xref: /dports/devel/libfirm/libfirm-1.21.0/ir/ir/iropt.c

/*
 * Copyright (C) 1995-2011 University of Karlsruhe.  All right reserved.
 *
 * This file is part of libFirm.
 *
 * This file may be distributed and/or modified under the terms of the
 * GNU General Public License version 2 as published by the Free Software
 * Foundation and appearing in the file LICENSE.GPL included in the
 * packaging of this file.
 *
 * Licensees holding valid libFirm Professional Edition licenses may use
 * this file in accordance with the libFirm Commercial License.
 * Agreement provided with the Software.
 *
 * This file is provided AS IS with NO WARRANTY OF ANY KIND, INCLUDING THE
 * WARRANTY OF DESIGN, MERCHANTABILITY AND FITNESS FOR A PARTICULAR
 * PURPOSE.
 */

/**
 * @file
 * @brief   iropt --- optimizations intertwined with IR construction.
 * @author  Christian Schaefer, Goetz Lindenmaier, Michael Beck
 */
#include "config.h"

#include <string.h>
#include <stdbool.h>

#include "irnode_t.h"
#include "irgraph_t.h"
#include "iredges_t.h"
#include "irmode_t.h"
#include "iropt_t.h"
#include "ircons_t.h"
#include "irgmod.h"
#include "irverify.h"
#include "iroptimize.h"
#include "tv_t.h"
#include "dbginfo_t.h"
#include "iropt_dbg.h"
#include "irflag_t.h"
#include "irhooks.h"
#include "irarch.h"
#include "hashptr.h"
#include "irtools.h"
#include "irhooks.h"
#include "array_t.h"
#include "vrp.h"
#include "firm_types.h"
#include "bitfiddle.h"
#include "be.h"
#include "error.h"

#include "entity_t.h"

static bool is_Or_Eor_Add(const ir_node *node)
{
	if (is_Or(node) || is_Eor(node) || is_Add(node)) {
		ir_node  *left      = get_binop_left(node);
		ir_node  *right     = get_binop_right(node);
		vrp_attr *vrp_left  = vrp_get_info(left);
		vrp_attr *vrp_right = vrp_get_info(right);
		if (vrp_left != NULL && vrp_right != NULL) {
			ir_tarval *vrp_val
				= tarval_and(vrp_left->bits_not_set, vrp_right->bits_not_set);
			return tarval_is_null(vrp_val);
		}
	}
	return false;
}

/**
 * Returns the tarval of a Const node or tarval_bad for all other nodes.
 */
static ir_tarval *default_value_of(const ir_node *n)
{
	if (is_Const(n))
		return get_Const_tarval(n); /* might return tarval_bad */
	else
		return tarval_bad;
}

value_of_func value_of_ptr = default_value_of;

void set_value_of_func(value_of_func func)
{
	if (func != NULL)
		value_of_ptr = func;
	else
		value_of_ptr = default_value_of;
}

/**
 * Return the value of a Constant.
 */
static ir_tarval *computed_value_Const(const ir_node *n)
{
	return get_Const_tarval(n);
}

/**
 * Return the value of a 'sizeof', 'alignof' or 'offsetof' SymConst.
 */
static ir_tarval *computed_value_SymConst(const ir_node *n)
{
	ir_type   *type;
	ir_entity *ent;

	switch (get_SymConst_kind(n)) {
	case symconst_type_size:
		type = get_SymConst_type(n);
		if (get_type_state(type) == layout_fixed)
			return new_tarval_from_long(get_type_size_bytes(type), get_irn_mode(n));
		break;
	case symconst_type_align:
		type = get_SymConst_type(n);
		if (get_type_state(type) == layout_fixed)
			return new_tarval_from_long(get_type_alignment_bytes(type), get_irn_mode(n));
		break;
	case symconst_ofs_ent:
		ent  = get_SymConst_entity(n);
		type = get_entity_owner(ent);
		if (get_type_state(type) == layout_fixed)
			return new_tarval_from_long(get_entity_offset(ent), get_irn_mode(n));
		break;
	default:
		break;
	}
	return tarval_bad;
}

/**
 * Return the value of an Add.
 */
static ir_tarval *computed_value_Add(const ir_node *n)
{
	ir_node *a = get_Add_left(n);
	ir_node *b = get_Add_right(n);

	ir_tarval *ta = value_of(a);
	ir_tarval *tb = value_of(b);

	if ((ta != tarval_bad) && (tb != tarval_bad))
		return tarval_add(ta, tb);

	/* x+~x => -1 */
	if ((is_Not(a) && get_Not_op(a) == b)
	    || (is_Not(b) && get_Not_op(b) == a)) {
		return get_mode_all_one(get_irn_mode(n));
	}

	return tarval_bad;
}

/**
 * Return the value of a Sub.
 * Special case: a - a
 */
static ir_tarval *computed_value_Sub(const ir_node *n)
{
	ir_mode   *mode = get_irn_mode(n);
	ir_node   *a    = get_Sub_left(n);
	ir_node   *b    = get_Sub_right(n);
	ir_tarval *ta;
	ir_tarval *tb;

	/* NaN - NaN != 0 */
	if (! mode_is_float(mode)) {
		/* a - a = 0 */
		if (a == b)
			return get_mode_null(mode);
	}

	ta = value_of(a);
	tb = value_of(b);

	if ((ta != tarval_bad) && (tb != tarval_bad))
		return tarval_sub(ta, tb, mode);

	return tarval_bad;
}

/**
 * Return the value of a Carry.
 * Special : a op 0, 0 op b
 */
static ir_tarval *computed_value_Carry(const ir_node *n)
{
	ir_node   *a  = get_binop_left(n);
	ir_node   *b  = get_binop_right(n);
	ir_mode   *m  = get_irn_mode(n);
	ir_tarval *ta = value_of(a);
	ir_tarval *tb = value_of(b);

	if ((ta != tarval_bad) && (tb != tarval_bad)) {
		tarval_add(ta, tb);
		return tarval_carry() ? get_mode_one(m) : get_mode_null(m);
	} else {
		if (tarval_is_null(ta) || tarval_is_null(tb))
			return get_mode_null(m);
	}
	return tarval_bad;
}

/**
 * Return the value of a Borrow.
 * Special : a op 0
 */
static ir_tarval *computed_value_Borrow(const ir_node *n)
{
	ir_node   *a  = get_binop_left(n);
	ir_node   *b  = get_binop_right(n);
	ir_mode   *m  = get_irn_mode(n);
	ir_tarval *ta = value_of(a);
	ir_tarval *tb = value_of(b);

	if ((ta != tarval_bad) && (tb != tarval_bad)) {
		return tarval_cmp(ta, tb) == ir_relation_less ? get_mode_one(m) : get_mode_null(m);
	} else if (tarval_is_null(ta)) {
		return get_mode_null(m);
	}
	return tarval_bad;
}

/**
 * Return the value of an unary Minus.
 */
static ir_tarval *computed_value_Minus(const ir_node *n)
{
	ir_node   *a  = get_Minus_op(n);
	ir_tarval *ta = value_of(a);

	if (ta != tarval_bad)
		return tarval_neg(ta);

	return tarval_bad;
}

/**
 * Return the value of a Mul.
 */
static ir_tarval *computed_value_Mul(const ir_node *n)
{
	ir_node   *a  = get_Mul_left(n);
	ir_node   *b  = get_Mul_right(n);
	ir_tarval *ta = value_of(a);
	ir_tarval *tb = value_of(b);
	ir_mode   *mode;

	mode = get_irn_mode(n);
	if (mode != get_irn_mode(a)) {
		/* n * n = 2n bit multiplication */
		ta = tarval_convert_to(ta, mode);
		tb = tarval_convert_to(tb, mode);
	}

	if (ta != tarval_bad && tb != tarval_bad) {
		return tarval_mul(ta, tb);
	} else {
		/* a * 0 != 0 if a == NaN or a == Inf */
		if (!mode_is_float(mode)) {
			/* a*0 = 0 or 0*b = 0 */
			if (ta == get_mode_null(mode))
				return ta;
			if (tb == get_mode_null(mode))
				return tb;
		}
	}
	return tarval_bad;
}

/**
 * Return the value of an And.
 * Special case: a & 0, 0 & b
 */
static ir_tarval *computed_value_And(const ir_node *n)
{
	ir_node   *a  = get_And_left(n);
	ir_node   *b  = get_And_right(n);
	ir_tarval *ta = value_of(a);
	ir_tarval *tb = value_of(b);

	if ((ta != tarval_bad) && (tb != tarval_bad)) {
		return tarval_and (ta, tb);
	}

	if (tarval_is_null(ta)) return ta;
	if (tarval_is_null(tb)) return tb;

	/* x&~x => 0 */
	if ((is_Not(a) && get_Not_op(a) == b)
	    || (is_Not(b) && get_Not_op(b) == a)) {
		return get_mode_null(get_irn_mode(n));
	}

	return tarval_bad;
}

/**
 * Return the value of an Or.
 * Special case: a | 1...1, 1...1 | b
 */
static ir_tarval *computed_value_Or(const ir_node *n)
{
	ir_node   *a  = get_Or_left(n);
	ir_node   *b  = get_Or_right(n);
	ir_tarval *ta = value_of(a);
	ir_tarval *tb = value_of(b);

	if ((ta != tarval_bad) && (tb != tarval_bad)) {
		return tarval_or (ta, tb);
	}

	if (tarval_is_all_one(ta)) return ta;
	if (tarval_is_all_one(tb)) return tb;

	/* x|~x => -1 */
	if ((is_Not(a) && get_Not_op(a) == b)
	    || (is_Not(b) && get_Not_op(b) == a)) {
		return get_mode_all_one(get_irn_mode(n));
	}
	return tarval_bad;
}

/**
 * Return the value of an Eor.
 */
static ir_tarval *computed_value_Eor(const ir_node *n)
{
	ir_node *a = get_Eor_left(n);
	ir_node *b = get_Eor_right(n);

	ir_tarval *ta, *tb;

	if (a == b)
		return get_mode_null(get_irn_mode(n));
	/* x^~x => -1 */
	if ((is_Not(a) && get_Not_op(a) == b)
	    || (is_Not(b) && get_Not_op(b) == a)) {
		return get_mode_all_one(get_irn_mode(n));
	}

	ta = value_of(a);
	tb = value_of(b);

	if ((ta != tarval_bad) && (tb != tarval_bad)) {
		return tarval_eor(ta, tb);
	}
	return tarval_bad;
}

/**
 * Return the value of a Not.
 */
static ir_tarval *computed_value_Not(const ir_node *n)
{
	ir_node   *a  = get_Not_op(n);
	ir_tarval *ta = value_of(a);

	if (ta != tarval_bad)
		return tarval_not(ta);

	return tarval_bad;
}

/**
 * Tests whether a shift shifts more bits than available in the mode
 */
static bool is_oversize_shift(const ir_node *n)
{
	ir_node   *count = get_binop_right(n);
	ir_mode   *mode  = get_irn_mode(n);
	ir_tarval *tv    = value_of(count);
	long       modulo_shift;
	long       shiftval;
	if (tv == tarval_bad)
		return false;
	if (!tarval_is_long(tv))
		return false;
	shiftval     = get_tarval_long(tv);
	modulo_shift = get_mode_modulo_shift(mode);
	if (shiftval < 0 || (modulo_shift > 0 && shiftval >= modulo_shift))
		return false;

	return shiftval >= (long)get_mode_size_bits(mode);
}

/**
 * Return the value of a Shl.
 */
static ir_tarval *computed_value_Shl(const ir_node *n)
{
	ir_node *a = get_Shl_left(n);
	ir_node *b = get_Shl_right(n);

	ir_tarval *ta = value_of(a);
	ir_tarval *tb = value_of(b);

	if ((ta != tarval_bad) && (tb != tarval_bad)) {
		return tarval_shl(ta, tb);
	}

	if (is_oversize_shift(n))
		return get_mode_null(get_irn_mode(n));

	return tarval_bad;
}

/**
 * Return the value of a Shr.
 */
static ir_tarval *computed_value_Shr(const ir_node *n)
{
	ir_node *a = get_Shr_left(n);
	ir_node *b = get_Shr_right(n);

	ir_tarval *ta = value_of(a);
	ir_tarval *tb = value_of(b);

	if ((ta != tarval_bad) && (tb != tarval_bad)) {
		return tarval_shr(ta, tb);
	}
	if (is_oversize_shift(n))
		return get_mode_null(get_irn_mode(n));

	return tarval_bad;
}

/**
 * Return the value of a Shrs.
 */
static ir_tarval *computed_value_Shrs(const ir_node *n)
{
	ir_node *a = get_Shrs_left(n);
	ir_node *b = get_Shrs_right(n);

	ir_tarval *ta = value_of(a);
	ir_tarval *tb = value_of(b);

	if ((ta != tarval_bad) && (tb != tarval_bad)) {
		return tarval_shrs(ta, tb);
	}
	return tarval_bad;
}

/**
 * Return the value of a Rotl.
 */
static ir_tarval *computed_value_Rotl(const ir_node *n)
{
	ir_node *a = get_Rotl_left(n);
	ir_node *b = get_Rotl_right(n);

	ir_tarval *ta = value_of(a);
	ir_tarval *tb = value_of(b);

	if ((ta != tarval_bad) && (tb != tarval_bad)) {
		return tarval_rotl(ta, tb);
	}
	return tarval_bad;
}

bool ir_zero_when_converted(const ir_node *node, ir_mode *dest_mode)
{
	ir_mode *mode = get_irn_mode(node);
	if (get_mode_arithmetic(mode) != irma_twos_complement
	    || get_mode_arithmetic(dest_mode) != irma_twos_complement)
	    return false;

	if (is_Shl(node)) {
		ir_node *count = get_Shl_right(node);
		if (is_Const(count)) {
			ir_tarval *tv = get_Const_tarval(count);
			if (tarval_is_long(tv)) {
				long shiftval = get_tarval_long(tv);
				long destbits = get_mode_size_bits(dest_mode);
				if (shiftval >= destbits
				    && shiftval < (long)get_mode_modulo_shift(mode))
					return true;
			}
		}
	}
	if (is_And(node)) {
		ir_node *right = get_And_right(node);
		if (is_Const(right)) {
			ir_tarval *tv     = get_Const_tarval(right);
			ir_tarval *conved = tarval_convert_to(tv, dest_mode);
			return tarval_is_null(conved);
		}
	}
	return false;
}

/**
 * Return the value of a Conv.
 */
static ir_tarval *computed_value_Conv(const ir_node *n)
{
	ir_node   *a    = get_Conv_op(n);
	ir_tarval *ta   = value_of(a);
	ir_mode   *mode = get_irn_mode(n);

	if (ta != tarval_bad)
		return tarval_convert_to(ta, get_irn_mode(n));

	if (ir_zero_when_converted(a, mode))
		return get_mode_null(mode);

	return tarval_bad;
}

/**
 * Calculate the value of a Mux: can be evaluated, if the
 * sel and the right input are known.
 */
static ir_tarval *computed_value_Mux(const ir_node *n)
{
	ir_node *sel = get_Mux_sel(n);
	ir_tarval *ts = value_of(sel);

	if (ts == get_tarval_b_true()) {
		ir_node *v = get_Mux_true(n);
		return value_of(v);
	}
	else if (ts == get_tarval_b_false()) {
		ir_node *v = get_Mux_false(n);
		return value_of(v);
	}
	return tarval_bad;
}

/**
 * Calculate the value of a Confirm: can be evaluated,
 * if it has the form Confirm(x, '=', Const).
 */
static ir_tarval *computed_value_Confirm(const ir_node *n)
{
	if (get_Confirm_relation(n) == ir_relation_equal) {
		ir_tarval *tv = value_of(get_Confirm_bound(n));
		if (tv != tarval_bad)
			return tv;
	}
	return value_of(get_Confirm_value(n));
}

/**
 * gives a (conservative) estimation of possible relation when comparing
 * left+right
 */
ir_relation ir_get_possible_cmp_relations(const ir_node *left,
                                          const ir_node *right)
{
	ir_relation possible = ir_relation_true;
	ir_tarval  *tv_l     = value_of(left);
	ir_tarval  *tv_r     = value_of(right);
	ir_mode    *mode     = get_irn_mode(left);
	ir_tarval  *min      = mode == mode_b ? tarval_b_false : get_mode_min(mode);
	ir_tarval  *max      = mode == mode_b ? tarval_b_true  : get_mode_max(mode);

	/* both values known - evaluate them */
	if ((tv_l != tarval_bad) && (tv_r != tarval_bad)) {
		possible = tarval_cmp(tv_l, tv_r);
		/* we can return now, won't get any better */
		return possible;
	}
	/* a == a is never less or greater (but might be equal or unordered) */
	if (left == right)
		possible &= ~ir_relation_less_greater;
	/* unordered results only happen for float compares */
	if (!mode_is_float(mode))
		possible &= ~ir_relation_unordered;
	/* values can never be less than the least representable number or
	 * greater than the greatest representable number */
	if (tv_l == min)
		possible &= ~ir_relation_greater;
	if (tv_l == max)
		possible &= ~ir_relation_less;
	if (tv_r == max)
		possible &= ~ir_relation_greater;
	if (tv_r == min)
		possible &= ~ir_relation_less;
	/* maybe vrp can tell us more */
	possible &= vrp_cmp(left, right);
	/* Alloc nodes never return null (but throw an exception) */
	if (is_Alloc(left) && tarval_is_null(tv_r))
		possible &= ~ir_relation_equal;
	/* stuff known through confirm nodes */
	if (is_Confirm(left) && get_Confirm_bound(left) == right) {
		possible &= get_Confirm_relation(left);
	}
	if (is_Confirm(right) && get_Confirm_bound(right) == left) {
		ir_relation relation = get_Confirm_relation(right);
		relation = get_inversed_relation(relation);
		possible &= relation;
	}

	return possible;
}

static ir_tarval *compute_cmp(const ir_node *cmp)
{
	ir_node    *left     = get_Cmp_left(cmp);
	ir_node    *right    = get_Cmp_right(cmp);
	ir_relation possible = ir_get_possible_cmp_relations(left, right);
	ir_relation relation = get_Cmp_relation(cmp);

	/* if none of the requested relations is possible, return false */
	if ((possible & relation) == ir_relation_false)
		return tarval_b_false;
	/* if possible relations are a subset of the requested ones return true */
	if ((possible & ~relation) == ir_relation_false)
		return tarval_b_true;

	return computed_value_Cmp_Confirm(cmp, left, right, relation);
}

/**
 * some people want to call compute_cmp directly, in this case we have to
 * test the constant folding flag again
 */
static ir_tarval *compute_cmp_ext(const ir_node *cmp)
{
	if (!get_opt_constant_folding())
		return tarval_bad;
	return compute_cmp(cmp);
}

/**
 * Return the value of a Cmp.
 *
 * The basic idea here is to determine which relations are possible and which
 * one are definitely impossible.
 */
static ir_tarval *computed_value_Cmp(const ir_node *cmp)
{
	/* we can't construct Constb after lowering mode_b nodes */
	if (irg_is_constrained(get_irn_irg(cmp), IR_GRAPH_CONSTRAINT_MODEB_LOWERED))
		return tarval_bad;

	return compute_cmp(cmp);
}

/**
 * Calculate the value of an integer Div.
 * Special case: 0 / b
 */
static ir_tarval *do_computed_value_Div(const ir_node *div)
{
	const ir_node *a    = get_Div_left(div);
	const ir_node *b    = get_Div_right(div);
	const ir_mode *mode = get_Div_resmode(div);
	ir_tarval     *ta   = value_of(a);
	ir_tarval     *tb;
	const ir_node *dummy;

	/* cannot optimize 0 / b = 0 because of NaN */
	if (!mode_is_float(mode)) {
		if (tarval_is_null(ta) && value_not_zero(b, &dummy))
			return ta;  /* 0 / b == 0 if b != 0 */
	}
	tb = value_of(b);
	if (ta != tarval_bad && tb != tarval_bad)
		return tarval_div(ta, tb);
	return tarval_bad;
}

/**
 * Calculate the value of an integer Mod of two nodes.
 * Special case: a % 1
 */
static ir_tarval *do_computed_value_Mod(const ir_node *a, const ir_node *b)
{
	ir_tarval *ta = value_of(a);
	ir_tarval *tb = value_of(b);

	/* Compute a % 1 or c1 % c2 */
	if (tarval_is_one(tb))
		return get_mode_null(get_irn_mode(a));
	if (ta != tarval_bad && tb != tarval_bad)
		return tarval_mod(ta, tb);
	return tarval_bad;
}

/**
 * Return the value of a Proj(Div).
 */
static ir_tarval *computed_value_Proj_Div(const ir_node *n)
{
	long proj_nr = get_Proj_proj(n);
	if (proj_nr != pn_Div_res)
		return tarval_bad;

	return do_computed_value_Div(get_Proj_pred(n));
}

/**
 * Return the value of a Proj(Mod).
 */
static ir_tarval *computed_value_Proj_Mod(const ir_node *n)
{
	long proj_nr = get_Proj_proj(n);

	if (proj_nr == pn_Mod_res) {
		const ir_node *mod = get_Proj_pred(n);
		return do_computed_value_Mod(get_Mod_left(mod), get_Mod_right(mod));
	}
	return tarval_bad;
}

/**
 * Return the value of a Proj.
 */
static ir_tarval *computed_value_Proj(const ir_node *proj)
{
	ir_node *n = get_Proj_pred(proj);

	if (n->op->ops.computed_value_Proj != NULL)
		return n->op->ops.computed_value_Proj(proj);
	return tarval_bad;
}

/**
 * If the parameter n can be computed, return its value, else tarval_bad.
 * Performs constant folding.
 *
 * @param n  The node this should be evaluated
 */
ir_tarval *computed_value(const ir_node *n)
{
	vrp_attr *vrp = vrp_get_info(n);
	if (vrp != NULL && vrp->bits_set == vrp->bits_not_set)
		return vrp->bits_set;

	if (n->op->ops.computed_value)
		return n->op->ops.computed_value(n);
	return tarval_bad;
}

/**
 * Optimize operations that are commutative and have neutral 0,
 * so a op 0 = 0 op a = a.
 */
static ir_node *equivalent_node_neutral_zero(ir_node *n)
{
	ir_node *oldn = n;

	ir_node *a = get_binop_left(n);
	ir_node *b = get_binop_right(n);

	ir_tarval *tv;
	ir_node *on;

	/* After running compute_node there is only one constant predecessor.
	   Find this predecessors value and remember the other node: */
	if ((tv = value_of(a)) != tarval_bad) {
		on = b;
	} else if ((tv = value_of(b)) != tarval_bad) {
		on = a;
	} else
		return n;

	/* If this predecessors constant value is zero, the operation is
	 * unnecessary. Remove it.
	 *
	 * Beware: If n is a Add, the mode of on and n might be different
	 * which happens in this rare construction: NULL + 3.
	 * Then, a Conv would be needed which we cannot include here.
	 */
	if (tarval_is_null(tv) && get_irn_mode(on) == get_irn_mode(n)) {
		n = on;

		DBG_OPT_ALGSIM1(oldn, a, b, n, FS_OPT_NEUTRAL_0);
	}

	return n;
}

/**
 * Eor is commutative and has neutral 0.
 */
static ir_node *equivalent_node_Eor(ir_node *n)
{
	ir_node *oldn = n;
	ir_node *a;
	ir_node *b;

	n = equivalent_node_neutral_zero(n);
	if (n != oldn) return n;

	a = get_Eor_left(n);
	b = get_Eor_right(n);

	if (is_Eor(a) || is_Or_Eor_Add(a)) {
		ir_node *aa = get_binop_left(a);
		ir_node *ab = get_binop_right(a);

		if (aa == b) {
			/* (a ^ b) ^ a -> b */
			n = ab;
			DBG_OPT_ALGSIM1(oldn, a, b, n, FS_OPT_EOR_A_B_A);
			return n;
		} else if (ab == b) {
			/* (a ^ b) ^ b -> a */
			n = aa;
			DBG_OPT_ALGSIM1(oldn, a, b, n, FS_OPT_EOR_A_B_A);
			return n;
		}
	}
	if (is_Eor(b) || is_Or_Eor_Add(b)) {
		ir_node *ba = get_binop_left(b);
		ir_node *bb = get_binop_right(b);

		if (ba == a) {
			/* a ^ (a ^ b) -> b */
			n = bb;
			DBG_OPT_ALGSIM1(oldn, a, b, n, FS_OPT_EOR_A_B_A);
			return n;
		} else if (bb == a) {
			/* a ^ (b ^ a) -> b */
			n = ba;
			DBG_OPT_ALGSIM1(oldn, a, b, n, FS_OPT_EOR_A_B_A);
			return n;
		}
	}
	return n;
}

/*
 * Optimize a - 0 and (a - x) + x (for modes with wrap-around).
 *
 * The second one looks strange, but this construct
 * is used heavily in the LCC sources :-).
 *
 * Beware: The Mode of an Add may be different than the mode of its
 * predecessors, so we could not return a predecessors in all cases.
 */
static ir_node *equivalent_node_Add(ir_node *n)
{
	ir_node *oldn = n;
	ir_node *left, *right;
	ir_mode *mode = get_irn_mode(n);

	n = equivalent_node_neutral_zero(n);
	if (n != oldn)
		return n;

	/* for FP these optimizations are only allowed if fp_strict_algebraic is disabled */
	if (mode_is_float(mode)) {
		ir_graph *irg = get_irn_irg(n);
		if (get_irg_fp_model(irg) & fp_strict_algebraic)
			return n;
	}

	left  = get_Add_left(n);
	right = get_Add_right(n);

	if (is_Sub(left)) {
		if (get_Sub_right(left) == right) {
			/* (a - x) + x */

			n = get_Sub_left(left);
			if (mode == get_irn_mode(n)) {
				DBG_OPT_ALGSIM1(oldn, left, right, n, FS_OPT_ADD_SUB);
				return n;
			}
		}
	}
	if (is_Sub(right)) {
		if (get_Sub_right(right) == left) {
			/* x + (a - x) */

			n = get_Sub_left(right);
			if (mode == get_irn_mode(n)) {
				DBG_OPT_ALGSIM1(oldn, left, right, n, FS_OPT_ADD_SUB);
				return n;
			}
		}
	}
	return n;
}

/**
 * optimize operations that are not commutative but have neutral 0 on left,
 * so a op 0 = a.
 */
static ir_node *equivalent_node_left_zero(ir_node *n)
{
	ir_node *oldn = n;

	ir_node   *a  = get_binop_left(n);
	ir_node   *b  = get_binop_right(n);
	ir_tarval *tb = value_of(b);

	if (tarval_is_null(tb)) {
		n = a;

		DBG_OPT_ALGSIM1(oldn, a, b, n, FS_OPT_NEUTRAL_0);
	}
	return n;
}

/**
 * Optimize a - 0 and (a + x) - x (for modes with wrap-around).
 *
 * The second one looks strange, but this construct
 * is used heavily in the LCC sources :-).
 *
 * Beware: The Mode of a Sub may be different than the mode of its
 * predecessors, so we could not return a predecessors in all cases.
 */
static ir_node *equivalent_node_Sub(ir_node *n)
{
	ir_node   *oldn = n;
	ir_node   *b;
	ir_mode   *mode = get_irn_mode(n);
	ir_tarval *tb;

	/* for FP these optimizations are only allowed if fp_strict_algebraic is disabled */
	if (mode_is_float(mode)) {
		ir_graph *irg = get_irn_irg(n);
		if (get_irg_fp_model(irg) & fp_strict_algebraic)
			return n;
	}

	b  = get_Sub_right(n);
	tb = value_of(b);

	/* Beware: modes might be different */
	if (tarval_is_null(tb)) {
		ir_node *a = get_Sub_left(n);
		if (mode == get_irn_mode(a)) {
			n = a;

			DBG_OPT_ALGSIM1(oldn, a, b, n, FS_OPT_NEUTRAL_0);
		}
	}
	return n;
}


/**
 * Optimize an "self-inverse unary op", i.e. op(op(n)) = n.
 *
 * @todo
 *   -(-a) == a, but might overflow two times.
 *   We handle it anyway here but the better way would be a
 *   flag. This would be needed for Pascal for instance.
 */
static ir_node *equivalent_node_involution(ir_node *n)
{
	ir_node *oldn = n;
	ir_node *pred = get_unop_op(n);
	if (get_irn_op(pred) == get_irn_op(n)) {
		n = get_unop_op(pred);
		DBG_OPT_ALGSIM2(oldn, pred, n, FS_OPT_INVOLUTION);
	}
	return n;
}

/**
 * Optimize a * 1 = 1 * a = a.
 */
static ir_node *equivalent_node_Mul(ir_node *n)
{
	ir_node *oldn = n;
	ir_node *a = get_Mul_left(n);

	/* we can handle here only the n * n = n bit cases */
	if (get_irn_mode(n) == get_irn_mode(a)) {
		ir_node   *b = get_Mul_right(n);
		ir_tarval *tv;

		/*
		 * Mul is commutative and has again an other neutral element.
		 * Constants are place right, so check this case first.
		 */
		tv = value_of(b);
		if (tarval_is_one(tv)) {
			n = a;
			DBG_OPT_ALGSIM1(oldn, a, b, n, FS_OPT_NEUTRAL_1);
		} else {
			tv = value_of(a);
			if (tarval_is_one(tv)) {
				n = b;
				DBG_OPT_ALGSIM1(oldn, a, b, n, FS_OPT_NEUTRAL_1);
			}
		}
	}
	return n;
}

