cleanup: Remove pointless assert(is_${NODE}(x)) just before get_${NODE}_${FOO}(x...
[libfirm] / ir / ana / irdom.c
index 397b93e..2b98e13 100644 (file)
@@ -1,60 +1,62 @@
 /*
- * Project:     libFIRM
- * File name:   ir/ana/irdom.c
- * Purpose:     Construct and access dominator / post dominator tree.
- * Author:      Goetz Lindenmaier
- * Modified by: Michael Beck, Rubino Geiss
- * Created:     2.2002
- * CVS-ID:      $Id$
- * Copyright:   (c) 2002-2003 Universitaet 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.
  */
 
-#ifdef HAVE_CONFIG_H
+/**
+ * @file
+ * @brief     Construct and access dominator / post dominator tree.
+ * @author    Goetz Lindenmaier, Michael Beck, Rubino Geiss
+ * @date      2.2002
+ */
 #include "config.h"
-#endif
-
-#ifdef HAVE_MALLOC_H
-#include <malloc.h>
-#endif
-#ifdef HAVE_ALLOCA_H
-#include <alloca.h>
-#endif
-#ifdef HAVE_STRING_H
+
 #include <string.h>
-#endif
 
 #include "irouts.h"
 
 #include "xmalloc.h"
 #include "irgwalk.h"
 #include "irdom_t.h"
-#include "irgraph_t.h"   /* To access state field. */
+#include "irgraph_t.h"
 #include "irnode_t.h"
 #include "ircons_t.h"
-#include "array.h"
+#include "array_t.h"
+#include "iredges.h"
 
 
 #define get_dom_info(bl)  (&(bl)->attr.block.dom)
 #define get_pdom_info(bl) (&(bl)->attr.block.pdom)
 
-/*--------------------------------------------------------------------*/
-/** Accessing the dominator and post dominator data structures       **/
-/*--------------------------------------------------------------------*/
-
-ir_node *get_Block_idom(const ir_node *bl) {
-  assert(is_Block(bl));
-  if (get_Block_dom_depth(bl) == -1) {
-    /* This block is not reachable from Start */
-    return new_Bad();
-  }
-  return get_dom_info(bl)->idom;
+ir_node *get_Block_idom(const ir_node *bl)
+{
+       if (get_Block_dom_depth(bl) == -1) {
+               /* This block is not reachable from Start */
+               ir_graph *irg = get_irn_irg(bl);
+               return new_r_Bad(irg, mode_BB);
+       }
+       return get_dom_info(bl)->idom;
 }
 
-void set_Block_idom(ir_node *bl, ir_node *n) {
-       dom_info *bli = get_dom_info(bl);
+void set_Block_idom(ir_node *bl, ir_node *n)
+{
+       ir_dom_info *bli = get_dom_info(bl);
 
-  assert(get_irn_op(bl) == op_Block);
+       assert(is_Block(bl));
 
        /* Set the immediate dominator of bl to n */
        bli->idom = n;
@@ -63,27 +65,29 @@ void set_Block_idom(ir_node *bl, ir_node *n) {
         * If we don't set the root of the dominator tree
         * Append bl to the dominates queue of n.
         */
-       if(n != NULL) {
-               dom_info *ni = get_dom_info(n);
+       if (n != NULL) {
+               ir_dom_info *ni = get_dom_info(n);
 
                bli->next = ni->first;
                ni->first = bl;
        }
 }
 
-ir_node *get_Block_ipostdom(const ir_node *bl) {
-  assert(is_Block(bl));
-  if (get_Block_postdom_depth(bl) == -1) {
-    /* This block is not reachable from Start */
-    return new_Bad();
-  }
-  return get_pdom_info(bl)->idom;
+ir_node *get_Block_ipostdom(const ir_node *bl)
+{
+       if (get_Block_postdom_depth(bl) == -1) {
+               /* This block is not reachable from Start */
+               ir_graph *irg = get_irn_irg(bl);
+               return new_r_Bad(irg, mode_BB);
+       }
+       return get_pdom_info(bl)->idom;
 }
 
-void set_Block_ipostdom(ir_node *bl, ir_node *n) {
-       dom_info *bli = get_pdom_info(bl);
+void set_Block_ipostdom(ir_node *bl, ir_node *n)
+{
+       ir_dom_info *bli = get_pdom_info(bl);
 
-  assert(get_irn_op(bl) == op_Block);
+       assert(is_Block(bl));
 
        /* Set the immediate post dominator of bl to n */
        bli->idom = n;
@@ -92,53 +96,61 @@ void set_Block_ipostdom(ir_node *bl, ir_node *n) {
         * If we don't set the root of the post dominator tree
         * Append bl to the post dominates queue of n.
         */
-       if(n != NULL) {
-               dom_info *ni = get_pdom_info(n);
+       if (n != NULL) {
+               ir_dom_info *ni = get_pdom_info(n);
 
                bli->next = ni->first;
                ni->first = bl;
        }
 }
 
-int get_Block_dom_pre_num(const ir_node *bl) {
-  assert(get_irn_op(bl) == op_Block);
-  return get_dom_info(bl)->pre_num;
+int get_Block_dom_pre_num(const ir_node *bl)
+{
+       assert(is_Block(bl));
+       return get_dom_info(bl)->pre_num;
 }
 
-void set_Block_dom_pre_num(ir_node *bl, int num) {
-  assert(get_irn_op(bl) == op_Block);
-  get_dom_info(bl)->pre_num = num;
+void set_Block_dom_pre_num(ir_node *bl, int num)
+{
+       assert(is_Block(bl));
+       get_dom_info(bl)->pre_num = num;
 }
 
-int get_Block_dom_depth(const ir_node *bl) {
-  assert(get_irn_op(bl) == op_Block);
-  return get_dom_info(bl)->dom_depth;
+int get_Block_dom_depth(const ir_node *bl)
+{
+       assert(is_Block(bl));
+       return get_dom_info(bl)->dom_depth;
 }
 
