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/*
 * This file is part of libFirm.
 * Copyright (C) 2012 University of Karlsruhe.
 */

/**
 * @file
 * @brief       Copy minimization driver.
 * @author      Daniel Grund
 * @date        12.04.2005
 *
 * Main file for the optimization reducing the copies needed for:
 * - Phi coalescing
 * - Register-constrained nodes
 * - Two-address code instructions
 */
#include "becopyopt_t.h"

#include "bearch.h"
#include "bedump.h"
#include "beifg.h"
#include "beinsn_t.h"
#include "beirg.h"
#include "belive.h"
#include "bemodule.h"
#include "benode.h"
#include "debug.h"
#include "execfreq_t.h"
#include "irdump_t.h"
#include "iredges_t.h"
#include "irgwalk.h"
#include "irloop_t.h"
#include "irnode_t.h"
#include "irprintf.h"
#include "irprog.h"
#include "irtools.h"
#include "lc_opts.h"
#include "lc_opts_enum.h"
#include "panic.h"
#include "pmap.h"
#include "raw_bitset.h"
#include "statev_t.h"
#include "util.h"
#include "xmalloc.h"

#define MIS_HEUR_TRIGGER 8

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

#define list_entry_units(lh) list_entry(lh, unit_t, units)

/**
 * Statistics over a copy optimization module.
 */
typedef struct {
	unsigned long long aff_edges;            /**< number of affinity edges. */
	unsigned long long aff_nodes;            /**< number of nodes with incident affinity edges. */
	unsigned long long aff_int;              /**< number of affinity edges whose nodes also interfere. */
	unsigned long long inevit_costs;         /**< costs which cannot be evited (due to interfering affinities). */
	unsigned long long max_costs;            /**< all costs of the affinities. */
	unsigned long long costs;                /**< The costs of the current coloring. */
	unsigned long long unsatisfied_edges;    /**< The number of unequally colored affinity edges. */
} co_complete_stats_t;

/**
 * Flags for dumping the IFG.
 */
enum {
	CO_IFG_DUMP_COLORS = 1 << 0, /**< Dump the graph colored. */
	CO_IFG_DUMP_LABELS = 1 << 1, /**< Dump node/edge labels. */
	CO_IFG_DUMP_SHAPE  = 1 << 2, /**< Give constrained nodes special shapes. */
	CO_IFG_DUMP_CONSTR = 1 << 3, /**< Dump the node constraints in the label. */
};

DEBUG_ONLY(static firm_dbg_module_t *dbg = NULL;)

static int co_get_costs_loop_depth(const ir_node *root, int pos);
static int co_get_costs_exec_freq(const ir_node *root, int pos);
static int co_get_costs_all_one(const ir_node *root, int pos);

static unsigned   dump_flags  = 0;
static unsigned   style_flags = CO_IFG_DUMP_COLORS;
static bool       do_stats    = false;
static cost_fct_t cost_func   = co_get_costs_exec_freq;

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 }
};

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_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_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_LAST
};

static be_module_list_entry_t *copyopts = NULL;
static const co_algo_info *selected_copyopt = NULL;

void be_register_copyopt(const char *name, co_algo_info *copyopt)
{
	if (selected_copyopt == NULL)
		selected_copyopt = copyopt;
	be_add_module_to_list(&copyopts, name, copyopt);
}

BE_REGISTER_MODULE_CONSTRUCTOR(be_init_copyopt)
void be_init_copyopt(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_add_module_list_opt(co_grp, "algo", "select copy optimization algo",
	                       &copyopts, (void**) &selected_copyopt);
}

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

BE_REGISTER_MODULE_CONSTRUCTOR(be_init_copynone)
void be_init_copynone(void)
{
	static co_algo_info copyheur = {
		void_algo
	};

	be_register_copyopt("none", &copyheur);
}

static copy_opt_t *new_copy_opt(be_chordal_env_t *chordal_env, cost_fct_t get_costs)
{
	FIRM_DBG_REGISTER(dbg, "ir.be.copyopt");

	copy_opt_t *const co = XMALLOCZ(copy_opt_t);
	co->cenv      = chordal_env;
	co->irg       = chordal_env->irg;
	co->cls       = chordal_env->cls;
	co->get_costs = get_costs;
	return co;
}