/**
 * Use algebraic simplification a | a = a | 0 = 0 | a = a.
 */
static ir_node *equivalent_node_Or(ir_node *n)
{
	ir_node *oldn = n;

	ir_node   *a = get_Or_left(n);
	ir_node   *b = get_Or_right(n);
	ir_tarval *tv;

	if (a == b) {
		n = a;    /* idempotence */
		DBG_OPT_ALGSIM0(oldn, n, FS_OPT_OR);
		return n;
	}
	/* constants are normalized to right, check this side first */
	tv = value_of(b);
	if (tarval_is_null(tv)) {
		n = a;
		DBG_OPT_ALGSIM1(oldn, a, b, n, FS_OPT_OR);
		return n;
	}
	tv = value_of(a);
	if (tarval_is_null(tv)) {
		n = b;
		DBG_OPT_ALGSIM1(oldn, a, b, n, FS_OPT_OR);
		return n;
	}

	return n;
}

/**
 * Optimize a & 0b1...1 = 0b1...1 & a = a & a = (a|X) & a = a.
 */
static ir_node *equivalent_node_And(ir_node *n)
{
	ir_node *oldn = n;

	ir_node   *a = get_And_left(n);
	ir_node   *b = get_And_right(n);
	ir_tarval *tv;

	if (a == b) {
		n = a;    /* idempotence */
		DBG_OPT_ALGSIM0(oldn, n, FS_OPT_AND);
		return n;
	}
	/* constants are normalized to right, check this side first */
	tv = value_of(b);
	if (tarval_is_all_one(tv)) {
		n = a;
		DBG_OPT_ALGSIM1(oldn, a, b, n, FS_OPT_AND);
		return n;
	}
	if (tv != get_tarval_bad()) {
		ir_mode *mode = get_irn_mode(n);
		if (!mode_is_signed(mode) && is_Conv(a)) {
			ir_node *convop     = get_Conv_op(a);
			ir_mode *convopmode = get_irn_mode(convop);
			if (!mode_is_signed(convopmode)) {
				/* Check Conv(all_one) & Const = all_one */
				ir_tarval *one  = get_mode_all_one(convopmode);
				ir_tarval *conv = tarval_convert_to(one, mode);
				ir_tarval *tand = tarval_and(conv, tv);

				if (tarval_is_all_one(tand)) {
					/* Conv(X) & Const = X */
					n = a;
					DBG_OPT_ALGSIM1(oldn, a, b, n, FS_OPT_AND);
					return n;
				}
			}
		}
	}
	tv = value_of(a);
	if (tarval_is_all_one(tv)) {
		n = b;
		DBG_OPT_ALGSIM1(oldn, a, b, n, FS_OPT_AND);
		return n;
	}
	/* (a|X) & a => a*/
	if ((is_Or(a) || is_Or_Eor_Add(a))
	    && (b == get_binop_left(a) || b == get_binop_right(a))) {
		n = b;
		DBG_OPT_ALGSIM1(oldn, a, b, n, FS_OPT_AND);
		return n;
	}
	/* a & (a|X) => a*/
	if ((is_Or(b) || is_Or_Eor_Add(b))
	    && (a == get_binop_left(b) || a == get_binop_right(b))) {
		n = a;
		DBG_OPT_ALGSIM1(oldn, a, b, n, FS_OPT_AND);
		return n;
	}
	return n;
}

/**
 * Try to remove useless Conv's:
 */
static ir_node *equivalent_node_Conv(ir_node *n)
{
	ir_node *oldn = n;
	ir_node *a = get_Conv_op(n);

	ir_mode *n_mode = get_irn_mode(n);
	ir_mode *a_mode = get_irn_mode(a);

	if (n_mode == a_mode) { /* No Conv necessary */
		n = a;
		DBG_OPT_ALGSIM0(oldn, n, FS_OPT_CONV);
		return n;
	} else if (is_Conv(a)) { /* Conv(Conv(b)) */
		ir_node *b      = get_Conv_op(a);
		ir_mode *b_mode = get_irn_mode(b);

		if (n_mode == b_mode && values_in_mode(b_mode, a_mode)) {
			n = b;
			DBG_OPT_ALGSIM1(oldn, a, b, n, FS_OPT_CONV);
			return n;
		}
	}
	return n;
}

/**
 * - fold Phi-nodes, iff they have only one predecessor except
 *   themselves.
 */
static ir_node *equivalent_node_Phi(ir_node *n)
{
	int i, n_preds;

	ir_node *oldn = n;
	ir_node *first_val = NULL; /* to shutup gcc */

	if (!get_opt_optimize() &&
	    !irg_is_constrained(get_irn_irg(n), IR_GRAPH_CONSTRAINT_CONSTRUCTION))
		return n;

	n_preds = get_Phi_n_preds(n);

	/* Phi of dead Region without predecessors. */
	if (n_preds == 0)
		return n;

	/* Find first non-self-referencing input */
	for (i = 0; i < n_preds; ++i) {
		first_val = get_Phi_pred(n, i);
		/* not self pointer */
		if (first_val != n) {
			/* then found first value. */
			break;
		}
	}

	/* search for rest of inputs, determine if any of these
	are non-self-referencing */
	while (++i < n_preds) {
		ir_node *scnd_val = get_Phi_pred(n, i);
		if (scnd_val != n && scnd_val != first_val) {
			break;
		}
	}

	if (i >= n_preds && !is_Dummy(first_val)) {
		/* Fold, if no multiple distinct non-self-referencing inputs */
		n = first_val;
		DBG_OPT_PHI(oldn, n);
	}
	return n;
}

/**
 * Optimize Proj(Tuple).
 */
static ir_node *equivalent_node_Proj_Tuple(ir_node *proj)
{
	ir_node *oldn  = proj;
	ir_node *tuple = get_Proj_pred(proj);

	/* Remove the Tuple/Proj combination. */
	proj = get_Tuple_pred(tuple, get_Proj_proj(proj));
	DBG_OPT_TUPLE(oldn, tuple, proj);

	return proj;
}

/**
 * Optimize a / 1 = a.
 */
static ir_node *equivalent_node_Proj_Div(ir_node *proj)
{
	ir_node   *oldn = proj;
	ir_node   *div  = get_Proj_pred(proj);
	ir_node   *b    = get_Div_right(div);
	ir_tarval *tb   = value_of(b);

	/* Div is not commutative. */
	if (tarval_is_one(tb)) { /* div(x, 1) == x */
		switch (get_Proj_proj(proj)) {
		case pn_Div_M:
			proj = get_Div_mem(div);
			DBG_OPT_ALGSIM0(oldn, proj, FS_OPT_NEUTRAL_1);
			return proj;

		case pn_Div_res:
			proj = get_Div_left(div);
			DBG_OPT_ALGSIM0(oldn, proj, FS_OPT_NEUTRAL_1);
			return proj;

		default:
			/* we cannot replace the exception Proj's here, this is done in
			   transform_node_Proj_Div() */
			return proj;
		}
	}
	return proj;
}

/**
 * Optimize CopyB(mem, x, x) into a Nop.
 */
static ir_node *equivalent_node_Proj_CopyB(ir_node *proj)
{
	ir_node *oldn  = proj;
	ir_node *copyb = get_Proj_pred(proj);
	ir_node *a     = get_CopyB_dst(copyb);
	ir_node *b     = get_CopyB_src(copyb);

	if (a == b) {
		/* Turn CopyB into a tuple (mem, jmp, bad, bad) */
		switch (get_Proj_proj(proj)) {
		case pn_CopyB_M:
			proj = get_CopyB_mem(copyb);
			DBG_OPT_ALGSIM0(oldn, proj, FS_OPT_NOP);
			break;
		}
	}
	return proj;
}

/**
 * Optimize Bounds(idx, idx, upper) into idx.
 */
static ir_node *equivalent_node_Proj_Bound(ir_node *proj)
{
	ir_node *oldn  = proj;
	ir_node *bound = get_Proj_pred(proj);
	ir_node *idx   = get_Bound_index(bound);
	ir_node *pred  = skip_Proj(idx);
	int ret_tuple  = 0;

	if (idx == get_Bound_lower(bound))
		ret_tuple = 1;
	else if (is_Bound(pred)) {
		/*
		 * idx was Bounds checked previously, it is still valid if
		 * lower <= pred_lower && pred_upper <= upper.
		 */
		ir_node *lower = get_Bound_lower(bound);
		ir_node *upper = get_Bound_upper(bound);
		if (get_Bound_lower(pred) == lower &&
			get_Bound_upper(pred) == upper) {
			/*
			 * One could expect that we simply return the previous
			 * Bound here. However, this would be wrong, as we could
			 * add an exception Proj to a new location then.
			 * So, we must turn in into a tuple.
			 */
			ret_tuple = 1;
		}
	}
	if (ret_tuple) {
		/* Turn Bound into a tuple (mem, jmp, bad, idx) */
		switch (get_Proj_proj(proj)) {
		case pn_Bound_M:
			DBG_OPT_EXC_REM(proj);
			proj = get_Bound_mem(bound);
			break;
		case pn_Bound_res:
			proj = idx;
			DBG_OPT_ALGSIM0(oldn, proj, FS_OPT_NOP);
			break;
		default:
			/* cannot optimize pn_Bound_X_regular, handled in transform ... */
			break;
		}
	}
	return proj;
}

/**
 * Does all optimizations on nodes that must be done on its Projs
 * because of creating new nodes.
 */
static ir_node *equivalent_node_Proj(ir_node *proj)
{
	ir_node *n = get_Proj_pred(proj);
	if (n->op->ops.equivalent_node_Proj)
		return n->op->ops.equivalent_node_Proj(proj);
	return proj;
}

/**
 * Remove Id's.
 */
static ir_node *equivalent_node_Id(ir_node *n)
{
	ir_node *oldn = n;

	do {
		n = get_Id_pred(n);
	} while (is_Id(n));

	DBG_OPT_ID(oldn, n);
	return n;
}

/**
 * Optimize a Mux.
 */
static ir_node *equivalent_node_Mux(ir_node *n)
{
	ir_node   *oldn = n, *sel = get_Mux_sel(n);
	ir_node   *n_t, *n_f;
	ir_tarval *ts = value_of(sel);

	if (ts == tarval_bad && is_Cmp(sel)) {
		/* try again with a direct call to compute_cmp, as we don't care
		 * about the MODEB_LOWERED flag here */
		ts = compute_cmp_ext(sel);
	}

	/* Mux(true, f, t) == t */
	if (ts == tarval_b_true) {
		n = get_Mux_true(n);
		DBG_OPT_ALGSIM0(oldn, n, FS_OPT_MUX_C);
		return n;
	}
	/* Mux(false, f, t) == f */
	if (ts == tarval_b_false) {
		n = get_Mux_false(n);
		DBG_OPT_ALGSIM0(oldn, n, FS_OPT_MUX_C);
		return n;
	}
	n_t = get_Mux_true(n);
	n_f = get_Mux_false(n);

	/* Mux(v, x, T) == x */
	if (is_Unknown(n_f)) {
		n = n_t;
		DBG_OPT_ALGSIM0(oldn, n, FS_OPT_MUX_EQ);
		return n;
	}
	/* Mux(v, T, x) == x */
	if (is_Unknown(n_t)) {
		n = n_f;
		DBG_OPT_ALGSIM0(oldn, n, FS_OPT_MUX_EQ);
		return n;
	}

	/* Mux(v, x, x) == x */
	if (n_t == n_f) {
		n = n_t;
		DBG_OPT_ALGSIM0(oldn, n, FS_OPT_MUX_EQ);
		return n;
	}
	if (is_Cmp(sel) && !mode_honor_signed_zeros(get_irn_mode(n))) {
		ir_relation relation = get_Cmp_relation(sel);
		ir_node    *f        = get_Mux_false(n);
		ir_node    *t        = get_Mux_true(n);

		/*
		 * Note further that these optimization work even for floating point
		 * with NaN's because -NaN == NaN.
		 * However, if +0 and -0 is handled differently, we cannot use the first one.
		 */
		ir_node *const cmp_l = get_Cmp_left(sel);
		ir_node *const cmp_r = get_Cmp_right(sel);

		switch (relation) {
		case ir_relation_equal:
			if ((cmp_l == t && cmp_r == f) || /* Mux(t == f, t, f) -> f */
					(cmp_l == f && cmp_r == t)) { /* Mux(f == t, t, f) -> f */
				n = f;
				DBG_OPT_ALGSIM0(oldn, n, FS_OPT_MUX_TRANSFORM);
				return n;
			}
			break;

		case ir_relation_less_greater:
		case ir_relation_unordered_less_greater:
			if ((cmp_l == t && cmp_r == f) || /* Mux(t != f, t, f) -> t */
					(cmp_l == f && cmp_r == t)) { /* Mux(f != t, t, f) -> t */
				n = t;
				DBG_OPT_ALGSIM0(oldn, n, FS_OPT_MUX_TRANSFORM);
				return n;
			}
			break;
		default:
			break;
		}

		/*
		 * Note: normalization puts the constant on the right side,
		 * so we check only one case.
		 */
		if (cmp_l == t && tarval_is_null(value_of(cmp_r))) {
			/* Mux(t CMP 0, X, t) */
			if (is_Minus(f) && get_Minus_op(f) == t) {
				/* Mux(t CMP 0, -t, t) */
				if (relation == ir_relation_equal) {
					/* Mux(t == 0, -t, t)  ==>  -t */
					n = f;
					DBG_OPT_ALGSIM0(oldn, n, FS_OPT_MUX_TRANSFORM);
				} else if (relation == ir_relation_less_greater || relation == ir_relation_unordered_less_greater) {
					/* Mux(t != 0, -t, t)  ==> t */
					n = t;
					DBG_OPT_ALGSIM0(oldn, n, FS_OPT_MUX_TRANSFORM);
				}
			}
		}
	}

	return n;
}

/**
 * Remove Confirm nodes if setting is on.
 * Replace Confirms(x, '=', Constlike) by Constlike.
 */
static ir_node *equivalent_node_Confirm(ir_node *n)
{
	ir_node    *pred     = get_Confirm_value(n);
	ir_relation relation = get_Confirm_relation(n);

	while (is_Confirm(pred) && relation == get_Confirm_relation(pred)) {
		/*
		 * rare case: two identical Confirms one after another,
		 * replace the second one with the first.
		 */
		n    = pred;
		pred = get_Confirm_value(n);
	}
	return n;
}

/**
 * equivalent_node() returns a node equivalent to input n. It skips all nodes that
 * perform no actual computation, as, e.g., the Id nodes.  It does not create
 * new nodes.  It is therefore safe to free n if the node returned is not n.
 * If a node returns a Tuple we can not just skip it.  If the size of the
 * in array fits, we transform n into a tuple (e.g., Div).
 */
ir_node *equivalent_node(ir_node *n)
{
	if (n->op->ops.equivalent_node)
		return n->op->ops.equivalent_node(n);
	return n;
}

/**
 * Returns non-zero if a node is a Phi node
 * with all predecessors constant.
 */
static int is_const_Phi(ir_node *n)
{
	int i;

	if (! is_Phi(n) || get_irn_arity(n) == 0)
		return 0;
	for (i = get_irn_arity(n) - 1; i >= 0; --i) {
		if (! is_Const(get_irn_n(n, i)))
			return 0;
	}
	return 1;
}

typedef ir_tarval *(*tarval_sub_type)(ir_tarval *a, ir_tarval *b, ir_mode *mode);
typedef ir_tarval *(*tarval_binop_type)(ir_tarval *a, ir_tarval *b);

/**
 * in reality eval_func should be tarval (*eval_func)() but incomplete
 * declarations are bad style and generate noisy warnings
 */
typedef void (*eval_func)(void);

/**
 * Wrapper for the tarval binop evaluation, tarval_sub has one more parameter.
 */
static ir_tarval *do_eval(eval_func eval, ir_tarval *a, ir_tarval *b, ir_mode *mode)
{
	if (eval == (eval_func) tarval_sub) {
		tarval_sub_type func = (tarval_sub_type)eval;

		return func(a, b, mode);
	} else {
		tarval_binop_type func = (tarval_binop_type)eval;

		return func(a, b);
	}
}

/**
 * Apply an evaluator on a binop with a constant operators (and one Phi).
 *
 * @param phi    the Phi node
 * @param other  the other operand
 * @param eval   an evaluator function
 * @param mode   the mode of the result, may be different from the mode of the Phi!
 * @param left   if non-zero, other is the left operand, else the right
 *
 * @return a new Phi node if the conversion was successful, NULL else
 */
static ir_node *apply_binop_on_phi(ir_node *phi, ir_tarval *other, eval_func eval, ir_mode *mode, int left)
{
	int         n   = get_irn_arity(phi);
	ir_tarval **tvs = ALLOCAN(ir_tarval*, n);
	if (left) {
		for (int i = 0; i < n; ++i) {
			ir_node   *pred = get_irn_n(phi, i);
			ir_tarval *tv   = get_Const_tarval(pred);
			tv = do_eval(eval, other, tv, mode);

			if (tv == tarval_bad) {
				/* folding failed, bad */
				return NULL;
			}
			tvs[i] = tv;
		}
	} else {
		for (int i = 0; i < n; ++i) {
			ir_node   *pred = get_irn_n(phi, i);
			ir_tarval *tv   = get_Const_tarval(pred);
			tv = do_eval(eval, tv, other, mode);

			if (tv == tarval_bad) {
				/* folding failed, bad */
				return 0;
			}
			tvs[i] = tv;
		}
	}
	ir_graph *irg = get_irn_irg(phi);
	ir_node **res = ALLOCAN(ir_node*, n);
	for (int i = 0; i < n; ++i) {
		res[i] = new_r_Const(irg, tvs[i]);
	}
	ir_node *block = get_nodes_block(phi);
	return new_r_Phi(block, n, res, mode);
}

/**
 * Apply an evaluator on a binop with two constant Phi.
 *
 * @param a      the left Phi node
 * @param b      the right Phi node
 * @param eval   an evaluator function
 * @param mode   the mode of the result, may be different from the mode of the Phi!
 *
 * @return a new Phi node if the conversion was successful, NULL else
 */
static ir_node *apply_binop_on_2_phis(ir_node *a, ir_node *b, eval_func eval, ir_mode *mode)
{
	if (get_nodes_block(a) != get_nodes_block(b))
		return NULL;

	int         n   = get_irn_arity(a);
	ir_tarval **tvs = ALLOCAN(ir_tarval*, n);
	for (int i = 0; i < n; ++i) {
		ir_node   *pred_a = get_irn_n(a, i);
		ir_tarval *tv_l   = get_Const_tarval(pred_a);
		ir_node   *pred_b = get_irn_n(b, i);
		ir_tarval *tv_r   = get_Const_tarval(pred_b);
		ir_tarval *tv     = do_eval(eval, tv_l, tv_r, mode);

		if (tv == tarval_bad) {
			/* folding failed, bad */
			return NULL;
		}
		tvs[i] = tv;
	}
	ir_graph *irg = get_irn_irg(a);
	ir_node **res = ALLOCAN(ir_node*, n);
	for (int i = 0; i < n; ++i) {
		res[i] = new_r_Const(irg, tvs[i]);
	}
	ir_node *block = get_nodes_block(a);
	return new_r_Phi(block, n, res, mode);
}

/**
 * Apply an evaluator on a unop with a constant operator (a Phi).
 *
 * @param phi    the Phi node
 * @param eval   an evaluator function
 *
 * @return a new Phi node if the conversion was successful, NULL else
 */
static ir_node *apply_unop_on_phi(ir_node *phi, ir_tarval *(*eval)(ir_tarval *))
{
	int         n   = get_irn_arity(phi);
	ir_tarval **tvs = ALLOCAN(ir_tarval*, n);
	for (int i = 0; i < n; ++i) {
		ir_node   *pred = get_irn_n(phi, i);
		ir_tarval *tv   = get_Const_tarval(pred);
		tv = eval(tv);

		if (tv == tarval_bad) {
			/* folding failed, bad */
			return 0;
		}
		tvs[i] = tv;
	}
	ir_graph *irg  = get_irn_irg(phi);
	ir_node **res  = ALLOCAN(ir_node*, n);
	for (int i = 0; i < n; ++i) {
		res[i] = new_r_Const(irg, tvs[i]);
	}
	ir_node *block = get_nodes_block(phi);
	ir_mode *mode  = get_irn_mode(phi);
	return new_r_Phi(block, n, res, mode);
}

/**
 * Apply a conversion on a constant operator (a Phi).
 *
 * @param phi    the Phi node
 *
 * @return a new Phi node if the conversion was successful, NULL else
 */
static ir_node *apply_conv_on_phi(ir_node *phi, ir_mode *mode)
{
	int         n   = get_irn_arity(phi);
	ir_tarval **tvs = ALLOCAN(ir_tarval*, n);
	for (int i = 0; i < n; ++i) {
		ir_node   *pred = get_irn_n(phi, i);
		ir_tarval *tv   = get_Const_tarval(pred);
		tv = tarval_convert_to(tv, mode);

		if (tv == tarval_bad) {
			/* folding failed, bad */
			return 0;
		}
		tvs[i] = tv;
	}
	ir_graph *irg = get_irn_irg(phi);
	ir_node **res = ALLOCAN(ir_node*, n);
	for (int i = 0; i < n; ++i) {
		res[i] = new_r_Const(irg, tvs[i]);
	}
	ir_node *block = get_nodes_block(phi);
	return new_r_Phi(block, n, res, mode);
}

/**
 * Transform AddP(P, ConvIs(Iu)), AddP(P, ConvIu(Is)) and
 * SubP(P, ConvIs(Iu)), SubP(P, ConvIu(Is)).
 * If possible, remove the Conv's.
 */
static ir_node *transform_node_AddSub(ir_node *n)
{
	ir_mode *mode = get_irn_mode(n);

	if (mode_is_reference(mode)) {
		ir_node *left     = get_binop_left(n);
		ir_node *right    = get_binop_right(n);
		unsigned ref_bits = get_mode_size_bits(mode);

		if (is_Conv(left)) {
			ir_mode *lmode = get_irn_mode(left);
			unsigned bits = get_mode_size_bits(lmode);

			if (ref_bits == bits &&
			    mode_is_int(lmode) &&
			    get_mode_arithmetic(lmode) == irma_twos_complement) {
				ir_node *pre      = get_Conv_op(left);
				ir_mode *pre_mode = get_irn_mode(pre);

				if (mode_is_int(pre_mode) &&
				    get_mode_size_bits(pre_mode) == bits &&
				    get_mode_arithmetic(pre_mode) == irma_twos_complement) {
					/* ok, this conv just changes to sign, moreover the calculation
					 * is done with same number of bits as our address mode, so
					 * we can ignore the conv as address calculation can be viewed
					 * as either signed or unsigned
					 */
					set_binop_left(n, pre);
				}
			}
		}

		if (is_Conv(right)) {
			ir_mode *rmode = get_irn_mode(right);
			unsigned bits = get_mode_size_bits(rmode);

			if (ref_bits == bits &&
			    mode_is_int(rmode) &&
			    get_mode_arithmetic(rmode) == irma_twos_complement) {
				ir_node *pre      = get_Conv_op(right);
				ir_mode *pre_mode = get_irn_mode(pre);

				if (mode_is_int(pre_mode) &&
				    get_mode_size_bits(pre_mode) == bits &&
				    get_mode_arithmetic(pre_mode) == irma_twos_complement) {
					/* ok, this conv just changes to sign, moreover the calculation
					 * is done with same number of bits as our address mode, so
					 * we can ignore the conv as address calculation can be viewed
					 * as either signed or unsigned
					 */
					set_binop_right(n, pre);
				}
			}
		}

		/* let address arithmetic use unsigned modes */
		if (is_Const(right)) {
			ir_mode *rmode = get_irn_mode(right);

			if (mode_is_signed(rmode) && get_mode_arithmetic(rmode) == irma_twos_complement) {
				/* convert a AddP(P, *s) into AddP(P, *u) */
				ir_mode *nm = get_reference_mode_unsigned_eq(mode);

				ir_node *pre = new_r_Conv(get_nodes_block(n), right, nm);
				set_binop_right(n, pre);
			}
		}
	}

	return n;
}

#define HANDLE_BINOP_PHI(eval, a, b, c, mode)                     \
  do {                                                            \
  c = NULL;                                                       \
  if (is_Const(b) && is_const_Phi(a)) {                           \
    /* check for Op(Phi, Const) */                                \
    c = apply_binop_on_phi(a, get_Const_tarval(b), eval, mode, 0);\
  }                                                               \
  else if (is_Const(a) && is_const_Phi(b)) {                      \
    /* check for Op(Const, Phi) */                                \
    c = apply_binop_on_phi(b, get_Const_tarval(a), eval, mode, 1);\
  }                                                               \
  else if (is_const_Phi(a) && is_const_Phi(b)) {                  \
    /* check for Op(Phi, Phi) */                                  \
    c = apply_binop_on_2_phis(a, b, eval, mode);                  \
  }                                                               \
  if (c) {                                                        \
    DBG_OPT_ALGSIM0(oldn, c, FS_OPT_CONST_PHI);                   \
    return c;                                                     \
  }                                                               \
  } while(0)

#define HANDLE_UNOP_PHI(eval, a, c)               \
  do {                                            \
  c = NULL;                                       \
  if (is_const_Phi(a)) {                          \
    /* check for Op(Phi) */                       \
    c = apply_unop_on_phi(a, eval);               \
    if (c) {                                      \
      DBG_OPT_ALGSIM0(oldn, c, FS_OPT_CONST_PHI); \
      return c;                                   \
    }                                             \
  }                                               \
  } while(0)

/**
 * Create a 0 constant of given mode.
 */
static ir_node *create_zero_const(ir_graph *irg, ir_mode *mode)
{
	ir_tarval *tv   = get_mode_null(mode);
	ir_node   *cnst = new_r_Const(irg, tv);

	return cnst;
}

static bool is_shiftop(const ir_node *n)
{
	return is_Shl(n) || is_Shr(n) || is_Shrs(n) || is_Rotl(n);
}

/* the order of the values is important! */
typedef enum const_class {
	const_const = 0,
	const_like  = 1,
	const_other = 2
} const_class;

static const_class classify_const(const ir_node* n)
{
	if (is_Const(n))         return const_const;
	if (is_irn_constlike(n)) return const_like;
	return const_other;
}

/**
 * Determines whether r is more constlike or has a larger index (in that order)
 * than l.
 */
static bool operands_are_normalized(const ir_node *l, const ir_node *r)
{
	const const_class l_order = classify_const(l);
	const const_class r_order = classify_const(r);
	return
		l_order > r_order ||
		(l_order == r_order && get_irn_idx(l) <= get_irn_idx(r));
}

static bool is_cmp_unequal(const ir_node *node)
{
	ir_relation relation = get_Cmp_relation(node);
	ir_node    *left     = get_Cmp_left(node);
	ir_node    *right    = get_Cmp_right(node);
	ir_mode    *mode     = get_irn_mode(left);

	if (relation == ir_relation_less_greater)
		return true;

	if (!mode_is_signed(mode) && is_Const(right) && is_Const_null(right))
		return relation == ir_relation_greater;
	return false;
}

/**
 * returns true for Cmp(x == 0) or Cmp(x != 0)
 */
static bool is_cmp_equality_zero(const ir_node *node)
{
	ir_relation relation;
	ir_node    *right    = get_Cmp_right(node);

	if (!is_Const(right) || !is_Const_null(right))
		return false;
	relation = get_Cmp_relation(node);
	return relation == ir_relation_equal
		|| relation == ir_relation_less_greater
		|| (!mode_is_signed(get_irn_mode(right))
		    && relation == ir_relation_greater);
}

/**
 * Optimize a Or(And(Or(And(v,c4),c3),c2),c1) pattern if possible.
 * Such pattern may arise in bitfield stores.
 *
 * value  c4                  value      c4 & c2
 *    AND     c3                    AND           c1 | c3
 *        OR     c2      ===>               OR
 *           AND    c1
 *               OR
 *
 *
 * value  c2                 value  c1
 *     AND   c1    ===>           OR     if (c1 | c2) == 0x111..11
 *        OR
 */
static ir_node *transform_node_Or_bf_store(ir_node *irn_or)
{
	ir_node *irn_and, *c1;
	ir_node *or_l, *c2;
	ir_node *and_l, *c3;
	ir_node *value, *c4;
	ir_node *new_and, *new_const, *block;
	ir_mode *mode = get_irn_mode(irn_or);

	ir_tarval *tv1, *tv2, *tv3, *tv4, *tv;

	for (;;) {
		ir_graph *irg;
		irn_and = get_binop_left(irn_or);
		c1      = get_binop_right(irn_or);
		if (!is_Const(c1) || !is_And(irn_and))
			return irn_or;

		or_l = get_binop_left(irn_and);
		c2   = get_binop_right(irn_and);
		if (!is_Const(c2))
			return irn_or;

		tv1 = get_Const_tarval(c1);
		tv2 = get_Const_tarval(c2);

		tv = tarval_or(tv1, tv2);
		if (tarval_is_all_one(tv)) {
			/* the AND does NOT clear a bit with isn't set by the OR */
			set_binop_left(irn_or, or_l);
			set_binop_right(irn_or, c1);

			/* check for more */
			continue;
		}

		if (!is_Or(or_l) && !is_Or_Eor_Add(or_l))
			return irn_or;

		and_l = get_binop_left(or_l);
		c3    = get_binop_right(or_l);
		if (!is_Const(c3) || !is_And(and_l))
			return irn_or;

		value = get_binop_left(and_l);
		c4    = get_binop_right(and_l);
		if (!is_Const(c4))
			return irn_or;

