Remove the unused parameter const arch_env_t *env from arch_get_irn_register().
[libfirm] / ir / be / beirgmod.c
index ae92810..472d841 100644 (file)
@@ -1,18 +1,33 @@
+/*
+ * 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
- * @brief
+ * @brief       Backend IRG modification routines.
+ * @author      Sebastian Hack, Daniel Grund, Matthias Braun, Christian Wuerdig
+ * @date        04.05.2005
+ * @version     $Id$
+ *
  * This file contains the following IRG modifications for be routines:
- * - backend dominance information
- * - SSA construction for a set of nodes
  * - insertion of Perm nodes
  * - empty block elimination
  * - a simple dead node elimination (set inputs of unreachable nodes to BAD)
- *
- * @author      Sebastian Hack, Daniel Grund, Matthias Braun, Christian Wuerdig
- * @date        04.05.2005
- * @version     $Id$
- * Copyright:   (c) Universitaet Karlsruhe
- * Licence:     This file protected by GPL -  GNU GENERAL PUBLIC LICENSE.
  */
 #ifdef HAVE_CONFIG_H
 #include "config.h"
 
 #include <stdlib.h>
 
-#ifdef HAVE_MALLOC_H
- #include <malloc.h>
-#endif
-#ifdef HAVE_ALLOCA_H
- #include <alloca.h>
-#endif
-
 #include "hashptr.h"
 #include "pdeq.h"
 #include "pset.h"
@@ -34,6 +42,7 @@
 #include "util.h"
 #include "debug.h"
 #include "error.h"
+#include "xmalloc.h"
 
 #include "irflag_t.h"
 #include "ircons_t.h"
 #include "iredges_t.h"
 #include "irgraph_t.h"
 #include "irgopt.h"
+#include "irgmod.h"
 #include "irprintf_t.h"
 #include "irgwalk.h"
 
 #include "be_t.h"
 #include "bechordal_t.h"
-#include "bearch.h"
+#include "bearch_t.h"
 #include "besched_t.h"
 #include "belive_t.h"
 #include "benode_t.h"
 #include "beutil.h"
 #include "beinsn_t.h"
-
+#include "bessaconstr.h"
+#include "beirg_t.h"
 #include "beirgmod.h"
+#include "bemodule.h"
 
-DEBUG_ONLY(static firm_dbg_module_t *dbgssa = NULL;)
 DEBUG_ONLY(static firm_dbg_module_t *dbg = NULL;)
 
