[PATCH] D106494: WIP: [AArch64][GlobalISel] Legalize ctpop s128

[Jon Roelofs via Phabricator via llvm-commits]

jroelofs added a comment.

In D106494#2898756 <https://reviews.llvm.org/D106494#2898756>, @paquette wrote:

> Do you have any idea of how to improve the zext behaviour?

I was thinking about making `narrowScalar` do: `zext(add(trunc(ctpop(hi)), trunc(ctpop(lo)))` with the hope that some combine folds the inner `trunc(zext(ctpop(x))) => ctpop(x)`, but I haven't tried this yet.


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