return 0;
[libfirm] / ir / be / becopyheur4.c
index 6d170a7..d08819f 100644 (file)
@@ -48,6 +48,7 @@
 #include "irbitset.h"
 #include "error.h"
 #include "list.h"
+#include "statev.h"
 
 #include "irbitset.h"
 
@@ -77,8 +78,9 @@ static firm_dbg_module_t *dbg = NULL;
 
 #endif
 
-static int last_chunk_id = 0;
-static int recolor_limit = 4;
+static int last_chunk_id        = 0;
+static int recolor_limit        = 4;
+static double dislike_influence = 0.1;
 
 typedef struct _col_cost_t {
        int    col;
@@ -96,6 +98,7 @@ typedef struct _aff_chunk_t {
        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. */
+       int        visited;
        col_cost_t *color_affinity;
 } aff_chunk_t;
 
@@ -119,6 +122,8 @@ typedef struct _co_mst_env_t {
        be_ifg_t         *ifg;           /**< the interference graph */
        const arch_env_t *aenv;          /**< the arch environment */
        copy_opt_t       *co;            /**< the copy opt object */
+       int               chunk_visited;
+       col_cost_t      **single_cols;
 } co_mst_env_t;
 
 /* stores coalescing related information for a node */
@@ -178,12 +183,8 @@ static void dbg_admissible_colors(const co_mst_env_t *env, const co_mst_irn_t *n
  */
 static void dbg_col_cost(const co_mst_env_t *env, const col_cost_t *cost) {
        int i;
-       for (i = 0; i < env->n_regs; ++i) {
-               if (cost[i].cost == COL_COST_INFEASIBLE)
-                       fprintf(stderr, " (%d, INF)", cost[i].col);
-               else
-                       fprintf(stderr, " (%d, %.1f)", cost[i].col, cost[i].cost);
-       }
+       for (i = 0; i < env->n_regs; ++i)
+               fprintf(stderr, " (%d, %.4f)", cost[i].col, cost[i].cost);
 }
 
 #endif /* DEBUG_libfirm */
@@ -231,13 +232,20 @@ static int cmp_aff_edge(const void *a, const void *b) {
 }
 
 /** compares to color-cost pairs */
-static int cmp_col_cost(const void *a, const void *b) {
+static __attribute__((unused)) int cmp_col_cost_lt(const void *a, const void *b) {
        const col_cost_t *c1 = a;
        const col_cost_t *c2 = b;
        double diff = c1->cost - c2->cost;
        return (diff > 0) - (diff < 0);
 }
 
+static int cmp_col_cost_gt(const void *a, const void *b) {
+       const col_cost_t *c1 = a;
+       const col_cost_t *c2 = b;
+       double diff = c2->cost - c1->cost;
+       return (diff > 0) - (diff < 0);
+}
+
 /**
  * Creates a new affinity chunk
  */
@@ -248,8 +256,9 @@ 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->color_affinity    = xmalloc(env->n_regs * sizeof(c->color_affinity[0]));
        c->id                = last_chunk_id++;
+       c->visited           = 0;
        pset_insert(env->chunkset, c, c->id);
        return c;
 }
@@ -295,7 +304,7 @@ static void *co_mst_irn_init(ir_phase *ph, ir_node *irn, void *old) {
        co_mst_irn_t *res = old ? old : phase_alloc(ph, sizeof(res[0]));
        co_mst_env_t *env = ph->priv;
 
-       if (res != old) {
+       if (!old) {
                const arch_register_req_t *req;
                void     *nodes_it = be_ifg_nodes_iter_alloca(env->ifg);
                ir_node  *neigh;
@@ -318,16 +327,17 @@ 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);
 
                /* exclude global ignore registers as well */
                bitset_andnot(res->adm_colors, env->ignore_regs);
 
+               /* compute the constraint factor */
+               res->constr_factor = (double) (1 + env->n_regs - bitset_popcnt(res->adm_colors)) / env->n_regs;
+
                /* set the number of interfering affinity neighbours to -1, they are calculated later */
                res->int_aff_neigh = -1;
 
