- add comment explaining the connection betwenn the race and Follower -> Leader trans...
[libfirm] / ir / opt / combo.c
index b568b42..1701b58 100644 (file)
  * @author  Michael Beck
  * @version $Id$
  *
+ * This is a slightly enhanced version of Cliff Clicks combo algorithm
+ * - support for commutative nodes is added, Add(a,b) and Add(b,a) ARE congruent
+ * - supports all Firm direct (by a data edge) identities except Mux
+ *   (Mux can be a 2-input or 1-input identity, only 2-input is implemented yet)
+ * - supports Confirm nodes (handle them like Copies but do NOT remove them)
+ * - support for global congruences is implemented but not tested yet
+ *
  * Note further that we use the terminology from Click's work here, which is different
  * in some cases from Firm terminology.  Especially, Click's type is a
  * Firm tarval/entity, nevertheless we call it type here for "maximum compatibility".
  */
-#ifdef HAVE_CONFIG_H
-# include "config.h"
-#endif
+#include "config.h"
 
 #include <assert.h>
 
@@ -48,7 +53,9 @@
 #include "irop.h"
 #include "irouts.h"
 #include "irgmod.h"
+#include "iropt_dbg.h"
 #include "debug.h"
+#include "array_t.h"
 #include "error.h"
 
 #include "tv_t.h"
 #include "irdump.h"
 
 /* define this to check that all type translations are monotone */
-#define VERIFY_MONOTONE
+#undef VERIFY_MONOTONE
 
 /* define this to check the consistency of partitions */
 #define CHECK_PARTITIONS
 
-/* define this to disable followers (may be buggy) */
-#undef NO_FOLLOWER
-
 typedef struct node_t            node_t;
 typedef struct partition_t       partition_t;
 typedef struct opcode_key_t      opcode_key_t;
@@ -167,7 +171,9 @@ typedef struct environment_t {
        pmap            *type2id_map;   /**< The type->id map. */
        int             end_idx;        /**< -1 for local and 0 for global congruences. */
        int             lambda_input;   /**< Captured argument for lambda_partition(). */
-       int             modified;       /**< Set, if the graph was modified. */
+       char            nonstd_cond;    /**< Set, if a Condb note has a non-Cmp predecessor. */
+       char            modified;       /**< Set, if the graph was modified. */
+       char            commutative;    /**< Set, if commutation nodes should be handled specially. */
 #ifdef DEBUG_libfirm
        partition_t     *dbg_list;      /**< List of all partitions. */
 #endif
@@ -187,9 +193,15 @@ typedef void *(*what_func)(const node_t *node, environment_t *env);
 /** The debug module handle. */
 DEBUG_ONLY(static firm_dbg_module_t *dbg;)
 
+/** The what reason. */
+DEBUG_ONLY(static const char *what_reason;)
+
 /** Next partition number. */
 DEBUG_ONLY(static unsigned part_nr = 0);
 
+/** The tarval returned by Unknown nodes. */
+static tarval *tarval_UNKNOWN;
+
 /* forward */
 static node_t *identity(node_t *node);
 
@@ -216,18 +228,70 @@ static void check_partition(const partition_t *T) {
        }
 }  /* check_partition */
 
+/**
+ * check that all leader nodes in the partition have the same opcode.
+ */
+static void check_opcode(const partition_t *Z) {
+       node_t       *node;
+       opcode_key_t key;
+       int          first = 1;
+
+       list_for_each_entry(node_t, node, &Z->Leader, node_list) {
+               ir_node *irn = node->node;
+
+               if (first) {
+                       key.code   = get_irn_opcode(irn);
+                       key.mode   = get_irn_mode(irn);
+                       key.arity  = get_irn_arity(irn);
+                       key.u.proj = 0;
+                       key.u.ent  = NULL;
+
+                       switch (get_irn_opcode(irn)) {
+                       case iro_Proj:
+                               key.u.proj = get_Proj_proj(irn);
+                               break;
+                       case iro_Sel:
+                               key.u.ent = get_Sel_entity(irn);
+                               break;
+                       default:
+                               break;
+                       }
+                       first = 0;
+               } else {
+                       assert(key.code   == get_irn_opcode(irn));
+                       assert(key.mode   == get_irn_mode(irn));
+                       assert(key.arity  == get_irn_arity(irn));
+
+                       switch (get_irn_opcode(irn)) {
+                       case iro_Proj:
+                               assert(key.u.proj == get_Proj_proj(irn));
+                               break;
+                       case iro_Sel:
+                               assert(key.u.ent == get_Sel_entity(irn));
+                               break;
+                       default:
+                               break;
+                       }
+               }
+       }
+}  /* check_opcode */
+
 static void check_all_partitions(environment_t *env) {
        partition_t *P;
        node_t      *node;
 
+#ifdef DEBUG_libfirm
        for (P = env->dbg_list; P != NULL; P = P->dbg_next) {
                check_partition(P);
+               if (! P->type_is_T_or_C)
+                       check_opcode(P);
                list_for_each_entry(node_t, node, &P->Follower, node_list) {
                        node_t *leader = identity(node);
 
                        assert(leader != node && leader->part == node->part);
                }
        }
+#endif
 }
 
 /**
@@ -257,7 +321,7 @@ static void check_list(const node_t *list, const partition_t *Z) {
 #endif /* CHECK_PARTITIONS */
 
 #ifdef DEBUG_libfirm
-static INLINE lattice_elem_t get_partition_type(const partition_t *X);
+static inline lattice_elem_t get_partition_type(const partition_t *X);
 
 /**
  * Dump partition to output.
@@ -302,21 +366,21 @@ static void do_dump_list(const char *msg, const node_t *node, int ofs) {
        DB((dbg, LEVEL_3, "\n}\n"));
 
 #undef GET_LINK
-}
+}  /* do_dump_list */
 
 /**
  * Dumps a race list.
  */
 static void dump_race_list(const char *msg, const node_t *list) {
        do_dump_list(msg, list, offsetof(node_t, race_next));
-}
+}  /* dump_race_list */
 
 /**
  * Dumps a local list.
  */
 static void dump_list(const char *msg, const node_t *list) {
        do_dump_list(msg, list, offsetof(node_t, next));
-}
+}  /* dump_list */
 
