ia32_emitter.c

/*
 * Copyright (C) 1995-2007 University of Karlsruhe.  All right reserved.
 *
 * This file is part of libFirm.
 *
 * This file may be distributed and/or modified under the terms of the
 * GNU General Public License version 2 as published by the Free Software
 * Foundation and appearing in the file LICENSE.GPL included in the
 * packaging of this file.
 *
 * 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       This file implements the ia32 node emitter.
 * @author      Christian Wuerdig, Matthias Braun
 * @version     $Id$
 */
#ifdef HAVE_CONFIG_H
#include "config.h"
#endif

#include <limits.h>

#include "xmalloc.h"
#include "tv.h"
#include "iredges.h"
#include "debug.h"
#include "irgwalk.h"
#include "irprintf.h"
#include "irop_t.h"
#include "irargs_t.h"
#include "irprog_t.h"
#include "iredges_t.h"
#include "execfreq.h"
#include "error.h"
#include "raw_bitset.h"

#include "../besched_t.h"
#include "../benode_t.h"
#include "../beabi.h"
#include "../be_dbgout.h"
#include "../beemitter.h"
#include "../begnuas.h"
#include "../beirg_t.h"

#include "ia32_emitter.h"
#include "gen_ia32_emitter.h"
#include "gen_ia32_regalloc_if.h"
#include "ia32_nodes_attr.h"
#include "ia32_new_nodes.h"
#include "ia32_map_regs.h"
#include "bearch_ia32_t.h"

DEBUG_ONLY(static firm_dbg_module_t *dbg = NULL;)

#define BLOCK_PREFIX ".L"

#define SNPRINTF_BUF_LEN 128

/**
 * Returns the register at in position pos.
 */
static
const arch_register_t *get_in_reg(ia32_emit_env_t *env, const ir_node *irn,
                                  int pos)
{
	const arch_env_t       *arch_env = env->arch_env;
	ir_node                *op;
	const arch_register_t  *reg = NULL;

	assert(get_irn_arity(irn) > pos && "Invalid IN position");

	/* The out register of the operator at position pos is the
	   in register we need. */
	op = get_irn_n(irn, pos);

	reg = arch_get_irn_register(arch_env, op);

	assert(reg && "no in register found");

	if(reg == &ia32_gp_regs[REG_GP_NOREG])
		panic("trying to emit noreg");

	/* in case of unknown register: just return a valid register */
	if (reg == &ia32_gp_regs[REG_GP_UKNWN]) {
		const arch_register_req_t *req;

		/* ask for the requirements */
		req = arch_get_register_req(arch_env, irn, pos);

		if (arch_register_req_is(req, limited)) {
			/* in case of limited requirements: get the first allowed register */
			unsigned idx = rbitset_next(req->limited, 0, 1);
			reg = arch_register_for_index(req->cls, idx);
		} else {
			/* otherwise get first register in class */
			reg = arch_register_for_index(req->cls, 0);
		}
	}

	return reg;
}

/**
 * Returns the register at out position pos.
 */
static
const arch_register_t *get_out_reg(ia32_emit_env_t *env, const ir_node *irn,
                                   int pos)
{
	const arch_env_t      *arch_env = env->arch_env;
	ir_node               *proj;
	const arch_register_t *reg = NULL;

	/* 1st case: irn is not of mode_T, so it has only                 */
	/*           one OUT register -> good                             */
	/* 2nd case: irn is of mode_T -> collect all Projs and ask the    */
	/*           Proj with the corresponding projnum for the register */

	if (get_irn_mode(irn) != mode_T) {
		reg = arch_get_irn_register(arch_env, irn);
	} else if (is_ia32_irn(irn)) {
		reg = get_ia32_out_reg(irn, pos);
	} else {
		const ir_edge_t *edge;

		foreach_out_edge(irn, edge) {
			proj = get_edge_src_irn(edge);
			assert(is_Proj(proj) && "non-Proj from mode_T node");
			if (get_Proj_proj(proj) == pos) {
				reg = arch_get_irn_register(arch_env, proj);
				break;
			}
		}
	}

