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[turbofan] Add missing Word64->Bit support.

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The representation changer was lacking support for directly converting
Word64 values to Bit representation.

Bug: chromium:890243, v8:4153, v8:7881, v8:8171, v8:8178
Change-Id: I5fa31716c7b2b10ad00dc31d5035a1ada152661c
Reviewed-on: https://chromium-review.googlesource.com/1251551
Reviewed-by: Jaroslav Sevcik <jarin@chromium.org>
Commit-Queue: Benedikt Meurer <bmeurer@chromium.org>
Cr-Commit-Position: refs/heads/master@{#56304}
This commit is contained in:
Benedikt Meurer 2018-09-28 19:23:52 +02:00 committed by Commit Bot
parent c285380ca8
commit 852a8d35b9
2 changed files with 32 additions and 0 deletions
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5
src/compiler/representation-change.cc
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@ -919,6 +919,11 @@ Node* RepresentationChanger::GetBitRepresentationFor(
jsgraph()->Int32Constant(0));
return jsgraph()->graph()->NewNode(machine()->Word32Equal(), node,
jsgraph()->Int32Constant(0));
} else if (output_rep == MachineRepresentation::kWord64) {
node = jsgraph()->graph()->NewNode(machine()->Word64Equal(), node,
jsgraph()->Int64Constant(0));
return jsgraph()->graph()->NewNode(machine()->Word32Equal(), node,
jsgraph()->Int32Constant(0));
} else if (output_rep == MachineRepresentation::kFloat32) {
node = jsgraph()->graph()->NewNode(machine()->Float32Abs(), node);
return jsgraph()->graph()->NewNode(machine()->Float32LessThan(),

27
test/mjsunit/regress/regress-crbug-890243.js Normal file
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@ -0,0 +1,27 @@
// Copyright 2018 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
// We need a SpeculativeNumberAdd with Number feedback.
function bar(x) { return x + x; }
bar(0.1);
// We also need an indirection via an object field such
// that only after escape analysis TurboFan can figure
// out that the value `y` is actually a Number in the
// safe integer range.
function baz(y) { return {y}; }
baz(null); baz(0);
// Now we can put all of that together to get a kRepBit
// use of a kWord64 value (on 64-bit architectures).
function foo(o) {
return !baz(bar(o.x)).y;
}
assertFalse(foo({x:1}));
assertFalse(foo({x:1}));
%OptimizeFunctionOnNextCall(foo);
assertFalse(foo({x:1}));