2 * Copyright (C) 1995-2007 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 Optimizations regarding Confirm nodes.
23 * @author Michael Beck
26 * Optimizations regarding Confirm nodes.
27 * These optimizations are not means to be run from
28 * frontends, they are called from iropt.
30 #ifndef FIRM_OPT_CONFIRMS_H
31 #define FIRM_OPT_CONFIRMS_H
33 #include "firm_types.h"
36 * Check, if the value of a node is != 0.
38 * This is a often needed case, so we handle here Confirm
41 * @param blk the block for which the check is done
42 * @param n a node representing the value
43 * @param confirm if n is confirmed to be != 0, returns
44 * the the Confirm-node, else NULL
46 int value_not_zero(ir_node *blk, ir_node *n, ir_node **confirm);
49 * Check, if the value of a node cannot represent a NULL pointer.
51 * - If option sel_based_null_check_elim is enabled, all
52 * Sel nodes can be skipped.
53 * - A SymConst(entity) is NEVER a NULL pointer
54 * - A Const != NULL is NEVER a NULL pointer
55 * - Confirms are evaluated
57 * @param blk the block for which the check is done
58 * @param n a node representing the value
59 * @param confirm if n is confirmed to be != NULL, returns
60 * the the Confirm-node, else NULL
62 int value_not_null(ir_node *blk, ir_node *n, ir_node **confirm);
65 * Possible return values of value_classify().
67 typedef enum _value_classify_sign {
68 value_classified_unknown = 0, /**< could not classify */
69 value_classified_positive = 1, /**< value is positive, i.e. >= 0 */
70 value_classified_negative = -1 /**< value is negative, i.e. <= 0 if
71 no signed zero exists or < 0 else */
72 } value_classify_sign;
75 * Check, if the value of a node can be confirmed >= 0 or <= 0,
76 * If the mode of the value did not honor signed zeros, else
77 * check for >= 0 or < 0.
79 * @param n a node representing the value
81 value_classify_sign classify_value_sign(ir_node *n);
84 * Return the value of a Cmp if one or both predecessors
87 * @param cmp the compare node that will be evaluated
88 * @param left the left operand of the Cmp
89 * @param right the right operand of the Cmp
90 * @param pnc the compare relation
92 tarval *computed_value_Cmp_Confirm(ir_node *cmp, ir_node *left, ir_node *right, pn_Cmp pnc);
94 #endif /* FIRM_OPT_CONFIRMS_H */