	assert(reg && "no out register found");
	return reg;
}

/**
 * Determine the gnu assembler suffix that indicates a mode
 */
static
char get_mode_suffix(const ir_mode *mode) {
	if(mode_is_float(mode)) {
		switch(get_mode_size_bits(mode)) {
		case 32:
			return 's';
		case 64:
			return 'l';
		case 80:
		case 96:
			return 't';
		}
	} else {
		assert(mode_is_int(mode) || mode_is_reference(mode));
		switch(get_mode_size_bits(mode)) {
		case 64:
			return 'q';
		case 32:
			return 'l';
		case 16:
			return 'w';
		case 8:
			return 'b';
		}
	}
	panic("Can't output mode_suffix for %+F\n", mode);
}

static
int produces_result(const ir_node *node) {
	return
		!is_ia32_CmpSet(node)    &&
		!is_ia32_CondJmp(node)   &&
		!is_ia32_St(node)        &&
		!is_ia32_SwitchJmp(node) &&
		!is_ia32_TestJmp(node)   &&
		!is_ia32_xCmpSet(node)   &&
		!is_ia32_xCondJmp(node)  &&
		!is_ia32_CmpCMov(node)   &&
		!is_ia32_TestCMov(node)  &&
		!is_ia32_CmpSet(node)    && /* this is correct, the Cmp has no result */
		!is_ia32_TestSet(node);
}

static
const char *ia32_get_reg_name_for_mode(ia32_emit_env_t *env, ir_mode *mode,
                                       const arch_register_t *reg) {
	switch(get_mode_size_bits(mode)) {
		case 8:
			return ia32_get_mapped_reg_name(env->isa->regs_8bit, reg);
		case 16:
			return ia32_get_mapped_reg_name(env->isa->regs_16bit, reg);
		default:
			return (char *)arch_register_get_name(reg);
	}
}

/**
 * Add a number to a prefix. This number will not be used a second time.
 */
static
char *get_unique_label(char *buf, size_t buflen, const char *prefix) {
	static unsigned long id = 0;
	snprintf(buf, buflen, "%s%lu", prefix, ++id);
	return buf;
}

/*************************************************************
 *             _       _    __   _          _
 *            (_)     | |  / _| | |        | |
 *  _ __  _ __ _ _ __ | |_| |_  | |__   ___| |_ __   ___ _ __
 * | '_ \| '__| | '_ \| __|  _| | '_ \ / _ \ | '_ \ / _ \ '__|
 * | |_) | |  | | | | | |_| |   | | | |  __/ | |_) |  __/ |
 * | .__/|_|  |_|_| |_|\__|_|   |_| |_|\___|_| .__/ \___|_|
 * | |                                       | |
 * |_|                                       |_|
 *************************************************************/

// we have no C++ and can't define an implicit ia32_emit_env_t* cast to
// be_emit_env_t* so we cheat a bit...
#define be_emit_char(env,c)             be_emit_char(env->emit,c)
#define be_emit_string(env,s)           be_emit_string(env->emit,s)
#undef be_emit_cstring
#define be_emit_cstring(env,x)          { be_emit_string_len(env->emit, x, sizeof(x)-1); }
#define be_emit_ident(env,i)            be_emit_ident(env->emit,i)
#define be_emit_tarval(env,tv)          be_emit_tarval(env->emit,tv)
#define be_emit_write_line(env)         be_emit_write_line(env->emit)
#define be_emit_finish_line_gas(env,n)  be_emit_finish_line_gas(env->emit,n)
#define be_emit_pad_comment(env)        be_emit_pad_comment(env->emit)

void ia32_emit_source_register(ia32_emit_env_t *env, const ir_node *node, int pos)
{
	const arch_register_t *reg = get_in_reg(env, node, pos);
	const char *reg_name = arch_register_get_name(reg);

	assert(pos < get_irn_arity(node));

	be_emit_char(env, '%');
	be_emit_string(env, reg_name);
}

void ia32_emit_8bit_source_register(ia32_emit_env_t *env, const ir_node *node, int pos)
{
	const arch_register_t *reg = get_in_reg(env, node, pos);
	const char *reg_name = arch_register_get_name(reg);

