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

Jim Graham james.graham at oracle.com
Tue May 26 22:49:09 UTC 2015

Compilers have also gotten really really good at recognizing memory copy 
loops and applying the same optimizations automatically depending on the 
optimization level.

I'd really prefer to just leave this code alone and maybe find a way to 
tag the line to silence the warnings from the tool.  If we must replace 
the code, we would need to do performance benchmarks in any case...


On 5/26/2015 12:58 PM, Clemens Eisserer wrote:
> Hi Jim,
>> If there is no way to silence the tool, then I'd recommend hard-coding our
>> own "dumb copy loop" instead so that the behavior continues to match what
>> memcpy should have been doing.
> Isn't performance/throughput a concern for this case?
> Mamcpy is usually highly tuned with hand-optimized SIMD assembly, most
> likely reverting to a simply loop will not produce nearly as good
> code.
> Br, Clemens

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