1 /*
2  * Copyright (C) 2015 The Android Open Source Project
3  *
4  * Licensed under the Apache License, Version 2.0 (the "License");
5  * you may not use this file except in compliance with the License.
6  * You may obtain a copy of the License at
7  *
8  *      http://www.apache.org/licenses/LICENSE-2.0
9  *
10  * Unless required by applicable law or agreed to in writing, software
11  * distributed under the License is distributed on an "AS IS" BASIS,
12  * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
13  * See the License for the specific language governing permissions and
14  * limitations under the License.
15  */
16 
17 public class Main {
18 
19   /// CHECK-START: Main Main.keepTest(Main) instruction_simplifier (before)
20   /// CHECK:         NullCheck
21   /// CHECK:         InvokeStaticOrDirect
22 
23   /// CHECK-START: Main Main.keepTest(Main) instruction_simplifier (after)
24   /// CHECK:         NullCheck
25   /// CHECK:         InvokeStaticOrDirect
keepTest(Main m)26   public Main keepTest(Main m) {
27     return m.g();
28   }
29 
30   /// CHECK-START: Main Main.thisTest() builder (after)
31   /// CHECK-NOT:     NullCheck
32   /// CHECK:         InvokeStaticOrDirect
thisTest()33   public Main thisTest() {
34     return g();
35   }
36 
37   /// CHECK-START: Main Main.newInstanceRemoveTest() builder (after)
38   /// CHECK:         NewInstance
39   /// CHECK:         InvokeStaticOrDirect
40   /// CHECK:         InvokeStaticOrDirect
41 
42   /// CHECK-START: Main Main.newInstanceRemoveTest() builder (after)
43   /// CHECK-NOT:     NullCheck
newInstanceRemoveTest()44   public Main newInstanceRemoveTest() {
45     Main m = new Main();
46     return m.g();
47   }
48 
49   /// CHECK-START: Main Main.newArrayRemoveTest() builder (after)
50   /// CHECK:         NewArray
51   /// CHECK:         ArrayGet
52 
53   /// CHECK-START: Main Main.newArrayRemoveTest() builder (after)
54   /// CHECK-NOT:     NullCheck
newArrayRemoveTest()55   public Main newArrayRemoveTest() {
56     Main[] ms = new Main[1];
57     return ms[0];
58   }
59 
60   /// CHECK-START: Main Main.ifRemoveTest(boolean) instruction_simplifier (before)
61   /// CHECK:         NewInstance
62   /// CHECK:         NullCheck
63 
64   /// CHECK-START: Main Main.ifRemoveTest(boolean) instruction_simplifier (after)
65   /// CHECK:         NewInstance
66   /// CHECK-NOT:     NullCheck
ifRemoveTest(boolean flag)67   public Main ifRemoveTest(boolean flag) {
68     Main m = null;
69     if (flag) {
70       m = new Main();
71     } else {
72       m = new Main(1);
73     }
74     return m.g();
75   }
76 
77   /// CHECK-START: Main Main.ifKeepTest(boolean) instruction_simplifier (before)
78   /// CHECK:         NewInstance
79   /// CHECK:         NullCheck
80 
81   /// CHECK-START: Main Main.ifKeepTest(boolean) instruction_simplifier (after)
82   /// CHECK:         NewInstance
83   /// CHECK:         NullCheck
ifKeepTest(boolean flag)84   public Main ifKeepTest(boolean flag) {
85     Main m = null;
86     if (flag) {
87       m = new Main(1);
88     }
89     return m.g();
90   }
91 
92   /// CHECK-START: Main Main.forRemoveTest(int) instruction_simplifier (before)
93   /// CHECK:         NullCheck
94 
95   /// CHECK-START: Main Main.forRemoveTest(int) instruction_simplifier (after)
96   /// CHECK-NOT:     NullCheck
forRemoveTest(int count)97   public Main forRemoveTest(int count) {
98     Main a = new Main();
99     Main m = new Main();
100     for (int i = 0; i < count; i++) {
101       if (i % 2 == 0) {
102         m = a;
103       }
104     }
105     return m.g();
106   }
107 
108   /// CHECK-START: Main Main.forKeepTest(int) instruction_simplifier (before)
109   /// CHECK:         NullCheck
110 
111   /// CHECK-START: Main Main.forKeepTest(int) instruction_simplifier (after)
112   /// CHECK:         NullCheck
forKeepTest(int count)113   public Main forKeepTest(int count) {
114     Main a = new Main();
115     Main m = new Main();
116     for (int i = 0; i < count; i++) {
117       if (i % 2 == 0) {
118         m = a;
119       } else {
120         m = null;
121       }
122     }
123     return m.g();
124   }
125 
126   /// CHECK-START: Main Main.phiFlowRemoveTest(int) instruction_simplifier (before)
127   /// CHECK:         NullCheck
128 