-/*
-  ____ ____    _
- / ___/ ___|  / \
- \___ \___ \ / _ \
-  ___) |__) / ___ \
- |____/____/_/   \_\
-   ____                _                   _   _
-  / ___|___  _ __  ___| |_ _ __ _   _  ___| |_(_) ___  _ __
- | |   / _ \| '_ \/ __| __| '__| | | |/ __| __| |/ _ \| '_ \
- | |__| (_) | | | \__ \ |_| |  | |_| | (__| |_| | (_) | | | |
-  \____\___/|_| |_|___/\__|_|   \__,_|\___|\__|_|\___/|_| |_|
-
-*/
-
-/* The problem: Given a value and a set of "copies" that are known to represent
- * the same abstract value, rewire all usages of the original value to their
- * closest copy while introducing phis as necessary.
- *
- * Algorithm: Mark all blocks in the iterated dominance frontiers of the value
- * and it's copies. Link the copies ordered by dominance to the blocks.
- * The we search for each use all all definitions in the current block, if none
- * is found, then we search one in the immediate dominator. If we are in a block
- * of the dominance frontier, create a phi and search do the same search for the
- * phi arguments.
- */
-
-/**
- * Calculates the iterated dominance frontier of a set of blocks. Marks the
- * blocks as visited. Sets the link fields of the blocks in the dominance
- * frontier to the block itself.
- */
-static
-void mark_iterated_dominance_frontiers(const be_dom_front_info_t *domfronts,
-                                       waitq *worklist)
-{
-       DBG((dbgssa, LEVEL_3, "Dominance Frontier:"));
-       while(!pdeq_empty(worklist)) {
-               int i;
-               ir_node *block = waitq_get(worklist);
-               ir_node **domfront = be_get_dominance_frontier(domfronts, block);
-               int domfront_len = ARR_LEN(domfront);
-
-               for (i = 0; i < domfront_len; ++i) {
-                       ir_node *y = domfront[i];
-                       if(Block_block_visited(y))
-                               continue;
-
-                       if(!irn_visited(y)) {
-                               set_irn_link(y, NULL);
-                               waitq_put(worklist, y);
-                       }
-                       DBG((dbgssa, LEVEL_3, " %+F", y));
-                       mark_Block_block_visited(y);
-               }
-       }
-       DBG((dbgssa, LEVEL_3, "\n"));
-}
-
-typedef struct ssa_constr_env_t {
-       ir_node **new_phis;    /**< ARR_F of newly created phis or NULL */
-       ir_mode *mode;         /**< mode of the value */
-} ssa_constr_env_t;
-
-static
-ir_node *search_def_end_of_block(ssa_constr_env_t *env, ir_node *block);
-
-static
-ir_node *create_phi(ssa_constr_env_t *env, ir_node *block, ir_node *link_with)
-{
-       int i, n_preds = get_Block_n_cfgpreds(block);
-       ir_graph *irg = get_irn_irg(block);
-       ir_node *phi;
-       ir_node **ins = alloca(n_preds * sizeof(ins[0]));
-
-       assert(n_preds > 1);
-
-       for(i = 0; i < n_preds; ++i) {
-               ins[i] = new_r_Unknown(irg, env->mode);
-       }
-       phi = new_r_Phi(irg, block, n_preds, ins, env->mode);
-       if(env->new_phis != NULL) {
-               ARR_APP1(ir_node*, env->new_phis, phi);
-       }
-
-       if(env->mode != mode_M) {
-               sched_add_after(block, phi);
-       }
-
-       DBG((dbgssa, LEVEL_2, "\tcreating phi %+F in %+F\n", phi, block));
-       set_irn_link(link_with, phi);
-       mark_irn_visited(block);
-
-       for(i = 0; i < n_preds; ++i) {
-               ir_node *pred_block = get_Block_cfgpred_block(block, i);
-               ir_node *pred_def   = search_def_end_of_block(env, pred_block);
-
-               set_irn_n(phi, i, pred_def);
-       }
-
-       return phi;
-}
-
-static
-ir_node *get_def_at_idom(ssa_constr_env_t *env, ir_node *block)
-{
-       ir_node *dom = get_Block_idom(block);
-       ir_node *def = search_def_end_of_block(env, dom);
-
-       return def;
-}
-
-static
-ir_node *search_def_end_of_block(ssa_constr_env_t *env, ir_node *block)
-{
-       if(irn_visited(block)) {
-               assert(get_irn_link(block) != NULL);
-               return get_irn_link(block);
-       } else if(Block_block_visited(block)) {
-               return create_phi(env, block, block);
-       } else {
-               ir_node *def = get_def_at_idom(env, block);
-#if 1
-               mark_irn_visited(block);
-               set_irn_link(block, def);
-#endif
-
-               return def;
-       }
-}
-
-static
-ir_node *search_def(ssa_constr_env_t *env, ir_node *at)
-{
-       ir_node *block = get_nodes_block(at);
-       ir_node *node;
-       ir_node *def;
-
-       DBG((dbgssa, LEVEL_3, "\t...searching def at %+F\n", at));
-
-       /* no defs in the current block we can do the normal searching */
-       if(!irn_visited(block) && !Block_block_visited(block)) {
-               DBG((dbgssa, LEVEL_3, "\t...continue at idom\n"));
-               return get_def_at_idom(env, block);
-       }
-
-       /* there are defs in the current block, walk the linked list to find
-          the one immediately dominating us
-        */
-       node = block;
-       def  = get_irn_link(node);
