another fehler
[libfirm] / ir / be / becopyheur4.c
index 266c7d9..6d170a7 100644 (file)
@@ -47,6 +47,9 @@
 #include "irprintf.h"
 #include "irbitset.h"
 #include "error.h"
+#include "list.h"
+
+#include "irbitset.h"
 
 #include "bearch.h"
 #include "beifg.h"
 #include "becopyopt_t.h"
 #include "bemodule.h"
 
-DEBUG_ONLY(static firm_dbg_module_t *dbg = NULL;)
 
 #define COL_COST_INFEASIBLE       DBL_MAX
 #define AFF_NEIGHBOUR_FIX_BENEFIT 128.0
 #define NEIGHBOUR_CONSTR_COSTS    64.0
 
-#define DBG_AFF_CHUNK(env, level, chunk) DEBUG_ONLY(do { if (firm_dbg_get_mask(dbg) & (level)) dbg_aff_chunk((env), (chunk)); } while(0))
-#define DBG_COL_COST(env, level, cost)   DEBUG_ONLY(do { if (firm_dbg_get_mask(dbg) & (level)) dbg_col_cost((env), (cost)); } while(0))
+
+#ifdef DEBUG_libfirm
+
+#define DBG_AFF_CHUNK(env, level, chunk) do { if (firm_dbg_get_mask(dbg) & (level)) dbg_aff_chunk((env), (chunk)); } while(0)
+#define DBG_COL_COST(env, level, cost)   do { if (firm_dbg_get_mask(dbg) & (level)) dbg_col_cost((env), (cost)); } while(0)
+
+static firm_dbg_module_t *dbg = NULL;
+
+#else
+
+#define DBG_AFF_CHUNK(env, level, chunk)
+#define DBG_COL_COST(env, level, cost)
+
+#endif
 
 static int last_chunk_id = 0;
+static int recolor_limit = 4;
 
 typedef struct _col_cost_t {
        int    col;
@@ -74,13 +89,14 @@ typedef struct _col_cost_t {
  * An affinity chunk.
  */
 typedef struct _aff_chunk_t {
-       ir_node  **n;                   /**< An ARR_F containing all nodes of the chunk. */
-       bitset_t *nodes;                /**< A bitset containing all nodes inside this chunk. */
-       bitset_t *interfere;            /**< A bitset containing all interfering neighbours of the nodes in this chunk. */
-       int      weight;                /**< Weight of this chunk */
-       unsigned weight_consistent : 1; /**< Set if the weight is consistent. */
-       unsigned deleted           : 1; /**< Set if the was deleted. */
-       int      id;                    /**< For debugging: An id of this chunk. */
+       ir_node    **n;                   /**< An ARR_F containing all nodes of the chunk. */
+       bitset_t   *nodes;                /**< A bitset containing all nodes inside this chunk. */
+       bitset_t   *interfere;            /**< A bitset containing all interfering neighbours of the nodes in this chunk. */
+       int        weight;                /**< Weight of this chunk */
+       unsigned   weight_consistent : 1; /**< Set if the weight is consistent. */
+       unsigned   deleted           : 1; /**< Set if the was deleted. */
+       int        id;                    /**< For debugging: An id of this chunk. */
+       col_cost_t *color_affinity;
 } aff_chunk_t;
 
 /**
@@ -107,17 +123,18 @@ typedef struct _co_mst_env_t {
 
 /* stores coalescing related information for a node */
 typedef struct _co_mst_irn_t {
-       ir_node     *irn;              /**< the irn this information belongs to */
-       aff_chunk_t *chunk;            /**< the chunk this irn belongs to */
-       bitset_t    *adm_colors;       /**< set of admissible colors for this irn */
-       ir_node     **int_neighs;      /**< array of all interfering neighbours (cached for speed reasons) */
-       int         n_neighs;          /**< length of the interfering neighbours array. */
-       int         int_aff_neigh;     /**< number of interfering affinity neighbours */
-       int         col;               /**< color currently assigned */
-       int         init_col;          /**< the initial color */
-       int         tmp_col;           /**< a temporary assigned color */
-       unsigned    fixed     : 1;     /**< the color is fixed */
-       unsigned    tmp_fixed : 1;     /**< the color is temporary fixed */
+       ir_node          *irn;              /**< the irn this information belongs to */
+       aff_chunk_t      *chunk;            /**< the chunk this irn belongs to */
+       bitset_t         *adm_colors;       /**< set of admissible colors for this irn */
+       ir_node          **int_neighs;      /**< array of all interfering neighbours (cached for speed reasons) */
+       int              n_neighs;          /**< length of the interfering neighbours array. */
+       int              int_aff_neigh;     /**< number of interfering affinity neighbours */
+       int              col;               /**< color currently assigned */
+       int              init_col;          /**< the initial color */
+       int              tmp_col;           /**< a temporary assigned color */
+       unsigned         fixed     : 1;     /**< the color is fixed */
+       struct list_head list;              /**< Queue for coloring undo. */
+       double           constr_factor;
 } co_mst_irn_t;
 