-void set_Block_dom_depth(ir_node *bl, int depth) {
-  assert(get_irn_op(bl) == op_Block);
-  get_dom_info(bl)->dom_depth = depth;
+void set_Block_dom_depth(ir_node *bl, int depth)
+{
+       assert(is_Block(bl));
+       get_dom_info(bl)->dom_depth = depth;
 }
 
 
-int get_Block_postdom_pre_num(const ir_node *bl) {
-  assert(get_irn_op(bl) == op_Block);
-  return get_pdom_info(bl)->pre_num;
+int get_Block_postdom_pre_num(const ir_node *bl)
+{
+       assert(is_Block(bl));
+       return get_pdom_info(bl)->pre_num;
 }
 
-void set_Block_postdom_pre_num(ir_node *bl, int num) {
-  assert(get_irn_op(bl) == op_Block);
-  get_pdom_info(bl)->pre_num = num;
+void set_Block_postdom_pre_num(ir_node *bl, int num)
+{
+       assert(is_Block(bl));
+       get_pdom_info(bl)->pre_num = num;
 }
 
-int get_Block_postdom_depth(const ir_node *bl) {
-  assert(get_irn_op(bl) == op_Block);
-  return get_pdom_info(bl)->dom_depth;
+int get_Block_postdom_depth(const ir_node *bl)
+{
+       assert(is_Block(bl));
+       return get_pdom_info(bl)->dom_depth;
 }
 
-void set_Block_postdom_depth(ir_node *bl, int depth) {
-  assert(get_irn_op(bl) == op_Block);
-  get_pdom_info(bl)->dom_depth = depth;
+void set_Block_postdom_depth(ir_node *bl, int depth)
+{
+       assert(is_Block(bl));
+       get_pdom_info(bl)->dom_depth = depth;
 }
 
 unsigned get_Block_dom_tree_pre_num(const ir_node *bl)
@@ -165,10 +177,9 @@ unsigned get_Block_pdom_max_subtree_pre_num(const ir_node *bl)
        return get_pdom_info(bl)->max_subtree_pre_num;
 }
 
-/* Check, if a block dominates another block. */
 int block_dominates(const ir_node *a, const ir_node *b)
 {
-       const dom_info *ai, *bi;
+       const ir_dom_info *ai, *bi;
 
        if (is_Block(a) && is_Block(b)) {
                ai = get_dom_info(a);
@@ -180,6 +191,38 @@ int block_dominates(const ir_node *a, const ir_node *b)
        return 0;
 }
 
+int block_strictly_dominates(const ir_node *a, const ir_node *b)
+{
+       return (a != b) && block_dominates(a, b);
+}
+
+ir_node *node_smallest_common_dominator(ir_node *a, ir_node *b)
+{
+       ir_node *bl_a   = is_Block(a) ? a : get_nodes_block(a);
+       ir_node *bl_b   = is_Block(b) ? b : get_nodes_block(b);
+       ir_node *dom_bl = NULL;
+
+       /* Check if block of a dominates block of b */
+       if (block_dominates(bl_a, bl_b))
+               dom_bl = bl_a;
+       /* Check if block of b dominates block of a */
+       else if (block_dominates(bl_b, bl_a))
+               dom_bl = bl_b;
+       else {
+               /* walk up dominator tree and search for first block dominating a and b */
+               while (! dom_bl) {
+                       bl_a = get_Block_idom(bl_a);
+
+                       assert(! is_Bad(bl_a) && "block is dead?");
+
+                       if (block_dominates(bl_a, bl_b))
+                               dom_bl = bl_a;
+               }
+       }
+
+       return dom_bl;
+}
+
 /* Get the first node in the list of nodes dominated by a given block. */
 ir_node *get_Block_dominated_first(const ir_node *bl)
 {
@@ -187,18 +230,15 @@ ir_node *get_Block_dominated_first(const ir_node *bl)
        return get_dom_info(bl)->first;
 }
 
-/* Get the next node in a list of nodes which are dominated by some
- * other node. */
 ir_node *get_Block_dominated_next(const ir_node *bl)
 {
        assert(is_Block(bl));
        return get_dom_info(bl)->next;
 }
 
-/* Check, if a block post dominates another block. */
 int block_postdominates(const ir_node *a, const ir_node *b)
 {
-       const dom_info *ai, *bi;
+       const ir_dom_info *ai, *bi;
 
        if (is_Block(a) && is_Block(b)) {
                ai = get_pdom_info(a);
@@ -210,63 +250,62 @@ int block_postdominates(const ir_node *a, const ir_node *b)
        return 0;
 }
 
-/* Get the first node in the list of nodes post dominated by a given block. */
+int block_strictly_postdominates(const ir_node *a, const ir_node *b)
+{
+       return (a != b) && block_postdominates(a, b);
+}
+
 ir_node *get_Block_postdominated_first(const ir_node *bl)
 {
        assert(is_Block(bl));
        return get_pdom_info(bl)->first;
 }
 
-/* Get the next node in a list of nodes which are post dominated by some
- * other node. */
 ir_node *get_Block_postdominated_next(const ir_node *bl)
 {
        assert(is_Block(bl));
        return get_pdom_info(bl)->next;
 }
 
-/* Visit all nodes in the dominator subtree of a given node. */
 void dom_tree_walk(ir_node *bl, irg_walk_func *pre,
                irg_walk_func *post, void *env)
 {
        ir_node *p;
 
-       if(pre)
+       if (pre)
                pre(bl, env);
 
        dominates_for_each(bl, p) {
                dom_tree_walk(p, pre, post, env);
        }
 