		/* ok, found the pattern, check for conditions */
		assert(mode == get_irn_mode(irn_and));
		assert(mode == get_irn_mode(or_l));
		assert(mode == get_irn_mode(and_l));

		tv3 = get_Const_tarval(c3);
		tv4 = get_Const_tarval(c4);

		tv = tarval_or(tv4, tv2);
		if (!tarval_is_all_one(tv)) {
			/* have at least one 0 at the same bit position */
			return irn_or;
		}

		if (tv3 != tarval_andnot(tv3, tv4)) {
			/* bit in the or_mask is outside the and_mask */
			return irn_or;
		}

		if (tv1 != tarval_andnot(tv1, tv2)) {
			/* bit in the or_mask is outside the and_mask */
			return irn_or;
		}

		/* ok, all conditions met */
		block = get_nodes_block(irn_or);
		irg   = get_irn_irg(block);

		new_and = new_r_And(block, value, new_r_Const(irg, tarval_and(tv4, tv2)), mode);

		new_const = new_r_Const(irg, tarval_or(tv3, tv1));

		set_binop_left(irn_or, new_and);
		set_binop_right(irn_or, new_const);

		/* check for more */
	}
}

/**
 * Optimize an Or(shl(x, c), shr(x, bits - c)) into a Rotl
 */
static ir_node *transform_node_Or_Rotl(ir_node *irn_or)
{
	ir_mode *mode = get_irn_mode(irn_or);
	ir_node *shl, *shr, *block;
	ir_node *irn, *x, *c1, *c2, *n;
	ir_tarval *tv1, *tv2;

	/* some backends can't handle rotl */
	if (!be_get_backend_param()->support_rotl)
		return irn_or;

	if (! mode_is_int(mode))
		return irn_or;

	shl = get_binop_left(irn_or);
	shr = get_binop_right(irn_or);

	if (is_Shr(shl)) {
		if (!is_Shl(shr))
			return irn_or;

		irn = shl;
		shl = shr;
		shr = irn;
	} else if (!is_Shl(shl)) {
		return irn_or;
	} else if (!is_Shr(shr)) {
		return irn_or;
	}
	x = get_Shl_left(shl);
	if (x != get_Shr_left(shr))
		return irn_or;

	c1 = get_Shl_right(shl);
	c2 = get_Shr_right(shr);
	if (is_Const(c1) && is_Const(c2)) {
		tv1 = get_Const_tarval(c1);
		if (! tarval_is_long(tv1))
			return irn_or;

		tv2 = get_Const_tarval(c2);
		if (! tarval_is_long(tv2))
			return irn_or;

		if (get_tarval_long(tv1) + get_tarval_long(tv2)
				!= (int) get_mode_size_bits(mode))
			return irn_or;

		/* yet, condition met */
		block = get_nodes_block(irn_or);

		n = new_r_Rotl(block, x, c1, mode);

		DBG_OPT_ALGSIM1(irn_or, shl, shr, n, FS_OPT_OR_SHFT_TO_ROTL);
		return n;
	}

	/* Note: the obvious rot formulation (a << x) | (a >> (32-x)) gets
	 * transformed to (a << x) | (a >> -x) by transform_node_shift_modulo() */
	if (!ir_is_negated_value(c1, c2)) {
		return irn_or;
	}

	/* yet, condition met */
	block = get_nodes_block(irn_or);
	n = new_r_Rotl(block, x, c1, mode);
	DBG_OPT_ALGSIM0(irn_or, n, FS_OPT_OR_SHFT_TO_ROTL);
	return n;
}

/**
 * Prototype of a recursive transform function
 * for bitwise distributive transformations.
 */
typedef ir_node* (*recursive_transform)(ir_node *n);

/**
 * makes use of distributive laws for and, or, eor
 *     and(a OP c, b OP c) -> and(a, b) OP c
 * note, might return a different op than n
 */
static ir_node *transform_bitwise_distributive(ir_node *n,
                                               recursive_transform trans_func)
{
	ir_node *oldn    = n;
	ir_node *a       = get_binop_left(n);
	ir_node *b       = get_binop_right(n);
	ir_op   *op      = get_irn_op(a);
	ir_op   *op_root = get_irn_op(n);

	if (op != get_irn_op(b))
		return n;

	/* and(conv(a), conv(b)) -> conv(and(a,b)) */
	if (op == op_Conv) {
		ir_node *a_op   = get_Conv_op(a);
		ir_node *b_op   = get_Conv_op(b);
		ir_mode *a_mode = get_irn_mode(a_op);
		ir_mode *b_mode = get_irn_mode(b_op);
		if (a_mode == b_mode && (mode_is_int(a_mode) || a_mode == mode_b)) {
			ir_node *blk = get_nodes_block(n);

			n = exact_copy(n);
			set_binop_left(n, a_op);
			set_binop_right(n, b_op);
			set_irn_mode(n, a_mode);
			n = trans_func(n);
			n = new_r_Conv(blk, n, get_irn_mode(oldn));

			DBG_OPT_ALGSIM1(oldn, a, b, n, FS_OPT_CONV);
			return n;
		}
	}

	if (op == op_Eor) {
		/* nothing to gain here */
		return n;
	}

	if (op == op_Shrs || op == op_Shr || op == op_Shl
			|| op == op_And || op == op_Or || op == op_Eor) {
		ir_node *a_left  = get_binop_left(a);
		ir_node *a_right = get_binop_right(a);
		ir_node *b_left  = get_binop_left(b);
		ir_node *b_right = get_binop_right(b);
		ir_node *c       = NULL;
		ir_node *op1     = NULL;
		ir_node *op2     = NULL;

		if (is_op_commutative(op)) {
			if (a_left == b_left) {
				c   = a_left;
				op1 = a_right;
				op2 = b_right;
			} else if (a_left == b_right) {
				c   = a_left;
				op1 = a_right;
				op2 = b_left;
			} else if (a_right == b_left) {
				c   = a_right;
				op1 = a_left;
				op2 = b_right;
			}
		}
		if (a_right == b_right) {
			c   = a_right;
			op1 = a_left;
			op2 = b_left;
		}

		if (c != NULL) {
			/* (a sop c) & (b sop c) => (a & b) sop c */
			ir_node *blk = get_nodes_block(n);

			ir_node *new_n = exact_copy(n);
			set_binop_left(new_n, op1);
			set_binop_right(new_n, op2);
			new_n = trans_func(new_n);

			if (op_root == op_Eor && op == op_Or) {
				dbg_info  *dbgi = get_irn_dbg_info(n);
				ir_mode   *mode = get_irn_mode(c);

				c = new_rd_Not(dbgi, blk, c, mode);
				n = new_rd_And(dbgi, blk, new_n, c, mode);
			} else {
				n = exact_copy(a);
				set_nodes_block(n, blk);
				set_binop_left(n, new_n);
				set_binop_right(n, c);
				add_identities(n);
			}

			DBG_OPT_ALGSIM1(oldn, a, b, n, FS_OPT_SHIFT_AND);
			return n;
		}
	}

	return n;
}

/**
 * normalisation: (x >> c1) & c2   to   (x & (c2<<c1)) >> c1
 *  (we can use:
 *    - and, or, xor          instead of &
 *    - Shl, Shr, Shrs, rotl  instead of >>
 *    (with a special case for Or/Xor + Shrs)
 *
 * This normalisation is usually good for the backend since << C can often be
 * matched as address-mode.
 */
static ir_node *transform_node_bitop_shift(ir_node *n)
{
	ir_graph  *irg   = get_irn_irg(n);
	ir_node   *left  = get_binop_left(n);
	ir_node   *right = get_binop_right(n);
	ir_mode   *mode  = get_irn_mode(n);
	ir_node   *shift_left;
	ir_node   *shift_right;
	ir_node   *block;
	dbg_info  *dbg_bitop;
	dbg_info  *dbg_shift;
	ir_node   *new_bitop;
	ir_node   *new_shift;
	ir_node   *new_const;
	ir_tarval *tv1;
	ir_tarval *tv2;
	ir_tarval *tv_bitop;

	if (!irg_is_constrained(irg, IR_GRAPH_CONSTRAINT_NORMALISATION2))
		return n;

	assert(is_And(n) || is_Or(n) || is_Eor(n) || is_Or_Eor_Add(n));
	if (!is_Const(right) || !is_shiftop(left))
		return n;

	shift_left  = get_binop_left(left);
	shift_right = get_binop_right(left);
	if (!is_Const(shift_right))
		return n;

	/* doing it with Shrs is not legal if the Or/Eor affects the topmost bit */
	if (is_Shrs(left)) {
		/* TODO this could be improved */
		return n;
	}

	irg       = get_irn_irg(n);
	block     = get_nodes_block(n);
	dbg_bitop = get_irn_dbg_info(n);
	dbg_shift = get_irn_dbg_info(left);
	tv1       = get_Const_tarval(shift_right);
	tv2       = get_Const_tarval(right);
	assert(get_tarval_mode(tv2) == mode);

	if (is_Shl(left)) {
		tv_bitop = tarval_shr(tv2, tv1);

		/* Check whether we have lost some bits during the right shift. */
		if (!is_And(n)) {
			ir_tarval *tv_back_again = tarval_shl(tv_bitop, tv1);

			if (tarval_cmp(tv_back_again, tv2) != ir_relation_equal)
				return n;
		}
	} else if (is_Shr(left)) {
		if (!is_And(n)) {
			/*
			 * TODO this can be improved by checking whether
			 *      the left shift produces an overflow
			 */
			return n;
		}
		tv_bitop = tarval_shl(tv2, tv1);
	} else {
		assert(is_Rotl(left));
		tv_bitop = tarval_rotl(tv2, tarval_neg(tv1));
	}
	new_const = new_r_Const(irg, tv_bitop);

	if (is_And(n)) {
		new_bitop = new_rd_And(dbg_bitop, block, shift_left, new_const, mode);
	} else if (is_Or(n) || is_Or_Eor_Add(n)) {
		new_bitop = new_rd_Or(dbg_bitop, block, shift_left, new_const, mode);
	} else {
		assert(is_Eor(n));
		new_bitop = new_rd_Eor(dbg_bitop, block, shift_left, new_const, mode);
	}

	if (is_Shl(left)) {
		new_shift = new_rd_Shl(dbg_shift, block, new_bitop, shift_right, mode);
	} else if (is_Shr(left)) {
		new_shift = new_rd_Shr(dbg_shift, block, new_bitop, shift_right, mode);
	} else {
		assert(is_Rotl(left));
		new_shift = new_rd_Rotl(dbg_shift, block, new_bitop, shift_right, mode);
	}

	return new_shift;
}

static bool complement_values(const ir_node *a, const ir_node *b)
{
	if (is_Not(a) && get_Not_op(a) == b)
		return true;
	if (is_Not(b) && get_Not_op(b) == a)
		return true;
	if (is_Const(a) && is_Const(b)) {
		ir_tarval *tv_a = get_Const_tarval(a);
		ir_tarval *tv_b = get_Const_tarval(b);
		return tarval_not(tv_a) == tv_b;
	}
	return false;
}

typedef ir_tarval *(tv_fold_binop_func)(ir_tarval *a, ir_tarval *b);

/**
 * for associative operations fold:
 *   op(op(x, c0), c1) to op(x, op(c0, c1)) with constants folded.
 * This is a "light" version of the reassociation phase
 */
static ir_node *fold_constant_associativity(ir_node *node,
                                            tv_fold_binop_func fold)
{
	ir_graph  *irg;
	ir_op     *op;
	ir_node   *left;
	ir_node   *right = get_binop_right(node);
	ir_node   *left_right;
	ir_node   *left_left;
	ir_tarval *c0;
	ir_tarval *c1;
	ir_tarval *new_c;
	ir_node   *new_const;
	ir_node   *new_node;
	if (!is_Const(right))
		return node;

	op   = get_irn_op(node);
	left = get_binop_left(node);
	if (get_irn_op(left) != op)
		return node;

	left_right = get_binop_right(left);
	if (!is_Const(left_right))
		return node;

	left_left = get_binop_left(left);
	c0        = get_Const_tarval(left_right);
	c1        = get_Const_tarval(right);
	irg       = get_irn_irg(node);
	if (get_tarval_mode(c0) != get_tarval_mode(c1))
		return node;
	new_c     = fold(c0, c1);
	if (new_c == tarval_bad)
		return node;
	new_const = new_r_Const(irg, new_c);
	new_node  = exact_copy(node);
	set_binop_left(new_node, left_left);
	set_binop_right(new_node, new_const);
	return new_node;
}

/**
 * Transform an Or.
 */
static ir_node *transform_node_Or_(ir_node *n)
{
	ir_node *oldn = n;
	ir_node *a    = get_binop_left(n);
	ir_node *b    = get_binop_right(n);
	ir_node *c;
	ir_mode *mode;

	n = fold_constant_associativity(n, tarval_or);
	if (n != oldn)
		return n;

	if (is_Not(a) && is_Not(b)) {
		/* ~a | ~b = ~(a&b) */
		ir_node *block = get_nodes_block(n);

		mode = get_irn_mode(n);
		a = get_Not_op(a);
		b = get_Not_op(b);
		n = new_rd_And(get_irn_dbg_info(n), block, a, b, mode);
		n = new_rd_Not(get_irn_dbg_info(n), block, n, mode);
		DBG_OPT_ALGSIM0(oldn, n, FS_OPT_DEMORGAN);
		return n;
	}

	/* we can combine the relations of two compares with the same operands */
	if (is_Cmp(a) && is_Cmp(b)) {
		ir_node *a_left  = get_Cmp_left(a);
		ir_node *a_right = get_Cmp_right(a);
		ir_node *b_left  = get_Cmp_left(b);
		ir_node *b_right = get_Cmp_right(b);
		if (a_left == b_left && b_left == b_right) {
			dbg_info   *dbgi         = get_irn_dbg_info(n);
			ir_node    *block        = get_nodes_block(n);
			ir_relation a_relation   = get_Cmp_relation(a);
			ir_relation b_relation   = get_Cmp_relation(b);
			ir_relation new_relation = a_relation | b_relation;
			return new_rd_Cmp(dbgi, block, a_left, a_right, new_relation);
		}
		/* Cmp(a!=b) or Cmp(c!=d) => Cmp((a^b)|(c^d) != 0) */
		if (is_cmp_unequal(a) && is_cmp_unequal(b)
		    && !mode_is_float(get_irn_mode(a_left))
		    && !mode_is_float(get_irn_mode(b_left))) {
			if (values_in_mode(get_irn_mode(a_left), get_irn_mode(b_left))) {
				ir_graph *irg    = get_irn_irg(n);
				dbg_info *dbgi   = get_irn_dbg_info(n);
				ir_node  *block  = get_nodes_block(n);
				ir_mode  *a_mode = get_irn_mode(a_left);
				ir_mode  *b_mode = get_irn_mode(b_left);
				ir_node  *xora   = new_rd_Eor(dbgi, block, a_left, a_right, a_mode);
				ir_node  *xorb   = new_rd_Eor(dbgi, block, b_left, b_right, b_mode);
				ir_node  *conv   = new_rd_Conv(dbgi, block, xora, b_mode);
				ir_node  *orn    = new_rd_Or(dbgi, block, conv, xorb, b_mode);
				ir_node  *zero   = create_zero_const(irg, b_mode);
				return new_rd_Cmp(dbgi, block, orn, zero, ir_relation_less_greater);
			}
			if (values_in_mode(get_irn_mode(b_left), get_irn_mode(a_left))) {
				ir_graph *irg    = get_irn_irg(n);
				dbg_info *dbgi   = get_irn_dbg_info(n);
				ir_node  *block  = get_nodes_block(n);
				ir_mode  *a_mode = get_irn_mode(a_left);
				ir_mode  *b_mode = get_irn_mode(b_left);
				ir_node  *xora   = new_rd_Eor(dbgi, block, a_left, a_right, a_mode);
				ir_node  *xorb   = new_rd_Eor(dbgi, block, b_left, b_right, b_mode);
				ir_node  *conv   = new_rd_Conv(dbgi, block, xorb, a_mode);
				ir_node  *orn    = new_rd_Or(dbgi, block, xora, conv, a_mode);
				ir_node  *zero   = create_zero_const(irg, a_mode);
				return new_rd_Cmp(dbgi, block, orn, zero, ir_relation_less_greater);
			}
		}
	}

	mode = get_irn_mode(n);
	HANDLE_BINOP_PHI((eval_func) tarval_or, a, b, c, mode);

	n = transform_node_Or_bf_store(n);
	if (n != oldn)
		return n;
	n = transform_node_Or_Rotl(n);
	if (n != oldn)
		return n;

	n = transform_bitwise_distributive(n, transform_node_Or_);
	if (n != oldn)
		return n;
	n = transform_node_bitop_shift(n);
	if (n != oldn)
		return n;

	return n;
}

static ir_node *transform_node_Or(ir_node *n)
{
	if (is_Or_Eor_Add(n)) {
		dbg_info *dbgi  = get_irn_dbg_info(n);
		ir_node  *block = get_nodes_block(n);
		ir_node  *left  = get_Or_left(n);
		ir_node  *right = get_Or_right(n);
		ir_mode  *mode  = get_irn_mode(n);
		return new_rd_Add(dbgi, block, left, right, mode);
	}
	return transform_node_Or_(n);
}

/**
 * Transform an Eor.
 */
static ir_node *transform_node_Eor_(ir_node *n)
{
	ir_node *oldn = n;
	ir_node *a    = get_binop_left(n);
	ir_node *b    = get_binop_right(n);
	ir_mode *mode = get_irn_mode(n);
	ir_node *c;

	n = fold_constant_associativity(n, tarval_eor);
	if (n != oldn)
		return n;

	/* we can combine the relations of two compares with the same operands */
	if (is_Cmp(a) && is_Cmp(b)) {
		ir_node *a_left  = get_Cmp_left(a);
		ir_node *a_right = get_Cmp_left(a);
		ir_node *b_left  = get_Cmp_left(b);
		ir_node *b_right = get_Cmp_right(b);
		if (a_left == b_left && b_left == b_right) {
			dbg_info   *dbgi         = get_irn_dbg_info(n);
			ir_node    *block        = get_nodes_block(n);
			ir_relation a_relation   = get_Cmp_relation(a);
			ir_relation b_relation   = get_Cmp_relation(b);
			ir_relation new_relation = a_relation ^ b_relation;
			return new_rd_Cmp(dbgi, block, a_left, a_right, new_relation);
		}
	}

	HANDLE_BINOP_PHI((eval_func) tarval_eor, a, b, c, mode);

	/* normalize not nodes... ~a ^ b <=> a ^ ~b */
	if (is_Not(a) && operands_are_normalized(get_Not_op(a), b)) {
		dbg_info *dbg      = get_irn_dbg_info(n);
		ir_node  *block    = get_nodes_block(n);
		ir_node  *new_not  = new_rd_Not(dbg, block, b, mode);
		ir_node  *new_left = get_Not_op(a);
		n = new_rd_Eor(dbg, block, new_left, new_not, mode);
		DBG_OPT_ALGSIM0(oldn, n, FS_OPT_EOR_TO_NOT);
		return n;
	} else if (is_Not(b) && !operands_are_normalized(a, get_Not_op(b))) {
		dbg_info *dbg       = get_irn_dbg_info(n);
		ir_node  *block     = get_nodes_block(n);
		ir_node  *new_not   = new_rd_Not(dbg, block, a, mode);
		ir_node  *new_right = get_Not_op(b);
		n = new_rd_Eor(dbg, block, new_not, new_right, mode);
		DBG_OPT_ALGSIM0(oldn, n, FS_OPT_EOR_TO_NOT);
		return n;
	}

	/* x ^ 1...1 -> ~1 */
	if (is_Const(b) && is_Const_all_one(b)) {
		n = new_r_Not(get_nodes_block(n), a, mode);
		DBG_OPT_ALGSIM0(oldn, n, FS_OPT_EOR_TO_NOT);
		return n;
	}

	n = transform_bitwise_distributive(n, transform_node_Eor_);
	if (n != oldn)
		return n;
	n = transform_node_bitop_shift(n);
	if (n != oldn)
		return n;

	return n;
}

static ir_node *transform_node_Eor(ir_node *n)
{
	if (is_Or_Eor_Add(n)) {
		dbg_info *dbgi  = get_irn_dbg_info(n);
		ir_node  *block = get_nodes_block(n);
		ir_node  *left  = get_Eor_left(n);
		ir_node  *right = get_Eor_right(n);
		ir_mode  *mode  = get_irn_mode(n);
		return new_rd_Add(dbgi, block, left, right, mode);
	}
	return transform_node_Eor_(n);
}

/**
 * Do the AddSub optimization, then Transform
 *   Constant folding on Phi
 *   Add(a,a)          -> Mul(a, 2)
 *   Add(Mul(a, x), a) -> Mul(a, x+1)
 * if the mode is integer or float.
 * Transform Add(a,-b) into Sub(a,b).
 * Reassociation might fold this further.
 */
static ir_node *transform_node_Add(ir_node *n)
{
	ir_mode *mode;
	ir_node *a;
	ir_node *b;
	ir_node *c;
	ir_node *oldn = n;

	n = fold_constant_associativity(n, tarval_add);
	if (n != oldn)
		return n;

	n = transform_node_AddSub(n);
	if (n != oldn)
		return n;

	a    = get_Add_left(n);
	b    = get_Add_right(n);
	mode = get_irn_mode(n);

	if (mode_is_reference(mode)) {
		ir_mode *lmode = get_irn_mode(a);

		if (is_Const(b) && is_Const_null(b) && mode_is_int(lmode)) {
			/* an Add(a, NULL) is a hidden Conv */
			dbg_info *dbg = get_irn_dbg_info(n);
			return new_rd_Conv(dbg, get_nodes_block(n), a, mode);
		}
	}

	if (is_Const(b) && get_mode_arithmetic(mode) == irma_twos_complement) {
		ir_tarval *tv  = get_Const_tarval(b);
		ir_tarval *min = get_mode_min(mode);
		/* if all bits are set, then this has the same effect as a Not.
		 * Note that the following == gives false for different modes which
		 * is exactly what we want */
		if (tv == min) {
			dbg_info *dbgi  = get_irn_dbg_info(n);
			ir_graph *irg   = get_irn_irg(n);
			ir_node  *block = get_nodes_block(n);
			ir_node  *cnst  = new_r_Const(irg, min);
			return new_rd_Eor(dbgi, block, a, cnst, mode);
		}
	}

	HANDLE_BINOP_PHI((eval_func) tarval_add, a, b, c, mode);

	/* for FP the following optimizations are only allowed if
	 * fp_strict_algebraic is disabled */
	if (mode_is_float(mode)) {
		ir_graph *irg = get_irn_irg(n);
		if (get_irg_fp_model(irg) & fp_strict_algebraic)
			return n;
	}

	if (mode_is_num(mode)) {
		ir_graph *irg = get_irn_irg(n);
		/* the following code leads to endless recursion when Mul are replaced
		 * by a simple instruction chain */
		if (!irg_is_constrained(irg, IR_GRAPH_CONSTRAINT_ARCH_DEP)
				&& a == b && mode_is_int(mode)) {
			ir_node *block = get_nodes_block(n);

			n = new_rd_Mul(
				get_irn_dbg_info(n),
				block,
				a,
				new_r_Const_long(irg, mode, 2),
				mode);
			DBG_OPT_ALGSIM0(oldn, n, FS_OPT_ADD_A_A);
			return n;
		}
		if (is_Minus(a)) {
			n = new_rd_Sub(
					get_irn_dbg_info(n),
					get_nodes_block(n),
					b,
					get_Minus_op(a),
					mode);
			DBG_OPT_ALGSIM0(oldn, n, FS_OPT_ADD_A_MINUS_B);
			return n;
		}
		if (is_Minus(b)) {
			n = new_rd_Sub(
					get_irn_dbg_info(n),
					get_nodes_block(n),
					a,
					get_Minus_op(b),
					mode);
			DBG_OPT_ALGSIM0(oldn, n, FS_OPT_ADD_A_MINUS_B);
			return n;
		}
		if (get_mode_arithmetic(mode) == irma_twos_complement) {
			/* Here we rely on constants be on the RIGHT side */
			if (is_Not(a)) {
				ir_node *op = get_Not_op(a);

				if (is_Const(b) && is_Const_one(b)) {
					/* ~x + 1 = -x */
					ir_node *blk = get_nodes_block(n);
					n = new_rd_Minus(get_irn_dbg_info(n), blk, op, mode);
					DBG_OPT_ALGSIM0(oldn, n, FS_OPT_NOT_PLUS_1);
					return n;
				}
			}
		}
	}

	if (is_Or_Eor_Add(n)) {
		n = transform_node_Or_(n);
		if (n != oldn)
			return n;
		n = transform_node_Eor_(n);
		if (n != oldn)
			return n;
	}

	return n;
}

/**
 * returns -cnst or NULL if impossible
 */
static ir_node *const_negate(ir_node *cnst)
{
	ir_tarval *tv    = tarval_neg(get_Const_tarval(cnst));
	dbg_info  *dbgi  = get_irn_dbg_info(cnst);
	ir_graph  *irg   = get_irn_irg(cnst);
	if (tv == tarval_bad) return NULL;
	return new_rd_Const(dbgi, irg, tv);
}

/**
 * Do the AddSub optimization, then Transform
 *   Constant folding on Phi
 *   Sub(0,a)          -> Minus(a)
 *   Sub(Mul(a, x), a) -> Mul(a, x-1)
 *   Sub(Sub(x, y), b) -> Sub(x, Add(y,b))
 *   Sub(Add(a, x), x) -> a
 *   Sub(x, Add(x, a)) -> -a
 *   Sub(x, Const)     -> Add(x, -Const)
 */
static ir_node *transform_node_Sub(ir_node *n)
{
	ir_mode *mode;
	ir_node *oldn = n;
	ir_node *a, *b, *c;

	n = transform_node_AddSub(n);

	a = get_Sub_left(n);
	b = get_Sub_right(n);

	mode = get_irn_mode(n);

	if (mode_is_int(mode)) {
		ir_mode *lmode = get_irn_mode(a);

		if (is_Const(b) && is_Const_null(b) && mode_is_reference(lmode)) {
			/* a Sub(a, NULL) is a hidden Conv */
			dbg_info *dbg = get_irn_dbg_info(n);
			n = new_rd_Conv(dbg, get_nodes_block(n), a, mode);
			DBG_OPT_ALGSIM0(oldn, n, FS_OPT_SUB_TO_CONV);
			return n;
		}

		if (mode == lmode                                     &&
		    get_mode_arithmetic(mode) == irma_twos_complement &&
		    is_Const(a)                                       &&
		    get_Const_tarval(a) == get_mode_minus_one(mode)) {
			/* -1 - x -> ~x */
			dbg_info *dbg = get_irn_dbg_info(n);
			n = new_rd_Not(dbg, get_nodes_block(n), b, mode);
			DBG_OPT_ALGSIM0(oldn, n, FS_OPT_SUB_TO_NOT);
			return n;
		}
	}

restart:
	HANDLE_BINOP_PHI((eval_func) tarval_sub, a, b, c, mode);

	/* for FP these optimizations are only allowed if fp_strict_algebraic is disabled */
	if (mode_is_float(mode)) {
		ir_graph *irg = get_irn_irg(n);
		if (get_irg_fp_model(irg) & fp_strict_algebraic)
			return n;
	}

	if (is_Const(b) && !mode_is_reference(get_irn_mode(b))) {
		/* a - C -> a + (-C) */
		ir_node *cnst = const_negate(b);
		if (cnst != NULL) {
			ir_node  *block = get_nodes_block(n);
			dbg_info *dbgi  = get_irn_dbg_info(n);

			n = new_rd_Add(dbgi, block, a, cnst, mode);
			DBG_OPT_ALGSIM0(oldn, n, FS_OPT_SUB_TO_ADD);
			return n;
		}
	}

	if (is_Minus(a)) { /* (-a) - b -> -(a + b) */
		dbg_info *dbg   = get_irn_dbg_info(n);
		ir_node  *block = get_nodes_block(n);
		ir_node  *left  = get_Minus_op(a);
		ir_node  *add   = new_rd_Add(dbg, block, left, b, mode);

		n = new_rd_Minus(dbg, block, add, mode);
		DBG_OPT_ALGSIM0(oldn, n, FS_OPT_SUB_TO_ADD);
		return n;
	} else if (is_Minus(b)) { /* a - (-b) -> a + b */
		dbg_info *dbg   = get_irn_dbg_info(n);
		ir_node  *block = get_nodes_block(n);
		ir_node  *right = get_Minus_op(b);

		n = new_rd_Add(dbg, block, a, right, mode);
		DBG_OPT_ALGSIM0(oldn, n, FS_OPT_SUB_MINUS);
		return n;
	} else if (is_Sub(b)) {
		/* a - (b - c) -> a + (c - b)
		 *             -> (a - b) + c iff (b - c) is a pointer */
		dbg_info *s_dbg   = get_irn_dbg_info(b);
		ir_node  *s_left  = get_Sub_left(b);
		ir_node  *s_right = get_Sub_right(b);
		ir_mode  *s_mode  = get_irn_mode(b);
		if (mode_is_reference(s_mode)) {
			ir_node  *lowest_block = get_nodes_block(n); /* a and b are live here */
			ir_node  *sub     = new_rd_Sub(s_dbg, lowest_block, a, s_left, mode);
			dbg_info *a_dbg   = get_irn_dbg_info(n);

			if (s_mode != mode)
				s_right = new_r_Conv(lowest_block, s_right, mode);
			n = new_rd_Add(a_dbg, lowest_block, sub, s_right, mode);
		} else {
			ir_node  *s_block = get_nodes_block(b);
			ir_node  *sub     = new_rd_Sub(s_dbg, s_block, s_right, s_left, s_mode);
			dbg_info *a_dbg   = get_irn_dbg_info(n);
			ir_node  *a_block = get_nodes_block(n);

			n = new_rd_Add(a_dbg, a_block, a, sub, mode);
		}
		DBG_OPT_ALGSIM0(oldn, n, FS_OPT_SUB_TO_ADD);
		return n;
#if 0
	} else if (is_Mul(b)) { /* a - (b * C) -> a + (b * -C) */
		ir_node *m_right = get_Mul_right(b);
		if (is_Const(m_right)) {
			ir_node *cnst2 = const_negate(m_right);
			if (cnst2 != NULL) {
				dbg_info *m_dbg   = get_irn_dbg_info(b);
				ir_node  *m_block = get_nodes_block(b);
				ir_node  *m_left  = get_Mul_left(b);
				ir_mode  *m_mode  = get_irn_mode(b);
				ir_node  *mul     = new_rd_Mul(m_dbg, m_block, m_left, cnst2, m_mode);
				dbg_info *a_dbg   = get_irn_dbg_info(n);
				ir_node  *a_block = get_nodes_block(n);

				n = new_rd_Add(a_dbg, a_block, a, mul, mode);
				DBG_OPT_ALGSIM0(oldn, n, FS_OPT_SUB_TO_ADD);
				return n;
			}
		}
#endif
	}

