Revert r4782. Fix issues 728, 732.

src/arm/ic-arm.cc

 // Copyright 2006-2008 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 816 matching lines @@
   __ bind(&check_string);
   // The key is not a smi.
   // Is it a string?
   // r0: key
   // r1: receiver
   __ CompareObjectType(r0, r2, r3, FIRST_NONSTRING_TYPE);
   __ b(ge, &slow);
 
   // Is the string an array index, with cached numeric value?
   __ ldr(r3, FieldMemOperand(r0, String::kHashFieldOffset));
-  __ tst(r3, Operand(String::kIsArrayIndexMask));
-  __ b(ne, &index_string);
+  __ tst(r3, Operand(String::kContainsCachedArrayIndexMask));
+  __ b(eq, &index_string);
 
   // Is the string a symbol?
   // r2: key map
   __ ldrb(r3, FieldMemOperand(r2, Map::kInstanceTypeOffset));
   ASSERT(kSymbolTag != 0);
   __ tst(r3, Operand(kIsSymbolMask));
   __ b(eq, &slow);
 
   // If the receiver is a fast-case object, check the keyed lookup
   // cache. Otherwise probe the dictionary.
@@ skipping 1076 matching lines @@
   GenerateMiss(masm);
 }
 
 
 #undef __
 
 
 } }  // namespace v8::internal
 
 #endif  // V8_TARGET_ARCH_ARM