X-Git-Url: http://nsz.repo.hu/git/?a=blobdiff_plain;f=ir%2Fbe%2Fbespill.c;h=43ed0d08136cb67d70dcc50f949731b6d0cb168e;hb=857cb493902e7d54651141fd600f980c383d5fe6;hp=dc684d011878e49ee7abbb567ccbcf59774eec4f;hpb=416f5cea230b1061936ff71810aeef66044e50f7;p=libfirm

diff --git a/ir/be/bespill.c b/ir/be/bespill.c
index dc684d011..43ed0d081 100644
--- a/ir/be/bespill.c
+++ b/ir/be/bespill.c
@@ -8,17 +8,29 @@
 #include "config.h"
 #endif
 
+#include <stdlib.h>
+
 #include "pset.h"
 #include "irnode_t.h"
 #include "ircons_t.h"
 #include "iredges_t.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 "besched.h"
+#include "belive_t.h"
+#include "besched_t.h"
 #include "bespill.h"
 #include "benode_t.h"
 #include "bechordal_t.h"
 
+/* This enables re-computation of values. Current state: Unfinished and buggy. */
+#undef BUGGY_REMAT
+
 typedef struct _reloader_t reloader_t;
 typedef struct _spill_info_t spill_info_t;
 
@@ -39,52 +51,88 @@ typedef struct _spill_ctx_t {
 } spill_ctx_t;
 
 struct _spill_env_t {
-	firm_dbg_module_t *dbg;
 	const arch_register_class_t *cls;
 	const be_chordal_env_t *chordal_env;
 	struct obstack obst;
 	set *spill_ctxs;
 	set *spills;				/**< all spill_info_t's, which must be placed */
-	pset *mem_phis;				/**< set of all special spilled phis. allocated and freed seperately */
-	decide_irn_t is_mem_phi;	/**< callback func to decide if a phi needs special spilling */
-	void *data;					/**< data passed to all callbacks */
+	pset *mem_phis;				/**< set of all special spilled phis. allocated and freed separately */
+	ir_node **copies;			/**< set of copies placed because of phi spills */
+	DEBUG_ONLY(firm_dbg_module_t *dbg;)
 };
 
+/* associated Phi -> Spill*/
+typedef struct _phi_spill_assoc_t {
+	ir_node *phi;
+	ir_node *spill;
+} phi_spill_assoc_t;
+
+/**
+ * Compare two Phi->Spill associations.
+ */
+static int cmp_phi_spill_assoc(const void *a, const void *b, size_t n) {
+	const phi_spill_assoc_t *p1 = a;
+	const phi_spill_assoc_t *p2 = b;
+	return p1->phi != p2->phi;
+}
+
+/**
+ * compare two spill contexts.
+ */
 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);
+	return p->user != q->user || p->spilled != q->spilled;
 }
 
+/**
+ * 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);
+	return xx->spilled_node != yy->spilled_node;
 }
 
-spill_env_t *be_new_spill_env(firm_dbg_module_t *dbg,
-							  const be_chordal_env_t *chordal_env,
-							  decide_irn_t is_mem_phi, void *data) {
-
-	spill_env_t *env = malloc(sizeof(env[0]));
-	env->spill_ctxs  = new_set(cmp_spillctx, 1024);
-	env->spills      = new_set(cmp_spillinfo, 1024);
-	env->cls         = chordal_env->cls;
-	env->dbg         = dbg;
-	env->is_mem_phi  = is_mem_phi;
-	env->data        = data;
-	env->chordal_env = chordal_env;
+DEBUG_ONLY(
+/* Sets the debug module of a spill environment. */
+void be_set_spill_env_dbg_module(spill_env_t *env, firm_dbg_module_t *dbg) {
+	env->dbg = dbg;
+}
+)
+
+/* Creates a new spill environment. */
+spill_env_t *be_new_spill_env(const be_chordal_env_t *chordal_env) {
+	spill_env_t *env	= xmalloc(sizeof(env[0]));
+	env->spill_ctxs		= new_set(cmp_spillctx, 1024);
+	env->spills			= new_set(cmp_spillinfo, 1024);
+	env->cls			= chordal_env->cls;
+	env->chordal_env	= chordal_env;
+	env->mem_phis		= pset_new_ptr_default();
+	env->copies			= NEW_ARR_F(ir_node*, 0);
 	obstack_init(&env->obst);
 	return env;
 }
 
-void be_delete_spill_env(spill_env_t *senv) {
-	del_set(senv->spill_ctxs);
-	del_set(senv->spills);
-	obstack_free(&senv->obst, NULL);
-	free(senv);
+/* Deletes a spill environment. */
+void be_delete_spill_env(spill_env_t *env) {
+	del_set(env->spill_ctxs);
+	del_set(env->spills);
+	del_pset(env->mem_phis);
+	DEL_ARR_F(env->copies);
+	obstack_free(&env->obst, NULL);
+	free(env);
 }
 
