fix bugs when exchanging nodes to projs in bepeephole
[libfirm] / ir / be / bespillbelady.c
index e8fdf8a..8479cd5 100644 (file)
@@ -1,22 +1,33 @@
-/**
- * Author:      Daniel Grund
- * Date:               20.09.2005
- * Copyright:   (c) Universitaet Karlsruhe
- * Licence:     This file protected by GPL -  GNU GENERAL PUBLIC LICENSE.
+/*
+ * Copyright (C) 1995-2007 University of Karlsruhe.  All right reserved.
+ *
+ * This file is part of libFirm.
+ *
+ * This file may be distributed and/or modified under the terms of the
+ * GNU General Public License version 2 as published by the Free Software
+ * Foundation and appearing in the file LICENSE.GPL included in the
+ * packaging of this file.
  *
+ * Licensees holding valid libFirm Professional Edition licenses may use
+ * this file in accordance with the libFirm Commercial License.
+ * Agreement provided with the Software.
+ *
+ * This file is provided AS IS with NO WARRANTY OF ANY KIND, INCLUDING THE
+ * WARRANTY OF DESIGN, MERCHANTABILITY AND FITNESS FOR A PARTICULAR
+ * PURPOSE.
+ */
+
+/**
+ * @file
+ * @brief       Beladys spillalgorithm.
+ * @author      Daniel Grund, Matthias Braun
+ * @date        20.09.2005
+ * @version     $Id$
  */
 #ifdef HAVE_CONFIG_H
 #include "config.h"
 #endif
 
-#ifdef HAVE_ALLOCA_H
-#include <alloca.h>
-#endif
-
-#ifdef HAVE_MALLOC_H
-#include <malloc.h>
-#endif
-
 #include "obst.h"
 #include "set.h"
 #include "pset.h"
 #include "irnode.h"
 #include "irmode.h"
 #include "irgwalk.h"
+#include "irloop.h"
 #include "iredges_t.h"
 #include "ircons_t.h"
 #include "irprintf.h"
+#include "xmalloc.h"
 
 #include "beutil.h"
-#include "bearch.h"
+#include "bearch_t.h"
 #include "bespillbelady.h"
-#include "beuses_t.h"
+#include "beuses.h"
 #include "besched_t.h"
 #include "beirgmod.h"
 #include "belive_t.h"
 #include "benode_t.h"
 #include "bechordal_t.h"
+#include "bespilloptions.h"
+#include "beloopana.h"
+#include "beirg_t.h"
+#include "bemodule.h"
 
 #define DBG_SPILL   1
 #define DBG_WSETS   2
 #define DBG_SLOTS  32
 #define DBG_TRACE  64
 #define DBG_WORKSET 128
-#define DEBUG_LVL 0 //(DBG_START | DBG_DECIDE | DBG_WSETS | DBG_FIX | DBG_SPILL)
 DEBUG_ONLY(static firm_dbg_module_t *dbg = NULL;)
 
-typedef struct _workset_t workset_t;
+/**
+ * An association between a node and a point in time.
+ */
+typedef struct _loc_t {
+       ir_node *irn;            /**< A node. */
+       unsigned time;           /**< A use time (see beuses.h). */
+       int      reloaded_value; /**< the value is a reloaded value */
+} loc_t;
+
+typedef struct _workset_t {
+       int len;                        /**< current length */
+       loc_t vals[0];          /**< inlined array of the values/distances in this working set */
+} workset_t;
 
 typedef struct _belady_env_t {
        struct obstack ob;
-       const be_chordal_env_t *cenv;
        const arch_env_t *arch;
        const arch_register_class_t *cls;
+       be_lv_t *lv;
+       be_loopana_t *loop_ana;
        int n_regs;                     /** number of regs in this reg-class */
 
        workset_t *ws;          /**< the main workset used while processing a block. ob-allocated */
@@ -68,18 +97,23 @@ typedef struct _belady_env_t {
        spill_env_t *senv;      /**< see bespill.h */
 } belady_env_t;
 
-struct _workset_t {
-       int len;                        /**< current length */
-       loc_t vals[0];          /**< inlined array of the values/distances in this working set */
-};
+static int loc_compare(const void *a, const void *b)
+{
+       const loc_t *p = a;
+       const loc_t *q = b;
+       return p->time - q->time;
+}
 
