Fix zero hash handling on ARM.

src/ia32/code-stubs-ia32.cc

 // Copyright 2011 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 6073 matching lines @@
   __ add(hash, scratch);
   // hash ^= hash >> 11;
   __ mov(scratch, hash);
   __ shr(scratch, 11);
   __ xor_(hash, scratch);
   // hash += hash << 15;
   __ mov(scratch, hash);
   __ shl(scratch, 15);
   __ add(hash, scratch);
 
-  uint32_t kHashShiftCutOffMask = (1 << (32 - String::kHashShift)) - 1;
-  __ and_(hash, kHashShiftCutOffMask);
+  __ and_(hash, String::kHashBitMask);
 
   // if (hash == 0) hash = 27;
   Label hash_not_zero;
-  __ test(hash, hash);
   __ j(not_zero, &hash_not_zero, Label::kNear);
-  __ mov(hash, Immediate(27));
+  __ mov(hash, Immediate(StringHasher::kZeroHash));
   __ bind(&hash_not_zero);
 }
 
 
 void SubStringStub::Generate(MacroAssembler* masm) {
   Label runtime;
 
   // Stack frame on entry.
   //  esp[0]: return address
   //  esp[4]: to
@@ skipping 1234 matching lines @@
                                  false);
   __ pop(edx);
   __ ret(0);
 }
 
 #undef __
 
 } }  // namespace v8::internal
 
 #endif  // V8_TARGET_ARCH_IA32