 #define get_co_mst_irn(mst_env, irn) (phase_get_or_set_irn_data(&(mst_env)->ph, (irn)))
@@ -172,7 +189,7 @@ static void dbg_col_cost(const co_mst_env_t *env, const col_cost_t *cost) {
 #endif /* DEBUG_libfirm */
 
 static INLINE int get_mst_irn_col(const co_mst_irn_t *node) {
-       return node->tmp_fixed ? node->tmp_col : node->col;
+       return node->tmp_col >= 0 ? node->tmp_col : node->col;
 }
 
 /**
@@ -217,8 +234,8 @@ static int cmp_aff_edge(const void *a, const void *b) {
 static int cmp_col_cost(const void *a, const void *b) {
        const col_cost_t *c1 = a;
        const col_cost_t *c2 = b;
-
-       return c1->cost < c2->cost ? -1 : 1;
+       double diff = c1->cost - c2->cost;
+       return (diff > 0) - (diff < 0);
 }
 
 /**
@@ -231,6 +248,7 @@ static INLINE aff_chunk_t *new_aff_chunk(co_mst_env_t *env) {
        c->n                 = NEW_ARR_F(ir_node *, 0);
        c->nodes             = bitset_irg_malloc(env->co->irg);
        c->interfere         = bitset_irg_malloc(env->co->irg);
+       c->color_affinity    = xmalloc(env->k * sizeof(c->color_affinity[0]));
        c->id                = last_chunk_id++;
        pset_insert(env->chunkset, c, c->id);
        return c;
@@ -243,6 +261,7 @@ static INLINE void delete_aff_chunk(co_mst_env_t *env, aff_chunk_t *c) {
        pset_remove(env->chunkset, c, c->id);
        bitset_free(c->nodes);
        bitset_free(c->interfere);
+       xfree(c->color_affinity);
        DEL_ARR_F(c->n);
        c->deleted = 1;
        free(c);
@@ -285,12 +304,12 @@ static void *co_mst_irn_init(ir_phase *ph, ir_node *irn, void *old) {
                res->irn           = irn;
                res->chunk         = NULL;
                res->fixed         = 0;
-               res->tmp_fixed     = 0;
                res->tmp_col       = -1;
                res->int_neighs    = NULL;
                res->int_aff_neigh = 0;
                res->col           = arch_register_get_index(arch_get_irn_register(env->aenv, irn));
                res->init_col      = res->col;
+               INIT_LIST_HEAD(&res->list);
 
                DB((dbg, LEVEL_4, "Creating phase info for %+F\n", irn));
 
@@ -299,8 +318,10 @@ static void *co_mst_irn_init(ir_phase *ph, ir_node *irn, void *old) {
 
                /* Exclude colors not assignable to the irn */
                req = arch_get_register_req(env->aenv, irn, -1);
-               if (arch_register_req_is(req, limited))
+               if (arch_register_req_is(req, limited)) {
                        rbitset_copy_to_bitset(req->limited, res->adm_colors);
+                       res->constr_factor = 1.0 - (double) bitset_popcnt(res->adm_colors) / env->k;
+               }
                else
                        bitset_set_all(res->adm_colors);
 
@@ -340,17 +361,12 @@ static INLINE int aff_chunk_interferes(co_mst_env_t *env, const aff_chunk_t *chu
  * @return 1 if there are interferences between nodes of c1 and c2, 0 otherwise.
  */
 static INLINE int aff_chunks_interfere(co_mst_env_t *env, const aff_chunk_t *c1, const aff_chunk_t *c2) {
-       bitset_t *tmp;
-
+       (void) env;
        if (c1 == c2)
                return 0;
 
        /* check if there is a node in c2 having an interfering neighbor in c1 */
-       tmp = bitset_alloca(get_irg_last_idx(env->co->irg));
-       tmp = bitset_copy(tmp, c1->interfere);
-       tmp = bitset_and(tmp, c2->nodes);
-
-       return bitset_popcnt(tmp) > 0;
+       return bitset_intersect(c1->interfere, c2->nodes);
 }
 
 /**
@@ -371,7 +387,7 @@ static int aff_chunk_absorb(co_mst_env_t *env, ir_node *src, ir_node *tgt) {
        aff_chunk_t *c1 = get_aff_chunk(env, src);
        aff_chunk_t *c2 = get_aff_chunk(env, tgt);
 
