X-Git-Url: http://nsz.repo.hu/git/?a=blobdiff_plain;f=ir%2Fopt%2Fcombo.c;h=bb00e899476417f0556911a6bc185d6c8cd0d475;hb=cceaeb0d5cf3f95f6f0b9f1aa709af320c84b1ec;hp=e30dbedbf09dff0262ca70a7ca2a6ced27b270fc;hpb=0fbcef83aa6060534172bb13e71cdadb04428806;p=libfirm

diff --git a/ir/opt/combo.c b/ir/opt/combo.c
index e30dbedbf..bb00e8994 100644
--- a/ir/opt/combo.c
+++ b/ir/opt/combo.c
@@ -1,5 +1,5 @@
 /*
- * Copyright (C) 1995-2008 University of Karlsruhe.  All right reserved.
+ * Copyright (C) 1995-2011 University of Karlsruhe.  All right reserved.
  *
  * This file is part of libFirm.
  *
@@ -28,6 +28,30 @@
  * - 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)
+ * - let Cmp nodes calculate Top like all othe data nodes: this would let
+ *   Mux nodes to calculate Unknown instead of taking the true result
+ * - let Cond(Top) always select FALSE/default: This is tricky. Nodes are only reavaluated
+ *   IFF the predecessor changed its type. Because nodes are initialized with Top
+ *   this never happens, let all Proj(Cond) be unreachable.
+ *   We avoid this condition by the same way we work around Phi: whenever a Block
+ *   node is placed on the list, place its Cond nodes (and because they are Tuple
+ *   all its Proj-nodes either on the cprop list)
+ *   Especially, this changes the meaning of Click's example:
+ *
+ *   int main() {
+ *     int x;
+ *
+ *     if (x == 2)
+ *       printf("x == 2\n");
+ *     if (x == 3)
+ *       printf("x == 3\n");
+ *   }
+ *
+ *   Would print:
+ *   x == 2
+ *   x == 3
+ *
+ *   using Click's version while is silent with our.
  * - 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
@@ -39,7 +63,6 @@
 #include <assert.h>
 
 #include "iroptimize.h"
-#include "archop.h"
 #include "irflag.h"
 #include "ircons.h"
 #include "list.h"
@@ -57,14 +80,16 @@
 #include "debug.h"
 #include "array_t.h"
 #include "error.h"
-
+#include "irnodeset.h"
+#include "irpass.h"
 #include "tv_t.h"
+#include "irtools.h"
 
 #include "irprintf.h"
 #include "irdump.h"
 
 /* define this to check that all type translations are monotone */
-#undef VERIFY_MONOTONE
+#define VERIFY_MONOTONE
 
 /* define this to check the consistency of partitions */
 #define CHECK_PARTITIONS
@@ -81,12 +106,16 @@ typedef void (*compute_func)(node_t *node);
  * An opcode map key.
  */
 struct opcode_key_t {
-	ir_opcode   code;   /**< The Firm opcode. */
+	unsigned    code;   /**< The Firm opcode. */
 	ir_mode     *mode;  /**< The mode of all nodes in the partition. */
 	int         arity;  /**< The arity of this opcode (needed for Phi etc. */
 	union {
 		long      proj;   /**< For Proj nodes, its proj number */
 		ir_entity *ent;   /**< For Sel Nodes, its entity */
+		int       intVal; /**< For Conv/Div Nodes: strict/remainderless */
+		unsigned  uintVal;/**< for Builtin: the kind */
+		ir_node   *block; /**< for Block: itself */
+		void      *ptr;   /**< generic pointer for hash/cmp */
 	} u;
 };
 
@@ -110,7 +139,7 @@ typedef struct listmap_t {
  * have to use this union.
  */
 typedef union {
-	tarval          *tv;
+	ir_tarval      *tv;
 	symconst_symbol sym;
 } lattice_elem_t;
 
@@ -132,7 +161,6 @@ struct node_t {
 	unsigned        on_cprop:1;     /**< Set, if this node is on the partition.cprop list. */
 	unsigned        on_fallen:1;    /**< Set, if this node is on the fallen list. */
 	unsigned        is_follower:1;  /**< Set, if this node is a follower. */
-	unsigned        by_all_const:1; /**< Set, if this node was once evaluated by all constants. */
 	unsigned        flagged:2;      /**< 2 Bits, set if this node was visited by race 1 or 2. */
 };
 
@@ -143,6 +171,7 @@ struct partition_t {
 	list_head         Leader;          /**< The head of partition Leader node list. */
 	list_head         Follower;        /**< The head of partition Follower node list. */
 	list_head         cprop;           /**< The head of partition.cprop list. */
+	list_head         cprop_X;         /**< The head of partition.cprop (Cond nodes and its Projs) list. */
 	partition_t       *wl_next;        /**< Next entry in the work list if any. */
 	partition_t       *touched_next;   /**< Points to the next partition in the touched set. */
 	partition_t       *cprop_next;     /**< Points to the next partition in the cprop list. */
@@ -168,12 +197,14 @@ typedef struct environment_t {
 	partition_t     *touched;       /**< the touched set. */
 	partition_t     *initial;       /**< The initial partition. */
 	set             *opcode2id_map; /**< The opcodeMode->id map. */
-	pmap            *type2id_map;   /**< The type->id map. */
+	ir_node         **kept_memory;  /**< Array of memory nodes that must be kept. */
 	int             end_idx;        /**< -1 for local and 0 for global congruences. */
 	int             lambda_input;   /**< Captured argument for lambda_partition(). */
-	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. */
+	unsigned        modified:1;     /**< Set, if the graph was modified. */
+	unsigned        unopt_cf:1;     /**< If set, control flow is not optimized due to Unknown. */
+	/* options driving the optimization */
+	unsigned        commutative:1;  /**< Set, if commutation nodes should be handled specially. */
+	unsigned        opt_unknown:1;  /**< Set, if non-strict programs should be optimized. */
 #ifdef DEBUG_libfirm
 	partition_t     *dbg_list;      /**< List of all partitions. */
 #endif
@@ -182,8 +213,8 @@ typedef struct environment_t {
 /** Type of the what function. */
 typedef void *(*what_func)(const node_t *node, environment_t *env);
 
-#define get_irn_node(follower)         ((node_t *)get_irn_link(follower))
-#define set_irn_node(follower, node)   set_irn_link(follower, node)
+#define get_irn_node(irn)         ((node_t *)get_irn_link(irn))
+#define set_irn_node(irn, node)   set_irn_link(irn, node)
 
 /* we do NOT use tarval_unreachable here, instead we use Top for this purpose */
 #undef tarval_unreachable
@@ -199,8 +230,8 @@ 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;
+/** The tarval returned by Unknown nodes: set to either tarval_bad OR tarval_top. */
+static ir_tarval *tarval_UNKNOWN;
 
 /* forward */
 static node_t *identity(node_t *node);
@@ -209,7 +240,8 @@ static node_t *identity(node_t *node);
 /**
  * Check a partition.
  */
-static void check_partition(const partition_t *T) {
+static void check_partition(const partition_t *T)
+{
 	node_t   *node;
 	unsigned n = 0;
 
@@ -231,7 +263,8 @@ static void check_partition(const partition_t *T) {
 /**
  * check that all leader nodes in the partition have the same opcode.
  */
-static void check_opcode(const partition_t *Z) {
+static void check_opcode(const partition_t *Z)
+{
 	node_t       *node;
 	opcode_key_t key;
 	int          first = 1;
@@ -253,34 +286,78 @@ static void check_opcode(const partition_t *Z) {
 			case iro_Sel:
 				key.u.ent = get_Sel_entity(irn);
 				break;
+			case iro_Conv:
+				key.u.intVal = get_Conv_strict(irn);
+				break;
+			case iro_Div:
+				key.mode = get_Div_resmode(irn);
+				key.u.intVal = get_Div_no_remainder(irn);
+				break;
+			case iro_Mod:
+				key.mode = get_Mod_resmode(irn);
+				break;
+			case iro_Block:
+				key.u.block = irn;
+				break;
+			case iro_Load:
+				key.mode = get_Load_mode(irn);
+				break;
+			case iro_Builtin:
+				key.u.intVal = get_Builtin_kind(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));
+			assert((unsigned)key.code  == get_irn_opcode(irn));
+			assert(key.arity == get_irn_arity(irn));
 
 			switch (get_irn_opcode(irn)) {
 			case iro_Proj:
+				assert(key.mode  == get_irn_mode(irn));
 				assert(key.u.proj == get_Proj_proj(irn));
 				break;
 			case iro_Sel:
+				assert(key.mode  == get_irn_mode(irn));
 				assert(key.u.ent == get_Sel_entity(irn));
 				break;
+			case iro_Conv:
+				assert(key.mode  == get_irn_mode(irn));
+				assert(key.u.intVal == get_Conv_strict(irn));
+				break;
+			case iro_Div:
+				assert(key.mode  == get_Div_resmode(irn));
+				assert(key.u.intVal == get_Div_no_remainder(irn));
+				break;
+			case iro_Mod:
+				assert(key.mode == get_Mod_resmode(irn));
+				break;
+			case iro_Block:
+				assert(key.mode  == get_irn_mode(irn));
+				assert(key.u.block == irn);
+				break;
+			case iro_Load:
+				assert(key.mode == get_Load_mode(irn));
+				break;
+			case iro_Builtin:
+				assert(key.mode  == get_irn_mode(irn));
+				assert(key.u.intVal == (int) get_Builtin_kind(irn));
+				break;
 			default:
+				assert(key.mode  == get_irn_mode(irn));
 				break;
 			}
 		}
 	}
 }  /* check_opcode */
 
-static void check_all_partitions(environment_t *env) {
+static void check_all_partitions(environment_t *env)
+{
+#ifdef DEBUG_libfirm
 	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)
@@ -291,26 +368,36 @@ static void check_all_partitions(environment_t *env) {
 			assert(leader != node && leader->part == node->part);
 		}
 	}
+#else
+	(void) env;
 #endif
 }
 
 /**
  * Check list.
  */
-static void do_check_list(const node_t *list, int ofs, const partition_t *Z) {
-	const node_t *e;
+static void do_check_list(const node_t *list, int ofs, const partition_t *Z)
+{
 
+#ifndef NDEBUG
+	const node_t *e;
 #define NEXT(e)  *((const node_t **)((char *)(e) + (ofs)))
 	for (e = list; e != NULL; e = NEXT(e)) {
 		assert(e->part == Z);
 	}
 #undef NEXT
+#else
+	(void) list;
+	(void) ofs;
+	(void) Z;
+#endif
 }  /* ido_check_list */
 
