// Copyright 2013 the V8 project authors. All rights reserved. // Redistribution and use in source and binary forms, with or without // modification, are permitted provided that the following conditions are // met: // // * Redistributions of source code must retain the above copyright // notice, this list of conditions and the following disclaimer. // * Redistributions in binary form must reproduce the above // copyright notice, this list of conditions and the following // disclaimer in the documentation and/or other materials provided // with the distribution. // * Neither the name of Google Inc. nor the names of its // contributors may be used to endorse or promote products derived // from this software without specific prior written permission. // // THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS // "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT // LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR // A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT // OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, // SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT // LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, // DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY // THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT // (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE // OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE. // Flags: --allow-natives-syntax // Presents opportunities for dead loop removal. function loop1() { while (false) ; // doesn't even loop. } function loop2() { var i = 0; while (i++ < 10) ; // nothing in the body. } function loop3() { for (var i = 0; i < 10; i++) ; // nothing in the body. } function loop4() { var a = 0; for (var i = 0; i < 10; i++) a++; // {a} is dead after the loop. } function loop5() { var a = new Int32Array(4), sum = 0; for (var i = 0; i < a.length; i++) { // Involves only reads on typed arrays, and {i} doesn't overflow. sum += a[i]; } } function loop6() { var a = new Array(4), sum = 0; for (var i = 0; i < a.length; i++) { // Involves only in-bounds read on the array {a}. // Have to prove that {a} doesn't have getters...? sum += a[i]; } } function loop7() { for (var i = 0; i < 10; i++) { new Object(); // Have to prove the allocation doesn't escape. } } function loop8() { for (var i = 0; i < 10; i++) { var x = {}; // Have to prove the allocation doesn't escape. } } var loops = [loop1, loop2, loop3, loop4, loop5, loop6, loop7, loop8]; for (var i = 0; i < loops.length; i++) { var f = loops[i]; %PrepareFunctionForOptimization(f); f(); f(); %OptimizeFunctionOnNextCall(f); f(); }