	assert(pos < get_irn_arity(node));

	be_emit_char(env, '%');
	be_emit_char(env, reg_name[1]);
	be_emit_char(env, 'l');
}

void ia32_emit_16bit_source_register(ia32_emit_env_t *env, const ir_node *node, int pos)
{
	const arch_register_t *reg = get_in_reg(env, node, pos);
	const char *reg_name = arch_register_get_name(reg);

	assert(pos < get_irn_arity(node));

	be_emit_char(env, '%');
	be_emit_string(env, &reg_name[1]);
}

void ia32_emit_dest_register(ia32_emit_env_t *env, const ir_node *node, int pos) {
	const arch_register_t *reg = get_out_reg(env, node, pos);
	const char *reg_name = arch_register_get_name(reg);

	be_emit_char(env, '%');
	be_emit_string(env, reg_name);
}

static void ia32_emit_register(ia32_emit_env_t *env, const arch_register_t *reg)
{
	const char *reg_name = arch_register_get_name(reg);

	be_emit_char(env, '%');
	be_emit_string(env, reg_name);
}

void ia32_emit_x87_name(ia32_emit_env_t *env, const ir_node *node, int pos)
{
	const ia32_x87_attr_t *attr = get_ia32_x87_attr_const(node);

	assert(pos < 3);
	be_emit_char(env, '%');
	be_emit_string(env, attr->x87[pos]->name);
}

void ia32_emit_immediate(ia32_emit_env_t *env, const ir_node *node)
{
	tarval *tv;
	ir_entity *ent;
	ident *id;

	be_emit_char(env, '$');

	switch(get_ia32_immop_type(node)) {
	case ia32_ImmConst:
		tv = get_ia32_Immop_tarval(node);
		be_emit_tarval(env, tv);
		return;
	case ia32_ImmSymConst:
		ent = get_ia32_Immop_symconst(node);
		set_entity_backend_marked(ent, 1);
		id = get_entity_ld_ident(ent);
		be_emit_ident(env, id);
		return;
	case ia32_ImmNone:
		break;
	}

	assert(0);
	be_emit_string(env, "BAD");
	return;
}

static
void ia32_emit_mode_suffix_mode(ia32_emit_env_t *env, const ir_mode *mode)
{
	be_emit_char(env, get_mode_suffix(mode));
}

void ia32_emit_mode_suffix(ia32_emit_env_t *env, const ir_node *node)
{
	ir_mode *mode = get_ia32_ls_mode(node);
	if(mode == NULL)
		mode = mode_Iu;

	ia32_emit_mode_suffix_mode(env, mode);
}

void ia32_emit_x87_mode_suffix(ia32_emit_env_t *env, const ir_node *node)
{
	ir_mode *mode = get_ia32_ls_mode(node);
	if(mode != NULL)
		ia32_emit_mode_suffix_mode(env, mode);
}

static
char get_xmm_mode_suffix(ir_mode *mode)
{
	assert(mode_is_float(mode));
	switch(get_mode_size_bits(mode)) {
	case 32:
		return 's';
	case 64:
		return 'd';
	default:
		assert(0);
	}
	return '%';
}

void ia32_emit_xmm_mode_suffix(ia32_emit_env_t *env, const ir_node *node)
{
	ir_mode *mode = get_ia32_ls_mode(node);
	assert(mode != NULL);
	be_emit_char(env, 's');
	be_emit_char(env, get_xmm_mode_suffix(mode));
}

void ia32_emit_xmm_mode_suffix_s(ia32_emit_env_t *env, const ir_node *node)
{
	ir_mode *mode = get_ia32_ls_mode(node);
	assert(mode != NULL);
	be_emit_char(env, get_xmm_mode_suffix(mode));
}

void ia32_emit_extend_suffix(ia32_emit_env_t *env, const ir_mode *mode)
{
	if(get_mode_size_bits(mode) == 32)
		return;
	if(mode_is_signed(mode)) {
		be_emit_char(env, 's');
	} else {
		be_emit_char(env, 'z');
	}
}

