X-Git-Url: http://nsz.repo.hu/git/?a=blobdiff_plain;f=ir%2Fbe%2Fbespill.c;h=04c886064602fbdfe5ff48c6cd720be8ae2109c5;hb=70481aa342e22f5f285dc863b366a56393d888af;hp=079a3be510316d489934493ecd6ee6f2ed7b0ead;hpb=152a8f1c6542fa3f0d83058efe1e8767f0dd0319;p=libfirm

diff --git a/ir/be/bespill.c b/ir/be/bespill.c
index 079a3be51..04c886064 100644
--- a/ir/be/bespill.c
+++ b/ir/be/bespill.c
@@ -1,231 +1,1091 @@
+/*
+ * 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.
+ */
+
 /**
- * Author:      Daniel Grund
- * Date:		29.09.2005
- * Copyright:   (c) Universitaet Karlsruhe
- * Licence:     This file protected by GPL -  GNU GENERAL PUBLIC LICENSE.
+ * @file
+ * @brief       implementation of the spill/reload placement abstraction layer
+ * @author      Daniel Grund, Sebastian Hack, Matthias Braun
+ * @date		29.09.2005
+ * @version     $Id$
  */
+#include "config.h"
+
+#include <stdlib.h>
+#include <stdbool.h>
 
 #include "pset.h"
 #include "irnode_t.h"
 #include "ircons_t.h"
+#include "iredges_t.h"
+#include "irbackedge_t.h"
+#include "irprintf.h"
+#include "ident_t.h"
+#include "type_t.h"
+#include "entity_t.h"
 #include "debug.h"
+#include "irgwalk.h"
+#include "array.h"
+#include "pdeq.h"
+#include "execfreq.h"
+#include "irnodeset.h"
+#include "error.h"
 
-#include "besched.h"
+#include "bearch_t.h"
+#include "belive_t.h"
+#include "besched_t.h"
 #include "bespill.h"
+#include "belive_t.h"
 #include "benode_t.h"
+#include "bechordal_t.h"
+#include "bespilloptions.h"
+#include "bestatevent.h"
+#include "bessaconstr.h"
+#include "beirg_t.h"
+#include "beintlive_t.h"
+#include "bemodule.h"
+#include "be_t.h"
 
-typedef struct _reloader_t reloader_t;
-typedef struct _spill_info_t spill_info_t;
+DEBUG_ONLY(static firm_dbg_module_t *dbg = NULL;)
 
-struct _reloader_t {
+#define REMAT_COST_INFINITE  1000
+
+typedef struct reloader_t reloader_t;
+struct reloader_t {
 	reloader_t *next;
-	ir_node *reloader;
+	ir_node    *can_spill_after;
+	ir_node    *reloader;
+	ir_node    *rematted_node;
+	int         remat_cost_delta; /** costs needed for rematerialization,
+	                                   compared to placing a reload */
 };
 
-struct _spill_info_t {
-	ir_node *spilled_node;
-	reloader_t *reloaders;
+typedef struct spill_t spill_t;
+struct spill_t {
+	spill_t *next;
+	ir_node *after;  /**< spill has to be placed after this node (or earlier) */
+	ir_node *spill;
 };
 
-typedef struct _spill_ctx_t {
-	ir_node *spilled;  /**< The spilled node. */
-	ir_node *user;     /**< The node this spill is for. */
-	ir_node *spill;    /**< The spill itself. */
-} spill_ctx_t;
-
-struct _spill_env_t {
-	firm_dbg_module_t *dbg;
-	const arch_register_class_t *cls;
-	const be_main_session_env_t *session;
-	struct obstack obst;
-	set *spill_ctxs;
-	set *spills;		/**< all spill_info_t's, which must be placed */
+typedef struct spill_info_t spill_info_t;
+struct spill_info_t {
+	ir_node    *to_spill;  /**< the value that should get spilled */
+	reloader_t *reloaders; /**< list of places where the value should get
+	                            reloaded */
+	spill_t    *spills;    /**< list of latest places where spill must be
+	                            placed */
+	double      spill_costs; /**< costs needed for spilling the value */
+	const arch_register_class_t *reload_cls; /** the register class in which the
+	                                             reload should be placed */
 };
 
-static int cmp_spillctx(const void *a, const void *b, size_t n) {
-	const spill_ctx_t *p = a;
-	const spill_ctx_t *q = b;
-	return !(p->user == q->user && p->spilled == q->spilled);
-}
+struct spill_env_t {
+	const arch_env_t *arch_env;
+	ir_graph         *irg;
+	struct obstack    obst;
+	be_irg_t         *birg;
+	int               spill_cost;     /**< the cost of a single spill node */
+	int               reload_cost;    /**< the cost of a reload node */
+	set              *spills;         /**< all spill_info_t's, which must be
+	                                       placed */
+	ir_nodeset_t      mem_phis;       /**< set of all spilled phis. */
+	ir_exec_freq     *exec_freq;
 
-static int cmp_spillinfo(const void *x, const void *y, size_t size) {
+#ifdef FIRM_STATISTICS
+	unsigned          spill_count;
+	unsigned          reload_count;
+	unsigned          remat_count;
+	unsigned          spilled_phi_count;
+#endif
+};
+
+/**
+ * Compare two spill infos.
+ */
+static int cmp_spillinfo(const void *x, const void *y, size_t size)
+{
 	const spill_info_t *xx = x;
 	const spill_info_t *yy = y;
-	return ! (xx->spilled_node == yy->spilled_node);
+	(void) size;
+
+	return xx->to_spill != yy->to_spill;
 }
 
