/*
* Project: libFIRM
* File name: ir/ana/irdom.c
- * Purpose: Construct and access dominator tree.
+ * Purpose: Construct and access dominator / post dominator tree.
* Author: Goetz Lindenmaier
- * Modified by:
+ * Modified by: Michael Beck, Rubino Geiss
* Created: 2.2002
* CVS-ID: $Id$
- * Copyright: (c) 2002-2003 Universitรคt Karlsruhe
+ * Copyright: (c) 2002-2003 Universitaet Karlsruhe
* Licence: This file protected by GPL - GNU GENERAL PUBLIC LICENSE.
*/
#include "ircons_t.h"
-#define get_dom_info(bl) (&(bl)->attr.block.dom)
+#define get_dom_info(bl) (&(bl)->attr.block.dom)
+#define get_pdom_info(bl) (&(bl)->attr.block.pdom)
/*--------------------------------------------------------------------*/
-/** Accessing the dominator data structures **/
+/** Accessing the dominator and post dominator data structures **/
/*--------------------------------------------------------------------*/
ir_node *get_Block_idom(const ir_node *bl) {
}
}
-int get_Block_pre_num(const ir_node *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;
+}
+
+void set_Block_ipostdom(ir_node *bl, ir_node *n) {
+ dom_info *bli = get_pdom_info(bl);
+
assert(get_irn_op(bl) == op_Block);
- return bl->attr.block.dom.pre_num;
+
+ /* Set the immediate post dominator of bl to n */
+ bli->idom = 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);
+
+ bli->next = ni->first;
+ ni->first = bl;
+ }
}
-void set_Block_pre_num(ir_node *bl, int num) {
+int get_Block_dom_pre_num(const ir_node *bl) {
assert(get_irn_op(bl) == op_Block);
- bl->attr.block.dom.pre_num = num;
+ 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;
}
int get_Block_dom_depth(const ir_node *bl) {
assert(get_irn_op(bl) == op_Block);
- return bl->attr.block.dom.dom_depth;
+ return get_dom_info(bl)->dom_depth;
}
void set_Block_dom_depth(ir_node *bl, int depth) {
assert(get_irn_op(bl) == op_Block);
- bl->attr.block.dom.dom_depth = depth;
+ 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;
+}
+
+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;
+}
+
+int get_Block_postdom_depth(const ir_node *bl) {
+ assert(get_irn_op(bl) == op_Block);
+ 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;
}
unsigned get_Block_dom_tree_pre_num(const ir_node *bl)
return get_dom_info(bl)->max_subtree_pre_num;
}
+unsigned get_Block_pdom_tree_pre_num(const ir_node *bl)
+{
+ assert(is_Block(bl));
+ return get_pdom_info(bl)->tree_pre_num;
+}
+
+unsigned get_Block_pdom_max_subtree_pre_num(const ir_node *bl)
+{
+ assert(is_Block(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;
return 0;
}
+/* Get the first node in the list of nodes dominated by a given block. */
ir_node *get_Block_dominated_first(const ir_node *bl)
{
assert(is_Block(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;
+
+ if (is_Block(a) && is_Block(b)) {
+ ai = get_pdom_info(a);
+ bi = get_pdom_info(b);
+ return bi->tree_pre_num - ai->tree_pre_num
+ <= ai->max_subtree_pre_num - ai->tree_pre_num;
+ }
+
+ return 0;
+}
+
+/* Get the first node in the list of nodes post dominated by a given block. */
+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)
{
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)
+ pre(bl, env);
+
+ postdominates_for_each(bl, p) {
+ postdom_tree_walk(p, pre, post, env);
+ }
+
+ 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 node. */
+ /* 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
dom_tree_walk(root, pre, post, env);
}
-static void assign_tree_pre_order(ir_node *bl, void *data)
+/* 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. */
+ ir_node *root = get_irg_end_block(irg);
+
+ assert(irg->pdom_state == dom_consistent
+ && "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
+ && "The End block node in the graph must be the root of the post dominator tree");
+ postdom_tree_walk(root, pre, post, env);
+}
+
+
+static void assign_tree_dom_pre_order(ir_node *bl, void *data)
{
unsigned *num = data;
dom_info *bi = get_dom_info(bl);
bi->tree_pre_num = (*num)++;
}
-static void assign_tree_pre_order_max(ir_node *bl, void *data)
+static void assign_tree_dom_pre_order_max(ir_node *bl, void *data)
{
dom_info *bi = get_dom_info(bl);
ir_node *p;
assert(bi->max_subtree_pre_num >= bi->tree_pre_num);
}
+static void assign_tree_postdom_pre_order(ir_node *bl, void *data)
+{
+ unsigned *num = data;
+ 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_node *p;
+ unsigned max = 0;
+ unsigned children = 0;
+
+ 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++;
+ }
+
+ bi->max_subtree_pre_num = children > 0 ? max : bi->tree_pre_num;
+ assert(bi->max_subtree_pre_num >= bi->tree_pre_num);
+}
+
