr) != type)
    {
#ifdef ENABLE_TYPES_CHECKING
      tree old_type = TREE_TYPE (expr);
#endif
      int type_quals;

      /* We need to preserve qualifiers and propagate them from
	 operand 0.  */
      type_quals = TYPE_QUALS (type)
	| TYPE_QUALS (TREE_TYPE (TREE_OPERAND (expr, 0)));
      if (TYPE_QUALS (type) != type_quals)
	type = build_qualified_type (TYPE_MAIN_VARIANT (type), type_quals);

      /* Set the type of the COMPONENT_REF to the underlying type.  */
      TREE_TYPE (expr) = type;

#ifdef ENABLE_TYPES_CHECKING
      /* It is now a FE error, if the conversion from the canonical
	 type to the original expression type is not useless.  */
      gcc_assert (useless_type_conversion_p (old_type, type));
#endif
    }
}

/* If a NOP conversion is changing a pointer to array of foo to a pointer
   to foo, embed that change in the ADDR_EXPR by converting
      T array[U];
      (T *)&array
   ==>
      &array[L]
   where L is the lower bound.  For simplicity, only do this for constant
   lower bound.
   The constraint is that the type of &array[L] is trivially convertible
   to T *.  */

static void
canonicalize_addr_expr (tree *expr_p)
{
  tree expr = *expr_p;
  tree addr_expr = TREE_OPERAND (expr, 0);
  tree datype, ddatype, pddatype;

  /* We simplify only conversions from an ADDR_EXPR to a pointer type.  */
  if (!POINTER_TYPE_P (TREE_TYPE (expr))
      || TREE_CODE (addr_expr) != ADDR_EXPR)
    return;

  /* The addr_expr type should be a pointer to an array.  */
  datype = TREE_TYPE (TREE_TYPE (addr_expr));
  if (TREE_CODE (datype) != ARRAY_TYPE)
    return;

  /* The pointer to element type shall be trivially convertible to
     the expression pointer type.  */
  ddatype = TREE_TYPE (datype);
  pddatype = build_pointer_type (ddatype);
  if (!useless_type_conversion_p (TYPE_MAIN_VARIANT (TREE_TYPE (expr)),
				  pddatype))
    return;

  /* The lower bound and element sizes must be constant.  */
  if (!TYPE_SIZE_UNIT (ddatype)
      || TREE_CODE (TYPE_SIZE_UNIT (ddatype)) != INTEGER_CST
      || !TYPE_DOMAIN (datype) || !TYPE_MIN_VALUE (TYPE_DOMAIN (datype))
      || TREE_CODE (TYPE_MIN_VALUE (TYPE_DOMAIN (datype))) != INTEGER_CST)
    return;

  /* All checks succeeded.  Build a new node to merge the cast.  */
  *expr_p = build4 (ARRAY_REF, ddatype, TREE_OPERAND (addr_expr, 0),
		    TYPE_MIN_VALUE (TYPE_DOMAIN (datype)),
		    NULL_TREE, NULL_TREE);
  *expr_p = build1 (ADDR_EXPR, pddatype, *expr_p);

  /* We can have stripped a required restrict qualifier above.  */
  if (!useless_type_conversion_p (TREE_TYPE (expr), TREE_TYPE (*expr_p)))
    *expr_p = fold_convert (TREE_TYPE (expr), *expr_p);
}

/* *EXPR_P is a NOP_EXPR or CONVERT_EXPR.  Remove it and/or other conversions
   underneath as appropriate.  */

static enum gimplify_status
gimplify_conversion (tree *expr_p)
{
  location_t loc = EXPR_LOCATION (*expr_p);
  gcc_assert (CONVERT_EXPR_P (*expr_p));

  /* Then strip away all but the outermost conversion.  */
  STRIP_SIGN_NOPS (TREE_OPERAND (*expr_p, 0));

  /* And remove the outermost conversion if it's useless.  */
  if (tree_ssa_useless_type_conversion (*expr_p))
    *expr_p = TREE_OPERAND (*expr_p, 0);

  /* If we still have a conversion at the toplevel,
     then canonicalize some constructs.  */
  if (CONVERT_EXPR_P (*expr_p))
    {
      tree sub = TREE_OPERAND (*expr_p, 0);

      /* If a NOP conversion is changing the type of a COMPONENT_REF
	 expression, then canonicalize its type now in order to expose more
	 redundant conversions.  */
      if (TREE_CODE (sub) == COMPONENT_REF)
	canonicalize_component_ref (&TREE_OPERAND (*expr_p, 0));

      /* If a NOP conversion is changing a pointer to array of foo
	 to a pointer to foo, embed that change in the ADDR_EXPR.  */
      else if (TREE_CODE (sub) == ADDR_EXPR)
	canonicalize_addr_expr (expr_p);
    }

  /* If we have a conversion to a non-register type force the
     use of a VIEW_CONVERT_EXPR instead.  */
  if (CONVERT_EXPR_P (*expr_p) && !is_gimple_reg_type (TREE_TYPE (*expr_p)))
    *expr_p = fold_build1_loc (loc, VIEW_CONVERT_EXPR, TREE_TYPE (*expr_p),
			       TREE_OPERAND (*expr_p, 0));