static void free_copy_opt(copy_opt_t *co)
{
	free(co);
}

/**
 * Checks if a node is optimizable, viz. has something to do with coalescing
 * @param irn  The irn to check
 */
static bool co_is_optimizable_root(const ir_node *irn)
{
	arch_register_req_t const *const req = arch_get_irn_register_req(irn);
	if (req->ignore)
		return false;

	if (is_Phi(irn) || is_Perm_Proj(irn))
		return true;

	if (req->should_be_same != 0)
		return true;

	return false;
}

/**
 * Computes the costs of a copy according to loop depth
 * @param pos  the argument position of arg in the root arguments
 * @return     Must be >= 0 in all cases.
 */
static int co_get_costs_loop_depth(const ir_node *root, int pos)
{
	ir_node *block = get_nodes_block(root);
	if (is_Phi(root))
		block = get_Block_cfgpred_block(block, pos);

	ir_loop *loop = get_irn_loop(block);
	int cost;
	if (loop != NULL) {
		int d = get_loop_depth(loop);
		cost = d*d;
	} else {
		cost = 0;
	}
	return cost+1;
}

static ir_execfreq_int_factors factors;
/* Remember the graph that we computed the factors for. */
static ir_graph               *irg_for_factors;

/**
 * Computes the costs of a copy according to execution frequency
 * @param pos  the argument position of arg in the root arguments
 * @return Must be >= 0 in all cases.
 */
static int co_get_costs_exec_freq(const ir_node *root, int pos)
{
	ir_node *root_bl = get_nodes_block(root);
	ir_node *copy_bl
		= is_Phi(root) ? get_Block_cfgpred_block(root_bl, pos) : root_bl;
	int      res     = get_block_execfreq_int(&factors, copy_bl);

	/* don't allow values smaller than one. */
	return MAX(1, res);
}

/**
 * All costs equal 1. Using this will reduce the _number_ of copies.
 * @param co   The copy opt object.
 * @return Must be >= 0 in all cases.
 */
static int co_get_costs_all_one(const ir_node *root, int pos)
{
	(void)root;
	(void)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 *const ou)
{
	/* assign the nodes into two groups.
	 * safe: node has no interference, hence it is in every max stable set.
	 * unsafe: node has an interference */
	ir_node **safe         = ALLOCAN(ir_node*, ou->node_count - 1);
	int       safe_costs   = 0;
	int       safe_count   = 0;
	ir_node **unsafe       = ALLOCAN(ir_node*, ou->node_count - 1);
	int      *unsafe_costs = ALLOCAN(int,      ou->node_count - 1);
	int       unsafe_count = 0;
	for (int i=1; i<ou->node_count; ++i) {
		bool     is_safe = true;
		ir_node *i_node  = ou->nodes[i];
		for (int o=1; o<ou->node_count; ++o) {
			ir_node *o_node = ou->nodes[o];
			if (i_node == o_node)
				continue;
			if (be_values_interfere(i_node, o_node)) {
				unsafe_costs[unsafe_count] = ou->costs[i];
				unsafe[unsafe_count] = i_node;
				++unsafe_count;
				is_safe = false;
				break;
			}
		}
		if (is_safe) {
			safe_costs += ou->costs[i];
			safe[safe_count++] = i_node;
		}
	}

	/* now compute the best set out of the unsafe nodes*/
	int best_weight = 0;
	if (unsafe_count > MIS_HEUR_TRIGGER) {
		bitset_t *best = bitset_alloca(unsafe_count);
		/* Heuristic: Greedy trial and error form index 0 to unsafe_count-1 */
		for (int i=0; i<unsafe_count; ++i) {
			bitset_set(best, i);
			/* check if it is a stable set */
			for (int o=bitset_next_set(best, 0); o!=-1 && o<i; o=bitset_next_set(best, o+1))
				if (be_values_interfere(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 */
		bitset_t *curr = bitset_alloca(unsafe_count);
		bitset_set_all(curr);
		while (bitset_popcount(curr) != 0) {
			/* check if curr is a stable set */
			for (int i=bitset_next_set(curr, 0); i!=-1; i=bitset_next_set(curr, i+1))
				for (int 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 (be_values_interfere(unsafe[i], unsafe[o]))
						goto no_stable_set;

