[turbofan] Ensure that NTLs are always properly connected to the end.

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 144 matching lines @@
 
 size_t ProjectionIndexOf(const Operator* const);
 
 
 // Interface for building common operators that can be used at any level of IR,
 // including JavaScript, mid-level, and low-level.
 class CommonOperatorBuilder FINAL : public ZoneObject {
  public:
   explicit CommonOperatorBuilder(Zone* zone);
 
+  // Special operator used only in Branches to mark them as always taken, but
+  // still unfoldable. This is required to properly connect non terminating
+  // loops to end (in both the sea of nodes and the CFG).
+  const Operator* Always();
+
   const Operator* Dead();
   const Operator* End();
   const Operator* Branch(BranchHint = BranchHint::kNone);
   const Operator* IfTrue();
   const Operator* IfFalse();
   const Operator* Throw();
-  const Operator* Terminate(int effects);
   const Operator* Return();
 
   const Operator* Start(int num_formal_parameters);
   const Operator* Loop(int control_input_count);
   const Operator* Merge(int control_input_count);
   const Operator* Parameter(int index);
 
   const Operator* OsrNormalEntry();
   const Operator* OsrLoopEntry();
   const Operator* OsrValue(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* EffectSet(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);
 
   // Constructs a new merge or phi operator with the same opcode as {op}, but
   // with {size} inputs.
   const Operator* ResizeMergeOrPhi(const Operator* op, int size);
 
  private:
   Zone* zone() const { return zone_; }
 
   const CommonOperatorGlobalCache& cache_;
   Zone* const zone_;
 
   DISALLOW_COPY_AND_ASSIGN(CommonOperatorBuilder);
 };
 
 }  // namespace compiler
 }  // namespace internal
 }  // namespace v8
 
 #endif  // V8_COMPILER_COMMON_OPERATOR_H_