31a3cfbc10
BUG=v8:8801 Change-Id: I9d9d9824c6c9ad0176bbfd3723da1b578b17c256 Reviewed-on: https://chromium-review.googlesource.com/c/1495555 Commit-Queue: Ross McIlroy <rmcilroy@chromium.org> Reviewed-by: Mythri Alle <mythria@chromium.org> Cr-Commit-Position: refs/heads/master@{#60001}
89 lines
2.8 KiB
JavaScript
89 lines
2.8 KiB
JavaScript
// Copyright 2013 the V8 project authors. All rights reserved.
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// Redistribution and use in source and binary forms, with or without
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// modification, are permitted provided that the following conditions are
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// met:
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//
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// * Redistributions of source code must retain the above copyright
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// notice, this list of conditions and the following disclaimer.
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// * Redistributions in binary form must reproduce the above
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// copyright notice, this list of conditions and the following
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// disclaimer in the documentation and/or other materials provided
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// with the distribution.
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// * Neither the name of Google Inc. nor the names of its
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// contributors may be used to endorse or promote products derived
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// from this software without specific prior written permission.
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//
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// THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
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// "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
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// LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
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// A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
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// OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
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// SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
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// LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
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// DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
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// THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
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// (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
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// OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
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// Flags: --allow-natives-syntax
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// Presents opportunities for dead loop removal.
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function loop1() {
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while (false) ; // doesn't even loop.
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}
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function loop2() {
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var i = 0;
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while (i++ < 10) ; // nothing in the body.
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}
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function loop3() {
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for (var i = 0; i < 10; i++) ; // nothing in the body.
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}
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function loop4() {
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var a = 0;
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for (var i = 0; i < 10; i++) a++; // {a} is dead after the loop.
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}
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function loop5() {
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var a = new Int32Array(4), sum = 0;
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for (var i = 0; i < a.length; i++) {
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// Involves only reads on typed arrays, and {i} doesn't overflow.
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sum += a[i];
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}
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}
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function loop6() {
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var a = new Array(4), sum = 0;
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for (var i = 0; i < a.length; i++) {
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// Involves only in-bounds read on the array {a}.
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// Have to prove that {a} doesn't have getters...?
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sum += a[i];
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}
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}
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function loop7() {
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for (var i = 0; i < 10; i++) {
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new Object(); // Have to prove the allocation doesn't escape.
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}
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}
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function loop8() {
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for (var i = 0; i < 10; i++) {
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var x = {}; // Have to prove the allocation doesn't escape.
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}
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}
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var loops = [loop1, loop2, loop3, loop4, loop5, loop6, loop7, loop8];
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for (var i = 0; i < loops.length; i++) {
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var f = loops[i];
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%PrepareFunctionForOptimization(f);
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f();
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f();
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%OptimizeFunctionOnNextCall(f);
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f();
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}
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