[libfirm] / ir / be / becopyopt.c

/*
 * Copyright (C) 1995-2007 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       Copy minimization driver.
 * @author      Daniel Grund
 * @date        12.04.2005
 * @version     $Id$
 *
 * Main file for the optimization reducing the copies needed for:
 * - Phi coalescing
 * - Register-constrained nodes
 * - Two-address code instructions
 */
#ifdef HAVE_CONFIG_H
#include "config.h"
#endif

#include "execfreq.h"
#include "xmalloc.h"
#include "debug.h"
#include "pmap.h"
#include "raw_bitset.h"
#include "irgraph.h"
#include "irgwalk.h"
#include "irprog.h"
#include "irloop_t.h"
#include "iredges_t.h"
#include "phiclass.h"
#include "irbitset.h"
#include "irphase_t.h"
#include "irprintf_t.h"

#include "bemodule.h"
#include "bearch_t.h"
#include "benode_t.h"
#include "beutil.h"
#include "beifg_t.h"
#include "becopyopt_t.h"
#include "becopystat.h"
#include "belive_t.h"
#include "beinsn_t.h"
#include "besched_t.h"
#include "benodesets.h"
#include "bejavacoal.h"
#include "bestatevent.h"
#include "beirg_t.h"
#include "error.h"
#include "bera.h"

#include <libcore/lc_timing.h>
#include <libcore/lc_opts.h>
#include <libcore/lc_opts_enum.h>

#define DUMP_BEFORE 1
#define DUMP_AFTER  2
#define DUMP_APPEL  4
#define DUMP_ALL    2 * DUMP_APPEL - 1

#define COST_FUNC_FREQ     1
#define COST_FUNC_LOOP     2
#define COST_FUNC_ALL_ONE  3

static unsigned   dump_flags  = 0;
static unsigned   style_flags = 0;
static unsigned   do_stats    = 0;
static cost_fct_t cost_func   = co_get_costs_exec_freq;
static unsigned   algo        = CO_ALGO_HEUR4;
static int        improve     = 1;

static const lc_opt_enum_mask_items_t dump_items[] = {
        { "before",  DUMP_BEFORE },
        { "after",   DUMP_AFTER  },
        { "appel",   DUMP_APPEL  },
        { "all",     DUMP_ALL    },
        { NULL,      0 }
};

static const lc_opt_enum_mask_items_t style_items[] = {
        { "color",   CO_IFG_DUMP_COLORS },
        { "labels",  CO_IFG_DUMP_LABELS },
        { "constr",  CO_IFG_DUMP_CONSTR },
        { "shape",   CO_IFG_DUMP_SHAPE  },
        { "full",    2 * CO_IFG_DUMP_SHAPE - 1 },
        { NULL,      0 }
};

static const lc_opt_enum_mask_items_t algo_items[] = {
        { "none",   CO_ALGO_NONE  },
        { "heur",   CO_ALGO_HEUR  },
        { "heur2",  CO_ALGO_HEUR2 },
#ifdef WITH_JVM
        { "heur3",  CO_ALGO_HEUR3 },
#endif /* WITH_JVM */
        { "heur4",  CO_ALGO_HEUR4 },
#ifdef WITH_ILP
        { "ilp",    CO_ALGO_ILP   },
#endif /* WITH_ILP */
        { NULL,     0 }
};

typedef int (*opt_funcptr)(void);

static const lc_opt_enum_func_ptr_items_t cost_func_items[] = {
        { "freq",   (opt_funcptr) co_get_costs_exec_freq },
        { "loop",   (opt_funcptr) co_get_costs_loop_depth },
        { "one",    (opt_funcptr) co_get_costs_all_one },
        { NULL,     NULL }
};

static lc_opt_enum_mask_var_t dump_var = {
        &dump_flags, dump_items
};

static lc_opt_enum_mask_var_t style_var = {
        &style_flags, style_items
};

static lc_opt_enum_mask_var_t algo_var = {
        &algo, algo_items
};

static lc_opt_enum_func_ptr_var_t cost_func_var = {
        (opt_funcptr*) &cost_func, cost_func_items
};

static const lc_opt_table_entry_t options[] = {
        LC_OPT_ENT_ENUM_INT      ("algo",    "select copy optimization algo",                           &algo_var),
        LC_OPT_ENT_ENUM_FUNC_PTR ("cost",    "select a cost function",                                  &cost_func_var),
        LC_OPT_ENT_ENUM_MASK     ("dump",    "dump ifg before or after copy optimization",              &dump_var),
        LC_OPT_ENT_ENUM_MASK     ("style",   "dump style for ifg dumping",                              &style_var),
        LC_OPT_ENT_BOOL          ("stats",   "dump statistics after each optimization",                 &do_stats),
        LC_OPT_ENT_BOOL          ("improve", "run heur3 before if algo can exploit start solutions",    &improve),
        { NULL }
};

/* Insert additional options registration functions here. */
extern void be_co_ilp_register_options(lc_opt_entry_t *grp);
extern void be_co2_register_options(lc_opt_entry_t *grp);
extern void be_co3_register_options(lc_opt_entry_t *grp);

void be_init_copycoal(void)
{
        lc_opt_entry_t *be_grp = lc_opt_get_grp(firm_opt_get_root(), "be");
        lc_opt_entry_t *ra_grp = lc_opt_get_grp(be_grp, "ra");
        lc_opt_entry_t *chordal_grp = lc_opt_get_grp(ra_grp, "chordal");
        lc_opt_entry_t *co_grp = lc_opt_get_grp(chordal_grp, "co");

        lc_opt_add_table(co_grp, options);
}

BE_REGISTER_MODULE_CONSTRUCTOR(be_init_copycoal);

#undef QUICK_AND_DIRTY_HACK

static int nodes_interfere(const be_chordal_env_t *env, const ir_node *a, const ir_node *b)
{
        if (env->ifg)
                return be_ifg_connected(env->ifg, a, b);
        else
                return values_interfere(env->birg->lv, a, b);
}


/******************************************************************************
    _____                           _
   / ____|                         | |
  | |  __  ___ _ __   ___ _ __ __ _| |
  | | |_ |/ _ \ '_ \ / _ \ '__/ _` | |
  | |__| |  __/ | | |  __/ | | (_| | |
   \_____|\___|_| |_|\___|_|  \__,_|_|

 ******************************************************************************/

DEBUG_ONLY(static firm_dbg_module_t *dbg = NULL;)


copy_opt_t *new_copy_opt(be_chordal_env_t *chordal_env, cost_fct_t get_costs)
{
        const char *s1, *s2, *s3;
        int len;
        copy_opt_t *co;

