RFR: 8227505: SuperWordLoopUnrollAnalysis may lead to over loop unrolling
fujie at loongson.cn
Thu Aug 22 03:53:23 UTC 2019
Thanks for your review and comments.
On 2019/8/22 上午3:37, Deshpande, Vivek R wrote:
> The 2nd compilation(recompilation) of doit2 generates the code which does not use full vector width
I don't understand why we must compile with vector-512 since you didn't
share the performance of vector-256 and vector-512 respectively.
As for my reproducer, when vector-128 is used, performance becomes
much slower than vector-64.
Does vector-512 runs much faster than vector-256 on your manchine?
Could you please share the detailed performance data?
> and also does not unroll after vectorization.
Sorry. I can't reproduce this issue on my computer.
Here is the compilation log of my testing.
Probably this issue can be only triggered on an AVX-512 machine.
I will investigate it once my AVX-512 machine is ready.
If I missed anything please let me know.
Thanks a lot.
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