no strange stuff for including alloca anymore, use xmalloc.h
[libfirm] / ir / be / bechordal.c
index 9af2022..ad144c4 100644 (file)
@@ -1,12 +1,12 @@
 /**
  * Chordal register allocation.
  * @author Sebastian Hack
- * @date 8.12.2004
+ * @date   8.12.2004
+ * @cvs-id $Id$
  *
  * Copyright (C) Universitaet Karlsruhe
  * Released under the GPL
  */
-
 #ifdef HAVE_CONFIG_H
 #include "config.h"
 #endif
 #include "pset.h"
 #include "list.h"
 #include "bitset.h"
+#include "raw_bitset.h"
 #include "iterator.h"
+#include "bipartite.h"
+#include "hungarian.h"
 
 #include "irmode_t.h"
 #include "irgraph_t.h"
 #include "irgwalk.h"
 #include "irdump.h"
 #include "irdom.h"
+#include "irtools.h"
 #include "debug.h"
 #include "xmalloc.h"
 
 #include "beutil.h"
 #include "besched.h"
-#include "benumb_t.h"
 #include "besched_t.h"
 #include "belive_t.h"
+#include "benode_t.h"
 #include "bearch.h"
+#include "beirgmod.h"
+#include "beifg.h"
+#include "beinsn_t.h"
+#include "bestatevent.h"
+#include "beirg_t.h"
 
 #include "bechordal_t.h"
 #include "bechordal_draw.h"
 
-#define DBG_LEVEL 0 //SET_LEVEL_4
+DEBUG_ONLY(static firm_dbg_module_t *dbg = NULL;)
+
 #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 *tmp_colors;           /**< An auxiliary bitset which is as long as the number of colors in the class. */
+       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;
 
 #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 */
-
+#if 0
 static void check_border_list(struct list_head *head)
 {
   border_t *x;
@@ -191,7 +86,7 @@ static void check_heads(be_chordal_env_t *env)
     check_border_list(ent->value);
   }
 }
-
+#endif
 
 /**
  * Add an interval border to the list of a block's list
@@ -218,7 +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));
+               memset(def, 0, sizeof(*def));
                b->other_end = def;
                def->other_end = b;
 
@@ -229,8 +124,8 @@ static INLINE border_t *border_add(be_chordal_env_t *env, struct list_head *head
                 */
                set_irn_link(irn, def);
 
-               b->magic = BORDER_FOURCC;
-               def->magic = BORDER_FOURCC;
+               DEBUG_ONLY(b->magic = BORDER_FOURCC);
+               DEBUG_ONLY(def->magic = BORDER_FOURCC);
        }
 