+/**
+ * Returns a spill context. If the context did not exists, create one.
+ *
+ * @param sc        the set containing all spill contexts
+ * @param to_spill  the node that should be spilled
+ * @param ctx_irn   an user of the spilled node
+ *
+ * @return a spill context.
+ */
 static spill_ctx_t *be_get_spill_ctx(set *sc, ir_node *to_spill, ir_node *ctx_irn) {
 	spill_ctx_t templ;
 
@@ -95,174 +143,773 @@ static spill_ctx_t *be_get_spill_ctx(set *sc, ir_node *to_spill, ir_node *ctx_ir
 	return set_insert(sc, &templ, sizeof(templ), HASH_COMBINE(HASH_PTR(to_spill), HASH_PTR(ctx_irn)));
 }
 
+/**
+ * Schedules a node after an instruction. (That is the place after all projs and phis
+ * that are scheduled after the instruction)
+ */
+static void sched_add_after_insn(ir_node *sched_after, ir_node *node) {
+	ir_node *next = sched_next(sched_after);
+	while(!sched_is_end(next)) {
+		if(!is_Proj(next) && !is_Phi(next))
+			break;
+		next = sched_next(next);
+	}
+
+	if(sched_is_end(next)) {
+		next = sched_last(get_nodes_block(sched_after));
+		sched_add_after(next, node);
+	} else {
+		sched_add_before(next, node);
+	}
+}
+
+/**
+ * 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 ir_node *be_spill_irn(spill_env_t *senv, ir_node *irn, ir_node *ctx_irn) {
 	spill_ctx_t *ctx;
+	const be_main_env_t *env = senv->chordal_env->birg->main_env;
 	DBG((senv->dbg, LEVEL_1, "%+F in ctx %+F\n", irn, ctx_irn));
 
+	// Has the value already been spilled?
 	ctx = be_get_spill_ctx(senv->spill_ctxs, irn, ctx_irn);
-	if(!ctx->spill) {
-		const be_main_env_t *env = senv->chordal_env->main_env;
-		ctx->spill = be_spill(env->node_factory, env->arch_env, irn, ctx_irn);
+	if(ctx->spill)
+		return ctx->spill;
+
+	/* Trying to spill an already spilled value, no need for a new spill
+	 * node then, we can simply connect to the same one for this reload
+	 */
+	if(be_is_Reload(irn)) {
+		return get_irn_n(irn, be_pos_Reload_mem);
 	}
 
+	ctx->spill = be_spill(env->arch_env, irn, ctx_irn);
+	sched_add_after_insn(irn, ctx->spill);
+
 	return ctx->spill;
 }
 
 /**
- * If the first usage of a phi result would be out of memory
+ * Removes all copies introduced for phi-spills
+ */
+static void remove_copies(spill_env_t *env) {
+	int i;
+
+	for(i = 0; i < ARR_LEN(env->copies); ++i) {
+		ir_node *node = env->copies[i];
+		ir_node *src;
+		const ir_edge_t *edge, *ne;
+
+		assert(be_is_Copy(node));
+
+		src = be_get_Copy_op(node);
+		foreach_out_edge_safe(node, edge, ne) {
+			ir_node *user = get_edge_src_irn(edge);
+			int user_pos  = get_edge_src_pos(edge);
+
+			set_irn_n(user, user_pos, src);
+		}
+	}
+
+	ARR_SETLEN(ir_node*, env->copies, 0);
+}
+
+static INLINE ir_node *skip_projs(ir_node *node) {
+	while(is_Proj(node)) {
+		node = sched_next(node);
+		assert(!sched_is_end(node));
+	}
+
+	return node;
+}
+
+/**
+ * Searchs the schedule backwards until we reach the first use or def of a
+ * value or a phi.
+ * Returns the node after this node (so that you can do sched_add_before)
+ */
+static ir_node *find_last_use_def(spill_env_t *env, ir_node *block, ir_node *value) {
+	ir_node *node, *last;
+
+	last = NULL;
+	sched_foreach_reverse(block, node) {
+		int i, arity;
+
+		if(is_Phi(node)) {
+			return last;
+		}
+		if(value == node) {
+			return skip_projs(last);
+		}
+		for(i = 0, arity = get_irn_arity(node); i < arity; ++i) {
+			ir_node *arg = get_irn_n(node, i);
+			if(arg == value) {
+				return skip_projs(last);
+			}
+		}
+		last = node;
+	}
+
+	// simply return first node if no def or use found
+	return sched_first(block);
+}
+
+/**
+ * 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
+ *
+ * @return a be_Spill node
  */
-static ir_node *be_spill_phi(spill_env_t *senv, ir_node *phi, ir_node *ctx_irn) {
-	int i, n = get_irn_arity(phi);
-	ir_node **ins, *bl = get_nodes_block(phi);
-	ir_graph *irg = senv->chordal_env->irg;
+static ir_node *spill_phi(spill_env_t *senv, ir_node *phi, ir_node *ctx_irn, set *already_visited_phis, bitset_t *bs) {
+	int         i;
+	int arity = get_irn_arity(phi);
+	ir_graph    *irg      = senv->chordal_env->irg;
+	ir_node     *bl       = get_nodes_block(phi);
+	ir_node     **ins, *phi_spill;
+	phi_spill_assoc_t key;
 	spill_ctx_t *ctx;
 