-spill_env_t *be_new_spill_env(
-		firm_dbg_module_t *dbg,
-		const be_main_session_env_t *session,
-		const arch_register_class_t *cls)
+/**
+ * Returns spill info for a specific value (the value that is to be spilled)
+ */
+static spill_info_t *get_spillinfo(const spill_env_t *env, ir_node *value)
 {
-	spill_env_t *env = malloc(sizeof(env[0]));
-	env->spill_ctxs = new_set(cmp_spillctx, 1024);
-	env->spills     = new_set(cmp_spillinfo, 1024);
-	env->session    = session;
-	env->cls        = cls;
-	env->dbg        = dbg;
+	spill_info_t info, *res;
+	int hash = hash_irn(value);
+
+	info.to_spill = value;
+	res = set_find(env->spills, &info, sizeof(info), hash);
+
+	if (res == NULL) {
+		info.reloaders   = NULL;
+		info.spills      = NULL;
+		info.spill_costs = -1;
+		info.reload_cls  = NULL;
+		res = set_insert(env->spills, &info, sizeof(info), hash);
+	}
+
+	return res;
+}
+
+spill_env_t *be_new_spill_env(be_irg_t *birg)
+{
+	const arch_env_t *arch_env = birg->main_env->arch_env;
+
+	spill_env_t *env = XMALLOC(spill_env_t);
+	env->spills			= new_set(cmp_spillinfo, 1024);
+	env->irg            = be_get_birg_irg(birg);
+	env->birg           = birg;
+	env->arch_env       = arch_env;
+	ir_nodeset_init(&env->mem_phis);
+	env->spill_cost     = arch_env->spill_cost;
+	env->reload_cost    = arch_env->reload_cost;
+	env->exec_freq      = be_get_birg_exec_freq(birg);
 	obstack_init(&env->obst);
+
+#ifdef FIRM_STATISTICS
+	env->spill_count       = 0;
+	env->reload_count      = 0;
+	env->remat_count       = 0;
+	env->spilled_phi_count = 0;
+#endif
+
 	return env;
 }
 
-void be_delete_spill_env(spill_env_t *senv)
+void be_delete_spill_env(spill_env_t *env)
 {
-	del_set(senv->spill_ctxs);
-	del_set(senv->spills);
-	obstack_free(&senv->obst, NULL);
-	free(senv);
+	del_set(env->spills);
+	ir_nodeset_destroy(&env->mem_phis);
+	obstack_free(&env->obst, NULL);
+	free(env);
 }
 
-static spill_ctx_t *be_get_spill_ctx(set *sc, ir_node *to_spill, ir_node *ctx_irn) {
-	spill_ctx_t templ;
+/*
+ *  ____  _                  ____      _                 _
+ * |  _ \| | __ _  ___ ___  |  _ \ ___| | ___   __ _  __| |___
+ * | |_) | |/ _` |/ __/ _ \ | |_) / _ \ |/ _ \ / _` |/ _` / __|
+ * |  __/| | (_| | (_|  __/ |  _ <  __/ | (_) | (_| | (_| \__ \
+ * |_|   |_|\__,_|\___\___| |_| \_\___|_|\___/ \__,_|\__,_|___/
+ *
+ */
+
+void be_add_spill(spill_env_t *env, ir_node *to_spill, ir_node *after)
+{
+	spill_info_t *spill_info = get_spillinfo(env, to_spill);
+	spill_t      *spill;
+	spill_t      *s;
+	spill_t      *last;
+
+	assert(!arch_irn_is(to_spill, dont_spill));
+	DB((dbg, LEVEL_1, "Add spill of %+F after %+F\n", to_spill, after));
+
+	/* Just for safety make sure that we do not insert the spill in front of a phi */
+	assert(!is_Phi(sched_next(after)));
+
+	/* spills that are dominated by others are not needed */
+	last = NULL;
+	s    = spill_info->spills;
+	for( ; s != NULL; s = s->next) {
+		/* no need to add this spill if it is dominated by another */
+		if(value_dominates(s->after, after)) {
+			DB((dbg, LEVEL_1, "...dominated by %+F, not added\n", s->after));
+			return;
+		}
+		/* remove spills that we dominate */
+		if(value_dominates(after, s->after)) {
+			DB((dbg, LEVEL_1, "...remove old spill at %+F\n", s->after));
+			if(last != NULL) {
+				last->next         = s->next;
+			} else {
+				spill_info->spills = s->next;
+			}
+		} else {
+			last = s;
+		}
+	}
 
-	templ.spilled = to_spill;
-	templ.user    = ctx_irn;
-	templ.spill   = NULL;
+	spill         = obstack_alloc(&env->obst, sizeof(spill[0]));
+	spill->after  = after;
+	spill->next   = spill_info->spills;
+	spill->spill  = NULL;
 
-	return set_insert(sc, &templ, sizeof(templ), HASH_COMBINE(HASH_PTR(to_spill), HASH_PTR(ctx_irn)));
+	spill_info->spills = spill;
 }
 
-static ir_node *be_spill_irn(spill_env_t *senv, ir_node *irn, ir_node *ctx_irn) {
-	spill_ctx_t *ctx;
-//	DBG((dbg, DBG_SPILL, "spill_irn %+F\n", irn));
+void be_add_remat(spill_env_t *env, ir_node *to_spill, ir_node *before,
+                  ir_node *rematted_node)
+{
+	spill_info_t *spill_info;
+	reloader_t *reloader;
+
+	spill_info = get_spillinfo(env, to_spill);
+
+	/* add the remat information */
+	reloader                   = obstack_alloc(&env->obst, sizeof(reloader[0]));
+	reloader->next             = spill_info->reloaders;
+	reloader->reloader         = before;
+	reloader->rematted_node    = rematted_node;
+	reloader->remat_cost_delta = 0; /* We will never have a cost win over a
+	                                   reload since we're not even allowed to
+	                                   create a reload */
+
+	spill_info->reloaders  = reloader;
+
+	DBG((dbg, LEVEL_1, "creating spillinfo for %+F, will be rematerialized before %+F\n",
+		to_spill, before));
+}
+
+void be_add_reload2(spill_env_t *env, ir_node *to_spill, ir_node *before,
+		ir_node *can_spill_after, const arch_register_class_t *reload_cls,
+		int allow_remat)
+{
+	spill_info_t *info;
+	reloader_t *rel;
+
+	assert(!arch_irn_is(to_spill, dont_spill));
+
+	info = get_spillinfo(env, to_spill);
+
+	if (is_Phi(to_spill)) {
+		int i, arity;
+
+		/* create spillinfos for the phi arguments */
+		for (i = 0, arity = get_irn_arity(to_spill); i < arity; ++i) {
+			ir_node *arg = get_irn_n(to_spill, i);
+			get_spillinfo(env, arg);
+		}
+	}
+
+	assert(!is_Proj(before) && !be_is_Keep(before));
 