/*--------------------------------------------------------------------*/
/* Building and Removing the dominator datastructure */
/*--------------------------------------------------------------------*/
-static void count_and_init_blocks(ir_node *bl, void *env) {
+/**
+ * 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) ++;
memset(get_dom_info(bl), 0, sizeof(dom_info));
set_Block_idom(bl, NULL);
- set_Block_pre_num(bl, -1);
+ set_Block_dom_pre_num(bl, -1);
set_Block_dom_depth(bl, -1);
}
-/* temporary type used while constructing the dominator tree. */
+/**
+ * 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) ++;
+
+ 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);
+}
+
+/** temporary type used while constructing the dominator / post dominator tree. */
typedef struct tmp_dom_info {
- ir_node *block; /* backlink */
+ ir_node *block; /**< backlink */
- struct tmp_dom_info *semi; /* semidominator */
+ 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 */
+ 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. */
+/** Struct to pass info through walker. */
typedef struct {
tmp_dom_info *d;
int used;
-
} dom_env;
-/* Walks Blocks along the out datastructure. If recursion started with
- Start block misses control dead blocks. */
+/**
+ * Walks Blocks along the out datastructure. If recursion started with
+ * 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;
if (get_irg_block_visited(current_ir_graph) == get_Block_block_visited(bl))
return;
mark_Block_block_visited(bl);
- set_Block_pre_num(bl, *used);
+ set_Block_dom_pre_num(bl, *used);
tdi = &tdi_list[*used];
++(*used);
}
}
-static void
-dom_compress (tmp_dom_info *v)
+/**
+ * Walks Blocks along the control flow. If recursion started with
+ * 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(get_irn_op(bl) == op_Block);
+ 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 = 0; i < get_Block_n_cfgpreds(bl); 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);
+ }
+}
+
+static void dom_compress(tmp_dom_info *v)
{
assert (v->ancestor);
if (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)
+/**
+ * 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)
{
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)
+/** make V W's ancestor */
+INLINE static void dom_link(tmp_dom_info *v, tmp_dom_info *w)
{
w->ancestor = v;
}
/* Count the number of blocks in the graph. */
n_blocks = 0;
- irg_block_walk(get_irg_end(current_ir_graph), count_and_init_blocks, NULL, &n_blocks);
+ irg_block_walk(get_irg_end(current_ir_graph), count_and_init_blocks_dom, NULL, &n_blocks);
/* Memory for temporary information. */
tdi_list = xcalloc(n_blocks, sizeof(tdi_list[0]));
ir_node *pred = get_Block_cfgpred_block(w->block, j);
tmp_dom_info *u;
- if (is_Bad(pred) || (get_Block_pre_num (pred) == -1))
- continue; /* control-dead */
+ if (is_Bad(pred) || (get_Block_dom_pre_num (pred) == -1))
+ continue; /* control-dead */
- u = dom_eval (&tdi_list[get_Block_pre_num(pred)]);
+ 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
u = dom_eval (v);
if (u->semi < v->semi)
- v->dom = u;
+ v->dom = u;
else
- v->dom = w->parent;
+ v->dom = w->parent;
}
}
/* Step 4 */
}
/* clean up */
- /* free(tdi_list); @@@ does not work !!?? */
+ 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_pre_order,
- assign_tree_pre_order_max, &tree_pre_order);
- }
+ /* 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_and_peace(ir_graph *irg) {
+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(current_ir_graph) != phase_building);
+ current_ir_graph->pdom_state = dom_consistent;
+
+ /* Count the number of blocks in the graph. */
+ n_blocks = 0;
+ irg_block_walk(get_irg_end(current_ir_graph), count_and_init_blocks_pdom, NULL, &n_blocks);
+
+ /* Memory for temporary information. */
+ tdi_list = xcalloc(n_blocks, sizeof(tdi_list[0]));
+
+ /* We need the out datastructure. */
+ if (current_ir_graph->outs_state != outs_consistent)
+ compute_irg_outs(current_ir_graph);
+
+ /* this with a standard walker as passing the parent to the sons isn't
+ simple. */
+ used = 0;
+ inc_irg_block_visited(current_ir_graph);
+ init_tmp_pdom_info(get_irg_end_block(current_ir_graph), 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);
+ current_ir_graph = 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... */
+}
*/
/**
-* @file irdom.h
-*
-* This file contains routines to construct and access dominator information.
-*
-* The dominator information is stored in three fields of block nodes:
-* - idom: a reference to the block that is the immediate dominator of
-* this block.
-* - dom_depth: a number giving the depth of the block in the dominator
-* tree.
