remove #ifdef HAVE_CONFIG_Hs
[libfirm] / ir / opt / ifconv.c
index d53c538..63c7090 100644 (file)
 /*
- * Project:     libFIRM
- * File name:   ir/opt/ifconv.c
- * Purpose:     If conversion
- * Author:      Sebastian Hack.
- * Created:
- * CVS-ID:      $Id$
- * Copyright:   (c) 1998-2005 Universität Karlsruhe
- * Licence:     This file protected by GPL -  GNU GENERAL PUBLIC LICENSE.
+ * Copyright (C) 1995-2008 University of Karlsruhe.  All right reserved.
+ *
+ * This file is part of libFirm.
+ *
+ * This file may be distributed and/or modified under the terms of the
+ * GNU General Public License version 2 as published by the Free Software
+ * Foundation and appearing in the file LICENSE.GPL included in the
+ * packaging of this file.
+ *
+ * Licensees holding valid libFirm Professional Edition licenses may use
+ * this file in accordance with the libFirm Commercial License.
+ * Agreement provided with the Software.
+ *
+ * This file is provided AS IS with NO WARRANTY OF ANY KIND, INCLUDING THE
+ * WARRANTY OF DESIGN, MERCHANTABILITY AND FITNESS FOR A PARTICULAR
+ * PURPOSE.
  */
 
-/**
- * @file ifconv.c
- * If conversion.
- * Make Mux nodes from Conds where it its possible.
- * @author Sebastian Hack
- * @date 4.2.2005
+/*
+ * @file    ir/opt/ifconv.c
+ * @brief   If conversion
+ * @author  Christoph Mallon
+ * @version $Id$
  */
-#ifdef HAVE_CONFIG_H
-#include "config.h"
-#endif
 
-#ifdef HAVE_STDLIB_H
-#include <stdlib.h>
-#endif
-#ifdef HAVE_STRING_H
-#include <string.h>
-#endif
-#ifdef HAVE_ALLOCA_H
-#include <alloca.h>
-#endif
-#ifdef HAVE_MALLOC_H
-#include <malloc.h>
-#endif
+#include "config.h"
 
-#include "irgraph_t.h"
+#include <assert.h>
+#include "iroptimize.h"
+#include "obst.h"
 #include "irnode_t.h"
-#include "irgwalk.h"
-#include "iropt_t.h"
+#include "cdep.h"
+#include "ircons.h"
+#include "irdom.h"
 #include "irgmod.h"
-#include "irmode_t.h"
-#include "ircons_t.h"
-#include "irdom_t.h"
+#include "irgopt.h"
 #include "irgwalk.h"
+#include "irtools.h"
+#include "array_t.h"
 
-#include "ifconv.h"
-#include "irflag_t.h"
-
-#include "irprintf.h"
+// debug
+#include "irdump.h"
 #include "debug.h"
-#include "obst.h"
-#include "set.h"
-#include "bitset.h"
-#include "bitfiddle.h"
-#include "irhooks.h"
-#include "return.h"
-
-#define MAX_DEPTH   4
-
-/**
- * check, if a node is const and return its tarval or
- * return a default tarval.
- * @param cnst The node whose tarval to get.
- * @param or The alternative tarval, if the node is no Const.
- * @return The tarval of @p cnst, if the node is Const, @p otherwise.
- */
-static tarval *get_value_or(ir_node *cnst, tarval *or)
-{
-  return get_irn_op(cnst) == op_Const ? get_Const_tarval(cnst) : or;
-}
-
-
-/**
- * Try to optimize nested muxes into a dis- or conjunction
- * of two muxes.
- * @param mux The parent mux, which has muxes as operands.
- * @return The replacement node for this mux. If the optimization is
- * successful, this might be an And or Or node, if not, its the mux
- * himself.
- */
-static ir_node *optimize_mux_chain(ir_node *mux)
-{
-  int i;
-  ir_node *res;
-  ir_node *ops[2];
-  ir_mode *mode = get_irn_mode(mux);
-  tarval *null;
-  tarval *minus_one;
-
-  /*
-   * If we have no mux, or its mode is not integer, we
-   * can return.
-   */
-  if(get_irn_op(mux) != op_Mux || !mode_is_int(mode))
-    return mux;
-
-  res = mux;
-  null = get_mode_null(mode);
-  minus_one = tarval_sub(null, get_tarval_one(mode));
-
-  ops[0] = get_Mux_false(mux);
-  ops[1] = get_Mux_true(mux);
-
-  for(i = 0; i < 2; ++i) {
-    ir_node *a, *b, *d;
-    tarval *tva, *tvb, *tvd;
-    ir_node *child_mux;
-
-    /*
-     * A mux operand at the first position can be factored
-     * out, if the operands fulfill several conditions:
-     *
-     * mux(c1, mux(c2, a, b), d)
-     *
-     * This can be made into:
-     * 1) mux(c1, 0, d) | mux(c2, a, b)
-     *    if a | d == d and b | d == d
-     *
-     * 2) mux(c1, -1, d) & mux(c2, a, b)
-     *    if a & d == d and a & b == b
-     */
-    if(get_irn_op(ops[i]) == op_Mux) {
-
-      child_mux = ops[i];
-      a = get_Mux_false(child_mux);
-      b = get_Mux_true(child_mux);
-      d = ops[1 - i];
-
-      /* Try the or stuff */
-      tva = get_value_or(a, minus_one);
-      tvb = get_value_or(b, minus_one);
-      tvd = get_value_or(d, null);
-
-      if(tarval_cmp(tarval_or(tva, tvd), tvd) == pn_Cmp_Eq
-          && tarval_cmp(tarval_or(tvb, tvd), tvd) == pn_Cmp_Eq) {
-
-        ops[i] = new_Const(mode, null);
-        res = new_r_Or(current_ir_graph, get_nodes_block(mux),
-            mux, child_mux, mode);
-        break;
-      }
-
-      /* If the or didn't go, try the and stuff */
-      tva = get_value_or(a, null);
-      tvb = get_value_or(b, null);
-      tvd = get_value_or(d, minus_one);
-
-      if(tarval_cmp(tarval_and(tva, tvd), tvd) == pn_Cmp_Eq
-          && tarval_cmp(tarval_and(tvb, tvd), tvd) == pn_Cmp_Eq) {
-
-        ops[i] = new_Const(mode, minus_one);
-        res = new_r_And(current_ir_graph, get_nodes_block(mux),
-            mux, child_mux, mode);
-        break;
-      }
-    }
-  }
-
-  /* recursively optimize nested muxes. */
-  set_irn_n(mux, 1, optimize_mux_chain(ops[0]));
-  set_irn_n(mux, 2, optimize_mux_chain(ops[1]));
-
-  return res;
-}
 
