[turbofan] Avoid unnecessary write barriers and improve code generation.

src/compiler/mips/instruction-codes-mips.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_MIPS_INSTRUCTION_CODES_MIPS_H_
 #define V8_COMPILER_MIPS_INSTRUCTION_CODES_MIPS_H_
 
 namespace v8 {
 namespace internal {
 namespace compiler {
@@ skipping 67 matching lines @@
   V(MipsFloat64ExtractLowWord32)   \
   V(MipsFloat64ExtractHighWord32)  \
   V(MipsFloat64InsertLowWord32)    \
   V(MipsFloat64InsertHighWord32)   \
   V(MipsFloat64Max)                \
   V(MipsFloat64Min)                \
   V(MipsFloat32Max)                \
   V(MipsFloat32Min)                \
   V(MipsPush)                      \
   V(MipsStoreToStackSlot)          \
-  V(MipsStackClaim)                \
-  V(MipsStoreWriteBarrier)
+  V(MipsStackClaim)
 
 
 // Addressing modes represent the "shape" of inputs to an instruction.
 // Many instructions support multiple addressing modes. Addressing modes
 // are encoded into the InstructionCode of the instruction and tell the
 // code generator after register allocation which assembler method to call.
 //
 // We use the following local notation for addressing modes:
 //
 // R = register
 // O = register or stack slot
 // D = double register
 // I = immediate (handle, external, int32)
 // MRI = [register + immediate]
 // MRR = [register + register]
 // TODO(plind): Add the new r6 address modes.
 #define TARGET_ADDRESSING_MODE_LIST(V) \
   V(MRI) /* [%r0 + K] */               \
   V(MRR) /* [%r0 + %r1] */
 
 
 }  // namespace compiler
 }  // namespace internal
 }  // namespace v8
 
 #endif  // V8_COMPILER_MIPS_INSTRUCTION_CODES_MIPS_H_