        /*
@@ -250,16 +145,550 @@ 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->session_env->main_env->arch_env, irn, arch_pos_make_out(0), env->cls);
+       return arch_irn_has_reg_class(env->birg->main_env->arch_env, irn, -1, env->cls);
+       // return arch_irn_consider_in_reg_alloc(env->birg->main_env->arch_env, env->cls, irn);
+}
+
+#define has_limited_constr(req, irn) \
+       (arch_get_register_req(arch_env, (req), irn, -1) && (req)->type == arch_register_req_type_limited)
+
+static int get_next_free_reg(const be_chordal_alloc_env_t *alloc_env, bitset_t *colors)
+{
+       bitset_t *tmp = alloc_env->tmp_colors;
+       bitset_copy(tmp, colors);
+       bitset_or(tmp, alloc_env->chordal_env->ignore_colors);
+       return bitset_next_clear(tmp, 0);
+}
+
+static bitset_t *get_decisive_partner_regs(bitset_t *bs, const be_operand_t *o1, const be_operand_t *o2)
+{
+       bitset_t *res = bs;
+
+       if(!o1) {
+               bitset_copy(bs, o2->regs);
+               return bs;
+       }
+
+       if(!o2) {
+               bitset_copy(bs, o1->regs);
+               return bs;
+       }
+
+       assert(o1->req->cls == o2->req->cls || ! o1->req->cls || ! o2->req->cls);
+
+       if(bitset_contains(o1->regs, o2->regs))
+               bitset_copy(bs, o1->regs);
+       else if(bitset_contains(o2->regs, o1->regs))
+               bitset_copy(bs, o2->regs);
+       else
+               res = NULL;
+
+       return res;
+}
+
+static be_insn_t *chordal_scan_insn(be_chordal_env_t *env, ir_node *irn)
+{
+       be_insn_env_t ie;
+
+       ie.ignore_colors = env->ignore_colors;
+       ie.aenv          = env->birg->main_env->arch_env;
+       ie.obst          = &env->obst;
+       ie.cls           = env->cls;
+       return be_scan_insn(&ie, irn);
+}
+
+static ir_node *prepare_constr_insn(be_chordal_env_t *env, ir_node *irn)
+{
+       const arch_env_t *aenv = env->birg->main_env->arch_env;
+       bitset_t *tmp          = bitset_alloca(env->cls->n_regs);
+       bitset_t *def_constr   = bitset_alloca(env->cls->n_regs);
+       ir_node *bl            = get_nodes_block(irn);
+       be_lv_t *lv            = env->birg->lv;
+
+       be_insn_t *insn;
+       int i, j;
+
+       for (i = get_irn_arity(irn) - 1; i >= 0; --i) {
+               ir_node *op = get_irn_n(irn, i);
+               ir_node *copy;
+               const arch_register_t *reg;
+               const arch_register_req_t *req;
+
+               if (arch_get_irn_reg_class(aenv, irn, i) != env->cls)
+                       continue;
+
+               reg = arch_get_irn_register(aenv, op);
+
+               if (reg == NULL || !arch_register_type_is(reg, ignore))
+                       continue;
+               if(arch_register_type_is(reg, joker))
+                       continue;
+
+               req = arch_get_register_req(aenv, irn, i);
+               if (!arch_register_req_is(req, limited))
+                       continue;
+
+               if (rbitset_is_set(req->limited, reg->index))
+                       continue;
+
+               copy = be_new_Copy(env->cls, env->irg, bl, op);
+               be_stat_ev("constr_copy", 1);
+
+               sched_add_before(irn, copy);
+               set_irn_n(irn, i, copy);
+               DBG((env->dbg, LEVEL_3, "inserting ignore arg copy %+F for %+F pos %d\n", copy, irn, i));
+       }
+
+    insn = chordal_scan_insn(env, irn);
+
+       if(!insn->has_constraints)
+               goto end;
+
+       /* insert copies for nodes that occur constrained more than once. */
+       for(i = insn->use_start; i < insn->n_ops; ++i) {
+               be_operand_t *op = &insn->ops[i];
+
+               if(!op->has_constraints)
+                       continue;
+
+               for(j = i + 1; j < insn->n_ops; ++j) {
+                       ir_node *copy;
+                       be_operand_t *a_op = &insn->ops[j];
+
+                       if(a_op->carrier != op->carrier || !a_op->has_constraints)
+                               continue;
+
+                       copy = be_new_Copy(env->cls, env->irg, bl, op->carrier);
+                       be_stat_ev("constr_copy", 1);
+
+                       sched_add_before(insn->irn, copy);
+                       set_irn_n(insn->irn, a_op->pos, copy);
+                       DBG((env->dbg, LEVEL_3, "inserting multiple constr copy %+F for %+F pos %d\n", copy, insn->irn, a_op->pos));
+               }
+       }
+
+       /* collect all registers occuring in out constraints. */
+       for(i = 0; i < insn->use_start; ++i) {
+               be_operand_t *op = &insn->ops[i];
+               if(op->has_constraints)
+                       bitset_or(def_constr, op->regs);
+       }
+
+       /*
+               insert copies for all constrained arguments living through the node
