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

It is not safe to access the range for an SSA value
after range analysis.

BUG=v8:3204
LOG=y
R=svenpanne@chromium.org

Review URL: https://codereview.chromium.org/192673002

git-svn-id: http://v8.googlecode.com/svn/branches/bleeding_edge@19751 ce2b1a6d-e550-0410-aec6-3dcde31c8c00

src/flag-definitions.h

@@ -241,7 +241,6 @@ DEFINE_bool(string_slices, true, "use string slices")
 // Flags for Crankshaft.
 DEFINE_bool(crankshaft, true, "use crankshaft")
 DEFINE_string(hydrogen_filter, "*", "optimization filter")
-DEFINE_bool(use_range, true, "use hydrogen range analysis")
 DEFINE_bool(use_gvn, true, "use hydrogen global value numbering")
 DEFINE_int(gvn_iterations, 3, "maximum number of GVN fix-point iterations")
 DEFINE_bool(use_canonicalizing, true, "use hydrogen instruction canonicalizing")

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

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),
-        in_worklist_(graph->GetMaximumValueID(), zone()),
-        worklist_(32, zone()) {}
-
-  void Run();
-
- private:
-  void AddToWorklist(HValue* value) {
-    if (value->CheckFlag(HValue::kBailoutOnMinusZero)) return;
-    if (in_worklist_.Contains(value->id())) return;
-    in_worklist_.Add(value->id());
-    worklist_.Add(value, zone());
-  }
-  void PropagateMinusZeroChecks(HValue* value);
-
-  BitVector in_worklist_;
-  ZoneList<HValue*> worklist_;
-
-  DISALLOW_COPY_AND_ASSIGN(HComputeMinusZeroChecksPhase);
-};
-
-
-} }  // namespace v8::internal
-
-#endif  // V8_HYDROGEN_MINUS_ZERO_H_

src/hydrogen-range-analysis.cc

@@ -78,7 +78,29 @@ void HRangeAnalysisPhase::Run() {
 
     // Go through all instructions of the current block.
     for (HInstructionIterator it(block); !it.Done(); it.Advance()) {
-      InferRange(it.Current());
+      HValue* value = it.Current();
+      InferRange(value);
+
+      // Compute the bailout-on-minus-zero flag.
+      if (value->IsChange()) {
+        HChange* instr = HChange::cast(value);
+        // Propagate flags for negative zero checks upwards from conversions
+        // int32-to-tagged and int32-to-double.
+        Representation from = instr->value()->representation();
+        ASSERT(from.Equals(instr->from()));
+        if (from.IsSmiOrInteger32()) {
+          ASSERT(instr->to().IsTagged() ||
+                instr->to().IsDouble() ||
+                instr->to().IsSmiOrInteger32());
+          PropagateMinusZeroChecks(instr->value());
+        }
+      } else if (value->IsCompareMinusZeroAndBranch()) {
+        HCompareMinusZeroAndBranch* instr =
+            HCompareMinusZeroAndBranch::cast(value);
+        if (instr->value()->representation().IsSmiOrInteger32()) {
+          PropagateMinusZeroChecks(instr->value());
+        }
+      }
     }
 
     // Continue analysis in all dominated blocks.
@@ -197,4 +219,79 @@ void HRangeAnalysisPhase::AddRange(HValue* value, Range* range) {
 }
 
 
+void HRangeAnalysisPhase::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

src/hydrogen-range-analysis.h

@@ -37,7 +37,9 @@ namespace internal {
 class HRangeAnalysisPhase : public HPhase {
  public:
   explicit HRangeAnalysisPhase(HGraph* graph)
-      : HPhase("H_Range analysis", graph), changed_ranges_(16, zone()) { }
+      : HPhase("H_Range analysis", graph), changed_ranges_(16, zone()),
+        in_worklist_(graph->GetMaximumValueID(), zone()),
+        worklist_(32, zone()) {}
 
   void Run();
 
@@ -49,8 +51,19 @@ class HRangeAnalysisPhase : public HPhase {
   void InferRange(HValue* value);
   void RollBackTo(int index);
   void AddRange(HValue* value, Range* range);
+  void AddToWorklist(HValue* value) {
+    if (in_worklist_.Contains(value->id())) return;
+    in_worklist_.Add(value->id());
+    worklist_.Add(value, zone());
+  }
+  void PropagateMinusZeroChecks(HValue* value);
 
   ZoneList<HValue*> changed_ranges_;
+
+  BitVector in_worklist_;
+  ZoneList<HValue*> worklist_;
+
+  DISALLOW_COPY_AND_ASSIGN(HRangeAnalysisPhase);
 };
 
 

src/hydrogen.cc

@@ -48,7 +48,6 @@
 #include "hydrogen-gvn.h"
 #include "hydrogen-mark-deoptimize.h"
 #include "hydrogen-mark-unreachable.h"
-#include "hydrogen-minus-zero.h"
 #include "hydrogen-osr.h"
 #include "hydrogen-range-analysis.h"
 #include "hydrogen-redundant-phi.h"
@@ -4049,10 +4048,9 @@ bool HGraph::Optimize(BailoutReason* bailout_reason) {
 
   if (FLAG_check_elimination) Run<HCheckEliminationPhase>();
 
-  if (FLAG_use_range) Run<HRangeAnalysisPhase>();
+  Run<HRangeAnalysisPhase>();
 
   Run<HComputeChangeUndefinedToNaN>();
-  Run<HComputeMinusZeroChecksPhase>();
 
   // Eliminate redundant stack checks on backwards branches.
   Run<HStackCheckEliminationPhase>();

tools/gyp/v8.gyp

@@ -407,8 +407,6 @@
         '../../src/hydrogen-mark-deoptimize.h',
         '../../src/hydrogen-mark-unreachable.cc',
         '../../src/hydrogen-mark-unreachable.h',
-        '../../src/hydrogen-minus-zero.cc',
-        '../../src/hydrogen-minus-zero.h',
         '../../src/hydrogen-osr.cc',
         '../../src/hydrogen-osr.h',
         '../../src/hydrogen-range-analysis.cc',