give Bad nodes a mode
[libfirm] / ir / opt / loop.c
index 091077f..7d88ca5 100644 (file)
@@ -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.
  *
  *
  * @version  $Id$
  */
-
 #include "config.h"
 
 #include "iroptimize.h"
 #include "opt_init.h"
 #include "irnode.h"
 #include "debug.h"
-
+#include "error.h"
 
 #include "ircons.h"
 #include "irgopt.h"
@@ -45,6 +44,7 @@
 #include "irpass.h"
 #include "irdom.h"
 
+#include <math.h>
 #include "irbackedge_t.h"
 #include "irphase_t.h"
 #include "irloop_t.h"
 
 DEBUG_ONLY(static firm_dbg_module_t *dbg);
 
+/* DBG print stats for every procedure.  */
+#define LOOP_OPT_STATS 1
+
+/* DBG: Ignore node limits and process every possible loop. */
+#define LOOP_IGNORE_NODE_LIMITS 0
+
 /**
  * Convenience macro for iterating over every phi node of the given block.
  * Requires phi list per block.
@@ -63,40 +69,32 @@ DEBUG_ONLY(static firm_dbg_module_t *dbg);
        for ((phi) = (head), (next) = (head) ? get_Phi_next((head)) : NULL; \
                        (phi) ; (phi) = (next), (next) = (next) ? get_Phi_next((next)) : NULL)
 
-/* currently processed loop */
+/* Currently processed loop. */
 static ir_loop *cur_loop;
 
-/* Condition for performing copy_walk. */
+/* Flag for kind of unrolling. */
+typedef enum {
+       constant,
+       invariant
+} unrolling_kind_flag;
+
+/* Condition for performing visiting a node during copy_walk. */
 typedef unsigned walker_condition(ir_node *);
 
-/* Node and position of a predecessor */
-typedef struct out_edge {
+/* Node and position of a predecessor. */
+typedef struct entry_edge {
        ir_node *node;
        int pos;
-} out_edge;
-
-/**/
-typedef struct inversion_node_info {
-       ir_node *copy;
-       ir_node **ins;
-       struct inversion_node_info *free_list_next;     /* linked list to free all node_infos */
-} inversion_node_info;
-
-/*   */
-typedef struct node_info {
-       ir_node **copy;
-       ir_node **ins;
-       struct ir_node *free_list_next;         /* linked list to free all node_infos */
-} node_info;
-
-/* Head of the list for freeing node_infos */
-static ir_node *free_list;
+       ir_node *pred;
+} entry_edge;
 
-/* A walker may start visiting the current loop with these nodes. */
-static out_edge *cur_loop_outs;
+/* Node info for unrolling. */
+typedef struct unrolling_node_info {
+       ir_node **copies;
+} unrolling_node_info;
 
 /* Outs of the nodes head. */
-static out_edge *cur_head_outs;
+static entry_edge *cur_head_outs;
 
 /* Information about the loop head */
 static ir_node *loop_head = NULL;
@@ -105,155 +103,157 @@ static unsigned loop_head_valid = 1;
 /* List of all inner loops, that are processed. */
 static ir_loop **loops;
 
-/* Inverted head */
-static ir_node *loop_inv_head = NULL;
-/* Peeled head */
-static ir_node *loop_peeled_head = NULL;
-
-/* Loop analysis informations */
-typedef struct loop_info_t {
-       unsigned blocks;                        /* number of blocks in the loop */
-       unsigned calls;                         /* number of calls */
-       unsigned cf_outs;
-       out_edge cf_out;
-       ir_node *new_loop_head;
-} loop_info_t;
-
-/* Information about the current loop */
-static loop_info_t loop_info;
-
-/* Outs of the condition chain (loop inversion). */
-static out_edge *cond_chain_entries;
-
-/* Arity of the unrolled loop heads. */
-static int unroll_arity;
-
-static ir_phase *phase;
+#if LOOP_OPT_STATS
 
+#define count_stats(val) (++val)
+#define print_stats() (do_print_stats())
+#define reset_stats() (do_reset_stats())
 
+/* Stats */
+typedef struct loop_stats_t {
+       unsigned loops;
+       unsigned inverted;
+       unsigned too_large;
+       unsigned too_large_adapted;
+       unsigned cc_limit_reached;
+       unsigned calls_limit;
 
-/* TODO */
-static unsigned head_inversion_node_count;
-static unsigned inversion_head_node_limit;
-static unsigned head_inversion_block_count;
+       unsigned u_simple_counting_loop;
+       unsigned constant_unroll;
+       unsigned invariant_unroll;
 
-static unsigned enable_peeling;
-static unsigned enable_inversion;
-static unsigned enable_unrolling;
+       unsigned unhandled;
+} loop_stats_t;
 
+static loop_stats_t stats;
 
-/* Creates node_info. A linked list keeps all node_infos to free them again. */
-static node_info *new_node_info(ir_node *node)
+/* Set stats to sero */
+static void do_reset_stats(void)
 {
-       node_info *l = XMALLOCZ(node_info);
-       l->free_list_next = free_list;
-       free_list = node;
-       l->copy = NULL;
-       return l;
+       memset(&stats, 0, sizeof(loop_stats_t));
 }
 
-/* Returns linked node_info for given node. */
-static node_info *get_node_info(ir_node *n)
+/* Print stats */
+static void do_print_stats(void)
 {
-       return ((node_info *)get_irn_link(n));
+       DB((dbg, LEVEL_2, "---------------------------------------\n"));
+       DB((dbg, LEVEL_2, "loops             :   %d\n",stats.loops));
+       DB((dbg, LEVEL_2, "inverted          :   %d\n",stats.inverted));
+       DB((dbg, LEVEL_2, "too_large         :   %d\n",stats.too_large));
+       DB((dbg, LEVEL_2, "too_large_adapted :   %d\n",stats.too_large_adapted));
+       DB((dbg, LEVEL_2, "cc_limit_reached  :   %d\n",stats.cc_limit_reached));
+       DB((dbg, LEVEL_2, "calls_limit       :   %d\n",stats.calls_limit));
+       DB((dbg, LEVEL_2, "u_simple_counting :   %d\n",stats.u_simple_counting_loop));
+       DB((dbg, LEVEL_2, "constant_unroll   :   %d\n",stats.constant_unroll));
+       DB((dbg, LEVEL_2, "invariant_unroll  :   %d\n",stats.invariant_unroll));
+       DB((dbg, LEVEL_2, "=======================================\n"));
 }
+#else
+/* No stats */
+#define count_stats(val) ((void)0)
+#define print_stats() ((void)0)
+#define reset_stats() ((void)0)
 
-/* Allocates a node_info struct for the given node */
-static void alloc_node_info(ir_node *node)
-{
-       node_info *state;
-       state = new_node_info(node);
-       set_irn_link(node, (void *)state);
-}
+#endif
 
-/* Frees node info and copy array for given node. Returns next node of free_list. */
-static ir_node *free_info(ir_node *node)
-{
-       node_info *info = get_node_info(node);
-       ir_node *next = info->free_list_next;
-       /*DB((dbg, LEVEL_1, "FREE %N\n", node));*/
-       DEL_ARR_F(info->copy);
-       xfree(info);
-       set_irn_link(node, NULL);
-       return next;
-}
+/* Commandline parameters */
+typedef struct loop_opt_params_t {
+unsigned max_loop_size;     /* Maximum number of nodes  [nodes]*/
+int      depth_adaption;    /* Loop nest depth adaption [percent] */
+unsigned allowed_calls;     /* Number of calls allowed [number] */
+unsigned count_phi:1;       /* Count phi nodes */
+unsigned count_proj:1;      /* Count projections */
 
-/* Free all created node_infos, including the copy arrays. */
-static void free_node_info(void)
-{
-       ir_node *node = free_list;
-       while (node) {
-               node = free_info(node);
-       }
-       free_list = NULL;
-}
+unsigned max_cc_size;       /* Maximum condition chain size [nodes] */
+unsigned max_branches;
 
-/* Free node_infos of blocks only, including the copy arrays. */
-static void free_node_info_blocks(void)
-{
-       ir_node *node = free_list;
-       ir_node *new_freelist = NULL;
-       while (node) {
-               ir_node *next;
-               if (is_Block(node)) {
-                       next = free_info(node);
-               } else {
-                       next = get_node_info(node)->free_list_next;
-                       get_node_info(node)->free_list_next = new_freelist;
-                       new_freelist = node;
-               }
-               node = next;
-       }
-       free_list = new_freelist;
-}
+unsigned max_unrolled_loop_size;    /* [nodes] */
+unsigned allow_const_unrolling:1;
+unsigned allow_invar_unrolling:1;
+unsigned invar_unrolling_min_size;  /* [nodes] */
 
-/* Reset nodes link. For use with a walker. */
-static void reset_link(ir_node *node, void *env)
-{
-       (void)env;
-       set_irn_link(node, NULL);
-}
+} loop_opt_params_t;
 
-static void set_inversion_copy(ir_node *n, ir_node *cp)
-{
-       phase_set_irn_data(phase, n, cp);
-}
+static loop_opt_params_t opt_params;
 
-/* Returns a nodes copy. */
-static ir_node *get_copy(ir_node *n, int index)
-{
-       ir_node *cp = ((node_info *)get_irn_link(n))->copy[index];
-       return cp;
-}
+/* Loop analysis informations */
+typedef struct loop_info_t {
+       unsigned nodes;        /* node count */
+       unsigned ld_st;        /* load and store nodes */
+       unsigned branches;     /* number of conditions */
+       unsigned calls;        /* number of calls */
+       unsigned cf_outs;      /* number of cf edges which leave the loop */
+       entry_edge cf_out;     /* single loop leaving cf edge */
+       int be_src_pos;        /* position of the single own backedge in the head */
+
+       /* for inversion */
+       unsigned cc_size;      /* nodes in the condition chain */
+
+       /* for unrolling */
+       unsigned max_unroll;   /* Number of unrolls satisfying max_loop_size */
+       unsigned exit_cond;    /* 1 if condition==true exits the loop.  */
+       unsigned latest_value:1;    /* 1 if condition is checked against latest counter value */
+       unsigned needs_backedge:1;  /* 0 if loop is completely unrolled */
+       unsigned decreasing:1;      /* Step operation is_Sub, or step is<0 */
+
+       /* IV informations of a simple loop */
+       ir_node *start_val;
+       ir_node *step;
+       ir_node *end_val;
+       ir_node *iteration_phi;
+       ir_node *add;
+
+       ir_tarval *count_tar;               /* Number of loop iterations */
+
+       ir_node *duff_cond;                 /* Duff mod */
+       unrolling_kind_flag unroll_kind;    /* constant or invariant unrolling */
+} loop_info_t;
 
-/* Returns a nodes copy if it exists, or else the node. */
-static ir_node *get_inversion_copy(ir_node *n)
-{
-       ir_node *cp = (ir_node *)phase_get_irn_data(phase, n);
-       return cp;
-}
+/* Information about the current loop */
+static loop_info_t loop_info;
 
-/* Returns a nodes copy, or node if there is no node info linked. */
-static ir_node *get_copy_safe(ir_node *node, int index)
-{
-       node_info *info = (node_info *)get_irn_link(node);
-       if (info != NULL)
-               return get_copy(node, index);
-       else
-               return node;
-}
+/* Outs of the condition chain (loop inversion). */
+static ir_node **cc_blocks;
+/* df/cf edges with def in the condition chain */
+static entry_edge *cond_chain_entries;
+/* Array of df loops found in the condition chain. */
+static entry_edge *head_df_loop;
+/* Number of blocks in cc */
+static unsigned inversion_blocks_in_cc;
+
+
+/* Cf/df edges leaving the loop.
+ * Called entries here, as they are used to enter the loop with walkers. */
+static entry_edge *loop_entries;
+/* Number of unrolls to perform */
+static int unroll_nr;
+/* Phase is used to keep copies of nodes. */
+static ir_phase *phase;
+
+/* Loop operations.  */
+typedef enum loop_op_t {
+       loop_op_inversion,
+       loop_op_unrolling,
+       loop_op_peeling
+} loop_op_t;
 
-/* Assigns the given array to a nodes node_info */
-static void set_copy_arr(ir_node *n, ir_node **arr)
+/* Saves which loop operation to do until after basic tests. */
+static loop_op_t loop_op;
+
+/* Returns the maximum nodes for the given nest depth */
+static unsigned get_max_nodes_adapted(unsigned depth)
 {
-       ((node_info *)get_irn_link(n))->copy = arr;
+       double perc = 100.0 + (double)opt_params.depth_adaption;
+       double factor = pow(perc / 100.0, depth);
+
+       return (int)((double)opt_params.max_loop_size * factor);
 }
 
-/* Assigns a copy with given index to a node.
- * Prerequirements are existing node_info and copy array. */
-static void set_copy(ir_node *n, int index, ir_node *copy)
+/* Reset nodes link. For use with a walker. */
+static void reset_link(ir_node *node, void *env)
 {
-       ((node_info *)get_irn_link(n))->copy[index] = copy;
+       (void)env;
+       set_irn_link(node, NULL);
 }
 
 /* Returns 0 if the node or block is not in cur_loop. */
@@ -262,262 +262,14 @@ static unsigned is_in_loop(ir_node *node)
        return (get_irn_loop(get_block(node)) == cur_loop);
 }
 
-/* Returns if the given be is an alien edge.
- * This is the case when the pred is not in the loop. */
-static unsigned is_alien_edge(ir_node *n, int i)
-{
-       return(!is_in_loop(get_irn_n(n, i)));
-}
-
+/* Returns 0 if the given edge is not a backedge
+ * with its pred in the cur_loop. */
 static unsigned is_own_backedge(ir_node *n, int pos)
 {
        return (is_backedge(n, pos) && is_in_loop(get_irn_n(n, pos)));
 }
 
