SuperWordLoopUnrollAnalysis and loop unrolling

[Vladimir Kozlov]

Try to run debug VM with -XX:+TraceSuperWordLoopUnrollAnalysis.

It could be https://bugs.openjdk.java.net/browse/JDK-8175096

Vladimir

On 4/12/17 10:22 AM, Andrew Haley wrote:
> If I set SuperWordLoopUnrollAnalysis=true, then AArch64 C2 stops after
> unrolling a simple loop 4 times.  If I set
> SuperWordLoopUnrollAnalysis=false, it stops after unrolling 16 times.
> Why is is that SuperWordLoopUnrollAnalysis limits unrolling in this
> way?
>
> The info says
> "Map number of unrolls for main loop via Superword Level Parallelism
> analysis" but that doesn't help me very much.  Only AArch64 and x86
> set this option.
>
> Thanks,
>
> Andrew.
>