1 /**************************************************************************
2 *
3 * Copyright 2013
4 * All Rights Reserved.
5 *
6 * Permission is hereby granted, free of charge, to any person obtaining a
7 * copy of this software and associated documentation files (the
8 * "Software"), to deal in the Software without restriction, including
9 * without limitation the rights to use, copy, modify, merge, publish,
10 * distribute, sub license, and/or sell copies of the Software, and to
11 * permit persons to whom the Software is furnished to do so, subject to
12 * the following conditions:
13 *
14 * The above copyright notice and this permission notice (including the
15 * next paragraph) shall be included in all copies or substantial portions
16 * of the Software.
17 *
18 * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS
19 * OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF
20 * MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND NON-INFRINGEMENT.
21 * IN NO EVENT SHALL VMWARE AND/OR ITS SUPPLIERS BE LIABLE FOR
22 * ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION OF CONTRACT,
23 * TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION WITH THE
24 * SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.
25 *
26 **************************************************************************/
27
28
29 /**
30 * @file
31 * Helper
32 *
33 * The functions in this file implement arthmetic operations with support
34 * for overflow detection and reporting.
35 *
36 */
37
38 #include "lp_bld_arit_overflow.h"
39
40 #include "lp_bld_type.h"
41 #include "lp_bld_const.h"
42 #include "lp_bld_init.h"
43 #include "lp_bld_intr.h"
44 #include "lp_bld_logic.h"
45 #include "lp_bld_pack.h"
46 #include "lp_bld_debug.h"
47 #include "lp_bld_bitarit.h"
48
49 #include "util/u_memory.h"
50 #include "util/u_debug.h"
51 #include "util/u_math.h"
52 #include "util/u_string.h"
53 #include "util/u_cpu_detect.h"
54
55 #include <float.h>
56
57
58 static LLVMValueRef
build_binary_int_overflow(struct gallivm_state * gallivm,const char * intr_prefix,LLVMValueRef a,LLVMValueRef b,LLVMValueRef * ofbit)59 build_binary_int_overflow(struct gallivm_state *gallivm,
60 const char *intr_prefix,
61 LLVMValueRef a,
62 LLVMValueRef b,
63 LLVMValueRef *ofbit)
64 {
65 LLVMBuilderRef builder = gallivm->builder;
66 char intr_str[256];
67 LLVMTypeRef type_ref;
68 LLVMTypeKind type_kind;
69 unsigned type_width;
70 LLVMTypeRef oelems[2];
71 LLVMValueRef oresult;
72 LLVMTypeRef otype;
73
74 debug_assert(LLVMTypeOf(a) == LLVMTypeOf(b));
75 type_ref = LLVMTypeOf(a);
76 type_kind = LLVMGetTypeKind(type_ref);
77
78 debug_assert(type_kind == LLVMIntegerTypeKind);
79 type_width = LLVMGetIntTypeWidth(type_ref);
80
81 debug_assert(type_width == 16 || type_width == 32 || type_width == 64);
82
83 util_snprintf(intr_str, sizeof intr_str, "%s.i%u",
84 intr_prefix, type_width);
85
86 oelems[0] = type_ref;
87 oelems[1] = LLVMInt1TypeInContext(gallivm->context);
88
89 otype = LLVMStructTypeInContext(gallivm->context, oelems, 2, FALSE);
90 oresult = lp_build_intrinsic_binary(builder, intr_str,
91 otype, a, b);
92 if (ofbit) {
93 if (*ofbit) {
94 *ofbit = LLVMBuildOr(
95 builder, *ofbit,
96 LLVMBuildExtractValue(builder, oresult, 1, ""), "");
97 } else {
98 *ofbit = LLVMBuildExtractValue(builder, oresult, 1, "");
99 }
100 }
101
102 return LLVMBuildExtractValue(builder, oresult, 0, "");
103 }
104
105 /**
106 * Performs unsigned addition of two integers and reports
107 * overflow if detected.
108 *
109 * The values @a and @b must be of the same integer type. If
110 * an overflow is detected the IN/OUT @ofbit parameter is used:
111 * - if it's pointing to a null value, the overflow bit is simply
112 * stored inside the variable it's pointing to,
113 * - if it's pointing to a valid value, then that variable,
114 * which must be of i1 type, is ORed with the newly detected
115 * overflow bit. This is done to allow chaining of a number of
116 * overflow functions together without having to test the
117 * overflow bit after every single one.
118 */
119 LLVMValueRef
lp_build_uadd_overflow(struct gallivm_state * gallivm,LLVMValueRef a,LLVMValueRef b,LLVMValueRef * ofbit)120 lp_build_uadd_overflow(struct gallivm_state *gallivm,
121 LLVMValueRef a,
122 LLVMValueRef b,
123 LLVMValueRef *ofbit)
124 {
125 return build_binary_int_overflow(gallivm, "llvm.uadd.with.overflow",
126 a, b, ofbit);
127 }
128
129 /**
130 * Performs unsigned subtraction of two integers and reports
131 * overflow if detected.
132 *
133 * The values @a and @b must be of the same integer type. If
134 * an overflow is detected the IN/OUT @ofbit parameter is used:
135 * - if it's pointing to a null value, the overflow bit is simply
136 * stored inside the variable it's pointing to,
137 * - if it's pointing to a valid value, then that variable,
138 * which must be of i1 type, is ORed with the newly detected
139 * overflow bit. This is done to allow chaining of a number of
140 * overflow functions together without having to test the
141 * overflow bit after every single one.
142 */
143 LLVMValueRef
lp_build_usub_overflow(struct gallivm_state * gallivm,LLVMValueRef a,LLVMValueRef b,LLVMValueRef * ofbit)144 lp_build_usub_overflow(struct gallivm_state *gallivm,
145 LLVMValueRef a,
146 LLVMValueRef b,
147 LLVMValueRef *ofbit)
148 {
149 return build_binary_int_overflow(gallivm, "llvm.usub.with.overflow",
150 a, b, ofbit);
151 }
152
153 /**
154 * Performs unsigned multiplication of two integers and
155 * reports overflow if detected.
156 *
157 * The values @a and @b must be of the same integer type. If
158 * an overflow is detected the IN/OUT @ofbit parameter is used:
159 * - if it's pointing to a null value, the overflow bit is simply
160 * stored inside the variable it's pointing to,
161 * - if it's pointing to a valid value, then that variable,
162 * which must be of i1 type, is ORed with the newly detected
163 * overflow bit. This is done to allow chaining of a number of
164 * overflow functions together without having to test the
165 * overflow bit after every single one.
166 */
167 LLVMValueRef
lp_build_umul_overflow(struct gallivm_state * gallivm,LLVMValueRef a,LLVMValueRef b,LLVMValueRef * ofbit)168 lp_build_umul_overflow(struct gallivm_state *gallivm,
169 LLVMValueRef a,
170 LLVMValueRef b,
171 LLVMValueRef *ofbit)
172 {
173 return build_binary_int_overflow(gallivm, "llvm.umul.with.overflow",
174 a, b, ofbit);
175 }
176