[arm] Recognize comparisons of shifts with zero.

src/arm/macro-assembler-arm.h

 // 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.
 
 #ifndef V8_ARM_MACRO_ASSEMBLER_ARM_H_
 #define V8_ARM_MACRO_ASSEMBLER_ARM_H_
 
 #include "src/assembler.h"
 #include "src/frames.h"
 #include "src/globals.h"
@@ skipping 134 matching lines @@
   void Usat(Register dst, int satpos, const Operand& src,
             Condition cond = al);
 
   void Call(Label* target);
   void Push(Register src) { push(src); }
   void Pop(Register dst) { pop(dst); }
 
   // Register move. May do nothing if the registers are identical.
   void Move(Register dst, Handle<Object> value);
   void Move(Register dst, Register src, Condition cond = al);
-  void Move(Register dst, const Operand& src, Condition cond = al) {
-    if (!src.is_reg() || !src.rm().is(dst)) mov(dst, src, LeaveCC, cond);
+  void Move(Register dst, const Operand& src, SBit sbit = LeaveCC,
+            Condition cond = al) {
+    if (!src.is_reg() || !src.rm().is(dst) || sbit != LeaveCC) {
+      mov(dst, src, sbit, cond);
+    }
   }
   void Move(DwVfpRegister dst, DwVfpRegister src);
 
   void Load(Register dst, const MemOperand& src, Representation r);
   void Store(Register src, const MemOperand& dst, Representation r);
 
   // Load an object from the root table.
   void LoadRoot(Register destination,
                 Heap::RootListIndex index,
                 Condition cond = al);
@@ skipping 1455 matching lines @@
 #define __FILE_LINE__ __FILE__ ":" CODE_COVERAGE_TOSTRING(__LINE__)
 #define ACCESS_MASM(masm) masm->stop(__FILE_LINE__); masm->
 #else
 #define ACCESS_MASM(masm) masm->
 #endif
 
 
 } }  // namespace v8::internal
 
 #endif  // V8_ARM_MACRO_ASSEMBLER_ARM_H_