 	assert(is_Phi(phi));
 	DBG((senv->dbg, LEVEL_1, "%+F in ctx %+F\n", phi, ctx_irn));
 
+	/* build a new PhiM */
+	NEW_ARR_A(ir_node *, ins, arity);
+	for (i = 0; i < arity; ++i) {
+		ins[i] = new_r_Bad(irg);
+	}
+	phi_spill = new_r_Phi(senv->chordal_env->irg, bl, arity, ins, mode_M);
+	key.phi   = phi;
+	key.spill = phi_spill;
+	set_insert(already_visited_phis, &key, sizeof(key), HASH_PTR(phi));
+	bitset_set(bs, get_irn_idx(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->chordal_env->irg, bl, n, ins, mode_M);
-		free(ins);
-
-		/* re-wire the phiM */
-		for(i=0; i<n; ++i) {
+	if (! ctx->spill) {
+		/* collect all arguments of the phi */
+		for (i = 0; i < arity; ++i) {
 			ir_node *arg = get_irn_n(phi, i);
 			ir_node *sub_res;
-
-			if(is_Phi(arg) && pset_find_ptr(senv->mem_phis, arg))
-				sub_res = be_spill_phi(senv, arg, ctx_irn);
-			else
+			phi_spill_assoc_t *entry;
+
+			if(is_Phi(arg) && pset_find_ptr(senv->mem_phis, arg)) {
+				// looping edge?
+				if(arg == phi) {
+					sub_res = phi_spill;
+				} else if (! bitset_is_set(bs, get_irn_idx(arg))) {
+					sub_res = spill_phi(senv, arg, ctx_irn, already_visited_phis, bs);
+				} else {
+					/* we already visited the argument phi: get it's spill */
+					key.phi   = arg;
+					key.spill = NULL;
+					entry     = set_find(already_visited_phis, &key, sizeof(key), HASH_PTR(arg));
+					assert(entry && "argument phi already visited, but no spill found?!?");
+					sub_res   = entry->spill;
+					assert(sub_res && "spill missing?!?");
+				}
+			} else {
 				sub_res = be_spill_irn(senv, arg, ctx_irn);
+			}
 
-			set_irn_n(ctx->spill, i, sub_res);
+			set_irn_n(phi_spill, i, sub_res);
 		}
+
+		ctx->spill = phi_spill;
 	}
 	return ctx->spill;
 }
 
+/**
+ * Spill a node.
+ *
+ * @param senv      the spill environment
+ * @param to_spill  the node that should be spilled
+ *
+ * @return a be_Spill node
+ */
 static ir_node *be_spill_node(spill_env_t *senv, ir_node *to_spill) {
-	ir_node *res;
-	if (pset_find_ptr(senv->mem_phis, to_spill))
-		res = be_spill_phi(senv, to_spill, to_spill);
-	else
+	ir_graph *irg = get_irn_irg(to_spill);
+	ir_node  *res;
+
+	if (pset_find_ptr(senv->mem_phis, to_spill)) {
+		set *already_visited_phis = new_set(cmp_phi_spill_assoc, 10);
+		bitset_t *bs = bitset_alloca(get_irg_last_idx(irg));
+		res = spill_phi(senv, to_spill, to_spill, already_visited_phis, bs);
+		del_set(already_visited_phis);
+	} else {
 		res = be_spill_irn(senv, to_spill, to_spill);
+	}
 
