1 /*
2 * Copyright (c) 2013, 2014, Oracle and/or its affiliates. All rights reserved.
3 * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
4 *
5 * This code is free software; you can redistribute it and/or modify it
6 * under the terms of the GNU General Public License version 2 only, as
7 * published by the Free Software Foundation.
8 *
9 * This code is distributed in the hope that it will be useful, but WITHOUT
10 * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
11 * FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License
12 * version 2 for more details (a copy is included in the LICENSE file that
13 * accompanied this code).
14 *
15 * You should have received a copy of the GNU General Public License version
16 * 2 along with this work; if not, write to the Free Software Foundation,
17 * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
18 *
19 * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA
20 * or visit www.oracle.com if you need additional information or have any
21 * questions.
22 *
23 */
24
25 #include "precompiled.hpp"
26 #include "memory/allocation.inline.hpp"
27 #include "opto/addnode.hpp"
28 #include "opto/cfgnode.hpp"
29 #include "opto/machnode.hpp"
30 #include "opto/matcher.hpp"
31 #include "opto/mathexactnode.hpp"
32 #include "opto/subnode.hpp"
33
34 template <typename OverflowOp>
35 class AddHelper {
36 public:
37 typedef typename OverflowOp::TypeClass TypeClass;
38 typedef typename TypeClass::NativeType NativeType;
39
40 static bool will_overflow(NativeType value1, NativeType value2) {
41 NativeType result = value1 + value2;
42 // Hacker's Delight 2-12 Overflow if both arguments have the opposite sign of the result
43 if (((value1 ^ result) & (value2 ^ result)) >= 0) {
44 return false;
45 }
46 return true;
47 }
48
49 static bool can_overflow(const Type* type1, const Type* type2) {
50 if (type1 == TypeClass::ZERO || type2 == TypeClass::ZERO) {
51 return false;
52 }
53 return true;
54 }
55 };
56
57 template <typename OverflowOp>
58 class SubHelper {
59 public:
60 typedef typename OverflowOp::TypeClass TypeClass;
61 typedef typename TypeClass::NativeType NativeType;
62
63 static bool will_overflow(NativeType value1, NativeType value2) {
64 NativeType result = value1 - value2;
65 // hacker's delight 2-12 overflow iff the arguments have different signs and
66 // the sign of the result is different than the sign of arg1
67 if (((value1 ^ value2) & (value1 ^ result)) >= 0) {
68 return false;
69 }
70 return true;
71 }
72
73 static bool can_overflow(const Type* type1, const Type* type2) {
74 if (type2 == TypeClass::ZERO) {
75 return false;
76 }
77 return true;
78 }
79 };
80
81 template <typename OverflowOp>
82 class MulHelper {
83 public:
84 typedef typename OverflowOp::TypeClass TypeClass;
85
86 static bool can_overflow(const Type* type1, const Type* type2) {
87 if (type1 == TypeClass::ZERO || type2 == TypeClass::ZERO) {
88 return false;
89 } else if (type1 == TypeClass::ONE || type2 == TypeClass::ONE) {
90 return false;
91 }
92 return true;
93 }
94 };
95
96 bool OverflowAddINode::will_overflow(jint v1, jint v2) const {
97 return AddHelper<OverflowAddINode>::will_overflow(v1, v2);
98 }
99
100 bool OverflowSubINode::will_overflow(jint v1, jint v2) const {
101 return SubHelper<OverflowSubINode>::will_overflow(v1, v2);
102 }
103
104 bool OverflowMulINode::will_overflow(jint v1, jint v2) const {
105 jlong result = (jlong) v1 * (jlong) v2;
106 if ((jint) result == result) {
107 return false;
108 }
109 return true;
110 }
111
112 bool OverflowAddLNode::will_overflow(jlong v1, jlong v2) const {
113 return AddHelper<OverflowAddLNode>::will_overflow(v1, v2);
114 }
115
116 bool OverflowSubLNode::will_overflow(jlong v1, jlong v2) const {
117 return SubHelper<OverflowSubLNode>::will_overflow(v1, v2);
118 }
119
120 bool OverflowMulLNode::will_overflow(jlong val1, jlong val2) const {
121 jlong result = val1 * val2;
122 jlong ax = (val1 < 0 ? -val1 : val1);
123 jlong ay = (val2 < 0 ? -val2 : val2);
124
125 bool overflow = false;
126 if ((ax | ay) & CONST64(0xFFFFFFFF00000000)) {
127 // potential overflow if any bit in upper 32 bits are set
