X-Git-Url: http://nsz.repo.hu/git/?a=blobdiff_plain;f=ir%2Fopt%2Fopt_osr.c;h=6189ea806699ef0ab701abc289e6dd6fc4b2bf02;hb=0ac0b440ce2d239c5e7e7db56b8273559d9a7741;hp=3253615ae658a8b6943c2e311f8d60db248c79d7;hpb=c28fcf22c08f71b02ccd8edb2e091c1b6c22e540;p=libfirm

diff --git a/ir/opt/opt_osr.c b/ir/opt/opt_osr.c
index 3253615ae..6189ea806 100644
--- a/ir/opt/opt_osr.c
+++ b/ir/opt/opt_osr.c
@@ -1,20 +1,6 @@
 /*
- * 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.
+ * Copyright (C) 2012 University of Karlsruhe.
  */
 
 /**
@@ -22,15 +8,12 @@
  * @brief   Operator Strength Reduction.
  * @date    12.5.2006
  * @author  Michael Beck
- * @version $Id$
- * @summary
+ * @brief
  *  Implementation of the Operator Strength Reduction algorithm
  *  by Keith D. Cooper, L. Taylor Simpson, Christopher A. Vick.
  *  Extended version.
  */
-#ifdef HAVE_CONFIG_H
 #include "config.h"
-#endif
 
 #include "adt/pdeq.h"
 #include "iroptimize.h"
@@ -48,22 +31,23 @@
 #include "set.h"
 #include "tv.h"
 #include "hashptr.h"
+#include "util.h"
 #include "irtools.h"
 #include "irloop_t.h"
 #include "array.h"
-#include "firmstat.h"
-#include "xmalloc.h"
+#include "firmstat_t.h"
 #include "error.h"
+#include "irpass_t.h"
 
 /** The debug handle. */
 DEBUG_ONLY(static firm_dbg_module_t *dbg;)
 
 /** A scc. */
 typedef struct scc {
-	ir_node  *head;		/**< the head of the list */
-	tarval   *init;     /**< the init value iff only one exists. */
-	tarval   *incr;     /**< the induction variable increment if only a single const exists. */
-	unsigned code;      /**< == iro_Add if +incr, iro_Sub if -incr, 0 if not analysed, iro_Bad else */
+	ir_node   *head; /**< the head of the list */
+	ir_tarval *init; /**< the init value iff only one exists. */
+	ir_tarval *incr; /**< the induction variable increment if only a single const exists. */
+	unsigned   code; /**< == iro_Add if +incr, iro_Sub if -incr, 0 if not analysed, iro_Bad else */
 } scc;
 
 /** A node entry */
@@ -81,14 +65,15 @@ typedef struct node_entry {
 typedef struct iv_env {
 	struct obstack obst;    /**< an obstack for allocations */
 	ir_node  **stack;       /**< the node stack */
-	int      tos;           /**< tos index */
+	size_t   tos;           /**< tos index */
 	unsigned nextDFSnum;    /**< the current DFS number */
 	unsigned POnum;         /**< current post order number */
 	set      *quad_map;     /**< a map from (op, iv, rc) to node */
 	set      *lftr_edges;   /**< the set of lftr edges */
 	unsigned replaced;      /**< number of replaced ops */
 	unsigned lftr_replaced; /**< number of applied linear function test replacements */
-	unsigned flags;         /**< additional flags */
+	unsigned osr_flags;     /**< additional flags steering the transformation */
+	unsigned need_postpass; /**< set, if a post pass is needed to fix Add and Sub nodes */
 	/** Function called to process a SCC. */
 	void (*process_scc)(scc *pscc, struct iv_env *env);
 } iv_env;
@@ -97,7 +82,7 @@ typedef struct iv_env {
  * An entry in the (op, node, node) -> node map.
  */
 typedef struct quadruple_t {
-	ir_opcode code;  /**< the opcode of the reduced operation */
+	unsigned   code; /**< the opcode of the reduced operation */
 	ir_node   *op1;  /**< the first operand the reduced operation */
 	ir_node   *op2;  /**< the second operand of the reduced operation */
 
@@ -110,7 +95,7 @@ typedef struct quadruple_t {
 typedef struct LFTR_edge {
 	ir_node   *src;   /**< the source node */
 	ir_node   *dst;   /**< the destination node */
-	ir_opcode code;   /**< the opcode that must be applied */
+	unsigned  code;   /**< the opcode that must be applied */
 	ir_node   *rc;    /**< the region const that must be applied */
 } LFTR_edge;
 
@@ -120,9 +105,10 @@ static ir_node *reduce(ir_node *orig, ir_node *iv, ir_node *rc, iv_env *env);
 /**
  * Compare two LFTR edges.
  */
-static int LFTR_cmp(const void *e1, const void *e2, size_t size) {
-	const LFTR_edge *l1 = e1;
-	const LFTR_edge *l2 = e2;
+static int LFTR_cmp(const void *e1, const void *e2, size_t size)
+{
+	const LFTR_edge *l1 = (const LFTR_edge*)e1;
+	const LFTR_edge *l2 = (const LFTR_edge*)e2;
 	(void) size;
 
 	return l1->src != l2->src;
@@ -130,19 +116,29 @@ static int LFTR_cmp(const void *e1, const void *e2, size_t size) {
 
 /**
  * Find a LFTR edge.
+ *
+ * @param src  the source node of the transition
  */
-static LFTR_edge *LFTR_find(ir_node *src, iv_env *env) {
+static LFTR_edge *LFTR_find(ir_node *src, iv_env *env)
+{
 	LFTR_edge key;
 
 	key.src  = src;
 
-	return set_find(env->lftr_edges, &key, sizeof(key), HASH_PTR(src));
+	return set_find(LFTR_edge, env->lftr_edges, &key, sizeof(key), hash_ptr(src));
 }
 
