changed handle_proj callback
[libfirm] / ir / be / bechordal.c
index 567fbca..a84ff8c 100644 (file)
 #include "config.h"
 #endif
 
+#ifdef HAVE_MALLOC_H
+#include <malloc.h>
+#endif
+
+#ifdef HAVE_ALLOCA_H
+#include <alloca.h>
+#endif
+
 #include <ctype.h>
 
 #include "obst.h"
+#include "pset.h"
 #include "list.h"
 #include "bitset.h"
 #include "iterator.h"
 #include "benumb_t.h"
 #include "besched_t.h"
 #include "belive_t.h"
+#include "benode_t.h"
 #include "bearch.h"
+#include "beifg.h"
 
 #include "bechordal_t.h"
 #include "bechordal_draw.h"
 
+#define DBG_LEVEL SET_LEVEL_0
+#define DBG_LEVEL_CHECK SET_LEVEL_0
+
 #define NO_COLOR (-1)
 
-#undef DUMP_INTERVALS
-#undef DUMP_PRESSURE
-#undef DUMP_IFG
+#define DUMP_INTERVALS
 
-#if defined(DUMP_IFG) && !defined(BUILD_GRAPH)
-#error Must define BUILD_GRAPH to be able to dump it.
-#endif
+typedef struct _be_chordal_alloc_env_t {
+       be_chordal_env_t *chordal_env;
 
+       pset *pre_colored;    /**< Set of precolored nodes. */
+       bitset_t *live;                         /**< A liveness bitset. */
+       bitset_t *colors;                       /**< The color mask. */
+       bitset_t *in_colors;        /**< Colors used by live in values. */
+       int colors_n;               /**< The number of colors. */
+} be_chordal_alloc_env_t;
 
-#ifdef DEBUG_libfirm
 #include "fourcc.h"
 
 /* Make a fourcc for border checking. */
 #define BORDER_FOURCC                          FOURCC('B', 'O', 'R', 'D')
 
-#endif /* DEBUG_libfirm */
-
-static firm_dbg_module_t *dbg;
-
-#ifdef BUILD_GRAPH
-
-#define IF_EDGE_HASH(e) ((e)->src)
-#define IF_NODE_HASH(n) ((n)->nnr)
-
-static int if_edge_cmp(const void *p1, const void *p2, size_t size)
+static void check_border_list(struct list_head *head)
 {
-       const if_edge_t *e1 = p1;
-       const if_edge_t *e2 = p2;
-
-       return !(e1->src == e2->src && e1->tgt == e2->tgt);
+  border_t *x;
+  list_for_each_entry(border_t, x, head, list) {
+    assert(x->magic == BORDER_FOURCC);
+  }
 }
 
-static int if_node_cmp(const void *p1, const void *p2, size_t size)
+static void check_heads(be_chordal_env_t *env)
 {
-       const if_node_t *n1 = p1;
-       const if_node_t *n2 = p2;
-
-       return n1->nnr != n2->nnr;
+  pmap_entry *ent;
+  for(ent = pmap_first(env->border_heads); ent; ent = pmap_next(env->border_heads)) {
+    /* ir_printf("checking border list of block %+F\n", ent->key); */
+    check_border_list(ent->value);
+  }
 }
 
