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
58static LLVMValueRef
59build_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   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 */
119LLVMValueRef
120lp_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 */
143LLVMValueRef
144lp_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 */
167LLVMValueRef
168lp_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