 /**
  * Add a LFTR edge.
+ *
+ * @param src   the source node of the edge
+ * @param dst   the destination node of the edge
+ * @param code  the opcode of the transformed transition
+ * @param rc    the region const used in the transition
+ * @param env   the environment
  */
-static void LFTR_add(ir_node *src, ir_node *dst, ir_opcode code, ir_node *rc, iv_env *env) {
+static void LFTR_add(ir_node *src, ir_node *dst, unsigned code, ir_node *rc, iv_env *env)
+{
 	LFTR_edge key;
 
 	key.src  = src;
@@ -154,28 +150,34 @@ static void LFTR_add(ir_node *src, ir_node *dst, ir_opcode code, ir_node *rc, iv
 	 * There might be more than one edge here. This is rather bad
 	 * because we currently store only one.
 	 */
-//	assert(LFTR_find(src, env) == NULL);
-	set_insert(env->lftr_edges, &key, sizeof(key), HASH_PTR(src));
+	(void)set_insert(LFTR_edge, env->lftr_edges, &key, sizeof(key), hash_ptr(src));
 }
 
 /**
- * Gets the node_entry of a node
+ * Gets the node_entry of a node.
+ *
+ * @param irn  the node
+ * @param env  the environment
  */
-static node_entry *get_irn_ne(ir_node *irn, iv_env *env) {
-	node_entry *e = get_irn_link(irn);
+static node_entry *get_irn_ne(ir_node *irn, iv_env *env)
+{
+	node_entry *e = (node_entry*)get_irn_link(irn);
 
-	if (! e) {
-		e = obstack_alloc(&env->obst, sizeof(*e));
-		memset(e, 0, sizeof(*e));
+	if (e == NULL) {
+		e = OALLOCZ(&env->obst, node_entry);
 		set_irn_link(irn, e);
 	}
 	return e;
 }
 
 /**
- * Gets the scc from an IV.
+ * Gets the scc from an induction variable.
+ *
+ * @param iv   any node of the induction variable
+ * @param env  the environment
  */
-static scc *get_iv_scc(ir_node *iv, iv_env *env) {
+static scc *get_iv_scc(ir_node *iv, iv_env *env)
+{
 	node_entry *e = get_irn_ne(iv, env);
 	return e->pscc;
 }
@@ -188,7 +190,8 @@ static scc *get_iv_scc(ir_node *iv, iv_env *env) {
  *
  * @returns the header if it is one, NULL else
  */
-static ir_node *is_iv(ir_node *irn, iv_env *env) {
+static ir_node *is_iv(ir_node *irn, iv_env *env)
+{
 	return get_irn_ne(irn, env)->header;
 }
 
@@ -199,7 +202,8 @@ static ir_node *is_iv(ir_node *irn, iv_env *env) {
  * @param irn           the node to check
  * @param header_block  the header block of the induction variable
  */
-static int is_rc(ir_node *irn, ir_node *header_block) {
+static int is_rc(ir_node *irn, ir_node *header_block)
+{
 	ir_node *block = get_nodes_block(irn);
 
 	return (block != header_block) && block_dominates(block, header_block);
@@ -208,9 +212,10 @@ static int is_rc(ir_node *irn, ir_node *header_block) {
 /**
  * Set compare function for the quad set.
  */
-static int quad_cmp(const void *e1, const void *e2, size_t size) {
-	const quadruple_t *c1 = e1;
-	const quadruple_t *c2 = e2;
+static int quad_cmp(const void *e1, const void *e2, size_t size)
+{
+	const quadruple_t *c1 = (const quadruple_t*)e1;
+	const quadruple_t *c2 = (const quadruple_t*)e2;
 	(void) size;
 
 	return c1->code != c2->code || c1->op1 != c2->op1 || c1->op2 != c2->op2;
@@ -226,15 +231,15 @@ static int quad_cmp(const void *e1, const void *e2, size_t size) {
  *
  * @return the already reduced node or NULL if this operation is not yet reduced
  */
-static ir_node *search(ir_opcode code, ir_node *op1, ir_node *op2, iv_env *env) {
+static ir_node *search(unsigned code, ir_node *op1, ir_node *op2, iv_env *env)
+{
 	quadruple_t key, *entry;
 
 	key.code = code;
 	key.op1 = op1;
 	key.op2 = op2;
 
-	entry = set_find(env->quad_map, &key, sizeof(key),
-	                 (code * 9) ^ HASH_PTR(op1) ^HASH_PTR(op2));
+	entry = set_find(quadruple_t, env->quad_map, &key, sizeof(key), (code * 9) ^ hash_ptr(op1) ^ hash_ptr(op2));
 	if (entry)
 		return entry->res;
 	return NULL;
@@ -249,7 +254,8 @@ static ir_node *search(ir_opcode code, ir_node *op1, ir_node *op2, iv_env *env)
  * @param result  the result of the reduced operation
  * @param env     the environment
  */
-static void add(ir_opcode code, ir_node *op1, ir_node *op2, ir_node *result, iv_env *env) {
+static void add(unsigned code, ir_node *op1, ir_node *op2, ir_node *result, iv_env *env)
+{
 	quadruple_t key;
 
 	key.code = code;
@@ -257,8 +263,7 @@ static void add(ir_opcode code, ir_node *op1, ir_node *op2, ir_node *result, iv_
 	key.op2  = op2;
 	key.res  = result;
 
-	set_insert(env->quad_map, &key, sizeof(key),
-	           (code * 9) ^ HASH_PTR(op1) ^HASH_PTR(op2));
+	(void)set_insert(quadruple_t, env->quad_map, &key, sizeof(key), (code * 9) ^ hash_ptr(op1) ^ hash_ptr(op2));
 }
 
 /**
@@ -272,7 +277,8 @@ static void add(ir_opcode code, ir_node *op1, ir_node *op2, ir_node *result, iv_
  * that either block1 dominates block2 or vice versa. So, just return
  * the "smaller" one.
  */
-static ir_node *find_location(ir_node *block1, ir_node *block2) {
+static ir_node *find_location(ir_node *block1, ir_node *block2)
+{
 	if (block_dominates(block1, block2))
 		return block2;
 	assert(block_dominates(block2, block1));
@@ -290,24 +296,23 @@ static ir_node *find_location(ir_node *block1, ir_node *block2) {
  *
  * @return the newly created node
  */
-static ir_node *do_apply(ir_opcode code, dbg_info *db, ir_node *op1, ir_node *op2, ir_mode *mode) {
-	ir_graph *irg = current_ir_graph;
+static ir_node *do_apply(unsigned code, dbg_info *db, ir_node *op1, ir_node *op2, ir_mode *mode)
+{
 	ir_node *result;
 	ir_node *block = find_location(get_nodes_block(op1), get_nodes_block(op2));
 
