84 lines
3.5 KiB
C++
84 lines
3.5 KiB
C++
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// 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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#include "hydrogen-minus-zero.h"
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namespace v8 {
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namespace internal {
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void HComputeMinusZeroChecksPhase::Run() {
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const ZoneList<HBasicBlock*>* blocks(graph()->blocks());
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for (int i = 0; i < blocks->length(); ++i) {
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for (HInstructionIterator it(blocks->at(i)); !it.Done(); it.Advance()) {
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HInstruction* current = it.Current();
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if (current->IsChange()) {
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HChange* change = HChange::cast(current);
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// Propagate flags for negative zero checks upwards from conversions
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// int32-to-tagged and int32-to-double.
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Representation from = change->value()->representation();
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ASSERT(from.Equals(change->from()));
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if (from.IsInteger32()) {
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ASSERT(change->to().IsTagged() ||
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change->to().IsDouble() ||
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change->to().IsSmi());
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ASSERT(visited_.IsEmpty());
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PropagateMinusZeroChecks(change->value());
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visited_.Clear();
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}
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}
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}
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}
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}
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void HComputeMinusZeroChecksPhase::PropagateMinusZeroChecks(HValue* value) {
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for (HValue* current = value;
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current != NULL && !visited_.Contains(current->id());
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current = current->EnsureAndPropagateNotMinusZero(&visited_)) {
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// For phis, we must propagate the check to all of its inputs.
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if (current->IsPhi()) {
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visited_.Add(current->id());
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HPhi* phi = HPhi::cast(current);
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for (int i = 0; i < phi->OperandCount(); ++i) {
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PropagateMinusZeroChecks(phi->OperandAt(i));
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}
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break;
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}
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// For multiplication, division, and Math.min/max(), we must propagate
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// to the left and the right side.
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if (current->IsMul() || current->IsDiv() || current->IsMathMinMax()) {
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HBinaryOperation* operation = HBinaryOperation::cast(current);
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operation->EnsureAndPropagateNotMinusZero(&visited_);
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PropagateMinusZeroChecks(operation->left());
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PropagateMinusZeroChecks(operation->right());
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}
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}
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}
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} } // namespace v8::internal
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