X-Git-Url: http://nsz.repo.hu/git/?a=blobdiff_plain;f=ir%2Fopt%2Floop_unrolling.c;h=97c381721a8a7a8296f5287a86e85dd02d20e71d;hb=229c9d24147d83fb3160da88436c3b95fb1b2b1b;hp=459b1c24c7c02691946c2b0d2fafc8c7dbd98512;hpb=e3ca3cde843544042eb2e3c953510f70cb36b818;p=libfirm

diff --git a/ir/opt/loop_unrolling.c b/ir/opt/loop_unrolling.c
index 459b1c24c..97c381721 100644
--- a/ir/opt/loop_unrolling.c
+++ b/ir/opt/loop_unrolling.c
@@ -12,29 +12,961 @@
  * Copyright:   (c) 2004 Universität Karlsruhe
  * Licence:     This file protected by GPL -  GNU GENERAL PUBLIC LICENSE.
  */
+#ifdef HAVE_CONFIG_H
+#include "config.h"
+#endif
 
+#ifdef HAVE_STRING_H
+#include <string.h>
+#endif
+#ifdef HAVE_MALLOC_H
+#include <malloc.h>
+#endif
+#ifdef HAVE_ALLOCA_H
+#include <alloca.h>
+#endif
 
-# include "loop_unrolling.h"
+#include "loop_unrolling.h"
 
-# include "irgwalk.h"
-# include "irnode_t.h"
-# include "irloop_t.h"
+#include "irnode_t.h"
+#include "irgwalk.h"
+#include "ircons.h"
+#include "irgmod.h"
+#include "irloop_t.h"
+#include "irgopt_t.h"
+#include "irouts.h"
+#include "trouts.h"
+#include "hashptr.h"
+#include "pset.h"
+#include "strength_red.h"
+#include "compute_loop_info.h"
+#include "irdump.h"
+#include "irtools.h"
 
