Merge "Opt compiler: Basic simplification for arithmetic operations."

4 files changed, 526 insertions, 0 deletions

diff --git a/compiler/optimizing/constant_folding.cc b/compiler/optimizing/constant_folding.cc
index fca9933872..ec0cc3e98b 100644
--- a/compiler/optimizing/constant_folding.cc
+++ b/compiler/optimizing/constant_folding.cc
@@ -18,7 +18,28 @@
 
 namespace art {
 
+// This visitor tries to simplify operations that yield a constant. For example
+// `input * 0` is replaced by a null constant.
+class InstructionWithAbsorbingInputSimplifier : public HGraphVisitor {
+ public:
+  explicit InstructionWithAbsorbingInputSimplifier(HGraph* graph) : HGraphVisitor(graph) {}
+
+ private:
+  void VisitShift(HBinaryOperation* shift);
+
+  void VisitAnd(HAnd* instruction) OVERRIDE;
+  void VisitMul(HMul* instruction) OVERRIDE;
+  void VisitOr(HOr* instruction) OVERRIDE;
+  void VisitRem(HRem* instruction) OVERRIDE;
+  void VisitShl(HShl* instruction) OVERRIDE;
+  void VisitShr(HShr* instruction) OVERRIDE;
+  void VisitSub(HSub* instruction) OVERRIDE;
+  void VisitUShr(HUShr* instruction) OVERRIDE;
+  void VisitXor(HXor* instruction) OVERRIDE;
+};
+
 void HConstantFolding::Run() {
+  InstructionWithAbsorbingInputSimplifier simplifier(graph_);
   // Process basic blocks in reverse post-order in the dominator tree,
   // so that an instruction turned into a constant, used as input of
   // another instruction, may possibly be used to turn that second
@@ -38,6 +59,8 @@ void HConstantFolding::Run() {
             inst->AsBinaryOperation()->TryStaticEvaluation();
         if (constant != nullptr) {
           inst->GetBlock()->ReplaceAndRemoveInstructionWith(inst, constant);
+        } else {
+          inst->Accept(&simplifier);
         }
       } else if (inst->IsUnaryOperation()) {
         // Constant folding: replace `op(a)' with a constant at compile
@@ -47,9 +70,166 @@ void HConstantFolding::Run() {
         if (constant != nullptr) {
           inst->GetBlock()->ReplaceAndRemoveInstructionWith(inst, constant);
         }
+      } else if (inst->IsDivZeroCheck()) {
+        // We can safely remove the check if the input is a non-null constant.
+        HDivZeroCheck* check = inst->AsDivZeroCheck();
+        HInstruction* check_input = check->InputAt(0);
+        if (check_input->IsConstant() && !check_input->AsConstant()->IsZero()) {
+          check->ReplaceWith(check_input);
+          check->GetBlock()->RemoveInstruction(check);
+        }
       }
     }
   }
 }
 