-void workset_print(const workset_t *w)
+/* debug helper */
+static void workset_print(const workset_t *w)
 {
        int i;
 
        for(i = 0; i < w->len; ++i) {
-               ir_fprintf(stderr, "%+F %d\n", w->vals[i].irn, w->vals[i].time);
+               ir_fprintf(stderr, "%+F %d (%d)\n", w->vals[i].irn, w->vals[i].time, w->vals[i].reloaded_value);
        }
+       /* avoid unused warning */
+       (void) workset_print;
 }
 
 /**
@@ -128,22 +162,30 @@ static INLINE void workset_bulk_fill(workset_t *workset, int count, const loc_t
  * Inserts the value @p val into the workset, iff it is not
  * already contained. The workset must not be full.
  */
-static INLINE void workset_insert(belady_env_t *env, workset_t *ws, ir_node *val) {
+static INLINE void workset_insert(belady_env_t *env, workset_t *ws,
+                                  ir_node *val, int reloaded_value)
+{
        int i;
        /* check for current regclass */
        if (!arch_irn_consider_in_reg_alloc(env->arch, env->cls, val)) {
-               DBG((dbg, DBG_WORKSET, "Dropped %+F\n", val));
+               //DBG((dbg, DBG_WORKSET, "Skipped %+F\n", val));
                return;
        }
 
        /* check if val is already contained */
-       for(i=0; i<ws->len; ++i)
-               if (ws->vals[i].irn == val)
+       for(i=0; i<ws->len; ++i) {
+               if (ws->vals[i].irn == val) {
+                       if(!ws->vals[i].reloaded_value)
+                               ws->vals[i].reloaded_value = reloaded_value;
                        return;
+               }
+       }
 
        /* insert val */
        assert(ws->len < env->n_regs && "Workset already full!");
-       ws->vals[ws->len++].irn = val;
+       ws->vals[ws->len].irn            = val;
+       ws->vals[ws->len].reloaded_value = reloaded_value;
+       ws->len++;
 }
 
 /**
@@ -208,64 +250,28 @@ static INLINE void *new_block_info(struct obstack *ob) {
        return res;
 }
 
-#define get_block_info(blk)                    ((block_info_t *)get_irn_link(blk))
-#define set_block_info(blk, info)      set_irn_link(blk, info)
+#define get_block_info(block)        ((block_info_t *)get_irn_link(block))
+#define set_block_info(block, info)  set_irn_link(block, info)
 
 /**
  * @return The distance to the next use or 0 if irn has dont_spill flag set
  */
-static INLINE unsigned get_distance(belady_env_t *env, const ir_node *from, unsigned from_step, const ir_node *def, int skip_from_uses)
+static INLINE unsigned get_distance(belady_env_t *env, ir_node *from, unsigned from_step, const ir_node *def, int skip_from_uses)
 {
+       be_next_use_t use;
        int flags = arch_irn_get_flags(env->arch, def);
-       unsigned dist = be_get_next_use(env->uses, from, from_step, def, skip_from_uses);
 
        assert(! (flags & arch_irn_flags_ignore));
 
-       /* we have to keep nonspillable nodes in the workingset */
+       use = be_get_next_use(env->uses, from, from_step, def, skip_from_uses);
+       if(USES_IS_INFINITE(use.time))
+               return USES_INFINITY;
+
+       /* We have to keep nonspillable nodes in the workingset */
        if(flags & arch_irn_flags_dont_spill)
                return 0;
 