-
-/***********************************************************
- * The If conversion itself.
- ***********************************************************/
+DEBUG_ONLY(static firm_dbg_module_t *dbg);
 
 /** allow every Mux to be created. */
-static int default_allow_mux(ir_node *sel, ir_node *false_res, ir_node *true_res) {
-  return 1;
+static int default_allow_ifconv(ir_node *sel, ir_node* phi_list, int i, int j)
+{
+       (void) sel;
+       (void) phi_list;
+       (void) i;
+       (void) j;
+       return 1;
 }
 
 /**
  * Default options.
  */
-static const opt_if_conv_info_t default_info = {
-  MAX_DEPTH,
-  default_allow_mux
+static const ir_settings_if_conv_t default_info = {
+       0,    /* doesn't matter for Mux */
+       default_allow_ifconv
 };
 
-/** The debugging module. */
-static firm_dbg_module_t *dbg;
-
 /**
- * A simple check for side effects upto an opcode of a ir node.
- * @param irn The ir node to check,
- * @return 1 if the opcode itself may produce side effects, 0 if not.
+ * Returns non-zero if a Block can be emptied.
  */
-static INLINE int has_side_effects(const ir_node *irn)
-{
-  ir_op *op = get_irn_op(irn);
-
-  if (op == op_Cmp)
-    return 0;
-
-  return !mode_is_datab(get_irn_mode(irn));
+static int can_empty_block(ir_node *block) {
+       return get_Block_mark(block) == 0;
 }
 
-/**
- * Possible failure reasons
- */
-enum failure_reason_t {
-  SUCCESS      = IF_RESULT_SUCCESS,
-  TO_DEEP      = IF_RESULT_TOO_DEEP,
-  SIDE_EFFECTS = IF_RESULT_SIDE_EFFECT,
-  PHI_FOUND    = IF_RESULT_SIDE_EFFECT_PHI,
-  DENIED       = IF_RESULT_DENIED
-};
 
-/**
- * Decides, if a given expression and its subexpressions
- * (to certain, also given extent) can be moved to a block.
- *
- * @param expr      The expression to examine.
- * @param block     The block where the expression should go.
- * @param depth     The current depth, passed recursively. Use 0 for
- *                  non-recursive calls.
- * @param info      The options for createing Mux nodes.
- * examined.
- *
- * @return a failure reason
- */
-static int _can_move_to(ir_node *expr, ir_node *dest_block, int depth, const opt_if_conv_info_t *info)
+static ir_node* walk_to_projx(ir_node* start, const ir_node* dependency)
 {
-  int i, n;
-  int res = SUCCESS;
-  ir_node *expr_block = get_nodes_block(expr);
-
-  /*
-   * If we are forced to look too deep into the expression,
-   * treat it like it could not be moved.
-   */
-  if(depth >= info->max_depth) {
-    res = TO_DEEP;
-    goto end;
-  }
-
-  /*
-   * If the block of the expression dominates the specified
-   * destination block, it does not matter if the expression
-   * has side effects or anything else. It is executed on each
-   * path the destination block is reached.
-   */
-  if (block_dominates(expr_block, dest_block))
-    goto end;
-
-  /*
-   * We cannot move phis!
-   */
-  if (is_Phi(expr)) {
-    res = PHI_FOUND;
-    goto end;
-  }
-
-  /*
-   * This should be superfluous and could be converted into a assertion.
-   * The destination block _must_ dominate the block of the expression,
-   * else the expression could be used without its definition.
-   */
-  if (! block_dominates(dest_block, expr_block)) {
-    res = IF_RESULT_SIDE_EFFECT;
-    goto end;
-  }
-
-  /*
-   * Surely, if the expression does not have a data mode, it is not
-   * movable. Perhaps one should also test the floating property of
-   * the opcode/node.
-   */
-  if (has_side_effects(expr)) {
-    res = IF_RESULT_SIDE_EFFECT;
-    goto end;
-  }
-
-  /*
-   * If the node looks alright so far, look at its operands and
-   * check them out. If one of them cannot be moved, this one
-   * cannot be moved either.
-   */
-  for (i = 0, n = get_irn_arity(expr); i < n; ++i) {
-    ir_node *op = get_irn_n(expr, i);
-    int new_depth = is_Proj(op) ? depth : depth + 1;
-
-    res = _can_move_to(op, dest_block, new_depth, info);
-
-    if (res != SUCCESS)
-      goto end;
-  }
-
-end:
-  DBG((dbg, LEVEL_3, "\t\t\tcan move to %n: %d\n", expr, res));
-
-  return res;
+       int arity;
+       int i;
+
+       /* No need to find the conditional block if this block cannot be emptied and
+        * therefore not moved */
+       if (!can_empty_block(start)) return NULL;
+
+       arity = get_irn_arity(start);
+       for (i = 0; i < arity; ++i) {
+               ir_node* pred = get_irn_n(start, i);
+               ir_node* pred_block = get_nodes_block(pred);
+
+               if (pred_block == dependency) {
+                       if (is_Proj(pred)) {
+                               assert(get_irn_mode(pred) == mode_X);
+                               return pred;
+                       }
+                       return NULL;
+               }
+
+               if (is_Proj(pred)) {
+                       assert(get_irn_mode(pred) == mode_X);
+                       return NULL;
+               }
+
+               if (is_cdep_on(pred_block, dependency)) {
+                       return walk_to_projx(pred_block, dependency);
+               }
+       }
+       return NULL;
 }
 
-/**
- * Convenience function for _can_move_to.
- * Checks, if an expression can be moved to another block. The check can
- * be limited to a expression depth meaning if we need to crawl in
- * deeper into an expression than a given threshold to examine if
- * it can be moved, the expression is rejected and the test returns
- * false.
- *
- * @param expr       The expression to check for.
- * @param dest_block The destination block you want @p expr to be.
- * @param info       The options for createing Mux nodes.
- *
- * @return return a failure reason
- */
-static INLINE int can_move_to(ir_node *expr, ir_node *dest_block, const opt_if_conv_info_t *info)
-{
-  return _can_move_to(expr, dest_block, 0, info);
-}
 