@@ -436,17 +446,9 @@ static int aff_chunk_absorb(co_mst_env_t *env, ir_node *src, ir_node *tgt) {
        } else if (c1 != c2 && ! aff_chunks_interfere(env, c1, c2)) {
                int idx, len;
 
-               for (idx = 0, len = ARR_LEN(c2->n); idx < len; ++idx) {
-                       ir_node      *n  = c2->n[idx];
-                       co_mst_irn_t *mn = get_co_mst_irn(env, n);
+               for (idx = 0, len = ARR_LEN(c2->n); idx < len; ++idx)
+                       aff_chunk_add_node(c1, get_co_mst_irn(env, c2->n[idx]));
 
-                       mn->chunk = c1;
-
-                       if (! bitset_is_set(c1->nodes, get_irn_idx(n)))
-                               ARR_APP1(ir_node *, c1->n, n);
-               }
-
-               bitset_or(c1->nodes, c2->nodes);
                bitset_or(c1->interfere, c2->interfere);
                c1->weight_consistent = 0;
 
@@ -469,7 +471,7 @@ static void aff_chunk_assure_weight(co_mst_env_t *env, aff_chunk_t *c) {
                int w = 0;
                int idx, len, i;
 
-               for (i = 0; i < env->k; ++i) {
+               for (i = 0; i < env->n_regs; ++i) {
                        c->color_affinity[i].col = i;
                        c->color_affinity[i].cost = 0.0;
                }
@@ -479,10 +481,11 @@ static void aff_chunk_assure_weight(co_mst_env_t *env, aff_chunk_t *c) {
                        const affinity_node_t *an      = get_affinity_info(env->co, n);
                        co_mst_irn_t          *node    = get_co_mst_irn(env, n);
 
+                       node->chunk = c;
                        if (node->constr_factor > 0.0) {
                                bitset_pos_t col;
                                bitset_foreach (node->adm_colors, col)
-                                       c->color_affinity[col].cost -= node->constr_factor;
+                                       c->color_affinity[col].cost += node->constr_factor;
                        }
 
                        if (an != NULL) {
@@ -500,7 +503,11 @@ static void aff_chunk_assure_weight(co_mst_env_t *env, aff_chunk_t *c) {
                        }
                }
 
+               for (i = 0; i < env->n_regs; ++i)
+                       c->color_affinity[i].cost *= (1.0 / ARR_LEN(c->n));
+
                c->weight            = w;
+               // c->weight            = bitset_popcnt(c->nodes);
                c->weight_consistent = 1;
        }
 }
@@ -593,7 +600,7 @@ static void build_affinity_chunks(co_mst_env_t *env) {
                                         * 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);
+                                       edge.weight = neigh->costs;
                                        ARR_APP1(aff_edge_t, edges, edge);
                                }
                        }
@@ -640,7 +647,7 @@ 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)
+static __attribute__((unused)) void chunk_order_nodes(co_mst_env_t *env, aff_chunk_t *chunk)
 {
        pqueue *grow = new_pqueue();
        int i;
@@ -818,34 +825,6 @@ static aff_chunk_t *fragment_chunk(co_mst_env_t *env, int col, aff_chunk_t *c, w
        return best;
 }
 
-/**
- * Initializes an array of color-cost pairs.
- * Sets forbidden colors to costs COL_COST_INFEASIBLE and all others to @p c.
- */
-static INLINE void col_cost_init(co_mst_env_t *env, col_cost_t *cost, double c) {
-       int i;
-
-       for (i = 0; i < env->n_regs; ++i) {
-               cost[i].col = i;
-               if (bitset_is_set(env->ignore_regs, i))
-                       cost[i].cost = COL_COST_INFEASIBLE;
-               else
-                       cost[i].cost = c;
-       }
-}
-
-/**
- * Initializes an array of color-cost pairs.
- * Sets all colors except color @p col to COL_COST_INFEASIBLE and @p col to 0.0
- */
-static INLINE void col_cost_init_single(co_mst_env_t *env, col_cost_t *cost, int col) {
-       assert(! bitset_is_set(env->ignore_regs, col) && "Attempt to use forbidden color.");
-       col_cost_init(env, cost, COL_COST_INFEASIBLE);
-       cost[col].col = 0;
-       cost[0].col   = col;
-       cost[0].cost  = 0.0;
-}
-
 /**
  * Resets the temporary fixed color of all nodes within wait queue @p nodes.
  * ATTENTION: the queue is empty after calling this function!
@@ -878,6 +857,7 @@ static INLINE void set_temp_color(co_mst_irn_t *node, int col, struct list_head
        assert(!node->fixed);
        assert(node->tmp_col < 0);
        assert(node->list.next == &node->list && node->list.prev == &node->list);
+       assert(bitset_is_set(node->adm_colors, col));
 