 /**
  * Dump all partitions.
@@ -327,13 +391,26 @@ static void dump_all_partitions(const environment_t *env) {
        DB((dbg, LEVEL_2, "All partitions\n===============\n"));
        for (P = env->dbg_list; P != NULL; P = P->dbg_next)
                dump_partition("", P);
-}
+}  /* dump_all_partitions */
+
+/**
+ * Sump a split list.
+ */
+static void dump_split_list(const partition_t *list) {
+       const partition_t *p;
+
+       DB((dbg, LEVEL_2, "Split by %s produced = {\n", what_reason));
+       for (p = list; p != NULL; p = p->split_next)
+               DB((dbg, LEVEL_2, "part%u, ", p->nr));
+       DB((dbg, LEVEL_2, "\n}\n"));
+}  /* dump_split_list */
 
 #else
 #define dump_partition(msg, part)
 #define dump_race_list(msg, list)
 #define dump_list(msg, list)
 #define dump_all_partitions(env)
+#define dump_split_list(list)
 #endif
 
 #if defined(VERIFY_MONOTONE) && defined (DEBUG_libfirm)
@@ -357,7 +434,7 @@ static void verify_type(const lattice_elem_t old_type, const lattice_elem_t new_
                return;
        }
        panic("verify_type(): wrong translation from %+F to %+F", old_type, new_type);
-}
+}  /* verify_type */
 #else
 #define verify_type(old_type, new_type)
 #endif
@@ -398,7 +475,7 @@ static void listmap_term(listmap_t *map) {
  * @param map  the listmap
  * @param id   the id to search for
  *
- * @return the asociated listmap entry for the given id
+ * @return the associated listmap entry for the given id
  */
 static listmap_entry_t *listmap_find(listmap_t *map, void *id) {
        listmap_entry_t key, *entry;
@@ -424,7 +501,7 @@ static listmap_entry_t *listmap_find(listmap_t *map, void *id) {
  * @return a hash value for the given opcode map entry
  */
 static unsigned opcode_hash(const opcode_key_t *entry) {
-       return (entry->mode - (ir_mode *)0) * 9 + entry->code + entry->u.proj * 3 + HASH_PTR(entry->u.ent);
+       return (entry->mode - (ir_mode *)0) * 9 + entry->code + entry->u.proj * 3 + HASH_PTR(entry->u.ent) + entry->arity;
 }  /* opcode_hash */
 
 /**
@@ -471,7 +548,7 @@ static void sort_irn_outs(node_t *node) {
  *
  * @return the associated type of this node
  */
-static INLINE lattice_elem_t get_node_type(const ir_node *irn) {
+static inline lattice_elem_t get_node_type(const ir_node *irn) {
        return get_irn_node(irn)->type;
 }  /* get_node_type */
 
@@ -482,7 +559,7 @@ static INLINE lattice_elem_t get_node_type(const ir_node *irn) {
  *
  * @return the associated type of this node
  */
-static INLINE tarval *get_node_tarval(const ir_node *irn) {
+static inline tarval *get_node_tarval(const ir_node *irn) {
        lattice_elem_t type = get_node_type(irn);
 
        if (is_tarval(type.tv))
@@ -493,8 +570,9 @@ static INLINE tarval *get_node_tarval(const ir_node *irn) {
 /**
  * Add a partition to the worklist.
  */
-static INLINE void add_to_worklist(partition_t *X, environment_t *env) {
+static inline void add_to_worklist(partition_t *X, environment_t *env) {
        assert(X->on_worklist == 0);
+       DB((dbg, LEVEL_2, "Adding part%d to worklist\n", X->nr));
        X->wl_next     = env->worklist;
        X->on_worklist = 1;
        env->worklist  = X;
@@ -507,7 +585,7 @@ static INLINE void add_to_worklist(partition_t *X, environment_t *env) {
  *
  * @return a newly allocated partition
  */
-static INLINE partition_t *new_partition(environment_t *env) {
+static inline partition_t *new_partition(environment_t *env) {
        partition_t *part = obstack_alloc(&env->obst, sizeof(*part));
 
        INIT_LIST_HEAD(&part->Leader);
@@ -537,7 +615,7 @@ static INLINE partition_t *new_partition(environment_t *env) {
 /**
  * Get the first node from a partition.
  */
-static INLINE node_t *get_first_node(const partition_t *X) {
+static inline node_t *get_first_node(const partition_t *X) {
        return list_entry(X->Leader.next, node_t, node_list);
 }  /* get_first_node */
 
@@ -549,7 +627,7 @@ static INLINE node_t *get_first_node(const partition_t *X) {
  *
  * @return the type of the first element of the partition
  */
-static INLINE lattice_elem_t get_partition_type(const partition_t *X) {
+static inline lattice_elem_t get_partition_type(const partition_t *X) {
        const node_t *first = get_first_node(X);
        return first->type;
 }  /* get_partition_type */
@@ -619,6 +697,10 @@ static void create_initial_partitions(ir_node *irn, void *ctx) {
 
        if (is_Phi(irn)) {
                add_Block_phi(get_nodes_block(irn), irn);
+       } else if (is_Cond(irn)) {
+               /* check if all Cond's have a Cmp predecessor. */
+               if (get_irn_mode(irn) == mode_b && !is_Cmp(skip_Proj(get_Cond_selector(irn))))
+                       env->nonstd_cond = 1;
        }
 }  /* create_initial_partitions */
 
@@ -629,7 +711,7 @@ static void create_initial_partitions(ir_node *irn, void *ctx) {
  * @param y    a node
  * @param env  the environment
  */
-static INLINE void add_to_touched(node_t *y, environment_t *env) {
+static inline void add_to_touched(node_t *y, environment_t *env) {
        if (y->on_touched == 0) {
                partition_t *part = y->part;
 
@@ -804,12 +886,6 @@ static partition_t *split_no_followers(partition_t *Z, node_t *g, environment_t
        return Z_prime;
 }  /* split_no_followers */
 
-#ifdef NO_FOLLOWER
-
-#define split(Z, g, env) split_no_followers(*(Z), g, env)
-
-#else
-
 /**
  * Make the Follower -> Leader transition for a node.
  *
@@ -869,13 +945,18 @@ static int is_real_follower(const ir_node *irn, int input) {
                break;
        }
        case iro_Sub:
+       case iro_Shr:
+       case iro_Shl:
+       case iro_Shrs:
+       case iro_Rotl:
                if (input == 1) {
-                       /* only a Sub x,0 might be a follower */
+                       /* only a Sub x,0 / Shift x,0 might be a follower */
                        return 0;
                }
                break;
-       case iro_Or:
        case iro_Add:
+       case iro_Or:
+       case iro_Eor:
                pred = get_irn_node(get_irn_n(irn, input));
                if (is_tarval(pred->type.tv) && tarval_is_null(pred->type.tv))
                        return 0;
@@ -899,7 +980,7 @@ static int is_real_follower(const ir_node *irn, int input) {
                break;
        }
        return 1;
-}
+}  /* is_real_follower */
 
