Unsafe for array access

John Rose john.r.rose at oracle.com
Wed May 7 15:56:19 UTC 2014

> On May 7, 2014, at 4:30 AM, Doug Lea <dl at cs.oswego.edu> wrote:

> Relatedly, it might be be nice to have an intrinsic boundsCheck(array, index)
> that could be used in such cases that implemented using the more efficient
> (using C): (unsigned)index >= (unsigned)array.length, plus relied on more
> efficient VM throw mechanics on failure.

We need an intrinsic like this for Arrays 2.0. Might as well do it now, since we have an immediate application. 

Counterpoint:  optimizer can and should generate similar code for plain user written range tests. 

Advice:  Do both, and the intrinsic will give everybody a clearer target to aim for. Unit test the intrinsic optimization, and several similar formulations. 

– John

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