	/* Beware of Sub(P, P) which cannot be optimized into a simple Minus ... */
	if (mode_is_num(mode) && mode == get_irn_mode(a) && is_Const(a) && is_Const_null(a)) {
		n = new_rd_Minus(
				get_irn_dbg_info(n),
				get_nodes_block(n),
				b,
				mode);
		DBG_OPT_ALGSIM0(oldn, n, FS_OPT_SUB_0_A);
		return n;
	}
	if ((is_Add(a) || is_Or_Eor_Add(a)) && mode_wrap_around(mode)) {
		ir_node *left  = get_binop_left(a);
		ir_node *right = get_binop_right(a);

		/* FIXME: Does the Conv's work only for two complement or generally? */
		if (left == b) {
			if (mode != get_irn_mode(right)) {
				/* This Sub is an effective Cast */
				right = new_r_Conv(get_nodes_block(n), right, mode);
			}
			n = right;
			DBG_OPT_ALGSIM1(oldn, a, b, n, FS_OPT_ADD_SUB);
			return n;
		} else if (right == b) {
			if (mode != get_irn_mode(left)) {
				/* This Sub is an effective Cast */
				left = new_r_Conv(get_nodes_block(n), left, mode);
			}
			n = left;
			DBG_OPT_ALGSIM1(oldn, a, b, n, FS_OPT_ADD_SUB);
			return n;
		}
	}
	if ((is_Add(b) || is_Or_Eor_Add(b)) && mode_wrap_around(mode)) {
		ir_node *left  = get_binop_left(b);
		ir_node *right = get_binop_right(b);

		/* FIXME: Does the Conv's work only for two complement or generally? */
		if (left == a) {
			ir_mode *r_mode = get_irn_mode(right);

			n = new_r_Minus(get_nodes_block(n), right, r_mode);
			if (mode != r_mode) {
				/* This Sub is an effective Cast */
				n = new_r_Conv(get_nodes_block(n), n, mode);
			}
			DBG_OPT_ALGSIM1(oldn, a, b, n, FS_OPT_ADD_SUB);
			return n;
		} else if (right == a) {
			ir_mode *l_mode = get_irn_mode(left);

			n = new_r_Minus(get_nodes_block(n), left, l_mode);
			if (mode != l_mode) {
				/* This Sub is an effective Cast */
				n = new_r_Conv(get_nodes_block(n), n, mode);
			}
			DBG_OPT_ALGSIM1(oldn, a, b, n, FS_OPT_ADD_SUB);
			return n;
		}
	}
	if (mode_is_int(mode) && is_Conv(a) && is_Conv(b)) {
		ir_mode *mode = get_irn_mode(a);

		if (mode == get_irn_mode(b)) {
			ir_mode *ma, *mb;
			ir_node *op_a = get_Conv_op(a);
			ir_node *op_b = get_Conv_op(b);

			/* check if it's allowed to skip the conv */
			ma = get_irn_mode(op_a);
			mb = get_irn_mode(op_b);

			if (mode_is_reference(ma) && mode_is_reference(mb)) {
				/* SubInt(ConvInt(aP), ConvInt(bP)) -> SubInt(aP,bP) */
				a = op_a; b = op_b;
				set_Sub_left(n, a);
				set_Sub_right(n, b);

				goto restart;
			}
		}
	}
	/* do NOT execute this code if reassociation is enabled, it does the inverse! */
	if (!is_reassoc_running() && is_Mul(a)) {
		ir_node *ma = get_Mul_left(a);
		ir_node *mb = get_Mul_right(a);

		if (ma == b) {
			ir_node  *blk = get_nodes_block(n);
			ir_graph *irg = get_irn_irg(n);
			n = new_rd_Mul(
					get_irn_dbg_info(n),
					blk,
					ma,
					new_rd_Sub(
						get_irn_dbg_info(n),
						blk,
						mb,
						new_r_Const(irg, get_mode_one(mode)),
						mode),
					mode);
			DBG_OPT_ALGSIM0(oldn, n, FS_OPT_SUB_MUL_A_X_A);
			return n;
		} else if (mb == b) {
			ir_node  *blk = get_nodes_block(n);
			ir_graph *irg = get_irn_irg(n);
			n = new_rd_Mul(
					get_irn_dbg_info(n),
					blk,
					mb,
					new_rd_Sub(
						get_irn_dbg_info(n),
						blk,
						ma,
						new_r_Const(irg, get_mode_one(mode)),
						mode),
					mode);
			DBG_OPT_ALGSIM0(oldn, n, FS_OPT_SUB_MUL_A_X_A);
			return n;
		}
	}
	if (is_Sub(a)) { /* (x - y) - b -> x - (y + b) */
		ir_node *x        = get_Sub_left(a);
		ir_node *y        = get_Sub_right(a);
		ir_node *blk      = get_nodes_block(n);
		ir_mode *m_b      = get_irn_mode(b);
		ir_mode *m_y      = get_irn_mode(y);
		ir_mode *add_mode;
		ir_node *add;

		/* Determine the right mode for the Add. */
		if (m_b == m_y)
			add_mode = m_b;
		else if (mode_is_reference(m_b))
			add_mode = m_b;
		else if (mode_is_reference(m_y))
			add_mode = m_y;
		else {
			/*
			 * Both modes are different but none is reference,
			 * happens for instance in SubP(SubP(P, Iu), Is).
			 * We have two possibilities here: Cast or ignore.
			 * Currently we ignore this case.
			 */
			return n;
		}

		add = new_r_Add(blk, y, b, add_mode);

		n = new_rd_Sub(get_irn_dbg_info(n), blk, x, add, mode);
		DBG_OPT_ALGSIM0(oldn, n, FS_OPT_SUB_SUB_X_Y_Z);
		return n;
	}

	if (get_mode_arithmetic(mode) == irma_twos_complement) {
		/* c - ~X = X + (c+1) */
		if (is_Const(a) && is_Not(b)) {
			ir_tarval *tv = get_Const_tarval(a);

			tv = tarval_add(tv, get_mode_one(mode));
			if (tv != tarval_bad) {
				ir_node  *blk = get_nodes_block(n);
				ir_graph *irg = get_irn_irg(n);
				ir_node *c = new_r_Const(irg, tv);
				n = new_rd_Add(get_irn_dbg_info(n), blk, get_Not_op(b), c, mode);
				DBG_OPT_ALGSIM0(oldn, n, FS_OPT_SUB_C_NOT_X);
				return n;
			}
		}
		/* x-(x&y) = x & ~y */
		if (is_And(b)) {
			ir_node *and_left  = get_And_left(b);
			ir_node *and_right = get_And_right(b);
			if (and_right == a) {
				ir_node *tmp = and_left;
				and_left  = and_right;
				and_right = tmp;
			}
			if (and_left == a) {
				dbg_info *dbgi  = get_irn_dbg_info(n);
				ir_node  *block = get_nodes_block(n);
				ir_mode  *mode  = get_irn_mode(n);
				ir_node  *notn  = new_rd_Not(dbgi, block, and_right, mode);
				ir_node  *andn  = new_rd_And(dbgi, block, a, notn, mode);
				return andn;
			}
		}
	}
	return n;
}

/**
 * Several transformation done on n*n=2n bits mul.
 * These transformations must be done here because new nodes may be produced.
 */
static ir_node *transform_node_Mul2n(ir_node *n, ir_mode *mode)
{
	ir_node   *oldn  = n;
	ir_node   *a     = get_Mul_left(n);
	ir_node   *b     = get_Mul_right(n);
	ir_tarval *ta    = value_of(a);
	ir_tarval *tb    = value_of(b);
	ir_mode   *smode = get_irn_mode(a);

	if (ta == get_mode_one(smode)) {
		/* (L)1 * (L)b = (L)b */
		ir_node *blk = get_nodes_block(n);
		n = new_rd_Conv(get_irn_dbg_info(n), blk, b, mode);
		DBG_OPT_ALGSIM1(oldn, a, b, n, FS_OPT_NEUTRAL_1);
		return n;
	}
	else if (ta == get_mode_minus_one(smode)) {
		/* (L)-1 * (L)b = (L)b */
		ir_node *blk = get_nodes_block(n);
		n = new_rd_Minus(get_irn_dbg_info(n), blk, b, smode);
		n = new_rd_Conv(get_irn_dbg_info(n), blk, n, mode);
		DBG_OPT_ALGSIM1(oldn, a, b, n, FS_OPT_MUL_MINUS_1);
		return n;
	}
	if (tb == get_mode_one(smode)) {
		/* (L)a * (L)1 = (L)a */
		ir_node *blk = get_nodes_block(a);
		n = new_rd_Conv(get_irn_dbg_info(n), blk, a, mode);
		DBG_OPT_ALGSIM1(oldn, a, b, n, FS_OPT_NEUTRAL_1);
		return n;
	}
	else if (tb == get_mode_minus_one(smode)) {
		/* (L)a * (L)-1 = (L)-a */
		ir_node *blk = get_nodes_block(n);
		n = new_rd_Minus(get_irn_dbg_info(n), blk, a, smode);
		n = new_rd_Conv(get_irn_dbg_info(n), blk, n, mode);
		DBG_OPT_ALGSIM1(oldn, a, b, n, FS_OPT_MUL_MINUS_1);
		return n;
	}
	return n;
}

/**
 * Transform Mul(a,-1) into -a.
 * Do constant evaluation of Phi nodes.
 * Do architecture dependent optimizations on Mul nodes
 */
static ir_node *transform_node_Mul(ir_node *n)
{
	ir_node *c, *oldn = n;
	ir_mode *mode = get_irn_mode(n);
	ir_node *a = get_Mul_left(n);
	ir_node *b = get_Mul_right(n);

	n = fold_constant_associativity(n, tarval_mul);
	if (n != oldn)
		return n;

	if (mode != get_irn_mode(a))
		return transform_node_Mul2n(n, mode);

	HANDLE_BINOP_PHI((eval_func) tarval_mul, a, b, c, mode);

	if (mode_is_signed(mode)) {
		ir_node *r = NULL;

		if (value_of(a) == get_mode_minus_one(mode))
			r = b;
		else if (value_of(b) == get_mode_minus_one(mode))
			r = a;
		if (r) {
			n = new_rd_Minus(get_irn_dbg_info(n), get_nodes_block(n), r, mode);
			DBG_OPT_ALGSIM1(oldn, a, b, n, FS_OPT_MUL_MINUS_1);
			return n;
		}
	}
	if (is_Minus(a)) {
		if (is_Const(b)) { /* (-a) * const -> a * -const */
			ir_node *cnst = const_negate(b);
			if (cnst != NULL) {
				dbg_info *dbgi  = get_irn_dbg_info(n);
				ir_node  *block = get_nodes_block(n);
				n = new_rd_Mul(dbgi, block, get_Minus_op(a), cnst, mode);
				DBG_OPT_ALGSIM1(oldn, a, b, n, FS_OPT_MUL_MINUS_1);
				return n;
			}
		} else if (is_Minus(b)) { /* (-a) * (-b) -> a * b */
			dbg_info *dbgi  = get_irn_dbg_info(n);
			ir_node  *block = get_nodes_block(n);
			n = new_rd_Mul(dbgi, block, get_Minus_op(a), get_Minus_op(b), mode);
			DBG_OPT_ALGSIM1(oldn, a, b, n, FS_OPT_MUL_MINUS_MINUS);
			return n;
		} else if (is_Sub(b)) { /* (-a) * (b - c) -> a * (c - b) */
			ir_node  *sub_l = get_Sub_left(b);
			ir_node  *sub_r = get_Sub_right(b);
			dbg_info *dbgi  = get_irn_dbg_info(n);
			ir_node  *block = get_nodes_block(n);
			ir_node  *new_b = new_rd_Sub(dbgi, block, sub_r, sub_l, mode);
			n = new_rd_Mul(dbgi, block, get_Minus_op(a), new_b, mode);
			DBG_OPT_ALGSIM1(oldn, a, b, n, FS_OPT_MUL_MINUS);
			return n;
		}
	} else if (is_Minus(b)) {
		if (is_Sub(a)) { /* (a - b) * (-c) -> (b - a) * c */
			ir_node  *sub_l = get_Sub_left(a);
			ir_node  *sub_r = get_Sub_right(a);
			dbg_info *dbgi  = get_irn_dbg_info(n);
			ir_node  *block = get_nodes_block(n);
			ir_node  *new_a = new_rd_Sub(dbgi, block, sub_r, sub_l, mode);
			n = new_rd_Mul(dbgi, block, new_a, get_Minus_op(b), mode);
			DBG_OPT_ALGSIM1(oldn, a, b, n, FS_OPT_MUL_MINUS);
			return n;
		}
	} else if (is_Shl(a)) {
		ir_node *const shl_l = get_Shl_left(a);
		if (is_Const(shl_l) && is_Const_one(shl_l)) {
			/* (1 << x) * b -> b << x */
			dbg_info *const dbgi  = get_irn_dbg_info(n);
			ir_node  *const block = get_nodes_block(n);
			ir_node  *const shl_r = get_Shl_right(a);
			n = new_rd_Shl(dbgi, block, b, shl_r, mode);
			// TODO add me DBG_OPT_ALGSIM1(oldn, a, b, n, FS_OPT_MUL_SHIFT);
			return n;
		}
	} else if (is_Shl(b)) {
		ir_node *const shl_l = get_Shl_left(b);
		if (is_Const(shl_l) && is_Const_one(shl_l)) {
			/* a * (1 << x) -> a << x */
			dbg_info *const dbgi  = get_irn_dbg_info(n);
			ir_node  *const block = get_nodes_block(n);
			ir_node  *const shl_r = get_Shl_right(b);
			n = new_rd_Shl(dbgi, block, a, shl_r, mode);
			// TODO add me DBG_OPT_ALGSIM1(oldn, a, b, n, FS_OPT_MUL_SHIFT);
			return n;
		}
	}
	if (get_mode_arithmetic(mode) == irma_ieee754
	    || get_mode_arithmetic(mode) == irma_x86_extended_float) {
		if (is_Const(a)) {
			ir_tarval *tv = get_Const_tarval(a);
			if (tarval_get_exponent(tv) == 1 && tarval_zero_mantissa(tv)
					&& !tarval_is_negative(tv)) {
				/* 2.0 * b = b + b */
				n = new_rd_Add(get_irn_dbg_info(n), get_nodes_block(n), b, b, mode);
				DBG_OPT_ALGSIM1(oldn, a, b, n, FS_OPT_ADD_A_A);
				return n;
			}
		}
		else if (is_Const(b)) {
			ir_tarval *tv = get_Const_tarval(b);
			if (tarval_get_exponent(tv) == 1 && tarval_zero_mantissa(tv)
					&& !tarval_is_negative(tv)) {
				/* a * 2.0 = a + a */
				n = new_rd_Add(get_irn_dbg_info(n), get_nodes_block(n), a, a, mode);
				DBG_OPT_ALGSIM1(oldn, a, b, n, FS_OPT_ADD_A_A);
				return n;
			}
		}
	}
	return arch_dep_replace_mul_with_shifts(n);
}

/**
 * Transform a Div Node.
 */
static ir_node *transform_node_Div(ir_node *n)
{
	ir_mode *mode = get_Div_resmode(n);
	ir_node *a = get_Div_left(n);
	ir_node *b = get_Div_right(n);
	ir_node *value = n;
	const ir_node *dummy;

	if (mode_is_int(mode)) {
		if (is_Const(b) && is_const_Phi(a)) {
			/* check for Div(Phi, Const) */
			value = apply_binop_on_phi(a, get_Const_tarval(b), (eval_func) tarval_div, mode, 0);
			if (value) {
				DBG_OPT_ALGSIM0(n, value, FS_OPT_CONST_PHI);
				goto make_tuple;
			}
		} else if (is_Const(a) && is_const_Phi(b)) {
			/* check for Div(Const, Phi) */
			value = apply_binop_on_phi(b, get_Const_tarval(a), (eval_func) tarval_div, mode, 1);
			if (value) {
				DBG_OPT_ALGSIM0(n, value, FS_OPT_CONST_PHI);
				goto make_tuple;
			}
		} else if (is_const_Phi(a) && is_const_Phi(b)) {
			/* check for Div(Phi, Phi) */
			value = apply_binop_on_2_phis(a, b, (eval_func) tarval_div, mode);
			if (value) {
				DBG_OPT_ALGSIM0(n, value, FS_OPT_CONST_PHI);
				goto make_tuple;
			}
		}

		if (a == b && value_not_zero(a, &dummy)) {
			ir_graph *irg = get_irn_irg(n);
			/* BEWARE: we can optimize a/a to 1 only if this cannot cause a exception */
			value = new_r_Const(irg, get_mode_one(mode));
			DBG_OPT_CSTEVAL(n, value);
			goto make_tuple;
		} else {
			if (mode_is_signed(mode) && is_Const(b)) {
				ir_tarval *tv = get_Const_tarval(b);

				if (tv == get_mode_minus_one(mode)) {
					/* a / -1 */
					value = new_rd_Minus(get_irn_dbg_info(n), get_nodes_block(n), a, mode);
					DBG_OPT_CSTEVAL(n, value);
					goto make_tuple;
				}
			}
			/* Try architecture dependent optimization */
			value = arch_dep_replace_div_by_const(n);
		}
	} else {
		assert(mode_is_float(mode));

		/* Optimize x/c to x*(1/c) */
		if (get_mode_arithmetic(mode) == irma_ieee754) {
			ir_tarval *tv = value_of(b);

			if (tv != tarval_bad) {
				int rem = tarval_fp_ops_enabled();

				/*
				 * Floating point constant folding might be disabled here to
				 * prevent rounding.
				 * However, as we check for exact result, doing it is safe.
				 * Switch it on.
				 */
				tarval_enable_fp_ops(1);
				tv = tarval_div(get_mode_one(mode), tv);
				tarval_enable_fp_ops(rem);

				/* Do the transformation if the result is either exact or we are
				   not using strict rules. */
				if (tv != tarval_bad &&
					(tarval_ieee754_get_exact() || (get_irg_fp_model(get_irn_irg(n)) & fp_strict_algebraic) == 0)) {
					ir_node  *block = get_nodes_block(n);
					ir_graph *irg   = get_irn_irg(block);
					ir_node  *c     = new_r_Const(irg, tv);
					dbg_info *dbgi  = get_irn_dbg_info(n);
					value = new_rd_Mul(dbgi, block, a, c, mode);

					goto make_tuple;
				}
			}
		}
	}

	if (value != n) {
		ir_node *mem, *blk;
		ir_graph *irg;

make_tuple:
		/* Turn Div into a tuple (mem, jmp, bad, value) */
		mem = get_Div_mem(n);
		blk = get_nodes_block(n);
		irg = get_irn_irg(blk);

		/* skip a potential Pin */
		mem = skip_Pin(mem);
		turn_into_tuple(n, pn_Div_max+1);
		set_Tuple_pred(n, pn_Div_M,         mem);
		set_Tuple_pred(n, pn_Div_X_regular, new_r_Jmp(blk));
		set_Tuple_pred(n, pn_Div_X_except,  new_r_Bad(irg, mode_X));
		set_Tuple_pred(n, pn_Div_res,       value);
	}
	return n;
}

/**
 * Transform a Mod node.
 */
static ir_node *transform_node_Mod(ir_node *n)
{
	ir_mode   *mode = get_Mod_resmode(n);
	ir_node   *a    = get_Mod_left(n);
	ir_node   *b    = get_Mod_right(n);
	ir_graph  *irg;
	ir_node   *value;
	ir_tarval *tv;

	if (is_Const(b) && is_const_Phi(a)) {
		/* check for Div(Phi, Const) */
		value = apply_binop_on_phi(a, get_Const_tarval(b), (eval_func) tarval_mod, mode, 0);
		if (value) {
			DBG_OPT_ALGSIM0(n, value, FS_OPT_CONST_PHI);
			goto make_tuple;
		}
	}
	else if (is_Const(a) && is_const_Phi(b)) {
		/* check for Div(Const, Phi) */
		value = apply_binop_on_phi(b, get_Const_tarval(a), (eval_func) tarval_mod, mode, 1);
		if (value) {
			DBG_OPT_ALGSIM0(n, value, FS_OPT_CONST_PHI);
			goto make_tuple;
		}
	}
	else if (is_const_Phi(a) && is_const_Phi(b)) {
		/* check for Div(Phi, Phi) */
		value = apply_binop_on_2_phis(a, b, (eval_func) tarval_mod, mode);
		if (value) {
			DBG_OPT_ALGSIM0(n, value, FS_OPT_CONST_PHI);
			goto make_tuple;
		}
	}

	value = n;
	tv = value_of(n);
	irg = get_irn_irg(n);
	if (tv != tarval_bad) {
		value = new_r_Const(irg, tv);

		DBG_OPT_CSTEVAL(n, value);
		goto make_tuple;
	} else {
		ir_node       *a = get_Mod_left(n);
		ir_node       *b = get_Mod_right(n);
		const ir_node *dummy;

		if (a == b && value_not_zero(a, &dummy)) {
			/* BEWARE: we can optimize a%a to 0 only if this cannot cause a exception */
			value = new_r_Const(irg, get_mode_null(mode));
			DBG_OPT_CSTEVAL(n, value);
			goto make_tuple;
		} else {
			if (mode_is_signed(mode) && is_Const(b)) {
				ir_tarval *tv = get_Const_tarval(b);

				if (tv == get_mode_minus_one(mode)) {
					/* a % -1 = 0 */
					value = new_r_Const(irg, get_mode_null(mode));
					DBG_OPT_CSTEVAL(n, value);
					goto make_tuple;
				}
			}
			/* Try architecture dependent optimization */
			value = arch_dep_replace_mod_by_const(n);
		}
	}

	if (value != n) {
		ir_node *mem, *blk;
		ir_graph *irg;

make_tuple:
		/* Turn Mod into a tuple (mem, jmp, bad, value) */
		mem = get_Mod_mem(n);
		blk = get_nodes_block(n);
		irg = get_irn_irg(blk);

		/* skip a potential Pin */
		mem = skip_Pin(mem);
		turn_into_tuple(n, pn_Mod_max+1);
		set_Tuple_pred(n, pn_Mod_M,         mem);
		set_Tuple_pred(n, pn_Mod_X_regular, new_r_Jmp(blk));
		set_Tuple_pred(n, pn_Mod_X_except,  new_r_Bad(irg, mode_X));
		set_Tuple_pred(n, pn_Mod_res,       value);
	}
	return n;
}

/**
 * Transform a Cond node.
 *
 * Replace the Cond by a Jmp if it branches on a constant
 * condition.
 */
static ir_node *transform_node_Cond(ir_node *n)
{
	ir_node   *a   = get_Cond_selector(n);
	ir_graph  *irg = get_irn_irg(n);
	ir_tarval *ta;
	ir_node   *jmp;

	/* we need block info which is not available in floating irgs */
	if (get_irg_pinned(irg) == op_pin_state_floats)
		return n;

	ta = value_of(a);
	if (ta == tarval_bad && is_Cmp(a)) {
		/* try again with a direct call to compute_cmp, as we don't care
		 * about the MODEB_LOWERED flag here */
		ta = compute_cmp_ext(a);
	}

	if (ta != tarval_bad && get_irn_mode(a) == mode_b) {
		/* It's a boolean Cond, branching on a boolean constant.
		   Replace it by a tuple (Bad, Jmp) or (Jmp, Bad) */
		ir_node *blk = get_nodes_block(n);
		jmp = new_r_Jmp(blk);
		turn_into_tuple(n, pn_Cond_max+1);
		if (ta == tarval_b_true) {
			set_Tuple_pred(n, pn_Cond_false, new_r_Bad(irg, mode_X));
			set_Tuple_pred(n, pn_Cond_true, jmp);
		} else {
			set_Tuple_pred(n, pn_Cond_false, jmp);
			set_Tuple_pred(n, pn_Cond_true, new_r_Bad(irg, mode_X));
		}
		clear_irg_properties(irg, IR_GRAPH_PROPERTY_NO_UNREACHABLE_CODE);
	}
	return n;
}

static ir_node *transform_node_Switch(ir_node *n)
{
	ir_node   *op  = get_Switch_selector(n);
	ir_tarval *val = value_of(op);
	if (val != tarval_bad) {
		dbg_info              *dbgi      = get_irn_dbg_info(n);
		ir_graph              *irg       = get_irn_irg(n);
		unsigned               n_outs    = get_Switch_n_outs(n);
		ir_node               *block     = get_nodes_block(n);
		ir_node               *bad       = new_r_Bad(irg, mode_X);
		ir_node              **in        = XMALLOCN(ir_node*, n_outs);
		const ir_switch_table *table     = get_Switch_table(n);
		size_t                 n_entries = ir_switch_table_get_n_entries(table);
		long                   jmp_pn    = 0;
		size_t                 i;
		unsigned               o;
		for (i = 0; i < n_entries; ++i) {
			const ir_switch_table_entry *entry
				= ir_switch_table_get_entry_const(table, i);
			ir_tarval *min = entry->min;
			ir_tarval *max = entry->max;
			if (entry->pn == 0)
				continue;
			if ((min == max && min == val)
			    || (tarval_cmp(val, min) != ir_relation_less
			        && tarval_cmp(val, max) != ir_relation_greater)) {
			    jmp_pn = entry->pn;
			    break;
			}
		}
		for (o = 0; o < n_outs; ++o) {
			if (o == (unsigned)jmp_pn) {
				in[o] = new_rd_Jmp(dbgi, block);
			} else {
				in[o] = bad;
			}
		}
		return new_r_Tuple(block, (int)n_outs, in);
	}
	return n;
}

/**
 * normalisation: (x & c1) >> c2   to   (x >> c2) & (c1 >> c2)
 *  (we can use:
 *    - and, or, xor          instead of &
 *    - Shl, Shr, Shrs, rotl  instead of >>
 *    (with a special case for Or/Xor + Shrs)
 *
 * This normalisation is good for things like x-(x&y) esp. in 186.crafty.
 */
static ir_node *transform_node_shift_bitop(ir_node *n)
{
	ir_graph  *irg   = get_irn_irg(n);
	ir_node   *right = get_binop_right(n);
	ir_mode   *mode  = get_irn_mode(n);
	ir_node   *left;
	ir_node   *bitop_left;
	ir_node   *bitop_right;
	ir_op     *op_left;
	ir_node   *block;
	dbg_info  *dbgi;
	ir_node   *new_shift;
	ir_node   *new_bitop;
	ir_node   *new_const;
	ir_tarval *tv1;
	ir_tarval *tv2;
	ir_tarval *tv_shift;

	if (irg_is_constrained(irg, IR_GRAPH_CONSTRAINT_NORMALISATION2))
		return n;

	assert(is_Shrs(n) || is_Shr(n) || is_Shl(n) || is_Rotl(n));

	if (!is_Const(right))
		return n;

	left    = get_binop_left(n);
	op_left = get_irn_op(left);
	if (op_left != op_And && op_left != op_Or && op_left != op_Eor)
		return n;