+void InstructionWithAbsorbingInputSimplifier::VisitShift(HBinaryOperation* instruction) {
+  DCHECK(instruction->IsShl() || instruction->IsShr() || instruction->IsUShr());
+  HInstruction* left = instruction->GetLeft();
+  if (left->IsConstant() && left->AsConstant()->IsZero()) {
+    // Replace code looking like
+    //    SHL dst, 0, shift_amount
+    // with
+    //    CONSTANT 0
+    instruction->ReplaceWith(left);
+    instruction->GetBlock()->RemoveInstruction(instruction);
+  }
+}
+
+void InstructionWithAbsorbingInputSimplifier::VisitAnd(HAnd* instruction) {
+  HConstant* input_cst = instruction->GetConstantRight();
+  if ((input_cst != nullptr) && input_cst->IsZero()) {
+    // Replace code looking like
+    //    AND dst, src, 0
+    // with
+    //    CONSTANT 0
+    instruction->ReplaceWith(input_cst);
+    instruction->GetBlock()->RemoveInstruction(instruction);
+  }
+}
+
+void InstructionWithAbsorbingInputSimplifier::VisitMul(HMul* instruction) {
+  HConstant* input_cst = instruction->GetConstantRight();
+  Primitive::Type type = instruction->GetType();
+  if (Primitive::IsIntOrLongType(type) &&
+      (input_cst != nullptr) && input_cst->IsZero()) {
+    // Replace code looking like
+    //    MUL dst, src, 0
+    // with
+    //    CONSTANT 0
+    // Integral multiplication by zero always yields zero, but floating-point
+    // multiplication by zero does not always do. For example `Infinity * 0.0`
+    // should yield a NaN.
+    instruction->ReplaceWith(input_cst);
+    instruction->GetBlock()->RemoveInstruction(instruction);
+  }
+}
+
+void InstructionWithAbsorbingInputSimplifier::VisitOr(HOr* instruction) {
+  HConstant* input_cst = instruction->GetConstantRight();
+
+  if (input_cst == nullptr) {
+    return;
+  }
+
+  if (Int64FromConstant(input_cst) == -1) {
+    // Replace code looking like
+    //    OR dst, src, 0xFFF...FF
+    // with
+    //    CONSTANT 0xFFF...FF
+    instruction->ReplaceWith(input_cst);
+    instruction->GetBlock()->RemoveInstruction(instruction);
+  }
+}
+
+void InstructionWithAbsorbingInputSimplifier::VisitRem(HRem* instruction) {
+  Primitive::Type type = instruction->GetType();
+
+  if (!Primitive::IsIntegralType(type)) {
+    return;
+  }
+
+  HBasicBlock* block = instruction->GetBlock();
+
+  if (instruction->GetLeft()->IsConstant() &&
+      instruction->GetLeft()->AsConstant()->IsZero()) {
+    // Replace code looking like
+    //    REM dst, 0, src
+    // with
+    //    CONSTANT 0
+    instruction->ReplaceWith(instruction->GetLeft());
+    block->RemoveInstruction(instruction);
+  }
+
+  HConstant* cst_right = instruction->GetRight()->AsConstant();
+  if (((cst_right != nullptr) &&
+       (cst_right->IsOne() || cst_right->IsMinusOne())) ||
+      (instruction->GetLeft() == instruction->GetRight())) {
+    // Replace code looking like
+    //    REM dst, src, 1
+    // or
+    //    REM dst, src, -1
+    // or
+    //    REM dst, src, src
+    // with
+    //    CONSTANT 0
+    ArenaAllocator* allocator = GetGraph()->GetArena();
+    block->ReplaceAndRemoveInstructionWith(instruction,
+                                           HConstant::NewConstant(allocator, type, 0));
+  }
+}
+
+void InstructionWithAbsorbingInputSimplifier::VisitShl(HShl* instruction) {
+  VisitShift(instruction);
+}
+
+void InstructionWithAbsorbingInputSimplifier::VisitShr(HShr* instruction) {
+  VisitShift(instruction);
+}
+
+void InstructionWithAbsorbingInputSimplifier::VisitSub(HSub* instruction) {
+  Primitive::Type type = instruction->GetType();
+
+  if (!Primitive::IsIntegralType(type)) {
+    return;
+  }
+
+  HBasicBlock* block = instruction->GetBlock();
+  ArenaAllocator* allocator = GetGraph()->GetArena();
+
+  // We assume that GVN has run before, so we only perform a pointer
+  // comparison.  If for some reason the values are equal but the pointers are
+  // different, we are still correct and only miss an optimisation
+  // opportunity.
+  if (instruction->GetLeft() == instruction->GetRight()) {
+    // Replace code looking like
+    //    SUB dst, src, src
+    // with
+    //    CONSTANT 0
+    // Note that we cannot optimise `x - x` to `0` for floating-point. It does
+    // not work when `x` is an infinity.
+    block->ReplaceAndRemoveInstructionWith(instruction,
+                                           HConstant::NewConstant(allocator, type, 0));
+  }
+}
+
+void InstructionWithAbsorbingInputSimplifier::VisitUShr(HUShr* instruction) {
+  VisitShift(instruction);
+}
+
+void InstructionWithAbsorbingInputSimplifier::VisitXor(HXor* instruction) {
+  if (instruction->GetLeft() == instruction->GetRight()) {
+    // Replace code looking like
+    //    XOR dst, src, src
+    // with
+    //    CONSTANT 0
+    Primitive::Type type = instruction->GetType();
+    HBasicBlock* block = instruction->GetBlock();
+    ArenaAllocator* allocator = GetGraph()->GetArena();
+
+    block->ReplaceAndRemoveInstructionWith(instruction,
+                                           HConstant::NewConstant(allocator, type, 0));
+  }
+}
+
 }  // namespace art
diff --git a/compiler/optimizing/instruction_simplifier.cc b/compiler/optimizing/instruction_simplifier.cc
index fd99070780..2ef19b92a1 100644
--- a/compiler/optimizing/instruction_simplifier.cc
+++ b/compiler/optimizing/instruction_simplifier.cc
@@ -27,6 +27,8 @@ class InstructionSimplifierVisitor : public HGraphVisitor {
       : HGraphVisitor(graph), stats_(stats) {}
 