-       if(post)
+       if (post)
                post(bl, env);
 }
 
-/* Visit all nodes in the post dominator subtree of a given node. */
 void postdom_tree_walk(ir_node *bl, irg_walk_func *pre,
                irg_walk_func *post, void *env)
 {
        ir_node *p;
 
-       if(pre)
+       if (pre)
                pre(bl, env);
 
        postdominates_for_each(bl, p) {
                postdom_tree_walk(p, pre, post, env);
        }
 
-       if(post)
+       if (post)
                post(bl, env);
 }
 
-/* Walk over the dominator tree of an irg starting at the root. */
 void dom_tree_walk_irg(ir_graph *irg, irg_walk_func *pre,
                irg_walk_func *post, void *env)
 {
        /* The root of the dominator tree should be the Start block. */
        ir_node *root = get_irg_start_block(irg);
 
-  assert(irg->dom_state == dom_consistent
+       assert(irg_has_properties(irg, IR_GRAPH_PROPERTY_CONSISTENT_DOMINANCE)
                        && "The dominators of the irg must be consistent");
        assert(root && "The start block of the graph is NULL?");
        assert(get_dom_info(root)->idom == NULL
@@ -274,14 +313,13 @@ void dom_tree_walk_irg(ir_graph *irg, irg_walk_func *pre,
        dom_tree_walk(root, pre, post, env);
 }
 
-/* Walk over the post dominator tree of an irg starting at the root. */
 void postdom_tree_walk_irg(ir_graph *irg, irg_walk_func *pre,
                irg_walk_func *post, void *env)
 {
-       /* The root of the dominator tree should be the End block. */
+       /* The root of the post dominator tree should be the End block. */
        ir_node *root = get_irg_end_block(irg);
 
-  assert(irg->pdom_state == dom_consistent
+       assert(irg_has_properties(irg, IR_GRAPH_PROPERTY_CONSISTENT_POSTDOMINANCE)
                        && "The dominators of the irg must be consistent");
        assert(root && "The end block of the graph is NULL?");
        assert(get_pdom_info(root)->idom == NULL
@@ -292,20 +330,21 @@ void postdom_tree_walk_irg(ir_graph *irg, irg_walk_func *pre,
 
 static void assign_tree_dom_pre_order(ir_node *bl, void *data)
 {
-       unsigned *num = data;
-       dom_info *bi = get_dom_info(bl);
+       unsigned *num = (unsigned*) data;
+       ir_dom_info *bi = get_dom_info(bl);
 
        bi->tree_pre_num = (*num)++;
 }
 
 static void assign_tree_dom_pre_order_max(ir_node *bl, void *data)
 {
-       dom_info *bi = get_dom_info(bl);
+       ir_dom_info *bi = get_dom_info(bl);
        ir_node *p;
        unsigned max = 0;
        unsigned children = 0;
+       (void) data;
 
-       for(p = bi->first; p; p = get_dom_info(p)->next) {
+       for (p = bi->first; p; p = get_dom_info(p)->next) {
                unsigned max_p = get_dom_info(p)->max_subtree_pre_num;
                max = max > max_p ? max : max_p;
                children++;
@@ -317,20 +356,21 @@ static void assign_tree_dom_pre_order_max(ir_node *bl, void *data)
 
 static void assign_tree_postdom_pre_order(ir_node *bl, void *data)
 {
-       unsigned *num = data;
-       dom_info *bi = get_pdom_info(bl);
+       unsigned *num = (unsigned*) data;
+       ir_dom_info *bi = get_pdom_info(bl);
 
        bi->tree_pre_num = (*num)++;
 }
 
 static void assign_tree_postdom_pre_order_max(ir_node *bl, void *data)
 {
-       dom_info *bi = get_pdom_info(bl);
+       ir_dom_info *bi = get_pdom_info(bl);
        ir_node *p;
        unsigned max = 0;
        unsigned children = 0;
+       (void) data;
 
-       for(p = bi->first; p; p = get_pdom_info(p)->next) {
+       for (p = bi->first; p; p = get_pdom_info(p)->next) {
                unsigned max_p = get_pdom_info(p)->max_subtree_pre_num;
                max = max > max_p ? max : max_p;
                children++;
@@ -340,45 +380,43 @@ static void assign_tree_postdom_pre_order_max(ir_node *bl, void *data)
        assert(bi->max_subtree_pre_num >= bi->tree_pre_num);
 }
 
-/*--------------------------------------------------------------------*/
-/*  Building and Removing the dominator data structure                */
-/*--------------------------------------------------------------------*/
-
 /**
  * count the number of blocks and clears the post dominance info
  */
-static void count_and_init_blocks_pdom(ir_node *bl, void *env) {
-  int *n_blocks = (int *) env;
-  (*n_blocks) ++;
+static void count_and_init_blocks_pdom(ir_node *bl, void *env)
+{
+       int *n_blocks = (int *) env;
 
-       memset(get_pdom_info(bl), 0, sizeof(dom_info));
-  set_Block_ipostdom(bl, NULL);
-  set_Block_postdom_pre_num(bl, -1);
-  set_Block_postdom_depth(bl, -1);
+       (*n_blocks) ++;
+
+       memset(get_pdom_info(bl), 0, sizeof(ir_dom_info));
+       set_Block_ipostdom(bl, NULL);
+       set_Block_postdom_pre_num(bl, -1);
+       set_Block_postdom_depth(bl, -1);
 }
 