 	return res;
 }
 
-static void phi_walker(ir_node *irn, void *env) {
-	spill_env_t *senv = env;
-	const arch_env_t *arch = senv->chordal_env->main_env->arch_env;
+#ifdef BUGGY_REMAT
+
+/**
+ * Check if a spilled node could be rematerialized.
+ *
+ * @param senv      the spill environment
+ * @param spill     the Spill node
+ * @param spilled   the node that was spilled
+ * @param reloader  a irn that requires a reload
+ */
+static int check_remat_conditions(spill_env_t *senv, ir_node *spilled, ir_node *reloader) {
+	int pos, max;
+
+	/* check for 'normal' spill and general remat condition */
+	if (!arch_irn_is(senv->chordal_env->birg->main_env->arch_env, spilled, rematerializable))
+		return 0;
+
+	/* check availability of original arguments */
+	if (is_Block(reloader)) {
+
+		/* we want to remat at the end of a block.
+		 * thus all arguments must be alive at the end of the block
+		 */
+		for (pos=0, max=get_irn_arity(spilled); pos<max; ++pos) {
+			ir_node *arg = get_irn_n(spilled, pos);
+			if (!is_live_end(reloader, arg))
+				return 0;
+		}
+
+	} else {
+
+		/* we want to remat before the insn reloader
+		 * thus an arguments is alive if
+		 *   - it interferes with the reloaders result
+		 * or
+		 *   - or it is (last-) used by reloader itself
+		 */
+		for (pos=0, max=get_irn_arity(spilled); pos<max; ++pos) {
+			ir_node *arg = get_irn_n(spilled, pos);
+			int i, m;
+
+			if (values_interfere(reloader, arg))
+				goto is_alive;
+
+			for (i=0, m=get_irn_arity(reloader); i<m; ++i) {
+				ir_node *rel_arg = get_irn_n(reloader, i);
+				if (rel_arg == arg)
+					goto is_alive;
+			}
+
+			/* arg is not alive before reloader */
+			return 0;
+
+is_alive:	;
+
+		}
 
-	if (is_Phi(irn) && arch_irn_has_reg_class(arch, irn, 0, senv->cls)
-			&& senv->is_mem_phi(irn, senv->data)) {
-		DBG((senv->dbg, LEVEL_1, "  %+F\n", irn));
-		pset_insert_ptr(senv->mem_phis, irn);
 	}
+
+	return 1;
 }
 
-void be_insert_spills_reloads(spill_env_t *senv, pset *reload_set) {
-	ir_graph *irg = senv->chordal_env->irg;
-	ir_node *irn;
-	spill_info_t *si;
-	struct obstack ob;
+#else /* BUGGY_REMAT */
+
+/**
+ * A very simple rematerialization checker.
+ *
+ * @param senv      the spill environment
+ * @param spill     the Spill node
+ * @param spilled   the node that was spilled
+ * @param reloader  a irn that requires a reload
+ */
+static int check_remat_conditions(spill_env_t *senv, ir_node *spilled, ir_node *reloader) {
+	const arch_env_t *aenv = senv->chordal_env->birg->main_env->arch_env;
 
-	obstack_init(&ob);
+	return get_irn_arity(spilled) == 0 &&
+		   arch_irn_is(aenv, spilled, rematerializable);
+}
+
+#endif /* BUGGY_REMAT */
+
+/**
+ * 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 *senv, ir_node *spilled, ir_node *reloader) {
+	ir_node *res;
+	ir_node *bl = (is_Block(reloader)) ? reloader : get_nodes_block(reloader);
+
+	/* recompute the value */
+	res = new_ir_node(get_irn_dbg_info(spilled), senv->chordal_env->irg, bl,
+		get_irn_op(spilled),
+		get_irn_mode(spilled),
+		get_irn_arity(spilled),
+		get_irn_in(spilled) + 1);
+	copy_node_attr(spilled, res);
+
+	DBG((senv->dbg, LEVEL_1, "Insert remat %+F before reloader %+F\n", res, reloader));
+
+	/* insert in schedule */
+	if (is_Block(reloader)) {
+		ir_node *insert = sched_skip(reloader, 0, sched_skip_cf_predicator, (void *) senv->chordal_env->birg->main_env->arch_env);
+		sched_add_after(insert, res);
+	} else {
+		sched_add_before(reloader, res);
+	}
+
+	return res;
+}
 
-	/* get all special spilled phis */
-	DBG((senv->dbg, LEVEL_1, "Mem-phis:\n"));
-	senv->mem_phis = pset_new_ptr_default();
-	irg_walk_graph(senv->chordal_env->irg, phi_walker, NULL, senv);
+static place_copies_for_phi(spill_env_t *env, ir_node* node) {
+	int i, arity;
 
