Re: [PATCH v2] rs6000: fmr gets used instead of faster xxlor [PR93571]

[Surya Kumari Jangala via Gcc-patches]

On 25/02/23 3:20 pm, Ajit Agarwal via Gcc-patches wrote:
> Hello All:
> 
> Here is the patch that uses xxlor instead of fmr where possible.
> Performance results shows that fmr is better in power9 and 
> power10 architectures whereas xxlor is better in power7 and
> power 8 architectures. fmr is the only option before p7.
> 
> Bootstrapped and regtested on powerpc64-linux-gnu
> 
> Thanks & Regards
> Ajit
> 
>       rs6000: Use xxlor instead of fmr where possible
> 
>       Replaces fmr with xxlor instruction for power7 and power8
>       architectures whereas for power9 and power10 keep fmr
>       instruction.
> 
>       Perf measurement results:
> 
>       Power9 fmr:  201,847,661 cycles.
>       Power9 xxlor: 201,877,78 cycles.
>       Power8 fmr: 200,901,043 cycles.
>       Power8 xxlor: 201,020,518 cycles.

'fmr' is better than 'xxlor' for power8 according to the above numbers. Should 
we then replace fmr with xxlor?

-Surya