-/* Resets block mark for given node. For use with walker */
-static void reset_block_mark(ir_node *node, void * env)
-{
-       (void) env;
-
-       if (is_Block(node))
-               set_Block_mark(node, 0);
-}
-
-static unsigned is_nodes_block_marked(ir_node* node)
-{
-       if (is_Block(node))
-               return get_Block_mark(node);
-       else
-               return get_Block_mark(get_block(node));
-}
-
-/* Returns the number of blocks in a loop. */
-static int get_loop_n_blocks(ir_loop *loop)
-{
-       int elements, e;
-       int blocks = 0;
-       elements = get_loop_n_elements(loop);
-
-       for (e=0; e<elements; e++) {
-               loop_element elem = get_loop_element(loop, e);
-               if (is_ir_node(elem.kind) && is_Block(elem.node))
-                       ++blocks;
-       }
-       return blocks;
-}
-
-/* */
-static void extend_ins_by_copy(ir_node *block, int pos)
-{
-       ir_node **ins;
-       ir_node *phi;
-       int i;
-       int arity = get_irn_arity(block);
-       int new_arity = arity + 1;
-       assert(is_Block(block));
-
-       NEW_ARR_A(ir_node *, ins, new_arity);
-
-       /* Extend block by copy of definition at pos */
-       for(i = 0; i < arity; ++i) {
-               ins[i] = get_irn_n(block, i);
-       }
-       ins[i] = get_inversion_copy(get_irn_n(block, pos));
-
-       DB((dbg, LEVEL_5, "Extend block %N by %N\n", block, ins[i]));
-
-       /* Fixes backedges. We rely on correct backedges. */
-       set_irn_in(block, new_arity, ins);
-
-       /* Extend block phis by copy of definition at pos */
-       for_each_phi(block, phi) {
-               ir_node *cp, *pred;
-               for(i = 0; i < arity; ++i)
-                       ins[i] = get_irn_n(phi, i);
-               pred = get_irn_n(phi, pos);
-               cp = get_inversion_copy(pred);
-               /* If the phis in is not in the condition chain (eg. a constant),
-                * there is no copy. */
-               if (cp == NULL)
-                       ins[i] = pred;
-               else
-                       ins[i] = cp;
-
-               DB((dbg, LEVEL_5, "Extend phi %N by %N\n", phi, ins[i]));
-               set_irn_in(phi, new_arity, ins);
-       }
-}
-
-/*
- * Extends all blocks which succeed the loop with the copied loops outs.
- * Also extends the blocks phis. Requires block phi list.
- * Returns an updated list of loop outs of the original loop outs.
- */
-static out_edge *extend_ins(out_edge *outs, int copies)
-{
-       ir_node **ins;
-       ir_node **phi_ins;
-       int *bes, *phi_bes;
-       ir_node *phi, *next_phi, *new_phi, *head, *new_block;
-       int old_arity, new_arity;
-       int i, c, p;
-       out_edge *new_outs;
-
-       inc_irg_visited(current_ir_graph);
-
-       new_outs = NEW_ARR_F(out_edge, 0);
-
-#if 0
-       for (i = 0; i < ARR_LEN(outs); ++i) {
-               out_edge edge = outs[i];
-               ir_node *node = edge.node;
-               DB((dbg, LEVEL_5, "outs %N %d\n", node, edge.pos));
-       }
-#endif
-
-       for (i = 0; i < ARR_LEN(outs); ++i) {
-               out_edge edge = outs[i];
-               ir_node *node = edge.node;
-               int in_c, positions_n;
-               int *positions;
-
-               if (!is_Block(node) && !is_Bad(node)) {
-#if 0
-                       if (is_Phi(node)) {
-                               int c;
-                               unsigned b = 0;
-                               ir_node *p = get_nodes_block(node);
-                               for(c = 0; c < get_irn_arity(p); ++c) {
-                                       if (is_in_loop(get_irn_n(p, c))) {
-                                               b=1;
-                                               break;
-                                       }
-                               }
-                               if (!b) {
-                                       ARR_APP1(out_edge, new_outs, edge);
-                                       DB((dbg, LEVEL_5, "new out %N\n", node));
-                               }
-
-                       } else {
-#endif
-                       ARR_APP1(out_edge, new_outs, edge);
-                       DB((dbg, LEVEL_5, "new out %N\n", node));
-
-               }
-
-               /* CONTINUE if node already processed. */
-               if (irn_visited(node))
-                       continue;
-
-               if (!is_Block(node))
-                       continue;
-
-               positions = NEW_ARR_F(int, 0);
-               positions_n = 0;
-
-               /* Search for all occurences of the current node, and save the in positions. */
-               for (p = 0; p < ARR_LEN(outs); ++p) {
-                       ir_node *cur = outs[p].node;
-                       int d_pos = outs[p].pos;
-
-                       if (node==cur) {
-                               DB((dbg, LEVEL_5, "Loop successor %N with pred @%d in loop\n",
-                                                       node, d_pos));
-                               ARR_APP1(int, positions, d_pos);
-                               mark_irn_visited(cur);
-                               ++positions_n;
-                       }
-               }
-
-               old_arity = get_irn_arity(node);
-               new_arity = old_arity + (positions_n * copies);
-
-               ins = NEW_ARR_F(ir_node*, new_arity);
-               bes = NEW_ARR_F(int, new_arity);
-
-               /* extend block ins */
-               for (in_c = 0; in_c < old_arity; ++in_c) {
-                       ins[in_c] = get_irn_n(node, in_c);
-                       bes[in_c] = is_backedge(node, in_c);
-               }
-               for (p = 0; p < positions_n; ++p) {
-                       for (c = 0; c < copies; ++c) {
-                               ir_node *cp = get_copy_safe(get_irn_n(node, positions[p]), c);
-                               DB((dbg, LEVEL_5, "%N (new_arity %d) @%d = %N\n",
-                                                       node, new_arity, in_c, cp));
-                               ins[in_c] = cp;
-                               bes[in_c] = is_backedge(node, positions[p]);
-                               ++in_c;
-                       }
-               }
-
-               assert(new_arity == in_c);
-
-               head = get_Block_phis(node);
-               new_block = new_r_Block(get_irn_irg(node), new_arity, ins);
-               set_irn_loop(new_block, get_irn_loop(node));
-
-               for (in_c = 0; in_c < new_arity; ++in_c) {
-                       if (bes[in_c])
-                               set_backedge(new_block, in_c);
-               }
-               DEL_ARR_F(ins);
-               DEL_ARR_F(bes);
-
-#if 1
-               set_Block_phis(node, NULL);
-
-               phi_ins = NEW_ARR_F(ir_node *, new_arity);
-               phi_bes = NEW_ARR_F(int, new_arity);
-
-               for_each_phi_safe(head, phi, next_phi) {
-                       for (in_c = 0; in_c < old_arity; ++in_c) {
-                               phi_ins[in_c] = get_irn_n(phi, in_c);
-                               phi_bes[in_c] = is_backedge(phi, in_c);
-                       }
-
-                       for (p = 0; p < positions_n; ++p) {
-                               for(c = 0; c < copies; ++c) {
-                                       ir_node *cp, *pred;
-                                       pred = get_irn_n(phi, positions[p]);
-                                       DB((dbg, LEVEL_5, "Phi %N pred @%d is %N\n",
-                                                               phi, positions[p], pred));
-                                       cp = get_copy_safe(pred, c);
-                                       phi_ins[in_c] = cp;
-                                       DB((dbg, LEVEL_5, "Phi %N in %d is %N\n",
-                                                               phi, in_c, cp));
-                                       phi_bes[in_c] = is_backedge(phi, positions[p]);
-                                       ++in_c;
-                               }
-                       }
-
-                       new_phi = new_r_Phi(new_block, new_arity, phi_ins, get_irn_mode(phi));
-
-                       for (in_c = 0; in_c < new_arity; ++in_c) {
-                               if (phi_bes[in_c])
-                                       set_backedge(new_phi, in_c);
-                       }
-                       exchange(phi, new_phi);
-                       DB((dbg, LEVEL_5, "exch Phi %N  %N\n",phi, new_phi));
-
-                       add_Block_phi(new_block, new_phi);
-               }
-
-               DEL_ARR_F(phi_ins);
-               DEL_ARR_F(phi_bes);
-#endif
-               exchange(node, new_block);
-               set_Block_MacroBlock(new_block, new_block);
-               DB((dbg, LEVEL_5, "exch block %N  %N\n", node, new_block));
-
-               DEL_ARR_F(positions);
-       }
-       return new_outs;
-}
-
-/**
- * Finds loop head and loop_info.
- */
+/* Finds loop head and some loop_info as calls or else if necessary. */
 static void get_loop_info(ir_node *node, void *env)
 {
        unsigned node_in_loop, pred_in_loop;
@@ -531,52 +283,68 @@ static void get_loop_info(ir_node *node, void *env)
                pred_in_loop = is_in_loop(pred);
                node_in_loop = is_in_loop(node);
 
+               if (!node_in_loop && pred_in_loop && is_Block(node))
+               {
+                       entry_edge entry;
+                       entry.node = node;
+                       entry.pos = i;
+                       entry.pred = pred;
+                       /* Count cf outs */
+                       ++loop_info.cf_outs;
+                       loop_info.cf_out = entry;
+               }
+
                /* collect some loop information */
                if (node_in_loop) {
+                       if (is_Phi(node) && opt_params.count_phi)
+                               ++loop_info.nodes;
+                       else if (is_Proj(node) && opt_params.count_proj)
+                               ++loop_info.nodes;
+                       else if (!is_Confirm(node) && !is_Const(node) && !is_SymConst(node))
+                               ++loop_info.nodes;
+
+                       if (is_Load(node) || is_Store(node))
+                               ++loop_info.ld_st;
+
                        if (is_Call(node))
                                ++loop_info.calls;
+
                }
 
                /* Find the loops head/the blocks with cfpred outside of the loop */
-               if (is_Block(node) && node_in_loop && !pred_in_loop && loop_head_valid) {
-                       ir_node *cfgpred = get_Block_cfgpred(node, i);
-
-                       if (!is_in_loop(cfgpred)) {
-                               DB((dbg, LEVEL_5, "potential head %+F because inloop and pred %+F not inloop\n",
-                                                       node, pred));
-                               /* another head? We do not touch this. */
-                               if (loop_head && loop_head != node) {
-                                       loop_head_valid = 0;
-                               } else {
-                                       loop_head = node;
+               if (is_Block(node)) {
+                       const ir_edge_t *edge;
+                       unsigned outs_n = 0;
+
+                       /* Count innerloop branches */
+                       foreach_out_edge_kind(node, edge, EDGE_KIND_NORMAL) {
+                               if (is_Block(get_edge_src_irn(edge)) && is_in_loop(get_edge_src_irn(edge)))
+                                       ++outs_n;
+                       }
+                       if (outs_n > 1)
+                               ++loop_info.branches;
+
+                       if (node_in_loop && !pred_in_loop && loop_head_valid) {
+                               ir_node *cfgpred = get_Block_cfgpred(node, i);
+
+                               if (!is_in_loop(cfgpred)) {
+                                       DB((dbg, LEVEL_5, "potential head %+F because inloop and pred %+F not inloop\n",
+                                                               node, pred));
+                                       /* another head? We do not touch this. */
+                                       if (loop_head && loop_head != node) {
+                                               loop_head_valid = 0;
+                                       } else {
+                                               loop_head = node;
+                                       }
                                }
                        }
                }
        }
 }
-/**/
-static void correct_phis(ir_node *node, void *env)
-{
-       (void)env;
-
-       if (is_Phi(node) && get_irn_arity(node) == 1) {
-               ir_node *exch;
-               ir_node *in[1];
-               in[0] = get_irn_n(node, 0);
-
-               exch = new_rd_Phi(get_irn_dbg_info(node),
-                       get_nodes_block(node), 1, in,
-                       get_irn_mode(node));
-
-               exchange(node, exch);
-               /* TODO make sure visited is copied */
-       }
-
-
-}
 
-/* Adds all nodes pointing into the loop to loop_entries and also finds the loops head */
-static void get_loop_outs(ir_node *node, void *env)
+/* Finds all edges with users outside of the loop
+ * and definition inside the loop. */
+static void get_loop_entries(ir_node *node, void *env)
 {
        unsigned node_in_loop, pred_in_loop;
        int i, arity;
@@ -590,30 +358,27 @@ static void get_loop_outs(ir_node *node, void *env)
                node_in_loop = is_in_loop(node);
 
                if (pred_in_loop && !node_in_loop) {
-                       out_edge entry;
+                       entry_edge entry;
                        entry.node = node;
                        entry.pos = i;
-                       ARR_APP1(out_edge, cur_loop_outs, entry);
-                       if (is_Block(node)) {
-                               ++loop_info.cf_outs;
-                               loop_info.cf_out = entry;
-                       }
-                       DB((dbg, LEVEL_5, "loop outs %N\n", node));
+                       entry.pred = pred;
+                       ARR_APP1(entry_edge, loop_entries, entry);
                }
        }
 }
 
+/* ssa */
 static ir_node *ssa_second_def;
 static ir_node *ssa_second_def_block;
 
 /**
  * Walks the graph bottom up, searching for definitions and creates phis.
  */
-static ir_node *search_def_and_create_phis(ir_node *block, ir_mode *mode)
+static ir_node *search_def_and_create_phis(ir_node *block, ir_mode *mode, int first)
 {
        int i;
        int n_cfgpreds;
-       ir_graph *irg;
+       ir_graph *irg = get_irn_irg(block);
        ir_node *phi;
        ir_node **in;
 
@@ -623,22 +388,21 @@ static ir_node *search_def_and_create_phis(ir_node *block, ir_mode *mode)
         * Dead and bad blocks. */
        if (get_irn_arity(block) < 1 || is_Bad(block)) {
                DB((dbg, LEVEL_5, "ssa bad %N\n", block));
-               return new_Bad();
+               return new_r_Bad(irg, mode);
        }
 
-       if (block == ssa_second_def_block) {
+       if (block == ssa_second_def_block && !first) {
                DB((dbg, LEVEL_5, "ssa found second definition: use second def %N\n", ssa_second_def));
                return ssa_second_def;
        }
 
        /* already processed this block? */
        if (irn_visited(block)) {
-               ir_node *value = get_irn_link(block);
+               ir_node *value = (ir_node *) get_irn_link(block);
                DB((dbg, LEVEL_5, "ssa already visited: use linked %N\n", value));
                return value;
        }
 
-       irg = get_irn_irg(block);
        assert(block != get_irg_start_block(irg));
 
        /* a Block with only 1 predecessor needs no Phi */
@@ -649,7 +413,7 @@ static ir_node *search_def_and_create_phis(ir_node *block, ir_mode *mode)
 
                DB((dbg, LEVEL_5, "ssa 1 pred: walk pred %N\n", pred_block));
 
-               value = search_def_and_create_phis(pred_block, mode);
+               value = search_def_and_create_phis(pred_block, mode, 0);
                set_irn_link(block, value);
                mark_irn_visited(block);
 
@@ -659,16 +423,12 @@ static ir_node *search_def_and_create_phis(ir_node *block, ir_mode *mode)
        /* create a new Phi */
        NEW_ARR_A(ir_node*, in, n_cfgpreds);
        for (i = 0; i < n_cfgpreds; ++i)
-               in[i] = new_Unknown(mode);
+               in[i] = new_r_Dummy(irg, mode);
 
        phi = new_r_Phi(block, n_cfgpreds, in, mode);
-
-
        /* Important: always keep block phi list up to date. */
        add_Block_phi(block, phi);
-
        DB((dbg, LEVEL_5, "ssa phi creation: link new phi %N to block %N\n", phi, block));
-
        set_irn_link(block, phi);
        mark_irn_visited(block);
 
@@ -677,15 +437,18 @@ static ir_node *search_def_and_create_phis(ir_node *block, ir_mode *mode)
                ir_node *pred_val;
                ir_node *pred_block = get_Block_cfgpred_block(block, i);
                assert(pred_block != NULL);
-               pred_val = search_def_and_create_phis(pred_block, mode);
+               pred_val = search_def_and_create_phis(pred_block, mode, 0);
+
                assert(pred_val != NULL);
 
                DB((dbg, LEVEL_5, "ssa phi pred:phi %N, pred %N\n", phi, pred_val));
                set_irn_n(phi, i, pred_val);
        }
+
        return phi;
 }
 
+
 /**
  * Given a set of values this function constructs SSA-form for the users of the
  * first value (the users are determined through the out-edges of the value).
@@ -702,7 +465,6 @@ static void construct_ssa(ir_node *orig_block, ir_node *orig_val,
        assert(orig_block && orig_val && second_block && second_val &&
                        "no parameter of construct_ssa may be NULL");
 
-       /* no need to do anything */
        if (orig_val == second_val)
                return;
 
@@ -733,12 +495,10 @@ static void construct_ssa(ir_node *orig_block, ir_node *orig_val,
 
                if (is_Phi(user)) {
                        ir_node *pred_block = get_Block_cfgpred_block(user_block, j);
-                       newval = search_def_and_create_phis(pred_block, mode);
+                       newval = search_def_and_create_phis(pred_block, mode, 1);
                } else {
-                       newval = search_def_and_create_phis(user_block, mode);
+                       newval = search_def_and_create_phis(user_block, mode, 1);
                }
-
-               /* If we get a bad node the user keeps the original in. No second definition needed. */
                if (newval != user && !is_Bad(newval))
                        set_irn_n(user, j, newval);
        }
@@ -747,96 +507,172 @@ static void construct_ssa(ir_node *orig_block, ir_node *orig_val,
 }
 
 
-/* Construct ssa for def and all of its copies.
- * NOTE: Overwrites links of blocks.
-*/
-static ir_node *construct_ssa_n(ir_node *def, ir_node *user, int copies)
-{
-       ir_graph *irg;
-       ir_mode *mode;
-       irg = get_irn_irg(def);
-       int i, user_arity;
-       ir_node *newval;
+/***** Unrolling Helper Functions *****/
 
-       ir_reserve_resources(irg, IR_RESOURCE_IRN_VISITED);
-       inc_irg_visited(current_ir_graph);
-       mode = get_irn_mode(def);
+/* Assign the copy with index nr to node n */
+static void set_unroll_copy(ir_node *n, int nr, ir_node *cp)
+{
+       unrolling_node_info *info;
+       assert(nr != 0 && "0 reserved");
 
-       set_irn_link(get_nodes_block(def), def);
-       mark_irn_visited(get_nodes_block(def));
+       info = (unrolling_node_info *)phase_get_irn_data(phase, n);
+       if (! info) {
+               ir_node **arr;
 
-       for (i = 0; i < copies; ++i) {
-               ir_node *cp = get_copy(def, i);
-               ir_node *block = get_nodes_block(cp);
-               set_irn_link(block, cp);
-               mark_irn_visited(block);
+               info = XMALLOCZ(unrolling_node_info);
+               arr = NEW_ARR_F(ir_node *, unroll_nr);
+               info->copies = arr;
+               memset(info->copies, 0, (unroll_nr) * sizeof(ir_node *));
 
-               DB((dbg, LEVEL_5, "ssa mark cp %N of def %N  usr %N\n", cp, def, user));
+               phase_set_irn_data(phase, n, info);
        }
+       /* Original node */
+       info->copies[0] = n;
 
-       /* TODO BUG BUG */
-       newval = user;
-       user_arity = get_irn_arity(user);
-       for (i = 0; i < user_arity; ++i) {
-               ir_node *user_block = get_nodes_block(user);
-               if (get_irn_n(user, i) != def)
-                       continue;
+       info->copies[nr] = cp;
+}
 
-               DB((dbg, LEVEL_5, "ssa_n found edge of user %N\n", user));
+/* Returns a nodes copy if it exists, else NULL. */
+static ir_node *get_unroll_copy(ir_node *n, int nr)
+{
+       ir_node             *cp;
+       unrolling_node_info *info = (unrolling_node_info *)phase_get_irn_data(phase, n);
+       if (! info)
+               return NULL;
 
-               if (is_Phi(user)) {
-                       ir_node *pred_block = get_Block_cfgpred_block(user_block, i);
-                       newval = search_def_and_create_phis(pred_block, mode);
-               } else {
-                       newval = search_def_and_create_phis(user_block, mode);
-               }
-               /*TODO bads should not happen! */
-               if (newval != user) {
-                       DB((dbg, LEVEL_5, "=> ssa_n new in is %N\n", newval));
-                       set_irn_n(user, i, newval);
-                       /*if (is_Phi(newval) && get_nodes_block(newval)== user_block) {
-                       ir_free_resources(irg, IR_RESOURCE_IRN_VISITED);
-                               return newval;
-                       }*/
-               }
+       cp = info->copies[nr];
+       return cp;
+}
 
-               /* BREAK, as we found and handled the definition */
-               break;
 
-#if 0
-               if (is_Bad(newval)) {
-                       DB((dbg, LEVEL_5, "=> ssa_n new in is BAD %N in graph %N\n", newval, current_ir_graph));
-                       add_End_keepalive(get_irg_end(current_ir_graph), newval);
-                       dump_ir_block_graph(current_ir_graph, "-bad");
-                       assert(0);
+/***** Inversion Helper Functions *****/
 
-               }
-#endif
-       }
+/* Sets copy cp of node n. */
+static void set_inversion_copy(ir_node *n, ir_node *cp)
+{
+       phase_set_irn_data(phase, n, cp);
+}
 