-static INLINE if_edge_t *edge_init(if_edge_t *edge, int src, int tgt)
-{
-       /* Bring the smaller entry to src. */
-       if(src > tgt) {
-               edge->src = tgt;
-               edge->tgt = src;
-       } else {
-               edge->src = src;
-               edge->tgt = tgt;
-       }
-
-       return edge;
-}
-
-static INLINE void add_if(const be_chordal_env_t *env, int src, int tgt)
-{
-       if_edge_t edge;
-       if_node_t node, *src_node, *tgt_node;
-       /* insert edge */
-       edge_init(&edge, src, tgt);
-       set_insert(env->edges, &edge, sizeof(edge), IF_EDGE_HASH(&edge));
-
-       /* insert nodes */
-       node.nnr = src;
-       node.neighb = pset_new_ptr(8);
-       src_node = set_insert(env->nodes, &node, sizeof(node), IF_NODE_HASH(&node));
-       node.nnr = tgt;
-       node.neighb = pset_new_ptr(8);
-       tgt_node = set_insert(env->nodes, &node, sizeof(node), IF_NODE_HASH(&node));
-
-       /* insert neighbors into nodes */
-       pset_insert_ptr(src_node->neighb, tgt_node);
-       pset_insert_ptr(tgt_node->neighb, src_node);
-}
-
-static INLINE int are_connected(const be_chordal_env_t *env, int src, int tgt)
-{
-       if_edge_t edge;
-       edge_init(&edge, src, tgt);
-       return set_find(env->edges, &edge, sizeof(edge), IF_EDGE_HASH(&edge)) != NULL;
-}
-
-int ifg_has_edge(const be_chordal_env_t *env, const if_node_t *n1, const if_node_t* n2) {
-       return are_connected(env, n1->nnr, n2->nnr);
-}
-
-#ifdef DUMP_IFG
-
-static void dump_ifg(const be_chordal_env_t *env)
-{
-       static const char *colors[] = {
-               "coral",
-               "azure",
-               "bisque",
-               "aliceblue",
-               "blanchedalmond",
-               "deeppink",
-               "cornsilk",
-               "blueviolet",
-               "floralwhite",
-               "hotpink",
-               "gainsboro",
-               "indianred",
-               "cornflowerblue",
-               "ghostwhite",
-               "lightpink",
-               "palegoldenrod",
-               "darkslateblue",
-               "honeydew",
-               "ivory",
-               "lavender",
-               "mediumvioletred",
-               "indigo",
-               "lavenderblush",
-               "lemonchiffon",
-               "linen",
-               "pink",
-               "mintcream",
-               "red",
-               "mediumblue",
-               "mistyrose",
-               "mediumslateblue",
-               "moccasin",
-               "tomato",
-               "forestgreen",
-               "midnightblue",
-               "navajowhite",
-               "navy",
-               "oldlace",
-               "greenyellow",
-               "navyblue",
-               "papayawhip",
-               "lawngreen",
-               "powderblue",
-               "peachpuff",
-               "seashell",
-               "snow",
-               "thistle",
-               "wheat",
-               "darkkhaki",
-               "mintcream",
-               "khaki",
-               "Magentas",
-               "whitesmoke",
-               "peru",
-               "palegreen",
-               "blueviolet",
-               "rosybrown",
-               "saddlebrown",
-               "springgreen",
-               "darkviolet",
-               "darkslategray",
-               "dimgray",
-               "sienna",
-               "gray",
-               "tan",
-               "gray",
-               "mediumvioletred",
-               "lightgray",
-               "Oranges",
-               "cyan",
-               "lightslategray",
-               "darkorange",
-               "slategray",
-               "orangered",
-               "mediumturquoise",
-               "violet",
-               "paleturquoise"
-       };
-
-       static const int n_colors = sizeof(colors) / sizeof(colors[0]);
-
-       FILE *f;
-  set *edges = env->edges;
-  ir_graph *irg = env->irg;
-  char filename[128];
-
-  ir_snprintf(filename, sizeof(filename), "ifg_%s_%F.dot", env->cls->name, irg);
-
-       if((f = fopen(filename, "wt")) != NULL) {
-               bitset_pos_t pos;
-               int n_edges = 0;
-               if_edge_t *edge;
-               bitset_t *bs = bitset_malloc(get_graph_node_count(irg));
-
-               ir_fprintf(f, "graph \"%F\" {\n", irg);
-               fprintf(f, "\tnode [shape=box,style=filled]\n");
-
-               for(edge = set_first(edges); edge; edge = set_next(edges)) {
-                       bitset_set(bs, edge->src);
-                       bitset_set(bs, edge->tgt);
-                       n_edges++;
-               }
-
-               fprintf(f, "\tx [label=\"nodes: %u, edges: %d\"]\n", bitset_popcnt(bs), n_edges);
-
-               bitset_foreach(bs, pos) {
-                       int nr = (int) pos;
-                       ir_node *irn = get_irn_for_graph_nr(irg, nr);
-                       int color = get_irn_color(irn);
-
-                       ir_fprintf(f, "\tn%d [label=\"%n\",color=\"%s\"]\n", nr, irn,
-                                       color >= 0 && color < n_colors ? colors[color] : "black");
-               }
-
-               for(edge = set_first(edges); edge; edge = set_next(edges)) {
-                       fprintf(f, "\tn%d -- n%d [len=5]\n", edge->src, edge->tgt);
-               }
-
-               fprintf(f, "}\n");
-               fclose(f);
-
-               bitset_free(bs);
-       }
-
-}
-
-#endif /* DUMP_IFG */
-
-#endif /* BUILD_GRAPH */
-
 
