Home | History | Annotate | Download | only in compiler
      1 // Copyright 2008 the V8 project authors. All rights reserved.
      2 // Redistribution and use in source and binary forms, with or without
      3 // modification, are permitted provided that the following conditions are
      4 // met:
      5 //
      6 //     * Redistributions of source code must retain the above copyright
      7 //       notice, this list of conditions and the following disclaimer.
      8 //     * Redistributions in binary form must reproduce the above
      9 //       copyright notice, this list of conditions and the following
     10 //       disclaimer in the documentation and/or other materials provided
     11 //       with the distribution.
     12 //     * Neither the name of Google Inc. nor the names of its
     13 //       contributors may be used to endorse or promote products derived
     14 //       from this software without specific prior written permission.
     15 //
     16 // THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
     17 // "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
     18 // LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
     19 // A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
     20 // OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
     21 // SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
     22 // LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
     23 // DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
     24 // THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
     25 // (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
     26 // OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
     27 
     28 // Flags: --allow-natives-syntax
     29 // Test some dead code elimination scenarios
     30 
     31 function dead1(x, y) {
     32     var a = x | 0, b = y | 0;
     33     a * b;
     34     a << b;
     35     a >> b;
     36     a >>> b;
     37     a | b;
     38     a & b;
     39     a ^ b;
     40     return x;
     41 }
     42 
     43 function dead2(x, y) {
     44     var a = x | 0, b = y | 0;
     45     (a | 0) * b;
     46     (a | 0) << b;
     47     (a | 0) >> b;
     48     (a | 0) >>> b;
     49     (a | 0) | b;
     50     (a | 0) & b;
     51     (a | 0) ^ b;
     52     return x;
     53 }
     54 
     55 function dead3(a, b) {
     56     a == 2 ? (a * b) : (b * a); // dead
     57     return a;
     58 }
     59 
     60 assertTrue(dead1(33, 32) == 33);
     61 assertTrue(dead1(33, 32) == 33);
     62 %OptimizeFunctionOnNextCall(dead1);
     63 assertTrue(dead1(33, 32) == 33);
     64 
     65 assertTrue(dead2(34, 11) == 34);
     66 assertTrue(dead2(34, 11) == 34);
     67 %OptimizeFunctionOnNextCall(dead2);
     68 assertTrue(dead2(34, 11) == 34);
     69 
     70 assertTrue(dead3(35, 12) == 35);
     71 assertTrue(dead3(35, 12) == 35);
     72 %OptimizeFunctionOnNextCall(dead3);
     73 assertTrue(dead3(35, 12) == 35);
     74