X-Git-Url: http://nsz.repo.hu/git/?a=blobdiff_plain;f=ir%2Fbe%2Fbechordal.c;h=a98e8a477e1220d8a633f97372c998fd9a2812a1;hb=cf5a8a237e8ec6c54251fa29701488dcf47f94d4;hp=65e54fe0b01ac0ad143fb0d0b9c64c5739558204;hpb=9d439a4d682b1c9a697b2fabfffe62d43998da3f;p=libfirm

diff --git a/ir/be/bechordal.c b/ir/be/bechordal.c
index 65e54fe0b..a98e8a477 100644
--- a/ir/be/bechordal.c
+++ b/ir/be/bechordal.c
@@ -11,6 +11,14 @@
 #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"
@@ -33,147 +42,36 @@
 #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;
 
 #include "fourcc.h"
 
 /* Make a fourcc for border checking. */
 #define BORDER_FOURCC				FOURCC('B', 'O', 'R', 'D')
 
-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)
-{
-	/* 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)
-{
-	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 */
-
 static void check_border_list(struct list_head *head)
 {
   border_t *x;
@@ -217,7 +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));
+		memset(def, 0, sizeof(*def));
 		b->other_end = def;
 		def->other_end = b;
 
@@ -248,19 +146,302 @@ static INLINE border_t *border_add(be_chordal_env_t *env, struct list_head *head
 	b->is_real = is_real;
 	b->irn = irn;
 	b->step = step;
-  check_heads(env);
 	list_add_tail(&b->list, head);
-  check_heads(env);
-	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->arch_env, irn, arch_pos_make_out(0), env->cls);
+  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);
+	}
 }
 
 /**
@@ -279,8 +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;
@@ -289,7 +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);
@@ -297,7 +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);
+	assert(pmap_get(env->border_heads, block) == NULL);
 	pmap_insert(env->border_heads, block, head);
 
 	/*
@@ -305,10 +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(has_reg_class(env, irn))
+		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;
 
@@ -320,21 +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 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)) {
-			bitset_pos_t elm;
 			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
 		}
 
 		/*
@@ -373,7 +550,6 @@ static void pressure(ir_node *block, void *env_ptr)
 		}
 	}
 
-  check_heads(env);
 
   del_pset(live_in);
   del_pset(live_end);
@@ -381,25 +557,19 @@ static void pressure(ir_node *block, void *env_ptr)
 
 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 = put_live_in(block, pset_new_ptr_default());
 
-  check_heads(env);
-
-
 	bitset_clear_all(live);
 	bitset_clear_all(colors);
 	bitset_clear_all(in_colors);
@@ -418,10 +588,10 @@ static void assign(ir_node *block, void *env_ptr)
 	 */
 	for(irn = pset_first(live_in); irn; irn = pset_next(live_in)) {
 		if(has_reg_class(env, irn)) {
-      const arch_register_t *reg = arch_get_irn_register(env->arch_env, irn, 0);
-      int col;
+			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. */
@@ -447,34 +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);
@@ -482,146 +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, -1);
-}
 
-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);
+	}
 
-	/* Insert probable spills */
-	be_ra_chordal_spill(env);
+	be_numbering(irg);
+	env.live = bitset_malloc(get_graph_node_count(chordal_env->irg));
+
+	/* 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_check(be_chordal_env_t *chordal_env) {
-	const arch_env_t *arch_env;
-	struct obstack ob;
-	pmap_entry *pme;
-	ir_node **nodes, *n1, *n2;
-	int i, o;
-
-	arch_env = chordal_env->arch_env;
-
-	/* Collect all irns */
-	obstack_init(&ob);
-	pmap_foreach(chordal_env->border_heads, pme) {
-		border_t *curr;
-		struct list_head *head = pme->value;
-		list_for_each_entry(border_t, curr, head, list)
-			if (curr->is_def && curr->is_real)
-				if (arch_get_irn_reg_class(arch_env, curr->irn, arch_pos_make_out(0)) == chordal_env->cls)
-					obstack_ptr_grow(&ob, curr->irn);
-	}
-	obstack_ptr_grow(&ob, NULL);
-	nodes = (ir_node **) obstack_finish(&ob);
-
-	/* Check them */
-	for (i = 0, n1 = nodes[i]; n1; n1 = nodes[++i]) {
-		const arch_register_t *n1_reg, *n2_reg;
-
-		n1_reg = arch_get_irn_register(arch_env, n1, 0);
-		assert(arch_reg_is_allocatable(arch_env, n1, arch_pos_make_out(0), n1_reg) && "Register constraint does not hold");
-
-		for (o = i+1, n2 = nodes[o]; n2; n2 = nodes[++o]) {
-			n2_reg = arch_get_irn_register(arch_env, n2, 0);
-			assert(!(nodes_interfere(chordal_env, n1, n2) && n1_reg == n2_reg) && "Interfering values have the same color!");
-		}
-	}
-	obstack_free(&ob, NULL);
-}
-
-/* BETTER #ifdef BUILD_GRAPH --> faster version of checker with edges */
-
-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);
-}
-
-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
 
-set *be_ra_get_ifg_edges(const be_chordal_env_t *env) {
-	return env->edges;
-}
+	free(env.live);
+	free(env.colors);
+	free(env.in_colors);
+	free(env.ignore_colors);
 
-set *be_ra_get_ifg_nodes(const be_chordal_env_t *env) {
-	return env->nodes;
+	del_pset(env.pre_colored);
 }
-
-#endif