-       return dist;
-}
-
-/**
- * Fix to remove dead nodes (especially don't spill nodes) from workset.
- */
-static void fix_dead_values(workset_t *ws, ir_node *irn) {
-       int idx;
-       ir_node *node;
-       ir_node *block = get_nodes_block(irn);
-
-       DBG((dbg, DBG_DECIDE, "fixing dead values at %+F:\n", irn));
-
-       workset_foreach(ws, node, idx) {
-               const ir_edge_t *edge;
-               int             fixme = 1;
-
-               /* skip already fixed nodes */
-               if (workset_get_time(ws, idx) == INT_MAX)
-                       continue;
-
-               /* check all users */
-               foreach_out_edge(node, edge) {
-                       ir_node *user = get_edge_src_irn(edge);
-
-                       if ((get_nodes_block(user) != block)                           ||  /* user is in a different block */
-                               (sched_is_scheduled(user) && sched_comes_after(irn, user)) ||  /* user is scheduled after irn */
-                               user == irn)                                                   /* irn is the user */
-                       {                                                                  /* => don't fix distance */
-                               fixme = 0;
-                               break;
-                       }
-               }
-
-               /* all users scheduled prior to current irn in in same block as irn -> fix */
-               if (fixme) {
-                       workset_set_time(ws, idx, INT_MAX);
-                       DBG((dbg, DBG_DECIDE, "\tfixing time for %+F to INT_MAX\n", node));
-               }
-       }
-
+       return use.time;
 }
 
 /**
@@ -295,16 +301,18 @@ static void displace(belady_env_t *env, workset_t *new_vals, int is_usage) {
 
                if (! workset_contains(ws, val)) {
                        DBG((dbg, DBG_DECIDE, "    insert %+F\n", val));
+
                        to_insert[demand++] = val;
-                       if (is_usage)
-                               be_add_reload(env->senv, val, env->instr);
-               }
-               else {
-                       assert(is_usage || "Defined value already in workset?!?");
-                       DBG((dbg, DBG_DECIDE, "    skip %+F\n", val));
+                       if (is_usage) {
+                               DBG((dbg, DBG_SPILL, "Reload %+F before %+F\n", val, env->instr));
+                               be_add_reload(env->senv, val, env->instr, env->cls, 1);
+                       }
+               } else {
+                       DBG((dbg, DBG_DECIDE, "    %+F already in workset\n", val));
+                       assert(is_usage);
                }
        }
-       DBG((dbg, DBG_DECIDE, "    demand = %d\n", demand));
+       //DBG((dbg, DBG_DECIDE, "    demand = %d\n", demand));
 
        /*
                2. Make room for at least 'demand' slots
@@ -312,24 +320,15 @@ static void displace(belady_env_t *env, workset_t *new_vals, int is_usage) {
        len         = workset_get_length(ws);
        max_allowed = env->n_regs - demand;
 
-       DBG((dbg, DBG_DECIDE, "    disposing %d values\n", ws->len - max_allowed));
-
        /* Only make more free room if we do not have enough */
        if (len > max_allowed) {
-               /* get current next-use distance */
-               for (i = 0; i < ws->len; ++i)
-                       workset_set_time(ws, i, get_distance(env, env->instr, env->instr_nr, workset_get_val(ws, i), !is_usage));
+               DBG((dbg, DBG_DECIDE, "    disposing %d values\n", ws->len - max_allowed));
 
-               /*
-                       FIX for don't spill nodes:
-                       Problem is that get_distance always returns 0 for those nodes even if they are not
-                       needed anymore (all their usages have already been visited).
-                       Even if we change this behavior, get_distance doesn't distinguish between not
-                       used anymore (dead) and live out of block.
-                       Solution: Set distances of all nodes having all their usages in schedule prior to
-                       current instruction to MAX_INT.
-               */
-               fix_dead_values(ws, env->instr);
+               /* get current next-use distance */
+               for (i = 0; i < ws->len; ++i) {
+                       unsigned dist = get_distance(env, env->instr, env->instr_nr, workset_get_val(ws, i), !is_usage);
+                       workset_set_time(ws, i, dist);
+               }
 
                /* sort entries by increasing nextuse-distance*/
                workset_sort(ws);
@@ -342,6 +341,14 @@ static void displace(belady_env_t *env, workset_t *new_vals, int is_usage) {
                for (i = max_allowed; i < ws->len; ++i) {
                        ir_node *irn = ws->vals[i].irn;
 
+                       DBG((dbg, DBG_DECIDE, "    disposing %+F (%u)\n", irn,
+                            workset_get_time(ws, i)));
+
+                       if(!USES_IS_INFINITE(ws->vals[i].time)
+                                       && !ws->vals[i].reloaded_value) {
+//                             be_add_spill(env->senv, irn, env->instr);
+                       }
+
             if (is_Phi(irn))
                 continue;
 