 /**
  * Add an interval border to the list of a block's list
@@ -286,6 +113,7 @@ static INLINE border_t *border_add(be_chordal_env_t *env, struct list_head *head
 
                /* also allocate the def and tie it to the use. */
                def = obstack_alloc(&env->obst, sizeof(*def));
+               memset(def, 0, sizeof(*def));
                b->other_end = def;
                def->other_end = b;
 
@@ -296,10 +124,8 @@ static INLINE border_t *border_add(be_chordal_env_t *env, struct list_head *head
                 */
                set_irn_link(irn, def);
 
-#ifdef DEBUG_libfirm
                b->magic = BORDER_FOURCC;
                def->magic = BORDER_FOURCC;
-#endif
        }
 
        /*
@@ -310,9 +136,7 @@ static INLINE border_t *border_add(be_chordal_env_t *env, struct list_head *head
        else {
                b = get_irn_link(irn);
 
-#ifdef DEBUG_libfirm
                assert(b && b->magic == BORDER_FOURCC && "Illegal border encountered");
-#endif
        }
 
        b->pressure = pressure;
@@ -321,12 +145,209 @@ static INLINE border_t *border_add(be_chordal_env_t *env, struct list_head *head
        b->irn = irn;
        b->step = step;
        list_add_tail(&b->list, head);
-       DBG((dbg, LEVEL_5, "\t\t%s adding %n, step: %d\n",
-                               is_def ? "def" : "use", irn, step));
+       DBG((env->dbg, LEVEL_5, "\t\t%s adding %+F, step: %d\n", is_def ? "def" : "use", irn, step));
+
 