-static void do_loop_unroll(ir_node *n, void *env){
+/* We will unroll maximal 4-times.  */
+#define MAX_UNROLL 4
+
+/* We will know if the head of the loop to be copy.
+ * Default "0"  don't copy.*/
+static int copy_loop_head;
+
+typedef struct {
+  ir_node *irn ;                /* Node of the loop to be unrolling*/
+  ir_node *copy[MAX_UNROLL] ;   /* The copy of the node */
+} copies_t;
+
+/**
+ * Compare two elements of the copies_t set
+ */
+static int set_cmp(const void *elt, const void *key, size_t size)
+{
+  const copies_t *c1 = elt;
+  const copies_t *c2 = key;
+
+  return c1->irn != c2->irn;
+}
+
+/**
+ * Remember the new node in the old node by using a field all nodes have.
+ */
+static INLINE void
+set_new_node (ir_node *old, ir_node *new)
+{
+  old->link = new;
+}
+
+/*Check if phi in the loop head is.
+ *
+ * @param phi               Must be a phi node from the loop.
+ * @param loop_head         The loop head .
+ */
+static int is_Phi_in_loop_head(ir_node *phi, ir_node *loop_head) {
+  assert(is_Block(loop_head));
+  return is_Phi(phi) && (get_nodes_block(phi) == loop_head);
+}
+
+/**
+ * Copies predecessors of node to copies of node.
+ * If the predecessor is a loop invariant, then the copy get it
+ * as predecessor, else the copy of the predecessor.
+ *
+ * @param l_n                A set, where the node of the loop are saved.
+ * @param value              A element of the set.
+ * @param info               Contains information about the induction variable.
+ * @param unroll_factor      A integer 2 <= unroll_factor <= 4.
+ * @param env                Free environment pointer.
+ */
+static void
+set_preds (set *l_n, copies_t *value, induct_var_info *info, int unroll_factor, void *env)
+{
+  ir_node *loop_head;
+  int i, p, irn_arity;
+  copies_t key, *value_pred;
+  if(value->copy[0] == NULL ||
+     get_irn_op(value->irn) != get_irn_op(value->copy[0]))
+    return;
+
+  /* The head of the unrolling loop. */
+  loop_head = get_loop_node(info->l_itervar_phi, 0);
+  irn_arity = get_irn_arity(value->irn);
+
+  for (i = 0; i < irn_arity; i++) {
+    ir_node *pred = get_irn_n(value->irn, i);
+
+    key.irn = pred;
+    value_pred = set_find(l_n, &key, sizeof(key), HASH_PTR(pred));
+
+    if (value->irn != loop_head && !is_Phi_in_loop_head(value->irn, loop_head)) {
+      if (value_pred == NULL) {
+	      /* Is loop invariant. */
+	      for (p = 0; p < unroll_factor - 1; p++)
+	        set_irn_n(value->copy[p], i, pred);
+  	      /* pred is a loop invariant. The copies of the successors get it as predecessor. */
+      }
+      else {
+	      for (p = 0; p < unroll_factor - 1; p++)
+	        set_irn_n(value->copy[p], i, value_pred->copy[p]);
+          /* value_pred->irn is a node from the unrolling loop.
+           * The copies of the successors get the
+	         * copies of value_pred as predecessor.
+           */
+      }
+    }
+  }
+}
+
+/* Set the backedge of phi in the loop head.The backedge of phis in the loop head
+ * must now point to the value defined
+ * in the last copy of the loop body.
+ *
+ * @param l_n                A set, where the node of the loop are saved.
+ * @param value              A phi in the loop head.
+ * @param info               Contains information about the induction variable.
+ * @param unroll_factor      A integer 2 <= unroll_factor <= 4.
+ */
+static void
+set_phi_backedge(set *l_n, copies_t *value, induct_var_info *info, int unroll_factor)
+{
+  copies_t key, *value_pred;
+
+  /* info->op_pred_pos is the backedge position. */
+  key.irn = get_irn_n(value->irn, info->op_pred_pos);
+  value_pred = set_find(l_n, &key, sizeof(key), HASH_PTR(key.irn));
+
+  /* value->copy[unroll_factor - 2] is the last copy. */
+  set_Phi_pred(value->irn, info->op_pred_pos, value_pred->copy[unroll_factor - 2]);
+}
+
+/**
+ * Test for a loop head.
+ *
+ * Returns true if the node has predecessors in the loop _and_ out of
+ * the loop.  Then it is a loop head: The loop can be entered through
+ * this node.
+ *
+ * @param n      The node to be tested. Must be a block.
+ * @param info   Contains the loop information.
+ */
+static int
+is_loop_head(ir_node *n, induct_var_info *info)
+{
+  int i, arity;
+  int some_outof_loop = 0, some_in_loop = 0;
+
+  assert(get_irn_op(n) == op_Block);
+  arity = get_Block_n_cfgpreds(n);
+
+  for (i = 0; i < arity; i++) {
+    ir_node *pred = get_Block_cfgpred(n, i);
+    assert(pred);
+    if (is_loop_invariant(pred, get_loop_node(info->l_itervar_phi, 0))) {
+      some_outof_loop = 1;
+    } else
+      some_in_loop = 1;
+  }
+
+  return some_outof_loop && some_in_loop;
+}
+
+
+/**
+ * Test whether the passed loop is a natural loop.
+ *
+ * Returns true if the loop has only one loop header and only a single
+ * back edge.
+ *
+ * @param info  Contains the loop information.
+ */
+static int
+is_natural_loop(induct_var_info *info)
+{
+  ir_node *l_node;
+  int l_n_node = 0, i;
+
+  l_n_node = get_loop_n_nodes (info->l_itervar_phi);
+
+  for (i = 1; i < (l_n_node); i ++) {
+    l_node = get_loop_node (info->l_itervar_phi, i);
+    if (is_loop_head(l_node, info)) return 0;
+
+    if (has_backedges(l_node) && i != l_n_node-1) return 0;
+  }
+