-       ir_free_resources(irg, IR_RESOURCE_IRN_VISITED);
-       return NULL;
+/* Getter of copy of n for inversion */
+static ir_node *get_inversion_copy(ir_node *n)
+{
+       ir_node *cp = (ir_node *)phase_get_irn_data(phase, n);
+       return cp;
 }
 
-/* Returns the number of backedges with or without alien bes. */
-static int get_backedge_n(ir_node *loophead, unsigned with_alien)
+/* Resets block mark for given node. For use with walker */
+static void reset_block_mark(ir_node *node, void * env)
 {
-       int i;
-       int be_n = 0;
-       int arity = get_irn_arity(loophead);
+       (void) env;
+
+       if (is_Block(node))
+               set_Block_mark(node, 0);
+}
+
+/* Returns mark of node, or its block if node is not a block.
+ * Used in this context to determine if node is in the condition chain. */
+static unsigned is_nodes_block_marked(ir_node* node)
+{
+       if (is_Block(node))
+               return get_Block_mark(node);
+       else
+               return get_Block_mark(get_block(node));
+}
+
+/* Extends a nodes ins by node new.
+ * NOTE: This is slow if a node n needs to be extended more than once. */
+static void extend_irn(ir_node *n, ir_node *newnode, int new_is_backedge)
+{
+       ir_node **ins;
+       int i;
+       int arity = get_irn_arity(n);
+       int new_arity = arity + 1;
+       int *bes;
+
+       NEW_ARR_A(int, bes, new_arity);
+       NEW_ARR_A(ir_node *, ins, new_arity);
+
+       /* save bes */
+       /* Bes are important!
+        * Another way would be recreating the looptree,
+        * but after that we cannot distinguish already processed loops
+        * from not yet processed ones. */
+       if (is_Block(n)) {
+               for(i = 0; i < arity; ++i) {
+                       bes[i] = is_backedge(n, i);
+               }
+               bes[i] = new_is_backedge;
+       }
+
+       for(i = 0; i < arity; ++i) {
+               ins[i] = get_irn_n(n, i);
+       }
+       ins[i] = newnode;
+
+       set_irn_in(n, new_arity, ins);
+
+       /* restore bes  */
+       if (is_Block(n)) {
+               for(i = 0; i < new_arity; ++i) {
+                       if (bes[i])
+                               set_backedge(n, i);
+               }
+       }
+}
+
+/* Extends a block by a copy of its pred at pos,
+ * fixing also the phis in the same way. */
+static void extend_ins_by_copy(ir_node *block, int pos)
+{
+       ir_node *new_in;
+       ir_node *phi;
+       ir_node *pred;
+       assert(is_Block(block));
+
+       /* Extend block by copy of definition at pos */
+       pred = get_irn_n(block, pos);
+       new_in = get_inversion_copy(pred);
+       DB((dbg, LEVEL_5, "Extend block %N by %N cp of %N\n", block, new_in, pred));
+       extend_irn(block, new_in, 0);
+
+       /* Extend block phis by copy of definition at pos */
+       for_each_phi(block, phi) {
+               ir_node *pred, *cp;
+
+               pred = get_irn_n(phi, pos);
+               cp = get_inversion_copy(pred);
+               /* If the phis in is not in the condition chain (eg. a constant),
+                * there is no copy. */
+               if (cp == NULL)
+                       new_in = pred;
+               else
+                       new_in = cp;
+
+               DB((dbg, LEVEL_5, "Extend phi %N by %N cp of %N\n", phi, new_in, pred));
+               extend_irn(phi, new_in, 0);
+       }
+}
+
+/* Returns the number of blocks backedges. With or without alien bes. */
+static int get_backedge_n(ir_node *block, unsigned with_alien)
+{
+       int i;
+       int be_n = 0;
+       int arity = get_irn_arity(block);
+
+       assert(is_Block(block));
+
        for (i = 0; i < arity; ++i) {
-               ir_node *pred = get_irn_n(loophead, i);
-               if (is_backedge(loophead, i) && (with_alien || is_in_loop(pred)))
+               ir_node *pred = get_irn_n(block, i);
+               if (is_backedge(block, i) && (with_alien || is_in_loop(pred)))
                        ++be_n;
        }
        return be_n;
 }
 
-/**
- * Returns a raw copy of the given node.
- * Attributes are kept/set according to the needs of loop inversion.
- */
-static ir_node *copy_node_inversion(ir_node *node)
+/* Returns a raw copy of the given node.
+ * Attributes are kept/set according to the needs of loop inversion. */
+static ir_node *copy_node(ir_node *node)
 {
        int i, arity;
        ir_node *cp;
@@ -844,19 +680,16 @@ static ir_node *copy_node_inversion(ir_node *node)
        cp = exact_copy(node);
        arity = get_irn_arity(node);
 
+       /* Keep backedge info */
        for (i = 0; i < arity; ++i) {
                if (is_backedge(node, i))
                        set_backedge(cp, i);
        }
 
-       set_inversion_copy(node, cp);
-       DB((dbg, LEVEL_5, "set copy of %N to cp %N \n", node, cp));
-
        if (is_Block(cp)) {
-               /* We may not keep the old macroblock. */
-               set_Block_MacroBlock(cp, cp);
                set_Block_mark(cp, 0);
        }
+
        return cp;
 }
 
@@ -864,10 +697,11 @@ static ir_node *copy_node_inversion(ir_node *node)
 /**
  * This walker copies all walked nodes.
  * If the walk_condition is true for a node, it is copied.
- * All nodes node_info copy attributes have to be NULL prior to every walk.
+ * All nodes node_info->copy have to be NULL prior to every walk.
+ * Order of ins is important for later usage.
  */
 static void copy_walk(ir_node *node, walker_condition *walk_condition,
-               ir_loop *set_loop)
+                      ir_loop *set_loop)
 {
        int i;
        int arity;
@@ -882,7 +716,9 @@ static void copy_walk(ir_node *node, walker_condition *walk_condition,
                /* Here we rely on nodestate's copy being initialized with NULL */
                DB((dbg, LEVEL_5, "copy_walk: We have already visited %N\n", node));
                if (get_inversion_copy(node) == NULL) {
-                       cp = copy_node_inversion(node);
+                       cp = copy_node(node);
+                       set_inversion_copy(node, cp);
+
                        DB((dbg, LEVEL_5, "The TEMP copy of %N is created %N\n", node, cp));
                }
                return;
@@ -919,7 +755,8 @@ static void copy_walk(ir_node *node, walker_condition *walk_condition,
        /* copy node / finalize temp node */
        if (get_inversion_copy(node) == NULL) {
                /* No temporary copy existent */
-               cp = copy_node_inversion(node);
+               cp = copy_node(node);
+               set_inversion_copy(node, cp);
                DB((dbg, LEVEL_5, "The FINAL copy of %N is CREATED %N\n", node, cp));
        } else {
                /* temporary copy is existent but without correct ins */
@@ -935,196 +772,143 @@ static void copy_walk(ir_node *node, walker_condition *walk_condition,
                        add_Block_phi(cpblock, cp);
        }
 
-       set_irn_loop(cp, set_loop);
-
        /* Keeps phi list of temporary node. */
        set_irn_in(cp, ARR_LEN(cpin), cpin);
 }
 
-/* Creates a new node from a given one, but with custom ins. */
-static ir_node *copy_node_changed(
-               ir_node *node, ir_node *block, int arity, ir_node **ins, ir_loop *loop)
+/**
+ * This walker copies all walked nodes.
+ * If the walk_condition is true for a node, it is copied.
+ * All nodes node_info->copy have to be NULL prior to every walk.
+ * Order of ins is important for later usage.
+ * Takes copy_index, to phase-link copy at specific index.
+ */
+static void copy_walk_n(ir_node *node, walker_condition *walk_condition,
+                        int copy_index)
 {
+       int i;
+       int arity;
        ir_node *cp;
-       DB((dbg, LEVEL_5, "New node from %N in %N block %N arity %d\n",
-                               node, get_irn_irg(node), block, arity));
-#if 0
-       if (is_Phi(node)) {
-               cp = new_rd_Phi(get_irn_dbg_info(node),
-                               block,
-                               arity,
-                               ins,
-                               get_irn_mode(node));
+       ir_node **cpin;
 
-       } else {
-#endif
-       /* We want to keep phi nodes with arity 1, as it makes rewiring a lot easier. */
-       cp = new_ir_node(get_irn_dbg_info(node),
-                       get_irn_irg(node),
-                       block,
-                       get_irn_op(node),
-                       get_irn_mode(node),
-                       arity,
-                       ins);
-
-       /* By any means, keep the blocks phi list up-to-date,
-          because regaining it would destroy the links. */
-       if (is_Phi(cp))
-               add_Block_phi(block, cp);
-/* TODO */
-       if (get_irn_op(node) == get_irn_op(cp))
-               copy_node_attr(get_irn_irg(node), node, cp);
-
-       /*new_backedge_info(cp); function removed */
-       if (is_Block(cp))
-               set_Block_MacroBlock(cp, cp);
-
-       set_irn_loop(cp, loop);
-
-       /* Blocks are copied first, so that future phi nodes populate the phi list. */
-       if (is_Block(cp))
-               set_Block_phis(cp, NULL);
-
-       DB((dbg, LEVEL_5, "New node %N in %N block %N arity %d\n",
-                               cp, get_irn_irg(cp), block, arity));
-       return cp;
-}
+       /**
+        * break condition and cycle resolver, creating temporary node copies
+        */
+       if (irn_visited(node)) {
+               /* Here we rely on nodestate's copy being initialized with NULL */
+               DB((dbg, LEVEL_5, "copy_walk: We have already visited %N\n", node));
+               if (get_unroll_copy(node, copy_index) == NULL) {
+                       ir_node *u;
+                       u = copy_node(node);
+                       set_unroll_copy(node, copy_index, u);
+                       DB((dbg, LEVEL_5, "The TEMP unknown of %N is created %N\n", node, u));
+               }
+               return;
+       }
 
-/* To be exchangeable, the unknown needs to have proper graph set. */
-static ir_node *new_node_unknown(ir_node *block, ir_mode *mode)
-{
-       ir_node *new = new_ir_node(NULL, get_irn_irg(block), block, op_Unknown, mode, 0, NULL);
-       return new;
-}
+       /* Walk */
+       mark_irn_visited(node);
 
-/**
- * Walker, to copy alle nodes that meet the walk_condition.
- * Blocks are copied first, which is important for the creation of the phi lists.
- *
- */
-static ir_node *copy_walk_n(ir_node *node, walker_condition *walk_condition, int copy_index, int alloc_cp_arr)
-{
-       int             i;
-       int             arity;
-       unsigned        headblock = 0;
-       ir_node         *block, *cp, *new_cp;
-       ir_node         **ins = NULL;
+       if (!is_Block(node)) {
+               ir_node *block = get_nodes_block(node);
+               if (walk_condition(block))
+                       DB((dbg, LEVEL_5, "walk block %N\n", block));
+               copy_walk_n(block, walk_condition, copy_index);
+       }
 
-       if (irn_visited(node)) {
-               cp = get_copy(node, copy_index);
+       arity = get_irn_arity(node);
+       NEW_ARR_A(ir_node *, cpin, arity);
 
-               DB((dbg, LEVEL_5, "Visited %N\n", node));
+       for (i = 0; i < arity; ++i) {
+               ir_node *pred = get_irn_n(node, i);
 
-               if (cp != NULL) {
-                       DB((dbg, LEVEL_5, "Visited. Return copy %N\n", cp));
-                       return cp;
+               if (walk_condition(pred)) {
+                       DB((dbg, LEVEL_5, "walk node %N\n", pred));
+                       copy_walk_n(pred, walk_condition, copy_index);
+                       cpin[i] = get_unroll_copy(pred, copy_index);
+               } else {
+                       cpin[i] = pred;
                }
+       }
 
-               if (!is_Block(node)) {
-                       ir_node *unknown = new_node_unknown(
-                                       get_nodes_block(node),
-                                       get_irn_mode(node));
-                       DB((dbg, LEVEL_5, " #### Create Unknown %N for %N\n", unknown, node));
-                       set_copy(node, copy_index, unknown);
-                       return unknown;
-               }
+       /* copy node / finalize temp node */
+       cp = get_unroll_copy(node, copy_index);
+       if (cp == NULL || is_Unknown(cp)) {
+               cp = copy_node(node);
+               set_unroll_copy(node, copy_index, cp);
+               DB((dbg, LEVEL_5, "The FINAL copy of %N is CREATED %N\n", node, cp));
        } else {
-               DB((dbg, LEVEL_5, "Walk %N\n", node));
-               mark_irn_visited(node);
-
-               /* Allocate array of copies */
-               if (alloc_cp_arr > 0) {
-                       ir_node **arr = NEW_ARR_F(ir_node *, alloc_cp_arr);
-                       alloc_node_info(node);
-                       for (i = 0; i < alloc_cp_arr; ++i)
-                               arr[i] = NULL;
-                       set_copy_arr(node, arr);
-               }
+               /* temporary copy is existent but without correct ins */
+               cp = get_unroll_copy(node, copy_index);
+               DB((dbg, LEVEL_5, "The FINAL copy of %N is EXISTENT %N\n", node, cp));
        }
 
-       block = NULL;
        if (!is_Block(node)) {
-               ir_node *orig_block = get_nodes_block(node);
-               DB((dbg, LEVEL_5, "current node: %N about to walk block %N\n", node, orig_block));
-               /* Check walk_condition for blocks not necessary */
-
-               if (orig_block == loop_head && is_Phi(node))
-                       headblock = 1;
+               ir_node *cpblock = get_unroll_copy(get_nodes_block(node), copy_index);
 
-               block = copy_walk_n(orig_block, walk_condition, copy_index, alloc_cp_arr);
-               DB((dbg, LEVEL_5, "current node: %N block %N blocks copy %N\n",
-                                       node, orig_block, block));
-       } else {
-               if (node == loop_head)
-                       headblock = 1;
+               set_nodes_block(cp, cpblock );
+               if (is_Phi(cp))
+                       add_Block_phi(cpblock, cp);
        }
 
+       /* Keeps phi list of temporary node. */
+       set_irn_in(cp, ARR_LEN(cpin), cpin);
+}
 
-       arity = get_irn_arity(node);
+/* Removes alle Blocks with non marked predecessors from the condition chain. */
+static void unmark_not_allowed_cc_blocks(void)
+{
+       size_t blocks = ARR_LEN(cc_blocks);
+       size_t i;
 
-       if (headblock) {
-               /* Headblock and headblock-phi case */
-               int in_c = 0;
-               DB((dbg, LEVEL_5, "Headblock/Phi from headblock\n"));
-               NEW_ARR_A(ir_node *, ins, unroll_arity);
+       for(i = 0; i < blocks; ++i) {
+               ir_node *block = cc_blocks[i];
+               int a;
+               int arity = get_irn_arity(block);
 
-               for (i = 0; i < arity; ++i) {
-                       ir_node *ret;
-                       ir_node *pred = get_irn_n(node, i);
-                       if (is_backedge(loop_head, i)) {
-                               if (walk_condition(pred)) {
-                                       ret = copy_walk_n(pred, walk_condition, copy_index, alloc_cp_arr);
-                                       DB((dbg, LEVEL_5, "in %d = %N walked\n", i, ret));
-                               } else {
-                                       ret = pred;
-                                       DB((dbg, LEVEL_5, "in %d = %N not walked\n", i, ret));
-                               }
-                               ins[in_c++] = ret;
-                       }
-               }
-               arity = unroll_arity;
-       } else {
-               /* Normal case */
-               NEW_ARR_A(ir_node *, ins, arity);
+               /* Head is an exception. */
+               if (block == loop_head)
+                       continue;
 
-               for (i = 0; i < arity; ++i) {
-                       ir_node *ret;
-                       ir_node *pred = get_irn_n(node, i);
-                       if (walk_condition(pred)) {
-                               ret = copy_walk_n(pred, walk_condition, copy_index, alloc_cp_arr);
-                               DB((dbg, LEVEL_5, "in %d = %N walked\n", i, ret));
-                       } else {
-                               ret = pred;
-                               DB((dbg, LEVEL_5, "in %d = %N not walked\n", i, ret));
+               for(a = 0; a < arity; ++a) {
+                       if (! is_nodes_block_marked(get_irn_n(block, a))) {
+                               set_Block_mark(block, 0);
+                               --inversion_blocks_in_cc;
+                               DB((dbg, LEVEL_5, "Removed %N from cc (blocks in cc %d)\n",
+                                               block, inversion_blocks_in_cc));
+
+                               break;
                        }
-                       ins[i] = ret;
                }
        }
+}
 
-       /* NOW, after the walk, we may check if the blocks copy is already present. */
-       cp = get_copy(node, copy_index);
-       if (cp != NULL && !is_Unknown(cp)) {
-               DB((dbg, LEVEL_5, "Must be Block %N copy is already present\n", node, cp));
-               assert(is_Block(cp) &&
-                               "sanity: The copy should have been a block.");
-               return cp;
-       }
+/* Unmarks all cc blocks using cc_blocks except head.
+ * TODO: invert head for unrolling? */
+static void unmark_cc_blocks(void)
+{
+       size_t blocks = ARR_LEN(cc_blocks);
+       size_t i;
 
-       new_cp = copy_node_changed(node, block, arity, ins, cur_loop);
-       set_copy(node, copy_index, new_cp);
+       for(i = 0; i < blocks; ++i) {
+               ir_node *block = cc_blocks[i];
 