        return b;
 }
 
+/**
+ * Check, if an irn is of the register class currently under processing.
+ * @param env The chordal environment.
+ * @param irn The node.
+ * @return 1, if the node is of that register class, 0 if not.
+ */
+static INLINE int has_reg_class(const be_chordal_env_t *env, const ir_node *irn)
+{
+  return arch_irn_has_reg_class(env->main_env->arch_env, irn, -1, env->cls);
+}
+
+#define has_limited_constr(req, irn) \
+       (arch_get_register_req(arch_env, (req), irn, -1) && (req)->type == arch_register_req_type_limited)
+
+static int try_pre_color(be_chordal_env_t *env, ir_node *irn,
+                                                pset *pre_colored, bitset_t *colors_used)
+{
+       arch_register_req_t req;
+
+       if(arch_get_register_req(env->main_env->arch_env, &req, irn, -1) && arch_register_req_is(&req, limited)) {
+
+               bitset_t *bs          = bitset_alloca(env->cls->n_regs);
+               const arch_register_t *reg;
+               int col;
+
+               req.limited(irn, -1, bs);
+               col = bitset_next_set(bs, 0);
+               reg = arch_register_for_index(env->cls, col);
+
+               pset_insert_ptr(pre_colored, irn);
+               arch_set_irn_register(env->main_env->arch_env, irn, reg);
+               bitset_set(colors_used, col);
+
+               DBG((env->dbg, LEVEL_2, "pre coloring %+F with %s\n", irn, reg->name));
+
+               return 1;
+       }
+
+       return 0;
+}
+
+/**
+ * Handle register targeting constraints signaled by a Perm.
+ * @param alloc_env    Private data for the allocation phase.
+ * @param perm         The Perm node guarding the constrained node.
+ * @return             The constrained node.
+
+               Pro-coloring works as follows:
+
+         +-----------------------------------+
+         |            Perm                   |
+         +---.-------.--------.---------.----+
+             |       |        |         |
+         +---+--+    |        |         |
+         | Proj |    |        |         |
+         +------+    |        |         |
+                     |        |         |
+                  +--+---+    |         |
+                  | Proj |    |         |
+                  +--.---+    |         |
+                     |        |         |
+                     |     +--+---+     |
+                     |     | Proj |     |
+                     |     +------+     |
+                      |                 |
+                      |             +---+--+
+                       `-.          | Proj | Result:
+                          `._       +---.--+ R1
+                             `.         |
+                               `-.      |
+                                  `._   |
+                                    +`.-+--+
+                                    |Constr| Result:
+                                    +------+ R2
+
+               1) Look at all Projs of the Perm if they have output constraints.
+                  If one has an output constraint, pre-color it, else record it
+                  in the set leftover. Its color has to be chosen after all
+                  constrained nodes are colored. Furthermore record all colors
+                  used in the pre-coloring in the set colors_used.
+
+               2) Look whether the first node not a Proj (this is the constrained
+                  node due to which the Perm has been inserted) has an output
+                  constraint. If yes, pre-color the node accordingly else do nothing
+                  since the node's input constraints are modelled by the Proj's
+                  output constraint.
+
+                  There's one subtle point here: If thenode has an output constraint
+                  and the live range of some Proj ends at that node, we must give
+                  that Proj the color of the constrained node. Otherwise the
+                  available colors may not suffice for the rest of the projs.
+
+               3) At last, color the Projs which have not been colored yet with the
+                  left over colors.
+
+                  So afterwards, everything including the constrained node will
+                  be colored and the assign() phase can complete this coloring.
+                  Note that therefore, we put the pre-colored nodes in a set
+                  called pre_colored().
+
+ */
+static ir_node *handle_constraints_at_perm(be_chordal_alloc_env_t *alloc_env, ir_node *perm)
+{
+       be_chordal_env_t *env      = alloc_env->chordal_env;
+       firm_dbg_module_t *dbg     = env->dbg;
+       const arch_env_t *arch_env = env->main_env->arch_env;
+
+       pset *leftover        = pset_new_ptr(8);
+       pset *pre_colored     = pset_new_ptr(8);
+       bitset_t *colors_used = bitset_alloca(env->cls->n_regs);
+       ir_node *irn, *cnstr, *last;
+       int has_cnstr = 0;
+
+       assert(be_is_Perm(perm));
+
+       DBG((dbg, LEVEL_2, "Constraints on %+F\n", perm));
+
+       /*
+        * Color constrained Projs first.
+        */
+       for(irn = sched_next(perm); is_Proj(irn); irn = sched_next(irn))
+               if(!try_pre_color(env, irn, pre_colored, colors_used))
+                       pset_insert_ptr(leftover, irn);
+
+       cnstr = irn;
+       last  = irn;
+
+       if(get_irn_mode(cnstr) == mode_T) {
+               for(irn = sched_next(cnstr); is_Proj(irn); irn = sched_next(irn))
+                       if(!try_pre_color(env, irn, pre_colored, colors_used))
+                               pset_insert_ptr(leftover, irn);
+
+               last = sched_prev(irn);
+       }
+
+       else
+               try_pre_color(env, cnstr, pre_colored, colors_used);
+
+       pset_insert_pset_ptr(alloc_env->pre_colored, pre_colored);
+
+       for(irn = pset_first(leftover); irn; irn = pset_next(leftover)) {
+               const arch_register_t *reg;
+               ir_node *precol;
+               int colored = 0;
+
+               for(precol = pset_first(pre_colored); precol; precol = pset_next(pre_colored)) {
+                       const arch_register_t *pre_col_reg = arch_get_irn_register(arch_env, precol);
+
+                       if(!values_interfere(irn, precol)) {
+                               reg = arch_get_irn_register(arch_env, precol);
+                               pset_break(pre_colored);
+                               pset_remove_ptr(pre_colored, precol);
+                               DBG((dbg, LEVEL_2, "non-interfering %+F setting to %s\n", irn, reg->name));
+                               colored = 1;
+                               break;
+                       }
+               }
+
+               if(!colored) {
+                       int col = bitset_next_clear(colors_used, 0);
+
+                       assert(col >= 0 && col < env->cls->n_regs && "There must be a register left");
+                       reg = arch_register_for_index(env->cls, col);
+
+                       DBG((dbg, LEVEL_2, "coloring leftover %+F with %s\n", irn, reg->name));
+               }
+
+               arch_set_irn_register(arch_env, irn, reg);
+               pset_insert_ptr(alloc_env->pre_colored, irn);
+               bitset_set(colors_used, reg->index);
+       }
+
+       del_pset(leftover);
+       del_pset(pre_colored);
+
+       return last;
+}
+
+/**
+ * Handle constraint nodes in each basic block.
+ * be_insert_constr_perms() inserts Perm nodes which perm
+ * over all values live at the constrained node right in front
+ * of the constrained node. These Perms signal a constrained node.
+ * For further comments, refer to handle_constraints_at_perm().
+ */
+static void constraints(ir_node *bl, void *data)
+{
+       be_chordal_alloc_env_t *env = data;
+       arch_env_t *arch_env        = env->chordal_env->main_env->arch_env;
+       ir_node *irn;
+
+       for(irn = sched_first(bl); !sched_is_end(irn); irn = sched_next(irn)) {
+               if(be_is_Perm(irn) && arch_irn_has_reg_class(arch_env, irn, 0, env->chordal_env->cls))
+                       irn = handle_constraints_at_perm(env, irn);
+       }
+}
+
 /**
  * Annotate the register pressure to the nodes and compute
  * the liveness intervals.
@@ -343,37 +364,39 @@ static void pressure(ir_node *block, void *env_ptr)
 #define border_use(irn, step, real) \
        border_add(env, head, irn, step, ++pressure, 0, real)
 