-	/* Add reloads for mem_phis */
-	/* BETTER: These reloads (1) should only be inserted, if they are really needed */
-	DBG((senv->dbg, LEVEL_1, "Reloads for mem-phis:\n"));
-	for(irn = pset_first(senv->mem_phis); irn; irn = pset_next(senv->mem_phis)) {
+	assert(is_Phi(node));
+
+	/* We have to place copy nodes in the predecessor blocks to temporarily
+	 * produce new values that get separate spill slots
+	 */
+	for(i = 0, arity = get_irn_arity(node); i < arity; ++i) {
+		ir_node *pred_block, *arg, *copy, *insert_point;
+
+		/* Don't do anything for looping edges (there's no need
+		 * and placing copies here breaks stuff as it suddenly
+		 * generates new living values through the whole loop)
+		 */
+		arg = get_irn_n(node, i);
+		if(arg == node)
+			continue;
+
+		pred_block = get_Block_cfgpred_block(get_nodes_block(node), i);
+		copy = be_new_Copy(env->cls, get_irn_irg(arg), pred_block, arg);
+
+		ARR_APP1(ir_node*, env->copies, copy);
+		insert_point = find_last_use_def(env, pred_block, arg);
+		sched_add_before(insert_point, copy);
+
+		set_irn_n(node, i, copy);
+	}
+}
+
+void be_place_copies(spill_env_t *env) {
+	ir_node *node;
+
+	foreach_pset(env->mem_phis, node) {
+		place_copies_for_phi(env, node);
+	}
+}
+
+void be_spill_phi(spill_env_t *env, ir_node *node) {
+	spill_ctx_t *spill_ctx;
+
+	assert(is_Phi(node));
+
+	pset_insert_ptr(env->mem_phis, node);
+
+	// remove spill context for this phi (if there was one)
+	spill_ctx = be_get_spill_ctx(env->spill_ctxs, node, node);
+	if(spill_ctx != NULL) {
+		spill_ctx->spill = NULL;
+	}
+}
+
+void be_insert_spills_reloads(spill_env_t *env) {
+	const arch_env_t *arch_env = env->chordal_env->birg->main_env->arch_env;
+	//ir_node *node;
+	spill_info_t *si;
+
+#if 0
+	// Matze: This should be pointless as beladies fix_block_borders
+	// should result in the same
+	DBG((env->dbg, LEVEL_1, "Reloads for mem-phis:\n"));
+	foreach_pset(env->mem_phis, node) {
 		const ir_edge_t *e;
-		DBG((senv->dbg, LEVEL_1, " Mem-phi %+F\n", irn));
-		foreach_out_edge(irn, e) {
+
+		assert(is_Phi(node));
+
+		/* Add reloads for mem_phis */
+		/* BETTER: These reloads (1) should only be inserted, if they are really needed */
+		DBG((env->dbg, LEVEL_1, " Mem-phi %+F\n", node));
+		foreach_out_edge(node, e) {
 			ir_node *user = e->src;
-			if (is_Phi(user) && !pset_find_ptr(senv->mem_phis, user)) {
-					ir_node *use_bl = get_nodes_block(user);
-					DBG((senv->dbg, LEVEL_1, " non-mem-phi user %+F\n", user));
-					be_add_reload_on_edge(senv, irn, use_bl, e->pos); /* (1) */
+			if (is_Phi(user) && !pset_find_ptr(env->mem_phis, user)) {
+				ir_node *use_bl = get_nodes_block(user);
+				DBG((env->dbg, LEVEL_1, " non-mem-phi user %+F\n", user));
+				be_add_reload_on_edge(env, node, use_bl, e->pos); /* (1) */
 			}
 		}
 	}
+#endif
 
 	/* process each spilled node */
-	DBG((senv->dbg, LEVEL_1, "Insert spills and reloads:\n"));
-	for(si = set_first(senv->spills); si; si = set_next(senv->spills)) {
+	DBG((env->dbg, LEVEL_1, "Insert spills and reloads:\n"));
+	for(si = set_first(env->spills); si; si = set_next(env->spills)) {
 		reloader_t *rld;
-		ir_node **reloads;
-		int n_reloads = 0;
 		ir_mode *mode = get_irn_mode(si->spilled_node);
+		pset *values = pset_new_ptr(16);
 
 		/* 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);
-
-			/* the reload */
-			ir_node *bl      = is_Block(rld->reloader) ? rld->reloader : get_nodes_block(rld->reloader);
-			ir_node *reload  = new_Reload(senv->chordal_env->main_env->node_factory,
-				senv->cls, irg, bl, mode, spill);
-
-			DBG((senv->dbg, LEVEL_1, " %+F of %+F before %+F\n", reload, si->spilled_node, rld->reloader));
-			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++;
-		}
+			ir_node *new_val;
 
-		assert(n_reloads > 0);
-		reloads = obstack_finish(&ob);
-		be_introduce_copies_ignore(senv->chordal_env->dom_front, si->spilled_node,
-				n_reloads, reloads, senv->mem_phis);
-		obstack_free(&ob, reloads);
-	}
+			if (check_remat_conditions(env, si->spilled_node, rld->reloader)) {
+				new_val = do_remat(env, si->spilled_node, rld->reloader);
+			} else {
+				/* the spill for this reloader */
+				ir_node *spill = be_spill_node(env, si->spilled_node);
 
