Optimize the typeof operator.

src/arm64/lithium-arm64.cc

 // Copyright 2013 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 <sstream>
 
 #include "src/v8.h"
 
 #include "src/arm64/lithium-codegen-arm64.h"
 #include "src/hydrogen-osr.h"
@@ skipping 2542 matching lines @@
   LOperand* temp1 = TempRegister();
   LOperand* temp2 = TempRegister();
   LTrapAllocationMemento* result =
       new(zone()) LTrapAllocationMemento(object, temp1, temp2);
   return AssignEnvironment(result);
 }
 
 
 LInstruction* LChunkBuilder::DoTypeof(HTypeof* instr) {
   LOperand* context = UseFixed(instr->context(), cp);
-  // TODO(jbramley): In ARM, this uses UseFixed to force the input to x0.
-  // However, LCodeGen::DoTypeof just pushes it to the stack (for CallRuntime)
-  // anyway, so the input doesn't have to be in x0. We might be able to improve
-  // the ARM back-end a little by relaxing this restriction.
-  LTypeof* result =
-      new(zone()) LTypeof(context, UseRegisterAtStart(instr->value()));
+  LOperand* value = UseFixed(instr->value(), x3);
+  LTypeof* result = new (zone()) LTypeof(context, value);
   return MarkAsCall(DefineFixed(result, x0), instr);
 }
 
 
 LInstruction* LChunkBuilder::DoTypeofIsAndBranch(HTypeofIsAndBranch* instr) {
   // We only need temp registers in some cases, but we can't dereference the
   // instr->type_literal() handle to test that here.
   LOperand* temp1 = TempRegister();
   LOperand* temp2 = TempRegister();
 
@@ skipping 173 matching lines @@
     HAllocateBlockContext* instr) {
   LOperand* context = UseFixed(instr->context(), cp);
   LOperand* function = UseRegisterAtStart(instr->function());
   LAllocateBlockContext* result =
       new(zone()) LAllocateBlockContext(context, function);
   return MarkAsCall(DefineFixed(result, cp), instr);
 }
 
 
 } }  // namespace v8::internal