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
26 #ifndef FIRM_IR_IRARCH_H
27 #define FIRM_IR_IRARCH_H
29 #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 mode the mode of the instruction
50 * @param tv for MUL instruction, the multiplication constant
52 * @return the costs of this instruction
54 typedef int (*evaluate_costs_func)(insn_kind kind, const ir_mode *mode, ir_tarval *tv);
57 * A parameter structure that drives the machine dependent Firm
60 typedef struct ir_settings_arch_dep_t {
61 /* Mul optimization */
62 unsigned also_use_subs : 1; /**< Use also Subs when resolving Muls to shifts */
63 unsigned maximum_shifts; /**< The maximum number of shifts that shall be inserted for a mul. */
64 unsigned highest_shift_amount; /**< The highest shift amount you want to
65 tolerate. Muls which would require a higher
66 shift constant are left. */
67 evaluate_costs_func evaluate; /**< Evaluate the costs of a generated instruction. */
69 /* Div/Mod optimization */
70 unsigned allow_mulhs : 1; /**< Use the Mulhs operation for division by constant */
71 unsigned allow_mulhu : 1; /**< Use the Mulhu operation for division by constant */
72 unsigned max_bits_for_mulh; /**< Maximum number of bits the Mulh operation can take.
73 Modes with higher amount of bits will use Mulh */
74 } ir_settings_arch_dep_t;
77 * A factory function, that provides architecture parameters for
78 * machine dependent optimizations.
80 typedef const ir_settings_arch_dep_t *(*arch_dep_params_factory_t)(void);
87 arch_dep_mul_to_shift = 1, /**< optimize Mul into Shift/Add/Sub */
88 arch_dep_div_by_const = 2, /**< optimize Div into Shift/Add/Mulh */
89 arch_dep_mod_by_const = 4 /**< optimize Mod into Shift/Add/Mulh */
91 ENUM_BITSET(arch_dep_opts_t)
94 * Set the optimizations that shall be applied.
95 * @param opts An optimization bit mask.
97 FIRM_API void arch_dep_set_opts(arch_dep_opts_t opts);
100 * Replace Muls with Lea/Shifts/Add/Subs if these
101 * have smaller costs than the original multiplication.
103 * @param irn The Firm node to inspect.
104 * @return A replacement expression for irn.
106 FIRM_API ir_node *arch_dep_replace_mul_with_shifts(ir_node *irn);
109 * Replace Divs with Shifts and Add/Subs and Mulh.
110 * This function is driven by the 3 parameters:
113 * - max_bits_for_mulh
115 * If irn is a Div with a Const, the constant is inspected if it meets the
116 * requirements of the variables stated above. If a Shl/Add/Sub/Mulh
117 * sequence can be generated that meets these requirements, this expression
118 * is returned. In each other case irn is returned unmodified.
120 * @param irn The Firm node to inspect.
121 * @return A replacement expression for irn.
123 FIRM_API ir_node *arch_dep_replace_div_by_const(ir_node *irn);
126 * Replace Mods with Shifts and Add/Subs and Mulh.
127 * This function is driven by the 3 parameters:
130 * - max_bits_for_mulh
132 * If irn is a Mod with a Const, the constant is inspected if it meets the
133 * requirements of the variables stated above. If a Shl/Add/Sub/Mulh
134 * sequence can be generated that meets these requirements, this expression
135 * is returned. In each other case irn is returned unmodified.
137 * @param irn The Firm node to inspect.
138 * @return A replacement expression for irn.
140 FIRM_API ir_node *arch_dep_replace_mod_by_const(ir_node *irn);