static
void ia32_emit_function_object(ia32_emit_env_t *env, const char *name)
{
	switch (be_gas_flavour) {
	case GAS_FLAVOUR_NORMAL:
		be_emit_cstring(env, "\t.type\t");
		be_emit_string(env, name);
		be_emit_cstring(env, ", @function\n");
		be_emit_write_line(env);
		break;
	case GAS_FLAVOUR_MINGW:
		be_emit_cstring(env, "\t.def\t");
		be_emit_string(env, name);
		be_emit_cstring(env, ";\t.scl\t2;\t.type\t32;\t.endef\n");
		be_emit_write_line(env);
		break;
	default:
		break;
	}
}

static
void ia32_emit_function_size(ia32_emit_env_t *env, const char *name)
{
	switch (be_gas_flavour) {
	case GAS_FLAVOUR_NORMAL:
		be_emit_cstring(env, "\t.size\t");
		be_emit_string(env, name);
		be_emit_cstring(env, ", .-");
		be_emit_string(env, name);
		be_emit_char(env, '\n');
		be_emit_write_line(env);
		break;
	default:
		break;
	}
}


static
void emit_ia32_Immediate(ia32_emit_env_t *env, const ir_node *node);

/**
 * Emits registers and/or address mode of a binary operation.
 */
void ia32_emit_binop(ia32_emit_env_t *env, const ir_node *node) {
	int            right_pos;
	const ir_node *right_op = get_irn_n(node, 3);

	switch(get_ia32_op_type(node)) {
	case ia32_Normal:
		if(is_ia32_Immediate(right_op)) {
			emit_ia32_Immediate(env, right_op);
			be_emit_cstring(env, ", ");
			ia32_emit_source_register(env, node, 2);
			break;
		} else if (is_ia32_ImmConst(node) || is_ia32_ImmSymConst(node)) {
			ia32_emit_immediate(env, node);
			be_emit_cstring(env, ", ");
			ia32_emit_source_register(env, node, 2);
		} else {
			const arch_register_t *in1 = get_in_reg(env, node, 2);
			const arch_register_t *in2 = get_in_reg(env, node, 3);
			const arch_register_t *out = produces_result(node) ? get_out_reg(env, node, 0) : NULL;
			const arch_register_t *in;
			const char            *in_name;

			in      = out ? ((out == in2) ? in1 : in2) : in2;
			out     = out ? out : in1;
			in_name = arch_register_get_name(in);

			if (is_ia32_emit_cl(node)) {
				assert(in == &ia32_gp_regs[REG_ECX]);
				in_name = "cl";
			}

			be_emit_char(env, '%');
			be_emit_string(env, in_name);
			be_emit_cstring(env, ", %");
			be_emit_string(env, arch_register_get_name(out));
		}
		break;
	case ia32_AddrModeS:
		if (is_ia32_ImmConst(node) || is_ia32_ImmSymConst(node)) {
			assert(!produces_result(node) &&
					"Source AM with Const must not produce result");
			ia32_emit_immediate(env, node);
			be_emit_cstring(env, ", ");
			ia32_emit_am(env, node);
		} else if(is_ia32_Immediate(right_op)) {
			assert(!produces_result(node) &&
					"Source AM with Const must not produce result");

			emit_ia32_Immediate(env, right_op);
			be_emit_cstring(env, ", ");
			ia32_emit_am(env, node);
		} else if (produces_result(node)) {
			ia32_emit_am(env, node);
			be_emit_cstring(env, ", ");
			ia32_emit_dest_register(env, node, 0);
		} else {
			ia32_emit_am(env, node);
			be_emit_cstring(env, ", ");
			ia32_emit_source_register(env, node, 2);
		}
		break;
	case ia32_AddrModeD:
		right_pos = get_irn_arity(node) >= 5 ? 3 : 2;
		right_op  = get_irn_n(node, right_pos);
		if(is_ia32_Immediate(right_op)) {
			emit_ia32_Immediate(env, right_op);
			be_emit_cstring(env, ", ");
			ia32_emit_am(env, node);
			break;
		} else if (is_ia32_ImmConst(node) || is_ia32_ImmSymConst(node)) {
			ia32_emit_immediate(env, node);
			be_emit_cstring(env, ", ");
			ia32_emit_am(env, node);
		} else {
			const arch_register_t *in1 = get_in_reg(env, node, right_pos);
			ir_mode               *mode = get_ia32_ls_mode(node);
			const char            *in_name;