        FIRM_DBG_REGISTER(dbg, "ir.be.copyopt");

        co = xcalloc(1, sizeof(*co));
        co->cenv      = chordal_env;
        co->aenv      = chordal_env->birg->main_env->arch_env;
        co->irg       = chordal_env->irg;
        co->cls       = chordal_env->cls;
        co->get_costs = get_costs;

        s1 = get_irp_prog_name();
        s2 = get_entity_name(get_irg_entity(co->irg));
        s3 = chordal_env->cls->name;
        len = strlen(s1) + strlen(s2) + strlen(s3) + 5;
        co->name = xmalloc(len);
        snprintf(co->name, len, "%s__%s__%s", s1, s2, s3);

        return co;
}

void free_copy_opt(copy_opt_t *co) {
        xfree(co->name);
        free(co);
}

int co_is_optimizable_root(const copy_opt_t *co, ir_node *irn) {
        const arch_register_req_t *req;
        const arch_register_t *reg;

        if (arch_irn_is(co->aenv, irn, ignore))
                return 0;

        reg = arch_get_irn_register(co->aenv, irn);
        if (arch_register_type_is(reg, ignore))
                return 0;

        req = arch_get_register_req(co->aenv, irn, -1);
        if (is_Reg_Phi(irn) || is_Perm_Proj(co->aenv, irn) || is_2addr_code(req))
                return 1;

        return 0;
}

int co_is_optimizable_arg(const copy_opt_t *co, ir_node *irn) {
        const ir_edge_t *edge;
        const arch_register_t *reg;

        assert(0 && "Is buggy and obsolete. Do not use");

        if (arch_irn_is(co->aenv, irn, ignore))
                return 0;

        reg = arch_get_irn_register(co->aenv, irn);
        if (arch_register_type_is(reg, ignore))
                return 0;

        foreach_out_edge(irn, edge) {
                ir_node *n = edge->src;

                if (!nodes_interfere(co->cenv, irn, n) || irn == n) {
                        const arch_register_req_t *req;
                        req = arch_get_register_req(co->aenv, n, -1);

                        if(is_Reg_Phi(n) ||
                           is_Perm(co->aenv, n) ||
                           (arch_register_req_is(req, should_be_same))) {
                                ir_node *other = get_irn_n(irn, req->other_same);
                                if(other == irn)
                                        return 1;
                        }
                }
        }

        return 0;
}

int co_get_costs_loop_depth(const copy_opt_t *co, ir_node *root, ir_node* arg, int pos) {
        int cost = 0;
        ir_loop *loop;
        ir_node *root_block = get_nodes_block(root);

        if (is_Phi(root)) {
                /* for phis the copies are placed in the corresponding pred-block */
                loop = get_irn_loop(get_Block_cfgpred_block(root_block, pos));
        } else {
                /* a perm places the copy in the same block as it resides */
                loop = get_irn_loop(root_block);
        }
        if (loop) {
                int d = get_loop_depth(loop);
                cost = d*d;
        }
        return 1+cost;
}

int co_get_costs_exec_freq(const copy_opt_t *co, ir_node *root, ir_node* arg, int pos) {
        int res;
        ir_node *root_bl = get_nodes_block(root);
        ir_node *copy_bl = is_Phi(root) ? get_Block_cfgpred_block(root_bl, pos) : root_bl;
        res = get_block_execfreq_ulong(co->cenv->birg->exec_freq, copy_bl);

        /* don't allow values smaller than one. */
        return res < 1 ? 1 : res;
}


int co_get_costs_all_one(const copy_opt_t *co, ir_node *root, ir_node *arg, int pos) {
        return 1;
}

/******************************************************************************
   ____        _   _    _       _ _          _____ _
  / __ \      | | | |  | |     (_) |        / ____| |
 | |  | |_ __ | |_| |  | |_ __  _| |_ ___  | (___ | |_ ___  _ __ __ _  __ _  ___
 | |  | | '_ \| __| |  | | '_ \| | __/ __|  \___ \| __/ _ \| '__/ _` |/ _` |/ _ \
 | |__| | |_) | |_| |__| | | | | | |_\__ \  ____) | || (_) | | | (_| | (_| |  __/
  \____/| .__/ \__|\____/|_| |_|_|\__|___/ |_____/ \__\___/|_|  \__,_|\__, |\___|
        | |                                                            __/ |
        |_|                                                           |___/
 ******************************************************************************/

/**
 * Determines a maximum weighted independent set with respect to
 * the interference and conflict edges of all nodes in a qnode.
 */
static int ou_max_ind_set_costs(unit_t *ou) {
        be_chordal_env_t *chordal_env = ou->co->cenv;
        ir_node **safe, **unsafe;
        int i, o, safe_count, safe_costs, unsafe_count, *unsafe_costs;
        bitset_t *curr;
        int max, pos, curr_weight, best_weight = 0;

        /* assign the nodes into two groups.
         * safe: node has no interference, hence it is in every max stable set.
         * unsafe: node has an interference
         */
        safe = alloca((ou->node_count-1) * sizeof(*safe));
        safe_costs = 0;
        safe_count = 0;
        unsafe = alloca((ou->node_count-1) * sizeof(*unsafe));
        unsafe_costs = alloca((ou->node_count-1) * sizeof(*unsafe_costs));
        unsafe_count = 0;
        for(i=1; i<ou->node_count; ++i) {
                int is_safe = 1;
                for(o=1; o<ou->node_count; ++o) {
                        if (i==o)
                                continue;
                        if (nodes_interfere(chordal_env, ou->nodes[i], ou->nodes[o])) {
                                unsafe_costs[unsafe_count] = ou->costs[i];
                                unsafe[unsafe_count] = ou->nodes[i];
                                ++unsafe_count;
                                is_safe = 0;
                                break;
                        }
                }
                if (is_safe) {
                        safe_costs += ou->costs[i];
                        safe[safe_count++] = ou->nodes[i];
                }
        }


        /* now compute the best set out of the unsafe nodes*/
        if (unsafe_count > MIS_HEUR_TRIGGER) {
                bitset_t *best = bitset_alloca(unsafe_count);
                /* Heuristik: Greedy trial and error form index 0 to unsafe_count-1 */
                for (i=0; i<unsafe_count; ++i) {
                        bitset_set(best, i);
                        /* check if it is a stable set */
                        for (o=bitset_next_set(best, 0); o!=-1 && o<i; o=bitset_next_set(best, o+1))
                                if (nodes_interfere(chordal_env, unsafe[i], unsafe[o])) {
                                        bitset_clear(best, i); /* clear the bit and try next one */
                                        break;
                                }
                }
                /* compute the weight */
                bitset_foreach(best, pos)
                        best_weight += unsafe_costs[pos];
        } else {
                /* Exact Algorithm: Brute force */
                curr = bitset_alloca(unsafe_count);
                bitset_set_all(curr);
                while ((max = bitset_popcnt(curr)) != 0) {
                        /* check if curr is a stable set */
                        for (i=bitset_next_set(curr, 0); i!=-1; i=bitset_next_set(curr, i+1))
                                for (o=bitset_next_set(curr, i+1); o!=-1; o=bitset_next_set(curr, o+1)) /* !!!!! difference to qnode_max_ind_set(): NOT (curr, i) */
                                                if (nodes_interfere(chordal_env, unsafe[i], unsafe[o]))
                                                        goto no_stable_set;

