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[turbofan] Fix typed lowering of JSToLength.

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When lowering JSToLength, we cannot just smash arbitrary bounds on the
Select nodes, as that will confuse the representation selection later.
Instead properly rename the input using NumberMax and NumberMin.

R=jarin@chromium.org
BUG=chromium:657478

Review-Url: https://codereview.chromium.org/2440333002
Cr-Commit-Position: refs/heads/master@{#40519}
This commit is contained in:
bmeurer 2016-10-23 23:36:41 -07:00 committed by Commit bot
parent a2d4a7932e
commit a58d7907ea
2 changed files with 17 additions and 15 deletions
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19
src/compiler/js-typed-lowering.cc
View File

@ -983,23 +983,12 @@ Reduction JSTypedLowering::ReduceJSToLength(Node* node) {
input = jsgraph()->Constant(kMaxSafeInteger);
} else {
if (input_type->Min() <= 0.0) {
input = graph()->NewNode(
common()->Select(MachineRepresentation::kTagged),
graph()->NewNode(simplified()->NumberLessThanOrEqual(), input,
jsgraph()->ZeroConstant()),
jsgraph()->ZeroConstant(), input);
input_type = Type::Range(0.0, input_type->Max(), graph()->zone());
NodeProperties::SetType(input, input_type);
input = graph()->NewNode(simplified()->NumberMax(),
jsgraph()->ZeroConstant(), input);
}
if (input_type->Max() > kMaxSafeInteger) {
input = graph()->NewNode(
common()->Select(MachineRepresentation::kTagged),
graph()->NewNode(simplified()->NumberLessThanOrEqual(),
jsgraph()->Constant(kMaxSafeInteger), input),
jsgraph()->Constant(kMaxSafeInteger), input);
input_type =
Type::Range(input_type->Min(), kMaxSafeInteger, graph()->zone());
NodeProperties::SetType(input, input_type);
input = graph()->NewNode(simplified()->NumberMin(),
jsgraph()->Constant(kMaxSafeInteger), input);
}
}
ReplaceWithValue(node, input);

13
test/mjsunit/regress/regress-crbug-657478.js Normal file
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@ -0,0 +1,13 @@
// Copyright 2016 the V8 project authors. All rights reserved.
// Use of this source code is governed by a BSD-style license that can be
// found in the LICENSE file.
// Flags: --allow-natives-syntax
function foo(o) { return %_ToLength(o.length); }
foo(new Array(4));
foo(new Array(Math.pow(2, 32) - 1));
foo({length: 10});
%OptimizeFunctionOnNextCall(foo);
foo({length: 10});