  private:
+  void VisitShift(HBinaryOperation* shift);
+
   void VisitSuspendCheck(HSuspendCheck* check) OVERRIDE;
   void VisitEqual(HEqual* equal) OVERRIDE;
   void VisitArraySet(HArraySet* equal) OVERRIDE;
@@ -34,6 +36,16 @@ class InstructionSimplifierVisitor : public HGraphVisitor {
   void VisitNullCheck(HNullCheck* instruction) OVERRIDE;
   void VisitArrayLength(HArrayLength* instruction) OVERRIDE;
   void VisitCheckCast(HCheckCast* instruction) OVERRIDE;
+  void VisitAdd(HAdd* instruction) OVERRIDE;
+  void VisitAnd(HAnd* instruction) OVERRIDE;
+  void VisitDiv(HDiv* instruction) OVERRIDE;
+  void VisitMul(HMul* instruction) OVERRIDE;
+  void VisitOr(HOr* instruction) OVERRIDE;
+  void VisitShl(HShl* instruction) OVERRIDE;
+  void VisitShr(HShr* instruction) OVERRIDE;
+  void VisitSub(HSub* instruction) OVERRIDE;
+  void VisitUShr(HUShr* instruction) OVERRIDE;
+  void VisitXor(HXor* instruction) OVERRIDE;
 
   OptimizingCompilerStats* stats_;
 };
@@ -43,6 +55,29 @@ void InstructionSimplifier::Run() {
   visitor.VisitInsertionOrder();
 }
 
+namespace {
+
+bool AreAllBitsSet(HConstant* constant) {
+  return Int64FromConstant(constant) == -1;
+}
+
+}  // namespace
+
+void InstructionSimplifierVisitor::VisitShift(HBinaryOperation* instruction) {
+  DCHECK(instruction->IsShl() || instruction->IsShr() || instruction->IsUShr());
+  HConstant* input_cst = instruction->GetConstantRight();
+  HInstruction* input_other = instruction->GetLeastConstantLeft();
+
+  if ((input_cst != nullptr) && input_cst->IsZero()) {
+    // Replace code looking like
+    //    SHL dst, src, 0
+    // with
+    //    src
+    instruction->ReplaceWith(input_other);
+    instruction->GetBlock()->RemoveInstruction(instruction);
+  }
+}
+
 void InstructionSimplifierVisitor::VisitNullCheck(HNullCheck* null_check) {
   HInstruction* obj = null_check->InputAt(0);
   if (!obj->CanBeNull()) {
@@ -137,4 +172,234 @@ void InstructionSimplifierVisitor::VisitTypeConversion(HTypeConversion* instruct
   }
 }
 