 /**
- * move a DAG given by a root node expr into a new block
- *
- * @param expr       the root of a dag
- * @param dest_block the destination block
+ * Copies the DAG starting at node to the ith predecessor block of src_block
+ * -if the node isn't in the src_block, this is a nop and the node is returned
+ * -if the node is a phi in the src_block, the ith predecessor of the phi is
+ *   returned
+ * otherwise returns the copy of the passed node
  */
-static void move_to(ir_node *expr, ir_node *dest_block)
+static ir_node* copy_to(ir_node* node, ir_node* src_block, int i)
 {
-  int i, n;
-  ir_node *expr_block = get_nodes_block(expr);
-
-  /*
-   * If we reached the dominator, we are done.
-   * We will never put code through the dominator
-   */
-  if (block_dominates(expr_block, dest_block))
-    return;
-
-  for (i = 0, n = get_irn_arity(expr); i < n; ++i)
-    move_to(get_irn_n(expr, i), dest_block);
-
-  set_nodes_block(expr, dest_block);
+       ir_node* dst_block;
+       ir_node* copy;
+       int arity;
+       int j;
+
+       if (get_nodes_block(node) != src_block) return node;
+       if (get_irn_op(node) == op_Phi) return get_irn_n(node, i);
+
+       copy = exact_copy(node);
+       dst_block = get_nodes_block(get_irn_n(src_block, i));
+       set_nodes_block(copy, dst_block);
+
+       DB((dbg, LEVEL_1, "Copying node %+F to block %+F, copy is %+F\n",
+               node, dst_block, copy));
+
+       arity = get_irn_arity(node);
+       for (j = 0; j < arity; ++j) {
+               set_irn_n(copy, j, copy_to(get_irn_n(node, j), src_block, i));
+               DB((dbg, LEVEL_2, "-- pred %d is %+F\n", j, get_irn_n(copy, j)));
+       }
+       return copy;
 }
 
-/**
- * return the common dominator of two blocks
- */
-static INLINE ir_node *common_idom(ir_node *b1, ir_node *b2)
-{
-  if(block_dominates(b1, b2))
-    return b1;
-  else if(block_dominates(b2, b1))
-    return b2;
-  else {
-    ir_node *p;
-
-    for (p = get_Block_idom(b1); !block_dominates(p, b2); p = get_Block_idom(p));
-    return p;
-  }
-}
 
 /**
- * Information about a cond node.
+ * Remove predecessors i and j from node and add predecessor new_pred
  */
-typedef struct _cond_t {
-  ir_node *cond;          /**< The cond node. */
-  struct list_head list;  /**< List head which is used for queuing this cond
-                               into the cond bunch it belongs to. */
-  unsigned is_new : 1;
-  unsigned totally_covers : 1;
-  struct _cond_t *link;
-  long visited_nr;
-
-  /**
-   * Information about the both 'branches'
-   * (true and false), the cond creates.
-   */
-  struct {
-    int pos;         /**< Number of the predecessor of the
-                          phi block by which this branch is
-                          reached. It is -1, if this branch is
-                          only reached through another cond. */
-
-    struct _cond_t *masked_by; /**< If this cond's branch is only reached
-                                    through another cond, we store this
-                                    cond ir_node here. */
-  } cases[2];
-} cond_t;
-
-/**
- * retrieve the conditional information from a Cond node
- */
-static INLINE cond_t *get_cond(ir_node *irn, set *cond_set)
+static void rewire(ir_node* node, int i, int j, ir_node* new_pred)
 {
-  cond_t templ;
-
-  templ.cond = irn;
-  return set_find(cond_set, &templ, sizeof(templ), HASH_PTR(templ.cond));
+       int arity = get_irn_arity(node);
+       ir_node **ins;
+       int k;
+       int l;
+
+       NEW_ARR_A(ir_node *, ins, arity - 1);
+
+       l = 0;
+       for (k = 0; k < i;     ++k) ins[l++] = get_irn_n(node, k);
+       for (++k;   k < j;     ++k) ins[l++] = get_irn_n(node, k);
+       for (++k;   k < arity; ++k) ins[l++] = get_irn_n(node, k);
+       ins[l++] = new_pred;
+       assert(l == arity - 1);
+       set_irn_in(node, l, ins);
 }
 
 
-typedef void (cond_walker_t)(cond_t *cond, void *env);
-
-static void _walk_conds(cond_t *cond, cond_walker_t *pre, cond_walker_t *post,
-      long visited_nr, void *env)
-{
-  int i;
-
-  if(cond->visited_nr >= visited_nr)
-    return;
-
-  cond->visited_nr = visited_nr;
-
-  if(pre)
-    pre(cond, env);
-
-  for(i = 0; i < 2; ++i) {
-    cond_t *c = cond->cases[i].masked_by;
-
-    if(c)
-      _walk_conds(c, pre, post, visited_nr, env);
-  }
-
-  if(post)
-    post(cond, env);
-}
-
-static long cond_visited_nr = 0;
-
-static void walk_conds(cond_t *cond, cond_walker_t *pre, cond_walker_t *post, void *env)
-{
-  _walk_conds(cond, pre, post, ++cond_visited_nr, env);
-}
-
-static void link_conds(cond_t *cond, void *env)
-{
-  cond_t **ptr = (cond_t **) env;
-
-  cond->link = *ptr;
-  *ptr = cond;
-}
-
 /**
- * Compare two conds for use in a firm set.
- * Two cond_t's are equal, if they designate the same cond node.
- * @param a A cond_t.
- * @param b Another one.
- * @param size Not used.
- * @return 0 (!) if they are equal, != 0 otherwise.
+ * Remove the jth predecessors from the ith predecessor of block and add it to block
  */
-static int cond_cmp(const void *a, const void *b, size_t size)
+static void split_block(ir_node* block, int i, int j)
 {
-  const cond_t *x = a;
-  const cond_t *y = b;
-  return x->cond != y->cond;
+       ir_node* pred_block = get_nodes_block(get_irn_n(block, i));
+       int arity = get_irn_arity(block);
+       int new_pred_arity;
+       ir_node *phi, *next;
+       ir_node **ins;
+       ir_node **pred_ins;
+       int k;
+
+       DB((dbg, LEVEL_1, "Splitting predecessor %d of predecessor %d of %+F\n", j, i, block));
+
+       NEW_ARR_A(ir_node*, ins, arity + 1);
+
+       for (phi = get_Block_phis(block); phi != NULL; phi = get_Phi_next(phi)) {
+               ir_node* copy = copy_to(get_irn_n(phi, i), pred_block, j);
+
+               for (k = 0; k < i; ++k) ins[k] = get_irn_n(phi, k);
+               ins[k++] = copy;
+               for (; k < arity; ++k) ins[k] = get_irn_n(phi, k);
+               ins[k] = get_irn_n(phi, i);
+               assert(k == arity);
+               set_irn_in(phi, arity + 1, ins);
+       }
+
+       for (k = 0; k < i; ++k) ins[k] = get_irn_n(block, k);
+       ins[k++] = get_irn_n(pred_block, j);
+       for (; k < arity; ++k) ins[k] = get_irn_n(block, k);
+       ins[k] = get_irn_n(block, i);
+       assert(k == arity);
+       set_irn_in(block, arity + 1, ins);
+
+       new_pred_arity = get_irn_arity(pred_block) - 1;
+       NEW_ARR_A(ir_node*, pred_ins, new_pred_arity);
+
+       for (phi = get_Block_phis(pred_block); phi != NULL; phi = next) {
+               for (k = 0; k < j; ++k) pred_ins[k] = get_irn_n(phi, k);
+               for (; k < new_pred_arity; ++k) pred_ins[k] = get_irn_n(phi, k + 1);
+               assert(k == new_pred_arity);
+               next = get_Phi_next(phi);
+               if (new_pred_arity > 1) {
+                       set_irn_in(phi, new_pred_arity, pred_ins);
+               } else {
+                       exchange(phi, pred_ins[0]);
+               }
+       }
+
+       for (k = 0; k < j; ++k) pred_ins[k] = get_irn_n(pred_block, k);
+       for (; k < new_pred_arity; ++k) pred_ins[k] = get_irn_n(pred_block, k + 1);
+       assert(k == new_pred_arity);
+       if (new_pred_arity > 1) {
+               set_irn_in(pred_block, new_pred_arity, pred_ins);
+       } else {
+               exchange(pred_block, get_nodes_block(pred_ins[0]));
+       }
 }
 
