[PATCH] D129715: [LoongArch] Heuristically load FP immediates by movgr2fr from materialized integer

Thu Jul 14 20:08:08 PDT 2022

gonglingqin added a comment.

In D129715#3653892 <https://reviews.llvm.org/D129715#3653892>, @xen0n wrote:

> I don't know if you did the experiments thoroughly and found out 2 is the optimal threshold (on SPEC2006), or if it was just an arbitrary choice ("拍脑袋").
>
> You could mention how the threshold was chosen, in case it is indeed arbitrary but others wrongly assume it's something related to micro-architecture details, or empirically verified.

In D129715#3653892 <https://reviews.llvm.org/D129715#3653892>, @xen0n wrote:

> I don't know if you did the experiments thoroughly and found out 2 is the optimal threshold (on SPEC2006), or if it was just an arbitrary choice ("拍脑袋").
>
> You could mention how the threshold was chosen, in case it is indeed arbitrary but others wrongly assume it's something related to micro-architecture details, or empirically verified.

I used 3A5000 on llvm13 to test materialized integer within 1,2 and 4 instructions.the results show that the performance is the best when using no more than 2 instructions. Maybe we should test the situation materialized integer within 3 instructions.

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