-	obstack_free(&ob, NULL);
+				/* do a reload */
+				new_val = be_reload(arch_env, env->cls, rld->reloader, mode, spill);
+			}
+
+			DBG((env->dbg, LEVEL_1, " %+F of %+F before %+F\n", new_val, si->spilled_node, rld->reloader));
+			pset_insert_ptr(values, new_val);
+		}
 
-	for(irn = pset_first(senv->mem_phis); irn; irn = pset_next(senv->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->chordal_env->irg));
-		sched_remove(irn);
+		/* introduce copies, rewire the uses */
+		assert(pset_count(values) > 0 && "???");
+		pset_insert_ptr(values, si->spilled_node);
+		be_ssa_constr_set_ignore(env->chordal_env->dom_front, values, env->mem_phis);
+
+		del_pset(values);
 	}
 
-	del_pset(senv->mem_phis);
+	remove_copies(env);
+
+	// reloads are placed now, but we might reuse the spill environment for further spilling decisions
+	del_set(env->spills);
+	env->spills = new_set(cmp_spillinfo, 1024);
 }
 
-void be_add_reload(spill_env_t *senv, ir_node *to_spill, ir_node *before) {
+void be_add_reload(spill_env_t *env, ir_node *to_spill, ir_node *before) {
 	spill_info_t templ, *res;
 	reloader_t *rel;
 
+	assert(sched_is_scheduled(before));
+	assert(arch_irn_consider_in_reg_alloc(env->chordal_env->birg->main_env->arch_env, env->cls, to_spill));
+
 	templ.spilled_node = to_spill;
 	templ.reloaders    = NULL;
-	res = set_insert(senv->spills, &templ, sizeof(templ), HASH_PTR(to_spill));
+	res = set_insert(env->spills, &templ, sizeof(templ), HASH_PTR(to_spill));
 
-	rel           = obstack_alloc(&senv->obst, sizeof(rel[0]));
+	rel           = obstack_alloc(&env->obst, sizeof(rel[0]));
 	rel->reloader = before;
 	rel->next     = res->reloaders;
 	res->reloaders = rel;
 }
 