 /**
  * Do one step in the race.
@@ -1000,9 +1081,9 @@ static partition_t *split(partition_t **pX, node_t *gg, environment_t *env) {
        partition_t *X = *pX;
        partition_t *X_prime;
        list_head   tmp;
-       step_env    env1, env2, *winner;
+       step_env    senv[2];
        node_t      *g, *h, *node, *t;
-       int         max_input, transitions;
+       int         max_input, transitions, winner, shf;
        unsigned    n;
        DEBUG_ONLY(static int run = 0;)
 
@@ -1039,44 +1120,60 @@ static partition_t *split(partition_t **pX, node_t *gg, environment_t *env) {
        /* restore X.Leader */
        list_splice(&tmp, &X->Leader);
 
-       env1.initial       = g;
-       env1.unwalked      = NULL;
-       env1.walked        = NULL;
-       env1.index         = 0;
-       env1.side          = 1;
+       senv[0].initial   = g;
+       senv[0].unwalked  = NULL;
+       senv[0].walked    = NULL;
+       senv[0].index     = 0;
+       senv[0].side      = 1;
 
-       env2.initial       = h;
-       env2.unwalked      = NULL;
-       env2.walked        = NULL;
-       env2.index         = 0;
-       env2.side          = 2;
+       senv[1].initial   = h;
+       senv[1].unwalked  = NULL;
+       senv[1].walked    = NULL;
+       senv[1].index     = 0;
+       senv[1].side      = 2;
 
+       /*
+        * Some informations on the race that are not stated clearly in Click's
+        * thesis.
+        * 1) A follower stays on the side that reach him first.
+        * 2) If the other side reches a follower, if will be converted to
+        *    a leader. /This must be done after the race is over, else the
+        *    edges we are iterating on are renumbered./
+        * 3) /New leader might end up on both sides./
+        * 4) /If one side ends up with new Leaders, we must ensure that
+        *    they can split out by opcode, hence we have to put _every_
+        *    partition with new Leader nodes on the cprop list, as
+        *    opcode splitting is done by split_by() at the end of
+        *    constant propagation./
+        */
        for (;;) {
-               if (step(&env1)) {
-                       winner = &env1;
+               if (step(&senv[0])) {
+                       winner = 0;
                        break;
                }
-               if (step(&env2)) {
-                       winner = &env2;
+               if (step(&senv[1])) {
+                       winner = 1;
                        break;
                }
        }
-       assert(winner->initial == NULL);
-       assert(winner->unwalked == NULL);
+       assert(senv[winner].initial == NULL);
+       assert(senv[winner].unwalked == NULL);
 
        /* clear flags from walked/unwalked */
-       transitions  = clear_flags(env1.unwalked);
-       transitions |= clear_flags(env1.walked);
-       transitions |= clear_flags(env2.unwalked);
-       transitions |= clear_flags(env2.walked);
+       shf = winner;
+       transitions  = clear_flags(senv[0].unwalked) << shf;
+       transitions |= clear_flags(senv[0].walked)   << shf;
+       shf ^= 1;
+       transitions |= clear_flags(senv[1].unwalked) << shf;
+       transitions |= clear_flags(senv[1].walked)   << shf;
 
-       dump_race_list("winner ", winner->walked);
+       dump_race_list("winner ", senv[winner].walked);
 
        /* Move walked_{winner} to a new partition, X'. */
        X_prime   = new_partition(env);
        max_input = 0;
        n         = 0;
-       for (node = winner->walked; node != NULL; node = node->race_next) {
+       for (node = senv[winner].walked; node != NULL; node = node->race_next) {
                list_del(&node->node_list);
                node->part = X_prime;
                if (node->is_follower) {
@@ -1102,7 +1199,7 @@ static partition_t *split(partition_t **pX, node_t *gg, environment_t *env) {
        list_for_each_entry_safe(node_t, node, t, &X_prime->Follower, node_list) {
                if (identity(node) == node) {
                        follower_to_leader(node);
-                       transitions = 1;
+                       transitions |= 1;
                }
        }
 
@@ -1116,27 +1213,34 @@ static partition_t *split(partition_t **pX, node_t *gg, environment_t *env) {
         * If there where follower to leader transitions, ensure that the nodes
         * can be split out if necessary.
         */
-       if (transitions) {
-               /* place partitions on the cprop list */
-                if (X_prime->on_cprop == 0) {
+       if (transitions & 1) {
+               /* place winner partition on the cprop list */
+               if (X_prime->on_cprop == 0) {
                        X_prime->cprop_next = env->cprop;
                        env->cprop          = X_prime;
                        X_prime->on_cprop   = 1;
                }
        }
+       if (transitions & 2) {
+               /* place other partition on the cprop list */
+               if (X->on_cprop == 0) {
+                       X->cprop_next = env->cprop;
+                       env->cprop    = X;
+                       X->on_cprop   = 1;
+               }
+       }
 
        dump_partition("Now ", X);
        dump_partition("Created new ", X_prime);
 
        /* we have to ensure that the partition containing g is returned */
-       if (winner == &env2) {
+       if (winner != 0) {
                *pX = X_prime;
                return X;
        }
 
        return X_prime;
 }  /* split */
-#endif /* NO_FOLLOWER */
 
 /**
  * Returns non-zero if the i'th input of a Phi node is live.
@@ -1184,7 +1288,7 @@ static int type_is_neither_top_nor_const(const lattice_elem_t type) {
                return 0;
        }
        return 1;
-}
+}  /* type_is_neither_top_nor_const */
 
 /**
  * Collect nodes to the touched list.
@@ -1219,6 +1323,11 @@ static void collect_touched(list_head *list, int idx, environment_t *env) {
 
                        succ = edge->use;
 
+                       /* only non-commutative nodes */
+                       if (env->commutative &&
+                           (idx == 0 || idx == 1) && is_op_commutative(get_irn_op(succ)))
+                               continue;
+
                        /* ignore the "control input" for non-pinned nodes
                        if we are running in GCSE mode */
                        if (idx < end_idx && get_irn_pinned(succ) != op_pin_state_pinned)
@@ -1247,6 +1356,57 @@ static void collect_touched(list_head *list, int idx, environment_t *env) {
        }
 }  /* collect_touched */
 