-       if (cp != NULL && is_Unknown(cp)) {
-               DB((dbg, LEVEL_5, "Found unknown %N in %N now exchanged by %N in %N\n",
-                                       cp, get_irn_irg(cp), new_cp, get_irn_irg(new_cp)));
-               exchange(cp, new_cp);
+               /* TODO Head is an exception. */
+               /*if (block != loop_head)*/
+               set_Block_mark(block, 0);
        }
-       return new_cp;
+       /*inversion_blocks_in_cc = 1;*/
+       inversion_blocks_in_cc = 0;
+
+       /* invalidate */
+       loop_info.cc_size = 0;
 }
 
 /**
  * Populates head_entries with (node, pred_pos) tuple
- * whereas the node's pred at pred_pos is in the head but not the node itself.
- * Head and condition chain blocks must be marked.
+ * whereas the node's pred at pred_pos is in the cc but not the node itself.
+ * Also finds df loops inside the cc.
+ * Head and condition chain blocks have been marked previously.
  */
 static void get_head_outs(ir_node *node, void *env)
 {
@@ -1132,113 +916,137 @@ static void get_head_outs(ir_node *node, void *env)
        int arity = get_irn_arity(node);
        (void) env;
 
-       DB((dbg, LEVEL_5, "get head entries %N \n", node));
-
        for (i = 0; i < arity; ++i) {
-               /* node is not in the head, but the predecessor is.
-                * (head or loop chain nodes are marked) */
-
-               DB((dbg, LEVEL_5, "... "));
-               DB((dbg, LEVEL_5, "node %N  marked %d (0)  pred %d marked %d (1) \n",
-                                       node, is_nodes_block_marked(node), i,
-                                       is_nodes_block_marked(get_irn_n(node, i))));
-
                if (!is_nodes_block_marked(node) && is_nodes_block_marked(get_irn_n(node, i))) {
-                       out_edge entry;
+                       entry_edge entry;
                        entry.node = node;
                        entry.pos = i;
-                       ARR_APP1(out_edge, cur_head_outs, entry);
+                       /* Saving also predecessor seems redundant, but becomes
+                        * necessary when changing position of it, before
+                        * dereferencing it.*/
+                       entry.pred = get_irn_n(node, i);
+                       ARR_APP1(entry_edge, cur_head_outs, entry);
+               }
+       }
 
-                       if (is_in_loop(node) && is_Block(node)) {
-                               loop_info.new_loop_head = node;
-                               DB((dbg, LEVEL_5, " SET NEW LOOPHEAD to %N\n", node));
+       arity = get_irn_arity(loop_head);
+
+       /* Find df loops inside the cc */
+       if (is_Phi(node) && get_nodes_block(node) == loop_head) {
+               for (i = 0; i < arity; ++i) {
+                       if (is_own_backedge(loop_head, i)) {
+                               if (is_nodes_block_marked(get_irn_n(node, i))) {
+                                       entry_edge entry;
+                                       entry.node = node;
+                                       entry.pos = i;
+                                       entry.pred = get_irn_n(node, i);
+                                       ARR_APP1(entry_edge, head_df_loop, entry);
+                                       DB((dbg, LEVEL_5, "Found incc assignment node %N @%d is pred %N, graph %N %N\n",
+                                                       node, i, entry.pred, current_ir_graph, get_irg_start_block(current_ir_graph)));
+                               }
                        }
                }
        }
 }
 
 /**
- * Find condition chains, and add them to be inverted
+ * Find condition chains, and add them to be inverted.
  * A block belongs to the chain if a condition branches out of the loop.
+ * (Some blocks need to be removed once again.)
  * Returns 1 if the given block belongs to the condition chain.
  */
-static unsigned find_condition_chains(ir_node *block)
+static unsigned find_condition_chain(ir_node *block)
 {
-       const ir_edge_t *edge;
+       const    ir_edge_t *edge;
        unsigned mark = 0;
-       int nodes_n = 0;
+       unsigned has_be = 0;
+       unsigned jmp_only;
+       unsigned nodes_n = 0;
+
+       mark_irn_visited(block);
 
        DB((dbg, LEVEL_5, "condition_chains for block %N\n", block));
 
-       /* Collect all outs, including keeps. */
+       /* Get node count */
        foreach_out_edge_kind(block, edge, EDGE_KIND_NORMAL) {
                ++nodes_n;
        }
 
-       /* Leave at least one block as body. */
-       if (head_inversion_node_count + nodes_n > inversion_head_node_limit
-                       || head_inversion_block_count + 1 == loop_info.blocks) {
+       /* Check if node count would exceed maximum cc size.
+        * TODO
+        * This is not optimal, as we search depth-first and break here,
+        * continuing with another subtree. */
+       if (loop_info.cc_size + nodes_n > opt_params.max_cc_size) {
                set_Block_mark(block, 0);
-
                return 0;
        }
 
-       /* First: check our successors,
-        * and add all of them, which are outside of the loop, to the list */
-       foreach_block_succ(block, edge) {
-               ir_node *src = get_edge_src_irn( edge );
-               int pos = get_edge_src_pos( edge );
+       /* Check if block only has a jmp instruction. */
+       jmp_only = 1;
+       foreach_out_edge(block, edge) {
+               ir_node *src = get_edge_src_irn(edge);
 
-               if (!is_in_loop(src)) {
-                       out_edge entry;
+               if (! is_Block(src) && ! is_Jmp(src)) {
+                       jmp_only = 0;
+               }
+       }
+
+       /* Check cf outs if one is leaving the loop,
+        * or if this node has a backedge. */
+       foreach_block_succ(block, edge) {
+               ir_node *src = get_edge_src_irn(edge);
+               int pos = get_edge_src_pos(edge);
 
+               if (! is_in_loop(src))
                        mark = 1;
-                       entry.node = src;
-                       entry.pos = pos;
-                       ARR_APP1(out_edge, cond_chain_entries, entry);
-                       mark_irn_visited(src);
+
+               /* Inverting blocks with backedge outs leads to a cf edge
+                * from the inverted head, into the inverted head (skipping the body).
+                * As the body becomes the new loop head,
+                * this would introduce another loop in the existing loop.
+                * This loop inversion cannot cope with this case. */
+               if (is_backedge(src, pos)) {
+                       has_be = 1;
+                       break;
                }
        }
 
-       if (mark == 0) {
-               set_Block_mark(block, 0);
-               return 0;
-       } else {
+       /* We need all predecessors to already belong to the condition chain.
+        * Example of wrong case:  * == in cc
+        *
+        *     Head*             ,--.
+        *    /|   \            B   |
+        *   / A*  B           /    |
+        *  / /\   /          ?     |
+        *   /   C*      =>      D  |
+        *      /  D           Head |
+        *     /               A  \_|
+        *                      C
+        */
+       /* Collect blocks containing only a Jmp.
+        * Do not collect blocks with backedge outs. */
+       if ((jmp_only == 1 || mark == 1) && has_be == 0) {
                set_Block_mark(block, 1);
-               ++head_inversion_block_count;
+               ++inversion_blocks_in_cc;
+               loop_info.cc_size += nodes_n;
                DB((dbg, LEVEL_5, "block %N is part of condition chain\n", block));
-               head_inversion_node_count += nodes_n;
+               ARR_APP1(ir_node *, cc_blocks, block);
+       } else {
+               set_Block_mark(block, 0);
        }
 
-       /* Second: walk all successors,
-        * and add them to the list if they are not part of the chain */
        foreach_block_succ(block, edge) {
-               unsigned inchain;
                ir_node *src = get_edge_src_irn( edge );
-               int pos = get_edge_src_pos( edge );
-
-               /* already done */
-               if (!is_in_loop( src ) || irn_visited(src)) {
-                       continue;
-               }
 
-               mark_irn_visited(src);
-               DB((dbg, LEVEL_5, "condition chain walk %N\n", src));
-               inchain = find_condition_chains(src);
-
-               /* if successor is not part of chain we need to collect its outs */
-               if (!inchain) {
-                       out_edge entry;
-                       entry.node = src;
-                       entry.pos = pos;
-                       ARR_APP1(out_edge, cond_chain_entries, entry);
-               }
+               if (is_in_loop(src) && ! irn_visited(src))
+                       find_condition_chain(src);
        }
+
        return mark;
 }
 
 /**
- * Rewires the copied condition chain. Removes backedges.
+ * Rewires the copied condition chain. Removes backedges
  * as this condition chain is prior to the loop.
  * Copy of loop_head must have phi list and old (unfixed) backedge info of the loop head.
  * (loop_head is already fixed, we cannot rely on it.)
@@ -1249,10 +1057,11 @@ static void fix_copy_inversion(void)
        ir_node **ins;
        ir_node **phis;
        ir_node *phi, *next;
-       ir_node *head_cp        = get_inversion_copy(loop_head);
-       int arity                       = get_irn_arity(head_cp);
-       int backedges           = get_backedge_n(head_cp, 0);
-       int new_arity           = arity - backedges;
+       ir_node *head_cp = get_inversion_copy(loop_head);
+       ir_graph *irg    = get_irn_irg(head_cp);
+       int arity        = get_irn_arity(head_cp);
+       int backedges    = get_backedge_n(head_cp, 0);
+       int new_arity    = arity - backedges;
        int pos;
        int i;
 
@@ -1265,7 +1074,7 @@ static void fix_copy_inversion(void)
                        ins[pos++] = get_irn_n(head_cp, i);
        }
 
-       new_head = new_Block(new_arity, ins);
+       new_head = new_r_Block(irg, new_arity, ins);
 
        phis = NEW_ARR_F(ir_node *, 0);
 
@@ -1293,44 +1102,9 @@ static void fix_copy_inversion(void)
        DEL_ARR_F(phis);
 }
 
-/**/
-static ir_node *fix_inner_cc_definitions(ir_node *phi, ir_node *pred)
-{
-       int i;
-       ir_node *head_phi;
-       ir_node **head_phi_ins;
-       ir_node *new_loop_head = loop_info.new_loop_head;
-       int new_loop_head_arity = get_irn_arity(new_loop_head);
-       DB((dbg, LEVEL_5, "NEW HEAD %N arity %d\n", new_loop_head, new_loop_head_arity));
-
-       NEW_ARR_A(ir_node *, head_phi_ins, new_loop_head_arity);
-
-       for(i = 0; i < new_loop_head_arity; ++i) {
-               /* Rely on correct backedge info for the new loop head
-                * is set by extend_ins_by_copy. */
-               if(is_nodes_block_marked(get_irn_n(new_loop_head, i))) {
-                       head_phi_ins[i] = pred;
-               } else {
-                       head_phi_ins[i] = get_inversion_copy(pred);
-               }
-               DB((dbg, LEVEL_5, "NEW HEAD %N in %N %N\n", new_loop_head, head_phi_ins[i], current_ir_graph));
-       }
-
-       head_phi= new_r_Phi(new_loop_head,
-                       new_loop_head_arity,
-                       head_phi_ins,
-                       get_irn_mode(phi));
-
-       add_Block_phi(new_loop_head, head_phi);
-
-       DB((dbg, LEVEL_5, "fix inner cc definitions: new head %N has new phi %N from cc phi %N @%N\n",
-                               new_loop_head, head_phi, phi, pred));
-
-       return head_phi;
-}
-
 
-/* Puts the original condition chain at the end of the loop, subsequently to the body.
+/* Puts the original condition chain at the end of the loop,
+ * subsequently to the body.
  * Relies on block phi list and correct backedges.
  */
 static void fix_head_inversion(void)
@@ -1339,9 +1113,10 @@ static void fix_head_inversion(void)
        ir_node **ins;
        ir_node *phi, *next;
        ir_node **phis;
-       int arity                       = get_irn_arity(loop_head);
-       int backedges           = get_backedge_n(loop_head, 0);
-       int new_arity           = backedges;
+       ir_graph *irg = get_irn_irg(loop_head);
+       int arity     = get_irn_arity(loop_head);
+       int backedges = get_backedge_n(loop_head, 0);
+       int new_arity = backedges;
        int pos;
        int i;
 
@@ -1354,37 +1129,39 @@ static void fix_head_inversion(void)
                        ins[pos++] = get_irn_n(loop_head, i);
        }
 
-       new_head = new_Block(new_arity, ins);
+       new_head = new_r_Block(irg, new_arity, ins);
 
        phis = NEW_ARR_F(ir_node *, 0);
 
        for_each_phi(loop_head, phi) {
                ir_node *new_phi;
+               DB((dbg, LEVEL_5, "Fixing phi %N of loop head\n", phi));
 
                NEW_ARR_A(ir_node *, ins, new_arity);
 
                pos = 0;
-               for(i = 0; i < arity; ++i) {
+               for (i = 0; i < arity; ++i) {
                        ir_node *pred = get_irn_n(phi, i);
 
                        if (is_own_backedge(loop_head, i)) {
-                               DB((dbg, LEVEL_5, " !!! PHI not useful %N\n", phi));
-
-                               /* If definition is in the condition chain,
-                                * we need to create a phi in the new loop head */
-                               if (is_nodes_block_marked(pred))
-                                       ins[pos++] = fix_inner_cc_definitions(phi, pred);
-                               else
+                               /* If assignment is in the condition chain,
+                                * we need to create a phi in the new loop head.
+                                * This can only happen for df, not cf. See find_condition_chains. */
+                               /*if (is_nodes_block_marked(pred)) {
                                        ins[pos++] = pred;
+                               } else {*/
+                               ins[pos++] = pred;
+
                        }
                }
+
                new_phi = new_rd_Phi(get_irn_dbg_info(phi),
                        new_head, new_arity, ins,
                        get_irn_mode(phi));
 
                ARR_APP1(ir_node *, phis, new_phi);
 
-               DB((dbg, LEVEL_5, "fix inverted head should exch %N by %N\n", phi, new_phi));
+               DB((dbg, LEVEL_5, "fix inverted head should exch %N by %N (pos %d)\n", phi, new_phi, pos ));
        }
 
        pos = 0;
@@ -1401,9 +1178,9 @@ static void fix_head_inversion(void)
 }
 
 /* Does the loop inversion.  */
-static void inversion_walk(out_edge *head_entries)
+static void inversion_walk(entry_edge *head_entries)
 {
-       int i;
+       size_t i;
 
        /*
         * The order of rewiring bottom-up is crucial.
@@ -1416,7 +1193,7 @@ static void inversion_walk(out_edge *head_entries)
        inc_irg_visited(current_ir_graph);
 
        for (i = 0; i < ARR_LEN(head_entries); ++i) {
-               out_edge entry = head_entries[i];
+               entry_edge entry = head_entries[i];
                ir_node *pred = get_irn_n(entry.node, entry.pos);
 
                DB((dbg, LEVEL_5, "\nInit walk block %N\n", pred));
@@ -1427,9 +1204,9 @@ static void inversion_walk(out_edge *head_entries)
        ir_free_resources(current_ir_graph, IR_RESOURCE_IRN_VISITED);
 
        /* 2. Extends the head control flow successors ins
-        *    by the definitions of the copied head node. */
+        *    with the definitions of the copied head node. */
        for (i = 0; i < ARR_LEN(head_entries); ++i) {
-               out_edge head_out = head_entries[i];
+               entry_edge head_out = head_entries[i];
 
                if (is_Block(head_out.node))
                        extend_ins_by_copy(head_out.node, head_out.pos);
@@ -1438,18 +1215,17 @@ static void inversion_walk(out_edge *head_entries)
        /* 3. construct_ssa for users of definitions in the condition chain,
         *    as there is now a second definition. */
        for (i = 0; i < ARR_LEN(head_entries); ++i) {
-               out_edge head_out = head_entries[i];
+               entry_edge head_out = head_entries[i];
+
                /* Ignore keepalives */
                if (is_End(head_out.node))
                        continue;
 
-               ir_node *is_in_cc = get_nodes_block(get_irn_n(head_out.node, head_out.pos));
-               /* Construct ssa for definitions in the condition chain. */
-               /* TODO Why do we need the check for is_in_cc? All definitions should be there... */
-               if (!is_Block(head_out.node) && is_nodes_block_marked(is_in_cc)) {
+               /* Construct ssa for assignments in the condition chain. */
+               if (!is_Block(head_out.node)) {
                        ir_node *pred, *cppred, *block, *cpblock;
 
-                       pred = get_irn_n(head_out.node, head_out.pos);
+                       pred = head_out.pred;
                        cppred = get_inversion_copy(pred);
                        block = get_nodes_block(pred);
                        cpblock = get_nodes_block(cppred);
@@ -1457,64 +1233,156 @@ static void inversion_walk(out_edge *head_entries)
                }
        }
 
-       /* 4. Remove the ins which are no backedges from the original condition chain,
-        *    as the cc is now subsequently to the body. */
+       /*
+        * If there is an assignment in the condition chain
+        * with a user also in the condition chain,
+        * the dominance frontier is in the new loop head.
+        * The dataflow loop is completely in the condition chain.
+        * Goal:
+        *  To be wired: >|
+        *
+        *  | ,--.   |
+        * Phi_cp |  | copied condition chain
+        * >| |   |  |
+        * >| ?__/   |
+        * >| ,-.
+        *  Phi* |   | new loop head with newly created phi.
+        *   |   |
+        *  Phi  |   | original, inverted condition chain
+        *   |   |   |
+        *   ?__/    |
+        *
+        */
+       for (i = 0; i < ARR_LEN(head_df_loop); ++i) {
+               entry_edge head_out = head_df_loop[i];
+
+               /* Construct ssa for assignments in the condition chain. */
+               ir_node *pred, *cppred, *block, *cpblock;
+
+               pred = head_out.pred;
+               cppred = get_inversion_copy(pred);
+               assert(cppred && pred);
+               block = get_nodes_block(pred);
+               cpblock = get_nodes_block(cppred);
+               construct_ssa(block, pred, cpblock, cppred);
+       }
+
+       /* 4. Remove the ins which are no backedges from the original condition chain
+        *    as the cc is now subsequent to the body. */
        fix_head_inversion();
 
