[turbofan] Connect non-terminating loops via Terminate.

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 165 matching lines @@
 int ParameterIndexOf(const Operator* const);
 const ParameterInfo& ParameterInfoOf(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* IfSuccess();
   const Operator* IfException();
   const Operator* Switch(size_t control_output_count);
   const Operator* IfValue(int32_t value);
   const Operator* IfDefault();
   const Operator* Throw();
   const Operator* Deoptimize();
   const Operator* Return();
+  const Operator* Terminate();
 
   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 char* debug_name = nullptr);
 
   const Operator* OsrNormalEntry();
   const Operator* OsrLoopEntry();
   const Operator* OsrValue(int index);
 
@@ skipping 32 matching lines @@
   Zone* const zone_;
 
   DISALLOW_COPY_AND_ASSIGN(CommonOperatorBuilder);
 };
 
 }  // namespace compiler
 }  // namespace internal
 }  // namespace v8
 
 #endif  // V8_COMPILER_COMMON_OPERATOR_H_