Merge the "Compute Minus Zero Checks" phase into the range analysis.

src/hydrogen-minus-zero.cc

-// 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());
-          PropagateMinusZeroChecks(change->value());
-        }
-      } else if (current->IsCompareMinusZeroAndBranch()) {
-        HCompareMinusZeroAndBranch* check =
-            HCompareMinusZeroAndBranch::cast(current);
-        if (check->value()->representation().IsSmiOrInteger32()) {
-          PropagateMinusZeroChecks(check->value());
-        }
-      }
-    }
-  }
-}
-
-
-void HComputeMinusZeroChecksPhase::PropagateMinusZeroChecks(HValue* value) {
-  ASSERT(worklist_.is_empty());
-  ASSERT(in_worklist_.IsEmpty());
-
-  AddToWorklist(value);
-  while (!worklist_.is_empty()) {
-    value = worklist_.RemoveLast();
-
-    if (value->IsPhi()) {
-      // For phis, we must propagate the check to all of its inputs.
-      HPhi* phi = HPhi::cast(value);
-      for (int i = 0; i < phi->OperandCount(); ++i) {
-        AddToWorklist(phi->OperandAt(i));
-      }
-    } else if (value->IsUnaryMathOperation()) {
-      HUnaryMathOperation* instr = HUnaryMathOperation::cast(value);
-      if (instr->representation().IsSmiOrInteger32() &&
-          !instr->value()->representation().Equals(instr->representation())) {
-        if (instr->value()->range() == NULL ||
-            instr->value()->range()->CanBeMinusZero()) {
-          instr->SetFlag(HValue::kBailoutOnMinusZero);
-        }
-      }
-      if (instr->RequiredInputRepresentation(0).IsSmiOrInteger32() &&
-          instr->representation().Equals(
-              instr->RequiredInputRepresentation(0))) {
-        AddToWorklist(instr->value());
-      }
-    } else if (value->IsChange()) {
-      HChange* instr = HChange::cast(value);
-      if (!instr->from().IsSmiOrInteger32() &&
-          !instr->CanTruncateToInt32() &&
-          (instr->value()->range() == NULL ||
-           instr->value()->range()->CanBeMinusZero())) {
-        instr->SetFlag(HValue::kBailoutOnMinusZero);
-      }
-    } else if (value->IsForceRepresentation()) {
-      HForceRepresentation* instr = HForceRepresentation::cast(value);
-      AddToWorklist(instr->value());
-    } else if (value->IsMod()) {
-      HMod* instr = HMod::cast(value);
-      if (instr->range() == NULL || instr->range()->CanBeMinusZero()) {
-        instr->SetFlag(HValue::kBailoutOnMinusZero);
-        AddToWorklist(instr->left());
-      }
-    } else if (value->IsDiv() || value->IsMul()) {
-      HBinaryOperation* instr = HBinaryOperation::cast(value);
-      if (instr->range() == NULL || instr->range()->CanBeMinusZero()) {
-        instr->SetFlag(HValue::kBailoutOnMinusZero);
-      }
-      AddToWorklist(instr->right());
-      AddToWorklist(instr->left());
-    } else if (value->IsMathFloorOfDiv()) {
-      HMathFloorOfDiv* instr = HMathFloorOfDiv::cast(value);
-      instr->SetFlag(HValue::kBailoutOnMinusZero);
-    } else if (value->IsAdd() || value->IsSub()) {
-      HBinaryOperation* instr = HBinaryOperation::cast(value);
-      if (instr->range() == NULL || instr->range()->CanBeMinusZero()) {
-        // Propagate to the left argument. If the left argument cannot be -0,
-        // then the result of the add/sub operation cannot be either.
-        AddToWorklist(instr->left());
-      }
-    } else if (value->IsMathMinMax()) {
-      HMathMinMax* instr = HMathMinMax::cast(value);
-      AddToWorklist(instr->right());
-      AddToWorklist(instr->left());
-    }
-  }
-
-  in_worklist_.Clear();
-  ASSERT(in_worklist_.IsEmpty());
-  ASSERT(worklist_.is_empty());
-}
-
-} }  // namespace v8::internal