X-Git-Url: http://nsz.repo.hu/git/?a=blobdiff_plain;f=ir%2Fbe%2Fbelower.c;h=7ba31cfbe35cac05d31a60ca1ae93dd31b8b00f4;hb=a286e7dcdb4c41b2165c64fc85ed9eb021c08bc0;hp=45ea686bc1df9e65207d2d6a2b0fbd3be0199c11;hpb=5e1f95efc1491481487ba22482422b6d6f42bcdb;p=libfirm

diff --git a/ir/be/belower.c b/ir/be/belower.c
index 45ea686bc..7ba31cfbe 100644
--- a/ir/be/belower.c
+++ b/ir/be/belower.c
@@ -1,11 +1,28 @@
-/**
- * Author:      Christian Wuerdig
- * Date:        2005/12/14
- * Copyright:   (c) Universitaet Karlsruhe
- * Licence:     This file protected by GPL -  GNU GENERAL PUBLIC LICENSE.
- * CVS-Id:      $Id$
+/*
+ * Copyright (C) 1995-2007 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.
  *
- * Performs lowering of perm nodes and spill/reload optimization.
+ * 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       Performs lowering of perm nodes. Inserts copies to assure register constraints.
+ * @author      Christian Wuerdig
+ * @date        14.12.2005
+ * @version     $Id$
  */
 #ifdef HAVE_CONFIG_H
 #include "config.h"
@@ -15,34 +32,45 @@
 
 #include "ircons.h"
 #include "debug.h"
-
-#include "bearch.h"
-#include "belower.h"
-#include "benode_t.h"
-#include "bechordal_t.h"
-#include "besched_t.h"
-
+#include "irhooks.h"
+#include "xmalloc.h"
+#include "irnodeset.h"
 #include "irgmod.h"
 #include "iredges_t.h"
 #include "irgwalk.h"
 
-#ifdef _WIN32
-#include <malloc.h>
-#else
-#include <alloca.h>
-#endif
-
-#undef is_Perm
-#define is_Perm(arch_env, irn) (arch_irn_classify(arch_env, irn) == arch_irn_class_perm)
-
-#undef is_Call
-#define is_Call(arch_env, irn) (arch_irn_classify(arch_env, irn) == arch_irn_class_call)
+#include "bearch_t.h"
+#include "belower.h"
+#include "benode_t.h"
+#include "besched_t.h"
+#include "bestat.h"
+#include "bessaconstr.h"
+#include "benodesets.h"
+#include "beintlive_t.h"
+
+#undef KEEP_ALIVE_COPYKEEP_HACK
+
+/* associates op with it's copy and CopyKeep */
+typedef struct {
+	ir_node *op;         /* an irn which must be different */
+	ir_nodeset_t copies; /* all non-spillable copies of this irn */
+	const arch_register_class_t *cls;
+} op_copy_assoc_t;
+
+/* environment for constraints */
+typedef struct {
+	be_irg_t       *birg;
+	pset           *op_set;
+	struct obstack obst;
+	DEBUG_ONLY(firm_dbg_module_t *dbg;)
+} constraint_env_t;
 
 /* lowering walker environment */
 typedef struct _lower_env_t {
-	be_chordal_env_t  *chord_env;
-	int                do_copy;
-	firm_dbg_module_t *dbg_module;
+	be_irg_t         *birg;
+	const arch_env_t *arch_env;
+	unsigned          do_copy : 1;
+	DEBUG_ONLY(firm_dbg_module_t *dbg_module;)
 } lower_env_t;
 
 /* holds a perm register pair */
@@ -70,6 +98,15 @@ typedef struct _perm_cycle_t {
 	perm_type_t             type;        /**< type (CHAIN or CYCLE) */
 } perm_cycle_t;
 
+//
+/* Compare the two operands */
+static int cmp_op_copy_assoc(const void *a, const void *b) {
+	const op_copy_assoc_t *op1 = a;
+	const op_copy_assoc_t *op2 = b;
+
+	return op1->op != op2->op;
+}
+
 /* Compare the in registers of two register pairs */
 static int compare_reg_pair(const void *a, const void *b) {
 	const reg_pair_t *pair_a = a;
@@ -245,21 +282,24 @@ static perm_cycle_t *get_perm_cycle(perm_cycle_t *cycle, reg_pair_t *pairs, int
  * @param walk_env The environment
  */
 static void lower_perm_node(ir_node *irn, void *walk_env) {
+	ir_graph        *irg = get_irn_irg(irn);
 	const arch_register_class_t *reg_class;
 	const arch_env_t            *arch_env;
-	firm_dbg_module_t           *mod;
-	lower_env_t     *env = walk_env;
+	lower_env_t     *env         = walk_env;
+	int             real_size    = 0;
+	int             keep_perm    = 0;
+	int             n, i, pn, do_copy, j, n_ops;
 	reg_pair_t      *pairs;
 	const ir_edge_t *edge;
 	perm_cycle_t    *cycle;
-	int              n, i, pn, do_copy, j;
 	ir_node         *sched_point, *block, *in[2];
 	ir_node         *arg1, *arg2, *res1, *res2;
 	ir_node         *cpyxchg = NULL;
+	DEBUG_ONLY(firm_dbg_module_t *mod;)
 