+void InstructionSimplifierVisitor::VisitAdd(HAdd* instruction) {
+  HConstant* input_cst = instruction->GetConstantRight();
+  HInstruction* input_other = instruction->GetLeastConstantLeft();
+  if ((input_cst != nullptr) && input_cst->IsZero()) {
+    // Replace code looking like
+    //    ADD dst, src, 0
+    // with
+    //    src
+    instruction->ReplaceWith(input_other);
+    instruction->GetBlock()->RemoveInstruction(instruction);
+  }
+}
+
+void InstructionSimplifierVisitor::VisitAnd(HAnd* instruction) {
+  HConstant* input_cst = instruction->GetConstantRight();
+  HInstruction* input_other = instruction->GetLeastConstantLeft();
+
+  if ((input_cst != nullptr) && AreAllBitsSet(input_cst)) {
+    // Replace code looking like
+    //    AND dst, src, 0xFFF...FF
+    // with
+    //    src
+    instruction->ReplaceWith(input_other);
+    instruction->GetBlock()->RemoveInstruction(instruction);
+    return;
+  }
+
+  // We assume that GVN has run before, so we only perform a pointer comparison.
+  // If for some reason the values are equal but the pointers are different, we
+  // are still correct and only miss an optimisation opportunity.
+  if (instruction->GetLeft() == instruction->GetRight()) {
+    // Replace code looking like
+    //    AND dst, src, src
+    // with
+    //    src
+    instruction->ReplaceWith(instruction->GetLeft());
+    instruction->GetBlock()->RemoveInstruction(instruction);
+  }
+}
+
+void InstructionSimplifierVisitor::VisitDiv(HDiv* instruction) {
+  HConstant* input_cst = instruction->GetConstantRight();
+  HInstruction* input_other = instruction->GetLeastConstantLeft();
+  Primitive::Type type = instruction->GetType();
+
+  if ((input_cst != nullptr) && input_cst->IsOne()) {
+    // Replace code looking like
+    //    DIV dst, src, 1
+    // with
+    //    src
+    instruction->ReplaceWith(input_other);
+    instruction->GetBlock()->RemoveInstruction(instruction);
+    return;
+  }
+
+  if ((input_cst != nullptr) && input_cst->IsMinusOne() &&
+      (Primitive::IsFloatingPointType(type) || Primitive::IsIntOrLongType(type))) {
+    // Replace code looking like
+    //    DIV dst, src, -1
+    // with
+    //    NEG dst, src
+    instruction->GetBlock()->ReplaceAndRemoveInstructionWith(
+        instruction, (new (GetGraph()->GetArena()) HNeg(type, input_other)));
+  }
+}
+
+void InstructionSimplifierVisitor::VisitMul(HMul* instruction) {
+  HConstant* input_cst = instruction->GetConstantRight();
+  HInstruction* input_other = instruction->GetLeastConstantLeft();
+  Primitive::Type type = instruction->GetType();
+  HBasicBlock* block = instruction->GetBlock();
+  ArenaAllocator* allocator = GetGraph()->GetArena();
+
+  if (input_cst == nullptr) {
+    return;
+  }
+
+  if (input_cst->IsOne()) {
+    // Replace code looking like
+    //    MUL dst, src, 1
+    // with
+    //    src
+    instruction->ReplaceWith(input_other);
+    instruction->GetBlock()->RemoveInstruction(instruction);
+    return;
+  }
+
+  if (input_cst->IsMinusOne() &&
+      (Primitive::IsFloatingPointType(type) || Primitive::IsIntOrLongType(type))) {
+    // Replace code looking like
+    //    MUL dst, src, -1
+    // with
+    //    NEG dst, src
+    HNeg* neg = new (allocator) HNeg(type, input_other);
+    block->ReplaceAndRemoveInstructionWith(instruction, neg);
+    return;
+  }
+
+  if (Primitive::IsFloatingPointType(type) &&
+      ((input_cst->IsFloatConstant() && input_cst->AsFloatConstant()->GetValue() == 2.0f) ||
+       (input_cst->IsDoubleConstant() && input_cst->AsDoubleConstant()->GetValue() == 2.0))) {
+    // Replace code looking like
+    //    FP_MUL dst, src, 2.0
+    // with
+    //    FP_ADD dst, src, src
+    // The 'int' and 'long' cases are handled below.
+    block->ReplaceAndRemoveInstructionWith(instruction,
+                                           new (allocator) HAdd(type, input_other, input_other));
+    return;
+  }
+
+  if (Primitive::IsIntOrLongType(type)) {
+    int64_t factor = Int64FromConstant(input_cst);
+    // We expect the `0` case to have been handled in the constant folding pass.
+    DCHECK_NE(factor, 0);