 	switch (code) {
 	case iro_Mul:
-		result = new_rd_Mul(db, irg, block, op1, op2, mode);
+		result = new_rd_Mul(db, block, op1, op2, mode);
 		break;
 	case iro_Add:
-		result = new_rd_Add(db, irg, block, op1, op2, mode);
+		result = new_rd_Add(db, block, op1, op2, mode);
 		break;
 	case iro_Sub:
-		result = new_rd_Sub(db, irg, block, op1, op2, mode);
+		result = new_rd_Sub(db, block, op1, op2, mode);
 		break;
 	default:
 		panic("Unsupported opcode");
-		result = NULL;
 	}
 	return result;
 }
@@ -323,8 +328,9 @@ static ir_node *do_apply(ir_opcode code, dbg_info *db, ir_node *op1, ir_node *op
  *
  * @return the newly created node
  */
-static ir_node *apply(ir_node *header, ir_node *orig, ir_node *op1, ir_node *op2, iv_env *env) {
-	ir_opcode code = get_irn_opcode(orig);
+static ir_node *apply(ir_node *header, ir_node *orig, ir_node *op1, ir_node *op2, iv_env *env)
+{
+	unsigned code = get_irn_opcode(orig);
 	ir_node *result = search(code, op1, op2, env);
 
 	if (result == NULL) {
@@ -357,22 +363,31 @@ static ir_node *apply(ir_node *header, ir_node *orig, ir_node *op1, ir_node *op2
  *
  * @return the reduced node
  */
-static ir_node *reduce(ir_node *orig, ir_node *iv, ir_node *rc, iv_env *env) {
-	ir_opcode code = get_irn_opcode(orig);
+static ir_node *reduce(ir_node *orig, ir_node *iv, ir_node *rc, iv_env *env)
+{
+	unsigned code = get_irn_opcode(orig);
 	ir_node *result = search(code, iv, rc, env);
 
+	/* check if we have already done this operation on the iv */
 	if (result == NULL) {
 		node_entry *e, *iv_e;
-		int i, n;
+		int i;
 		ir_mode *mode = get_irn_mode(orig);
 
 		result = exact_copy(iv);
 
-		/* Beware: we must always create a new induction variable with the same mode
-		   as the node we are replacing. Especially this means the mode might be changed
-		   from P to I and back. This is always possible, because we have only Phi, Add
-		   and Sub nodes. */
-		set_irn_mode(result, mode);
+		if (get_irn_mode(result) != mode) {
+			/*
+			 * Beware: we must always create a new induction variable with the same mode
+			 * as the node we are replacing. Especially this means the mode might be changed
+			 * from P to I and back. This is always possible, because we have only Phi, Add
+			 * and Sub nodes.
+			 * However, this might lead to AddIs(Iu,Is) which we must fix. The best way to do this
+			 * seems to be a post-pass, or we might end with useless Conv's.
+			 */
+			set_irn_mode(result, mode);
+			env->need_postpass = 1;
+		}
 		add(code, iv, rc, result, env);
 		DB((dbg, LEVEL_3, "   Created new %+F for %+F (%s %+F)\n", result, iv,
 			get_irn_opname(orig), rc));
@@ -384,8 +399,7 @@ static ir_node *reduce(ir_node *orig, ir_node *iv, ir_node *rc, iv_env *env) {
 		/* create the LFTR edge */
 		LFTR_add(iv, result, code, rc, env);
 
-		n = get_irn_arity(result);
-		for (i = 0; i < n; ++i) {
+		for (i = get_irn_arity(result) - 1; i >= 0; --i) {
 			ir_node *o = get_irn_n(result, i);
 
 			e = get_irn_ne(o, env);
@@ -395,8 +409,7 @@ static ir_node *reduce(ir_node *orig, ir_node *iv, ir_node *rc, iv_env *env) {
 				o = apply(iv_e->header, orig, o, rc, env);
 			set_irn_n(result, i, o);
 		}
-	}
-	else {
+	} else {
 		DB((dbg, LEVEL_3, "   Already Created %+F for %+F (%s %+F)\n", result, iv,
 			get_irn_opname(orig), rc));
 	}
@@ -406,7 +419,8 @@ static ir_node *reduce(ir_node *orig, ir_node *iv, ir_node *rc, iv_env *env) {
 /**
  * Update the scc for a newly created IV.
  */
-static void update_scc(ir_node *iv, node_entry *e, iv_env *env) {
+static void update_scc(ir_node *iv, node_entry *e, iv_env *env)
+{
 	scc     *pscc   = e->pscc;
 	ir_node *header = e->header;
 	waitq    *wq = new_waitq();
@@ -415,7 +429,7 @@ static void update_scc(ir_node *iv, node_entry *e, iv_env *env) {
 	pscc->head = NULL;
 	waitq_put(wq, iv);
 	do {
-		ir_node    *irn = waitq_get(wq);
+		ir_node    *irn = (ir_node*)waitq_get(wq);
 		node_entry *ne  = get_irn_ne(irn, env);
 		int        i;
 
@@ -440,14 +454,17 @@ static void update_scc(ir_node *iv, node_entry *e, iv_env *env) {
 }
 
 /**
- * The Replace operation.
+ * The Replace operation. We found a node representing iv (+,-,*) rc
+ * that can be removed by replacing the induction variable iv by a new
+ * one that 'applies' the operation 'irn'.
  *
  * @param irn   the node that will be replaced
  * @param iv    the induction variable
  * @param rc    the region constant
  * @param env   the environment
  */
-static int replace(ir_node *irn, ir_node *iv, ir_node *rc, iv_env *env) {
+static int replace(ir_node *irn, ir_node *iv, ir_node *rc, iv_env *env)
+{
 	ir_node *result;
 
 	DB((dbg, LEVEL_2, "  Replacing %+F\n", irn));
@@ -456,12 +473,11 @@ static int replace(ir_node *irn, ir_node *iv, ir_node *rc, iv_env *env) {
 	if (result != irn) {
 		node_entry *e;
 
