RFR (XS) CR 8058643: (str) Re-examine hashCode implementation

Xueming Shen xueming.shen at oracle.com
Wed Sep 17 16:52:12 UTC 2014

You're correct. I was confused by the hash_code() in javaClass that I'm 
recently working on:-)
that is for those constants only.


On 9/17/14 9:43 AM, Aleksey Shipilev wrote:
> Hi Xueming,
> On 09/17/2014 08:13 PM, Xueming Shen wrote:
>> String.hashCode() has intrinsics,
> No, we have no intrinsics for String.hashCode. We do have a native
> implementation for VM internal purposes though, but it's irrelevant here.
>> so I don't think  we are seeing the real performance "difference" of
>> the implementations.
> No, we are seeing the difference, but it is about consistently and
> slightly different code generation, see the disassemblies linked in the
> bug report. Really, the performance run was to look out for regressions,
> and there is no indication there is one.
>> My guess is the original one probably is faster.
> No, it is not. Btw, that guess is inconsistent with a hypothesis we have
> intrinsics for String.hashCode() ;)
> Thanks,
> -Aleksey.

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