-/**
- * Information about conds which can be made to muxes.
- * Instances of this struct are attached to the link field of
- * blocks in which phis are located.
- */
-typedef struct _cond_info_t {
-  struct list_head list;      /**< Used to list all of these structs per class. */
-
-  struct list_head roots;     /**< A list of non-depending Conds. Two Conds are
-                                independent, if it's not possible not reach one from the
-                                other (all Conds in this list have to dominate the
-                                block this struct is attached to). */
 
-  ir_node *first_phi;         /**< The first phi node this cond info was made for. */
-  set *cond_set;              /**< A set of all dominating reachable Conds. */
-} cond_info_t;
-
-/**
- * @see find_conds.
- */
-static void _find_conds(ir_node *irn, unsigned long visited_nr,
-    ir_node *dominator, cond_t *masked_by, int pos, int depth, cond_info_t *ci)
+static void prepare_path(ir_node* block, int i, const ir_node* dependency)
 {
-  ir_node *block;
-  int saw_select_cond = 0;
-
-  block = get_nodes_block(irn);
-
-  /*
-   * Only check this block if it is dominated by the specified
-   * dominator or it has not been visited yet.
-   */
-  if (block_dominates(dominator, block) && get_Block_block_visited(block) < visited_nr) {
-    cond_t *res = masked_by;
-    int i, n;
-
-    /* check, if we're on a ProjX
-     *
-     * Further, the ProjX/Cond block must dominate the base block
-     * (the block with the phi in it), otherwise, the Cond
-     * is not affecting the phi so that a mux can be inserted.
-     */
-    if(is_Proj(irn) && get_irn_mode(irn) == mode_X) {
-
-      int proj = get_Proj_proj(irn);
-      ir_node *cond = get_Proj_pred(irn);
-
-      /* true, if the mode is a mode_b cond _NO_ switch cond */
-      int is_modeb_cond = get_irn_opcode(cond) == iro_Cond
-        && get_irn_mode(get_Cond_selector(cond)) == mode_b;
-
-      saw_select_cond = !is_modeb_cond;
-
-      /* Check, if the pred of the proj is a Cond
-       * with a Projb as selector.
-       */
-      if(is_modeb_cond) {
-        cond_t c;
-
-        memset(&c, 0, sizeof(c));
-        c.cond = cond;
-        c.is_new = 1;
-        c.cases[0].pos = -1;
-        c.cases[1].pos = -1;
-
-        /* get or insert the cond info into the set. */
-        res = set_insert(ci->cond_set, &c, sizeof(c), HASH_PTR(cond));
-
-        /*
-         * If this cond is already masked by the masked_by cond
-         * return immediately, since we don't have anything to add.
-         */
-        if(masked_by && res->cases[proj].masked_by == masked_by)
-          return;
-
-        if(res->is_new) {
-          res->is_new = 0;
-          list_add(&res->list, &ci->roots);
-        }
-
-        /*
-         * Set masked by (either NULL or another cond node.
-         * If this cond is truly masked by another one, set
-         * the position of the actually investigated branch
-         * to -1. Since the cond is masked by another one,
-         * there could be more ways from the start block
-         * to this branch, so we choose -1.
-         */
-        res->cases[proj].masked_by = masked_by;
-
-        if(!masked_by)
-          res->cases[proj].pos = pos;
-
-        /*
-         * Since the masked_by nodes masks a cond, remove it from the
-         * root list of the conf trees.
-         */
-        else {
-          assert(res->cases[proj].pos < 0);
-          list_del_init(&masked_by->list);
-        }
-
-        DBG((dbg, LEVEL_2, "%n (%s branch) "
-              "for pos %d in block %n reached by %n\n",
-              cond, proj ? "true" : "false", pos,
-              block, masked_by ? masked_by->cond : NULL));
-      }
-    }
-
-    if(get_Block_block_visited(block) < visited_nr && !saw_select_cond) {
-
-      set_Block_block_visited(block, visited_nr);
-
-      /* Search recursively from this cond. */
-      for(i = 0, n = get_irn_arity(block); i < n; ++i) {
-        ir_node *pred = get_irn_n(block, i);
-
-        /*
-         * If the depth is 0 (the first recursion), we set the pos to
-         * the current viewed predecessor, else we adopt the position
-         * as given by the caller. We also increase the depth for the
-         * recursively called functions.
-         */
-        _find_conds(pred, visited_nr, dominator, res, pos, depth + (res != masked_by), ci);
-      }
-    }
-  }
+       ir_node* pred = get_nodes_block(get_irn_n(block, i));
+       int pred_arity;
+       int j;
+
+       DB((dbg, LEVEL_1, "Preparing predecessor %d of %+F\n", i, block));
+
+       pred_arity = get_irn_arity(pred);
+       for (j = 0; j < pred_arity; ++j) {
+               ir_node* pred_pred = get_nodes_block(get_irn_n(pred, j));
+
+               if (is_cdep_on(pred_pred, dependency)) {
+                       prepare_path(pred, j, dependency);
+                       split_block(block, i, j);
+                       break;
+               }
+       }
 }
 