			in_name = ia32_get_reg_name_for_mode(env, mode, in1);

			if (is_ia32_emit_cl(node)) {
				assert(in1 == &ia32_gp_regs[REG_ECX]);
				in_name = "cl";
			}

			be_emit_char(env, '%');
			be_emit_string(env, in_name);
			be_emit_cstring(env, ", ");
			ia32_emit_am(env, node);
		}
		break;
	default:
		assert(0 && "unsupported op type");
	}
}

/**
 * Emits registers and/or address mode of a binary operation.
 */
void ia32_emit_x87_binop(ia32_emit_env_t *env, const ir_node *node) {
	switch(get_ia32_op_type(node)) {
		case ia32_Normal:
			if (is_ia32_ImmConst(node) || is_ia32_ImmSymConst(node)) {
				// should not happen...
				assert(0);
			} else {
				const ia32_x87_attr_t *x87_attr = get_ia32_x87_attr_const(node);
				const arch_register_t *in1      = x87_attr->x87[0];
				const arch_register_t *in2      = x87_attr->x87[1];
				const arch_register_t *out      = x87_attr->x87[2];
				const arch_register_t *in;

				in  = out ? ((out == in2) ? in1 : in2) : in2;
				out = out ? out : in1;

				be_emit_char(env, '%');
				be_emit_string(env, arch_register_get_name(in));
				be_emit_cstring(env, ", %");
				be_emit_string(env, arch_register_get_name(out));
			}
			break;
		case ia32_AddrModeS:
		case ia32_AddrModeD:
			ia32_emit_am(env, node);
			break;
		default:
			assert(0 && "unsupported op type");
	}
}

void ia32_emit_am_or_dest_register(ia32_emit_env_t *env, const ir_node *node,
                                   int pos) {
	if(get_ia32_op_type(node) == ia32_Normal) {
		ia32_emit_dest_register(env, node, pos);
	} else {
		assert(get_ia32_op_type(node) == ia32_AddrModeD);
		ia32_emit_am(env, node);
	}
}

/**
 * Emits registers and/or address mode of a unary operation.
 */
void ia32_emit_unop(ia32_emit_env_t *env, const ir_node *node, int pos) {
	const ir_node *op;

	switch(get_ia32_op_type(node)) {
	case ia32_Normal:
		op = get_irn_n(node, pos);
		if (is_ia32_Immediate(op)) {
			emit_ia32_Immediate(env, op);
		} else if (is_ia32_ImmConst(node) || is_ia32_ImmSymConst(node)) {
			ia32_emit_immediate(env, node);
		} else {
			ia32_emit_source_register(env, node, pos);
		}
		break;
	case ia32_AddrModeS:
	case ia32_AddrModeD:
		ia32_emit_am(env, node);
		break;
	default:
		assert(0 && "unsupported op type");
	}
}

/**
 * Emits address mode.
 */
void ia32_emit_am(ia32_emit_env_t *env, const ir_node *node) {
	ir_entity *ent       = get_ia32_am_sc(node);
	int        offs      = get_ia32_am_offs_int(node);
	ir_node   *base      = get_irn_n(node, 0);
	int        has_base  = !is_ia32_NoReg_GP(base);
	ir_node   *index     = get_irn_n(node, 1);
	int        has_index = !is_ia32_NoReg_GP(index);

	/* just to be sure... */
	assert(!is_ia32_use_frame(node) || get_ia32_frame_ent(node) != NULL);

	/* emit offset */
	if (ent != NULL) {
		ident *id;

		set_entity_backend_marked(ent, 1);
		id = get_entity_ld_ident(ent);
		if (is_ia32_am_sc_sign(node))
			be_emit_char(env, '-');
		be_emit_ident(env, id);

		if(get_entity_owner(ent) == get_tls_type()) {
			if (get_entity_visibility(ent) == visibility_external_allocated) {
				be_emit_cstring(env, "@INDNTPOFF");
			} else {
				be_emit_cstring(env, "@NTPOFF");
			}
		}
	}

	if(offs != 0) {
		if(ent != NULL) {
			be_emit_irprintf(env->emit, "%+d", offs);
		} else {
			be_emit_irprintf(env->emit, "%d", offs);
		}
	}

	if (has_base || has_index) {
		be_emit_char(env, '(');

