Optimize the typeof operator.

src/arm/lithium-codegen-arm.cc

 // Copyright 2012 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/v8.h"
 
 #include "src/arm/lithium-codegen-arm.h"
 #include "src/arm/lithium-gap-resolver-arm.h"
 #include "src/base/bits.h"
 #include "src/code-factory.h"
@@ skipping 5532 matching lines @@
     __ mov(r2, Operand(instr->hydrogen()->shared_info()));
     __ mov(r1, Operand(pretenure ? factory()->true_value()
                                  : factory()->false_value()));
     __ Push(cp, r2, r1);
     CallRuntime(Runtime::kNewClosure, 3, instr);
   }
 }
 
 
 void LCodeGen::DoTypeof(LTypeof* instr) {
-  Register input = ToRegister(instr->value());
-  __ push(input);
-  CallRuntime(Runtime::kTypeof, 1, instr);
+  DCHECK(ToRegister(instr->value()).is(r3));
+  DCHECK(ToRegister(instr->result()).is(r0));
+  Label end, do_call;
+  Register value_register = ToRegister(instr->value());
+  __ JumpIfNotSmi(value_register, &do_call);
+  __ mov(r0, Operand(isolate()->factory()->number_string()));
+  __ jmp(&end);
+  __ bind(&do_call);
+  TypeofStub stub(isolate());
+  CallCode(stub.GetCode(), RelocInfo::CODE_TARGET, instr);
+  __ bind(&end);
 }
 
 
 void LCodeGen::DoTypeofIsAndBranch(LTypeofIsAndBranch* instr) {
   Register input = ToRegister(instr->value());
 
   Condition final_branch_condition = EmitTypeofIs(instr->TrueLabel(chunk_),
                                                   instr->FalseLabel(chunk_),
                                                   input,
                                                   instr->type_literal());
@@ skipping 377 matching lines @@
   __ Push(scope_info);
   __ push(ToRegister(instr->function()));
   CallRuntime(Runtime::kPushBlockContext, 2, instr);
   RecordSafepoint(Safepoint::kNoLazyDeopt);
 }
 
 
 #undef __
 
 } }  // namespace v8::internal