129   /// CHECK-START: Main Main.phiFlowRemoveTest(int) instruction_simplifier (after)
130   /// CHECK-NOT:     NullCheck
phiFlowRemoveTest(int count)131   public Main phiFlowRemoveTest(int count) {
132     Main a = new Main();
133     Main m = new Main();
134     for (int i = 0; i < count; i++) {
135       if (i % 2 == 0) {
136         m = a;
137       }
138     }
139     Main n = new Main();
140     for (int i = 0; i < count; i++) {
141       if (i % 3 == 0) {
142         n = m;
143       }
144     }
145     return n.g();
146   }
147 
148   /// CHECK-START: Main Main.phiFlowKeepTest(int) instruction_simplifier (before)
149   /// CHECK:         NullCheck
150 
151   /// CHECK-START: Main Main.phiFlowKeepTest(int) instruction_simplifier (after)
152   /// CHECK:         NullCheck
phiFlowKeepTest(int count)153   public Main phiFlowKeepTest(int count) {
154     Main a = new Main();
155     Main m = new Main();
156     for (int i = 0; i < count; i++) {
157       if (i % 2 == 0) {
158         m = a;
159       } else {
160         m = null;
161       }
162     }
163     Main n = new Main();
164     for (int i = 0; i < count; i++) {
165       if (i % 3 == 0) {
166         n = m;
167       }
168     }
169     return n.g();
170   }
171 
172   /// CHECK-START: Main Main.scopeRemoveTest(int, Main) builder (after)
173   /// CHECK-NOT:     NullCheck
scopeRemoveTest(int count, Main a)174   public Main scopeRemoveTest(int count, Main a) {
175     Main m = null;
176     for (int i = 0; i < count; i++) {
177       if (i % 2 == 0) {
178         m = new Main();
179         m.g();
180       } else {
181         m = a;
182       }
183     }
184     return m;
185   }
186 
187   /// CHECK-START: Main Main.scopeKeepTest(int, Main) instruction_simplifier (before)
188   /// CHECK:         NullCheck
189 
190   /// CHECK-START: Main Main.scopeKeepTest(int, Main) instruction_simplifier (after)
191   /// CHECK:         NullCheck
scopeKeepTest(int count, Main a)192   public Main scopeKeepTest(int count, Main a) {
193     Main m = new Main();
194     for (int i = 0; i < count; i++) {
195       if (i % 2 == 0) {
196         m = a;
197       } else {
198         m = a;
199         m.g();
200       }
201     }
202     return m;
203   }
204 
205   /// CHECK-START: Main Main.scopeIfNotNullRemove(Main) instruction_simplifier (before)
206   /// CHECK:         NullCheck
207 
208   /// CHECK-START: Main Main.scopeIfNotNullRemove(Main) instruction_simplifier (after)
209   /// CHECK-NOT:     NullCheck
scopeIfNotNullRemove(Main m)210   public Main scopeIfNotNullRemove(Main m) {
211     if (m != null) {
212       return m.g();
213     }
214     return m;
215   }
216 
217   /// CHECK-START: Main Main.scopeIfKeep(Main) instruction_simplifier (before)
218   /// CHECK:         NullCheck
219 
220   /// CHECK-START: Main Main.scopeIfKeep(Main) instruction_simplifier (after)
221   /// CHECK:         NullCheck
scopeIfKeep(Main m)222   public Main scopeIfKeep(Main m) {
223     if (m == null) {
224       m = new Main();
225     }
226     return m.g();
227   }
228 
Main()229   public Main() {}
Main(int dummy)230   public Main(int dummy) {}
231 
g()232   private Main g() {
233     // avoids inlining
234     throw new RuntimeException();
235   }
236 
main(String[] args)237   public static void main(String[] args) {
238     new Main();
239   }
240 
241 }
242 
243 // Regression for when we created and kept equivalent phis with the same type.
244 // The phi used in comparison would be different then the one used for access
245 // so we could not safely discard it.
246 class ListElement {
247   private ListElement next;
248 
249   /// CHECK-START: boolean ListElement.isShorter(ListElement, ListElement) instruction_simplifier (before)
250   /// CHECK:         NullCheck
251   /// CHECK:         NullCheck
252 
253   /// CHECK-START: boolean ListElement.isShorter(ListElement, ListElement) instruction_simplifier (after)
254   /// CHECK-NOT:     NullCheck
isShorter(ListElement x, ListElement y)255   static boolean isShorter(ListElement x, ListElement y) {
256     ListElement xTail = x;
257     ListElement yTail = y;
258     while (yTail != null) {
259       if (xTail == null) return true;
260       xTail = xTail.next;
261       yTail = yTail.next;
262     }
263     return false;
264   }
265 }
266