[libfirm] / ir / opt / scalar_replace.c

/*
 * Copyright (C) 1995-2008 University of Karlsruhe.  All right reserved.
 *
 * This file is part of libFirm.
 *
 * This file may be distributed and/or modified under the terms of the
 * GNU General Public License version 2 as published by the Free Software
 * Foundation and appearing in the file LICENSE.GPL included in the
 * packaging of this file.
 *
 * Licensees holding valid libFirm Professional Edition licenses may use
 * this file in accordance with the libFirm Commercial License.
 * Agreement provided with the Software.
 *
 * This file is provided AS IS with NO WARRANTY OF ANY KIND, INCLUDING THE
 * WARRANTY OF DESIGN, MERCHANTABILITY AND FITNESS FOR A PARTICULAR
 * PURPOSE.
 */

/**
 * @file
 * @brief   Scalar replacement of compounds.
 * @author  Beyhan Veliev, Michael Beck
 * @version $Id$
 */
#ifdef HAVE_CONFIG_H
#include "config.h"
#endif

#include <string.h>

#include "iroptimize.h"
#include "scalar_replace.h"
#include "irflag_t.h"
#include "irouts.h"
#include "set.h"
#include "pset.h"
#include "array.h"
#include "tv.h"
#include "ircons_t.h"
#include "hashptr.h"
#include "irgwalk.h"
#include "irgmod.h"
#include "irnode_t.h"
#include "irtools.h"
#include "xmalloc.h"

#define SET_VNUM(node, vnum) set_irn_link(node, INT_TO_PTR(vnum))
#define GET_VNUM(node)       (unsigned)PTR_TO_INT(get_irn_link(node))

/**
 * A path element entry: it is either an entity
 * or a tarval, because we evaluate only constant array
 * accesses like a.b.c[8].d
 */
typedef union {
        ir_entity *ent;
        tarval *tv;
} path_elem_t;

/**
 * An access path, used to assign value numbers
 * to variables that will be scalar replaced.
 */
typedef struct _path_t {
        unsigned    vnum;      /**< The value number. */
        unsigned    path_len;  /**< The length of the access path. */
        path_elem_t path[1];   /**< The path. */
} path_t;

/** The size of a path in bytes. */
#define PATH_SIZE(p)  (sizeof(*(p)) + sizeof((p)->path[0]) * ((p)->path_len - 1))

typedef struct _scalars_t {
        ir_entity *ent;              /**< A entity for scalar replacement. */
        ir_type *ent_owner;          /**< The owner of this entity. */
} scalars_t;


/**
 * Compare two pathes.
 *
 * @return 0 if they are identically
 */
static int path_cmp(const void *elt, const void *key, size_t size) {
        const path_t *p1 = elt;
        const path_t *p2 = key;
        (void) size;

        /* we can use memcmp here, because identical tarvals should have identical addresses */
        return memcmp(p1->path, p2->path, p1->path_len * sizeof(p1->path[0]));
}

/**
 * Compare two elements of the scalars_t set.
 *
 * @return 0 if they are identically
 */
static int ent_cmp(const void *elt, const void *key, size_t size) {
        const scalars_t *c1 = elt;
        const scalars_t *c2 = key;
        (void) size;

        return c1->ent != c2->ent;
}

/**
 * Calculate a hash value for a path.
 */
static unsigned path_hash(const path_t *path) {
        unsigned hash = 0;
        unsigned i;

        for (i = 0; i < path->path_len; ++i)
                hash ^= (unsigned)PTR_TO_INT(path->path[i].ent);

        return hash >> 4;
}

/**
 * Returns non-zero, if all indeces of a Sel node are constants.
 *
 * @param sel  the Sel node that will be checked
 */
static int is_const_sel(ir_node *sel) {
        int i, n = get_Sel_n_indexs(sel);

        for (i = 0; i < n; ++i) {
                ir_node *idx = get_Sel_index(sel, i);

                if (get_irn_op(idx) != op_Const)
                        return 0;
        }
        return 1;
}