+               and being constrained to a register which also occurs in out constraints.
+       */
+       for(i = insn->use_start; i < insn->n_ops; ++i) {
+               ir_node *copy;
+               be_operand_t *op = &insn->ops[i];
+
+               bitset_copy(tmp, op->regs);
+               bitset_and(tmp, def_constr);
+
+               /*
+                       Check, if
+                       1) the operand is constrained.
+                       2) lives through the node.
+                       3) is constrained to a register occuring in out constraints.
+               */
+               if(!op->has_constraints ||
+                               !values_interfere(lv, insn->irn, op->carrier) ||
+                               bitset_popcnt(tmp) == 0)
+                       continue;
+
+               /*
+                  only create the copy if the operand is no copy.
+                  this is necessary since the assure constraints phase inserts
+                  Copies and Keeps for operands which must be different from the results.
+                  Additional copies here would destroy this.
+                */
+               if(be_is_Copy(op->carrier))
+                       continue;
+
+               copy = be_new_Copy(env->cls, env->irg, bl, op->carrier);
+
+               sched_add_before(insn->irn, copy);
+               set_irn_n(insn->irn, op->pos, copy);
+               DBG((env->dbg, LEVEL_3, "inserting constr copy %+F for %+F pos %d\n", copy, insn->irn, op->pos));
+               be_liveness_update(lv, op->carrier);
+       }
+
+end:
+       obstack_free(&env->obst, insn);
+       return insn->next_insn;
+}
+
+static void pre_spill_prepare_constr_walker(ir_node *bl, void *data)
+{
+       be_chordal_env_t *env = data;
+       ir_node *irn;
+       for(irn = sched_first(bl); !sched_is_end(irn);) {
+               irn = prepare_constr_insn(env, irn);
+       }
+}
+
+void be_pre_spill_prepare_constr(be_chordal_env_t *cenv) {
+       irg_block_walk_graph(cenv->irg, pre_spill_prepare_constr_walker, NULL, (void *) cenv);
+}
+
+static void pair_up_operands(const be_chordal_alloc_env_t *alloc_env, be_insn_t *insn)
+{
+       const be_chordal_env_t *env = alloc_env->chordal_env;
+
+       int n_uses   = be_insn_n_uses(insn);
+       int n_defs   = be_insn_n_defs(insn);
+       bitset_t *bs = bitset_alloca(env->cls->n_regs);
+       int *pairing = alloca(MAX(n_defs, n_uses) * sizeof(pairing[0]));
+       be_lv_t *lv  = env->birg->lv;
+
+       int i, j;
+
+       /*
+               For each out operand, try to find an in operand which can be assigned the
+               same register as the out operand.
+       */
+       for (j = 0; j < insn->use_start; ++j) {
+               int smallest         = -1;
+               int smallest_n_regs  = 2 * env->cls->n_regs + 1;
+               be_operand_t *out_op = &insn->ops[j];
+
+               /* Try to find an in operand which has ... */
+               for(i = insn->use_start; i < insn->n_ops; ++i) {
+                       int n_total;
+                       const be_operand_t *op = &insn->ops[i];
+
+                       if (op->partner != NULL)
+                               continue;
+                       if (values_interfere(lv, op->irn, op->carrier))
+                               continue;
+
+                       bitset_clear_all(bs);
+                       bitset_copy(bs, op->regs);
+                       bitset_and(bs, out_op->regs);
+                       n_total = bitset_popcnt(op->regs) + bitset_popcnt(out_op->regs);
+
+                       if (bitset_popcnt(bs) > 0 && n_total < smallest_n_regs) {
+                               smallest = i;
+                               smallest_n_regs = n_total;
+                       }
+               }
+
+               if (smallest >= 0) {
+                       be_operand_t *partner = &insn->ops[smallest];
+                       out_op->partner  = partner;
+                       partner->partner = out_op;
+               }
+       }
+}
+
+
+static ir_node *pre_process_constraints(be_chordal_alloc_env_t *alloc_env,
+                                        be_insn_t **the_insn)
+{
+       be_chordal_env_t *env       = alloc_env->chordal_env;
+       const arch_env_t *aenv      = env->birg->main_env->arch_env;
+       be_insn_t *insn             = *the_insn;
+       ir_node *perm               = NULL;
+       bitset_t *out_constr        = bitset_alloca(env->cls->n_regs);
+       const ir_edge_t *edge;
+       int i;
+
+       assert(insn->has_constraints && "only do this for constrained nodes");
+
+       /*
+               Collect all registers that occur in output constraints.
+               This is necessary, since if the insn has one of these as an input constraint