-       while(def != NULL) {
-#if 0
-               assert(get_nodes_block(def) == block);
-               if(!value_dominates_intrablock(at, def)) {
-                       DBG((dbgssa, LEVEL_3, "\t...found dominating def %+F\n", def));
-                       return def;
-               }
-#else
-               if(!value_dominates(at, def)) {
-                       DBG((dbgssa, LEVEL_3, "\t...found dominating def %+F\n", def));
-                       return def;
-               }
-#endif
-               node = def;
-               def  = get_irn_link(node);
-       }
-
-       /* block in dominance frontier? create a phi then */
-       if(Block_block_visited(block)) {
-               DBG((dbgssa, LEVEL_3, "\t...create phi at block %+F\n", block));
-               assert(!is_Phi(node));
-               return create_phi(env, block, node);
-       }
-
-
-       DBG((dbgssa, LEVEL_3, "\t...continue at idom (after checking block)\n"));
-       return get_def_at_idom(env, block);
-}
-
-/**
- * Adds a definition into the link field of the block. The definitions are
- * sorted by dominance. A non-visited block means no definition has been
- * inserted yet.
- */
-static
-void introduce_def_at_block(ir_node *block, ir_node *def)
-{
-       if(irn_visited(block)) {
-               ir_node *node = block;
-               ir_node *current_def;
-
-               while(1) {
-                       current_def = get_irn_link(node);
-                       if(current_def == def) {
-                               /* already in block */
-                               return;
-                       }
-                       if(current_def == NULL)
-                               break;
-                       if(value_dominates(current_def, def))
-                               break;
-                       node = current_def;
-               }
-
-               set_irn_link(node, def);
-               set_irn_link(def, current_def);
-       } else {
-               set_irn_link(block, def);
-               set_irn_link(def, NULL);
-               mark_irn_visited(block);
-       }
-}
-
-ir_node **be_ssa_construction(const be_dom_front_info_t *domfronts, be_lv_t *lv,
-                         ir_node *value, int copies_len, ir_node **copies,
-                         const ir_nodeset_t *ignore_uses, int need_new_phis)
-{
-       ir_graph *irg = get_irn_irg(value);
-       const ir_edge_t *edge, *next;
-       int i;
-       ir_node *block;
-       waitq *worklist;
-       ssa_constr_env_t env;
-
-       /* We need to collect the phi functions to compute their liveness. */
-       if(lv != NULL || need_new_phis) {
-               env.new_phis = NEW_ARR_F(ir_node*, 0);
-       } else {
-               env.new_phis = NULL;
-       }
-       env.mode = get_irn_mode(value);
-
-       set_using_visited(irg);
-       set_using_block_visited(irg);
-       set_using_irn_link(irg);
-
-       /* we use the visited flag to indicate blocks in the dominance frontier
-        * and blocks that already have the relevant value at the end calculated */
-       inc_irg_visited(irg);
-       /* We use the block visited flag to indicate blocks in the dominance
-        * froniter of some values (and this potentially needing phis) */
-       inc_irg_block_visited(irg);
-
-       DBG((dbgssa, LEVEL_1, "Introducing following copies for: %+F\n", value));
-       /* compute iterated dominance frontiers and create lists in the block link
-        * fields that sort usages by dominance. Blocks in the dominance frontier
-        * are marked by links back to the block. */
-       worklist = new_waitq();
-
-       block = get_nodes_block(value);
-       introduce_def_at_block(block, value);
-       waitq_put(worklist, block);
-
-       for(i = 0; i < copies_len; ++i) {
-               ir_node *copy = copies[i];
-               block = get_nodes_block(copy);
-
-               if(!irn_visited(block)) {
-                       waitq_put(worklist, block);
-               }
-               introduce_def_at_block(block, copy);
-               DBG((dbgssa, LEVEL_1, "\t%+F in %+F\n", copy, block));
-       }
-
-       mark_iterated_dominance_frontiers(domfronts, worklist);
-       del_waitq(worklist);
-
-       DBG((dbgssa, LEVEL_2, "New Definitions:\n"));
-       /*
-        * Search the valid def for each use and set it.
-        */
-       foreach_out_edge_safe(value, edge, next) {
-               ir_node *use = get_edge_src_irn(edge);
-               ir_node *at  = use;
-               int pos      = get_edge_src_pos(edge);
-
-               if(ignore_uses != NULL && ir_nodeset_contains(ignore_uses, use))
-                       continue;
-
-               if(is_Phi(use)) {
-                       ir_node *block = get_nodes_block(use);
-                       ir_node *predblock = get_Block_cfgpred_block(block, pos);
-                       at = sched_last(predblock);
-               }
-
-               ir_node *def = search_def(&env, at);
-
-               if(def == NULL) {