 /** temporary type used while constructing the dominator / post dominator tree. */
 typedef struct tmp_dom_info {
-  ir_node *block;               /**< backlink */
-
-  struct tmp_dom_info *semi;    /**< semidominator */
-  struct tmp_dom_info *parent;
-  struct tmp_dom_info *label;   /**< used for LINK and EVAL */
-  struct tmp_dom_info *ancestor;/**< used for LINK and EVAL */
-  struct tmp_dom_info *dom;     /**< After step 3, if the semidominator of w is
-                                     its immediate dominator, then w->dom is the
-                                     immediate dominator of w.  Otherwise w->dom
-                                     is a vertex v whose number is smaller than
-                                     w and whose immediate dominator is also w's
-                                     immediate dominator. After step 4, w->dom
-                                     is the immediate dominator of w.  */
-  struct tmp_dom_info *bucket;  /**< set of vertices with same semidominator */
+       ir_node *block;               /**< backlink */
+
+       struct tmp_dom_info *semi;    /**< semidominator */
+       struct tmp_dom_info *parent;
+       struct tmp_dom_info *label;   /**< used for LINK and EVAL */
+       struct tmp_dom_info *ancestor;/**< used for LINK and EVAL */
+       struct tmp_dom_info *dom;     /**< After step 3, if the semidominator of w is
+                                          its immediate dominator, then w->dom is the
+                                          immediate dominator of w.  Otherwise w->dom
+                                          is a vertex v whose number is smaller than
+                                          w and whose immediate dominator is also w's
+                                          immediate dominator. After step 4, w->dom
+                                          is the immediate dominator of w.  */
+       struct tmp_dom_info *bucket;  /**< set of vertices with same semidominator */
 } tmp_dom_info;
 
 /** Struct to pass info through walker. */
 typedef struct {
-  tmp_dom_info *d;
-  int used;
+       tmp_dom_info *d;
+       int used;
 } dom_env;
 
 
@@ -387,32 +425,37 @@ typedef struct {
  * Start block misses control dead blocks.
  */
 static void init_tmp_dom_info(ir_node *bl, tmp_dom_info *parent,
-                             tmp_dom_info *tdi_list, int* used) {
-  tmp_dom_info *tdi;
-  int i;
-
-  assert(is_Block(bl));
-  if (get_irg_block_visited(current_ir_graph) == get_Block_block_visited(bl))
-    return;
-  mark_Block_block_visited(bl);
-  set_Block_dom_pre_num(bl, *used);
-
-  tdi = &tdi_list[*used];
-  ++(*used);
-
-  tdi->semi = tdi;
-  tdi->label = tdi;
-  tdi->ancestor = NULL;
-  tdi->bucket = NULL;
-  tdi->parent = parent;
-  tdi->block = bl;
-
-  /* Iterate */
-  for (i = get_Block_n_cfg_outs_ka(bl) - 1; i >= 0; --i) {
-    ir_node *pred = get_Block_cfg_out_ka(bl, i);
-    assert(is_Block(pred));
-    init_tmp_dom_info(pred, tdi, tdi_list, used);
-  }
+                              tmp_dom_info *tdi_list, int *used, int n_blocks)
+{
+       tmp_dom_info *tdi;
+       int i;
+
+       if (Block_block_visited(bl))
+         return;
+       mark_Block_block_visited(bl);
+       set_Block_dom_pre_num(bl, *used);
+
+       assert(*used < n_blocks);
+       tdi = &tdi_list[*used];
+       ++(*used);
+
+       tdi->semi     = tdi;
+       tdi->label    = tdi;
+       tdi->ancestor = NULL;
+       tdi->bucket   = NULL;
+       tdi->parent   = parent;
+       tdi->block    = bl;
+
+       /* Iterate */
+       for (i = get_Block_n_cfg_outs_ka(bl) - 1; i >= 0; --i) {
+               ir_node *pred = get_Block_cfg_out_ka(bl, i);
+               /* can happen for half-optimized dead code (I've seen this in student
+                  projects */
+               if (!is_Block(pred))
+                       continue;
+
+               init_tmp_dom_info(pred, tdi, tdi_list, used, n_blocks);
+       }
 }
 
 /**
@@ -420,365 +463,346 @@ static void init_tmp_dom_info(ir_node *bl, tmp_dom_info *parent,
  * End block misses blocks in endless loops.
  */
 static void init_tmp_pdom_info(ir_node *bl, tmp_dom_info *parent,
-                             tmp_dom_info *tdi_list, int* used) {
-  tmp_dom_info *tdi;
-  int i;
-
-  assert(is_Block(bl));
-  if (get_irg_block_visited(current_ir_graph) == get_Block_block_visited(bl))
-    return;
-  mark_Block_block_visited(bl);
-  set_Block_postdom_pre_num(bl, *used);
-
-  tdi = &tdi_list[*used];
-  ++(*used);
-
-  tdi->semi = tdi;
-  tdi->label = tdi;
-  tdi->ancestor = NULL;
-  tdi->bucket = NULL;
-  tdi->parent = parent;
-  tdi->block = bl;
-
-  /* Iterate */
-  for (i = get_Block_n_cfgpreds(bl) - 1; i >= 0; --i) {
-    ir_node *pred = get_Block_cfgpred_block(bl, i);
-    if (is_Bad(pred))
-      continue;
-    assert(is_Block(pred));
-    init_tmp_pdom_info(pred, tdi, tdi_list, used);
-  }
+                               tmp_dom_info *tdi_list, int* used, int n_blocks)
+{
+       tmp_dom_info *tdi;
+       int i;
+
+       if (get_irg_block_visited(current_ir_graph) == get_Block_block_visited(bl))
+         return;
+       mark_Block_block_visited(bl);
+       set_Block_postdom_pre_num(bl, *used);
+
+       assert(*used < n_blocks);
+       tdi = &tdi_list[*used];
+       ++(*used);
+
+       tdi->semi = tdi;
+       tdi->label = tdi;
+       tdi->ancestor = NULL;
+       tdi->bucket = NULL;
+       tdi->parent = parent;
+       tdi->block = bl;
+
+       /* Iterate */
+       for (i = get_Block_n_cfgpreds(bl) - 1; i >= 0; --i) {
+               ir_node *pred = get_Block_cfgpred_block(bl, i);
+               if (is_Bad(pred))
+                       continue;
+               init_tmp_pdom_info(pred, tdi, tdi_list, used, n_blocks);
+       }
+
+       /* Handle keep-alives. Note that the preprocessing
+          in init_construction() had already killed all
+          phantom keep-alive edges. All remaining block keep-alives
+          are really edges to endless loops.
+        */
+       if (bl == get_irg_end_block(current_ir_graph)) {
+               ir_node *end = get_irg_end(current_ir_graph);
+
+               for (i = get_irn_arity(end) - 1; i >= 0; --i) {
+                       ir_node *pred = get_irn_n(end, i);
+
+                       if (is_Block(pred))
+                               init_tmp_pdom_info(pred, tdi, tdi_list, used, n_blocks);
+               }
+       }
 }
 