+               and the corresponding operand interferes with the insn, the operand must
+               be copied.
+       */
+       for(i = 0; i < insn->use_start; ++i) {
+               be_operand_t *op = &insn->ops[i];
+               if(op->has_constraints)
+                       bitset_or(out_constr, op->regs);
+       }
+
+       /*
+               Make the Perm, recompute liveness and re-scan the insn since the
+               in operands are now the Projs of the Perm.
+       */
+       perm = insert_Perm_after(env->birg, env->cls, sched_prev(insn->irn));
+
+       /* Registers are propagated by insert_Perm_after(). Clean them here! */
+       if(perm == NULL)
+               return NULL;
+
+       be_stat_ev("constr_perm", get_irn_arity(perm));
+       foreach_out_edge(perm, edge) {
+               ir_node *proj = get_edge_src_irn(edge);
+               arch_set_irn_register(aenv, proj, NULL);
+       }
+
+       /*
+               We also have to re-build the insn since the input operands are now the Projs of
+               the Perm. Recomputing liveness is also a good idea if a Perm is inserted, since
+               the live sets may change.
+       */
+       // be_liveness_recompute(lv);
+       obstack_free(&env->obst, insn);
+       *the_insn = insn = chordal_scan_insn(env, insn->irn);
+
+       /*
+               Copy the input constraints of the insn to the Perm as output
+               constraints. Succeeding phases (coalescing) will need that.
+       */
+       for(i = insn->use_start; i < insn->n_ops; ++i) {
+               be_operand_t *op = &insn->ops[i];
+               ir_node *proj = op->carrier;
+               /*
+                       Note that the predecessor must not be a Proj of the Perm,
+                       since ignore-nodes are not Perm'ed.
+               */
+               if(op->has_constraints &&  is_Proj(proj) && get_Proj_pred(proj) == perm) {
+                       be_set_constr_limited(perm, BE_OUT_POS(get_Proj_proj(proj)), op->req);
+               }
+       }
+
+       return perm;
+}
+
+static ir_node *handle_constraints(be_chordal_alloc_env_t *alloc_env, ir_node *irn, int *silent)
+{
+       const arch_env_t *aenv;
+       int n_regs;
+       bitset_t *bs;
+       ir_node **alloc_nodes;
+       hungarian_problem_t *bp;
+       int *assignment;
+       pmap *partners;
+       int i, n_alloc;
+       long col;
+       const ir_edge_t *edge;
+       ir_node *perm = NULL;
+       int match_res, cost;
+       be_chordal_env_t *env  = alloc_env->chordal_env;
+       void *base             = obstack_base(&env->obst);
+       be_insn_t *insn        = chordal_scan_insn(env, irn);
+       ir_node *res           = insn->next_insn;
+       int be_silent          = *silent;
+       be_lv_t *lv            = env->birg->lv;
+
+       if(insn->pre_colored) {
+               int i;
+               for(i = 0; i < insn->use_start; ++i)
+                       pset_insert_ptr(alloc_env->pre_colored, insn->ops[i].carrier);
+       }
+
+       /*
+               If the current node is a barrier toggle the silent flag.
+               If we are in the start block, we are ought to be silent at the beginning,
+               so the toggling activates the constraint handling but skips the barrier.
+               If we are in the end block we handle the in requirements of the barrier
+               and set the rest to silent.
+       */
+       if(be_is_Barrier(irn))
+               *silent = !*silent;
+
+       if(be_silent)
+               goto end;
+
+       /*
+               Perms inserted before the constraint handling phase are considered to be
+               correctly precolored. These Perms arise during the ABI handling phase.
+       */
+       if(!insn->has_constraints)
+               goto end;
+
+       aenv        = env->birg->main_env->arch_env;
+       n_regs      = env->cls->n_regs;
+       bs          = bitset_alloca(n_regs);
+       alloc_nodes = alloca(n_regs * sizeof(alloc_nodes[0]));
+       bp          = hungarian_new(n_regs, n_regs, 2, HUNGARIAN_MATCH_PERFECT);
+       // bipartite_t *bp        = bipartite_new(n_regs, n_regs);
+       assignment  = alloca(n_regs * sizeof(assignment[0]));
+       partners    = pmap_create();
+
+       /*
+               prepare the constraint handling of this node.
+               Perms are constructed and Copies are created for constrained values
+               interfering with the instruction.
+       */
+       perm = pre_process_constraints(alloc_env, &insn);
+
+       /* find suitable in operands to the out operands of the node. */
+       pair_up_operands(alloc_env, insn);
+
+       /*
+               look at the in/out operands and add each operand (and its possible partner)
+               to a bipartite graph (left: nodes with partners, right: admissible colors).