        /* 5. Remove the backedges of the copied condition chain,
-        *    because it is going to be the new 'head' in advance to the loop */
+        *    because it is going to be the new 'head' in advance to the loop. */
        fix_copy_inversion();
+
 }
 
-/* Analyse loop, if inversion is possible or reasonable. Then do the inversion. */
+/* Performs loop inversion of cur_loop if possible and reasonable. */
 static void loop_inversion(void)
 {
+       int      loop_depth;
+       unsigned max_loop_nodes = opt_params.max_loop_size;
+       unsigned max_loop_nodes_adapted;
+       int      depth_adaption = opt_params.depth_adaption;
+
        unsigned do_inversion = 1;
+       unsigned has_cc = 0;
+
+       /* Depth of 0 is the procedure and 1 a topmost loop. */
+       loop_depth = get_loop_depth(cur_loop) - 1;
+
+       /* Calculating in per mil. */
+       max_loop_nodes_adapted = get_max_nodes_adapted(loop_depth);
+
+       DB((dbg, LEVEL_1, "max_nodes: %d\nmax_nodes_adapted %d at depth of %d (adaption %d)\n",
+                       max_loop_nodes, max_loop_nodes_adapted, loop_depth, depth_adaption));
+
+       if (! (loop_info.nodes > 0))
+               return;
+
+#if LOOP_IGNORE_NODE_LIMITS
+       DB((dbg, LEVEL_1, "WARNING: Loop node limitations ignored."));
+#else
+       if (loop_info.nodes > max_loop_nodes) {
+               /* Only for stats */
+               DB((dbg, LEVEL_1, "Nodes %d > allowed nodes %d\n",
+                       loop_info.nodes, loop_depth, max_loop_nodes));
+               count_stats(stats.too_large);
+               /* no RETURN */
+               /* Adaption might change it */
+       }
+
+       /* Limit processing to loops smaller than given parameter. */
+       if (loop_info.nodes > max_loop_nodes_adapted) {
+               DB((dbg, LEVEL_1, "Nodes %d > allowed nodes (depth %d adapted) %d\n",
+                       loop_info.nodes, loop_depth, max_loop_nodes_adapted));
+               count_stats(stats.too_large_adapted);
+               return;
+       }
+
+       if (loop_info.calls > opt_params.allowed_calls) {
+               DB((dbg, LEVEL_1, "Calls %d > allowed calls %d\n",
+                       loop_info.calls, opt_params.allowed_calls));
+               count_stats(stats.calls_limit);
+               return;
+       }
+#endif
 
-       inversion_head_node_limit = INT_MAX;
+       /*inversion_head_node_limit = INT_MAX;*/
        ir_reserve_resources(current_ir_graph, IR_RESOURCE_BLOCK_MARK);
 
        /* Reset block marks.
         * We use block marks to flag blocks of the original condition chain. */
        irg_walk_graph(current_ir_graph, reset_block_mark, NULL, NULL);
 
-       loop_info.blocks = get_loop_n_blocks(cur_loop);
-       cond_chain_entries = NEW_ARR_F(out_edge, 0);
-
-       head_inversion_node_count = 0;
-       head_inversion_block_count = 0;
+       /*loop_info.blocks = get_loop_n_blocks(cur_loop);*/
+       cond_chain_entries = NEW_ARR_F(entry_edge, 0);
+       head_df_loop = NEW_ARR_F(entry_edge, 0);
 
-       set_Block_mark(loop_head, 1);
-       mark_irn_visited(loop_head);
+       /*head_inversion_node_count = 0;*/
+       inversion_blocks_in_cc = 0;
 
        /* Use phase to keep copy of nodes from the condition chain. */
        phase = new_phase(current_ir_graph, phase_irn_init_default);
 
+       /* Search for condition chains and temporarily save the blocks in an array. */
+       cc_blocks = NEW_ARR_F(ir_node *, 0);
        inc_irg_visited(current_ir_graph);
+       has_cc = find_condition_chain(loop_head);
 
-       /* Search for condition chains. */
-       find_condition_chains(loop_head);
+       unmark_not_allowed_cc_blocks();
+       DEL_ARR_F(cc_blocks);
 
-       DB((dbg, LEVEL_3, "Loop contains %d blocks.\n", loop_info.blocks));
+#if LOOP_IGNORE_NODE_LIMITS
+       (void) unmark_cc_blocks;
+#else
+       /* Condition chain too large.
+        * Loop should better be small enough to fit into the cache. */
+       /* TODO Of course, we should take a small enough cc in the first place,
+        * which is not that simple. (bin packing)  */
+       if (loop_info.cc_size > opt_params.max_cc_size) {
+               count_stats(stats.cc_limit_reached);
 
-       if (loop_info.blocks < 2) {
                do_inversion = 0;
-               DB((dbg, LEVEL_3,
-                       "Loop contains %d (less than 2) blocks => No Inversion done.\n",
-                       loop_info.blocks));
+
+               /* Unmark cc blocks except the head.
+                * Invert head only for possible unrolling. */
+               unmark_cc_blocks();
+
        }
+#endif
 
        /* We also catch endless loops here,
         * because they do not have a condition chain. */
-       if (head_inversion_block_count < 1) {
+       if (inversion_blocks_in_cc < 1) {
                do_inversion = 0;
                DB((dbg, LEVEL_3,
                        "Loop contains %d (less than 1) invertible blocks => No Inversion done.\n",
-                       head_inversion_block_count));
+                       inversion_blocks_in_cc));
        }
 
        if (do_inversion) {
-               cur_head_outs = NEW_ARR_F(out_edge, 0);
+               cur_head_outs = NEW_ARR_F(entry_edge, 0);
 
                /* Get all edges pointing into the condition chain. */
                irg_walk_graph(current_ir_graph, get_head_outs, NULL, NULL);
@@ -1523,425 +1391,1353 @@ static void loop_inversion(void)
                inversion_walk(cur_head_outs);
 
                DEL_ARR_F(cur_head_outs);
+
                /* Duplicated blocks changed doms */
                set_irg_doms_inconsistent(current_ir_graph);
                /* Loop content changed */
                set_irg_loopinfo_inconsistent(current_ir_graph);
-               /* TODO are they? */
+               /* TODO are they? Depends on set_irn_in and set_irn_n exchange and new_node. */
                set_irg_outs_inconsistent(current_ir_graph);
+
+               count_stats(stats.inverted);
        }
 
        /* free */
        phase_free(phase);
        DEL_ARR_F(cond_chain_entries);
+       DEL_ARR_F(head_df_loop);
+
        ir_free_resources(current_ir_graph, IR_RESOURCE_BLOCK_MARK);
 }
 
-/**
- * Rewire floating copies of the current loop.
- */
-static void place_copies(int copies)
+/* Fix the original loop_heads ins for invariant unrolling case. */
+static void unrolling_fix_loop_head_inv(void)
 {
-       ir_node *loophead = loop_head;
-       int headarity =         get_irn_arity(loophead);
+       ir_node *ins[2];
        ir_node *phi;
-       int i, pos, c;
-
-       pos = 0;
-       /* Append the copies to the existing loop. */
-       for (i = 0; i < headarity; ++i) {
-               /* Build unrolled loop top down */
-               if (is_backedge(loophead, i) && !is_alien_edge(loophead, i)) {
-                       for (c = 0; c < copies; ++c) {
-                               ir_node *upper_head;
-                               ir_node *lower_head = get_copy(loophead, c);
-                               ir_node *upper_pred;
-
-                               if (c == 0) {
-                                       upper_head = loophead;
-                                       upper_pred = get_irn_n(loophead, i);
-                               } else {
-                                       upper_head = get_copy(loophead, c - 1);
-                                       upper_pred = get_copy_safe(get_irn_n(loophead, i), c - 1);
-                               }
-                               set_irn_n(lower_head, pos, upper_pred);
-                               for_each_phi(loophead, phi) {
-                                       ir_node *lower_phi, *upper_phi, *upper_pred_phi;
-                                       lower_phi = get_copy(phi, c);
-                                       if (c == 0) {
-                                               upper_phi = phi;
-                                               upper_pred_phi = get_irn_n(phi, i);
-                                       } else {
-                                               upper_phi = get_copy(phi, c - 1);
-                                               upper_pred_phi = get_copy_safe(get_irn_n(phi, i), c - 1);
-                                       }
-
-                                       DB((dbg, LEVEL_5, "Rewire %N @%d to %N\n",
-                                                               lower_phi, pos, upper_pred_phi));
+       ir_node *proj = new_Proj(loop_info.duff_cond, mode_X, 0);
+       ir_node *head_pred = get_irn_n(loop_head, loop_info.be_src_pos);
+       ir_node *loop_condition = get_unroll_copy(head_pred, unroll_nr - 1);
 
-                                       /* Relying on phi nodes with 1 in to be present. */
-                                       assert(is_Phi(lower_phi));
+       /* Original loop_heads ins are:
+        * duff block and the own backedge */
 
-/* Do not fix phis here. Chained phis will cause a defective copy array. */
-#if 0
-                                       if (get_irn_arity(lower_phi) == 1) {
-                                               ir_node *single_in[1];
-                                               ir_node *cp;
-                                               single_in[0] = upper_pred_phi;
+       ins[0] = loop_condition;
+       ins[1] = proj;
+       set_irn_in(loop_head, 2, ins);
+       DB((dbg, LEVEL_4, "Rewire ins of block loophead %N to pred %N and duffs entry %N \n" , loop_head, ins[0], ins[1]));
 
-                                               cp = new_rd_Phi(get_irn_dbg_info(lower_phi),
-                                                               get_nodes_block(lower_phi), 1, single_in,
-                                                               get_irn_mode(lower_phi));
+       for_each_phi(loop_head, phi) {
+               ir_node *pred = get_irn_n(phi, loop_info.be_src_pos);
+               /* TODO we think it is a phi, but for Mergesort it is not the case.*/
 
-                                               set_copy(phi, c, cp);
-                                               exchange(lower_phi, cp);
-                                       } else
-#endif
-                                               set_irn_n(lower_phi, pos, upper_pred_phi);
+               ir_node *last_pred = get_unroll_copy(pred, unroll_nr - 1);
 
-                               }
-                       }
-                       ++pos;
-                       /* Fix the topmost loop heads backedges. */
-                       set_irn_n(loophead, i, get_copy(get_irn_n(loophead, i), copies - 1));
-                       for_each_phi(loophead, phi) {
-                               ir_node *last_cp = get_copy_safe(get_irn_n(phi, i), copies - 1);
-                               set_irn_n(phi, i, last_cp);
-                       }
-               }
+               ins[0] = last_pred;
+               ins[1] = (ir_node*)get_irn_link(phi);
+               set_irn_in(phi, 2, ins);
+               DB((dbg, LEVEL_4, "Rewire ins of loophead phi %N to pred %N and duffs entry %N \n" , phi, ins[0], ins[1]));
        }
 }
 
-/* Copies the cur_loop */
-static void copy_loop(out_edge *cur_loop_outs, int copies)
+/* Removes previously created phis with only 1 in. */
+static void correct_phis(ir_node *node, void *env)
 {
-       int i, c;
-       unroll_arity = get_backedge_n(loop_head, 0);
-
-       ir_reserve_resources(current_ir_graph, IR_RESOURCE_IRN_VISITED);
+       (void)env;
 
-       /* copy loop */
-       for (c = 0; c < copies; ++c) {
+       if (is_Phi(node) && get_irn_arity(node) == 1) {
+               ir_node *exch;
+               ir_node *in[1];
 
-               inc_irg_visited(current_ir_graph);
+               in[0] = get_irn_n(node, 0);
 
-               DB((dbg, LEVEL_5, "          ### Copy_loop  copy n: %d ###\n", c));
-               for (i = 0; i < ARR_LEN(cur_loop_outs); ++i) {
-                       out_edge entry = cur_loop_outs[i];
-                       ir_node *pred = get_irn_n(entry.node, entry.pos);
+               exch = new_rd_Phi(get_irn_dbg_info(node),
+                   get_nodes_block(node), 1, in,
+                       get_irn_mode(node));
 
-                       copy_walk_n(pred, is_in_loop, c, c ? 0 : copies);
-               }
+               exchange(node, exch);
        }
-
-       ir_free_resources(current_ir_graph, IR_RESOURCE_IRN_VISITED);
 }
 
-/**/
-static void create_duffs_device(int unroll_number)
+/* Unrolling: Rewire floating copies. */
+static void place_copies(int copies)
 {
-       (void)unroll_number;
-}
+       ir_node *loophead = loop_head;
+       size_t i;
+       int c;
+       int be_src_pos = loop_info.be_src_pos;
 
-#if 1
+       /* Serialize loops by fixing their head ins.
+        * Processed are the copies.
+        * The original loop is done after that, to keep backedge infos. */
+       for (c = 0; c < copies; ++c) {
+               ir_node *upper = get_unroll_copy(loophead, c);
+               ir_node *lower = get_unroll_copy(loophead, c + 1);
+               ir_node *phi;
+               ir_node *topmost_be_block = get_nodes_block(get_irn_n(loophead, be_src_pos));
 