        list_add_tail(&node->list, changed);
        node->tmp_col = col;
@@ -892,88 +872,51 @@ static INLINE int is_loose(co_mst_irn_t *node)
  * 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;
-       bitset_pos_t     idx;
-       int              i;
-
-       col_cost_init(env, costs, 0.0);
-
-       /* calculate (negative) costs for affinity neighbours */
-       if (an != NULL) {
-               co_gs_foreach_neighb(an, aff_neigh) {
-                       ir_node      *m = aff_neigh->irn;
-                       co_mst_irn_t *neigh;
-                       double       c;
-
-                       /* skip ignore nodes */
-                       if (arch_irn_is(env->aenv, m, ignore))
-                               continue;
-
-                       neigh = get_co_mst_irn(env, m);
-                       c     = (double)aff_neigh->costs;
+       int *neigh_cols = alloca(env->n_regs * sizeof(*neigh_cols));
+       int n_loose = 0;
+       double coeff;
+       int i;
 
-                       /* calculate costs for fixed affinity neighbours */
-                       if (!is_loose(neigh)) {
-                               int col = get_mst_irn_col(neigh);
-                               costs[col].cost -= c * AFF_NEIGHBOUR_FIX_BENEFIT;
-                       }
-               }
+       for (i = 0; i < env->n_regs; ++i) {
+               neigh_cols[i] = 0;
+               costs[i].col = i;
+               costs[i].cost = bitset_is_set(node->adm_colors, i) ? node->constr_factor : 0.0;
        }
 
-       /* calculate (positive) costs for interfering neighbours */
        for (i = 0; i < node->n_neighs; ++i) {
-               co_mst_irn_t *neigh;
-               int          col, col_cnt;
-               ir_node      *int_neigh;
-
-               int_neigh = node->int_neighs[i];
-
-    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 (!is_loose(neigh)) {
-                       /* colors of fixed interfering neighbours are infeasible */
-                       costs[col].cost = COL_COST_INFEASIBLE;
-               }
-               else if (col_cnt < env->k) {
-                       /* calculate costs for constrained interfering neighbours */
-                       double ratio = 1.0 - ((double)col_cnt / (double)env->k);
-
-                       bitset_foreach_clear(neigh->adm_colors, idx) {
-                               /* check only explicitly forbidden colors (skip global forbidden ones) */
-                               if (! bitset_is_set(env->ignore_regs, idx)) {
-                                       costs[col].cost += ratio * NEIGHBOUR_CONSTR_COSTS;
-                               }
-                       }
+               co_mst_irn_t *n = get_co_mst_irn(env, node->int_neighs[i]);
+               int col = get_mst_irn_col(n);
+               if (is_loose(n)) {
+                       ++n_loose;
+                       ++neigh_cols[col];
                }
 
-               DB((dbg, LEVEL_4, "\tneigh %+F, loose: %d, color: %d\n", int_neigh, is_loose(neigh), col));
+               else
+                       costs[col].cost = 0.0;
        }
 
-       /* set all not admissible colors to COL_COST_INFEASIBLE */
-       bitset_foreach_clear(node->adm_colors, idx)
-               costs[idx].cost = COL_COST_INFEASIBLE;
+       if (n_loose > 0) {
+               coeff = 1.0 / n_loose;
+               for (i = 0; i < env->n_regs; ++i)
+                       costs[i].cost *= 1.0 - coeff * neigh_cols[i];
+       }
 }
 
