[turbofan] Introduce explicit loop exits markers.

src/compiler/common-operator.h

 // Copyright 2014 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/assembler.h"
 #include "src/compiler/frame-states.h"
 #include "src/machine-type.h"
@@ skipping 184 matching lines @@
 
   const Operator* RelocatableInt32Constant(int32_t value,
                                            RelocInfo::Mode rmode);
   const Operator* RelocatableInt64Constant(int64_t value,
                                            RelocInfo::Mode rmode);
 
   const Operator* Select(MachineRepresentation, BranchHint = BranchHint::kNone);
   const Operator* Phi(MachineRepresentation representation,
                       int value_input_count);
   const Operator* EffectPhi(int effect_input_count);
+  const Operator* LoopExit();
+  const Operator* LoopExitValue();
+  const Operator* LoopExitEffect();
   const Operator* Checkpoint();
   const Operator* BeginRegion(RegionObservability);
   const Operator* FinishRegion();
   const Operator* StateValues(int arguments);
   const Operator* ObjectState(int pointer_slots, int id);
   const Operator* TypedStateValues(const ZoneVector<MachineType>* types);
   const Operator* FrameState(BailoutId bailout_id,
                              OutputFrameStateCombine state_combine,
                              const FrameStateFunctionInfo* function_info);
   const Operator* Call(const CallDescriptor* descriptor);
@@ skipping 16 matching lines @@
   Zone* const zone_;
 
   DISALLOW_COPY_AND_ASSIGN(CommonOperatorBuilder);
 };
 
 }  // namespace compiler
 }  // namespace internal
 }  // namespace v8
 
 #endif  // V8_COMPILER_COMMON_OPERATOR_H_