-* - pre_num: Number in preorder traversal.
-*
-* @author Goetz Lindenmaier
-*/
-
-
-# ifndef _IRDOM_H_
-# define _IRDOM_H_
+ * @file irdom.h
+ *
+ * This file contains routines to construct and access dominator information.
+ *
+ * The dominator information is stored in three fields of block nodes:
+ * - idom: a reference to the block that is the immediate dominator of
+ * this block.
+ * - dom_depth: a number giving the depth of the block in the dominator
+ * tree.
+ * - pre_num: Number in preorder traversal.
+ *
+ * @author Goetz Lindenmaier
+ */
+#ifndef _IRDOM_H_
+#define _IRDOM_H_
-# include "irgraph.h"
-# include "irgwalk.h"
-# include "irnode.h"
+#include "firm_types.h"
/** Accessing the dominator data structure.
int get_Block_dom_depth(const ir_node *bl);
void set_Block_dom_depth(ir_node *bl, int depth);
-int get_Block_pre_num(const ir_node *bl);
-void set_Block_pre_num(ir_node *bl, int num);
+int get_Block_dom_pre_num(const ir_node *bl);
+void set_Block_dom_pre_num(ir_node *bl, int num);
+
+/** Accessing the post dominator data structure.
+ *
+ * These routines only work properly if the ir_graph is in state
+ * dom_consistent or dom_inconsistent.
+ *
+ * If the block is not reachable from End, returns a Bad node.
+ */
+ir_node *get_Block_ipostdom(const ir_node *bl);
+void set_Block_ipostdom(ir_node *bl, ir_node *n);
+
+int get_Block_postdom_depth(const ir_node *bl);
+void set_Block_postdom_depth(ir_node *bl, int depth);
+
+int get_Block_postdom_pre_num(const ir_node *bl);
+void set_Block_postdom_pre_num(ir_node *bl, int num);
/**
* Get the pre-order number of a block resulting from a
for(curr = get_Block_dominated_first(bl); curr; \
curr = get_Block_dominated_next(curr))
+/**
+ * Iterate over all nodes which are immediately post dominated by a given
+ * node.
+ * @param bl The block whose post dominated blocks shall be iterated on.
+ * @param curr An iterator variable of type ir_node*
+ */
+#define postdominates_for_each(bl,curr) \
+ for(curr = get_Block_postdominated_first(bl); curr; \
+ curr = get_Block_postdominated_next(curr))
+
/**
* Check, if a block dominates another block.
* @param a The first block.
*/
int block_dominates(const ir_node *a, const ir_node *b);
+/**
+ * Check, if a block post dominates another block.
+ * @param a The first block.
+ * @param b The second block.
+ * @return 1, if @p a post dominates @p b, else 0.
+ */
+int block_postdominates(const ir_node *a, const ir_node *b);
+
/**
* Visit all nodes in the dominator subtree of a given node.
* Call a pre-visitor before descending to the children and call a
void dom_tree_walk(ir_node *n, irg_walk_func *pre,
irg_walk_func *post, void *env);
+/**
+ * Visit all nodes in the post dominator subtree of a given node.
+ * Call a pre-visitor before descending to the children and call a
+ * post-visitor after returning from them.
+ * @param n The node to start walking from.
+ * @param pre The pre-visitor callback.
+ * @param post The post-visitor callback.
+ * @param env Some custom data passed to the visitors.
+ */
+void postdom_tree_walk(ir_node *n, irg_walk_func *pre,
+ irg_walk_func *post, void *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);
+/**
+ * Walk over the post dominator tree of an irg starting at the root.
+ * @param irg The graph.
+ * @param pre A pre-visitor to call.
+ * @param post A post-visitor to call.
+ * @param env Some private data to give to the visitors.
+ */
+void postdom_tree_walk_irg(ir_graph *irg, irg_walk_func *pre,
+ irg_walk_func *post, void *env);
+
/* ------------ Building and Removing the dominator data structure ----------- */
/** Computes the dominator trees.
*/
void compute_doms(ir_graph *irg);
+/** 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".
+ * Does not compute post dominator information for endless lops. Blocks
+ * not reachable from End contain the following information:
+ * @code
+ * idom = NULL;
+ * dom_depth = -1;
+ * pre_num = -1;
+ * @endcode
+ * Also constructs outs information. As this information is correct after
+ * the run does not free the outs information.
+ */
+void compute_postdoms(ir_graph *irg);
+
/** Frees the dominator data structures. Sets the flag in irg to "dom_none". */
-void free_dom_and_peace(ir_graph *irg);
+void free_dom(ir_graph *irg);
+
+/** Frees the post dominator data structures. Sets the flag in irg to "dom_none". */
+void free_postdom(ir_graph *irg);
#endif /* _IRDOM_H_ */
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