 /* 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, struct list_head *changed_ones, int depth);
+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 *max_depth, int *trip);
 
 /**
  * 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, struct list_head *changed_ones, int depth) {
+static int change_node_color_excluded(co_mst_env_t *env, co_mst_irn_t *node, int exclude_col, struct list_head *changed, int depth, int *max_depth, int *trip) {
        int col = get_mst_irn_col(node);
        int res = 0;
 
        /* neighbours has already a different color -> good, temporary fix it */
        if (col != exclude_col) {
                if (is_loose(node))
-                       set_temp_color(node, col, changed_ones);
+                       set_temp_color(node, col, changed);
                return 1;
        }
 
@@ -985,13 +928,13 @@ static int change_node_color_excluded(co_mst_env_t *env, co_mst_irn_t *node, int
                determine_color_costs(env, node, costs);
 
                /* Since the node must not have the not_col, set the costs for that color to "infinity" */
-               costs[exclude_col].cost = COL_COST_INFEASIBLE;
+               costs[exclude_col].cost = 0.0;
 
                /* sort the colors according costs, cheapest first. */
-               qsort(costs, env->n_regs, sizeof(costs[0]), cmp_col_cost);
+               qsort(costs, env->n_regs, sizeof(costs[0]), cmp_col_cost_gt);
 
                /* Try recoloring the node using the color list. */
-               res = recolor_nodes(env, node, costs, changed_ones, depth + 1);
+               res = recolor_nodes(env, node, costs, changed, depth + 1, max_depth, trip);
        }
 
        return res;
@@ -1002,16 +945,20 @@ 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, struct list_head *changed_ones, int depth) {
+static int recolor_nodes(co_mst_env_t *env, co_mst_irn_t *node, col_cost_t *costs, struct list_head *changed, int depth, int *max_depth, int *trip) {
        int   i;
        struct list_head local_changed;
 
+       ++*trip;
+       if (depth > *max_depth)
+               *max_depth = depth;
+
        if (depth >= recolor_limit)
                return 0;
 
-       DBG((dbg, LEVEL_1, "\tRecoloring %+F with color-costs", node->irn));
-       DBG_COL_COST(env, LEVEL_1, costs);
-       DB((dbg, LEVEL_1, "\n"));
+       DBG((dbg, LEVEL_4, "\tRecoloring %+F with color-costs", node->irn));
+       DBG_COL_COST(env, LEVEL_4, costs);
+       DB((dbg, LEVEL_4, "\n"));
 
        for (i = 0; i < env->n_regs; ++i) {
                int tgt_col  = costs[i].col;
@@ -1019,9 +966,8 @@ static int recolor_nodes(co_mst_env_t *env, co_mst_irn_t *node, col_cost_t *cost
                int j;
 
                /* 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) {
+               if (costs[i].cost == 0.0)
                        return 0;
-               }
 
                /* Set the new color of the node and mark the node as temporarily fixed. */
                assert(node->tmp_col < 0 && "Node must not have been temporary fixed.");
@@ -1052,7 +998,7 @@ 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, &local_changed, depth + 1);
+                               neigh_ok = change_node_color_excluded(env, nn, tgt_col, &local_changed, depth + 1, max_depth, trip);
 
                                if (!neigh_ok)
                                        break;
@@ -1065,7 +1011,7 @@ 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 */
-                       list_splice(&local_changed, changed_ones);
+                       list_splice(&local_changed, changed);
                        return 1;
                }
                else {
@@ -1081,14 +1027,14 @@ 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, struct list_head *changed_ones, int depth) {
+static int change_node_color(co_mst_env_t *env, co_mst_irn_t *node, int tgt_col, struct list_head *changed) {
        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 (is_loose(node))
-                       set_temp_color(node, tgt_col, changed_ones);
+                       set_temp_color(node, tgt_col, changed);
                return 1;
        }
 
@@ -1097,14 +1043,18 @@ static int change_node_color(co_mst_env_t *env, co_mst_irn_t *node, int tgt_col,
                -> try to recolor node and it's affinity neighbours
        */
        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_t *costs = env->single_cols[tgt_col];
+               int res, max_depth, trip;
 
