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"
34 * The Multiplication replacement can consist of the following instructions.
37 LEA, /**< the LEA instruction */
38 SHIFT, /**< the SHIFT instruction */
39 SUB, /**< the SUB instruction */
40 ADD, /**< the ADD instruction */
41 ZERO, /**< creates a ZERO constant */
42 MUL, /**< the original MUL instruction */
43 ROOT /**< the ROOT value that is multiplied */
47 * A Callback for evaluating the costs of an instruction.
49 * @param kind the instruction
50 * @param mode the mode of the instruction
51 * @param tv for MUL instruction, the multiplication constant
53 * @return the costs of this instruction
55 typedef int (*evaluate_costs_func)(insn_kind kind, const ir_mode *mode, ir_tarval *tv);
58 * A parameter structure that drives the machine dependent Firm
61 struct ir_settings_arch_dep_t {
62 /* Mul optimization */
63 unsigned also_use_subs : 1; /**< Use also Subs when resolving Muls to shifts */
64 unsigned maximum_shifts; /**< The maximum number of shifts that shall be inserted for a mul. */
65 unsigned highest_shift_amount; /**< The highest shift amount you want to
66 tolerate. Muls which would require a higher
67 shift constant are left. */
68 evaluate_costs_func evaluate; /**< Evaluate the costs of a generated instruction. */
70 /* Div/Mod optimization */
71 unsigned allow_mulhs : 1; /**< Use the Mulhs operation for division by constant */
72 unsigned allow_mulhu : 1; /**< Use the Mulhu operation for division by constant */
73 unsigned max_bits_for_mulh; /**< Maximum number of bits the Mulh operation can take.
74 Modes with higher amount of bits will use Mulh */
78 * A factory function, that provides architecture parameters for
79 * machine dependent optimizations.
81 typedef const ir_settings_arch_dep_t *(*arch_dep_params_factory_t)(void);
88 arch_dep_mul_to_shift = 1, /**< optimize Mul into Shift/Add/Sub */
89 arch_dep_div_by_const = 2, /**< optimize Div into Shift/Add/Mulh */
90 arch_dep_mod_by_const = 4 /**< optimize Mod into Shift/Add/Mulh */
92 ENUM_BITSET(arch_dep_opts_t)
95 * Set the optimizations that shall be applied.
96 * @param opts An optimization bit mask.
98 FIRM_API void arch_dep_set_opts(arch_dep_opts_t opts);
101 * Replace Muls with Lea/Shifts/Add/Subs if these
102 * have smaller costs than the original multiplication.
104 * @param irn The Firm node to inspect.
105 * @return A replacement expression for irn.
107 FIRM_API ir_node *arch_dep_replace_mul_with_shifts(ir_node *irn);
110 * Replace Divs with Shifts and Add/Subs and Mulh.
111 * This function is driven by the 3 parameters:
114 * - max_bits_for_mulh
116 * If irn is a Div with a Const, the constant is inspected if it meets the
117 * requirements of the variables stated above. If a Shl/Add/Sub/Mulh
118 * sequence can be generated that meets these requirements, this expression
119 * is returned. In each other case irn is returned unmodified.
121 * @param irn The Firm node to inspect.
122 * @return A replacement expression for irn.
124 FIRM_API ir_node *arch_dep_replace_div_by_const(ir_node *irn);
127 * Replace Mods with Shifts and Add/Subs and Mulh.
128 * This function is driven by the 3 parameters:
131 * - max_bits_for_mulh
133 * If irn is a Mod with a Const, the constant is inspected if it meets the
134 * requirements of the variables stated above. If a Shl/Add/Sub/Mulh
135 * sequence can be generated that meets these requirements, this expression
136 * is returned. In each other case irn is returned unmodified.
138 * @param irn The Firm node to inspect.
139 * @return A replacement expression for irn.
141 FIRM_API ir_node *arch_dep_replace_mod_by_const(ir_node *irn);
144 * Replace DivMods with Shifts and Add/Subs and Mulh.
145 * This function is driven by the 3 parameters:
148 * - max_bits_for_mulh
150 * If irn is a DivMod with a Const, the constant is inspected if it meets the
151 * requirements of the variables stated above. If a Shl/Add/Sub/Mulh
152 * sequence can be generated that meets these requirements, this expression
153 * is returned. In each other case irn is returned unmodified.
155 * @param div After call contains the Firm node div result or NULL.
156 * @param mod After call contains the Firm node mod result or NULL.
157 * @param irn The Firm node to inspect.
159 FIRM_API void arch_dep_replace_divmod_by_const(ir_node **div, ir_node **mod,