@@ -350,10 +357,7 @@ static void displace(belady_env_t *env, workset_t *new_vals, int is_usage) {
                                workset_t *ws_start = get_block_info(curr_bb)->ws_start;
                                workset_remove(ws_start, irn);
 
-                               DBG((dbg, DBG_DECIDE, "    dispose %+F dumb\n", irn));
-                       }
-                       else {
-                               DBG((dbg, DBG_DECIDE, "    dispose %+F\n", irn));
+                               DBG((dbg, DBG_DECIDE, "    (and removing %+F from start workset)\n", irn));
                        }
                }
 
@@ -364,24 +368,83 @@ static void displace(belady_env_t *env, workset_t *new_vals, int is_usage) {
        /*
                3. Insert the new values into the workset
        */
-       for (i = 0; i < demand; ++i)
-               workset_insert(env, env->ws, to_insert[i]);
+       for (i = 0; i < demand; ++i) {
+               workset_insert(env, env->ws, to_insert[i], 1);
+       }
 }
 
-static void belady(ir_node *blk, void *env);
+static void belady(ir_node *block, void *env);
+
+/** Decides whether a specific node should be in the start workset or not
+ *
+ * @param env      belady environment
+ * @param first
+ * @param node     the node to test
+ * @param block    the block of the node
+ * @param loop     the loop of the node
+ */
+static loc_t to_take_or_not_to_take(belady_env_t *env, ir_node* first,
+                                           ir_node *node, ir_node *block,
+                                                                       ir_loop *loop)
+{
+       be_next_use_t next_use;
+       loc_t loc;
+       loc.time = USES_INFINITY;
+       loc.irn = node;
+       loc.reloaded_value = 0;
+       (void) block;
+
+       if (!arch_irn_consider_in_reg_alloc(env->arch, env->cls, node)) {
+               loc.time = USES_INFINITY;
+               return loc;
+       }
+
+       /* We have to keep nonspillable nodes in the workingset */
+       if(arch_irn_get_flags(env->arch, node) & arch_irn_flags_dont_spill) {
+               loc.time = 0;
+               DBG((dbg, DBG_START, "    %+F taken (dontspill node)\n", node, loc.time));
+               return loc;
+       }
+
+       next_use = be_get_next_use(env->uses, first, 0, node, 0);
+       if(USES_IS_INFINITE(next_use.time)) {
+               // the nodes marked as live in shouldn't be dead, so it must be a phi
+               assert(is_Phi(node));
+               loc.time = USES_INFINITY;
+               DBG((dbg, DBG_START, "    %+F not taken (dead)\n", node));
+               if(is_Phi(node)) {
+                       be_spill_phi(env->senv, node);
+               }
+               return loc;
+       }
+
+       loc.time = next_use.time;
+
+       if(next_use.outermost_loop >= get_loop_depth(loop)) {
+               DBG((dbg, DBG_START, "    %+F taken (%u, loop %d)\n", node, loc.time, next_use.outermost_loop));
+       } else {
+               loc.time = USES_PENDING;
+               DBG((dbg, DBG_START, "    %+F delayed (outerloopdepth %d < loopdetph %d)\n", node, next_use.outermost_loop, get_loop_depth(loop)));
+       }
+       return loc;
+}
 
 /*
  * Computes set of live-ins for each block with multiple predecessors
  * and notifies spill algorithm which phis need to be spilled
  */
-static void spill_phi_walker(ir_node *block, void *data) {
-       belady_env_t *env = data;
-       block_info_t *block_info;
-       ir_node *first, *irn;
-       loc_t loc, *starters;
-       int i, len, ws_count;
-
-       if(get_Block_n_cfgpreds(block) == 1 && get_irg_start_block(get_irn_irg(block)) != block)
+static void compute_live_ins(ir_node *block, void *data) {
+       belady_env_t  *env  = data;
+       ir_loop       *loop = get_irn_loop(block);
+       const be_lv_t *lv   = env->lv;
+       block_info_t  *block_info;
+       ir_node       *first, *irn;
+       loc_t         loc, *starters, *delayed;
+       int           i, len, ws_count;
+       int               free_slots, free_pressure_slots;
+       unsigned      pressure;
+
+       if (get_Block_n_cfgpreds(block) == 1 && get_irg_start_block(get_irn_irg(block)) != block)
                return;
 
        block_info = new_block_info(&env->ob);
@@ -389,47 +452,75 @@ static void spill_phi_walker(ir_node *block, void *data) {
 
