[PATCH] D123379: [AArch64] Cost all perfect shuffles entries as cost 1

[Sjoerd Meijer via Phabricator via llvm-commits]

SjoerdMeijer added a comment.

Thanks for the introduction to perfect shuffles! :-)

> The codegen will usually be better and the costs should be more precise (but it can get less second-order re-use of values from multiple shuffles, these cases should be fixed up in subsequent patches.

The approach looks sensible, but can you elaborate why codegen is better? This isn't that obvious to me, and by quickly eyeballing it I might even spotted some regressions.


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https://reviews.llvm.org/D123379