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 var X = 1.1; 31 var K = 0.5; 32 33 var O = 0; 34 var result = new Float64Array(2); 35 36 function spill() { 37 try { } catch (e) { } 38 } 39 40 function buggy() { 41 var v = X; 42 var phi1 = v + K; 43 var phi2 = v - K; 44 45 spill(); // At this point initial values for phi1 and phi2 are spilled. 46 47 var xmm1 = v; 48 var xmm2 = v*v*v; 49 var xmm3 = v*v*v*v; 50 var xmm4 = v*v*v*v*v; 51 var xmm5 = v*v*v*v*v*v; 52 var xmm6 = v*v*v*v*v*v*v; 53 var xmm7 = v*v*v*v*v*v*v*v; 54 var xmm8 = v*v*v*v*v*v*v*v*v; 55 56 // All registers are blocked and phis for phi1 and phi2 are spilled because 57 // their left (incoming) value is spilled, there are no free registers, 58 // and phis themselves have only ANY-policy uses. 59 60 for (var x = 0; x < 2; x++) { 61 xmm1 += xmm1 * xmm6; 62 xmm2 += xmm1 * xmm5; 63 xmm3 += xmm1 * xmm4; 64 xmm4 += xmm1 * xmm3; 65 xmm5 += xmm1 * xmm2; 66 67 // Now swap values of phi1 and phi2 to create cycle between phis. 68 var t = phi1; 69 phi1 = phi2; 70 phi2 = t; 71 } 72 73 // Now we want to get values of phi1 and phi2. However we would like to 74 // do it in a way that does not produce any uses of phi1&phi2 that have 75 // a register beneficial policy. How? We just hide these uses behind phis. 76 result[0] = (O === 0) ? phi1 : phi2; 77 result[1] = (O !== 0) ? phi1 : phi2; 78 } 79 80 function test() { 81 buggy(); 82 assertArrayEquals([X + K, X - K], result); 83 } 84 85 test(); 86 test(); 87 %OptimizeFunctionOnNextCall(buggy); 88 test(); 89