			/* if we arrive here, we have a stable set */
			/* compute the weight of the stable set*/
			int 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 free_unit(unit_t *unit)
{
	free(unit->nodes);
	free(unit->costs);
	free(unit);
}

static void co_collect_units(ir_node *irn, void *env)
{
	if (get_irn_mode(irn) == mode_T)
		return;
	copy_opt_t                *co  = (copy_opt_t*)env;
	const arch_register_req_t *req = arch_get_irn_register_req(irn);
	if (req->cls != co->cls)
		return;
	if (!co_is_optimizable_root(irn))
		return;

	/* Init a new unit */
	unit_t *unit = XMALLOCZ(unit_t);
	unit->node_count = 1;
	INIT_LIST_HEAD(&unit->queue);

	/* Phi with some/all of its arguments */
	if (is_Phi(irn)) {
		/* init */
		int const arity = get_irn_arity(irn);
		unit->nodes = XMALLOCN(ir_node*, arity + 1);
		unit->costs = XMALLOCN(int,      arity + 1);
		unit->nodes[0] = irn;

		/* fill */
		foreach_irn_in(irn, i, arg) {
			assert(arch_get_irn_register_req(arg)->cls == co->cls && "Argument not in same register class.");
			if (arg == irn)
				continue;
			if (be_values_interfere(irn, arg)) {
				unit->inevitable_costs += co->get_costs(irn, 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_ignore(arg))
				continue;

			/* Check if arg has occurred at a prior position in the arg/list */
			int arg_pos = 0;
			for (int 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(irn, i);
				unit->node_count++;
			} else { /* arg has occurred before in same phi */
				/* increase costs for existing arg */
				unit->costs[arg_pos] += co->get_costs(irn, i);
			}
		}
		unit->nodes = XREALLOC(unit->nodes, ir_node*, unit->node_count);
		unit->costs = XREALLOC(unit->costs, int,      unit->node_count);
	} else if (is_Perm_Proj(irn)) {
		/* Proj of a perm with corresponding arg */
		assert(!be_values_interfere(irn, get_Perm_src(irn)));
		unit->nodes      = XMALLOCN(ir_node*, 2);
		unit->costs      = XMALLOCN(int,      2);
		unit->node_count = 2;
		unit->nodes[0]   = irn;
		unit->nodes[1]   = get_Perm_src(irn);
		unit->costs[1]   = co->get_costs(irn, -1);
	} else if (req->should_be_same != 0) {
		/* Src == Tgt of a 2-addr-code instruction */
		const unsigned other = req->should_be_same;

		int count = 0;
		for (int i = 0; (1U << i) <= other; ++i) {
			if (other & (1U << i)) {
				ir_node *o = get_irn_n(skip_Proj(irn), i);
				if (arch_irn_is_ignore(o))
					continue;
				if (be_values_interfere(irn, o))
					continue;
				++count;
			}
		}

		if (count != 0) {
			int k = 0;
			++count;
			unit->nodes = XMALLOCN(ir_node*, count);
			unit->costs = XMALLOCN(int,      count);
			unit->node_count = count;
			unit->nodes[k++] = irn;

			for (int i = 0; 1U << i <= other; ++i) {
				if (other & (1U << i)) {
					ir_node *o = get_irn_n(skip_Proj(irn), i);
					if (!arch_irn_is_ignore(o) &&
					    !be_values_interfere(irn, o)) {
						unit->nodes[k] = o;
						unit->costs[k] = co->get_costs(irn, -1);
						++k;
					}
				}
			}
		}
	} else {
		panic("this is not an optimizable node");
	}

	/* Insert the new unit at a position according to its costs */
	if (unit->node_count > 1) {
		/* Determine the maximum costs this unit can cause: all_nodes_cost */
		for (int 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 */
		struct list_head *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(unit);
	}
}

static 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);
}

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

int co_get_inevit_copy_costs(const copy_opt_t *co)
{
	ASSERT_OU_AVAIL(co);

	int res = 0;
	list_for_each_entry(unit_t, curr, &co->units, units)
		res += curr->inevitable_costs;
	return res;
}

int co_get_lower_bound(const copy_opt_t *co)
{
	ASSERT_OU_AVAIL(co);

	int res = 0;
	list_for_each_entry(unit_t, curr, &co->units, units)
		res += curr->inevitable_costs + curr->min_nodes_costs;
	return res;
}

static void co_complete_stats(const copy_opt_t *co, co_complete_stats_t *stat)
{
	bitset_t *seen = bitset_malloc(get_irg_last_idx(co->irg));

