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 iropt --- optimizations of an ir node.
23 * @author Martin Trapp, Christian Schaefer, Goetz Lindenmaier, Michael Beck
26 #ifndef FIRM_IR_IROPT_H
27 #define FIRM_IR_IROPT_H
29 #include "firm_types.h"
33 * The Floating point model.
35 * Several basic properties are defined:
36 * - fp_explicit_rounding
37 * - fp_strict_algebraic
39 * - fp_strict_eval_order
41 * - fp_environment_access
43 * From those basic properties three general models are defined,
44 * compatible to the VC8 compiler:
46 * Default mode. Associative and distributive law forbidden unless a transformation
47 * is guaranteed to produce the same result.
48 * No FPU environment access. No FP exception semantics.
50 * Slowest mode. Additionally to fp_model_precise allows correct handling of
51 * FP exceptions and FPU environment access.
53 * Fastest mode. Associative and distributive law allowed at the expense
54 * of floating point accuracy and correctness. Explicit rounding is disabled.
56 typedef enum fp_model_t {
57 fp_explicit_rounding = (1u << 0), /**< Explicit rounding at assignments, typecasts, return
58 and function calls. Conv nodes may NOT be removed, even
59 if they look useless. */
60 fp_strict_algebraic = (1u << 1), /**< Strict adherence to non-associative and non-distributive
61 algebra unless the same result is guaranteed. */
62 fp_contradictions = (1u << 2), /**< FP contradictions are enabled. Only for backend. */
63 fp_strict_eval_order = (1u << 3), /**< FP instructions must be strict evaluated in given order. */
64 fp_exceptions = (1u << 4), /**< FP exceptions are supported. No reordering that changes
65 the exception flow are allowed. Backends must generate
66 synchronized exception code. */
67 fp_environment_access = (1u << 5), /**< FPU environment can be accessed. Even Constant folding
70 /** Precise floating point model. Default. */
71 fp_model_precise = fp_explicit_rounding|fp_strict_algebraic|fp_contradictions,
72 /** Strict floating point model. */
73 fp_model_strict = fp_explicit_rounding|fp_strict_algebraic|fp_strict_eval_order|
74 fp_exceptions|fp_environment_access,
75 /** Fast floating point model. */
76 fp_model_fast = fp_contradictions
79 /** If the expression referenced can be evaluated statically
80 * computed_value returns a tarval representing the result.
81 * Else returns tarval_bad. */
82 FIRM_API ir_tarval *computed_value(const ir_node *n);
84 /** Applies all optimizations to n that are expressible as a pattern
85 * in Firm, i.e., they need not a walk of the graph.
86 * Returns a better node for n. Does not free n -- other nodes could
89 * An equivalent optimization is applied in the constructors defined in
90 * ircons.ch. There n is freed if a better node could be found.
92 FIRM_API ir_node *optimize_in_place(ir_node *n);
95 * checks whether 1 value is the negated other value
97 FIRM_API int ir_is_negated_value(const ir_node *a, const ir_node *b);
100 * (conservatively) approximates all possible relations when comparing
101 * the value @p left and @p right
103 FIRM_API ir_relation ir_get_possible_cmp_relations(const ir_node *left,
104 const ir_node *right);
107 * tests whether a given Cmp node is an equal/not-equal test with 0
108 * (this is a bit tricky because it has to catch x!=0 for the signed case and
109 * x>0 for the unsigned case)
111 FIRM_API int ir_is_equality_cmp_0(const ir_node *node);