+  return 1;
+}
+
+/**
+ * Search for all nodes of a loop.
+ *
+ * @param node       The induction variable of the loop.
+ * @param loop_head  The head of the loop.
+ * @param l_n        A set, where the node of the loop are saved.
+ */
+static void
+find_loop_nodes(ir_node *node, ir_node *loop_head, set *l_n)
+{
+  int i;
+  copies_t key, *value;
+
+  /* Add this node to the list. */
+  key.irn  = node;
+
+  /* Initialize all copies of the added node with NULL.*/
+  for (i = 0; i < 4; ++i)
+    key.copy[i] = NULL;
+  value = set_insert(l_n, &key, sizeof(key), HASH_PTR(key.irn));
+
+  /* Add all outs of this node to the list, if they are within the loop. */
+  for (i = get_irn_n_outs(node) - 1; i >= 0; --i) {
+    ir_node *pred = get_irn_out(node, i);
+
+    key.irn = pred;
+    if (!is_loop_invariant(pred, loop_head)         &&
+	    set_find( l_n, &key, sizeof(key), HASH_PTR(key.irn)) == NULL ) {
+      find_loop_nodes(pred, loop_head, l_n);
+    }
+  }
+
+  /* Add all ins if they are within the loop. */
+  for (i = get_irn_arity(node) - 1; i >=0; --i) {
+    ir_node *pred = get_irn_n(node, i);
+
+    key.irn = pred;
+    if (!is_loop_invariant(pred, loop_head)         &&
+	      set_find( l_n, &key, sizeof(key), HASH_PTR(key.irn)) == NULL ) {
+      find_loop_nodes(pred, loop_head, l_n);
+    }
+  }
+}
+
+/**
+ * Make a new loop head if copy_head = 1.
+ *
+ * @param l_n              A set, where the node of the loop are saved.
+ * @param info             Contains the loop information.
+ * @param value            A element of the set.
+ * @param unroll_factor    A integer 2 <= unroll_factor <= 4.
+ * @param copy_head        if non-zero, the loop head will be copied
+ *
+ */
+static void
+new_loop_head(set *l_n, induct_var_info *info, copies_t *value, int unroll_factor, int copy_head)
+{
+  int i;
+  copies_t block, *value_backedge_jmp, *backedge_jmp_block;
+  /* The  predecessor of the loop head in the  backedge position */
+  ir_node *backedge_jmp = get_Block_cfgpred(value->irn, info->op_pred_pos);
+
+  block.irn          = backedge_jmp;
+  value_backedge_jmp = set_find(l_n, &block, sizeof(block), HASH_PTR(block.irn));
+
+  if (copy_head) {
+    /* The first copy of the loop head must point to the loop head.*/
+    value->copy[0] = new_Block(1, &backedge_jmp);
+    if(info->l_itervar_phi->flags & do_loop){
+      value_backedge_jmp->copy[0] = new_r_Jmp(current_ir_graph, value->copy[0]);
+      for (i = 1; i < unroll_factor - 1; ++i) {
+      /* all other copies must point to the copy before it in the array. */
+      value->copy[i] = new_Block(1, &backedge_jmp);
+      value_backedge_jmp->copy[i] = new_r_Jmp(current_ir_graph, value->copy[i]);
+      }
+      for (i = 1; i < unroll_factor - 1; ++i){
+	set_nodes_block(value_backedge_jmp->copy[i-1], get_nodes_block(backedge_jmp));
+	set_Block_cfgpred (value->copy[i], 0, value_backedge_jmp->copy[i-1]);
+      }
+    }else
+      for (i = 1; i < unroll_factor - 1; ++i) {
+	/* all other copies must point to the copy before it in the array. */
+	set_nodes_block(value_backedge_jmp->copy[i-1], get_nodes_block(backedge_jmp));
+	value->copy[i] = new_Block(1, &value_backedge_jmp->copy[i-1]);
+      }
+  }
+  else {
+    /* If the loop head must not be copy. block.irn is the successor of the loop head.*/
+    block.irn          = get_nodes_block(backedge_jmp);
+    backedge_jmp_block = set_find(l_n, &block, sizeof(block), HASH_PTR(block.irn));
+
+    /* The first copy of block.irn point to it.
+      The another copies muss point to the copy before it in the array.*/
+    set_irn_n(backedge_jmp_block->copy[0], 0, value_backedge_jmp->irn) ;
+
+    for (i = 1; i < unroll_factor - 1; ++i)
+      set_irn_n(backedge_jmp_block->copy[i], 0, value_backedge_jmp->copy[i - 1]);
+  }
+}
+
+/* Set all copies of the induction variable.
+ *
+ * @param phi             A phi node in the loop head block.
+ * @param phi_pred        The predecessor of the phi along the backedge.
+ * @param unroll_factor   A integer 2 <= unroll_factor <= 4.
+ */
+static void
+set_Phi_copies(copies_t *phi, copies_t *phi_pred, int unroll_factor)
+{
+  int p;
+
+  if(phi_pred != NULL){
+    /* The first copy of Phi node get the node along the backedge as predecessor. The next copies
+       the copies of this node.*/
+    phi->copy[0] = phi_pred->irn;
+    for (p = 1; p < unroll_factor - 1; ++p) {
+      /* If two phi nodes are in cycle.  */
+      if (phi_pred->copy[p - 1] == NULL && get_irn_op(phi_pred->irn) == op_Phi) {
+	if (p & 1)
+	  phi->copy[p] =  phi->irn;
+	else
+	  phi->copy[p] =  phi_pred->irn;
+      } else
+	phi->copy[p] =  phi_pred->copy[p - 1];
+    }
+  }else
+    /* The predecessors of phi are loop invariant and the copies von phi
+       must be phi it self.*/
+    for(p = 0; p < unroll_factor - 1; ++p)
+      phi->copy[p] = phi->irn;
+}
+
+/**
+ * Decide if the loop head must be copied. A head with important nodes
+ * must be copied.
+ *
+ * @param l_n         A set, where the node of the loop are saved.
+ * @param info        Contains information about the induction variable.
+ *
+ * @return non-zero if the loop head must be copied
+ */
+static int
+loop_head_nodes(set *l_n, induct_var_info *info)