+/**
+ * Collect commutative nodes to the touched list.
+ *
+ * @param list  the list which contains the nodes that must be evaluated
+ * @param env   the environment
+ */
+static void collect_commutative_touched(list_head *list, environment_t *env) {
+       node_t  *x, *y;
+
+       list_for_each_entry(node_t, x, list, node_list) {
+               int num_edges;
+
+               num_edges = get_irn_n_outs(x->node);
+
+               x->next_edge = x->n_followers + 1;
+
+               /* for all edges in x.L.def_use_{idx} */
+               while (x->next_edge <= num_edges) {
+                       const ir_def_use_edge *edge = &x->node->out[x->next_edge];
+                       ir_node               *succ;
+
+                       /* check if we have necessary edges */
+                       if (edge->pos > 1)
+                               break;
+
+                       ++x->next_edge;
+                       if (edge->pos < 0)
+                               continue;
+
+                       succ = edge->use;
+
+                       /* only commutative nodes */
+                       if (!is_op_commutative(get_irn_op(succ)))
+                               continue;
+
+                       y = get_irn_node(succ);
+                       if (is_constant_type(y->type)) {
+                               ir_opcode code = get_irn_opcode(succ);
+                               if (code == iro_Eor)
+                                       add_to_cprop(y, env);
+                       }
+
+                       /* Partitions of constants should not be split simply because their Nodes have unequal
+                          functions or incongruent inputs. */
+                       if (type_is_neither_top_nor_const(y->type)) {
+                               add_to_touched(y, env);
+                       }
+               }
+       }
+}  /* collect_commutative_touched */
+
 /**
  * Split the partitions if caused by the first entry on the worklist.
  *
@@ -1263,6 +1423,44 @@ static void cause_splits(environment_t *env) {
 
        dump_partition("Cause_split: ", X);
 
+       if (env->commutative) {
+               /* handle commutative nodes first */
+
+               /* empty the touched set: already done, just clear the list */
+               env->touched = NULL;
+
+               collect_commutative_touched(&X->Leader, env);
+               collect_commutative_touched(&X->Follower, env);
+
+               for (Z = env->touched; Z != NULL; Z = N) {
+                       node_t   *e;
+                       node_t   *touched  = Z->touched;
+                       unsigned n_touched = Z->n_touched;
+
+                       assert(Z->touched != NULL);
+
+                       /* beware, split might change Z */
+                       N = Z->touched_next;
+
+                       /* remove it from the touched set */
+                       Z->on_touched = 0;
+
+                       /* Empty local Z.touched. */
+                       for (e = touched; e != NULL; e = e->next) {
+                               assert(e->is_follower == 0);
+                               e->on_touched = 0;
+                       }
+                       Z->touched   = NULL;
+                       Z->n_touched = 0;
+
+                       if (0 < n_touched && n_touched < Z->n_leader) {
+                               DB((dbg, LEVEL_2, "Split part%d by touched\n", Z->nr));
+                               split(&Z, touched, env);
+                       } else
+                               assert(n_touched <= Z->n_leader);
+               }
+       }
+
        /* combine temporary leader and follower list */
        for (idx = -1; idx <= X->max_user_inputs; ++idx) {
                /* empty the touched set: already done, just clear the list */
@@ -1345,7 +1543,7 @@ static partition_t *split_by_what(partition_t *X, what_func What,
                S = iter->list;
 
                /* Add SPLIT( X, S ) to P. */
-               DB((dbg, LEVEL_2, "Split part%d by what\n", X->nr));
+               DB((dbg, LEVEL_2, "Split part%d by WHAT = %s\n", X->nr, what_reason));
                R = split(&X, S, env);
                R->split_next = *P;
                *P            = R;
@@ -1398,7 +1596,13 @@ static void *lambda_partition(const node_t *node, environment_t *env) {
        int     i = env->lambda_input;
 
        if (i >= get_irn_arity(node->node)) {
-               /* we are outside the allowed range */
+               /*
+                * We are outside the allowed range: This can happen even
+                * if we have split by opcode first: doing so might move Followers
+                * to Leaders and those will have a different opcode!
+                * Note that in this case the partition is on the cprop list and will be
+                * split again.
+                */
                return NULL;
        }
 
@@ -1413,6 +1617,58 @@ static void *lambda_partition(const node_t *node, environment_t *env) {
        return p->part;
 }  /* lambda_partition */
 
+/** lambda n.(n[i].partition) for commutative nodes */
+static void *lambda_commutative_partition(const node_t *node, environment_t *env) {
+       ir_node     *irn     = node->node;
+       ir_node     *skipped = skip_Proj(irn);
+       ir_node     *pred, *left, *right;
+       node_t      *p;
+       partition_t *pl, *pr;
+       int         i = env->lambda_input;
+
+       if (i >= get_irn_arity(node->node)) {
+               /*
+                * We are outside the allowed range: This can happen even
+                * if we have split by opcode first: doing so might move Followers
+                * to Leaders and those will have a different opcode!
+                * Note that in this case the partition is on the cprop list and will be
+                * split again.
+                */
+               return NULL;
+       }
+
+       /* ignore the "control input" for non-pinned nodes
+          if we are running in GCSE mode */
+       if (i < env->end_idx && get_irn_pinned(skipped) != op_pin_state_pinned)
+               return NULL;
+
+       if (i == -1) {
+               pred = get_irn_n(skipped, i);
+               p    = get_irn_node(pred);
+               return p->part;
+       }
+
+       if (is_op_commutative(get_irn_op(irn))) {
+               /* normalize partition order by returning the "smaller" on input 0,
+                  the "bigger" on input 1. */
+               left  = get_binop_left(irn);
+               pl    = get_irn_node(left)->part;
+               right = get_binop_right(irn);
+               pr    = get_irn_node(right)->part;
+
+               if (i == 0)
+                       return pl < pr ? pl : pr;
+               else
+               return pl > pr ? pl : pr;
+       } else {
+               /* a not split out Follower */
+               pred = get_irn_n(irn, i);
+               p    = get_irn_node(pred);
+
+               return p->part;
+       }
+}  /* lambda_commutative_partition */
+
 /**
  * Returns true if a type is a constant.
  */
@@ -1442,8 +1698,9 @@ static void split_by(partition_t *X, environment_t *env) {
                return;
        }
 
-       DB((dbg, LEVEL_2, "WHAT = lambda n.(n.type) on part%d\n", X->nr));
+       DEBUG_ONLY(what_reason = "lambda n.(n.type)";)
        P = split_by_what(X, lambda_type, &P, env);
+       dump_split_list(P);
 
        /* adjust the type tags, we have split partitions by type */
        for (I = P; I != NULL; I = I->split_next) {
@@ -1460,8 +1717,9 @@ static void split_by(partition_t *X, environment_t *env) {
                        if (! Y->type_is_T_or_C) {
                                partition_t *Q = NULL;
 