-                       panic("no definition found for %+F at position %d\n", use, pos);
-               }
-
-               DBG((dbgssa, LEVEL_2, "\t%+F(%d) -> %+F\n", use, pos, def));
-               set_irn_n(use, pos, def);
-       }
-
-       /* Recompute the liveness of the original nodes, the copies and the
-        * inserted phis. */
-       if(lv != NULL) {
-               int n;
-
-               be_liveness_update(lv, value);
-               for(i = 0; i < copies_len; ++i) {
-                       ir_node *copy = copies[i];
-                       be_liveness_update(lv, copy);
-               }
-
-               n = ARR_LEN(env.new_phis);
-               for(i = 0; i < n; ++i) {
-                       ir_node *phi = env.new_phis[i];
-                       be_liveness_introduce(lv, phi);
-               }
-       }
-
-       clear_using_visited(irg);
-       clear_using_block_visited(irg);
-       clear_using_irn_link(irg);
-
-       if(!need_new_phis && env.new_phis != NULL) {
-               DEL_ARR_F(env.new_phis);
-               return NULL;
-       }
-       return env.new_phis;
-}
-
-void be_ssa_constr_set_ignore(const be_dom_front_info_t *domfronts, be_lv_t *lv,
-                              pset *nodes, pset *ignores)
-{
-       ir_graph *irg;
-       const ir_edge_t *edge, *next;
-       int i;
-       ir_node *block;
-       waitq *worklist;
-       ir_node *value;
-       ssa_constr_env_t env;
-
-       foreach_pset(nodes, value) {
-               pset_break(nodes);
-               break;
-       }
-       irg = get_irn_irg(value);
-
-       /* We need to collect the phi functions to compute their liveness. */
-       if(lv != NULL) {
-               env.new_phis = NEW_ARR_F(ir_node*, 0);
-       }
-
-       set_using_visited(irg);
-       set_using_block_visited(irg);
-       set_using_irn_link(irg);
-
-       /* we use the visited flag to indicate blocks in the dominance frontier
-        * and blocks that already have the relevant value at the end calculated */
-       inc_irg_visited(irg);
-       /* We use the block visited flag to indicate blocks in the dominance
-        * froniter of some values (and this potentially needing phis) */
-       inc_irg_block_visited(irg);
-
-       DBG((dbgssa, LEVEL_1, "Introducing following copies for:\n"));
-
-       /* compute iterated dominance frontiers and create lists in the block link
-        * fields that sort usages by dominance. Blocks in the dominance frontier
-        * are marked by links back to the block. */
-       worklist = new_waitq();
-
-       foreach_pset(nodes, value) {
-               block = get_nodes_block(value);
-               env.mode = get_irn_mode(value);
-
-               if(!irn_visited(block)) {
-                       waitq_put(worklist, block);
-               }
-               introduce_def_at_block(block, value);
-               DBG((dbgssa, LEVEL_1, "\t%+F in %+F\n", value, block));
-       }
-
-       mark_iterated_dominance_frontiers(domfronts, worklist);
-       del_waitq(worklist);
-
-       /*
-        * Search the valid def for each use and set it.
-        */
-       foreach_pset(nodes, value) {
-               foreach_out_edge_safe(value, edge, next) {
-                       ir_node *use = get_edge_src_irn(edge);
-                       ir_node *at  = use;
-                       int pos      = get_edge_src_pos(edge);
-
-                       if(ignores != NULL && pset_find_ptr(ignores, use))
-                               continue;
-
-                       if(is_Phi(use)) {
-                               ir_node *block = get_nodes_block(use);
-                               ir_node *predblock = get_Block_cfgpred_block(block, pos);
-                               at = sched_last(predblock);
-                       }
-
-                       ir_node *def = search_def(&env, at);
-
-                       if(def == NULL) {
-                               panic("no definition found for %+F input %d\n", use, pos);
-                       }
-
-                       DBG((dbgssa, LEVEL_2, "\t%+F(%d) -> %+F\n", use, pos, def));
-                       set_irn_n(use, pos, def);
-               }
-       }
-
-       /* Recompute the liveness of the original nodes, the copies and the
-        * inserted phis. */
-       if(lv != NULL) {
-               int n;
-
-               foreach_pset(nodes, value) {
-                       be_liveness_update(lv, value);
-               }
-
-               n = ARR_LEN(env.new_phis);
-               for(i = 0; i < n; ++i) {
-                       ir_node *phi = env.new_phis[i];
-                       be_liveness_introduce(lv, phi);
-               }
-               DEL_ARR_F(env.new_phis);
-       }
-
-       clear_using_visited(irg);
-       clear_using_block_visited(irg);
-       clear_using_irn_link(irg);
-}
-
 /*
   ___                     _     ____
  |_ _|_ __  ___  ___ _ __| |_  |  _ \ ___ _ __ _ __ ___
@@ -499,38 +81,41 @@ void be_ssa_constr_set_ignore(const be_dom_front_info_t *domfronts, be_lv_t *lv,
 