-	ctx = be_get_spill_ctx(senv->spill_ctxs, irn, ctx_irn);
-	if(!ctx->spill) {
-		const be_main_env_t *env = senv->session->main_env;
-		ctx->spill = be_spill(env->node_factory, env->arch_env, irn);
+	/* put reload into list */
+	rel                   = obstack_alloc(&env->obst, sizeof(rel[0]));
+	rel->next             = info->reloaders;
+	rel->reloader         = before;
+	rel->rematted_node    = NULL;
+	rel->can_spill_after  = can_spill_after;
+	rel->remat_cost_delta = allow_remat ? 0 : REMAT_COST_INFINITE;
+
+	info->reloaders  = rel;
+	assert(info->reload_cls == NULL || info->reload_cls == reload_cls);
+	info->reload_cls = reload_cls;
+
+	DBG((dbg, LEVEL_1, "creating spillinfo for %+F, will be reloaded before %+F, may%s be rematerialized\n",
+		to_spill, before, allow_remat ? "" : " not"));
+}
+
+void be_add_reload(spill_env_t *senv, ir_node *to_spill, ir_node *before,
+                   const arch_register_class_t *reload_cls, int allow_remat)
+{
+	be_add_reload2(senv, to_spill, before, to_spill, reload_cls, allow_remat);
+
+}
+
+ir_node *be_get_end_of_block_insertion_point(const ir_node *block)
+{
+	ir_node *last = sched_last(block);
+
+	/* we might have keeps behind the jump... */
+	while (be_is_Keep(last)) {
+		last = sched_prev(last);
+		assert(!sched_is_end(last));
 	}
 
-	return ctx->spill;
+	assert(is_cfop(last));
+
+	/* add the reload before the (cond-)jump */
+	return last;
+}
+
+static ir_node *skip_keeps_phis(ir_node *node)
+{
+	while(true) {
+		ir_node *next = sched_next(node);
+		if(!is_Phi(next) && !be_is_Keep(next))
+			break;
+		node = next;
+	}
+	return node;
 }
 
 /**
- * If the first usage of a phi result would be out of memory
+ * Returns the point at which you can insert a node that should be executed
+ * before block @p block when coming from pred @p pos.
+ */
+static ir_node *get_block_insertion_point(ir_node *block, int pos)
+{
+	ir_node *predblock;
+
+	/* simply add the reload to the beginning of the block if we only have 1
+	 * predecessor. We don't need to check for phis as there can't be any in a
+	 * block with only 1 pred. */
+	if(get_Block_n_cfgpreds(block) == 1) {
+		assert(!is_Phi(sched_first(block)));
+		return sched_first(block);
+	}
+
+	/* We have to reload the value in pred-block */
+	predblock = get_Block_cfgpred_block(block, pos);
+	return be_get_end_of_block_insertion_point(predblock);
+}
+
+void be_add_reload_at_end(spill_env_t *env, ir_node *to_spill,
+                          const ir_node *block,
+                          const arch_register_class_t *reload_cls,
+                          int allow_remat)
+{
+	ir_node *before = be_get_end_of_block_insertion_point(block);
+	be_add_reload(env, to_spill, before, reload_cls, allow_remat);
+}
+
+void be_add_reload_on_edge(spill_env_t *env, ir_node *to_spill, ir_node *block,
+                           int pos,	const arch_register_class_t *reload_cls,
+                           int allow_remat)
+{
+	ir_node *before = get_block_insertion_point(block, pos);
+	be_add_reload(env, to_spill, before, reload_cls, allow_remat);
+}
+
+void be_spill_phi(spill_env_t *env, ir_node *node)
+{
+	ir_node *block;
+	spill_info_t* spill;
+	int i, arity;
+
+	assert(is_Phi(node));
+
+	ir_nodeset_insert(&env->mem_phis, node);
+
+	/* create spills for the phi arguments */
+	block = get_nodes_block(node);
+	spill = get_spillinfo(env, node);
+	for(i = 0, arity = get_irn_arity(node); i < arity; ++i) {
+		ir_node *arg = get_irn_n(node, i);
+		ir_node *insert;
+		//get_spillinfo(env, arg);
+
+		/* some backends have virtual noreg/unknown nodes that are not scheduled
+		 * and simply always available. */
+		if(!sched_is_scheduled(arg)) {
+			ir_node *pred_block = get_Block_cfgpred_block(block, i);
+			insert = be_get_end_of_block_insertion_point(pred_block);
+			insert = sched_prev(insert);
+		} else {
+			insert = skip_keeps_phis(arg);
+		}
+
+		be_add_spill(env, arg, insert);
+	}
+}
+
+/*
+ *   ____                _         ____        _ _ _
+ *  / ___|_ __ ___  __ _| |_ ___  / ___| _ __ (_) | |___
+ * | |   | '__/ _ \/ _` | __/ _ \ \___ \| '_ \| | | / __|
+ * | |___| | |  __/ (_| | ||  __/  ___) | |_) | | | \__ \
+ *  \____|_|  \___|\__,_|\__\___| |____/| .__/|_|_|_|___/
+ *                                      |_|
+ */
+
+static void determine_spill_costs(spill_env_t *env, spill_info_t *spillinfo);
+
+/**
+ * Creates a spill.
+ *
+ * @param senv      the spill environment
+ * @param irn       the node that should be spilled
+ * @param ctx_irn   an user of the spilled node
+ *
+ * @return a be_Spill node
+ */
+static void spill_irn(spill_env_t *env, spill_info_t *spillinfo)
+{
+	ir_node *to_spill = spillinfo->to_spill;
+	spill_t *spill;
+
+	/* determine_spill_costs must have been run before */
+	assert(spillinfo->spill_costs >= 0);
+
+	/* some backends have virtual noreg/unknown nodes that are not scheduled
+	 * and simply always available. */
+	if(!sched_is_scheduled(to_spill)) {
+		/* override spillinfos or create a new one */
+		spillinfo->spills->spill = new_NoMem();
+		DB((dbg, LEVEL_1, "don't spill %+F use NoMem\n", to_spill));
+		return;
+	}
+
+	DBG((dbg, LEVEL_1, "spilling %+F ... \n", to_spill));
+	spill = spillinfo->spills;
+	for( ; spill != NULL; spill = spill->next) {
+		ir_node *after = spill->after;
+		ir_node *block = get_block(after);
+
+		after = skip_keeps_phis(after);
+
+		spill->spill = be_spill(block, to_spill);
+		sched_add_after(after, spill->spill);
+		DB((dbg, LEVEL_1, "\t%+F after %+F\n", spill->spill, after));
+#ifdef FIRM_STATISTICS
+		env->spill_count++;
+#endif
+	}
+	DBG((dbg, LEVEL_1, "\n"));
+}
+
+static void spill_node(spill_env_t *env, spill_info_t *spillinfo);
+
+/**
+ * If the first usage of a Phi result would be out of memory
  * there is no sense in allocating a register for it.
  * Thus we spill it and all its operands to the same spill slot.
  * Therefore the phi/dataB becomes a phi/Memory
+ *
+ * @param senv      the spill environment
+ * @param phi       the Phi node that should be spilled
+ * @param ctx_irn   an user of the spilled node
  */
-static ir_node *be_spill_phi(spill_env_t *senv, ir_node *phi, ir_node *ctx_irn,
-		pset *mem_phis) {
-	int i, n = get_irn_arity(phi);
-	ir_node **ins, *bl = get_nodes_block(phi);
-	ir_graph *irg = senv->session->irg;
-	spill_ctx_t *ctx;
+static void spill_phi(spill_env_t *env, spill_info_t *spillinfo)
+{
+	ir_graph *irg   = env->irg;
+	ir_node  *phi   = spillinfo->to_spill;
+	ir_node  *block = get_nodes_block(phi);
+	ir_node  *unknown;
+	ir_node **ins;
+	spill_t  *spill;
+	int       i;
+	int       arity;
 