-                               DB((dbg, LEVEL_2, "WHAT = lambda n.(n.opcode) on part%d\n", Y->nr));
+                               DEBUG_ONLY(what_reason = "lambda n.(n.opcode)";)
                                Q = split_by_what(Y, lambda_opcode, &Q, env);
+                               dump_split_list(Q);
 
                                do {
                                        partition_t *Z = Q;
@@ -1471,6 +1729,11 @@ static void split_by(partition_t *X, environment_t *env) {
                                                const node_t *first = get_first_node(Z);
                                                int          arity  = get_irn_arity(first->node);
                                                partition_t  *R, *S;
+                                               what_func    what = lambda_partition;
+                                               DEBUG_ONLY(char buf[64];)
+
+                                               if (env->commutative && is_op_commutative(get_irn_op(first->node)))
+                                                       what = lambda_commutative_partition;
 
                                                /*
                                                 * BEWARE: during splitting by input 2 for instance we might
@@ -1487,8 +1750,10 @@ static void split_by(partition_t *X, environment_t *env) {
                                                                R = R->split_next;
                                                                if (Z_prime->n_leader > 1) {
                                                                        env->lambda_input = input;
-                                                                       DB((dbg, LEVEL_2, "WHAT = lambda n.(n[%d].partition) on part%d\n", input, Z_prime->nr));
-                                                                       S = split_by_what(Z_prime, lambda_partition, &S, env);
+                                                                       DEBUG_ONLY(snprintf(buf, sizeof(buf), "lambda n.(n[%d].partition)", input);)
+                                                                       DEBUG_ONLY(what_reason = buf;)
+                                                                       S = split_by_what(Z_prime, what, &S, env);
+                                                                       dump_split_list(S);
                                                                } else {
                                                                        Z_prime->split_next = S;
                                                                        S                   = Z_prime;
@@ -1588,10 +1853,8 @@ static void compute_Unknown(node_t *node) {
         * nodes are inputs to Conds. We check that first.
         * This is the way Frontends typically build Firm, but some optimizations
         * (cond_eval for instance) might replace them by Phib's...
-        *
-        * For now, we compute bottom here.
         */
-       node->type.tv = tarval_bottom;
+       node->type.tv = tarval_UNKNOWN;
 }  /* compute_Unknown */
 
 /**
@@ -1762,7 +2025,8 @@ static void compute_Sub(node_t *node) {
                tv = get_mode_null(mode);
 
                /* if the node was ONCE evaluated by all constants, but now
-                  this breakes AND we cat by partition a different result, switch to bottom.
+                  this breaks AND we get from the argument partitions a different
+                  result, switch to bottom.
                   This happens because initially all nodes are in the same partition ... */
                if (node->by_all_const && node->type.tv != tv)
                        tv = tarval_bottom;
@@ -1772,6 +2036,48 @@ static void compute_Sub(node_t *node) {
        }
 }  /* compute_Sub */
 
+/**
+ * (Re-)compute the type for an Eor. Special case: both nodes are congruent.
+ *
+ * @param node  the node
+ */
+static void compute_Eor(node_t *node) {
+       ir_node        *eor = node->node;
+       node_t         *l   = get_irn_node(get_Eor_left(eor));
+       node_t         *r   = get_irn_node(get_Eor_right(eor));
+       lattice_elem_t a    = l->type;
+       lattice_elem_t b    = r->type;
+       tarval         *tv;
+
+       if (a.tv == tarval_top || b.tv == tarval_top) {
+               node->type.tv = tarval_top;
+       } else if (is_con(a) && is_con(b)) {
+               if (is_tarval(a.tv) && is_tarval(b.tv)) {
+                       node->type.tv = tarval_eor(a.tv, b.tv);
+               } else if (is_tarval(a.tv) && tarval_is_null(a.tv)) {
+                       node->type = b;
+               } else if (is_tarval(b.tv) && tarval_is_null(b.tv)) {
+                       node->type = a;
+               } else {
+                       node->type.tv = tarval_bottom;
+               }
+               node->by_all_const = 1;
+       } else if (r->part == l->part) {
+               ir_mode *mode = get_irn_mode(eor);
+               tv = get_mode_null(mode);
+
+               /* if the node was ONCE evaluated by all constants, but now
+                  this breaks AND we get from the argument partitions a different
+                  result, switch to bottom.
+                  This happens because initially all nodes are in the same partition ... */
+               if (node->by_all_const && node->type.tv != tv)
+                       tv = tarval_bottom;
+               node->type.tv = tv;
+       } else {
+               node->type.tv = tarval_bottom;
+       }
+}  /* compute_Eor */
+
 /**
  * (Re-)compute the type for Cmp.
  *
@@ -1785,7 +2091,15 @@ static void compute_Cmp(node_t *node) {
        lattice_elem_t b     = r->type;
 
        if (a.tv == tarval_top || b.tv == tarval_top) {
+#ifdef WITH_UNKNOWN
+               /*
+                * Top is congruent to any other value, we can
+                * calculate the compare result.
+                */
+               node->type.tv = tarval_b_true;
+#else
                node->type.tv = tarval_top;
+#endif
        } else if (is_con(a) && is_con(b)) {
                /* both nodes are constants, we can probably do something */
                node->type.tv = tarval_b_true;
@@ -1813,7 +2127,13 @@ static void compute_Proj_Cmp(node_t *node, ir_node *cmp) {
        tarval         *tv;
 
        if (a.tv == tarval_top || b.tv == tarval_top) {
+#ifdef WITH_UNKNOWN
+               /* see above */
+               tv = new_tarval_from_long((pnc & pn_Cmp_Eq) ^ pn_Cmp_Eq, mode_b);
+               goto not_equal;
+#else
                node->type.tv = tarval_top;
+#endif
        } else if (is_con(a) && is_con(b)) {
                default_compute(node);
                node->by_all_const = 1;
@@ -1824,9 +2144,13 @@ static void compute_Proj_Cmp(node_t *node, ir_node *cmp) {
                 * NaN != NaN is defined, so we must check this here.
                 */
                tv = new_tarval_from_long(pnc & pn_Cmp_Eq, mode_b);
+#ifdef WITH_UNKNOWN
+not_equal:
+#endif
 