 */
 
-ir_node *insert_Perm_after(const arch_env_t *arch_env,
-                                                  be_lv_t *lv,
+ir_node *insert_Perm_after(be_irg_t *birg,
                                                   const arch_register_class_t *cls,
-                                                  be_dom_front_info_t *dom_front,
                                                   ir_node *pos)
 {
+       const arch_env_t *arch_env = birg->main_env->arch_env;
+       be_lv_t *lv     = birg->lv;
        ir_node *bl     = is_Block(pos) ? pos : get_nodes_block(pos);
        ir_graph *irg   = get_irn_irg(bl);
-       pset *live      = pset_new_ptr_default();
+       ir_nodeset_t          live;
+       ir_nodeset_iterator_t iter;
 
        ir_node *curr, *irn, *perm, **nodes;
-       int i, n;
+       size_t i, n;
 
        DBG((dbg, LEVEL_1, "Insert Perm after: %+F\n", pos));
 
-       be_liveness_nodes_live_at(lv, arch_env, cls, pos, live);
-
-       n = pset_count(live);
+       ir_nodeset_init(&live);
+       be_liveness_nodes_live_at(lv, arch_env, cls, pos, &live);
 
+       n = ir_nodeset_size(&live);
        if(n == 0) {
-               del_pset(live);
+               ir_nodeset_destroy(&live);
                return NULL;
        }
 
-       nodes = xmalloc(n * sizeof(nodes[0]));
+       nodes = XMALLOCN(ir_node*, n);
 
        DBG((dbg, LEVEL_1, "live:\n"));
-       for(irn = pset_first(live), i = 0; irn; irn = pset_next(live), i++) {
+       i = 0;
+       foreach_ir_nodeset(&live, irn, iter) {
                DBG((dbg, LEVEL_1, "\t%+F\n", irn));
                nodes[i] = irn;
+               i++;
        }
-       del_pset(live);
+       ir_nodeset_destroy(&live);
 
        perm = be_new_Perm(cls, irg, bl, n, nodes);
        sched_add_after(pos, perm);
@@ -538,83 +123,152 @@ ir_node *insert_Perm_after(const arch_env_t *arch_env,
 
        curr = perm;
        for (i = 0; i < n; ++i) {
-               ir_node *copies[1];
                ir_node *perm_op = get_irn_n(perm, i);
-               const arch_register_t *reg = arch_get_irn_register(arch_env, perm_op);
+               const arch_register_t *reg = arch_get_irn_register(perm_op);
+               be_ssa_construction_env_t senv;
 
                ir_mode *mode = get_irn_mode(perm_op);
                ir_node *proj = new_r_Proj(irg, bl, perm, mode, i);
                arch_set_irn_register(arch_env, proj, reg);
 
-               sched_add_after(curr, proj);
                curr = proj;
 
-               copies[0] = proj;
-
-               be_ssa_construction(dom_front, lv, perm_op, 1, copies, NULL, 0);
+               be_ssa_construction_init(&senv, birg);
+               be_ssa_construction_add_copy(&senv, perm_op);
+               be_ssa_construction_add_copy(&senv, proj);
+               be_ssa_construction_fix_users(&senv, perm_op);
+               be_ssa_construction_update_liveness_phis(&senv, lv);
+               be_liveness_update(lv, perm_op);
+               be_liveness_update(lv, proj);
+               be_ssa_construction_destroy(&senv);
        }
 
        return perm;
 }
 
+static int blocks_removed;
+
 /**
  * Post-block-walker: Find blocks containing only one jump and
  * remove them.
  */
-static void remove_empty_block(ir_node *block, void *data) {
+static void remove_empty_block(ir_node *block)
+{
        const ir_edge_t *edge, *next;
+       int      i, arity;
        ir_node *node;
-       int *changed = data;
+       ir_node *pred;
+       ir_node *succ_block;
        ir_node *jump = NULL;
 