 
-/**
- * A convenience function for _find_conds.
- * It sets some parameters needed for recursion to appropriate start
- * values. Always use this function.
- *
- * @param irn   The node to start looking for Conds from. This might
- *              be the phi node we are investigating.
- * @param conds The set to record the found Conds in.
- */
-static INLINE void find_conds(ir_node *irn, cond_info_t *ci)
+static void if_conv_walker(ir_node* block, void* env)
 {
-  int i, n;
-  unsigned long visited_nr;
-  ir_node *block = get_nodes_block(irn);
-  ir_node *dom = get_Block_idom(block);
-
-  for(i = 0, n = get_irn_arity(block); i < n; ++i) {
-    ir_node *pred = get_irn_n(block, i);
-
-    inc_irg_block_visited(current_ir_graph);
-    visited_nr = get_irg_block_visited(current_ir_graph);
-    set_Block_block_visited(block, visited_nr);
-
-    DBG((dbg, LEVEL_2, "find conds at pred %d (%n) and idom %n\n", i, pred, dom));
-    _find_conds(pred, visited_nr, dom, NULL, i, 0, ci);
-  }
+       ir_settings_if_conv_t* opt_info = env;
+       int arity;
+       int i;
+
+       /* Bail out, if there are no Phis at all */
+       if (get_Block_phis(block) == NULL) return;
+
+restart:
+       arity = get_irn_arity(block);
+       for (i = 0; i < arity; ++i) {
+               ir_node* pred0;
+               ir_cdep* cdep;
+
+               pred0 = get_Block_cfgpred_block(block, i);
+               for (cdep = find_cdep(pred0); cdep != NULL; cdep = cdep->next) {
+                       const ir_node* dependency = cdep->node;
+                       ir_node* projx0 = walk_to_projx(pred0, dependency);
+                       ir_node* cond;
+                       int j;
+
+                       if (projx0 == NULL) continue;
+
+                       cond = get_Proj_pred(projx0);
+                       if (! is_Cond(cond))
+                               continue;
+
+                       /* We only handle boolean decisions, no switches */
+                       if (get_irn_mode(get_Cond_selector(cond)) != mode_b) continue;
+
+                       for (j = i + 1; j < arity; ++j) {
+                               ir_node* projx1;
+                               ir_node* sel;
+                               ir_node* mux_block;
+                               ir_node* phi;
+                               ir_node* pred1;
+                               dbg_info* cond_dbg;
+
+                               pred1 = get_Block_cfgpred_block(block, j);
+
+                               if (!is_cdep_on(pred1, dependency)) continue;
+
+                               projx1 = walk_to_projx(pred1, dependency);
+
+                               if (projx1 == NULL) continue;
+
+                               phi = get_Block_phis(block);
+                               if (!opt_info->allow_ifconv(get_Cond_selector(cond), phi, i, j)) continue;
+
+                               DB((dbg, LEVEL_1, "Found Cond %+F with proj %+F and %+F\n",
+                                       cond, projx0, projx1
+                               ));
+
+                               prepare_path(block, i, dependency);
+                               prepare_path(block, j, dependency);
+                               arity = get_irn_arity(block);
+
+                               sel = get_Cond_selector(cond);
+
+                               mux_block = get_nodes_block(cond);
+                               cond_dbg = get_irn_dbg_info(cond);
+                               do {
+                                       ir_node* val_i = get_irn_n(phi, i);
+                                       ir_node* val_j = get_irn_n(phi, j);
+                                       ir_node* mux;
+                                       ir_node* next_phi;
+
+                                       if (val_i == val_j) {
+                                               mux = val_i;
+                                               DB((dbg, LEVEL_2,  "Generating no Mux, because both values are equal\n"));
+                                       } else {
+                                               ir_node *t, *f;
+
+                                               /* Something is very fishy if two predecessors of a PhiM point into
+                                                * one block, but not at the same memory node
+                                                */
+                                               assert(get_irn_mode(phi) != mode_M);
+                                               if (get_Proj_proj(projx0) == pn_Cond_true) {
+                                                       t = val_i;
+                                                       f = val_j;
+                                               } else {
+                                                       t = val_j;
+                                                       f = val_i;
+                                               }
+
+                                               mux = new_rd_Mux(cond_dbg, current_ir_graph, mux_block, sel, f, t, get_irn_mode(phi));
+                                               DB((dbg, LEVEL_2, "Generating %+F for %+F\n", mux, phi));
+                                       }
+
+                                       next_phi = get_Phi_next(phi);
+
+                                       if (arity == 2) {
+                                               exchange(phi, mux);
+                                       } else {
+                                               rewire(phi, i, j, mux);
+                                       }
+
+                                       phi = next_phi;
+                               } while (phi != NULL);
+
+                               exchange(get_nodes_block(get_irn_n(block, i)), mux_block);
+                               exchange(get_nodes_block(get_irn_n(block, j)), mux_block);
+
+                               if (arity == 2) {
+                                       unsigned mark;
+#if 1
+                                       DB((dbg, LEVEL_1,  "Welding block %+F and %+F\n", block, mux_block));
+                                       /* copy the block-info from the Mux-block to the block before merging */
+
+                                       mark =  get_Block_mark(mux_block) | get_Block_mark(block);
+                                       set_Block_mark(block, mark);
+                                       set_Block_phis(block, get_Block_phis(mux_block));
+
+                                       set_irn_in(block, get_irn_arity(mux_block), get_irn_in(mux_block) + 1);
+                                       exchange_cdep(mux_block, block);
+                                       exchange(mux_block, block);
+#else
+                                       DB((dbg, LEVEL_1,  "Welding block %+F to %+F\n", block, mux_block));
+                                       mark =  get_Block_mark(mux_block) | get_Block_mark(block);
+                                       /* mark both block just to be sure, should be enough to mark mux_block */
+                                       set_Block_mark(mux_block, mark);
+                                       exchange(block, mux_block);
+#endif
+                                       return;
+                               } else {
+                                       rewire(block, i, j, new_r_Jmp(current_ir_graph, mux_block));
+                                       goto restart;
+                               }
+                       }
+               }
+       }
 }
 