+       */
+       for(i = 0, n_alloc = 0; i < insn->n_ops; ++i) {
+               be_operand_t *op = &insn->ops[i];
+
+               /*
+                       If the operand has no partner or the partner has not been marked
+                       for allocation, determine the admissible registers and mark it
+                       for allocation by associating the node and its partner with the
+                       set of admissible registers via a bipartite graph.
+               */
+               if(!op->partner || !pmap_contains(partners, op->partner->carrier)) {
+
+                       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, op->partner ? op->partner->carrier : NULL));
+
+                       bitset_clear_all(bs);
+                       get_decisive_partner_regs(bs, op, op->partner);
+
+                       DBG((dbg, LEVEL_2, "\tallowed registers for %+F: %B\n", op->carrier, bs));
+
+                       bitset_foreach(bs, col) {
+                               hungarian_add(bp, n_alloc, col, 1);
+                               // bipartite_add(bp, n_alloc, col);
+                       }
+
+                       n_alloc++;
+               }
+       }
+
+       /*
+               Put all nodes which live through the constrained instruction also to the
+               allocation bipartite graph. They are considered unconstrained.
+       */
+       if(perm != NULL) {
+               foreach_out_edge(perm, edge) {
+                       ir_node *proj = get_edge_src_irn(edge);
+
+                       assert(is_Proj(proj));
+
+                       if(!values_interfere(lv, proj, irn) || pmap_contains(partners, proj))
+                               continue;
+
+                       assert(n_alloc < n_regs);
+                       alloc_nodes[n_alloc] = proj;
+                       pmap_insert(partners, proj, NULL);
+
+                       bitset_clear_all(bs);
+                       arch_put_non_ignore_regs(aenv, env->cls, bs);
+                       bitset_andnot(bs, env->ignore_colors);
+                       bitset_foreach(bs, col) {
+                               hungarian_add(bp, n_alloc, col, 1);
+                               // bipartite_add(bp, n_alloc, col);
+                       }
+
+                       n_alloc++;
+               }
+       }
+
+       /* Compute a valid register allocation. */
+       hungarian_prepare_cost_matrix(bp, HUNGARIAN_MODE_MAXIMIZE_UTIL);
+       match_res = hungarian_solve(bp, assignment, &cost, 1);
+       assert(match_res == 0 && "matching failed");
+       //bipartite_matching(bp, assignment);
+
+       /* Assign colors obtained from the matching. */
+       for(i = 0; i < n_alloc; ++i) {
+               const arch_register_t *reg;
+               ir_node *nodes[2];
+               int j;
+
+               assert(assignment[i] >= 0 && "there must have been a register assigned");
+               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);
+                       (void) pset_hinsert_ptr(alloc_env->pre_colored, nodes[j]);
+                       DBG((dbg, LEVEL_2, "\tsetting %+F to register %s\n", nodes[j], reg->name));
+               }
+       }
+
+       /* Allocate the non-constrained Projs of the Perm. */
+       if(perm != NULL) {
+               bitset_clear_all(bs);
+
+               /* Put the colors of all Projs in a bitset. */
+               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);
+               }
+
+               /* Assign the not yet assigned Projs of the Perm a suitable color. */
+               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 = get_next_free_reg(alloc_env, bs);
+                               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));
+                       }
+               }
+       }
+
+       //bipartite_free(bp);
+       hungarian_free(bp);
+       pmap_destroy(partners);
+
+end:
+       obstack_free(&env->obst, base);
+       return res;
+}
+
+/**
+ * Handle constraint nodes in each basic block.
+ * handle_constraints() 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().
+ */
+static void constraints(ir_node *bl, void *data)
+{
+       be_chordal_alloc_env_t *env = data;
+
+       /*
+               Start silent in the start block.
+               The silence remains until the first barrier is seen.
+               Each other block is begun loud.
+       */
+       int silent                  = bl == get_irg_start_block(get_irn_irg(bl));
+       ir_node *irn;
+
+       /*
+               If the block is the start block search the barrier and
+               start handling constraints from there.
+       */
+
+       for(irn = sched_first(bl); !sched_is_end(irn);) {
+               irn = handle_constraints(env, irn, &silent);
+       }
 }
 
