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

src/compiler/opcodes.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_OPCODES_H_
 #define V8_COMPILER_OPCODES_H_
 
 // Opcodes for control operators.
 #define INNER_CONTROL_OP_LIST(V) \
   V(Dead)                        \
   V(Loop)                        \
   V(Branch)                      \
   V(IfTrue)                      \
   V(IfFalse)                     \
   V(Switch)                      \
-  V(Case)                        \
+  V(IfValue)                     \
+  V(IfDefault)                   \
   V(Merge)                       \
   V(Return)                      \
   V(OsrNormalEntry)              \
   V(OsrLoopEntry)                \
   V(Throw)
 
 #define CONTROL_OP_LIST(V) \
   INNER_CONTROL_OP_LIST(V) \
   V(Start)                 \
   V(End)
@@ skipping 274 matching lines @@
   static bool IsPhiOpcode(Value val) {
     return val == kPhi || val == kEffectPhi;
   }
 };
 
 }  // namespace compiler
 }  // namespace internal
 }  // namespace v8
 
 #endif  // V8_COMPILER_OPCODES_H_