-       be_chordal_env_t *env = env_ptr;
-       bitset_t *live = env->live;
+       be_chordal_alloc_env_t *alloc_env = env_ptr;
+       be_chordal_env_t *env             = alloc_env->chordal_env;
+       bitset_t *live                    = alloc_env->live;
+       firm_dbg_module_t *dbg            = env->dbg;
        ir_node *irn;
 
        int i, n;
        unsigned step = 0;
        unsigned pressure = 0;
        struct list_head *head;
-       pset *live_in = get_live_in(block);
-       pset *live_end = get_live_end(block);
-  const arch_register_class_t *cls = env->cls;
+       pset *live_in = put_live_in(block, pset_new_ptr_default());
+       pset *live_end = put_live_end(block, pset_new_ptr_default());
 
-       DBG((dbg, LEVEL_1, "Computing pressure in block %n\n", block));
+       DBG((dbg, LEVEL_1, "Computing pressure in block %+F\n", block));
        bitset_clear_all(live);
 
        /* Set up the border list in the block info */
-  head = obstack_alloc(&env->obst, sizeof(*head));
+       head = obstack_alloc(&env->obst, sizeof(*head));
        INIT_LIST_HEAD(head);
-  pmap_insert(env->border_heads, block, head);
+       assert(pmap_get(env->border_heads, block) == NULL);
+       pmap_insert(env->border_heads, block, head);
 
        /*
         * Make final uses of all values live out of the block.
-        * They are neccessary to build up real intervals.
+        * They are necessary to build up real intervals.
         */
        for(irn = pset_first(live_end); irn; irn = pset_next(live_end)) {
-               DBG((dbg, LEVEL_3, "\tMaking live: %n/%d\n", irn, get_irn_graph_nr(irn)));
-               bitset_set(live, get_irn_graph_nr(irn));
-    if(arch_irn_has_reg_class(env->arch_env, irn, 0, cls))
-      border_use(irn, step, 0);
+               if(has_reg_class(env, irn)) {
+                       DBG((dbg, LEVEL_3, "\tMaking live: %+F/%d\n", irn, get_irn_graph_nr(irn)));
+                       bitset_set(live, get_irn_graph_nr(irn));
+                       border_use(irn, step, 0);
+               }
        }
-
        ++step;
 
        /*
@@ -381,24 +404,18 @@ static void pressure(ir_node *block, void *env_ptr)
         * relevant for the interval borders.
         */
        sched_foreach_reverse(block, irn) {
-               DBG((dbg, LEVEL_1, "\tinsn: %n, pressure: %d\n", irn, pressure));
+               DBG((dbg, LEVEL_1, "\tinsn: %+F, pressure: %d\n", irn, pressure));
                DBG((dbg, LEVEL_2, "\tlive: %b\n", live));
 
