Ben Murdoch | b8a8cc1 | 2014-11-26 15:28:44 +0000 | [diff] [blame] | 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 | } |