        /* Collect all values living at start of block */
        starters = NEW_ARR_F(loc_t, 0);
-
-       /* rebuild schedule time information, because it seems to be broken */
-       sched_renumber(block);
+       delayed  = NEW_ARR_F(loc_t, 0);
 
        DBG((dbg, DBG_START, "Living at start of %+F:\n", block));
        first = sched_first(block);
+
+       /* check all Phis first */
        sched_foreach(block, irn) {
-               if(!is_Phi(irn))
+               if (! is_Phi(irn))
                        break;
-               if(!arch_irn_consider_in_reg_alloc(env->arch, env->cls, irn))
-                       continue;
 
-               loc.irn = irn;
-               loc.time = get_distance(env, first, 0, irn, 0);
-               ARR_APP1(loc_t, starters, loc);
-               DBG((dbg, DBG_START, "    %+F:\n", irn));
+               loc = to_take_or_not_to_take(env, first, irn, block, loop);
+
+               if (! USES_IS_INFINITE(loc.time)) {
+                       if (USES_IS_PENDING(loc.time))
+                               ARR_APP1(loc_t, delayed, loc);
+                       else
+                               ARR_APP1(loc_t, starters, loc);
+               }
        }
 
-       be_lv_foreach(env->cenv->lv, block, be_lv_state_in, i) {
-               ir_node *irn = be_lv_get_irn(env->cenv->lv, block, i);
-               if (!arch_irn_consider_in_reg_alloc(env->arch, env->cls, irn))
-                       continue;
+       /* check all Live-Ins */
+       be_lv_foreach(lv, block, be_lv_state_in, i) {
+               ir_node *node = be_lv_get_irn(lv, block, i);
+
+               loc = to_take_or_not_to_take(env, first, node, block, loop);
 
-               loc.irn = irn;
-               loc.time = get_distance(env, first, 0, irn, 0);
-               ARR_APP1(loc_t, starters, loc);
-               DBG((dbg, DBG_START, "    %+F:\n", irn));
+               if (! USES_IS_INFINITE(loc.time)) {
+                       if (USES_IS_PENDING(loc.time))
+                               ARR_APP1(loc_t, delayed, loc);
+                       else
+                               ARR_APP1(loc_t, starters, loc);
+               }
+       }
+
+       pressure            = be_get_loop_pressure(env->loop_ana, env->cls, loop);
+       assert(ARR_LEN(delayed) <= (signed)pressure);
+       free_slots          = env->n_regs - ARR_LEN(starters);
+       free_pressure_slots = env->n_regs - (pressure - ARR_LEN(delayed));
+       free_slots          = MIN(free_slots, free_pressure_slots);
+       /* append nodes delayed due to loop structure until start set is full */
+       for (i = 0; i < ARR_LEN(delayed) && i < free_slots; ++i) {
+               DBG((dbg, DBG_START, "    delayed %+F taken\n", delayed[i].irn));
+               ARR_APP1(loc_t, starters, delayed[i]);
+               delayed[i].irn = NULL;
        }
 
-       // Sort start values by first use
+       /* spill all delayed phis which didn't make it into start workset */
+       for ( ; i < ARR_LEN(delayed); ++i) {
+               ir_node *irn = delayed[i].irn;
+               if (irn && is_Phi(irn) && get_nodes_block(irn) == block) {
+                       DBG((dbg, DBG_START, "    spilling delayed phi %+F\n", irn));
+                       be_spill_phi(env->senv, irn);
+               }
+       }
+       DEL_ARR_F(delayed);
+
+       /* Sort start values by first use */
        qsort(starters, ARR_LEN(starters), sizeof(starters[0]), loc_compare);
 
        /* Copy the best ones from starters to start workset */
-       ws_count = MIN(ARR_LEN(starters), env->n_regs);
+       ws_count             = MIN(ARR_LEN(starters), env->n_regs);
        block_info->ws_start = new_workset(env, &env->ob);
        workset_bulk_fill(block_info->ws_start, ws_count, starters);
 