/**
 * Check the mode of a Load/Store with the mode of the entity
 * that is accessed.
 * If the mode of the entity and the Load/Store mode do not match, we
 * have the bad reinterpret case:
 *
 * int i;
 * char b = *(char *)&i;
 *
 * We do NOT count this as one value and return address_taken
 * in that case.
 * However, we support an often used case. If the mode is two-complement
 * we allow casts between signed/unsigned.
 *
 * @param mode     the mode of the Load/Store
 * @param ent_mode the mode of the accessed entity
 */
static int check_load_store_mode(ir_mode *mode, ir_mode *ent_mode) {
        if (ent_mode != mode) {
                if (ent_mode == NULL ||
                    get_mode_size_bits(ent_mode) != get_mode_size_bits(mode) ||
                    get_mode_sort(ent_mode) != get_mode_sort(mode) ||
                    get_mode_arithmetic(ent_mode) != irma_twos_complement ||
                    get_mode_arithmetic(mode) != irma_twos_complement)
                        return 0;
        }
        return 1;
}

/*
 * Returns non-zero, if the address of an entity
 * represented by a Sel node (or it's successor Sels) is taken.
 */
int is_address_taken(ir_node *sel)
{
        int     i;
        ir_mode *emode, *mode;
        ir_node *value;
        ir_entity *ent;

        if (! is_const_sel(sel))
                return 1;

        for (i = get_irn_n_outs(sel) - 1; i >= 0; --i) {
                ir_node *succ = get_irn_out(sel, i);

                switch (get_irn_opcode(succ)) {
                case iro_Load:
                        /* check if this load is not a hidden conversion */
                        mode = get_Load_mode(succ);
                        ent = get_Sel_entity(sel);
                        emode = get_type_mode(get_entity_type(ent));
                        if (! check_load_store_mode(mode, emode))
                                return 1;
                        break;

                case iro_Store:
                        /* check that Sel is not the Store's value */
                        value = get_Store_value(succ);
                        if (value == sel)
                                return 1;
                        /* check if this Store is not a hidden conversion */
                        mode = get_irn_mode(value);
                        ent = get_Sel_entity(sel);
                        emode = get_type_mode(get_entity_type(ent));
                        if (! check_load_store_mode(mode, emode))
                                return 1;
                        break;

                case iro_Sel: {
                        /* Check the Sel successor of Sel */
                        int res = is_address_taken(succ);

                        if (res)
                                return 1;
                        break;
                }

                case iro_Call:
                        /* The address of an entity is given as a parameter.
                         * As long as we do not have analyses that can tell what
                         * is done with parameters, think is taken.
                         * One special case: If the Call type tells that it's a
                         * value parameter, the address is NOT taken.
                         */
                        return 1;

                default:
                        /* another op, the address is taken */
                        return 1;
                }
        }
        return 0;
}

/**
 * Link all leave Sels with the entity.
 *
 * @param ent  the entity that will be scalar replaced
 * @param sel  a Sel node that selects some fields of this entity
 */
static void link_all_leave_sels(ir_entity *ent, ir_node *sel) {
        int i, n, flag = 1;

        n = get_irn_n_outs(sel);
        for (i = 0; i < n; ++i) {
                ir_node *succ = get_irn_out(sel, i);

                if (is_Sel(succ)) {
                        link_all_leave_sels(ent, succ);
                        flag = 0;
                }
        }

        if (flag) {
                /* if Sel nodes with memory inputs are used, a entity can be
                 * visited more than once causing a ring here, so we use the
                 * node flag to mark linked nodes
                 */
                if (irn_visited(sel))
                        return;

                /* we know we are at a leave, because this function is only
                 * called if the address is NOT taken, so succ must be a Load
                 * or a Store node
                 */
                set_irn_link(sel, get_entity_link(ent));
                set_entity_link(ent, sel);

                mark_irn_visited(sel);
        }
}

/* we need a special address that serves as an address taken marker */
static char _x;
static void *ADDRESS_TAKEN = &_x;

/**
 * Find possible scalar replacements.
 *
 * @param irg  an IR graph
 *
 * This function finds variables on the (members of the) frame type
 * that can be scalar replaced, because their address is never taken.
 * If such a variable is found, it's entity link will hold a list of all
 * Sel nodes, that selects the atomic fields of this entity.
 * Otherwise, the link will be ADDRESS_TAKEN or NULL.
 *
 * @return  non-zero if at least one entity could be replaced
 *          potentially
 */
static int find_possible_replacements(ir_graph *irg) {
        ir_node *irg_frame = get_irg_frame(irg);
        int i, n;
        int res = 0;

        inc_irg_visited(irg);

        n = get_irn_n_outs(irg_frame);