                /* if the node was ONCE evaluated by all constants, but now
-                  this breakes AND we cat by partition a different result, switch to bottom.
+                  this breaks AND we get from the argument partitions a different
+                  result, switch to bottom.
                   This happens because initially all nodes are in the same partition ... */
                if (node->by_all_const && node->type.tv != tv)
                        tv = tarval_bottom;
@@ -1986,18 +2310,18 @@ static void compute_Confirm(node_t *node) {
  * @param node  the node
  */
 static void compute_Max(node_t *node) {
-       ir_node        *op   = node->node;
-       node_t         *l    = get_irn_node(get_binop_left(op));
-       node_t         *r    = get_irn_node(get_binop_right(op));
-       lattice_elem_t a     = l->type;
-       lattice_elem_t b     = r->type;
+       ir_node        *op = node->node;
+       node_t         *l  = get_irn_node(get_binop_left(op));
+       node_t         *r  = get_irn_node(get_binop_right(op));
+       lattice_elem_t a   = l->type;
+       lattice_elem_t b   = r->type;
 
        if (a.tv == tarval_top || b.tv == tarval_top) {
                node->type.tv = tarval_top;
        } else if (is_con(a) && is_con(b)) {
                /* both nodes are constants, we can probably do something */
                if (a.tv == b.tv) {
-                       /* this case handles symconsts as well */
+                       /* this case handles SymConsts as well */
                        node->type = a;
                } else {
                        ir_mode *mode   = get_irn_mode(op);
@@ -2030,18 +2354,18 @@ static void compute_Max(node_t *node) {
  * @param node  the node
  */
 static void compute_Min(node_t *node) {
-       ir_node        *op   = node->node;
-       node_t         *l    = get_irn_node(get_binop_left(op));
-       node_t         *r    = get_irn_node(get_binop_right(op));
-       lattice_elem_t a     = l->type;
-       lattice_elem_t b     = r->type;
+       ir_node        *op = node->node;
+       node_t         *l  = get_irn_node(get_binop_left(op));
+       node_t         *r  = get_irn_node(get_binop_right(op));
+       lattice_elem_t a   = l->type;
+       lattice_elem_t b   = r->type;
 
        if (a.tv == tarval_top || b.tv == tarval_top) {
                node->type.tv = tarval_top;
        } else if (is_con(a) && is_con(b)) {
                /* both nodes are constants, we can probably do something */
                if (a.tv == b.tv) {
-                       /* this case handles symconsts as well */
+                       /* this case handles SymConsts as well */
                        node->type = a;
                } else {
                        ir_mode *mode   = get_irn_mode(op);
@@ -2151,8 +2475,22 @@ static node_t *identity_comm_zero_binop(node_t *node) {
        return node;
 }  /* identity_comm_zero_binop */
 
-#define identity_Add  identity_comm_zero_binop
-#define identity_Or   identity_comm_zero_binop
+/**
+ * Calculates the Identity for Shift nodes.
+ */
+static node_t *identity_shift(node_t *node) {
+       ir_node *op   = node->node;
+       node_t  *b    = get_irn_node(get_binop_right(op));
+       ir_mode *mode = get_irn_mode(b->node);
+       tarval  *zero;
+
+       /* node: no input should be tarval_top, else the binop would be also
+        * Top and not being split. */
+       zero = get_mode_null(mode);
+       if (b->type.tv == zero)
+               return get_irn_node(get_binop_left(op));
+       return node;
+}  /* identity_shift */
 
 /**
  * Calculates the Identity for Mul nodes.
@@ -2195,7 +2533,7 @@ static node_t *identity_Sub(node_t *node) {
        if (b->type.tv == get_mode_null(mode))
                return get_irn_node(get_Sub_left(sub));
        return node;
-}  /* identity_Mul */
+}  /* identity_Sub */
 
 /**
  * Calculates the Identity for And nodes.
@@ -2307,12 +2645,17 @@ static node_t *identity(node_t *node) {
        switch (get_irn_opcode(irn)) {
        case iro_Phi:
                return identity_Phi(node);
-       case iro_Add:
-               return identity_Add(node);
        case iro_Mul:
                return identity_Mul(node);
+       case iro_Add:
        case iro_Or:
-               return identity_Or(node);
+       case iro_Eor:
+               return identity_comm_zero_binop(node);
+       case iro_Shr:
+       case iro_Shl:
+       case iro_Shrs:
+       case iro_Rotl:
+               return identity_shift(node);
        case iro_And:
                return identity_And(node);
        case iro_Sub:
@@ -2355,9 +2698,8 @@ static void segregate_def_use_chain_1(const ir_node *follower, node_t *leader) {
 }  /* segregate_def_use_chain_1 */
 
 /**
- * Node follower is a (new) follower of leader, segregate Leader
- * out edges. If follower is a n-congruent Input identity, all follower
- * inputs congruent to follower are also leader.
+ * Node follower is a (new) follower segregate its Leader
+ * out edges.
  *
  * @param follower  the follower IR node
  */
@@ -2466,13 +2808,9 @@ static void propagate(environment_t *env) {
                for (x = fallen; x != NULL; x = x->next)
                        x->on_fallen = 0;
 
-#ifndef NO_FOLLOWER
                if (old_type_was_T_or_C) {
                        node_t *y, *tmp;
 
-                       if (Y->on_worklist == 0)
-                               add_to_worklist(Y, env);
-
                        /* check if some nodes will make the leader -> follower transition */
                        list_for_each_entry_safe(node_t, y, tmp, &Y->Leader, node_list) {
                                if (y->type.tv != tarval_top && ! is_con(y->type)) {
@@ -2491,7 +2829,6 @@ static void propagate(environment_t *env) {
                                }
                        }
                }
-#endif
                split_by(Y, env);
        }
 }  /* propagate */
@@ -2531,7 +2868,7 @@ static int can_exchange(ir_node *pred) {
                int i, k;
 
                /* if the predecessor block has more than one
-               reachable outputs we cannot remove the block */
+                  reachable outputs we cannot remove the block */
                k = 0;
                for (i = get_irn_n_outs(pred) - 1; i >= 0; --i) {
                        ir_node *proj = get_irn_out(pred, i);
@@ -2550,7 +2887,7 @@ static int can_exchange(ir_node *pred) {
                return 1;
        }
        return 0;
-}
+}  /* can_exchange */
 
 /**
  * Block Post-Walker, apply the analysis results on control flow by
@@ -2563,26 +2900,55 @@ static void apply_cf(ir_node *block, void *ctx) {
        ir_node       **ins, **in_X;
        ir_node       *phi, *next;
 