-       assert(is_Block(block));
+       if (irn_visited_else_mark(block))
+               return;
 
        if (get_Block_n_cfgpreds(block) != 1)
-               return;
+               goto check_preds;
 
        sched_foreach(block, node) {
                if (! is_Jmp(node))
-                       return;
+                       goto check_preds;
                if (jump != NULL) {
                        /* we should never have 2 jumps in a block */
-                       panic("We should never have 2 jumps in a block");
+                       panic("found 2 jumps in a block");
                }
                jump = node;
        }
 
        if (jump == NULL)
-               return;
+               goto check_preds;
 
-       node = get_Block_cfgpred(block, 0);
+       pred       = get_Block_cfgpred(block, 0);
+       succ_block = NULL;
        foreach_out_edge_safe(jump, edge, next) {
-               ir_node *block = get_edge_src_irn(edge);
-               int     pos    = get_edge_src_pos(edge);
+               int pos = get_edge_src_pos(edge);
+
+               assert(succ_block == NULL);
+               succ_block = get_edge_src_irn(edge);
 
-               set_irn_n(block, pos, node);
+               set_irn_n(succ_block, pos, pred);
+       }
+
+       /* there can be some non-scheduled Pin nodes left in the block, move them
+        * to the succ block (Pin) or pred block (Sync) */
+       foreach_out_edge_safe(block, edge, next) {
+               node = get_edge_src_irn(edge);
+
+               if(node == jump)
+                       continue;
+               if (is_Block(node)) {
+                       /* a Block->Block edge: This should be the MacroBlock
+                          edge, ignore it. */
+                       assert(get_Block_MacroBlock(node) == block && "Wrong Block->Block edge");
+                       continue;
+               }
+               if (is_Pin(node)) {
+                       set_nodes_block(node, succ_block);
+                       continue;
+               }
+               if (is_Sync(node)) {
+                       set_nodes_block(node, get_nodes_block(pred));
+                       continue;
+               }
+               if (is_End(node)) { /* End-keep, reroute it to the successor */
+                       int pos = get_edge_src_pos(edge);
+                       set_irn_n(node, pos, succ_block);
+                       continue;
+               }
+               panic("Unexpected node %+F in block %+F with empty schedule", node, block);
        }
 
        set_Block_cfgpred(block, 0, new_Bad());
-       be_kill_node(jump);
-       *changed = 1;
+       kill_node(jump);
+       blocks_removed = 1;
+
+       /* check predecessor */
+       remove_empty_block(get_nodes_block(pred));
+       return;
+
+check_preds:
+       arity = get_Block_n_cfgpreds(block);
+       for(i = 0; i < arity; ++i) {
+               ir_node *pred = get_Block_cfgpred_block(block, i);
+               remove_empty_block(pred);
+       }
 }
 
 /* removes basic blocks that just contain a jump instruction */
-int be_remove_empty_blocks(ir_graph *irg) {
-       int changed = 0;
+int be_remove_empty_blocks(ir_graph *irg)
+{
+       ir_node *end;
+       int      i, arity;
+
+       blocks_removed = 0;
+
+       ir_reserve_resources(irg, IR_RESOURCE_IRN_VISITED);
+       inc_irg_visited(irg);
+       remove_empty_block(get_irg_end_block(irg));
+       end   = get_irg_end(irg);
+       arity = get_irn_arity(end);
+       for(i = 0; i < arity; ++i) {
+               ir_node *pred = get_irn_n(end, i);
+               if(!is_Block(pred))
+                       continue;
+               remove_empty_block(pred);
+       }
+       ir_free_resources(irg, IR_RESOURCE_IRN_VISITED);
 
-       irg_block_walk_graph(irg, remove_empty_block, NULL, &changed);
-       if (changed) {
+       if (blocks_removed) {
                /* invalidate analysis info */
                set_irg_doms_inconsistent(irg);
                set_irg_extblk_inconsistent(irg);
                set_irg_outs_inconsistent(irg);
+               set_irg_loopinfo_inconsistent(irg);
        }
-       return changed;
+       return blocks_removed;
 }
 
 void be_init_irgmod(void)
 {
-       FIRM_DBG_REGISTER(dbgssa, "firm.be.ssaconstr");
        FIRM_DBG_REGISTER(dbg, "firm.be.irgmod");
 }