Remove the obsolete OverwriteMode optimization.

src/ia32/full-codegen-ia32.cc

Index: src/ia32/full-codegen-ia32.cc
diff --git a/src/ia32/full-codegen-ia32.cc b/src/ia32/full-codegen-ia32.cc
index 7a499151b50790c1606161cbedf9c6cc4f31a332..611a2c5c38eb0c59c6f5851b8f6a812316c5eab8 100644
--- a/src/ia32/full-codegen-ia32.cc
+++ b/src/ia32/full-codegen-ia32.cc
@@ -1964,18 +1964,14 @@ void FullCodeGenerator::VisitAssignment(Assignment* expr) {
     __ push(eax);  // Left operand goes on the stack.
     VisitForAccumulatorValue(expr->value());
 
-    OverwriteMode mode = expr->value()->ResultOverwriteAllowed()
-        ? OVERWRITE_RIGHT
-        : NO_OVERWRITE;
     SetSourcePosition(expr->position() + 1);
     if (ShouldInlineSmiCase(op)) {
       EmitInlineSmiBinaryOp(expr->binary_operation(),
                             op,
-                            mode,
                             expr->target(),
                             expr->value());
     } else {
-      EmitBinaryOp(expr->binary_operation(), op, mode);
+      EmitBinaryOp(expr->binary_operation(), op);
     }
 
     // Deoptimization point in case the binary operation may have side effects.
@@ -2356,7 +2352,6 @@ void FullCodeGenerator::EmitKeyedSuperPropertyLoad(Property* prop) {
 
 void FullCodeGenerator::EmitInlineSmiBinaryOp(BinaryOperation* expr,
                                               Token::Value op,
-                                              OverwriteMode mode,
                                               Expression* left,
                                               Expression* right) {
   // Do combined smi check of the operands. Left operand is on the
@@ -2370,7 +2365,7 @@ void FullCodeGenerator::EmitInlineSmiBinaryOp(BinaryOperation* expr,
 
   __ bind(&stub_call);
   __ mov(eax, ecx);
-  Handle<Code> code = CodeFactory::BinaryOpIC(isolate(), op, mode).code();
+  Handle<Code> code = CodeFactory::BinaryOpIC(isolate(), op).code();
   CallIC(code, expr->BinaryOperationFeedbackId());
   patch_site.EmitPatchInfo();
   __ jmp(&done, Label::kNear);
@@ -2502,11 +2497,9 @@ void FullCodeGenerator::EmitClassDefineProperties(ClassLiteral* lit) {
 }
 
 
-void FullCodeGenerator::EmitBinaryOp(BinaryOperation* expr,
-                                     Token::Value op,
-                                     OverwriteMode mode) {
+void FullCodeGenerator::EmitBinaryOp(BinaryOperation* expr, Token::Value op) {
   __ pop(edx);
-  Handle<Code> code = CodeFactory::BinaryOpIC(isolate(), op, mode).code();
+  Handle<Code> code = CodeFactory::BinaryOpIC(isolate(), op).code();
   JumpPatchSite patch_site(masm_);    // unbound, signals no inlined smi code.
   CallIC(code, expr->BinaryOperationFeedbackId());
   patch_site.EmitPatchInfo();
@@ -4778,8 +4771,8 @@ void FullCodeGenerator::VisitCountOperation(CountOperation* expr) {
   __ bind(&stub_call);
   __ mov(edx, eax);
   __ mov(eax, Immediate(Smi::FromInt(1)));
-  Handle<Code> code = CodeFactory::BinaryOpIC(isolate(), expr->binary_op(),
-                                              NO_OVERWRITE).code();
+  Handle<Code> code =
+      CodeFactory::BinaryOpIC(isolate(), expr->binary_op()).code();
   CallIC(code, expr->CountBinOpFeedbackId());
   patch_site.EmitPatchInfo();
   __ bind(&done);