+{
+  int must_copy = 0;
+  copies_t *value;
+  ir_node *loop_head = get_loop_node(info->l_itervar_phi, 0);
+
+  for (value = set_first(l_n); value != NULL; value = set_next(l_n))
+    if (is_no_Block(value->irn) && get_nodes_block(value->irn) == loop_head)
+      /* If the loop head contains just this nodes, than must not be copy. */
+      switch (get_irn_opcode(value->irn)) {
+      case iro_Cond:
+	      break;
+      case iro_Phi:
+	      break;
+      case iro_Proj:
+	      break;
+      case iro_Const:
+	      break;
+      case iro_Cmp:
+	      break;
+      default:
+	      must_copy = 1;
+      }
+    return must_copy;
+}
+
+/** Copy all loop nodes.
+ *
+ * @param l_n             Contains all nodes of the loop.
+ * @param info            Contains the loop information.
+ * @param unroll_factor   A integer 2 <= unroll_factor <= 4.
+ */
+static void
+copy_loop_body(set *l_n, induct_var_info *info, int unroll_factor)
+{
+  int i, opt;
+  copies_t *value, *info_op, *phi, *loop_h = NULL, key, *value_block;
+  ir_node *proj_b, *cond, *proj_1, *proj_0, *loop_head;
+  proj_b = get_irn_out(info->cmp, 0);
+  cond   = get_irn_out(proj_b, 0);
+  proj_0 = get_irn_out(cond, 0);
+  proj_1 = get_irn_out(cond, 1);
+
+  loop_head = get_loop_node(info->l_itervar_phi, 0);
+  /* I will create some nodes and need the optimization to
+     be set off.*/
+  opt = get_optimize();
+  set_optimize(0);
+
+  for (value = set_first(l_n); value != NULL; value = set_next(l_n)) {
+    if(value->irn == loop_head)
+      loop_h = value;
+    else if (is_Phi_in_loop_head(value->irn, loop_head))
+      phi = value;
+    else if (copy_loop_head){
+      if(value->irn == proj_0){
+        for (i = 0; i < unroll_factor - 1; i++)
+        /* In the copies of the loop head we replace the cmp branche with a jmp node.
+        This is just for "for" loops."do" loops are handled in function
+        new_loop_head().*/
+        value->copy[i] = new_r_Jmp(current_ir_graph, get_nodes_block(value->irn));
+      }else if(value->irn != proj_b && value->irn != cond &&
+        value->irn != proj_1)
+        /* The loop head must be copied. */
+        for (i = 0; i < unroll_factor - 1; i++){
+          copy_irn_to_irg(value->irn, current_ir_graph);
+          value->copy[i] = get_irn_link(value->irn);
+        }
+    } else {
+      /* The loop head and its nodes must not be copied. */
+      if((value->irn->op == op_Block             &&
+        value->irn != loop_head)               ||
+        (value->irn->op != op_Block             &&
+        get_nodes_block(value->irn) != loop_head)) {
+        for (i = 0; i<unroll_factor -1; i++) {
+          copy_irn_to_irg(value->irn, current_ir_graph);
+          value->copy[i] = get_irn_link(value->irn);
+        }
+      }
+    }
+  }
+
+  /* Treat the loop head block */
+  new_loop_head(l_n, info, loop_h, unroll_factor, copy_loop_head);
+  /* I have created the nodes and I set the optimization
+     to it old value.*/
+  set_optimize(opt);
+
+  /* Similarly treat the Phis in the loop head block. info->op is the node
+     along the backedges. */
+  key.irn = info->op;
+  info_op = set_find( l_n, &key, sizeof(key), HASH_PTR(key.irn));
+  assert(info_op->irn == get_Phi_pred(info->itervar_phi, info->op_pred_pos));
+  for (i = 0; i < get_irn_n_outs(loop_head); ++i) {
+    ir_node *phi = get_irn_out(loop_head, i);
+
+    if (is_Phi(phi)) {
+      copies_t *phi_pred, *phi_op;
+
+      key.irn  = get_Phi_pred(phi, info->op_pred_pos); // info->op;
+      phi_pred = set_find(l_n, &key, sizeof(key), HASH_PTR(key.irn));
+      key.irn  = phi;
+      phi_op   = set_find(l_n, &key, sizeof(key), HASH_PTR(key.irn));
+      set_Phi_copies(phi_op, phi_pred, unroll_factor);
+    }
+  }
+
+  for (value = set_first(l_n); value != NULL; value = set_next(l_n)) {
+
+    /* Set the predecessors of the copies. */
+    if (copy_loop_head){
+      set_preds(l_n, value, info, unroll_factor, NULL);
+    }else if ((value->irn->op != op_Block) && get_nodes_block(value->irn) != loop_head)
+      set_preds(l_n, value, info, unroll_factor, NULL);
+
+    if (is_Phi_in_loop_head(value->irn, loop_head) &&
+      has_backedges(value->irn))
+      /* Set the backedge of phis in the loop head. */
+      set_phi_backedge(l_n, value, info, unroll_factor);
+
+    if ((value->irn->op != op_Block) && !is_Phi_in_loop_head(value->irn, loop_head) &&
+      value->copy[0] != NULL ) {
+      ir_node *nodes_block = get_nodes_block(value->irn);
+
+      if (!copy_loop_head && nodes_block == loop_head)
+        continue;
+
+      key.irn = nodes_block;
+      value_block = set_find( l_n, &key, sizeof(key), HASH_PTR(key.irn));
+      /* Set the copy of the node in the accordant copy of its block. */
+      for(i = 0; i < unroll_factor - 1; i++){
+        set_nodes_block(value->copy[i], value_block->copy[i]);
+      }
+    }
+  }
+  /* I must repair some control flow edges, when the loop head
+     have been copied.*/
+  if (copy_loop_head && !(info->l_itervar_phi->flags & do_loop)){
+    key.irn = proj_0;
+    value   = set_find( l_n, &key, sizeof(key), HASH_PTR(key.irn));
+    key.irn = get_irn_out(proj_0, 0);