        /* The phis of this block which are not in the start set have to be spilled later. */
-       for (i = ws_count, len = ARR_LEN(starters); i < len; ++i) {
+       len = ARR_LEN(starters);
+       for (i = ws_count; i < len; ++i) {
                irn = starters[i].irn;
-               if (!is_Phi(irn) || get_nodes_block(irn) != block)
+               if (! is_Phi(irn) || get_nodes_block(irn) != block)
                        continue;
 
                be_spill_phi(env->senv, irn);
@@ -439,7 +530,7 @@ static void spill_phi_walker(ir_node *block, void *data) {
 }
 
 /**
- * Collects all values live-in at block @p blk and all phi results in this block.
+ * Collects all values live-in at block @p block and all phi results in this block.
  * Then it adds the best values (at most n_regs) to the blocks start_workset.
  * The phis among the remaining values get spilled: Introduce psudo-copies of
  *  their args to break interference and make it possible to spill them to the
@@ -478,7 +569,7 @@ static block_info_t *compute_block_start_info(belady_env_t *env, ir_node *block)
 
 
 /**
- * For the given block @p blk, decide for each values
+ * For the given block @p block, decide for each values
  * whether it is used from a register or is reloaded
  * before the use.
  */
@@ -505,7 +596,7 @@ static void belady(ir_node *block, void *data) {
        workset_copy(env, env->ws, block_info->ws_start);
        DBG((dbg, DBG_WSETS, "Start workset for %+F:\n", block));
        workset_foreach(env->ws, irn, iter)
-               DBG((dbg, DBG_WSETS, "  %+F\n", irn));
+               DBG((dbg, DBG_WSETS, "  %+F (%u)\n", irn, workset_get_time(env->ws, iter)));
 
        /* process the block from start to end */
        DBG((dbg, DBG_WSETS, "Processing...\n"));
@@ -531,18 +622,22 @@ static void belady(ir_node *block, void *data) {
                /* allocate all values _used_ by this instruction */
                workset_clear(new_vals);
                for(i = 0, arity = get_irn_arity(irn); i < arity; ++i) {
-                       workset_insert(env, new_vals, get_irn_n(irn, i));
+                       /* (note that reloaded_value is not interesting here) */
+                       workset_insert(env, new_vals, get_irn_n(irn, i), 0);
                }
                displace(env, new_vals, 1);
 
                /* allocate all values _defined_ by this instruction */
                workset_clear(new_vals);
                if (get_irn_mode(irn) == mode_T) { /* special handling for tuples and projs */
-                       ir_node *proj;
-                       for(proj=sched_next(irn); is_Proj(proj); proj=sched_next(proj))
-                               workset_insert(env, new_vals, proj);
+                       const ir_edge_t *edge;
+
+                       foreach_out_edge(irn, edge) {
+                               ir_node *proj = get_edge_src_irn(edge);
+                               workset_insert(env, new_vals, proj, 0);
+                       }
                } else {
-                       workset_insert(env, new_vals, irn);
+                       workset_insert(env, new_vals, irn, 0);
                }
                displace(env, new_vals, 0);
 
@@ -555,7 +650,7 @@ static void belady(ir_node *block, void *data) {
        block_info->processed = 1;
        DBG((dbg, DBG_WSETS, "End workset for %+F:\n", block));
        workset_foreach(block_info->ws_end, irn, iter)
-               DBG((dbg, DBG_WSETS, "  %+F\n", irn));
+               DBG((dbg, DBG_WSETS, "  %+F (%u)\n", irn, workset_get_time(block_info->ws_end, iter)));
 }
 
 /**
@@ -563,94 +658,152 @@ static void belady(ir_node *block, void *data) {
  * about the set of live-ins. Thus we must adapt the
  * live-outs to the live-ins at each block-border.
  */
-static void fix_block_borders(ir_node *blk, void *data) {
-       belady_env_t *env = data;
-       workset_t *wsb;
-       int i, max, iter, iter2;
+static void fix_block_borders(ir_node *block, void *data)
+{
+       ir_graph     *irg        = get_irn_irg(block);
+       ir_node      *startblock = get_irg_start_block(irg);
+       belady_env_t *env        = data;
+       workset_t    *start_workset;
+       int           arity;
+       int           i;
+       int           iter;
+
+       if(block == startblock)
+               return;
 