-       DEBUG_ONLY(
+#ifdef DEBUG_libfirm
                DB((dbg, LEVEL_4, "Attempt to let c1 (id %d): ", c1 ? c1->id : -1));
                if (c1) {
                        DBG_AFF_CHUNK(env, LEVEL_4, c1);
@@ -385,7 +401,7 @@ static int aff_chunk_absorb(co_mst_env_t *env, ir_node *src, ir_node *tgt) {
                        DB((dbg, LEVEL_4, "{%+F}", tgt));
                }
                DB((dbg, LEVEL_4, "\n"));
-       )
+#endif
 
        if (c1 == NULL) {
                if (c2 == NULL) {
@@ -448,14 +464,26 @@ absorbed:
 /**
  * Assures that the weight of the given chunk is consistent.
  */
-static void aff_chunk_assure_weight(const co_mst_env_t *env, aff_chunk_t *c) {
+static void aff_chunk_assure_weight(co_mst_env_t *env, aff_chunk_t *c) {
        if (! c->weight_consistent) {
                int w = 0;
-               int idx, len;
+               int idx, len, i;
+
+               for (i = 0; i < env->k; ++i) {
+                       c->color_affinity[i].col = i;
+                       c->color_affinity[i].cost = 0.0;
+               }
 
                for (idx = 0, len = ARR_LEN(c->n); idx < len; ++idx) {
-                       ir_node               *n  = c->n[idx];
-                       const affinity_node_t *an = get_affinity_info(env->co, n);
+                       ir_node               *n       = c->n[idx];
+                       const affinity_node_t *an      = get_affinity_info(env->co, n);
+                       co_mst_irn_t          *node    = get_co_mst_irn(env, n);
+
+                       if (node->constr_factor > 0.0) {
+                               bitset_pos_t col;
+                               bitset_foreach (node->adm_colors, col)
+                                       c->color_affinity[col].cost -= node->constr_factor;
+                       }
 
                        if (an != NULL) {
                                neighb_t *neigh;
@@ -561,6 +589,10 @@ static void build_affinity_chunks(co_mst_env_t *env) {
                                                affinity_node_t *am = get_affinity_info(env->co, m);
                                                n2->int_aff_neigh = count_interfering_aff_neighs(env, am);
                                        }
+                                       /*
+                                        * these weights are pure hackery ;-).
+                                        * It's not chriswue's fault but mine.
+                                        */
                                        edge.weight = (double)neigh->costs / (double)(1 + n1->int_aff_neigh + n2->int_aff_neigh);
                                        ARR_APP1(aff_edge_t, edges, edge);
                                }
@@ -608,6 +640,71 @@ static void build_affinity_chunks(co_mst_env_t *env) {
        DEL_ARR_F(edges);
 }
 
+static void chunk_order_nodes(co_mst_env_t *env, aff_chunk_t *chunk)
+{
+       pqueue *grow = new_pqueue();
+       int i;
+       int max_weight = 0;
+       ir_node *max_node = NULL;
+
+       for (i = ARR_LEN(chunk->n) - 1; i >= 0; i--) {
+               ir_node *irn        = chunk->n[i];
+               affinity_node_t *an = get_affinity_info(env->co, irn);
+               int w = 0;
+               neighb_t *neigh;
+
+               if (arch_irn_is(env->aenv, irn, ignore))
+                       continue;
+
+               if (an) {
+                       co_gs_foreach_neighb(an, neigh)
+                               w += neigh->costs;
+
+                       if (w > max_weight) {
+                               max_weight = w;
+                               max_node   = irn;
+                       }
+               }
+       }
+
+       if (max_node) {
+               bitset_t *visited = bitset_irg_malloc(env->co->irg);
+
+               for (i = ARR_LEN(chunk->n) - 1; i >= 0; --i)
+                       bitset_add_irn(visited, chunk->n[i]);
+
+               pqueue_put(grow, max_node, max_weight);
+               bitset_remv_irn(visited, max_node);
+               i = 0;
+               while (!pqueue_empty(grow)) {
+                       ir_node *irn = pqueue_get(grow);
+                       affinity_node_t *an = get_affinity_info(env->co, irn);
+                       neighb_t *neigh;
+
+                       if (arch_irn_is(env->aenv, irn, ignore))
+                               continue;
+
+                       assert(i <= ARR_LEN(chunk->n));
+                       chunk->n[i++] = irn;
+
+                       assert(an);
+
+                       /* build the affinity edges */
+                       co_gs_foreach_neighb(an, neigh) {
+                               co_mst_irn_t *node = get_co_mst_irn(env, neigh->irn);
+
+                               if (bitset_contains_irn(visited, node->irn)) {
+                                       pqueue_put(grow, neigh->irn, neigh->costs);
+                                       bitset_remv_irn(visited, node->irn);
+                               }
+                       }
+               }
+
+               del_pqueue(grow);
+               bitset_free(visited);
+       }
+}
+
 /**
  * Greedy collect affinity neighbours into thew new chunk @p chunk starting at node @p node.
  */
@@ -753,23 +850,52 @@ static INLINE void col_cost_init_single(co_mst_env_t *env, col_cost_t *cost, int
  * Resets the temporary fixed color of all nodes within wait queue @p nodes.
  * ATTENTION: the queue is empty after calling this function!
  */
-static INLINE void reject_coloring(waitq *nodes) {
+static INLINE void reject_coloring(struct list_head *nodes) {
+       co_mst_irn_t *n, *temp;
        DB((dbg, LEVEL_4, "\treject coloring for"));
-       while (! waitq_empty(nodes)) {
-               co_mst_irn_t *n = waitq_get(nodes);
+       list_for_each_entry_safe(co_mst_irn_t, n, temp, nodes, list) {
                DB((dbg, LEVEL_4, " %+F", n->irn));
-               n->tmp_fixed = 0;
+               assert(n->tmp_col >= 0);
+               n->tmp_col = -1;
+               list_del_init(&n->list);
        }
        DB((dbg, LEVEL_4, "\n"));
 }
 