 /**
- * Make the mux for a given cond.
- *
- * @param phi       The phi node which shall be replaced by a mux.
- * @param dom       The block where the muxes shall be placed.
- * @param cond      The cond information.
- * @param info      The options for createing Mux nodes.
- * @return The mux node made for this cond.
+ * Block walker: clear block mark and Phi list
  */
-static ir_node *make_mux_on_demand(ir_node *phi, ir_node *dom, cond_t *cond,
-    const opt_if_conv_info_t *info, ir_node **mux, bitset_t *positions,
-    int *muxes_made, long visited_nr)
+static void init_block_link(ir_node *block, void *env)
 {
-  int i, can_move[2];
-  ir_node *projb = get_Cond_selector(cond->cond);
-  ir_node *bl = get_nodes_block(cond->cond);
-  ir_node *operands[2];
-  int set[2];
-
-  cond->visited_nr = visited_nr;
-  DBG((dbg, LEVEL_2, "%n\n", cond->cond));
-  for(i = 0; i < 2; ++i) {
-    cond_t *masked_by = cond->cases[i].masked_by;
-    int pos = cond->cases[i].pos;
-
-    operands[i] = NULL;
-    set[i] = -1;
-
-    /*
-     * If this Cond branch is masked by another cond, make the mux
-     * for that Cond first, since the Mux for this cond takes
-     * it as an operand.
-     */
-    if(masked_by) {
-      assert(pos < 0);
-      DBG((dbg, LEVEL_2, "\tmasked by: %n\n", masked_by->cond));
-      if(masked_by->visited_nr < visited_nr)
-        operands[i] = make_mux_on_demand(phi, dom, masked_by, info, mux, positions, muxes_made, visited_nr);
-    }
-
-    /*
-     * If this cond branch is not masked by another cond, take
-     * the corresponding phi operand as an operand to the mux.
-     */
-    else if(pos >= 0) {
-      operands[i] = get_irn_n(phi, pos);
-      set[i] = pos;
-    }
-  }
-
-  /*
-   * Move the operands to the dominator block if the cond
-   * made sense. Some Conds found are not suitable for making a mux
-   * out of them, since one of their branches cannot be reached from
-   * the phi block. In that case we do not make a mux and return NULL.
-   */
-  if(operands[0] && operands[1]) {
-    if (operands[0] == operands[1]) {
-      /* there is no gain in using mux in this case, as
-         it will be optimized away. We will NOT move the
-         content of the blocks either
-        */
-      for (i = 0; i < 2; ++i)
-        if(set[i] >= 0)
-          bitset_set(positions, set[i]);
-
-      *mux = operands[0];
-      return *mux;
-    }
-
-    can_move[0] = can_move_to(operands[0], bl, info);
-    can_move[1] = can_move_to(operands[1], bl, info);
-
-    if (can_move[0] == SUCCESS && can_move[1] == SUCCESS) {
-      if (info->allow_mux(projb, operands[0], operands[1])) {
-        move_to(operands[0], bl);
-        move_to(operands[1], bl);
-
-        /* Make the mux. */
-        *mux = new_r_Mux(current_ir_graph, bl, projb,
-            operands[0], operands[1], get_irn_mode(operands[0]));
-
-        *muxes_made += 1;
-
-        DBG((dbg, LEVEL_2, "\t%n(%n, %n, %n)[%d, %d]\n",
-              *mux, projb, operands[0], operands[1], set[0], set[1]));
-
-        for(i = 0; i < 2; ++i)
-          if(set[i] >= 0) {
-            bitset_set(positions, set[i]);
-
-            /* we have done one */
-            hook_if_conversion(current_ir_graph, phi, set[i], *mux, IF_RESULT_SUCCESS);
-          }
-      }
-      else {
-        hook_if_conversion(current_ir_graph, phi, set[i], *mux, IF_RESULT_DENIED);
-      }
-    }
-    else {
-      if(can_move[0] != SUCCESS)
-        hook_if_conversion(current_ir_graph, phi, set[0], NULL, can_move[0]);
-      if(can_move[1] != SUCCESS)
-        hook_if_conversion(current_ir_graph, phi, set[1], NULL, can_move[1]);
-    }
-  }
-  else {
-    if(operands[0])
-      hook_if_conversion(current_ir_graph, phi, set[0], NULL, IF_RESULT_BAD_CF);
-    if(operands[1])
-      hook_if_conversion(current_ir_graph, phi, set[1], NULL, IF_RESULT_BAD_CF);
-  }
-
-  return *mux;
+       (void)env;
+       set_Block_mark(block, 0);
+       set_Block_phis(block, NULL);
 }
 
-typedef struct _phi_info_t {
-  struct list_head list;
-  cond_info_t *cond_info;
-  ir_node *irn;
-} phi_info_t;
-
 
 /**
- * Examine a phi node if it can be replaced by some muxes.
- * @param irn A phi node.
- * @param info Parameters for the if conversion algorithm.
+ * Daisy-chain all phis in a block
+ * If a non-movable node is encountered set the has_pinned flag in its block.
  */
-static int check_out_phi(phi_info_t *phi_info, const opt_if_conv_info_t *info)
-{
-  ir_node *irn = phi_info->irn;
-  ir_node *block, *nw;
-  cond_info_t *cond_info = phi_info->cond_info;
-  cond_t *cond;
-  int i, arity;
-  int muxes_made = 0;
-  bitset_t *positions;
-
-  block = get_nodes_block(irn);
-  arity = get_irn_arity(irn);
-  positions = bitset_alloca(arity);
-
-  assert(is_Phi(irn));
-  assert(get_irn_arity(irn) == get_irn_arity(block));
-  assert(arity > 0);
-
-  DBG((dbg, LEVEL_2, "phi candidate: %n\n", irn));
-
-  list_for_each_entry(cond_t, cond, &cond_info->roots, list) {
-    ir_node *cidom = block;
-    ir_node *mux = NULL;
-    cond_t *p, *head = NULL;
-    long pos;
-
-    bitset_clear_all(positions);
-
-    DBG((dbg, LEVEL_2, "\tcond root: %n\n", cond->cond));
-    /*
-     * Link all conds which are in the subtree of
-     * the current cond in the list together.
-     */
-    walk_conds(cond, link_conds, NULL, &head);
-
-    cidom = block;
-    for(p = head; p; p = p->link) {
-      for(i = 0; i < 2; ++i) {
-        int pos = p->cases[i].pos;
-        if(pos != -1)
-          cidom = common_idom(cidom, get_nodes_block(get_irn_n(block, pos)));
-      }
-    }
-
-    DBG((dbg, LEVEL_2, "\tcommon idom: %n\n", cidom));
-    make_mux_on_demand(irn, cidom, cond, info, &mux, positions, &muxes_made, ++cond_visited_nr);
-
-    if(mux) {
-      bitset_foreach(positions, pos)
-        set_irn_n(irn, (int) pos, mux);
-    }
-  }
-
-  /*
-   * optimize the phi away. This can anable further runs of this
-   * function. Look at _can_move. phis cannot be moved there.
-   */
-  nw = optimize_in_place_2(irn);
-  if(nw != irn)
-    exchange(irn, nw);
-
-  return muxes_made;
+static void collect_phis(ir_node *node, void *env) {
+       (void) env;
+
+       if (is_Phi(node)) {
+               ir_node *block = get_nodes_block(node);
+
+               add_Block_phi(block, node);
+       } else {
+               if (is_no_Block(node) && get_irn_pinned(node) == op_pin_state_pinned) {
+                       /*
+                        * Ignore control flow nodes, these will be removed.
+                        * This ignores Raise. That is surely bad. FIXME.
+                        */
+                       if (!is_cfop(node)) {
+                               ir_node *block = get_nodes_block(node);
+
+                               DB((dbg, LEVEL_2, "Node %+F in block %+F is unmovable\n", node, block));
+                               set_Block_mark(block, 1);
+                       }
+               }
+       }
 }
 