		/* emit base */
		if (has_base) {
			ia32_emit_source_register(env, node, 0);
		}

		/* emit index + scale */
		if (has_index) {
			int scale;
			be_emit_char(env, ',');
			ia32_emit_source_register(env, node, 1);

			scale = get_ia32_am_scale(node);
			if (scale > 0) {
				be_emit_irprintf(env->emit, ",%d", 1 << get_ia32_am_scale(node));
			}
		}
		be_emit_char(env, ')');
	}
}

/*************************************************
 *                 _ _                         _
 *                (_) |                       | |
 *   ___ _ __ ___  _| |_    ___ ___  _ __   __| |
 *  / _ \ '_ ` _ \| | __|  / __/ _ \| '_ \ / _` |
 * |  __/ | | | | | | |_  | (_| (_) | | | | (_| |
 *  \___|_| |_| |_|_|\__|  \___\___/|_| |_|\__,_|
 *
 *************************************************/

#undef IA32_DO_EMIT
#define IA32_DO_EMIT(irn) ia32_fprintf_format(F, irn, cmd_buf, cmnt_buf)

/*
 * coding of conditions
 */
struct cmp2conditon_t {
	const char *name;
	pn_Cmp      num;
};

/*
 * positive conditions for signed compares
 */
static
const struct cmp2conditon_t cmp2condition_s[] = {
	{ NULL,              pn_Cmp_False },  /* always false */
	{ "e",               pn_Cmp_Eq },     /* == */
	{ "l",               pn_Cmp_Lt },     /* < */
	{ "le",              pn_Cmp_Le },     /* <= */
	{ "g",               pn_Cmp_Gt },     /* > */
	{ "ge",              pn_Cmp_Ge },     /* >= */
	{ "ne",              pn_Cmp_Lg },     /* != */
	{ NULL,              pn_Cmp_Leg},     /* Floating point: ordered */
};

/*
 * positive conditions for unsigned compares
 */
static
const struct cmp2conditon_t cmp2condition_u[] = {
	{ NULL,              pn_Cmp_False },  /* always false */
	{ "e",               pn_Cmp_Eq },     /* == */
	{ "b",               pn_Cmp_Lt },     /* < */
	{ "be",              pn_Cmp_Le },     /* <= */
	{ "a",               pn_Cmp_Gt },     /* > */
	{ "ae",              pn_Cmp_Ge },     /* >= */
	{ "ne",              pn_Cmp_Lg },     /* != */
	{ NULL,              pn_Cmp_True },   /* always true */
};

/*
 * returns the condition code
 */
static
const char *get_cmp_suffix(pn_Cmp cmp_code)
{
	assert( (cmp2condition_s[cmp_code & 7].num) == (cmp_code & 7));
	assert( (cmp2condition_u[cmp_code & 7].num) == (cmp_code & 7));

	if((cmp_code & ia32_pn_Cmp_Unsigned)) {
		return cmp2condition_u[cmp_code & 7].name;
	} else {
		return cmp2condition_s[cmp_code & 7].name;
	}
}

void ia32_emit_cmp_suffix(ia32_emit_env_t *env, long pnc)
{
	be_emit_string(env, get_cmp_suffix(pnc));
}


/**
 * Returns the target block for a control flow node.
 */
static
ir_node *get_cfop_target_block(const ir_node *irn) {
	return get_irn_link(irn);
}

/**
 * Emits a block label for the given block.
 */
static
void ia32_emit_block_name(ia32_emit_env_t *env, const ir_node *block)
{
	if (has_Block_label(block)) {
		be_emit_string(env, be_gas_label_prefix());
		be_emit_irprintf(env->emit, "%u", (unsigned)get_Block_label(block));
	} else {
		be_emit_cstring(env, BLOCK_PREFIX);
		be_emit_irprintf(env->emit, "%d", get_irn_node_nr(block));
	}
}