+static INLINE void materialize_coloring(struct list_head *nodes) {
+       co_mst_irn_t *n, *temp;
+       list_for_each_entry_safe(co_mst_irn_t, n, temp, nodes, list) {
+               assert(n->tmp_col >= 0);
+               n->col     = n->tmp_col;
+               n->tmp_col = -1;
+               list_del_init(&n->list);
+       }
+}
+
+static INLINE void set_temp_color(co_mst_irn_t *node, int col, struct list_head *changed)
+{
+       assert(col >= 0);
+       assert(!node->fixed);
+       assert(node->tmp_col < 0);
+       assert(node->list.next == &node->list && node->list.prev == &node->list);
+
+       list_add_tail(&node->list, changed);
+       node->tmp_col = col;
+}
+
+static INLINE int is_loose(co_mst_irn_t *node)
+{
+       return !node->fixed && node->tmp_col < 0;
+}
+
 /**
  * Determines the costs for each color if it would be assigned to node @p node.
  */
 static void determine_color_costs(co_mst_env_t *env, co_mst_irn_t *node, col_cost_t *costs) {
        affinity_node_t *an = get_affinity_info(env->co, node->irn);
        neighb_t        *aff_neigh;
-       int             idx, i;
+       bitset_pos_t     idx;
+       int              i;
 
        col_cost_init(env, costs, 0.0);
 
@@ -788,7 +914,7 @@ static void determine_color_costs(co_mst_env_t *env, co_mst_irn_t *node, col_cos
                        c     = (double)aff_neigh->costs;
 
                        /* calculate costs for fixed affinity neighbours */
-                       if (neigh->tmp_fixed || neigh->fixed) {
+                       if (!is_loose(neigh)) {
                                int col = get_mst_irn_col(neigh);
                                costs[col].cost -= c * AFF_NEIGHBOUR_FIX_BENEFIT;
                        }
@@ -803,15 +929,13 @@ static void determine_color_costs(co_mst_env_t *env, co_mst_irn_t *node, col_cos
 
                int_neigh = node->int_neighs[i];
 
-               /* skip ignore nodes */
-               if (arch_irn_is(env->aenv, int_neigh, ignore))
-                       continue;
+    assert(!arch_irn_is(env->aenv, int_neigh, ignore));
 
                neigh   = get_co_mst_irn(env, int_neigh);
                col     = get_mst_irn_col(neigh);
                col_cnt = bitset_popcnt(neigh->adm_colors);
 
-               if (neigh->tmp_fixed || neigh->fixed) {
+               if (!is_loose(neigh)) {
                        /* colors of fixed interfering neighbours are infeasible */
                        costs[col].cost = COL_COST_INFEASIBLE;
                }
@@ -826,6 +950,8 @@ static void determine_color_costs(co_mst_env_t *env, co_mst_irn_t *node, col_cos
                                }
                        }
                }
+
+               DB((dbg, LEVEL_4, "\tneigh %+F, loose: %d, color: %d\n", int_neigh, is_loose(neigh), col));
        }
 