-typedef struct _cond_walk_info_t {
-  struct obstack *obst;
-  struct list_head cond_info_head;
-  struct list_head phi_head;
-} cond_walk_info_t;
-
-
-static void annotate_cond_info_pre(ir_node *irn, void *data)
+static void optimise_muxs_0(ir_node* mux, void* env)
 {
-  set_irn_link(irn, NULL);
+       ir_node* t;
+       ir_node* f;
+
+       (void) env;
+
+       if (!is_Mux(mux)) return;
+
+       t = get_Mux_true(mux);
+       f = get_Mux_false(mux);
+
+       DB((dbg, LEVEL_3, "Simplify %+F T=%+F F=%+F\n", mux, t, f));
+
+       if (is_Unknown(t)) {
+               DB((dbg, LEVEL_3, "Replace Mux with unknown operand by %+F\n", f));
+               exchange(mux, f);
+               return;
+       }
+       if (is_Unknown(f)) {
+               DB((dbg, LEVEL_3, "Replace Mux with unknown operand by %+F\n", t));
+               exchange(mux, t);
+               return;
+       }
+
+       if (is_Mux(t)) {
+               ir_graph* irg   = current_ir_graph;
+               ir_node*  block = get_nodes_block(mux);
+               ir_mode*  mode  = get_irn_mode(mux);
+               ir_node*  c0    = get_Mux_sel(mux);
+               ir_node*  c1    = get_Mux_sel(t);
+               ir_node*  t1    = get_Mux_true(t);
+               ir_node*  f1    = get_Mux_false(t);
+               if (f == f1) {
+                       /* Mux(c0, Mux(c1, x, y), y) -> typical if (c0 && c1) x else y */
+                       ir_node* and_    = new_r_And(irg, block, c0, c1, mode_b);
+                       ir_node* new_mux = new_r_Mux(irg, block, and_, f1, t1, mode);
+                       exchange(mux, new_mux);
+               } else if (f == t1) {
+                       /* Mux(c0, Mux(c1, x, y), x) */
+                       ir_node* not_c1 = new_r_Not(irg, block, c1, mode_b);
+                       ir_node* and_   = new_r_And(irg, block, c0, not_c1, mode_b);
+                       ir_node* new_mux = new_r_Mux(irg, block, and_, t1, f1, mode);
+                       exchange(mux, new_mux);
+               }
+       } else if (is_Mux(f)) {
+               ir_graph* irg   = current_ir_graph;
+               ir_node*  block = get_nodes_block(mux);
+               ir_mode*  mode  = get_irn_mode(mux);
+               ir_node*  c0    = get_Mux_sel(mux);
+               ir_node*  c1    = get_Mux_sel(f);
+               ir_node*  t1    = get_Mux_true(f);
+               ir_node*  f1    = get_Mux_false(f);
+               if (t == t1) {
+                       /* Mux(c0, x, Mux(c1, x, y)) -> typical if (c0 || c1) x else y */
+                       ir_node* or_     = new_r_Or(irg, block, c0, c1, mode_b);
+                       ir_node* new_mux = new_r_Mux(irg, block, or_, f1, t1, mode);
+                       exchange(mux, new_mux);
+               } else if (t == f1) {
+                       /* Mux(c0, x, Mux(c1, y, x)) */
+                       ir_node* not_c1  = new_r_Not(irg, block, c1, mode_b);
+                       ir_node* or_     = new_r_Or(irg, block, c0, not_c1, mode_b);
+                       ir_node* new_mux = new_r_Mux(irg, block, or_, t1, f1, mode);
+                       exchange(mux, new_mux);
+               }
+       }
 }
 
-static void annotate_cond_info_post(ir_node *irn, void *data)
-{
-  cond_walk_info_t *cwi = data;
-
-  /*
-   * Check, if the node is a phi
-   * we then compute a set of conds which are reachable from this
-   * phi's block up to its dominator.
-   * The set is attached to the blocks link field.
-   */
-  if(is_Phi(irn) && mode_is_datab(get_irn_mode(irn))) {
-    ir_node *block = get_nodes_block(irn);
-
-    cond_info_t *ci = get_irn_link(block);
-
-    /* If the set is not yet computed, do it now. */
-    if(!ci) {
-      ci = obstack_alloc(cwi->obst, sizeof(*ci));
-      ci->cond_set = new_set(cond_cmp, log2_ceil(get_irn_arity(block)));
-      ci->first_phi = irn;
-
-      INIT_LIST_HEAD(&ci->roots);
-      INIT_LIST_HEAD(&ci->list);
-
-      /*
-       * Add this cond info to the list of all cond infos
-       * in this graph. This is just done to free the
-       * set easier afterwards (we save an irg_walk_graph).
-       */
-      list_add(&cwi->cond_info_head, &ci->list);
-
-      DBG((dbg, LEVEL_2, "searching conds at %n\n", irn));
-
-      /*
-       * Fill the set with conds we find on the way from
-       * the block to its dominator.
-       */
-      find_conds(irn, ci);
-
-      /*
-       * If there where no suitable conds, delete the set
-       * immediately and reset the set pointer to NULL
-       */
-      if(set_count(ci->cond_set) == 0) {
-        del_set(ci->cond_set);
-        list_del(&ci->list);
-        obstack_free(cwi->obst, ci);
-        ci = NULL;
-      }
-    }
-
-    else
-      DBG((dbg, LEVEL_2, "conds already computed for %n (look at %n)\n", irn, ci->first_phi));
-
-    set_irn_link(block, ci);
-
-    if(ci) {
-      phi_info_t *pi = obstack_alloc(cwi->obst, sizeof(*pi));
-      pi->irn = irn;
-      pi->cond_info = ci;
-      INIT_LIST_HEAD(&pi->list);
-      list_add(&pi->list, &cwi->phi_head);
-    }
-
-  }
-}
 