-static unsigned is_loop_invariant_val(ir_node *node)
+               /* Important: get the preds first and then their copy. */
+               ir_node *upper_be_block = get_unroll_copy(topmost_be_block, c);
+               ir_node *new_jmp = new_r_Jmp(upper_be_block);
+               DB((dbg, LEVEL_5, " place_copies upper %N lower %N\n", upper, lower));
+
+               DB((dbg, LEVEL_5, "topmost be block %N \n", topmost_be_block));
+
+               if (loop_info.unroll_kind == constant) {
+                       ir_node *ins[1];
+                       ins[0] = new_jmp;
+                       set_irn_in(lower, 1, ins);
+
+                       for_each_phi(loophead, phi) {
+                               ir_node *topmost_def = get_irn_n(phi, be_src_pos);
+                               ir_node *upper_def = get_unroll_copy(topmost_def, c);
+                               ir_node *lower_phi = get_unroll_copy(phi, c + 1);
+
+                               /* It is possible, that the value used
+                                * in the OWN backedge path is NOT defined in this loop. */
+                               if (is_in_loop(topmost_def))
+                                       ins[0] = upper_def;
+                               else
+                                       ins[0] = topmost_def;
+
+                               set_irn_in(lower_phi, 1, ins);
+                               /* Need to replace phis with 1 in later. */
+                       }
+               } else {
+                       /* Invariant case */
+                       /* Every node has 2 ins. One from the duff blocks
+                        * and one from the previously unrolled loop. */
+                       ir_node *ins[2];
+                       /* Calculate corresponding projection of mod result for this copy c */
+                       ir_node *proj = new_Proj(loop_info.duff_cond, mode_X, unroll_nr - c - 1);
+                       DB((dbg, LEVEL_4, "New duff proj %N\n" , proj));
+
+                       ins[0] = new_jmp;
+                       ins[1] = proj;
+                       set_irn_in(lower, 2, ins);
+                       DB((dbg, LEVEL_4, "Rewire ins of Block %N to pred %N and duffs entry %N \n" , lower, ins[0], ins[1]));
+
+                       for_each_phi(loophead, phi) {
+                               ir_node *topmost_phi_pred = get_irn_n(phi, be_src_pos);
+                               ir_node *upper_phi_pred;
+                               ir_node *lower_phi;
+                               ir_node *duff_phi;
+
+                               lower_phi = get_unroll_copy(phi, c + 1);
+                               duff_phi = (ir_node*)get_irn_link(phi);
+                               DB((dbg, LEVEL_4, "DD Link of %N is %N\n" , phi, duff_phi));
+
+                               /*  */
+                               if (is_in_loop(topmost_phi_pred)) {
+                                       upper_phi_pred = get_unroll_copy(topmost_phi_pred, c);
+                               } else {
+                                       upper_phi_pred = topmost_phi_pred;
+                               }
+
+                               ins[0] = upper_phi_pred;
+                               ins[1] = duff_phi;
+                               set_irn_in(lower_phi, 2, ins);
+                               DB((dbg, LEVEL_4, "Rewire ins of %N to pred %N and duffs entry %N \n" , lower_phi, ins[0], ins[1]));
+                       }
+               }
+       }
+
+       /* Reconnect last copy. */
+       for (i = 0; i < ARR_LEN(loop_entries); ++i) {
+               entry_edge edge = loop_entries[i];
+               /* Last copy is at the bottom */
+               ir_node *new_pred = get_unroll_copy(edge.pred, copies);
+               set_irn_n(edge.node, edge.pos, new_pred);
+       }
+
+       /* Fix original loops head.
+        * Done in the end, as ins and be info were needed before. */
+       if (loop_info.unroll_kind == constant) {
+               ir_node *phi;
+               ir_node *head_pred = get_irn_n(loop_head, be_src_pos);
+               ir_node *loop_condition = get_unroll_copy(head_pred, unroll_nr - 1);
+
+               set_irn_n(loop_head, loop_info.be_src_pos, loop_condition);
+
+               for_each_phi(loop_head, phi) {
+                       ir_node *pred = get_irn_n(phi, be_src_pos);
+                       ir_node *last_pred;
+
+                       /* It is possible, that the value used
+                        * in the OWN backedge path is NOT assigned in this loop. */
+                       if (is_in_loop(pred))
+                               last_pred = get_unroll_copy(pred, copies);
+                       else
+                               last_pred = pred;
+                       set_irn_n(phi, be_src_pos, last_pred);
+               }
+
+       } else {
+               unrolling_fix_loop_head_inv();
+       }
+}
+
+/* Copies the cur_loop several times. */
+static void copy_loop(entry_edge *cur_loop_outs, int copies)
+{
+       int c;
+
+       ir_reserve_resources(current_ir_graph, IR_RESOURCE_IRN_VISITED);
+
+       for (c = 0; c < copies; ++c) {
+               size_t i;
+
+               inc_irg_visited(current_ir_graph);
+
+               DB((dbg, LEVEL_5, "         ### Copy_loop  copy nr: %d ###\n", c));
+               for (i = 0; i < ARR_LEN(cur_loop_outs); ++i) {
+                       entry_edge entry = cur_loop_outs[i];
+                       ir_node *pred = get_irn_n(entry.node, entry.pos);
+
+                       copy_walk_n(pred, is_in_loop, c + 1);
+               }
+       }
+
+       ir_free_resources(current_ir_graph, IR_RESOURCE_IRN_VISITED);
+}
+
+
+/* Creates a new phi from the given phi node omitting own bes,
+ * using be_block as supplier of backedge informations. */
+static ir_node *clone_phis_sans_bes(ir_node *phi, ir_node *be_block, ir_node *dest_block)
+{
+       ir_node **ins;
+       int arity = get_irn_arity(phi);
+       int i, c = 0;
+       ir_node *newphi;
+
+       assert(get_irn_arity(phi) == get_irn_arity(be_block));
+       assert(is_Phi(phi));
+
+       ins = NEW_ARR_F(ir_node *, arity);
+       for (i = 0; i < arity; ++i) {
+               if (! is_own_backedge(be_block, i)) {
+                       ins[c] = get_irn_n(phi, i);
+                       ++c;
+               }
+       }
+
+       newphi = new_r_Phi(dest_block, c, ins, get_irn_mode(phi));
+
+       set_irn_link(phi, newphi);
+       DB((dbg, LEVEL_4, "Linking for duffs device %N to %N\n", phi, newphi));
+
+       return newphi;
+}
+
+/* Creates a new block from the given block node omitting own bes,
+ * using be_block as supplier of backedge informations. */
+static ir_node *clone_block_sans_bes(ir_node *node, ir_node *be_block)
+{
+       ir_node **ins;
+       int arity = get_irn_arity(node);
+       int i, c = 0;
+
+       assert(get_irn_arity(node) == get_irn_arity(be_block));
+       assert(is_Block(node));
+
+       NEW_ARR_A(ir_node *, ins, arity);
+       for (i = 0; i < arity; ++i) {
+               if (! is_own_backedge(be_block, i)) {
+                       ins[c] = get_irn_n(node, i);
+                       ++c;
+               }
+       }
+
+       return new_Block(c, ins);
+}
+
+/* Creates a structure to calculate absolute value of node op.
+ * Returns mux node with absolute value. */
+static ir_node *new_Abs(ir_node *op, ir_mode *mode)
+{
+  ir_graph *irg      = get_irn_irg(op);
+  ir_node  *block    = get_nodes_block(op);
+  ir_node  *zero     = new_r_Const(irg, get_mode_null(mode));
+  ir_node  *cmp      = new_r_Cmp(block, op, zero, ir_relation_less);
+  ir_node  *minus_op = new_r_Minus(block, op, mode);
+  ir_node  *mux      = new_r_Mux(block, cmp, op, minus_op, mode);
+
+  return mux;
+}
+
+
+/* Creates blocks for duffs device, using previously obtained
+ * informations about the iv.
+ * TODO split */
+static void create_duffs_block(void)
+{
+       ir_mode *mode;
+
+       ir_node *block1, *count_block, *duff_block;
+       ir_node *ems, *ems_mod, *ems_div, *ems_mod_proj, *cmp_null,
+               *ems_mode_cond, *x_true, *x_false, *const_null;
+       ir_node *true_val, *false_val;
+       ir_node *ins[2];
+
+       ir_node *duff_mod, *proj, *cond;
+
+       ir_node *count, *correction, *unroll_c;
+       ir_node *cmp_bad_count, *good_count, *bad_count, *count_phi, *bad_count_neg;
+       ir_node *phi;
+
+       mode = get_irn_mode(loop_info.end_val);
+       const_null = new_Const(get_mode_null(mode));
+
+       /* TODO naming
+        * 1. Calculate first approach to count.
+        *    Condition: (end - start) % step == 0 */
+       block1 = clone_block_sans_bes(loop_head, loop_head);
+       DB((dbg, LEVEL_4, "Duff block 1 %N\n", block1));
+
+       /* Create loop entry phis in first duff block
+        * as it becomes the loops preheader */
+       for_each_phi(loop_head, phi) {
+               /* Returns phis pred if phi would have arity 1*/
+               ir_node *new_phi = clone_phis_sans_bes(phi, loop_head, block1);
+
+               DB((dbg, LEVEL_4, "HEAD %N phi %N\n", loop_head, phi));
+               DB((dbg, LEVEL_4, "BLOCK1 %N phi %N\n", block1, new_phi));
+       }
+
+       ems = new_r_Sub(block1, loop_info.end_val, loop_info.start_val,
+               get_irn_mode(loop_info.end_val));
+               DB((dbg, LEVEL_4, "BLOCK1 sub %N\n", ems));
+
+
+       ems = new_Sub(loop_info.end_val, loop_info.start_val,
+               get_irn_mode(loop_info.end_val));
+
+       DB((dbg, LEVEL_4, "mod ins %N %N\n", ems, loop_info.step));
+       ems_mod = new_r_Mod(block1,
+               new_NoMem(),
+               ems,
+               loop_info.step,
+               mode,
+               op_pin_state_pinned);
+       ems_div = new_r_Div(block1,
+               new_NoMem(),
+               ems,
+               loop_info.step,
+               mode,
+               op_pin_state_pinned);
+
+       DB((dbg, LEVEL_4, "New module node %N\n", ems_mod));
+
+       ems_mod_proj = new_r_Proj(ems_mod, mode_Iu, pn_Mod_res);
+       cmp_null = new_r_Cmp(block1, ems_mod_proj, const_null, ir_relation_less);
+       ems_mode_cond = new_r_Cond(block1, cmp_null);
+
+       /* ems % step == 0 */
+       x_true = new_r_Proj(ems_mode_cond, mode_X, pn_Cond_true);
+       /* ems % step != 0 */
+       x_false = new_r_Proj(ems_mode_cond, mode_X, pn_Cond_false);
+
+       /* 2. Second block.
+        * Assures, duffs device receives a valid count.
+        * Condition:
+        *     decreasing: count < 0
+        *     increasing: count > 0
+        */
+       ins[0] = x_true;
+       ins[1] = x_false;
+
+       count_block = new_Block(2, ins);
+       DB((dbg, LEVEL_4, "Duff block 2 %N\n", count_block));
+
+
+       /* Increase loop-taken-count depending on the loop condition
+        * uses the latest iv to compare to. */
+       if (loop_info.latest_value == 1) {
+               /* ems % step == 0 :  +0 */
+               true_val = new_Const(get_mode_null(mode));
+               /* ems % step != 0 :  +1 */
+               false_val = new_Const(get_mode_one(mode));
+       } else {
+               ir_tarval *tv_two = new_tarval_from_long(2, mode);
+               /* ems % step == 0 :  +1 */
+               true_val = new_Const(get_mode_one(mode));
+               /* ems % step != 0 :  +2 */
+               false_val = new_Const(tv_two);
+       }
+
+       ins[0] = true_val;
+       ins[1] = false_val;
+
+       correction = new_r_Phi(count_block, 2, ins, mode);
+
+       count = new_r_Proj(ems_div, mode, pn_Div_res);
+
+       /* (end - start) / step  +  correction */
+       count = new_Add(count, correction, mode);
+
+       /* We preconditioned the loop to be tail-controlled.
+        * So, if count is something 'wrong' like 0,
+        * negative/positive (depending on step direction),
+        * we may take the loop once (tail-contr.) and leave it
+        * to the existing condition, to break; */
+
+       /* Depending on step direction, we have to check for > or < 0 */
+       if (loop_info.decreasing == 1) {
+               cmp_bad_count = new_r_Cmp(count_block, count, const_null,
+                                         ir_relation_less);
+       } else {
+               cmp_bad_count = new_r_Cmp(count_block, count, const_null,
+                                         ir_relation_greater);
+       }
+
+       bad_count_neg = new_r_Cond(count_block, cmp_bad_count);
+       good_count = new_Proj(bad_count_neg, mode_X, pn_Cond_true);
+       bad_count = new_Proj(ems_mode_cond, mode_X, pn_Cond_false);
+
+       /* 3. Duff Block
+        *    Contains module to decide which loop to start from. */
+
+       ins[0] = good_count;
+       ins[1] = bad_count;
+       duff_block = new_Block(2, ins);
+       DB((dbg, LEVEL_4, "Duff block 3 %N\n", duff_block));
+
+       /* Get absolute value */
+       ins[0] = new_Abs(count, mode);
+       /* Manually feed the aforementioned count = 1 (bad case)*/
+       ins[1] = new_Const(get_mode_one(mode));
+       count_phi = new_r_Phi(duff_block, 2, ins, mode);
+
+       unroll_c = new_Const(new_tarval_from_long((long)unroll_nr, mode));
+
+       /* count % unroll_nr */
+       duff_mod = new_r_Mod(duff_block,
+               new_NoMem(),
+               count_phi,
+               unroll_c,
+               mode,
+               op_pin_state_pinned);
+
+
+       proj = new_Proj(duff_mod, mode, pn_Mod_res);
+       /* condition does NOT create itself in the block of the proj! */
+       cond = new_r_Cond(duff_block, proj);
+
+       loop_info.duff_cond = cond;
+}
+
+/* Returns 1 if given node is not in loop,
+ * or if it is a phi of the loop head with only loop invariant defs.
+ */
+static unsigned is_loop_invariant_def(ir_node *node)
 {
        int i;
 
-       if (! is_in_loop(node))
+       if (! is_in_loop(node)) {
+               DB((dbg, LEVEL_4, "Not in loop %N\n", node));
+               /* || is_Const(node) || is_SymConst(node)) {*/
                return 1;
+       }
 
-       /* TODO all cases? and how to use the dom tree for that. */
-
+       /* If this is a phi of the loophead shared by more than 1 loop,
+        * we need to check if all defs are not in the loop.  */
        if (is_Phi(node)) {
+               ir_node *block;
+               block = get_nodes_block(node);
+
+               /* To prevent unexpected situations. */
+               if (block != loop_head) {
+                       return 0;
+               }
+
                for (i = 0; i < get_irn_arity(node); ++i) {
-                       if (is_own_backedge(get_nodes_block(node), i) && get_irn_n(node, i) != node)
+                       /* Check if all bes are just loopbacks. */
+                       if (is_own_backedge(block, i) && get_irn_n(node, i) != node)
                                return 0;
                }
+               DB((dbg, LEVEL_4, "invar %N\n", node));
+               return 1;
        }
-       return 1;
+       DB((dbg, LEVEL_4, "Not invar %N\n", node));
+
+       return 0;
 }
 
-/* TODO name */
-static ir_node *is_loop_iteration(ir_node *node)
+/* Returns 1 if one pred of node is invariant and the other is not.
+ * invar_pred and other are set analogously. */
+static unsigned get_invariant_pred(ir_node *node, ir_node **invar_pred, ir_node **other)
+{
+       ir_node *pred0 = get_irn_n(node, 0);
+       ir_node *pred1 = get_irn_n(node, 1);
+
+       *invar_pred = NULL;
+       *other = NULL;
+
+       if (is_loop_invariant_def(pred0)) {
+               DB((dbg, LEVEL_4, "pred0 invar %N\n", pred0));
+               *invar_pred = pred0;
+               *other = pred1;
+       }
+
+       if (is_loop_invariant_def(pred1)) {
+               DB((dbg, LEVEL_4, "pred1 invar %N\n", pred1));
+
+               if (*invar_pred != NULL) {
+                       /* RETURN. We do not want both preds to be invariant. */
+                       return 0;
+               }
+
+               *other = pred0;
+               *invar_pred = pred1;
+               return 1;
+       } else {
+               DB((dbg, LEVEL_4, "pred1 not invar %N\n", pred1));
+
+               if (*invar_pred != NULL)
+                       return 1;
+               else
+                       return 0;
+       }
+}
+
+/* Starts from a phi that may belong to an iv.
+ * If an add forms a loop with iteration_phi,
+ * and add uses a constant, 1 is returned
+ * and 'start' as well as 'add' are sane. */
+static unsigned get_start_and_add(ir_node *iteration_phi, unrolling_kind_flag role)
 {
        int i;
-       ir_node *found_add = NULL;
+       ir_node *found_add = loop_info.add;
+       int arity = get_irn_arity(iteration_phi);
 
-       if (!is_in_loop(node))
-               return NULL;
+       DB((dbg, LEVEL_4, "Find start and add from %N\n", iteration_phi));
 
-       if (is_Add(node))
-               return node;
+       for (i = 0; i < arity; ++i) {
 
-       /*TODO all cases? and how do i use the dom tree for that.*/
+               /* Find start_val which needs to be pred of the iteration_phi.
+                * If start_val already known, sanity check. */
+               if (!is_backedge(get_nodes_block(loop_info.iteration_phi), i)) {
+                       ir_node *found_start_val = get_irn_n(loop_info.iteration_phi, i);
 
-       if (is_Phi(node)) {
-               for (i = 0; i < get_irn_arity(node); ++i) {
-                       ir_node *new_found;
-                       if (! is_own_backedge(get_nodes_block(node), i))
-                               continue;
-                       new_found = get_irn_n(node,i);
+                       DB((dbg, LEVEL_4, "found_start_val %N\n", found_start_val));
 
-                       if (found_add && found_add != new_found)
-                               return NULL;
+                       /* We already found a start_val it has to be always the same. */
+                       if (loop_info.start_val && found_start_val != loop_info.start_val)
+                               return 0;
 
-                       found_add = new_found;
+                       if ((role == constant) && !(is_SymConst(found_start_val) || is_Const(found_start_val)))
+                                       return 0;
+                       else if((role == constant) && !(is_loop_invariant_def(found_start_val)))
+                                       return 0;
+
+                       loop_info.start_val = found_start_val;
+               }
+
+               /* The phi has to be in the loop head.
+                * Follow all own backedges. Every value supplied from these preds of the phi
+                * needs to origin from the same add. */
+               if (is_own_backedge(get_nodes_block(loop_info.iteration_phi), i)) {
+                       ir_node *new_found = get_irn_n(loop_info.iteration_phi,i);
+
+                       DB((dbg, LEVEL_4, "is add? %N\n", new_found));
+
+                       if (! (is_Add(new_found) || is_Sub(new_found)) || (found_add && found_add != new_found))
+                               return 0;
+                       else
+                               found_add = new_found;
                }
        }
-       return found_add;
+
+       loop_info.add = found_add;
+
+       return 1;
 }
 
-/* counting loop */
-static unsigned get_unroll_decision(out_edge *cur_loop_outs)
+
+/* Returns 1 if one pred of node is a const value and the other is not.
+ * const_pred and other are set analogously. */
+static unsigned get_const_pred(ir_node *node, ir_node **const_pred, ir_node **other)
 {
-       int i;
-       ir_node *pred0, *pred1, *projx, *cond, *projres, *loop_condition;
-       ir_node *iteration, *add, *iteration_phi, *end_val, *step, *add_in0, *add_in1;
+       ir_node *pred0 = get_irn_n(node, 0);
+       ir_node *pred1 = get_irn_n(node, 1);
 
-       (void) cur_loop_outs;
-       (void) i;
+       DB((dbg, LEVEL_4, "Checking for constant pred of %N\n", node));
 
+       *const_pred = NULL;
+       *other = NULL;
 
-       /* There is more than 1 condition for the loop exit. We cannot cope this with duffs device. */
-       if (loop_info.cf_outs != 1)
+       /*DB((dbg, LEVEL_4, "is %N const\n", pred0));*/
+       if (is_Const(pred0) || is_SymConst(pred0)) {
+               *const_pred = pred0;
+               *other = pred1;
+       }
+
+       /*DB((dbg, LEVEL_4, "is %N const\n", pred1));*/
+       if (is_Const(pred1) || is_SymConst(pred1)) {
+               if (*const_pred != NULL) {
+                       /* RETURN. We do not want both preds to be constant. */
+                       return 0;
+               }
+
+               *other = pred0;
+               *const_pred = pred1;
+       }
+
+       if (*const_pred == NULL)
                return 0;
+       else
+               return 1;
+}
+
+/* Returns 1 if loop exits within 2 steps of the iv.
+ * Norm_proj means we do not exit the loop.*/
+static unsigned simulate_next(ir_tarval **count_tar,
+               ir_tarval *stepped, ir_tarval *step_tar, ir_tarval *end_tar,
+               ir_relation norm_proj)
+{
+       ir_tarval *next;
 