        /*
         * First, clear the link field of all interesting entities.
         * Note that we did not rely on the fact that there is only
         * one Sel node per entity, so we might access one entity
         * more than once here.
         * That's why we have need two loops.
         */
        for (i = 0; i < n; ++i) {
                ir_node *succ = get_irn_out(irg_frame, i);

                if (is_Sel(succ)) {
                        ir_entity *ent = get_Sel_entity(succ);
                        set_entity_link(ent, NULL);
                }
        }

        /*
         * Check the ir_graph for Sel nodes. If the entity of Sel
         * isn't a scalar replacement set the link of this entity
         * equal ADDRESS_TAKEN.
         */
        for (i = 0; i < n; ++i) {
                ir_node *succ = get_irn_out(irg_frame, i);

                if (is_Sel(succ)) {
                        ir_entity *ent = get_Sel_entity(succ);
                        ir_type *ent_type;

                        if (get_entity_link(ent) == ADDRESS_TAKEN)
                                continue;

                        /*
                         * Beware: in rare cases even entities on the frame might be
                         * volatile. This might happen if the entity serves as a store
                         * to a value that must survive a exception. Do not optimize
                         * such entities away.
                         */
                        if (get_entity_volatility(ent) == volatility_is_volatile) {
                                set_entity_link(ent, ADDRESS_TAKEN);
                                continue;
                        }

                        ent_type = get_entity_type(ent);

                        /* we can handle arrays, structs and atomic types yet */
                        if (is_Array_type(ent_type) || is_Struct_type(ent_type) || is_atomic_type(ent_type)) {
                                if (is_address_taken(succ)) {
                                        if (get_entity_link(ent)) /* killing one */
                                                --res;
                                        set_entity_link(ent, ADDRESS_TAKEN);
                                } else {
                                        /* possible found one */
                                        if (get_entity_link(ent) == NULL)
                                                ++res;
                                        link_all_leave_sels(ent, succ);
                                }
                        }
                }
        }

        return res;
}

/**
 * Return a path from the Sel node sel to it's root.
 *
 * @param sel  the Sel node
 * @param len  the length of the path so far
 */
static path_t *find_path(ir_node *sel, unsigned len) {
        int pos, i, n;
        path_t *res;
        ir_node *pred = get_Sel_ptr(sel);

        /* the current Sel node will add some path elements */
        n    = get_Sel_n_indexs(sel);
        len += n + 1;

        if (! is_Sel(pred)) {
                /* we found the root */

                res = xmalloc(sizeof(*res) + (len - 1) * sizeof(res->path));
                res->path_len = len;
        } else
                res = find_path(pred, len);

        pos = res->path_len - len;

        res->path[pos++].ent = get_Sel_entity(sel);
        for (i = 0; i < n; ++i) {
                ir_node *index = get_Sel_index(sel, i);

                res->path[pos++].tv = get_Const_tarval(index);
        }
        return res;
}


/**
 * Allocate value numbers for the leaves
 * in our found entities.
 *
 * @param sels  a set that will contain all Sels that have a value number
 * @param ent   the entity that will be scalar replaced
 * @param vnum  the first value number we can assign
 * @param modes a flexible array, containing all the modes of
 *              the value numbers.
 *
 * @return the next free value number
 */
static unsigned allocate_value_numbers(pset *sels, ir_entity *ent, unsigned vnum, ir_mode ***modes)
{
        ir_node *sel, *next;
        path_t *key, *path;
        set *pathes = new_set(path_cmp, 8);

        /* visit all Sel nodes in the chain of the entity */
        for (sel = get_entity_link(ent); sel; sel = next) {
                next = get_irn_link(sel);

                /* we must mark this sel for later */
                pset_insert_ptr(sels, sel);

                key  = find_path(sel, 0);
                path = set_find(pathes, key, PATH_SIZE(key), path_hash(key));

                if (path)
                        SET_VNUM(sel, path->vnum);
                else {
                        key->vnum = vnum++;

                        set_insert(pathes, key, PATH_SIZE(key), path_hash(key));

                        SET_VNUM(sel, key->vnum);
                        ARR_EXTO(ir_mode *, *modes, (int)((key->vnum + 15) & ~15));

                        (*modes)[key->vnum] = get_type_mode(get_entity_type(get_Sel_entity(sel)));