+    info_op = set_find( l_n, &key, sizeof(key), HASH_PTR(key.irn));
+    for (i = 0; i < unroll_factor - 1; i++){
+      set_Block_cfgpred(info_op->copy[i], 0, value->copy[i]);
+    }
+  }
+}
+
+/**
+ * Returns non-zero if a Proj node from the loop has a predecessor that
+ * can throw an exception.
+ *
+ * @param node  A Proj node from the loop.
+ *
+ * @return non-zero if the predecessor of the Proj node can throw an exception
+ */
+static int is_exception_possible(ir_node *node)
+{
+  ir_node *pred = get_Proj_pred(node);
+
+  /* only fragile ops can throw an exception */
+  if (! is_fragile_op(pred))
+    return 0;
+
+  /*
+   * fragile ops that are known NOT to throw
+   * an exception if their pin_state is op_pin_state_floats
+   */
+  return get_irn_pinned(pred) != op_pin_state_floats;
+}
+
+/**
+ * If a node from the loop is predecessor of the end block, then the end block must get all copies
+ * of this node as predecessors. This is possible with function calls in the unrolling loop.
+ *
+ * @param end_block          The end block.
+ * @param loop_head          The head of the unrolling loop.
+ * @param l_n                Contains all nodes of the loop.
+ * @param loop_endblock_outs The set loop_endblock_outs contains all predecessors
+ *                           of the end block from the unrolling loop.
+ * @param unroll_factor      A integer 2 <= unroll_factor <= 4.
+ */
+static void
+new_end_block(ir_node *end_block, ir_node *loop_head, set *l_n, set *loop_endblock_outs, int unroll_factor)
+{
+  copies_t key, *value;
+  int set_el, new_preds, all_new_preds, i, q;
+  int old_preds = get_Block_n_cfgpreds(end_block);   /* All old predecessors of the end block. */
+  ir_node **all_in;
+
+  for (i = 0; i < old_preds; i++) {
+    ir_node *pred = get_Block_cfgpred(end_block, i);
+     key.irn = pred;
+     value = NULL;
+     value = set_find( l_n, &key, sizeof(key), HASH_PTR(key.irn));
+
+     /* If a predecessor of the end block is a Proj from the unrolling loop (for function calls) .*/
+     if (get_irn_op(pred) == op_Proj && is_exception_possible(pred) && value != NULL &&
+	       !(!copy_loop_head && get_nodes_block(pred) == loop_head))
+       value =  set_insert(loop_endblock_outs, &key, sizeof(key), HASH_PTR(key.irn));
+  }
+
+  /* The set loop_endblock_outs contains all predecessors of the end block from the unrolling loop,
+   * set_el the amount of such nodes.
+   */
+  set_el = set_count (loop_endblock_outs);
+
+  /* If the end block haven't such predecessors, we are finished. */
+  if (!set_el) return;
+
+  new_preds = (unroll_factor - 1) * set_el;          /* All new predecessors of the end block */
+  all_new_preds = old_preds + new_preds;             /* All predecessors of this block. */
+  all_in = alloca(sizeof(*all_in) * all_new_preds);  /* A array with size for all predecessors of this block. */
+
+  for (i = 0; i < old_preds; i++)
+    all_in[i] = get_Block_cfgpred(end_block, i);    /* The old predecessors. */
+
+  value = set_first(loop_endblock_outs);
+
+  for (; value != NULL; value = set_next(loop_endblock_outs)) {
+    key.irn = value->irn;
+    value = set_find( l_n, &key, sizeof(key), HASH_PTR(key.irn));
+    for (q = 0; q < unroll_factor - 1 ; q++) {
+      all_in[i++] = value->copy[q];                 /* The new predecessors. */
+    }
+
+  }
+
+  /* Replace the old predecessors of the end block wit´h the new ones. */
+  set_irn_in(end_block, all_new_preds, all_in);
+}
+
+/** new_after_loop_block
+ *
+ * The after loop block must examine the possible exceptions in the loop.
+ * If a (Proj) node from the loop is predecessor of this block, then the
+ * after loop block must have as well all copies of this node as predecessors.
+ *
+ * @param l_n             Contains all nodes of the loop.
+ * @param block           A block after the loop.
+ * @param loop_in         A node from the loop, that is predecessor of the end block.
+ * @param unroll_factor   An integer 2 <= unroll_factor <= 4.
+ */
+static void
+new_after_loop_block (set *l_n, ir_node* block, copies_t *loop_in, int unroll_factor)
+{
+  copies_t key, *value;
+  int i, p, q, s, old_preds, new_preds, all_new_preds ;
+  ir_node **all_in;
+
+  /* The node from the unrolling loop must be a Proj. */
+  if (loop_in->irn->op != op_Proj) return;
+
+  old_preds = get_Block_n_cfgpreds(block);     /* All old predecessors of this block. */
+  new_preds = old_preds * (unroll_factor - 1); /* All new predecessors of this block. */
+  all_new_preds = old_preds + new_preds;       /* All predecessors of this block. */
+
+  all_in = alloca(sizeof(*all_in) * all_new_preds); /* An array with size for all predecessors of this block. */
+
+  for (i = 0 ; i < old_preds; i++)
+    all_in[i] = get_Block_cfgpred(block, i);      /* The old predecessors. */
+
+  q = old_preds;
+  for (i = 0; i < old_preds; i++){
+    key.irn = all_in[i];
+    value = set_find( l_n, &key, sizeof(key), HASH_PTR(key.irn));
+    p = 0;
+    for (s = 0; s < (unroll_factor - 1); s++) {
+      all_in[q++] = value->copy[p++];          /* The new predecessors. */
+    }
+  }
+  /* Replace the old predecessors of the end block whit the new one. */
+  set_irn_in(block, all_new_preds, all_in);
 }
 