        DBG((dbg, DBG_FIX, "\n"));
-       DBG((dbg, DBG_FIX, "Fixing %+F\n", blk));
+       DBG((dbg, DBG_FIX, "Fixing %+F\n", block));
 
-       wsb = get_block_info(blk)->ws_start;
+       start_workset = get_block_info(block)->ws_start;
 
        /* process all pred blocks */
-       for (i=0, max=get_irn_arity(blk); i<max; ++i) {
-               ir_node *irnb, *irnp, *pred = get_Block_cfgpred_block(blk, i);
-               workset_t *wsp = get_block_info(pred)->ws_end;
+       arity = get_irn_arity(block);
+       for (i = 0; i < arity; ++i) {
+               ir_node   *pred             = get_Block_cfgpred_block(block, i);
+               workset_t *workset_pred_end = get_block_info(pred)->ws_end;
+               ir_node   *node;
 
                DBG((dbg, DBG_FIX, "  Pred %+F\n", pred));
 
-               workset_foreach(wsb, irnb, iter) {
-                       /* if irnb is a phi of the current block we reload
-                        * the corresponding argument, else irnb itself */
-                       if(is_Phi(irnb) && blk == get_nodes_block(irnb)) {
-                               irnb = get_irn_n(irnb, i);
+               /* spill all values not used anymore */
+               workset_foreach(workset_pred_end, node, iter) {
+                       ir_node *n2;
+                       int      iter2;
+                       int      found = 0;
+                       workset_foreach(start_workset, n2, iter2) {
+                               if(n2 == node) {
+                                       found = 1;
+                                       break;
+                               }
+                               /* note that we do not look at phi inputs, becuase the values
+                                * will be either live-end and need no spill or
+                                * they have other users in which must be somewhere else in the
+                                * workset */
+                       }
 
-                               // we might have unknowns as argument for the phi
-                               if(!arch_irn_consider_in_reg_alloc(env->arch, env->cls, irnb))
-                                       continue;
+                       if(!found && be_is_live_out(env->lv, pred, node)
+                                       && !workset_pred_end->vals[iter].reloaded_value) {
+                               ir_node *insert_point
+                                       = be_get_end_of_block_insertion_point(pred);
+                               DBG((dbg, DBG_SPILL, "Spill %+F before %+F\n", node,
+                                    insert_point));
+//                             be_add_spill(env->senv, node, insert_point);
                        }
+               }
 
-                       /* Unknowns are available everywhere */
-                       if(get_irn_opcode(irnb) == iro_Unknown)
-                               continue;
+               /* reload missing values in predecessors */
+               workset_foreach(start_workset, node, iter) {
+                       /* if node is a phi of the current block we reload
+                        * the corresponding argument, else node itself */
+                       if(is_Phi(node) && block == get_nodes_block(node)) {
+                               node = get_irn_n(node, i);
 
-                       /* check if irnb is in a register at end of pred */
-                       workset_foreach(wsp, irnp, iter2) {
-                               if (irnb == irnp)
-                                       goto next_value;
+                               /* we might have unknowns as argument for the phi */
+                               if(!arch_irn_consider_in_reg_alloc(env->arch, env->cls, node))
+                                       continue;
                        }
 
-                       /* irnb is not in memory at the end of pred, so we have to reload it */
-                       DBG((dbg, DBG_FIX, "    reload %+F\n", irnb));
-                       be_add_reload_on_edge(env->senv, irnb, blk, i);
+                       /* check if node is in a register at end of pred */
+                       if(workset_contains(workset_pred_end, node))
+                               continue;
 
-next_value:
-                       /*epsilon statement :)*/;
+                       /* node is not in memory at the end of pred -> reload it */
+                       DBG((dbg, DBG_FIX, "    reload %+F\n", node));
+                       DBG((dbg, DBG_SPILL, "Reload %+F before %+F,%d\n", node, block, i));
+                       be_add_reload_on_edge(env->senv, node, block, i, env->cls, 1);
                }
        }
 }
 