 /**
  * Check a local list.
  */
-static void check_list(const node_t *list, const partition_t *Z) {
+static void check_list(const node_t *list, const partition_t *Z)
+{
 	do_check_list(list, offsetof(node_t, next), Z);
 }  /* check_list */
 
@@ -321,12 +408,13 @@ 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.
  */
-static void dump_partition(const char *msg, const partition_t *part) {
+static void dump_partition(const char *msg, const partition_t *part)
+{
 	const node_t   *node;
 	int            first = 1;
 	lattice_elem_t type = get_partition_type(part);
@@ -352,7 +440,8 @@ static void dump_partition(const char *msg, const partition_t *part) {
 /**
  * Dumps a list.
  */
-static void do_dump_list(const char *msg, const node_t *node, int ofs) {
+static void do_dump_list(const char *msg, const node_t *node, int ofs)
+{
 	const node_t *p;
 	int          first = 1;
 
@@ -371,21 +460,24 @@ static void do_dump_list(const char *msg, const node_t *node, int ofs) {
 /**
  * Dumps a race list.
  */
-static void dump_race_list(const char *msg, const node_t *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) {
+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.
  */
-static void dump_all_partitions(const environment_t *env) {
+static void dump_all_partitions(const environment_t *env)
+{
 	const partition_t *P;
 
 	DB((dbg, LEVEL_2, "All partitions\n===============\n"));
@@ -396,7 +488,8 @@ static void dump_all_partitions(const environment_t *env) {
 /**
  * Sump a split list.
  */
-static void dump_split_list(const partition_t *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));
@@ -405,6 +498,18 @@ static void dump_split_list(const partition_t *list) {
 	DB((dbg, LEVEL_2, "\n}\n"));
 }  /* dump_split_list */
 
+/**
+ * Dump partition and type for a node.
+ */
+static int dump_partition_hook(FILE *F, ir_node *n, ir_node *local)
+{
+	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;
+}  /* dump_partition_hook */
+
 #else
 #define dump_partition(msg, part)
 #define dump_race_list(msg, list)
@@ -417,8 +522,9 @@ static void dump_split_list(const partition_t *list) {
 /**
  * Verify that a type transition is monotone
  */
-static void verify_type(const lattice_elem_t old_type, const lattice_elem_t new_type) {
-	if (old_type.tv == new_type.tv) {
+static void verify_type(const lattice_elem_t old_type, node_t *node)
+{
+	if (old_type.tv == node->type.tv) {
 		/* no change */
 		return;
 	}
@@ -426,25 +532,24 @@ static void verify_type(const lattice_elem_t old_type, const lattice_elem_t new_
 		/* from Top down-to is always allowed */
 		return;
 	}
-	if (old_type.tv == tarval_reachable) {
-		panic("verify_type(): wrong translation from %+F to %+F", old_type, new_type);
-	}
-	if (new_type.tv == tarval_bottom || new_type.tv == tarval_reachable) {
+	if (node->type.tv == tarval_bottom || node->type.tv == tarval_reachable) {
 		/* bottom reached */
 		return;
 	}
-	panic("verify_type(): wrong translation from %+F to %+F", old_type, new_type);
+	panic("combo: wrong translation from %+F to %+F on node %+F", old_type, node->type, node->node);
 }  /* verify_type */
+
 #else
-#define verify_type(old_type, new_type)
+#define verify_type(old_type, node)
 #endif
 
 /**
  * Compare two pointer values of a listmap.
  */
-static int listmap_cmp_ptr(const void *elt, const void *key, size_t size) {
-	const listmap_entry_t *e1 = elt;
-	const listmap_entry_t *e2 = key;
+static int listmap_cmp_ptr(const void *elt, const void *key, size_t size)
+{
+	const listmap_entry_t *e1 = (listmap_entry_t*)elt;
+	const listmap_entry_t *e2 = (listmap_entry_t*)key;
 
 	(void) size;
 	return e1->id != e2->id;
@@ -455,7 +560,8 @@ static int listmap_cmp_ptr(const void *elt, const void *key, size_t size) {
  *
  * @param map  the listmap
  */
-static void listmap_init(listmap_t *map) {
+static void listmap_init(listmap_t *map)
+{
 	map->map    = new_set(listmap_cmp_ptr, 16);
 	map->values = NULL;
 }  /* listmap_init */
@@ -465,7 +571,8 @@ static void listmap_init(listmap_t *map) {
  *
  * @param map  the listmap
  */
-static void listmap_term(listmap_t *map) {
+static void listmap_term(listmap_t *map)
+{
 	del_set(map->map);
 }  /* listmap_term */
 
@@ -477,13 +584,14 @@ static void listmap_term(listmap_t *map) {
  *
  * @return the associated listmap entry for the given id
  */
-static listmap_entry_t *listmap_find(listmap_t *map, void *id) {
+static listmap_entry_t *listmap_find(listmap_t *map, void *id)
+{
 	listmap_entry_t key, *entry;
 
 	key.id   = id;
 	key.list = NULL;
 	key.next = NULL;
-	entry = set_insert(map->map, &key, sizeof(key), HASH_PTR(id));
+	entry = (listmap_entry_t*)set_insert(map->map, &key, sizeof(key), HASH_PTR(id));
 
 	if (entry->list == NULL) {
 		/* a new entry, put into the list */
@@ -500,29 +608,34 @@ 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) + entry->arity;
+static unsigned opcode_hash(const opcode_key_t *entry)
+{
+	return (unsigned)(PTR_TO_INT(entry->mode) * 9 + entry->code + entry->u.proj * 3 + HASH_PTR(entry->u.ptr) + entry->arity);
 }  /* opcode_hash */
 
 /**
  * Compare two entries in the opcode map.
  */
-static int cmp_opcode(const void *elt, const void *key, size_t size) {
-	const opcode_key_t *o1 = elt;
-	const opcode_key_t *o2 = key;
+static int cmp_opcode(const void *elt, const void *key, size_t size)
+{
+	const opcode_key_t *o1 = (opcode_key_t*)elt;
+	const opcode_key_t *o2 = (opcode_key_t*)key;
 
 	(void) size;
 	return o1->code != o2->code || o1->mode != o2->mode ||
 	       o1->arity != o2->arity ||
-	       o1->u.proj != o2->u.proj || o1->u.ent != o2->u.ent;
+	       o1->u.proj != o2->u.proj ||
+	       o1->u.intVal != o2->u.intVal || /* this already checks uIntVal */
+	       o1->u.ptr != o2->u.ptr;
 }  /* cmp_opcode */
 
 /**
  * Compare two Def-Use edges for input position.
  */
-static int cmp_def_use_edge(const void *a, const void *b) {
-	const ir_def_use_edge *ea = a;
-	const ir_def_use_edge *eb = b;
+static int cmp_def_use_edge(const void *a, const void *b)
+{
+	const ir_def_use_edge *ea = (const ir_def_use_edge*)a;
+	const ir_def_use_edge *eb = (const ir_def_use_edge*)b;
 
 	/* no overrun, because range is [-1, MAXINT] */
 	return ea->pos - eb->pos;
@@ -531,7 +644,8 @@ static int cmp_def_use_edge(const void *a, const void *b) {
 /**
  * We need the Def-Use edges sorted.
  */
-static void sort_irn_outs(node_t *node) {
+static void sort_irn_outs(node_t *node)
+{
 	ir_node *irn = node->node;
 	int n_outs = get_irn_n_outs(irn);
 
@@ -548,7 +662,8 @@ 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 */
 
@@ -559,7 +674,8 @@ 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 ir_tarval *get_node_tarval(const ir_node *irn)
+{
 	lattice_elem_t type = get_node_type(irn);
 
 	if (is_tarval(type.tv))
@@ -570,7 +686,8 @@ 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;
@@ -585,12 +702,14 @@ 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) {
-	partition_t *part = obstack_alloc(&env->obst, sizeof(*part));
+static inline partition_t *new_partition(environment_t *env)
+{
+	partition_t *part = OALLOC(&env->obst, partition_t);
 
 	INIT_LIST_HEAD(&part->Leader);
 	INIT_LIST_HEAD(&part->Follower);
 	INIT_LIST_HEAD(&part->cprop);
+	INIT_LIST_HEAD(&part->cprop_X);
 	part->wl_next         = NULL;
 	part->touched_next    = NULL;
 	part->cprop_next      = NULL;
@@ -615,7 +734,8 @@ 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 */
 
@@ -627,7 +747,8 @@ 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 */
@@ -642,9 +763,10 @@ static INLINE lattice_elem_t get_partition_type(const partition_t *X) {
  *
  * @return the created node
  */
-static node_t *create_partition_node(ir_node *irn, partition_t *part, environment_t *env) {
+static node_t *create_partition_node(ir_node *irn, partition_t *part, environment_t *env)
+{
 	/* create a partition node and place it in the partition */
-	node_t *node = obstack_alloc(&env->obst, sizeof(*node));
+	node_t *node = OALLOC(&env->obst, node_t);
 
 	INIT_LIST_HEAD(&node->node_list);
 	INIT_LIST_HEAD(&node->cprop_list);
@@ -660,7 +782,6 @@ static node_t *create_partition_node(ir_node *irn, partition_t *part, environmen
 	node->on_cprop       = 0;
 	node->on_fallen      = 0;
 	node->is_follower    = 0;
-	node->by_all_const   = 0;
 	node->flagged        = 0;
 	set_irn_node(irn, node);
 
@@ -671,22 +792,12 @@ static node_t *create_partition_node(ir_node *irn, partition_t *part, environmen
 }  /* create_partition_node */
 
 /**
- * Pre-Walker, init all Block-Phi lists.
- */
-static void init_block_phis(ir_node *irn, void *env) {
-	(void) env;
-
-	if (is_Block(irn)) {
-		set_Block_phis(irn, NULL);
-	}
-}  /* init_block_phis */
-
-/**
- * Post-Walker, initialize all Nodes' type to U or top and place
+ * Pre-Walker, initialize all Nodes' type to U or top and place
  * all nodes into the TOP partition.
  */
-static void create_initial_partitions(ir_node *irn, void *ctx) {
-	environment_t *env  = ctx;
+static void create_initial_partitions(ir_node *irn, void *ctx)
+{
+	environment_t *env  = (environment_t*)ctx;
 	partition_t   *part = env->initial;
 	node_t        *node;
 
@@ -695,14 +806,22 @@ static void create_initial_partitions(ir_node *irn, void *ctx) {
 	if (node->max_user_input > part->max_user_inputs)
 		part->max_user_inputs = node->max_user_input;
 
+	if (is_Block(irn)) {
+		set_Block_phis(irn, NULL);
+	}
+}  /* create_initial_partitions */
+
+/**
+ * Post-Walker, collect  all Block-Phi lists, set Cond.
+ */
+static void init_block_phis(ir_node *irn, void *ctx)
+{
+	(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 */
+}  /* init_block_phis */
 
