[turbofan] Optimize certain chains of Branch into a Switch.

src/compiler/operator-properties.cc

 // 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.
 
 #include "src/compiler/operator-properties.h"
 
 #include "src/compiler/js-operator.h"
 #include "src/compiler/linkage.h"
 #include "src/compiler/opcodes.h"
 
@@ skipping 82 matching lines @@
          op->ControlInputCount();
 }
 
 
 // static
 bool OperatorProperties::IsBasicBlockBegin(const Operator* op) {
   Operator::Opcode const opcode = op->opcode();
   return opcode == IrOpcode::kStart || opcode == IrOpcode::kEnd ||
          opcode == IrOpcode::kDead || opcode == IrOpcode::kLoop ||
          opcode == IrOpcode::kMerge || opcode == IrOpcode::kIfTrue ||
-         opcode == IrOpcode::kIfFalse;
+         opcode == IrOpcode::kIfFalse || opcode == IrOpcode::kIfValue ||
+         opcode == IrOpcode::kIfDefault;
 }
 
 }  // namespace compiler
 }  // namespace internal
 }  // namespace v8