                        /* if we arrive here, we have a stable set */
                        /* compute the weigth of the stable set*/
                        curr_weight = 0;
                        bitset_foreach(curr, pos)
                                curr_weight += unsafe_costs[pos];

                        /* any better ? */
                        if (curr_weight > best_weight) {
                                best_weight = curr_weight;
                        }

        no_stable_set:
                        bitset_minus1(curr);
                }
        }

        return safe_costs+best_weight;
}

static void co_collect_units(ir_node *irn, void *env) {
        copy_opt_t *co = env;
        unit_t *unit;

        if (!is_curr_reg_class(co, irn))
                return;
        if (!co_is_optimizable_root(co, irn))
                return;

        /* Init a new unit */
        unit = xcalloc(1, sizeof(*unit));
        unit->co = co;
        unit->node_count = 1;
        INIT_LIST_HEAD(&unit->queue);

        /* Phi with some/all of its arguments */
        if (is_Reg_Phi(irn)) {
                int i, arity;

                /* init */
                arity = get_irn_arity(irn);
                unit->nodes = xmalloc((arity+1) * sizeof(*unit->nodes));
                unit->costs = xmalloc((arity+1) * sizeof(*unit->costs));
                unit->nodes[0] = irn;

                /* fill */
                for (i=0; i<arity; ++i) {
                        int o, arg_pos;
                        ir_node *arg = get_irn_n(irn, i);

                        assert(is_curr_reg_class(co, arg) && "Argument not in same register class.");
                        if (arg == irn)
                                continue;
                        if (nodes_interfere(co->cenv, irn, arg)) {
                                unit->inevitable_costs += co->get_costs(co, irn, arg, i);
                                continue;
                        }

                        /* Else insert the argument of the phi to the members of this ou */
                        DBG((dbg, LEVEL_1, "\t   Member: %+F\n", arg));

                        if (! arch_irn_is(co->aenv, arg, ignore)) {
                                /* Check if arg has occurred at a prior position in the arg/list */
                                arg_pos = 0;
                                for (o=1; o<unit->node_count; ++o) {
                                        if (unit->nodes[o] == arg) {
                                                arg_pos = o;
                                                break;
                                        }
                                }

                                if (!arg_pos) { /* a new argument */
                                        /* insert node, set costs */
                                        unit->nodes[unit->node_count] = arg;
                                        unit->costs[unit->node_count] = co->get_costs(co, irn, arg, i);
                                        unit->node_count++;
                                } else { /* arg has occured before in same phi */
                                        /* increase costs for existing arg */
                                        unit->costs[arg_pos] += co->get_costs(co, irn, arg, i);
                                }
                        }
                }
                unit->nodes = xrealloc(unit->nodes, unit->node_count * sizeof(*unit->nodes));
                unit->costs = xrealloc(unit->costs, unit->node_count * sizeof(*unit->costs));
        } else

        /* Proj of a perm with corresponding arg */
        if (is_Perm_Proj(co->aenv, irn)) {
                assert(!nodes_interfere(co->cenv, irn, get_Perm_src(irn)));
                unit->nodes = xmalloc(2 * sizeof(*unit->nodes));
                unit->costs = xmalloc(2 * sizeof(*unit->costs));
                unit->node_count = 2;
                unit->nodes[0] = irn;
                unit->nodes[1] = get_Perm_src(irn);
                unit->costs[1] = co->get_costs(co, irn, unit->nodes[1], -1);
        } else {
                const arch_register_req_t *req =
                        arch_get_register_req(co->aenv, irn, -1);

                /* Src == Tgt of a 2-addr-code instruction */
                if (is_2addr_code(req)) {
                        ir_node *other = get_irn_n(irn, req->other_same);
                        if (!arch_irn_is(co->aenv, other, ignore) &&
                                        !nodes_interfere(co->cenv, irn, other)) {
                                unit->nodes = xmalloc(2 * sizeof(*unit->nodes));
                                unit->costs = xmalloc(2 * sizeof(*unit->costs));
                                unit->node_count = 2;
                                unit->nodes[0] = irn;
                                unit->nodes[1] = other;
                                unit->costs[1] = co->get_costs(co, irn, other, -1);
                        }
                } else {
                        assert(0 && "This is not an optimizable node!");
                }
        }

        /* Insert the new unit at a position according to its costs */
        if (unit->node_count > 1) {
                int i;
                struct list_head *tmp;

                /* Determine the maximum costs this unit can cause: all_nodes_cost */
                for(i=1; i<unit->node_count; ++i) {
                        unit->sort_key = MAX(unit->sort_key, unit->costs[i]);
                        unit->all_nodes_costs += unit->costs[i];
                }

                /* Determine the minimal costs this unit will cause: min_nodes_costs */
                unit->min_nodes_costs += unit->all_nodes_costs - ou_max_ind_set_costs(unit);
                /* Insert the new ou according to its sort_key */
                tmp = &co->units;
                while (tmp->next != &co->units && list_entry_units(tmp->next)->sort_key > unit->sort_key)
                        tmp = tmp->next;
                list_add(&unit->units, tmp);
        } else {
                free(unit);
        }
}

#ifdef QUICK_AND_DIRTY_HACK

static int compare_ous(const void *k1, const void *k2) {
        const unit_t *u1 = *((const unit_t **) k1);
        const unit_t *u2 = *((const unit_t **) k2);
        int i, o, u1_has_constr, u2_has_constr;
        arch_register_req_t req;
        const arch_env_t *aenv = u1->co->aenv;

        /* Units with constraints come first */
        u1_has_constr = 0;
        for (i=0; i<u1->node_count; ++i) {
                arch_get_register_req(aenv, &req, u1->nodes[i], -1);
                if (arch_register_req_is(&req, limited)) {
                        u1_has_constr = 1;
                        break;
                }
        }

        u2_has_constr = 0;
        for (i=0; i<u2->node_count; ++i) {
                arch_get_register_req(aenv, &req, u2->nodes[i], -1);
                if (arch_register_req_is(&req, limited)) {
                        u2_has_constr = 1;
                        break;
                }
        }

        if (u1_has_constr != u2_has_constr)
                return u2_has_constr - u1_has_constr;

        /* Now check, whether the two units are connected */
#if 0
        for (i=0; i<u1->node_count; ++i)
                for (o=0; o<u2->node_count; ++o)
                        if (u1->nodes[i] == u2->nodes[o])
                                return 0;
#endif