        /* set all not admissible colors to COL_COST_INFEASIBLE */
@@ -834,26 +960,25 @@ static void determine_color_costs(co_mst_env_t *env, co_mst_irn_t *node, col_cos
 }
 
 /* need forward declaration due to recursive call */
-static int recolor_nodes(co_mst_env_t *env, co_mst_irn_t *node, col_cost_t *costs, waitq *changed_ones);
+static int recolor_nodes(co_mst_env_t *env, co_mst_irn_t *node, col_cost_t *costs, struct list_head *changed_ones, int depth);
 
 /**
  * Tries to change node to a color but @p explude_col.
  * @return 1 if succeeded, 0 otherwise.
  */
-static int change_node_color_excluded(co_mst_env_t *env, co_mst_irn_t *node, int exclude_col, waitq *changed_ones) {
+static int change_node_color_excluded(co_mst_env_t *env, co_mst_irn_t *node, int exclude_col, struct list_head *changed_ones, int depth) {
        int col = get_mst_irn_col(node);
        int res = 0;
 
        /* neighbours has already a different color -> good, temporary fix it */
        if (col != exclude_col) {
-               node->tmp_fixed = 1;
-               node->tmp_col   = col;
-               waitq_put(changed_ones, node);
+               if (is_loose(node))
+                       set_temp_color(node, col, changed_ones);
                return 1;
        }
 
        /* The node has the color it should not have _and_ has not been visited yet. */
-       if (! (node->tmp_fixed || node->fixed)) {
+       if (is_loose(node)) {
                col_cost_t *costs = alloca(env->n_regs * sizeof(costs[0]));
 
                /* Get the costs for giving the node a specific color. */
@@ -866,7 +991,7 @@ static int change_node_color_excluded(co_mst_env_t *env, co_mst_irn_t *node, int
                qsort(costs, env->n_regs, sizeof(costs[0]), cmp_col_cost);
 
                /* Try recoloring the node using the color list. */
-               res = recolor_nodes(env, node, costs, changed_ones);
+               res = recolor_nodes(env, node, costs, changed_ones, depth + 1);
        }
 
        return res;
@@ -877,10 +1002,12 @@ static int change_node_color_excluded(co_mst_env_t *env, co_mst_irn_t *node, int
  * ATTENTION: Expect @p costs already sorted by increasing costs.
  * @return 1 if coloring could be applied, 0 otherwise.
  */
-static int recolor_nodes(co_mst_env_t *env, co_mst_irn_t *node, col_cost_t *costs, waitq *changed_ones) {
+static int recolor_nodes(co_mst_env_t *env, co_mst_irn_t *node, col_cost_t *costs, struct list_head *changed_ones, int depth) {
        int   i;
-       waitq *local_changed = new_waitq();
-       waitq *tmp           = new_waitq();
+       struct list_head local_changed;
+
+       if (depth >= recolor_limit)
+               return 0;
 
        DBG((dbg, LEVEL_1, "\tRecoloring %+F with color-costs", node->irn));
        DBG_COL_COST(env, LEVEL_1, costs);
@@ -893,21 +1020,15 @@ static int recolor_nodes(co_mst_env_t *env, co_mst_irn_t *node, col_cost_t *cost
 
                /* If the costs for that color (and all successive) are infinite, bail out we won't make it anyway. */
                if (costs[i].cost == COL_COST_INFEASIBLE) {
-                       node->tmp_fixed = 0;
-                       del_waitq(local_changed);
-                       del_waitq(tmp);
                        return 0;
                }
 
                /* Set the new color of the node and mark the node as temporarily fixed. */
-               assert(! node->tmp_fixed && "Node must not have been temporary fixed.");
-               node->tmp_fixed = 1;
-               node->tmp_col   = tgt_col;
+               assert(node->tmp_col < 0 && "Node must not have been temporary fixed.");
+               INIT_LIST_HEAD(&local_changed);
+               set_temp_color(node, tgt_col, &local_changed);
                DBG((dbg, LEVEL_4, "\tTemporary setting %+F to color %d\n", node->irn, tgt_col));
 
-               assert(waitq_empty(local_changed) && "Node queue should be empty here.");
-               waitq_put(local_changed, node);
-
                /* try to color all interfering neighbours with current color forbidden */
                for (j = 0; j < node->n_neighs; ++j) {
                        co_mst_irn_t *nn;
@@ -920,8 +1041,8 @@ static int recolor_nodes(co_mst_env_t *env, co_mst_irn_t *node, col_cost_t *cost
                                continue;
 