 /**
  * Add a node to the entry.partition.touched set and
@@ -711,7 +830,8 @@ 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;
 
@@ -736,12 +856,20 @@ static INLINE void add_to_touched(node_t *y, environment_t *env) {
  * @param y    the node
  * @param env  the environment
  */
-static void add_to_cprop(node_t *y, environment_t *env) {
+static void add_to_cprop(node_t *y, environment_t *env)
+{
+	ir_node *irn;
+
 	/* Add y to y.partition.cprop. */
 	if (y->on_cprop == 0) {
 		partition_t *Y = y->part;
+		ir_node *irn   = y->node;
 
-		list_add_tail(&y->cprop_list, &Y->cprop);
+		/* place Conds and all its Projs on the cprop_X list */
+		if (is_Cond(skip_Proj(irn)))
+			list_add_tail(&y->cprop_list, &Y->cprop_X);
+		else
+			list_add_tail(&y->cprop_list, &Y->cprop);
 		y->on_cprop   = 1;
 
 		DB((dbg, LEVEL_3, "Add %+F to part%u.cprop\n", y->node, Y->nr));
@@ -753,22 +881,23 @@ static void add_to_cprop(node_t *y, environment_t *env) {
 			Y->on_cprop   = 1;
 		}
 	}
-	if (get_irn_mode(y->node) == mode_T) {
+	irn = y->node;
+	if (get_irn_mode(irn) == mode_T) {
 		/* mode_T nodes always produce tarval_bottom, so we must explicitly
 		   add it's Proj's to get constant evaluation to work */
 		int i;
 
-		for (i = get_irn_n_outs(y->node) - 1; i >= 0; --i) {
-			node_t *proj = get_irn_node(get_irn_out(y->node, i));
+		for (i = get_irn_n_outs(irn) - 1; i >= 0; --i) {
+			node_t *proj = get_irn_node(get_irn_out(irn, i));
 
 			add_to_cprop(proj, env);
 		}
-	} else if (is_Block(y->node)) {
+	} else if (is_Block(irn)) {
 		/* Due to the way we handle Phi's, we must place all Phis of a block on the list
 		 * if someone placed the block. The Block is only placed if the reachability
 		 * changes, and this must be re-evaluated in compute_Phi(). */
 		ir_node *phi;
-		for (phi = get_Block_phis(y->node); phi != NULL; phi = get_Phi_next(phi)) {
+		for (phi = get_Block_phis(irn); phi != NULL; phi = get_Phi_next(phi)) {
 			node_t *p = get_irn_node(phi);
 			add_to_cprop(p, env);
 		}
@@ -783,7 +912,8 @@ static void add_to_cprop(node_t *y, environment_t *env) {
  * @param Z_prime  the Z' partition, a previous part of Z
  * @param env      the environment
  */
-static void update_worklist(partition_t *Z, partition_t *Z_prime, environment_t *env) {
+static void update_worklist(partition_t *Z, partition_t *Z_prime, environment_t *env)
+{
 	if (Z->on_worklist || Z_prime->n_leader < Z->n_leader) {
 		add_to_worklist(Z_prime, env);
 	} else {
@@ -796,7 +926,8 @@ static void update_worklist(partition_t *Z, partition_t *Z_prime, environment_t
  *
  * @param x  the node
  */
-static void move_edges_to_leader(node_t *x) {
+static void move_edges_to_leader(node_t *x)
+{
 	ir_node     *irn = x->node;
 	int         i, j, k;
 
@@ -841,7 +972,8 @@ static void move_edges_to_leader(node_t *x) {
  *
  * @return  a new partition containing the nodes of g
  */
-static partition_t *split_no_followers(partition_t *Z, node_t *g, environment_t *env) {
+static partition_t *split_no_followers(partition_t *Z, node_t *g, environment_t *env)
+{
 	partition_t *Z_prime;
 	node_t      *node;
 	unsigned    n = 0;
@@ -891,7 +1023,8 @@ static partition_t *split_no_followers(partition_t *Z, node_t *g, environment_t
  *
  * @param n  the node
  */
-static void follower_to_leader(node_t *n) {
+static void follower_to_leader(node_t *n)
+{
 	assert(n->is_follower == 1);
 
 	DB((dbg, LEVEL_2, "%+F make the follower -> leader transition\n", n->node));
@@ -919,7 +1052,8 @@ typedef struct step_env {
  * @param irn    the node to check
  * @param input  number of the input
  */
-static int is_real_follower(const ir_node *irn, int input) {
+static int is_real_follower(const ir_node *irn, int input)
+{
 	node_t *pred;
 
 	switch (get_irn_opcode(irn)) {
@@ -971,10 +1105,6 @@ static int is_real_follower(const ir_node *irn, int input) {
 		if (is_tarval(pred->type.tv) && tarval_is_all_one(pred->type.tv))
 			return 0;
 		break;
-	case iro_Min:
-	case iro_Max:
-		/* all inputs are followers */
-		return 1;
 	default:
 		assert(!"opcode not implemented yet");
 		break;
@@ -985,7 +1115,8 @@ static int is_real_follower(const ir_node *irn, int input) {
 /**
  * Do one step in the race.
  */
-static int step(step_env *env) {
+static int step(step_env *env)
+{
 	node_t *n;
 
 	if (env->initial != NULL) {
@@ -1052,7 +1183,8 @@ static int step(step_env *env) {
  *
  * @param list  the list
  */
-static int clear_flags(node_t *list) {
+static int clear_flags(node_t *list)
+{
 	int    res = 0;
 	node_t *n;
 
@@ -1077,13 +1209,14 @@ static int clear_flags(node_t *list) {
  *
  * @return  a new partition containing the nodes of gg
  */
-static partition_t *split(partition_t **pX, node_t *gg, environment_t *env) {
+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;)
 
@@ -1120,44 +1253,60 @@ 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) {
@@ -1183,7 +1332,7 @@ 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;
 		}
 	}
 
@@ -1197,20 +1346,28 @@ 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 (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;
 	}
@@ -1226,7 +1383,8 @@ static partition_t *split(partition_t **pX, node_t *gg, environment_t *env) {
  *
  * @return non-zero if the i'th input of the given Phi node is live
  */
-static int is_live_input(ir_node *phi, int i) {
+static int is_live_input(ir_node *phi, int i)
+{
 	if (i >= 0) {
 		ir_node        *block = get_nodes_block(phi);
 		ir_node        *pred  = get_Block_cfgpred(block, i);
@@ -1241,7 +1399,8 @@ static int is_live_input(ir_node *phi, int i) {
 /**
  * Return non-zero if a type is a constant.
  */
-static int is_constant_type(lattice_elem_t type) {
+static int is_constant_type(lattice_elem_t type)
+{
 	if (type.tv != tarval_bottom && type.tv != tarval_top)
 		return 1;
 	return 0;
@@ -1253,7 +1412,8 @@ static int is_constant_type(lattice_elem_t type) {
  *
  * @param type  the type to check
  */
-static int type_is_neither_top_nor_const(const lattice_elem_t type) {
+static int type_is_neither_top_nor_const(const lattice_elem_t type)
+{
 	if (is_tarval(type.tv)) {
 		if (type.tv == tarval_top)
 			return 0;
@@ -1273,7 +1433,8 @@ static int type_is_neither_top_nor_const(const lattice_elem_t type) {
  * @param idx   the index of the def_use edge to evaluate
  * @param env   the environment
  */
-static void collect_touched(list_head *list, int idx, environment_t *env) {
+static void collect_touched(list_head *list, int idx, environment_t *env)
+{
 	node_t  *x, *y;
 	int     end_idx = env->end_idx;
 
@@ -1317,7 +1478,7 @@ static void collect_touched(list_head *list, int idx, environment_t *env) {
 				continue;
 
 			if (is_constant_type(y->type)) {
-				ir_opcode code = get_irn_opcode(succ);
+				unsigned  code = get_irn_opcode(succ);
 				if (code == iro_Sub || code == iro_Cmp)
 					add_to_cprop(y, env);
 			}
@@ -1338,7 +1499,8 @@ static void collect_touched(list_head *list, int idx, environment_t *env) {
  * @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) {
+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) {
@@ -1369,7 +1531,7 @@ static void collect_commutative_touched(list_head *list, environment_t *env) {
 
 			y = get_irn_node(succ);
 			if (is_constant_type(y->type)) {
-				ir_opcode code = get_irn_opcode(succ);
+				unsigned code = get_irn_opcode(succ);
 				if (code == iro_Eor)
 					add_to_cprop(y, env);
 			}
@@ -1388,7 +1550,8 @@ static void collect_commutative_touched(list_head *list, environment_t *env) {
  *
  * @param env  the environment
  */
-static void cause_splits(environment_t *env) {
+static void cause_splits(environment_t *env)
+{
 	partition_t *X, *Z, *N;
 	int         idx;
 
@@ -1409,9 +1572,12 @@ static void cause_splits(environment_t *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;
+			node_t   *e, *n;
+			node_t   *touched     = Z->touched;
+			node_t   *touched_aa  = NULL;
+			node_t   *touched_ab  = NULL;
+			unsigned n_touched_aa = 0;
+			unsigned n_touched_ab = 0;
 
 			assert(Z->touched != NULL);
 
@@ -1422,18 +1588,45 @@ static void cause_splits(environment_t *env) {
 			Z->on_touched = 0;
 
 			/* Empty local Z.touched. */
-			for (e = touched; e != NULL; e = e->next) {
+			for (e = touched; e != NULL; e = n) {
+				node_t *left  = get_irn_node(get_irn_n(e->node, 0));
+				node_t *right = get_irn_node(get_irn_n(e->node, 1));
+
 				assert(e->is_follower == 0);
 				e->on_touched = 0;
+				n = e->next;
+
+				/*
+				 * Note: op(a, a) is NOT congruent to op(a, b).
+				 * So, we must split the touched list.
+				 */
+				if (left->part == right->part) {
+					e->next = touched_aa;
+					touched_aa = e;
+					++n_touched_aa;
+				} else {
+					e->next = touched_ab;
+					touched_ab = e;
+					++n_touched_ab;
+				}
 			}
+			assert(n_touched_aa + n_touched_ab == Z->n_touched);
 			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);
+			if (0 < n_touched_aa && n_touched_aa < Z->n_leader) {
+				partition_t *Z_prime = Z;
+				DB((dbg, LEVEL_2, "Split part%d by touched_aa\n", Z_prime->nr));
+				split(&Z_prime, touched_aa, env);
 			} else
-				assert(n_touched <= Z->n_leader);
+				assert(n_touched_aa <= Z->n_leader);
+
+			if (0 < n_touched_ab && n_touched_ab < Z->n_leader) {
+				partition_t *Z_prime = Z;
+				DB((dbg, LEVEL_2, "Split part%d by touched_ab\n", Z_prime->nr));
+				split(&Z_prime, touched_ab, env);
+			} else
+				assert(n_touched_ab <= Z->n_leader);
 		}
 	}
 
