4 * @author Sebastian Hack
5 * @brief Some machine dependent optimizations.
10 #ifndef __FIRM_IRARCH_H
11 #define __FIRM_IRARCH_H
16 * A parameter structure that drives the machine dependent Firm
20 /* Mul optimization */
21 int also_use_subs : 1; /**< Use also Subs when resolving muls to shifts */
22 int maximum_shifts; /**< The maximum number of shifts that shall be inserted for a mul. */
23 unsigned highest_shift_amount; /**< The highest shift amount you want to
24 tolerate. Muls which would require a higher
25 shift constant are left. */
27 /* Div/Mod optimization */
28 int allow_mulhs : 1; /**< Use the Mulhs operation for division by constant */
29 int allow_mulhu : 1; /**< Use the Mulhu operation for division by constant */
30 unsigned max_bits_for_mulh; /**< Maximum number of bits the Mulh operation can take.
31 Modes with higher amount of bits will use Mulh */
35 * A factory function, that provides architecture parameters for
36 * machine dependent optimizations.
38 typedef const arch_dep_params_t *(*arch_dep_params_factory_t)(void);
41 * A default parameter factory for testing purposes.
43 const arch_dep_params_t *arch_dep_default_factory(void);
50 arch_dep_mul_to_shift = 1, /**< optimize Mul into Shift/Add/Sub */
51 arch_dep_div_by_const = 2, /**< optimize Div into Shift/Add/Mulh */
52 arch_dep_mod_by_const = 4 /**< optimize Mod into Shift/Add/Mulh */
56 * Initialize the machine dependent optimizations.
57 * @param factory A factory that delivers parameters for these
58 * optimizations. If NULL is passed, or this method
59 * is not called, the machine dependent optimizations
60 * are not enabled at all.
62 void arch_dep_init(arch_dep_params_factory_t factory);
65 * Set the optimizations that shall be applied.
66 * @param opts An optimization bit mask.
68 void arch_dep_set_opts(arch_dep_opts_t opts);
71 * Replace Muls with Shifts and Add/Subs.
72 * This function is driven by the 3 parameters:
75 * - highest_shift_amount
77 * If irn is a Mul with a Const, The constant is inspected, if it meets the
78 * requirements of the three variables stated above. If a Shl/Add/Sub
79 * sequence can be generated, that meets these requirements, this expression
80 * is returned. In each other case, irn is returned unmodified.
82 * @param irn The Firm node to inspect.
83 * @return A replacement expression for irn.
85 ir_node *arch_dep_replace_mul_with_shifts(ir_node *irn);
88 * Replace Divs with Shifts and Add/Subs and Mulh.
89 * This function is driven by the 3 parameters:
93 * If irn is a Div with a Const, The constant is inspected, if it meets the
94 * requirements of the variables stated above. If a Shl/Add/Sub/Mulh
95 * sequence can be generated, that meets these requirements, this expression
96 * is returned. In each other case, irn is returned unmodified.
98 * @param irn The Firm node to inspect.
99 * @return A replacement expression for irn.
101 ir_node *arch_dep_replace_div_by_const(ir_node *irn);
104 * Replace Mods with Shifts and Add/Subs and Mulh.
105 * This function is driven by the 3 parameters:
109 * If irn is a Mod with a Const, The constant is inspected, if it meets the
110 * requirements of the variables stated above. If a Shl/Add/Sub/Mulh
111 * sequence can be generated, that meets these requirements, this expression
112 * is returned. In each other case, irn is returned unmodified.
114 * @param irn The Firm node to inspect.
115 * @return A replacement expression for irn.
117 ir_node *arch_dep_replace_mod_by_const(ir_node *irn);
120 * Replace DivMods with Shifts and Add/Subs and Mulh.
121 * This function is driven by the 3 parameters:
125 * If irn is a DivMod with a Const, The constant is inspected, if it meets the
126 * requirements of the variables stated above. If a Shl/Add/Sub/Mulh
127 * sequence can be generated, that meets these requirements, this expression
128 * is returned. In each other case, irn is returned unmodified.
130 * @param div After call contains the Firm node div result or NULL.
131 * @param mod After call contains the Firm node mod result or NULL.
132 * @param irn The Firm node to inspect.
134 void arch_dep_replace_divmod_by_const(ir_node **div, ir_node **mod, ir_node *irn);