-               col_cost_init_single(env, costs, tgt_col);
+               max_depth = 0;
+               trip      = 0;
 
                DBG((dbg, LEVEL_4, "\t\tCNC: Attempt to recolor %+F ===>>\n", node->irn));
-               res = recolor_nodes(env, node, costs, changed_ones, depth);
+               res = recolor_nodes(env, node, costs, changed, 0, &max_depth, &trip);
                DBG((dbg, LEVEL_4, "\t\tCNC: <<=== Recoloring of %+F %s\n", node->irn, res ? "succeeded" : "failed"));
+               stat_ev_int("heur4_recolor_depth_max", max_depth);
+               stat_ev_int("heur4_recolor_trip", trip);
+
 
                return res;
        }
@@ -1130,37 +1080,53 @@ 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         n_nodes       = ARR_LEN(c->n);
        int         best_color    = -1;
-       int         did_all       = 0;
+       int         n_int_chunks  = 0;
        waitq       *tmp_chunks   = new_waitq();
        waitq       *best_starts  = NULL;
-       col_cost_t  *order        = alloca(env->k * sizeof(order[0]));
+       col_cost_t  *order        = alloca(env->n_regs * sizeof(order[0]));
        bitset_t    *visited;
        int         idx, len, i;
-       struct list_head changed_ones;
+       struct list_head changed;
        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"));
 
+       stat_ev_ctx_push_fmt("heur4_color_chunk", "%d", c->id);
+
+       ++env->chunk_visited;
+
        /* compute color preference */
-       memcpy(order, c->color_affinity, env->k * sizeof(order[0]));
+       memset(order, 0, env->n_regs * 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;
+               aff_chunk_t *chunk = node->chunk;
 
-               if (node->constr_factor > 0.0 && is_loose(node)) {
-                       bitset_foreach (node->adm_colors, col)
-                               order[col].cost += node->constr_factor;
+               if (is_loose(node) && chunk && chunk->visited < env->chunk_visited && !chunk->deleted) {
+                       chunk->visited = env->chunk_visited;
+                       ++n_int_chunks;
+
+                       aff_chunk_assure_weight(env, chunk);
+                       for (i = 0; i < env->n_regs; ++i)
+                               order[i].cost += chunk->color_affinity[i].cost;
                }
        }
 
-       qsort(order, env->k, sizeof(order[0]), cmp_col_cost);
+       for (i = 0; i < env->n_regs; ++i) {
+               double dislike = n_int_chunks > 0 ? 1.0 - order[i].cost / n_int_chunks : 0.0;
+               order[i].col  = i;
+               order[i].cost = (1.0 - dislike_influence) * c->color_affinity[i].cost + dislike_influence * dislike;
+       }
+
+       qsort(order, env->n_regs, sizeof(order[0]), cmp_col_cost_gt);
 
-       chunk_order_nodes(env, c);
+       DBG_COL_COST(env, LEVEL_2, order);
+       DB((dbg, LEVEL_2, "\n"));
 
        /* check which color is the "best" for the given chunk.
         * if we found a color which was ok for all nodes, we take it
@@ -1170,28 +1136,25 @@ static void color_aff_chunk(co_mst_env_t *env, aff_chunk_t *c) {
         * 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) {
+       for (i = 0; i < env->k; ++i) {
                int         col = order[i].col;
-               int         one_good     = 0;
                waitq       *good_starts = new_waitq();
                aff_chunk_t *local_best;
+               int          n_succeeded;
 
                /* skip ignore colors */
                if (bitset_is_set(env->ignore_regs, col))
                        continue;
 
-               DB((dbg, LEVEL_3, "\ttrying color %d\n", col));
+               DB((dbg, LEVEL_2, "\ttrying color %d\n", col));
 
-               /* suppose we can color all nodes to the same color */
-               did_all = 1;
-
-               INIT_LIST_HEAD(&changed_ones);
+               n_succeeded = 0;
 