 /**
@@ -278,16 +707,18 @@ 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;
        ir_node *irn;
+       be_lv_t *lv                       = env->birg->lv;
 
        int i, n;
        unsigned step = 0;
        unsigned pressure = 0;
        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());
+       pset *live_in  = be_lv_pset_put_in(lv, block, pset_new_ptr_default());
+       pset *live_end = be_lv_pset_put_end(lv, block, pset_new_ptr_default());
 
        DBG((dbg, LEVEL_1, "Computing pressure in block %+F\n", block));
        bitset_clear_all(live);
@@ -295,18 +726,19 @@ 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);
 
        /*
         * Make final uses of all values live out of the block.
         * 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))
+       foreach_pset(live_end, irn) {
+               if(has_reg_class(env, irn)) {
+                       DBG((dbg, LEVEL_3, "\tMaking live: %+F/%d\n", irn, get_irn_idx(irn)));
+                       bitset_set(live, get_irn_idx(irn));
                        border_use(irn, step, 0);
+               }
        }
        ++step;
 
@@ -316,23 +748,17 @@ static void pressure(ir_node *block, void *env_ptr)
         */
        sched_foreach_reverse(block, irn) {
                DBG((dbg, LEVEL_1, "\tinsn: %+F, pressure: %d\n", irn, pressure));
-               DBG((dbg, LEVEL_2, "\tlive: %b\n", live));
+               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);
+                       int nr = get_irn_idx(irn);
 
                        bitset_clear(live, nr);
                        border_def(irn, step, 1);
-
-#ifdef BUILD_GRAPH
-                       bitset_foreach(live, elm)
-                               add_if(env, nr, (int) elm);
-#endif
                }
 
                /*
@@ -343,14 +769,16 @@ static void pressure(ir_node *block, void *env_ptr)
                                ir_node *op = get_irn_n(irn, i);
 
                                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));
+                                       int nr = get_irn_idx(op);
+                                       const char *msg = "-";
 
                                        if(!bitset_is_set(live, nr)) {
                                                border_use(op, step, 1);
                                                bitset_set(live, nr);
+                                               msg = "X";
                                        }
+
+                                       DBG((dbg, LEVEL_4, "\t\t%s pos: %d, use: %+F\n", msg, i, op));
                                }
                        }
                }
@@ -360,46 +788,45 @@ 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)) {
+       foreach_pset(live_in, irn) {
                if(has_reg_class(env, irn)) {
 
                        /* Mark the value live in. */
-                       bitset_set(live, get_irn_graph_nr(irn));
+                       bitset_set(live, get_irn_idx(irn));
 
                        /* Add the def */
                        border_def(irn, step, 0);
                }
        }
 