 	assert(is_Phi(phi));
-//	DBG((dbg, DBG_SPILL, "spill_phi %+F\n", phi));
-
-	/* search an existing spill for this context */
-	ctx = be_get_spill_ctx(senv->spill_ctxs, phi, ctx_irn);
-
-	/* if not found spill the phi */
-	if(!ctx->spill) {
-		/* build a new PhiM with dummy in-array */
-		ins  = malloc(n * sizeof(ins[0]));
-		for(i=0; i<n; ++i)
-			ins[i] = new_r_Unknown(irg, mode_M);
-		ctx->spill = new_r_Phi(senv->session->irg, bl, n, ins, mode_M);
-		free(ins);
-
-		/* re-wire the phiM */
-		for(i=0; i<n; ++i) {
-			ir_node *arg = get_irn_n(phi, i);
-			ir_node *sub_res;
-
-			if(is_Phi(arg) && pset_find_ptr(mem_phis, arg))
-				sub_res = be_spill_phi(senv, arg, ctx_irn, mem_phis);
-			else
-				sub_res = be_spill_irn(senv, arg, ctx_irn);
-
-			set_irn_n(ctx->spill, i, sub_res);
+	assert(!get_opt_cse());
+	DBG((dbg, LEVEL_1, "spilling Phi %+F:\n", phi));
+
+	/* build a new PhiM */
+	arity   = get_irn_arity(phi);
+	ins     = alloca(sizeof(ir_node*) * arity);
+	unknown = new_r_Unknown(irg, mode_M);
+	for(i = 0; i < arity; ++i) {
+		ins[i] = unknown;
+	}
+
+	/* override or replace spills list... */
+	spill         = obstack_alloc(&env->obst, sizeof(spill[0]));
+	spill->after  = skip_keeps_phis(phi);
+	spill->spill  = new_r_Phi(irg, block, arity, ins, mode_M);
+	spill->next   = NULL;
+
+	spillinfo->spills = spill;
+#ifdef FIRM_STATISTICS
+	env->spilled_phi_count++;
+#endif
+
+	for(i = 0; i < arity; ++i) {
+		ir_node      *arg      = get_irn_n(phi, i);
+		spill_info_t *arg_info = get_spillinfo(env, arg);
+
+		determine_spill_costs(env, arg_info);
+		spill_node(env, arg_info);
+
+		set_irn_n(spill->spill, i, arg_info->spills->spill);
+	}
+	DBG((dbg, LEVEL_1, "... done spilling Phi %+F, created PhiM %+F\n", phi,
+	     spill->spill));
+}
+
+/**
+ * Spill a node.
+ *
+ * @param senv      the spill environment
+ * @param to_spill  the node that should be spilled
+ */
+static void spill_node(spill_env_t *env, spill_info_t *spillinfo)
+{
+	ir_node *to_spill;
+
+	/* node is already spilled */
+	if(spillinfo->spills != NULL && spillinfo->spills->spill != NULL)
+		return;
+
+	to_spill = spillinfo->to_spill;
+
+	if (is_Phi(to_spill) && ir_nodeset_contains(&env->mem_phis, to_spill)) {
+		spill_phi(env, spillinfo);
+	} else {
+		spill_irn(env, spillinfo);
+	}
+}
+
+/*
+ *
+ *  ____                      _            _       _ _
+ * |  _ \ ___ _ __ ___   __ _| |_ ___ _ __(_) __ _| (_)_______
+ * | |_) / _ \ '_ ` _ \ / _` | __/ _ \ '__| |/ _` | | |_  / _ \
+ * |  _ <  __/ | | | | | (_| | ||  __/ |  | | (_| | | |/ /  __/
+ * |_| \_\___|_| |_| |_|\__,_|\__\___|_|  |_|\__,_|_|_/___\___|
+ *
+ */
+
+/**
+ * Tests whether value @p arg is available before node @p reloader
+ * @returns 1 if value is available, 0 otherwise
+ */
+static int is_value_available(spill_env_t *env, const ir_node *arg,
+                              const ir_node *reloader)
+{
+	if(is_Unknown(arg) || arg == new_NoMem())
+		return 1;
+
+	if(be_is_Spill(arg))
+		return 1;
+
+	if(arg == get_irg_frame(env->irg))
+		return 1;
+
+	/* hack for now (happens when command should be inserted at end of block) */
+	if(is_Block(reloader)) {
+		return 0;
+	}
+
+	/*
+	 * Ignore registers are always available
+	 */
+	if (arch_irn_is(arg, ignore)) {
+		return 1;
+	}
+
+ 	/* the following test does not work while spilling,
+	 * because the liveness info is not adapted yet to the effects of the
+	 * additional spills/reloads.
+	 */
+#if 0
+	/* we want to remat before the insn reloader
+	 * thus an arguments is alive if
+	 *   - it interferes with the reloaders result
+	 *   - or it is (last-) used by reloader itself
+	 */
+	if (values_interfere(env->birg->lv, reloader, arg)) {
+		return 1;
+	}
+
+	arity = get_irn_arity(reloader);
+	for (i = 0; i < arity; ++i) {
+		ir_node *rel_arg = get_irn_n(reloader, i);
+		if (rel_arg == arg)
+			return 1;
+	}
+#endif
+
+ 	return 0;
+}
+
+/**
+ * Checks whether the node can principally be rematerialized
+ */
+static int is_remat_node(const ir_node *node)
+{
+	assert(!be_is_Spill(node));
+
+	if (arch_irn_is(node, rematerializable))
+		return 1;
+
+	return 0;
+}
+
+/**
+ * Check if a node is rematerializable. This tests for the following conditions:
+ *
+ * - The node itself is rematerializable
+ * - All arguments of the node are available or also rematerialisable
+ * - The costs for the rematerialisation operation is less or equal a limit
+ *
+ * Returns the costs needed for rematerialisation or something
+ * >= REMAT_COST_INFINITE if remat is not possible.
+ */
+static int check_remat_conditions_costs(spill_env_t *env,
+		const ir_node *spilled, const ir_node *reloader, int parentcosts)
+{
+	int i, arity;
+	int argremats;
+	int costs = 0;
+
+	if (!is_remat_node(spilled))
+		return REMAT_COST_INFINITE;
+
+	if(be_is_Reload(spilled)) {
+		costs += 2;
+	} else {
+		costs += arch_get_op_estimated_cost(spilled);
+	}
+	if(parentcosts + costs >= env->reload_cost + env->spill_cost) {
+		return REMAT_COST_INFINITE;
+	}
+	if (arch_irn_is(spilled, modify_flags)) {
+		return REMAT_COST_INFINITE;
+	}
+
+	argremats = 0;
+	for(i = 0, arity = get_irn_arity(spilled); i < arity; ++i) {
+		ir_node *arg = get_irn_n(spilled, i);
+
+		if(is_value_available(env, arg, reloader))
+			continue;
+
+		/* we have to rematerialize the argument as well */
+		if(argremats >= 1) {
+			/* we only support rematerializing 1 argument at the moment,
+			 * so that we don't have to care about register pressure
+			 */
+			return REMAT_COST_INFINITE;
 		}
+		argremats++;
+
+		costs += check_remat_conditions_costs(env, arg, reloader,
+		                                      parentcosts + costs);
+		if(parentcosts + costs >= env->reload_cost + env->spill_cost)
+			return REMAT_COST_INFINITE;
 	}
-	return ctx->spill;
+
+	return costs;
 }
 