/**
 * Emits the target label for a control flow node.
 */
static
void ia32_emit_cfop_target(ia32_emit_env_t * env, const ir_node *node) {
	ir_node *block = get_cfop_target_block(node);

	ia32_emit_block_name(env, block);
}

/** Return the next block in Block schedule */
static ir_node *next_blk_sched(const ir_node *block) {
	return get_irn_link(block);
}

/**
 * Returns the Proj with projection number proj and NOT mode_M
 */
static
ir_node *get_proj(const ir_node *node, long proj) {
	const ir_edge_t *edge;
	ir_node         *src;

	assert(get_irn_mode(node) == mode_T && "expected mode_T node");

	foreach_out_edge(node, edge) {
		src = get_edge_src_irn(edge);

		assert(is_Proj(src) && "Proj expected");
		if (get_irn_mode(src) == mode_M)
			continue;

		if (get_Proj_proj(src) == proj)
			return src;
	}
	return NULL;
}

/**
 * Emits the jump sequence for a conditional jump (cmp + jmp_true + jmp_false)
 */
static
void finish_CondJmp(ia32_emit_env_t *env, const ir_node *node, ir_mode *mode,
                    long pnc) {
	const ir_node *proj_true;
	const ir_node *proj_false;
	const ir_node *block;
	const ir_node *next_block;
	int flipped = 0;

	/* get both Proj's */
	proj_true = get_proj(node, pn_Cond_true);
	assert(proj_true && "CondJmp without true Proj");

	proj_false = get_proj(node, pn_Cond_false);
	assert(proj_false && "CondJmp without false Proj");

	/* for now, the code works for scheduled and non-schedules blocks */
	block = get_nodes_block(node);

	/* we have a block schedule */
	next_block = next_blk_sched(block);

	if (get_cfop_target_block(proj_true) == next_block) {
		/* exchange both proj's so the second one can be omitted */
		const ir_node *t = proj_true;

		proj_true  = proj_false;
		proj_false = t;
		flipped    = 1;
		pnc        = get_negated_pnc(pnc, mode);
	}

	if (mode_is_float(mode)) {
		/* Some floating point comparisons require a test of the parity flag, which
		 * indicates that the result is unordered */
		switch (pnc) {
			case pn_Cmp_Uo:
				be_emit_cstring(env, "\tjp ");
				ia32_emit_cfop_target(env, proj_true);
				be_emit_finish_line_gas(env, proj_true);
				break;

			case pn_Cmp_Leg:
				be_emit_cstring(env, "\tjnp ");
				ia32_emit_cfop_target(env, proj_true);
				be_emit_finish_line_gas(env, proj_true);
				break;

			case pn_Cmp_Eq:
			case pn_Cmp_Lt:
			case pn_Cmp_Le:
				be_emit_cstring(env, "\tjp ");
				ia32_emit_cfop_target(env, proj_false);
				be_emit_finish_line_gas(env, proj_false);
				goto float_jcc;

			case pn_Cmp_Ug:
			case pn_Cmp_Uge:
			case pn_Cmp_Ne:
				be_emit_cstring(env, "\tjp ");
				ia32_emit_cfop_target(env, proj_true);
				be_emit_finish_line_gas(env, proj_true);
				goto float_jcc;

			default:
			float_jcc:
				/* The bits set by floating point compares correspond to unsigned
				 * comparisons */
				pnc |= ia32_pn_Cmp_Unsigned;
				goto emit_jcc;
		}
	} else {
emit_jcc:
		be_emit_cstring(env, "\tj");
		ia32_emit_cmp_suffix(env, pnc);
		be_emit_char(env, ' ');
		ia32_emit_cfop_target(env, proj_true);
		be_emit_finish_line_gas(env, proj_true);
	}