-
-  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;
-       bitset_t *live = env->live;
-       bitset_t *colors = env->colors;
-       bitset_t *in_colors = env->in_colors;
-  const arch_env_t *arch_env = env->session_env->main_env->arch_env;
+       be_chordal_alloc_env_t *alloc_env = env_ptr;
+       be_chordal_env_t *env       = alloc_env->chordal_env;
+       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->birg->main_env->arch_env;
+       struct list_head *head      = get_block_border_head(env, block);
+       be_lv_t *lv                 = env->birg->lv;
+       pset *live_in               = be_lv_pset_put_in(lv, block, pset_new_ptr_default());
 
        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());
 
-
-
-       bitset_clear_all(live);
        bitset_clear_all(colors);
+       bitset_clear_all(live);
        bitset_clear_all(in_colors);
 
        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 %+F/%d\n", b->is_def ? "def" : "use",
-                                       b->irn, get_irn_graph_nr(b->irn)));
+                                       b->irn, get_irn_idx(b->irn)));
        }
 
        /*
@@ -407,20 +834,22 @@ static void assign(ir_node *block, void *env_ptr)
         * Since their colors have already been assigned (The dominators were
         * allocated before), we have to mark their colors as used also.
         */
-       for(irn = pset_first(live_in); irn; irn = pset_next(live_in)) {
+       foreach_pset(live_in, irn) {
                if(has_reg_class(env, irn)) {
-      const arch_register_t *reg = arch_get_irn_register(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);
 
+                       DBG((dbg, LEVEL_4, "%+F has reg %s\n", irn, reg->name));
+
                        /* Mark the color of the live in value as used. */
                        bitset_set(colors, col);
                        bitset_set(in_colors, col);
 
                        /* Mark the value live in. */
-                       bitset_set(live, get_irn_graph_nr(irn));
+                       bitset_set(live, get_irn_idx(irn));
                }
        }
 
@@ -431,190 +860,116 @@ static void assign(ir_node *block, void *env_ptr)
         */
        list_for_each_entry_reverse(border_t, b, head, list) {
                ir_node *irn = b->irn;
-               int nr = get_irn_graph_nr(irn);
+               int nr       = get_irn_idx(irn);
+               int ignore   = arch_irn_is(arch_env, irn, ignore);
 
                /*
                 * Assign a color, if it is a local def. Global defs already have a
                 * color.
                 */
-               if(b->is_def && !is_live_in(block, irn)) {
-      const arch_register_t *reg;
+               if(b->is_def && !be_is_live_in(lv, block, irn)) {
+                       const arch_register_t *reg;
                        int col = NO_COLOR;
 
-                       DBG((dbg, LEVEL_4, "\tcolors in use: %b\n", colors));
+                       if(ignore || 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");
+                       } else {
+                               col = get_next_free_reg(alloc_env, colors);
+                               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");
+                               assert(!arch_register_type_is(reg, ignore) && "Must not assign ignore register");
+                       }
+
+                       bitset_set(colors, col);
+                       arch_set_irn_register(arch_env, irn, reg);
 
-      col = bitset_next_clear(colors, 0);
-      reg = arch_register_for_index(env->cls, col);
+                       DBG((dbg, LEVEL_1, "\tassigning register %s(%d) to %+F\n", arch_register_get_name(reg), col, irn));
 
-      assert(arch_get_irn_register(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");
-
-                       bitset_set(colors, col);
                        bitset_set(live, nr);
-
-                       arch_set_irn_register(arch_env, irn, 0, reg);
-                       DBG((dbg, LEVEL_1, "\tassigning register %s(%d) to %+F\n",
-            arch_register_get_name(reg), col, irn));
                }
 
                /* Clear the color upon a use. */
                else if(!b->is_def) {
-      const arch_register_t *reg = arch_get_irn_register(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);
-                       assert(bitset_is_set(live, nr) && "Cannot have a non live use");
+                       col = arch_register_get_index(reg);
+#ifndef NDEBUG
+                       if(!arch_register_type_is(reg, ignore)) {
+                               assert(bitset_is_set(live, nr) && "Cannot have a non live use");
+                       }
+#endif
 