                        nn = get_co_mst_irn(env, neigh);
-                       DB((dbg, LEVEL_4, "\tHandling neighbour %+F, at position %d (fixed: %d, tmp_fixed: %d, tmp_col: %d, col: %d)\n",
-                               neigh, j, nn->fixed, nn->tmp_fixed, nn->tmp_col, nn->col));
+                       DB((dbg, LEVEL_4, "\tHandling neighbour %+F, at position %d (fixed: %d, tmp_col: %d, col: %d)\n",
+                               neigh, j, nn->fixed, nn->tmp_col, nn->col));
 
                        /*
                                Try to change the color of the neighbor and record all nodes which
@@ -931,13 +1052,9 @@ static int recolor_nodes(co_mst_env_t *env, co_mst_irn_t *node, col_cost_t *cost
                        */
                        if (get_mst_irn_col(nn) == tgt_col) {
                                /* try to color neighbour with tgt_col forbidden */
-                               neigh_ok = change_node_color_excluded(env, nn, tgt_col, tmp);
+                               neigh_ok = change_node_color_excluded(env, nn, tgt_col, &local_changed, depth + 1);
 
-                               /* join lists of changed nodes */
-                               while (! waitq_empty(tmp))
-                                       waitq_put(local_changed, waitq_get(tmp));
-
-                               if (! neigh_ok)
+                               if (!neigh_ok)
                                        break;
                        }
                }
@@ -948,20 +1065,15 @@ static int recolor_nodes(co_mst_env_t *env, co_mst_irn_t *node, col_cost_t *cost
                */
                if (neigh_ok) {
                        /* append the local_changed ones to global ones */
-                       while (! waitq_empty(local_changed))
-                               waitq_put(changed_ones, waitq_get(local_changed));
-                       del_waitq(local_changed);
-                       del_waitq(tmp);
+                       list_splice(&local_changed, changed_ones);
                        return 1;
                }
                else {
                        /* coloring of neighbours failed, so we try next color */
-                       reject_coloring(local_changed);
+                       reject_coloring(&local_changed);
                }
        }
 
-       del_waitq(local_changed);
-       del_waitq(tmp);
        return 0;
 }
 
@@ -969,17 +1081,14 @@ static int recolor_nodes(co_mst_env_t *env, co_mst_irn_t *node, col_cost_t *cost
  * Tries to bring node @p node and all it's neighbours to color @p tgt_col.
  * @return 1 if color @p col could be applied, 0 otherwise
  */
-static int change_node_color(co_mst_env_t *env, co_mst_irn_t *node, int tgt_col, waitq *changed_ones) {
+static int change_node_color(co_mst_env_t *env, co_mst_irn_t *node, int tgt_col, struct list_head *changed_ones, int depth) {
        int col = get_mst_irn_col(node);
 
        /* if node already has the target color -> good, temporary fix it */
        if (col == tgt_col) {
                DBG((dbg, LEVEL_4, "\t\tCNC: %+F has already color %d, fix temporary\n", node->irn, tgt_col));
-               if (! node->tmp_fixed) {
-                       node->tmp_fixed = 1;
-                       node->tmp_col   = tgt_col;
-                       waitq_put(changed_ones, node);
-               }
+               if (is_loose(node))
+                       set_temp_color(node, tgt_col, changed_ones);
                return 1;
        }
 
@@ -987,22 +1096,22 @@ static int change_node_color(co_mst_env_t *env, co_mst_irn_t *node, int tgt_col,
                Node has not yet a fixed color and target color is admissible
                -> try to recolor node and it's affinity neighbours
        */
-       if (! (node->fixed || node->tmp_fixed) && bitset_is_set(node->adm_colors, tgt_col)) {
+       if (is_loose(node) && bitset_is_set(node->adm_colors, tgt_col)) {
                col_cost_t *costs = alloca(env->n_regs * sizeof(costs[0]));
                int        res;
 
                col_cost_init_single(env, costs, tgt_col);
 
                DBG((dbg, LEVEL_4, "\t\tCNC: Attempt to recolor %+F ===>>\n", node->irn));
-               res = recolor_nodes(env, node, costs, changed_ones);
+               res = recolor_nodes(env, node, costs, changed_ones, depth);
                DBG((dbg, LEVEL_4, "\t\tCNC: <<=== Recoloring of %+F %s\n", node->irn, res ? "succeeded" : "failed"));
 
                return res;
        }
 
-       DEBUG_ONLY(
+#ifdef DEBUG_libfirm
                if (firm_dbg_get_mask(dbg) & LEVEL_4) {
-                       if (node->fixed || node->tmp_fixed)
+                       if (!is_loose(node))
                                DB((dbg, LEVEL_4, "\t\tCNC: %+F has already fixed color %d\n", node->irn, col));
                        else {
                                DB((dbg, LEVEL_4, "\t\tCNC: color %d not admissible for %+F (", tgt_col, node->irn));
@@ -1010,7 +1119,7 @@ static int change_node_color(co_mst_env_t *env, co_mst_irn_t *node, int tgt_col,
                                DB((dbg, LEVEL_4, ")\n"));
                        }
                }
-       )
+#endif
 