-       /*TODO test for impact on performance */
-       if (loop_info.calls > 0)
+       DB((dbg, LEVEL_4, "Loop taken if (stepped)%ld %s (end)%ld ",
+                               get_tarval_long(stepped),
+                               get_relation_string((norm_proj)),
+                               get_tarval_long(end_tar)));
+       DB((dbg, LEVEL_4, "comparing latest value %d\n", loop_info.latest_value));
+
+       /* If current iv does not stay in the loop,
+        * this run satisfied the exit condition. */
+       if (! (tarval_cmp(stepped, end_tar) & norm_proj))
+               return 1;
+
+       DB((dbg, LEVEL_4, "Result: (stepped)%ld IS %s (end)%ld\n",
+                               get_tarval_long(stepped),
+                               get_relation_string(tarval_cmp(stepped, end_tar)),
+                               get_tarval_long(end_tar)));
+
+       /* next step */
+       if (is_Add(loop_info.add))
+               next = tarval_add(stepped, step_tar);
+       else
+               /* sub */
+               next = tarval_sub(stepped, step_tar, get_irn_mode(loop_info.end_val));
+
+       DB((dbg, LEVEL_4, "Loop taken if %ld %s %ld ",
+                               get_tarval_long(next),
+                               get_relation_string(norm_proj),
+                               get_tarval_long(end_tar)));
+       DB((dbg, LEVEL_4, "comparing latest value %d\n", loop_info.latest_value));
+
+       /* Increase steps. */
+       *count_tar = tarval_add(*count_tar, get_tarval_one(get_tarval_mode(*count_tar)));
+
+       /* Next has to fail the loop condition, or we will never exit. */
+       if (! (tarval_cmp(next, end_tar) & norm_proj))
+               return 1;
+       else
                return 0;
+}
 
+/* Check if loop meets requirements for a 'simple loop':
+ * - Exactly one cf out
+ * - Allowed calls
+ * - Max nodes after unrolling
+ * - tail-controlled
+ * - exactly one be
+ * - cmp
+ * Returns Projection of cmp node or NULL; */
+static ir_node *is_simple_loop(void)
+{
+       int arity, i;
+       ir_node *loop_block, *exit_block, *projx, *cond, *cmp;
 
-       projx = get_irn_n(loop_info.cf_out.node, loop_info.cf_out.pos);
+       /* Maximum of one condition, and no endless loops. */
+       if (loop_info.cf_outs != 1)
+               return NULL;
+
+       DB((dbg, LEVEL_4, "1 loop exit\n"));
+
+#if LOOP_IGNORE_NODE_LIMITS
+       /* Ignore loop size. Probably not wise in other than testcases. */
+       loop_info.max_unroll = 40;
+#else
+       /* Calculate maximum unroll_nr keeping node count below limit. */
+       loop_info.max_unroll = (int)((double)opt_params.max_unrolled_loop_size / (double)loop_info.nodes);
+       if (loop_info.max_unroll < 2) {
+               count_stats(stats.too_large);
+               return NULL;
+       }
+#endif
+
+
+       DB((dbg, LEVEL_4, "maximum unroll factor %u, to not exceed node limit \n",
+               opt_params.max_unrolled_loop_size));
+
+       arity = get_irn_arity(loop_head);
+       /* RETURN if we have more than 1 be. */
+       /* Get my backedges without alien bes. */
+       loop_block = NULL;
+       for (i = 0; i < arity; ++i) {
+               ir_node *pred = get_irn_n(loop_head, i);
+               if (is_own_backedge(loop_head, i)) {
+                       if (loop_block)
+                               /* Our simple loops may have only one backedge. */
+                               return NULL;
+                       else {
+                               loop_block = get_nodes_block(pred);
+                               loop_info.be_src_pos = i;
+                       }
+               }
+       }
+
+       DB((dbg, LEVEL_4, "loop has 1 own backedge.\n"));
+
+       exit_block = get_nodes_block(loop_info.cf_out.pred);
+       /* The loop has to be tail-controlled.
+        * This can be changed/improved,
+        * but we would need a duff iv. */
+       if (exit_block != loop_block)
+               return NULL;
+
+       DB((dbg, LEVEL_4, "tail-controlled loop.\n"));
+
+       /* find value on which loop exit depends */
+       projx = loop_info.cf_out.pred;
        cond = get_irn_n(projx, 0);
-       projres = get_irn_n(cond, 0);
+       cmp = get_irn_n(cond, 0);
+
+       if (!is_Cmp(cmp))
+               return NULL;
+
+       DB((dbg, LEVEL_5, "projection is %s\n", get_relation_string(get_Proj_proj(projx))));
+
+       switch(get_Proj_proj(projx)) {
+               case pn_Cond_false:
+                       loop_info.exit_cond = 0;
+                       break;
+               case pn_Cond_true:
+                       loop_info.exit_cond = 1;
+                       break;
+               default:
+                       panic("Cond Proj_proj other than true/false");
+       }
+
+       DB((dbg, LEVEL_4, "Valid Cmp.\n"));
+       return cmp;
+}
+
+/* Returns 1 if all nodes are mode_Iu or mode_Is. */
+static unsigned are_mode_I(ir_node *n1, ir_node* n2, ir_node *n3)
+{
+       ir_mode *m1 = get_irn_mode(n1);
+       ir_mode *m2 = get_irn_mode(n2);
+       ir_mode *m3 = get_irn_mode(n3);
+
+       if ((m1 == mode_Iu && m2 == mode_Iu && m3 == mode_Iu) ||
+           (m1 == mode_Is && m2 == mode_Is && m3 == mode_Is))
+               return 1;
+       else
+               return 0;
+}
+
+/* Checks if cur_loop is a simple tail-controlled counting loop
+ * with start and end value loop invariant, step constant. */
+static unsigned get_unroll_decision_invariant(void)
+{
+
+       ir_node   *projres, *loop_condition, *iteration_path;
+       unsigned   success, is_latest_val;
+       ir_tarval *step_tar;
+       ir_mode   *mode;
+
+
+       /* RETURN if loop is not 'simple' */
+       projres = is_simple_loop();
+       if (projres == NULL)
+               return 0;
+
+       /* Use a minimal size for the invariant unrolled loop,
+     * as duffs device produces overhead */
+       if (loop_info.nodes < opt_params.invar_unrolling_min_size)
+               return 0;
+
        loop_condition = get_irn_n(projres, 0);
 
-       DB((dbg, LEVEL_2, " loop condition %N\n", loop_condition));
+       success = get_invariant_pred(loop_condition, &loop_info.end_val, &iteration_path);
+       DB((dbg, LEVEL_4, "pred invar %d\n", success));
+
+       if (! success)
+               return 0;
+
+       DB((dbg, LEVEL_4, "Invariant End_val %N, other %N\n", loop_info.end_val, iteration_path));
+
+       /* We may find the add or the phi first.
+        * Until now we only have end_val. */
+       if (is_Add(iteration_path) || is_Sub(iteration_path)) {
+
+               /* We test against the latest value of the iv. */
+               is_latest_val = 1;
+
+               loop_info.add = iteration_path;
+               DB((dbg, LEVEL_4, "Case 1: Got add %N (maybe not sane)\n", loop_info.add));
+
+               /* Preds of the add should be step and the iteration_phi */
+               success = get_const_pred(loop_info.add, &loop_info.step, &loop_info.iteration_phi);
+               if (! success)
+                       return 0;
+
+               DB((dbg, LEVEL_4, "Got step %N\n", loop_info.step));
+
+               if (! is_Phi(loop_info.iteration_phi))
+                       return 0;
+
+               DB((dbg, LEVEL_4, "Got phi %N\n", loop_info.iteration_phi));
+
+               /* Find start_val.
+                * Does necessary sanity check of add, if it is already set.  */
+               success = get_start_and_add(loop_info.iteration_phi, invariant);
+               if (! success)
+                       return 0;
+
+               DB((dbg, LEVEL_4, "Got start A  %N\n", loop_info.start_val));
+
+       } else if (is_Phi(iteration_path)) {
+               ir_node *new_iteration_phi;
+
+               /* We compare with the value the iv had entering this run. */
+               is_latest_val = 0;
+
+               loop_info.iteration_phi = iteration_path;
+               DB((dbg, LEVEL_4, "Case 2: Got phi %N\n", loop_info.iteration_phi));
+
+               /* Find start_val and add-node.
+                * Does necessary sanity check of add, if it is already set.  */
+               success = get_start_and_add(loop_info.iteration_phi, invariant);
+               if (! success)
+                       return 0;
+
+               DB((dbg, LEVEL_4, "Got start B %N\n", loop_info.start_val));
+               DB((dbg, LEVEL_4, "Got add or sub %N\n", loop_info.add));
+
+               success = get_const_pred(loop_info.add, &loop_info.step, &new_iteration_phi);
+               if (! success)
+                       return 0;
+
+               DB((dbg, LEVEL_4, "Got step (B) %N\n", loop_info.step));
+
+               if (loop_info.iteration_phi != new_iteration_phi)
+                       return 0;
+
+       } else {
+               return 0;
+       }
+
+       mode = get_irn_mode(loop_info.end_val);
+
+       DB((dbg, LEVEL_4, "start %N, end %N, step %N\n",
+                               loop_info.start_val, loop_info.end_val, loop_info.step));
+
+       if (mode != mode_Is && mode != mode_Iu)
+               return 0;
+
+       /* TODO necessary? */
+       if (!are_mode_I(loop_info.start_val, loop_info.step, loop_info.end_val))
+               return 0;
+
+       DB((dbg, LEVEL_4, "mode integer\n"));
+
+       step_tar = get_Const_tarval(loop_info.step);
+
+       if (tarval_is_null(step_tar)) {
+               /* TODO Might be worth a warning. */
+               return 0;
+       }
+
+       DB((dbg, LEVEL_4, "step is not 0\n"));
+
+       create_duffs_block();
+
+       return loop_info.max_unroll;
+}
+
+/* Returns unroll factor,
+ * given maximum unroll factor and number of loop passes. */
+static unsigned get_preferred_factor_constant(ir_tarval *count_tar)
+{
+       ir_tarval *tar_6, *tar_5, *tar_4, *tar_3, *tar_2;
+       unsigned prefer;
+       ir_mode *mode = get_irn_mode(loop_info.end_val);
+
+       tar_6 = new_tarval_from_long(6, mode);
+       tar_5 = new_tarval_from_long(5, mode);
+       tar_4 = new_tarval_from_long(4, mode);
+       tar_3 = new_tarval_from_long(3, mode);
+       tar_2 = new_tarval_from_long(2, mode);
+
+       /* loop passes % {6, 5, 4, 3, 2} == 0  */
+       if (tarval_is_null(tarval_mod(count_tar, tar_6)))
+               prefer = 6;
+       else if (tarval_is_null(tarval_mod(count_tar, tar_5)))
+               prefer = 5;
+       else if (tarval_is_null(tarval_mod(count_tar, tar_4)))
+               prefer = 4;
+       else if (tarval_is_null(tarval_mod(count_tar, tar_3)))
+               prefer = 3;
+       else if (tarval_is_null(tarval_mod(count_tar, tar_2)))
+               prefer = 2;
+       else {
+               /* gcd(max_unroll, count_tar) */
+               int a = loop_info.max_unroll;
+               int b = (int)get_tarval_long(count_tar);
+               int c;
+
+               DB((dbg, LEVEL_4, "gcd of max_unroll %d and count_tar %d: ", a, b));
+
+               do {
+               c = a % b;
+               a = b; b = c;
+               } while( c != 0);
+
+               DB((dbg, LEVEL_4, "%d\n", a));
+               return a;
+       }
+
+       DB((dbg, LEVEL_4, "preferred unroll factor %d\n", prefer));
+
+       /*
+        * If our preference is greater than the allowed unroll factor
+        * we either might reduce the preferred factor and prevent a duffs device block,
+        * or create a duffs device block, from which in this case (constants only)
+        * we know the startloop at compiletime.
+        * The latter yields the following graphs.
+        * but for code generation we would want to use graph A.
+        * The graphs are equivalent. So, we can only reduce the preferred factor.
+        * A)                   B)
+        *     PreHead             PreHead
+        *        |      ,--.         |   ,--.
+        *         \ Loop1   \        Loop2   \
+        *          \  |     |       /  |     |
+        *           Loop2   /      / Loop1   /
+        *           |   `--'      |      `--'
+        */
+
+       if (prefer <= loop_info.max_unroll)
+               return prefer;
+       else {
+               switch(prefer) {
+                       case 6:
+                               if (loop_info.max_unroll >= 3)
+                                       return 3;
+                               else if (loop_info.max_unroll >= 2)
+                                       return 2;
+                               else
+                                       return 0;
+
+                       case 4:
+                               if (loop_info.max_unroll >= 2)
+                                       return 2;
+                               else
+                                       return 0;
+
+                       default:
+                               return 0;
+               }
+       }
+}
+
+/* Check if cur_loop is a simple counting loop.
+ * Start, step and end are constants.
+ * TODO The whole constant case should use procedures similar to
+ * the invariant case, as they are more versatile. */
+/* TODO split. */
+static unsigned get_unroll_decision_constant(void)
+{
+       ir_node     *cmp, *iteration_path;
+       unsigned     success, is_latest_val;
+       ir_tarval   *start_tar, *end_tar, *step_tar, *diff_tar, *count_tar;
+       ir_tarval   *stepped;
+       ir_relation  proj_proj, norm_proj;
+       ir_mode     *mode;
+
+       /* RETURN if loop is not 'simple' */
+       cmp = is_simple_loop();
+       if (cmp == NULL)
+               return 0;
 
-       /* One in of the loop condition needs to be loop invariant.
-        * The other in is assigned by an add.
-        * The add uses a loop invariant value
-        * and another value that depends on a loop invariant start value and the add itself.
+       /* One in of the loop condition needs to be loop invariant. => end_val
+        * The other in is assigned by an add. => add
+        * The add uses a loop invariant value => step
+        * and a phi with a loop invariant start_val and the add node as ins.
 
           ^   ^
           |   | .-,
           |   Phi |
                \  |   |
-                Add  /
-             |__/
+         ^  Add   |
+          \  | \__|
+           cond
+            /\
        */
 
-       end_val = NULL;
-       /* Find the loop invariant in */
-       /* Assumption that condition is cmp or mod.
-          TODO other? */
-       pred0 = get_irn_n(loop_condition, 0);
-       pred1 = get_irn_n(loop_condition, 1);
+       success = get_const_pred(cmp, &loop_info.end_val, &iteration_path);
+       if (! success)
+               return 0;
 
-       if (is_loop_invariant_val(pred0)) {
-               end_val = pred0;
-               iteration = pred1;
-       }
+       DB((dbg, LEVEL_4, "End_val %N, other %N\n", loop_info.end_val, iteration_path));
+
+       /* We may find the add or the phi first.
+        * Until now we only have end_val. */
+       if (is_Add(iteration_path) || is_Sub(iteration_path)) {
 
+               /* We test against the latest value of the iv. */
+               is_latest_val = 1;
 
-       if (is_loop_invariant_val(pred1)) {
-               if (end_val != NULL)
-                       /* RETURN. loop condition does not change during the loop. */
+               loop_info.add = iteration_path;
+               DB((dbg, LEVEL_4, "Case 2: Got add %N (maybe not sane)\n", loop_info.add));
+
+               /* Preds of the add should be step and the iteration_phi */
+               success = get_const_pred(loop_info.add, &loop_info.step, &loop_info.iteration_phi);
+               if (! success)
                        return 0;
 
-               end_val = pred1;
-               iteration = pred0;
-       }
+               DB((dbg, LEVEL_4, "Got step %N\n", loop_info.step));
+
+               if (! is_Phi(loop_info.iteration_phi))
+                       return 0;
 
-       DB((dbg, LEVEL_2, " end_val %N\n", end_val));
+               DB((dbg, LEVEL_4, "Got phi %N\n", loop_info.iteration_phi));
 
-       /* Check for constraint of remaining in. */
-       add = is_loop_iteration(iteration);
-       if (! add)
-               return 0;
+               /* Find start_val.
+                * Does necessary sanity check of add, if it is already set.  */
+               success = get_start_and_add(loop_info.iteration_phi, constant);
+               if (! success)
+                       return 0;
 
-       DB((dbg, LEVEL_2, " add %N\n", add));
+               DB((dbg, LEVEL_4, "Got start %N\n", loop_info.start_val));
 
-       add_in0 = get_irn_n(add, 0);
-       add_in1 = get_irn_n(add, 1);
+       } else if (is_Phi(iteration_path)) {
+               ir_node *new_iteration_phi;
 
-       if (is_loop_invariant_val(add_in0)) {
-               step = add_in0;
-               iteration_phi = add_in1;
-       }
+               /* We compare with the value the iv had entering this run. */
+               is_latest_val = 0;
+
+               loop_info.iteration_phi = iteration_path;
+               DB((dbg, LEVEL_4, "Case 1: Got phi %N \n", loop_info.iteration_phi));
 
-       if (is_loop_invariant_val(add_in1)) {
-               if (step != NULL)
+               /* Find start_val and add-node.
+                * Does necessary sanity check of add, if it is already set.  */
+               success = get_start_and_add(loop_info.iteration_phi, constant);
+               if (! success)
                        return 0;
-               step = add_in1;
-               iteration_phi = add_in0;
-       }
 
-       DB((dbg, LEVEL_2, " step %N\n", step));
+               DB((dbg, LEVEL_4, "Got start %N\n", loop_info.start_val));
+               DB((dbg, LEVEL_4, "Got add or sub %N\n", loop_info.add));
 
-       if (! is_Phi(iteration_phi)) {
-               if (is_Phi(iteration))
-                       iteration_phi = iteration;
-               else
+               success = get_const_pred(loop_info.add, &loop_info.step, &new_iteration_phi);
+               if (! success)
+                       return 0;
+
+               DB((dbg, LEVEL_4, "Got step %N\n", loop_info.step));
+
+               if (loop_info.iteration_phi != new_iteration_phi)
                        return 0;
+
+       } else {
+               /* RETURN */
+               return 0;
        }
 
