Re-implemented constraint coloring
[libfirm] / ir / be / bechordal.c
index e84baa1..a98e8a4 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"
@@ -18,6 +26,7 @@
 #include "list.h"
 #include "bitset.h"
 #include "iterator.h"
+#include "bipartite.h"
 
 #include "irmode_t.h"
 #include "irgraph_t.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 *ignore_colors;        /**< A mask of colors which shall be not used in allocation (ignored). */
+       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)
-{
-       const if_edge_t *e1 = p1;
-       const if_edge_t *e2 = p2;
-
-       return !(e1->src == e2->src && e1->tgt == e2->tgt);
-}
-
-static int if_node_cmp(const void *p1, const void *p2, size_t size)
-{
-       const if_node_t *n1 = p1;
-       const if_node_t *n2 = p2;
-
-       return n1->nnr != n2->nnr;
-}
-
-static INLINE if_edge_t *edge_init(if_edge_t *edge, int src, int tgt)
+static void check_border_list(struct list_head *head)
 {
-       /* 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);
+  border_t *x;
+  list_for_each_entry(border_t, x, head, list) {
+    assert(x->magic == BORDER_FOURCC);
+  }
 }
 
-static INLINE int are_connected(const be_chordal_env_t *env, int src, int tgt)
+static void check_heads(be_chordal_env_t *env)
 {
-       if_edge_t edge;
-       edge_init(&edge, src, tgt);
-       return set_find(env->edges, &edge, sizeof(edge), IF_EDGE_HASH(&edge)) != NULL;
+  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);
+  }
 }
 
-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)
-{
-       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);
-
-                       ir_fprintf(f, "\tn%d [label=\"%+F\"]\n", nr, irn);
-               }
-
-               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
@@ -203,6 +115,7 @@ 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;
 
@@ -213,10 +126,8 @@ 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
        }
 