	/* doing it with Shrs is not legal if the Or/Eor affects the topmost bit */
	if (is_Shrs(n) && (op_left == op_Or || op_left == op_Eor)) {
		/* TODO: test if sign bit is affectes */
		return n;
	}

	bitop_right = get_binop_right(left);
	if (!is_Const(bitop_right))
		return n;

	bitop_left = get_binop_left(left);

	block = get_nodes_block(n);
	dbgi  = get_irn_dbg_info(n);
	tv1   = get_Const_tarval(bitop_right);
	tv2   = get_Const_tarval(right);

	assert(get_tarval_mode(tv1) == mode);

	if (is_Shl(n)) {
		new_shift = new_rd_Shl(dbgi, block, bitop_left, right, mode);
		tv_shift  = tarval_shl(tv1, tv2);
	} else if (is_Shr(n)) {
		new_shift = new_rd_Shr(dbgi, block, bitop_left, right, mode);
		tv_shift  = tarval_shr(tv1, tv2);
	} else if (is_Shrs(n)) {
		new_shift = new_rd_Shrs(dbgi, block, bitop_left, right, mode);
		tv_shift  = tarval_shrs(tv1, tv2);
	} else {
		assert(is_Rotl(n));
		new_shift = new_rd_Rotl(dbgi, block, bitop_left, right, mode);
		tv_shift  = tarval_rotl(tv1, tv2);
	}

	assert(get_tarval_mode(tv_shift) == mode);
	irg       = get_irn_irg(n);
	new_const = new_r_Const(irg, tv_shift);

	if (op_left == op_And) {
		new_bitop = new_rd_And(dbgi, block, new_shift, new_const, mode);
	} else if (op_left == op_Or) {
		new_bitop = new_rd_Or(dbgi, block, new_shift, new_const, mode);
	} else {
		assert(op_left == op_Eor);
		new_bitop = new_rd_Eor(dbgi, block, new_shift, new_const, mode);
	}

	return new_bitop;
}

/**
 * Transform an And.
 */
static ir_node *transform_node_And(ir_node *n)
{
	ir_node *c, *oldn = n;
	ir_node *a = get_And_left(n);
	ir_node *b = get_And_right(n);
	ir_mode *mode;

	n = fold_constant_associativity(n, tarval_and);
	if (n != oldn)
		return n;

	if (is_Cmp(a) && is_Cmp(b)) {
		ir_node    *a_left     = get_Cmp_left(a);
		ir_node    *a_right    = get_Cmp_right(a);
		ir_node    *b_left     = get_Cmp_left(b);
		ir_node    *b_right    = get_Cmp_right(b);
		ir_relation a_relation = get_Cmp_relation(a);
		ir_relation b_relation = get_Cmp_relation(b);
		/* we can combine the relations of two compares with the same
		 * operands */
		if (a_left == b_left && b_left == b_right) {
			dbg_info   *dbgi         = get_irn_dbg_info(n);
			ir_node    *block        = get_nodes_block(n);
			ir_relation new_relation = a_relation & b_relation;
			return new_rd_Cmp(dbgi, block, a_left, a_right, new_relation);
		}
		/* Cmp(a==b) and Cmp(c==d) can be optimized to Cmp((a^b)|(c^d)==0) */
		if (a_relation == b_relation && a_relation == ir_relation_equal
		    && !mode_is_float(get_irn_mode(a_left))
		    && !mode_is_float(get_irn_mode(b_left))) {
			if (values_in_mode(get_irn_mode(a_left), get_irn_mode(b_left))) {
				dbg_info *dbgi   = get_irn_dbg_info(n);
				ir_node  *block  = get_nodes_block(n);
				ir_mode  *a_mode = get_irn_mode(a_left);
				ir_mode  *b_mode = get_irn_mode(b_left);
				ir_node  *xora   = new_rd_Eor(dbgi, block, a_left, a_right, a_mode);
				ir_node  *xorb   = new_rd_Eor(dbgi, block, b_left, b_right, b_mode);
				ir_node  *conv   = new_rd_Conv(dbgi, block, xora, b_mode);
				ir_node  *orn    = new_rd_Or(dbgi, block, conv, xorb, b_mode);
				ir_graph *irg    = get_irn_irg(n);
				ir_node  *zero   = create_zero_const(irg, b_mode);
				return new_rd_Cmp(dbgi, block, orn, zero, ir_relation_equal);
			}
			if (values_in_mode(get_irn_mode(b_left), get_irn_mode(a_left))) {
				dbg_info *dbgi   = get_irn_dbg_info(n);
				ir_node  *block  = get_nodes_block(n);
				ir_mode  *a_mode = get_irn_mode(a_left);
				ir_mode  *b_mode = get_irn_mode(b_left);
				ir_node  *xora   = new_rd_Eor(dbgi, block, a_left, a_right, a_mode);
				ir_node  *xorb   = new_rd_Eor(dbgi, block, b_left, b_right, b_mode);
				ir_node  *conv   = new_rd_Conv(dbgi, block, xorb, a_mode);
				ir_node  *orn    = new_rd_Or(dbgi, block, xora, conv, a_mode);
				ir_graph *irg    = get_irn_irg(n);
				ir_node  *zero   = create_zero_const(irg, a_mode);
				return new_rd_Cmp(dbgi, block, orn, zero, ir_relation_equal);
			}
		}
	}

	mode = get_irn_mode(n);
	HANDLE_BINOP_PHI((eval_func) tarval_and, a, b, c, mode);

	if (is_Or(a) || is_Or_Eor_Add(a)) {
		ir_node *or_left  = get_binop_left(a);
		ir_node *or_right = get_binop_right(a);
		if (complement_values(or_left, b)) {
			/* (a|b) & ~a => b & ~a */
			dbg_info *dbgi    = get_irn_dbg_info(n);
			ir_node  *block   = get_nodes_block(n);
			return new_rd_And(dbgi, block, or_right, b, mode);
		} else if (complement_values(or_right, b)) {
			/* (a|b) & ~b => a & ~b */
			dbg_info *dbgi    = get_irn_dbg_info(n);
			ir_node  *block   = get_nodes_block(n);
			return new_rd_And(dbgi, block, or_left, b, mode);
		} else if (is_Not(b)) {
			ir_node *op = get_Not_op(b);
			if (is_And(op)) {
				ir_node *ba = get_And_left(op);
				ir_node *bb = get_And_right(op);

				/* it's enough to test the following cases due to normalization! */
				if (or_left == ba && or_right == bb) {
					/* (a|b) & ~(a&b) = a^b */
					ir_node *block = get_nodes_block(n);

					n = new_rd_Eor(get_irn_dbg_info(n), block, ba, bb, mode);
					DBG_OPT_ALGSIM1(oldn, a, b, n, FS_OPT_TO_EOR);
					return n;
				}
			}
		}
	}
	if (is_Or(b) || is_Or_Eor_Add(b)) {
		ir_node *or_left  = get_binop_left(b);
		ir_node *or_right = get_binop_right(b);
		if (complement_values(or_left, a)) {
			/* (a|b) & ~a => b & ~a */
			dbg_info *dbgi    = get_irn_dbg_info(n);
			ir_node  *block   = get_nodes_block(n);
			return new_rd_And(dbgi, block, or_right, a, mode);
		} else if (complement_values(or_right, a)) {
			/* (a|b) & ~b => a & ~b */
			dbg_info *dbgi    = get_irn_dbg_info(n);
			ir_node  *block   = get_nodes_block(n);
			return new_rd_And(dbgi, block, or_left, a, mode);
		} else if (is_Not(a)) {
			ir_node *op = get_Not_op(a);
			if (is_And(op)) {
				ir_node *aa = get_And_left(op);
				ir_node *ab = get_And_right(op);

				/* it's enough to test the following cases due to normalization! */
				if (or_left == aa && or_right == ab) {
					/* (a|b) & ~(a&b) = a^b */
					ir_node *block = get_nodes_block(n);

					n = new_rd_Eor(get_irn_dbg_info(n), block, aa, ab, mode);
					DBG_OPT_ALGSIM1(oldn, a, b, n, FS_OPT_TO_EOR);
					return n;
				}
			}
		}
	}
	if (is_Eor(a) || is_Or_Eor_Add(a)) {
		ir_node *al = get_binop_left(a);
		ir_node *ar = get_binop_right(a);

		if (al == b) {
			/* (b ^ a) & b -> ~a & b */
			dbg_info *dbg  = get_irn_dbg_info(n);
			ir_node *block = get_nodes_block(n);

			ar = new_rd_Not(dbg, block, ar, mode);
			n  = new_rd_And(dbg, block, ar, b, mode);
			DBG_OPT_ALGSIM0(oldn, n, FS_OPT_EOR_TO_NOT);
			return n;
		}
		if (ar == b) {
			/* (a ^ b) & b -> ~a & b */
			dbg_info *dbg  = get_irn_dbg_info(n);
			ir_node *block = get_nodes_block(n);

			al = new_rd_Not(dbg, block, al, mode);
			n  = new_rd_And(dbg, block, al, b, mode);
			DBG_OPT_ALGSIM0(oldn, n, FS_OPT_EOR_TO_NOT);
			return n;
		}
	}
	if (is_Eor(b) || is_Or_Eor_Add(b)) {
		ir_node *bl = get_binop_left(b);
		ir_node *br = get_binop_right(b);

		if (bl == a) {
			/* a & (a ^ b) -> a & ~b */
			dbg_info *dbg  = get_irn_dbg_info(n);
			ir_node *block = get_nodes_block(n);

			br = new_rd_Not(dbg, block, br, mode);
			n  = new_rd_And(dbg, block, br, a, mode);
			DBG_OPT_ALGSIM0(oldn, n, FS_OPT_EOR_TO_NOT);
			return n;
		}
		if (br == a) {
			/* a & (b ^ a) -> a & ~b */
			dbg_info *dbg  = get_irn_dbg_info(n);
			ir_node *block = get_nodes_block(n);

			bl = new_rd_Not(dbg, block, bl, mode);
			n  = new_rd_And(dbg, block, bl, a, mode);
			DBG_OPT_ALGSIM0(oldn, n, FS_OPT_EOR_TO_NOT);
			return n;
		}
	}
	if (is_Not(a) && is_Not(b)) {
		/* ~a & ~b = ~(a|b) */
		ir_node *block = get_nodes_block(n);
		ir_mode *mode = get_irn_mode(n);

		a = get_Not_op(a);
		b = get_Not_op(b);
		n = new_rd_Or(get_irn_dbg_info(n), block, a, b, mode);
		n = new_rd_Not(get_irn_dbg_info(n), block, n, mode);
		DBG_OPT_ALGSIM0(oldn, n, FS_OPT_DEMORGAN);
		return n;
	}

	if (is_Const(a)) {
		vrp_attr  *b_vrp = vrp_get_info(b);
		ir_tarval *a_val = get_Const_tarval(a);
		if (b_vrp != NULL && tarval_or(a_val, b_vrp->bits_not_set) == a_val) {
			return b;
		}
	}

	if (is_Const(b)) {
		vrp_attr  *a_vrp = vrp_get_info(a);
		ir_tarval *b_val = get_Const_tarval(b);
		if (a_vrp != NULL && tarval_or(b_val, a_vrp->bits_not_set) == b_val) {
			return a;
		}
	}

	n = transform_bitwise_distributive(n, transform_node_And);
	if (is_And(n))
		n = transform_node_bitop_shift(n);

	return n;
}

/**
 * Transform a Not.
 */
static ir_node *transform_node_Not(ir_node *n)
{
	ir_node *c, *oldn = n;
	ir_node *a    = get_Not_op(n);
	ir_mode *mode = get_irn_mode(n);

	HANDLE_UNOP_PHI(tarval_not,a,c);

	/* check for a boolean Not */
	if (is_Cmp(a)) {
		dbg_info *dbgi  = get_irn_dbg_info(a);
		ir_node  *block = get_nodes_block(a);
		ir_relation relation = get_Cmp_relation(a);
		relation = get_negated_relation(relation);
		n = new_rd_Cmp(dbgi, block, get_Cmp_left(a), get_Cmp_right(a), relation);
		DBG_OPT_ALGSIM0(oldn, n, FS_OPT_NOT_CMP);
		return n;
	}

	/* normalize ~(a ^ b) => a ^ ~b */
	if (is_Eor(a) || is_Or_Eor_Add(a)) {
		dbg_info *dbg       = get_irn_dbg_info(n);
		ir_node  *block     = get_nodes_block(n);
		ir_node  *eor_right = get_binop_right(a);
		ir_node  *eor_left  = get_binop_left(a);
		eor_right = new_rd_Not(dbg, block, eor_right, mode);
		n = new_rd_Eor(dbg, block, eor_left, eor_right, mode);
		return n;
	}

	if (get_mode_arithmetic(mode) == irma_twos_complement) {
		if (is_Minus(a)) { /* ~-x -> x + -1 */
			dbg_info *dbg   = get_irn_dbg_info(n);
			ir_graph *irg   = get_irn_irg(n);
			ir_node  *block = get_nodes_block(n);
			ir_node  *add_l = get_Minus_op(a);
			ir_node  *add_r = new_rd_Const(dbg, irg, get_mode_minus_one(mode));
			n = new_rd_Add(dbg, block, add_l, add_r, mode);
		} else if (is_Add(a) || is_Or_Eor_Add(a)) {
			ir_node *add_r = get_binop_right(a);
			if (is_Const(add_r) && is_Const_all_one(add_r)) {
				/* ~(x + -1) = -x */
				ir_node *op  = get_binop_left(a);
				ir_node *blk = get_nodes_block(n);
				n = new_rd_Minus(get_irn_dbg_info(n), blk, op, get_irn_mode(n));
				DBG_OPT_ALGSIM0(oldn, n, FS_OPT_NOT_MINUS_1);
			}
		}
	}
	return n;
}

/**
 * Transform a Minus.
 * Optimize:
 *   -(~x) = x + 1
 *   -(a-b) = b - a
 *   -(a >>u (size-1)) = a >>s (size-1)
 *   -(a >>s (size-1)) = a >>u (size-1)
 *   -(a * const) -> a * -const
 */
static ir_node *transform_node_Minus(ir_node *n)
{
	ir_node *c, *oldn = n;
	ir_node *a = get_Minus_op(n);
	ir_mode *mode;

	HANDLE_UNOP_PHI(tarval_neg,a,c);

	mode = get_irn_mode(a);
	if (get_mode_arithmetic(mode) == irma_twos_complement) {
		/* the following rules are only to twos-complement */
		if (is_Not(a)) {
			/* -(~x) = x + 1 */
			ir_node   *op  = get_Not_op(a);
			ir_tarval *tv  = get_mode_one(mode);
			ir_node   *blk = get_nodes_block(n);
			ir_graph  *irg = get_irn_irg(blk);
			ir_node   *c   = new_r_Const(irg, tv);
			n = new_rd_Add(get_irn_dbg_info(n), blk, op, c, mode);
			DBG_OPT_ALGSIM2(oldn, a, n, FS_OPT_MINUS_NOT);
			return n;
		}
		if (is_Shr(a)) {
			ir_node *c = get_Shr_right(a);

			if (is_Const(c)) {
				ir_tarval *tv = get_Const_tarval(c);

				if (tarval_is_long(tv) && get_tarval_long(tv) == (int) get_mode_size_bits(mode) - 1) {
					/* -(a >>u (size-1)) = a >>s (size-1) */
					ir_node *v = get_Shr_left(a);

					n = new_rd_Shrs(get_irn_dbg_info(n), get_nodes_block(n), v, c, mode);
					DBG_OPT_ALGSIM2(oldn, a, n, FS_OPT_PREDICATE);
					return n;
				}
			}
		}
		if (is_Shrs(a)) {
			ir_node *c = get_Shrs_right(a);

			if (is_Const(c)) {
				ir_tarval *tv = get_Const_tarval(c);

				if (tarval_is_long(tv) && get_tarval_long(tv) == (int) get_mode_size_bits(mode) - 1) {
					/* -(a >>s (size-1)) = a >>u (size-1) */
					ir_node *v = get_Shrs_left(a);

					n = new_rd_Shr(get_irn_dbg_info(n), get_nodes_block(n), v, c, mode);
					DBG_OPT_ALGSIM2(oldn, a, n, FS_OPT_PREDICATE);
					return n;
				}
			}
		}
	}
	if (is_Sub(a)) {
		/* - (a-b) = b - a */
		ir_node *la  = get_Sub_left(a);
		ir_node *ra  = get_Sub_right(a);
		ir_node *blk = get_nodes_block(n);

		n = new_rd_Sub(get_irn_dbg_info(n), blk, ra, la, mode);
		DBG_OPT_ALGSIM2(oldn, a, n, FS_OPT_MINUS_SUB);
		return n;
	}

	if (is_Mul(a)) { /* -(a * const) -> a * -const */
		ir_node   *mul_l = get_Mul_left(a);
		ir_node   *mul_r = get_Mul_right(a);
		ir_tarval *tv    = value_of(mul_r);
		if (tv != tarval_bad) {
			tv = tarval_neg(tv);
			if (tv != tarval_bad) {
				ir_graph *irg   = get_irn_irg(n);
				ir_node  *cnst  = new_r_Const(irg, tv);
				dbg_info *dbg   = get_irn_dbg_info(a);
				ir_node  *block = get_nodes_block(a);
				n = new_rd_Mul(dbg, block, mul_l, cnst, mode);
				DBG_OPT_ALGSIM2(oldn, a, n, FS_OPT_MINUS_MUL_C);
				return n;
			}
		}
	}

	return n;
}

/**
 * Transform a Proj(Load) with a non-null address.
 */
static ir_node *transform_node_Proj_Load(ir_node *proj)
{
	if (get_irn_mode(proj) == mode_X) {
		ir_node *load = get_Proj_pred(proj);

		/* get the Load address */
		const ir_node *addr = get_Load_ptr(load);
		const ir_node *confirm;

		if (value_not_null(addr, &confirm)) {
			if (confirm == NULL) {
				/* this node may float if it did not depend on a Confirm */
				set_irn_pinned(load, op_pin_state_floats);
			}
			if (get_Proj_proj(proj) == pn_Load_X_except) {
				ir_graph *irg = get_irn_irg(proj);
				DBG_OPT_EXC_REM(proj);
				return new_r_Bad(irg, mode_X);
			} else {
				ir_node *blk = get_nodes_block(load);
				return new_r_Jmp(blk);
			}
		}
	}
	return proj;
}

/**
 * Transform a Proj(Store) with a non-null address.
 */
static ir_node *transform_node_Proj_Store(ir_node *proj)
{
	if (get_irn_mode(proj) == mode_X) {
		ir_node *store = get_Proj_pred(proj);

		/* get the load/store address */
		const ir_node *addr = get_Store_ptr(store);
		const ir_node *confirm;

		if (value_not_null(addr, &confirm)) {
			if (confirm == NULL) {
				/* this node may float if it did not depend on a Confirm */
				set_irn_pinned(store, op_pin_state_floats);
			}
			if (get_Proj_proj(proj) == pn_Store_X_except) {
				ir_graph *irg = get_irn_irg(proj);
				DBG_OPT_EXC_REM(proj);
				return new_r_Bad(irg, mode_X);
			} else {
				ir_node *blk = get_nodes_block(store);
				return new_r_Jmp(blk);
			}
		}
	}
	return proj;
}

/**
 * Transform a Proj(Div) with a non-zero value.
 * Removes the exceptions and routes the memory to the NoMem node.
 */
static ir_node *transform_node_Proj_Div(ir_node *proj)
{
	ir_node *div = get_Proj_pred(proj);
	ir_node *b   = get_Div_right(div);
	ir_node *res, *new_mem;
	const ir_node *confirm;
	long proj_nr;

	if (value_not_zero(b, &confirm)) {
		/* div(x, y) && y != 0 */
		if (confirm == NULL) {
			/* we are sure we have a Const != 0 */
			new_mem = get_Div_mem(div);
			new_mem = skip_Pin(new_mem);
			set_Div_mem(div, new_mem);
			set_irn_pinned(div, op_pin_state_floats);
		}

		proj_nr = get_Proj_proj(proj);
		switch (proj_nr) {
		case pn_Div_X_regular:
			return new_r_Jmp(get_nodes_block(div));

		case pn_Div_X_except: {
			ir_graph *irg = get_irn_irg(proj);
			/* we found an exception handler, remove it */
			DBG_OPT_EXC_REM(proj);
			return new_r_Bad(irg, mode_X);
		}

		case pn_Div_M: {
			ir_graph *irg = get_irn_irg(proj);
			res = get_Div_mem(div);
			new_mem = get_irg_no_mem(irg);

			if (confirm) {
				/* This node can only float up to the Confirm block */
				new_mem = new_r_Pin(get_nodes_block(confirm), new_mem);
			}
			set_irn_pinned(div, op_pin_state_floats);
			/* this is a Div without exception, we can remove the memory edge */
			set_Div_mem(div, new_mem);
			return res;
		}
		}
	}
	return proj;
}

/**
 * Transform a Proj(Mod) with a non-zero value.
 * Removes the exceptions and routes the memory to the NoMem node.
 */
static ir_node *transform_node_Proj_Mod(ir_node *proj)
{
	ir_node *mod = get_Proj_pred(proj);
	ir_node *b   = get_Mod_right(mod);
	ir_node *res, *new_mem;
	const ir_node *confirm;
	long proj_nr;

	if (value_not_zero(b, &confirm)) {
		/* mod(x, y) && y != 0 */
		proj_nr = get_Proj_proj(proj);

		if (confirm == NULL) {
			/* we are sure we have a Const != 0 */
			new_mem = get_Mod_mem(mod);
			new_mem = skip_Pin(new_mem);
			set_Mod_mem(mod, new_mem);
			set_irn_pinned(mod, op_pin_state_floats);
		}

		switch (proj_nr) {

		case pn_Mod_X_regular:
			return new_r_Jmp(get_nodes_block(mod));

		case pn_Mod_X_except: {
			ir_graph *irg = get_irn_irg(proj);
			/* we found an exception handler, remove it */
			DBG_OPT_EXC_REM(proj);
			return new_r_Bad(irg, mode_X);
		}

		case pn_Mod_M: {
			ir_graph *irg = get_irn_irg(proj);
			res = get_Mod_mem(mod);
			new_mem = get_irg_no_mem(irg);

			if (confirm) {
				/* This node can only float up to the Confirm block */
				new_mem = new_r_Pin(get_nodes_block(confirm), new_mem);
			}
			/* this is a Mod without exception, we can remove the memory edge */
			set_Mod_mem(mod, new_mem);
			return res;
		}
		case pn_Mod_res:
			if (get_Mod_left(mod) == b) {
				/* a % a = 0 if a != 0 */
				ir_graph *irg  = get_irn_irg(proj);
				ir_mode  *mode = get_irn_mode(proj);
				ir_node  *res  = new_r_Const(irg, get_mode_null(mode));

				DBG_OPT_CSTEVAL(mod, res);
				return res;
			}
		}
	}
	return proj;
}

/**
 * return true if the operation returns a value with exactly 1 bit set
 */
static bool is_single_bit(const ir_node *node)
{
	/* a first implementation, could be extended with vrp and others... */
	if (is_Shl(node)) {
		ir_node *shl_l  = get_Shl_left(node);
		ir_mode *mode   = get_irn_mode(node);
		int      modulo = get_mode_modulo_shift(mode);
		/* this works if we shift a 1 and we have modulo shift */
		if (is_Const(shl_l) && is_Const_one(shl_l)
				&& 0 < modulo && modulo <= (int)get_mode_size_bits(mode)) {
			return true;
		}
	} else if (is_Const(node)) {
		ir_tarval *tv = get_Const_tarval(node);
		return tarval_is_single_bit(tv);
	}
	return false;
}

/**
 * checks if node just flips a bit in another node and returns that other node
 * if so. @p tv should be a value having just 1 bit set
 */
static ir_node *flips_bit(const ir_node *node, ir_tarval *tv)
{
	if (is_Not(node))
		return get_Not_op(node);
	if (is_Eor(node)) {
		ir_node *right = get_Eor_right(node);
		if (is_Const(right)) {
			ir_tarval *right_tv = get_Const_tarval(right);
			ir_mode   *mode     = get_irn_mode(node);
			if (tarval_and(right_tv, tv) != get_mode_null(mode))
				return get_Eor_left(node);
		}
	}
	return NULL;
}

/**
 * Normalizes and optimizes Cmp nodes.
 */
static ir_node *transform_node_Cmp(ir_node *n)
{
	ir_node    *left     = get_Cmp_left(n);
	ir_node    *right    = get_Cmp_right(n);
	ir_mode    *mode     = get_irn_mode(left);
	ir_tarval  *tv       = NULL;
	bool        changed  = false;
	bool        changedc = false;
	ir_relation relation = get_Cmp_relation(n);
	ir_relation possible = ir_get_possible_cmp_relations(left, right);

	/* mask out impossible relations */
	ir_relation new_relation = relation & possible;
	if (new_relation != relation) {
		relation = new_relation;
		changed  = true;
	}

	/* Remove unnecessary conversions */
	if (!mode_is_float(mode)
	    || be_get_backend_param()->mode_float_arithmetic == NULL) {
		if (is_Conv(left) && is_Conv(right)) {
			ir_node *op_left    = get_Conv_op(left);
			ir_node *op_right   = get_Conv_op(right);
			ir_mode *mode_left  = get_irn_mode(op_left);
			ir_mode *mode_right = get_irn_mode(op_right);

			if (smaller_mode(mode_left, mode) && smaller_mode(mode_right, mode)
					&& mode_left != mode_b && mode_right != mode_b) {
				ir_node *block = get_nodes_block(n);

				if (mode_left == mode_right) {
					left    = op_left;
					right   = op_right;
					changed = true;
					DBG_OPT_ALGSIM0(n, n, FS_OPT_CMP_CONV_CONV);
				} else if (smaller_mode(mode_left, mode_right)) {
					left    = new_r_Conv(block, op_left, mode_right);
					right   = op_right;
					changed = true;
					DBG_OPT_ALGSIM0(n, n, FS_OPT_CMP_CONV);
				} else if (smaller_mode(mode_right, mode_left)) {
					left    = op_left;
					right   = new_r_Conv(block, op_right, mode_left);
					changed = true;
					DBG_OPT_ALGSIM0(n, n, FS_OPT_CMP_CONV);
				}
				mode = get_irn_mode(left);
			}
		}
		if (is_Conv(left) && is_Const(right)) {
			ir_node   *op_left   = get_Conv_op(left);
			ir_mode   *mode_left = get_irn_mode(op_left);
			if (smaller_mode(mode_left, mode) && mode_left != mode_b) {
				ir_tarval *tv        = get_Const_tarval(right);
				tarval_int_overflow_mode_t last_mode
					= tarval_get_integer_overflow_mode();
				ir_tarval *new_tv;
				tarval_set_integer_overflow_mode(TV_OVERFLOW_BAD);
				new_tv = tarval_convert_to(tv, mode_left);
				tarval_set_integer_overflow_mode(last_mode);
				if (new_tv != tarval_bad) {
					ir_graph *irg = get_irn_irg(n);
					left    = op_left;
					right   = new_r_Const(irg, new_tv);
					mode    = get_irn_mode(left);
					changed = true;
					DBG_OPT_ALGSIM0(n, n, FS_OPT_CMP_CONV);
				}
			}
		}
	}

	/*
	 * Optimize -a CMP -b into b CMP a.
	 * This works only for modes where unary Minus cannot Overflow.
	 * Note that two-complement integers can Overflow so it will NOT work.
	 */
	if (!mode_overflow_on_unary_Minus(mode) &&
			is_Minus(left) && is_Minus(right)) {
		left     = get_Minus_op(left);
		right    = get_Minus_op(right);
		relation = get_inversed_relation(relation);
		changed  = true;
		DBG_OPT_ALGSIM0(n, n, FS_OPT_CMP_OP_OP);
	}

	/* remove operation on both sides if possible */
	if (relation == ir_relation_equal || relation == ir_relation_less_greater) {
		/*
		 * The following operations are NOT safe for floating point operations, for instance
		 * 1.0 + inf == 2.0 + inf, =/=> x == y
		 */
		if (mode_is_int(mode)) {
			unsigned lop = get_irn_opcode(left);

			if (lop == get_irn_opcode(right)) {
				ir_node *ll, *lr, *rl, *rr;

				/* same operation on both sides, try to remove */
				switch (lop) {
				case iro_Not:
				case iro_Minus:
					/* ~a CMP ~b => a CMP b, -a CMP -b ==> a CMP b */
					left  = get_unop_op(left);
					right = get_unop_op(right);
					changed = true;
					DBG_OPT_ALGSIM0(n, n, FS_OPT_CMP_OP_OP);
					break;
				case iro_Add:
					ll = get_Add_left(left);
					lr = get_Add_right(left);
					rl = get_Add_left(right);
					rr = get_Add_right(right);

					if (ll == rl) {
						/* X + a CMP X + b ==> a CMP b */
						left  = lr;
						right = rr;
						changed = true;
						DBG_OPT_ALGSIM0(n, n, FS_OPT_CMP_OP_OP);
					} else if (ll == rr) {
						/* X + a CMP b + X ==> a CMP b */
						left  = lr;
						right = rl;
						changed = true;
						DBG_OPT_ALGSIM0(n, n, FS_OPT_CMP_OP_OP);
					} else if (lr == rl) {
						/* a + X CMP X + b ==> a CMP b */
						left  = ll;
						right = rr;
						changed = true;
						DBG_OPT_ALGSIM0(n, n, FS_OPT_CMP_OP_OP);
					} else if (lr == rr) {
						/* a + X CMP b + X ==> a CMP b */
						left  = ll;
						right = rl;
						changed = true;
						DBG_OPT_ALGSIM0(n, n, FS_OPT_CMP_OP_OP);
					}
					break;
				case iro_Sub:
					ll = get_Sub_left(left);
					lr = get_Sub_right(left);
					rl = get_Sub_left(right);
					rr = get_Sub_right(right);

					if (ll == rl) {
						/* X - a CMP X - b ==> a CMP b */
						left  = lr;
						right = rr;
						changed = true;
						DBG_OPT_ALGSIM0(n, n, FS_OPT_CMP_OP_OP);
					} else if (lr == rr) {
						/* a - X CMP b - X ==> a CMP b */
						left  = ll;
						right = rl;
						changed = true;
						DBG_OPT_ALGSIM0(n, n, FS_OPT_CMP_OP_OP);
					}
					break;
				case iro_Rotl:
					if (get_Rotl_right(left) == get_Rotl_right(right)) {
						/* a ROTL X CMP b ROTL X ==> a CMP b */
						left  = get_Rotl_left(left);
						right = get_Rotl_left(right);
						changed = true;
						DBG_OPT_ALGSIM0(n, n, FS_OPT_CMP_OP_OP);
					}
					break;
				default:
					break;
				}
			}