-		hook_strength_red(current_ir_graph, irn);
+		hook_strength_red(get_irn_irg(irn), irn);
 		exchange(irn, result);
 		e = get_irn_ne(result, env);
 		if (e->pscc == NULL) {
-			e->pscc = obstack_alloc(&env->obst, sizeof(*e->pscc));
-			memset(e->pscc, 0, sizeof(*e->pscc));
+			e->pscc = OALLOCZ(&env->obst, scc);
 			update_scc(result, e, env);
 		}
 		++env->replaced;
@@ -470,38 +486,14 @@ static int replace(ir_node *irn, ir_node *iv, ir_node *rc, iv_env *env) {
 	return 0;
 }
 
-#if 0
-/**
- * check if a given node is a mul with 2, 4, 8
- */
-static int is_x86_shift_const(ir_node *mul) {
-	ir_node *rc;
-
-	if (! is_Mul(mul))
-		return 0;
-
-	/* normalization put constants on the right side */
-	rc = get_Mul_right(mul);
-	if (is_Const(rc)) {
-		tarval *tv = get_Const_tarval(rc);
-
-		if (tarval_is_long(tv)) {
-			long value = get_tarval_long(tv);
-
-			if (value == 2 || value == 4 || value == 8) {
-				/* do not reduce multiplications by 2, 4, 8 */
-				return 1;
-			}
-		}
-	}
-	return 0;
-}
-#endif
-
 /**
  * Check if an IV represents a counter with constant limits.
+ *
+ * @param iv    any node of the induction variable
+ * @param env   the environment
  */
-static int is_counter_iv(ir_node *iv, iv_env *env) {
+static int is_counter_iv(ir_node *iv, iv_env *env)
+{
 	node_entry *e         = get_irn_ne(iv, env);
 	scc        *pscc      = e->pscc;
 	ir_node    *have_init = NULL;
@@ -562,18 +554,22 @@ static int is_counter_iv(ir_node *iv, iv_env *env) {
 
 /**
  * Check the users of an induction variable for register pressure.
+ *
+ * @param iv    any node of the induction variable
+ * @param env   the environment
+ *
+ * @return non-zero if the register pressure is estimated
+ *         to not increase, zero else
  */
-static int check_users_for_reg_pressure(ir_node *iv, iv_env *env) {
-	ir_node    *irn, *header;
+static int check_users_for_reg_pressure(ir_node *iv, iv_env *env)
+{
+	ir_node    *irn;
 	ir_node    *have_user = NULL;
 	ir_node    *have_cmp  = NULL;
 	node_entry *e         = get_irn_ne(iv, env);
 	scc        *pscc      = e->pscc;
 
-	header = e->header;
 	for (irn = pscc->head; irn != NULL; irn = e->next) {
-		const ir_edge_t *edge;
-
 		foreach_out_edge(irn, edge) {
 			ir_node    *user = get_edge_src_irn(edge);
 			node_entry *ne = get_irn_ne(user, env);
@@ -615,7 +611,7 @@ static int check_users_for_reg_pressure(ir_node *iv, iv_env *env) {
 	 *
 	 * For now our capabilities for doing linear function test
 	 * are limited, so check if the iv has the right form: Only ONE
-	 * phi, only one Add/Sub with a Const
+	 * Phi, only one Add/Sub with a Const.
 	 */
 	if (! is_counter_iv(iv, env))
 		return 0;
@@ -635,10 +631,11 @@ static int check_users_for_reg_pressure(ir_node *iv, iv_env *env) {
  *
  * @return non-zero if irn should be Replace'd
  */
-static int check_replace(ir_node *irn, iv_env *env) {
+static int check_replace(ir_node *irn, iv_env *env)
+{
 	ir_node   *left, *right, *iv, *rc;
 	ir_op     *op  = get_irn_op(irn);
-	ir_opcode code = get_op_code(op);
+	unsigned  code = get_op_code(op);
 	ir_node   *liv, *riv;
 
 	switch (code) {
@@ -661,7 +658,7 @@ static int check_replace(ir_node *irn, iv_env *env) {
 		}
 
 		if (iv) {
-			if (env->flags & osr_flag_keep_reg_pressure) {
+			if (env->osr_flags & osr_flag_keep_reg_pressure) {
 				if (! check_users_for_reg_pressure(iv, env))
 					return 0;
 			}
@@ -680,7 +677,8 @@ static int check_replace(ir_node *irn, iv_env *env) {
  * @param pscc  a SCC
  * @param env   the environment
  */
-static void classify_iv(scc *pscc, iv_env *env) {
+static void classify_iv(scc *pscc, iv_env *env)
+{
 	ir_node *irn, *next, *header = NULL;
 	node_entry *b, *h = NULL;
 	int j, only_phi, num_outside;
@@ -688,7 +686,7 @@ static void classify_iv(scc *pscc, iv_env *env) {
 
 	/* find the header block for this scc */
 	for (irn = pscc->head; irn; irn = next) {
-		node_entry *e = get_irn_link(irn);
+		node_entry *e = (node_entry*)get_irn_link(irn);
 		ir_node *block = get_nodes_block(irn);
 
 		next = e->next;
@@ -715,8 +713,26 @@ static void classify_iv(scc *pscc, iv_env *env) {
 
 		next = e->next;
 		switch (get_irn_opcode(irn)) {
-		case iro_Add:
 		case iro_Sub:
+			only_phi = 0;
+			{
+				ir_node    *left        = get_Sub_left(irn);
+				node_entry *left_entry  = get_irn_ne(left, env);
+				ir_node    *right       = get_Sub_right(irn);
+				node_entry *right_entry = get_irn_ne(right, env);
+
+				if (left_entry->pscc != e->pscc ||
+				    (right_entry->pscc != e->pscc && !is_rc(right, header))) {
+					/*
+					 * Not an induction variable.
+					 * Region constant are only allowed on right hand side.
+					 */
+					goto fail;
+				}
+			}
+			break;
+
+		case iro_Add:
 			only_phi = 0;
 			/* fall through */
 		case iro_Phi:
@@ -780,22 +796,23 @@ fail:
 }
 
 /**
- * Process a SCC for the operator strength reduction.
+ * Process an SCC for the operator strength reduction.
  *
  * @param pscc  the SCC
  * @param env   the environment
  */
-static void process_scc(scc *pscc, iv_env *env) {
+static void process_scc(scc *pscc, iv_env *env)
+{
 	ir_node *head = pscc->head;
-	node_entry *e = get_irn_link(head);
+	node_entry *e = (node_entry*)get_irn_link(head);
 