-ir_node *be_spill_node(spill_env_t *senv, ir_node *to_spill, pset *mem_phis) {
+/**
+ * Re-materialize a node.
+ *
+ * @param senv      the spill environment
+ * @param spilled   the node that was spilled
+ * @param reloader  a irn that requires a reload
+ */
+static ir_node *do_remat(spill_env_t *env, ir_node *spilled, ir_node *reloader)
+{
+	int i, arity;
 	ir_node *res;
-	if (pset_find_ptr(mem_phis, to_spill))
-		res = be_spill_phi(senv, to_spill, to_spill, mem_phis);
-	else
-		res = be_spill_irn(senv, to_spill, to_spill);
+	ir_node *bl;
+	ir_node **ins;
+
+	if(is_Block(reloader)) {
+		bl = reloader;
+	} else {
+		bl = get_nodes_block(reloader);
+	}
+
+	ins = alloca(get_irn_arity(spilled) * sizeof(ins[0]));
+	for(i = 0, arity = get_irn_arity(spilled); i < arity; ++i) {
+		ir_node *arg = get_irn_n(spilled, i);
+
+		if(is_value_available(env, arg, reloader)) {
+			ins[i] = arg;
+		} else {
+			ins[i] = do_remat(env, arg, reloader);
+#ifdef FIRM_STATISTICS
+			/* don't count the recursive call as remat */
+			env->remat_count--;
+#endif
+		}
+	}
+
+	/* create a copy of the node */
+	res = new_ir_node(get_irn_dbg_info(spilled), env->irg, bl,
+	                  get_irn_op(spilled), get_irn_mode(spilled),
+	                  get_irn_arity(spilled), ins);
+	copy_node_attr(spilled, res);
+	arch_env_mark_remat(env->arch_env, res);
+	new_backedge_info(res);
+
+	DBG((dbg, LEVEL_1, "Insert remat %+F of %+F before reloader %+F\n", res, spilled, reloader));
+
+	if (! is_Proj(res)) {
+		/* insert in schedule */
+		sched_reset(res);
+		sched_add_before(reloader, res);
+#ifdef FIRM_STATISTICS
+		env->remat_count++;
+#endif
+	}
 
 	return res;
 }
 
-void be_insert_spills_reloads(spill_env_t *senv, pset *mem_phis, pset *reload_set)
+double be_get_spill_costs(spill_env_t *env, ir_node *to_spill, ir_node *before)
 {
-	ir_graph *irg = senv->session->irg;
-	ir_node *irn;
-	spill_info_t *si;
-	struct obstack ob;
+	ir_node *block = get_nodes_block(before);
+	double   freq  = get_block_execfreq(env->exec_freq, block);
+	(void) to_spill;
 