        /*
@@ -227,9 +138,7 @@ 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;
@@ -238,12 +147,303 @@ 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 %+F, 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)
+
+typedef struct _operand_t operand_t;
+
+struct _operand_t {
+       ir_node *irn;
+       ir_node *carrier;
+       operand_t *partner;
+       int pos;
+       arch_register_req_t req;
+};
+
+typedef struct {
+       operand_t *ops;
+       int n_ops;
+       int use_start;
+       ir_node *next_insn;
+       unsigned has_constraints : 1;
+} insn_t;
+
+static insn_t *scan_insn(be_chordal_env_t *env, ir_node *irn, struct obstack *obst)
+{
+       const arch_env_t *arch_env = env->main_env->arch_env;
+       operand_t o;
+       insn_t *insn;
+       int i, n;
+
+       insn = obstack_alloc(obst, sizeof(insn[0]));
+       memset(insn, 0, sizeof(insn[0]));
+
+       insn->next_insn = sched_next(irn);
+       if(get_irn_mode(irn) == mode_T) {
+               ir_node *p;
+
+               for(p = sched_next(irn); is_Proj(p); p = sched_next(p)) {
+                       if(arch_irn_consider_in_reg_alloc(arch_env, env->cls, p)) {
+                               o.carrier = p;
+                               o.irn     = irn;
+                               o.pos     = -(get_Proj_proj(p) + 1);
+                               o.partner = NULL;
+                               arch_get_register_req(arch_env, &o.req, p, -1);
+                               obstack_grow(obst, &o, sizeof(o));
+                               insn->n_ops++;
+                               insn->has_constraints |= arch_register_req_is(&o.req, limited);
+                       }
+               }
+
+               insn->next_insn = p;
+       }
+
+       else if(arch_irn_consider_in_reg_alloc(arch_env, env->cls, irn)) {
+               o.carrier = irn;
+               o.irn     = irn;
+               o.pos     = -1;
+               o.partner = NULL;
+               arch_get_register_req(arch_env, &o.req, irn, -1);
+               obstack_grow(obst, &o, sizeof(o));
+               insn->n_ops++;
+               insn->has_constraints |= arch_register_req_is(&o.req, limited);
+       }
+
+       insn->use_start = insn->n_ops;
+
+       for(i = 0, n = get_irn_arity(irn); i < n; ++i) {
+               ir_node *op = get_irn_n(irn, i);
+
+               if(arch_irn_consider_in_reg_alloc(arch_env, env->cls, op)) {
+                       o.carrier = op;
+                       o.irn     = irn;
+                       o.pos     = i;
+                       o.partner = NULL;
+                       arch_get_register_req(arch_env, &o.req, irn, i);
+                       obstack_grow(obst, &o, sizeof(o));
+                       insn->n_ops++;
+                       insn->has_constraints |= arch_register_req_is(&o.req, limited);
+               }
+       }
+
+       insn->ops = obstack_finish(obst);
+       return insn;
+}
+
+static operand_t *find_unpaired_use(insn_t *insn, const operand_t *op, int can_be_constrained)
+{
+       int i;
+       operand_t *res = NULL;
+
+       for(i = insn->use_start; i < insn->n_ops; ++i) {
+               operand_t *op = &insn->ops[i];
+               int has_constraint = arch_register_req_is(&op->req, limited);
+
+               if(!values_interfere(op->carrier, op->irn) && !op->partner && (!has_constraint || can_be_constrained)) {
+                       if(arch_register_req_is(&op->req, should_be_same) && op->req.other == op->carrier)
+                               return op;
+                       else
+                               res = op;
+               }
+       }
+
+       return res;
+}
+
+static void pair_up_operands(insn_t *insn)
+{
+       firm_dbg_module_t *dbg = firm_dbg_register("firm.be.chordal.constr");
+       int i;
+
+       for(i = 0; i < insn->use_start; ++i) {
+               operand_t *op      = &insn->ops[i];
+               int has_constraint = arch_register_req_is(&op->req, limited);
+               operand_t *partner = find_unpaired_use(insn, op, !has_constraint);
+
+               if(partner) {
+                       op->partner = partner;
+                       partner->partner = op;
+               }
+       }
+}
+
+static ir_node *handle_constraints(be_chordal_alloc_env_t *alloc_env, ir_node *irn)
+{
+       be_chordal_env_t *env  = alloc_env->chordal_env;
+       void *base             = obstack_base(&env->obst);
+       insn_t *insn           = scan_insn(env, irn, &env->obst);
+       ir_node *res           = insn->next_insn;
+
+       if(insn->has_constraints) {
+               firm_dbg_module_t *dbg = firm_dbg_register("firm.be.chordal.constr");
+               const arch_env_t *aenv = env->main_env->arch_env;
+               int n_regs             = env->cls->n_regs;
+               bitset_t *bs           = bitset_alloca(n_regs);
+               ir_node **alloc_nodes  = alloca(n_regs * sizeof(alloc_nodes[0]));
+               bipartite_t *bp        = bipartite_new(n_regs, n_regs);
+               int *assignment        = alloca(n_regs * sizeof(assignment[0]));
+               pmap *partners         = pmap_create();
+
+               int i, n_alloc;
+               long col;
+               const ir_edge_t *edge;
+               ir_node *perm = insert_Perm_after(aenv, env->cls, env->dom_front, sched_prev(irn));
+
+               /* Registers are propagated by insert_Perm_after(). Clean them here! */
+               if(perm) {
+                       foreach_out_edge(perm, edge) {
+                               ir_node *proj = get_edge_src_irn(edge);
+                               arch_set_irn_register(aenv, proj, NULL);
+                       }
