Optimize the typeof operator.

src/mips/full-codegen-mips.cc

Index: src/mips/full-codegen-mips.cc
diff --git a/src/mips/full-codegen-mips.cc b/src/mips/full-codegen-mips.cc
index 0756b092f39f27359e7a441219651c165f5ecb5f..5ac885a93cf92e637c05bf9814752640b61289d5 100644
--- a/src/mips/full-codegen-mips.cc
+++ b/src/mips/full-codegen-mips.cc
@@ -4802,10 +4802,13 @@ void FullCodeGenerator::VisitUnaryOperation(UnaryOperation* expr) {
 
     case Token::TYPEOF: {
       Comment cmnt(masm_, "[ UnaryOperation (TYPEOF)");
-      { StackValueContext context(this);
+      {
+        AccumulatorValueContext context(this);
         VisitForTypeofValue(expr->expression());
       }
-      __ CallRuntime(Runtime::kTypeof, 1);
+      __ mov(a3, v0);
+      TypeofStub typeof_stub(isolate());
+      __ CallStub(&typeof_stub);
       context()->Plug(v0);
       break;
     }