-       if (block == get_irg_end_block(current_ir_graph) ||
-           block == get_irg_start_block(current_ir_graph)) {
+       n = get_Block_n_cfgpreds(block);
+
+       if (node->type.tv == tarval_unreachable) {
+               env->modified = 1;
+
+               for (i = n - 1; i >= 0; --i) {
+                       ir_node *pred = get_Block_cfgpred(block, i);
+
+                       if (! is_Bad(pred)) {
+                               node_t *pred_bl = get_irn_node(get_nodes_block(skip_Proj(pred)));
+
+                               if (pred_bl->flagged == 0) {
+                                       pred_bl->flagged = 3;
+
+                                       if (pred_bl->type.tv == tarval_reachable) {
+                                               /*
+                                                * We will remove an edge from block to its pred.
+                                                * This might leave the pred block as an endless loop
+                                                */
+                                               if (! is_backedge(block, i))
+                                                       keep_alive(pred_bl->node);
+                                       }
+                               }
+                       }
+               }
+
                /* the EndBlock is always reachable even if the analysis
                   finds out the opposite :-) */
-               return;
-       }
-       if (node->type.tv == tarval_unreachable) {
-               /* mark dead blocks */
-               set_Block_dead(block);
+               if (block != get_irg_end_block(current_ir_graph)) {
+                       /* mark dead blocks */
+                       set_Block_dead(block);
+                       DB((dbg, LEVEL_1, "Removing dead %+F\n", block));
+               } else {
+                       /* the endblock is unreachable */
+                       set_irn_in(block, 0, NULL);
+               }
                return;
        }
 
-       n = get_Block_n_cfgpreds(block);
-
        if (n == 1) {
                /* only one predecessor combine */
                ir_node *pred = skip_Proj(get_Block_cfgpred(block, 0));
 
                if (can_exchange(pred)) {
-                       exchange(block, get_nodes_block(pred));
+                       ir_node *new_block = get_nodes_block(pred);
+                       DB((dbg, LEVEL_1, "Fuse %+F with %+F\n", block, new_block));
+                       DBG_OPT_COMBO(block, new_block, FS_OPT_COMBO_CF);
+                       exchange(block, new_block);
+                       node->node = new_block;
                        env->modified = 1;
                }
                return;
@@ -2596,6 +2962,24 @@ static void apply_cf(ir_node *block, void *ctx) {
 
                if (node->type.tv == tarval_reachable) {
                        in_X[k++] = pred;
+               } else {
+                       DB((dbg, LEVEL_1, "Removing dead input %d from %+F (%+F)\n", i, block, pred));
+                       if (! is_Bad(pred)) {
+                               node_t *pred_bl = get_irn_node(get_nodes_block(skip_Proj(pred)));
+
+                               if (pred_bl->flagged == 0) {
+                                       pred_bl->flagged = 3;
+
+                                       if (pred_bl->type.tv == tarval_reachable) {
+                                               /*
+                                                * We will remove an edge from block to its pred.
+                                                * This might leave the pred block as an endless loop
+                                                */
+                                               if (! is_backedge(block, i))
+                                                       keep_alive(pred_bl->node);
+                                       }
+                               }
+                       }
                }
        }
        if (k >= n)
@@ -2614,6 +2998,7 @@ static void apply_cf(ir_node *block, void *ctx) {
                        set_irn_node(c, node);
                        node->node = c;
                        DB((dbg, LEVEL_1, "%+F is replaced by %+F\n", phi, c));
+                       DBG_OPT_COMBO(phi, c, FS_OPT_COMBO_CONST);
                        exchange(phi, c);
                        env->modified = 1;
                } else {
@@ -2625,13 +3010,16 @@ static void apply_cf(ir_node *block, void *ctx) {
                                        ins[j++] = get_Phi_pred(phi, i);
                                }
                        }
-                       if (j <= 1) {
+                       if (j == 1) {
                                /* this Phi is replaced by a single predecessor */
                                ir_node *s = ins[0];
+                               node_t *phi_node = get_irn_node(phi);
 
                                node->node = s;
                                DB((dbg, LEVEL_1, "%+F is replaced by %+F because of cf change\n", phi, s));
+                               DBG_OPT_COMBO(phi, s, FS_OPT_COMBO_FOLLOWER);
                                exchange(phi, s);
+                               phi_node->node = s;
                                env->modified = 1;
                        } else {
                                set_irn_in(phi, j, ins);
@@ -2640,18 +3028,42 @@ static void apply_cf(ir_node *block, void *ctx) {
                }
        }
 
-       if (k <= 1) {
+       if (k == 1) {
                /* this Block has only one live predecessor */
                ir_node *pred = skip_Proj(in_X[0]);
 
                if (can_exchange(pred)) {
-                       exchange(block, get_nodes_block(pred));
+                       ir_node *new_block = get_nodes_block(pred);
+                       DBG_OPT_COMBO(block, new_block, FS_OPT_COMBO_CF);
+                       exchange(block, new_block);
+                       node->node = new_block;
                        env->modified = 1;
                }
        } else {
                set_irn_in(block, k, in_X);
                env->modified = 1;
        }
+}  /* apply_cf */
+
+/**
+ * Exchange a node by its leader.
+ * Beware: in rare cases the mode might be wrong here, for instance
+ * AddP(x, NULL) is a follower of x, but with different mode.
+ * Fix it here.
+ */
+static void exchange_leader(ir_node *irn, ir_node *leader) {
+       ir_mode *mode = get_irn_mode(irn);
+       if (mode != get_irn_mode(leader)) {
+               /* The conv is a no-op, so we are fre to place in
+                * either in the block of the leader OR in irn's block.
+                * Propably placing it into leaders block might reduce
+                * the number of Conv due to CSE. */
+               ir_node  *block = get_nodes_block(leader);
+               dbg_info *dbg   = get_irn_dbg_info(irn);
+
+               leader = new_rd_Conv(dbg, current_ir_graph, block, leader, mode);
+       }
+       exchange(irn, leader);
 }
 
 /**
@@ -2678,14 +3090,17 @@ static void apply_result(ir_node *irn, void *ctx) {
                        env->modified = 1;
                }
                else if (node->type.tv == tarval_unreachable) {
-                       ir_node *bad = get_irg_bad(current_ir_graph);
-
-                       /* see comment above */
-                       set_irn_node(bad, node);
-                       node->node = bad;
-                       DB((dbg, LEVEL_1, "%+F is unreachable\n", irn));
-                       exchange(irn, bad);
-                       env->modified = 1;
+                       /* don't kick away Unknown */
+                       if (! is_Unknown(irn)) {
+                               ir_node *bad = get_irg_bad(current_ir_graph);
+
+                               /* see comment above */
+                               set_irn_node(bad, node);
+                               node->node = bad;
+                               DB((dbg, LEVEL_1, "%+F is unreachable\n", irn));
+                               exchange(irn, bad);
+                               env->modified = 1;
+                       }
                }
                else if (get_irn_mode(irn) == mode_X) {
                        if (is_Proj(irn)) {
@@ -2696,11 +3111,12 @@ static void apply_result(ir_node *irn, void *ctx) {
                                        node_t *sel = get_irn_node(get_Cond_selector(cond));
 
