/*
* Copyright (C) 1995-2008 University of Karlsruhe. All right reserved.
*
* This file is part of libFirm.
*
* This file may be distributed and/or modified under the terms of the
* GNU General Public License version 2 as published by the Free Software
* Foundation and appearing in the file LICENSE.GPL included in the
* packaging of this file.
*
* Licensees holding valid libFirm Professional Edition licenses may use
* this file in accordance with the libFirm Commercial License.
* Agreement provided with the Software.
*
* This file is provided AS IS with NO WARRANTY OF ANY KIND, INCLUDING THE
* WARRANTY OF DESIGN, MERCHANTABILITY AND FITNESS FOR A PARTICULAR
* PURPOSE.
*/
/**
* @file
* @brief Some machine dependent optimizations.
* @date 1.10.2004
* @author Sebastian Hack
* @version $Id$
*/
#ifndef FIRM_IR_IRARCH_H
#define FIRM_IR_IRARCH_H
#include "firm_types.h"
#include "begin.h"
/**
* The Multiplication replacement can consist of the following instructions.
*/
typedef enum instr {
LEA, /**< the LEA instruction */
SHIFT, /**< the SHIFT instruction */
SUB, /**< the SUB instruction */
ADD, /**< the ADD instruction */
ZERO, /**< creates a ZERO constant */
MUL, /**< the original MUL instruction */
ROOT /**< the ROOT value that is multiplied */
} insn_kind;
/**
* A Callback for evaluating the costs of an instruction.
*
* @param kind the instruction
* @param tv for MUL instruction, the multiplication constant
*
* @return the costs of this instruction
*/
typedef int (*evaluate_costs_func)(insn_kind kind, ir_tarval *tv);
/**
* A parameter structure that drives the machine dependent Firm
* optimizations.
*/
struct ir_settings_arch_dep_t {
/* Mul optimization */
unsigned also_use_subs : 1; /**< Use also Subs when resolving Muls to shifts */
unsigned maximum_shifts; /**< The maximum number of shifts that shall be inserted for a mul. */
unsigned highest_shift_amount; /**< The highest shift amount you want to
tolerate. Muls which would require a higher
shift constant are left. */
evaluate_costs_func evaluate; /**< Evaluate the costs of a generated instruction. */
/* Div/Mod optimization */
unsigned allow_mulhs : 1; /**< Use the Mulhs operation for division by constant */
unsigned allow_mulhu : 1; /**< Use the Mulhu operation for division by constant */
unsigned max_bits_for_mulh; /**< Maximum number of bits the Mulh operation can take.
Modes with higher amount of bits will use Mulh */
};
/**
* A factory function, that provides architecture parameters for
* machine dependent optimizations.
*/
typedef const ir_settings_arch_dep_t *(*arch_dep_params_factory_t)(void);
/**
* Optimization flags.
*/
typedef enum {
arch_dep_none = 0,
arch_dep_mul_to_shift = 1, /**< optimize Mul into Shift/Add/Sub */
arch_dep_div_by_const = 2, /**< optimize Div into Shift/Add/Mulh */
arch_dep_mod_by_const = 4 /**< optimize Mod into Shift/Add/Mulh */
} arch_dep_opts_t;
/**
* Set the optimizations that shall be applied.
* @param opts An optimization bit mask.
*/
FIRM_API void arch_dep_set_opts(arch_dep_opts_t opts);
/**
* Replace Muls with Lea/Shifts/Add/Subs if these
* have smaller costs than the original multiplication.
*
* @param irn The Firm node to inspect.
* @return A replacement expression for irn.
*/
FIRM_API ir_node *arch_dep_replace_mul_with_shifts(ir_node *irn);
/**
* Replace Divs with Shifts and Add/Subs and Mulh.
* This function is driven by the 3 parameters:
* - allow_mulhu
* - allow_mulhs
* - max_bits_for_mulh
*
* If irn is a Div with a Const, the constant is inspected if it meets the
* requirements of the variables stated above. If a Shl/Add/Sub/Mulh
* sequence can be generated that meets these requirements, this expression
* is returned. In each other case irn is returned unmodified.
*
* @param irn The Firm node to inspect.
* @return A replacement expression for irn.
*/
FIRM_API ir_node *arch_dep_replace_div_by_const(ir_node *irn);
/**
* Replace Mods with Shifts and Add/Subs and Mulh.
* This function is driven by the 3 parameters:
* - allow_mulhu
* - allow_mulhs
* - max_bits_for_mulh
*
* If irn is a Mod with a Const, the constant is inspected if it meets the
* requirements of the variables stated above. If a Shl/Add/Sub/Mulh
* sequence can be generated that meets these requirements, this expression
* is returned. In each other case irn is returned unmodified.
*
* @param irn The Firm node to inspect.
* @return A replacement expression for irn.
*/
FIRM_API ir_node *arch_dep_replace_mod_by_const(ir_node *irn);
/**
* Replace DivMods with Shifts and Add/Subs and Mulh.
* This function is driven by the 3 parameters:
* - allow_mulhu
* - allow_mulhs
* - max_bits_for_mulh
*
* If irn is a DivMod with a Const, the constant is inspected if it meets the
* requirements of the variables stated above. If a Shl/Add/Sub/Mulh
* sequence can be generated that meets these requirements, this expression
* is returned. In each other case irn is returned unmodified.
*
* @param div After call contains the Firm node div result or NULL.
* @param mod After call contains the Firm node mod result or NULL.
* @param irn The Firm node to inspect.
*/
FIRM_API void arch_dep_replace_divmod_by_const(ir_node **div, ir_node **mod,
ir_node *irn);
#include "end.h"
#endif