@@ -1487,7 +1680,8 @@ static void cause_splits(environment_t *env) {
  * @return *P
  */
 static partition_t *split_by_what(partition_t *X, what_func What,
-                                  partition_t **P, environment_t *env) {
+                                  partition_t **P, environment_t *env)
+{
 	node_t          *x, *S;
 	listmap_t       map;
 	listmap_entry_t *iter;
@@ -1533,13 +1727,15 @@ static partition_t *split_by_what(partition_t *X, what_func What,
 }  /* split_by_what */
 
 /** lambda n.(n.type) */
-static void *lambda_type(const node_t *node, environment_t *env) {
+static void *lambda_type(const node_t *node, environment_t *env)
+{
 	(void)env;
 	return node->type.tv;
 }  /* lambda_type */
 
 /** lambda n.(n.opcode) */
-static void *lambda_opcode(const node_t *node, environment_t *env) {
+static void *lambda_opcode(const node_t *node, environment_t *env)
+{
 	opcode_key_t key, *entry;
 	ir_node      *irn = node->node;
 
@@ -1556,16 +1752,38 @@ static void *lambda_opcode(const node_t *node, environment_t *env) {
 	case iro_Sel:
 		key.u.ent = get_Sel_entity(irn);
 		break;
+	case iro_Conv:
+		key.u.intVal = get_Conv_strict(irn);
+		break;
+	case iro_Div:
+		key.u.intVal = get_Div_no_remainder(irn);
+		break;
+	case iro_Block:
+		/*
+		 * Some ugliness here: Two Blocks having the same
+		 * IJmp predecessor would be congruent, which of course is wrong.
+		 * We fix it by never letting blocks be congruent
+		 * which cannot be detected by combo either.
+		 */
+		key.u.block = irn;
+		break;
+	case iro_Load:
+		key.mode = get_Load_mode(irn);
+		break;
+	case iro_Builtin:
+		key.u.intVal = get_Builtin_kind(irn);
+		break;
 	default:
 		break;
 	}
 
-	entry = set_insert(env->opcode2id_map, &key, sizeof(key), opcode_hash(&key));
+	entry = (opcode_key_t*)set_insert(env->opcode2id_map, &key, sizeof(key), opcode_hash(&key));
 	return entry;
 }  /* lambda_opcode */
 
 /** lambda n.(n[i].partition) */
-static void *lambda_partition(const node_t *node, environment_t *env) {
+static void *lambda_partition(const node_t *node, environment_t *env)
+{
 	ir_node *skipped = skip_Proj(node->node);
 	ir_node *pred;
 	node_t  *p;
@@ -1589,12 +1807,12 @@ static void *lambda_partition(const node_t *node, environment_t *env) {
 
 	pred = i == -1 ? get_irn_n(skipped, i) : get_irn_n(node->node, i);
 	p    = get_irn_node(pred);
-
 	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) {
+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;
@@ -1646,9 +1864,11 @@ static void *lambda_commutative_partition(const node_t *node, environment_t *env
 }  /* lambda_commutative_partition */
 
 /**
- * Returns true if a type is a constant.
+ * Returns true if a type is a constant (and NOT Top
+ * or Bottom).
  */
-static int is_con(const lattice_elem_t type) {
+static int is_con(const lattice_elem_t type)
+{
 	/* be conservative */
 	if (is_tarval(type.tv))
 		return tarval_is_constant(type.tv);
@@ -1661,7 +1881,8 @@ static int is_con(const lattice_elem_t type) {
  * @param X    the partition to split
  * @param env  the environment
  */
-static void split_by(partition_t *X, environment_t *env) {
+static void split_by(partition_t *X, environment_t *env)
+{
 	partition_t *I, *P = NULL;
 	int         input;
 
@@ -1750,15 +1971,10 @@ static void split_by(partition_t *X, environment_t *env) {
  *
  * @param node  the node
  */
-static void default_compute(node_t *node) {
+static void default_compute(node_t *node)
+{
 	int     i;
 	ir_node *irn = node->node;
-	node_t  *block = get_irn_node(get_nodes_block(irn));
-
-	if (block->type.tv == tarval_unreachable) {
-		node->type.tv = tarval_top;
-		return;
-	}
 
 	/* if any of the data inputs have type top, the result is type top */
 	for (i = get_irn_arity(irn) - 1; i >= 0; --i) {
@@ -1782,12 +1998,13 @@ static void default_compute(node_t *node) {
  *
  * @param node  the node
  */
-static void compute_Block(node_t *node) {
+static void compute_Block(node_t *node)
+{
 	int     i;
 	ir_node *block = node->node;
 
-	if (block == get_irg_start_block(current_ir_graph)) {
-		/* start block is always reachable */
+	if (block == get_irg_start_block(current_ir_graph) || has_Block_entity(block)) {
+		/* start block and labelled blocks are always reachable */
 		node->type.tv = tarval_reachable;
 		return;
 	}
@@ -1809,7 +2026,8 @@ static void compute_Block(node_t *node) {
  *
  * @param node  the node
  */
-static void compute_Bad(node_t *node) {
+static void compute_Bad(node_t *node)
+{
 	/* Bad nodes ALWAYS compute Top */
 	node->type.tv = tarval_top;
 }  /* compute_Bad */
@@ -1819,7 +2037,8 @@ static void compute_Bad(node_t *node) {
  *
  * @param node  the node
  */
-static void compute_Unknown(node_t *node) {
+static void compute_Unknown(node_t *node)
+{
 	/* While Unknown nodes should compute Top this is dangerous:
 	 * a Top input to a Cond would lead to BOTH control flows unreachable.
 	 * While this is correct in the given semantics, it would destroy the Firm
@@ -1828,7 +2047,7 @@ static void compute_Unknown(node_t *node) {
 	 * It would be safe to compute Top IF it can be assured, that only Cmp
 	 * 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...
+	 * (jump threading for instance) might replace them by Phib's...
 	 */
 	node->type.tv = tarval_UNKNOWN;
 }  /* compute_Unknown */
@@ -1838,28 +2057,58 @@ static void compute_Unknown(node_t *node) {
  *
  * @param node  the node
  */
-static void compute_Jmp(node_t *node) {
+static void compute_Jmp(node_t *node)
+{
 	node_t *block = get_irn_node(get_nodes_block(node->node));
 
 	node->type = block->type;
 }  /* compute_Jmp */
 
+/**
+ * (Re-)compute the type for the Return node.
+ *
+ * @param node  the node
+ */
+static void compute_Return(node_t *node)
+{
+	/* The Return node is NOT dead if it is in a reachable block.
+	 * This is already checked in compute(). so we can return
+	 * Reachable here. */
+	node->type.tv = tarval_reachable;
+}  /* compute_Return */
+
 /**
  * (Re-)compute the type for the End node.
  *
  * @param node  the node
  */
-static void compute_End(node_t *node) {
+static void compute_End(node_t *node)
+{
 	/* the End node is NOT dead of course */
 	node->type.tv = tarval_reachable;
-}
+}  /* compute_End */
+
+/**
+ * (Re-)compute the type for a Call.
+ *
+ * @param node  the node
+ */
+static void compute_Call(node_t *node)
+{
+	/*
+	 * A Call computes always bottom, even if it has Unknown
+	 * predecessors.
+	 */
+	node->type.tv = tarval_bottom;
+}  /* compute_Call */
 
 /**
  * (Re-)compute the type for a SymConst node.
  *
  * @param node  the node
  */
-static void compute_SymConst(node_t *node) {
+static void compute_SymConst(node_t *node)
+{
 	ir_node *irn = node->node;
 	node_t  *block = get_irn_node(get_nodes_block(irn));
 
@@ -1869,7 +2118,6 @@ static void compute_SymConst(node_t *node) {
 	}
 	switch (get_SymConst_kind(irn)) {
 	case symconst_addr_ent:
-	/* case symconst_addr_name: cannot handle this yet */
 		node->type.sym = get_SymConst_symbol(irn);
 		break;
 	default:
@@ -1882,7 +2130,8 @@ static void compute_SymConst(node_t *node) {
  *
  * @param node  the node
  */
-static void compute_Phi(node_t *node) {
+static void compute_Phi(node_t *node)
+{
 	int            i;
 	ir_node        *phi = node->node;
 	lattice_elem_t type;
@@ -1929,7 +2178,8 @@ static void compute_Phi(node_t *node) {
  *
  * @param node  the node
  */
-static void compute_Add(node_t *node) {
+static void compute_Add(node_t *node)
+{
 	ir_node        *sub = node->node;
 	node_t         *l   = get_irn_node(get_Add_left(sub));
 	node_t         *r   = get_irn_node(get_Add_right(sub));
@@ -1970,13 +2220,14 @@ static void compute_Add(node_t *node) {
  *
  * @param node  the node
  */
-static void compute_Sub(node_t *node) {
+static void compute_Sub(node_t *node)
+{
 	ir_node        *sub = node->node;
 	node_t         *l   = get_irn_node(get_Sub_left(sub));
 	node_t         *r   = get_irn_node(get_Sub_right(sub));
 	lattice_elem_t a    = l->type;
 	lattice_elem_t b    = r->type;
-	tarval         *tv;
+	ir_tarval      *tv;
 
 	if (a.tv == tarval_top || b.tv == tarval_top) {
 		node->type.tv = tarval_top;
@@ -1990,7 +2241,6 @@ static void compute_Sub(node_t *node) {
 		} else {
 			node->type.tv = tarval_bottom;
 		}
-		node->by_all_const = 1;
 	} else if (r->part == l->part &&
 	           (!mode_is_float(get_irn_mode(l->node)))) {
 		/*
@@ -2004,7 +2254,7 @@ static void compute_Sub(node_t *node) {
 		   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)
+		if (node->type.tv != tv)
 			tv = tarval_bottom;
 		node->type.tv = tv;
 	} else {
@@ -2017,13 +2267,14 @@ static void compute_Sub(node_t *node) {
  *
  * @param node  the node
  */
-static void compute_Eor(node_t *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;
+	ir_tarval      *tv;
 
 	if (a.tv == tarval_top || b.tv == tarval_top) {
 		node->type.tv = tarval_top;
@@ -2037,7 +2288,6 @@ static void compute_Eor(node_t *node) {
 		} 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);
@@ -2046,7 +2296,7 @@ static void compute_Eor(node_t *node) {
 		   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)
+		if (node->type.tv != tv)
 			tv = tarval_bottom;
 		node->type.tv = tv;
 	} else {
@@ -2059,33 +2309,31 @@ static void compute_Eor(node_t *node) {
  *
  * @param node  the node
  */
-static void compute_Cmp(node_t *node) {
+static void compute_Cmp(node_t *node)
+{
 	ir_node        *cmp  = node->node;
 	node_t         *l    = get_irn_node(get_Cmp_left(cmp));
 	node_t         *r    = get_irn_node(get_Cmp_right(cmp));
 	lattice_elem_t a     = l->type;
 	lattice_elem_t b     = r->type;
+	ir_mode        *mode = get_irn_mode(get_Cmp_left(cmp));
 
