[PATCH] D134168: [RISCV] Make preferred alignment of PointerArgs for MemIntrinsic

[Jessica Clarke via Phabricator via llvm-commits]

jrtc27 added a comment.

In D134168#3801753 <https://reviews.llvm.org/D134168#3801753>, @JojoR wrote:

> In D134168#3801742 <https://reviews.llvm.org/D134168#3801742>, @jrtc27 wrote:
>
>>> Set default preferred alignment for MemIntrinsic like memcpy according to arch32 or arch64,
>>> it will improve performance.
>>
>> What are arch32 and arch64?
>>
>>> e.g. dhrystone with "-O2" boosts performance by 50% on arch RV32.
>>
>> On what implementation? Does this affect actually-useful benchmarks, not just dhrystone? I would assume so, but it'd be more useful to get numbers for meaningful benchmarks rather than ones people should've long since abandoned.
>
> I think WORD_SIZE as preferred alignment is basic behavior to improve performance (use lw/sw instead of lb/sb), and dhrystone gets good performance benefit from this patch,
> some other useful benchmarks are up slightly (< 5%), I do not list here so.

I'm not saying it's a bad idea, I'm just saying that the 50% isn't a very useful figure to quote as it's unlikely to be representative of real-world performance, so some less awful benchmarks would be more meaningful and helpful to quote.


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