-static void dump_conds(cond_t *cond, void *env)
+static void optimise_muxs_1(ir_node* mux, void* env)
 {
-  int i;
-  FILE *f = env;
-
-  ir_fprintf(f, "node:{title:\"n%p\" label:\"%n(%d, %d)\n%n\"}\n",
-      cond, cond->cond, cond->cases[0].pos, cond->cases[1].pos,
-      get_nodes_block(cond->cond));
-
-  for(i = 0; i < 2; ++i)
-    if(cond->cases[i].masked_by)
-      ir_fprintf(f, "edge:{sourcename:\"n%p\" targetname:\"n%p\" label:\"%d\"}\n",
-          cond, cond->cases[i].masked_by, i);
+       ir_node* t;
+       ir_node* f;
+       ir_mode* mode;
+
+       (void) env;
+
+       if (!is_Mux(mux)) return;
+
+       t = get_Mux_true(mux);
+       f = get_Mux_false(mux);
+
+       DB((dbg, LEVEL_3, "Simplify %+F T=%+F F=%+F\n", mux, t, f));
+
+       mode = get_irn_mode(mux);
+
+       if (is_Const(t) && is_Const(f) && (mode_is_int(mode))) {
+               ir_node* block = get_nodes_block(mux);
+               ir_node* c     = get_Mux_sel(mux);
+               tarval* tv_t = get_Const_tarval(t);
+               tarval* tv_f = get_Const_tarval(f);
+               if (tarval_is_one(tv_t) && tarval_is_null(tv_f)) {
+                       ir_node* conv  = new_r_Conv(current_ir_graph, block, c, mode);
+                       exchange(mux, conv);
+               } else if (tarval_is_null(tv_t) && tarval_is_one(tv_f)) {
+                       ir_node* not_  = new_r_Not(current_ir_graph, block, c, mode_b);
+                       ir_node* conv  = new_r_Conv(current_ir_graph, block, not_, mode);
+                       exchange(mux, conv);
+               }
+       }
 }
 
-static void vcg_dump_conds(ir_graph *irg, cond_walk_info_t *cwi)
-{
-  char buf[512];
-  FILE *f;
-
-  snprintf(buf, sizeof(buf), "%s-conds.vcg", get_entity_name(get_irg_entity(irg)));
-
-  if((f = fopen(buf, "wt")) != NULL) {
-    cond_info_t *ci;
-    phi_info_t *phi;
-    cond_t *cond;
-
-    ir_fprintf(f, "graph:{\ndisplay_edge_labels:yes\n");
-    list_for_each_entry(cond_info_t, ci, &cwi->cond_info_head, list) {
-      ir_fprintf(f, "node:{title:\"n%p\" label:\"cond info\"}\n", ci);
-      list_for_each_entry(cond_t, cond, &ci->roots, list) {
-        walk_conds(cond, NULL, dump_conds, f);
-        ir_fprintf(f, "edge:{sourcename:\"n%p\" targetname:\"n%p\"}\n", ci, cond);
-      }
-    }
-
-    list_for_each_entry(phi_info_t, phi, &cwi->phi_head, list) {
-      ir_fprintf(f, "node:{title:\"n%p\" label:\"%n\n%n\"}\n",
-          phi->irn, phi->irn, get_nodes_block(phi->irn));
-      ir_fprintf(f, "edge:{sourcename:\"n%p\" targetname:\"n%p\"}\n", phi->irn, phi->cond_info);
-    }
-    fprintf(f, "}\n");
-  }
-}
 
-void opt_if_conv(ir_graph *irg, const opt_if_conv_info_t *params)
+void opt_if_conv(ir_graph *irg, const ir_settings_if_conv_t *params)
 {
-  int muxes_made = 0;
-  struct obstack obst;
-  phi_info_t *phi_info;
-  cond_info_t *cond_info;
-  cond_walk_info_t cwi;
-
-  opt_if_conv_info_t p;
-
-  if(!get_opt_if_conversion())
-    return;
+       ir_settings_if_conv_t p;
 
-  /* get the parameters */
-  if (params)
-    memcpy(&p, params, sizeof(p));
-  else
-    memcpy(&p, &default_info, sizeof(p));
+       /* get the parameters */
+       p = (params != NULL ? *params : default_info);
 
-  if (! p.allow_mux)
-    p.allow_mux = default_info.allow_mux;
+       FIRM_DBG_REGISTER(dbg, "firm.opt.ifconv");
 
-  obstack_init(&obst);
+       DB((dbg, LEVEL_1, "Running if-conversion on %+F\n", irg));
 
-  cwi.obst = &obst;
-  INIT_LIST_HEAD(&cwi.cond_info_head);
-  INIT_LIST_HEAD(&cwi.phi_head);
+       normalize_one_return(irg);
+       remove_critical_cf_edges(irg);
 
-  /* Init the debug stuff. */
-  dbg = firm_dbg_register("firm.opt.ifconv");
-#if 0
-  firm_dbg_set_mask(dbg, LEVEL_1|LEVEL_2|LEVEL_3);
-#endif
+       compute_cdep(irg);
+       assure_doms(irg);
 
-  /* if-conversion works better with normalized returns */
-  normalize_one_return(irg);
+       ir_reserve_resources(irg, IR_RESOURCE_BLOCK_MARK);
 
-  /* Ensure, that the dominators are computed. */
-  compute_doms(irg);
+       irg_block_walk_graph(irg, init_block_link, NULL, NULL);
+       irg_walk_graph(irg, collect_phis, NULL, NULL);
+       irg_block_walk_graph(irg, NULL, if_conv_walker, &p);
 
-  DBG((dbg, LEVEL_1, "if conversion for irg %s(%p)\n",
-        get_entity_name(get_irg_entity(irg)), irg));
+       ir_free_resources(irg, IR_RESOURCE_BLOCK_MARK);
 
-  /*
-   * Collect information about the conds pu the phis on an obstack.
-   * It is important that phi nodes which are 'higher' (with a
-   * lower dfs pre order) are in front of the obstack. Since they are
-   * possibly turned in to muxes this can enable the optimization
-   * of 'lower' ones.
-   */
-  irg_walk_graph(irg, annotate_cond_info_pre, annotate_cond_info_post, &cwi);
+       local_optimize_graph(irg);
 
-#if 0
-  vcg_dump_conds(irg, &cwi);
+       irg_walk_graph(irg, NULL, optimise_muxs_0, NULL);
+#if 1
+       irg_walk_graph(irg, NULL, optimise_muxs_1, NULL);
 #endif
 
-  /* Process each suitable phi found. */
-  list_for_each_entry(phi_info_t, phi_info, &cwi.phi_head, list) {
-    DBG((dbg, LEVEL_2, "phi node %n\n", phi_info->irn));
-    muxes_made += check_out_phi(phi_info, &p);
-  }
-
-  list_for_each_entry(cond_info_t, cond_info, &cwi.cond_info_head, list) {
-    del_set(cond_info->cond_set);
-  }
-
-  DBG((dbg, LEVEL_1, "muxes made: %d\n", muxes_made));
+       /* TODO: graph might be changed, handle more graceful */
+       set_irg_outs_inconsistent(irg);
+       set_irg_extblk_inconsistent(irg);
+       set_irg_loopinfo_inconsistent(irg);
+       free_dom(irg);
 
-  obstack_free(&obst, NULL);
+       free_cdep(irg);
 }