A64: Tidy up VisitForOfStatement

src/a64/full-codegen-a64.cc

 // Copyright 2013 the V8 project authors. All rights reserved.
 // Redistribution and use in source and binary forms, with or without
 // modification, are permitted provided that the following conditions are
 // met:
 //
 //     * Redistributions of source code must retain the above copyright
 //       notice, this list of conditions and the following disclaimer.
 //     * Redistributions in binary form must reproduce the above
 //       copyright notice, this list of conditions and the following
 //       disclaimer in the documentation and/or other materials provided
@@ skipping 1251 matching lines @@
   Comment cmnt(masm_, "[ ForOfStatement");
   SetStatementPosition(stmt);
 
   Iteration loop_statement(this, stmt);
   increment_loop_depth();
 
   // var iterator = iterable[@@iterator]()
   VisitForAccumulatorValue(stmt->assign_iterator());
 
   // As with for-in, skip the loop if the iterator is null or undefined.
-  __ CompareRoot(x0, Heap::kUndefinedValueRootIndex);
-  __ B(eq, loop_statement.break_label());
-  __ CompareRoot(x0, Heap::kNullValueRootIndex);
-  __ B(eq, loop_statement.break_label());
+  Register iterator = x0;
+  __ JumpIfRoot(iterator, Heap::kUndefinedValueRootIndex,
+                loop_statement.break_label());
+  __ JumpIfRoot(iterator, Heap::kNullValueRootIndex,
+                loop_statement.break_label());
 
   // Convert the iterator to a JS object.
   Label convert, done_convert;
-  __ JumpIfSmi(x0, &convert);
-  __ CompareObjectType(x0, x10, x11, FIRST_SPEC_OBJECT_TYPE);
+  __ JumpIfSmi(iterator, &convert);
+  __ CompareObjectType(iterator, x1, x1, FIRST_SPEC_OBJECT_TYPE);
   __ B(ge, &done_convert);
   __ Bind(&convert);
-  __ Push(x0);
+  __ Push(iterator);
   __ InvokeBuiltin(Builtins::TO_OBJECT, CALL_FUNCTION);
   __ Bind(&done_convert);
-  __ Push(x0);
+  __ Push(iterator);
 
   // Loop entry.
   __ Bind(loop_statement.continue_label());
 
   // result = iterator.next()
   VisitForEffect(stmt->next_result());
 
   // if (result.done) break;
   Label result_not_done;
   VisitForControl(stmt->result_done(),
@@ skipping 3666 matching lines @@
   return previous_;
 }
 
 
 #undef __
 
 
 } }  // namespace v8::internal
 
 #endif  // V8_TARGET_ARCH_A64