                        assert((*modes)[key->vnum] && "Value is not atomic");

#ifdef DEBUG_libfirm
                        /* Debug output */
                        if (get_opt_scalar_replacement_verbose() && get_firm_verbosity() > 1) {
                                unsigned i;
                                printf("  %s", get_entity_name(key->path[0].ent));
                                for (i = 1; i < key->path_len; ++i) {
                                        if (is_entity(key->path[i].ent))
                                                printf(".%s", get_entity_name(key->path[i].ent));
                                        else
                                                printf("[%ld]", get_tarval_long(key->path[i].tv));
                                }
                                printf(" = %u (%s)\n", PTR_TO_INT(get_irn_link(sel)), get_mode_name((*modes)[key->vnum]));
                        }
#endif /* DEBUG_libfirm */
                }
                free(key);
        }

        del_set(pathes);
        set_entity_link(ent, NULL);
        return vnum;
}

/**
 * A list entry for the fixing lists
 */
typedef struct _list_entry_t {
        ir_node  *node;   /**< the node that must be fixed */
        unsigned vnum;    /**< the value number of this node */
} list_entry_t;

/**
 * environment for memory walker
 */
typedef struct _env_t {
        struct obstack obst;      /**< a obstack for the value blocks */
        int          nvals;       /**< number of values */
        ir_mode      **modes;     /**< the modes of the values */
        list_entry_t *fix_phis;   /**< list of all Phi nodes that must be fixed */
        list_entry_t *fix_loads;  /**< list of all Load nodes that must be fixed */
        pset         *sels;       /**< A set of all Sel nodes that have a value number */
} env_t;

/**
 * topological walker.
 */
static void topologic_walker(ir_node *node, void *ctx) {
        env_t        *env = ctx;
        ir_op        *op = get_irn_op(node);
        ir_node      *adr, *block, *mem, *unk, **value_arr, **in, *val;
        ir_mode      *mode;
        unsigned     vnum;
        int          i, j, n;
        list_entry_t *l;

        if (op == op_Load) {
                /* a load, check if we can resolve it */
                adr = get_Load_ptr(node);

                if (! is_Sel(adr))
                        return;

                if (! pset_find_ptr(env->sels, adr))
                        return;

                /* ok, we have a Load that will be replaced */
                vnum = GET_VNUM(adr);

                assert(vnum < (unsigned)env->nvals);

                block     = get_nodes_block(node);
                value_arr = get_irn_link(block);

                /* check, if we can replace this Load */
                if (value_arr[vnum]) {
                        mem = get_Load_mem(node);

                        /* Beware: A Load can contain a hidden conversion in Firm.
                        This happens for instance in the following code:

                         int i;
                         unsigned j = *(unsigned *)&i;

                        Handle this here. */
                        val = value_arr[vnum];
                        mode = get_Load_mode(node);
                        if (mode != get_irn_mode(val))
                                val = new_d_Conv(get_irn_dbg_info(node), val, mode);

                        turn_into_tuple(node, pn_Load_max);
                        set_Tuple_pred(node, pn_Load_M,         mem);
                        set_Tuple_pred(node, pn_Load_res,       val);
                        set_Tuple_pred(node, pn_Load_X_regular, new_r_Jmp(current_ir_graph, block));
                        set_Tuple_pred(node, pn_Load_X_except,  new_Bad());
                } else {
                        l = obstack_alloc(&env->obst, sizeof(*l));
                        l->node = node;
                        l->vnum = vnum;

                        set_irn_link(node, env->fix_loads);
                        env->fix_loads = l;
                }
        } else if (op == op_Store) {
                /* a Store always can be replaced */
                adr = get_Store_ptr(node);

                if (! is_Sel(adr))
                        return;

                if (! pset_find_ptr(env->sels, adr))
                        return;

                vnum = GET_VNUM(adr);

                assert(vnum < (unsigned)env->nvals);

                block     = get_nodes_block(node);
                value_arr = get_irn_link(block);