 	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;
 	} else if (r->part == l->part) {
 		/* both nodes congruent, we can probably do something */
+		if (mode_is_float(mode)) {
+			/* beware of NaN's */
+			node->type.tv = tarval_bottom;
+		} else {
+			node->type.tv = tarval_b_true;
+		}
+	} else if (is_con(a) && is_con(b)) {
 		node->type.tv = tarval_b_true;
 	} else {
 		node->type.tv = tarval_bottom;
 	}
-}  /* compute_Proj_Cmp */
+}  /* compute_Cmp */
 
 /**
  * (Re-)compute the type for a Proj(Cmp).
@@ -2093,42 +2341,35 @@ static void compute_Cmp(node_t *node) {
  * @param node  the node
  * @param cond  the predecessor Cmp node
  */
-static void compute_Proj_Cmp(node_t *node, ir_node *cmp) {
+static void compute_Proj_Cmp(node_t *node, ir_node *cmp)
+{
 	ir_node        *proj = node->node;
 	node_t         *l    = get_irn_node(get_Cmp_left(cmp));
 	node_t         *r    = get_irn_node(get_Cmp_right(cmp));
 	lattice_elem_t a     = l->type;
 	lattice_elem_t b     = r->type;
-	pn_Cmp         pnc   = get_Proj_proj(proj);
-	tarval         *tv;
+	pn_Cmp         pnc   = get_Proj_pn_cmp(proj);
+	ir_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
+		node->type.tv = tarval_undefined;
 	} else if (is_con(a) && is_con(b)) {
 		default_compute(node);
-		node->by_all_const = 1;
-	} else if (r->part == l->part &&
-	           (!mode_is_float(get_irn_mode(l->node)) || pnc == pn_Cmp_Lt || pnc == pn_Cmp_Gt)) {
-		/*
-		 * BEWARE: a == a is NOT always True for floating Point values, as
-		 * 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
+
+	/*
+	 * BEWARE: a == a is NOT always True for floating Point values, as
+	 * NaN != NaN is defined, so we must check this here.
+	 * (while for some pnc we could still optimize we have to stay
+	 *  consistent with compute_Cmp, so don't do anything for floats)
+	 */
+	} else if (r->part == l->part && !mode_is_float(get_irn_mode(l->node))) {
+		tv = pnc & pn_Cmp_Eq ? tarval_b_true : tarval_b_false;
 
 		/* 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)
+		if (node->type.tv != tv)
 			tv = tarval_bottom;
 		node->type.tv = tv;
 	} else {
@@ -2142,12 +2383,65 @@ not_equal:
  * @param node  the node
  * @param cond  the predecessor Cond node
  */
-static void compute_Proj_Cond(node_t *node, ir_node *cond) {
+static void compute_Proj_Cond(node_t *node, ir_node *cond)
+{
 	ir_node *proj     = node->node;
 	long    pnc       = get_Proj_proj(proj);
 	ir_node *sel      = get_Cond_selector(cond);
 	node_t  *selector = get_irn_node(sel);
 
+	/*
+	 * Note: it is crucial for the monotony that the Proj(Cond)
+	 * are evaluates after all predecessors of the Cond selector are
+	 * processed.
+	 * Example
+	 *
+	 * if (x != 0)
+	 *
+	 * Due to the fact that 0 is a const, the Cmp gets immediately
+	 * on the cprop list. It will be evaluated before x is evaluated,
+	 * might leaving x as Top. When later x is evaluated, the Cmp
+	 * might change its value.
+	 * BUT if the Cond is evaluated before this happens, Proj(Cond, FALSE)
+	 * gets R, and later changed to F if Cmp is evaluated to True!
+	 *
+	 * We prevent this by putting Conds in an extra cprop_X queue, which
+	 * gets evaluated after the cprop queue is empty.
+	 *
+	 * Note that this even happens with Click's original algorithm, if
+	 * Cmp(x, 0) is evaluated to True first and later changed to False
+	 * if x was Top first and later changed to a Const ...
+	 * It is unclear how Click solved that problem ...
+	 *
+	 * However, in rare cases even this does not help, if a Top reaches
+	 * a compare  through a Phi, than Proj(Cond) is evaluated changing
+	 * the type of the Phi to something other.
+	 * So, we take the last resort and bind the type to R once
+	 * it is calculated.
+	 *
+	 * (This might be even the way Click works around the whole problem).
+	 *
+	 * Finally, we may miss some optimization possibilities due to this:
+	 *
+	 * x = phi(Top, y)
+	 * if (x == 0)
+	 *
+	 * If Top reaches the if first, than we decide for != here.
+	 * If y later is evaluated to 0, we cannot revert this decision
+	 * and must live with both outputs enabled. If this happens,
+	 * we get an unresolved if (true) in the code ...
+	 *
+	 * In Click's version where this decision is done at the Cmp,
+	 * the Cmp is NOT optimized away than (if y evaluated to 1
+	 * for instance) and we get a if (1 == 0) here ...
+	 *
+	 * Both solutions are suboptimal.
+	 * At least, we could easily detect this problem and run
+	 * cf_opt() (or even combo) again :-(
+	 */
+	if (node->type.tv == tarval_reachable)
+		return;
+
 	if (get_irn_mode(sel) == mode_b) {
 		/* an IF */
 		if (pnc == pn_Cond_true) {
@@ -2159,7 +2453,12 @@ static void compute_Proj_Cond(node_t *node, ir_node *cond) {
 				node->type.tv = tarval_reachable;
 			} else {
 				assert(selector->type.tv == tarval_top);
-				node->type.tv = tarval_unreachable;
+				if (tarval_UNKNOWN == tarval_top) {
+					/* any condition based on Top is "!=" */
+					node->type.tv = tarval_unreachable;
+				} else {
+					node->type.tv = tarval_unreachable;
+				}
 			}
 		} else {
 			assert(pnc == pn_Cond_false);
@@ -2172,7 +2471,12 @@ static void compute_Proj_Cond(node_t *node, ir_node *cond) {
 				node->type.tv = tarval_reachable;
 			} else {
 				assert(selector->type.tv == tarval_top);
-				node->type.tv = tarval_unreachable;
+				if (tarval_UNKNOWN == tarval_top) {
+					/* any condition based on Top is "!=" */
+					node->type.tv = tarval_reachable;
+				} else {
+					node->type.tv = tarval_unreachable;
+				}
 			}
 		}
 	} else {
@@ -2180,10 +2484,16 @@ static void compute_Proj_Cond(node_t *node, ir_node *cond) {
 		if (selector->type.tv == tarval_bottom) {
 			node->type.tv = tarval_reachable;
 		} else if (selector->type.tv == tarval_top) {
-			node->type.tv = tarval_unreachable;
+			if (tarval_UNKNOWN == tarval_top &&
+			    pnc == get_Cond_default_proj(cond)) {
+				/* a switch based of Top is always "default" */
+				node->type.tv = tarval_reachable;
+			} else {
+				node->type.tv = tarval_unreachable;
+			}
 		} else {
 			long value = get_tarval_long(selector->type.tv);
-			if (pnc == get_Cond_defaultProj(cond)) {
+			if (pnc == get_Cond_default_proj(cond)) {
 				/* default switch, have to check ALL other cases */
 				int i;
 
@@ -2213,7 +2523,8 @@ static void compute_Proj_Cond(node_t *node, ir_node *cond) {
  *
  * @param node  the node
  */
-static void compute_Proj(node_t *node) {
+static void compute_Proj(node_t *node)
+{
 	ir_node *proj = node->node;
 	ir_mode *mode = get_irn_mode(proj);
 	node_t  *block = get_irn_node(get_nodes_block(skip_Proj(proj)));
@@ -2224,7 +2535,7 @@ static void compute_Proj(node_t *node) {
 		node->type.tv = tarval_top;
 		return;
 	}
-	if (get_irn_node(pred)->type.tv == tarval_top) {
+	if (get_irn_node(pred)->type.tv == tarval_top && !is_Cond(pred)) {
 		/* if the predecessor is Top, its Proj follow */
 		node->type.tv = tarval_top;
 		return;
@@ -2263,7 +2574,8 @@ static void compute_Proj(node_t *node) {
  *
  * @param node  the node
  */
-static void compute_Confirm(node_t *node) {
+static void compute_Confirm(node_t *node)
+{
 	ir_node *confirm = node->node;
 	node_t  *pred = get_irn_node(get_Confirm_value(confirm));
 
@@ -2280,108 +2592,36 @@ static void compute_Confirm(node_t *node) {
 	node->type = pred->type;
 }  /* compute_Confirm */
 
-/**
- * (Re-)compute the type for a Max.
- *
- * @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;
-
-	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 */
-			node->type = a;
-		} else {
-			ir_mode *mode   = get_irn_mode(op);
-			tarval  *tv_min = get_mode_min(mode);
-
-			if (a.tv == tv_min)
-				node->type = b;
-			else if (b.tv == tv_min)
-				node->type = a;
-			else if (is_tarval(a.tv) && is_tarval(b.tv)) {
-				if (tarval_cmp(a.tv, b.tv) & pn_Cmp_Gt)
-					node->type.tv = a.tv;
-				else
-					node->type.tv = b.tv;
-			} else {
-				node->type.tv = tarval_bad;
-			}
-		}
-	} else if (r->part == l->part) {
-		/* both nodes congruent, we can probably do something */
-		node->type = a;
-	} else {
-		node->type.tv = tarval_bottom;
-	}
-}  /* compute_Max */
-
-/**
- * (Re-)compute the type for a Min.
- *
- * @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;
-
-	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 */
-			node->type = a;
-		} else {
-			ir_mode *mode   = get_irn_mode(op);
-			tarval  *tv_max = get_mode_max(mode);
-
-			if (a.tv == tv_max)
-				node->type = b;
-			else if (b.tv == tv_max)
-				node->type = a;
-			else if (is_tarval(a.tv) && is_tarval(b.tv)) {
-				if (tarval_cmp(a.tv, b.tv) & pn_Cmp_Gt)
-					node->type.tv = a.tv;
-				else
-					node->type.tv = b.tv;
-			} else {
-				node->type.tv = tarval_bad;
-			}
-		}
-	} else if (r->part == l->part) {
-		/* both nodes congruent, we can probably do something */
-		node->type = a;
-	} else {
-		node->type.tv = tarval_bottom;
-	}
-}  /* compute_Min */
-
 /**
  * (Re-)compute the type for a given node.
  *
  * @param node  the node
  */
-static void compute(node_t *node) {
+static void compute(node_t *node)
+{
+	ir_node *irn = node->node;
 	compute_func func;
 