-	arch_env = env->chord_env->birg->main_env->arch_env;
+	arch_env = env->arch_env;
 	do_copy  = env->do_copy;
-	mod      = env->dbg_module;
+	DEBUG_ONLY(mod = env->dbg_module;)
 	block    = get_nodes_block(irn);
 
 	/*
@@ -269,6 +309,7 @@ static void lower_perm_node(ir_node *irn, void *walk_env) {
 			should be ok.
 	*/
 	sched_point = sched_prev(irn);
+	DBG((mod, LEVEL_1, "perm: %+F\n", irn));
 	DBG((mod, LEVEL_1, "sched point is %+F\n", sched_point));
 	assert(sched_point && "Perm is not scheduled or has no predecessor");
 
@@ -305,15 +346,14 @@ static void lower_perm_node(ir_node *irn, void *walk_env) {
 			/* We have to check for a special case:
 				The in-node could be a Proj from a Perm. In this case,
 				we need to correct the projnum */
-			if (is_Perm(arch_env, pairs[i].in_node) && is_Proj(pairs[i].in_node)) {
+			if (be_is_Perm(pairs[i].in_node) && is_Proj(pairs[i].in_node)) {
 				set_Proj_proj(pairs[i].out_node, get_Proj_proj(pairs[i].in_node));
 			}
 
-			/* remove the proj from the schedule */
-			sched_remove(pairs[i].out_node);
-
 			/* reroute the edges from the proj to the argument */
-			edges_reroute(pairs[i].out_node, pairs[i].in_node, env->chord_env->irg);
+			exchange(pairs[i].out_node, pairs[i].in_node);
+			//edges_reroute(pairs[i].out_node, pairs[i].in_node, env->birg->irg);
+			//set_irn_n(pairs[i].out_node, 0, new_Bad());
 
 			pairs[i].checked = 1;
 		}
@@ -324,9 +364,13 @@ static void lower_perm_node(ir_node *irn, void *walk_env) {
 		do_copy = 0;
 	}
 
+	real_size = n - get_n_checked_pairs(pairs, n);
+
+	be_do_stat_perm(reg_class->name, reg_class->n_regs, irn, block, n, real_size);
+
 	/* check for cycles and chains */
 	while (get_n_checked_pairs(pairs, n) < n) {
-		i = 0;
+		i = n_ops = 0;
 
 		/* go to the first not-checked pair */
 		while (pairs[i].checked) i++;
@@ -339,11 +383,14 @@ static void lower_perm_node(ir_node *irn, void *walk_env) {
 		}
 		DB((mod, LEVEL_1, "\n"));
 
-		/* We don't need to do anything if we have a Perm with two
+		/*
+			We don't need to do anything if we have a Perm with two
 			elements which represents a cycle, because those nodes
-			already represent exchange nodes */
+			already represent exchange nodes
+		*/
 		if (n == 2 && cycle->type == PERM_CYCLE) {
 			free(cycle);
+			keep_perm = 1;
 			continue;
 		}
 
@@ -357,7 +404,6 @@ static void lower_perm_node(ir_node *irn, void *walk_env) {
 
 			res1 = get_node_for_register(pairs, n, cycle->elems[i], 1);
 			res2 = get_node_for_register(pairs, n, cycle->elems[i + 1], 1);
-
 			/*
 				If we have a cycle and don't copy: we need to create exchange nodes
 				NOTE: An exchange node is a perm node with 2 INs and 2 OUTs
@@ -402,150 +448,600 @@ static void lower_perm_node(ir_node *irn, void *walk_env) {
 				DBG((mod, LEVEL_1, "%+F                        (%+F, %s) and (%+F, %s)\n",
 					irn, res1, cycle->elems[i]->name, res2, cycle->elems[i + 1]->name));
 