        /* After all, the sort key decides. Greater keys come first. */
        return u2->sort_key - u1->sort_key;

}

/**
 * Sort the ou's according to constraints and their sort_key
 */
static void co_sort_units(copy_opt_t *co) {
        int i, count = 0, costs;
        unit_t *ou, **ous;

        /* get the number of ous, remove them form the list and fill the array */
        list_for_each_entry(unit_t, ou, &co->units, units)
                count++;
        ous = alloca(count * sizeof(*ous));

        costs = co_get_max_copy_costs(co);

        i = 0;
        list_for_each_entry(unit_t, ou, &co->units, units)
                ous[i++] = ou;

        INIT_LIST_HEAD(&co->units);

        assert(count == i && list_empty(&co->units));

        for (i=0; i<count; ++i)
                ir_printf("%+F\n", ous[i]->nodes[0]);

        qsort(ous, count, sizeof(*ous), compare_ous);

        ir_printf("\n\n");
        for (i=0; i<count; ++i)
                ir_printf("%+F\n", ous[i]->nodes[0]);

        /* reinsert into list in correct order */
        for (i=0; i<count; ++i)
                list_add_tail(&ous[i]->units, &co->units);

        assert(costs == co_get_max_copy_costs(co));
}
#endif

void co_build_ou_structure(copy_opt_t *co) {
        DBG((dbg, LEVEL_1, "\tCollecting optimization units\n"));
        INIT_LIST_HEAD(&co->units);
        irg_walk_graph(co->irg, co_collect_units, NULL, co);
#ifdef QUICK_AND_DIRTY_HACK
        co_sort_units(co);
#endif
}

void co_free_ou_structure(copy_opt_t *co) {
        unit_t *curr, *tmp;
        ASSERT_OU_AVAIL(co);
        list_for_each_entry_safe(unit_t, curr, tmp, &co->units, units) {
                xfree(curr->nodes);
                xfree(curr->costs);
                xfree(curr);
        }
        co->units.next = NULL;
}

/* co_solve_heuristic() is implemented in becopyheur.c */

int co_get_max_copy_costs(const copy_opt_t *co) {
        int i, res = 0;
        unit_t *curr;

        ASSERT_OU_AVAIL(co);

        list_for_each_entry(unit_t, curr, &co->units, units) {
                res += curr->inevitable_costs;
                for (i=1; i<curr->node_count; ++i)
                        res += curr->costs[i];
        }
        return res;
}

int co_get_inevit_copy_costs(const copy_opt_t *co) {
        int res = 0;
        unit_t *curr;

        ASSERT_OU_AVAIL(co);

        list_for_each_entry(unit_t, curr, &co->units, units)
                res += curr->inevitable_costs;
        return res;
}

int co_get_copy_costs(const copy_opt_t *co) {
        int i, res = 0;
        unit_t *curr;

        ASSERT_OU_AVAIL(co);

        list_for_each_entry(unit_t, curr, &co->units, units) {
                int root_col = get_irn_col(co, curr->nodes[0]);
                DBG((dbg, LEVEL_1, "  %3d costs for root %+F color %d\n", curr->inevitable_costs, curr->nodes[0], root_col));
                res += curr->inevitable_costs;
                for (i=1; i<curr->node_count; ++i) {
                        int arg_col = get_irn_col(co, curr->nodes[i]);
                        if (root_col != arg_col) {
                                DBG((dbg, LEVEL_1, "  %3d for arg %+F color %d\n", curr->costs[i], curr->nodes[i], arg_col));
                                res += curr->costs[i];
                        }
                }
        }
        return res;
}

int co_get_lower_bound(const copy_opt_t *co) {
        int res = 0;
        unit_t *curr;

        ASSERT_OU_AVAIL(co);

        list_for_each_entry(unit_t, curr, &co->units, units)
                res += curr->inevitable_costs + curr->min_nodes_costs;
        return res;
}

void co_complete_stats(const copy_opt_t *co, co_complete_stats_t *stat)
{
        bitset_t *seen = bitset_irg_malloc(co->irg);
        affinity_node_t *an;

        memset(stat, 0, sizeof(stat[0]));

        /* count affinity edges. */
        co_gs_foreach_aff_node(co, an) {
                neighb_t *neigh;
                stat->aff_nodes += 1;
                bitset_add_irn(seen, an->irn);
                co_gs_foreach_neighb(an, neigh) {
                        if(!bitset_contains_irn(seen, neigh->irn)) {
                                stat->aff_edges += 1;
                                stat->max_costs += neigh->costs;

                                if(get_irn_col(co, an->irn) != get_irn_col(co, neigh->irn)) {
                                        stat->costs += neigh->costs;
                                        stat->unsatisfied_edges += 1;
                                }

                                if(nodes_interfere(co->cenv, an->irn, neigh->irn)) {
                                        stat->aff_int += 1;
                                        stat->inevit_costs += neigh->costs;
                                }

                        }
                }
        }

        bitset_free(seen);
}

/******************************************************************************
   _____                 _        _____ _
  / ____|               | |      / ____| |
 | |  __ _ __ __ _ _ __ | |__   | (___ | |_ ___  _ __ __ _  __ _  ___
 | | |_ | '__/ _` | '_ \| '_ \   \___ \| __/ _ \| '__/ _` |/ _` |/ _ \
 | |__| | | | (_| | |_) | | | |  ____) | || (_) | | | (_| | (_| |  __/
  \_____|_|  \__,_| .__/|_| |_| |_____/ \__\___/|_|  \__,_|\__, |\___|
                  | |                                       __/ |
                  |_|                                      |___/
 ******************************************************************************/

static int compare_affinity_node_t(const void *k1, const void *k2, size_t size) {
        const affinity_node_t *n1 = k1;
        const affinity_node_t *n2 = k2;

        return (n1->irn != n2->irn);
}

static void add_edge(copy_opt_t *co, ir_node *n1, ir_node *n2, int costs) {
        affinity_node_t new_node, *node;
        neighb_t new_nbr, *nbr;
        int allocnew;

        new_node.irn        = n1;
        new_node.degree     = 0;
        new_node.neighbours = NULL;
        node = set_insert(co->nodes, &new_node, sizeof(new_node), nodeset_hash(new_node.irn));

        allocnew = 1;
        for (nbr = node->neighbours; nbr; nbr = nbr->next)
                if (nbr->irn == n2) {
                        allocnew = 0;
                        break;
                }

        /* if we did not find n2 in n1's neighbourhood insert it */
        if (allocnew) {
                obstack_grow(&co->obst, &new_nbr, sizeof(new_nbr));
                nbr = obstack_finish(&co->obst);
                nbr->irn   = n2;
                nbr->costs = 0;
                nbr->next  = node->neighbours;
                node->neighbours = nbr;
                node->degree++;
        }