-void be_spill_belady(const be_chordal_env_t *chordal_env) {
-       be_spill_belady_spill_env(chordal_env, NULL);
+/**
+ * Do spilling for a register class on a graph using the belady heuristic.
+ * In the transformed graph, the register pressure never exceeds the number
+ * of available registers.
+ *
+ * @param birg  The backend graph
+ * @param cls   The register class to spill
+ */
+static void be_spill_belady(be_irg_t *birg, const arch_register_class_t *cls) {
+       be_spill_belady_spill_env(birg, cls, NULL);
 }
 
-void be_spill_belady_spill_env(const be_chordal_env_t *chordal_env, spill_env_t *spill_env) {
+void be_spill_belady_spill_env(be_irg_t *birg, const arch_register_class_t *cls, spill_env_t *spill_env) {
        belady_env_t env;
+       ir_graph *irg = be_get_birg_irg(birg);
+       int n_regs;
 
-       FIRM_DBG_REGISTER(dbg, "firm.be.spill.belady");
-       //firm_dbg_set_mask(dbg, DBG_START);
+       n_regs = cls->n_regs - be_put_ignore_regs(birg, cls, NULL);
+       be_liveness_assure_sets(be_assure_liveness(birg));
+
+       /* construct control flow loop tree */
+       if(! (get_irg_loopinfo_state(irg) & loopinfo_cf_consistent)) {
+               construct_cf_backedges(irg);
+       }
+
+       be_clear_links(irg);
 
        /* init belady env */
        obstack_init(&env.ob);
-       env.cenv      = chordal_env;
-       env.arch      = chordal_env->birg->main_env->arch_env;
-       env.cls       = chordal_env->cls;
-       env.n_regs    = arch_count_non_ignore_regs(env.arch, env.cls);
+       env.arch      = birg->main_env->arch_env;
+       env.cls       = cls;
+       env.lv        = be_get_birg_liveness(birg);
+       env.n_regs    = n_regs;
        env.ws        = new_workset(&env, &env.ob);
-       env.uses      = be_begin_uses(chordal_env->irg, chordal_env->lv, chordal_env->birg->main_env->arch_env, env.cls);
+       env.uses      = be_begin_uses(irg, env.lv);
+       env.loop_ana  = be_new_loop_pressure(birg);
        if(spill_env == NULL) {
-               env.senv = be_new_spill_env(chordal_env);
+               env.senv = be_new_spill_env(birg);
        } else {
                env.senv = spill_env;
        }
-       DEBUG_ONLY(be_set_spill_env_dbg_module(env.senv, dbg);)
 
-       DBG((dbg, LEVEL_1, "running on register class: %s\n", env.cls->name));
-
-       be_clear_links(chordal_env->irg);
        /* Decide which phi nodes will be spilled and place copies for them into the graph */
-       irg_block_walk_graph(chordal_env->irg, spill_phi_walker, NULL, &env);
+       irg_block_walk_graph(irg, compute_live_ins, NULL, &env);
        /* Fix high register pressure with belady algorithm */
-       irg_block_walk_graph(chordal_env->irg, NULL, belady, &env);
+       irg_block_walk_graph(irg, NULL, belady, &env);
        /* belady was block-local, fix the global flow by adding reloads on the edges */
-       irg_block_walk_graph(chordal_env->irg, fix_block_borders, NULL, &env);
+       irg_block_walk_graph(irg, fix_block_borders, NULL, &env);
+
+       be_end_uses(env.uses);
+       be_free_loop_pressure(env.loop_ana);
+       obstack_free(&env.ob, NULL);
+
        /* Insert spill/reload nodes into the graph and fix usages */
        be_insert_spills_reloads(env.senv);
 
        /* clean up */
        if(spill_env == NULL)
                be_delete_spill_env(env.senv);
-       be_end_uses(env.uses);
-       obstack_free(&env.ob, NULL);
 }
+
+void be_init_spillbelady(void)
+{
+       static be_spiller_t belady_spiller = {
+               be_spill_belady
+       };
+
+       be_register_spiller("belady", &belady_spiller);
+       FIRM_DBG_REGISTER(dbg, "firm.be.spill.belady");
+}
+
+BE_REGISTER_MODULE_CONSTRUCTOR(be_init_spillbelady);