-				cpyxchg = be_new_Perm(reg_class, env->chord_env->irg, block, 2, in);
+				cpyxchg = be_new_Perm(reg_class, irg, block, 2, in);
+				n_ops++;
 
 				if (i > 0) {
 					/* cycle is not done yet */
 					int pidx = get_pairidx_for_regidx(pairs, n, cycle->elems[i]->index, 0);
 
 					/* create intermediate proj */
-					res2 = new_r_Proj(get_irn_irg(irn), block, cpyxchg, get_irn_mode(res1), 0);
+					res1 = new_r_Proj(irg, block, cpyxchg, get_irn_mode(res1), 0);
 
 					/* set as in for next Perm */
-					pairs[pidx].in_node = res2;
+					pairs[pidx].in_node = res1;
 				}
-				else {
-					sched_remove(res2);
-				}
-
-				sched_remove(res1);
 
 				set_Proj_pred(res2, cpyxchg);
 				set_Proj_proj(res2, 0);
 				set_Proj_pred(res1, cpyxchg);
 				set_Proj_proj(res1, 1);
 
-				sched_add_after(sched_point, res1);
-				sched_add_after(sched_point, res2);
-
 				arch_set_irn_register(arch_env, res2, cycle->elems[i + 1]);
 				arch_set_irn_register(arch_env, res1, cycle->elems[i]);
+
+				/* insert the copy/exchange node in schedule after the magic schedule node (see above) */
+				sched_add_after(sched_point, cpyxchg);
+
+				DBG((mod, LEVEL_1, "replacing %+F with %+F, placed new node after %+F\n", irn, cpyxchg, sched_point));
+
+				/* set the new scheduling point */
+				sched_point = res1;
 			}
 			else {
 				DBG((mod, LEVEL_1, "%+F creating copy node (%+F, %s) -> (%+F, %s)\n",
 					irn, arg1, cycle->elems[i]->name, res2, cycle->elems[i + 1]->name));
 
-				cpyxchg = be_new_Copy(reg_class, env->chord_env->irg, block, arg1);
+				cpyxchg = be_new_Copy(reg_class, irg, block, arg1);
 				arch_set_irn_register(arch_env, cpyxchg, cycle->elems[i + 1]);
-
-				/* remove the proj from the schedule */
-				sched_remove(res2);
+				n_ops++;
 
 				/* exchange copy node and proj */
 				exchange(res2, cpyxchg);
-			}
 
-			/* insert the copy/exchange node in schedule after the magic schedule node (see above) */
-			sched_add_after(sched_point, cpyxchg);
-			/* set the new scheduling point */
-			sched_point = cpyxchg;
+				/* insert the copy/exchange node in schedule after the magic schedule node (see above) */
+				sched_add_after(sched_point, cpyxchg);
 
-			DBG((mod, LEVEL_1, "replacing %+F with %+F, placed new node after %+F\n", irn, cpyxchg, sched_point));
+				/* set the new scheduling point */
+				sched_point = cpyxchg;
+			}
 		}
 
+		be_do_stat_permcycle(reg_class->name, irn, block, cycle->type == PERM_CHAIN, cycle->n_elems, n_ops);
+
 		free((void *) cycle->elems);
 		free(cycle);
 	}
 
 	/* remove the perm from schedule */
-	sched_remove(irn);
+	if (! keep_perm) {
+		sched_remove(irn);
+		be_kill_node(irn);
+	}
 }
 
 
 