			/* X+A == A, A+X == A, A-X == A -> X == 0 */
			if (is_Add(left) || is_Sub(left) || is_Or_Eor_Add(left)) {
				ir_node *ll = get_binop_left(left);
				ir_node *lr = get_binop_right(left);

				if (lr == right && (is_Add(left) || is_Or_Eor_Add(left))) {
					ir_node *tmp = ll;
					ll = lr;
					lr = tmp;
				}
				if (ll == right) {
					ir_graph *irg = get_irn_irg(n);
					left     = lr;
					right   = create_zero_const(irg, mode);
					changed = true;
					DBG_OPT_ALGSIM0(n, n, FS_OPT_CMP_OP_OP);
				}
			}
			if (is_Add(right) || is_Sub(right) || is_Or_Eor_Add(right)) {
				ir_node *rl = get_binop_left(right);
				ir_node *rr = get_binop_right(right);

				if (rr == left && (is_Add(right) || is_Or_Eor_Add(right))) {
					ir_node *tmp = rl;
					rl = rr;
					rr = tmp;
				}
				if (rl == left) {
					ir_graph *irg = get_irn_irg(n);
					left     = rr;
					right   = create_zero_const(irg, mode);
					changed = true;
					DBG_OPT_ALGSIM0(n, n, FS_OPT_CMP_OP_OP);
				}
			}

			if (is_And(left) && is_Const(right)) {
				ir_node *ll = get_binop_left(left);
				ir_node *lr = get_binop_right(left);
				if (is_Shr(ll) && is_Const(lr)) {
					/* Cmp((x >>u c1) & c2, c3) = Cmp(x & (c2 << c1), c3 << c1) */
					ir_node *block = get_nodes_block(n);
					ir_mode *mode = get_irn_mode(left);

					ir_node *llr = get_Shr_right(ll);
					if (is_Const(llr)) {
						dbg_info *dbg = get_irn_dbg_info(left);
						ir_graph *irg = get_irn_irg(left);

						ir_tarval *c1    = get_Const_tarval(llr);
						ir_tarval *c2    = get_Const_tarval(lr);
						ir_tarval *c3    = get_Const_tarval(right);
						ir_tarval *mask  = tarval_shl(c2, c1);
						ir_tarval *value = tarval_shl(c3, c1);

						left  = new_rd_And(dbg, block, get_Shr_left(ll), new_r_Const(irg, mask), mode);
						right = new_r_Const(irg, value);
						changed = true;
					}
				}
			}
			/* Cmp(Eor(x, y), 0) <=> Cmp(x, y) at least for the ==0,!=0
			 * cases */
			if (is_Const(right) && is_Const_null(right) &&
			    (is_Eor(left) || is_Or_Eor_Add(left))) {
				right = get_Eor_right(left);
				left  = get_Eor_left(left);
				changed = true;
			}
		}
	}

	if (mode_is_int(mode) && is_And(left)) {
		/* a complicated Cmp(And(1bit, val), 1bit) "bit-testing" can be replaced
		 * by the simpler Cmp(And(1bit, val), 0) negated pnc */
		if (relation == ir_relation_equal
	        || (mode_is_signed(mode) && relation == ir_relation_less_greater)
	        || (!mode_is_signed(mode) && (relation & ir_relation_less_equal) == ir_relation_less)) {
			ir_node *and0 = get_And_left(left);
			ir_node *and1 = get_And_right(left);
			if (and1 == right) {
				ir_node *tmp = and0;
				and0 = and1;
				and1 = tmp;
			}
			if (and0 == right && is_single_bit(and0)) {
				ir_graph *irg = get_irn_irg(n);
				relation =
					relation == ir_relation_equal ? ir_relation_less_greater
					                              : ir_relation_equal;
				right = create_zero_const(irg, mode);
				changed |= 1;
				goto is_bittest;
			}
		}

		if (is_Const(right) && is_Const_null(right) &&
		    (relation == ir_relation_equal
		    || (relation == ir_relation_less_greater)
		    || (!mode_is_signed(mode) && relation == ir_relation_greater))) {
is_bittest: {
			/* instead of flipping the bit before the bit-test operation negate
			 * pnc */
			ir_node *and0 = get_And_left(left);
			ir_node *and1 = get_And_right(left);
			if (is_Const(and1)) {
				ir_tarval *tv = get_Const_tarval(and1);
				if (tarval_is_single_bit(tv)) {
					ir_node *flipped = flips_bit(and0, tv);
					if (flipped != NULL) {
						dbg_info *dbgi  = get_irn_dbg_info(left);
						ir_node  *block = get_nodes_block(left);
						relation = get_negated_relation(relation);
						left = new_rd_And(dbgi, block, flipped, and1, mode);
						changed |= 1;
					}
				}
			}
			}
		}
	}

	/* replace mode_b compares with ands/ors */
	if (mode == mode_b) {
		ir_node  *block = get_nodes_block(n);
		ir_node  *bres;

		switch (relation) {
			case ir_relation_less_equal:
				bres = new_r_Or(block, new_r_Not(block, left, mode_b), right, mode_b);
				break;
			case ir_relation_less:
				bres = new_r_And(block, new_r_Not(block, left, mode_b), right, mode_b);
				break;
			case ir_relation_greater_equal:
				bres = new_r_Or(block, left, new_r_Not(block, right, mode_b), mode_b);
				break;
			case ir_relation_greater:
				bres = new_r_And(block, left, new_r_Not(block, right, mode_b), mode_b);
				break;
			case ir_relation_less_greater:
				bres = new_r_Eor(block, left, right, mode_b);
				break;
			case ir_relation_equal:
				bres = new_r_Not(block, new_r_Eor(block, left, right, mode_b), mode_b);
				break;
			default:
#ifdef DEBUG_libfirm
				ir_fprintf(stderr, "Optimisation warning, unexpected mode_b Cmp %+F\n", n);
#endif
				bres = NULL;
		}
		if (bres != NULL) {
			DBG_OPT_ALGSIM0(n, bres, FS_OPT_CMP_TO_BOOL);
			return bres;
		}
	}

	/*
	 * First step: normalize the compare op
	 * by placing the constant on the right side
	 * or moving the lower address node to the left.
	 */
	if (!operands_are_normalized(left, right)) {
		ir_node *t = left;
		left  = right;
		right = t;

		relation = get_inversed_relation(relation);
		changed  = true;
	}

	/*
	 * Second step: Try to reduce the magnitude
	 * of a constant. This may help to generate better code
	 * later and may help to normalize more compares.
	 * Of course this is only possible for integer values.
	 */
	tv = value_of(right);
	if (tv != tarval_bad) {
		ir_mode *mode = get_irn_mode(right);

		/* cmp(mux(x, cf, ct), c2) can be eliminated:
		 *   cmp(ct,c2) | cmp(cf,c2) | result
		 *   -----------|------------|--------
		 *   true       | true       | True
		 *   false      | false      | False
		 *   true       | false      | x
		 *   false      | true       | not(x)
		 */
		if (is_Mux(left)) {
			ir_node *mux_true  = get_Mux_true(left);
			ir_node *mux_false = get_Mux_false(left);
			if (is_Const(mux_true) && is_Const(mux_false)) {
				/* we can fold true/false constant separately */
				ir_tarval *tv_true  = get_Const_tarval(mux_true);
				ir_tarval *tv_false = get_Const_tarval(mux_false);
				ir_relation r_true  = tarval_cmp(tv_true, tv);
				ir_relation r_false = tarval_cmp(tv_false, tv);
				if (r_true != ir_relation_false
				    || r_false != ir_relation_false) {
					bool rel_true  = (r_true & relation)  != 0;
					bool rel_false = (r_false & relation) != 0;
					ir_node *cond = get_Mux_sel(left);
					if (rel_true == rel_false) {
						relation = rel_true ? ir_relation_true
						                    : ir_relation_false;
					} else if (rel_true) {
						return cond;
					} else {
						dbg_info *dbgi  = get_irn_dbg_info(n);
						ir_node  *block = get_nodes_block(n);
						ir_node  *notn  = new_rd_Not(dbgi, block, cond, mode_b);
						return notn;
					}
				}
			}
		}

		/* TODO extend to arbitrary constants */
		if (is_Conv(left) && tarval_is_null(tv)) {
			ir_node *op      = get_Conv_op(left);
			ir_mode *op_mode = get_irn_mode(op);

			/*
			 * UpConv(x) REL 0  ==> x REL 0
			 * Don't do this for float values as it's unclear whether it is a
			 * win. (on the other side it makes detection/creation of fabs hard)
			 */
			if (get_mode_size_bits(mode) > get_mode_size_bits(op_mode) &&
			    ((relation == ir_relation_equal || relation == ir_relation_less_greater) ||
				 mode_is_signed(mode) || !mode_is_signed(op_mode)) &&
				!mode_is_float(mode)) {
				tv   = get_mode_null(op_mode);
				left = op;
				mode = op_mode;
				changedc = true;
				DBG_OPT_ALGSIM0(n, n, FS_OPT_CMP_CONV);
			}
		}

		if (tv != tarval_bad) {
			/* the following optimization is possible on modes without Overflow
			 * on Unary Minus or on == and !=:
			 * -a CMP c  ==>  a swap(CMP) -c
			 *
			 * Beware: for two-complement Overflow may occur, so only == and != can
			 * be optimized, see this:
			 * -MININT < 0 =/=> MININT > 0 !!!
			 */
			if (is_Minus(left) &&
				(!mode_overflow_on_unary_Minus(mode) ||
				(mode_is_int(mode) && (relation == ir_relation_equal || relation == ir_relation_less_greater)))) {
				tv = tarval_neg(tv);

				if (tv != tarval_bad) {
					left = get_Minus_op(left);
					relation = get_inversed_relation(relation);
					changedc = true;
					DBG_OPT_ALGSIM0(n, n, FS_OPT_CMP_OP_C);
				}
			} else if (is_Not(left) && (relation == ir_relation_equal || relation == ir_relation_less_greater)) {
				/* Not(a) ==/!= c  ==>  a ==/!= Not(c) */
				tv = tarval_not(tv);

				if (tv != tarval_bad) {
					left = get_Not_op(left);
					changedc = true;
					DBG_OPT_ALGSIM0(n, n, FS_OPT_CMP_OP_C);
				}
			}

			/* for integer modes, we have more */
			if (mode_is_int(mode) && !is_Const(left)) {
				/* c > 0 : a < c  ==>  a <= (c-1)    a >= c  ==>  a > (c-1) */
				if ((relation == ir_relation_less || relation == ir_relation_greater_equal) &&
					tarval_cmp(tv, get_mode_null(mode)) == ir_relation_greater) {
					tv = tarval_sub(tv, get_mode_one(mode), NULL);

					if (tv != tarval_bad) {
						relation ^= ir_relation_equal;
						changedc = true;
						DBG_OPT_ALGSIM0(n, n, FS_OPT_CMP_CNST_MAGN);
					}
				}
				/* c < 0 : a > c  ==>  a >= (c+1)    a <= c  ==>  a < (c+1) */
				else if ((relation == ir_relation_greater || relation == ir_relation_less_equal) &&
					tarval_cmp(tv, get_mode_null(mode)) == ir_relation_less) {
					tv = tarval_add(tv, get_mode_one(mode));

					if (tv != tarval_bad) {
						relation ^= ir_relation_equal;
						changedc = true;
						DBG_OPT_ALGSIM0(n, n, FS_OPT_CMP_CNST_MAGN);
					}
				}

				/* the following reassociations work only for == and != */
				if (relation == ir_relation_equal || relation == ir_relation_less_greater) {
					if (tv != tarval_bad) {
						/* a-c1 == c2  ==>  a == c2+c1,  a-c1 != c2  ==>  a != c2+c1 */
						if (is_Sub(left)) {
							ir_node *c1 = get_Sub_right(left);
							ir_tarval *tv2 = value_of(c1);

							if (tv2 != tarval_bad) {
								tv2 = tarval_add(tv, value_of(c1));

								if (tv2 != tarval_bad) {
									left    = get_Sub_left(left);
									tv      = tv2;
									changedc = true;
									DBG_OPT_ALGSIM0(n, n, FS_OPT_CMP_OP_C);
								}
							}
						}
						/* a+c1 == c2  ==>  a == c2-c1,  a+c1 != c2  ==>  a != c2-c1 */
						else if (is_Add(left) || is_Or_Eor_Add(left)) {
							ir_node *a_l = get_binop_left(left);
							ir_node *a_r = get_binop_right(left);
							ir_node *a;
							ir_tarval *tv2;

							if (is_Const(a_l)) {
								a = a_r;
								tv2 = value_of(a_l);
							} else {
								a = a_l;
								tv2 = value_of(a_r);
							}

							if (tv2 != tarval_bad) {
								tv2 = tarval_sub(tv, tv2, NULL);

								if (tv2 != tarval_bad) {
									left    = a;
									tv      = tv2;
									changedc = true;
									DBG_OPT_ALGSIM0(n, n, FS_OPT_CMP_OP_C);
								}
							}
						}
						/* -a == c ==> a == -c, -a != c ==> a != -c */
						else if (is_Minus(left)) {
							ir_tarval *tv2 = tarval_sub(get_mode_null(mode), tv, NULL);

							if (tv2 != tarval_bad) {
								left    = get_Minus_op(left);
								tv      = tv2;
								changedc = true;
								DBG_OPT_ALGSIM0(n, n, FS_OPT_CMP_OP_C);
							}
						}
					}
				}
			}

			if (relation == ir_relation_equal || relation == ir_relation_less_greater) {
				switch (get_irn_opcode(left)) {
					ir_node *c1;

				case iro_And:
					c1 = get_And_right(left);
					if (is_Const(c1)) {
						/*
						 * And(x, C1) == C2 ==> FALSE if C2 & C1 != C2
						 * And(x, C1) != C2 ==> TRUE if C2 & C1 != C2
						 */
						ir_tarval *mask = tarval_and(get_Const_tarval(c1), tv);
						if (mask != tv) {
							/* TODO: move to constant evaluation */
							ir_graph *irg = get_irn_irg(n);
							tv = relation == ir_relation_equal ? get_tarval_b_false() : get_tarval_b_true();
							c1 = new_r_Const(irg, tv);
							DBG_OPT_CSTEVAL(n, c1);
							return c1;
						}

						if (tarval_is_single_bit(tv)) {
							/*
							 * optimization for AND:
							 * Optimize:
							 *   And(x, C) == C  ==>  And(x, C) != 0
							 *   And(x, C) != C  ==>  And(X, C) == 0
							 *
							 * if C is a single Bit constant.
							 */

							/* check for Constant's match. We have check hare the tarvals,
							   because our const might be changed */
							if (get_Const_tarval(c1) == tv) {
								/* fine: do the transformation */
								tv = get_mode_null(get_tarval_mode(tv));
								relation ^= ir_relation_less_equal_greater;
								changedc = true;
								DBG_OPT_ALGSIM0(n, n, FS_OPT_CMP_CNST_MAGN);
							}
						}
					}
					break;
				case iro_Or:
					c1 = get_Or_right(left);
					if (is_Const(c1) && tarval_is_null(tv)) {
						/*
						 * Or(x, C) == 0  && C != 0 ==> FALSE
						 * Or(x, C) != 0  && C != 0 ==> TRUE
						 */
						if (! tarval_is_null(get_Const_tarval(c1))) {
							/* TODO: move to constant evaluation */
							ir_graph *irg = get_irn_irg(n);
							tv = relation == ir_relation_equal ? get_tarval_b_false() : get_tarval_b_true();
							c1 = new_r_Const(irg, tv);
							DBG_OPT_CSTEVAL(n, c1);
							return c1;
						}
					}
					break;
				case iro_Shl:
					/*
					 * optimize x << c1 == c into x & (-1 >>u c1) == c >> c1  if  c & (-1 << c1) == c
					 *                             FALSE                       else
					 * optimize x << c1 != c into x & (-1 >>u c1) != c >> c1  if  c & (-1 << c1) == c
					 *                             TRUE                        else
					 */
					c1 = get_Shl_right(left);
					if (is_Const(c1)) {
						ir_graph  *irg    = get_irn_irg(c1);
						ir_tarval *tv1    = get_Const_tarval(c1);
						ir_mode   *mode   = get_irn_mode(left);
						ir_tarval *minus1 = get_mode_all_one(mode);
						ir_tarval *amask  = tarval_shr(minus1, tv1);
						ir_tarval *cmask  = tarval_shl(minus1, tv1);
						ir_node   *sl, *blk;

						if (tarval_and(tv, cmask) != tv) {
							/* condition not met */
							tv = relation == ir_relation_equal ? get_tarval_b_false() : get_tarval_b_true();
							c1 = new_r_Const(irg, tv);
							DBG_OPT_CSTEVAL(n, c1);
							return c1;
						}
						sl   = get_Shl_left(left);
						blk  = get_nodes_block(n);
						left = new_rd_And(get_irn_dbg_info(left), blk, sl, new_r_Const(irg, amask), mode);
						tv   = tarval_shr(tv, tv1);
						changedc = true;
						DBG_OPT_ALGSIM0(n, n, FS_OPT_CMP_SHF_TO_AND);
					}
					break;
				case iro_Shr:
					/*
					 * optimize x >>u c1 == c into x & (-1 << c1) == c << c1  if  c & (-1 >>u c1) == c
					 *                             FALSE                       else
					 * optimize x >>u c1 != c into x & (-1 << c1) != c << c1  if  c & (-1 >>u c1) == c
					 *                             TRUE                        else
					 */
					c1 = get_Shr_right(left);
					if (is_Const(c1)) {
						ir_graph  *irg    = get_irn_irg(c1);
						ir_tarval *tv1    = get_Const_tarval(c1);
						ir_mode   *mode   = get_irn_mode(left);
						ir_tarval *minus1 = get_mode_all_one(mode);
						ir_tarval *amask  = tarval_shl(minus1, tv1);
						ir_tarval *cmask  = tarval_shr(minus1, tv1);
						ir_node   *sl, *blk;

						if (tarval_and(tv, cmask) != tv) {
							/* condition not met */
							tv = relation == ir_relation_equal ? get_tarval_b_false() : get_tarval_b_true();
							c1 = new_r_Const(irg, tv);
							DBG_OPT_CSTEVAL(n, c1);
							return c1;
						}
						sl   = get_Shr_left(left);
						blk  = get_nodes_block(n);
						left = new_rd_And(get_irn_dbg_info(left), blk, sl, new_r_Const(irg, amask), mode);
						tv   = tarval_shl(tv, tv1);
						changedc = true;
						DBG_OPT_ALGSIM0(n, n, FS_OPT_CMP_SHF_TO_AND);
					}
					break;
				case iro_Shrs:
					/*
					 * optimize x >>s c1 == c into x & (-1 << c1) == c << c1  if  (c >>s (BITS - c1)) \in {0,-1}
					 *                             FALSE                       else
					 * optimize x >>s c1 != c into x & (-1 << c1) != c << c1  if  (c >>s (BITS - c1)) \in {0,-1}
					 *                             TRUE                        else
					 */
					c1 = get_Shrs_right(left);
					if (is_Const(c1)) {
						ir_graph  *irg    = get_irn_irg(c1);
						ir_tarval *tv1    = get_Const_tarval(c1);
						ir_mode   *mode   = get_irn_mode(left);
						ir_tarval *minus1 = get_mode_all_one(mode);
						ir_tarval *amask  = tarval_shl(minus1, tv1);
						ir_tarval *cond   = new_tarval_from_long(get_mode_size_bits(mode), get_tarval_mode(tv1));
						ir_node *sl, *blk;

						cond = tarval_sub(cond, tv1, NULL);
						cond = tarval_shrs(tv, cond);

						if (!tarval_is_all_one(cond) && !tarval_is_null(cond)) {
							/* condition not met */
							tv = relation == ir_relation_equal ? get_tarval_b_false() : get_tarval_b_true();
							c1 = new_r_Const(irg, tv);
							DBG_OPT_CSTEVAL(n, c1);
							return c1;
						}
						sl   = get_Shrs_left(left);
						blk  = get_nodes_block(n);
						left = new_rd_And(get_irn_dbg_info(left), blk, sl, new_r_Const(irg, amask), mode);
						tv   = tarval_shl(tv, tv1);
						changedc = true;
						DBG_OPT_ALGSIM0(n, n, FS_OPT_CMP_SHF_TO_AND);
					}
					break;
				}
			}
		}
	}

	if (changedc) {     /* need a new Const */
		ir_graph *irg = get_irn_irg(n);
		right = new_r_Const(irg, tv);
		changed = true;
	}

	if ((relation == ir_relation_equal || relation == ir_relation_less_greater) && is_Const(right) && is_Const_null(right) && is_Proj(left)) {
		ir_node *op = get_Proj_pred(left);

		if (is_Mod(op) && get_Proj_proj(left) == pn_Mod_res) {
			ir_node *c = get_binop_right(op);

			if (is_Const(c)) {
				ir_tarval *tv = get_Const_tarval(c);

				if (tarval_is_single_bit(tv)) {
					/* special case: (x % 2^n) CMP 0 ==> x & (2^n-1) CMP 0 */
					ir_node *v    = get_binop_left(op);
					ir_node *blk  = get_nodes_block(op);
					ir_graph *irg = get_irn_irg(op);
					ir_mode *mode = get_irn_mode(v);

					tv = tarval_sub(tv, get_mode_one(mode), NULL);
					left = new_rd_And(get_irn_dbg_info(op), blk, v, new_r_Const(irg, tv), mode);
					changed = true;
					DBG_OPT_ALGSIM0(n, n, FS_OPT_CMP_MOD_TO_AND);
				}
			}
		}
	}

	if (changed) {
		dbg_info *dbgi  = get_irn_dbg_info(n);
		ir_node  *block = get_nodes_block(n);

		/* create a new compare */
		n = new_rd_Cmp(dbgi, block, left, right, relation);
	}

	return n;
}

/**
 * Optimize CopyB(mem, x, x) into a Nop.
 */
static ir_node *transform_node_Proj_CopyB(ir_node *proj)
{
	ir_node *copyb = get_Proj_pred(proj);
	ir_node *a     = get_CopyB_dst(copyb);
	ir_node *b     = get_CopyB_src(copyb);

	if (a == b) {
		switch (get_Proj_proj(proj)) {
		case pn_CopyB_X_regular:
			/* Turn CopyB into a tuple (mem, jmp, bad, bad) */
			DBG_OPT_EXC_REM(proj);
			proj = new_r_Jmp(get_nodes_block(copyb));
			break;
		case pn_CopyB_X_except: {
			ir_graph *irg = get_irn_irg(proj);
			DBG_OPT_EXC_REM(proj);
			proj = new_r_Bad(irg, mode_X);
			break;
		}
		default:
			break;
		}
	}
	return proj;
}

/**
 * Optimize Bounds(idx, idx, upper) into idx.
 */
static ir_node *transform_node_Proj_Bound(ir_node *proj)
{
	ir_node *oldn  = proj;
	ir_node *bound = get_Proj_pred(proj);
	ir_node *idx   = get_Bound_index(bound);
	ir_node *pred  = skip_Proj(idx);
	int ret_tuple  = 0;

	if (idx == get_Bound_lower(bound))
		ret_tuple = 1;
	else if (is_Bound(pred)) {
		/*
		* idx was Bounds checked previously, it is still valid if
		* lower <= pred_lower && pred_upper <= upper.
		*/
		ir_node *lower = get_Bound_lower(bound);
		ir_node *upper = get_Bound_upper(bound);
		if (get_Bound_lower(pred) == lower &&
			get_Bound_upper(pred) == upper) {
			/*
			 * One could expect that we simply return the previous
			 * Bound here. However, this would be wrong, as we could
			 * add an exception Proj to a new location then.
			 * So, we must turn in into a tuple.
			 */
			ret_tuple = 1;
		}
	}
	if (ret_tuple) {
		/* Turn Bound into a tuple (mem, jmp, bad, idx) */
		switch (get_Proj_proj(proj)) {
		case pn_Bound_M:
			DBG_OPT_EXC_REM(proj);
			proj = get_Bound_mem(bound);
			break;
		case pn_Bound_X_except:
			DBG_OPT_EXC_REM(proj);
			proj = new_r_Bad(get_irn_irg(proj), mode_X);
			break;
		case pn_Bound_res:
			proj = idx;
			DBG_OPT_ALGSIM0(oldn, proj, FS_OPT_NOP);
			break;
		case pn_Bound_X_regular:
			DBG_OPT_EXC_REM(proj);
			proj = new_r_Jmp(get_nodes_block(bound));
			break;
		default:
			break;
		}
	}
	return proj;
}

/**
 * Does all optimizations on nodes that must be done on its Projs
 * because of creating new nodes.
 */
static ir_node *transform_node_Proj(ir_node *proj)
{
	ir_node *n = get_Proj_pred(proj);

	if (n->op->ops.transform_node_Proj)
		return n->op->ops.transform_node_Proj(proj);
	return proj;
}

/**
 * Test whether a block is unreachable
 * Note: That this only returns true when
 * IR_GRAPH_CONSTRAINT_OPTIMIZE_UNREACHABLE_CODE is set.
 * This is important, as you easily end up producing invalid constructs in the
 * unreachable code when optimizing away edges into the unreachable code.
 * So only set this flag when you iterate localopts to the fixpoint.
 * When you reach the fixpoint then all unreachable code is dead
 * (= can't be reached by firm edges) and you won't see the invalid constructs
 * anymore.
 */
static bool is_block_unreachable(const ir_node *block)
{
	const ir_graph *irg = get_irn_irg(block);
	if (!irg_is_constrained(irg, IR_GRAPH_CONSTRAINT_OPTIMIZE_UNREACHABLE_CODE))
		return false;
	return get_Block_dom_depth(block) < 0;
}

static ir_node *transform_node_Block(ir_node *block)
{
	ir_graph *irg   = get_irn_irg(block);
	int       arity = get_irn_arity(block);
	ir_node  *bad   = NULL;
	int       i;

	if (!irg_is_constrained(irg, IR_GRAPH_CONSTRAINT_OPTIMIZE_UNREACHABLE_CODE))
		return block;

	for (i = 0; i < arity; ++i) {
		ir_node *const pred = get_Block_cfgpred(block, i);
		if (is_Bad(pred) || !is_block_unreachable(get_nodes_block(pred)))
			continue;
		if (bad == NULL)
			bad = new_r_Bad(irg, mode_X);
		set_irn_n(block, i, bad);
	}

	return block;
}

static ir_node *transform_node_Phi(ir_node *phi)
{
	int       n     = get_irn_arity(phi);
	ir_mode  *mode  = get_irn_mode(phi);
	ir_node  *block = get_nodes_block(phi);
	ir_graph *irg   = get_irn_irg(phi);
	ir_node  *bad   = NULL;
	int       i;

	/* Set phi-operands for bad-block inputs to bad */
	for (i = 0; i < n; ++i) {
		if (!is_Bad(get_Phi_pred(phi, i))) {
			ir_node *pred = get_Block_cfgpred(block, i);
			if (is_Bad(pred) || is_block_unreachable(get_nodes_block(pred))) {
				if (bad == NULL)
					bad = new_r_Bad(irg, mode);
				set_irn_n(phi, i, bad);
			}
		}
	}

	/* Move Pin nodes down through Phi nodes. */
	if (mode == mode_M) {
		n = get_irn_arity(phi);

		/* Beware of Phi0 */
		if (n > 0) {
			ir_node **in;
			ir_node  *new_phi;
			bool      has_pin = false;

			NEW_ARR_A(ir_node *, in, n);

			for (i = 0; i < n; ++i) {
				ir_node *pred = get_irn_n(phi, i);

				if (is_Pin(pred)) {
					in[i]   = get_Pin_op(pred);
					has_pin = true;
				} else if (is_Bad(pred)) {
					in[i] = pred;
				} else {
					return phi;
				}
			}

			if (!has_pin)
				return phi;

			/* Move the Pin nodes "behind" the Phi. */
			new_phi = new_r_Phi(block, n, in, mode_M);
			return new_r_Pin(block, new_phi);
		}
	}
	/* Move Confirms down through Phi nodes. */
	else if (mode_is_reference(mode)) {
		n = get_irn_arity(phi);

		/* Beware of Phi0 */
		if (n > 0) {
			ir_node    *pred = get_irn_n(phi, 0);
			ir_node    *bound, *new_phi, **in;
			ir_relation relation;
			bool        has_confirm = false;

			if (! is_Confirm(pred))
				return phi;

			bound    = get_Confirm_bound(pred);
			relation = get_Confirm_relation(pred);

			NEW_ARR_A(ir_node *, in, n);
			in[0] = get_Confirm_value(pred);

			for (i = 1; i < n; ++i) {
				pred = get_irn_n(phi, i);

				if (is_Confirm(pred) &&
						get_Confirm_bound(pred) == bound &&
						get_Confirm_relation(pred) == relation) {
					in[i]       = get_Confirm_value(pred);
					has_confirm = true;
				} else if (is_Bad(pred)) {
					in[i] = pred;
				} else {
					return phi;
				}
			}

			if (!has_confirm)
				return phi;

			/* move the Confirm nodes "behind" the Phi */
			new_phi = new_r_Phi(block, n, in, get_irn_mode(phi));
			return new_r_Confirm(block, new_phi, bound, relation);
		}
	}
	return phi;
}

/**
 * Optimize (a >> c1) >> c2), works for Shr, Shrs, Shl, Rotl.
 *
 * Should be moved to reassociation?
 */
static ir_node *transform_node_shift(ir_node *n)
{
	ir_node *left, *right;
	ir_mode *mode;
	ir_mode *count_mode;
	ir_tarval *tv1, *tv2, *res;
	ir_node *in[2], *irn, *block;
	ir_graph *irg;
	int       modulo_shf;

	left = get_binop_left(n);