-	if (is_no_Block(node->node)) {
-		node_t *block = get_irn_node(get_nodes_block(node->node));
+#ifndef VERIFY_MONOTONE
+	/*
+	 * Once a node reaches bottom, the type cannot fall further
+	 * in the lattice and we can stop computation.
+	 * Do not take this exit if the monotony verifier is
+	 * enabled to catch errors.
+	 */
+	if (node->type.tv == tarval_bottom)
+		return;
+#endif
 
-		if (block->type.tv == tarval_unreachable) {
-			node->type.tv = tarval_top;
-			return;
+	if (!is_Block(irn)) {
+		/* for pinned nodes, check its control input */
+		if (get_irn_pinned(skip_Proj(irn)) == op_pin_state_pinned) {
+			node_t *block = get_irn_node(get_nodes_block(irn));
+
+			if (block->type.tv == tarval_unreachable) {
+				node->type.tv = tarval_top;
+				return;
+			}
 		}
 	}
 
@@ -2391,7 +2631,7 @@ static void compute(node_t *node) {
 }  /* compute */
 
 /*
- * Identity functions: Note that one might thing that identity() is just a
+ * Identity functions: Note that one might think that identity() is just a
  * synonym for equivalent_node(). While this is true, we cannot use it for the algorithm
  * here, because it expects that the identity node is one of the inputs, which is NOT
  * always true for equivalent_node() which can handle (and does sometimes) DAGs.
@@ -2401,7 +2641,8 @@ static void compute(node_t *node) {
 /**
  * Calculates the Identity for Phi nodes
  */
-static node_t *identity_Phi(node_t *node) {
+static node_t *identity_Phi(node_t *node)
+{
 	ir_node *phi    = node->node;
 	ir_node *block  = get_nodes_block(phi);
 	node_t  *n_part = NULL;
@@ -2430,12 +2671,13 @@ static node_t *identity_Phi(node_t *node) {
 /**
  * Calculates the Identity for commutative 0 neutral nodes.
  */
-static node_t *identity_comm_zero_binop(node_t *node) {
-	ir_node *op   = node->node;
-	node_t  *a    = get_irn_node(get_binop_left(op));
-	node_t  *b    = get_irn_node(get_binop_right(op));
-	ir_mode *mode = get_irn_mode(op);
-	tarval  *zero;
+static node_t *identity_comm_zero_binop(node_t *node)
+{
+	ir_node   *op   = node->node;
+	node_t    *a    = get_irn_node(get_binop_left(op));
+	node_t    *b    = get_irn_node(get_binop_right(op));
+	ir_mode   *mode = get_irn_mode(op);
+	ir_tarval *zero;
 
 	/* for FP these optimizations are only allowed if fp_strict_algebraic is disabled */
 	if (mode_is_float(mode) && (get_irg_fp_model(current_ir_graph) & fp_strict_algebraic))
@@ -2454,11 +2696,12 @@ static node_t *identity_comm_zero_binop(node_t *node) {
 /**
  * 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;
+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);
+	ir_tarval *zero;
 
 	/* node: no input should be tarval_top, else the binop would be also
 	 * Top and not being split. */
@@ -2471,12 +2714,13 @@ static node_t *identity_shift(node_t *node) {
 /**
  * Calculates the Identity for Mul nodes.
  */
-static node_t *identity_Mul(node_t *node) {
-	ir_node *op   = node->node;
-	node_t  *a    = get_irn_node(get_Mul_left(op));
-	node_t  *b    = get_irn_node(get_Mul_right(op));
-	ir_mode *mode = get_irn_mode(op);
-	tarval  *one;
+static node_t *identity_Mul(node_t *node)
+{
+	ir_node   *op   = node->node;
+	node_t    *a    = get_irn_node(get_Mul_left(op));
+	node_t    *b    = get_irn_node(get_Mul_right(op));
+	ir_mode   *mode = get_irn_mode(op);
+	ir_tarval *one;
 
 	/* for FP these optimizations are only allowed if fp_strict_algebraic is disabled */
 	if (mode_is_float(mode) && (get_irg_fp_model(current_ir_graph) & fp_strict_algebraic))
@@ -2495,7 +2739,8 @@ static node_t *identity_Mul(node_t *node) {
 /**
  * Calculates the Identity for Sub nodes.
  */
-static node_t *identity_Sub(node_t *node) {
+static node_t *identity_Sub(node_t *node)
+{
 	ir_node *sub  = node->node;
 	node_t  *b    = get_irn_node(get_Sub_right(sub));
 	ir_mode *mode = get_irn_mode(sub);
@@ -2514,11 +2759,12 @@ static node_t *identity_Sub(node_t *node) {
 /**
  * Calculates the Identity for And nodes.
  */
-static node_t *identity_And(node_t *node) {
-	ir_node *and = node->node;
-	node_t  *a   = get_irn_node(get_And_left(and));
-	node_t  *b   = get_irn_node(get_And_right(and));
-	tarval  *neutral = get_mode_all_one(get_irn_mode(and));
+static node_t *identity_And(node_t *node)
+{
+	ir_node   *andnode = node->node;
+	node_t    *a       = get_irn_node(get_And_left(andnode));
+	node_t    *b       = get_irn_node(get_And_right(andnode));
+	ir_tarval *neutral = get_mode_all_one(get_irn_mode(andnode));
 
 	/* node: no input should be tarval_top, else the And would be also
 	 * Top and not being split. */
@@ -2532,7 +2778,8 @@ static node_t *identity_And(node_t *node) {
 /**
  * Calculates the Identity for Confirm nodes.
  */
-static node_t *identity_Confirm(node_t *node) {
+static node_t *identity_Confirm(node_t *node)
+{
 	ir_node *confirm = node->node;
 
 	/* a Confirm is always a Copy */
@@ -2542,7 +2789,8 @@ static node_t *identity_Confirm(node_t *node) {
 /**
  * Calculates the Identity for Mux nodes.
  */
-static node_t *identity_Mux(node_t *node) {
+static node_t *identity_Mux(node_t *node)
+{
 	ir_node *mux = node->node;
 	node_t  *t   = get_irn_node(get_Mux_true(mux));
 	node_t  *f   = get_irn_node(get_Mux_false(mux));
@@ -2564,58 +2812,11 @@ static node_t *identity_Mux(node_t *node) {
 	return node;
 }  /* identity_Mux */
 
-/**
- * Calculates the Identity for Min nodes.
- */
-static node_t *identity_Min(node_t *node) {
-	ir_node *op   = node->node;
-	node_t  *a    = get_irn_node(get_binop_left(op));
-	node_t  *b    = get_irn_node(get_binop_right(op));
-	ir_mode *mode = get_irn_mode(op);
-	tarval  *tv_max;
-
-	if (a->part == b->part) {
-		/* leader of multiple predecessors */
-		return a;
-	}
-
-	/* works even with NaN */
-	tv_max = get_mode_max(mode);
-	if (a->type.tv == tv_max)
-		return b;
-	if (b->type.tv == tv_max)
-		return a;
-	return node;
-}  /* identity_Min */
-
-/**
- * Calculates the Identity for Max nodes.
- */
-static node_t *identity_Max(node_t *node) {
-	ir_node *op   = node->node;
-	node_t  *a    = get_irn_node(get_binop_left(op));
-	node_t  *b    = get_irn_node(get_binop_right(op));
-	ir_mode *mode = get_irn_mode(op);
-	tarval  *tv_min;
-
-	if (a->part == b->part) {
-		/* leader of multiple predecessors */
-		return a;
-	}
-
-	/* works even with NaN */
-	tv_min = get_mode_min(mode);
-	if (a->type.tv == tv_min)
-		return b;
-	if (b->type.tv == tv_min)
-		return a;
-	return node;
-}  /* identity_Max */
-
 /**
  * Calculates the Identity for nodes.
  */
-static node_t *identity(node_t *node) {
+static node_t *identity(node_t *node)
+{
 	ir_node *irn = node->node;
 
 	switch (get_irn_opcode(irn)) {
@@ -2640,10 +2841,6 @@ static node_t *identity(node_t *node) {
 		return identity_Confirm(node);
 	case iro_Mux:
 		return identity_Mux(node);
-	case iro_Min:
-		return identity_Min(node);
-	case iro_Max:
-		return identity_Max(node);
 	default:
 		return node;
 	}
@@ -2653,7 +2850,8 @@ static node_t *identity(node_t *node) {
  * Node follower is a (new) follower of leader, segregate Leader
  * out edges.
  */
-static void segregate_def_use_chain_1(const ir_node *follower, node_t *leader) {
+static void segregate_def_use_chain_1(const ir_node *follower, node_t *leader)
+{
 	ir_node *l   = leader->node;
 	int     j, i, n = get_irn_n_outs(l);
 
