src/v8/test/webkit/dfg-cse-cfa-discrepancy.js

// Copyright 2013 the V8 project authors. All rights reserved.
// Copyright (C) 2005, 2006, 2007, 2008, 2009 Apple Inc. All rights reserved.
//
// Redistribution and use in source and binary forms, with or without
// modification, are permitted provided that the following conditions
// are met:
// 1.  Redistributions of source code must retain the above copyright
//     notice, this list of conditions and the following disclaimer.
// 2.  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.
//
// THIS SOFTWARE IS PROVIDED BY APPLE INC. AND ITS 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 APPLE INC. OR ITS 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.

description(
"Tests stability when the CFA finds a constant in block-local data flow over captured variables but the CSE doesn't because of differences in heap modeling."
);

function foo(a, b) {
    var x = a + b;
    var y = a - b;
    function bar() {
        var m = x + y;
        var n = x - y;
        function baz() {
            return m + n;
        }
        m = 23;
        if (m < n) {
            m = 12;
            y = 72; // PutScopedVar appears to clobber world in CSE but only clobbers structures in CFA.
            return m + 6 + n + baz();
        } else
            return 91;
    }
    x = 42;
    if (y < 0) {
        return x + 5 + y + bar();
    } else
        return 73;
}

for (var i = 0; i < 200; ++i)
    shouldBe("foo(i, i + 1)", "162");