-	obstack_init(&ob);
+	return env->spill_cost * freq;
+}
 
-	/* process each spilled node */
-	for(si = set_first(senv->spills); si; si = set_next(senv->spills)) {
-		reloader_t *rld;
-		ir_node **reloads;
-		int n_reloads = 0;
-		ir_mode *mode = get_irn_mode(si->spilled_node);
+unsigned be_get_reload_costs_no_weight(spill_env_t *env, const ir_node *to_spill,
+                                       const ir_node *before)
+{
+	if(be_do_remats) {
+		/* is the node rematerializable? */
+		unsigned costs = check_remat_conditions_costs(env, to_spill, before, 0);
+		if(costs < (unsigned) env->reload_cost)
+			return costs;
+	}
 
-		/* go through all reloads for this spill */
-		for(rld = si->reloaders; rld; rld = rld->next) {
-			/* the spill for this reloader */
-			ir_node *spill   = be_spill_node(senv, si->spilled_node, mem_phis);
-
-			/* the reload */
-			ir_node *bl      = is_Block(rld->reloader) ? rld->reloader : get_nodes_block(rld->reloader);
-			ir_node *reload  = new_Reload(senv->session->main_env->node_factory,
-														senv->cls, irg, bl, mode, spill);
-
-			DBG((senv->dbg, LEVEL_2, " RELOADER %+F   Reload %+F of %+F\n",
-						rld->reloader, reload, si->spilled_node));
-			if(reload_set)
-				pset_insert_ptr(reload_set, reload);
-
-			/* remember the reaload */
-			obstack_ptr_grow(&ob, reload);
-			sched_add_before(rld->reloader, reload);
-			n_reloads++;
+	return env->reload_cost;
+}
+
+double be_get_reload_costs(spill_env_t *env, ir_node *to_spill, ir_node *before)
+{
+	ir_node      *block = get_nodes_block(before);
+	double        freq  = get_block_execfreq(env->exec_freq, block);
+
+	if(be_do_remats) {
+		/* is the node rematerializable? */
+		int costs = check_remat_conditions_costs(env, to_spill, before, 0);
+		if(costs < env->reload_cost)
+			return costs * freq;
+	}
+
+	return env->reload_cost * freq;
+}
+
+int be_is_rematerializable(spill_env_t *env, const ir_node *to_remat,
+                           const ir_node *before)
+{
+	return check_remat_conditions_costs(env, to_remat, before, 0) < REMAT_COST_INFINITE;
+}
+
+double be_get_reload_costs_on_edge(spill_env_t *env, ir_node *to_spill,
+                                   ir_node *block, int pos)
+{
+	ir_node *before = get_block_insertion_point(block, pos);
+	return be_get_reload_costs(env, to_spill, before);
+}
+
+/*
+ *  ___                     _     ____      _                 _
+ * |_ _|_ __  ___  ___ _ __| |_  |  _ \ ___| | ___   __ _  __| |___
+ *  | || '_ \/ __|/ _ \ '__| __| | |_) / _ \ |/ _ \ / _` |/ _` / __|
+ *  | || | | \__ \  __/ |  | |_  |  _ <  __/ | (_) | (_| | (_| \__ \
+ * |___|_| |_|___/\___|_|   \__| |_| \_\___|_|\___/ \__,_|\__,_|___/
+ *
+ */
+
+/**
+ * analyzes how to best spill a node and determine costs for that
+ */
+static void determine_spill_costs(spill_env_t *env, spill_info_t *spillinfo)
+{
+	ir_node *to_spill = spillinfo->to_spill;
+	ir_node *spill_block;
+	spill_t *spill;
+	double   spill_execfreq;
+
+	/* already calculated? */
+	if(spillinfo->spill_costs >= 0)
+		return;
+
+	assert(!arch_irn_is(to_spill, dont_spill));
+	assert(!be_is_Reload(to_spill));
+
+	/* some backends have virtual noreg/unknown nodes that are not scheduled
+	 * and simply always available.
+	 * TODO: this is kinda hairy, the NoMem is correct for an Unknown as Phi
+	 * predecessor (of a PhiM) but this test might match other things too...
+	 */
+	if(!sched_is_scheduled(to_spill)) {
+		/* override spillinfos or create a new one */
+		spill_t *spill = obstack_alloc(&env->obst, sizeof(spill[0]));
+		spill->after = NULL;
+		spill->next  = NULL;
+		spill->spill = new_NoMem();
+
+		spillinfo->spills      = spill;
+		spillinfo->spill_costs = 0;
+
+		DB((dbg, LEVEL_1, "don't spill %+F use NoMem\n", to_spill));
+		return;
+	}
+
+	spill_block    = get_nodes_block(to_spill);
+	spill_execfreq = get_block_execfreq(env->exec_freq, spill_block);
+
+	if (is_Phi(to_spill) && ir_nodeset_contains(&env->mem_phis, to_spill)) {
+		/* TODO calculate correct costs...
+		 * (though we can't remat this node anyway so no big problem) */
+		spillinfo->spill_costs = env->spill_cost * spill_execfreq;
+		return;
+	}
+
+	if(spillinfo->spills != NULL) {
+		spill_t *s;
+		double   spills_execfreq;
+
+		/* calculate sum of execution frequencies of individual spills */
+		spills_execfreq = 0;
+		s               = spillinfo->spills;
+		for( ; s != NULL; s = s->next) {
+			ir_node *spill_block = get_block(s->after);
+			double   freq = get_block_execfreq(env->exec_freq, spill_block);
+
+			spills_execfreq += freq;
+		}
+
+		DB((dbg, LEVEL_1, "%+F: latespillcosts %f after def: %f\n", to_spill,
+		    spills_execfreq * env->spill_cost,
+		    spill_execfreq * env->spill_cost));
+
+		/* multi-/latespill is advantageous -> return*/
+		if(spills_execfreq < spill_execfreq) {
+			DB((dbg, LEVEL_1, "use latespills for %+F\n", to_spill));
+			spillinfo->spill_costs = spills_execfreq * env->spill_cost;
+			return;
 		}
+	}
+
+	/* override spillinfos or create a new one */
+	spill        = obstack_alloc(&env->obst, sizeof(spill[0]));
+	spill->after = skip_keeps_phis(to_spill);
+	spill->next  = NULL;
+	spill->spill = NULL;
+
+	spillinfo->spills      = spill;
+	spillinfo->spill_costs = spill_execfreq * env->spill_cost;
+	DB((dbg, LEVEL_1, "spill %+F after definition\n", to_spill));
+}
+
+void make_spill_locations_dominate_irn(spill_env_t *env, ir_node *irn)
+{
+	const spill_info_t *si = get_spillinfo(env, irn);
+	ir_node *start_block   = get_irg_start_block(get_irn_irg(irn));
+	int n_blocks           = get_Block_dom_max_subtree_pre_num(start_block);
+	bitset_t *reloads      = bitset_alloca(n_blocks);
+	reloader_t *r;
+	spill_t *s;
+
+	if (si == NULL)
+		return;
 
