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[turbofan] Transform x * -1.0 to -0.0 - x.

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TEST=msjunit/asm,unittests
R=jarin@chromium.org

Review URL: https://codereview.chromium.org/683753004

Cr-Commit-Position: refs/heads/master@{#25176}
git-svn-id: https://v8.googlecode.com/svn/branches/bleeding_edge@25176 ce2b1a6d-e550-0410-aec6-3dcde31c8c00
This commit is contained in:
bmeurer@chromium.org 2014-11-06 06:13:10 +00:00
parent f3b633cc0c
commit 881cece8de
5 changed files with 63 additions and 0 deletions
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6
src/compiler/machine-operator-reducer.cc
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@ -441,6 +441,12 @@ Reduction MachineOperatorReducer::Reduce(Node* node) {
}
case IrOpcode::kFloat64Mul: {
Float64BinopMatcher m(node);
if (m.right().Is(-1)) { // x * -1.0 => -0.0 - x
node->set_op(machine()->Float64Sub());
node->ReplaceInput(0, Float64Constant(-0.0));
node->ReplaceInput(1, m.left().node());
return Changed(node);
}
if (m.right().Is(1)) return Replace(m.left().node()); // x * 1.0 => x
if (m.right().IsNaN()) { // x * NaN => NaN
return Replace(m.right().node());

33
test/mjsunit/asm/float64mul.js Normal file
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@ -0,0 +1,33 @@
// Copyright 2014 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.
function Module(stdlib, foreign, heap) {
"use asm";
function f1(i) {
i = +i;
return +(i * -1);
}
function f2(i) {
i = +i;
return +(-1 * i);
}
return { f1: f1, f2: f2 };
}
var m = Module(this, {}, new ArrayBuffer(64 * 1024));
assertEquals(NaN, m.f1(NaN));
assertEquals(NaN, m.f2(NaN));
assertEquals(Infinity, 1 / m.f1(-0));
assertEquals(Infinity, 1 / m.f2(-0));
assertEquals(Infinity, m.f1(-Infinity));
assertEquals(Infinity, m.f2(-Infinity));
assertEquals(-Infinity, 1 / m.f1(0));
assertEquals(-Infinity, 1 / m.f2(0));
assertEquals(-Infinity, m.f1(Infinity));
assertEquals(-Infinity, m.f2(Infinity));
for (var i = -2147483648; i < 2147483648; i += 3999777) {
assertEquals(-i, m.f1(i));
assertEquals(-i, m.f2(i));
}

21
test/unittests/compiler/machine-operator-reducer-unittest.cc
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@ -1106,6 +1106,27 @@ TEST_F(MachineOperatorReducerTest, Uint32LessThanWithWord32Sar) {
}
// -----------------------------------------------------------------------------
// Float64Mul
TEST_F(MachineOperatorReducerTest, Float64MulWithMinusOne) {
Node* const p0 = Parameter(0);
{
Reduction r = Reduce(
graph()->NewNode(machine()->Float64Mul(), p0, Float64Constant(-1.0)));
ASSERT_TRUE(r.Changed());
EXPECT_THAT(r.replacement(), IsFloat64Sub(IsFloat64Constant(-0.0), p0));
}
{
Reduction r = Reduce(
graph()->NewNode(machine()->Float64Mul(), Float64Constant(-1.0), p0));
ASSERT_TRUE(r.Changed());
EXPECT_THAT(r.replacement(), IsFloat64Sub(IsFloat64Constant(-0.0), p0));
}
}
// -----------------------------------------------------------------------------
// Store

1
test/unittests/compiler/node-test-utils.cc
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@ -1040,6 +1040,7 @@ IS_BINOP_MATCHER(Int32MulHigh)
IS_BINOP_MATCHER(Int32LessThan)
IS_BINOP_MATCHER(Uint32LessThan)
IS_BINOP_MATCHER(Uint32LessThanOrEqual)
IS_BINOP_MATCHER(Float64Sub)
#undef IS_BINOP_MATCHER

2
test/unittests/compiler/node-test-utils.h
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@ -156,6 +156,8 @@ Matcher<Node*> IsChangeUint32ToUint64(const Matcher<Node*>& input_matcher);
Matcher<Node*> IsTruncateFloat64ToFloat32(const Matcher<Node*>& input_matcher);
Matcher<Node*> IsTruncateFloat64ToInt32(const Matcher<Node*>& input_matcher);
Matcher<Node*> IsTruncateInt64ToInt32(const Matcher<Node*>& input_matcher);
Matcher<Node*> IsFloat64Sub(const Matcher<Node*>& lhs_matcher,
const Matcher<Node*>& rhs_matcher);
Matcher<Node*> IsFloat64Sqrt(const Matcher<Node*>& input_matcher);
Matcher<Node*> IsFloat64Floor(const Matcher<Node*>& input_matcher);
Matcher<Node*> IsFloat64Ceil(const Matcher<Node*>& input_matcher);