| // Copyright 2013 the V8 project authors. All rights reserved. |
| // Redistribution and use in source and binary forms, with or without |
| // modification, are permitted provided that the following conditions are |
| // met: |
| // |
| // * Redistributions of source code must retain the above copyright |
| // notice, this list of conditions and the following disclaimer. |
| // * Redistributions in binary form must reproduce the above |
| // copyright notice, this list of conditions and the following |
| // disclaimer in the documentation and/or other materials provided |
| // with the distribution. |
| // * Neither the name of Google Inc. nor the names of its |
| // contributors may be used to endorse or promote products derived |
| // from this software without specific prior written permission. |
| // |
| // THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS |
| // "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT |
| // LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR |
| // A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT |
| // OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, |
| // SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT |
| // LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, |
| // DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY |
| // THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT |
| // (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE |
| // OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE. |
| |
| #include "hydrogen-minus-zero.h" |
| |
| namespace v8 { |
| namespace internal { |
| |
| void HComputeMinusZeroChecksPhase::Run() { |
| const ZoneList<HBasicBlock*>* blocks(graph()->blocks()); |
| for (int i = 0; i < blocks->length(); ++i) { |
| for (HInstructionIterator it(blocks->at(i)); !it.Done(); it.Advance()) { |
| HInstruction* current = it.Current(); |
| if (current->IsChange()) { |
| HChange* change = HChange::cast(current); |
| // Propagate flags for negative zero checks upwards from conversions |
| // int32-to-tagged and int32-to-double. |
| Representation from = change->value()->representation(); |
| ASSERT(from.Equals(change->from())); |
| if (from.IsSmiOrInteger32()) { |
| ASSERT(change->to().IsTagged() || |
| change->to().IsDouble() || |
| change->to().IsSmiOrInteger32()); |
| ASSERT(visited_.IsEmpty()); |
| PropagateMinusZeroChecks(change->value()); |
| visited_.Clear(); |
| } |
| } else if (current->IsCompareMinusZeroAndBranch()) { |
| HCompareMinusZeroAndBranch* check = |
| HCompareMinusZeroAndBranch::cast(current); |
| if (check->value()->representation().IsSmiOrInteger32()) { |
| ASSERT(visited_.IsEmpty()); |
| PropagateMinusZeroChecks(check->value()); |
| visited_.Clear(); |
| } |
| } |
| } |
| } |
| } |
| |
| |
| void HComputeMinusZeroChecksPhase::PropagateMinusZeroChecks(HValue* value) { |
| for (HValue* current = value; |
| current != NULL && !visited_.Contains(current->id()); |
| current = current->EnsureAndPropagateNotMinusZero(&visited_)) { |
| // For phis, we must propagate the check to all of its inputs. |
| if (current->IsPhi()) { |
| visited_.Add(current->id()); |
| HPhi* phi = HPhi::cast(current); |
| for (int i = 0; i < phi->OperandCount(); ++i) { |
| PropagateMinusZeroChecks(phi->OperandAt(i)); |
| } |
| break; |
| } |
| |
| // For multiplication, division, and Math.min/max(), we must propagate |
| // to the left and the right side. |
| if (current->IsMul() || current->IsDiv() || current->IsMathMinMax()) { |
| HBinaryOperation* operation = HBinaryOperation::cast(current); |
| operation->EnsureAndPropagateNotMinusZero(&visited_); |
| PropagateMinusZeroChecks(operation->left()); |
| PropagateMinusZeroChecks(operation->right()); |
| } |
| } |
| } |
| |
| } } // namespace v8::internal |