-		assert(n_reloads > 0);
-		reloads = obstack_finish(&ob);
-		be_introduce_copies_ignore(senv->session->dom_front, si->spilled_node,
-				n_reloads, reloads, mem_phis);
-		obstack_free(&ob, reloads);
+	/* Fill the bitset with the dominance pre-order numbers
+	 * of the blocks the reloads are located in. */
+	for (r = si->reloaders; r != NULL; r = r->next) {
+		ir_node *bl = get_nodes_block(r->reloader);
+		bitset_set(reloads, get_Block_dom_tree_pre_num(bl));
 	}
 
-	obstack_free(&ob, NULL);
+	/* Now, cancel out all the blocks that are dominated by each spill.
+	 * If the bitset is not empty after that, we have reloads that are
+	 * not dominated by any spill. */
+	for (s = si->spills; s != NULL; s = s->next) {
+		ir_node *bl = get_nodes_block(s->after);
+		int start   = get_Block_dom_tree_pre_num(bl);
+		int end     = get_Block_dom_max_subtree_pre_num(bl);
 
-	for(irn = pset_first(mem_phis); irn; irn = pset_next(mem_phis)) {
-		int i, n;
-		for(i = 0, n = get_irn_arity(irn); i < n; ++i)
-			set_irn_n(irn, i, new_r_Bad(senv->session->irg));
-		sched_remove(irn);
+		bitset_clear_range(reloads, start, end);
 	}
+
+	if (!bitset_is_empty(reloads))
+		be_add_spill(env, si->to_spill, si->to_spill);
 }
 
-void be_add_spill(spill_env_t *senv, ir_node *to_spill, ir_node *before)
+void be_insert_spills_reloads(spill_env_t *env)
 {
-	spill_info_t templ, *res;
-	reloader_t *rel;
+	const ir_exec_freq    *exec_freq = env->exec_freq;
+	spill_info_t          *si;
+	ir_nodeset_iterator_t  iter;
+	ir_node               *node;
+
+	BE_TIMER_PUSH(t_ra_spill_apply);
+
+	/* create all phi-ms first, this is needed so, that phis, hanging on
+	   spilled phis work correctly */
+	foreach_ir_nodeset(&env->mem_phis, node, iter) {
+		spill_info_t *info = get_spillinfo(env, node);
+		spill_node(env, info);
+	}
+
+	/* process each spilled node */
+	for (si = set_first(env->spills); si; si = set_next(env->spills)) {
+		reloader_t *rld;
+		ir_node  *to_spill        = si->to_spill;
+		ir_mode  *mode            = get_irn_mode(to_spill);
+		ir_node **copies          = NEW_ARR_F(ir_node*, 0);
+		double    all_remat_costs = 0; /** costs when we would remat all nodes */
+		int       force_remat     = 0;
+
+		DBG((dbg, LEVEL_1, "\nhandling all reloaders of %+F:\n", to_spill));
+
+		determine_spill_costs(env, si);
+
+		/* determine possibility of rematerialisations */
+		if(be_do_remats) {
+			/* calculate cost savings for each indivial value when it would
+			   be rematted instead of reloaded */
+			for (rld = si->reloaders; rld != NULL; rld = rld->next) {
+				double   freq;
+				int      remat_cost;
+				int      remat_cost_delta;
+				ir_node *block;
+				ir_node *reloader = rld->reloader;
+
+				if(rld->rematted_node != NULL) {
+					DBG((dbg, LEVEL_2, "\tforced remat %+F before %+F\n",
+					     rld->rematted_node, reloader));
+					continue;
+				}
+				if(rld->remat_cost_delta >= REMAT_COST_INFINITE) {
+					DBG((dbg, LEVEL_2, "\treload before %+F is forbidden\n",
+					     reloader));
+					all_remat_costs = REMAT_COST_INFINITE;
+					continue;
+				}
+
+				remat_cost  = check_remat_conditions_costs(env, to_spill,
+				                                           reloader, 0);
+				if(remat_cost >= REMAT_COST_INFINITE) {
+					DBG((dbg, LEVEL_2, "\tremat before %+F not possible\n",
+					     reloader));
+					rld->remat_cost_delta = REMAT_COST_INFINITE;
+					all_remat_costs       = REMAT_COST_INFINITE;
+					continue;
+				}
+
+				remat_cost_delta      = remat_cost - env->reload_cost;
+				rld->remat_cost_delta = remat_cost_delta;
+				block                 = is_Block(reloader) ? reloader : get_nodes_block(reloader);
+				freq                  = get_block_execfreq(exec_freq, block);
+				all_remat_costs      += remat_cost_delta * freq;
+				DBG((dbg, LEVEL_2, "\tremat costs delta before %+F: "
+				     "%d (rel %f)\n", reloader, remat_cost_delta,
+				     remat_cost_delta * freq));
+			}
+			if(all_remat_costs < REMAT_COST_INFINITE) {
+				/* we don't need the costs for the spill if we can remat
+				   all reloaders */
+				all_remat_costs -= si->spill_costs;
+
+				DBG((dbg, LEVEL_2, "\tspill costs %d (rel %f)\n",
+				     env->spill_cost, si->spill_costs));
+			}
+
+			if(all_remat_costs < 0) {
+				DBG((dbg, LEVEL_1, "\nforcing remats of all reloaders (%f)\n",
+				     all_remat_costs));
+				force_remat = 1;
+			}
+		}
+
+		/* go through all reloads for this spill */
+		for (rld = si->reloaders; rld != NULL; rld = rld->next) {
+			ir_node *copy; /* a reload is a "copy" of the original value */
+
+			if (rld->rematted_node != NULL) {
+				copy = rld->rematted_node;
+				sched_add_before(rld->reloader, copy);
+			} else if (be_do_remats &&
+					(force_remat || rld->remat_cost_delta < 0)) {
+				copy = do_remat(env, to_spill, rld->reloader);
+			} else {
+				/* make sure we have a spill */
+				spill_node(env, si);
 