	/* different operations */
	if (get_irn_op(left) != get_irn_op(n))
		return n;

	right = get_binop_right(n);
	tv1   = value_of(right);
	if (tv1 == tarval_bad)
		return n;

	tv2 = value_of(get_binop_right(left));
	if (tv2 == tarval_bad)
		return n;

	count_mode = get_tarval_mode(tv1);
	if (get_tarval_mode(tv2) != count_mode) {
		/* TODO: search bigger mode or something and convert... */
		return n;
	}

	mode       = get_irn_mode(n);
	modulo_shf = get_mode_modulo_shift(mode);

	if (modulo_shf > 0) {
		ir_tarval *modulo_mask = new_tarval_from_long(modulo_shf-1, count_mode);

		/* I'm not so sure what happens in one complement... */
		assert(get_mode_arithmetic(count_mode) == irma_twos_complement);
		/* modulo shifts should always be a power of 2 (otherwise modulo_mask
		 * above will be invalid) */
		assert(modulo_shf<=0 || is_po2(modulo_shf));

		tv1 = tarval_and(tv1, modulo_mask);
		tv2 = tarval_and(tv2, modulo_mask);
	}
	res = tarval_add(tv1, tv2);
	irg = get_irn_irg(n);

	/* beware: a simple replacement works only, if res < modulo shift */
	if (is_Rotl(n)) {
		int        bits   = get_mode_size_bits(mode);
		ir_tarval *modulo = new_tarval_from_long(bits, count_mode);
		res = tarval_mod(res, modulo);
	} else {
		long       bits      = get_mode_size_bits(mode);
		ir_tarval *mode_size = new_tarval_from_long(bits, count_mode);

		/* shifting too much */
		if (!(tarval_cmp(res, mode_size) & ir_relation_less)) {
			if (is_Shrs(n)) {
				ir_node  *block = get_nodes_block(n);
				dbg_info *dbgi  = get_irn_dbg_info(n);
				ir_mode  *smode = get_irn_mode(right);
				ir_node  *cnst  = new_r_Const_long(irg, smode, get_mode_size_bits(mode) - 1);
				return new_rd_Shrs(dbgi, block, get_binop_left(left), cnst, mode);
			}

			return new_r_Const(irg, get_mode_null(mode));
		}
	}

	/* ok, we can replace it */
	assert(modulo_shf >= (int) get_mode_size_bits(mode));
	block = get_nodes_block(n);

	in[0] = get_binop_left(left);
	in[1] = new_r_Const(irg, res);

	irn = new_ir_node(NULL, get_Block_irg(block), block, get_irn_op(n), mode, 2, in);

	DBG_OPT_ALGSIM0(n, irn, FS_OPT_REASSOC_SHIFT);

	return irn;
}

/**
 * normalisation:
 *    (x << c1) >> c2  <=>  x OP (c2-c1) & ((-1 << c1) >> c2)
 *    also:
 *    (x >> c1) << c2  <=>  x OP (c2-c1) & ((-1 >> c1) << c2)
 *      (also with x >>s c1  when c1>=c2)
 */
static ir_node *transform_node_shl_shr(ir_node *n)
{
	ir_node   *left;
	ir_node   *right = get_binop_right(n);
	ir_node   *x;
	ir_node   *block;
	ir_mode   *mode;
	dbg_info  *dbgi;
	ir_node   *new_const;
	ir_node   *new_shift;
	ir_node   *new_and;
	ir_tarval *tv_shl;
	ir_tarval *tv_shr;
	ir_tarval *tv_shift;
	ir_tarval *tv_mask;
	ir_graph  *irg;
	ir_relation relation;
	int        need_shrs = 0;

	assert(is_Shl(n) || is_Shr(n) || is_Shrs(n));

	if (!is_Const(right))
		return n;

	left = get_binop_left(n);
	mode = get_irn_mode(n);
	if (is_Shl(n) && (is_Shr(left) || is_Shrs(left))) {
		ir_node *shr_right = get_binop_right(left);

		if (!is_Const(shr_right))
			return n;

		x      = get_binop_left(left);
		tv_shr = get_Const_tarval(shr_right);
		tv_shl = get_Const_tarval(right);

		if (is_Shrs(left)) {
			/* shrs variant only allowed if c1 >= c2 */
			if (! (tarval_cmp(tv_shl, tv_shr) & ir_relation_greater_equal))
				return n;

			tv_mask = tarval_shrs(get_mode_all_one(mode), tv_shr);
			need_shrs = 1;
		} else {
			tv_mask = tarval_shr(get_mode_all_one(mode), tv_shr);
		}
		tv_mask = tarval_shl(tv_mask, tv_shl);
	} else if (is_Shr(n) && is_Shl(left)) {
		ir_node *shl_right = get_Shl_right(left);

		if (!is_Const(shl_right))
			return n;

		x      = get_Shl_left(left);
		tv_shr = get_Const_tarval(right);
		tv_shl = get_Const_tarval(shl_right);

		tv_mask = tarval_shl(get_mode_all_one(mode), tv_shl);
		tv_mask = tarval_shr(tv_mask, tv_shr);
	} else {
		return n;
	}

	if (get_tarval_mode(tv_shl) != get_tarval_mode(tv_shr)) {
		tv_shl = tarval_convert_to(tv_shl, get_tarval_mode(tv_shr));
	}

	assert(tv_mask != tarval_bad);
	assert(get_tarval_mode(tv_mask) == mode);

	block = get_nodes_block(n);
	irg   = get_irn_irg(block);
	dbgi  = get_irn_dbg_info(n);

	relation = tarval_cmp(tv_shl, tv_shr);
	if (relation == ir_relation_less || relation == ir_relation_equal) {
		tv_shift  = tarval_sub(tv_shr, tv_shl, NULL);
		new_const = new_r_Const(irg, tv_shift);
		if (need_shrs) {
			new_shift = new_rd_Shrs(dbgi, block, x, new_const, mode);
		} else {
			new_shift = new_rd_Shr(dbgi, block, x, new_const, mode);
		}
	} else {
		assert(relation == ir_relation_greater);
		tv_shift  = tarval_sub(tv_shl, tv_shr, NULL);
		new_const = new_r_Const(irg, tv_shift);
		new_shift = new_rd_Shl(dbgi, block, x, new_const, mode);
	}

	new_const = new_r_Const(irg, tv_mask);
	new_and   = new_rd_And(dbgi, block, new_shift, new_const, mode);

	return new_and;
}

static ir_tarval *get_modulo_tv_value(ir_tarval *tv, int modulo_val)
{
	ir_mode   *mode      = get_tarval_mode(tv);
	ir_tarval *modulo_tv = new_tarval_from_long(modulo_val, mode);
	return tarval_mod(tv, modulo_tv);
}

typedef ir_node*(*new_shift_func)(dbg_info *dbgi, ir_node *block,
                                  ir_node *left, ir_node *right, ir_mode *mode);

/**
 * Normalisation: if we have a shl/shr with modulo_shift behaviour
 * then we can use that to minimize the value of Add(x, const) or
 * Sub(Const, x). In particular this often avoids 1 instruction in some
 * backends for the Shift(x, Sub(Const, y)) case because it can be replaced
 * by Shift(x, Minus(y)) which does not need an explicit Const constructed.
 */
static ir_node *transform_node_shift_modulo(ir_node *n,
                                            new_shift_func new_shift)
{
	ir_mode  *mode   = get_irn_mode(n);
	int       modulo = get_mode_modulo_shift(mode);
	ir_node  *newop  = NULL;
	ir_mode  *mode_right;
	ir_node  *block;
	ir_node  *right;
	ir_graph *irg;

	if (modulo == 0)
		return n;
	if (get_mode_arithmetic(mode) != irma_twos_complement)
		return n;
	if (!is_po2(modulo))
		return n;

	irg        = get_irn_irg(n);
	block      = get_nodes_block(n);
	right      = get_binop_right(n);
	mode_right = get_irn_mode(right);
	if (is_Const(right)) {
		ir_tarval *tv     = get_Const_tarval(right);
		ir_tarval *tv_mod = get_modulo_tv_value(tv, modulo);

		if (tv_mod == tv)
			return n;

		newop = new_r_Const(irg, tv_mod);
	} else if (is_Add(right) || is_Or_Eor_Add(right)) {
		ir_node *add_right = get_binop_right(right);
		if (is_Const(add_right)) {
			ir_tarval *tv     = get_Const_tarval(add_right);
			ir_tarval *tv_mod = get_modulo_tv_value(tv, modulo);
			ir_node   *newconst;
			if (tv_mod == tv)
				return n;

			newconst = new_r_Const(irg, tv_mod);
			newop    = new_r_Add(block, get_binop_left(right), newconst,
			                     mode_right);
		}
	} else if (is_Sub(right)) {
		ir_node *sub_left = get_Sub_left(right);
		if (is_Const(sub_left)) {
			ir_tarval *tv     = get_Const_tarval(sub_left);
			ir_tarval *tv_mod = get_modulo_tv_value(tv, modulo);
			ir_node  *newconst;
			if (tv_mod == tv)
				return n;

			newconst = new_r_Const(irg, tv_mod);
			newop    = new_r_Sub(block, newconst, get_Sub_right(right),
			                     mode_right);
		}
	} else {
		return n;
	}

	if (newop != NULL) {
		dbg_info *dbgi = get_irn_dbg_info(n);
		ir_node  *left = get_binop_left(n);
		return new_shift(dbgi, block, left, newop, mode);
	}
	return n;
}

/**
 * Transform a Shr.
 */
static ir_node *transform_node_Shr(ir_node *n)
{
	ir_node *c, *oldn = n;
	ir_node *left  = get_Shr_left(n);
	ir_node *right = get_Shr_right(n);
	ir_mode *mode  = get_irn_mode(n);

	HANDLE_BINOP_PHI((eval_func) tarval_shr, left, right, c, mode);
	n = transform_node_shift(n);

	if (is_Shr(n))
		n = transform_node_shift_modulo(n, new_rd_Shr);
	if (is_Shr(n))
		n = transform_node_shl_shr(n);
	if (is_Shr(n))
		n = transform_node_shift_bitop(n);

	return n;
}

/**
 * Transform a Shrs.
 */
static ir_node *transform_node_Shrs(ir_node *n)
{
	ir_node  *oldn = n;
	ir_node  *a    = get_Shrs_left(n);
	ir_node  *b    = get_Shrs_right(n);
	ir_mode  *mode = get_irn_mode(n);
	ir_node  *c;
	vrp_attr *attr;

	if (is_oversize_shift(n)) {
		ir_node  *block = get_nodes_block(n);
		dbg_info *dbgi  = get_irn_dbg_info(n);
		ir_mode  *cmode = get_irn_mode(b);
		long      val   = get_mode_size_bits(cmode)-1;
		ir_graph *irg   = get_irn_irg(n);
		ir_node  *cnst  = new_r_Const_long(irg, cmode, val);
		return new_rd_Shrs(dbgi, block, a, cnst, mode);
	}

	HANDLE_BINOP_PHI((eval_func) tarval_shrs, a, b, c, mode);
	n = transform_node_shift(n);
	if (n != oldn)
		return n;

	n = transform_node_shift_modulo(n, new_rd_Shrs);
	if (n != oldn)
		return n;
	n = transform_node_shift_bitop(n);
	if (n != oldn)
		return n;

	/* normalisation: use Shr when sign bit is guaranteed to be cleared */
	attr = vrp_get_info(a);
	if (attr != NULL) {
		unsigned   bits   = get_mode_size_bits(mode);
		ir_tarval *scount = new_tarval_from_long(bits-1, mode_Iu);
		ir_tarval *sign   = tarval_shl(get_mode_one(mode), scount);
		if (tarval_is_null(tarval_and(attr->bits_not_set, sign))) {
			dbg_info *dbgi  = get_irn_dbg_info(n);
			ir_node  *block = get_nodes_block(n);
			return new_rd_Shr(dbgi, block, a, b, mode);
		}
	}

	return n;
}

/**
 * Transform a Shl.
 */
static ir_node *transform_node_Shl(ir_node *n)
{
	ir_node *c, *oldn = n;
	ir_node *a    = get_Shl_left(n);
	ir_node *b    = get_Shl_right(n);
	ir_mode *mode = get_irn_mode(n);

	HANDLE_BINOP_PHI((eval_func) tarval_shl, a, b, c, mode);
	n = transform_node_shift(n);

	if (is_Shl(n))
		n = transform_node_shift_modulo(n, new_rd_Shl);
	if (is_Shl(n))
		n = transform_node_shl_shr(n);
	if (is_Shl(n))
		n = transform_node_shift_bitop(n);

	return n;
}

/**
 * Transform a Rotl.
 */
static ir_node *transform_node_Rotl(ir_node *n)
{
	ir_node *c, *oldn = n;
	ir_node *a    = get_Rotl_left(n);
	ir_node *b    = get_Rotl_right(n);
	ir_mode *mode = get_irn_mode(n);

	HANDLE_BINOP_PHI((eval_func) tarval_rotl, a, b, c, mode);
	n = transform_node_shift(n);

	if (is_Rotl(n))
		n = transform_node_shift_bitop(n);

	return n;
}

/**
 * returns mode size for may_leave_out_middle_mode
 */
static unsigned get_significand_size(ir_mode *mode)
{
	const ir_mode_arithmetic arithmetic = get_mode_arithmetic(mode);
	switch (arithmetic) {
	case irma_ieee754:
	case irma_x86_extended_float:
		return get_mode_mantissa_size(mode) + 1;
	case irma_twos_complement:
		return get_mode_size_bits(mode);
	case irma_none:
		panic("Conv node with irma_none mode?");
	}
	panic("unexpected mode_arithmetic in get_significand_size");
}

/**
 * Returns true if a conversion from mode @p m0 to @p m1 has the same effect
 * as converting from @p m0 to @p m1 and then to @p m2.
 * Classifying the 3 modes as the big(b), middle(m) and small(s) mode this
 * gives the following truth table:
 * s -> b -> m  : true
 * s -> m -> b  : !signed(s) || signed(m)
 * m -> b -> s  : true
 * m -> s -> b  : false
 * b -> s -> m  : false
 * b -> m -> s  : true
 *
 * s -> b -> b  : true
 * s -> s -> b  : false
 *
 * additional float constraints:
 * F -> F -> F: fine
 * F -> I -> I: signedness of Is must match
 * I -> F -> I: signedness of Is must match
 * I -> I -> F: signedness of Is must match
 * F -> I -> F: bad
 * I -> F -> F: fine
 * F -> F -> I: fine
 * at least 1 float involved: signedness must match
 */
bool may_leave_out_middle_conv(ir_mode *m0, ir_mode *m1, ir_mode *m2)
{
	int n_floats = mode_is_float(m0) + mode_is_float(m1) + mode_is_float(m2);
	if (n_floats == 1) {
#if 0
		int n_signed = mode_is_signed(m0) + mode_is_signed(m1)
		             + mode_is_signed(m2);
		/* we assume that float modes are always signed */
		if ((n_signed & 1) != 1)
			return false;
#else
		/* because overflow gives strange results we don't touch this case */
		return false;
#endif
	} else if (n_floats == 2 && !mode_is_float(m1)) {
		return false;
	}

	unsigned size0 = get_significand_size(m0);
	unsigned size1 = get_significand_size(m1);
	unsigned size2 = get_significand_size(m2);
	if (size1 < size2 && size0 >= size1)
		return false;
	if (size1 >= size2)
		return true;
	return !mode_is_signed(m0) || mode_is_signed(m1);
}

/**
 * Transform a Conv.
 */
static ir_node *transform_node_Conv(ir_node *n)
{
	ir_node *c, *oldn = n;
	ir_mode *mode = get_irn_mode(n);
	ir_node *a    = get_Conv_op(n);

	if (is_Conv(a)) {
		ir_mode *a_mode = get_irn_mode(a);
		ir_node *b      = get_Conv_op(a);
		ir_mode *b_mode = get_irn_mode(b);
		if (may_leave_out_middle_conv(b_mode, a_mode, mode)) {
			dbg_info *dbgi  = get_irn_dbg_info(n);
			ir_node  *block = get_nodes_block(n);
			return new_rd_Conv(dbgi, block, b, mode);
		}
	}

	if (mode != mode_b && is_const_Phi(a)) {
		/* Do NOT optimize mode_b Conv's, this leads to remaining
		 * Phib nodes later, because the conv_b_lower operation
		 * is instantly reverted, when it tries to insert a Convb.
		 */
		c = apply_conv_on_phi(a, mode);
		if (c) {
			DBG_OPT_ALGSIM0(oldn, c, FS_OPT_CONST_PHI);
			return c;
		}
	}

	if (is_Unknown(a)) { /* Conv_A(Unknown_B) -> Unknown_A */
		ir_graph *irg = get_irn_irg(n);
		return new_r_Unknown(irg, mode);
	}

	if (mode_is_reference(mode) &&
	        get_mode_size_bits(mode) == get_mode_size_bits(get_irn_mode(a)) &&
	        is_Add(a)) {
		ir_node *l = get_Add_left(a);
		ir_node *r = get_Add_right(a);
		dbg_info *dbgi = get_irn_dbg_info(a);
		ir_node *block = get_nodes_block(n);
		if (is_Conv(l)) {
			ir_node *lop = get_Conv_op(l);
			if (get_irn_mode(lop) == mode) {
				/* ConvP(AddI(ConvI(P), x)) -> AddP(P, x) */
				n = new_rd_Add(dbgi, block, lop, r, mode);
				return n;
			}
		}
		if (is_Conv(r)) {
			ir_node *rop = get_Conv_op(r);
			if (get_irn_mode(rop) == mode) {
				/* ConvP(AddI(x, ConvI(P))) -> AddP(x, P) */
				n = new_rd_Add(dbgi, block, l, rop, mode);
				return n;
			}
		}
	}

	return n;
}

/**
 * Remove dead blocks and nodes in dead blocks
 * in keep alive list.  We do not generate a new End node.
 */
static ir_node *transform_node_End(ir_node *n)
{
	int i, j, n_keepalives = get_End_n_keepalives(n);
	ir_node **in;

	NEW_ARR_A(ir_node *, in, n_keepalives);

	for (i = j = 0; i < n_keepalives; ++i) {
		ir_node *ka = get_End_keepalive(n, i);
		ir_node *block;
		/* no need to keep Bad */
		if (is_Bad(ka))
			continue;
		/* do not keep unreachable code */
		block = is_Block(ka) ? ka : get_nodes_block(ka);
		if (is_block_unreachable(block))
			continue;
		in[j++] = ka;
	}
	if (j != n_keepalives)
		set_End_keepalives(n, j, in);
	return n;
}

int ir_is_negated_value(const ir_node *a, const ir_node *b)
{
	if (is_Minus(a) && get_Minus_op(a) == b)
		return true;
	if (is_Minus(b) && get_Minus_op(b) == a)
		return true;
	if (is_Sub(a) && is_Sub(b)) {
		ir_node *a_left  = get_Sub_left(a);
		ir_node *a_right = get_Sub_right(a);
		ir_node *b_left  = get_Sub_left(b);
		ir_node *b_right = get_Sub_right(b);

		if (a_left == b_right && a_right == b_left)
			return true;
	}

	return false;
}

static const ir_node *skip_upconv(const ir_node *node)
{
	while (is_Conv(node)) {
		ir_mode       *mode    = get_irn_mode(node);
		const ir_node *op      = get_Conv_op(node);
		ir_mode       *op_mode = get_irn_mode(op);
		if (!smaller_mode(op_mode, mode))
			break;
		node = op;
	}
	return node;
}

int ir_mux_is_abs(const ir_node *sel, const ir_node *mux_false,
                  const ir_node *mux_true)
{
	ir_node    *cmp_left;
	ir_node    *cmp_right;
	ir_mode    *mode;
	ir_relation relation;

	if (!is_Cmp(sel))
		return 0;

	/**
	 * Note further that these optimization work even for floating point
	 * with NaN's because -NaN == NaN.
	 * However, if +0 and -0 is handled differently, we cannot use the Abs/-Abs
	 * transformations.
	 */
	mode = get_irn_mode(mux_true);
	if (mode_honor_signed_zeros(mode))
		return 0;

	/* must be <, <=, >=, > */
	relation = get_Cmp_relation(sel);
	if ((relation & ir_relation_less_greater) == 0)
		return 0;

	if (!ir_is_negated_value(mux_true, mux_false))
		return 0;

	mux_true  = skip_upconv(mux_true);
	mux_false = skip_upconv(mux_false);

	/* must be x cmp 0 */
	cmp_right = get_Cmp_right(sel);
	if (!is_Const(cmp_right) || !is_Const_null(cmp_right))
		return 0;

	cmp_left = get_Cmp_left(sel);
	if (cmp_left == mux_false) {
		if (relation & ir_relation_less) {
			return 1;
		} else {
			assert(relation & ir_relation_greater);
			return -1;
		}
	} else if (cmp_left == mux_true) {
		if (relation & ir_relation_less) {
			return -1;
		} else {
			assert(relation & ir_relation_greater);
			return 1;
		}
	}

	return 0;
}

ir_node *ir_get_abs_op(const ir_node *sel, ir_node *mux_false,
                       ir_node *mux_true)
{
	ir_node *cmp_left = get_Cmp_left(sel);
	return cmp_left == skip_upconv(mux_false) ? mux_false : mux_true;
}

bool ir_is_optimizable_mux(const ir_node *sel, const ir_node *mux_false,
                           const ir_node *mux_true)
{
	/* this code should return true each time transform_node_Mux would
	 * optimize the Mux completely away */

	ir_mode *mode = get_irn_mode(mux_false);
	if (get_mode_arithmetic(mode) == irma_twos_complement
	    && ir_mux_is_abs(sel, mux_false, mux_true))
	    return true;

	if (is_Cmp(sel) && mode_is_int(mode) && is_cmp_equality_zero(sel)) {
		const ir_node *cmp_r = get_Cmp_right(sel);
		const ir_node *cmp_l = get_Cmp_left(sel);
		const ir_node *f     = mux_false;
		const ir_node *t     = mux_true;

		if (is_Const(t) && is_Const_null(t)) {
			t = mux_false;
			f = mux_true;
		}

		if (is_And(cmp_l) && f == cmp_r) {
			ir_node *and_r = get_And_right(cmp_l);
			ir_node *and_l;

			if (and_r == t && is_single_bit(and_r))
				return true;
			and_l = get_And_left(cmp_l);
			if (and_l == t && is_single_bit(and_l))
				return true;
		}
	}

	return false;
}

/**
 * Optimize a Mux(c, 0, 1) node (sometimes called a "set" instruction)
 */
static ir_node *transform_Mux_set(ir_node *n)
{
	ir_node    *cond = get_Mux_sel(n);
	ir_mode    *dest_mode;
	ir_mode    *mode;
	ir_node    *left;
	ir_node    *right;
	ir_relation relation;
	bool        need_not;
	dbg_info   *dbgi;
	ir_node    *block;
	ir_graph   *irg;
	ir_node    *a;
	ir_node    *b;
	unsigned    bits;
	ir_tarval  *tv;
	ir_node    *shift_cnt;
	ir_node    *res;

	if (!is_Cmp(cond))
		return n;
	left = get_Cmp_left(cond);
	mode = get_irn_mode(left);
	if (!mode_is_int(mode) && !mode_is_reference(mode))
		return n;
	dest_mode = get_irn_mode(n);
	if (!mode_is_int(dest_mode) && !mode_is_reference(dest_mode))
		return n;
	right     = get_Cmp_right(cond);
	relation  = get_Cmp_relation(cond) & ~ir_relation_unordered;
	if (get_mode_size_bits(mode) >= get_mode_size_bits(dest_mode)
	    && !(mode_is_signed(mode) && is_Const(right) && is_Const_null(right)
	         && relation != ir_relation_greater))
	    return n;

	need_not = false;
	switch (relation) {
	case ir_relation_less:
		/* a < b  ->  (a - b) >> 31 */
		a = left;
		b = right;
		break;
	case ir_relation_less_equal:
		/* a <= b  -> ~(a - b) >> 31 */
		a        = right;
		b        = left;
		need_not = true;
		break;
	case ir_relation_greater:
		/* a > b   -> (b - a) >> 31 */
		a = right;
		b = left;
		break;
	case ir_relation_greater_equal:
		/* a >= b   -> ~(a - b) >> 31 */
		a        = left;
		b        = right;
		need_not = true;
		break;
	default:
		return n;
	}

	dbgi      = get_irn_dbg_info(n);
	block     = get_nodes_block(n);
	irg       = get_irn_irg(block);
	bits      = get_mode_size_bits(dest_mode);
	tv        = new_tarval_from_long(bits-1, mode_Iu);
	shift_cnt = new_rd_Const(dbgi, irg, tv);

	if (mode != dest_mode) {
		a = new_rd_Conv(dbgi, block, a, dest_mode);
		b = new_rd_Conv(dbgi, block, b, dest_mode);
	}

	res = new_rd_Sub(dbgi, block, a, b, dest_mode);
	if (need_not) {
		res = new_rd_Not(dbgi, block, res, dest_mode);
	}
	res = new_rd_Shr(dbgi, block, res, shift_cnt, dest_mode);
	return res;
}

/**
 * Optimize a Mux into some simpler cases.
 */
static ir_node *transform_node_Mux(ir_node *n)
{
	ir_node  *oldn = n;
	ir_node  *sel  = get_Mux_sel(n);
	ir_mode  *mode = get_irn_mode(n);
	ir_node  *t    = get_Mux_true(n);
	ir_node  *f    = get_Mux_false(n);
	ir_graph *irg  = get_irn_irg(n);

	/* implement integer abs: abs(x) = x^(x >>s 31) - (x >>s 31) */
	if (get_mode_arithmetic(mode) == irma_twos_complement) {
		int abs = ir_mux_is_abs(sel, f, t);
		if (abs != 0) {
			dbg_info *dbgi       = get_irn_dbg_info(n);
			ir_node  *block      = get_nodes_block(n);
			ir_node  *op         = ir_get_abs_op(sel, f, t);
			int       bits       = get_mode_size_bits(mode);
			ir_node  *shiftconst = new_r_Const_long(irg, mode_Iu, bits-1);
			ir_node  *sext       = new_rd_Shrs(dbgi, block, op, shiftconst, mode);
			ir_node  *xorn       = new_rd_Eor(dbgi, block, op, sext, mode);
			ir_node  *res;
			if (abs > 0) {
				res = new_rd_Sub(dbgi, block, xorn, sext, mode);
			} else {
				res = new_rd_Sub(dbgi, block, sext, xorn, mode);
			}
			return res;
		}
	}

	/* first normalization step: try to move a constant to the false side,
	 * 0 preferred on false side too */
	if (is_Cmp(sel) && is_Const(t) &&
			(!is_Const(f) || (is_Const_null(t) && !is_Const_null(f)))) {
		dbg_info *seldbgi = get_irn_dbg_info(sel);
		ir_node  *block   = get_nodes_block(sel);
		ir_relation relation = get_Cmp_relation(sel);
		ir_node *tmp = t;
		t = f;
		f = tmp;

		/* Mux(x, a, b) => Mux(not(x), b, a) */
		relation = get_negated_relation(relation);
		sel = new_rd_Cmp(seldbgi, block, get_Cmp_left(sel),
				get_Cmp_right(sel), relation);
		return new_rd_Mux(get_irn_dbg_info(n), get_nodes_block(n), sel, f, t, mode);
	}

	if (is_Const(f) && is_Const_null(f) && is_Const(t) && is_Const_one(t)) {
		n = transform_Mux_set(n);
		if (n != oldn)
			return n;
	}

	/* the following optimisations create new mode_b nodes, so only do them
	 * before mode_b lowering */
	if (!irg_is_constrained(irg, IR_GRAPH_CONSTRAINT_MODEB_LOWERED)) {
		if (is_Mux(t)) {
			ir_node*  block = get_nodes_block(n);
			ir_node*  c0    = sel;
			ir_node*  c1    = get_Mux_sel(t);
			ir_node*  t1    = get_Mux_true(t);
			ir_node*  f1    = get_Mux_false(t);
			if (f == f1) {
				/* Mux(cond0, Mux(cond1, x, y), y) => Mux(cond0 && cond1, x, y) */
				ir_node* and_ = new_r_And(block, c0, c1, mode_b);
				DBG_OPT_ALGSIM0(oldn, t1, FS_OPT_MUX_COMBINE);
				return new_r_Mux(block, and_, f1, t1, mode);
			} else if (f == t1) {
				/* Mux(cond0, Mux(cond1, x, y), x) */
				ir_node* not_c1  = new_r_Not(block, c1, mode_b);
				ir_node* and_    = new_r_And(block, c0, not_c1, mode_b);
				DBG_OPT_ALGSIM0(oldn, f1, FS_OPT_MUX_COMBINE);
				return new_r_Mux(block, and_, t1, f1, mode);
			}
		} else if (is_Mux(f)) {
			ir_node*  block = get_nodes_block(n);
			ir_node*  c0    = sel;
			ir_node*  c1    = get_Mux_sel(f);
			ir_node*  t1    = get_Mux_true(f);
			ir_node*  f1    = get_Mux_false(f);
			if (t == t1) {
				/* Mux(cond0, x, Mux(cond1, x, y)) -> typical if (cond0 || cond1) x else y */
				ir_node* or_ = new_r_Or(block, c0, c1, mode_b);
				DBG_OPT_ALGSIM0(oldn, f1, FS_OPT_MUX_COMBINE);
				return new_r_Mux(block, or_, f1, t1, mode);
			} else if (t == f1) {
				/* Mux(cond0, x, Mux(cond1, y, x)) */
				ir_node* not_c1  = new_r_Not(block, c1, mode_b);
				ir_node* or_     = new_r_Or(block, c0, not_c1, mode_b);
				DBG_OPT_ALGSIM0(oldn, t1, FS_OPT_MUX_COMBINE);
				return new_r_Mux(block, or_, t1, f1, mode);
			}
		}