                /* Beware: A Store can contain a hidden conversion in Firm. */
                val = get_Store_value(node);
                if (get_irn_mode(val) != env->modes[vnum])
                        val = new_d_Conv(get_irn_dbg_info(node), val, env->modes[vnum]);
                value_arr[vnum] = val;

                mem = get_Store_mem(node);
                block = get_nodes_block(node);

                turn_into_tuple(node, pn_Store_max);
                set_Tuple_pred(node, pn_Store_M,         mem);
                set_Tuple_pred(node, pn_Store_X_regular, new_r_Jmp(current_ir_graph, block));
                set_Tuple_pred(node, pn_Store_X_except,  new_Bad());
        } else if (op == op_Phi && get_irn_mode(node) == mode_M) {
                /*
                 * found a memory Phi: Here, we must create new Phi nodes
                 */
                block     = get_nodes_block(node);
                value_arr = get_irn_link(block);

                n = get_Block_n_cfgpreds(block);

                in = alloca(sizeof(*in) * n);

                for (i = env->nvals - 1; i >= 0; --i) {
                        unk = new_Unknown(env->modes[i]);
                        for (j = n - 1; j >= 0; --j)
                                in[j] = unk;

                        value_arr[i] = new_r_Phi(current_ir_graph, block, n, in, env->modes[i]);

                        l = obstack_alloc(&env->obst, sizeof(*l));
                        l->node = value_arr[i];
                        l->vnum = i;

                        set_irn_link(value_arr[i], env->fix_phis);
                        env->fix_phis = l;
                }
        }
}

/**
 * Walker: allocate the value array for every block.
 */
static void alloc_value_arr(ir_node *block, void *ctx) {
        env_t *env = ctx;
        ir_node **var_arr = obstack_alloc(&env->obst, sizeof(*var_arr) * env->nvals);

        /* the value array is empty at start */
        memset(var_arr, 0, sizeof(*var_arr) * env->nvals);
        set_irn_link(block, var_arr);
}

/**
 * searches through blocks beginning from block for value
 * vnum and return it.
 */
static ir_node *find_vnum_value(ir_node *block, unsigned vnum) {
        ir_node **value_arr;
        int i;
        ir_node *res;

        if (Block_not_block_visited(block)) {
                mark_Block_block_visited(block);

                value_arr = get_irn_link(block);

                if (value_arr[vnum])
                        return value_arr[vnum];

                for (i = get_Block_n_cfgpreds(block) - 1; i >= 0; --i) {
                        ir_node *pred = get_Block_cfgpred(block, i);

                        res = find_vnum_value(get_nodes_block(pred), vnum);
                        if (res)
                                return res;
                }
        }
        return NULL;
}

/**
 * fix the Phi list
 */
static void fix_phis(env_t *env) {
        list_entry_t *l;
        ir_node      *phi, *block, *pred, *val;
        int          i;

        for (l = env->fix_phis; l; l = get_irn_link(phi)) {
                phi = l->node;

                block = get_nodes_block(phi);
                for (i = get_irn_arity(phi) - 1; i >= 0; --i) {
                        pred = get_Block_cfgpred(block, i);
                        pred = get_nodes_block(pred);

                        inc_irg_block_visited(current_ir_graph);
                        val = find_vnum_value(pred, l->vnum);

                        if (val)
                                set_irn_n(phi, i, val);
                }
        }
}

/**
 * fix the Load list
 */
static void fix_loads(env_t *env) {
        list_entry_t *l;
        ir_node      *load, *block, *pred, *val = NULL, *mem;
        ir_mode      *mode;
        int          i;

        for (l = env->fix_loads; l; l = get_irn_link(load)) {
                load = l->node;

                block = get_nodes_block(load);
                for (i = get_Block_n_cfgpreds(block) - 1; i >= 0; --i) {
                        pred = get_Block_cfgpred(block, i);
                        pred = get_nodes_block(pred);

                        inc_irg_block_visited(current_ir_graph);
                        val = find_vnum_value(pred, l->vnum);

                        if (val)
                                break;
                }

                if (! val) {
                        /* access of an uninitialized value */
                        val = new_Unknown(env->modes[l->vnum]);
                }

                /* Beware: A Load can contain a hidden conversion in Firm.
                   Handle this here. */
                mode = get_Load_mode(load);
                if (mode != get_irn_mode(val))
                        val = new_d_Conv(get_irn_dbg_info(load), val, mode);

                mem = get_Load_mem(load);

                turn_into_tuple(load, pn_Load_max);
                set_Tuple_pred(load, pn_Load_M,         mem);
                set_Tuple_pred(load, pn_Load_res,       val);
                set_Tuple_pred(load, pn_Load_X_regular, new_r_Jmp(current_ir_graph, block));
                set_Tuple_pred(load, pn_Load_X_except,  new_Bad());
        }
}