-/**
- * Calls the backend code generator functions to lower Spill and
- * Reload nodes into Store and Load. The backend is fully responsible
- * for creating the new nodes and setting their input correct.
- * Note: The caller of this has to make sure that irn is a Spill
- *       or Reload!
- *
- * @param irn      The Spill/Reload node
- * @param walk_env The walker environment
- */
-static void lower_spill_reload(ir_node *irn, void *walk_env) {
-	lower_env_t           *env  = walk_env;
-	arch_code_generator_t *cg   = env->chord_env->birg->cg;
-	const arch_env_t      *aenv = env->chord_env->birg->main_env->arch_env;
-	ir_node               *res  = NULL;
-	ir_node               *sched_point;
-
-	if (be_is_Spill(irn) && cg->impl->lower_spill) {
-		res = cg->impl->lower_spill(cg, irn);
+static int get_n_out_edges(const ir_node *irn) {
+	const ir_edge_t *edge;
+	int cnt = 0;
+
+	foreach_out_edge(irn, edge) {
+		cnt++;
 	}
-	else if (be_is_Reload(irn) && cg->impl->lower_reload) {
-		res = cg->impl->lower_reload(cg, irn);
-		if (res && res != irn) {
-			/* copy the result register from the reload to the load */
-			arch_set_irn_register(aenv, res, arch_get_irn_register(aenv, irn));
-		}
+
+	return cnt;
+}
+
+static INLINE ir_node *belower_skip_proj(ir_node *irn) {
+	while(is_Proj(irn))
+		irn = get_Proj_pred(irn);
+	return irn;
+}
+
+static ir_node *find_copy(constraint_env_t *env, ir_node *irn, ir_node *op) {
+	const arch_env_t *arch_env = be_get_birg_arch_env(env->birg);
+	ir_node          *block    = get_nodes_block(irn);
+	ir_node          *cur_node;
+
+	for (cur_node = sched_prev(irn);
+		! is_Block(cur_node) && be_is_Copy(cur_node) && get_nodes_block(cur_node) == block;
+		cur_node = sched_prev(cur_node))
+	{
+		if (be_get_Copy_op(cur_node) == op && arch_irn_is(arch_env, cur_node, dont_spill))
+			return cur_node;
 	}
 
-	if (res && res != irn) {
-		sched_point = sched_prev(irn);
-		sched_remove(irn);
-		exchange(irn, res);
-		sched_add_after(sched_point, res);
+	return NULL;
+}
+
+static void gen_assure_different_pattern(ir_node *irn, ir_node *other_different, constraint_env_t *env) {
+	be_irg_t                    *birg     = env->birg;
+	ir_graph                    *irg      = be_get_birg_irg(birg);
+	pset                        *op_set   = env->op_set;
+	const arch_env_t            *arch_env = be_get_birg_arch_env(birg);
+	ir_node                     *block    = get_nodes_block(irn);
+	const arch_register_class_t *cls      = arch_get_irn_reg_class(arch_env, other_different, -1);
+	ir_node                     *in[2], *keep, *cpy;
+	op_copy_assoc_t             key, *entry;
+	DEBUG_ONLY(firm_dbg_module_t *mod     = env->dbg;)
+
+	if (arch_irn_is(arch_env, other_different, ignore) || ! mode_is_datab(get_irn_mode(other_different))) {
+		DBG((mod, LEVEL_1, "ignore constraint for %+F because other_irn is ignore or not a datab node\n", irn));
+		return;
+	}
+
+	/* Make a not spillable copy of the different node   */
+	/* this is needed because the different irn could be */
+	/* in block far far away                             */
+	/* The copy is optimized later if not needed         */
+
+	/* check if already exists such a copy in the schedule immediatly before */
+	cpy = find_copy(env, belower_skip_proj(irn), other_different);
+	if (! cpy) {
+		cpy = be_new_Copy(cls, irg, block, other_different);
+		be_node_set_flags(cpy, BE_OUT_POS(0), arch_irn_flags_dont_spill);
+		DBG((mod, LEVEL_1, "created non-spillable %+F for value %+F\n", cpy, other_different));
 	}
 	else {
-		DBG((env->dbg_module, LEVEL_1, "node %+F not lowered\n", irn));
+		DBG((mod, LEVEL_1, "using already existing %+F for value %+F\n", cpy, other_different));
 	}
 
