Refactor compute minus zero checks into a proper HPhase.

R=dslomov@chromium.org

Review URL: https://codereview.chromium.org/18666006

git-svn-id: http://v8.googlecode.com/svn/branches/bleeding_edge@15595 ce2b1a6d-e550-0410-aec6-3dcde31c8c00

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.IsInteger32()) {
+          ASSERT(change->to().IsTagged() ||
+                 change->to().IsDouble() ||
+                 change->to().IsSmi());
+          ASSERT(visited_.IsEmpty());
+          PropagateMinusZeroChecks(change->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

src/hydrogen-minus-zero.h

+// 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.
+
+#ifndef V8_HYDROGEN_MINUS_ZERO_H_
+#define V8_HYDROGEN_MINUS_ZERO_H_
+
+#include "hydrogen.h"
+
+namespace v8 {
+namespace internal {
+
+
+class HComputeMinusZeroChecksPhase : public HPhase {
+ public:
+  explicit HComputeMinusZeroChecksPhase(HGraph* graph)
+      : HPhase("H_Compute minus zero checks", graph),
+        visited_(graph->GetMaximumValueID(), zone()) { }
+
+  void Run();
+
+ private:
+  void PropagateMinusZeroChecks(HValue* value);
+
+  BitVector visited_;
+
+  DISALLOW_COPY_AND_ASSIGN(HComputeMinusZeroChecksPhase);
+};
+
+
+} }  // namespace v8::internal
+
+#endif  // V8_HYDROGEN_MINUS_ZERO_H_

src/hydrogen.cc

@@ -40,6 +40,7 @@
 #include "hydrogen-infer-representation.h"
 #include "hydrogen-infer-types.h"
 #include "hydrogen-gvn.h"
+#include "hydrogen-minus-zero.h"
 #include "hydrogen-osr.h"
 #include "hydrogen-range-analysis.h"
 #include "hydrogen-redundant-phi.h"
@@ -2634,45 +2635,6 @@ void HGraph::MergeRemovableSimulates() {
 }
 
 
-void HGraph::PropagateMinusZeroChecks(HValue* value, BitVector* visited) {
-  HValue* current = value;
-  while (current != NULL) {
-    if (visited->Contains(current->id())) return;
-
-    // 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), visited);
-      }
-      break;
-    }
-
-    // For multiplication, division, and Math.min/max(), we must propagate
-    // to the left and the right side.
-    if (current->IsMul()) {
-      HMul* mul = HMul::cast(current);
-      mul->EnsureAndPropagateNotMinusZero(visited);
-      PropagateMinusZeroChecks(mul->left(), visited);
-      PropagateMinusZeroChecks(mul->right(), visited);
-    } else if (current->IsDiv()) {
-      HDiv* div = HDiv::cast(current);
-      div->EnsureAndPropagateNotMinusZero(visited);
-      PropagateMinusZeroChecks(div->left(), visited);
-      PropagateMinusZeroChecks(div->right(), visited);
-    } else if (current->IsMathMinMax()) {
-      HMathMinMax* minmax = HMathMinMax::cast(current);
-      visited->Add(minmax->id());
-      PropagateMinusZeroChecks(minmax->left(), visited);
-      PropagateMinusZeroChecks(minmax->right(), visited);
-    }
-
-    current = current->EnsureAndPropagateNotMinusZero(visited);
-  }
-}
-
-
 void HGraph::RecursivelyMarkPhiDeoptimizeOnUndefined(HPhi* phi) {
   if (!phi->CheckFlag(HValue::kAllowUndefinedAsNaN)) return;
   phi->ClearFlag(HValue::kAllowUndefinedAsNaN);
@@ -2705,32 +2667,6 @@ void HGraph::MarkDeoptimizeOnUndefined() {
 }
 
 
-void HGraph::ComputeMinusZeroChecks() {
-  HPhase phase("H_Compute minus zero checks", this);
-  BitVector visited(GetMaximumValueID(), zone());
-  for (int i = 0; i < blocks_.length(); ++i) {
-    for (HInstructionIterator it(blocks_[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.IsInteger32()) {
-          ASSERT(change->to().IsTagged() ||
-                 change->to().IsDouble() ||
-                 change->to().IsSmi());
-          ASSERT(visited.IsEmpty());
-          PropagateMinusZeroChecks(change->value(), &visited);
-          visited.Clear();
-        }
-      }
-    }
-  }
-}
-
-
 // Implementation of utility class to encapsulate the translation state for
 // a (possibly inlined) function.
 FunctionState::FunctionState(HOptimizedGraphBuilder* owner,
@@ -3221,7 +3157,7 @@ bool HGraph::Optimize(SmartArrayPointer<char>* bailout_reason) {
 
   if (FLAG_use_range) Run<HRangeAnalysisPhase>();
 
-  ComputeMinusZeroChecks();
+  Run<HComputeMinusZeroChecksPhase>();
 
   // Eliminate redundant stack checks on backwards branches.
   Run<HStackCheckEliminationPhase>();

src/hydrogen.h

@@ -294,7 +294,6 @@ class HGraph: public ZoneObject {
   void InsertTypeConversions();
   void MergeRemovableSimulates();
   void MarkDeoptimizeOnUndefined();
-  void ComputeMinusZeroChecks();
   bool ProcessArgumentsObject();
   void Canonicalize();
   void OrderBlocks();
@@ -449,7 +448,6 @@ class HGraph: public ZoneObject {
   void MarkAsDeoptimizingRecursively(HBasicBlock* block);
   void NullifyUnreachableInstructions();
   void InsertTypeConversions(HInstruction* instr);
-  void PropagateMinusZeroChecks(HValue* value, BitVector* visited);
   void RecursivelyMarkPhiDeoptimizeOnUndefined(HPhi* phi);
   void CheckForBackEdge(HBasicBlock* block, HBasicBlock* successor);
   void SetupInformativeDefinitionsInBlock(HBasicBlock* block);

tools/gyp/v8.gyp

@@ -353,6 +353,8 @@
         '../../src/hydrogen-infer-representation.h',
         '../../src/hydrogen-infer-types.cc',
         '../../src/hydrogen-infer-types.h',
+        '../../src/hydrogen-minus-zero.cc',
+        '../../src/hydrogen-minus-zero.h',
         '../../src/hydrogen-range-analysis.cc',
         '../../src/hydrogen-range-analysis.h',
         '../../src/hydrogen-redundant-phi.cc',