 #ifdef DEBUG_libfirm
 	{
 		ir_node *irn, *next;
 
 		DB((dbg, LEVEL_4, " SCC at %p:\n ", pscc));
-		for (irn = pscc->head; irn; irn = next) {
-			node_entry *e = get_irn_link(irn);
+		for (irn = pscc->head; irn != NULL; irn = next) {
+			node_entry *e = (node_entry*)get_irn_link(irn);
 
 			next = e->next;
 
@@ -815,13 +832,17 @@ static void process_scc(scc *pscc, iv_env *env) {
 
 /**
  * If an SCC is a Phi only cycle, remove it.
+ *
+ * @param pscc  an SCC that consists of Phi nodes only
+ * @param env   the environment
  */
-static void remove_phi_cycle(scc *pscc, iv_env *env) {
+static void remove_phi_cycle(scc *pscc, iv_env *env)
+{
 	ir_node *irn, *next;
 	int j;
 	ir_node *out_rc;
 
-	/* check if this scc contains only Phi, Add or Sub nodes */
+	/* check if this scc contains only Phi nodes */
 	out_rc      = NULL;
 	for (irn = pscc->head; irn; irn = next) {
 		node_entry *e = get_irn_ne(irn, env);
@@ -857,14 +878,15 @@ static void remove_phi_cycle(scc *pscc, iv_env *env) {
 }
 
 /**
- * Process a SCC for the Phi cycle removement.
+ * Process a SCC for the Phi cycle remove.
  *
  * @param pscc  the SCC
  * @param env   the environment
  */
-static void process_phi_only_scc(scc *pscc, iv_env *env) {
+static void process_phi_only_scc(scc *pscc, iv_env *env)
+{
 	ir_node *head = pscc->head;
-	node_entry *e = get_irn_link(head);
+	node_entry *e = (node_entry*)get_irn_link(head);
 
 #ifdef DEBUG_libfirm
 	{
@@ -872,7 +894,7 @@ static void process_phi_only_scc(scc *pscc, iv_env *env) {
 
 		DB((dbg, LEVEL_4, " SCC at %p:\n ", pscc));
 		for (irn = pscc->head; irn; irn = next) {
-			node_entry *e = get_irn_link(irn);
+			node_entry *e = (node_entry*)get_irn_link(irn);
 
 			next = e->next;
 
@@ -893,11 +915,12 @@ static void process_phi_only_scc(scc *pscc, iv_env *env) {
  * @param env   the environment
  * @param n     the node to push
  */
-static void push(iv_env *env, ir_node *n) {
+static void push(iv_env *env, ir_node *n)
+{
 	node_entry *e;
 
 	if (env->tos == ARR_LEN(env->stack)) {
-		int nlen = ARR_LEN(env->stack) * 2;
+		size_t nlen = ARR_LEN(env->stack) * 2;
 		ARR_RESIZE(ir_node *, env->stack, nlen);
 	}
 	env->stack[env->tos++] = n;
@@ -906,7 +929,7 @@ static void push(iv_env *env, ir_node *n) {
 }
 
 /**
- * pop a node from the stack
+ * Pop a node from the stack.
  *
  * @param env   the environment
  *
@@ -940,11 +963,10 @@ static void dfs(ir_node *irn, iv_env *env)
 		for (i = 0; i < n; ++i) {
 			ir_node *pred = get_irn_n(irn, i);
 
-			if (irn_not_visited(pred))
+			if (!irn_visited(pred))
 				dfs(pred, env);
 		}
-	}
-	else {
+	} else {
 		ir_node *block = get_nodes_block(irn);
 
 		node->DFSnum = env->nextDFSnum++;
@@ -952,7 +974,7 @@ static void dfs(ir_node *irn, iv_env *env)
 		push(env, irn);
 
 		/* handle the block */
-		if (irn_not_visited(block))
+		if (!irn_visited(block))
 			dfs(block, env);
 
 		n = get_irn_arity(irn);
@@ -960,7 +982,7 @@ static void dfs(ir_node *irn, iv_env *env)
 			ir_node *pred = get_irn_n(irn, i);
 			node_entry *o = get_irn_ne(pred, env);
 
-			if (irn_not_visited(pred)) {
+			if (!irn_visited(pred)) {
 				dfs(pred, env);
 				node->low = MIN(node->low, o->low);
 			}
@@ -968,10 +990,9 @@ static void dfs(ir_node *irn, iv_env *env)
 				node->low = MIN(o->DFSnum, node->low);
 		}
 		if (node->low == node->DFSnum) {
-			scc *pscc = obstack_alloc(&env->obst, sizeof(*pscc));
+			scc *pscc = OALLOCZ(&env->obst, scc);
 			ir_node *x;
 
-			memset(pscc, 0, sizeof(*pscc));
 			do {
 				node_entry *e;
 
@@ -993,63 +1014,40 @@ static void dfs(ir_node *irn, iv_env *env)
  * @param irg  the graph to process
  * @param env  the environment
  */
-static void do_dfs(ir_graph *irg, iv_env *env) {
-	ir_graph *rem = current_ir_graph;
-	ir_node *end = get_irg_end(irg);
-	int i, n;
+static void do_dfs(ir_graph *irg, iv_env *env)
+{
+	ir_node  *end = get_irg_end(irg);
+	int i;
 
 	ir_reserve_resources(irg, IR_RESOURCE_IRN_VISITED);
 
-	current_ir_graph = irg;
 	inc_irg_visited(irg);
 
 	/* visit all visible nodes */
 	dfs(end, env);
 
 	/* visit the keep-alives */
-	n = get_End_n_keepalives(end);
-	for (i = 0; i < n; ++i) {
+	for (i = get_End_n_keepalives(end) - 1; i >= 0; --i) {
 		ir_node *ka = get_End_keepalive(end, i);
 