 static void dom_compress(tmp_dom_info *v)
 {
-  assert (v->ancestor);
-  if (v->ancestor->ancestor) {
-    dom_compress (v->ancestor);
-    if (v->ancestor->label->semi < v->label->semi) {
-      v->label = v->ancestor->label;
-    }
-    v->ancestor = v->ancestor->ancestor;
-  }
+       assert (v->ancestor);
+       if (v->ancestor->ancestor) {
+               dom_compress (v->ancestor);
+               if (v->ancestor->label->semi < v->label->semi) {
+                       v->label = v->ancestor->label;
+               }
+               v->ancestor = v->ancestor->ancestor;
+       }
 }
 
 /**
  * if V is a root, return v, else return the vertex u, not being the
  * root, with minimum u->semi on the path from v to its root.
  */
-INLINE static tmp_dom_info *dom_eval (tmp_dom_info *v)
+inline static tmp_dom_info *dom_eval(tmp_dom_info *v)
 {
-  if (!v->ancestor) return v;
-  dom_compress (v);
-  return v->label;
+       if (!v->ancestor) return v;
+       dom_compress (v);
+       return v->label;
 }
 
 /** make V W's ancestor */
-INLINE static void dom_link(tmp_dom_info *v, tmp_dom_info *w)
+inline static void dom_link(tmp_dom_info *v, tmp_dom_info *w)
 {
-  w->ancestor = v;
+       w->ancestor = v;
 }
 
 /**
  * Walker: count the number of blocks and clears the dominance info
  */
-static void count_and_init_blocks_dom(ir_node *bl, void *env) {
-  int *n_blocks = (int *) env;
-  (*n_blocks) ++;
+static void count_and_init_blocks_dom(ir_node *bl, void *env)
+{
+       int *n_blocks = (int *) env;
 
-  memset(get_dom_info(bl), 0, sizeof(dom_info));
-  set_Block_idom(bl, NULL);
-  set_Block_dom_pre_num(bl, -1);
-  set_Block_dom_depth(bl, -1);
+       (*n_blocks) ++;
+
+       memset(get_dom_info(bl), 0, sizeof(ir_dom_info));
+       set_Block_idom(bl, NULL);
+       set_Block_dom_pre_num(bl, -1);
+       set_Block_dom_depth(bl, -1);
 }
 