-void be_add_reload_on_edge(spill_env_t *senv, ir_node *to_spill, ir_node *bl, int pos) {
-	ir_node *insert_bl = get_irn_arity(bl) == 1 ? sched_first(bl) : get_Block_cfgpred_block(bl, pos);
-	be_add_reload(senv, to_spill, insert_bl);
+void be_add_reload_on_edge(spill_env_t *env, ir_node *to_spill, ir_node *block, int pos) {
+	ir_node *predblock, *last;
+
+	/* 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)));
+		be_add_reload(env, to_spill, sched_first(block));
+		return;
+	}
+
+	/* We have to reload the value in pred-block */
+	predblock = get_Block_cfgpred_block(block, pos);
+	last = sched_last(predblock);
+
+	/* we might have projs and keepanys behind the jump... */
+	while(is_Proj(last) || be_is_Keep(last)) {
+		last = sched_prev(last);
+		assert(!sched_is_end(last));
+	}
+	assert(is_cfop(last));
+
+	// add the reload before the (cond-)jump
+	be_add_reload(env, to_spill, last);
+}
+
+/****************************************
+
+	SPILL SLOT MANAGEMENT AND OPTS
+
+****************************************/
+
+typedef struct _spill_slot_t {
+	unsigned size;
+	unsigned align;
+	pset *members;
+	ir_mode *largest_mode;	/* the mode of all members with largest size */
+} spill_slot_t;
+
+typedef struct _ss_env_t {
+	struct obstack ob;
+	be_chordal_env_t *cenv;
+	pmap *slots;		/* maps spill_contexts to spill_slots */
+	pmap *types;    /* maps modes to types */
+	DEBUG_ONLY(firm_dbg_module_t *dbg;)
+} ss_env_t;
+
+
+/**
+ * Walker: compute the spill slots
+ */
+static void compute_spill_slots_walker(ir_node *spill, void *env) {
+	ss_env_t *ssenv = env;
+	ir_node *ctx;
+	pmap_entry *entry;
+	spill_slot_t *ss;
+
+	if (!be_is_Spill(spill))
+		return;
+
+	/* check, if this spill is for a context already known */
+	ctx = be_get_Spill_context(spill);
+	entry = pmap_find(ssenv->slots, ctx);
+
+	if (!entry) {
+		struct _arch_env_t *arch_env     = ssenv->cenv->birg->main_env->arch_env;
+		const arch_register_class_t *cls = arch_get_irn_reg_class(arch_env, spill, be_pos_Spill_val);
+		ir_mode *largest_mode            = arch_register_class_mode(cls);
+
+		/* this is a new spill context */
+		ss = obstack_alloc(&ssenv->ob, sizeof(*ss));
+		ss->members      = pset_new_ptr(8);
+		ss->largest_mode = largest_mode;
+		ss->size         = get_mode_size_bytes(ss->largest_mode);
+		ss->align        = arch_isa_get_reg_class_alignment(arch_env->isa, cls);
+		pmap_insert(ssenv->slots, ctx, ss);
+	} else {
+		/* values with the same spill_ctx must go into the same spill slot */
+		ss = entry->value;
+
+#ifndef NDEBUG
+		/* ugly mega assert :-) */
+		{
+			ir_node *irn;
+			struct _arch_env_t *arch_env     = ssenv->cenv->birg->main_env->arch_env;
+			const arch_register_class_t *cls = arch_get_irn_reg_class(arch_env, spill, be_pos_Spill_val);
+			int size = get_mode_size_bytes(arch_register_class_mode(cls));
+			assert((int) ss->size == size && "Different sizes for the same spill slot are not allowed.");
+			for (irn = pset_first(ss->members); irn; irn = pset_next(ss->members)) {
+				/* use values_interfere here, because it uses the dominance check,
+					 which does work for values in memory */
+				assert(!values_interfere(spill, irn) && "Spills for the same spill slot must not interfere!");
+			}
+		}
+#endif /* NDEBUG */
+	}
+
+	pset_insert_ptr(ss->members, spill);
+}
+
+/**
+ * qsort compare function, sort spill slots by size.
+ */
+static int ss_sorter(const void *v1, const void *v2) {
+	const spill_slot_t **ss1 = (const spill_slot_t **)v1;
+	const spill_slot_t **ss2 = (const spill_slot_t **)v2;
+	return ((int) (*ss2)->size) - ((int) (*ss1)->size);
+}
+
+
+/**
+ * This function should optimize the spill slots.
+ *  - Coalescing of multiple slots
+ *  - Ordering the slots
+ *
+ * Input slots are in @p ssenv->slots
+ * @p size The count of initial spill slots in @p ssenv->slots
+ *         This also is the size of the preallocated array @p ass
+ *
+ * @return An array of spill slots @p ass in specific order
+ **/
+static void optimize_slots(ss_env_t *ssenv, int size, spill_slot_t *ass[]) {
+	int i, o, used_slots;
+	pmap_entry *entr;
+
+	i=0;
+	pmap_foreach(ssenv->slots, entr)
+		ass[i++] = entr->value;
+
+	/* Sort the array to minimize fragmentation and cache footprint.
+	   Large slots come first */
+	qsort(ass, size, sizeof(ass[0]), ss_sorter);
+
+	/* For each spill slot:
+		- assign a new offset to this slot
+	    - xor find another slot to coalesce with */
+	used_slots = 0;
+	for (i=0; i<size; ++i) {
+		/* for each spill slot */
+		ir_node *n1;
+		int tgt_slot = -1;
+
+		DBG((ssenv->dbg, LEVEL_1, "Spill slot %d members:\n", i));
+		for(n1 = pset_first(ass[i]->members); n1; n1 = pset_next(ass[i]->members))
+			DBG((ssenv->dbg, LEVEL_1, "  %+F\n", n1));
+
+