        /* now nbr points to n1's neighbour-entry of n2 */
        nbr->costs += costs;
}

static INLINE void add_edges(copy_opt_t *co, ir_node *n1, ir_node *n2, int costs) {
        if (! be_ifg_connected(co->cenv->ifg, n1, n2)) {
                add_edge(co, n1, n2, costs);
                add_edge(co, n2, n1, costs);
        }
}

static void build_graph_walker(ir_node *irn, void *env) {
        copy_opt_t *co = env;
        int pos, max;
        const arch_register_t *reg;

        if (!is_curr_reg_class(co, irn) || arch_irn_is(co->aenv, irn, ignore))
                return;

        reg = arch_get_irn_register(co->aenv, irn);
        if (arch_register_type_is(reg, ignore))
                return;

        /* Phis */
        if (is_Reg_Phi(irn))
                for (pos=0, max=get_irn_arity(irn); pos<max; ++pos) {
                        ir_node *arg = get_irn_n(irn, pos);
                        add_edges(co, irn, arg, co->get_costs(co, irn, arg, pos));
                }

        /* Perms */
        else if (is_Perm_Proj(co->aenv, irn)) {
                ir_node *arg = get_Perm_src(irn);
                add_edges(co, irn, arg, co->get_costs(co, irn, arg, 0));
        }

        /* 2-address code */
        else {
                const arch_register_req_t *req =
                        arch_get_register_req(co->aenv, irn, -1);
                if (is_2addr_code(req)) {
                        ir_node *other = get_irn_n(irn, req->other_same);
                        if(!arch_irn_is(co->aenv, other, ignore))
                                add_edges(co, irn, other, co->get_costs(co, irn, other, 0));
                }
        }
}

void co_build_graph_structure(copy_opt_t *co) {
        obstack_init(&co->obst);
        co->nodes = new_set(compare_affinity_node_t, 32);

        irg_walk_graph(co->irg, build_graph_walker, NULL, co);
}

void co_free_graph_structure(copy_opt_t *co) {
        ASSERT_GS_AVAIL(co);

        del_set(co->nodes);
        obstack_free(&co->obst, NULL);
        co->nodes = NULL;
}

/* co_solve_ilp1() co_solve_ilp2() are implemented in becopyilpX.c */

int co_gs_is_optimizable(copy_opt_t *co, ir_node *irn) {
        affinity_node_t new_node, *n;

        ASSERT_GS_AVAIL(co);

        new_node.irn = irn;
        n = set_find(co->nodes, &new_node, sizeof(new_node), nodeset_hash(new_node.irn));
        if (n) {
                return (n->degree > 0);
        } else
                return 0;
}

void co_dump_appel_graph(const copy_opt_t *co, FILE *f)
{
        be_ifg_t *ifg  = co->cenv->ifg;
        int *color_map = alloca(co->cls->n_regs * sizeof(color_map[0]));

        ir_node *irn;
        void *it, *nit;
        int i, n, n_regs;

        n_regs = 0;
        for(i = 0; i < co->cls->n_regs; ++i) {
                const arch_register_t *reg = &co->cls->regs[i];
                color_map[i] = arch_register_type_is(reg, ignore) ? -1 : n_regs++;
        }

        /*
         * n contains the first node number.
         * the values below n are the pre-colored register nodes
         */

        it  = be_ifg_nodes_iter_alloca(ifg);
        nit = be_ifg_neighbours_iter_alloca(ifg);

        n = n_regs;
        be_ifg_foreach_node(ifg, it, irn) {
                if(!arch_irn_is(co->aenv, irn, ignore))
                        set_irn_link(irn, INT_TO_PTR(n++));
        }

        fprintf(f, "%d %d\n", n, n_regs);

        be_ifg_foreach_node(ifg, it, irn) {
                if(!arch_irn_is(co->aenv, irn, ignore)) {
                        int idx            = PTR_TO_INT(get_irn_link(irn));
                        affinity_node_t *a = get_affinity_info(co, irn);

                        const arch_register_req_t *req;
                        ir_node *adj;

                        req = arch_get_register_req(co->aenv, irn, BE_OUT_POS(0));
                        if(arch_register_req_is(req, limited)) {
                                for(i = 0; i < co->cls->n_regs; ++i) {
                                        if(!rbitset_is_set(req->limited, i) && color_map[i] >= 0)
                                                fprintf(f, "%d %d -1\n", color_map[i], idx);
                                }
                        }


                        be_ifg_foreach_neighbour(ifg, nit, irn, adj) {
                                if(!arch_irn_is(co->aenv, adj, ignore)) {
                                        int adj_idx = PTR_TO_INT(get_irn_link(adj));
                                        if(idx < adj_idx)
                                                fprintf(f, "%d %d -1\n", idx, adj_idx);
                                }
                        }

                        if(a) {
                                neighb_t *n;

                                co_gs_foreach_neighb(a, n) {
                                        if(!arch_irn_is(co->aenv, n->irn, ignore)) {
                                                int n_idx = PTR_TO_INT(get_irn_link(n->irn));
                                                if(idx < n_idx)
                                                        fprintf(f, "%d %d %d\n", idx, n_idx, (int) n->costs);
                                        }
                                }
                        }
                }
        }
}

typedef struct _appel_clique_walker_t {
        ir_phase ph;
        const copy_opt_t *co;
        int curr_nr;
        int node_count;
        FILE *f;
        int dumb;
        int *color_map;
        struct obstack obst;
} appel_clique_walker_t;

typedef struct _appel_block_info_t {
        int *live_end_nr;
        int *live_in_nr;
        int *phi_nr;
        ir_node **live_end;
        ir_node **live_in;
        ir_node **phi;
        int n_live_end;
        int n_live_in;
        int n_phi;
} appel_block_info_t;

static int appel_aff_weight(const appel_clique_walker_t *env, ir_node *bl)
{
#if 0
        double freq = get_block_execfreq(env->co->cenv->execfreq, bl);
        int res = (int) freq;
        return res == 0 ? 1 : res;
#else
        ir_loop *loop = get_irn_loop(bl);
        if(loop) {
                int d = get_loop_depth(loop);
                return 1 + d * d;
        }
        return 1;
#endif
}

static void *appel_clique_walker_irn_init(ir_phase *phase, ir_node *irn, void *old)
{
        appel_block_info_t *res = NULL;