128 if ((val1 == min_jlong && val2 == -1) || (val2 == min_jlong && val1 == -1)) {
129 // -1 * Long.MIN_VALUE will overflow
130 overflow = true;
131 } else if (val2 != 0 && (result / val2 != val1)) {
132 overflow = true;
133 }
134 }
135
136 return overflow;
137 }
138
139 bool OverflowAddINode::can_overflow(const Type* t1, const Type* t2) const {
140 return AddHelper<OverflowAddINode>::can_overflow(t1, t2);
141 }
142
143 bool OverflowSubINode::can_overflow(const Type* t1, const Type* t2) const {
144 if (in(1) == in(2)) {
145 return false;
146 }
147 return SubHelper<OverflowSubINode>::can_overflow(t1, t2);
148 }
149
150 bool OverflowMulINode::can_overflow(const Type* t1, const Type* t2) const {
151 return MulHelper<OverflowMulINode>::can_overflow(t1, t2);
152 }
153
154 bool OverflowAddLNode::can_overflow(const Type* t1, const Type* t2) const {
155 return AddHelper<OverflowAddLNode>::can_overflow(t1, t2);
156 }
157
158 bool OverflowSubLNode::can_overflow(const Type* t1, const Type* t2) const {
159 if (in(1) == in(2)) {
160 return false;
161 }
162 return SubHelper<OverflowSubLNode>::can_overflow(t1, t2);
163 }
164
165 bool OverflowMulLNode::can_overflow(const Type* t1, const Type* t2) const {
166 return MulHelper<OverflowMulLNode>::can_overflow(t1, t2);
167 }
168
169 const Type* OverflowNode::sub(const Type* t1, const Type* t2) const {
170 fatal("sub() should not be called for '%s'", NodeClassNames[this->Opcode()]);
171 return TypeInt::CC;
172 }
173
174 template <typename OverflowOp>
175 struct IdealHelper {
176 typedef typename OverflowOp::TypeClass TypeClass; // TypeInt, TypeLong
177 typedef typename TypeClass::NativeType NativeType;
178
179 static Node* Ideal(const OverflowOp* node, PhaseGVN* phase, bool can_reshape) {
180 Node* arg1 = node->in(1);
181 Node* arg2 = node->in(2);
182 const Type* type1 = phase->type(arg1);
183 const Type* type2 = phase->type(arg2);
184
185 if (type1 == NULL || type2 == NULL) {
186 return NULL;
187 }
188
189 if (type1 != Type::TOP && type1->singleton() &&
190 type2 != Type::TOP && type2->singleton()) {
191 NativeType val1 = TypeClass::as_self(type1)->get_con();
192 NativeType val2 = TypeClass::as_self(type2)->get_con();
193 if (node->will_overflow(val1, val2) == false) {
194 Node* con_result = ConINode::make(0);
195 return con_result;
196 }
197 return NULL;
198 }
199 return NULL;
200 }
201
202 static const Type* Value(const OverflowOp* node, PhaseTransform* phase) {
203 const Type *t1 = phase->type( node->in(1) );
204 const Type *t2 = phase->type( node->in(2) );
205 if( t1 == Type::TOP ) return Type::TOP;
206 if( t2 == Type::TOP ) return Type::TOP;
207
208 const TypeClass* i1 = TypeClass::as_self(t1);
209 const TypeClass* i2 = TypeClass::as_self(t2);
210
211 if (i1 == NULL || i2 == NULL) {
212 return TypeInt::CC;
213 }
214
215 if (t1->singleton() && t2->singleton()) {
216 NativeType val1 = i1->get_con();
217 NativeType val2 = i2->get_con();
218 if (node->will_overflow(val1, val2)) {
219 return TypeInt::CC;
220 }
221 return TypeInt::ZERO;
222 } else if (i1 != TypeClass::TYPE_DOMAIN && i2 != TypeClass::TYPE_DOMAIN) {
223 if (node->will_overflow(i1->_lo, i2->_lo)) {
224 return TypeInt::CC;
225 } else if (node->will_overflow(i1->_lo, i2->_hi)) {
226 return TypeInt::CC;
227 } else if (node->will_overflow(i1->_hi, i2->_lo)) {
228 return TypeInt::CC;
229 } else if (node->will_overflow(i1->_hi, i2->_hi)) {
230 return TypeInt::CC;
231 }
232 return TypeInt::ZERO;
233 }
234
235 if (!node->can_overflow(t1, t2)) {
236 return TypeInt::ZERO;
237 }
238 return TypeInt::CC;
239 }
240 };
241
242 Node* OverflowINode::Ideal(PhaseGVN* phase, bool can_reshape) {
243 return IdealHelper<OverflowINode>::Ideal(this, phase, can_reshape);
244 }
245
246 Node* OverflowLNode::Ideal(PhaseGVN* phase, bool can_reshape) {
247 return IdealHelper<OverflowLNode>::Ideal(this, phase, can_reshape);
248 }
249
250 const Type* OverflowINode::Value(PhaseGVN* phase) const {
251 return IdealHelper<OverflowINode>::Value(this, phase);
252 }
253
254 const Type* OverflowLNode::Value(PhaseGVN* phase) const {
255 return IdealHelper<OverflowLNode>::Value(this, phase);
256 }
257