+/** new_after_loop_node
+ *
+ * An after loop node (phi or call) must examine the possible exceptions in the loop.
+ * If a (Proj) node from the loop is predecessor of this node, then the after loop
+ * node must have as well all copies of this node as predecessors.
+ *
+ * @param l_n             Contains all nodes of the loop.
+ * @param loop_outs       Contains nodes after the loop,that have as predecessor a node from the loop.
+ * @param node            A node after the loop.
+ * @param loop_in         A node (Proj) from the loop, that is predecessor of *node.
+ * @param unroll_factor   An integer 2 <= unroll_factor <= 4.
+ */
+static void
+new_after_loop_node(set *l_n, set *loop_outs, ir_node *node, copies_t *loop_in, int unroll_factor)
+{
+  ir_node *pred, *block_pred = NULL, *node_block, *new_phi;
+  int phi = 0, old_preds, new_preds, all_new_preds, p, q, i, s;
+  copies_t key, *value = NULL;
+  ir_node **all_in;
+
+  old_preds = get_irn_arity(node);            /* All old predecessors of this node. */
+  new_preds =old_preds * (unroll_factor - 1); /* All new predecessors of this block. */
+  all_new_preds = old_preds + new_preds;      /* All predecessors of this block. */
+
+  all_in  = alloca(sizeof(*all_in) * all_new_preds); /* An array with size for all predecessors of this block. */
+
+  /* Verification Predecessors, successors and operation of node and loop_in.
+   * loop_in must be a Proj node.
+   */
+  if (loop_in->irn->op != op_Proj) return;
+  /* Node must be operation Phi with mode memory or a Call node. */
+  if (get_irn_op(node) == op_Phi  &&
+      get_irn_mode(node) == mode_M){
+    /* If node is a Phi node,then must have a Call node as successor. */
+    for (i = 0; i < get_irn_n_outs(node); i++)
+      if (get_irn_op(get_irn_out(node, i)) == op_Call) {
+	      phi = 1;
+        break;
+      }
+
+    if (!phi) return;
+  }
+
+  /* The predecessor of loop_in must not be a loop invariant. */
+  pred = get_Proj_pred(loop_in->irn);
+  key.irn = pred;
+  value = set_find( l_n, &key, sizeof(key), HASH_PTR(key.irn));
+  if (! value) return;
+
+  node_block = get_nodes_block(node);
+
+  /* The block of node must also have a (Proj) predecessor from the unrolling loop. */
+  for (i = 0; i < get_Block_n_cfgpreds(node_block); i++) {
+    block_pred = get_Block_cfgpred(node_block, i);
+
+    if (get_irn_op(block_pred) == op_Proj) {
+      if (get_Proj_pred(block_pred) == pred)
+	break;
+    }
+    else {
+      block_pred = NULL;
+    }
+  }
+
+  if (! block_pred) return;
 