-	return;
+	in[0] = irn;
+	in[1] = cpy;
+
+	/* Add the Keep resp. CopyKeep and reroute the users */
+	/* of the other_different irn in case of CopyKeep.   */
+	if (get_n_out_edges(other_different) == 0) {
+		keep = be_new_Keep(cls, irg, block, 2, in);
+	}
+	else {
+		keep = be_new_CopyKeep_single(cls, irg, block, cpy, irn, get_irn_mode(other_different));
+		be_node_set_reg_class(keep, 1, cls);
+	}
+
+	DBG((mod, LEVEL_1, "created %+F(%+F, %+F)\n\n", keep, irn, cpy));
+
+	/* insert copy and keep into schedule */
+	assert(sched_is_scheduled(irn) && "need schedule to assure constraints");
+	if (! sched_is_scheduled(cpy))
+		sched_add_before(belower_skip_proj(irn), cpy);
+	sched_add_after(irn, keep);
+
+	/* insert the other different and it's copies into the set */
+	key.op         = other_different;
+	entry          = pset_find(op_set, &key, nodeset_hash(other_different));
+
+	if (! entry) {
+		entry         = obstack_alloc(&env->obst, sizeof(*entry));
+		ir_nodeset_init(&entry->copies);
+		entry->op     = other_different;
+		entry->cls    = cls;
+	}
+
+	/* insert copy */
+	ir_nodeset_insert(&entry->copies, cpy);
+
+	/* insert keep in case of CopyKeep */
+	if (be_is_CopyKeep(keep)) {
+		ir_nodeset_insert(&entry->copies, keep);
+	}
+
+	pset_insert(op_set, entry, nodeset_hash(other_different));
+}
+
+/**
+ * Checks if node has a should_be_different constraint in output
+ * and adds a Keep then to assure the constraint.
+ */
+static void assure_different_constraints(ir_node *irn, constraint_env_t *env) {
+	const arch_register_req_t *req;
+	const arch_env_t          *arch_env = be_get_birg_arch_env(env->birg);
+
+	req = arch_get_register_req(arch_env, irn, -1);
+
+	if (arch_register_req_is(req, should_be_different)) {
+		ir_node *different_from = get_irn_n(belower_skip_proj(irn), req->other_different);
+		gen_assure_different_pattern(irn, different_from, env);
+	} else if (arch_register_req_is(req, should_be_different_from_all)) {
+		int i, n = get_irn_arity(belower_skip_proj(irn));
+		for (i = 0; i < n; i++) {
+			gen_assure_different_pattern(irn, get_irn_n(belower_skip_proj(irn), i), env);
+		}
+	}
 }
 
 
 
 /**
- * Calls the corresponding lowering function for the node.
+ * Calls the functions to assure register constraints.
  *
  * @param irn      The node to be checked for lowering
  * @param walk_env The walker environment
  */
-static void lower_nodes_after_ra_walker(ir_node *irn, void *walk_env) {
-	lower_env_t      *env      = walk_env;
-	const arch_env_t *arch_env = env->chord_env->birg->main_env->arch_env;
+static void assure_constraints_walker(ir_node *irn, void *walk_env) {
+	if (is_Block(irn))
+		return;
+
+	if (sched_is_scheduled(irn) && mode_is_datab(get_irn_mode(irn)))
+		assure_different_constraints(irn, walk_env);
+
+	return;
+}
 