+    if (IsPowerOfTwo(factor)) {
+      // Replace code looking like
+      //    MUL dst, src, pow_of_2
+      // with
+      //    SHL dst, src, log2(pow_of_2)
+      HIntConstant* shift = new (allocator) HIntConstant(WhichPowerOf2(factor));
+      block->InsertInstructionBefore(shift, instruction);
+      HShl* shl = new(allocator) HShl(type, input_other, shift);
+      block->ReplaceAndRemoveInstructionWith(instruction, shl);
+    }
+  }
+}
+
+void InstructionSimplifierVisitor::VisitOr(HOr* instruction) {
+  HConstant* input_cst = instruction->GetConstantRight();
+  HInstruction* input_other = instruction->GetLeastConstantLeft();
+
+  if ((input_cst != nullptr) && input_cst->IsZero()) {
+    // Replace code looking like
+    //    OR dst, src, 0
+    // with
+    //    src
+    instruction->ReplaceWith(input_other);
+    instruction->GetBlock()->RemoveInstruction(instruction);
+    return;
+  }
+
+  // We assume that GVN has run before, so we only perform a pointer comparison.
+  // If for some reason the values are equal but the pointers are different, we
+  // are still correct and only miss an optimisation opportunity.
+  if (instruction->GetLeft() == instruction->GetRight()) {
+    // Replace code looking like
+    //    OR dst, src, src
+    // with
+    //    src
+    instruction->ReplaceWith(instruction->GetLeft());
+    instruction->GetBlock()->RemoveInstruction(instruction);
+  }
+}
+
+void InstructionSimplifierVisitor::VisitShl(HShl* instruction) {
+  VisitShift(instruction);
+}
+
+void InstructionSimplifierVisitor::VisitShr(HShr* instruction) {
+  VisitShift(instruction);
+}
+
+void InstructionSimplifierVisitor::VisitSub(HSub* instruction) {
+  HConstant* input_cst = instruction->GetConstantRight();
+  HInstruction* input_other = instruction->GetLeastConstantLeft();
+
+  if ((input_cst != nullptr) && input_cst->IsZero()) {
+    // Replace code looking like
+    //    SUB dst, src, 0
+    // with
+    //    src
+    instruction->ReplaceWith(input_other);
+    instruction->GetBlock()->RemoveInstruction(instruction);
+    return;
+  }
+
+  Primitive::Type type = instruction->GetType();
+  if (!Primitive::IsIntegralType(type)) {
+    return;
+  }
+
+  HBasicBlock* block = instruction->GetBlock();
+  ArenaAllocator* allocator = GetGraph()->GetArena();
+
+  if (instruction->GetLeft()->IsConstant()) {
+    int64_t left = Int64FromConstant(instruction->GetLeft()->AsConstant());
+    if (left == 0) {
+      // Replace code looking like
+      //    SUB dst, 0, src
+      // with
+      //    NEG dst, src
+      // Note that we cannot optimise `0.0 - x` to `-x` for floating-point. When
+      // `x` is `0.0`, the former expression yields `0.0`, while the later
+      // yields `-0.0`.
+      HNeg* neg = new (allocator) HNeg(type, instruction->GetRight());
+      block->ReplaceAndRemoveInstructionWith(instruction, neg);
+    }
+  }
+}
+
+void InstructionSimplifierVisitor::VisitUShr(HUShr* instruction) {
+  VisitShift(instruction);
+}
+
+void InstructionSimplifierVisitor::VisitXor(HXor* instruction) {
+  HConstant* input_cst = instruction->GetConstantRight();
+  HInstruction* input_other = instruction->GetLeastConstantLeft();
+
+  if ((input_cst != nullptr) && input_cst->IsZero()) {
+    // Replace code looking like
+    //    XOR dst, src, 0
+    // with
+    //    src
+    instruction->ReplaceWith(input_other);
+    instruction->GetBlock()->RemoveInstruction(instruction);
+    return;
+  }
+
+  if ((input_cst != nullptr) && AreAllBitsSet(input_cst)) {
+    // Replace code looking like
+    //    XOR dst, src, 0xFFF...FF
+    // with
+    //    NOT dst, src
+    HNot* bitwise_not = new (GetGraph()->GetArena()) HNot(instruction->GetType(), input_other);
+    instruction->GetBlock()->ReplaceAndRemoveInstructionWith(instruction, bitwise_not);
+    return;
+  }
+}
+
 }  // namespace art
diff --git a/compiler/optimizing/nodes.cc b/compiler/optimizing/nodes.cc
index a6adcca490..a90ebced69 100644
--- a/compiler/optimizing/nodes.cc
+++ b/compiler/optimizing/nodes.cc
@@ -673,10 +673,43 @@ HConstant* HBinaryOperation::TryStaticEvaluation() const {
   return nullptr;
 }
 