        if(is_Block(irn)) {
                appel_clique_walker_t *d = (void *) phase;
                res = phase_alloc(phase, sizeof(res[0]));
                res->phi_nr      = phase_alloc(phase, d->co->cls->n_regs * sizeof(res->live_end_nr));
                res->live_end_nr = phase_alloc(phase, d->co->cls->n_regs * sizeof(res->live_end_nr));
                res->live_in_nr  = phase_alloc(phase, d->co->cls->n_regs * sizeof(res->live_in_nr));
                res->live_end    = phase_alloc(phase, d->co->cls->n_regs * sizeof(res->live_end));
                res->live_in     = phase_alloc(phase, d->co->cls->n_regs * sizeof(res->live_in));
                res->phi         = phase_alloc(phase, d->co->cls->n_regs * sizeof(res->live_in));
        }

        return res;
}

typedef struct _insn_list_t {
        be_insn_t *insn;
        struct list_head list;
} insn_list_t;

static int appel_get_live_end_nr(appel_clique_walker_t *env, ir_node *bl, ir_node *irn)
{
        appel_block_info_t *bli = phase_get_irn_data(&env->ph, bl);
        int i;

        for(i = 0; i < bli->n_live_end; ++i)
                if(bli->live_end[i] == irn)
                        return bli->live_end_nr[i];

        return -1;
}

static int appel_dump_clique(appel_clique_walker_t *env, pset *live, ir_node *bl, int curr_nr, int start_nr)
{
        ir_node **live_arr = alloca(env->co->cls->n_regs * sizeof(live_arr[0]));
        ir_node *irn;
        int n_live;
        int j;

        n_live = 0;
        foreach_pset(live, irn)
                live_arr[n_live++] = irn;

        /* dump the live after clique */
        if(!env->dumb) {
                for(j = 0; j < n_live; ++j) {
                        int k;

                        for(k = j + 1; k < n_live; ++k) {
                                fprintf(env->f, "%d %d -1 ", curr_nr + j, curr_nr + k);
                        }
                        fprintf(env->f, "\n");
                }
        }

        /* dump the affinities */
        for(j = 0; !env->dumb && j < n_live; ++j) {
                ir_node *irn = live_arr[j];
                int old_nr = PTR_TO_INT(get_irn_link(irn));

                /* if the node was already live in the last insn dump the affinity */
                if(old_nr > start_nr) {
                        int weight = appel_aff_weight(env, bl);
                        fprintf(env->f, "%d %d %d\n", old_nr, curr_nr + j, weight);
                }
        }

        /* set the current numbers into the link field. */
        for(j = 0; j < n_live; ++j) {
                ir_node *irn = live_arr[j];
                set_irn_link(irn, INT_TO_PTR(curr_nr + j));
        }

        return curr_nr + n_live;
}

static void appel_walker(ir_node *bl, void *data)
{
        appel_clique_walker_t *env = data;
        appel_block_info_t *bli    = phase_get_or_set_irn_data(&env->ph, bl);
        struct obstack *obst       = &env->obst;
        void *base                 = obstack_base(obst);
        pset *live                 = pset_new_ptr_default();
        be_lv_t *lv                = env->co->cenv->birg->lv;

        int n_insns  = 0;
        int n_nodes  = 0;
        int start_nr = env->curr_nr;
        int curr_nr  = start_nr;

        be_insn_env_t insn_env;
        int i, j;
        ir_node *irn;
        be_insn_t **insns;

        insn_env.aenv = env->co->aenv;
        insn_env.cls  = env->co->cls;
        insn_env.obst = obst;
        insn_env.ignore_colors = env->co->cenv->ignore_colors;

        /* Guess how many insns will be in this block. */
        sched_foreach(bl, irn)
                n_nodes++;

        bli->n_phi = 0;
        insns = malloc(n_nodes * sizeof(insns[0]));

        /* Put all insns in an array. */
        irn = sched_first(bl);
        while(!sched_is_end(irn)) {
                be_insn_t *insn;
                insn = be_scan_insn(&insn_env, irn);
                insns[n_insns++] = insn;
                irn = insn->next_insn;
        }

        DBG((dbg, LEVEL_2, "%+F\n", bl));
        be_liveness_end_of_block(lv, env->co->aenv, env->co->cls, bl, live);

        /* Generate the bad and ugly. */
        for(i = n_insns - 1; i >= 0; --i) {
                be_insn_t *insn = insns[i];

                /* The first live set has to be saved in the block border set. */
                if(i == n_insns - 1) {
                        j = 0;
                        foreach_pset(live, irn) {
                                bli->live_end[j]    = irn;
                                bli->live_end_nr[j] = curr_nr + j;
                                ++j;
                        }
                        bli->n_live_end = j;
                }

                if(!env->dumb) {
                        for(j = 0; j < insn->use_start; ++j) {
                                ir_node *op   = insn->ops[j].carrier;
                                bitset_t *adm = insn->ops[j].regs;
                                int k;
                                int nr;

                                if(!insn->ops[j].has_constraints)
                                        continue;

                                nr = 0;
                                foreach_pset(live, irn) {
                                        if(irn == op) {
                                                pset_break(live);
                                                break;
                                        }
                                        ++nr;
                                }

                                assert(nr < pset_count(live));

                                for(k = 0; k < env->co->cls->n_regs; ++k) {
                                        int mapped_col = env->color_map[k];
                                        if(mapped_col >= 0 && !bitset_is_set(adm, k) && !bitset_is_set(env->co->cenv->ignore_colors, k))
                                                fprintf(env->f, "%d %d -1\n", curr_nr + nr, mapped_col);
                                }
                        }
                }

                /* dump the clique and update the stuff. */
                curr_nr = appel_dump_clique(env, live, bl, curr_nr, start_nr);

                /* remove all defs. */
                for(j = 0; j < insn->use_start; ++j)
                        pset_remove_ptr(live, insn->ops[j].carrier);

                if(is_Phi(insn->irn) && arch_irn_consider_in_reg_alloc(env->co->aenv, env->co->cls, insn->irn)) {
                        bli->phi[bli->n_phi]    = insn->irn;
                        bli->phi_nr[bli->n_phi] = PTR_TO_INT(get_irn_link(insn->irn));
                        bli->n_phi++;
                }

                /* add all uses */
                else
                        for(j = insn->use_start; j < insn->n_ops; ++j)
                                pset_insert_ptr(live, insn->ops[j].carrier);
        }

        /* print the start clique. */
        curr_nr = appel_dump_clique(env, live, bl, curr_nr, start_nr);

        i = 0;
        foreach_pset(live, irn) {
                bli->live_in[i]    = irn;
                bli->live_in_nr[i] = PTR_TO_INT(get_irn_link(irn));
                ++i;
        }
        bli->n_live_in = i;

        del_pset(live);
        free(insns);
        obstack_free(obst, base);
        env->curr_nr = curr_nr;
}

static void appel_inter_block_aff(ir_node *bl, void *data)
{
        appel_clique_walker_t *env = data;
        appel_block_info_t *bli    = phase_get_irn_data(&env->ph, bl);

        int i, j, n;

        for(i = 0; i < bli->n_live_in; ++i) {
                ir_node *irn = bli->live_in[i];

                for(j = 0, n = get_Block_n_cfgpreds(bl); j < n; ++j) {
                        ir_node *pred  = get_Block_cfgpred_block(bl, j);