+               }
+
+
+               be_liveness(env->irg);
+               insn = scan_insn(env, irn, &env->obst);
+
+               DBG((dbg, LEVEL_1, "handling constraints for %+F\n", irn));
+
+               /*
+                * If there was no Perm made, nothing was alive in this register class.
+                * This means, that the node has no operands, thus no input constraints.
+                * so it had output constraints. The other results then can be assigned freeliy.
+                */
+
+               pair_up_operands(insn);
+
+               for(i = 0, n_alloc = 0; i < insn->n_ops; ++i) {
+                       operand_t *op = &insn->ops[i];
+                       if(arch_register_req_is(&op->req, limited)) {
+                               pmap_insert(partners, op->carrier, op->partner ? op->partner->carrier : NULL);
+                               alloc_nodes[n_alloc] = op->carrier;
+
+                               DBG((dbg, LEVEL_2, "\tassociating %+F and %+F\n", op->carrier, pmap_get(partners, op->carrier)));
+
+                               bitset_clear_all(bs);
+                               op->req.limited(op->req.limited_env, bs);
+                               bitset_andnot(bs, alloc_env->ignore_colors);
+
+                               bitset_foreach(bs, col)
+                                       bipartite_add(bp, n_alloc, col);
+
+                               n_alloc++;
+                       }
+               }
+
+               if(perm) {
+                       foreach_out_edge(perm, edge) {
+                               ir_node *proj = get_edge_src_irn(edge);
+
+                               assert(is_Proj(proj));
+
+                               if(values_interfere(proj, irn)) {
+                                       assert(n_alloc < n_regs);
+                                       alloc_nodes[n_alloc] = proj;
+                                       pmap_insert(partners, proj, NULL);
+
+                                       bitset_clear_all(bs);
+                                       arch_get_allocatable_regs(aenv, proj, -1, bs);
+                                       bitset_andnot(bs, alloc_env->ignore_colors);
+                                       bitset_foreach(bs, col)
+                                               bipartite_add(bp, n_alloc, col);
+
+                                       n_alloc++;
+                               }
+                       }
+               }
+
+               bipartite_matching(bp, assignment);
+
+               for(i = 0; i < n_alloc; ++i) {
+                       int j;
+                       ir_node *nodes[2];
+                       const arch_register_t *reg = arch_register_for_index(env->cls, assignment[i]);
+
+                       nodes[0] = alloc_nodes[i];
+                       nodes[1] = pmap_get(partners, alloc_nodes[i]);
+
+                       for(j = 0; j < 2; ++j) {
+                               if(!nodes[j])
+                                       continue;
+
+                               arch_set_irn_register(aenv, nodes[j], reg);
+                               pset_hinsert_ptr(alloc_env->pre_colored, nodes[j]);
+                               DBG((dbg, LEVEL_2, "\tsetting %+F to register %s\n", nodes[j], reg->name));
+                       }
+               }
+
+
+               if(perm) {
+                       bitset_clear_all(bs);
+                       foreach_out_edge(perm, edge) {
+                               ir_node *proj              = get_edge_src_irn(edge);
+                               const arch_register_t *reg = arch_get_irn_register(aenv, proj);
+
+                               if(reg != NULL)
+                                       bitset_set(bs, reg->index);
+                       }
+
+                       // bitset_or(bs, alloc_env->ignore_colors);
+                       foreach_out_edge(perm, edge) {
+                               ir_node *proj              = get_edge_src_irn(edge);
+                               const arch_register_t *reg = arch_get_irn_register(aenv, proj);
+
+                               DBG((dbg, LEVEL_2, "\tchecking reg of %+F: %s\n", proj, reg ? reg->name : "<none>"));
+
+                               if(reg == NULL) {
+                                       col = bitset_next_clear(bs, 0);
+                                       reg = arch_register_for_index(env->cls, col);
+                                       bitset_set(bs, reg->index);
+                                       arch_set_irn_register(aenv, proj, reg);
+                                       pset_insert_ptr(alloc_env->pre_colored, proj);
+                                       DBG((dbg, LEVEL_2, "\tsetting %+F to register %s\n", proj, reg->name));
+                               }
+                       }
+               }
+
+               pmap_destroy(partners);
+       }
+
+       obstack_free(&env->obst, base);
+       return res;
+}
+
+/**
+ * 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)
+{
+       firm_dbg_module_t *dbg      = firm_dbg_register("firm.be.chordal.constr");
+       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 = handle_constraints(env, irn);
+       }
+}
+
 /**
  * Annotate the register pressure to the nodes and compute
  * the liveness intervals.
@@ -260,8 +460,10 @@ 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;
@@ -270,7 +472,6 @@ static void pressure(ir_node *block, void *env_ptr)
        struct list_head *head;
        pset *live_in = put_live_in(block, pset_new_ptr_default());
        pset *live_end = put_live_end(block, pset_new_ptr_default());
-       const arch_register_class_t *cls = env->cls;
 