-    /*
-     * If the node defines some value, which can put into a
-     * register of the current class, make a border for it.
-     */
-               if(arch_irn_has_reg_class(env->arch_env, irn, 0, cls)) {
-      bitset_pos_t elm;
+               /*
+                * If the node defines some value, which can put into a
+                * register of the current class, make a border for it.
+                */
+               if(has_reg_class(env, irn)) {
                        int nr = get_irn_graph_nr(irn);
 
                        bitset_clear(live, nr);
                        border_def(irn, step, 1);
-
-#ifdef BUILD_GRAPH
-      bitset_foreach(live, elm)
-        add_if(env, nr, (int) elm);
-#endif
                }
 
                /*
@@ -408,10 +425,10 @@ static void pressure(ir_node *block, void *env_ptr)
                        for(i = 0, n = get_irn_arity(irn); i < n; ++i) {
                                ir_node *op = get_irn_n(irn, i);
 
-                               if(arch_irn_has_reg_class(env->arch_env, op, 0, cls)) {
+                               if(has_reg_class(env, op)) {
                                        int nr = get_irn_graph_nr(op);
 
-                                       DBG((dbg, LEVEL_4, "\t\tpos: %d, use: %n\n", i, op));
+                                       DBG((dbg, LEVEL_4, "\t\tpos: %d, use: %+F\n", i, op));
 
                                        if(!bitset_is_set(live, nr)) {
                                                border_use(op, step, 1);
@@ -420,7 +437,6 @@ static void pressure(ir_node *block, void *env_ptr)
                                }
                        }
                }
-
                ++step;
        }
 
@@ -428,7 +444,7 @@ static void pressure(ir_node *block, void *env_ptr)
         * Add initial defs for all values live in.
         */
        for(irn = pset_first(live_in); irn; irn = pset_next(live_in)) {
-               if(arch_irn_has_reg_class(env->arch_env, irn, 0, cls)) {
+               if(has_reg_class(env, irn)) {
 
                        /* Mark the value live in. */
                        bitset_set(live, get_irn_graph_nr(irn));
@@ -437,34 +453,35 @@ static void pressure(ir_node *block, void *env_ptr)
                        border_def(irn, step, 0);
                }
        }
+
+
+  del_pset(live_in);
+  del_pset(live_end);
 }
 
 static void assign(ir_node *block, void *env_ptr)
 {
-       be_chordal_env_t *env = env_ptr;
-       struct obstack *obst = &env->obst;
-       bitset_t *live = env->live;
-       bitset_t *colors = env->colors;
-       bitset_t *in_colors = env->in_colors;
-  const arch_register_class_t *cls = env->cls;
-
-       /* Mark the obstack level and allocate the temporary tmp_colors */
-       void *obstack_level = obstack_base(obst);
-       /*bitset_t *tmp_colors = bitset_obstack_alloc(obst, env->colors_n);*/
+       be_chordal_alloc_env_t *alloc_env = env_ptr;
+       be_chordal_env_t *env       = alloc_env->chordal_env;
+       firm_dbg_module_t *dbg      = env->dbg;
+       bitset_t *live              = alloc_env->live;
+       bitset_t *colors            = alloc_env->colors;
+       bitset_t *in_colors         = alloc_env->in_colors;
+       const arch_env_t *arch_env  = env->main_env->arch_env;
 
        const ir_node *irn;
        border_t *b;
        struct list_head *head = get_block_border_head(env, block);
-       pset *live_in = get_live_in(block);
+       pset *live_in = put_live_in(block, pset_new_ptr_default());
 
        bitset_clear_all(live);
        bitset_clear_all(colors);
        bitset_clear_all(in_colors);
 
-       DBG((dbg, LEVEL_4, "Assigning colors for block %n\n", block));
+       DBG((dbg, LEVEL_4, "Assigning colors for block %+F\n", block));
        DBG((dbg, LEVEL_4, "\tusedef chain for block\n"));
        list_for_each_entry(border_t, b, head, list) {
-               DBG((dbg, LEVEL_4, "\t%s %n/%d\n", b->is_def ? "def" : "use",
+               DBG((dbg, LEVEL_4, "\t%s %+F/%d\n", b->is_def ? "def" : "use",
                                        b->irn, get_irn_graph_nr(b->irn)));
        }
 