-/**
- * Initialize the dominance/postdominance construction:
- *
- * - count the number of blocks
- * - clear the dominance info
- * - remove block-keepalives of live blocks to reduce
- *   the number of "phantom" block edges
- *
- * @param irg  the graph
- * @param pre  a walker function that will be called for every block in the graph
- */
-static int init_construction(ir_graph *irg, irg_walk_func *pre) {
-  ir_graph *rem = current_ir_graph;
-  ir_node *end;
-  int arity;
-  int n_blocks = 0;
-
-  current_ir_graph = irg;
-
-  /* this visits only the reachable blocks */
-  irg_block_walk(get_irg_end_block(irg), pre, NULL, &n_blocks);
-
-  /* now visit the unreachable (from End) Blocks and remove unnecessary keep-alives */
-  end   = get_irg_end(irg);
-  arity = get_irn_arity(end);
-  if (arity) {    /* we have keep-alives */
-    ir_node **in;
-    int i, j;
-
-    NEW_ARR_A(ir_node *, in, arity);
-    for (i = j = 0; i < arity; i++) {
-      ir_node *pred = get_irn_n(end, i);
-
-      if (get_irn_op(pred) == op_Block) {
-        if (Block_not_block_visited(pred)) {
-          /* we found a endless loop */
-          dec_irg_block_visited(irg);
-          irg_block_walk(pred, pre, NULL, &n_blocks);
-        }
-        else
-          continue;
-      }
-      in[j++] = pred;
-    }
-    if (j != arity) {
-      /* we kill some Block keep-alives */
-      set_irn_in(end, j, in);
-      set_irg_outs_inconsistent(irg);
-    }
-  }
-
-  current_ir_graph = rem;
-  return n_blocks;
-}
-
-
-/* Computes the dominator trees.  Sets a flag in irg to "dom_consistent".
-   If the control flow of the graph is changed this flag must be set to
-   "dom_inconsistent".  */
-void compute_doms(ir_graph *irg) {
-  ir_graph *rem = current_ir_graph;
-  int n_blocks, used, i, j;
-  tmp_dom_info *tdi_list;   /* Ein Golf? */
-
-  current_ir_graph = irg;
-
-  /* Update graph state */
-  assert(get_irg_phase_state(irg) != phase_building);
-  irg->dom_state = dom_consistent;
-
-  /* Count the number of blocks in the graph. */
-  n_blocks = init_construction(irg, count_and_init_blocks_dom);
-
-  /* Memory for temporary information. */
-  tdi_list = xcalloc(n_blocks, sizeof(tdi_list[0]));
-
-  /* We need the out data structure. */
-  if (irg->outs_state != outs_consistent)
-    compute_irg_outs(irg);
-
-  /* this with a standard walker as passing the parent to the sons isn't
-     simple. */
-  used = 0;
-  inc_irg_block_visited(irg);
-  init_tmp_dom_info(get_irg_start_block(irg), NULL, tdi_list, &used);
-  /* If not all blocks are reachable from Start by out edges this assertion
-     fails.
-     assert(used == n_blocks && "Precondition for dom construction violated"); */
-  n_blocks = used;
-
-
-  for (i = n_blocks-1; i > 0; i--) {  /* Don't iterate the root, it's done. */
-    int irn_arity;
-    tmp_dom_info *w = &tdi_list[i];
-    tmp_dom_info *v;
-
-    /* Step 2 */
-    irn_arity = get_irn_arity(w->block);
-    for (j = 0; j < irn_arity;  j++) {
-      ir_node *pred = get_Block_cfgpred_block(w->block, j);
-      tmp_dom_info *u;
-
-      if (is_Bad(pred) || (get_Block_dom_pre_num (pred) == -1))
-        continue;      /* control-dead */
-
-      u = dom_eval (&tdi_list[get_Block_dom_pre_num(pred)]);
-      if (u->semi < w->semi) w->semi = u->semi;
-    }
-
-    /* handle keep-alives if we are at the end block */
-    if (w->block == get_irg_end_block(irg)) {
-      ir_node *end = get_irg_end(irg);
-
-      irn_arity = get_irn_arity(end);
-      for (j = 0; j < irn_arity;  j++) {
-        ir_node *pred = get_irn_n(end, j);
-        tmp_dom_info *u;
-
-        if (is_no_Block(pred))
-          continue;
-
-        if (get_Block_dom_pre_num(pred) == -1)
-          continue;    /* control-dead */
-
-        u = dom_eval (&tdi_list[get_Block_dom_pre_num(pred)]);
-        if (u->semi < w->semi) w->semi = u->semi;
-      }
-    }
-
-    /* Add w to w->semi's bucket.  w is in exactly one bucket, so
-       buckets can been implemented as linked lists. */
-    w->bucket = w->semi->bucket;
-    w->semi->bucket = w;
-
-    dom_link (w->parent, w);
-
-    /* Step 3 */
-    while (w->parent->bucket) {
-      tmp_dom_info *u;
-      v = w->parent->bucket;
-      /* remove v from w->parent->bucket */
-      w->parent->bucket = v->bucket;
-      v->bucket = NULL;
-
-      u = dom_eval (v);
-      if (u->semi < v->semi)
-        v->dom = u;
-      else
-        v->dom = w->parent;
-    }
-  }
-  /* Step 4 */
-  tdi_list[0].dom = NULL;
-  set_Block_idom(tdi_list[0].block, NULL);
-  set_Block_dom_depth(tdi_list[0].block, 1);
-  for (i = 1; i < n_blocks;  i++) {
-    tmp_dom_info *w = &tdi_list[i];
-
-    if (w->dom != w->semi) w->dom = w->dom->dom;
-    set_Block_idom(w->block, w->dom->block);
-    set_Block_dom_depth(w->block, get_Block_dom_depth(w->dom->block) + 1);
-  }
-
-  /* clean up */
-  free(tdi_list);
-  current_ir_graph = rem;
-
-  /* Do a walk over the tree and assign the tree pre orders. */
-  {
-    unsigned tree_pre_order = 0;
-    dom_tree_walk_irg(irg, assign_tree_dom_pre_order,
-      assign_tree_dom_pre_order_max, &tree_pre_order);
-  }
-}
-
-void free_dom(ir_graph *irg) {
-  /* Update graph state */
-  assert(get_irg_phase_state(current_ir_graph) != phase_building);
-  current_ir_graph->dom_state = dom_none;
-
-  /* With the implementation right now there is nothing to free,
-     but better call it anyways... */
-}
-
-/* Computes the post dominator trees.  Sets a flag in irg to "dom_consistent".
-   If the control flow of the graph is changed this flag must be set to
-   "dom_inconsistent".  */
-void compute_postdoms(ir_graph *irg) {
-  ir_graph *rem = current_ir_graph;
-  int n_blocks, used, i, j;
-  tmp_dom_info *tdi_list;
-
-  current_ir_graph = irg;
-
-  /* Update graph state */
-  assert(get_irg_phase_state(irg) != phase_building);
-  irg->pdom_state = dom_consistent;
-
-  /* Count the number of blocks in the graph. */
-  n_blocks = init_construction(irg, count_and_init_blocks_pdom);
-
-  /* Memory for temporary information. */