+HConstant* HBinaryOperation::GetConstantRight() const {
+  if (GetRight()->IsConstant()) {
+    return GetRight()->AsConstant();
+  } else if (IsCommutative() && GetLeft()->IsConstant()) {
+    return GetLeft()->AsConstant();
+  } else {
+    return nullptr;
+  }
+}
+
+// If `GetConstantRight()` returns one of the input, this returns the other
+// one. Otherwise it returns nullptr.
+HInstruction* HBinaryOperation::GetLeastConstantLeft() const {
+  HInstruction* most_constant_right = GetConstantRight();
+  if (most_constant_right == nullptr) {
+    return nullptr;
+  } else if (most_constant_right == GetLeft()) {
+    return GetRight();
+  } else {
+    return GetLeft();
+  }
+}
+
 bool HCondition::IsBeforeWhenDisregardMoves(HIf* if_) const {
   return this == if_->GetPreviousDisregardingMoves();
 }
 
+HConstant* HConstant::NewConstant(ArenaAllocator* allocator, Primitive::Type type, int64_t val) {
+  if (type == Primitive::kPrimInt) {
+    DCHECK(IsInt<32>(val));
+    return new (allocator) HIntConstant(val);
+  } else {
+    DCHECK_EQ(type, Primitive::kPrimLong);
+    return new (allocator) HLongConstant(val);
+  }
+}
+
 bool HInstruction::Equals(HInstruction* other) const {
   if (!InstructionTypeEquals(other)) return false;
   DCHECK_EQ(GetKind(), other->GetKind());
diff --git a/compiler/optimizing/nodes.h b/compiler/optimizing/nodes.h
index 0ef174dcd5..ec3d7438ab 100644
--- a/compiler/optimizing/nodes.h
+++ b/compiler/optimizing/nodes.h
@@ -1574,6 +1574,14 @@ class HBinaryOperation : public HExpression<2> {
   virtual int32_t Evaluate(int32_t x, int32_t y) const = 0;
   virtual int64_t Evaluate(int64_t x, int64_t y) const = 0;
 