        return 0;
 }
@@ -1022,19 +1131,47 @@ static int change_node_color(co_mst_env_t *env, co_mst_irn_t *node, int tgt_col,
 static void color_aff_chunk(co_mst_env_t *env, aff_chunk_t *c) {
        aff_chunk_t *best_chunk   = NULL;
        int         best_color    = -1;
-       waitq       *changed_ones = new_waitq();
+       int         did_all       = 0;
        waitq       *tmp_chunks   = new_waitq();
        waitq       *best_starts  = NULL;
+       col_cost_t  *order        = alloca(env->k * sizeof(order[0]));
        bitset_t    *visited;
-       int         col, idx, len;
+       int         idx, len, i;
+       struct list_head changed_ones;
+       bitset_pos_t pos;
 
        DB((dbg, LEVEL_2, "fragmentizing chunk #%d", c->id));
        DBG_AFF_CHUNK(env, LEVEL_2, c);
        DB((dbg, LEVEL_2, "\n"));
 
+       /* compute color preference */
+       memcpy(order, c->color_affinity, env->k * sizeof(order[0]));
+
+       bitset_foreach (c->interfere, pos) {
+               ir_node      *n    = get_idx_irn(env->co->irg, pos);
+               co_mst_irn_t *node = get_co_mst_irn(env, n);
+               bitset_pos_t col;
+
+               if (node->constr_factor > 0.0 && is_loose(node)) {
+                       bitset_foreach (node->adm_colors, col)
+                               order[col].cost += node->constr_factor;
+               }
+       }
+
+       qsort(order, env->k, sizeof(order[0]), cmp_col_cost);
 
-       /* check which color is the "best" for the given chunk */
-       for (col = 0; col < env->n_regs; ++col) {
+       chunk_order_nodes(env, c);
+
+       /* check which color is the "best" for the given chunk.
+        * if we found a color which was ok for all nodes, we take it
+        * and do not look further. (see did_all flag usage below.)
+        * If we have many colors which fit all nodes it is hard to decide
+        * which one to take anyway.
+        * TODO Sebastian: Perhaps we should at all nodes and figure out
+        * a suitable color using costs as done above (determine_color_costs).
+        */
+       for (i = 0; i < env->k && !did_all; ++i) {
+               int         col = order[i].col;
                int         one_good     = 0;
                waitq       *good_starts = new_waitq();
                aff_chunk_t *local_best;
@@ -1045,11 +1182,16 @@ static void color_aff_chunk(co_mst_env_t *env, aff_chunk_t *c) {
 
                DB((dbg, LEVEL_3, "\ttrying color %d\n", col));
 
+               /* suppose we can color all nodes to the same color */
+               did_all = 1;
+
+               INIT_LIST_HEAD(&changed_ones);
+
                /* try to bring all nodes of given chunk to the current color. */
                for (idx = 0, len = ARR_LEN(c->n); idx < len; ++idx) {
                        ir_node      *irn  = c->n[idx];
                        co_mst_irn_t *node = get_co_mst_irn(env, irn);
-                       int          good  = 0;
+                       int          good;
 
                        assert(! node->fixed && "Node must not have a fixed color.");
                        DB((dbg, LEVEL_4, "\t\tBringing %+F from color %d to color %d ...\n", irn, node->col, col));
@@ -1058,17 +1200,22 @@ static void color_aff_chunk(co_mst_env_t *env, aff_chunk_t *c) {
                                The order of the colored nodes is important, so we record the successfully
                                colored ones in the order they appeared.
                        */
-                       good = change_node_color(env, node, col, changed_ones);
-                       if (good)
+                       good = change_node_color(env, node, col, &changed_ones, 0);
+                       if (good) {
                                waitq_put(good_starts, node);
+                       }
+
                        one_good |= good;
+                       did_all  &= good;
 
-                       DB((dbg, LEVEL_4, "\t\t... %+F attempt from %d to %d %s\n", irn, node->col, col, one_good ? "succeeded" : "failed"));
+                       DB((dbg, LEVEL_4, "\t\t... %+F attempt from %d to %d %s\n", irn, node->col, col, good ? "succeeded" : "failed"));
                }
 
                /* try next color when failed */
-               if (! one_good)
+               if (! one_good) {
+                       reject_coloring(&changed_ones);
                        continue;
+               }
 