  /* Canonicalize CONVERT_EXPR to NOP_EXPR.  */
  if (TREE_CODE (*expr_p) == CONVERT_EXPR)
    TREE_SET_CODE (*expr_p, NOP_EXPR);

  return GS_OK;
}

/* Nonlocal VLAs seen in the current function.  */
static hash_set<tree> *nonlocal_vlas;

/* The VAR_DECLs created for nonlocal VLAs for debug info purposes.  */
static tree nonlocal_vla_vars;

/* Gimplify a VAR_DECL or PARM_DECL.  Return GS_OK if we expanded a
   DECL_VALUE_EXPR, and it's worth re-examining things.  */

static enum gimplify_status
gimplify_var_or_parm_decl (tree *expr_p)
{
  tree decl = *expr_p;

  /* ??? If this is a local variable, and it has not been seen in any
     outer BIND_EXPR, then it's probably the result of a duplicate
     declaration, for which we've already issued an error.  It would
     be really nice if the front end wouldn't leak these at all.
     Currently the only known culprit is C++ destructors, as seen
     in g++.old-deja/g++.jason/binding.C.  */
  if (TREE_CODE (decl) == VAR_DECL
      && !DECL_SEEN_IN_BIND_EXPR_P (decl)
      && !TREE_STATIC (decl) && !DECL_EXTERNAL (decl)
      && decl_function_context (decl) == current_function_decl)
    {
      gcc_assert (seen_error ());
      return GS_ERROR;
    }

  /* When within an OMP context, notice uses of variables.  */
  if (gimplify_omp_ctxp && omp_notice_variable (gimplify_omp_ctxp, decl, true))
    return GS_ALL_DONE;

  /* If the decl is an alias for another expression, substitute it now.  */
  if (DECL_HAS_VALUE_EXPR_P (decl))
    {
      tree value_expr = DECL_VALUE_EXPR (decl);

      /* For referenced nonlocal VLAs add a decl for debugging purposes
	 to the current function.  */
      if (TREE_CODE (decl) == VAR_DECL
	  && TREE_CODE (DECL_SIZE_UNIT (decl)) != INTEGER_CST
	  && nonlocal_vlas != NULL
	  && TREE_CODE (value_expr) == INDIRECT_REF
	  && TREE_CODE (TREE_OPERAND (value_expr, 0)) == VAR_DECL
	  && decl_function_context (decl) != current_function_decl)
	{
	  struct gimplify_omp_ctx *ctx = gimplify_omp_ctxp;
	  while (ctx
		 && (ctx->region_type == ORT_WORKSHARE
		     || ctx->region_type == ORT_SIMD
		     || ctx->region_type == ORT_ACC))
	    ctx = ctx->outer_context;
	  if (!ctx && !nonlocal_vlas->add (decl))
	    {
	      tree copy = copy_node (decl);

	      lang_hooks.dup_lang_specific_decl (copy);
	      SET_DECL_RTL (copy, 0);
	      TREE_USED (copy) = 1;
	      DECL_CHAIN (copy) = nonlocal_vla_vars;
	      nonlocal_vla_vars = copy;
	      SET_DECL_VALUE_EXPR (copy, unshare_expr (value_expr));
	      DECL_HAS_VALUE_EXPR_P (copy) = 1;
	    }
	}

      *expr_p = unshare_expr (value_expr);
      return GS_OK;
    }

  return GS_ALL_DONE;
}

/* Recalculate the value of the TREE_SIDE_EFFECTS flag for T.  */

static 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 ();
   }
}

/* Gimplify the COMPONENT_REF, ARRAY_REF, REALPART_EXPR or IMAGPART_EXPR
   node *EXPR_P.

      compound_lval
	      : min_lval '[' val ']'
	      | min_lval '.' ID
	      | compound_lval '[' val ']'
	      | compound_lval '.' ID

   This is not part of the original SIMPLE definition, which separates
   array and member references, but it seems reasonable to handle them
   together.  Also, this way we don't run into problems with union
   aliasing; gcc requires that for accesses through a union to alias, the
   union reference must be explicit, which was not always the case when we
   were splitting up array and member refs.

   PRE_P points to the sequence where side effects that must happen before
     *EXPR_P should be stored.

   POST_P points to the sequence where side effects that must happen after
     *EXPR_P should be stored.  */

static enum gimplify_status
gimplify_compound_lval (tree *expr_p, gimple_seq *pre_p, gimple_seq *post_p,
			fallback_t fallback)
{
  tree *p;
  enum gimplify_status ret = GS_ALL_DONE, tret;
  int i;
  location_t loc = EXPR_LOCATION (*expr_p);
  tree expr = *expr_p;

  /* Create a stack of the subexpressions so later we can walk them in
     order from inner to outer.  */
  auto_vec<tree, 10> expr_stack;

  /* We can handle anything that get_inner_reference can deal with.  */
  for (p = expr_p; ; p = &TREE_OPERAND (*p, 0))
    {
    restart:
      /* Fold INDIRECT_REFs now to turn them into ARRAY_REFs.  */
      if (TREE_CODE (*p) == INDIRECT_REF)
	*p = fold_indirect_ref_loc (loc, *p);

      if (handled_component_p (*p))
	;
      /* Expand DECL_VALUE_EXPR now.  In some cases that may expose
	 additional COMPONENT_REFs.  */