-  tdi_list = xcalloc(n_blocks, sizeof(tdi_list[0]));
-
-  /* We need the out data structure. */
-  if (irg->outs_state != outs_consistent)
-    compute_irg_outs(irg);
-
-  /* this with a standard walker as passing the parent to the sons isn't
-     simple. */
-  used = 0;
-  inc_irg_block_visited(irg);
-  init_tmp_pdom_info(get_irg_end_block(irg), NULL, tdi_list, &used);
-  /* If not all blocks are reachable from End by cfg edges this assertion
-     fails.
-     assert(used == n_blocks && "Precondition for dom construction violated"); */
-  n_blocks = used;
-
-
-  for (i = n_blocks-1; i > 0; i--) {  /* Don't iterate the root, it's done. */
-    int irn_arity;
-    tmp_dom_info *w = &tdi_list[i];
-    tmp_dom_info *v;
-
-    /* Step 2 */
-    irn_arity = get_Block_n_cfg_outs(w->block);
-    for (j = 0;  j < irn_arity;  j++) {
-      ir_node *succ = get_Block_cfg_out(w->block, j);
-      tmp_dom_info *u;
-
-      if (get_Block_postdom_pre_num (succ) == -1)
-        continue;      /* endless-loop */
-
-      u = dom_eval (&tdi_list[get_Block_postdom_pre_num(succ)]);
-      if (u->semi < w->semi) w->semi = u->semi;
-    }
-    /* Add w to w->semi's bucket.  w is in exactly one bucket, so
-       buckets can be implemented as linked lists. */
-    w->bucket = w->semi->bucket;
-    w->semi->bucket = w;
-
-    dom_link (w->parent, w);
-
-    /* Step 3 */
-    while (w->parent->bucket) {
-      tmp_dom_info *u;
-      v = w->parent->bucket;
-      /* remove v from w->parent->bucket */
-      w->parent->bucket = v->bucket;
-      v->bucket = NULL;
-
-      u = dom_eval(v);
-      if (u->semi < v->semi)
-        v->dom = u;
-      else
-        v->dom = w->parent;
-    }
-  }
-  /* Step 4 */
-  tdi_list[0].dom = NULL;
-  set_Block_ipostdom(tdi_list[0].block, NULL);
-  set_Block_postdom_depth(tdi_list[0].block, 1);
-  for (i = 1;  i < n_blocks;  i++) {
-    tmp_dom_info *w = &tdi_list[i];
-
-    if (w->dom != w->semi) w->dom = w->dom->dom;
-    set_Block_ipostdom(w->block, w->dom->block);
-    set_Block_postdom_depth(w->block, get_Block_postdom_depth(w->dom->block) + 1);
-  }
-
-  /* clean up */
-  free(tdi_list);
-  irg = rem;
-
-  /* Do a walk over the tree and assign the tree pre orders. */
-  {
-    unsigned tree_pre_order = 0;
-    postdom_tree_walk_irg(irg, assign_tree_postdom_pre_order,
-      assign_tree_postdom_pre_order_max, &tree_pre_order);
-  }
-}
-
-void free_postdom(ir_graph *irg) {
-  /* Update graph state */
-  assert(get_irg_phase_state(current_ir_graph) != phase_building);
-  current_ir_graph->pdom_state = dom_none;
-
-  /* With the implementation right now there is nothing to free,
-     but better call it anyways... */
+void compute_doms(ir_graph *irg)
+{
+       ir_graph *rem = current_ir_graph;
+       int n_blocks, used, i, j;
+       tmp_dom_info *tdi_list;   /* Ein Golf? */
+
+       current_ir_graph = irg;
+
+       /* Update graph state */
+       assert(!irg_is_constrained(irg, IR_GRAPH_CONSTRAINT_CONSTRUCTION));
+
+       /* Count the number of blocks in the graph. */
+       n_blocks = 0;
+       irg_block_walk_graph(irg, count_and_init_blocks_dom, NULL, &n_blocks);
+
+       /* Memory for temporary information. */
+       tdi_list = XMALLOCNZ(tmp_dom_info, n_blocks);
+
+       /* We need the out data structure. */
+       assure_irg_outs(irg);
+
+       /* this with a standard walker as passing the parent to the sons isn't
+          simple. */
+       used = 0;
+       inc_irg_block_visited(irg);
+       init_tmp_dom_info(get_irg_start_block(irg), NULL, tdi_list, &used, n_blocks);
+       /* If not all blocks are reachable from Start by out edges this assertion
+          fails.
+          assert(used == n_blocks && "Precondition for dom construction violated"); */
+       assert(used <= n_blocks && "Precondition for dom construction violated");
+       n_blocks = used;
+
+
+       for (i = n_blocks-1; i > 0; i--) {  /* Don't iterate the root, it's done. */
+               tmp_dom_info *w     = &tdi_list[i];
+               ir_node      *block = w->block;
+               tmp_dom_info *v;
+               int           irn_arity;
+
+               /* Step 2 */
+               irn_arity = get_irn_arity(block);
+               for (j = 0; j < irn_arity;  j++) {
+                       ir_node *pred       = get_Block_cfgpred(block, j);
+                       ir_node *pred_block = get_nodes_block(pred);
+                       tmp_dom_info *u;
+
+                       if (is_Bad(pred) || (get_Block_dom_pre_num (pred_block) == -1))
+                               continue;    /* unreachable */
+
+                       u = dom_eval (&tdi_list[get_Block_dom_pre_num(pred_block)]);
+                       if (u->semi < w->semi)
+                               w->semi = u->semi;
+               }
+
+               /* handle keep-alives if we are at the end block */
+               if (block == get_irg_end_block(irg)) {
+                       ir_node *end = get_irg_end(irg);
+
+                       irn_arity = get_irn_arity(end);
+                       for (j = 0; j < irn_arity;  j++) {
+                               ir_node *pred = get_irn_n(end, j);
+                               tmp_dom_info *u;
+
+                               if (!is_Block(pred) || get_Block_dom_pre_num(pred) == -1)
+                                       continue;   /* unreachable */
+
+                               u = dom_eval (&tdi_list[get_Block_dom_pre_num(pred)]);
+                               if (u->semi < w->semi)
+                                       w->semi = u->semi;
+                       }
+               }
+
+               /* Add w to w->semi's bucket.  w is in exactly one bucket, so
+                  buckets can been implemented as linked lists. */
+               w->bucket = w->semi->bucket;
+               w->semi->bucket = w;
+
+               dom_link (w->parent, w);
+
+               /* Step 3 */
+               while (w->parent->bucket) {
+                       tmp_dom_info *u;
+                       v = w->parent->bucket;