+		for (o=0; o < used_slots && tgt_slot == -1; ++o) { /* for each offset-assigned spill slot */
+			/* check inter-slot-pairs for interference */
+			ir_node *n2;
+			for(n1 = pset_first(ass[i]->members); n1; n1 = pset_next(ass[i]->members))
+				for(n2 = pset_first(ass[o]->members); n2; n2 = pset_next(ass[o]->members))
+					if(values_interfere(n1, n2)) {
+						pset_break(ass[i]->members);
+						pset_break(ass[o]->members);
+						DBG((ssenv->dbg, LEVEL_1, "    Interf %+F -- %+F\n", n1, n2));
+						goto interf_detected;
+					}
+
+			/* if we are here, there is no interference between ass[i] and ass[o] */
+			tgt_slot = o;
+
+interf_detected: /*nothing*/ ;
+		}
+
+		/* now the members of ass[i] join the members of ass[tgt_slot] */
+
+		/* do we need a new slot? */
+		if (tgt_slot == -1) {
+			tgt_slot = used_slots;
+			used_slots++;
+
+			/* init slot */
+			if (tgt_slot != i) {
+				ass[tgt_slot]->size = ass[i]->size;
+				del_pset(ass[tgt_slot]->members);
+				ass[tgt_slot]->members = pset_new_ptr(8);
+			}
+		}
+
+		/* copy the members to the target pset */
+		/* NOTE: If src and tgt pset are the same, inserting while iterating is not allowed */
+		if (tgt_slot != i)
+			for(n1 = pset_first(ass[i]->members); n1; n1 = pset_next(ass[i]->members))
+					pset_insert_ptr(ass[tgt_slot]->members, n1);
+	}
+}
+
+#define ALIGN_SPILL_AREA 16
+#define pset_foreach(pset, elm)  for(elm=pset_first(pset); elm; elm=pset_next(pset))
+
+/**
+ * Returns a spill type for a mode. Keep them in a map to reduce
+ * the number of types.
+ *
+ * @param types  a map containing all created types
+ * @param ss     the spill slot
+ *
+ * Note that type types should are identical for every mode.
+ * This rule might break if two different register classes return the same
+ * mode but different alignments.
+ */
+static ir_type *get_spill_type(pmap *types, spill_slot_t *ss) {
+	pmap_entry *e = pmap_find(types, ss->largest_mode);
+	ir_type *res;
+
+	if (! e) {
+		char buf[64];
+		snprintf(buf, sizeof(buf), "spill_slot_type_%s", get_mode_name(ss->largest_mode));
+		buf[sizeof(buf) - 1] = '\0';
+		res = new_type_primitive(new_id_from_str(buf), ss->largest_mode);
+		set_type_alignment_bytes(res, ss->align);
+		pmap_insert(types, ss->largest_mode, res);
+	} else {
+		res = e->value;
+		assert(get_type_alignment_bytes(res) == (int)ss->align);
+	}
+
+	return res;
+}
+
+/**
+ * Create spill slot entities on the frame type.
+ *
+ * @param ssenv   the spill environment
+ * @param n       number of spill slots
+ * @param ss      array of spill slots
+ */
+static void assign_entities(ss_env_t *ssenv, int n_slots, spill_slot_t *ss[]) {
+	int i, offset, frame_align;
+	ir_type *frame;
+
+	/* do not align the frame if no spill slots are needed */
+	if (n_slots <= 0)
+		return;
+
+	frame = get_irg_frame_type(ssenv->cenv->irg);
+
+	/* aligning by increasing frame size */
+	offset = get_type_size_bytes(frame);
+	offset = round_up2(offset, ALIGN_SPILL_AREA);
+
+	/* create entities and assign offsets according to size and alignment*/
+	for (i = 0; i < n_slots; ++i) {
+		char buf[64];
+		ident *name;
+		entity *spill_ent;
+		ir_node *irn;
+
+		/* build entity */
+		snprintf(buf, sizeof(buf), "spill_slot_%d", i);
+		buf[sizeof(buf) - 1] = '\0';
+		name = new_id_from_str(buf);
+
+		spill_ent = new_entity(frame, name, get_spill_type(ssenv->types, ss[i]));
+
+		/* align */
+		offset = round_up2(offset, ss[i]->align);
+		/* set */
+		set_entity_offset_bytes(spill_ent, offset);
+		/* next possible offset */
+		offset += round_up2(ss[i]->size, ss[i]->align);
+
+		pset_foreach(ss[i]->members, irn)
+			be_set_Spill_entity(irn, spill_ent);
+	}
+
+
+	/* set final size of stack frame */
+	frame_align = get_type_alignment_bytes(frame);
+	set_type_size_bytes(frame, round_up2(offset, frame_align));
+}
+
+void be_compute_spill_offsets(be_chordal_env_t *cenv) {
+	ss_env_t ssenv;
+	spill_slot_t **ss;
+	int ss_size;
+	pmap_entry *pme;
+
+	obstack_init(&ssenv.ob);
+	ssenv.cenv  = cenv;
+	ssenv.slots = pmap_create();
+	ssenv.types = pmap_create();
+	FIRM_DBG_REGISTER(ssenv.dbg, "ir.be.spillslots");
+
+	/* Get initial spill slots */
+	irg_walk_graph(cenv->irg, NULL, compute_spill_slots_walker, &ssenv);
+
+	/* Build an empty array for optimized spill slots */
+	ss_size = pmap_count(ssenv.slots);
+	ss = obstack_alloc(&ssenv.ob, ss_size * sizeof(*ss));
+	optimize_slots(&ssenv, ss_size, ss);
+
+	/* Integrate slots into the stack frame entity */
+	assign_entities(&ssenv, ss_size, ss);
+
+	/* Clean up */
+	pmap_foreach(ssenv.slots, pme)
+	del_pset(((spill_slot_t *)pme->value)->members);
+	pmap_destroy(ssenv.slots);
+	pmap_destroy(ssenv.types);
+	obstack_free(&ssenv.ob, NULL);
+
+	be_copy_entities_to_reloads(cenv->irg);
 }