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

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

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

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

	free(seen);
}

static int compare_affinity_node_t(const void *k1, const void *k2, size_t size)
{
	(void)size;
	const affinity_node_t *n1 = (const affinity_node_t*)k1;
	const affinity_node_t *n2 = (const affinity_node_t*)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;
	new_node.irn        = n1;
	new_node.neighbours = NULL;
	affinity_node_t *node = set_insert(affinity_node_t, co->nodes, &new_node,
	                                   sizeof(new_node), hash_irn(new_node.irn));

	neighb_t *nbr;
	bool      allocnew = true;
	for (nbr = node->neighbours; nbr; nbr = nbr->next) {
		if (nbr->irn == n2) {
			allocnew = false;
			break;
		}
	}

	/* if we did not find n2 in n1's neighbourhood insert it */
	if (allocnew) {
		nbr        = OALLOC(&co->obst, neighb_t);
		nbr->irn   = n2;
		nbr->costs = 0;
		nbr->next  = node->neighbours;

		node->neighbours = nbr;
	}

	/* 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 (n1 != n2 && !be_values_interfere(n1, n2)) {
		add_edge(co, n1, n2, costs);
		add_edge(co, n2, n1, costs);
	}
}

static void build_graph_walker(ir_node *irn, void *env)
{
	if (get_irn_mode(irn) == mode_T)
		return;
	copy_opt_t                *co  = (copy_opt_t*)env;
	const arch_register_req_t *req = arch_get_irn_register_req(irn);
	if (req->cls != co->cls || req->ignore)
		return;

	if (is_Phi(irn)) { /* Phis */
		foreach_irn_in(irn, pos, arg) {
			add_edges(co, irn, arg, co->get_costs(irn, pos));
		}
	} else if (is_Perm_Proj(irn)) { /* Perms */
		ir_node *arg = get_Perm_src(irn);
		add_edges(co, irn, arg, co->get_costs(irn, -1));
	} else if (req->should_be_same != 0) {
		const unsigned other = req->should_be_same;
		for (int i = 0; 1U << i <= other; ++i) {
			if (other & (1U << i)) {
				ir_node *other = get_irn_n(skip_Proj(irn), i);
				if (!arch_irn_is_ignore(other))
					add_edges(co, irn, other, co->get_costs(irn, -1));
			}
		}
	}
}

/**
 * Constructs another internal representation of the affinity edges
 */
static 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);
}

/**
 * Frees the space used by the graph representation.
 * Does NOT free the whole copyopt structure
 */
static 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;
}

bool co_gs_is_optimizable(copy_opt_t const *const co, ir_node *const irn)
{
	ASSERT_GS_AVAIL(co);

	affinity_node_t new_node;
	new_node.irn = irn;
	affinity_node_t *n = set_find(affinity_node_t, co->nodes, &new_node,
	                              sizeof(new_node), hash_irn(new_node.irn));
	return n && n->neighbours;
}

static bool co_dump_appel_disjoint_constraints(ir_node *const a, ir_node *const b)
{
	arch_register_req_t const *const reqa = arch_get_irn_register_req(a);
	if (reqa->limited == NULL)
		return false;

	arch_register_req_t const *const reqb = arch_get_irn_register_req(b);
	if (reqb->limited == NULL)
		return false;

	return !rbitsets_have_common(reqa->limited, reqb->limited, reqa->cls->n_regs);
}

/**
 * Dump the interference graph according to the Appel/George coalescing contest file format.
 * See: http://www.cs.princeton.edu/~appel/coalesce/format.html
 * @note Requires graph structure.
 * @param co The copy opt object.
 * @param f  A file to dump to.
 */
static void co_dump_appel_graph(const copy_opt_t *co, FILE *f)
{
	be_ifg_t *ifg       = co->cenv->ifg;
	int      *color_map = ALLOCAN(int, co->cls->n_regs);
	int      *node_map  = XMALLOCN(int, get_irg_last_idx(co->irg) + 1);
	ir_graph *irg       = co->irg;
	be_irg_t *birg      = be_birg_from_irg(irg);

	unsigned n_regs = 0;
	for (unsigned i = 0; i < co->cls->n_regs; ++i) {
		const arch_register_t *reg = &co->cls->regs[i];
		if (rbitset_is_set(birg->allocatable_regs, reg->global_index)) {
			color_map[i] = n_regs++;
		} else {
			color_map[i] = -1;
		}
	}