                /* fragment the chunk according to the coloring */
                local_best = fragment_chunk(env, col, c, tmp_chunks);
@@ -1097,8 +1244,7 @@ static void color_aff_chunk(co_mst_env_t *env, aff_chunk_t *c) {
                        del_waitq(good_starts);
                }
 
-               /* reject the coloring and bring the coloring to the initial state */
-               reject_coloring(changed_ones);
+               reject_coloring(&changed_ones);
        }
 
        /* free all intermediate created chunks except best one */
@@ -1111,7 +1257,6 @@ static void color_aff_chunk(co_mst_env_t *env, aff_chunk_t *c) {
 
        /* return if coloring failed */
        if (! best_chunk) {
-               del_waitq(changed_ones);
                if (best_starts)
                        del_waitq(best_starts);
                return;
@@ -1121,39 +1266,20 @@ static void color_aff_chunk(co_mst_env_t *env, aff_chunk_t *c) {
        DBG_AFF_CHUNK(env, LEVEL_2, best_chunk);
        DB((dbg, LEVEL_2, "using color %d\n", best_color));
 
-       /* get the best fragment from the best list and color it */
-       while (! waitq_empty(best_starts)) {
-               co_mst_irn_t *node = waitq_get(best_starts);
-               int          res;
-
-               if (! bitset_is_set(best_chunk->nodes, get_irn_idx(node->irn)))
-                       continue;
-
-               res = change_node_color(env, node, best_color, changed_ones);
-               if (! res)
-                       panic("Color manifesting failed for %+F, color %d in chunk %d\n", node->irn, best_color, best_chunk->id);
-               node->fixed = 1;
-               node->chunk = best_chunk;
-       }
-       /* we colored the successful start nodes, now color the rest of the chunk */
+       INIT_LIST_HEAD(&changed_ones);
        for (idx = 0, len = ARR_LEN(best_chunk->n); idx < len; ++idx) {
                ir_node      *irn  = best_chunk->n[idx];
                co_mst_irn_t *node = get_co_mst_irn(env, irn);
-               int          res;
-
-               res = change_node_color(env, node, best_color, changed_ones);
-               if (! res)
-                       panic("Color manifesting failed for %+F, color %d in chunk %d\n", irn, best_color, best_chunk->id);
-               DB((dbg, LEVEL_4, "\tManifesting color %d for %+F, chunk #%d\n", best_color, irn, best_chunk->id));
-               node->fixed = 1;
-               node->chunk = best_chunk;
-       }
-
-       /* materialize colors on changed nodes */
-       while (! waitq_empty(changed_ones)) {
-               co_mst_irn_t *n = waitq_get(changed_ones);
-               n->tmp_fixed = 0;
-               n->col       = n->tmp_col;
+               int res;
+
+               /* bring the node to the color. */
+               DB((dbg, LEVEL_4, "\tManifesting color %d for %+F, chunk #%d\n", best_color, node->irn, best_chunk->id));
+               INIT_LIST_HEAD(&changed_ones);
+               res = change_node_color(env, node, best_color, &changed_ones, 0);
+               if (res) {
+                       materialize_coloring(&changed_ones);
+                       node->fixed = 1;
+               }
        }
 
        /* remove the nodes in best chunk from original chunk */
@@ -1195,7 +1321,6 @@ static void color_aff_chunk(co_mst_env_t *env, aff_chunk_t *c) {
        /* clear obsolete chunks and free some memory */
        delete_aff_chunk(env, best_chunk);
        bitset_free(visited);
-       del_waitq(changed_ones);
        if (best_starts)
                del_waitq(best_starts);
 }
@@ -1247,7 +1372,7 @@ int co_solve_heuristic_mst(copy_opt_t *co) {
                if (arch_irn_is(mst_env.aenv, irn, ignore))
                        continue;
 
-               assert(mirn->fixed && "Node should have fixed color");
+               // assert(mirn->fixed && "Node should have fixed color");
 
                /* skip nodes where color hasn't changed */
                if (mirn->init_col == mirn->col)
@@ -1266,7 +1391,20 @@ int co_solve_heuristic_mst(copy_opt_t *co) {
        return 0;
 }
 
+static const lc_opt_table_entry_t options[] = {
+       LC_OPT_ENT_INT      ("limit", "limit recoloring", &recolor_limit),
+       LC_OPT_LAST
+};
+
+
 void be_init_copyheur4(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_entry_t *heur4_grp = lc_opt_get_grp(co_grp, "heur4");
+
+       lc_opt_add_table(heur4_grp, options);
        FIRM_DBG_REGISTER(dbg, "firm.be.co.heur4");
 }