@@ -474,11 +491,11 @@ static void assign(ir_node *block, void *env_ptr)
         * allocated before), we have to mark their colors as used also.
         */
        for(irn = pset_first(live_in); irn; irn = pset_next(live_in)) {
-               if(arch_irn_has_reg_class(env->arch_env, irn, 0, cls)) {
-      const arch_register_t *reg = arch_get_irn_register(env->arch_env, irn, 0);
-      int col;
+               if(has_reg_class(env, irn)) {
+                       const arch_register_t *reg = arch_get_irn_register(arch_env, irn);
+                       int col;
 
-      assert(reg && "Nodfe must have been assigned a register");
+                       assert(reg && "Node must have been assigned a register");
                        col = arch_register_get_index(reg);
 
                        /* Mark the color of the live in value as used. */
@@ -504,34 +521,39 @@ static void assign(ir_node *block, void *env_ptr)
                 * color.
                 */
                if(b->is_def && !is_live_in(block, irn)) {
-      const arch_register_t *reg;
+                       const arch_register_t *reg;
                        int col = NO_COLOR;
 
-                       DBG((dbg, LEVEL_4, "\tcolors in use: %b\n", colors));
-
-      col = bitset_next_clear(colors, 0);
-      reg = arch_register_for_index(env->cls, col);
+                       if(pset_find_ptr(alloc_env->pre_colored, irn)) {
+                               reg = arch_get_irn_register(arch_env, irn);
+                               col = reg->index;
+                               assert(!bitset_is_set(colors, col) && "pre-colored register must be free");
+                       }
 
-      assert(arch_get_irn_register(env->arch_env, irn, 0) == NULL
-          && "This node must not have been assigned a register yet");
-                       assert(!bitset_is_set(live, nr) && "Value's definition must not have been encountered");
+                       else {
+                               col = bitset_next_clear(colors, 0);
+                               reg = arch_register_for_index(env->cls, col);
+                               assert(arch_get_irn_register(arch_env, irn) == NULL && "This node must not have been assigned a register yet");
+                       }
 
                        bitset_set(colors, col);
-                       bitset_set(live, nr);
+                       arch_set_irn_register(arch_env, irn, reg);
 
-                       arch_set_irn_register(env->arch_env, irn, 0, reg);
-                       DBG((dbg, LEVEL_1, "\tassigning register %s(%d) to %n\n",
+                       DBG((dbg, LEVEL_1, "\tassigning register %s(%d) to %+F\n",
             arch_register_get_name(reg), col, irn));
+
+                       assert(!bitset_is_set(live, nr) && "Value's definition must not have been encountered");
+                       bitset_set(live, nr);
                }
 
                /* Clear the color upon a use. */
                else if(!b->is_def) {
-      const arch_register_t *reg = arch_get_irn_register(env->arch_env, irn, 0);
+                       const arch_register_t *reg = arch_get_irn_register(arch_env, irn);
                        int col;
 
-      assert(reg && "Register must have been assigned");
+                       assert(reg && "Register must have been assigned");
 
-      col = arch_register_get_index(reg);
+                       col = arch_register_get_index(reg);
                        assert(bitset_is_set(live, nr) && "Cannot have a non live use");
 
                        bitset_clear(colors, col);
@@ -539,106 +561,52 @@ static void assign(ir_node *block, void *env_ptr)
                }
        }
 
-       /* Free the auxillary data on the obstack. */
-       obstack_free(obst, obstack_level);
+       del_pset(live_in);
 }
 
-void be_ra_chordal_init(void)
+void be_ra_chordal_color(be_chordal_env_t *chordal_env)
 {
-       dbg = firm_dbg_register(DBG_CHORDAL);
-       firm_dbg_set_mask(dbg, 0);
-}
+       int node_count        = get_graph_node_count(chordal_env->irg);
+       int colors_n          = arch_register_class_n_regs(chordal_env->cls);
+       ir_graph *irg         = chordal_env->irg;
 