-		if (irn_not_visited(ka))
+		if (!irn_visited(ka))
 			dfs(ka, env);
 	}
 
 	ir_free_resources(irg, IR_RESOURCE_IRN_VISITED);
-
-	current_ir_graph = rem;
 }
 
 /**
  * Post-block-walker: assign the post-order number.
  */
-static void assign_po(ir_node *block, void *ctx) {
-	iv_env *env = ctx;
+static void assign_po(ir_node *block, void *ctx)
+{
+	iv_env *env = (iv_env*)ctx;
 	node_entry *e = get_irn_ne(block, env);
 
 	e->POnum = env->POnum++;
 }
 
-/**
- * Follows the LFTR edges and return the last node in the chain.
- *
- * @param irn  the node that should be followed
- * @param env  the IV environment
- *
- * @note
- * In the current implementation only the last edge is stored, so
- * only one chain exists. That's why we might miss some opportunities.
- */
-static ir_node *followEdges(ir_node *irn, iv_env *env) {
-	for (;;) {
-		LFTR_edge *e = LFTR_find(irn, env);
-		if (e)
-			irn = e->dst;
-		else
-			return irn;
-	}
-}
-
 /**
  * Apply one LFTR edge operation.
  * Return NULL if the transformation cannot be done safely without
@@ -1067,11 +1065,13 @@ static ir_node *followEdges(ir_node *irn, iv_env *env) {
  * In the current implementation only the last edge is stored, so
  * only one chain exists. That's why we might miss some opportunities.
  */
-static ir_node *applyOneEdge(ir_node *iv, ir_node *rc, LFTR_edge *e, iv_env *env) {
-	if (env->flags & osr_flag_lftr_with_ov_check) {
-		tarval *tv_l, *tv_r, *tv, *tv_init, *tv_incr;
+static ir_node *applyOneEdge(ir_node *iv, ir_node *rc, LFTR_edge *e, iv_env *env)
+{
+	if (env->osr_flags & osr_flag_lftr_with_ov_check) {
+		ir_tarval *tv_l, *tv_r, *tv, *tv_init, *tv_incr, *tv_end;
 		tarval_int_overflow_mode_t ovmode;
 		scc *pscc;
+		ir_graph *irg;
 
 		if (! is_counter_iv(iv, env)) {
 			DB((dbg, LEVEL_4, " not counter IV"));
@@ -1080,6 +1080,11 @@ static ir_node *applyOneEdge(ir_node *iv, ir_node *rc, LFTR_edge *e, iv_env *env
 
 		/* overflow can only be decided for Consts */
 		if (! is_Const(e->rc)) {
+			if (e->code == iro_Add && mode_is_reference(get_irn_mode(e->rc))) {
+				/* However we allow ONE Pointer Add, as pointer arithmetic with wrap
+				   around is undefined anyway */
+				return do_apply(e->code, NULL, rc, e->rc, get_irn_mode(e->rc));
+			}
 			DB((dbg, LEVEL_4, " = UNKNOWN (%+F)", e->rc));
 			return NULL;
 		}
@@ -1119,25 +1124,31 @@ static ir_node *applyOneEdge(ir_node *iv, ir_node *rc, LFTR_edge *e, iv_env *env
 			break;
 		default:
 			panic("Unsupported opcode");
-			tv = tarval_bad;
+		}
+
+		if (tv == tarval_bad || tv_init == tarval_bad) {
+			tarval_set_integer_overflow_mode(ovmode);
+			DB((dbg, LEVEL_4, " = OVERFLOW"));
+			return NULL;
 		}
 
 		if (pscc->code == iro_Add) {
-			tv = tarval_add(tv, tv_incr);
+			tv_end = tarval_add(tv, tv_incr);
 		} else {
 			assert(pscc->code == iro_Sub);
-			tv = tarval_sub(tv, tv_incr, NULL);
+			tv_end = tarval_sub(tv, tv_incr, NULL);
 		}
 
 		tarval_set_integer_overflow_mode(ovmode);
 
-		if (tv == tarval_bad || tv_init == tarval_bad) {
+		if (tv_end == tarval_bad) {
 			DB((dbg, LEVEL_4, " = OVERFLOW"));
 			return NULL;
 		}
-		return new_r_Const(current_ir_graph, get_irn_n(rc, -1), get_tarval_mode(tv), tv);
+		irg = get_irn_irg(iv);
+		return new_r_Const(irg, tv);
 	}
-	return do_apply(e->code, NULL, rc, e->rc, get_irn_mode(rc));
+	return do_apply(e->code, NULL, rc, e->rc, get_irn_mode(e->dst));
 }
 
 /**
@@ -1146,15 +1157,18 @@ static ir_node *applyOneEdge(ir_node *iv, ir_node *rc, LFTR_edge *e, iv_env *env
  * Return NULL if the transformation cannot be done safely without
  * an Overflow.
  *
- * @param iv   the IV node that starts the LFTR edge chain
+ * @param pIV  points to the IV node that starts the LFTR edge chain
+ *             after translation points to the new IV
  * @param rc   the region constant that should be translated
  * @param env  the IV environment
  *
  * @return the translated region constant or NULL
  *         if the translation was not possible
  */
-static ir_node *applyEdges(ir_node *iv, ir_node *rc, iv_env *env) {
-	if (env->flags & osr_flag_lftr_with_ov_check) {
+static ir_node *applyEdges(ir_node **pIV, ir_node *rc, iv_env *env)
+{
+	ir_node *iv = *pIV;
+	if (env->osr_flags & osr_flag_lftr_with_ov_check) {
 		/* overflow can only be decided for Consts */
 		if (! is_counter_iv(iv, env)) {
 			DB((dbg, LEVEL_4, "not counter IV\n", rc));
@@ -1169,14 +1183,14 @@ static ir_node *applyEdges(ir_node *iv, ir_node *rc, iv_env *env) {
 
 	for (; rc;) {
 		LFTR_edge *e = LFTR_find(iv, env);
-		if (e) {
+		if (e != NULL) {
 			rc = applyOneEdge(iv, rc, e, env);
 			iv = e->dst;
-		}
-		else
+		} else
 			break;
 	}
 	DB((dbg, LEVEL_3, "\n"));
+	*pIV = iv;
 	return rc;
 }
 
@@ -1184,8 +1198,9 @@ static ir_node *applyEdges(ir_node *iv, ir_node *rc, iv_env *env) {
  * Walker, finds Cmp(iv, rc) or Cmp(rc, iv)
  * and tries to optimize them.
  */
-static void do_lftr(ir_node *cmp, void *ctx) {
-	iv_env *env = ctx;
+static void do_lftr(ir_node *cmp, void *ctx)
+{
+	iv_env *env = (iv_env*)ctx;
 	ir_node *left, *right, *liv, *riv;
 	ir_node *iv, *rc;
 	ir_node *nleft = NULL, *nright = NULL;
@@ -1201,18 +1216,14 @@ static void do_lftr(ir_node *cmp, void *ctx) {
 	if (liv && is_rc(right, liv)) {
 		iv = left; rc = right;
 