		/* note: after normalization, false can only happen on default */
		if (mode == mode_b) {
			dbg_info *dbg   = get_irn_dbg_info(n);
			ir_node  *block = get_nodes_block(n);

			if (is_Const(t)) {
				ir_tarval *tv_t = get_Const_tarval(t);
				if (tv_t == tarval_b_true) {
					if (is_Const(f)) {
						/* Muxb(sel, true, false) = sel */
						assert(get_Const_tarval(f) == tarval_b_false);
						DBG_OPT_ALGSIM0(oldn, sel, FS_OPT_MUX_BOOL);
						return sel;
					} else {
						/* Muxb(sel, true, x) = Or(sel, x) */
						n = new_rd_Or(dbg, block, sel, f, mode_b);
						DBG_OPT_ALGSIM0(oldn, n, FS_OPT_MUX_OR_BOOL);
						return n;
					}
				}
			} else if (is_Const(f)) {
				ir_tarval *tv_f = get_Const_tarval(f);
				if (tv_f == tarval_b_true) {
					/* Muxb(sel, x, true) = Or(Not(sel), x) */
					ir_node* not_sel = new_rd_Not(dbg, block, sel, mode_b);
					DBG_OPT_ALGSIM0(oldn, n, FS_OPT_MUX_ORNOT_BOOL);
					n = new_rd_Or(dbg, block, not_sel, t, mode_b);
					return n;
				} else {
					/* Muxb(sel, x, false) = And(sel, x) */
					assert(tv_f == tarval_b_false);
					n = new_rd_And(dbg, block, sel, t, mode_b);
					DBG_OPT_ALGSIM0(oldn, n, FS_OPT_MUX_AND_BOOL);
					return n;
				}
			}
		}
	}

	if (is_Cmp(sel) && mode_is_int(mode) && is_cmp_equality_zero(sel)) {
		ir_relation relation = get_Cmp_relation(sel);
		ir_node    *cmp_r    = get_Cmp_right(sel);
		ir_node    *cmp_l    = get_Cmp_left(sel);
		ir_node    *block    = get_nodes_block(n);

		if (is_And(cmp_l) && f == cmp_r) {
			ir_node *and_r = get_And_right(cmp_l);
			ir_node *and_l;

			if (and_r == t && is_single_bit(and_r)) {
				if (relation == ir_relation_equal) {
					/* Mux((a & (1<<n)) == 0, (1<<n), 0) == (a&(1<<n)) xor ((1<<n)) */
					n = new_rd_Eor(get_irn_dbg_info(n),
						block, cmp_l, t, mode);
					DBG_OPT_ALGSIM1(oldn, sel, sel, n, FS_OPT_MUX_TO_BITOP);
				} else {
					/* Mux((a & (1<<n)) != 0, (1<<n), 0) == a & (1<<n) */
					n = cmp_l;
					DBG_OPT_ALGSIM1(oldn, sel, sel, n, FS_OPT_MUX_TO_BITOP);
				}
				return n;
			}
			and_l = get_And_left(cmp_l);
			if (and_l == t && is_single_bit(and_l)) {
				if (relation == ir_relation_equal) {
					/* ((1 << n) & a) == 0, (1 << n), 0) */
					n = new_rd_Eor(get_irn_dbg_info(n),
						block, cmp_l, t, mode);
					DBG_OPT_ALGSIM1(oldn, sel, sel, n, FS_OPT_MUX_TO_BITOP);
				} else {
					/* ((1 << n) & a) != 0, (1 << n), 0) */
					n = cmp_l;
					DBG_OPT_ALGSIM1(oldn, sel, sel, n, FS_OPT_MUX_TO_BITOP);
				}
				return n;
			}
		}
	}

	return n;
}

/**
 * optimize Sync nodes that have other syncs as input we simply add the inputs
 * of the other sync to our own inputs
 */
static ir_node *transform_node_Sync(ir_node *n)
{
	int arity = get_Sync_n_preds(n);
	int i;

	for (i = 0; i < arity;) {
		ir_node *pred = get_Sync_pred(n, i);
		int      pred_arity;
		int      j;

		/* Remove Bad predecessors */
		if (is_Bad(pred)) {
			del_Sync_n(n, i);
			--arity;
			continue;
		}

		/* Remove duplicate predecessors */
		for (j = 0; j < i; ++j) {
			if (get_Sync_pred(n, j) == pred) {
				del_Sync_n(n, i);
				--arity;
				break;
			}
		}
		if (j < i)
			continue;

		if (!is_Sync(pred)) {
			++i;
			continue;
		}

		del_Sync_n(n, i);
		--arity;

		pred_arity = get_Sync_n_preds(pred);
		for (j = 0; j < pred_arity; ++j) {
			ir_node *pred_pred = get_Sync_pred(pred, j);
			int      k;

			for (k = 0;; ++k) {
				if (k >= arity) {
					add_irn_n(n, pred_pred);
					++arity;
					break;
				}
				if (get_Sync_pred(n, k) == pred_pred)
					break;
			}
		}
	}

	if (arity == 0) {
		ir_graph *irg = get_irn_irg(n);
		return new_r_Bad(irg, mode_M);
	}
	if (arity == 1) {
		return get_Sync_pred(n, 0);
	}

	/* rehash the sync node */
	add_identities(n);
	return n;
}

static ir_node *create_load_replacement_tuple(ir_node *n, ir_node *mem,
                                              ir_node *res)
{
	ir_node  *block = get_nodes_block(n);
	ir_graph *irg   = get_irn_irg(n);
	ir_node  *in[pn_Load_max+1];
	size_t    n_in  = 2;
	in[pn_Load_M]   = mem;
	in[pn_Load_res] = res;
	if (ir_throws_exception(n)) {
		in[pn_Load_X_regular] = new_r_Jmp(block);
		in[pn_Load_X_except]  = new_r_Bad(irg, mode_X);
		n_in                  = 4;
		assert(pn_Load_max == 4);
	}
	ir_node  *tuple = new_r_Tuple(block, n_in, in);
	return tuple;
}

static ir_node *transform_node_Load(ir_node *n)
{
	/* don't touch volatile loads */
	if (get_Load_volatility(n) == volatility_is_volatile)
		return n;

	ir_node *ptr = get_Load_ptr(n);
	const ir_node *confirm;
	if (value_not_zero(ptr, &confirm) && confirm == NULL) {
		set_irn_pinned(n, op_pin_state_floats);
	}

	/* if our memory predecessor is a load from the same address, then reuse the
	 * previous result */
	ir_node *mem = get_Load_mem(n);
	if (!is_Proj(mem))
		return n;
	ir_node *mem_pred = get_Proj_pred(mem);
	if (is_Load(mem_pred)) {
		ir_node *pred_load = mem_pred;

		/* conservatively compare the 2 loads. TODO: This could be less strict
		 * with fixup code in some situations (like smaller/bigger modes) */
		if (get_Load_ptr(pred_load) != ptr)
			return n;
		if (get_Load_mode(pred_load) != get_Load_mode(n))
			return n;
		/* all combinations of aligned/unaligned pred/n should be fine so we do
		 * not compare the unaligned attribute */
		ir_mode  *mode  = get_Load_mode(n);
		ir_node  *res   = new_r_Proj(pred_load, mode, pn_Load_res);
		return create_load_replacement_tuple(n, mem, res);
	} else if (is_Store(mem_pred)) {
		ir_node *pred_store = mem_pred;
		ir_node *value      = get_Store_value(pred_store);

		if (get_Store_ptr(pred_store) != ptr)
			return n;
		if (get_irn_mode(value) != get_Load_mode(n))
			return n;
		/* all combinations of aligned/unaligned pred/n should be fine so we do
		 * not compare the unaligned attribute */
		return create_load_replacement_tuple(n, mem, value);
	}

	return n;
}

static ir_node *transform_node_Store(ir_node *n)
{
	/* don't touch volatile stores */
	if (get_Store_volatility(n) == volatility_is_volatile)
		return n;

	ir_node *ptr = get_Store_ptr(n);
	const ir_node *confirm;
	if (value_not_zero(ptr, &confirm) && confirm == NULL) {
		set_irn_pinned(n, op_pin_state_floats);
	}
	return n;
}

/**
 * optimize a trampoline Call into a direct Call
 */
static ir_node *transform_node_Call(ir_node *call)
{
	ir_node  *callee = get_Call_ptr(call);
	ir_node  *adr, *mem, *res, *bl, **in;
	ir_type  *ctp, *mtp, *tp;
	ir_graph *irg;
	type_dbg_info *tdb;
	dbg_info *db;
	size_t   i, n_res, n_param;
	ir_variadicity var;

	if (! is_Proj(callee))
		return call;
	callee = get_Proj_pred(callee);
	if (! is_Builtin(callee))
		return call;
	if (get_Builtin_kind(callee) != ir_bk_inner_trampoline)
		return call;

	mem = get_Call_mem(call);

	if (skip_Proj(mem) == callee) {
		/* memory is routed to the trampoline, skip */
		mem = get_Builtin_mem(callee);
	}

	/* build a new call type */
	mtp = get_Call_type(call);
	tdb = get_type_dbg_info(mtp);

	n_res   = get_method_n_ress(mtp);
	n_param = get_method_n_params(mtp);
	ctp     = new_d_type_method(n_param + 1, n_res, tdb);

	for (i = 0; i < n_res; ++i)
		set_method_res_type(ctp, i, get_method_res_type(mtp, i));

	NEW_ARR_A(ir_node *, in, n_param + 1);

	/* FIXME: we don't need a new pointer type in every step */
	irg = get_irn_irg(call);
	tp = get_irg_frame_type(irg);
	tp = new_type_pointer(tp);
	set_method_param_type(ctp, 0, tp);

	in[0] = get_Builtin_param(callee, 2);
	for (i = 0; i < n_param; ++i) {
		set_method_param_type(ctp, i + 1, get_method_param_type(mtp, i));
		in[i + 1] = get_Call_param(call, i);
	}
	var = get_method_variadicity(mtp);
	set_method_variadicity(ctp, var);
	/* When we resolve a trampoline, the function must be called by a this-call */
	set_method_calling_convention(ctp, get_method_calling_convention(mtp) | cc_this_call);
	set_method_additional_properties(ctp, get_method_additional_properties(mtp));

	adr = get_Builtin_param(callee, 1);

	db  = get_irn_dbg_info(call);
	bl  = get_nodes_block(call);

	res = new_rd_Call(db, bl, mem, adr, n_param + 1, in, ctp);
	if (get_irn_pinned(call) == op_pin_state_floats)
		set_irn_pinned(res, op_pin_state_floats);
	return res;
}

/**
 * Tries several [inplace] [optimizing] transformations and returns an
 * equivalent node.  The difference to equivalent_node() is that these
 * transformations _do_ generate new nodes, and thus the old node must
 * not be freed even if the equivalent node isn't the old one.
 */
static ir_node *transform_node(ir_node *n)
{
	ir_node *old_n;
	unsigned iro;
restart:
	old_n = n;
	iro   = get_irn_opcode_(n);
	/* constant expression evaluation / constant folding */
	if (get_opt_constant_folding()) {
		/* neither constants nor Tuple values can be evaluated */
		if (iro != iro_Const && get_irn_mode(n) != mode_T) {
			/* try to evaluate */
			ir_tarval *tv = computed_value(n);
			if (tv != tarval_bad) {
				/* evaluation was successful -- replace the node. */
				ir_graph *irg = get_irn_irg(n);

				n = new_r_Const(irg, tv);

				DBG_OPT_CSTEVAL(old_n, n);
				return n;
			}
		}
	}

	/* remove unnecessary nodes */
	if (get_opt_constant_folding() ||
		(iro == iro_Phi)  ||   /* always optimize these nodes. */
		(iro == iro_Id)   ||   /* ... */
		(iro == iro_Proj) ||   /* ... */
		(iro == iro_Block)) {  /* Flags tested local. */
		n = equivalent_node(n);
		if (n != old_n)
			goto restart;
	}

	/* Some more constant expression evaluation. */
	if (get_opt_algebraic_simplification() ||
		(iro == iro_Cond) ||
		(iro == iro_Proj)) {    /* Flags tested local. */
		if (n->op->ops.transform_node != NULL) {
			n = n->op->ops.transform_node(n);
			if (n != old_n) {
				goto restart;
			}
		}
	}

	return n;
}

static void register_computed_value_func(ir_op *op, computed_value_func func)
{
	assert(op->ops.computed_value == NULL || op->ops.computed_value == func);
	op->ops.computed_value = func;
}

static void register_computed_value_func_proj(ir_op *op,
                                              computed_value_func func)
{
	assert(op->ops.computed_value_Proj == NULL
	    || op->ops.computed_value_Proj == func);
	op->ops.computed_value_Proj = func;
}

static void register_equivalent_node_func(ir_op *op, equivalent_node_func func)
{
	assert(op->ops.equivalent_node == NULL || op->ops.equivalent_node == func);
	op->ops.equivalent_node = func;
}

static void register_equivalent_node_func_proj(ir_op *op,
                                               equivalent_node_func func)
{
	assert(op->ops.equivalent_node_Proj == NULL
	    || op->ops.equivalent_node_Proj == func);
	op->ops.equivalent_node_Proj = func;
}

static void register_transform_node_func(ir_op *op, transform_node_func func)
{
	assert(op->ops.transform_node == NULL || op->ops.transform_node == func);
	op->ops.transform_node = func;
}

static void register_transform_node_func_proj(ir_op *op,
                                              transform_node_func func)
{
	assert(op->ops.transform_node_Proj == NULL
	    || op->ops.transform_node_Proj == func);
	op->ops.transform_node_Proj = func;
}

void ir_register_opt_node_ops(void)
{
	register_computed_value_func(op_Add,      computed_value_Add);
	register_computed_value_func(op_And,      computed_value_And);
	register_computed_value_func(op_Borrow,   computed_value_Borrow);
	register_computed_value_func(op_Carry,    computed_value_Carry);
	register_computed_value_func(op_Cmp,      computed_value_Cmp);
	register_computed_value_func(op_Confirm,  computed_value_Confirm);
	register_computed_value_func(op_Const,    computed_value_Const);
	register_computed_value_func(op_Conv,     computed_value_Conv);
	register_computed_value_func(op_Eor,      computed_value_Eor);
	register_computed_value_func(op_Minus,    computed_value_Minus);
	register_computed_value_func(op_Mul,      computed_value_Mul);
	register_computed_value_func(op_Mux,      computed_value_Mux);
	register_computed_value_func(op_Not,      computed_value_Not);
	register_computed_value_func(op_Or,       computed_value_Or);
	register_computed_value_func(op_Proj,     computed_value_Proj);
	register_computed_value_func(op_Rotl,     computed_value_Rotl);
	register_computed_value_func(op_Shl,      computed_value_Shl);
	register_computed_value_func(op_Shr,      computed_value_Shr);
	register_computed_value_func(op_Shrs,     computed_value_Shrs);
	register_computed_value_func(op_Sub,      computed_value_Sub);
	register_computed_value_func(op_SymConst, computed_value_SymConst);
	register_computed_value_func_proj(op_Div, computed_value_Proj_Div);
	register_computed_value_func_proj(op_Mod, computed_value_Proj_Mod);

	register_equivalent_node_func(op_Add,     equivalent_node_Add);
	register_equivalent_node_func(op_And,     equivalent_node_And);
	register_equivalent_node_func(op_Confirm, equivalent_node_Confirm);
	register_equivalent_node_func(op_Conv,    equivalent_node_Conv);
	register_equivalent_node_func(op_Eor,     equivalent_node_Eor);
	register_equivalent_node_func(op_Id,      equivalent_node_Id);
	register_equivalent_node_func(op_Minus,   equivalent_node_involution);
	register_equivalent_node_func(op_Mul,     equivalent_node_Mul);
	register_equivalent_node_func(op_Mux,     equivalent_node_Mux);
	register_equivalent_node_func(op_Not,     equivalent_node_involution);
	register_equivalent_node_func(op_Or,      equivalent_node_Or);
	register_equivalent_node_func(op_Phi,     equivalent_node_Phi);
	register_equivalent_node_func(op_Proj,    equivalent_node_Proj);
	register_equivalent_node_func(op_Rotl,    equivalent_node_left_zero);
	register_equivalent_node_func(op_Shl,     equivalent_node_left_zero);
	register_equivalent_node_func(op_Shr,     equivalent_node_left_zero);
	register_equivalent_node_func(op_Shrs,    equivalent_node_left_zero);
	register_equivalent_node_func(op_Sub,     equivalent_node_Sub);
	register_equivalent_node_func_proj(op_Bound, equivalent_node_Proj_Bound);
	register_equivalent_node_func_proj(op_CopyB, equivalent_node_Proj_CopyB);
	register_equivalent_node_func_proj(op_Div,   equivalent_node_Proj_Div);
	register_equivalent_node_func_proj(op_Tuple, equivalent_node_Proj_Tuple);

	register_transform_node_func(op_Add,    transform_node_Add);
	register_transform_node_func(op_And,    transform_node_And);
	register_transform_node_func(op_Block,  transform_node_Block);
	register_transform_node_func(op_Call,   transform_node_Call);
	register_transform_node_func(op_Cmp,    transform_node_Cmp);
	register_transform_node_func(op_Cond,   transform_node_Cond);
	register_transform_node_func(op_Conv,   transform_node_Conv);
	register_transform_node_func(op_Div,    transform_node_Div);
	register_transform_node_func(op_End,    transform_node_End);
	register_transform_node_func(op_Eor,    transform_node_Eor);
	register_transform_node_func(op_Load,   transform_node_Load);
	register_transform_node_func(op_Minus,  transform_node_Minus);
	register_transform_node_func(op_Mod,    transform_node_Mod);
	register_transform_node_func(op_Mul,    transform_node_Mul);
	register_transform_node_func(op_Mux,    transform_node_Mux);
	register_transform_node_func(op_Not,    transform_node_Not);
	register_transform_node_func(op_Or,     transform_node_Or);
	register_transform_node_func(op_Phi,    transform_node_Phi);
	register_transform_node_func(op_Proj,   transform_node_Proj);
	register_transform_node_func(op_Rotl,   transform_node_Rotl);
	register_transform_node_func(op_Shl,    transform_node_Shl);
	register_transform_node_func(op_Shrs,   transform_node_Shrs);
	register_transform_node_func(op_Shr,    transform_node_Shr);
	register_transform_node_func(op_Store,  transform_node_Store);
	register_transform_node_func(op_Sub,    transform_node_Sub);
	register_transform_node_func(op_Switch, transform_node_Switch);
	register_transform_node_func(op_Sync,   transform_node_Sync);
	register_transform_node_func_proj(op_Bound, transform_node_Proj_Bound);
	register_transform_node_func_proj(op_CopyB, transform_node_Proj_CopyB);
	register_transform_node_func_proj(op_Div,   transform_node_Proj_Div);
	register_transform_node_func_proj(op_Load,  transform_node_Proj_Load);
	register_transform_node_func_proj(op_Mod,   transform_node_Proj_Mod);
	register_transform_node_func_proj(op_Store, transform_node_Proj_Store);
}

/* **************** Common Subexpression Elimination **************** */

/** The size of the hash table used, should estimate the number of nodes
    in a graph. */
#define N_IR_NODES 512

int identities_cmp(const void *elt, const void *key)
{
	ir_node *a = (ir_node *)elt;
	ir_node *b = (ir_node *)key;
	int i, irn_arity_a;

	if (a == b) return 0;

	if ((get_irn_op(a) != get_irn_op(b)) ||
	    (get_irn_mode(a) != get_irn_mode(b))) return 1;

	/* compare if a's in and b's in are of equal length */
	irn_arity_a = get_irn_arity(a);
	if (irn_arity_a != get_irn_arity(b))
		return 1;

	/* blocks are never the same */
	if (is_Block(a))
		return 1;

	if (get_irn_pinned(a) == op_pin_state_pinned) {
		/* for pinned nodes, the block inputs must be equal */
		if (get_nodes_block(a) != get_nodes_block(b))
			return 1;
	} else {
		ir_node *block_a = get_nodes_block(a);
		ir_node *block_b = get_nodes_block(b);
		if (! get_opt_global_cse()) {
			/* for block-local CSE both nodes must be in the same Block */
			if (block_a != block_b)
				return 1;
		} else {
			/* The optimistic approach would be to do nothing here.
			 * However doing GCSE optimistically produces a lot of partially dead code which appears
			 * to be worse in practice than the missed opportunities.
			 * So we use a very conservative variant here and only CSE if 1 value dominates the
			 * other. */
			if (!block_dominates(block_a, block_b)
			    && !block_dominates(block_b, block_a))
			    return 1;
			/* respect the workaround rule: do not move nodes which are only
			 * held by keepalive edges */
			if (only_used_by_keepalive(a) || only_used_by_keepalive(b))
				return 1;
		}
	}

	/* compare a->in[0..ins] with b->in[0..ins] */
	for (i = 0; i < irn_arity_a; ++i) {
		ir_node *pred_a = get_irn_n(a, i);
		ir_node *pred_b = get_irn_n(b, i);
		if (pred_a != pred_b) {
			/* if both predecessors are CSE neutral they might be different */
			if (!is_irn_cse_neutral(pred_a) || !is_irn_cse_neutral(pred_b))
				return 1;
		}
	}

	/*
	 * here, we already now that the nodes are identical except their
	 * attributes
	 */
	if (a->op->ops.node_cmp_attr)
		return a->op->ops.node_cmp_attr(a, b);

	return 0;
}

unsigned ir_node_hash(const ir_node *node)
{
	return node->op->ops.hash(node);
}

void new_identities(ir_graph *irg)
{
	if (irg->value_table != NULL)
		del_pset(irg->value_table);
	irg->value_table = new_pset(identities_cmp, N_IR_NODES);
}

void del_identities(ir_graph *irg)
{
	if (irg->value_table != NULL)
		del_pset(irg->value_table);
}

static int cmp_node_nr(const void *a, const void *b)
{
	ir_node **p1 = (ir_node**)a;
	ir_node **p2 = (ir_node**)b;
	long      n1 = get_irn_node_nr(*p1);
	long      n2 = get_irn_node_nr(*p2);
	return (n1>n2) - (n1<n2);
}

void ir_normalize_node(ir_node *n)
{
	if (is_op_commutative(get_irn_op(n))) {
		ir_node *l = get_binop_left(n);
		ir_node *r = get_binop_right(n);

		/* For commutative operators perform  a OP b == b OP a but keep
		 * constants on the RIGHT side. This helps greatly in some
		 * optimizations.  Moreover we use the idx number to make the form
		 * deterministic. */
		if (!operands_are_normalized(l, r)) {
			set_binop_left(n, r);
			set_binop_right(n, l);
			hook_normalize(n);
		}
	} else if (is_Sync(n)) {
		/* we assume that most of the time the inputs of a Sync node are already
		 * sorted, so check this first as a shortcut */
		bool           ins_sorted = true;
		int            arity      = get_irn_arity(n);
		const ir_node *last       = get_irn_n(n, 0);
		int      i;
		for (i = 1; i < arity; ++i) {
			const ir_node *node = get_irn_n(n, i);
			if (get_irn_node_nr(node) < get_irn_node_nr(last)) {
				ins_sorted = false;
				break;
			}
			last = node;
		}

		if (!ins_sorted) {
			ir_node **ins     = get_irn_in(n)+1;
			ir_node **new_ins = XMALLOCN(ir_node*, arity);
			memcpy(new_ins, ins, arity*sizeof(ins[0]));
			qsort(new_ins, arity, sizeof(new_ins[0]), cmp_node_nr);
			set_irn_in(n, arity, new_ins);
			xfree(new_ins);
		}
	}
}

ir_node *identify_remember(ir_node *n)
{
	ir_graph *irg         = get_irn_irg(n);
	pset     *value_table = irg->value_table;
	ir_node  *nn;

	if (value_table == NULL)
		return n;

	ir_normalize_node(n);
	/* lookup or insert in hash table with given hash key. */
	nn = (ir_node*)pset_insert(value_table, n, ir_node_hash(n));

	if (nn != n) {
		/* n is reachable again */
		edges_node_revival(nn);
	}

	return nn;
}

/**
 * During construction we set the op_pin_state_pinned flag in the graph right
 * when the optimization is performed.  The flag turning on procedure global
 * cse could be changed between two allocations.  This way we are safe.
 *
 * @param n            The node to lookup
 */
static inline ir_node *identify_cons(ir_node *n)
{
	ir_node *old = n;

	n = identify_remember(n);
	if (n != old && get_nodes_block(old) != get_nodes_block(n)) {
		ir_graph *irg = get_irn_irg(n);
		set_irg_pinned(irg, op_pin_state_floats);
	}
	return n;
}

void add_identities(ir_node *node)
{
	if (!get_opt_cse())
		return;
	if (is_Block(node))
		return;

	identify_remember(node);
}

void visit_all_identities(ir_graph *irg, irg_walk_func visit, void *env)
{
	ir_graph *rem = current_ir_graph;

	current_ir_graph = irg;
	foreach_pset(irg->value_table, ir_node, node) {
		visit(node, env);
	}
	current_ir_graph = rem;
}

ir_node *optimize_node(ir_node *n)
{
	ir_node   *oldn = n;
	ir_graph  *irg  = get_irn_irg(n);
	unsigned   iro  = get_irn_opcode(n);
	ir_tarval *tv;

	/* Always optimize Phi nodes: part of the construction. */
	if ((!get_opt_optimize()) && (iro != iro_Phi)) return n;

	/* constant expression evaluation / constant folding */
	if (get_opt_constant_folding()) {
		/* neither constants nor Tuple values can be evaluated */
		if (iro != iro_Const && (get_irn_mode(n) != mode_T)) {
			/* try to evaluate */
			tv = computed_value(n);
			if (tv != tarval_bad) {
				ir_node *nw;
				size_t node_size;

				/*
				 * we MUST copy the node here temporarily, because it's still
				 * needed for DBG_OPT_CSTEVAL
				 */
				node_size = offsetof(ir_node, attr) +  n->op->attr_size;
				oldn = (ir_node*)alloca(node_size);

				memcpy(oldn, n, node_size);
				CLONE_ARR_A(ir_node *, oldn->in, n->in);

				/* ARG, copy the in array, we need it for statistics */
				memcpy(oldn->in, n->in, ARR_LEN(n->in) * sizeof(n->in[0]));

				/* note the inplace edges module */
				edges_node_deleted(n);

				/* evaluation was successful -- replace the node. */
				irg_kill_node(irg, n);
				nw = new_r_Const(irg, tv);

				DBG_OPT_CSTEVAL(oldn, nw);
				return nw;
			}
		}
	}

	/* remove unnecessary nodes */
	if (get_opt_algebraic_simplification() ||
	    (iro == iro_Phi)  ||   /* always optimize these nodes. */
	    (iro == iro_Id)   ||
	    (iro == iro_Proj) ||
	    (iro == iro_Block)  )  /* Flags tested local. */
		n = equivalent_node(n);

	/* Common Subexpression Elimination.
	 *
	 * Checks whether n is already available.
	 * The block input is used to distinguish different subexpressions. Right
	 * now all nodes are op_pin_state_pinned to blocks, i.e., the CSE only finds common
	 * subexpressions within a block.
	 */
	if (get_opt_cse())
		n = identify_cons(n);

	if (n != oldn) {
		edges_node_deleted(oldn);

		/* We found an existing, better node, so we can deallocate the old node. */
		irg_kill_node(irg, oldn);
		return n;
	}

	/* Some more constant expression evaluation that does not allow to
	   free the node. */
	iro = get_irn_opcode(n);
	if (get_opt_algebraic_simplification() ||
		(iro == iro_Cond) ||
		(iro == iro_Proj)) {    /* Flags tested local. */
		n = transform_node(n);
	}

	/* Now we have a legal, useful node. Enter it in hash table for CSE */
	if (get_opt_cse()) {
		ir_node *o = n;
		n = identify_remember(o);
		if (o != n)
			DBG_OPT_CSE(o, n);
	}

	return n;
}

ir_node *optimize_in_place_2(ir_node *n)
{
	if (!get_opt_optimize() && !is_Phi(n)) return n;

	if (is_Deleted(n))
		return n;

	/** common subexpression elimination **/
	/* Checks whether n is already available. */
	/* The block input is used to distinguish different subexpressions.
	 * Right now all nodes are op_pin_state_pinned to blocks, i.e., the cse
	 * only finds common subexpressions within a block. */
	if (get_opt_cse()) {
		ir_node *o = n;
		n = identify_remember(n);
		if (n != o) {
			DBG_OPT_CSE(o, n);
			/* we have another existing node now, we do not optimize it here */
			return n;
		}
	}

	n = transform_node(n);

	/* Now we can verify the node, as it has no dead inputs any more. */
	irn_verify(n);

	/* Now we have a legal, useful node. Enter it in hash table for cse.
	 *
	 * Note: This is only necessary because some of the optimisations
	 * operate in-place (set_XXX_bla, turn_into_tuple, ...) which is considered
	 * bad practice and should be fixed sometime.
	 */
	if (get_opt_cse()) {
		ir_node *o = n;
		n = identify_remember(o);
		if (o != n)
			DBG_OPT_CSE(o, n);
	}

	return n;
}

ir_node *optimize_in_place(ir_node *n)
{
	ir_graph *irg = get_irn_irg(n);

	if (get_opt_global_cse())
		set_irg_pinned(irg, op_pin_state_floats);

	/* FIXME: Maybe we could also test whether optimizing the node can
	   change the control graph. */
	clear_irg_properties(irg, IR_GRAPH_PROPERTY_CONSISTENT_DOMINANCE);
	return optimize_in_place_2(n);
}