                                        if (is_tarval(sel->type.tv) && tarval_is_constant(sel->type.tv)) {
-                                               /* Cond selector is a constant, make a Jmp */
-                                               ir_node *jmp = new_r_Jmp(current_ir_graph, block->node);
+                                               /* Cond selector is a constant and the Proj is reachable, make a Jmp */
+                                               ir_node *jmp  = new_r_Jmp(current_ir_graph, block->node);
                                                set_irn_node(jmp, node);
                                                node->node = jmp;
                                                DB((dbg, LEVEL_1, "%+F is replaced by %+F\n", irn, jmp));
+                                               DBG_OPT_COMBO(irn, jmp, FS_OPT_COMBO_CF);
                                                exchange(irn, jmp);
                                                env->modified = 1;
                                        }
@@ -2721,18 +3137,20 @@ static void apply_result(ir_node *irn, void *ctx) {
                                        set_irn_node(c, node);
                                        node->node = c;
                                        DB((dbg, LEVEL_1, "%+F is replaced by %+F\n", irn, c));
-                                       exchange(irn, c);
+                                       DBG_OPT_COMBO(irn, c, FS_OPT_COMBO_CONST);
+                                       exchange_leader(irn, c);
                                        env->modified = 1;
                                }
                        } else if (is_entity(node->type.sym.entity_p)) {
                                if (! is_SymConst(irn)) {
-                                       /* can be replaced by a Symconst */
+                                       /* can be replaced by a SymConst */
                                        ir_node *symc = new_r_SymConst(current_ir_graph, block->node, get_irn_mode(irn), node->type.sym, symconst_addr_ent);
                                        set_irn_node(symc, node);
                                        node->node = symc;
 
                                        DB((dbg, LEVEL_1, "%+F is replaced by %+F\n", irn, symc));
-                                       exchange(irn, symc);
+                                       DBG_OPT_COMBO(irn, symc, FS_OPT_COMBO_CONST);
+                                       exchange_leader(irn, symc);
                                        env->modified = 1;
                                }
                        } else if (is_Confirm(irn)) {
@@ -2742,7 +3160,11 @@ static void apply_result(ir_node *irn, void *ctx) {
 
                                if (leader != irn) {
                                        DB((dbg, LEVEL_1, "%+F from part%d is replaced by %+F\n", irn, node->part->nr, leader));
-                                       exchange(irn, leader);
+                                       if (node->is_follower)
+                                               DBG_OPT_COMBO(irn, leader, FS_OPT_COMBO_FOLLOWER);
+                                       else
+                                               DBG_OPT_COMBO(irn, leader, FS_OPT_COMBO_CONGRUENT);
+                                       exchange_leader(irn, leader);
                                        env->modified = 1;
                                }
                        }
@@ -2765,17 +3187,11 @@ static void apply_end(ir_node *end, environment_t *env) {
                ir_node *ka   = get_End_keepalive(end, i);
                node_t  *node = get_irn_node(ka);
 
-               /* Use the flagged bits to mark already visited nodes.
-                * This should not be ready but better safe than sorry. */
-               if (node->flagged == 0) {
-                       node->flagged = 3;
-
-                       if (! is_Block(ka))
-                               node = get_irn_node(get_nodes_block(ka));
+               if (! is_Block(ka))
+                       node = get_irn_node(get_nodes_block(ka));
 
-                       if (node->type.tv != tarval_unreachable)
-                               in[j++] = ka;
-               }
+               if (node->type.tv != tarval_unreachable && !is_Bad(ka))
+                       in[j++] = ka;
        }
        if (j != n) {
                set_End_keepalives(end, j, in);
@@ -2805,6 +3221,7 @@ static void set_compute_functions(void) {
        SET(Phi);
        SET(Add);
        SET(Sub);
+       SET(Eor);
        SET(SymConst);
        SET(Cmp);
        SET(Proj);
@@ -2819,11 +3236,13 @@ static void set_compute_functions(void) {
 }  /* set_compute_functions */
 
 static int dump_partition_hook(FILE *F, ir_node *n, ir_node *local) {
+#ifdef DEBUG_libfirm
        ir_node *irn = local != NULL ? local : n;
        node_t *node = get_irn_node(irn);
 
        ir_fprintf(F, "info2 : \"partition %u type %+F\"\n", node->part->nr, node->type);
        return 1;
+#endif
 }
 
 void combo(ir_graph *irg) {
@@ -2836,7 +3255,6 @@ void combo(ir_graph *irg) {
 
        /* register a debug mask */
        FIRM_DBG_REGISTER(dbg, "firm.opt.combo");
-       //firm_dbg_set_mask(dbg, SET_LEVEL_3);
 
        DB((dbg, LEVEL_1, "Doing COMBO for %+F\n", irg));
 
@@ -2852,9 +3270,12 @@ void combo(ir_graph *irg) {
        env.type2id_map    = pmap_create();
        env.end_idx        = get_opt_global_cse() ? 0 : -1;
        env.lambda_input   = 0;
+       env.nonstd_cond    = 0;
+       env.commutative    = 1;
        env.modified       = 0;
 
        assure_irg_outs(irg);
+       assure_cf_loop(irg);
 
        /* we have our own value_of function */
        set_value_of_func(get_node_tarval);
@@ -2862,11 +3283,19 @@ void combo(ir_graph *irg) {
        set_compute_functions();
        DEBUG_ONLY(part_nr = 0);
 
+       ir_reserve_resources(irg, IR_RESOURCE_IRN_LINK);
+
        /* create the initial partition and place it on the work list */
        env.initial = new_partition(&env);
        add_to_worklist(env.initial, &env);
        irg_walk_graph(irg, init_block_phis, create_initial_partitions, &env);
 
+#ifdef WITH_UNKNOWN
+       tarval_UNKNOWN = env.nonstd_cond ? tarval_bad : tarval_top;
+#else
+       tarval_UNKNOWN = tarval_bad;
+#endif
+
        /* all nodes on the initial partition have type Top */
        env.initial->type_is_T_or_C = 1;
 
@@ -2906,6 +3335,8 @@ void combo(ir_graph *irg) {
                set_irg_loopinfo_inconsistent(irg);
        }
 
+       ir_free_resources(irg, IR_RESOURCE_IRN_LINK);
+
        pmap_destroy(env.type2id_map);
        del_set(env.opcode2id_map);
        obstack_free(&env.obst, NULL);