[OpenJDK 2D-Dev] [9] Review Request: 8080847 Copying of overlapping memory should be improved in java2d

Jim Graham james.graham at oracle.com
Thu May 28 00:06:59 UTC 2015

Where do you see evidence that it can crash?


On 5/27/2015 3:54 AM, Andrew Haley wrote:
> On 05/27/2015 11:36 AM, Sergey Bylokhov wrote:
>> On 26.05.15 21:27, Jim Graham wrote:
>>> Undefined doesn't mean "may crash" in this case, it means that the
>>> contents of memory may not match what you would expect if the regions
>>> overlap because it is just a dump copy loop that does not do any
>>> aliasing checks.
>> Since it is undefined it can crash, but even if it is not, it can
>> produce the different results for the same application on different cpu.
> Definitely.  It certainly can crash.  There is no way that we should
> tolerate UB in any code which is part of Java.  We can just use
> memmove().
> Andrew.

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