+  key.irn = block_pred;
+  value   = set_find(l_n, &key, sizeof(key), HASH_PTR(key.irn));
 
+  if (! value)
+    return;
+  else
+    new_after_loop_block(l_n, node_block, value, unroll_factor);
 
+  for (i = 0; i < old_preds; ++i)
+    all_in[i] = get_irn_n(node, i);  /* The old predecessors. */
 
+  q = old_preds;
+  for (i = 0; i < old_preds; ++i) {
+    key.irn = all_in[i];
+    value = set_find( l_n, &key, sizeof(key), HASH_PTR(key.irn));
+    p = 0;
+    for (s = 0; s < (unroll_factor - 1); ++s) {
+      all_in[q] = value->copy[p];  /* The new predecessors. */
+      p++;
+      q++;
+    }
+  }
+  /* A new phi node with the new predecessors. */
+  new_phi = new_r_Phi(current_ir_graph, get_nodes_block(node), all_new_preds,all_in,
+		       get_irn_mode(node));
 
+  if (phi)
+    exchange(node, new_phi);
+  else{
+    for (i = 0; i < get_irn_arity(node); ++i)
+      if (get_irn_n(node, i) == pred)
+      	set_irn_n(node, i, new_phi);
+  }
+
+  /* The set loop_outs contains the visited nodes and their blocks. */
+  key.irn = node;
+  value = set_insert(loop_outs, &key, sizeof(key), HASH_PTR(key.irn));
+  key.irn = get_nodes_block(node);
+  value = set_insert(loop_outs, &key, sizeof(key), HASH_PTR(key.irn));
+}
+
+
+/* Set the outs of the unrolling loop. All loop outs of a node muss now
+ * point to the last copy of it. Just phi nodes in the loop head and proj
+ * nodes save it outs. The all copies of some Projs  have too outs.
+ *
+ * @param l_n                Contains all nodes of the loop.
+ * @param loop_outs          The set contains the visited and changed loop outs.
+ * @param loop_endblock_outs The set loop_endblock_outs contains all predecessors
+ *                           of the end block from the unrolling loop.
+ * @param info               Contains the loop information.
+ * @param unroll_factor      A integer 2 <= unroll_factor <= 4.
+ */
+static void
+set_loop_outs(set *l_n, set *loop_outs, set *loop_endblock_outs, induct_var_info *info, int unroll_factor)
+{
+  copies_t *value, key;
+  int i, p;
+  ir_node *loop_head = get_loop_node(info->l_itervar_phi, 0);
+  ir_node *end_block = get_irg_end_block(current_ir_graph);
+
+  for (value = set_first(l_n); value != NULL; value = set_next(l_n)){
+    if(get_irn_node_nr(value->irn) == 35047)
+      printf("\nHi\n");
+    if (! is_Phi_in_loop_head(value->irn, loop_head) &&
+        (get_irn_opcode(value->irn) == iro_Proj && value->copy[0] != NULL))
+      for (i = 0; i < get_irn_n_outs(value->irn); ++i) {
+        key.irn = get_irn_out(value->irn, i);
+
+        /* Search for loop outs. */
+        if (set_find( l_n, &key, sizeof(key), HASH_PTR(key.irn)) == NULL)
+          if ((key.irn->op == op_Block && get_Block_dom_depth(key.irn)  >
+               get_Block_dom_depth(loop_head))                          ||
+              (key.irn->op != op_Block && get_Block_dom_depth(get_nodes_block(key.irn)) >
+               get_Block_dom_depth(loop_head))) {
+
+	    for (p = 0; p < get_irn_arity(key.irn); p++)
+              if (value->irn == get_irn_n(key.irn, p)) {
+		if (get_irn_op(value->irn) == op_Proj && is_exception_possible(value->irn)) {
+		  if (set_find(loop_outs, &key, sizeof(key), HASH_PTR(key.irn)) == NULL) {
+		    /* If the loop out is for exceptions in the loop. */
+		    if ((get_irn_op(key.irn) == op_Phi && get_irn_mode(key.irn) == mode_M) ||
+                        get_irn_op(key.irn) == op_Call)
+		      new_after_loop_node(l_n,loop_outs, key.irn, value, unroll_factor);
+		    else
+		      continue;
+		  } else
+		    continue;
+		} else
+		  /* Loop outs in the loop head must be not changed.*/
+		  if(get_nodes_block(value->irn) != loop_head)
+		    set_irn_n(key.irn, p, value->copy[unroll_factor-2]);
+              }
+          }
+      }
+  }
+  /* This function searches for loop outs associated with function call in the unrolling loop. */
+  new_end_block (end_block, loop_head, l_n, loop_endblock_outs, unroll_factor);
+}
+
+/**
+ * Unroll the loop body with a factor that must be power of two.
+ * Called from a post walker.
+ *
+ * @param n        An IR node.
+ * @param env      points to a result
+ */
+static void do_loop_unroll(ir_node *n, void *env)
+{
+  int *unroll_done = env;
+  induct_var_info info;
+  copies_t *value;
+  set *loop_nodes, *loop_outs, *loop_endblock_outs;
+  ir_node *phi_init, *loop_head;
+  ir_node *backedge_jmp;
+  int l_sons = 0, unroll_factor = 0;
+  tarval *init, *iter_end, *iter_increment,*tarval_null, *tarval_one, *tarval_three, *tarval_two, *diff, *iter_number;
+  int backedge_pos;
+
+  copy_loop_head = 0;
+  info.itervar_phi = n;
+
+  /* The IR node must be a induction variable. */
+  if (get_irn_op(n) == op_Phi) {
+    if (is_induction_variable (&info) == NULL)
+      return;
+  }
+  else
+    return;
+
+  /* Brute force limiting of loop body size. */
+  if (get_loop_n_nodes(info.l_itervar_phi) > 2 ) return;
+
+  /* Only unroll loops that compare against a constant for exiting. */
+  if (info.cmp == NULL) return;
+
+  /* We only want to unroll innermost loops. */
+  l_sons = get_loop_n_sons(info.l_itervar_phi);
+  if ( l_sons != 0)
+    return;
+  /* "do" loops are not implementit gut for this reason
+      at the time we don't unroll them.*/
+  if(info.l_itervar_phi->flags & do_loop)
+    return;
+
+  phi_init = get_Phi_pred(info.itervar_phi, info.init_pred_pos);
+
+  if ((!(info.l_itervar_phi->flags & loop_is_count_loop))  ||
+      (info.l_itervar_phi->flags & loop_is_endless)        ||
+      (info.l_itervar_phi->flags & loop_is_dead)           ||
+      (info.l_itervar_phi->flags & once))
+    return;
+
+  init           = info.l_itervar_phi->loop_iter_start;
+  iter_end       = info.l_itervar_phi->loop_iter_end;
+  iter_increment = info.l_itervar_phi->loop_iter_increment;
+  tarval_null = get_mode_null(get_tarval_mode(iter_increment));
+  tarval_one  = get_mode_one(get_tarval_mode(init));
+
+  if(tarval_is_double(init) || tarval_is_double(iter_end) || tarval_is_double(iter_increment))
+    return;
+
+  if((tarval_is_negative(init) && tarval_is_negative(iter_end)) ||
+     (!tarval_is_negative(init) && !tarval_is_negative(iter_end)) ||
+     (tarval_is_null(init) || tarval_is_null(iter_end)))
+    diff = tarval_abs(tarval_sub(iter_end, init));
+  else
+    diff = tarval_add(tarval_abs(iter_end),tarval_abs(init));
+
+  iter_increment = tarval_abs(iter_increment);
+
+  if(!(info.l_itervar_phi->flags & do_loop))
+    diff = tarval_add(diff, tarval_one);
+  /* Test for the value of unroll factor. */
+  if (tarval_cmp(tarval_mod(diff,iter_increment), tarval_null) == pn_Cmp_Eq)
+    iter_number = tarval_div(diff, iter_increment);
+  else
+    return;
+  tarval_two = tarval_add(tarval_one, tarval_one);
+  tarval_three = tarval_add(tarval_two,tarval_one);
+
+  if (tarval_cmp(tarval_mod(iter_number, tarval_three), tarval_null) == pn_Cmp_Eq)
+    unroll_factor = 3;
+  else if (tarval_cmp(tarval_mod(iter_number, tarval_two), tarval_null) == pn_Cmp_Eq)
+    unroll_factor = 2;
+  else return;
+
+  if (get_firm_verbosity())
+    printf("\nloop unrolling with factor %d \n", unroll_factor);
+
+  /* ok, we will do unrolling */
+  *unroll_done += 1;
+
+  /* The unroll factor must be less than 4. */
+  assert(unroll_factor <= MAX_UNROLL);
+
+  loop_head = (is_natural_loop(&info)) ? get_loop_node(info.l_itervar_phi, 0) : NULL;
+
+  assert(loop_head != NULL && is_Block(loop_head));
+
+  /* We assume, the loop head has exactly one backedge.  The position of
+     the backedge is in the following variable: */
+  backedge_pos = (is_backedge(loop_head, 0)) ? 0:1;
+
+  /* A set with the nodes to copy. */
+  loop_nodes = new_set(set_cmp, 8);
+  /* A set with the loop outs for exceptions. */
+  loop_outs =  new_set(set_cmp, 8);
+
+  /* A set containing all predecessors
+     of the end block from the unrolling loop. */
+  loop_endblock_outs = new_set(set_cmp, 8);
+  /* Find all nodes of the unrolling loop. */
+  find_loop_nodes(info.itervar_phi, get_loop_node(info.l_itervar_phi, 0), loop_nodes);
+
+  /* Decide if the loop head to be copy.*/
+  copy_loop_head = loop_head_nodes(loop_nodes, &info);
+
+  /* Copy all nodes of the unrolling loop, that muss be copy. */
+  copy_loop_body(loop_nodes, &info, unroll_factor);
+
+  backedge_jmp = get_Block_cfgpred(loop_head, backedge_pos);
+
+  /* Set the backedge of the loop head. */
+  for (value = set_first(loop_nodes); value != NULL; value = set_next(loop_nodes)) {
+    if (value->irn == backedge_jmp)
+      set_Block_cfgpred(loop_head, backedge_pos, value->copy[unroll_factor-2]);
+  }
+  set_loop_outs(loop_nodes, loop_outs, loop_endblock_outs, &info, unroll_factor);
+}
 
