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

[Andrew Haley]

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.