-	if (!is_Block(irn) && !is_Proj(irn)) {
-		if (is_Perm(arch_env, irn)) {
-			lower_perm_node(irn, walk_env);
+/**
+ * Melt all copykeeps pointing to the same node
+ * (or Projs of the same node), copying the same operand.
+ */
+static void melt_copykeeps(constraint_env_t *cenv) {
+	be_irg_t *birg = cenv->birg;
+	ir_graph *irg  = be_get_birg_irg(birg);
+	op_copy_assoc_t *entry;
+
+	/* for all */
+	foreach_pset(cenv->op_set, entry) {
+		int     idx, num_ck;
+		ir_node *cp;
+		struct obstack obst;
+		ir_nodeset_iterator_t iter;
+		ir_node **ck_arr, **melt_arr;
+
+		obstack_init(&obst);
+
+		/* collect all copykeeps */
+		num_ck = idx = 0;
+		foreach_ir_nodeset(&entry->copies, cp, iter) {
+			if (be_is_CopyKeep(cp)) {
+				obstack_grow(&obst, &cp, sizeof(cp));
+				++num_ck;
+			}
+#ifdef KEEP_ALIVE_COPYKEEP_HACK
+			else {
+				set_irn_mode(cp, mode_ANY);
+				keep_alive(cp);
+			}
+#endif /* KEEP_ALIVE_COPYKEEP_HACK */
 		}
-		else if (be_is_Spill(irn) || be_is_Reload(irn)) {
-			lower_spill_reload(irn, walk_env);
+
+		/* compare each copykeep with all other copykeeps */
+		ck_arr = (ir_node **)obstack_finish(&obst);
+		for (idx = 0; idx < num_ck; ++idx) {
+			ir_node *ref, *ref_mode_T;
+
+			if (ck_arr[idx]) {
+				int j, n_melt;
+				ir_node **new_ck_in;
+				ir_node *new_ck;
+				ir_node *sched_pt = NULL;
+
+				n_melt     = 1;
+				ref        = ck_arr[idx];
+				ref_mode_T = skip_Proj(get_irn_n(ref, 1));
+				obstack_grow(&obst, &ref, sizeof(ref));
+
+				DBG((cenv->dbg, LEVEL_1, "Trying to melt %+F:\n", ref));
+
+				/* check for copykeeps pointing to the same mode_T node as the reference copykeep */
+				for (j = 0; j < num_ck; ++j) {
+					ir_node *cur_ck = ck_arr[j];
+
+					if (j != idx && cur_ck && skip_Proj(get_irn_n(cur_ck, 1)) == ref_mode_T) {
+						obstack_grow(&obst, &cur_ck, sizeof(cur_ck));
+						ir_nodeset_remove(&entry->copies, cur_ck);
+						DBG((cenv->dbg, LEVEL_1, "\t%+F\n", cur_ck));
+						ck_arr[j] = NULL;
+						++n_melt;
+						sched_remove(cur_ck);
+					}
+				}
+				ck_arr[idx] = NULL;
+
+				/* check, if we found some candidates for melting */
+				if (n_melt == 1) {
+					DBG((cenv->dbg, LEVEL_1, "\tno candidate found\n"));
+					continue;
+				}
+
+				ir_nodeset_remove(&entry->copies, ref);
+				sched_remove(ref);
+
+				melt_arr = (ir_node **)obstack_finish(&obst);
+				/* melt all found copykeeps */
+				NEW_ARR_A(ir_node *, new_ck_in, n_melt);
+				for (j = 0; j < n_melt; ++j) {
+					new_ck_in[j] = get_irn_n(melt_arr[j], 1);
+
+					/* now, we can kill the melted keep, except the */
+					/* ref one, we still need some information      */
+					if (melt_arr[j] != ref)
+						be_kill_node(melt_arr[j]);
+				}
+
+#ifdef KEEP_ALIVE_COPYKEEP_HACK
+				new_ck = be_new_CopyKeep(entry->cls, irg, get_nodes_block(ref), be_get_CopyKeep_op(ref), n_melt, new_ck_in, mode_ANY);
+				keep_alive(new_ck);
+#else
+				new_ck = be_new_CopyKeep(entry->cls, irg, get_nodes_block(ref), be_get_CopyKeep_op(ref), n_melt, new_ck_in, get_irn_mode(ref));
+#endif /* KEEP_ALIVE_COPYKEEP_HACK */
+
+				/* set register class for all keeped inputs */
+				for (j = 1; j <= n_melt; ++j)
+					be_node_set_reg_class(new_ck, j, entry->cls);
+
+				ir_nodeset_insert(&entry->copies, new_ck);
+
+				/* find scheduling point */
+				if (get_irn_mode(ref_mode_T) == mode_T) {
+					/* walk along the Projs */
+					for (sched_pt = sched_next(ref_mode_T); is_Proj(sched_pt) || be_is_Keep(sched_pt) || be_is_CopyKeep(sched_pt); sched_pt = sched_next(sched_pt))
+						/* just walk along the schedule until a non-Proj/Keep/CopyKeep node is found*/ ;
+				}
+				else {
+					sched_pt = ref_mode_T;
+				}
+
+				sched_add_before(sched_pt, new_ck);
+				DBG((cenv->dbg, LEVEL_1, "created %+F, scheduled before %+F\n", new_ck, sched_pt));
+
+				/* finally: kill the reference copykeep */
+				be_kill_node(ref);
+			}
 		}
+
+		obstack_free(&obst, NULL);
 	}
+}
 