                        bitset_clear(colors, col);
                        bitset_clear(live, nr);
                }
        }
 
-  del_pset(live_in);
-}
-
-void be_ra_chordal_init(void)
-{
-       dbg = firm_dbg_register(DBG_CHORDAL);
-       firm_dbg_set_mask(dbg, DBG_LEVEL);
+       del_pset(live_in);
 }
 
-be_chordal_env_t *be_ra_chordal(
-    const be_main_session_env_t *session,
-    const arch_register_class_t *cls)
+void be_ra_chordal_color(be_chordal_env_t *chordal_env)
 {
-  ir_graph *irg = session->irg;
-       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));
-
-       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
+       be_chordal_alloc_env_t env;
+       char buf[256];
+       be_irg_t *birg = chordal_env->birg;
+       const arch_register_class_t *cls = chordal_env->cls;
+
+       int colors_n          = arch_register_class_n_regs(cls);
+       ir_graph *irg         = chordal_env->irg;
+       int allocatable_regs  = colors_n - be_put_ignore_regs(birg, cls, NULL);
+
+       /* some special classes contain only ignore regs, no work to be done */
+       if(allocatable_regs == 0)
+               return;
+
+       be_assure_dom_front(birg);
+       be_assure_liveness(birg);
+       assure_doms(irg);
+
+       env.chordal_env   = chordal_env;
+       env.colors_n      = colors_n;
+       env.colors        = bitset_alloca(colors_n);
+       env.tmp_colors    = bitset_alloca(colors_n);
+       env.in_colors     = bitset_alloca(colors_n);
+       env.pre_colored   = pset_new_ptr_default();
+
+       /* Handle register targeting constraints */
+       dom_tree_walk_irg(irg, constraints, NULL, &env);
+
+       if(chordal_env->opts->dump_flags & BE_CH_DUMP_CONSTR) {
+               snprintf(buf, sizeof(buf), "-%s-constr", chordal_env->cls->name);
+               be_dump(chordal_env->irg, buf, dump_ir_block_graph_sched);
+       }
 
-  env->session_env = session;
-       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->border_heads = pmap_create();
+       env.live = bitset_malloc(get_irg_last_idx(chordal_env->irg));
 
        /* 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
-
-#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);
-
-       draw_interval_tree(&draw_chordal_def_opts, env, plotter, arch_env, cls);
-       plotter_free(plotter);
+       dom_tree_walk_irg(irg, assign, NULL, &env);
+
+       if(chordal_env->opts->dump_flags & BE_CH_DUMP_TREE_INTV) {
+               plotter_t *plotter;
+               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, 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 = chordal_env->session_env->main_env->arch_env;
-       struct obstack ob;
-       pmap_entry *pme;
-       ir_node **nodes, *n1, *n2;
-       int i, o;
-
-       /* 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);
-               if (!arch_reg_is_allocatable(arch_env, n1, arch_pos_make_out(0), n1_reg)) {
-                       DBG((dbg, 0, "Register assigned to %+F is not allowed\n", n1));
-                       assert(0 && "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);
-                       if (nodes_interfere(chordal_env, n1, n2) && n1_reg == n2_reg) {
-                               DBG((dbg, 0, "Values %+F and %+F interfere and have the same regiseter assigned\n", n1, n2));
-                               assert(0 && "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);
+       bitset_free(env.live);
+       del_pset(env.pre_colored);
 }
 
-
-
-int nodes_interfere(const be_chordal_env_t *env, const ir_node *a, const ir_node *b)
+void be_init_chordal(void)
 {
-#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;
-}
-
-set *be_ra_get_ifg_nodes(const be_chordal_env_t *env) {
-       return env->nodes;
+       FIRM_DBG_REGISTER(dbg, "firm.be.chordal.constr");
 }
 
-#endif
+BE_REGISTER_MODULE_CONSTRUCTOR(be_init_chordal);