+  // Returns an input that can legally be used as the right input and is
+  // constant, or nullptr.
+  HConstant* GetConstantRight() const;
+
+  // If `GetConstantRight()` returns one of the input, this returns the other
+  // one. Otherwise it returns nullptr.
+  HInstruction* GetLeastConstantLeft() const;
+
   DECLARE_INSTRUCTION(BinaryOperation);
 
  private:
@@ -1845,6 +1853,12 @@ class HConstant : public HExpression<0> {
 
   bool CanBeMoved() const OVERRIDE { return true; }
 
+  virtual bool IsMinusOne() const { return false; }
+  virtual bool IsZero() const { return false; }
+  virtual bool IsOne() const { return false; }
+
+  static HConstant* NewConstant(ArenaAllocator* allocator, Primitive::Type type, int64_t val);
+
   DECLARE_INSTRUCTION(Constant);
 
  private:
@@ -1864,6 +1878,16 @@ class HFloatConstant : public HConstant {
 
   size_t ComputeHashCode() const OVERRIDE { return static_cast<size_t>(GetValue()); }
 
+  bool IsMinusOne() const OVERRIDE {
+    return bit_cast<uint32_t>(AsFloatConstant()->GetValue()) == bit_cast<uint32_t>((-1.0f));
+  }
+  bool IsZero() const OVERRIDE {
+    return AsFloatConstant()->GetValue() == 0.0f;
+  }
+  bool IsOne() const OVERRIDE {
+    return bit_cast<uint32_t>(AsFloatConstant()->GetValue()) == bit_cast<uint32_t>(1.0f);
+  }
+
   DECLARE_INSTRUCTION(FloatConstant);
 
  private:
@@ -1885,6 +1909,16 @@ class HDoubleConstant : public HConstant {
 
   size_t ComputeHashCode() const OVERRIDE { return static_cast<size_t>(GetValue()); }
 
+  bool IsMinusOne() const OVERRIDE {
+    return bit_cast<uint64_t>(AsDoubleConstant()->GetValue()) == bit_cast<uint64_t>((-1.0));
+  }
+  bool IsZero() const OVERRIDE {
+    return AsDoubleConstant()->GetValue() == 0.0;
+  }
+  bool IsOne() const OVERRIDE {
+    return bit_cast<uint64_t>(AsDoubleConstant()->GetValue()) == bit_cast<uint64_t>(1.0);
+  }
+
   DECLARE_INSTRUCTION(DoubleConstant);
 
  private:
@@ -1930,6 +1964,10 @@ class HIntConstant : public HConstant {
   // method is an workaround until we fix the above.
   bool ActAsNullConstant() const OVERRIDE { return value_ == 0; }
 
+  bool IsMinusOne() const OVERRIDE { return GetValue() == -1; }
+  bool IsZero() const OVERRIDE { return GetValue() == 0; }
+  bool IsOne() const OVERRIDE { return GetValue() == 1; }
+
   DECLARE_INSTRUCTION(IntConstant);
 
  private:
@@ -1950,6 +1988,10 @@ class HLongConstant : public HConstant {
 
   size_t ComputeHashCode() const OVERRIDE { return static_cast<size_t>(GetValue()); }
 
+  bool IsMinusOne() const OVERRIDE { return GetValue() == -1; }
+  bool IsZero() const OVERRIDE { return GetValue() == 0; }
+  bool IsOne() const OVERRIDE { return GetValue() == 1; }
+
   DECLARE_INSTRUCTION(LongConstant);
 
  private:
@@ -3478,6 +3520,12 @@ class HBlocksInLoopIterator : public ValueObject {
   DISALLOW_COPY_AND_ASSIGN(HBlocksInLoopIterator);
 };
 
+inline int64_t Int64FromConstant(HConstant* constant) {
+  DCHECK(constant->IsIntConstant() || constant->IsLongConstant());
+  return constant->IsIntConstant() ? constant->AsIntConstant()->GetValue()
+                                   : constant->AsLongConstant()->GetValue();
+}
+
 }  // namespace art
 
 #endif  // ART_COMPILER_OPTIMIZING_NODES_H_