/**
 *  Make scalar replacement.
 *
 * @param sels    A set containing all Sel nodes that have a value number
 * @param nvals   The number of scalars.
 * @param modes   A flexible array, containing all the modes of
 *                the value numbers.
 */
static void do_scalar_replacements(pset *sels, int nvals, ir_mode **modes) {
        env_t env;

        obstack_init(&env.obst);
        env.nvals     = nvals;
        env.modes     = modes;
        env.fix_phis  = NULL;
        env.fix_loads = NULL;
        env.sels      = sels;

        /* first step: allocate the value arrays for every block */
        irg_block_walk_graph(current_ir_graph, NULL, alloc_value_arr, &env);

        /*
         * second step: walk over the graph blockwise in topological order
         * and fill the array as much as possible.
         */
        irg_walk_blkwise_graph(current_ir_graph, NULL, topologic_walker, &env);

        /* third, fix the list of Phis, then the list of Loads */
        fix_phis(&env);
        fix_loads(&env);

        obstack_free(&env.obst, NULL);
}

/*
 * Find possible scalar replacements
 *
 * @param irg  The current ir graph.
 */
void scalar_replacement_opt(ir_graph *irg) {
        unsigned  nvals;
        int       i;
        scalars_t key, *value;
        ir_node   *irg_frame;
        ir_mode   **modes;
        set       *set_ent;
        pset      *sels;
        ir_type   *ent_type;
        ir_graph  *rem;

        if (! get_opt_scalar_replacement())
                return;

        rem = current_ir_graph;

        /* Call algorithm that computes the out edges */
        assure_irg_outs(irg);

        /* Find possible scalar replacements */
        if (find_possible_replacements(irg)) {

                if (get_opt_scalar_replacement_verbose()) {
                        printf("Scalar Replacement: %s\n", get_entity_name(get_irg_entity(irg)));
                }

                /* Insert in set the scalar replacements. */
                irg_frame = get_irg_frame(irg);
                nvals = 0;
                modes = NEW_ARR_F(ir_mode *, 16);
                set_ent = new_set(ent_cmp, 8);
                sels    = pset_new_ptr(8);

                for (i = 0 ; i < get_irn_n_outs(irg_frame); i++) {
                        ir_node *succ = get_irn_out(irg_frame, i);

                        if (is_Sel(succ)) {
                                ir_entity *ent = get_Sel_entity(succ);

                                if (get_entity_link(ent) == NULL || get_entity_link(ent) == ADDRESS_TAKEN)
                                        continue;

                                ent_type = get_entity_type(ent);

                                key.ent       = ent;
                                key.ent_owner = get_entity_owner(ent);
                                set_insert(set_ent, &key, sizeof(key), HASH_PTR(key.ent));

                                if (get_opt_scalar_replacement_verbose()) {
                                        if (is_Array_type(ent_type)) {
                                                printf("  found array %s\n", get_entity_name(ent));
                                        }
                                        else if (is_Struct_type(ent_type)) {
                                                printf("  found struct %s\n", get_entity_name(ent));
                                        }
                                        else if (is_atomic_type(ent_type))
                                                printf("  found atomic value %s\n", get_entity_name(ent));
                                        else {
                                                assert(0 && "Neither an array nor a struct or atomic value");
                                        }
                                }

                                nvals = allocate_value_numbers(sels, ent, nvals, &modes);
                        }
                }

                if (get_opt_scalar_replacement_verbose()) {
                        printf("  %u values will be needed\n", nvals);
                }

                /* If scalars were found. */
                if (nvals) {
                        do_scalar_replacements(sels, nvals, modes);

                        for (value = set_first(set_ent); value; value = set_next(set_ent)) {
                                remove_class_member(value->ent_owner, value->ent);
                        }
                }

                del_pset(sels);
                del_set(set_ent);
                DEL_ARR_F(modes);

                if (nvals) {
                        /*
                         * We changed the graph, but did NOT introduce new blocks
                         * neither changed control flow, cf-backedges should be still
                         * consistent.
                         */
                        set_irg_outs_inconsistent(irg);
                        set_irg_loopinfo_inconsistent(irg);
                }
        }

        current_ir_graph = rem;
}