                /* 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;
+                       ir_node         *irn  = c->n[idx];
+                       co_mst_irn_t    *node = get_co_mst_irn(env, irn);
+                       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));
@@ -1200,22 +1163,32 @@ 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, 0);
+                       INIT_LIST_HEAD(&changed);
+                       stat_ev_tim_push();
+                       good = change_node_color(env, node, col, &changed);
+                       stat_ev_tim_pop("heur4_recolor");
                        if (good) {
                                waitq_put(good_starts, node);
+                               materialize_coloring(&changed);
+                               node->fixed = 1;
                        }
 
-                       one_good |= good;
-                       did_all  &= good;
+                       else
+                               reject_coloring(&changed);
 
+                       n_succeeded += good;
                        DB((dbg, LEVEL_4, "\t\t... %+F attempt from %d to %d %s\n", irn, node->col, col, good ? "succeeded" : "failed"));
                }
 
+               /* unfix all nodes */
+               for (idx = 0, len = ARR_LEN(c->n); idx < len; ++idx) {
+                       co_mst_irn_t *node = get_co_mst_irn(env, c->n[idx]);
+                       node->fixed = 0;
+               }
+
                /* try next color when failed */
-               if (! one_good) {
-                       reject_coloring(&changed_ones);
+               if (n_succeeded == 0)
                        continue;
-               }
 
                /* fragment the chunk according to the coloring */
                local_best = fragment_chunk(env, col, c, tmp_chunks);
@@ -1225,8 +1198,8 @@ static void color_aff_chunk(co_mst_env_t *env, aff_chunk_t *c) {
                if (local_best) {
                        aff_chunk_assure_weight(env, local_best);
 
-                       DB((dbg, LEVEL_4, "\t\tlocal best chunk (id %d) for color %d: ", local_best->id, col));
-                       DBG_AFF_CHUNK(env, LEVEL_4, local_best);
+                       DB((dbg, LEVEL_3, "\t\tlocal best chunk (id %d) for color %d: ", local_best->id, col));
+                       DBG_AFF_CHUNK(env, LEVEL_3, local_best);
 
                        if (! best_chunk || best_chunk->weight < local_best->weight) {
                                best_chunk = local_best;
@@ -1234,9 +1207,9 @@ static void color_aff_chunk(co_mst_env_t *env, aff_chunk_t *c) {
                                if (best_starts)
                                        del_waitq(best_starts);
                                best_starts = good_starts;
-                               DB((dbg, LEVEL_4, "\n\t\t... setting global best chunk (id %d), color %d\n", best_chunk->id, best_color));
+                               DB((dbg, LEVEL_3, "\n\t\t... setting global best chunk (id %d), color %d\n", best_chunk->id, best_color));
                        } else {
-                               DB((dbg, LEVEL_4, "\n\t\t... omitting, global best is better\n"));
+                               DB((dbg, LEVEL_3, "\n\t\t... omitting, global best is better\n"));
                                del_waitq(good_starts);
                        }
                }
@@ -1244,9 +1217,13 @@ static void color_aff_chunk(co_mst_env_t *env, aff_chunk_t *c) {
                        del_waitq(good_starts);
                }
 
-               reject_coloring(&changed_ones);
+               /* if all nodes were recolored, bail out */
+               if (n_succeeded == n_nodes)
+                       break;
        }
 
+       stat_ev_int("heur4_colors_tried", i);
+
        /* free all intermediate created chunks except best one */
        while (! waitq_empty(tmp_chunks)) {
                aff_chunk_t *tmp = waitq_get(tmp_chunks);
@@ -1266,7 +1243,6 @@ 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));
 
-       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);
@@ -1274,12 +1250,15 @@ static void color_aff_chunk(co_mst_env_t *env, aff_chunk_t *c) {
 
                /* 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);
+               INIT_LIST_HEAD(&changed);
+               stat_ev_tim_push();
+               res = change_node_color(env, node, best_color, &changed);
+               stat_ev_tim_pop("heur4_recolor");
                if (res) {
-                       materialize_coloring(&changed_ones);
+                       materialize_coloring(&changed);
                        node->fixed = 1;
                }
+               assert(list_empty(&changed));
        }
 