-	templ.spilled_node = to_spill;
-	templ.reloaders    = NULL;
-	res = set_insert(senv->spills, &templ, sizeof(templ), HASH_PTR(to_spill));
+				/* create a reload, use the first spill for now SSA
+				 * reconstruction for memory comes below */
+				assert(si->spills != NULL);
+				copy = be_reload(si->reload_cls, rld->reloader, mode,
+				                 si->spills->spill);
+#ifdef FIRM_STATISTICS
+				env->reload_count++;
+#endif
+			}
 
-	rel           = obstack_alloc(&senv->obst, sizeof(rel[0]));
-	rel->reloader = before;
-	rel->next     = res->reloaders;
-	res->reloaders = rel;
+			DBG((dbg, LEVEL_1, " %+F of %+F before %+F\n",
+			     copy, to_spill, rld->reloader));
+			ARR_APP1(ir_node*, copies, copy);
+		}
+
+		/* if we had any reloads or remats, then we need to reconstruct the
+		 * SSA form for the spilled value */
+		if (ARR_LEN(copies) > 0) {
+			be_ssa_construction_env_t senv;
+			/* be_lv_t *lv = be_get_birg_liveness(env->birg); */
+
+			be_ssa_construction_init(&senv, env->birg);
+			be_ssa_construction_add_copy(&senv, to_spill);
+			be_ssa_construction_add_copies(&senv, copies, ARR_LEN(copies));
+			be_ssa_construction_fix_users(&senv, to_spill);
+
+#if 0
+			/* no need to enable this as long as we invalidate liveness
+			   after this function... */
+			be_ssa_construction_update_liveness_phis(&senv);
+			be_liveness_update(to_spill);
+			len = ARR_LEN(copies);
+			for(i = 0; i < len; ++i) {
+				be_liveness_update(lv, copies[i]);
+			}
+#endif
+			be_ssa_construction_destroy(&senv);
+		}
+		/* need to reconstruct SSA form if we had multiple spills */
+		if (si->spills != NULL && si->spills->next != NULL) {
+			spill_t *spill;
+			int      spill_count = 0;
+
+			be_ssa_construction_env_t senv;
+
+			be_ssa_construction_init(&senv, env->birg);
+			spill = si->spills;
+			for( ; spill != NULL; spill = spill->next) {
+				/* maybe we rematerialized the value and need no spill */
+				if(spill->spill == NULL)
+					continue;
+				be_ssa_construction_add_copy(&senv, spill->spill);
+				spill_count++;
+			}
+			if(spill_count > 1) {
+				/* all reloads are attached to the first spill, fix them now */
+				be_ssa_construction_fix_users(&senv, si->spills->spill);
+			}
+
+			be_ssa_construction_destroy(&senv);
+		}
+
+		DEL_ARR_F(copies);
+		si->reloaders = NULL;
+	}
+
+	stat_ev_dbl("spill_spills", env->spill_count);
+	stat_ev_dbl("spill_reloads", env->reload_count);
+	stat_ev_dbl("spill_remats", env->remat_count);
+	stat_ev_dbl("spill_spilled_phis", env->spilled_phi_count);
+
+	/* Matze: In theory be_ssa_construction should take care of the liveness...
+	 * try to disable this again in the future */
+	be_liveness_invalidate(env->birg->lv);
+
+	be_remove_dead_nodes_from_schedule(env->birg);
+
+	BE_TIMER_POP(t_ra_spill_apply);
 }
 
-void be_add_spill_on_edge(spill_env_t *senv, ir_node *to_spill, ir_node *bl, int pos)
+void be_init_spill(void)
 {
-	ir_node *insert_bl = get_irn_arity(bl) == 1
-		? sched_first(bl) : get_Block_cfgpred_block(bl, pos);
-	be_add_spill(senv, to_spill, insert_bl);
+	FIRM_DBG_REGISTER(dbg, "firm.be.spill");
 }
+
+BE_REGISTER_MODULE_CONSTRUCTOR(be_init_spill);