b190d13331
At the moment, two NumberConstant nodes get different type even if their value is the same because we always allocate a new heap number for each number constant. This can lead to replacing a node with a node of disjoint type in value numbering, which can result in incorrect code down the line because of inconsistent types. This fix makes sure that we only replace a node with a sub-type node. Once we introduce a proper type for number constants, we can move back to the intersection typing in value numbering. Unfortunately, it is quite hard to write a repro for this because we cache NumberConstant nodes. We only throw away cached values that have too many conflicts (>5), so the test has to contain values that fall into the same bucket. That's where the magic floating point numbers in the test come from (they have the same low 8-bits of their hashes). BUG=chromium:633497 Review-Url: https://codereview.chromium.org/2251833002 Cr-Commit-Position: refs/heads/master@{#38675}
30 lines
530 B
JavaScript
30 lines
530 B
JavaScript
// Copyright 2016 the V8 project authors. All rights reserved.
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// Use of this source code is governed by a BSD-style license that can be
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// found in the LICENSE file.
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// Flags: --allow-natives-syntax
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function f(a) {
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var x;
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a = a|0;
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var dummy;
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if (a === 1) {
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x = 277.5;
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} else if (a === 2) {
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x = 0;
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} else {
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dummy = 527.5;
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dummy = 958.5;
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dummy = 1143.5;
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dummy = 1368.5;
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dummy = 1558.5;
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x = 277.5;
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}
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return +x;
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}
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f();
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f();
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%OptimizeFunctionOnNextCall(f);
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assertEquals(277.5, f());
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