[turbofan] Introduce new Select operator to improve bounds checking.

src/compiler/common-operator.h

 // Copyright 2013 the V8 project authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 #ifndef V8_COMPILER_COMMON_OPERATOR_H_
 #define V8_COMPILER_COMMON_OPERATOR_H_
 
 #include "src/compiler/machine-type.h"
 #include "src/unique.h"
 
@@ skipping 15 matching lines @@
 // Prediction hint for branches.
 enum class BranchHint : uint8_t { kNone, kTrue, kFalse };
 
 inline size_t hash_value(BranchHint hint) { return static_cast<size_t>(hint); }
 
 std::ostream& operator<<(std::ostream&, BranchHint);
 
 BranchHint BranchHintOf(const Operator* const);
 
 
+class SelectParameters FINAL {
+ public:
+  explicit SelectParameters(MachineType type,
+                            BranchHint hint = BranchHint::kNone)
+      : type_(type), hint_(hint) {}
+
+  MachineType type() const { return type_; }
+  BranchHint hint() const { return hint_; }
+
+ private:
+  const MachineType type_;
+  const BranchHint hint_;
+};
+
+bool operator==(SelectParameters const&, SelectParameters const&);
+bool operator!=(SelectParameters const&, SelectParameters const&);
+
+size_t hash_value(SelectParameters const& p);
+
+std::ostream& operator<<(std::ostream&, SelectParameters const& p);
+
+SelectParameters const& SelectParametersOf(const Operator* const);
+
+
 // Flag that describes how to combine the current environment with
 // the output of a node to obtain a framestate for lazy bailout.
 class OutputFrameStateCombine {
  public:
   enum Kind {
     kPushOutput,  // Push the output on the expression stack.
     kPokeAt       // Poke at the given environment location,
                   // counting from the top of the stack.
   };
 
@@ skipping 104 matching lines @@
   const Operator* Parameter(int index);
 
   const Operator* Int32Constant(int32_t);
   const Operator* Int64Constant(int64_t);
   const Operator* Float32Constant(volatile float);
   const Operator* Float64Constant(volatile double);
   const Operator* ExternalConstant(const ExternalReference&);
   const Operator* NumberConstant(volatile double);
   const Operator* HeapConstant(const Unique<HeapObject>&);
 
+  const Operator* Select(MachineType, BranchHint = BranchHint::kNone);
   const Operator* Phi(MachineType type, int arguments);
   const Operator* EffectPhi(int arguments);
   const Operator* ValueEffect(int arguments);
   const Operator* Finish(int arguments);
   const Operator* StateValues(int arguments);
   const Operator* FrameState(
       FrameStateType type, BailoutId bailout_id,
       OutputFrameStateCombine state_combine,
       MaybeHandle<JSFunction> jsfunction = MaybeHandle<JSFunction>());
   const Operator* Call(const CallDescriptor* descriptor);
   const Operator* Projection(size_t index);
 
  private:
   Zone* zone() const { return zone_; }
 
   const CommonOperatorBuilderImpl& impl_;
   Zone* const zone_;
 
   DISALLOW_COPY_AND_ASSIGN(CommonOperatorBuilder);
 };
 
 }  // namespace compiler
 }  // namespace internal
 }  // namespace v8
 
 #endif  // V8_COMPILER_COMMON_OPERATOR_H_