 /* Performs loop unrolling for the passed graph. */
-void optimize_loop_unrolling(ir_graph *irg) {
+void optimize_loop_unrolling(ir_graph *irg /* unroll factor, max body size */)
+{
+  ir_graph *rem;
+  int unroll_done = 0;
+
+  if ( !get_opt_loop_unrolling()) return;
+
+  rem = current_ir_graph;
+  current_ir_graph = irg;
 
-  if (!get_optimize() || !get_opt_loop_unrolling()) return;
+  /* -- Precompute some information -- */
+
+  /* Call algorithm that computes the loop information */
+  // construct_backedges(irg);
+  compute_loop_info(irg);
+  /* Call algorithm that computes the backedges */
+  // construct_cf_backedges(irg);
+
+  /* Call algorithm that computes the dominator trees. */
+  assure_doms(irg);
+
+  /* Call algorithm that computes the out edges */
+  assure_irg_outs(irg);
+
+  collect_phiprojs(irg);
 
   /* -- Search expressions that can be optimized -- */
-  irg_walk_graph(irg, NULL, do_loop_unroll, NULL);
+  irg_walk_graph(irg, NULL, do_loop_unroll, &unroll_done);
+
+  if (unroll_done) {
+    /* unrolling was done, all info is invalid */
+    set_irg_doms_inconsistent(irg);
+    set_irg_outs_inconsistent(irg);
+    set_irg_loopinfo_state(current_ir_graph, loopinfo_cf_inconsistent);
+    set_trouts_inconsistent();
+    set_irg_callee_info_state(irg, irg_callee_info_inconsistent);
+  }
 
+  current_ir_graph = rem;
 }