-       DB((dbg, LEVEL_2, " #### COUNTING LOOP step %N end %N phi %N\n", step, end_val, iteration_phi));
+       mode = get_irn_mode(loop_info.end_val);
 
-#if 0
-       phi for startval
+       DB((dbg, LEVEL_4, "start %N, end %N, step %N\n",
+                               loop_info.start_val, loop_info.end_val, loop_info.step));
 
-       mode = get_irn_mode(add);
+       if (mode != mode_Is && mode != mode_Iu)
+               return 0;
 
-       block = new_Block(0, NULL);
-       /*set_irg_current_Block(current_ir_graph, block);*/
+       /* TODO necessary? */
+       if (!are_mode_I(loop_info.start_val, loop_info.step, loop_info.end_val))
+               return 0;
 
-       /*TODO*/
-       unroll_mod_const = new_Const(unroll_number);
-       module = new_r_Mod(block, new_NoMem(), end_val, step, mode, op_pin_state_pinned);
-       /*new_Proj();*/
+       DB((dbg, LEVEL_4, "mode integer\n"));
 
+       end_tar = get_Const_tarval(loop_info.end_val);
+       start_tar = get_Const_tarval(loop_info.start_val);
+       step_tar = get_Const_tarval(loop_info.step);
 
-#endif
-       return 0;
+       if (tarval_is_null(step_tar))
+               /* TODO Might be worth a warning. */
+               return 0;
+
+       DB((dbg, LEVEL_4, "step is not 0\n"));
+
+       if ((!tarval_is_negative(step_tar)) ^ (!is_Sub(loop_info.add)))
+               loop_info.decreasing = 1;
+
+       diff_tar = tarval_sub(end_tar, start_tar, mode);
+
+       /* We need at least count_tar steps to be close to end_val, maybe more.
+        * No way, that we have gone too many steps.
+        * This represents the 'latest value'.
+        * (If condition checks against latest value, is checked later) */
+       count_tar = tarval_div(diff_tar, step_tar);
+
+       /* Iv will not pass end_val (except overflows).
+        * Nothing done, as it would yield to no advantage. */
+       if (tarval_is_negative(count_tar)) {
+               DB((dbg, LEVEL_4, "Loop is endless or never taken."));
+               /* TODO Might be worth a warning. */
+               return 0;
+       }
+
+       count_stats(stats.u_simple_counting_loop);
+
+       loop_info.latest_value = is_latest_val;
+
+       /* TODO split here
+       if (! is_simple_counting_loop(&count_tar))
+               return 0;
+       */
+
+       /* stepped can be negative, if step < 0 */
+       stepped = tarval_mul(count_tar, step_tar);
+
+       /* step as close to end_val as possible, */
+       /* |stepped| <= |end_tar|, and dist(stepped, end_tar) is smaller than a step. */
+       if (is_Sub(loop_info.add))
+               stepped = tarval_sub(start_tar, stepped, mode_Is);
+       else
+               stepped = tarval_add(start_tar, stepped);
+
+       DB((dbg, LEVEL_4, "stepped to %ld\n", get_tarval_long(stepped)));
+
+       proj_proj = get_Cmp_relation(cmp);
+       /* Assure that norm_proj is the stay-in-loop case. */
+       if (loop_info.exit_cond == 1)
+               norm_proj = get_negated_relation(proj_proj);
+       else
+               norm_proj = proj_proj;
+
+       DB((dbg, LEVEL_4, "normalized projection %s\n", get_relation_string(norm_proj)));
+       /* Executed at most once (stay in counting loop if a Eq b) */
+       if (norm_proj == ir_relation_equal)
+               /* TODO Might be worth a warning. */
+               return 0;
+
+       /* calculates next values and increases count_tar according to it */
+       success = simulate_next(&count_tar, stepped, step_tar, end_tar, norm_proj);
+       if (! success)
+               return 0;
+
+       /* We run loop once more, if we compare to the
+        * not yet in-/decreased iv. */
+       if (is_latest_val == 0) {
+               DB((dbg, LEVEL_4, "condition uses not latest iv value\n"));
+               count_tar = tarval_add(count_tar, get_tarval_one(mode));
+       }
+
+       DB((dbg, LEVEL_4, "loop taken %ld times\n", get_tarval_long(count_tar)));
+
+       /* Assure the loop is taken at least 1 time. */
+       if (tarval_is_null(count_tar)) {
+               /* TODO Might be worth a warning. */
+               return 0;
+       }
+
+       loop_info.count_tar = count_tar;
+       return get_preferred_factor_constant(count_tar);
 }
-#endif
 
 /**
  * Loop unrolling
  */
 static void unroll_loop(void)
 {
-       int i;
-       unsigned unroll_number;
-       out_edge *ssa_outs;
-       cur_loop_outs = NEW_ARR_F(out_edge, 0);
-
-       /* Get loop outs */
-       irg_walk_graph(current_ir_graph, get_loop_outs, NULL, NULL);
 
-       unroll_number = get_unroll_decision(cur_loop_outs);
+       if (! (loop_info.nodes > 0))
+               return;
 
-       /*dump_ir_block_graph(current_ir_graph, "-pre");*/
+#if LOOP_IGNORE_NODE_LIMITS
+       DB((dbg, LEVEL_1, "WARNING: Loop node limitations ignored."));
+#else
+       if (loop_info.nodes > opt_params.max_unrolled_loop_size) {
+               DB((dbg, LEVEL_2, "Nodes %d > allowed nodes %d\n",
+                       loop_info.nodes, opt_params.max_unrolled_loop_size));
+               count_stats(stats.too_large);
+               return;
+       }
 
-       if (unroll_number) {
-               create_duffs_device(unroll_number);
+       if (loop_info.calls > 0) {
+               DB((dbg, LEVEL_2, "Calls %d > allowed calls 0\n",
+                       loop_info.calls));
+               count_stats(stats.calls_limit);
+               return;
+       }
+#endif
 
-               /* Copies the loop and allocs node_info */
-               copy_loop(cur_loop_outs, unroll_number - 1);
-               /*dump_ir_block_graph(current_ir_graph, "-cp");*/
+       unroll_nr = 0;
 
-               /* Line up the floating copies. */
-               place_copies(unroll_number - 1);
-               /*dump_ir_block_graph(current_ir_graph, "-ord");*/
+       /* get_unroll_decision_constant and invariant are completely
+        * independent for flexibility.
+        * Some checks may be performed twice. */
 
-               /* Extend loop successors */
-               ssa_outs = extend_ins(cur_loop_outs, unroll_number - 1);
-               /*dump_ir_block_graph(current_ir_graph, "-fixed")*/ ;
+       /* constant case? */
+       if (opt_params.allow_const_unrolling)
+               unroll_nr = get_unroll_decision_constant();
+       if (unroll_nr > 1) {
+               loop_info.unroll_kind = constant;
 
-               /* Links are going to be overwritten */
-               free_node_info_blocks();
+       } else {
+               /* invariant case? */
+               if (opt_params.allow_invar_unrolling)
+                       unroll_nr = get_unroll_decision_invariant();
+               if (unroll_nr > 1)
+                       loop_info.unroll_kind = invariant;
+       }
 
-               /* Generate phis for all loop outs */
-               for (i = 0; i < ARR_LEN(ssa_outs); ++i) {
-                       out_edge entry = ssa_outs[i];
-                       ir_node *node = entry.node;
-                       ir_node *pred = get_irn_n(entry.node, entry.pos);
+       DB((dbg, LEVEL_2, " *** Unrolling %d times ***\n", unroll_nr));
 
-                       DB((dbg, LEVEL_5, "Do? construct_ssa_n def %N  node %N  pos %d\n",
-                                       pred, node, entry.pos));
+       if (unroll_nr > 1) {
+               loop_entries = NEW_ARR_F(entry_edge, 0);
 
-                       if (!is_End(node)) {
-                               DB((dbg, LEVEL_5, "construct_ssa_n def %N  node %N  pos %d\n",
-                                                       pred, node, entry.pos));
+               /* Get loop outs */
+               irg_walk_graph(current_ir_graph, get_loop_entries, NULL, NULL);
 
-                               construct_ssa_n(pred, node, unroll_number - 1);
-                               /*if (new_phi)
-                                       construct_ssa_n(pred, new_phi, unroll_number - 1);*/
-                       }
+               if (loop_info.unroll_kind == constant) {
+                       if ((int)get_tarval_long(loop_info.count_tar) == unroll_nr)
+                               loop_info.needs_backedge = 0;
+                       else
+                               loop_info.needs_backedge = 1;
+               } else {
+                       loop_info.needs_backedge = 1;
                }
-               /*dump_ir_block_graph(current_ir_graph, "-ssa-done");*/
 
-               /* FREE */
-               free_node_info();
+               /* Use phase to keep copy of nodes from the condition chain. */
+               phase = new_phase(current_ir_graph, phase_irn_init_default);
+
+               /* Copies the loop */
+               copy_loop(loop_entries, unroll_nr - 1);
+
+               /* Line up the floating copies. */
+               place_copies(unroll_nr - 1);
 
+               /* Remove phis with 1 in
+                * If there were no nested phis, this would not be necessary.
+                * Avoiding the creation in the first place
+                * leads to complex special cases. */
                irg_walk_graph(current_ir_graph, correct_phis, NULL, NULL);
 
-               DEL_ARR_F(ssa_outs);
+               if (loop_info.unroll_kind == constant)
+                       count_stats(stats.constant_unroll);
+               else
+                       count_stats(stats.invariant_unroll);
 
                set_irg_doms_inconsistent(current_ir_graph);
                set_irg_loopinfo_inconsistent(current_ir_graph);
+               /* TODO is it? */
                set_irg_outs_inconsistent(current_ir_graph);
+
+               DEL_ARR_F(loop_entries);
        }
-       DEL_ARR_F(cur_loop_outs);
+
 }
 
-/* Initialization and */
+/* Analyzes the loop, and checks if size is within allowed range.
+ * Decides if loop will be processed. */
 static void init_analyze(ir_loop *loop)
 {
-       /* Init new for every loop */
        cur_loop = loop;
 
        loop_head = NULL;
        loop_head_valid = 1;
-       loop_inv_head = NULL;
-       loop_peeled_head = NULL;
 
-       loop_info.calls = 0;
-       loop_info.blocks = 0;
-       loop_info.cf_outs = 0;
+       /* Reset loop info */
+       memset(&loop_info, 0, sizeof(loop_info_t));
 
-       DB((dbg, LEVEL_2, "          >>>> current loop includes node %N <<<\n",
-               get_loop_node(loop, 0)));
+       DB((dbg, LEVEL_1, "    >>>> current loop includes node %N <<<\n",
+               get_loop_node(loop, 0)));
 
+       /* Collect loop informations: head, node counts. */
        irg_walk_graph(current_ir_graph, get_loop_info, NULL, NULL);
 
        /* RETURN if there is no valid head */
        if (!loop_head || !loop_head_valid) {
-               DB((dbg, LEVEL_2,   "No valid loop head. Nothing done.\n"));
+               DB((dbg, LEVEL_1,   "No valid loop head. Nothing done.\n"));
                return;
+       } else {
+               DB((dbg, LEVEL_1,   "Loophead: %N\n", loop_head));
        }
 
-       DB((dbg, LEVEL_2,   "Loophead: %N\n", loop_head));
+       if (loop_info.branches > opt_params.max_branches) {
+               DB((dbg, LEVEL_1, "Branches %d > allowed branches %d\n",
+                       loop_info.branches, opt_params.max_branches));
+               count_stats(stats.calls_limit);
+               return;
+       }
 
-       if (enable_inversion)
-               loop_inversion();
+       switch (loop_op) {
+               case loop_op_inversion:
+                       loop_inversion();
+                       break;
 
-       if (enable_unrolling)
-               unroll_loop();
+               case loop_op_unrolling:
+                       unroll_loop();
+                       break;
 
-       DB((dbg, LEVEL_2, "             <<<< end of loop with node %N >>>>\n",
-               get_loop_node(loop, 0)));
+               default:
+                       panic("Loop optimization not implemented.");
+       }
+       DB((dbg, LEVEL_1, "       <<<< end of loop with node %N >>>>\n",
+               get_loop_node(loop, 0)));
 }
 
-/* Find most inner loops and send them to analyze_loop */
-static void find_most_inner_loop(ir_loop *loop)
+/* Find innermost loops and add them to loops. */
+static void find_innermost_loop(ir_loop *loop)
 {
        /* descend into sons */
-       int sons = get_loop_n_sons(loop);
+       size_t sons = get_loop_n_sons(loop);
 
        if (sons == 0) {
                ARR_APP1(ir_loop *, loops, loop);
        } else {
-               int s;
-               for (s=0; s<sons; s++) {
-                       find_most_inner_loop(get_loop_son(loop, s));
+               size_t s;
+               for (s = 0; s < sons; ++s) {
+                       find_innermost_loop(get_loop_son(loop, s));
                }
        }
 }
 
-/**
- * Assure preconditions are met and go through all loops.
- */
+static void set_loop_params(void)
+{
+    opt_params.max_loop_size = 100;
+    opt_params.depth_adaption = -50;
+    opt_params.count_phi = 1;
+    opt_params.count_proj = 0;
+    opt_params.allowed_calls = 0;
+
+    opt_params.max_cc_size = 5;
+
+
+    opt_params.allow_const_unrolling = 1;
+    opt_params.allow_invar_unrolling = 0;
+
+    opt_params.invar_unrolling_min_size = 20;
+    opt_params.max_unrolled_loop_size = 400;
+    opt_params.max_branches = 9999;
+}
+
+/* Assure preconditions are met and go through all loops. */
 void loop_optimization(ir_graph *irg)
 {
        ir_loop *loop;
-       int     i, sons, nr;
+       size_t  sons, nr;
+       size_t  i;
+
+       set_loop_params();
+
+       /* Reset stats for this procedure */
+       reset_stats();
 
-       /* Init */
-       free_list = NULL;
+       /* Preconditions */
        set_current_ir_graph(irg);
 
        edges_assure(irg);
@@ -1961,23 +2757,30 @@ void loop_optimization(ir_graph *irg)
        loops = NEW_ARR_F(ir_loop *, 0);
        /* List all inner loops */
        for (nr = 0; nr < sons; ++nr) {
-               find_most_inner_loop(get_loop_son(loop, nr));
+               find_innermost_loop(get_loop_son(loop, nr));
        }
 
        ir_reserve_resources(irg, IR_RESOURCE_IRN_LINK);
-       /* Set all links NULL */
+       /* Set all links to NULL */
        irg_walk_graph(current_ir_graph, reset_link, NULL, NULL);
 
        for (i = 0; i < ARR_LEN(loops); ++i) {
                ir_loop *loop = loops[i];
+
+               count_stats(stats.loops);
+
+               /* Analyze and handle loop */
                init_analyze(loop);
 
-               /*dump_ir_block_graph(current_ir_graph, "-part");*/
+               /* Copied blocks do not have their phi list yet */
                collect_phiprojs(irg);
+
+               /* Set links to NULL
+                * TODO Still necessary? */
                irg_walk_graph(current_ir_graph, reset_link, NULL, NULL);
        }
 
-       /*dump_ir_block_graph(current_ir_graph, "-full");*/
+       print_stats();
 
        DEL_ARR_F(loops);
        ir_free_resources(irg, IR_RESOURCE_IRN_LINK);
@@ -1986,46 +2789,42 @@ void loop_optimization(ir_graph *irg)
 
 void do_loop_unrolling(ir_graph *irg)
 {
-       enable_unrolling = 1;
-       enable_peeling = 0;
-       enable_inversion = 0;
+       loop_op = loop_op_unrolling;
 
-       DB((dbg, LEVEL_2, " >>> unrolling (Startnode %N) <<<\n",
+       DB((dbg, LEVEL_1, " >>> unrolling (Startnode %N) <<<\n",
                                get_irg_start(irg)));
 
        loop_optimization(irg);
 
-       DB((dbg, LEVEL_2, " >>> unrolling done (Startnode %N) <<<\n",
+       DB((dbg, LEVEL_1, " >>> unrolling done (Startnode %N) <<<\n",
                                get_irg_start(irg)));
 }
 
 void do_loop_inversion(ir_graph *irg)
 {
-       enable_unrolling = 0;
-       enable_peeling = 0;
-       enable_inversion = 1;
+       loop_op = loop_op_inversion;
 
-       DB((dbg, LEVEL_2, " >>> inversion (Startnode %N) <<<\n",
+       DB((dbg, LEVEL_1, " >>> inversion (Startnode %N) <<<\n",
                                get_irg_start(irg)));
 
        loop_optimization(irg);
 
-       DB((dbg, LEVEL_2, " >>> inversion done (Startnode %N) <<<\n",
+       assure_cf_loop(irg);
+
+       DB((dbg, LEVEL_1, " >>> inversion done (Startnode %N) <<<\n",
                                get_irg_start(irg)));
 }
 
 void do_loop_peeling(ir_graph *irg)
 {
-       enable_unrolling = 0;
-       enable_peeling = 1;
-       enable_inversion = 0;
+       loop_op = loop_op_peeling;
 
-       DB((dbg, LEVEL_2, " >>> peeling (Startnode %N) <<<\n",
+       DB((dbg, LEVEL_1, " >>> peeling (Startnode %N) <<<\n",
                                get_irg_start(irg)));
 
        loop_optimization(irg);
 
-       DB((dbg, LEVEL_2, " >>> peeling done (Startnode %N) <<<\n",
+       DB((dbg, LEVEL_1, " >>> peeling done (Startnode %N) <<<\n",
                                get_irg_start(irg)));
 
 }