-		nright = applyEdges(iv, rc, env);
-		if (nright && nright != rc) {
-			nleft = followEdges(iv, env);
-		}
+		nright = applyEdges(&iv, rc, env);
+		nleft  = iv;
 	}
 	else if (riv && is_rc(left, riv)) {
 		iv = right; rc = left;
 
-		nleft = applyEdges(iv, rc, env);
-		if (nleft && nleft != rc) {
-			nright = followEdges(iv, env);
-		}
+		nleft  = applyEdges(&iv, rc, env);
+		nright = iv;
 	}
 
 	if (nleft && nright) {
@@ -1229,139 +1240,215 @@ static void do_lftr(ir_node *cmp, void *ctx) {
  * @param irg   the graph that should be optimized
  * @param env   the IV environment
  */
-static void lftr(ir_graph *irg, iv_env *env) {
+static void lftr(ir_graph *irg, iv_env *env)
+{
 	irg_walk_graph(irg, NULL, do_lftr, env);
 }
 
-/**
- * Pre-walker: set all node links to NULL and fix the
- * block of Proj nodes.
- */
-static void clear_and_fix(ir_node *irn, void *env)
+/* Remove any Phi cycles with only one real input. */
+void remove_phi_cycles(ir_graph *irg)
 {
-	(void) env;
-	set_irn_link(irn, NULL);
-
-	if (is_Proj(irn)) {
-		ir_node *pred = get_Proj_pred(irn);
-		set_nodes_block(irn, get_nodes_block(pred));
-	}
-}
-
-/* Performs Operator Strength Reduction for the passed graph. */
-void opt_osr(ir_graph *irg, unsigned flags) {
-	iv_env   env;
-	ir_graph *rem;
-	int      edges;
-
-	if (! get_opt_strength_red()) {
-		/* only kill Phi cycles  */
-		remove_phi_cycles(irg);
-		return;
-	}
+	iv_env env;
 
-	rem = current_ir_graph;
-	current_ir_graph = irg;
+	assure_irg_properties(irg,
+		IR_GRAPH_PROPERTY_CONSISTENT_DOMINANCE
+		| IR_GRAPH_PROPERTY_CONSISTENT_OUTS
+		| IR_GRAPH_PROPERTY_CONSISTENT_OUT_EDGES);
 
-	FIRM_DBG_REGISTER(dbg, "firm.opt.osr");
+	FIRM_DBG_REGISTER(dbg, "firm.opt.remove_phi");
 
-	DB((dbg, LEVEL_1, "Doing Operator Strength Reduction for %+F\n", irg));
+	DB((dbg, LEVEL_1, "Doing Phi cycle removement for %+F\n", irg));
 
 	obstack_init(&env.obst);
 	env.stack         = NEW_ARR_F(ir_node *, 128);
 	env.tos           = 0;
 	env.nextDFSnum    = 0;
 	env.POnum         = 0;
-	env.quad_map      = new_set(quad_cmp, 64);
-	env.lftr_edges    = new_set(LFTR_cmp, 64);
+	env.quad_map      = NULL;
+	env.lftr_edges    = NULL;
 	env.replaced      = 0;
 	env.lftr_replaced = 0;
-	env.flags         = flags;
-	env.process_scc   = process_scc;
+	env.osr_flags     = 0;
+	env.need_postpass = 0;
+	env.process_scc   = process_phi_only_scc;
 
 	/* Clear all links and move Proj nodes into the
-	   the same block as it's predecessors.
-	   This can improve the placement of new nodes.
+	 * the same block as their predecessors.
+	 * This can improve the placement of new nodes.
 	 */
-	irg_walk_graph(irg, NULL, clear_and_fix, NULL);
-
-	/* we need dominance */
-	assure_doms(irg);
-
-	edges = edges_assure(irg);
+	irg_walk_graph(irg, NULL, firm_clear_link, NULL);
 
 	/* calculate the post order number for blocks. */
-	irg_block_edges_walk(get_irg_start_block(irg), NULL, assign_po, &env);
+	irg_out_block_walk(get_irg_start_block(irg), NULL, assign_po, &env);
 
 	/* calculate the SCC's and drive OSR. */
+	ir_reserve_resources(irg, IR_RESOURCE_IRN_LINK);
 	do_dfs(irg, &env);
+	ir_free_resources(irg, IR_RESOURCE_IRN_LINK);
 
 	if (env.replaced) {
-		/* try linear function test replacements */
-		//lftr(irg, &env); // currently buggy :-(
-		(void) lftr;
-
-		set_irg_outs_inconsistent(irg);
-		DB((dbg, LEVEL_1, "Replacements: %u + %u (lftr)\n\n", env.replaced, env.lftr_replaced));
+		DB((dbg, LEVEL_1, "remove_phi_cycles: %u Cycles removed\n\n",
+		    env.replaced));
 	}
 
-	del_set(env.lftr_edges);
-	del_set(env.quad_map);
 	DEL_ARR_F(env.stack);
 	obstack_free(&env.obst, NULL);
 
-	if (! edges)
-		edges_deactivate(irg);
+	confirm_irg_properties(irg, IR_GRAPH_PROPERTIES_CONTROL_FLOW);
+}
 
-	current_ir_graph = rem;
+ir_graph_pass_t *remove_phi_cycles_pass(const char *name)
+{
+	return def_graph_pass(name ? name : "remove_phi_cycles", remove_phi_cycles);
 }
 
-/* Remove any Phi cycles with only one real input. */
-void remove_phi_cycles(ir_graph *irg) {
-	iv_env   env;
-	ir_graph *rem;
+/**
+ * Post-walker: fix Add and Sub nodes that where results of I<->P conversions.
+ */
+static void fix_adds_and_subs(ir_node *irn, void *ctx)
+{
+	(void) ctx;
 
-	rem = current_ir_graph;
-	current_ir_graph = irg;
+	if (is_Add(irn)) {
+		ir_mode *mode = get_irn_mode(irn);
 