@@ -2679,7 +2877,8 @@ static void segregate_def_use_chain_1(const ir_node *follower, node_t *leader) {
  *
  * @param follower  the follower IR node
  */
-static void segregate_def_use_chain(const ir_node *follower) {
+static void segregate_def_use_chain(const ir_node *follower)
+{
 	int i;
 
 	for (i = get_irn_arity(follower) - 1; i >= 0; --i) {
@@ -2694,7 +2893,8 @@ static void segregate_def_use_chain(const ir_node *follower) {
  *
  * @param env  the environment
  */
-static void propagate(environment_t *env) {
+static void propagate(environment_t *env)
+{
 	partition_t    *X, *Y;
 	node_t         *x;
 	lattice_elem_t old_type;
@@ -2715,9 +2915,27 @@ static void propagate(environment_t *env) {
 		DB((dbg, LEVEL_2, "Propagate type on part%d\n", X->nr));
 		fallen   = NULL;
 		n_fallen = 0;
-		while (! list_empty(&X->cprop)) {
+		for (;;) {
+			int cprop_empty   = list_empty(&X->cprop);
+			int cprop_X_empty = list_empty(&X->cprop_X);
+
+			if (cprop_empty && cprop_X_empty) {
+				/* both cprop lists are empty */
+				break;
+			}
+
 			/* remove the first Node x from X.cprop */
-			x = list_entry(X->cprop.next, node_t, cprop_list);
+			if (cprop_empty) {
+				/* Get a node from the cprop_X list only if
+				 * all data nodes are processed.
+				 * This ensures, that all inputs of the Cond
+				 * predecessor are processed if its type is still Top.
+				 */
+				x = list_entry(X->cprop_X.next, node_t, cprop_list);
+			} else {
+				x = list_entry(X->cprop.next, node_t, cprop_list);
+			}
+
 			//assert(x->part == X);
 			list_del(&x->cprop_list);
 			x->on_cprop = 0;
@@ -2747,8 +2965,8 @@ static void propagate(environment_t *env) {
 			DB((dbg, LEVEL_3, "computing type of %+F\n", x->node));
 			compute(x);
 			if (x->type.tv != old_type.tv) {
-				verify_type(old_type, x->type);
 				DB((dbg, LEVEL_2, "node %+F has changed type from %+F to %+F\n", x->node, old_type, x->type));
+				verify_type(old_type, x);
 
 				if (x->on_fallen == 0) {
 					/* Add x to fallen. Nodes might fall from T -> const -> _|_, so check that they are
@@ -2814,7 +3032,8 @@ static void propagate(environment_t *env) {
  *
  * @param irn  the node
  */
-static ir_node *get_leader(node_t *node) {
+static ir_node *get_leader(node_t *node)
+{
 	partition_t *part = node->part;
 
 	if (part->n_leader > 1 || node->is_follower) {
@@ -2829,38 +3048,47 @@ static ir_node *get_leader(node_t *node) {
 	return node->node;
 }  /* get_leader */
 
+/**
+ * Returns non-zero if a mode_T node has only one reachable output.
+ */
+static int only_one_reachable_proj(ir_node *n)
+{
+	int i, k = 0;
+
+	for (i = get_irn_n_outs(n) - 1; i >= 0; --i) {
+		ir_node *proj = get_irn_out(n, i);
+		node_t  *node;
+
+		/* skip non-control flow Proj's */
+		if (get_irn_mode(proj) != mode_X)
+			continue;
+
+		node = get_irn_node(proj);
+		if (node->type.tv == tarval_reachable) {
+			if (++k > 1)
+				return 0;
+		}
+	}
+	return 1;
+}  /* only_one_reachable_proj */
+
 /**
  * Return non-zero if the control flow predecessor node pred
  * is the only reachable control flow exit of its block.
  *
- * @param pred  the control flow exit
+ * @param pred   the control flow exit
+ * @param block  the destination block
  */
-static int can_exchange(ir_node *pred) {
-	if (is_Start(pred))
+static int can_exchange(ir_node *pred, ir_node *block)
+{
+	if (is_Start(pred) || has_Block_entity(block))
 		return 0;
 	else if (is_Jmp(pred))
 		return 1;
 	else if (get_irn_mode(pred) == mode_T) {
-		int i, k;
-
 		/* if the predecessor block has more than one
 		   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);
-			node_t  *node;
-
-			/* skip non-control flow Proj's */
-			if (get_irn_mode(proj) != mode_X)
-				continue;
-
-			node = get_irn_node(proj);
-			if (node->type.tv == tarval_reachable) {
-				if (++k > 1)
-					return 0;
-			}
-		}
-		return 1;
+		return only_one_reachable_proj(pred);
 	}
 	return 0;
 }  /* can_exchange */
@@ -2869,8 +3097,9 @@ static int can_exchange(ir_node *pred) {
  * Block Post-Walker, apply the analysis results on control flow by
  * shortening Phi's and Block inputs.
  */
-static void apply_cf(ir_node *block, void *ctx) {
-	environment_t *env = ctx;
+static void apply_cf(ir_node *block, void *ctx)
+{
+	environment_t *env = (environment_t*)ctx;
 	node_t        *node = get_irn_node(block);
 	int           i, j, k, n;
 	ir_node       **ins, **in_X;
@@ -2919,7 +3148,7 @@ static void apply_cf(ir_node *block, void *ctx) {
 		/* only one predecessor combine */
 		ir_node *pred = skip_Proj(get_Block_cfgpred(block, 0));
 
-		if (can_exchange(pred)) {
+		if (can_exchange(pred, block)) {
 			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);
@@ -2961,6 +3190,7 @@ static void apply_cf(ir_node *block, void *ctx) {
 	if (k >= n)
 		return;
 
+	/* fix Phi's */
 	NEW_ARR_A(ir_node *, ins, n);
 	for (phi = get_Block_phis(block); phi != NULL; phi = next) {
 		node_t *node = get_irn_node(phi);
@@ -2968,8 +3198,8 @@ static void apply_cf(ir_node *block, void *ctx) {
 		next = get_Phi_next(phi);
 		if (is_tarval(node->type.tv) && tarval_is_constant(node->type.tv)) {
 			/* this Phi is replaced by a constant */
-			tarval  *tv = node->type.tv;
-			ir_node *c  = new_r_Const(current_ir_graph, block, get_tarval_mode(tv), tv);
+			ir_tarval *tv = node->type.tv;
+			ir_node   *c  = new_r_Const(current_ir_graph, tv);
 
 			set_irn_node(c, node);
 			node->node = c;
@@ -3004,21 +3234,22 @@ static void apply_cf(ir_node *block, void *ctx) {
 		}
 	}
 
+	/* fix block */
 	if (k == 1) {
 		/* this Block has only one live predecessor */
 		ir_node *pred = skip_Proj(in_X[0]);
 
-		if (can_exchange(pred)) {
+		if (can_exchange(pred, block)) {
 			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;
+			return;
 		}
-	} else {
-		set_irn_in(block, k, in_X);
-		env->modified = 1;
 	}
+	set_irn_in(block, k, in_X);
+	env->modified = 1;
 }  /* apply_cf */
 
 /**
@@ -3027,26 +3258,95 @@ static void apply_cf(ir_node *block, void *ctx) {
  * 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) {
+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
+		/* The conv is a no-op, so we are free to place it
 		 * either in the block of the leader OR in irn's block.
-		 * Propably placing it into leaders block might reduce
+		 * Probably 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);
+		ir_node  *nlead = new_rd_Conv(dbg, block, leader, mode);
+
+		if (nlead != leader) {
+			/* Note: this newly create irn has no node info because
+			 * it is created after the analysis. However, this node
+			 * replaces the node irn and should not be visited again,
+			 * so set its visited count to the count of irn.
+			 * Otherwise we might visited this node more than once if
+			 * irn had more than one user.
+			 */
+			set_irn_node(nlead, NULL);
+			set_irn_visited(nlead, get_irn_visited(irn));
+			leader = nlead;
+		}
 	}
 	exchange(irn, leader);
-}
+}  /* exchange_leader */
+
+/**
+ * Check, if all users of a mode_M node are dead. Use
+ * the Def-Use edges for this purpose, as they still
+ * reflect the situation.
+ */
+static int all_users_are_dead(const ir_node *irn)
+{
+	int i, n = get_irn_n_outs(irn);
+
+	for (i = 1; i <= n; ++i) {
+		const ir_node *succ  = irn->out[i].use;
+		const node_t  *block = get_irn_node(get_nodes_block(succ));
+		const node_t  *node;
+
+		if (block->type.tv == tarval_unreachable) {
+			/* block is unreachable */
+			continue;
+		}
+		node = get_irn_node(succ);
+		if (node->type.tv != tarval_top) {
+			/* found a reachable user */
+			return 0;
+		}
+	}
+	/* all users are unreachable */
+	return 1;
+}  /* all_user_are_dead */
+
+/**
+ * Walker: Find reachable mode_M nodes that have only
+ * unreachable users. These nodes must be kept later.
+ */
+static void find_kept_memory(ir_node *irn, void *ctx)
+{
+	environment_t *env = (environment_t*)ctx;
+	node_t        *node, *block;
+
+	if (get_irn_mode(irn) != mode_M)
+		return;
+
+	block = get_irn_node(get_nodes_block(irn));
+	if (block->type.tv == tarval_unreachable)
+		return;
+
+	node = get_irn_node(irn);
+	if (node->type.tv == tarval_top)
+		return;
+
+	/* ok, we found a live memory node. */
+	if (all_users_are_dead(irn)) {
+		DB((dbg, LEVEL_1, "%+F must be kept\n", irn));
+		ARR_APP1(ir_node *, env->kept_memory, irn);
+	}
+}  /* find_kept_memory */
 
 /**
  * Post-Walker, apply the analysis results;
  */
-static void apply_result(ir_node *irn, void *ctx) {
-	environment_t *env = ctx;
+static void apply_result(ir_node *irn, void *ctx)
+{
+	environment_t *env = (environment_t*)ctx;
 	node_t        *node = get_irn_node(irn);
 
 	if (is_Block(irn) || is_End(irn) || is_Bad(irn)) {
@@ -3064,17 +3364,39 @@ static void apply_result(ir_node *irn, void *ctx) {
 			DB((dbg, LEVEL_1, "%+F is unreachable\n", irn));
 			exchange(irn, bad);
 			env->modified = 1;
-		}
-		else if (node->type.tv == tarval_unreachable) {
-			/* don't kick away Unknown */
-			if (! is_Unknown(irn)) {
-				ir_node *bad = get_irg_bad(current_ir_graph);
+		} else if (node->type.tv == tarval_top) {
+			ir_mode *mode = get_irn_mode(irn);
+
+			if (mode == mode_M) {
+				/* never kill a mode_M node */
+				if (is_Proj(irn)) {
+					ir_node *pred  = get_Proj_pred(irn);
+					node_t  *pnode = get_irn_node(pred);
+
+					if (pnode->type.tv == tarval_top) {
+						/* skip the predecessor */
+						ir_node *mem = get_memop_mem(pred);
+						node->node = mem;
+						DB((dbg, LEVEL_1, "%+F computes Top, replaced by %+F\n", irn, mem));
+						exchange(irn, mem);
+						env->modified = 1;
+					}
+				}
+				/* leave other nodes, especially PhiM */
+			} else if (mode == mode_T) {
+				/* Do not kill mode_T nodes, kill their Projs */
+			} else if (! is_Unknown(irn)) {
+				/* don't kick away Unknown's, they might be still needed */
+				ir_node *unk = new_r_Unknown(current_ir_graph, mode);
+
+				/* control flow should already be handled at apply_cf() */
+				assert(mode != mode_X);
 
