Optimize the typeof operator.

src/mips64/lithium-codegen-mips64.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/code-factory.h"
 #include "src/code-stubs.h"
 #include "src/cpu-profiler.h"
 #include "src/hydrogen-osr.h"
@@ skipping 5597 matching lines @@
     __ li(a2, Operand(instr->hydrogen()->shared_info()));
     __ li(a1, Operand(pretenure ? factory()->true_value()
                                 : factory()->false_value()));
     __ Push(cp, a2, a1);
     CallRuntime(Runtime::kNewClosure, 3, instr);
   }
 }
 
 
 void LCodeGen::DoTypeof(LTypeof* instr) {
+  DCHECK(ToRegister(instr->value()).is(a3));
   DCHECK(ToRegister(instr->result()).is(v0));
-  Register input = ToRegister(instr->value());
-  __ push(input);
-  CallRuntime(Runtime::kTypeof, 1, instr);
+  Label end, do_call;
+  Register value_register = ToRegister(instr->value());
+  __ JumpIfNotSmi(value_register, &do_call);
+  __ li(v0, 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());
 
   Register cmp1 = no_reg;
   Operand cmp2 = Operand(no_reg);
 
   Condition final_branch_condition = EmitTypeofIs(instr->TrueLabel(chunk_),
@@ skipping 410 matching lines @@
   __ li(at, scope_info);
   __ Push(at, ToRegister(instr->function()));
   CallRuntime(Runtime::kPushBlockContext, 2, instr);
   RecordSafepoint(Safepoint::kNoLazyDeopt);
 }
 
 
 #undef __
 
 } }  // namespace v8::internal