	/* the second Proj might be a fallthrough */
	if (get_cfop_target_block(proj_false) != next_block) {
		be_emit_cstring(env, "\tjmp ");
		ia32_emit_cfop_target(env, proj_false);
		be_emit_finish_line_gas(env, proj_false);
	} else {
		be_emit_cstring(env, "\t/* fallthrough to ");
		ia32_emit_cfop_target(env, proj_false);
		be_emit_cstring(env, " */");
		be_emit_finish_line_gas(env, proj_false);
	}
}

/**
 * Emits code for conditional jump.
 */
static
void CondJmp_emitter(ia32_emit_env_t *env, const ir_node *node) {
	be_emit_cstring(env, "\tcmp");
	ia32_emit_mode_suffix(env, node);
	be_emit_char(env, ' ');
	ia32_emit_binop(env, node);
	be_emit_finish_line_gas(env, node);

	finish_CondJmp(env, node, mode_Iu, get_ia32_pncode(node));
}

/**
 * Emits code for conditional jump with two variables.
 */
static
void emit_ia32_CondJmp(ia32_emit_env_t *env, const ir_node *node) {
	CondJmp_emitter(env, node);
}

/**
 * Emits code for conditional test and jump.
 */
static
void TestJmp_emitter(ia32_emit_env_t *env, const ir_node *node) {
	be_emit_cstring(env, "\ttest");
	ia32_emit_mode_suffix(env, node);
	be_emit_char(env, ' ');

	ia32_emit_binop(env, node);
	be_emit_finish_line_gas(env, node);

	finish_CondJmp(env, node, mode_Iu, get_ia32_pncode(node));
}

/**
 * Emits code for conditional test and jump with two variables.
 */
static
void emit_ia32_TestJmp(ia32_emit_env_t *env, const ir_node *node) {
	TestJmp_emitter(env, node);
}

/**
 * Emits code for conditional SSE floating point jump with two variables.
 */
static
void emit_ia32_xCondJmp(ia32_emit_env_t *env, const ir_node *node) {
	be_emit_cstring(env, "\tucomi");
	ia32_emit_xmm_mode_suffix(env, node);
	be_emit_char(env, ' ');
	ia32_emit_binop(env, node);
	be_emit_finish_line_gas(env, node);

	finish_CondJmp(env, node, mode_F, get_ia32_pncode(node));
}

/**
 * Emits code for conditional x87 floating point jump with two variables.
 */
static
void emit_ia32_x87CondJmp(ia32_emit_env_t *env, const ir_node *node) {
	const ia32_x87_attr_t *x87_attr = get_ia32_x87_attr_const(node);
	const char            *reg      = x87_attr->x87[1]->name;
	long                   pnc      = get_ia32_pncode(node);

	switch (get_ia32_irn_opcode(node)) {
	case iro_ia32_fcomrJmp:
		pnc = get_inversed_pnc(pnc);
		reg = x87_attr->x87[0]->name;
	case iro_ia32_fcomJmp:
	default:
		be_emit_cstring(env, "\tfucom ");
		break;
	case iro_ia32_fcomrpJmp:
		pnc = get_inversed_pnc(pnc);
		reg = x87_attr->x87[0]->name;
	case iro_ia32_fcompJmp:
		be_emit_cstring(env, "\tfucomp ");
		break;
	case iro_ia32_fcomrppJmp:
		pnc = get_inversed_pnc(pnc);
	case iro_ia32_fcomppJmp:
		be_emit_cstring(env, "\tfucompp ");
		reg = "";
		break;
	}

	if(reg[0] != '\0') {
		be_emit_char(env, '%');
		be_emit_string(env, reg);
	}
	be_emit_finish_line_gas(env, node);

	be_emit_cstring(env, "\tfnstsw %ax");
	be_emit_finish_line_gas(env, node);
	be_emit_cstring(env, "\tsahf");
	be_emit_finish_line_gas(env, node);

	finish_CondJmp(env, node, mode_E, pnc);
}

static
void CMov_emitter(ia32_emit_env_t *env, const ir_node *node)
{
	const arch_register_t *in1, *in2, *out;
	long  pnc = get_ia32_pncode(node);

	out = arch_get_irn_register(env->arch_env, node);

	/* we have to emit the cmp first, because the destination register */
	/* could be one of the compare registers                           */
	if (is_ia32_xCmpCMov(node)) {