 				/* see comment above */
-				set_irn_node(bad, node);
-				node->node = bad;
-				DB((dbg, LEVEL_1, "%+F is unreachable\n", irn));
-				exchange(irn, bad);
+				set_irn_node(unk, node);
+				node->node = unk;
+				DB((dbg, LEVEL_1, "%+F computes Top\n", irn));
+				exchange(irn, unk);
 				env->modified = 1;
 			}
 		}
@@ -3084,24 +3406,31 @@ static void apply_result(ir_node *irn, void *ctx) {
 				ir_node *cond = get_Proj_pred(irn);
 
 				if (is_Cond(cond)) {
-					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 and the Proj is reachable, make a Jmp */
-						ir_node *jmp  = new_r_Jmp(current_ir_graph, block->node);
+					if (only_one_reachable_proj(cond)) {
+						ir_node *jmp = new_r_Jmp(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;
+					} else {
+						node_t    *sel = get_irn_node(get_Cond_selector(cond));
+						ir_tarval *tv  = sel->type.tv;
+
+						if (is_tarval(tv) && tarval_is_constant(tv)) {
+							/* The selector is a constant, but more
+							 * than one output is active: An unoptimized
+							 * case found. */
+							env->unopt_cf = 1;
+						}
 					}
 				}
 			}
 		} else {
 			/* normal data node */
 			if (is_tarval(node->type.tv) && tarval_is_constant(node->type.tv)) {
-				tarval *tv = node->type.tv;
+				ir_tarval *tv = node->type.tv;
 
 				/*
 				 * Beware: never replace mode_T nodes by constants. Currently we must mark
@@ -3109,7 +3438,7 @@ static void apply_result(ir_node *irn, void *ctx) {
 				 */
 				if (! is_Const(irn) && get_irn_mode(irn) != mode_T) {
 					/* can be replaced by a constant */
-					ir_node *c = new_r_Const(current_ir_graph, block->node, get_tarval_mode(tv), tv);
+					ir_node *c = new_r_Const(current_ir_graph, tv);
 					set_irn_node(c, node);
 					node->node = c;
 					DB((dbg, LEVEL_1, "%+F is replaced by %+F\n", irn, c));
@@ -3120,7 +3449,7 @@ static void apply_result(ir_node *irn, void *ctx) {
 			} else if (is_entity(node->type.sym.entity_p)) {
 				if (! is_SymConst(irn)) {
 					/* 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);
+					ir_node *symc = new_r_SymConst(current_ir_graph, get_irn_mode(irn), node->type.sym, symconst_addr_ent);
 					set_irn_node(symc, node);
 					node->node = symc;
 
@@ -3135,13 +3464,33 @@ static void apply_result(ir_node *irn, void *ctx) {
 				ir_node *leader = get_leader(node);
 
 				if (leader != irn) {
-					DB((dbg, LEVEL_1, "%+F from part%d is replaced by %+F\n", irn, node->part->nr, 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;
+					int non_strict_phi = 0;
+
+					/*
+					 * Beware: Do not remove Phi(Unknown, ..., x, ..., Unknown)
+					 * as this might create non-strict programs.
+					 */
+					if (node->is_follower && is_Phi(irn) && !is_Unknown(leader)) {
+						int i;
+
+						for (i = get_Phi_n_preds(irn) - 1; i >= 0; --i) {
+							ir_node *pred = get_Phi_pred(irn, i);
+
+							if (is_Unknown(pred)) {
+								non_strict_phi = 1;
+								break;
+							}
+						}
+					}
+					if (! non_strict_phi) {
+						DB((dbg, LEVEL_1, "%+F from part%d is replaced by %+F\n", irn, node->part->nr, 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;
+					}
 				}
 			}
 		}
@@ -3151,9 +3500,10 @@ static void apply_result(ir_node *irn, void *ctx) {
 /**
  * Fix the keep-alives by deleting unreachable ones.
  */
-static void apply_end(ir_node *end, environment_t *env) {
+static void apply_end(ir_node *end, environment_t *env)
+{
 	int i, j,  n = get_End_n_keepalives(end);
-	ir_node **in;
+	ir_node **in = NULL;
 
 	if (n > 0)
 		NEW_ARR_A(ir_node *, in, n);
@@ -3180,11 +3530,12 @@ static void apply_end(ir_node *end, environment_t *env) {
 /**
  * sets the generic functions to compute.
  */
-static void set_compute_functions(void) {
-	int i;
+static void set_compute_functions(void)
+{
+	size_t i, n;
 
 	/* set the default compute function */
-	for (i = get_irp_n_opcodes() - 1; i >= 0; --i) {
+	for (i = 0, n = get_irp_n_opcodes(); i < n; ++i) {
 		ir_op *op = get_irp_opcode(i);
 		op->ops.generic = (op_func)default_compute;
 	}
@@ -3202,30 +3553,44 @@ static void set_compute_functions(void) {
 	SET(Cmp);
 	SET(Proj);
 	SET(Confirm);
+	SET(Return);
 	SET(End);
+	SET(Call);
+}  /* set_compute_functions */
 
-	if (op_Max != NULL)
-		SET(Max);
-	if (op_Min != NULL)
-		SET(Min);
+/**
+ * Add memory keeps.
+ */
+static void add_memory_keeps(ir_node **kept_memory, size_t len)
+{
+	ir_node      *end = get_irg_end(current_ir_graph);
+	int          i;
+	size_t       idx;
+	ir_nodeset_t set;
 
-}  /* set_compute_functions */
+	ir_nodeset_init(&set);
 
-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);
+	/* check, if those nodes are already kept */
+	for (i = get_End_n_keepalives(end) - 1; i >= 0; --i)
+		ir_nodeset_insert(&set, get_End_keepalive(end, i));
 
-	ir_fprintf(F, "info2 : \"partition %u type %+F\"\n", node->part->nr, node->type);
-	return 1;
-#endif
-}
+	for (idx = 0; idx < len; ++idx) {
+		ir_node *ka = kept_memory[idx];
 
-void combo(ir_graph *irg) {
+		if (! ir_nodeset_contains(&set, ka)) {
+			add_End_keepalive(end, ka);
+		}
+	}
+	ir_nodeset_destroy(&set);
+}  /* add_memory_keeps */
+
+void combo(ir_graph *irg)
+{
 	environment_t env;
 	ir_node       *initial_bl;
 	node_t        *start;
 	ir_graph      *rem = current_ir_graph;
+	size_t        len;
 
 	current_ir_graph = irg;
 
@@ -3243,12 +3608,14 @@ void combo(ir_graph *irg) {
 	env.dbg_list       = NULL;
 #endif
 	env.opcode2id_map  = new_set(cmp_opcode, iro_Last * 4);
-	env.type2id_map    = pmap_create();
+	env.kept_memory    = NEW_ARR_F(ir_node *, 0);
 	env.end_idx        = get_opt_global_cse() ? 0 : -1;
 	env.lambda_input   = 0;
-	env.nonstd_cond    = 0;
-	env.commutative    = 1;
 	env.modified       = 0;
+	env.unopt_cf       = 0;
+	/* options driving the optimization */
+	env.commutative    = 1;
+	env.opt_unknown    = 1;
 
 	assure_irg_outs(irg);
 	assure_cf_loop(irg);
@@ -3259,18 +3626,20 @@ void combo(ir_graph *irg) {
 	set_compute_functions();
 	DEBUG_ONLY(part_nr = 0);
 
-	ir_reserve_resources(irg, IR_RESOURCE_IRN_LINK);
+	ir_reserve_resources(irg, IR_RESOURCE_IRN_LINK | IR_RESOURCE_PHI_LIST);
+
+	if (env.opt_unknown)
+		tarval_UNKNOWN = tarval_top;
+	else
+		tarval_UNKNOWN = tarval_bad;
 
 	/* 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);
+	irg_walk_graph(irg, create_initial_partitions, init_block_phis, &env);
 
-#ifdef WITH_UNKNOWN
-	tarval_UNKNOWN = env.nonstd_cond ? tarval_bad : tarval_top;
-#else
-	tarval_UNKNOWN = tarval_bad;
-#endif
+	/* set the hook: from now, every node has a partition and a type */
+	DEBUG_ONLY(set_dump_node_vcgattr_hook(dump_partition_hook));
 
 	/* all nodes on the initial partition have type Top */
 	env.initial->type_is_T_or_C = 1;
@@ -3291,17 +3660,29 @@ void combo(ir_graph *irg) {
 	check_all_partitions(&env);
 
 #if 0
-	set_dump_node_vcgattr_hook(dump_partition_hook);
 	dump_ir_block_graph(irg, "-partition");
-	set_dump_node_vcgattr_hook(NULL);
-#else
-	(void)dump_partition_hook;
 #endif
 
 	/* apply the result */
+
+	/* check, which nodes must be kept */
+	irg_walk_graph(irg, NULL, find_kept_memory, &env);
+
+	/* kill unreachable control flow */
 	irg_block_walk_graph(irg, NULL, apply_cf, &env);
-	irg_walk_graph(irg, NULL, apply_result, &env);
+	/* Kill keep-alives of dead blocks: this speeds up apply_result()
+	 * and fixes assertion because dead cf to dead blocks is NOT removed by
+	 * apply_cf(). */
 	apply_end(get_irg_end(irg), &env);
+	irg_walk_graph(irg, NULL, apply_result, &env);
+
+	len = ARR_LEN(env.kept_memory);
+	if (len > 0)
+		add_memory_keeps(env.kept_memory, len);
+
+	if (env.unopt_cf) {
+		DB((dbg, LEVEL_1, "Unoptimized Control Flow left"));
+	}
 
 	if (env.modified) {
 		/* control flow might changed */
@@ -3309,11 +3690,15 @@ void combo(ir_graph *irg) {
 		set_irg_extblk_inconsistent(irg);
 		set_irg_doms_inconsistent(irg);
 		set_irg_loopinfo_inconsistent(irg);
+		set_irg_entity_usage_state(irg, ir_entity_usage_not_computed);
 	}
 
-	ir_free_resources(irg, IR_RESOURCE_IRN_LINK);
+	ir_free_resources(irg, IR_RESOURCE_IRN_LINK | IR_RESOURCE_PHI_LIST);
 
-	pmap_destroy(env.type2id_map);
+	/* remove the partition hook */
+	DEBUG_ONLY(set_dump_node_vcgattr_hook(NULL));
+
+	DEL_ARR_F(env.kept_memory);
 	del_set(env.opcode2id_map);
 	obstack_free(&env.obst, NULL);
 
@@ -3321,3 +3706,9 @@ void combo(ir_graph *irg) {
 	set_value_of_func(NULL);
 	current_ir_graph = rem;
 }  /* combo */
+
+/* Creates an ir_graph pass for combo. */
+ir_graph_pass_t *combo_pass(const char *name)
+{
+	return def_graph_pass(name ? name : "combo", combo);
+}  /* combo_pass */