        /* remove the nodes in best chunk from original chunk */
@@ -1318,11 +1297,19 @@ static void color_aff_chunk(co_mst_env_t *env, aff_chunk_t *c) {
                }
        }
 
+       for (idx = 0, len = ARR_LEN(best_chunk->n); idx < len; ++idx) {
+               ir_node      *n  = best_chunk->n[idx];
+               co_mst_irn_t *nn = get_co_mst_irn(env, n);
+               nn->chunk = NULL;
+       }
+
        /* clear obsolete chunks and free some memory */
        delete_aff_chunk(env, best_chunk);
        bitset_free(visited);
        if (best_starts)
                del_waitq(best_starts);
+
+       stat_ev_ctx_pop("heur4_color_chunk");
 }
 
 /**
@@ -1331,29 +1318,48 @@ static void color_aff_chunk(co_mst_env_t *env, aff_chunk_t *c) {
 int co_solve_heuristic_mst(copy_opt_t *co) {
        unsigned     n_regs       = co->cls->n_regs;
        bitset_t     *ignore_regs = bitset_alloca(n_regs);
-       unsigned     k;
+       unsigned     i, j, k;
        ir_node      *irn;
        co_mst_env_t mst_env;
 
+       stat_ev_tim_push();
+
        /* init phase */
        phase_init(&mst_env.ph, "co_mst", co->irg, PHASE_DEFAULT_GROWTH, co_mst_irn_init, &mst_env);
 
        k = be_put_ignore_regs(co->cenv->birg, co->cls, ignore_regs);
        k = n_regs - k;
 
-       mst_env.n_regs      = n_regs;
-       mst_env.k           = k;
-       mst_env.chunks      = new_pqueue();
-       mst_env.co          = co;
-       mst_env.ignore_regs = ignore_regs;
-       mst_env.ifg         = co->cenv->ifg;
-       mst_env.aenv        = co->aenv;
-       mst_env.chunkset    = pset_new_ptr(512);
+       mst_env.n_regs        = n_regs;
+       mst_env.k             = k;
+       mst_env.chunks        = new_pqueue();
+       mst_env.co            = co;
+       mst_env.ignore_regs   = ignore_regs;
+       mst_env.ifg           = co->cenv->ifg;
+       mst_env.aenv          = co->aenv;
+       mst_env.chunkset      = pset_new_ptr(512);
+       mst_env.chunk_visited = 0;
+       mst_env.single_cols   = phase_alloc(&mst_env.ph, sizeof(*mst_env.single_cols) * n_regs);
+
+       for (i = 0; i < n_regs; ++i) {
+               col_cost_t *vec = phase_alloc(&mst_env.ph, sizeof(*vec) * n_regs);
+
+               mst_env.single_cols[i] = vec;
+               for (j = 0; j < n_regs; ++j) {
+                       vec[j].col  = j;
+                       vec[j].cost = 0.0;
+               }
+               vec[i].col  = 0;
+               vec[0].col  = i;
+               vec[0].cost = 1.0;
+       }
 
        DBG((dbg, LEVEL_1, "==== Coloring %+F, class %s ====\n", co->irg, co->cls->name));
 
        /* build affinity chunks */
+       stat_ev_tim_push();
        build_affinity_chunks(&mst_env);
+       stat_ev_tim_pop("heur4_initial_chunk");
 
        /* color chunks as long as there are some */
        while (! pqueue_empty(mst_env.chunks)) {
@@ -1388,11 +1394,14 @@ int co_solve_heuristic_mst(copy_opt_t *co) {
        phase_free(&mst_env.ph);
        del_pset(mst_env.chunkset);
 
+       stat_ev_tim_pop("heur4_total");
+
        return 0;
 }
 
 static const lc_opt_table_entry_t options[] = {
-       LC_OPT_ENT_INT      ("limit", "limit recoloring", &recolor_limit),
+       LC_OPT_ENT_INT      ("limit", "limit recoloring",  &recolor_limit),
+       LC_OPT_ENT_DBL      ("di",    "dislike influence", &dislike_influence),
        LC_OPT_LAST
 };