1 // Copyright 2013 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 30 // Presents negative opportunities for dead loop removal. 31 32 function loop1() { 33 while (true) return; 34 } 35 36 function loop2() { 37 var i = 0; 38 while (i++ < 10) ; 39 return i; // value of {i} escapes. 40 // can only remove the loop with induction variable analysis. 41 } 42 43 function loop3() { 44 var i = 0; 45 for (; i < 10; i++) ; 46 return i; // value of {i} escapes. 47 // can only remove the loop with induction variable analysis. 48 } 49 50 function loop4() { 51 var a = 0; 52 for (var i = 0; i < 10; i++) a++; 53 return a; // value of {a} escapes. 54 // can only remove the loop with induction variable analysis. 55 } 56 57 function loop5() { 58 var a = new Int32Array(4), sum = 0; 59 for (var i = 0; i < a.length; i++) { 60 sum += a[i]; 61 } 62 return sum; // {sum} escapes. 63 // can only remove the loop by figuring out that all elements of {a} are 0. 64 } 65 66 function loop6(a) { 67 for (var i = 0; i < a; i++) ; // implicit a.valueOf(). 68 // can only remove the loop by guarding on the type of a. 69 } 70 71 function loop7(a) { 72 for (var i = 0; i < 10; i++) a.toString(); // unknown side-effect on a. 73 // can only remove the loop by guarding on the type of a. 74 } 75 76 function loop8(a) { 77 for (var i = 0; i < 10; i++) a.valueOf(); // unknown side-effect on a. 78 // can only remove the loop by guarding on the type of a. 79 } 80 81 var no_params_loops = [loop1, loop2, loop3, loop4, loop5, loop6]; 82 var params_loops = [loop6, loop7, loop8]; 83 84 for (var i = 0; i < no_params_loops.length; i++) { 85 var f = no_params_loops[i]; 86 f(); 87 f(); 88 f(); 89 %OptimizeFunctionOnNextCall(f); 90 f(); 91 } 92 93 for (var i = 0; i < params_loops.length; i++) { 94 var f = params_loops[i]; 95 f(3); 96 f(7); 97 f(11); 98 %OptimizeFunctionOnNextCall(f); 99 f(9); 100 } 101
