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Re: [PATCH 2/3][AArch64] Improve zero extend


Richard Earnshaw wrote:
> So under what circumstances does it lead to sub-optimal code?

If the cost is incorrect Combine can make the wrong decision, for example
whether to emit a multiply-add or not. I'm not sure whether this still happens
as Kyrill fixed several issues in Combine since this patch was written.

Wilco




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