-	return;
+/**
+ * Walks over all nodes to assure register constraints.
+ *
+ * @param birg  The birg structure containing the irg
+ */
+void assure_constraints(be_irg_t *birg) {
+	ir_graph         *irg      = be_get_birg_irg(birg);
+	const arch_env_t *arch_env = be_get_birg_arch_env(birg);
+	constraint_env_t cenv;
+	op_copy_assoc_t  *entry;
+	ir_node          **nodes;
+	FIRM_DBG_REGISTER(firm_dbg_module_t *mod, "firm.be.lower.constr");
+
+	be_assure_dom_front(birg);
+
+	DEBUG_ONLY(cenv.dbg = mod;)
+	cenv.birg   = birg;
+	cenv.op_set = new_pset(cmp_op_copy_assoc, 16);
+	obstack_init(&cenv.obst);
+
+	irg_walk_blkwise_graph(irg, NULL, assure_constraints_walker, &cenv);
+
+	/* melt copykeeps, pointing to projs of */
+	/* the same mode_T node and keeping the */
+	/* same operand                         */
+	melt_copykeeps(&cenv);
+
+	/* for all */
+	foreach_pset(cenv.op_set, entry) {
+		int     n;
+		ir_node *cp;
+		ir_nodeset_iterator_t iter;
+		be_ssa_construction_env_t senv;
+
+		n     = ir_nodeset_size(&entry->copies);
+		nodes = alloca(n * sizeof(nodes[0]));
+
+		/* put the node in an array */
+		DBG((mod, LEVEL_1, "introduce copies for %+F ", entry->op));
+
+		/* collect all copies */
+		n = 0;
+		foreach_ir_nodeset(&entry->copies, cp, iter) {
+			nodes[n++] = cp;
+			DB((mod, LEVEL_1, ", %+F ", cp));
+		}
+
+		DB((mod, LEVEL_1, "\n"));
+
+		/* introduce the copies for the operand and it's copies */
+		be_ssa_construction_init(&senv, birg);
+		be_ssa_construction_add_copy(&senv, entry->op);
+		be_ssa_construction_add_copies(&senv, nodes, n);
+		be_ssa_construction_fix_users(&senv, entry->op);
+		be_ssa_construction_destroy(&senv);
+
+		/* Could be that not all CopyKeeps are really needed, */
+		/* so we transform unnecessary ones into Keeps.       */
+		foreach_ir_nodeset(&entry->copies, cp, iter) {
+			if (be_is_CopyKeep(cp) && get_irn_n_edges(cp) < 1) {
+				ir_node *keep;
+				int     n = get_irn_arity(cp);
+
+				keep = be_new_Keep(arch_get_irn_reg_class(arch_env, cp, -1),
+					irg, get_nodes_block(cp), n, (ir_node **)&get_irn_in(cp)[1]);
+				sched_add_before(cp, keep);
+
+				/* Set all ins (including the block) of the CopyKeep BAD to keep the verifier happy. */
+				sched_remove(cp);
+				be_kill_node(cp);
+			}
+		}
+
+		ir_nodeset_destroy(&entry->copies);
+	}
+
+	del_pset(cenv.op_set);
+	obstack_free(&cenv.obst, NULL);
+	be_liveness_invalidate(be_get_birg_liveness(birg));
 }
 