                        int nr = appel_get_live_end_nr(env, pred, irn);
                        assert(nr >= 0);
                        fprintf(env->f, "%d %d 1\n", bli->live_in_nr[i], nr);
                }
        }

        for(i = 0; i < bli->n_phi; ++i) {
                ir_node *irn = bli->phi[i];

                for(j = 0, n = get_Block_n_cfgpreds(bl); j < n; ++j) {
                        ir_node *pred  = get_Block_cfgpred_block(bl, j);
                        ir_node *op = get_irn_n(irn, j);

                        int nr = appel_get_live_end_nr(env, pred, op);
                        assert(nr >= 0);
                        fprintf(env->f, "%d %d 1\n", bli->phi_nr[i], nr);
                }
        }

}

void co_dump_appel_graph_cliques(const copy_opt_t *co, FILE *f)
{
        int i;
        int n_colors;
        appel_clique_walker_t env;
        bitset_t *adm = bitset_alloca(co->cls->n_regs);
        be_lv_t *lv = co->cenv->birg->lv;

        be_liveness_recompute(lv);
        obstack_init(&env.obst);
        phase_init(&env.ph, "appel_clique_dumper", co->irg, PHASE_DEFAULT_GROWTH, appel_clique_walker_irn_init, NULL);
        env.curr_nr = co->cls->n_regs;
        env.co = co;
        env.f = f;

        bitset_copy(adm, co->cenv->ignore_colors);
        bitset_flip_all(adm);

        /* Make color map. */
        env.color_map = alloca(co->cls->n_regs * sizeof(env.color_map[0]));
        for(i = 0, n_colors = 0; i < co->cls->n_regs; ++i) {
                const arch_register_t *reg = &co->cls->regs[i];
                env.color_map[i] = arch_register_type_is(reg, ignore) ? -1 : n_colors++;
        }

        env.dumb = 1;
        env.curr_nr = n_colors;
        irg_block_walk_graph(co->irg, firm_clear_link, NULL, NULL);
        irg_block_walk_graph(co->irg, appel_walker, NULL, &env);

        fprintf(f, "%d %d\n", env.curr_nr, n_colors);

        /* make the first k nodes interfere */
        for(i = 0; i < n_colors; ++i) {
                int j;
                for(j = i + 1; j < n_colors; ++j)
                        fprintf(f, "%d %d -1 ", i, j);
                fprintf(f, "\n");
        }

        env.dumb = 0;
        env.curr_nr = n_colors;
        irg_block_walk_graph(co->irg, firm_clear_link, NULL, NULL);
        irg_block_walk_graph(co->irg, appel_walker, NULL, &env);
        irg_block_walk_graph(co->irg, appel_inter_block_aff, NULL, &env);
        obstack_free(&env.obst, NULL);
}

/*
         ___ _____ ____   ____   ___ _____   ____                        _
        |_ _|  ___/ ___| |  _ \ / _ \_   _| |  _ \ _   _ _ __ ___  _ __ (_)_ __   __ _
         | || |_ | |  _  | | | | | | || |   | | | | | | | '_ ` _ \| '_ \| | '_ \ / _` |
         | ||  _|| |_| | | |_| | |_| || |   | |_| | |_| | | | | | | |_) | | | | | (_| |
        |___|_|   \____| |____/ \___/ |_|   |____/ \__,_|_| |_| |_| .__/|_|_| |_|\__, |
                                                                  |_|            |___/
*/

static const char *get_dot_color_name(int col)
{
        static const char *names[] = {
                "blue",
                "red",
                "green",
                "yellow",
                "cyan",
                "magenta",
                "orange",
                "chocolate",
                "beige",
                "navy",
                "darkgreen",
                "darkred",
                "lightPink",
                "chartreuse",
                "lightskyblue",
                "linen",
                "pink",
                "lightslateblue",
                "mintcream",
                "red",
                "darkolivegreen",
                "mediumblue",
                "mistyrose",
                "salmon",
                "darkseagreen",
                "mediumslateblue"
                "moccasin",
                "tomato",
                "forestgreen",
                "darkturquoise",
                "palevioletred"
        };

        return col < sizeof(names)/sizeof(names[0]) ? names[col] : "white";
}

typedef struct _co_ifg_dump_t {
        const copy_opt_t *co;
        unsigned flags;
} co_ifg_dump_t;

static void ifg_dump_graph_attr(FILE *f, void *self)
{
        fprintf(f, "overlap=scale");
}

static int ifg_is_dump_node(void *self, ir_node *irn)
{
        co_ifg_dump_t *cod = self;
        return !arch_irn_is(cod->co->aenv, irn, ignore);
}

static void ifg_dump_node_attr(FILE *f, void *self, ir_node *irn)
{
        co_ifg_dump_t *env         = self;
        const arch_register_t *reg = arch_get_irn_register(env->co->aenv, irn);
        const arch_register_req_t *req;
        int limited;

        req = arch_get_register_req(env->co->aenv, irn, BE_OUT_POS(0));
        limited = arch_register_req_is(req, limited);

        if(env->flags & CO_IFG_DUMP_LABELS) {
                ir_fprintf(f, "label=\"%+F", irn);

#if 0
                // TODO fix this...
                if((env->flags & CO_IFG_DUMP_CONSTR) && limited) {
                        bitset_t *bs = bitset_alloca(env->co->cls->n_regs);
                        req.limited(req.limited_env, bs);
                        ir_fprintf(f, "\\n%B", bs);
                }
#endif
                ir_fprintf(f, "\" ");
        } else {
                fprintf(f, "label=\"\" shape=point " );
        }

        if(env->flags & CO_IFG_DUMP_SHAPE)
                fprintf(f, "shape=%s ", limited ? "diamond" : "ellipse");

        if(env->flags & CO_IFG_DUMP_COLORS)
                fprintf(f, "style=filled color=%s ", get_dot_color_name(reg->index));
}

static void ifg_dump_at_end(FILE *file, void *self)
{
        co_ifg_dump_t *env = self;
        affinity_node_t *a;

        co_gs_foreach_aff_node(env->co, a) {
                const arch_register_t *ar = arch_get_irn_register(env->co->aenv, a->irn);
                unsigned aidx = get_irn_idx(a->irn);
                neighb_t *n;

                co_gs_foreach_neighb(a, n) {
                        const arch_register_t *nr = arch_get_irn_register(env->co->aenv, n->irn);
                        unsigned nidx = get_irn_idx(n->irn);