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

	unsigned n = n_regs;
	be_ifg_foreach_node(ifg, irn) {
		if (arch_irn_is_ignore(irn))
			continue;
		node_map[get_irn_idx(irn)] = n++;
	}

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

	be_ifg_foreach_node(ifg, irn) {
		arch_register_req_t const *const req = arch_get_irn_register_req(irn);
		if (req->ignore)
			continue;

		int              idx = node_map[get_irn_idx(irn)];
		affinity_node_t *a   = get_affinity_info(co, irn);

		if (req->limited != NULL) {
			for (unsigned 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);
			}
		}

		neighbours_iter_t nit;
		be_ifg_foreach_neighbour(ifg, &nit, irn, adj) {
			if (!arch_irn_is_ignore(adj)
			    && !co_dump_appel_disjoint_constraints(irn, adj)) {
				int adj_idx = node_map[get_irn_idx(adj)];
				if (idx < adj_idx)
					fprintf(f, "%d %d -1\n", idx, adj_idx);
			}
		}

		if (a) {
			co_gs_foreach_neighb(a, n) {
				if (!arch_irn_is_ignore(n->irn)) {
					int n_idx = node_map[get_irn_idx(n->irn)];
					if (idx < n_idx)
						fprintf(f, "%d %d %d\n", idx, n_idx, (int) n->costs);
				}
			}
		}
	}

	free(node_map);
}

static FILE *my_open(const be_chordal_env_t *env, const char *prefix,
                     const char *suffix)
{
	const char *cup_name = be_get_irg_main_env(env->irg)->cup_name;
	size_t      n        = strlen(cup_name);
	char       *tu_name  = XMALLOCN(char, n + 1);
	strcpy(tu_name, cup_name);
	for (size_t i = 0; i < n; ++i) {
		if (tu_name[i] == '.')
			tu_name[i] = '_';
	}


	char buf[1024];
	ir_snprintf(buf, sizeof(buf), "%s%s_%F_%s%s", prefix, tu_name, env->irg,
	            env->cls->name, suffix);
	free(tu_name);
	FILE *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)
{
	ir_timer_t *timer = ir_timer_new();

	/* skip copymin if algo is 'none' */
	if (selected_copyopt->copyopt == void_algo)
		return;

	if (cost_func == co_get_costs_exec_freq && irg_for_factors != cenv->irg) {
		ir_calculate_execfreq_int_factors(&factors, cenv->irg);
		irg_for_factors = cenv->irg;
	}

	be_assure_live_chk(cenv->irg);

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

	co_complete_stats_t before;
	co_complete_stats(co, &before);

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

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

	if (dump_flags & DUMP_BEFORE) {
		FILE *f = my_open(cenv, "", "-before.vcg");
		be_dump_ifg_co(f, co, style_flags & CO_IFG_DUMP_LABELS, style_flags & CO_IFG_DUMP_COLORS);
		fclose(f);
	}

	/* perform actual copy minimization */
	ir_timer_reset_and_start(timer);
	int was_optimal = selected_copyopt->copyopt(co);
	ir_timer_stop(timer);

	stat_ev_dbl("co_time", ir_timer_elapsed_msec(timer));
	stat_ev_ull("co_optimal", was_optimal);
	ir_timer_free(timer);

	if (dump_flags & DUMP_AFTER) {
		FILE *f = my_open(cenv, "", "-after.vcg");
		be_dump_ifg_co(f, co, style_flags & CO_IFG_DUMP_LABELS, style_flags & CO_IFG_DUMP_COLORS);
		fclose(f);
	}

	co_complete_stats_t after;
	co_complete_stats(co, &after);

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

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

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

	/* Dump the interference graph in Appel's format. */
	if (dump_flags & DUMP_APPEL) {
		FILE *f = my_open(cenv, "", ".apl");
		fprintf(f, "# %llu %llu\n", after.costs, after.unsatisfied_edges);
		co_dump_appel_graph(co, f);
		fclose(f);
	}

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

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