-be_chordal_env_t *be_ra_chordal(ir_graph *irg,
-    const arch_env_t *arch_env,
-    const arch_register_class_t *cls)
-{
-       int node_count = get_graph_node_count(irg);
-  int colors_n = arch_register_class_n_regs(cls);
-       be_chordal_env_t *env = malloc(sizeof(*env));
+       be_chordal_alloc_env_t env;
 
        if(get_irg_dom_state(irg) != dom_consistent)
                compute_doms(irg);
 
-       obstack_init(&env->obst);
-
-#ifdef BUILD_GRAPH
-       env->edges = new_set(if_edge_cmp, node_count);
-       env->nodes = new_set(if_node_cmp, node_count);
-#endif
+       env.chordal_env  = chordal_env;
+       env.live         = bitset_malloc(node_count);
+       env.colors       = bitset_malloc(colors_n);
+       env.in_colors    = bitset_malloc(colors_n);
+       env.colors_n     = colors_n;
+       env.pre_colored  = pset_new_ptr_default();
 
-       env->live = bitset_obstack_alloc(&env->obst, node_count);
-       env->colors = bitset_obstack_alloc(&env->obst, colors_n);
-       env->in_colors = bitset_obstack_alloc(&env->obst, colors_n);
-       env->colors_n = colors_n;
-  env->cls = cls;
-  env->arch_env = arch_env;
-  env->irg = irg;
-  env->border_heads = pmap_create();
+       /* Handle register targeting constraints */
+       dom_tree_walk_irg(irg, constraints, NULL, &env);
 
        /* First, determine the pressure */
-       dom_tree_walk_irg(irg, pressure, NULL, env);
-
-       /* Insert probable spills */
-       be_ra_chordal_spill(env);
+       dom_tree_walk_irg(irg, pressure, NULL, &env);
 
        /* Assign the colors */
-       dom_tree_walk_irg(irg, assign, NULL, env);
-
-#ifdef DUMP_IFG
-  dump_ifg(env);
-#endif
+       dom_tree_walk_irg(irg, assign, NULL, &env);
 
 #ifdef DUMP_INTERVALS
        {
                char buf[128];
-    plotter_t *plotter;
-
-               ir_snprintf(buf, sizeof(buf), "ifg_%s_%F.eps", cls->name, irg);
-    plotter = new_plotter_ps(buf);
+       plotter_t *plotter;
 
-    draw_interval_tree(&draw_chordal_def_opts, env, plotter, arch_env, cls);
-    plotter_free(plotter);
-       }
-#endif
+               ir_snprintf(buf, sizeof(buf), "ifg_%s_%F.eps", chordal_env->cls->name, irg);
+       plotter = new_plotter_ps(buf);
 
-  return env;
-}
-
-void be_ra_chordal_done(be_chordal_env_t *env)
-{
-#ifdef BUILD_GRAPH
-       {
-               if_node_t *ifn;
-               for(ifn = set_first(env->nodes); ifn; ifn = set_next(env->nodes))
-                       free(ifn->neighb);
-               free(env->nodes);
-               free(env->edges);
+       draw_interval_tree(&draw_chordal_def_opts, chordal_env, plotter);
+       plotter_free(plotter);
        }
 #endif
 
-  pmap_destroy(env->border_heads);
-       obstack_free(&env->obst, NULL);
-       free(env);
-}
-
-int nodes_interfere(const be_chordal_env_t *env, const ir_node *a, const ir_node *b)
-{
-#ifdef BUILD_GRAPH
-       return are_connected(env, get_irn_graph_nr(a), get_irn_graph_nr(b));
-#else
-       return values_interfere(a, b);
-#endif /* BUILD_GRAPH */
-}
-
-#ifdef BUILD_GRAPH
+       free(env.live);
+       free(env.colors);
+       free(env.in_colors);
 
-set *be_ra_get_ifg_edges(const be_chordal_env_t *env) {
-       return env->edges;
+       del_pset(env.pre_colored);
 }
-
-set *be_ra_get_ifg_nodes(const be_chordal_env_t *env) {
-       return env->nodes;
-}
-
-#endif