        DBG((dbg, LEVEL_1, "Computing pressure in block %+F\n", block));
        bitset_clear_all(live);
@@ -278,6 +479,7 @@ static void pressure(ir_node *block, void *env_ptr)
        /* Set up the border list in the block info */
        head = obstack_alloc(&env->obst, sizeof(*head));
        INIT_LIST_HEAD(head);
+       assert(pmap_get(env->border_heads, block) == NULL);
        pmap_insert(env->border_heads, block, head);
 
        /*
@@ -285,10 +487,11 @@ static void pressure(ir_node *block, void *env_ptr)
         * 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: %+F/%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))
+               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;
 
@@ -300,21 +503,15 @@ static void pressure(ir_node *block, void *env_ptr)
                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
                }
 
                /*
@@ -324,7 +521,7 @@ 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: %+F\n", i, op));
@@ -343,7 +540,7 @@ 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));
@@ -353,22 +550,20 @@ static void pressure(ir_node *block, void *env_ptr)
                }
        }
 
-    del_pset(live_in);
-    del_pset(live_end);
+
+  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;
@@ -392,11 +587,11 @@ 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 && "Node 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. */
@@ -422,34 +617,39 @@ 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 %+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);
@@ -457,107 +657,75 @@ 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);
+       del_pset(live_in);
 }
 
-void be_ra_chordal_init(void)
-{
-       dbg = firm_dbg_register(DBG_CHORDAL);
-       firm_dbg_set_mask(dbg, 0);
-}
 
-be_chordal_env_t *be_ra_chordal(ir_graph *irg,
-    const arch_env_t *arch_env,
-    const arch_register_class_t *cls)
+
+void be_ra_chordal_color(be_chordal_env_t *chordal_env)
 {
-       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));
+       int i;
+       int colors_n          = arch_register_class_n_regs(chordal_env->cls);
+       ir_graph *irg         = chordal_env->irg;
+
+       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);
+       env.chordal_env   = chordal_env;
+       env.colors_n      = colors_n;
+       env.colors        = bitset_malloc(colors_n);
+       env.ignore_colors = bitset_malloc(colors_n);
+       env.in_colors     = bitset_malloc(colors_n);
+       env.pre_colored   = pset_new_ptr_default();
+
+       bitset_clear_all(env.ignore_colors);
+#if 0
+       for(i = 0; i < chordal_env->cls->n_regs; ++i) {
+               const arch_register_t *reg = &chordal_env->cls->regs[i];
+               if(arch_register_type_is(reg, ignore))
+                       bitset_set(env.ignore_colors, reg->index);
+       }
 #endif
 
-       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);
+       {
+               char buf[128];
+               snprintf(buf, sizeof(buf), "-%s-constr", chordal_env->cls->name);
+               dump_ir_block_graph_sched(chordal_env->irg, buf);
+       }
+
+       be_numbering(irg);
+       env.live = bitset_malloc(get_graph_node_count(chordal_env->irg));
 
-       /* Insert probable spills */
-       be_ra_chordal_spill(env);
+       /* First, determine the pressure */
+       dom_tree_walk_irg(irg, pressure, NULL, &env);
 
        /* Assign the colors */
-       dom_tree_walk_irg(irg, assign, NULL, env);
+       dom_tree_walk_irg(irg, assign, NULL, &env);
 
-#ifdef DUMP_IFG
-       dump_ifg(env);
-#endif
+       be_numbering_done(irg);
 
 #ifdef DUMP_INTERVALS
        {
                char buf[128];
        plotter_t *plotter;
 
-               ir_snprintf(buf, sizeof(buf), "ifg_%s_%F.eps", cls->name, irg);
+               ir_snprintf(buf, sizeof(buf), "ifg_%s_%F.eps", chordal_env->cls->name, irg);
        plotter = new_plotter_ps(buf);
 
-       draw_interval_tree(&draw_chordal_def_opts, env, plotter, arch_env, cls);
+       draw_interval_tree(&draw_chordal_def_opts, chordal_env, plotter);
        plotter_free(plotter);
        }
 #endif
-       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);
-       }
-#endif
-
-  pmap_destroy(env->border_heads);
-       obstack_free(&env->obst, NULL);
-       free(env);
-}
+       free(env.live);
+       free(env.colors);
+       free(env.in_colors);
+       free(env.ignore_colors);
 
-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 */
+       del_pset(env.pre_colored);
 }
-
-#ifdef BUILD_GRAPH
-
-set *be_ra_get_ifg_edges(const be_chordal_env_t *env) {
-       return env->edges;
-}
-
-set *be_ra_get_ifg_nodes(const be_chordal_env_t *env) {
-       return env->nodes;
-}
-
-#endif