[RFC] cortex-a{53,57}-simd.md missing?

Ramana Radhakrishnan ramana.radhakrishnan@arm.com
Fri Feb 20 10:05:00 GMT 2015


> ;; Crude Advanced SIMD approximation.
> ;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;
>
> (define_insn_reservation "cortex_53_advsimd" 4
>     (and (eq_attr "tune" "cortexa53")
>          (eq_attr:q "is_neon_type" "yes"))
>     "cortex_a53_simd0")
>
> Does it mean that all AdvSIMD instructions for cortex-a53 are supposed
> to be of latency = 4?

Yes.

>
> In cortex-a57.md the description for "neon" instructions is more full,
> it contains a lot of statements for different SIMD instructions.
> It appeared in trunk just a month ago.

Yes.

>
> Are there any plans to release detailed pipeline descriptions for SIMD
> instructions for cortex-a53?
 > How can it influence the performance of the generated code?

No, we have no immediate plans. Obviously if we find a reason and 
workloads where such changes are merited it will be picked up.

That being said I believe the current description isn't too bad on the 
Cortex-A53 - it's definitely better than having none at all.


regards
Ramana


>
> --
> Best regards,
> Ilya Palachev
>
>



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