                        if(aidx < nidx) {
                                const char *color = nr == ar ? "blue" : "red";
                                fprintf(file, "\tn%d -- n%d [weight=0.01 ", aidx, nidx);
                                if(env->flags & CO_IFG_DUMP_LABELS)
                                        fprintf(file, "label=\"%d\" ", n->costs);
                                if(env->flags & CO_IFG_DUMP_COLORS)
                                        fprintf(file, "color=%s ", color);
                                else
                                        fprintf(file, "style=dotted");
                                fprintf(file, "];\n");
                        }
                }
        }
}


static be_ifg_dump_dot_cb_t ifg_dot_cb = {
        ifg_is_dump_node,
        ifg_dump_graph_attr,
        ifg_dump_node_attr,
        NULL,
        NULL,
        ifg_dump_at_end
};



void co_dump_ifg_dot(const copy_opt_t *co, FILE *f, unsigned flags)
{
        co_ifg_dump_t cod;

        cod.co    = co;
        cod.flags = flags;
        be_ifg_dump_dot(co->cenv->ifg, co->irg, f, &ifg_dot_cb, &cod);
}


void co_solve_park_moon(copy_opt_t *opt)
{

}

static int void_algo(copy_opt_t *co)
{
        return 0;
}

/*
                _    _                  _ _   _
           / \  | | __ _  ___  _ __(_) |_| |__  _ __ ___  ___
          / _ \ | |/ _` |/ _ \| '__| | __| '_ \| '_ ` _ \/ __|
         / ___ \| | (_| | (_) | |  | | |_| | | | | | | | \__ \
        /_/   \_\_|\__, |\___/|_|  |_|\__|_| |_|_| |_| |_|___/
                           |___/
*/

typedef struct {
        co_algo_t  *algo;
        const char *name;
        int        can_improve_existing;
} co_algo_info_t;

static co_algo_info_t algos[] = {
        { void_algo,               "none",  0 },
        { co_solve_heuristic,      "heur1", 0 },
        { co_solve_heuristic_new,  "heur2", 0 },
        { co_solve_heuristic_java, "heur3", 0 },
        { co_solve_heuristic_mst,  "heur4", 0 },
#ifdef WITH_ILP
        { co_solve_ilp2,           "ilp",   1 },
#endif
        { NULL,                    "",      0 }
};

/*
    __  __       _         ____       _
   |  \/  | __ _(_)_ __   |  _ \ _ __(_)_   _____ _ __
   | |\/| |/ _` | | '_ \  | | | | '__| \ \ / / _ \ '__|
   | |  | | (_| | | | | | | |_| | |  | |\ V /  __/ |
   |_|  |_|\__,_|_|_| |_| |____/|_|  |_| \_/ \___|_|

*/

static FILE *my_open(const be_chordal_env_t *env, const char *prefix, const char *suffix)
{
        FILE *result;
        char buf[1024];

        ir_snprintf(buf, sizeof(buf), "%s%F_%s%s", prefix, env->irg, env->cls->name, suffix);
        result = fopen(buf, "wt");
        if(result == NULL) {
                panic("Couldn't open '%s' for writing.", buf);
        }

        return result;
}

void co_driver(be_chordal_env_t *cenv)
{
        lc_timer_t          *timer = lc_timer_register("firm.be.copyopt", "runtime");
        co_complete_stats_t before, after;
        copy_opt_t          *co;
        co_algo_t           *algo_func;
        int                 was_optimal = 0;

        if (algo < 0 || algo >= CO_ALGO_LAST)
                return;

        co = new_copy_opt(cenv, cost_func);
        co_build_ou_structure(co);
        co_build_graph_structure(co);

        co_complete_stats(co, &before);

        be_stat_ev_ull("co_aff_nodes",    before.aff_nodes);
        be_stat_ev_ull("co_aff_edges",    before.aff_edges);
        be_stat_ev_ull("co_max_costs",    before.max_costs);
        be_stat_ev_ull("co_inevit_costs", before.inevit_costs);
        be_stat_ev_ull("co_aff_int",      before.aff_int);

        be_stat_ev_ull("co_init_costs",   before.costs);
        be_stat_ev_ull("co_init_unsat",   before.unsatisfied_edges);

        /* Dump the interference graph in Appel's format. */
        if (dump_flags & DUMP_APPEL) {
                FILE *f = my_open(cenv, "", ".apl");
                co_dump_appel_graph(co, f);
                fclose(f);
        }

        if (dump_flags & DUMP_BEFORE) {
                FILE *f = my_open(cenv, "", "-before.dot");
                co_dump_ifg_dot(co, f, style_flags);
                fclose(f);
        }

        /* if the algo can improve results, provide an initial solution with heur3 */
        if (improve && algos[algo].can_improve_existing) {
                co_complete_stats_t stats;

                /* produce a heuristic solution */
#ifdef WITH_JVM
                co_solve_heuristic_java(co);
#else
                co_solve_heuristic(co);
#endif /* WITH_JVM */

                /* do the stats and provide the current costs */
                co_complete_stats(co, &stats);
                be_stat_ev_ull("co_prepare_costs", stats.costs);
        }

#ifdef WITH_JVM
        /* start the JVM here so that it does not tamper the timing. */
        if (algo == CO_ALGO_HEUR3)
                be_java_coal_start_jvm();
#endif /* WITH_JVM */

        algo_func = algos[algo].algo;

        /* perform actual copy minimization */
        lc_timer_reset_and_start(timer);
        was_optimal = algo_func(co);
        lc_timer_stop(timer);

        be_stat_ev("co_time", lc_timer_elapsed_msec(timer));
        be_stat_ev_ull("co_optimal", was_optimal);

        if (dump_flags & DUMP_AFTER) {
                FILE *f = my_open(cenv, "", "-after.dot");
                co_dump_ifg_dot(co, f, style_flags);
                fclose(f);
        }

        co_complete_stats(co, &after);

        if (do_stats) {
                ulong64 optimizable_costs = after.max_costs - after.inevit_costs;
                ulong64 evitable          = after.costs     - after.inevit_costs;

                ir_printf("%30F ", cenv->irg);
                printf("%10s %10" ULL_FMT "%10" ULL_FMT "%10" ULL_FMT, cenv->cls->name, after.max_costs, before.costs, after.inevit_costs);

                if(optimizable_costs > 0)
                        printf("%10" ULL_FMT " %5.2f\n", after.costs, (evitable * 100.0) / optimizable_costs);
                else
                        printf("%10" ULL_FMT " %5s\n", after.costs, "-");
        }

        be_stat_ev_ull("co_after_costs", after.costs);
        be_stat_ev_ull("co_after_unsat", after.unsatisfied_edges);

        co_free_graph_structure(co);
        co_free_ou_structure(co);
        free_copy_opt(co);
}