-	FIRM_DBG_REGISTER(dbg, "firm.opt.remove_phi");
+		if (mode_is_int(mode)) {
+			ir_node *pred;
 
-	DB((dbg, LEVEL_1, "Doing Phi cycle removement for %+F\n", irg));
+			pred = get_Add_left(irn);
+			if (get_irn_mode(pred) != mode) {
+				ir_node *block = get_nodes_block(pred);
+
+				pred = new_r_Conv(block, pred, mode);
+				set_Add_left(irn, pred);
+			}
+			pred = get_Add_right(irn);
+			if (get_irn_mode(pred) != mode) {
+				ir_node *block = get_nodes_block(pred);
+
+				pred = new_r_Conv(block, pred, mode);
+				set_Add_right(irn, pred);
+			}
+		}
+	} else if (is_Sub(irn)) {
+		ir_mode *mode = get_irn_mode(irn);
+
+		if (mode_is_int(mode)) {
+			ir_node *left   = get_Sub_left(irn);
+			ir_node *right  = get_Sub_right(irn);
+			ir_mode *l_mode = get_irn_mode(left);
+			ir_mode *r_mode = get_irn_mode(right);
+
+			if (mode_is_int(l_mode) && mode_is_int(r_mode)) {
+				if (l_mode != mode) {
+					ir_node *block = get_nodes_block(left);
+
+					left = new_r_Conv(block, left, mode);
+					set_Sub_left(irn, left);
+				}
+				if (r_mode != mode) {
+					ir_node *block = get_nodes_block(right);
+
+					right = new_r_Conv(block, right, mode);
+					set_Sub_right(irn, right);
+				}
+			}
+		} else if (mode_is_reference(mode)) {
+			ir_node *left   = get_Sub_left(irn);
+			ir_node *right  = get_Sub_right(irn);
+			ir_mode *l_mode = get_irn_mode(left);
+			ir_mode *r_mode = get_irn_mode(right);
+			if (mode_is_int(l_mode)) {
+				/* Usually, Sub(I*,P) is an error, hence the verifier rejects it.
+				 * However, it is correct in this case, so add Conv to make verifier happy. */
+				ir_node *block = get_nodes_block(right);
+				ir_node *lconv = new_r_Conv(block, left, r_mode);
+				assert(mode_is_reference(r_mode));
+				set_Sub_left(irn, lconv);
+			}
+		}
+	}
+}
+
+/* Performs Operator Strength Reduction for the passed graph. */
+void opt_osr(ir_graph *irg, unsigned flags)
+{
+	iv_env env;
+
+	FIRM_DBG_REGISTER(dbg, "firm.opt.osr");
+
+	assure_irg_properties(irg,
+		IR_GRAPH_PROPERTY_CONSISTENT_DOMINANCE
+		| IR_GRAPH_PROPERTY_CONSISTENT_OUTS
+		| IR_GRAPH_PROPERTY_CONSISTENT_OUT_EDGES);
+
+	DB((dbg, LEVEL_1, "Doing Operator Strength Reduction for %+F\n", irg));
 
 	obstack_init(&env.obst);
 	env.stack         = NEW_ARR_F(ir_node *, 128);
 	env.tos           = 0;
 	env.nextDFSnum    = 0;
 	env.POnum         = 0;
-	env.quad_map      = NULL;
-	env.lftr_edges    = NULL;
+	env.quad_map      = new_set(quad_cmp, 64);
+	env.lftr_edges    = new_set(LFTR_cmp, 64);
 	env.replaced      = 0;
 	env.lftr_replaced = 0;
-	env.flags         = 0;
-	env.process_scc   = process_phi_only_scc;
+	env.osr_flags     = flags;
+	env.need_postpass = 0;
+	env.process_scc   = process_scc;
 
 	/* Clear all links and move Proj nodes into the
-	   the same block as it's predecessors.
-	   This can improve the placement of new nodes.
+	 * the same block as its predecessors.
+	 * This can improve the placement of new nodes.
 	 */
-	irg_walk_graph(irg, NULL, clear_and_fix, NULL);
+	irg_walk_graph(irg, NULL, firm_clear_link, NULL);
 
-	/* we need outs for calculating the post order */
-	assure_irg_outs(irg);
-
-	/* calculate the post order number for blocks. */
-	irg_out_block_walk(get_irg_start_block(irg), NULL, assign_po, &env);
+	irg_block_edges_walk(get_irg_start_block(irg), NULL, assign_po, &env);
 
 	/* calculate the SCC's and drive OSR. */
+	ir_reserve_resources(irg, IR_RESOURCE_IRN_LINK);
 	do_dfs(irg, &env);
 
 	if (env.replaced) {
-		set_irg_outs_inconsistent(irg);
-		DB((dbg, LEVEL_1, "remove_phi_cycles: %u Cycles removed\n\n", env.replaced));
+		if (env.need_postpass)
+			irg_walk_graph(irg, NULL, fix_adds_and_subs, &env);
+
+		/* try linear function test replacements */
+		lftr(irg, &env);
+		(void)lftr;
+
+		DB((dbg, LEVEL_1, "Replacements: %u + %u (lftr)\n\n", env.replaced, env.lftr_replaced));
 	}
+	ir_free_resources(irg, IR_RESOURCE_IRN_LINK);
 
+	del_set(env.lftr_edges);
+	del_set(env.quad_map);
 	DEL_ARR_F(env.stack);
 	obstack_free(&env.obst, NULL);
 
-	current_ir_graph = rem;
+	confirm_irg_properties(irg, IR_GRAPH_PROPERTIES_NONE);
+}
+
+typedef struct pass_t {
+	ir_graph_pass_t pass;
+	unsigned        flags;
+} pass_t;
+
+/**
+* Wrapper for running opt_osr() as an ir_graph pass.
+*/
+static int pass_wrapper(ir_graph *irg, void *context)
+{
+	pass_t *pass = (pass_t*)context;
+	opt_osr(irg, pass->flags);
+	return 0;
+}
+
+ir_graph_pass_t *opt_osr_pass(const char *name, unsigned flags)
+{
+	pass_t *pass = XMALLOCZ(pass_t);
+
+	pass->flags = flags;
+	return def_graph_pass_constructor(
+		&pass->pass, name ? name : "osr", pass_wrapper);
 }