+                       /* remove v from w->parent->bucket */
+                       w->parent->bucket = v->bucket;
+                       v->bucket = NULL;
+
+                       u = dom_eval (v);
+                       if (u->semi < v->semi)
+                               v->dom = u;
+                       else
+                               v->dom = w->parent;
+               }
+       }
+       /* Step 4 */
+       tdi_list[0].dom = NULL;
+       set_Block_idom(tdi_list[0].block, NULL);
+       set_Block_dom_depth(tdi_list[0].block, 1);
+       for (i = 1; i < n_blocks;  i++) {
+               tmp_dom_info *w = &tdi_list[i];
+               int depth;
+
+               if (! w->dom)
+                       continue; /* control dead */
+
+               if (w->dom != w->semi)
+                       w->dom = w->dom->dom;
+               set_Block_idom(w->block, w->dom->block);
+
+               /* blocks dominated by dead one's are still dead */
+               depth = get_Block_dom_depth(w->dom->block);
+               if (depth > 0)
+                       ++depth;
+               set_Block_dom_depth(w->block, depth);
+       }
+
+       /* clean up */
+       free(tdi_list);
+
+       /* Do a walk over the tree and assign the tree pre orders. */
+       {
+               unsigned tree_pre_order = 0;
+               dom_tree_walk(get_irg_start_block(irg), assign_tree_dom_pre_order,
+                                 assign_tree_dom_pre_order_max, &tree_pre_order);
+       }
+       current_ir_graph = rem;
+       add_irg_properties(irg, IR_GRAPH_PROPERTY_CONSISTENT_DOMINANCE);
+}
+
+void assure_doms(ir_graph *irg)
+{
+       if (! irg_has_properties(irg, IR_GRAPH_PROPERTY_CONSISTENT_DOMINANCE))
+               compute_doms(irg);
+}
+
+void free_dom(ir_graph *irg)
+{
+       /* Update graph state */
+       clear_irg_properties(irg, IR_GRAPH_PROPERTY_CONSISTENT_DOMINANCE);
+
+       /* With the implementation right now there is nothing to free */
+
+       /* free dominance frontiers */
+       ir_free_dominance_frontiers(irg);
+}
+
+void compute_postdoms(ir_graph *irg)
+{
+       ir_graph *rem = current_ir_graph;
+       int n_blocks, used, i, j;
+       tmp_dom_info *tdi_list;
+
+       current_ir_graph = irg;
+
+       /* Update graph state */
+       assert(!irg_is_constrained(irg, IR_GRAPH_CONSTRAINT_CONSTRUCTION));
+
+       /* Count the number of blocks in the graph. */
+       n_blocks = 0;
+       irg_block_walk_graph(irg, count_and_init_blocks_pdom, NULL, &n_blocks);
+
+       /* Memory for temporary information. */
+       tdi_list = XMALLOCNZ(tmp_dom_info, n_blocks);
+
+       /* We need the out data structure. */
+       assure_irg_outs(irg);
+
+       /* this with a standard walker as passing the parent to the sons isn't
+          simple. */
+       used = 0;
+       inc_irg_block_visited(irg);
+       init_tmp_pdom_info(get_irg_end_block(irg), NULL, tdi_list, &used, n_blocks);
+       /* If not all blocks are reachable from End by cfg edges this assertion
+          fails.
+          assert(used == n_blocks && "Precondition for dom construction violated"); */
+       n_blocks = used;
+
+
+       for (i = n_blocks-1; i > 0; i--) {  /* Don't iterate the root, it's done. */
+               int irn_arity;
+               tmp_dom_info *w = &tdi_list[i];
+               tmp_dom_info *v;
+
+               /* Step 2 */
+               irn_arity = get_Block_n_cfg_outs_ka(w->block);
+               for (j = 0;  j < irn_arity;  j++) {
+                       ir_node *succ = get_Block_cfg_out_ka(w->block, j);
+                       tmp_dom_info *u;
+
+                       if (get_Block_postdom_pre_num (succ) == -1)
+                               continue;    /* endless-loop */
+
+                       u = dom_eval (&tdi_list[get_Block_postdom_pre_num(succ)]);
+                       if (u->semi < w->semi) w->semi = u->semi;
+               }
+               /* Add w to w->semi's bucket.  w is in exactly one bucket, so
+                  buckets can be implemented as linked lists. */
+               w->bucket = w->semi->bucket;
+               w->semi->bucket = w;
+
+               dom_link (w->parent, w);
+
+               /* Step 3 */
+               while (w->parent->bucket) {
+                       tmp_dom_info *u;
+                       v = w->parent->bucket;
+                       /* remove v from w->parent->bucket */
+                       w->parent->bucket = v->bucket;
+                       v->bucket = NULL;
+
+                       u = dom_eval(v);
+                       if (u->semi < v->semi)
+                               v->dom = u;
+                       else
+                               v->dom = w->parent;
+               }
+       }
+       /* Step 4 */
+       tdi_list[0].dom = NULL;
+       set_Block_ipostdom(tdi_list[0].block, NULL);
+       set_Block_postdom_depth(tdi_list[0].block, 1);
+       for (i = 1;  i < n_blocks;  i++) {
+               tmp_dom_info *w = &tdi_list[i];
+
+               if (w->dom != w->semi) w->dom = w->dom->dom;
+               set_Block_ipostdom(w->block, w->dom->block);
+               set_Block_postdom_depth(w->block, get_Block_postdom_depth(w->dom->block) + 1);
+       }
+
+       /* clean up */
+       free(tdi_list);
+
+       /* Do a walk over the tree and assign the tree pre orders. */
+       {
+               unsigned tree_pre_order = 0;
+               postdom_tree_walk(get_irg_end_block(irg), assign_tree_postdom_pre_order,
+                       assign_tree_postdom_pre_order_max, &tree_pre_order);
+       }
+       current_ir_graph = rem;
+       add_irg_properties(irg, IR_GRAPH_PROPERTY_CONSISTENT_POSTDOMINANCE);
+}
+
+void assure_postdoms(ir_graph *irg)
+{
+       if (! irg_has_properties(irg, IR_GRAPH_PROPERTY_CONSISTENT_POSTDOMINANCE))
+               compute_postdoms(irg);
+}
+
+void free_postdom(ir_graph *irg)
+{
+       /* Update graph state */
+       clear_irg_properties(irg, IR_GRAPH_PROPERTY_CONSISTENT_POSTDOMINANCE);
 }