[PATCH] D134780: [AMDGPU] Add MIMG NSA threshold configuration attribute

[Carl Ritson via Phabricator via llvm-commits]

critson added a comment.

In D134780#3820209 <https://reviews.llvm.org/D134780#3820209>, @foad wrote:

> Seems reasonable.
>
> I would also be in favour of changing the default to 2. That would tend to introduce fewer "mov"s to shuffle data around, at the expense of using a larger encoding on average for mimg instructions. But I think that is a good trade-off to make for the sake of performance.

Thank you for the quick review!
I did test the idea of using default 2, but I am not convinced yet that the benefit is universal enough.
Out of ~20000 pipelines, ~2000 had higher VGPR usage with threshold 2 and ~1000 had lower VGPR usage.
When VGPR usage decreases, it does so more beneficial ways though.
Spilling decreased in 2 pipelines, and only increased in 1.


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