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 * @addtogroup iroptimize
38 * The Multiplication replacement can consist of the following instructions.
40 typedef enum insn_kind {
41 LEA, /**< the LEA instruction */
42 SHIFT, /**< the SHIFT instruction */
43 SUB, /**< the SUB instruction */
44 ADD, /**< the ADD instruction */
45 ZERO, /**< creates a ZERO constant */
46 MUL, /**< the original MUL instruction */
47 ROOT /**< the ROOT value that is multiplied */
51 * A Callback for evaluating the costs of an instruction.
53 * @param kind the instruction
54 * @param mode the mode of the instruction
55 * @param tv for MUL instruction, the multiplication constant
57 * @return the costs of this instruction
59 typedef int (*evaluate_costs_func)(insn_kind kind, const ir_mode *mode, ir_tarval *tv);
62 * A parameter structure that drives the machine dependent Firm
65 typedef struct ir_settings_arch_dep_t {
66 /* Mul optimization */
67 unsigned also_use_subs : 1; /**< Use also Subs when resolving Muls to shifts */
68 unsigned maximum_shifts; /**< The maximum number of shifts that shall be inserted for a mul. */
69 unsigned highest_shift_amount; /**< The highest shift amount you want to
70 tolerate. Muls which would require a higher
71 shift constant are left. */
72 evaluate_costs_func evaluate; /**< Evaluate the costs of a generated instruction. */
74 /* Div/Mod optimization */
75 unsigned allow_mulhs : 1; /**< Use the Mulhs operation for division by constant */
76 unsigned allow_mulhu : 1; /**< Use the Mulhu operation for division by constant */
77 unsigned max_bits_for_mulh; /**< Maximum number of bits the Mulh operation can take.
78 Modes with higher amount of bits will use Mulh */
79 } ir_settings_arch_dep_t;
82 * A factory function, that provides architecture parameters for
83 * machine dependent optimizations.
85 typedef const ir_settings_arch_dep_t *(*arch_dep_params_factory_t)(void);
90 typedef enum arch_dep_opts_t {
92 arch_dep_mul_to_shift = 1u << 0, /**< optimize Mul into Shift/Add/Sub */
93 arch_dep_div_by_const = 1u << 1, /**< optimize Div into Shift/Add/Mulh */
94 arch_dep_mod_by_const = 1u << 2 /**< optimize Mod into Shift/Add/Mulh */
96 ENUM_BITSET(arch_dep_opts_t)
99 * Sets the optimizations that shall be applied.
100 * @param opts An optimization bit mask.
102 FIRM_API void arch_dep_set_opts(arch_dep_opts_t opts);
105 * Replaces Muls with Lea/Shifts/Add/Subs if these
106 * have smaller costs than the original multiplication.
108 * @param irn The Firm node to inspect.
109 * @return A replacement expression for irn.
111 FIRM_API ir_node *arch_dep_replace_mul_with_shifts(ir_node *irn);
114 * Replaces Divs with Shifts and Add/Subs and Mulh.
115 * This function is driven by the 3 parameters:
118 * - max_bits_for_mulh
120 * If irn is a Div with a Const, the constant is inspected if it meets the
121 * requirements of the variables stated above. If a Shl/Add/Sub/Mulh
122 * sequence can be generated that meets these requirements, this expression
123 * is returned. In each other case irn is returned unmodified.
125 * @param irn The Firm node to inspect.
126 * @return A replacement expression for irn.
128 FIRM_API ir_node *arch_dep_replace_div_by_const(ir_node *irn);
131 * Replaces Mods with Shifts and Add/Subs and Mulh.
132 * This function is driven by the 3 parameters:
135 * - max_bits_for_mulh
137 * If irn is a Mod with a Const, the constant is inspected if it meets the
138 * requirements of the variables stated above. If a Shl/Add/Sub/Mulh
139 * sequence can be generated that meets these requirements, this expression
140 * is returned. In each other case irn is returned unmodified.
142 * @param irn The Firm node to inspect.
143 * @return A replacement expression for irn.
145 FIRM_API ir_node *arch_dep_replace_mod_by_const(ir_node *irn);