Remove override mode from BinaryOpStub

src/code-stubs.h

Index: src/code-stubs.h
diff --git a/src/code-stubs.h b/src/code-stubs.h
index 30ec1c76ca9eda6e355032756c75758e0dfcee1d..5ea5ff10885eb47cf7a52c1ef3b544708c1fa2ec 100644
--- a/src/code-stubs.h
+++ b/src/code-stubs.h
@@ -122,9 +122,6 @@ namespace internal {
   CODE_STUB_LIST_ARM(V)              \
   CODE_STUB_LIST_MIPS(V)
 
-// Mode to overwrite BinaryExpression values.
-enum OverwriteMode { NO_OVERWRITE, OVERWRITE_LEFT, OVERWRITE_RIGHT };
-
 // Stub is base classes of all stubs.
 class CodeStub BASE_EMBEDDED {
  public:
@@ -978,9 +975,8 @@ class KeyedLoadFieldStub: public LoadFieldStub {
 
 class BinaryOpStub: public PlatformCodeStub {
  public:
-  BinaryOpStub(Token::Value op, OverwriteMode mode)
+  explicit BinaryOpStub(Token::Value op)
       : op_(op),
-        mode_(mode),
         platform_specific_bit_(false),
         left_type_(BinaryOpIC::UNINITIALIZED),
         right_type_(BinaryOpIC::UNINITIALIZED),
@@ -997,7 +993,6 @@ class BinaryOpStub: public PlatformCodeStub {
       BinaryOpIC::TypeInfo result_type,
       Maybe<int32_t> fixed_right_arg)
       : op_(OpBits::decode(key)),
-        mode_(ModeBits::decode(key)),
         platform_specific_bit_(PlatformSpecificBits::decode(key)),
         left_type_(left_type),
         right_type_(right_type),
@@ -1044,7 +1039,6 @@ class BinaryOpStub: public PlatformCodeStub {
 
  private:
   Token::Value op_;
-  OverwriteMode mode_;
   bool platform_specific_bit_;  // Indicates SSE3 on IA32.
 
   // Operand type information determined at runtime.
@@ -1068,7 +1062,6 @@ class BinaryOpStub: public PlatformCodeStub {
   // Minor key encoding in all 25 bits FFFFFHTTTRRRLLLPOOOOOOOMM.
   // Note: We actually do not need 7 bits for the operation, just 4 bits to
   // encode ADD, SUB, MUL, DIV, MOD, BIT_OR, BIT_AND, BIT_XOR, SAR, SHL, SHR.
-  class ModeBits: public BitField<OverwriteMode, 0, 2> {};
   class OpBits: public BitField<Token::Value, 2, 7> {};
   class PlatformSpecificBits: public BitField<bool, 9, 1> {};
   class LeftTypeBits: public BitField<BinaryOpIC::TypeInfo, 10, 3> {};
@@ -1080,7 +1073,6 @@ class BinaryOpStub: public PlatformCodeStub {
   Major MajorKey() { return BinaryOp; }
   int MinorKey() {
     return OpBits::encode(op_)
-           | ModeBits::encode(mode_)
            | PlatformSpecificBits::encode(platform_specific_bit_)
            | LeftTypeBits::encode(left_type_)
            | RightTypeBits::encode(right_type_)