2 * Copyright (C) 1995-2008 University of Karlsruhe. All right reserved.
4 * This file is part of libFirm.
6 * This file may be distributed and/or modified under the terms of the
7 * GNU General Public License version 2 as published by the Free Software
8 * Foundation and appearing in the file LICENSE.GPL included in the
9 * packaging of this file.
11 * Licensees holding valid libFirm Professional Edition licenses may use
12 * this file in accordance with the libFirm Commercial License.
13 * Agreement provided with the Software.
15 * This file is provided AS IS with NO WARRANTY OF ANY KIND, INCLUDING THE
16 * WARRANTY OF DESIGN, MERCHANTABILITY AND FITNESS FOR A PARTICULAR
22 * @brief Some machine dependent optimizations.
24 * @author Sebastian Hack
27 #ifndef FIRM_IR_IRARCH_H
28 #define FIRM_IR_IRARCH_H
30 #include "firm_types.h"
33 * The Multiplication replacement can consist of the following instructions.
36 LEA, /**< the LEA instruction */
37 SHIFT, /**< the SHIFT instruction */
38 SUB, /**< the SUB instruction */
39 ADD, /**< the ADD instruction */
40 ZERO, /**< creates a ZERO constant */
41 MUL, /**< the original MUL instruction */
42 ROOT /**< the ROOT value that is multiplied */
46 * A Callback for evaluating the costs of an instruction.
48 * @param kind the instruction
49 * @param tv for MUL instruction, the multiplication constant
51 * @return the costs of this instruction
53 typedef int (*evaluate_costs_func)(insn_kind kind, tarval *tv);
56 * A parameter structure that drives the machine dependent Firm
59 struct ir_settings_arch_dep_t {
60 /* Mul optimization */
61 unsigned also_use_subs : 1; /**< Use also Subs when resolving Muls to shifts */
62 unsigned maximum_shifts; /**< The maximum number of shifts that shall be inserted for a mul. */
63 unsigned highest_shift_amount; /**< The highest shift amount you want to
64 tolerate. Muls which would require a higher
65 shift constant are left. */
66 evaluate_costs_func evaluate; /**< Evaluate the costs of a generated instruction. */
68 /* Div/Mod optimization */
69 unsigned allow_mulhs : 1; /**< Use the Mulhs operation for division by constant */
70 unsigned allow_mulhu : 1; /**< Use the Mulhu operation for division by constant */
71 unsigned max_bits_for_mulh; /**< Maximum number of bits the Mulh operation can take.
72 Modes with higher amount of bits will use Mulh */
76 * A factory function, that provides architecture parameters for
77 * machine dependent optimizations.
79 typedef const ir_settings_arch_dep_t *(*arch_dep_params_factory_t)(void);
82 * A default parameter factory for testing purposes.
84 const ir_settings_arch_dep_t *arch_dep_default_factory(void);
91 arch_dep_mul_to_shift = 1, /**< optimize Mul into Shift/Add/Sub */
92 arch_dep_div_by_const = 2, /**< optimize Div into Shift/Add/Mulh */
93 arch_dep_mod_by_const = 4 /**< optimize Mod into Shift/Add/Mulh */
97 * Initialize the machine dependent optimizations.
98 * @param factory A factory that delivers parameters for these
99 * optimizations. If NULL is passed, or this method
100 * is not called, the machine dependent optimizations
101 * are not enabled at all.
103 void arch_dep_init(arch_dep_params_factory_t factory);
106 * Set the optimizations that shall be applied.
107 * @param opts An optimization bit mask.
109 void arch_dep_set_opts(arch_dep_opts_t opts);
112 * Replace Muls with Shifts and Add/Subs.
113 * This function is driven by the 3 parameters:
116 * - highest_shift_amount
118 * If irn is a Mul with a Const, the constant is inspected if it meets the
119 * requirements of the three variables stated above. If a Shl/Add/Sub
120 * sequence can be generated that meets these requirements, this expression
121 * is returned. In each other case irn is returned unmodified.
123 * @param irn The Firm node to inspect.
124 * @return A replacement expression for irn.
126 ir_node *arch_dep_replace_mul_with_shifts(ir_node *irn);
129 * Replace Divs with Shifts and Add/Subs and Mulh.
130 * This function is driven by the 3 parameters:
133 * - max_bits_for_mulh
135 * If irn is a Div with a Const, the constant is inspected if it meets the
136 * requirements of the variables stated above. If a Shl/Add/Sub/Mulh
137 * sequence can be generated that meets these requirements, this expression
138 * is returned. In each other case irn is returned unmodified.
140 * @param irn The Firm node to inspect.
141 * @return A replacement expression for irn.
143 ir_node *arch_dep_replace_div_by_const(ir_node *irn);
146 * Replace Mods with Shifts and Add/Subs and Mulh.
147 * This function is driven by the 3 parameters:
150 * - max_bits_for_mulh
152 * If irn is a Mod with a Const, the constant is inspected if it meets the
153 * requirements of the variables stated above. If a Shl/Add/Sub/Mulh
154 * sequence can be generated that meets these requirements, this expression
155 * is returned. In each other case irn is returned unmodified.
157 * @param irn The Firm node to inspect.
158 * @return A replacement expression for irn.
160 ir_node *arch_dep_replace_mod_by_const(ir_node *irn);
163 * Replace DivMods with Shifts and Add/Subs and Mulh.
164 * This function is driven by the 3 parameters:
167 * - max_bits_for_mulh
169 * If irn is a DivMod with a Const, the constant is inspected if it meets the
170 * requirements of the variables stated above. If a Shl/Add/Sub/Mulh
171 * sequence can be generated that meets these requirements, this expression
172 * is returned. In each other case irn is returned unmodified.
174 * @param div After call contains the Firm node div result or NULL.
175 * @param mod After call contains the Firm node mod result or NULL.
176 * @param irn The Firm node to inspect.
178 void arch_dep_replace_divmod_by_const(ir_node **div, ir_node **mod, ir_node *irn);