 
+/**
+ * Push nodes that do not need to be permed through the Perm.
+ * This is commonly a reload cascade at block ends.
+ * @note This routine needs interference.
+ * @note Probably, we can implement it a little more efficient.
+ *       Especially searching the frontier lazily might be better.
+ * @param perm The perm.
+ * @param data The walker data (lower_env_t).
+ * @return     1, if there is something left to perm over.
+ *             0, if removed the complete perm.
+ */
+static int push_through_perm(ir_node *perm, void *data)
+{
+	lower_env_t *env       = data;
+	const arch_env_t *aenv = env->arch_env;
+
+	ir_graph *irg     = get_irn_irg(perm);
+	ir_node *bl       = get_nodes_block(perm);
+	int n             = get_irn_arity(perm);
+	int *map          = alloca(n * sizeof(map[0]));
+	ir_node **projs   = alloca(n * sizeof(projs[0]));
+	bitset_t *keep    = bitset_alloca(n);
+	ir_node *frontier = sched_first(bl);
+	FIRM_DBG_REGISTER(firm_dbg_module_t *mod, "firm.be.lower.permmove");
+
+	int i, new_size, n_keep;
+	const ir_edge_t *edge;
+	ir_node *last_proj, *irn;
+	const arch_register_class_t *cls;
+
+	DBG((mod, LEVEL_1, "perm move %+F irg %+F\n", perm, irg));
+
+	/* get some proj and find out the register class of the proj. */
+	foreach_out_edge (perm, edge) {
+		last_proj  = get_edge_src_irn(edge);
+		cls = arch_get_irn_reg_class(aenv, last_proj, -1);
+		assert(is_Proj(last_proj));
+		break;
+	}
+
+	/* find the point in the schedule after which the
+	 * potentially movable nodes must be defined.
+	 * A perm will only be pushed up to first instruction
+	 * which lets an operand of itself die.  */
+
+	sched_foreach_reverse_from (sched_prev(perm), irn) {
+		for(i = get_irn_arity(irn) - 1; i >= 0; --i) {
+			ir_node *op = get_irn_n(irn, i);
+			if(arch_irn_consider_in_reg_alloc(aenv, cls, op)
+				&& !values_interfere(env->birg, op, last_proj)) {
+				frontier = sched_next(irn);
+				goto found_front;
+			}
+		}
+	}
+found_front:
+
+	DBG((mod, LEVEL_2, "\tfrontier: %+F\n", frontier));
+
+	foreach_out_edge (perm, edge) {
+		ir_node *proj  = get_edge_src_irn(edge);
+		int nr         = get_Proj_proj(proj);
+		ir_node *op    = get_irn_n(perm, nr);
+
+		assert(nr < n);
+
+		/* we will need the last Proj as an insertion point
+		 * for the instruction(s) pushed through the Perm */
+		if (sched_comes_after(last_proj, proj))
+			last_proj = proj;
+
+		projs[nr] = proj;
+
+		bitset_set(keep, nr);
+		if (!is_Proj(op) && get_nodes_block(op) == bl
+				&& (op == frontier || sched_comes_after(frontier, op))) {
+			/* don't move around nodes that modifies the flags */
+			if (arch_irn_is(aenv, op, modify_flags)) {
+				continue;
+			}
+
+			for (i = get_irn_arity(op) - 1; i >= 0; --i) {
+				ir_node *opop = get_irn_n(op, i);
+				if (!arch_irn_consider_in_reg_alloc(aenv, cls, opop)) {
+					bitset_clear(keep, nr);
+					break;
+				}
+			}
+		}
+	}
+
+	n_keep = bitset_popcnt(keep);
+
+	/* well, we could not push enything through the perm */
+	if (n_keep == n)
+		return 1;
+
+	assert(is_Proj(last_proj));
+
+	DBG((mod, LEVEL_2, "\tkeep: %d, total: %d, mask: %b\n", n_keep, n, keep));
+	last_proj = sched_next(last_proj);
+	for (new_size = 0, i = 0; i < n; ++i) {
+		ir_node *proj  = projs[i];
+
+		if (bitset_is_set(keep, i)) {
+			map[i] = new_size++;
+			set_Proj_proj(proj, map[i]);
+			DBG((mod, LEVEL_1, "\targ %d remap to %d\n", i, map[i]));
+		}
+
+		else {
+			ir_node *move = get_irn_n(perm, i);
+
+			DBG((mod, LEVEL_2, "\tmoving %+F before %+F, killing %+F\n", move, last_proj, proj));
+
+			/* move the movable node in front of the Perm */
+			sched_remove(move);
+			sched_add_before(last_proj, move);
+
+			/* give it the proj's register */
+			arch_set_irn_register(aenv, move, arch_get_irn_register(aenv, proj));
+
+			/* reroute all users of the proj to the moved node. */
+			edges_reroute(proj, move, irg);
+
+			/* and like it to bad so it is no more in the use array of the perm */
+			set_Proj_pred(proj, get_irg_bad(irg));
+
+			map[i] = -1;
+		}
+
+	}
+
+	if (n_keep > 0)
+		be_Perm_reduce(perm, new_size, map);
+
+	return n_keep > 0;
+}
+
+/**
+ * Calls the corresponding lowering function for the node.
+ *
+ * @param irn      The node to be checked for lowering
+ * @param walk_env The walker environment
+ */
+static void lower_nodes_after_ra_walker(ir_node *irn, void *walk_env) {
+	int perm_stayed;
+
+	if (is_Block(irn) || is_Proj(irn))
+		return;
+	if (!be_is_Perm(irn))
+		return;
+
+	perm_stayed = push_through_perm(irn, walk_env);
+	if (!perm_stayed)
+		return;
+
+	lower_perm_node(irn, walk_env);
+}
 
 /**
  * Walks over all blocks in an irg and performs lowering need to be
- * done after register allocation (e.g. perm and spill/reload lowering).
+ * done after register allocation (e.g. perm lowering).
  *
- * @param chord_env The chordal environment containing the irg
+ * @param birg      The birg object
  * @param do_copy   1 == resolve cycles with a free reg if available
  */
-void lower_nodes_after_ra(be_chordal_env_t *chord_env, int do_copy) {
+void lower_nodes_after_ra(be_irg_t *birg, int do_copy) {
 	lower_env_t env;
+	ir_graph    *irg = be_get_birg_irg(birg);
 
-	env.chord_env  = chord_env;
-	env.do_copy    = do_copy;
-	env.dbg_module = firm_dbg_register("firm.be.lower");
+	env.birg     = birg;
+	env.arch_env = be_get_birg_arch_env(birg);
+	env.do_copy  = do_copy;
+	FIRM_DBG_REGISTER(env.dbg_module, "firm.be.lower");
 
-	irg_walk_blkwise_graph(chord_env->irg, NULL, lower_nodes_after_ra_walker, &env);
-}
+	/* we will need interference */
+	be_liveness_assure_chk(be_get_birg_liveness(birg));
 
-#undef is_Perm
-#undef is_Call
+	irg_walk_blkwise_graph(irg, NULL, lower_nodes_after_ra_walker, &env);
+}